AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 244 PM MDT FRI SEP 22 2006 .SHORT TERM... (TONIGHT AND SATURDAY) CURRENTLY...FIRST SHORTWAVE MOVED THROUGH THE REGION DURING THE MORNING AND EARLY AFTERNOON. SOME BANDING IN THE SHORTWAVE PRODUCE SOME LOCALLY HEAVY SNOW IN THE SOUTHWEST MOUNTAINS. THE SHORTWAVE AND ACCOMPANYING WEAK SURGE WAS ALSO ABLE TO TURN THE FLOW UPSLOPE FOR SOME PRECIPITATION ON THE INTERSTATE 25 CORRIDOR AND EASTERN MOUNTAINS. SOME SPOTTERS REPORTED SEVERAL TENTHS OF LIQUID AND SOME SPOTTERS IN THE EASTERN MOUNTAINS HAD A COUPLE INCHES OF SNOW. .TONIGHT...SECOND SHORTWAVE/PV LOBE OVER SOUTHWEST COLORADO WILL SWING THROUGH TONIGHT. CLOUD TOPS AHEAD OF THIS SECOND SHORTWAVE ARE WARMER THAN AHEAD OF THE FIRST SHORTWAVE...SUPPORTING THE IDEA OF DRIER AIR ALOFT. THIS SHORTWAVE WILL CONTINUE THE CHANCES FOR SNOW THIS EVENING...BUT WITH THE DRIER AIR AND NOT VERY FAVORABLE OROGRAPHICS...I WILL NOT EXTEND THE ADVISORY BEYOND 00Z. LAKE COUNTY WILL BE CLOSEST TO THE DEEPER MOISTURE...AND NORTHERLY FLOW AT 700MB IS NOT CONDUCIVE TO HEAVY SNOW. IF EVOLUTION CHANGES IN THE NEXT THREE HOURS...THAN EVENING SHIFT CAN EXTEND THE ADVISORY. I EXPECT MODEST ACCUMULATIONS OVERNIGHT...BUT NOT ENOUGH TO WARRANT EXTENDING THE ADVISORY. OTHER CONCERN IS THE EASTERN MOUNTAINS. ANOTHER WEAK SURGE WILL ACCOMPANY THE SHORTWAVE THIS EVENING. 12Z AND 18Z WRF HINT AT THE 700MB FLOW GOING NORTHEAST ALONG PORTIONS OF THE INTERSTATE 25 CORRIDOR. RUC ALSO HAS A SIMILAR IDEA. I INCREASED POPS TONIGHT TO LIKELY FOR THE EASTERN MOUNTAINS. I WOULD NOT BE SURPRISED TO GET ANOTHER ROUND WITH A FEW TENTHS OF LIQUID. GIVEN IT IS EARLY IN THE SEASON AND TEMPERATURES WILL NOT BE VERY COLD...SNOW ACCUMULATIONS SHOULD MOSTLY BE ON THE GRASS EXCEPT AT THE HIGHER ELEVATIONS. ON THE PLAINS...THE WRF...RUC AND GFS SUGGEST THE POTENTIAL FOR AN AREA OF PRECIPITATION ALONG THE FRONT...BUT IN DIFFERENT LOCATIONS. THIS SUGGESTS THE POSSIBILITY FOR A PERIOD OF RAIN ON THE PLAINS THIS EVENING...AND I INCREASED THE POPS TO SCATTERED DURING TH EVENING. .SATURDAY...ANOTHER TROUGH WILL MOVE IN FROM THE NORTH. OUR CWA WILL BE ON THE SOUTHERN FRINGES OF THE TROUGH...WITH BEST POPS TO THE NORTH. THERE WILL BE ENOUGH MOISTURE AND INSTABILITY FOR MOUNTAINS SHOWERS. ON THE PLAINS...LOWER LEVELS WILL BE DRY WITH THE NORTHWEST FLOW...BUT THERE WILL STILL BE THE CHANCE FOR A FEW SHOWERS. TEMPERATURES WILL REMAIN BELOW AVERAGE. --PGW-- .LONG TERM... (SATURDAY NIGHT THROUGH THURSDAY) SATURDAY NIGHT...NAM/WRF FORECASTS TROUGH AXIS TO BE OVER EXTREME SOUTHEAST COLORADO WITH CYCLONIC FLOW ESPECIALLY ACROSS THE SOUTHEAST PLAINS. FAIRLY TIGHT PRESSURE GRADIENT SHOULD MAKE FOR A BREEZY EVENING ACROSS THE PLAINS...WITH SOME GUSTS ABOVE 30 MPH... BEFORE WINDS TAPER OFF IN THE LATE EVENING. SLIGHT CHANCE POPS EARLY...THEN JUST OVER THE HIGHER TERRAIN LATER ON SEEMS REASONABLE. SUNDAY DEPICTED TO BE A RATHER COOL DAY...WITH 700MB TEMPERATURES ONLY NEAR 0C IN THE EAST TO AROUND 4C OUT WEST. ALSO...THE LAPSE RATES IN THE AFTERNOON GET A BIT STEEP IN THE HIGH TERRAIN WITH SOME VERY LIMITED MOISTURE...SO THERE COULD BE A FEW LIGHT SHOWERS ABOVE 9K FEET. ANY VIRGA OR LIGHT SHOWERS SHOULD END QUICKLY IN THE EVENING...PAVING THE WAY FOR A COOL MONDAY MORNING. TEMPERATURES SHOULD DROP INTO THE TEENS AND 20S ACROSS THE MOUNTAINS AND HIGH VALLEYS...BUT STAY ABOVE FREEZING IN THE EAST. MONDAY AND TUESDAY...RIDGING FORECAST BY GFS AND NAM/WRF WITH MID LEVEL TEMPERATURES RISING SOME 4 TO 6 DEGREES CELSIUS OVER THE AREA. THAT SHOULD TRANSLATE INTO 70S TO LOWER 80S ACROSS THE PLAINS AND 40S WAY UP HIGH IN THE MOUNTAINS TO AROUND 70 IN THE HIGH VALLEYS. TUESDAY NIGHT AND WEDNESDAY THE GFS...WHICH HAS HAD FAIRLY GOOD RUN TO RUN CONTINUITY...SHOWS A VIGOROUS SHORTWAVE ROTATING AROUND THE UPPER LOW OVER EASTERN CANADA. IF THIS PANS OUT...A QUICK SHOT OF COOL AIR WILL INVADE SOUTHEAST SECTIONS OF OUR AREA WEDNESDAY. HAVE KEPT POPS ON WEDNESDAY IN THE SLIGHT CHANCE CATEGORY...ALONG WITH LOWER TEMPERATURES IN THE PLAINS. WOULD BE COOL ENOUGH IN THE HIGHER ELEVATIONS OF THE EASTERN MOUNTAINS FOR SOME LIGHT SNOW ACCUMULATIONS...IF PRECIPITATION BECOMES MORE PROBABLE. ON THURSDAY...THE SHORTWAVE PASSES ON TO THE SOUTHEAST...AND BY AFTERNOON MID LEVELS TEMPERATURES REBOUND NICELY WITH DRIER CONDITIONS...SO GOING FORECAST OF DRY AND MILDER LOOKS GOOD. -TLM- && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY UNTIL 6 PM MDT THIS AFTERNOON FOR COZ058-COZ059-COZ060-COZ061-COZ064-COZ065-COZ066-COZ067-COZ068. && $$ 06/13 co WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL 942 AM EDT FRI SEP 22 2006 .UPDATE...12Z RAOB AND SURFACE OBSERVATIONAL DATA INDICATES THAT THE AIR MASS ACROSS THE FORECAST AREA HAS MOISTENED UP SOME FROM YESTERDAY WITH DEW POINTS NOW RUNNING IN THE UPPER 60S TO LOWER 70S WITH PW'S ~1.4" WHICH IS UP ABOUT HALF INCH FROM YESTERDAY. THIS SUBTLE INCREASE IN MOISTURE ALONG WITH DAYTIME HEATING SHOULD RESULT IN SOME ISOLATED SHOWER AND THUNDERSTORM ACTIVITY ALONG THE SEA BREEZE CIRCULATIONS LATER THIS AFTERNOON. CURRENTLY HAVE 20% POPS IN THE FORECAST FROM MANATEE TO HIGHLANDS COUNTY SOUTH FOR THE LATE AFTERNOON HOURS...BUT WILL EXPAND THIS LOW POP MENTION NORTHWARD INTO HILLSBOROUGH AND POLK COUNTIES AS WELL GIVEN THE LATEST RAOB...GFS/NAM AND RUC OUTPUT. ACROSS THE NORTHERN FORECAST AREA LINGERING MORE PRONOUNCED DRY SUBSIDENT AIR MASS PER KJAX SOUNDING DATA WILL SUPPORT DRY AND WARM CONDITIONS. WILL ADD THE LOW RAIN CHANCE (20%) POSSIBILITY TO THE COUNTIES MENTION ABOVE IN A LATE MORNING ZONE UPDATE...OTHERWISE NO OTHER CHANGES EXPECTED. && .MARINE...A LIGHT EAST TO SOUTHEAST WIND FLOW AND SLIGHT SEAS WITH AN ONSHORE SEA BREEZE COMPONENT DEVELOPING NEAR SHORE IS EXPECTED OVER THE ADJACENT GULF COASTAL WATERS THIS AFTERNOON. ONGOING FORECAST IN GOOD SHAPE WITH NO CHANGES EXPECTED IN THE NEXT FORECAST ISSUANCE LATER THIS MORNING. && .AVIATION...VFR CONDITIONS WILL CONTINUE AT ALL TAF SITES TODAY AND TONIGHT AS HIGH PRESSURE REMAINS OVER THE AREA...HOWEVER BRIEF MVFR CONDITIONS WILL BE POSSIBLE LATE THIS AFTERNOON OVER THE CENTRAL AND SOUTHERN TAF SITES AS A FEW SHOWERS OR THUNDERSTORMS DEVELOP ALONG THE SEA BREEZE. && .FIRE WEATHER...MAY SEE A FEW POCKETS OF MARGINALLY LOW HUMIDITY VALUES OVER INTERIOR LOCATIONS THIS AFTERNOON...BUT OVERALL INCREASING LOW LEVEL MOISTURE (DEW POINTS UPPER 60S TO LOWER 70S) SHOULD PRECLUDE ANY RED FLAG CONDITIONS. && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/MARINE/FIRE WEATHER...JCM AVIATION...AR fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 745 PM EDT FRI SEP 22 2006 .UPDATE... AM LOWERING POPS FOR THE OVERNIGHT HOURS ONE OR MORE CATEGORIES IN MOST CASES. WILL COMPROMISE BETWEEN RUC WHICH SAYS POPS SHOULD GO TO ZERO BY MIDNIGHT WITH GFS WHICH HOLDS ONTO 40 AND 50 PERCENT POPS OVERNIGHT. ALSO...REDUCED MENTION OF TSRA WORDING. A LITTLE BIT WORRIED ABOUT POSSIBLE REDEVELOPMENT LATER TONIGHT ACROSS THE NW/W CENTRAL AREAS...BUT ISOLD TSRA SHOULD SUFFICE FOR NOW. ALSO LOWERED POPS ONE CATEGORY FOR SAT AS WELL AS STRONG UPPER RIDGE INTRUDES FROM THE SE AND PUSHES BEST CHANCE OF SHRA/TSRA BACK TO THE NW INTO MIDDLE TN. SHOULD TURN OUT TO BE A FAIRLY NICE SATURDAY FOR MUCH OF THE CWA AFTERALL...AND QUITE WARM AS WELL. DID NOT MAKE ANY SIGNIFICANT CHANGES TO TEMPERATURES AT THIS TIME. && .SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT) STRONG STORMS IN ALABAMA DISSIPATED ALMOST COMPLETELY AS THEY MOVED TOWARD THE GA BORDER. NOT EVEN ANY SWAS REQUIRED IN OUR CWA AS BASICALLY ONLY LIGHT SHRA OR EVEN VIRGA MADE IT ACROSS THE FFC CWA. SLIGHTLY DRIER AIR MASS WITH DEWPOINTS MOSTLY IN THE 65 TO 68 RANGE AS COMPARED TO THE 70-72 DEWPOINTS IN AL MADE ALL THE DIFFERENCE. AXIS OF BETTER INSTABILITY REMAINED ALONG AND WEST OF THE GA/AL BORDER THROUGHOUT. THIS DOES NOT CHANGE IN THE SHORT TERM. RUC MODEL SHOWS LITTLE OR NO PRECIP ACROSS THE FFC CWA OVERNIGHT...ALTHOUGH THE GFS DOES KEEP AN AREA OF MOISTURE AND INSTABILITY CONCENTRATED ACROSS N GA OVERNIGHT. HOWEVER...THE GFS SHOWED THE BEST AREA OF PRECIP FOR THE AFTERNOON HOURS ACROSS NE GA...AND THIS DID NOT VERIFY WELL AT ALL. NAM AGREES WITH RUC IN HOLDING OFF PRECIP UNTIL AFTER 12Z. OVERALL...NOT EXPECTING MUCH OVERNIGHT ACROSS THE CWA...BUT CANNOT RULE OUT SOME SHRA LATER TONIGHT AS WARM FRONT STARTS TO LIFT NE. KEY TO HOLDING OFF SHRA/TSRA ACROSS THE CWA WILL BE AMPLIFYING UPPER RIDGE OFF THE SE U.S. COAST. THIS WILL TEND TO PUSH THE DYNAMICS AND INSTABILITY BACK TO THE NW ACROSS TN/KY AND FURTHER AWAY FROM GA THROUGH SAT. THE RIDGE WILL THEN FLATTEN AND MOVE BACK TO THE SE SUN AND ALLOW THE ENTIRE UPPER SYSTEM TO SWEEP THROUGH THE AREA AT THAT TIME. THIS IS NOT AN IMPRESSIVE SYSTEM FOR OUR CWA AND THE THREAT OF SEVERE APPEARS MINIMAL TO ME. UPPER TROUGH IS POSITIVELY TILTED AND SHEARS OUT WITH TIME. THE BEST INSTABILITY ACTUALLY EXISTS SAT NIGHT/EARLY SUN. I COULD WELL SEE A SITUATION WHERE THE BULK OF THE SHRA/TSRA COMES THROUGH EARLY SUN...LEAVING THE AREA WITH EXTENSIVE CLOUD COVER AND RAIN COOLED AIR IN PLACE...THUS SIGNIFICANTLY LIMITING THE THREAT OF SEVERE. IN ADDITION...HEAVY RAIN SHOULD NOT BE A THREAT EITHER AS THE SYSTEM MOVES THROUGH FAIRLY QUICKLY. .LONG TERM...(MONDAY THROUGH FRIDAY) A VERY DRY AIR MASS WILL SPREAD ACROSS THE AREA EARLY MON AND PREVAIL THROUGH MIDWEEK. VERY DRY WNW DOWNSLOPE FLOW WILL PREVAIL ALOFT. TEMPERATURES WILL REMAIN NEAR SEASONAL AS THERE IS REALLY LITTLE COOLING BEHIND THIS CURRENT SYSTEM. ANOTHER BROAD UPPER TROUGH WILL DEVELOP TOWARD THE END OF THE WEEK BRINGING THE NEXT WEATHER SYSTEM TO THE AREA. THIS APPEARS TO BE A FAIRLY SHARP TROUGH...AND APPEARS MORE SIGNIFICANT ON THE 18Z RUN THAN IT DID ON THE 12Z RUN. INSTABILITY PARAMETERS NOT IMPRESSIVE BUT DYNAMICS FAIRLY INTERESTING. THIS SYSTEM WILL NEED TO BE WATCHED AS THE WEEK PROGRESSES. IN ADDITION...MUCH COLDER AIR FOLLOWS THIS SYSTEM WITH THE FIRST SIGN OF 0C AT 850MB INTO N GA BY NEXT WEEKEND. WILL SEE...AS GFS OFTEN OVERDOES COOLING IN THE EXTENDED...AS WELL AS THE STRENGTH OF SUCH SYSTEMS. && .AVIATION...SHOWERS AND STRONG THUNDERSTORMS DEVELOPING IN VICINITY OF WARM FRONT STRETCHING FROM SOUTHWEST GA INTO NORTHERN AL. THUNDERSTORMS SHOULD DIMINISH AFTER SUNSET...BUT ISOLATED CONVECTION POSSIBLE ANYWHERE ACROSS NORTHWEST GA THIS EVENING. SCT TO BKN STRATOCU BETWEEN 3 AND 4THSD FT THIS EVENING SHOULD LOWER AFTER MIDNIGHT TO AROUND 15 HND TO 2THSD FT BY SUNRISE. WINDS SHOULD REMAIN LIGHT SOUTHEAST AS HIGH PRESSURE REMAINS CENTERED OFF MID ATLANTIC COAST. VISIBILITY GENERALLY UNRESTRICTED EXCEPT IN SHOWERS AND LOCALLY 3 TO 5SM IN FOG AFTER MIDNIGHT. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 66 86 67 85 / 20 30 30 60 ATLANTA 68 84 69 81 / 20 40 30 60 BLAIRSVILLE 65 80 66 78 / 30 30 40 60 CARTERSVILLE 66 85 66 79 / 30 40 40 60 COLUMBUS 70 91 71 86 / 30 30 20 60 GAINESVILLE 66 83 67 80 / 30 30 40 60 MACON 67 90 69 89 / 20 20 20 30 ROME 69 87 68 81 / 30 40 50 60 PEACHTREE CITY 65 86 66 83 / 20 30 30 60 VIDALIA 68 91 69 89 / 5 5 10 30 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 19/41 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 645 PM CDT FRI SEP 22 2006 .DISCUSSION FOR AFTERNOON GRIDS/ZFP... 335 PM CDT MAIN FOCUS HAS BEEN PLACED ON NR TERM OF FCST DUE TO ANTICIPATED CONVECTIVE DVLPMT. LASTEST VIS SATLT LOOPS SHOW DEEP MOISTURE CONTG TO ADVECT RPDLY NWD AHD OF SHRT WAVE TROF AND ASSD JET MAX NOW RUNNING FROM ERN IA-NERN MO AND ON INTO XTRM NWRN AR. THIS FEATURE IS EXPECTED TO ACT ON INCRSGLY UNSTABLE AIR E OF MS RVR AND TRIGGER ADDITIONAL STG TO SVR TSTM DVLPMT RMNDR OF THIS AFTN. THESE STORMS WILL ALSO BE MOVG INTO STGLY SHEARED ENVIRONMENT ALG/JUST AHD OF WARM FRONT RUNNING ACRS NRN IL/NWRN IND...ALG/S OF I-80. THIS IS EXPECTED TO CAUSE STMS THAT DO DVLP TO QUICKLY DVLP ROTATION AND THIS ASPECT OF DVLPMT HAS ALREADY BEEN NOTED WITH A FEW UPDRAFTS THAT HAVE ALREADY BEGUN TO POP UP OVR NRN LASALLE CO. LTL CHG TO RMNDR FCST. MERZLOCK && .AVIATION DISCUSSION REGARDING 00Z TAFS... 645 PM CDT THUNDERSTORMS RADIDLY MOVING OUT OVER LAKE MI AND DISIPATING OVER NRN IL. WILL KEEP TEMPO OR VCNTY GROUP FOR THUNDERSTORMS IN TAFS EXCEPT RFD FOR NEXT COUPLE HOURS. BELIEVE SEVERE THREAT IS GREATLY DIMINISHING WITH SUNSET. THEN WILL KEEP FORECAST DRY FOR THE OVERNIGHT. SATELLITE AND SURFACE OBS SHOWING NICE DRYING ACROSS WRN IL AND ERN IA. WINDS ALL OVER THE PLACE IN THE WAKE OF THE STORMS BUT SSWLY GARDIENT AROUND 10 KNOTS SHOULD RE-ESTABLISH ITSELF IN NEXT HOUR OR TWO. WILL FOLLOW RUC WITH WINDS BECOMING LIGHT SW LATE TONIGHT THEN BACKING SE SATURDAY. ANOTHER ROUND OF THUNDERSTORMS EXPECTED SATURDAY AFTERNOON AND WILL COVER THIS WITH A PROB GROUP FOR NOW. ALLSOPP && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...SMALL CRAFT ADVISORY FROM 1 AM TONIGHT THROUGH LATE FRIDAY NIGHT FOR THE ILLINOIS NEAR SHORE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 948 PM CDT FRI SEP 22 2006 .DISCUSSION... QUESTIONS THIS EVENING ARE WHETHER PRECIP WILL DEVELOP OVERNIGHT. 00Z GUIDANCE IS COMING IN AND CONTINUES TO SHOW ISENTROPIC LIFT DEVELOPING ACROSS SOUTHERN AND EAST KANSAS. THIS IS SEEN IN THE MODELS AS THE 850 WINDS BACK ACROSS NORTHEASTERN OK AND SOUTHWESTERN MO. WHILE MID LEVEL MOISTURE LOOKS TO BE PLENTIFUL...LOW LEVELS REMAIN RELATIVELY DRY IN THE FORECAST SOUNDINGS FROM THE RUC AND NAM. THERE IS ALSO CONCERN WHETHER DEEP CONVECTION ACROSS EASTERN OK WILL LIMIT THE AMOUNT OF MOISTURE RETURNING WITH THE ISENTROPIC LIFT. HAVE ADJUSTED POPS DOWN SLIGHTLY BUT WILL CONTINUE THE CHANCE FOR LIGHT SHOWERS DEVELOPING OVERNIGHT AND CONTINUING INTO THE MORNING SATURDAY. TOOK OUT THE MENTION OF THUNDERSTORMS SINCE MID LEVEL LAPSE RATES SHALLOW UP TO AROUND 5 C/KM. THERE REALLY ARE NOT MANY AVIATION CONCERNS THIS EVENING. EXPECT CEILINGS AND VSBY TO REMAIN VFR. WILL KEEP ANY MENTION OF SHOWERS AS VCNTY...AND MONITOR TRENDS TO SEE WHERE SHOWERS WILL DEVELOP. LOW MVFR OR IFR CEILINGS LOOK TO HOLD OFF UNTIL SATURDAY NIGHT AS WRAP AROUND JUNK MOVES IN ON THE BACK SIDE OF THE UPPER LEVEL SYSTEM. && WOLTERS .PREV DISCUSSION /310 PM FRI/... LATEST SATELLITE LOOP SHOWS UPPER LOW SPINNING OVER EASTERN SOUTH DAKOTA WITH A SHORTWAVE TROUGH MOVING INTO WESTERN COLORADO AT 19Z. SURFACE LOW WAS OVER SOUTHEASTERN SOUTH DAKOTA. FOR TONIGHT THE SHORTWAVE TROUGH WILL EJECT OUT OF THE ROCKIES INTO THE CENTRAL PLAINS. LAYER MOISTURES WILL INCREASE ACROSS CENTRAL AND EASTERN KANSAS AS 850 MB WINDS BACK AHEAD OF THE UPPER TROUGH. THIS ALONG WITH WARM ADVECTION AND INCREASING DYNAMICS WILL INCREASE POPS AFTER MIDNIGHT TO NEAR 50 PERCENT ACROSS THE AREA. MODELS SUGGEST THAT BEST CHANCE FOR PRECIPITATION WILL BE AFTER 06Z INTO MID MORNING SATURDAY. MODEL TIMING WITH THE ENDING OF THE PRECIPITATION DIFFERS BETWEEN THE GFS...SREF AND THE NAM. THE NAM IS SLOWER WHILE THE GFS IS FASTER AND PROGRESSIVE WITH THE TROUGH. HAVE GONE WITH A GFS SOLUTION FOR SATURDAY BUT HAVE ADJUSTED THE TIMING OF THE ENDING OF THE PRECIPITATION SOME BY INCREASING POPS EARLY THEN GOING DRY BY MID DAY. LOWS TONIGHT LITTLE CHANCE WITH LOW TO MID 50S...COOLER ON SATURDAY WITH CLOUDS PRECIPITATION AND COOL ADVECTION. SATURDAY NIGHT AND SUNDAY...AGAIN...GENERALLY WENT ALONG WITH GFS SOLUTION IN PULLING SURFACE LOW INTO THE GREAT LAKES REGION FASTER WITH BETTER SUPPORT FROM OTHER FORECAST MODELS. NAM APPEARS TO BE A SLOW OUTLIER. ABUNDANT LOW LEVEL MOISTURE ON BACK SIDE OF THE SURFACE LOW WILL KEEP CLOUDS AROUND FOR MUCH OF THE DAY SUNDAY...ESPECIALLY ACROSS THE EASTERN CWA. GIVEN THE EXPECTANT CLOUDY SKIES...HELD HIGHS IN THE MID TO UPPER 60S. MONDAY AND TUESDAY...SURFACE LOW AND H5 TROUGH WILL CONTINUE TO MOVE NORTHEAST...WITH RIDGING MOVING BACK IN ALOFT. SURFACE HIGH WILL MOVE ACROSS THE SOUTHERN PLAINS...BRINGING A QUICK WARM UP FOR THE AREA WITH A WEST TO SOUTHWEST WIND TAKING HOLD. H85 TEMPS QUICKLY SHOOT BACK INTO THE MID TEENS BY TUESDAY AFTN. SUNNY SKIES ON MONDAY AND TUESDAY WILL ALLOW HIGHS TO REBOUND TO THE MID 70S MONDAY...AND UPPER 70S/LOW 80S TUESDAY. WEDNESDAY...POTENT H5 WAVE WILL WORK SOUTH ACROSS THE UPPER PLAINS...WHICH WILL SUPPORT COLD FRONTAL PASSAGE THROUGH THE TOP CWA EARLY WEDS. FRONT WILL COME THROUGH DRY...BUT AS UPPER WAVE CONTINUES SOUTH...PRECIPITATION CHANCES WILL INCREASE. FRONT LOOKS TO BE PRETTY POTENT WITH A TIGHT BAROCLINIC ZONE. H85 TEMPS ARE FORECAST TO START OFF THE DAY AROUND 15C...WHILE ENDING THE DAY AROUND 2C. HIGH TEMPS WILL COME IN THE MORNING OR EARLY AFTN AT THE LATEST. THURSDAY AND FRIDAY...ANY LINGERING SHOWER ACTIVITY WILL COME TO AN END ACROSS THE SE CWA EARLY THU. EC AND GFS SIMILAR IN SHIFTING H5 TROUGH EAST WHILE BUILDING RIDGING OVER THE WESTERN TWO THIRDS OF THE COUNTRY. AT THE SURFACE...HIGH PRESSURE WILL PUSH ACROSS THE CENTRAL PLAINS. PERIOD LOOKS COOL AND TRANQUIL WITH A SLIGHT WARM UP ON FRIDAY AS WINDS SWITCH TO THE SOUTH. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 230 PM MDT FRI SEP 22 2006 .DISCUSSION...FORECAST PROBLEMS WILL BE CHANCE OF PRECIPITATION THROUGH SATURDAY...WINDS SATURDAY...AND TEMPERATURE RECOVERY AT THE BEGINNING OF THE WEEK BEFORE THE NEXT COOL DOWN. SATELLITE SHOWING AN AMPLIFIED BUT SOMEWHAT PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. BROAD AND COMPLICATED UPPER TROUGH OVER THE CENTRAL PORTION OF THE COUNTRY. SYSTEM THAT BROUGHT WIDESPREAD RAIN TO THE AREA YESTERDAY IS SPINNING OVER THE NORTH CENTRAL PORTION OF THE COUNTRY. SECOND...RATHER STRONG LOOKING SYSTEM...ROTATING AROUND THIS TROUGH IS MOVING THROUGH COLORADO. ALSO VERY STRONG JET IS MOVING IN FROM THE SOUTH AND WEST WITH THIS SYSTEM. AT JET LEVEL...JET SEGMENT OVER THE WESTERN PORTION OF THE COUNTRY WAS NOT SAMPLED WELL. IF SATELLITE/AIRCRAFT SPEEDS ARE CORRECT...MODELS INITIALIZED ABOUT 25 KNOTS TOO LOW. AT 18Z...THEY WERE DOING BETTER AND CLOSER WITH THE GFS DOING THE BEST ON THE 140 KNOT JET COMING IN FROM NORTHERN NEW MEXICO. AT MID LEVELS...OVERALL THROUGH 18Z...THE GFS/UKMET/RUC DID THE BEST ON THE TWO SYSTEMS OF INTEREST. THE NAM/WRF WAS NOT TOO FAR BEHIND. BASED ON PERFORMANCE THROUGH 18Z...AND JET STRUCTURE...WILL GO WITH A BLEND OF THE GFS AND UKMET. TONIGHT/SATURDAY...HIGHEST JET WINDS ROAR UP THE EAST SIDE OF THE UPPER TROUGH DURING THE NIGHT WHICH SYSTEM SHOULD KICK OUT FAIRLY FAST. LEFT FRONT QUADRANT OF JET TO OUR SOUTHWEST WILL MOVE ACROSS THE AREA DURING THE EVENING AS INCOMING SYSTEM ALSO MOVES THROUGH. SOUNDINGS AND OBSERVATIONS SHOW DRY LOW LEVELS...AND LIFT WILL HAVE TO OCCUR FOR A WHILE BEFORE PRECIPITATION BEGINS...AND BELIEVE IT WILL. HARD TO SAY WHERE ANY ONE SPOT WILL GET PRECIPITATION WITH MOISTURE AND LIFT NOT COINCIDING VERY WELL. BEST CHANCE ACCORDING TO THE SOUNDINGS WILL BE IN THE NORTHWEST PORTION OF THE AREA. WILL HAVE SCATTERED RAIN SHOWERS THROUGH THE NIGHT. MOST OF THE LIFT EXITS THE AREA SHORTLY AFTER 12Z. HOWEVER...COLD POOL ALOFT MOVES OVER THE AREA...AND SOUNDINGS BECOME MORE SATURATED. TQ INDEX VALUES SUPPORT INSTABILITY SHOWERS. WILL HAVE SLIGHT CHANCE TO CHANCE THROUGH THE DAY. ALSO WITH LITTLE DOWNWARD MOTION...MIXING/ENOUGH SUNSHINE...DO NOT BELIEVE THE WINDS WILL REACH WIND ADVISORY CRITERIA. WILL HAVE WINDY IN THE FORECAST. ALSO WITH CLOUDS AND COLD ADVECTION...WILL GO UNDERNEATH GUIDANCE. SATURDAY NIGHT/SUNDAY...SOME INSTABILITY SHOWERS WILL CONTINUE EARLY INTO THE EVENING THEN DRY. TEMPERATURES WILL RECOVER SOME BUT BELIEVE THE COOLER GUIDANCE WILL BE THE MOST REASONABLE. SUNDAY NIGHT/MONDAY...WARMUP WILL CONTINUE. BUT BELIEVE WITH A SHARPER UPPER RIDGE...MODELS MAY BE A LITTLE FAST IN WARMING THINGS UP. WILL GO NEAR TO SLIGHTLY BELOW GUIDANCE. FOR TUESDAY THROUGH FRIDAY...ONE PROBLEM AS OF THIS MORNING WITH THE MODELS IS THEY DO NOT LOOK SHARP ENOUGH WITH RIDGE AND TROUGH OVER THE CENTRAL PACIFIC. BASED ON WHAT SATELLITE IS SHOWING ME...RECENT PATTERN/BIASES...AND JET STRUCTURE...BELIEVE WILL HAVE A SHARPER AND FURTHER WEST UPPER RIDGE. BELIEVE THE LATEST GFS CAPTURES THIS THE BEST...AND WILL FOLLOW/BASE THE FORECAST OFF OF IT. NEW MODEL RUN CAME IN COOLER FOR WEDNESDAY AND THURSDAY. ALSO POPS HAVE RISEN INTO THE SLIGHT CHANCE TO LOW CHANCE CATEGORY FOR TUESDAY NIGHT AND WEDNESDAY NIGHT INTO THURSDAY. THINK THE GFS IS PRODUCING TOO HIGH OF POPS AND HOLDING ONTO THEM TOO LONG DESPITE ITS DOING BETTER WITH THE PATTERN. MAIN JET DYNAMICS LOOK TO STAY NORTH AND SOUTH OF THE AREA. ALSO AREA LOOKS TO BE IN CONFLUENCE ALOFT AS WELL. MOISTURE IS LACKING THROUGH MID LEVELS AND UPSLOPE IS NOT THAT STRONG. SO WILL BE KEEPING THIS PERIOD DRY...ALTHOUGH WOULD NOT BE SUPRISED TO SEE A FEW SPRINKLES/SHOWERS TUESDAY NIGHT AND WEDNESDAY MORNING AS STRONG FRONT PUSHES THROUGH. RAISED MAXES ON TUESDAY IN ADVANCE OF THE FRONT. BEHIND FRONT...MEX LOOKS TOO WARM BASED ON THE 850 MB TEMPERATURES. SO LOWERED MAXES ON WED AND THU. ALSO TWEEKED MINS DOWN A LITTLE AS WELL. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 934 PM EDT FRI SEP 22 2006 .UPDATE...ADIABATIC OMEGA ON THE 305K SURFACE DIMINISHING FROM WEST-EAST AS WEAK MID LEVEL VORT CENTER PUSHES EAST OF THE AREA. LOW CLOUD SATELLITE IMAGERY SHOWS DRIER AIR MOVING ACROSS LAKE MICHIGAN...WITH PARTIAL CLEARING NOW ENTERING MANISTEE COUNTY. BIG QUESTION OF THE NIGHT IS HOW TO HANDLE CLOUD TRENDS AND ISSUES OF STRATUS/FOG. TIME/HEIGHT CROSS SECTIONS AND RUC FORECAST SOUNDINGS SHOW SHALLOW MOISTURE /1000-950MB/ TRAPPED BENEATH A DEVELOPING INVERSION AFTER MIDNIGHT. LOOKING AT 950MB RH PROGS FROM THE ETA12 AND RUC...90%+ RH FIELDS STAY FROM I-75 EASTWARD OVERNIGHT...WITH AT LEAST SOME CLEARING FURTHER WEST. STRATUS DEVELOPMENT FURTHER DISRUPTED IN THE WEST BY VEERING 950MB FLOW AND 10-15KTS OF WIND NEAR THE LAKE SHORE. I WILL GO PARTLY CLOUDY WEST OF I-75 OVERNIGHT WITH CLOUDY EAST. I WILL MENTIONS AREAS OF FOG ALL AREAS. I WILL KEEP SCA/S UP FOR LAKE MICHIGAN NEARSHORE...AS VEERING LOW LEVEL FLOW TO SOUTHWEST WILL RESULT IN CONVERGENCE ALONG THE LAKE MICHIGAN SHORELINE AND LIKELY KEEP AT LEAST MARGINAL SCA CONDITIONS GOING. JK && .PREV DISCUSSION...ISSUED 318 PM FRI SEP 22 1ST BAND OF SHOWERS HAS LIFTED OUT OF EASTERN UPPER MI. 2ND BAND IS WORKING ACROSS NORTHERN LOWER MI FROM SW TO NE. BOTH BANDS SUFFERED FROM STILL DRY AIR BELOW 800MB...RESULTING IN ONLY SPOTTY AND LIGHT RAIN TO THIS POINT. SE LOW LEVEL WINDS ARE ACTING TO REINFORCE THE DRY LOW LEVELS. MORE SUBSTANTIAL PRECIP IS FALLING IN THE OHIO VALLEY. THIS IS ALL OCCURRING AHEAD OF A WELL-DEFINED AND NEARLY STACKED LOW NEAR SD/MN BORDER. PRECIP TRENDS ARE THE OBVIOUS MAIN CONCERN FOR TONIGHT. TONIGHT...RAIN BAND OVERHEAD APPEARS TO REPRESENT AN 850MB WARM FRONT (SURFACE WARM FRONT STILL WELL DOWNSTATE). 850MB FRONT WILL MOVE STEADILY NORTHWARD...CLEARING EASTERN UPPER MI THIS EVENING... WITH THE SURFACE BOUNDARY TRAILING SEVERAL FEW HOURS BEHIND. MAIN SYNOPTIC FOCUS FOR PRECIP WILL BE NORTH OF THIS BOUNDARY...AND AGAIN THE MAIN INHIBITING FACTOR THERE IS LOW LEVEL DRY AIR. WILL CARRY LIGHT SHOWERS LIKELY IN THE NE ZONES VERY EARLY ON TO ACCOUNT FOR THIS. IN THE WARM SECTOR...VERY LITTLE IS GOING ON AT THE MOMENT IN THE SOUTHERN LAKES. AS MENTIONED EARLIER...FOCUS OF THE LOW LEVEL JET WILL REMAIN WELL TO THE SOUTH...FROM THE LOW/MID OHIO VALLEY TOWARD LAKE ERIE...WITH ANOTHER SURGE POINTING TOWARD CENTRAL IL LATE. THERE IS SOME 300MB DIVERGENCE IN LEFT EXIT REGION OF 120KT JET EJECTING INTO THE SOUTHERN LAKES...BUT IN GENERAL IT LOOKS RATHER UNFOCUSED...AND WILL DIMINISH LATE AS JET CORE HEAD EAST. 700-500MB LAPSE RATES NEAR 6.5C/KM...KINDA STEEPISH BUT AGAIN NOT REALLY IMPRESSIVE. SO NOT A LOT OF FORCING TO GENERATE PRECIP. BUT AS CONVECTIVE ELEMENTS LIFT NE FROM THE MID MS VALLEY...THERE IS ENOUGH SUPPORT TO ALLOW THEM TO HOLD TOGETHER TO SOME DEGREE. SO UNTIL CONVECTIVE EVOLUTION UPSTREAM REVEALS ITSELF MORE FULLY...HARD TO IDENTIFY WHO WILL GET WET AND WHO WON/T. PLACES NEAR SAGINAW BAY SHOULD HAVE A BETTER CHANCE OF SEEING SHOWERS LIFT NORTH...WITH THE DYNAMIC FOCUS OFF TO THE SE...AND WITH THE EXPECTED ENE/NE PROPAGATION OF STORMS IN MO. THIS SHOULD ALSO BE THE AREA WITH THE BEST CHANCE OF THUNDER. MARINE...STILL BREEZY OUR THERE...AND SMALL CRAFTS WILL CONTINUE THRU THE EVENING. PRESSURE GRADIENT RELAXES AS SURFACE LOW IN MN FILLS DURING THE NIGHT. HOWEVER...AS LOW LEVEL WINDS VEER SSW COASTAL CONVERGENCE AND THE LONG FETCH WILL COME INTO PLAY ON LAKE MI. WILL EXTEND SCA THRU THE NIGHT ON LAKE MI WATERS. ZOLTOWSKI REMAINDER OF THE FORECAST (SATURDAY THROUGH NEXT FRIDAY)...LOTS OF QUESTIONS OVER THE NEXT 48 HOURS ABOUT THE EVOLUTION OF THE STORM SYSTEM CURRENTLY CENTERED ACROSS THE NORTH CENTRAL PLAINS. BEHIND THAT A BREAK IN THE ACTION IS EXPECTED EARLY NEXT WEEK BEFORE ANOTHER TROUGH AFFECTS THE REGION DURING THE MIDDLE AND END OF NEXT WEEK. THE MAIN FORECAST CONCERNS WILL REVOLVE AROUND THE DETAILS OF THE SYSTEM THIS WEEKEND WITH AMOUNT OF CONVECTION ON SATURDAY THE MOST PRESSING ISSUE. SATURDAY...MODEL SOLUTIONS DIFFER ON THE EVOLUTION OF UPPER AND LOWER LEVEL SYSTEMS. AT THIS POINT WILL TAKE A COMPROMISE SOLUTION WITH THE NAM TO START AS THE GFS SEEMS TO BE SUFFERING FROM SOME CONVECTIVE FEEDBACK ISSUES BUT LEAN TOWARD THE FASTER TIMING OF THE GFS/ECMWF SATURDAY NIGHT INTO SUNDAY. IN A NUTSHELL...UPPER LEVEL SYSTEM CONTINUES TO MEANDER NORTH NORTHWEST THROUGH SATURDAY EVENING WHILE DRAGGING A COLD FRONT ACROSS THE REGION LATE SATURDAY OR SATURDAY EVENING. MID LEVEL DRY SLOT IS EXPECTED TO BE ACROSS THE REGION IN THE MORNING SO ITS HARD TO SAY JUST HOW MUCH SUNSHINE THERE WILL BE. THIS WILL OBVIOUSLY IMPACT POTENTIAL INSTABILITY AS TEMPERATURES RISE TO NEAR 70 OR SO. AT THIS POINT EXPECT A CHANCE OF SHOWERS IN THE MORNING BEFORE DEEPER MOISTURE (MEAN 1000-500 MB RH INCREASES FROM 60 TO 70 PERCENT TO 80 TO 90 PERCENT) AND BETTER DYNAMICS ENCROACH THE REGION FROM THE SOUTH IN THE AFTERNOON. AS FAR AS SEVERE POTENTIAL GOES...WIND FIELDS ARE FAIRLY STRONG WITH 130 KNOT JET NEARLY OVERHEAD BUT OTHERWISE...THETA-E RIDGE AND HIGHER SURFACE DEWPOINTS REMAIN TO OUR SOUTH. WILL BRING IN LIKELY POPS AND A CHANCE OF TSTORMS ACROSS SOUTHERN COUNTIES IN THE AFTERNOON AND A CHANCE OF SHOWERS AND SLIGHT CHANCE OF STORMS NORTH. SATURDAY NIGHT AND SUNDAY...AS STATED ABOVE WILL FOLLOW THE NAM BUT SPEED UP THE TIMING SO EXPECT SURFACE COLD FRONT TO MOVE THROUGH IN THE EVENING WITH ABUNDANT WRAP AROUND MOISTURE TO FOLLOW AS SURFACE AND UPPER LEVEL WAVES TAKE THEIR TIME MOVING ACROSS THE REGION. HAVE INCREASED QPF WITH UPWARDS OF A HALF INCH PLUS EXPECTED (SHOWERS) AND UPPED POPS TO LIKELY SATURDAY NIGHT INTO SUNDAY MORNING THEN BACK THEM DOWN TO CHANCE SUNDAY AFTERNOON DUE TO TIMING UNCERTAINTY (GFS WOULD END ACTIVITY MUCH FASTER WHILE THE NAM WOULD LINGER SHOWERS INTO SUNDAY AFTERNOON). IT WILL TURN BRISK AND COOLER DURING THE DAY ON SUNDAY AS WELL WITH TEMPERATURES GENERALLY HOLDING IN THE 50S. MONDAY AND TUESDAY...A NICE BREAK IN THE ACTION COURTESY OF INCREASING SHORT WAVE RIDGING AT THE SURFACE AND ALOFT OUT AHEAD OF ANOTHER SYSTEM DUE IN FOR MIDWEEK. PARTLY CLOUDY CONDITIONS EXPECTED WITH HIGHS GENERALLY IN THE 60S WITH LOWS IN THE UPPER 30S AND 40S. WEDNESDAY...A FAIRLY POTENT UPPER TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH THE REGION BRINGING MORE CHANCES FOR SHOWERS AND EVEN THUNDERSTORMS. HAVE INCREASED POPS INTO THE HIGH CHANCE CATEGORY. THE EXACT TIMING OF THE FRONT WILL DETERMINE HOW WARM IT WILL GET BUT WILL STICK WITH HIGHS RANGING FROM AROUND 60 NORTHWEST TO NEAR 70 SOUTHEAST (COULD EVEN END UP SEEING FALLING TEMPERATURES IN THE AFTERNOON). THURSDAY AND FRIDAY...COLD UPPER TROUGH RESIDES OVER THE REGION LEADING TO POSSIBLE LAKE EFFECT RAIN SHOWERS FOR AT LEAST THURSDAY INTO EARLY THURSDAY NIGHT. DRIER AIR IS THEN SHOWN TO ADVECT INTO THE REGION WHICH MAY SPELL A FROST OR FREEZE FOR FRIDAY MORNING. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S WITH A CHILLY NORTHWEST WIND BOTH DAYS. SULLIVAN && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 419 PM EDT FRI SEP 22 2006 .DISCUSSION... MAIN FCST CONCERNS ARE PCPN TRENDS THRU SUN. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A BROAD TROF DOMINATING THE W HALF OF THE CONUS. A CLOSED MIDLEVEL LOW WAS LOCATED ALONG THE SD/MN BORDER WHILE A WELL-DEFINED SHORTWAVE WAS OVER UT/CO. SHRA HAVE BEEN LIFTING N INTO THE UPPER GREAT LAKES TODAY WITH BULK OF PCPN OCCURRING ALONG AND AHEAD OF NORTHWARD MOVING 850MB WARM FRONT ANALYZED FROM SRN MN THRU E CNTRL WI AT 12Z. CURRENTLY RUC ANALYSIS SHOWS MDT/STRONG MOIST ISENTROPIC ASCENT ON THE 300K SFC SPREADING ACROSS UPPER MI. AT THE SFC...OCCLUDED SFC LOW WAS LOCATED ALONG SD/MN BORDER. MODEL DISAGREEMENT CONTINUES (NAM VS THE REST OF THE MODELS) WITH REGARD TO FUTURE SFC RESPONSE AS SHORTWAVE CURRENTLY OVER CO/UT MOVES ACROSS THE PLAINS TOWARD THE GREAT LAKES. NAM HAS BEEN AND CONTINUES TO BE MUCH STRONGER AND FARTHER NW WITH THE NEW SFC LOW PRES DEVELOPING IN RESPONSE TO SHORTWAVE. HOWEVER...IT IS TRENDING A LITTLE WEAKER AND FARTHER S AND E WITH LOW AS IT MOVES INTO THE GREAT LAKES. THUS...IT IS AT LEAST TRENDING TOWARD THE CONSENSUS SOLUTION OF OTHER MODELS (SFC LOW TRACKING THRU SRN LWR MI SAT EVENING). COMBINATION OF NAM/GFS WILL BE UTILIZED THRU 12Z SAT... THEN GFS/CANADIAN/UKMET THEREAFTER AS THOSE MODELS HAVE BEEN RELATIVELY CONSISTENT ON EVOLUTION OF SHORTWAVE AND SFC FEATURES. 850MB WARM FRONT WILL LIFT N ACROSS UPPER MI THIS EVENING AND STALL OUT ACROSS NRN/WRN LAKE SUPERIOR. AS IT DOES SO...ISENTROPIC ASCENT (300K SFC) DIMINISHES TO ALMOST NOTHING. THUS...BAND OF SHRA CURRENTLY LIFTING THRU NRN WI/UPPER MI SHOULD LIFT MOSTLY N OF UPPER MI BY MIDNIGHT. KEWEENAW/FAR W WILL HAVE A BETTER CHC OF SEEING SHRA THRU THE NIGHT WITH CLOSE PROXIMITY OF 850MB FRONT. MEANWHILE...LEFT EXIT OF UPPER JET MOVING THRU LWR MI MAY ALSO SPARK A FEW ADDITIONAL SHRA AND MAYBE A TSRA OR TWO ACROSS SE UPPER MI...BUT EVEN THAT FORCING SHIFTS TO THE NE OVERNIGHT. OTHERWISE...FCST WILL SHOW DIMINISHING POPS THRU THE NIGHT. GFS FCST SOUNDINGS HINT AT ENOUGH MIDLEVEL DRYING FOR POSSIBLE -DZ. LOW LEVEL MOISTURE ADVECTION AND MOISTENING FROM EARLIER RAINFALL WILL ALSO AID FOG FORMATION. PCPN DURING THE FIRST HALF OF SAT SHOULD BE CONFINED TO MAINLY THE NW PART OF UPPER MI IN THE VCNTY OF 850MB FRONT. THEN...AS SHORTWAVE CURRENTLY OVER CO/UT MOVES INTO THE MIDWEST SAT AFTN... FAIRLY STRONG MID/UPPER LEVEL QVECTOR CONVERGENCE DEVELOPS. THIS OVERLAYS STRENGTHENING LOW-LEVEL FRONTOGENESIS. END RESULT OF THIS COUPLED LOW AND UPPER FORCING SHOULD BE A RAPIDLY DEVELOPING/EXPANDING AREA OF RAIN INTO UPPER MI DURING THE AFTN/EVENING. PREVIOUS FCST REFLECTED THIS SCENARIO WELL...SO FEW CHANGES WERE NEEDED OTHER THAN BUMPING UP POPS SLIGHTLY AS THERE IS INCREASED CONFIDENCE OF RAIN DEVELOPING. ONLY EXCEPTION IS THE KEWEENAW WHERE CHC POPS WERE KEPT AS MAIN FORCING SHOULD PASS SE OF THAT AREA. RAIN WILL DIMINISH AND THEN END FROM NW TO SE LATER SAT NIGHT/SUN MORNING AS SYSTEM PULLS AWAY. ANOTHER SHORTWAVE IS STILL PROGGED TO SWIPE THE UPPER LAKES REGION SUN NIGHT/MON MORNING...POTENTIALLY BRINGING A FEW SHRA TO ERN LAKE SUPERIOR AND ERN UPPER MI. TUE THRU FRI...THIS PORTION OF THE FCST IS FAIRLY STRAIGHT FORWARD TODAY AS THE ECMWF/CANADIAN/UKMET/GFS ARE IN GOOD AGREEMENT. THE ONLY FEATURE OF SIGNIFICANT INTEREST IS A STRONG SHORTWAVE PASSING THRU THE UPPER LAKES EARLY IN THE PERIOD WITH SUBSEQUENT PROGRESSIVE TROF AMPLIFICATION FROM THE GREAT LAKES TO THE E COAST. SURPRISINGLY...FOR HOW FAR OUT IN THE MODEL RUNS THIS SYSTEM IS... THE MODELS SHOW ONLY MINOR TIMING ISSUES (ALL SHOW FROPA OCCURRING ROUGHLY TUE NIGHT). DEPENDING ON EXACT TIMING OF FRONT...TUE SHOULD BE A WARM DAY WITH 850MB THERMAL RIDGE OF 10C OR POSSIBLY HIGHER SHIFTING NE ACROSS UPPER MI. FOR NOW...WILL ASSUME FRONT WILL BE SLOW ENOUGH TO MAXIMIZE WARMTH. PREVIOUS FCST HIGHS IN THE UPPER 60S/AROUND 70 LOOK ON TRACK. WILL CARRY CHC -SHRA ALONG/JUST AHEAD OF FRONT TUE NIGHT. IT WILL TURN MUCH COOLER WED/THU WITH 850MB TEMPS DROPPING TOWARD -2C...SUFFICIENT FOR SCT LAKE EFFECT RAIN SHOWERS. COVERAGE WILL DEPEND ON SYNOPTIC SUPPORT...EITHER THRU PASSAGE OF ANY WEAK SHORTWAVES OR DEEPER MOISTURE (BOTH OF WHICH ARE UNCERTAIN). SO LOW END CHC POPS WILL BE UTILIZED FOR NOW. ANY LINGERING LAKE EFFECT -SHRA SHOULD END EARLY FRI WITH HIGH PRES BUILDING INTO THE WRN LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1040 AM EDT FRI SEP 22 2006 .UPDATE...MOISTENING PROCESS CONTINUES OVER THE FORECAST AREA THIS MORNING...AS INITIAL BAND OF LIGHT PRECIP (MAINLY SPRINKLES) LIFTS NWD INTO ERN UPPER. 1200 UTC APX/GRB/DTX SOUNDINGS REVEAL CONSIDERABLE DRY AIR BELOW ABOUT 10 KFT...PER EARLIER DISCUSSION. THIS DRY AIR WILL HAVE TO BE OVERCOME BEFORE MORE WIDESPREAD RAIN CAN OCCUR (FOR SOME AREAS...THIS MAY BE DELAYED INTO THIS EVENING). TIMING OF MORE SUBSTANTIAL RAIN CONTINUES TO BE MAIN CONCERN FOR THE AFTERNOON. NEXT BATCH OF RAIN WITH EMBEDDED THUNDER WAS LIFTING NE THROUGH CENTRAL/SOUTHERN LAKE MICHIGAN. 850 MB ANALYSIS SHOWED 50 KT LLJ WITH NARROW RIBBON OF +11C DEW POINTS OVER ILLINOIS...WHICH WAS FUELING THE SHOWERS. ADDITIONAL SUPPORT WAS BEING PROVIDED BY LEFT EXIT FORCING (DIVERGENCE ALOFT) FROM 500-300 MB JETS PUNCHING ENE ACROSS MO AND NRN IL. THIS AFTERNOON...NAM/RUC SUGGEST THAT LLJ OVER IL WILL WEAKEN -- AS WEAKER 850 MB JET ENERGY SHIFTS TO WI WITH ANOTHER BRANCH OVER OH VALLEY. SIMILARLY...LATEST 1200 UTC SHORT RANGE MODEL OUTPUT SUPPORTS BEST LARGE-SCALE ASCENT OVER WI THIS AFTERNOON -- AND THIS IS WHERE MOST WIDESPREAD RAIN SHOULD OCCUR. OVERALL CHANGES FROM GOING FORECAST MINOR. HOWEVER...HAVE TRIMMED RAIN CHANCES SLIGHTLY OVER ERN AREAS. BASED ON EXTRAPOLATION...WILL KEEP RAIN LIKELY OVER AREAS W OF I-75 THIS AFTERNOON. WITH DECREASING JET SUPPORT...WILL NOT INCLUDE THUNDER. WITH BEST LIFT FOCUSED TO OUR WEST...AND AFOREMENTIONED DRY AIR...WILL OPT FOR ONLY SCATTERED SPRINKLES THIS AFTERNOON FOR FAR ERN AREAS...INCLUDING APN AND VICINITY. APPEARS THAT STEADIER RAIN WILL LIKELY HOLD OFF FOR AREAS ALONG AND E OF I-75 UNTIL (POSSIBLY WELL INTO) THIS EVENING. AFTERNOON HIGHS WILL RANGE FROM AROUND 60 TO THE MID 60S...PER GOING FORECAST. SMITH && .PREV DISCUSSION...ISSUED 500 AM FRI SEP 22 SFC/RUC/SATELLITE/RADAR AND UPPER AIR ANALYSIS SHOWING WELL DEFINED UPPER/SFC LOWS SPINNING OVER THE NEBRASKA/IOWA BORDER AND HEADING NORTH. INITIAL VORTICITY LOBE AND BAND OF DEEPER MOISTURE TRAPPED MORE SO IN THE MID LEVELS IS WORKING NORTHWARD AND SCRAPING THE SRN AND WESTERN PORTIONS OF THE CWA. RADAR SUGGESTING THAT SPRINKLES OR LIGHT RAIN IS ALL THAT CAN OCCUR AS AIR MASS WAS RATHER DRY INITIALLY PER 00Z APX SOUNDING (0.42"). WINDS WERE BELOW 10KT FROM THE SE AND TEMPERATURES RANGED FROM THE UPPER 30S TO MIDDLE 50S. FORECAST CONCERNS...MANY. MARINE ISSUES TODAY AND THIS EVENING WITH WINDS/WAVES UNDER STRENGTHENING SE FLOW. TOUGHEST ISSUE TO TACKLE IS THE CHANCE FOR PRECIPITATION THROUGH THE WEEKEND...ALONG WITH THE CHANCE FOR THUNDER. SFC LOW WILL FILL/WEAKEN TODAY...THEN A NEW SFC LOW DEVELOPS AS UPPER TROUGH LIFTS OUT OF THE MISSISSIPPI VALLEY AND INDUCES CYCLOGENESIS IN ILLINOIS SATURDAY. THIS NEW LOW WILL RIDE UP THROUGH CENTRAL LOWER MICHIGAN. EXACT TRACK/STRENGTH OF THIS LOW REMAINS SOMEWHAT IN QUESTION AND MODELS CONTINUE TO HAVE A DIFFICULT TIME IN DEALING WITH SOME OF THE FINER DETAILS. TODAY...DEEP/FILLING SFC LOW WILL TRACK NORTHWARD TODAY AND THE PRESSURE GRADIENT ACROSS NRN MICHIGAN WILL TIGHTEN INTO THIS EVENING...MAINLY FOR THE WESTERN PORTIONS OF THE CWA. 950-850MB WINDS INCREASE TO 25-30KTS WITH MIXING OVER LAND EXPECTED TO TAP INTO RIGHT AROUND 25 KNOTS RESULTING IN OFF SHORE GUSTS AT SMALL CRAFT ADVISORY LEVELS. LOCAL EFFECTS AND LONGER FETCHES ACROSS THE LAKE HURON SHORELINE WILL LEAD TO SOME GUSTS TO 25 KNOTS AND WAVES NEARING 3 TO 5 FEET BY LATER THIS AFTERNOON. THEREFORE...HAVE HOISTED SMALL CRAFT ADVISORIES FOR ALL AREAS EXCEPT ST. MARY'S RIVER (WHERE WEAKEST OF WINDS SHOULD RESIDE). OBSERVATIONS SHOWING THAT RAIN IN A VERY LIGHT FORM HAS MADE IT DOWN TO THE SFC FOR THE SW CWA ASSOCIATED WITH VORT LOBE/305-315K ISENTROPIC ASCENT AND NICE H4-H2 LAYER DIVERGENCE...SO WILL GO WITH LIKELY LIGHT RAIN THIS MORNING FOR THE GTV BAY REGION...AS FAR EAST AS HOUGHTON LAKE. THIS VORT LOBE SWINGS THROUGH THE NORTHERN CWA EARLY THIS MORNING...BUT AIR MASS IS LIKELY TOO DRY FURTHER NE FOR MUCH OF NE LOWER TO SEE ANY OF THIS LIGHT RAIN AT THE SFC...SO WILL KEEP THINGS DRY THERE FOR THE MORNING HOURS. HOWEVER...ADDITIONAL SHORTWAVE ENERGY/LAYER ISENTROPIC ASCENT (305-315K)/INCREASED 850-700MB FRONTOGENESIS SWINGS INTO THE CWA THIS AFTERNOON...AND WITH INITIAL WAVE MOISTENING THE ATMOSPHERE UP...THIS ROUND OF PRECIP SHOULD MORE EFFICIENTLY REACH THE SFC. HAVE GONE WITH LIKELY CHANCES FOR LIGHT RAIN FOR ALL BUT NE LOWER WHERE THE DRIEST OF AIR WILL RESIDE. CHANCES ARE CERTAINLY THERE THOUGH. RAINFALL AMOUNTS SHOULD BE RATHER SMALL/LIGHT WITH MOST AREAS SEEING ONLY A FEW HUNDREDTHS. TONIGHT...SFC LOW CONTINUES TO FILL AND THE PRESSURE GRADIENT RELAXES IN THE EVENING...BUT NOT AFTER A FEW 25 KNOT GUSTS HOLD ON INTO THE EARLY EVENING. THE FRONTOGENESIS/DEEPER H8-H5 LAYER -DIVQ EXITS NORTH OF EASTERN UPPER BY MID EVENING...ONLY TO BE REPLACED BY LEFT EXIT REGION OF 130KT JET/ANOTHER ROUND OF H4-H2 LAYER DIVERGENCE AND MID LEVEL LAPSE RATES TO 6.5C/KM. STRONGEST DYNAMICS LOOKS TO BE ACROSS NRN LOWER AND HAVE BUMPED CHANCES FOR PRECIPITATION TO LIKELY...AND ADDED CHANCES FOR THUNDER DUE TO THE STEEPER LAPSE RATES. LLJ LOOKS TO BE PRETTY FAR TO THE SE OF THE AREA BUT EXACT EVOLUTION OF THIS SYSTEM REMAINS UNCLEAR TO SOME DEGREE. TEMPERATURES ARE LIKELY TO NOT FALL OUT OF THE 50S ANYWHERE. SATURDAY AND SATURDAY NIGHT...LOW LEVEL JET AND UPPER AIR DYNAMICS WORK WELL EAST OF US SATURDAY MORNING...AND MID LEVEL DRYING SEEMS TO WANT TO MOVE IN. JUST WENT WITH CHANCES FOR SHOWERS...AND WOULD HAVE THOUGHT ABOUT GOING DRY FOR THIS TIME PERIOD IF IT WASN'T FOR THE UNCERTAINTY IN THE MODELS. SATURDAY AFTERNOON...UPPER TROUGH LIFTS NE AND NEXT SFC LOW DEVELOPS IN THE ILLINOIS VICINITY...WHICH IS FORECAST TO RIDE UP THROUGH CENTRAL LOWER SATURDAY NIGHT. NEXT UPPER LEVEL JETLET AND LLJ JET MOVE IN/DEVELOP MAINLY AROUND 06Z IN THE SAGINAW BAY AREA. STRONG H8-H5 -DIVQ FINDS ITS WAY INTO THE SRN STRETCHES OF NRN MICHIGAN LATE IN THE AFTERNOON...BUT REALLY HOLD OFF UNTIL MAINLY SATURDAY NIGHT. WILL KEEP THINGS ON THE CHANCE SIDE FOR NOW...AND BRING IN THE LIKELY CHANCES FOR PRECIPITATION SATURDAY NIGHT. SFC LOW TRACK WILL BE KEY...CURRENT IDEA IS FOR A FAR ENOUGH SOUTH TRACK FOR THUNDERSTORMS...FIRED OFF ALONG LEADING EDGE OF DRY SLOT...TO BE JUST TO OUR SE MORE IN SRN LOWER. HOWEVER...DID NOT VEER FROM ONGOING FORECAST OF THUNDER CHANCES ACROSS NRN LOWER AS DYNAMICS ALONE WILL BE RATHER STRONG. DO NOT EVEN THINK I COULD RULE OUT THUNDER FOR EASTERN UPPER TOO...BUT WILL WAIT FOR SOME OF THE DETAILS TO COME MORE INTO FOCUS. ALSO HAVE TO WATCH FOR DEEPER MOISTURE WRAPPED ON NW FLANK OF UPPER TROUGH...WHICH COULD PROVIDE SOME DECENT RAINFALL AMOUNTS SATURDAY NIGHT. AGAIN...UNCERTAINTIES IN EVOLUTION OF THIS SYSTEM PREVENT FROM GETTING TOO SPECIFIC WITH THE FORECAST ATTM. SUNDAY...NO REAL CHANGES...BUT WILL KEEP CHANCES FOR SHOWERS AS WRAP-AROUND MOISTURE WILL SWING IN ACROSS THE CWA...WITH BRISK NW WINDS DEVELOPING WITH THE PASSAGE OF THE COLD FRONT. SMALL CRAFT ADVISORIES LOOK LIKE A GOOD BET BY SUNDAY AFTERNOON. SMD && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 310 PM CDT FRI SEP 22 2006 .DISCUSSION... CONCERN IN THE VERY SHORT TERM IS POTENTIAL THUNDERSTORM DEVELOPMENT OVER THE NEXT FEW HOURS JUST SE OF OUR CWA. RUC CONVECTIVE PARAMETERS SHOW THAT IF THUNDERSTORMS DO DEVELOP THEY WOULD BE TO THE SOUTHEAST OF KEAU BETWEEN 21Z AND 00Z. WHAT MAKES THIS AREA EXPLOSIVE IS THE LEFT EXIT REGION OF A 120 KNOT JET POKING INTO THE AREA. DRY SLOT AND SUNSHINE/WARMER AIR IS MAKING SLOW PROGRESSION INTO SW WISCONSIN ATTM. PLAN IS TO LEAVE CONVECTION OUT OF THE WI CWA. EVENING CREW WILL NEED TO MONITOR. OVERNIGHT AND SATURDAY STILL ON TRACK FOR RAIN. AGREEMENT IN THE GFS/NAM-WRF HOLDS INTO MIDDAY SATURDAY AND THEN THE GFS BEGINS TO ACCELERATE THE UPPER AIR SYSTEM TO THE EAST QUICKER THAN THE NAM- WRF. 250MB JET PROGS FROM THE TWO SOLUTIONS ARE SIMILAR SATURDAY AND SATURDAY NIGHT AND THE DPROG/DT ON THE GFS HAD BETTER RUN TO RUN CONSISTENCY. THEREFORE...FOLLOWED THE GFS SATURDAY NIGHT AND SUNDAY WHICH ENDS THE PRECIPITATION OVER THE WESTERN CWA DURING THE FIRST HALF OF THE NIGHT AND OVER THE FAR EASTERN CWA BY SUNDAY MORNING. GOOD FORCING SEEN OVER MUCH OF THE CWA TONIGHT AND SATURDAY. 600-700MB FWF STRENGTHENS OVER EASTERN MN AND WEST WI TONIGHT AND PERSISTS INTO SATURDAY AFTERNOON. A GOOD RESPONSE SEEN IN THE -FN VECTOR DIVERGENCE. A COUPLED JET ALSO COMES INTO THE PICTURE DURING THE DAY TOMORROW OVER THE EASTERN CWA WITH SUBSTANTIAL LAYER DIVERGENCE PROGGED. THROUGHOUT TONIGHT AND MUCH OF SATURDAY THERE IS UPGLIDE AND ISENTROPIC OMEGA SEEN ON THE 300K THETA SURFACE. SO LIKELY TO CATEGORICAL POPS USED FOR MUCH OF THE AREA TONIGHT AND SATURDAY. BETTER CONDITIONS FOR SUNDAY WITH A BREEZY AFTERNOON IN STORE AS HIGH PRESSURE BUILDS IN FROM THE WEST. LOW LEVEL WAA BEGINS SUNDAY NIGHT. THIS IS A LITTLE TROUBLESOME AS SOME HINTS IN LOW/MID LEVEL CLOUDINESS MAY BE ON THE INCREASE...ESPECIALLY ON MONDAY. THEREFORE...KEPT HIGHS ON MONDAY IN THE 65 TO 70 DEGREE RANGE. LONGER TERM...MONDAY NIGHT THROUGH FRIDAY MILD TEMPERATURES START THE PERIOD WITH H5 TROF DIVING DOWN ACROSS SRN CANADA WITH ASSOCIATED COLD FRONT ACROSS THE ERN DAKOTAS BY TUESDAY AFTERNOON. MOISTURE LOOKS TO BE ON THE LOW END OF THE SPECTRUM FOR THIS SYSTEM BUT STILL EXPECT AT LEAST SOME SHOWER AND THUNDERSTORM ACTIVITY TUESDAY EVENING INTO WEDNESDAY MORNING. UPPER TROF LAGS THE FRONT AND CROSSES THE AREA EARLY THURSDAY. TEMPERATURES EXPECTED TO BE IN THE LOW 70S TUESDAY WITH +10 TO +14 CELSIUS H85 TEMPS THEN FALLING TO AROUND 0 C FOR WEDNESDAY. WITH CENTER OF UPPER LOW TRACKING WELL TO THE NORTHEAST OF THE LOCAL AREA...WRAP AROUND MOISTURE WILL BE LIMITED THUS EXPECT SOME SUNSHINE AND TEMPS THAT MAY MODERATE MORE THAN WE HAVE SEEN WITH RECENT SYSTEMS AS A RESULT...WITH HIGHS IN THE UPPER 50S TO AROUND 60 WEDNESDAY THROUGH FRIDAY. WAA RETURNS FROM WEST TO EAST FRIDAY BUT LOOKS TO BE BRIEF AS GFS AND ECMWF BRING ANOTHER TROF ACROSS SRN CANADA AS STRONG UPPER JET DIGS INTO THE NORTHERN PLAINS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RAH/MDB mn AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 329 PM CDT FRI SEP 22 2006 .DISCUSSION... FOCUS TURNS FROM CONCERNS OF AFTERNOON SEVERE WEATHER TO WHETHER THERE WILL BE ANY WEATHER OVERNIGHT. A WELL STACKED UPPER LEVEL LOW IS STILL LOCATED OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A SHORTWAVE DIVING UNDER ITS SOUTHWEST SIDE THROUGH WESTERN COLORADO. THE SURFACE FRONT EXTENDING FROM THE LOW SNAKES DOWN THROUGH THE IOWA/ILLINOIS/MISSOURI TRIPLE POINT...TO COLUMBIA...AND INTO THE VICINITY OF JOPLIN BEFORE HEADING WEST TO A SECONDARY SURFACE LOW IN THE PANHANDLE OF TEXAS. FOR THE REST OF THE AFTERNOON AND INTO THE FIRST HALF OF THE OVERNIGHT HOURS...THE STRONGEST H8 WINDS AND BEST 0-3KM SHEAR WILL REMAIN FOCUSED SOUTH OF THE FRONT ACROSS THE SOUTHERN HALF OF MISSOURI. THIS ALSO APPLIES TO THE MOISTURE FIELDS. THE UPSHOT FOR OUR FORECAST AREA IS THAT THUNDERSTORM CHANCES ARE ALMOST NONEXISTENT FOR THE REST OF THE AFTERNOON AND EVENING HOURS. HAVE TRIMMED POPS TO SLIGHT CHANCES THROUGH MIDNIGHT AS A RESULT. BEFORE MIDNIGHT THE 12Z MODELS ARE IN FAIRLY GOOD AGREEMENT ON KEEPING MUCH...IF NOT ALL...OF THE FORECAST AREA DRY. DIFFERENCES START TO POP UP AFTER MIDNIGHT AS THE GFS AND WRF BEGIN TO DIVERGE ON HOW TO HANDLE THE FRONT. THE WRF BRINGS THE FRONT NORTH SOME 60 TO 80 MILES EARLY SATURDAY MORNING AS THE SURFACE WAVE MOVES ALONG THE FRONT. IN CONTRAST THE GFS HOLDS THE FRONT ALONG OUR SOUTHEAST EDGE...EFFECTIVELY ONLY MOVING IT NORTH SOME 30 MILES. WRF APPEARS TO BE EMPHASIZING THE SECONDARY SHORTWAVE DIVING THROUGH COLORADO A BIT TOO MUCH. THIS HAS THE EFFECT OF PULLING THE CENTER OF THE MAIN LOW BACK TO THE SOUTHWEST INTO EASTERN NEBRASKA...WHICH THEN LIFTS THE FRONT NORTH IN MISSOURI. PREFERENCE IS FOR THE GFS WHICH KEEPS THE CENTER OF THE WELL STACKED LOW IN SOUTHEASTERN SOUTH DAKOTA. UKMET/ECMWF/UKMET AND THE 18Z WRF BACK THIS IDEA UP. WITH EXPECTATIONS THAT THE FRONT WILL STAY CONFINED TO OUR SOUTHEAST EDGE I HAVE KEPT THE FOCUS FOR THUNDERSTORM ACTIVITY CONFINED TO AREAS FROM CLINTON MISSOURI NORTHEAST THROUGH SEDALIA AND MOBERLY FOR TOMORROW MORNING. FARTHER NORTHWEST...FOR THE HOURS BEFORE AND AFTER SUNRISE...SOME SHOWERS AND ISOLATED THUNDER LOOK POSSIBLE. BY TOMORROW AFTERNOON ENOUGH COOL DRY AIR WILL HAVE MOVED INTO THE AREA TO FORCE ALL OF THE CONVECTIVE ACTIVITY TO OUR EAST. HAVE KEPT SOME TOKEN CHANCE SHOWERS IN NORTHEAST MISSOURI FOR WRAP AROUND SHOWER ACTIVITY UNDER THE LOW. CUTTER GFS AND ECMWF ARE NOW REMARKABLY SIMILAR WITH THE MID WEEK ARRIVAL OF A STRONG COLD FRONT. BOTH MODELS ADVERTISE A PATTERN CHANGE AS A STRONG MID/UPPER LEVEL TROUGH DEEPENS AS IT DROPS SOUTHEAST FROM CENTRAL CANADA. TIMING IS ALSO VERY SIMILAR WITH THE COLD FRONT MOVING INTO NORTHERN MO BY 12Z WEDNESDAY WITH STRONG COLD AIR ADVECTION LAGGING BEHIND...ARRIVING WEDNESDAY NIGHT. EARLIER ECMWF DID NOT HAVE AS MUCH COLD AIR COMING DOWN BUT NOW IS ON THE SAME PAGE AS THE GFS AS BOTH MODELS FORECAST THE 0C LINE AT 850MB REACHING THE MO/IA STATE LINE BY 12Z THURSDAY. CURRENT FORECAST WENT A TAD COOLER THAN PREVIOUS FORECASTS BUT MAY NOT BE COLD ENOUGH GIVEN EXPECTED 850MB TEMPERATURES BUT FORECAST TRIED TO BLEND IN WITH SURROUNDING OFFICES. POST FRONTAL PRECIPITATION POSSIBLE WITH THE CONVERGENCE MORE TIED TO THE 850MB FRONT AS THE GULF LOOKS LIKE IT WILL BE CLOSED OFF DUE TO THE PREVIOUS FRONT CLEANING OUT THE DEEPER LOW LEVEL MOISTURE. PRIOR TO THE ARRIVAL OF THE MID WEEK COOL DOWN THERE SHOULD BE A TWO DAY WINDOW OF INCREASING WARM AIR ADVECTION WITH TUESDAY HIGH TEMPERATURES GOING ABOVE SEASONAL VALUES BY 1 TO 2 CATEGORIES. MJ && .PREVIOUS DISCUSSION... 1222 PM... FOCUS IS ON THE POTENTIAL FOR SEVERE WEATHER LATER THIS AFTERNOON. THE UPPER LEVEL LOW IS IN EASTERN SOUTH DAKOTA AT THIS HOUR WITH A SHORTWAVE WAVE DIVING DOWN ITS SOUTHWEST SIDE ACROSS WESTERN COLORADO. CLOSER TO HOME A FRONT EXTENDS FROM NORTHEAST MISSOURI TO JUST NORTH OF JOPLIN...SKATING THE SOUTHEAST EDGE OF THE CWA. SHEAR ACROSS THE FRONT IS QUIT HIGH WITH THE LATEST RUC ANALYSIS SHOWING 0-3KM SHEAR AROUND 45-50 KTS. HOWEVER...SATELLITE IMAGERY AND SURFACE DEW POINTS SHOW THE BETTER SURFACE AND ELEVATED MOISTURE LOCATED SOUTH OF THE FRONT. CLOUDS ACROSS SOUTHERN MISSOURI ON VISIBLE SATELLITE IMAGERY LOOK TO SHOW THE EXPECTED LOCATION OF THIS AFTERNOONS EXPECTED ACTIVITY...BASICALLY ALONG AND SOUTH OF A LINE FROM PITTSBURG KANSAS NORTHEAST THROUGH COLUMBIA MISSOURI. STILL... THERE IS THE POTENTIAL FOR SOME SCATTERED THUNDERSTORM ACTIVITY TO GRAZE THE SOUTHEAST EDGE OF THE FORECAST AREA...BUT THAT POTENTIAL IS LOOKING INCREASINGLY SMALL FOR THE AFTERNOON HOURS AS THE WIND AT SEDALIA REMAINS VEERED AND DEW POINTS ARE BEGINNING TO MIX OUT. CUTTER 300 AM.... STILL SOME QUESTIONS CONCERNING THE EVOLUTION OF THE NEXT CONVECTIVE THREAT FOR THE CWA. CURRENTLY...THE UPPER LEVEL LOW WAS LIFTING NNE ACROSS WRN IA WITH A DRY LINE/WK COLD FRONT MOVING EAST INTO THE XTRM WRN CWA. PROFILERS IN KANSAS AND OKLAHOMA DEPICT STG WESTERLIES AT H8 WITH THE DEEP MOIST AXIS NOW SHIFTING EAST TO AN ERN OKLAHOMA TO CENTRAL MO. MAIN CONCERN IS EXACTLY WHERE THE SURFACE BOUNDARIES AND H8 MOIST AXIS WILL BE LOCATED LATE THIS AFTERNOON AND TONIGHT WITH THE NEXT IN THE SERIES OF SHORTWAVE TROUGHS PIVOTS EAST INTO THE CENTRAL PLAINS TONIGHT. GFS/WRF SIMILAR IN DEVELOPING A WEAK SFC LOW IN WRN OKLAHOMA BY LATE THIS EVENING WITH THE WK BOUNDARY STRETCHING ACROSS CENTRAL AND SOUTHWESTERN MO. THE GFS IS A LITTLE FURTHER SOUTH THAN THE WRF WITH THE BOUNDARY POSITION TNGT AS THE SFC LOW RIDES NORTHEAST. THE GFS SUGGESTS THAT THE BOUNDARY WILL BE JUST SE OF OUR CWA WITH THE WRF ABOUT 50 NM FURTHER NORTH. THE BIGGEST DISCREPANCIES IN THE MODELS IS THE LOCATION OF THE H8 MOIST AXIS. THE GFS HOLDS THE MOIST AXIS ALONG THE I-44 CORRIDOR WITH THE WRF SUGGESTING THE MOIST AXIS WILL SURGE NORTH TO A MCI TO IRK LINE. THE FURTHER NORTH POSITION OF THE WRF DOES NOT APPEAR REASONABLE AT THIS TIME GIVEN SUCH STG DRYING AT H8 OCCURRING IN WRN MO. IN ADDITION...THE STG H3 JET FM THE 4 CORNERS TO IA SHOWS LITTLE LONG STREAM SPEED VARIATION WITH THE BOUNDARY TONIGHT ACTUALLY ON THE ANTICYCLONIC SIDE OF THE JET. THE SHORTWAVE TNGT ALSO BECOMES RATHER CHANNELED AS THE UPPER TROUGH BECOMES POSITIVELY TILTED. THE RIGHT ENTRANCE REGION OF THE JET WILL ALSO NOT COME INTO PLAY TNGT. THE ABOVE REASONING SUGGEST THAT ONLY WEAK PRESSURE FALLS ARE LIKELY NORTH AND WEST OF THE BOUNDARY LATE THIS AFTERNOON WHICH WILL MAKE SIGNIFICANT NWD TRANSPORT OF DEEP MOISTURE TNGT DIFFICULT. PREFER THE SCENARIO DISCUSSED BY SPC WHICH KEEPS THE GREATEST THREAT OF SEVERE FOR AREAS JUST SOUTH AND EAST OF OUR CWA. THIS SCENARIO FITS A COMPROMISE BETWEEN THE GFS AND WRF. THE GFS DOES HAVE SOME SUPPORT FROM THE CANADIAN AND UKMET. ALTHOUGH THE GREATEST THREAT WILL BE TO OUR SOUTH AND EAST TONIGHT. THE PROXIMITY OF THE MOIST AXIS TO OUR EXTREME SERN COUNTIES WARRANTS THE MENTION OF SEVERE GIVEN THE POTENTIAL FOR SFC-1KM HELICITIES OF 100-200M2/S2...SFC BASED CAPES FROM 1000-1500 J/KG AND AND STG SFC-6KM OF 60-70 KNOTS. ISOLATED TORNADOES WILL BE POSSIBLE WITHIN THIS AREA TONIGHT WITH THE THREAT OF MORE ELEVATED CONVECTION...DAMAGING WINDS AND LARGE HAIL...FURTHER NORTH...FROM A BUTLER TO MARSHALL TO MACON LINE. IF THE GFS IS MORE CORRECT...THE AXIS OF SEVERE WEATHER WILL BE LOCATED JUST OUTSIDE OF THE CWA. ON THE FLIP SIDE...IF THE WRF IS MORE CORRECT...MORE WIDESPREAD SEVERE WEATHER WILL BE POSSIBLE FOR THE SERN HALF OF THE CWA. DAY SHIFT WILL NEED TO MONITOR CLOSELY DEVELOPMENTS THROUGHOUT THE DAY. OTHERWISE...THE SHORTWAVE PIVOTING EAST ACROSS MISSOURI TNGT WILL PROVIDE FOR A THREAT OF SHOWERS AND A FEW THUNDERSTORMS ACROSS THE NORTHWESTERN HALF OF THE CWA TONIGHT. THE THUNDERSTORMS ARE EXPECTED TO END DURING THE MORNING ON SATURDAY WITH ONLY A FEW SHOWERS POSSIBLE ALONG THE NRN AND ERN BORDERS DURING THE AFTN. COOLER AND DRIER AIR WILL FILTER INTO THE CWA SATURDAY NIGHT AND SUNDAY. CAA SC TO SURGE SE LATE SATURDAY NIGHT AND EARLY SUNDAY BEFORE ERODING SUNDAY AFTN. DB && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 1222 PM CDT FRI SEP 22 2006 .DISCUSSION... FOCUS IS ON THE POTENTIAL FOR SEVERE WEATHER LATER THIS AFTERNOON. THE UPPER LEVEL LOW IS IN EASTERN SOUTH DAKOTA AT THIS HOUR WITH A SHORTWAVE WAVE DIVING DOWN ITS SOUTHWEST SIDE ACROSS WESTERN COLORADO. CLOSER TO HOME A FRONT EXTENDS FROM NORTHEAST MISSOURI TO JUST NORTH OF JOPLIN...SKATING THE SOUTHEAST EDGE OF THE CWA. SHEAR ACROSS THE FRONT IS QUIT HIGH WITH THE LATEST RUC ANALYSIS SHOWING 0-3KM SHEAR AROUND 45-50 KTS. HOWEVER...SATELLITE IMAGERY AND SURFACE DEW POINTS SHOW THE BETTER SURFACE AND ELEVATED MOISTURE LOCATED SOUTH OF THE FRONT. CLOUDS ACROSS SOUTHERN MISSOURI ON VISIBLE SATELLITE IMAGERY LOOK TO SHOW THE EXPECTED LOCATION OF THIS AFTERNOONS EXPECTED ACTIVITY...BASICALLY ALONG AND SOUTH OF A LINE FROM PITTSBURG KANSAS NORTHEAST THROUGH COLUMBIA MISSOURI. STILL... THERE IS THE POTENTIAL FOR SOME SCATTERED THUNDERSTORM ACTIVITY TO GRAZE THE SOUTHEAST EDGE OF THE FORECAST AREA...BUT THAT POTENTIAL IS LOOKING INCREASINGLY SMALL FOR THE AFTERNOON HOURS AS THE WIND AT SEDALIA REMAINS VEERED AND DEW POINTS ARE BEGINNING TO MIX OUT. CUTTER && .PREVIOUS DISCUSSION... STILL SOME QUESTIONS CONCERNING THE EVOLUTION OF THE NEXT CONVECTIVE THREAT FOR THE CWA. CURRENTLY...THE UPPER LEVEL LOW WAS LIFTING NNE ACROSS WRN IA WITH A DRY LINE/WK COLD FRONT MOVING EAST INTO THE XTRM WRN CWA. PROFILERS IN KANSAS AND OKLAHOMA DEPICT STG WESTERLIES AT H8 WITH THE DEEP MOIST AXIS NOW SHIFTING EAST TO AN ERN OKLAHOMA TO CENTRAL MO. MAIN CONCERN IS EXACTLY WHERE THE SURFACE BOUNDARIES AND H8 MOIST AXIS WILL BE LOCATED LATE THIS AFTERNOON AND TONIGHT WITH THE NEXT IN THE SERIES OF SHORTWAVE TROUGHS PIVOTS EAST INTO THE CENTRAL PLAINS TONIGHT. GFS/WRF SIMILAR IN DEVELOPING A WEAK SFC LOW IN WRN OKLAHOMA BY LATE THIS EVENING WITH THE WK BOUNDARY STRETCHING ACROSS CENTRAL AND SOUTHWESTERN MO. THE GFS IS A LITTLE FURTHER SOUTH THAN THE WRF WITH THE BOUNDARY POSITION TNGT AS THE SFC LOW RIDES NORTHEAST. THE GFS SUGGESTS THAT THE BOUNDARY WILL BE JUST SE OF OUR CWA WITH THE WRF ABOUT 50 NM FURTHER NORTH. THE BIGGEST DISCREPANCIES IN THE MODELS IS THE LOCATION OF THE H8 MOIST AXIS. THE GFS HOLDS THE MOIST AXIS ALONG THE I-44 CORRIDOR WITH THE WRF SUGGESTING THE MOIST AXIS WILL SURGE NORTH TO A MCI TO IRK LINE. THE FURTHER NORTH POSITION OF THE WRF DOES NOT APPEAR REASONABLE AT THIS TIME GIVEN SUCH STG DRYING AT H8 OCCURRING IN WRN MO. IN ADDITION...THE STG H3 JET FM THE 4 CORNERS TO IA SHOWS LITTLE LONG STREAM SPEED VARIATION WITH THE BOUNDARY TONIGHT ACTUALLY ON THE ANTICYCLONIC SIDE OF THE JET. THE SHORTWAVE TNGT ALSO BECOMES RATHER CHANNELED AS THE UPPER TROUGH BECOMES POSITIVELY TILTED. THE RIGHT ENTRANCE REGION OF THE JET WILL ALSO NOT COME INTO PLAY TNGT. THE ABOVE REASONING SUGGEST THAT ONLY WEAK PRESSURE FALLS ARE LIKELY NORTH AND WEST OF THE BOUNDARY LATE THIS AFTERNOON WHICH WILL MAKE SIGNIFICANT NWD TRANSPORT OF DEEP MOISTURE TNGT DIFFICULT. PREFER THE SCENARIO DISCUSSED BY SPC WHICH KEEPS THE GREATEST THREAT OF SEVERE FOR AREAS JUST SOUTH AND EAST OF OUR CWA. THIS SCENARIO FITS A COMPROMISE BETWEEN THE GFS AND WRF. THE GFS DOES HAVE SOME SUPPORT FROM THE CANADIAN AND UKMET. ALTHOUGH THE GREATEST THREAT WILL BE TO OUR SOUTH AND EAST TONIGHT. THE PROXIMITY OF THE MOIST AXIS TO OUR EXTREME SERN COUNTIES WARRANTS THE MENTION OF SEVERE GIVEN THE POTENTIAL FOR SFC-1KM HELICITIES OF 100-200M2/S2...SFC BASED CAPES FROM 1000-1500 J/KG AND AND STG SFC-6KM OF 60-70 KNOTS. ISOLATED TORNADOES WILL BE POSSIBLE WITHIN THIS AREA TONIGHT WITH THE THREAT OF MORE ELEVATED CONVECTION...DAMAGING WINDS AND LARGE HAIL...FURTHER NORTH...FROM A BUTLER TO MARSHALL TO MACON LINE. IF THE GFS IS MORE CORRECT...THE AXIS OF SEVERE WEATHER WILL BE LOCATED JUST OUTSIDE OF THE CWA. ON THE FLIP SIDE...IF THE WRF IS MORE CORRECT...MORE WIDESPREAD SEVERE WEATHER WILL BE POSSIBLE FOR THE SERN HALF OF THE CWA. DAY SHIFT WILL NEED TO MONITOR CLOSELY DEVELOPMENTS THROUGHOUT THE DAY. OTHERWISE...THE SHORTWAVE PIVOTING EAST ACROSS MISSOURI TNGT WILL PROVIDE FOR A THREAT OF SHOWERS AND A FEW THUNDERSTORMS ACROSS THE NORTHWESTERN HALF OF THE CWA TONIGHT. THE THUNDERSTORMS ARE EXPECTED TO END DURING THE MORNING ON SATURDAY WITH ONLY A FEW SHOWERS POSSIBLE ALONG THE NRN AND ERN BORDERS DURING THE AFTN. COOLER AND DRIER AIR WILL FILTER INTO THE CWA SATURDAY NIGHT AND SUNDAY. CAA SC TO SURGE SE LATE SATURDAY NIGHT AND EARLY SUNDAY BEFORE ERODING SUNDAY AFTN. DB && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1010 PM EDT FRI SEP 22 2006 .UPDATE /OVERIGHT/... NO ZONE UPDATE ANTICIPATED. LOWS TONIGHT PRETTY MUCH GOING TO BE DEWPOINTS...WEAK HYDROLAPSE RATES WILL PREVENT CRASHING THROUGH THEM. DO EXPECT POCKETS OF LOW CLOUDS TO DEVELOP AND SKY GRIDS MAY NEED TO BE TRENDED UPWARDS. IF THIS ENDS UP NECESSITATING A ZFP UPDATE TO MOCLDY THEN THAT ADJUSTMENT MAY BE NEEDED LATER ON. ALSO OF INTEREST IS THE POSSIBILITY OF A FEW SPRINKLES ALONG THE COAST ESP FROM CAROLINA BEACH SWWD ACRS ALL OF SC. RUC IS MOST BULLISH ON THIS IDEA BUT IS ALSO OVERDONE FOR THE CURRENT HOUR. FOR NOW FEEL THAT ANY ACTIVITY...IF ANY AT ALL...WILL BE ISOLATED TO THE DEGREE THAT IT WILL ONLY BE NOWCAST-WORTHY AND NOT ZFP-UPDATE-WORTHY. && .AVIATION... TERMINALS CURRENTLY VFR. COASTAL TERMINALS ARE REPORTING VFR...BUT WITH A SCATTERED TO BROKEN CLOUD DECK AT 2000-2500 FEET. SOME ISOLATED SHOWERS OFFSHORE TRYING TO MOVE NORTHWEST BUT CURRENTLY DISSIPATING. LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE ON SOUTHEAST WINDS OVERNIGHT. TEMPO MVFR CEILINGS WILL REMAIN POSSIBLE THROUGHOUT THE NIGHT AT THE COASTAL TERMINALS WITH NO REDUCTIONS IN VISIBILITIES EXPECTED. LOW LEVEL MOISTURE EVENTUALLY ADVECTS TOWARDS FLO/LBT BY 03Z GIVING THOSE TERMINALS A CHANCE OF TEMPO MVFR CEILINGS AFTER 03Z. TEMPO IFR CEILINGS ARE POSSIBLE AT FLO/LBT AFTER 08Z BUT VISIBILITIES SHOULD REMAIN VFR DUE TO CLOUD COVER AND GOOD MIXING. ISOLATED SHOWERS POSSIBLE AT THE COASTAL TERMINALS FROM AFTER 09Z UNTIL 18Z BUT FEEL ACTIVITY IS TOO ISOLATED TO INCLUDE IN TAFS. ALL TERMINALS BECOME VFR BY 13-15Z SATURDAY WITH WORSE CASE MID LEVEL CEILINGS AND SOUTH TO SOUTHWEST WINDS 10-15 KNOTS. && .MARINE... EASTERLY LONG PERIOD SWELL (CURRENTLY 15-16 SECOND PERIOD AS MEASURED BY BUOY 41013) CONTINUES MOVING INTO THE COASTAL WATERS THIS EVENING...AND SHOULD CONTINUE THROUGH THE NEXT COUPLE DAYS. AMPLITUDE IS CURRENTLY 4 FT BUT SHOULD BUILD TOWARD 5 FT OVERNIGHT IN OPEN WATERS PER LATEST WAVEWATCH GUIDANCE. DIRECTLY WEST OF THE SHALLOW WATER ON FRYING PAN SHOALS SEAS ARE SIGNIFICANTLY LESS AS MEASURED AT THE OCEAN CREST PIER WAVE GAUGE...ONLY 2 FT. THIS EFFECT IS DUE TO THE LONG PERIOD SWELLS FEELING BOTTOM AND BREAKING ON THE SHOALS LEAVING LESS WAVE ENERGY TO MOVE ON INTO LONG BAY. IN ADDITION TO THE CHANGES MADE TO SEAS...HAVE ADJUSTED WINDS CLOCKWISE AND INCREASED SPEEDS SLIGHTLY AS SUGGESTED BY LATEST LOCAL WRF MODEL. KLTX VWP SUGGESTS A SE LOW LEVEL JET IS ALREADY ORGANIZING IN GOOD AGREEMENT WITH THE MODEL. THANKS FOR COLLABORATION WFO CHS. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...NONE. && $$ UPDATE...MBB AVIATION...MRR MARINE...TRA nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1107 AM EDT FRI SEP 22 2006 .SHORT TERM /REST OF TODAY THROUGH TONIGHT/... MID-LEVEL DRY PUNCH MOVING INTO WESTERN NORTH CAROLINA ON WATER VAPOR IMAGERY. HOWEVER...AMPLE MOISTURE AS OBSERVED ON THE KFFC AND KOKX 12Z SOUNDINGS BETWEEN 850MB AND 600MB...WITH A MODERATE MID-LEVEL SHORTWAVE AS ANALYZED BY THE RUC AND NAM...ENOUGH TO PROVIDE FOR ISOLATED SHOWERS OR SPRINKLES IN THE WESTERN THIRD OF THE STATE. RUC AND NAM FORECAST GOOD LIFT OVER THE WESTERN PIEDMONT THROUGH 18Z...WITH INCREASING SUBSIDENCE FOR THE AFTERNOON. ALTHOUGH 850MB DIVERGENCE IS STRONG AND THE KGSO SOUNDING WAS DRY AND STABLE...ANTICIPATE ENOUGH MOISTURE AND MID- LEVEL LIFT TO SUPPORT A FEW SPRINKLES IN THE TRIAD AND TOWARD ROXBORO AS WAS FORECAST EARLY THIS MORNING. TREND SHOULD BE FOR GRADUALLY REDUCED COVERAGE IN SPRINKLES/ISOLATED SHOWERS AS 850MB THETA-E VALUES DECREASE THIS AFTERNOON. OVERALL DRIER AIR EAST TOWARD THE TRIANGLE WHICH IS FORECAST TO REMAIN THROUGHOUT THE DAY SHOULD LIMIT POTENTIAL FOR SPRINKLES OR AN ISOLATED SHOWER THAT FAR EAST AND HAVE KEPT THE MENTION OF ANY VERY LIGHT PRECIPITATION MAINLY OVER THE NORTHWEST PIEDMONT INTO THIS EVENING. UPDATED GRIDDED AND WORDED FORECASTS ALREADY ISSUED. IN THE UPDATE LEFT TEMPERATURES ABOUT AS PREVIOUSLY FORECAST. LOCAL THICKNESS SCHEME FOR TEMPERATURE WOULD SUGGEST HIGHS IN THE UPPER 70S UNDER FULL SUN. SOME BREAKS IN THE VISIBLE IMAGES EVEN OVER THE TRIAD AND NUDGED TEMPERATURES UP A DEGREE OR TWO...MOST APPARENT ON THE GRIDDED FORECASTS. && .PREV DISCUSSION... (ISSUED 250 AM EDT FRI SEP 22 2006) SHORT TERM /TODAY THROUGH MONDAY/... TODAY THROUGH TONIGHT: A SOLID DECK OF CONVECTIVE DEBRIS CIRRUS PASSING OVER NC SHOULD CONTINUE MOVING ENE AND EXIT THE REGION... HOWEVER WEAK ISENTROPIC UPGLIDE AT 295-300K OVERNIGHT HAS GENERATED A BROKEN TO OVERCAST STRATOCUMULUS DECK OVER THE NORTHWEST PIEDMONT. DEWPOINTS ACROSS CENTRAL NC ARE RUNNING ROUGHLY 4-8 DEGREES HIGHER THAN 24H AGO. AS THE SURFACE HIGH SHIFTS OFFSHORE TODAY AND THE LIGHT EASTERLY BOUNDARY LAYER FLOW INCREASES FROM THE SOUTHEAST... DEWPOINTS WILL CONTINUE TO CLIMB THROUGH THE 50S AND LOWER 60S. LIGHT PRECIP INDUCED BY ISENTROPIC UPGLIDE IN THE 300-305K LAYER HAS FALLEN TO OUR SOUTHWEST OVER MS/AL... AND THIS FORCING IS MODEL-PROJECTED TO SHIFT OVER NORTHWEST NC WITH 850 MB WINDS PICKING UP FROM THE SOUTHWEST... AND THIS COULD SQUEEZE OUT A SPRINKLE OVER THE WESTERN PIEDMONT. BUT IT SHOULD TAKE SOME TIME TO MOISTEN THE MID LEVELS TODAY... PARTICULARLY OVER THE EASTERN CWA WITH 700 MB WINDS GOING WESTERLY AND WITH DIFFLUENT 850 MB WINDS... AND PRECIP SHOULDN'T BE WIDESPREAD OR MEASURABLE. THE GENERAL BROKEN-OVERCAST CEILING WILL NECESSITATE A LOWERING OF MAX TEMPS TODAY IN THE WESTERN PIEDMONT... AND WILL HAVE 71-80 ACROSS THE CWA. THE 850 MB WARM FRONT CONTINUES TO PUSH TO OUR NORTHEAST TONIGHT WITH A SOUTH-SOUTHEAST SURFACE FLOW AND RISING MID LEVEL HEIGHTS OVER THE SOUTHEAST COAST. WITH THIS PATTERN EXPECT LITTLE IN THE WAY OF MID-HIGH CLOUDS TONIGHT... AND AS SUCH THE OVERALL DRIER NAM-WRF'S MOISTURE PROFILE IS PREFERRED HERE. THIS DOES HOWEVER INCREASE THE CHANCES FOR LOW STRATUS TONIGHT AND SKIES SHOULD BECOME OVERCAST MOST PLACES. PREFER THE NAM-WRF'S LOWS IN THE LOWER-MID 60S. APART FROM WEAK LOW LEVEL ISENTROPIC LIFT SPREADING OVER THE STATE... DON'T SEE ANY MECHANISM TO INDUCE MEASURABLE RAIN AND WILL CUT BACK ON POPS OVERNIGHT... ISOLATED SPRINKLES OR DRIZZLE AT WORST. SATURDAY THROUGH MONDAY: THE STRONG UPPER VORTEX EXPECTED TO PRODUCE PROBLEMS FOR THE MID MISSISSIPPI VALLEY TODAY OPENS UP AS IT TRACKS NORTHEAST THROUGH THE GREAT LAKES REGION OVER THE WEEKEND. THE MID LEVEL ANTICYCLONIC FLOW OVER NC GRADUALLY FLATTENS AS THE SURFACE ANAFRONT SLOWLY APPROACHES FROM THE WEST... HOWEVER WITH LIMITED INSTABILITY AND A LACK OF DEEP MOISTURE... EXPECT ONLY ISOLATED SHOWERS AND A POSSIBLE STORM NEAR THE TIME OF MAX HEATING ON SATURDAY. MUCH BETTER RAIN CHANCES WILL ARRIVE WITH AND JUST BEHIND THE FRONT LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT... THE TIMING OF WHICH ON THE LATEST MODEL RUNS AGREES WELL WITH THE CURRENT FORECAST. WILL RETAIN CHANCE POPS FOR THIS PERIOD. WITH THE MID LEVEL FLOW ROUGHLY PARALLEL TO THE SURFACE FRONT... PREFER THE SLIGHTLY SLOWER NAM-WRF FRONTAL PASSAGE. HIGH TEMPS IN THE MID-UPPER 80S SATURDAY AND SUNDAY SHOULD FALL BACK TO THE LOWER-MID 70S FOR MONDAY AS THE POSITIVELY TILTED TROUGH DROPS INTO THE REGION. -GIH LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... AN ELONGATED SURFACE HIGH WILL STRETCH FROM TX NORTHEASTWARD THROUGH THE MIDATLANTIC REGION MONDAY NIGHT INTO TUESDAY WITH BROAD MID LEVEL TROUGHING OVER EASTERN NORTH AMERICA. BOTH THE ECMWF AND GFS DO INDICATE A PERTURBATION PUSHING THROUGH EASTERN NC... INDUCING SOME DEGREE OF SURFACE CYCLOGENESIS OFF THE NC COAST ALONG THE OLD FRONT IN THE DEPARTING UPPER JET'S ENTRANCE REGION. EVEN IF IT DOES OCCUR THOUGH... IT SHOULD HAVE FEW IMPLICATIONS FOR CENTRAL NC CONSIDERING THE SCANT MOISTURE AVAILABLE. WITH LOW LEVEL THICKNESSES PROJECTED TO BE 20-25M BELOW NORMAL... WILL HAVE HIGHS TUESDAY OF 72-78. LITTLE CHANGE NEEDED TO THE REST OF THE WEEK'S FORECAST AS THE SURFACE HIGH CONTINUES TO BUILD OVERHEAD. LIGHT NORTHERLY 850 MB WINDS BECOME WESTERLY AND DIFFLUENT AHEAD OF THE NEXT VORTICITY MAX THAT DROPS INTO THE GREAT LAKES REGION WEDNESDAY INTO THURSDAY AND ATTEMPTS TO REAMPLIFY THE TROUGH OVER THE NORTHEASTERN STATES. ANY FRONT THAT DROPS TO OUR LATITUDE IN THIS REGIME WOULD HAVE MINIMAL MOISTURE TO WORK WITH AND A CONTINUED DRY FORECAST BUT WITH AN INCREASE IN CLOUDS FOR THURSDAY STILL LOOKS REASONABLE IN LIGHT OF THESE LATEST MODEL TRENDS. STILL EXPECT TEMPERATURES TO BE NEAR TO A COUPLE DEGREES BELOW SEASONAL NORMALS. -GIH AVIATION... HIGH PRESSURE OVER THE AREA WILL MOVE EAST AS A COLD FRONT THROUGH THE CENTRAL U.S. WORKS ITS WAY EAST. SOUTHERLY FLOW AHEAD OF THE FRONT HAS INCREASED MOISTURE OVER THE REGION. THEREFORE WE CAN EXPECT CLOUD BASES 4 TO 5 THOUSAND FEET WITH CIRRUS DECK ABOVE. VISIBILITY UNRESTRICTED EXCEPT IFR IN FOG RWI 09Z-13Z. WIND FROM THE SOUTH AT 5 TO 10 MPH. -RHJ && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJF nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CLEVELAND OHIO 1027 PM EDT FRI SEP 22 2006 .AVIATION(02Z-00Z)... WARM FRONT HEADING NORTH AND WILL MOVE NORTH OF THE FORECAST AREA SATAURDAY MORNING. IN THE MEANTIME MVFR AND LOWER CONDITIONS WILL OCCUR. AIRMASS IS STABLE IN NORTHERN OHIO THUS THUNDERSTORMS SEEM TO BE DECREASING AS THEY MOVE NORTHEAST. HOWEVER...LOW LEVEL JET IS FORECAST TO DEVELOP BY 06Z AND THAT MAY HELP AID THUNDERSTORM DEVELOPMENT. ADDED THUNDER TO MOST TAF SITES FOR THE OVERNIGHT. THE SLUG OF SHOWERS CONTINUES TO SPREAD TO THE NORTHEAST WITH IFR AND LOWER CONDITIIONS. AS THE WARM FRONT MOVES NORTH SATURDAY MORNING CONDITIONS WILL DRY OUT SOME WITH VFR OR HIGH MVFR CONDITIONS UNTIL MORE MOISTURE AND THE COLD FRONT GET CLOSER LATER SATURDAY AFTERNOON. THE THREAT FOR SEVERE THUNDERSTORMS SATURDAY AFTERNOON AND EVENING WILL HAVE TO BE MONITORED. SOUTHWEST WINDS WILL INCREASE SATURDAY AHEAD OF THE APPROACHING COLD FRONT. && .SHORT TERM UPDATE (TONIGHT)... RAIN BEGINNING TO REACH INTO THE WRN COUNTIES THIS EVG AND SHWRS AND TSTMS ARE TO OUR WEST. CONSERNED ABOUT TSTMS INTO THE AREA OVERNIGHT ALTHOUGH SPC FCST TOOLS SUGGEST LIMITED IF ANY CAPE ACRS CWA AT THIS TIME AND WHILE THE NAM12 DOES BRING IN 500 OR SO J/KG OVERNIGHT TO THE WEST THE RUC20 DOES NOT. STILL BLV WE COULD GET A FEW TSTMS INTO THE AREA AND THUS WILL LV THE MENTION OF THUNDER IN THE FCST. OTRW TIMING OF PCPN IN PRVS FCST WAS GOOD BUT GVN THE HOUR WL REMOVE TIMING FROM THE WORDING. ALSO WITH WARM ADVN ACRS THE AREA BLV TEMPS HAVE STEADIED OR BOTTOMED ACRS THE CWA. EARLIER HAVE SEEN A FEW UPPER 50S BUT READINGS NOW ARE ALL IN THE LOW/MID 60S. WL REMOVE LOW TEMP WORDING TO REFLECT STEADY OR RISING TEMPS OVERNIGHT. MADE ON TEMP CHG FOR SAT TO THE CLE GROUP AND RAISED HIGHS TO THE MID 70S FROM LOWER 70S. && .SHORT TERM(TNT-MON)... TEMPERATURES NEVER REALLY GOT AS HIGH AS PREDICTED TODAY. EXPECTING EARLY LOWS TONIGHT AROUND 60...WITH TEMPS RISING A FEW DEGREES TOWARD MORNING WITH THE APPROACH/PASSAGE OF A WARM FRONT. RIGHT NOW WRAPPED UP SYSTEM ACROSS THE CENTRAL PLAINS WITH LOW CENTER ACROSS SOUTHERN MN AND OCCLUDED/COLD FRONT INTO EASTERN IOWA AND MISSOURI. THE WARM FRONT IS LOCATED ACROSS MISSOURI. RAIN WITH A CHC OF TS SHOULD DEVELOP AND EXPAND NORTHWARD AROUND AND AFTER MIDNIGHT. EXPECTING A LULL IN PRECIP FOR THE FIRST HAVE OF SAT UNTIL DYNAMICS KICK IN. AREA IN A SLT RISK OF SEVERE THUNDERSTORMS. AMPLE SHEAR WILL BE PRESENT ALONG WITH MOISTURE...WILL JUST HAVE TO GET ENOUGH INSTABILITY TOGETHER. MAV TEMPS WERE IN THE UPPER 70S...HAVE UNDERCUT AND GONE WITH LOWER/MID 70S SAT IN THE WARM SECTOR. FRONT SAT NIGHT/SUN MORNING. THIS IS WHERE MODELS SPREAD SOME WITH GFS FASTER AND MORE SOUTHERN WITH THE LOW TRACK...AND THE NAM SLOWER AND FURTHER NORTH. SHOWERS ON THE BACKSIDE WITH UPPER TROUGH AXIS STILL TO COME THROUGH. H8 TEMPS GET INTO THE SINGLE DIGITS. SFC TEMPS COOL IN THE 60S. MONDAY SHRA WILL WANE...BUT WILL STILL BE FAIRLY CLOUDY. HIGH PRESSURE WORKS IN TO OUR SOUTH. && .EXTENDED (TUE-FRI)... NORTHWEST FLOW DEVELOPS INTO ANOTHER DEEP EASTERN TROUGH WITH AN ASSOCIATED COLD FRONTAL PASSAGE AROUND WED EVE. WE WILL BE STUCK IN THE UPPER TROUGH THROUGH THE END OF THE FORECAST WITH LARGE WESTERN RIDGE BUILDING INTO CANADA. HAVE PRECIP CHCS IN ASSOCIATION WITH THE FRONT AND THEN IN THE DAYS FOLLOWING WITH THE UPPER TROUGH. SKY COVER AND TEMPS COINCIDE. GFS AND ITS ENSEMBLE MEMBERS RUNNING FAIRLY CONSISTENTLY THROUGH THE EXTD...WHICH IS GOOD NEWS FOR CONFIDENCE LEVELS. && .CLE WATCHES/WARNINGS/ADVISORIES... .OH...NONE. .PA...NONE. && $$ SHORT TERM UPDATE...TK SHORT TERM...OUDEMAN LONG TERM...OUDEMAN AVIATION...KIELTYKA oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OHIO 940 PM EDT FRI SEP 22 2006 .SHORT TERM UPDATE (TONIGHT)... RAIN BEGINNING TO REACH INTO THE WRN COUNTIES THIS EVG AND SHWRS AND TSTMS ARE TO OUR WEST. CONSERNED ABOUT TSTMS INTO THE AREA OVERNIGHT ALTHOUGH SPC FCST TOOLS SUGGEST LIMITED IF ANY CAPE ACRS CWA AT THIS TIME AND WHILE THE NAM12 DOES BRING IN 500 OR SO J/KG OVERNIGHT TO THE WEST THE RUC20 DOES NOT. STILL BLV WE COULD GET A FEW TSTMS INTO THE AREA AND THUS WILL LV THE MENTION OF THUNDER IN THE FCST. OTRW TIMING OF PCPN IN PRVS FCST WAS GOOD BUT GVN THE HOUR WL REMOVE TIMING FROM THE WORDING. ALSO WITH WARM ADVN ACRS THE AREA BLV TEMPS HAVE STEADIED OR BOTTOMED ACRS THE CWA. EARLIER HAVE SEEN A FEW UPPER 50S BUT READINGS NOW ARE ALL IN THE LOW/MID 60S. WL REMOVE LOW TEMP WORDING TO REFLECT STEADY OR RISING TEMPS OVERNIGHT. MADE ON TEMP CHG FOR SAT TO THE CLE GROUP AND RAISED HIGHS TO THE MID 70S FROM LOWER 70S. && .AVIATION(00Z-00Z)... WARM FRONT HEADING NORTH AND WILL MOVE NORTH OF THE FORECAST AREA SATAURDAY MORNING. IN THE MEANTIME MVFR AND LOWER CONDITIONS WILL OCCUR. AIRMASS IS STABLE IN NORTHERN OHIO THUS THUNDERSTORMS SEEM TO BE DECREASING AS THEY MOVE NORTHEAST...NO THUNDER MENTIONED IN THE TAFS FOR THE OVERNIGHT...CANNOT RULE OUT AN ISOLATED THUNDERSTORM...THIS WILL CONTINUED TO BE MONITORED. A SLUG OF SHOWERS WILL BE SPREADING FROM WEST TO EAST STARTING AT 03Z WITH IFR AND LOWER CONDITIIONS. AS THE WARM FRONT MOVES NORTH SATURDAY MORNING CONDITIONS WILL DRY OUT SOME WITH VFR OR HIGH MVFR CONDITIONS UNTIL MORE MOISTURE AND THE COLD FRONT GET CLOSER LATER SATURDAY AFTERNOON. THE THREAT FOR SEVERE THUNDERSTORMS SATURDAY AFTERNOON AND EVENING WILL HAVE TO BE MONITORED. SOUTHWEST WINDS WILL INCREASE SATURDAY AHEAD OF THE APPROACHING COLD FRONT. && .SHORT TERM(TNT-MON)... TEMPERATURES NEVER REALLY GOT AS HIGH AS PREDICTED TODAY. EXPECTING EARLY LOWS TONIGHT AROUND 60...WITH TEMPS RISING A FEW DEGREES TOWARD MORNING WITH THE APPROACH/PASSAGE OF A WARM FRONT. RIGHT NOW WRAPPED UP SYSTEM ACROSS THE CENTRAL PLAINS WITH LOW CENTER ACROSS SOUTHERN MN AND OCCLUDED/COLD FRONT INTO EASTERN IOWA AND MISSOURI. THE WARM FRONT IS LOCATED ACROSS MISSOURI. RAIN WITH A CHC OF TS SHOULD DEVELOP AND EXPAND NORTHWARD AROUND AND AFTER MIDNIGHT. EXPECTING A LULL IN PRECIP FOR THE FIRST HAVE OF SAT UNTIL DYNAMICS KICK IN. AREA IN A SLT RISK OF SEVERE THUNDERSTORMS. AMPLE SHEAR WILL BE PRESENT ALONG WITH MOISTURE...WILL JUST HAVE TO GET ENOUGH INSTABILITY TOGETHER. MAV TEMPS WERE IN THE UPPER 70S...HAVE UNDERCUT AND GONE WITH LOWER/MID 70S SAT IN THE WARM SECTOR. FRONT SAT NIGHT/SUN MORNING. THIS IS WHERE MODELS SPREAD SOME WITH GFS FASTER AND MORE SOUTHERN WITH THE LOW TRACK...AND THE NAM SLOWER AND FURTHER NORTH. SHOWERS ON THE BACKSIDE WITH UPPER TROUGH AXIS STILL TO COME THROUGH. H8 TEMPS GET INTO THE SINGLE DIGITS. SFC TEMPS COOL IN THE 60S. MONDAY SHRA WILL WANE...BUT WILL STILL BE FAIRLY CLOUDY. HIGH PRESSURE WORKS IN TO OUR SOUTH. && .EXTENDED (TUE-FRI)... NORTHWEST FLOW DEVELOPS INTO ANOTHER DEEP EASTERN TROUGH WITH AN ASSOCIATED COLD FRONTAL PASSAGE AROUND WED EVE. WE WILL BE STUCK IN THE UPPER TROUGH THROUGH THE END OF THE FORECAST WITH LARGE WESTERN RIDGE BUILDING INTO CANADA. HAVE PRECIP CHCS IN ASSOCIATION WITH THE FRONT AND THEN IN THE DAYS FOLLOWING WITH THE UPPER TROUGH. SKY COVER AND TEMPS COINCIDE. GFS AND ITS ENSEMBLE MEMBERS RUNNING FAIRLY CONSISTENTLY THROUGH THE EXTD...WHICH IS GOOD NEWS FOR CONFIDENCE LEVELS. && .CLE WATCHES/WARNINGS/ADVISORIES... .OH...NONE. .PA...NONE. && $$ SHORT TERM UPDATE...TK SHORT TERM...OUDEMAN LONG TERM...OUDEMAN AVIATION...KIELTYKA oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 931 PM EDT FRI SEP 22 2006 .SHORT TERM /REST OF TONIGHT/... WIDESPREAD AREA OF -SHRA WITH EMBEDDED TSTMS NOW ACRS WESTERN 1/2 FCST AREA THIS EVNG AS WARM FRONT CONTINUES TO SLOWLY LIFT NORTH ACRS WESTERN/CNTRL KY. RUC INDCG ELEVATED INSTABILITY WILL CONTINUE TO OVERSPREAD FCST AREA THRU OVERNIGHT HOURS ON NOSE OF 40-50KT 850 LLJ. LO LVL CONV AXIS WILL SET UP ACRS SRN 1/2 FCST AREA OVERNIGHT AND THIS SHOULD PROMOTE CONTINUED PCPN THRU THE NIGHT. RADAR AND SAT IMAGES CONFIRM THIS THINKING WITH CLUSTERS OF TSTMS EXTNDG ALL THE WAY BACK INTO SRN MISSOURI. MAY SEE STRONG TSTMS...BUT SEVERE THREAT SHOULD REMAIN SW OF FCST AREA. HAVE INCREASED TO CAT POPS ACRS ALL BUT SE FCST AREA FOR OVERNIGHT AS WARM FRONT LIFTS NORTH INTO REGION. UPDATE OUT...PREV DISCUSSION FOLLOWS. RYAN && .PREV DISCUSSION... /ISSUED 738 PM EDT FRI SEP 22 2006/ AVIATION /00Z-24Z/... COMPLICATED FCST THIS EVNG. DEEP SFC LO ACRS NRN PLAINS WITH AN OCCLUDED FRONT EXTENDING THRU MID MISSISSIPPI VLY BACK SW INTO SRN PLAINS. WARM FRONT EXTNDG SE ACRS WESTERN AND SOUTHERN ILLINOIS INTO WESTERN KY. MARGINAL LLWS ALONG WARM FRONT LATE TONIGHT...AND HAVE LEFT OUT OF TAFS ATTM. LARGE CLUSTER OF TSRA HAS DVLPD OVER LAST SVRL HOURS IN ALONG WARM FRNTL BNDRY AND IS MOVING NORTHEAST TOWARDS FCST AREA THIS EVNG. SHOULD SEE THIS MCS MOVE INTO REGION THIS EVNG AS WARM FRONT CONTINUES TO PROGRESS NORTHEAST. BROAD LO LVL WAA PATTERN AND A STRENGTHENING 40-50 KT 850 LLJ TONIGHT WILL ALSO CONTRIBUTE TO NMRS -SHRA AFFECTING ALL TAF SITES OVERNIGHT. HAVE INDICATED PREVAILING -SHRA AT ALL TAF SITES BTWN 03-06Z WITH A CB MENTION FOR THUNDER. RUC INDCG SOME WEAK ELEVATED INSTABILITY OVERNIGHT ACRS WESTERN FCST AREA WHICH SHOULD SUPPORT A FEW -TSRA. EXPECTING A BREAK IN TERMS OF PCPN COVERAGE AS WARM FRONT LIFTS THRU REGION AFTER DAYBREAK SAT MRNG BEFORE INCREASE IN CONVECTION FOR AFTN HOURS. 12Z GFS INDCG DVLPG AND DEEPENING SFC LO ALONG FRNTL BNDRY MOVING FROM THE MID MISSISSIPPI VLY ON SAT MRNG INTO NRN INDIANA BY 00Z SUN. IN WARM SECTOR SAT AFTN...MODERATE INSTABILITY COMBINED WITH HIGH AMOUNTS OF BL SHEAR SHOULD SUPPORT SCT SVR -TSRA AFT 18Z. HAVE BROUGHT VCTS INTO ALL TAF SITES FOR AFTN HOURS WITH FOUR HOUR TEMPO GROUPS AFT 18Z. ADDL TSRA ARE LIKELY IN FORM OF A SQUALL LINE AFT 00Z SUN AHEAD OF COLD FRONT. THIS WILL BE ADDRESSED IN 06Z TAF FCST. SE WINDS TONIGHT WILL VEER TO SSW ON SAT IN WARM SECTOR AND BECOME GUSTY DURING AFTN HOURS. RYAN PREV DISCUSSION... /ISSUED 348 PM EDT FRI SEP 22 2006/ SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... BIG DIFFERENCES BETWEEN NAM AND GFS...BUT IN COMPARING WITH ECMWF AND UKMET...GFS SEEMS TO BE MORE REASONABLE DESPITE STILL HAVING SOME CONVECTIVE FEEDBACK. GFS PRETTY PROGRESSIVE WITH CLOSED LOW JUST TO NORTH OF FA THROUGH EARLY SUNDAY MORNING. MOST PROMISING DYNAMICS AND PLENTY OF LOW LEVEL SHEAR AND INSTABILITY AHEAD OF MAIN SQALL LINE TO PRODUCE POTENTIAL SUPERCELL ACTIVITY LATE AFTERNOON SAT...WITH MORE OF A POSSIBLE SQUALL LINE EVENT IN THE MID AND LATE EVENING. HAVE GONE CATEGORICAL CHANCES FOR SATURDAY...WITH MORNING THUNDERSTORMS NOT AS LIKELY SEVERE...BUT SOME THREAT OF ISOLATED HEAVY RAIN IN THE SOUTHWEST. SFC WARM FNT APPROACHING FROM CENTRAL PLAINS BRINGING GOOD SHOT OF 70 TO LOW 70 DEWPOINTS ESPECIALLY IN THE WEST FOR SATURDAY. HAVE MENTION OF SEVERE IN GRIDS WITH DAMAGING WINDS GREATEST THREAT FROM ESPECIALLY 18-02Z. LINGERING CHANCE OF SHOWERS WITH A MENTION OF EARLY MORNING THUNDERSTORMS IN THE FAR EAST FOR SUNDAY...THEN CHANCE FOR SHRA IN THE NORTH IN WRAP AROUND THROUGH EARLY SUNDAY AFTERNOON. LONG TERM /MONDAY THROUGH FRIDAY/... EXTENDED FCST STARTING MON HAS HIGH PRESSURE BUILDING OVER OHVLY FROM THE MIDWEST AS LOW PRESSURE RETREATS FROM GTLKS REGION. EXPECT A GRADUAL WARMING OF THE AIRMASS THROUGH MIDWEEK AS A SFC LOW TRACKS INTO THE GTLKS WED. THIS WILL SEE A TRAILING COLD FRONT MOVE THROUGH OHVLY ON WED NITE AND THURS IN RESPONSE TO A STRONG AND PERSISTENTLY DEEPENING H5 TROF OVER THE ERN 1/2 OF CONUS. MILD AIR WILL SURGE AHEAD OF THE CDFNT...AND THE STRENGTHENING H5 L/W TROF WILL ALLOW FOR A STRONG PUSH OF COOL CONTINENTAL AIR INTO THE OHVLY ON NRLY FLOW AS STRONG SFC HIGH IN THE MIDWEST SETS UP. STRENGTH OF SYSTEM WED NITE AND THURS HAS ME INCREASE POPS AS THE FLOW AHEAD OF IT AND SIGNIFICANT HEIGHT FALLS BEHIND IT WOULD LIKELY SEE A LINE OF CONVECTION MOVE THROUGH THE REGION. COLD POOL SHOWERS POSSIBLE FOR REMAINDER OF THURS AND INTO FRI...BUT ONLY HAVE 20% POSSIBILITY HERE BEING THE LAST DAY OF FCST. TEMPS WERE GENERALLY BUMPED UP AHEAD OF WED NITE FRONT AND DROPPED BEHIND IT...NOT TOO FAR FROM MEX GUID. FRANKS && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 738 PM EDT FRI SEP 22 2006 .AVIATION /00Z-24Z/... COMPLICATED FCST THIS EVNG. DEEP SFC LO ACRS NRN PLAINS WITH AN OCCLUDED FRONT EXTENDING THRU MID MISSISSIPPI VLY BACK SW INTO SRN PLAINS. WARM FRONT EXTNDG SE ACRS WESTERN AND SOUTHERN ILLINOIS INTO WESTERN KY. MARGINAL LLWS ALONG WARM FRONT LATE TONIGHT...AND HAVE LEFT OUT OF TAFS ATTM. LARGE CLUSTER OF TSRA HAS DVLPD OVER LAST SVRL HOURS IN ALONG WARM FRNTL BNDRY AND IS MOVING NORTHEAST TOWARDS FCST AREA THIS EVNG. SHOULD SEE THIS MCS MOVE INTO REGION THIS EVNG AS WARM FRONT CONTINUES TO PROGRESS NORTHEAST. BROAD LO LVL WAA PATTERN AND A STRENGTHENING 40-50 KT 850 LLJ TONIGHT WILL ALSO CONTRIBUTE TO NMRS -SHRA AFFECTING ALL TAF SITES OVERNIGHT. HAVE INDICATED PREVAILING -SHRA AT ALL TAF SITES BTWN 03-06Z WITH A CB MENTION FOR THUNDER. RUC INDCG SOME WEAK ELEVATED INSTABILITY OVERNIGHT ACRS WESTERN FCST AREA WHICH SHOULD SUPPORT A FEW -TSRA. EXPECTING A BREAK IN TERMS OF PCPN COVERAGE AS WARM FRONT LIFTS THRU REGION AFTER DAYBREAK SAT MRNG BEFORE INCREASE IN CONVECTION FOR AFTN HOURS. 12Z GFS INDCG DVLPG AND DEEPENING SFC LO ALONG FRNTL BNDRY MOVING FROM THE MID MISSISSIPPI VLY ON SAT MRNG INTO NRN INDIANA BY 00Z SUN. IN WARM SECTOR SAT AFTN...MODERATE INSTABILITY COMBINED WITH HIGH AMOUNTS OF BL SHEAR SHOULD SUPPORT SCT SVR -TSRA AFT 18Z. HAVE BROUGHT VCTS INTO ALL TAF SITES FOR AFTN HOURS WITH FOUR HOUR TEMPO GROUPS AFT 18Z. ADDL TSRA ARE LIKELY IN FORM OF A SQUALL LINE AFT 00Z SUN AHEAD OF COLD FRONT. THIS WILL BE ADDRESSED IN 06Z TAF FCST. SE WINDS TONIGHT WILL VEER TO SSW ON SAT IN WARM SECTOR AND BECOME GUSTY DURING AFTN HOURS. RYAN && .PREV DISCUSSION... /ISSUED 348 PM EDT FRI SEP 22 2006/ SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... BIG DIFFERENCES BETWEEN NAM AND GFS...BUT IN COMPARING WITH ECMWF AND UKMET...GFS SEEMS TO BE MORE REASONABLE DESPITE STILL HAVING SOME CONVECTIVE FEEDBACK. GFS PRETTY PROGRESSIVE WITH CLOSED LOW JUST TO NORTH OF FA THROUGH EARLY SUNDAY MORNING. MOST PROMISING DYNAMICS AND PLENTY OF LOW LEVEL SHEAR AND INSTABILITY AHEAD OF MAIN SQALL LINE TO PRODUCE POTENTIAL SUPERCELL ACTIVITY LATE AFTERNOON SAT...WITH MORE OF A POSSIBLE SQUALL LINE EVENT IN THE MID AND LATE EVENING. HAVE GONE CATEGORICAL CHANCES FOR SATURDAY...WITH MORNING THUNDERSTORMS NOT AS LIKELY SEVERE...BUT SOME THREAT OF ISOLATED HEAVY RAIN IN THE SOUTHWEST. SFC WARM FNT APPROACHING FROM CENTRAL PLAINS BRINGING GOOD SHOT OF 70 TO LOW 70 DEWPOINTS ESPECIALLY IN THE WEST FOR SATURDAY. HAVE MENTION OF SEVERE IN GRIDS WITH DAMAGING WINDS GREATEST THREAT FROM ESPECIALLY 18-02Z. LINGERING CHANCE OF SHOWERS WITH A MENTION OF EARLY MORNING THUNDERSTORMS IN THE FAR EAST FOR SUNDAY...THEN CHANCE FOR SHRA IN THE NORTH IN WRAP AROUND THROUGH EARLY SUNDAY AFTERNOON. LONG TERM /MONDAY THROUGH FRIDAY/... EXTENDED FCST STARTING MON HAS HIGH PRESSURE BUILDING OVER OHVLY FROM THE MIDWEST AS LOW PRESSURE RETREATS FROM GTLKS REGION. EXPECT A GRADUAL WARMING OF THE AIRMASS THROUGH MIDWEEK AS A SFC LOW TRACKS INTO THE GTLKS WED. THIS WILL SEE A TRAILING COLD FRONT MOVE THROUGH OHVLY ON WED NITE AND THURS IN RESPONSE TO A STRONG AND PERSISTENTLY DEEPENING H5 TROF OVER THE ERN 1/2 OF CONUS. MILD AIR WILL SURGE AHEAD OF THE CDFNT...AND THE STRENGTHENING H5 L/W TROF WILL ALLOW FOR A STRONG PUSH OF COOL CONTINENTAL AIR INTO THE OHVLY ON NRLY FLOW AS STRONG SFC HIGH IN THE MIDWEST SETS UP. STRENGTH OF SYSTEM WED NITE AND THURS HAS ME INCREASE POPS AS THE FLOW AHEAD OF IT AND SIGNIFICANT HEIGHT FALLS BEHIND IT WOULD LIKELY SEE A LINE OF CONVECTION MOVE THROUGH THE REGION. COLD POOL SHOWERS POSSIBLE FOR REMAINDER OF THURS AND INTO FRI...BUT ONLY HAVE 20% POSSIBILITY HERE BEING THE LAST DAY OF FCST. TEMPS WERE GENERALLY BUMPED UP AHEAD OF WED NITE FRONT AND DROPPED BEHIND IT...NOT TOO FAR FROM MEX GUID. FRANKS && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 133 PM CDT FRI SEP 22 2006 .MESOSCALE UPDATE... AT 1 PM...DRYLINE HAD PUSHED TO NEAR A NOWATA...TO EUFAULA...TO MCALESTER LINE WITH THE AXIS OF DEEPER MOISTURE FURTHER EASTWARD MARKED BY EXTENSIVE CUMULUS FIELD. PROFILER DATA AND RUC ANALYSIS SHOW WIND FIELDS OVER THE AREA REMAINED VEERED WITH LITTLE DIRECTIONAL SHEAR NOTED. SPEEDS REMAIN STRONG ENOUGH TO PRODUCE AMPLE DEEP LAYER SHEAR...AND AS SUCH...STORMS WHICH INITIATED OVER NORTHWEST ARKANSAS QUICKLY DEVELOPED ROTATION. THE LACK OF DIRECTION SHEAR HOWEVER HAS RESULTED IN NEAR STRAIGHT LIGHT HODOGRAPHS...MAKING DEVIANT STORM MOTIONS NECESSARY TO REALIZE SIGNIFICANTLY HIGHER HELICITIES. INSTABILITY AXIS REMAINS IN PLACE OVER EASTERN OKLAHOMA AND NORTHWEST ARKANSAS...WITH CAP STRENGTH CONTINUING TO WEAKEN EAST OF THE DRYLINE. ADDITIONAL STORM ARE LIKELY TO DEVELOP BY BY 4 PM...AND ONCE UPDRAFTS BECOME ESTABLISHED AND ANY EASTWARD MOTION CAN BE REALIZED...THE RISK OF SIGNIFICANT SEVERE WEATHER WILL INCREASE. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 948 PM EDT FRI SEP 22 2006 ...HIGH RISK FOR RIP CURRENTS SATURDAY... .SHORT TERM /TONIGHT/...A FULL ONSHORE FLOW HAS FINALLY BEEN ESTABLISHED ACROSS THE RGN AS HIGH PRES CNTRD OFF THE MID ATLC COAST CONTINUES TO PROPAGATE E AND A STRONG VERTICALLY STACKED MID- LATITUDE CYCLONE CHURNS ACROSS THE CNTRL/NRN PLAINS. KCLX VWP IS ALREADY SHOWING A RATHER POTENT NOCTURNAL JET SETTING UP WITH 1000 FT AS HIGH AS 25 KT. UNLIKE THE PAST FEW NGTS...THE 23/00Z OBSERVED CHS RAOB AND RUC FCST SOUNDINGS SUGGEST THE BNDRY LYR WL REMAIN FAIRLY WELL MIXED THROUGH THE NGT WHICH RESULT IN A SLGTLY WARMER TEMPS COMPARED TO THIS MRNG ESP AT THE COAST. XPCT LOWS TO RANGE FROM THE UPR 60S INLAND TO THE MID 70S ALONG THE IMMEDIATE COAST. COULD SEE AN ISOLD SHOWER OR TWO MOVE TOWARD THE CHARLESTON COUNTY COAST LATE TNGT AS THE SLY FLOW INCRS BUT WE BELIEVE THE CHANCES FOR MEASURABLE PCPN ARE LIKELY TOO LOW TO INCLUDE A MENTION ATTM. WL MAKE A FEW TWEAKS TO THE GRIDDED FCSTS MAINLY TO ACCOUNT FOR NEAR TERM TRENDS BUT THE FCST PKG AS A WHOLE IS IN EXCELLENT SHAPE. AN UPDATE TO THE ZONE FCSTS WL THEREFORE NOT BE ISSUED. && .MARINE...SEAS CONTINUE TO BE DOMINATED BY ELY SWELLS OF 14-15 SECONDS WITH OCNL SWELL SETS OF 16-17 SECONDS. BUOY...PILOT BOAT AND TOWER OBSERVATIONS SUGGEST SEAS ARE GENERALLY 3-5 FT WITHIN 20 NM AND 4-6 FT PSBLY AS HIGH AS 7 FT ACROSS THE GA OFFSHORE WTRS. THE SCA FOR HAZARDOUS SEAS WL OBVIOUSLY CONTINUE FOR THE GA OFFSHORE WTRS. BUOY 41004 IS CURRENTLY REPORTING COMBINED SEAS OF 6 FT AND THE 18Z HURCN WW3 GUIDANCE SUGGESTS 6 FT SEAS COULD GET INTO THE WTRS N OF EDISTO BEACH AFT MIDNGT. THE OVERALL CONFIDENCE OF THIS OCCURRING REMAINS QUIET LOW SO AFT COORD WITH THE GREAT FOLKS UP AT WFO ILM... WE WL KEEP CONDITIONS JUST BELOW SCA CRITERIA AND CARRY A HEADLINE THAT SMALL CRAFT SHOULD EXERCISE CAUTION. THE MAIN HAZARD HERE WL BE FOR DANGEROUS WAVE ACTION NEAR THE CHARLESTON HARBOR ENTRANCE AS WELL AS OTHER INLET/BAY/SOUND AND RIVER ENTRANCES. THE CHARLESTON HARBOR PILOT BOAT REPORTED RATHER HAZARDOUS WAVE ACTION IN THE HARBOR ENTRANCE EARLIER THIS EVNG. && .AVIATION...XPCT VFR CONDITIONS TO PREVAIL FOR THE NXT 24 HRS. PATCHES OF STRATOCU WL CROSS THE TERMINALS FOR MUCH OF THE NGT. A BRIEF PERIOD OF MVFR CIGS COULD OCCUR AFT MIDNGT AS LARGER OR THICKER PATCHES MOVE INLAND FROM THE ATLC BUT THE XPCTD TIME DURATION WL LIKELY REMAIN LESS THAN 15-30 MIN AT ANY ONE TIME. THUS A TEMPO GROUP WAS NOT ADDED TO EITHER TAF /KCHS OR KSAV/. THIS WL NEED TO BE REEVALUATED FOR THE 06Z TAF CYCLE ONCE THE 00Z MODEL GUIDANCE IS RCVD. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS AMZ374. && $$ ST sc AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 830 PM MDT FRI SEP 22 2006 .DISCUSSION...AS CONFIRMED BY THE 00Z KUNR SOUNDING...WINDS OFF THE SFC HAVE VEERED TO THE NORTH WHICH HAS ALLOWED THE DOWNSLOPE AREA AROUND THE BLKHLS TO SHIFT A BIT TO THE S/W. THIS HAS ALLOWED THE PCPN TO MOVE BACK INTO THE RAPID CITY TO HERMOSA AREA. FCST SOUNDINGS SHOW WINDS OFF THE SFC FROM A N TO NNE DIRECTION INTO SAT MRNG WHICH SHOULD KEEP THE PCPN IN THE RAPID CITY TO HERMOSA. FREEZING LEVELS HAVE CHANGED VERY LITTLE FROM THE 12Z TO 00Z SOUNDING (7300-7500 FT). HOWEVER...TEMPS ABOVE 700MB HAVE COOLED A COUPLE DEGREES CENTIGRADE...AND BOTH THE NAM/RUC AT 00Z SUGGEST THIS COOLING WILL DESCEND WITH FREEZING LEVELS DROPPING TO ABOUT 6000 FT OVERNIGHT. HEAVIER PCPN IN THE NRN BLKHLS WILL LIKELY DROP THIS LVL EVEN FURTHER. THEREFORE...EVEN THOUGH RECENT CALLS TO SPOTTERS IN THE 6000 TO 6500 RANGE REVEAL MOSTLY RAIN...THIS WILL CHANGE OVERNIGHT. SNOW LEVELS WILL DROP TO AROUND 5500 FT...AND POSSIBLY AS LOW AS 5000 FT. THIS WOULD LIKELY KEEP DEADWOOD ALL RAIN WITH A CHANGEOVER TO SNOW NEAR LEAD. WITH BOTH NAM/RUC PAINTING A QPF BULLSEYE OF ANOTHER 1.75 INCHES OVERNIGHT OVR THE NRN BLKHLS...SIGNIFICANT ACCUMULATIONS ARE LIKELY ABOVE 5500 FT AS INDICATED IN CURRENT FCST SO WILL NOT BE CHANGING MUCH IN THE WINTER WEATHER HIGHLIGHTS. MOISTURE WRAPPING AROUND THE UPR LOW OVR ERN SD WILL CONTINUE TO BRING WDSPRD RAIN TO THE REST OF THE AREA THRU SAT MRNG...WITH A GRADUAL END FROM NORTH TO SOUTH DURING THE AFTN...WITH THE VAST MAJORITY OF PCPN OVER BY SAT EVE. WILL UP POPS ACCORDINGLY THRU SAT MRNG. WINDS SHOULD REMAIN JUST BELOW ADVISORY CRITERIA OVERNIGHT...BUT LIKELY PICK BACK UP ON SAT. THUS...WILL KEEP WIND ADVISORY GOING. && .AVIATION...WDSPRD MVFR/IFR CONDS ACRS ALL RTES THROUGH SAT MRNG WITH RAIN AND HIGHER ELEVATION SNOWS CONTINUING. PCPN WILL GRADUALLY END FROM NORTH TO SOUTH BY SAT AFTN ACRS THE RTES. NW WIND GUSTS OF 35 TO 40KTS REMAIN POSSIBLE THRU SAT. && UNR...WATCHES/WARNINGS/ADVISORIES... SD...HEAVY SNOW WARNING NORTHERN BLACK HILLS THROUGH SATURDAY MORNING. ...WIND ADVISORY THROUGH SATURDAY FOR NORTHWESTERN SD. WY...NONE. && $$ JOHNSON sd AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 220 PM MDT FRI SEP 22 2006 .DISCUSSION...CURRENT SURFACE MAP SHOW DEEP LOW PRESSURE ALONG THE SOUTH DAKOTA/MINNESOTA BORDER WITH INVERTED TROF EXTENDING INTO NORTHWEST SOUTH DAKOTA. WIDESPREAD RAIN FALLING ACROSS THE NORTHERN PLAINS. SNOW LEVEL IN THE NORTHERN BLACK HILLS IS 5800-6000 FEET. SNOW ACCUMULATIONS OF 3-4 INCHES SO FAR ABOVE 6000 FEET...POSSIBLY MORE ON SOME OF THE HIGHER PEAKS. PORTION OF CENTRAL/SOUTHERN BLACK HILLS HAVE HAD VERY LITTLE PRECIPITATION DUE TO DOWNSLOPE FLOW. WIDESPREAD PRECIPITATION WILL CONTINUE THROUGH THE NIGHT...WITH HEAVIEST AMOUNTS ACROSS THE PLAINS OF NORTHWEST SOUTH DAKOTA AND NORTHERN BLACK HILLS. HEAVY SNOW WILL CONTINUE ACROSS THE NORTHERN BLACK HILLS...AND SHOULD START TO ACCUMULATE AT A FASTER RATE ONCE THE SUN SETS. NAM/RUC INDICATE ANOTHER 1-2 INCHES OF LIQUID FOR THE NORTHERN BLACK HILLS ON TOP OF WHAT HAS ALREADY FALLEN. SNOW LEVELS WILL DROP OVER NIGHT...DOWN TO AROUND 5000 FEET. THE HEAVIEST ACCUMULATIONS WILL BE ABOVE 5500 FEET...WHERE ANOTHER 4 TO 6 INCHES IS LIKELY. AGAIN...IF TEMPERATURES COOL JUST A FEW DEGREES MORE OVERNIGHT...LEAD/DEADWOOD WOULD HAVE A BETTER CHANCE OF HEAVY SNOW. WILL KEEP HEAVY SNOW WARNING IN PLACE FOR THE NORTHERN BLACK HILLS. FOR THE CENTRAL BLACK HILLS...LITTLE IF ANY SNOW HAS ACCUMULATED SO FAR. THE THREAT OF HEAVY SNOW IS IN THE MORE REMOTE AREAS OF NORTHWEST PENNINGTON COUNTY ZONE...NORTHWEST OF DEERFIELD AND ROCHFORD. ONLY MINOR SNOW ACCUMULATIONS EXPECTED FURTHER SOUTH AROUND HILL CITY/MT. RUSHMORE. WILL DROP THE WINTER STORM WATCH FOR THE CENTRAL BLACK HILLS...AND MENTION LOCALLY HIGHER AMOUNTS IN THE HIGHER ELEVATIONS OF FAR WESTERN PART OF THE CENTRAL BLACK HILLS. FORECAST SOUNDING SUPPORT A MIX OR RAIN/SNOW ACROSS PORTIONS OF NORTHEAST WYOMING TONIGHT...WITH LITTLE IN THE WAY OF ACCUMULATIONS. GUSTY WINDS WILL CONTINUE ON THE PLAINS OF NORTHWESTERN SOUTH DAKOTA...WILL LEAVE WIND ADVISORY IN PLACE THROUGH SATURDAY AFTERNOON. UPPER LEVEL LOW BEGINS TO PULL OUT OF EASTERN SOUTH DAKOTA SATURDAY...WITH DRIER AIR WORKING IN FROM THE NORTH. SHOULD BE WIDESPREAD PRECIPITATION ACROSS THE AREA IN THE MORNING...WITH BEST FOCUS SHIFTING INTO SOUTH CENTRAL SOUTH DAKOTA DURING THE DAY. PRECIPITATION WILL QUICKLY END ACROSS THE FORECAST AREA LATE SATURDAY. DRY WEATHER EXPECTED SUNDAY/MONDAY...WITH TEMPERATURES WARMING BACK INTO THE 70S BY MONDAY. EXTENDED...WEAK HIGH PRESSURE WILL BRING DRY AND WARM CONDITIONS TO THE AREA FOR THE BEGINNING OF THE WORK WEEK. THE GFS CONTINUES TO SHOW A MID WEEK SYSTEM AND AFFILIATED COLD FRONT MOVING THROUGH THE NORTHERN PLAINS...SO HAVE CONTINUED TO GO WITH A SLIGHT CHANCE OF RAIN SHOWERS TUES NIGHT INTO WEDNESDAY...ALONG WITH COOLING HIGH TEMPS DOWN ON WEDNESDAY. DRY WEATHER IS EXPECTED FOR THE REMAINDER OF THE WEEK. && .AVIATION...RAIN WILL CONTINUE ACROSS THE AREA TODAY...WITH SOME SNOW OVER THE BLACK HILLS INTO PARTS OF NORTHEAST WYOMING...BRINGING MVFR AND IFR CEILINGS AND VISIBILITIES WHICH WILL LAST THROUGH SATURDAY MORNING BEFORE SLOWLY IMPROVING. NORTHWEST WINDS OF 25 TO 35KTS WITH SOME GUSTS UP TO 40 KTS WILL ALSO LAST THROUGH THIS EVENING. && UNR...WATCHES/WARNINGS/ADVISORIES... SD...HEAVY SNOW WARNING NORTHERN BLACK HILLS THROUGH SATURDAY MORNING. ...WIND ADVISORY TODAY THROUGH SATURDAY FOR NORTHWESTERN SD. WY...NONE. && $$ sd AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 940 AM MDT FRI SEP 22 2006 .DISCUSSION...CURRENT SURFACE MAP SHOW DEEP LOW PRESSURE NEAR SIOUX FALLS...WITH INVERTED TROF EXTENDING INTO NORTHWEST SOUTH DAKOTA. LARGE AREA OF RAIN FALLING ACROSS THE NORTHERN PLAINS. NUMEROUS REPORTS OF RAINFALL OVER AN INCH ACROSS THE SOUTH DAKOTA PLAINS OVERNIGHT...WITH MORE TO FALL TODAY/TONIGHT. SOME SNOWFALL ABOVE 6000 FEET THIS MORNING. SNOTEL SITES IN NORTHERN BLACK HILLS ABOVE 6100 FEET INDICATE THAT AN INCH OR TWO OF SNOW MAY HAVE ACCUMULATED. ALSO HAVE A REPORT OF 4 INCHES NEAR O'NEIL PASS. 12Z KUNR SOUNDING SHOWS WINDS FROM 330-360 DEGREES BELOW 600MB. DOWNSLOPE PRECIPITATION VOID IS ACROSS SOUTHERN BLACK HILLS TO JUST SOUTH OF RAPID CITY. 12Z NAM/RUC SIMILAR THROUGH TODAY...WITH WIDESPREAD PRECIPITATION FALLING ACROSS THE CWA. QPF AMOUNTS TODAY/TONIGHT RANGE FROM 1.00-1.50 INCHES ON THE PLAINS...TO 2.00+ INCHES IN THE NORTHERN BLACK HILLS. EXCEPTION WILL BE SOUTHERN BLACK HILLS WHICH WILL REMAIN IN THE DOWNSLOPE HOLE THROUGH TONIGHT. NAM/RUC HAVE WINDS FROM 850-600MB VEERING TO THE NORTHEAST THIS AFTERNOON...WITH UPSLOPE ENHANCEMENT ACROSS NORTHERN BLACK HILLS TO RAPID CITY. TEMPERATURES REMAIN COLD ENOUGH FOR SNOW ABOVE 6000 FEET TODAY...WITH NAM/RUC SHOWING 700MB TEMPERATURES COOLING ANOTHER DEGREE OR TWO DURING THE DAY. THIS WOULD ALLOW SNOW LEVELS WILL DROP A LITTLE DURING THE DAY. WITH CURRENT REPORTS AND EXPECTED SNOWFALL...WILL UPGRAGE NORTHERN BLACK HILLS TO HEAVY SNOW WARNING WITH UPDATE. WILL LEAVE CENTRAL HILLS IN A WATCH...AS ONLY A SMALL PART OF THAT ZONE IS GETTING HEAVY PRECIPITATION. SNOW ACCUMULATIONS TODAY WILL BE CONFINED TO 6000 FEET AND ABOVE...WITH SNOW LEVELS DROPPING TO AROUND 5300-5500 FEET TONIGHT. IF TEMPERATURES WERE TO DROP JUST A FEW DEGREES MORE...HEAVY SNOW COULD FALL IN THE LEAD/DEADWOOD AREA TONIGHT. && UNR...WATCHES/WARNINGS/ADVISORIES... SD...HEAVY SNOW WARNING NORTHERN BLACK HILLS THROUGH SATURDAY MORNING. WINTER STORM WATCH TONIGHT THROUGH SATURDAY MORNING FOR THE CENTRAL BLACK HILLS. ...WIND ADVISORY TODAY THROUGH SATURDAY FOR NORTHWESTERN SD. WY...NONE. && $$ sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 1232 PM CDT FRI SEP 22 2006 .DISCUSSION... THE MID STATE IS NEARLY CLEAR OF PRECIPITATION AT THIS TIME. ONLY A FEW LIGHT SHOWERS ARE OCCURRING ACROSS FAR NORTHWESTERN COUNTIES. A WARM FRONT WILL CONTINUE TO MOVE SLOWLY NORTHWARD THROUGH THE MID STATE TODAY. HOWEVER...LITTLE IN THE WAY OF CONVERGENCE IS INDICATED ALONG THE BOUNDARY. LATEST RUC MODEL SHOWING LITTLE IN THE WAY OF DYNAMICS WORKING UNTIL LATE THIS AFTERNOON WHEN SOME PVA MOVES INTO WESTERN TN. A FEW BREAKS IN THE CLOUD COVER MAY OCCUR...PARTICULARLY ACROSS SOUTHERN ZONES. ANY ADDITIONAL HEATING WILL ACT TO FURTHER DESTABILIZE THE ATMOSPHERE AND THUS...SCATTERED CONVECTION WILL BE POSSIBLE. FOR THE FCST...WILL UPDATE AND LOWER POPS DOWN TO AROUND 50% FOR MOST AREAS. && .OHX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 21 tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1123 PM CDT FRI SEP 22 2006 .UPDATE...RUC IS ANALYZING A WEAK S/WV ACROSS THE TEXAS COAST W/ THE COASTAL BEND ON BACKSIDE OF THE FEATURE. THINK THIS FEATURE MAY HAVE CAUSED SLT BUCKLING IN THE PGRAD AND CONTRIBUTED TO UNEXPECTED DROP OFF IN WINDS ACROSS THE NEARSHORE WATERS THIS EVENING. AS THE S/WV MOVES FURTHER AWAY FROM THE REGION ITS INFLUENCE ON THE PGRAD WILL DECREASE AND THE WINDS SHOULD INCREASE ONCE AGAIN OVERNIGHT (IN FACT PTAT2 ALREADY SHOWING SIGNS OF INCREASING AGAIN MOST RECENT OB). THEREFORE...KEPT THE SCA GOING ALL MARINE ZONES INCLUDING THE BAYS DESPITE SOME OF THE RECENT LOWER WIND SPEEDS IN A FEW OF THE TCOON AND NDBC SITES. ALSO UPDATED ZONES TO SHOW MORE CLOUD COVER AS WE ARE SEEING MUCH MORE STRATUS FORMING TONIGHT AS COMPARED TO LAST NIGHT AND CLEANED UP SOME WIND WORDING THERE AS WELL. && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 7 PM SATURDAY FOR THE FOLLOWING ZONES: COASTAL WATERS BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS BAFFIN BAY TO PORT ARANSAS 20 TO 60 NM... AND WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 7 AM SATURDAY FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS... AND BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O'CONNOR. && $$ MJG tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 906 PM CDT FRI SEP 22 2006 .UPDATE... SEVERE CONVECTION CONTINUES TO DEVELOP IN MOIST/UNSTABLE AND STRONGLY SHEARED AIRMASS NORTH OF THE RED RIVER THIS EVENING... LIKELY IN RESPONSE TO INTENSIFYING LOW-LEVEL JET INCREASING MASS CONVERGENCE ALONG RETREATING DRYLINE. MODELS HAVE BEEN CONSISTENT ON BACKBUILDING THE AXIS OF SCATTERED THUNDERSTORMS ACROSS THE NORTH CENTRAL AND NORTHWEST PORTIONS OF THE FORECAST AREA THROUGH THE NIGHT...BUT VERY LITTLE CONVECTION HAS DEVELOPED THUS FAR SOUTH OF THE RED RIVER. WILL MAINTAIN STATUS QUO WITH THE CURRENT FIRST PERIOD POPS...AS DRYLINE AND ZONE OF STRONGEST CONVERGENCE WILL CONTINUE TO RETREAT NORTHWESTWARD IN RESPONSE TO MID-LEVEL SHORTWAVE TROUGH CURRENTLY APPROACHING SOUTHEAST COLORADO. OTHER ELEMENTS OF THE FORECAST APPEAR TO BE ON TRACK AS WELL THIS EVENING...AND ONLY MINOR ADJUSTMENTS WILL BE MADE TO DEWPOINT... WIND...AND CLOUD COVER GRIDS TO ACCOUNT FOR CURRENT TRENDS. UPDATED PRODUCTS WILL BE ISSUED SHORTLY. 65/DD && .AVIATION... AGREE WITH CWSU THAT CONVERGENCE HAS BEEN MINIMIZED ALONG DRYLINE THIS AFTN...BUT SHOULD INCREASE AS LOW LVL FLOW BECOMES MORE SSE/SELY THROUGH 04-05Z. HOWEVER...ELEVATED MIXED LAYER (CAP) SEEMS MORE STOUT S OF 580DM LINE WHICH PER RUC...XTNDS FROM KGYI...TO KDTO/KLUD...TO NEAR KRPH. THUS ONLY ISOLD SHRA/TSRA MNLY NW-NE OF D/FW TAF SITES THROUGH 08-10Z...WHEN COLD FRONT SHOULD START TO OVERTAKE DRYLINE TO THE NW AND INITIATE ELEVATED STORMS AS S/W OVER TX/OK PANHANDLES APPROACHES AND HEIGHTS FALL. WILL KEEP TIMING OF MVFR CIGS ARND SAME TIMES 06-07Z AT KACT...TO 09-10Z AT D/FW SITES...WITH VFR CONDS TIL THEN. LOOK FOR BEST PROBS TO OCCUR D/FW AREA 10Z-17Z TIME FRAME AS CD FNT APPROACHES AND FORCING GETS BETTER WITH LINEAR...ELEVATED ACTIVITY EARLY...BECMG MORE SFC-BASED BY 18Z/AFTR NEAR D/FW...THEN ARRIVING INTO KACT VCNTY BY 21Z/AFTR. CD FRONT ARRIVES ACRS D/FW FROM 19-21Z WITH WND SHIFT TO WNW/NW...THEN INTO KACT LIKELY AFTR 00Z SUN. && .PREV DISCUSSION... /ISSUED 305 PM CDT FRI SEP 22 2006/ DISCUSSION... NEXT LOBE OF ENERGY SWINGING AROUND UPPER LOW IN THE CENTRAL PLAINS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO NORTHERN PORTIONS OF THE CWA TONIGHT...AND SPREAD SOUTHEAST ACROSS THE REGION EARLY SATURDAY. MODELS HAVE BEEN CONSISTENT AND IN GENERAL AGREEMENT IN DEVELOPING PRECIP OVER NORTHERN PORTIONS TONIGHT...WITH A COLD FRONT MOVING THROUGH THE AREA LATE SATURDAY. RAINS WILL END IN SOUTHERN PORTIONS BY EARLY SUNDAY WITH TEMPERATURES BECOMING MORE MODERATE AS WE HEAD INTO THE FIRST FULL WEEK OF FALL. WEAK RIDGING TO BEGIN SUNDAY BUT THE PERSISTENT BROAD TROUGH OVER THE EASTERN HALF OF THE U.S. WILL SEND ANOTHER SHOT OF COLD AIR AND ENERGY SOUTHWARD MIDWEEK...WITH A FRONT AND RAIN MOVING THROUGH LATE WEDNESDAY AND THURSDAY. DESPITE THESE RAIN CHANCES...IT SHOULD BE A PLEASANT WEEK AS TEMPERATURES REMAIN MILD...QUITE A CHANGE FROM RECENT WEEKS. && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /42/05 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 644 PM CDT FRI SEP 22 2006 .AVIATION... AGREE WITH CWSU THAT CONVERGENCE HAS BEEN MINIMIZED ALONG DRYLINE THIS AFTN...BUT SHOULD INCREASE AS LOW LVL FLOW BECOMES MORE SSE/SELY THROUGH 04-05Z. HOWEVER...ELEVATED MIXED LAYER (CAP) SEEMS MORE STOUT S OF 580DM LINE WHICH PER RUC...XTNDS FROM KGYI...TO KDTO/KLUD...TO NEAR KRPH. THUS ONLY ISOLD SHRA/TSRA MNLY NW-NE OF D/FW TAF SITES THROUGH 08-10Z...WHEN COLD FRONT SHOULD START TO OVERTAKE DRYLINE TO THE NW AND INITIATE ELEVATED STORMS AS S/W OVER TX/OK PANHANDLES APPROACHES AND HEIGHTS FALL. WILL KEEP TIMING OF MVFR CIGS ARND SAME TIMES 06-07Z AT KACT...TO 09-10Z AT D/FW SITES...WITH VFR CONDS TIL THEN. LOOK FOR BEST PROBS TO OCCUR D/FW AREA 10Z-17Z TIME FRAME AS CD FNT APPROACHES AND FORCING GETS BETTER WITH LINEAR...ELEVATED ACTIVITY EARLY...BECMG MORE SFC-BASED BY 18Z/AFTR NEAR D/FW...THEN ARRIVING INTO KACT VCNTY BY 21Z/AFTR. CD FRONT ARRIVES ACRS D/FW FROM 19-21Z WITH WND SHIFT TO WNW/NW...THEN INTO KACT LIKELY AFTR 00Z SUN. && .PREV DISCUSSION... /ISSUED 305 PM CDT FRI SEP 22 2006/ DISCUSSION... NEXT LOBE OF ENERGY SWINGING AROUND UPPER LOW IN THE CENTRAL PLAINS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO NORTHERN PORTIONS OF THE CWA TONIGHT...AND SPREAD SOUTHEAST ACROSS THE REGION EARLY SATURDAY. MODELS HAVE BEEN CONSISTENT AND IN GENERAL AGREEMENT IN DEVELOPING PRECIP OVER NORTHERN PORTIONS TONIGHT...WITH A COLD FRONT MOVING THROUGH THE AREA LATE SATURDAY. RAINS WILL END IN SOUTHERN PORTIONS BY EARLY SUNDAY WITH TEMPERATURES BECOMING MORE MODERATE AS WE HEAD INTO THE FIRST FULL WEEK OF FALL. WEAK RIDGING TO BEGIN SUNDAY BUT THE PERSISTENT BROAD TROUGH OVER THE EASTERN HALF OF THE U.S. WILL SEND ANOTHER SHOT OF COLD AIR AND ENERGY SOUTHWARD MIDWEEK...WITH A FRONT AND RAIN MOVING THROUGH LATE WEDNESDAY AND THURSDAY. DESPITE THESE RAIN CHANCES...IT SHOULD BE A PLEASANT WEEK AS TEMPERATURES REMAIN MILD...QUITE A CHANGE FROM RECENT WEEKS. && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /42/05 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 907 AM CDT FRI SEP 22 2006 .UPDATE... THE PROBLEM OF THE DAY WILL BE WINDS ACROSS SE TX. THE WIND SPEEDS WERE ALREADY IN THE 15 TO 20 MPH RANGE AT 14Z OVER THE INLAND AREAS AND 20 TO 25 MPH RANGE AT THE COAST. THE VAD WIND PROFILE COUPLED WITH THE ADJACENT PROFILERS AND THE NAM AND RUC ALL INDICATE 35 TO 40 KNOT WINDS AT EITHER 2000 FEET OR THE 925 MB SURFACE. FIGURED THAT WITH HEATING THE WINDS WILL PICK UP OVER WIND ADVISORY CRITERIA OVER ALL OF SE TX...AND ISSUED THE ADVISORY THROUGH 6 PM. THE OTHER ISSUE FOR THE DAY WILL BE RAIN CHANCES. THE MSAS DATA SHOWED THE SURFACE THETA-E RIDGE JUST OFF THE COAST AND OVER THE BPT AREA. WILL KEEP THE 20 PERCENT CHANCE IN FOR TODAY. 40 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...SMALL CRAFT ADVISORY UNTIL 7 PM FRIDAY FOR THE FOLLOWING ZONES: AND GALVESTON. WIND ADVISORY UNTIL 6 PM FRIDAY FOR THE FOLLOWING ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS... COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS... HOUSTON...JACKSON...LIBERTY...MADISON...MATAGORDA... MONTGOMERY...POLK...SAN JACINTO...TRINITY...WALKER... WALLER...WASHINGTON...AND WHARTON. GM...SMALL CRAFT ADVISORY UNTIL 7 PM FRIDAY FOR THE FOLLOWING ZONES: GALVESTON BAY...AND MATAGORDA BAY. SMALL CRAFT ADVISORY UNTIL 7 AM SATURDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...AND WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1005 AM CDT FRI SEP 22 2006 .UPDATE...DATA ANALYSIS CONTINUES TO SHOW NEARLY VERTICALLY STACKED LOW PRESSURE NEAR THE KFSD AREA. DRY SLOT EVIDENT ON VISIBLE SATELLITE AND WATER VAPOR IMAGERY WORKING AROUND SOUTH SIDE OF THE SYSTEM. IN ADDITION...MAIN BAND OF RAIN HAD LIFTED INTO NORTH CENTRAL WI...AS Q-G CONVERGENCE LIFTING NORTHWARD TOWARD LAKE SUPERIOR. LATEST RUC SUPPORTS DRY SLOT TO CONTINUE PUSHING INTO PORTIONS OF THE FORECAST AREA...ESPECIALLY NORTHEAST IOWA AND SOUTHWEST WI. RUC ALSO INDICATED MAIN FORCING MANIFESTED BY UPPER LEVEL DIVERGENCE AND DEEP Q-G CONVERGENCE SHOULD CONTINUE LIFTING NORTHWARD THIS AFTERNOON. AS MIDNIGHT SHIFT ARX FORECASTER NOTED...BEST INSTABILITY APPEARS TO RESIDE SOUTH OF OUR FORECAST AREA. MUCAPE VALUES BUILD TO NEAR 1000J/KG IN FAR SOUTHWEST CORNER OF WI...GENERALLY ALONG AND EAST OF LINE FROM KDLL TO KDBQ BETWEEN 20Z-02Z. THUS...SEVERE WEATHER THREAT STILL LOOKS TO RESIDE SOUTH OF THE FORECAST AREA THIS AFTERNOON AND EVENING. CURRENT DATA BASE APPEARS ON TRACK...TAKING INTO ACCOUNT EFFECTS OF DRY SLOT. THEREFORE...BEST RAIN PROBABILITIES WILL BE ACROSS EAST AND NORTH SECTIONS OF THE FORECAST AREA THIS AFTERNOON. UPDATED ZONES SHOULD BE ISSUED BY ABOUT 1530Z THIS MORNING...WITH ONLY MINOR TWEAKS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ THOMPSON wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 446 AM CDT SAT SEP 23 2006 .DISCUSSION... MAIN DILEMMA FOR TDAS FCST IS TRYING TO FIGURE OUT WHAT THE WALL OF WATER FROM NE OK TO W KY IS GOING TO DO TO THE PCPN CHCS AND SVR WX THRT OVR THE SE HLF OF FA. WV ALG CDFNT NOW MOVING INTO NE OK HAS BGN TO GENERATE THE NXT ROUND OF CNVTN...AND XTRAP OF N EDGE OF THIS PCPN TAKES IT TO NR A KVIH...KSPI LN DURG THE MRNG. WITH OUTFLO BNDRY RMNG SO ACTIVE OVR N AR AM SMWHAT SKEPTICAL THAT HVY RAIN WL GET THAT FAR N...BUT SINCE MDLS HV PEGGED THIS REDVLPMT HV MENTIONED HVY RAINS ALG AND S OF ABV MENTIONED LINE FOR THIS MRNG. SM AREAS OF E OZARKS CULD GET OVR AN INCH OF RAIN THIS MRNG...BUT SINCE YSTDAS HVY RAIN IN OUR FA WAS VRY SPOTTY THINK THAT MOST AREAS SHUD BE ABLE TO HOLD THIS RAINFALL. AS FAR AS SVR WX THRT WITH THIS FIRST ROUND OF CNVTN...BLV THAT IT WL PRIMARILY STAY S OF OUR AREA...IN VCNTY OF OUTFLO BNDRY NR AR/MO BDR. AFT THIS MRNGS FIRST WV OF CNVTN PASSES THRU THE SE HLF OF FA...QUESTION BCMS HOW MUCH AND HOW INTS REDVLPMT WL OCR AHD OF CDFNT DURG THE AFTN. BLV THAT MRNG CNVTN/RAIN COOLED AMS/CLD CVR IS REALLY GOING TO INHIBIT DESTABLIZATION DURG THE ERY AND MID AFTN HRS...SO WHILE CAN'T TOTALLY RULE OUT REDVLPMNT BGNG TO THINK THAT INTENSITY MAY BE LIMITED. NAM FCSTS MLCAPES TO REBOUND TO ARND 400 J/KG BY LT AFTN...WHILE BOTH THE GFS AND LATEST RUC INCR CAPES INTO THE 1500-2000 J/KG RANGE. OTHER QUESTION IS WHERE THE CDFNT WL BE DURG AFTN. IF GFS IS CORRECT FNT WL BE EXITING OUR FA IN THE 18- 20Z TIME FRAME...PLACING MAIN THRT OF AFTN DVLPMT E OF OUR AREA. FOR THE TIME BEING HV GONE WITH A BLEND OF THE GFS/NAM FOR THIS AFTN PARAMETERS...AND KEPT POPS HI. MEANWHILE...SHWRS ASSOC WITH MAIN TROF IN COOLER AIR OVR E KS/NW MO SHUD MV ACR NW SECTIONS OF THE FA DURG THE MRNG. KEPT A LO POP GOING IN THESE AREAS DURG AFTN...BUT EVEN THESE LO POPS MAY BE A BIT TOO HI IF MID LVL DRY SLOT EVOLVES AS DEPICTED BY GFS AND NAM. WITH THE UPR LO AND TROF FINALLY BGNG TO MOVE COOLER AND MORE STBL AMS SHUD BE ADV INTO THE MID MSVLY THIS AFTN AND TNGT. THIS MEANS THAT ANY CNVTN THAT DOES REFORM OVR SE MO/S IL THIS AFTN SHUD BE EXITING OUR FA BY ERY THIS EVE...AND ANY LINGERING SHWRS IN THE COOLER AIR SHUD DSPT AS WELL. CERTAINLY...COOLER AND MORE TRANQUIL CONDITIONS ARE IN THE OFFING FOR MOST OF TNGT AND SUN...ALTHO MDL RH PROGS SUGGEST A GD DEAL OF LO LVL CLDNS SPREADING ACR AREA LT TNGT AND SUN...AND CULD SEE A FEW SPRINKLES AS WELL. TRUETT && .AVIATION... FOR THE 06Z TAFS...MOST OF THE SHRA AND TSRA SHOULD REMAIN S OF THE TAF SITES DURING THE LT NGT HRS. TSRA WILL LIKELY RETURN TO COU AND STL AREA SAT MRNG AS THE FNT LFTS SLIGHTLY NWD WITH APPROACH OF SFC WV MOVG NEWD THRU ERN OK AND INTO SWRN MO. SHRA/TSRA WILL LIKELY ALSO OCCUR FURTHER N IN UIN AS THE MID- UPR LVL TROF APPROACHES FM THE WEST. MOST OF THE SHRA AND TSRA ACTIVITY SHOULD EVENTUALLY PUSH S AND E OF THE TAF SITES BY SAT EVNG WITH THE PASSAGE OF THE CDFNT. VFR CEILINGS AND VSBYS SHOULD CONT THRU AT LEAST 12Z SAT TIL THE SHRA/TSRA PUSH BACK INTO THE CWA. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 339 AM EDT SAT SEP 23 2006 .SHORT TERM /TODAY THROUGH MONDAY NIGHT/... SFC HIGH PRESSURE OVER NORTHEAST/MIDATL STATES WILL SINK SSE TODAY. REMAINDER OF THE BL WILL FOLLOW SUIT LEADING TO A DEEP LAYER OF WARM AND MOIST S TO SWRLY FLOW. AS SUCH A WARM AND MUGGY AFTERNOON IS EXPECTED THIS FIRST DAY OF FALL AND CU DEVEL SHOULD BE FARILY ROBUST. WEAK SHOWER ACTIVITY JUST OFFSHORE FROM WRN BRUNSWICK AND OFF OF SC....A COMBO OF WEAK LLJ AND CONV AXIS...WILL PROBABLY DIMINISH WITHIN A FEW HRS OF SUNRISE. THIS IDEA IS SUPPORTED BY THE RUC, WHICH HAS RECENTLY INITIALIZED WITH THE ACTIVITY PRETTY WELL. AND ALTHOUGH A LAST MINUTE DECISION TO INCLUDE THEM MAY BE MADE FOR NOW THEY WILL LIKELY ONLY MERIT A NOWCAST OR TWO...IF EVER MAKING IT ONSHORE THAT IS. WITH CONTINUED WARM AND MOIST ADVECTION OVERNIGHT EXPECT GRADUAL INC IN MIDLVL CLOUDS AND A MUGGY NIGHT. FLOW SHOULD BE PARELLEL ENOUGH TO THE COAST THAT IF OFFSHORE SHOWERS REDEVEL THEY SHOULD REMAIN OVER WATER. BL APPEARS TO STAY MIXED ENOUGH TO PRECLUDE MUCH FOG DEVEL EVEN IF THE MID CLOUDS STAY JUST TO OUR NW, WHICH IS A POSSIBILITY SINCE THE OVERALL EVOLUTION OF THE SUNDAY/MONDAY PATTERN APPEARS SLOWER THAN PREV THOUGHT. ACCORDINGLY...POPS HAVE BEEN TRIMMED SUNDAY TO SHOW SLOWER TIMING. MOST OF THE DAY SHOULD BE MUGGY WITH MORE ROBUSTLY INCREASING MID LVL CLOUDS. LATER IN THE AFTERNOON POPS WILL STILL BE RISING AS THE COLD FRONT NEARS...AND THE SEA BREEZE MAY EVEN MAKE A CONTRIBUTION ALTHOUGH THE SYNOPTIC FLOW WILL KEEP IT FROM MOVING INLAND VERY FAR OR VERY QUICKLY. IF THE GFS TIMING IS CORRECT THEN POPS SHOULD START RAMPING UP QUICKLY AOA 03Z MONDAY (MAYBE A BIT SOONER W) AS DEEP ASCENT OVERSPREADS THE AREA. THE ASCENT IS DEEP BUT NOT TERRIBLY STRONG SO MODERATE RAIN WILL BE POSSIBLE DUE TO A DEEP NEARLY SATURATED LAYER BUT ANY HEAVY RAIN SHOULD BE CONFINED TO LOCALIZED POCKETS OF CONVECTION. THE FRONT WILL PROGRESSING ACRS THE AREA AT THIS TIME AND SHOULD ROUGHLY PARELLEL THE COAST AND BE JUST OFFSHORE AOA 12Z MON. THE EASTERMOST COUNTIES WILL HAVE A TOUGH TIME SHAKING RAIN CHANCES THROUGH MOST OF MONDAY. AS THE TROUGH THAT DROVE THE FRONT INTO THE AREA ALREADY BEGINS LIFTING OUT A POTENT SHORTWAVE LAGGING BEHIND WILL BEING TO MOVE IN FROM THE WEST. ACCORDING TO THE GFS THE TROP WILL BE FOLDING DOWN TO ABOUT 500MB OVER ATL BY MONDAY AFTERNOON WITH THIS FEATURE. THIS WILL RESULT IN FAIRLY STRONG VERTICAL MOTION OVER THE ERN CAROLINAS. MOST OF THIS STRONG ASCENT WILL BE OCCURRING OVER THE DEEP STABLE BL OVER WRN ZONES BUT COASTAL COUNTIES MAY STILL HAVE A SHALLOW ENOUGH STABLE LAYER FOR SOME ELEVATED MOISTURE AND INSTABILITY AND COULD SEE ANOTHER ROUND OF APPREACIABLE RAINFALL. SHOULD THE BOUNDARY BE JUST A BIT FARTHER TO THE EAST MOST OF THE RAIN WILL REMAIN OFFSHORE. TOO EARLY TO IRON OUT THE DETAILS. && .AVIATION... PROBLEMATICAL FORECAST THIS MORNING...ESPECIALLY AT FLO WHICH IS NOW EXPERIENCING VLIFR CONDITIONS FOR VSBY AND CIG. HAVE NO GOOD EXPLANATION WHY IT HAS GONE SO LOW HERE...NEITHER GUIDANCE NOR CLIMO NOR THE SYNOPTIC SITUATION WOULD SUGGEST THIS SCENARIO. REST OF THE TAFS ARE BEHAVING. RADAR HAS PATCHES OF LIGHT SHOWER ACTIVITY MOVING ASHORE BEFORE DISSIPATING SOUTH OF CAPE FEAR WHICH IS LEADING TO TEMPO MVFR FOR CIGS AT CRE AND MYR. PATCHY MVFR FOG ELSEWHERE THIS MORNING EXCEPT FOR ILM WHICH SEEMS TO LIE JUST OUTSIDE OF THE BEST MOISTURE TAP. && .MARINE... LONG PERIOD SWELL FROM DISTANT TROPICAL CYCLONE HELENE CONTINUES TO IMPACT THE COASTAL WATERS. SWELLS ABOUT 4 FT WITH A PERIOD OF 15 SECONDS OUT AT 41013 ACCORDING TO SPECTRAL PLOTS. WITH TIGHTENING SOUTHERLY GRADIENT OVER THE COASTAL WATERS WIND DRIVEN WAVES HAVE ALSO INCREASED...LEADING TO COMBINED SEAS OF 5 FT AT 41013 AND AROUND 4 FT CLOSER TO SHORE. BASED ON LATEST FROM TPC ON HELENE...EXPECT SIGNIFICANT CONTRIBUTION TO COMBINED SEAS FROM THE SWELL COMPONENT TO CONTINUE INTO THE WEEKEND...ALTHOUGH IT LOOKS LIKE WE HAVE ALREADY SEEN ITS PEAK. PRESENT SHADOWING EFFECT OF SWELL ENERGY FOR WATERS WEST OF CAPE FEAR DUE TO FRYING PAN SHOALS WILL BECOME LESS OF A FACTOR DURING THE DAY TODAY AS SWELL ENERGY DECREASES. WINDS AND SEAS WILL PICK UP AGAIN SUNDAY IN ADVANCE OF COLD FROPA SET FOR EARLY MONDAY. MAY SEE SCA CRITERIA MET FOR SEAS SUNDAY NIGHT IN THE OUTER REACHES OF OUR NC WATERS. STUCK WITH THE GFS FOR MOST OF THE FORECAST EXCEPT FOR THE FIRST COUPLE OF PERIOD. AS NOTED BY OPC...THE GFS IS SUPPORTED BY THE ECMWF AND BY THE LATEST HPC MEDIUM RANGE FORECASTER GUIDANCE. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...NONE. && $$ SHORT TERM...MBB AVIATION...REK MARINE...REK nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OHIO 145 AM EDT SAT SEP 23 2006 .AVIATION(06Z-06Z)... WARM FRONT ACROSS SE LOWER MI THRU NE OH WILL LIFT NORTH FORECAST AREA EARLY THIS MORNING. ONE LARGE AREA OF SHOWERS ACRSS SE OH AND KY SHOULD SLIDE OFF TO THE EAST. COUPLE OTHER AREA SHOWERS AND TSTMS NW OH AND EXTRM NERN PTN FORECAST AREA. SHOULD SEE SHOWERS EXPAND FOR AWHILE EARLY THIS MORNING WITH WARM FRONT VCNTY AND 8H JET NOSING INTO AREA BUT THEN SHOULD SEE SHOWERS DCRS IN COVERAGE LATER THIS MORNING AND PERHAPS INTO EARLY AFTERNOON...BEFORE BECOMING MORE WIDESPREAD LATE THIS AFTERNOON AND EARLY TONIGHT WITH APPROACH OF FRONT. MIXSED CIGS AND VSBYS ACROSS THE AREA ATTM MOST MVFR. EXPECT THIS HOLD THIS MORNING THOUGH MFD THRU YNG EXPECTING IFR CIGS. CIGS AND VSBY SHOULD LIFT TO VFR LATE MORNING EARLY AFTERNOON BEFORE LOWERING AGAIN TO WIDESPREAD MVFR CIGS AND VSBYS AS SHOWERS EXPAND LATE AFTERNOON AND TONIGHT. THE THREAT FOR SEVERE THUNDERSTORMS SATURDAY AFTERNOON AND EVENING WILL HAVE TO BE MONITORED. HIGH SHEAR FOR THREAT OF SEVERE WEATHER BUT STABILITY MAY BE LIMITED BECAUSE OF CLOUDS THOUGH SHEAR WOULD MAINTAIN ANY STRONG STORMS THAT INITIATE. && .SHORT TERM UPDATE (TONIGHT)... RAIN BEGINNING TO REACH INTO THE WRN COUNTIES THIS EVG AND SHWRS AND TSTMS ARE TO OUR WEST. CONSERNED ABOUT TSTMS INTO THE AREA OVERNIGHT ALTHOUGH SPC FCST TOOLS SUGGEST LIMITED IF ANY CAPE ACRS CWA AT THIS TIME AND WHILE THE NAM12 DOES BRING IN 500 OR SO J/KG OVERNIGHT TO THE WEST THE RUC20 DOES NOT. STILL BLV WE COULD GET A FEW TSTMS INTO THE AREA AND THUS WILL LV THE MENTION OF THUNDER IN THE FCST. OTRW TIMING OF PCPN IN PRVS FCST WAS GOOD BUT GVN THE HOUR WL REMOVE TIMING FROM THE WORDING. ALSO WITH WARM ADVN ACRS THE AREA BLV TEMPS HAVE STEADIED OR BOTTOMED ACRS THE CWA. EARLIER HAVE SEEN A FEW UPPER 50S BUT READINGS NOW ARE ALL IN THE LOW/MID 60S. WL REMOVE LOW TEMP WORDING TO REFLECT STEADY OR RISING TEMPS OVERNIGHT. MADE ON TEMP CHG FOR SAT TO THE CLE GROUP AND RAISED HIGHS TO THE MID 70S FROM LOWER 70S. && .SHORT TERM(TNT-MON)... TEMPERATURES NEVER REALLY GOT AS HIGH AS PREDICTED TODAY. EXPECTING EARLY LOWS TONIGHT AROUND 60...WITH TEMPS RISING A FEW DEGREES TOWARD MORNING WITH THE APPROACH/PASSAGE OF A WARM FRONT. RIGHT NOW WRAPPED UP SYSTEM ACROSS THE CENTRAL PLAINS WITH LOW CENTER ACROSS SOUTHERN MN AND OCCLUDED/COLD FRONT INTO EASTERN IOWA AND MISSOURI. THE WARM FRONT IS LOCATED ACROSS MISSOURI. RAIN WITH A CHC OF TS SHOULD DEVELOP AND EXPAND NORTHWARD AROUND AND AFTER MIDNIGHT. EXPECTING A LULL IN PRECIP FOR THE FIRST HAVE OF SAT UNTIL DYNAMICS KICK IN. AREA IN A SLT RISK OF SEVERE THUNDERSTORMS. AMPLE SHEAR WILL BE PRESENT ALONG WITH MOISTURE...WILL JUST HAVE TO GET ENOUGH INSTABILITY TOGETHER. MAV TEMPS WERE IN THE UPPER 70S...HAVE UNDERCUT AND GONE WITH LOWER/MID 70S SAT IN THE WARM SECTOR. FRONT SAT NIGHT/SUN MORNING. THIS IS WHERE MODELS SPREAD SOME WITH GFS FASTER AND MORE SOUTHERN WITH THE LOW TRACK...AND THE NAM SLOWER AND FURTHER NORTH. SHOWERS ON THE BACKSIDE WITH UPPER TROUGH AXIS STILL TO COME THROUGH. H8 TEMPS GET INTO THE SINGLE DIGITS. SFC TEMPS COOL IN THE 60S. MONDAY SHRA WILL WANE...BUT WILL STILL BE FAIRLY CLOUDY. HIGH PRESSURE WORKS IN TO OUR SOUTH. && .EXTENDED (TUE-FRI)... NORTHWEST FLOW DEVELOPS INTO ANOTHER DEEP EASTERN TROUGH WITH AN ASSOCIATED COLD FRONTAL PASSAGE AROUND WED EVE. WE WILL BE STUCK IN THE UPPER TROUGH THROUGH THE END OF THE FORECAST WITH LARGE WESTERN RIDGE BUILDING INTO CANADA. HAVE PRECIP CHCS IN ASSOCIATION WITH THE FRONT AND THEN IN THE DAYS FOLLOWING WITH THE UPPER TROUGH. SKY COVER AND TEMPS COINCIDE. GFS AND ITS ENSEMBLE MEMBERS RUNNING FAIRLY CONSISTENTLY THROUGH THE EXTD...WHICH IS GOOD NEWS FOR CONFIDENCE LEVELS. && .CLE WATCHES/WARNINGS/ADVISORIES... .OH...NONE. .PA...NONE. && $$ SHORT TERM UPDATE...TK SHORT TERM...OUDEMAN LONG TERM...OUDEMAN AVIATION...WCR oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 137 AM EDT SAT SEP 23 2006 .AVIATION /06Z-06Z/... THE MORE CONTIGUOUS THUNDERSTORM ACTIVITY WILL CONTINUE TO MOVE SOUTH AND EAST OF THE TERMINALS THIS EVENING. SOME ISOLATED STORMS WILL AFFECT KCVG AND KLUK OVER THE NEXT FEW HOURS...AND PERHAPS DAYTON. CIGS WILL BE MVFR AT TIMES THROUGH 12Z WITH SW WINDS AROUND 12 KTS AND GUSTS NEAR 20 KTS. THERE WILL BE LESS COVERAGE THROUGH 16Z-18Z BEFORE INSTABILITY BUILDS IN ADVANCE OF AN APPROACHING COLD FRONT. SW WINDS WILL GUST OVER 20 KTS AT TIMES WITH MVFR CIGS AND VISIBILITIES LIKELY AGAIN AFTER 23Z AS THE FRONT BEGINS TO PASS ACROSS THE AREA. && .PREV DISCUSSION... /ISSUED 931 PM EDT FRI SEP 22 2006/ SHORT TERM /REST OF TONIGHT/... WIDESPREAD AREA OF -SHRA WITH EMBEDDED TSTMS NOW ACRS WESTERN 1/2 FCST AREA THIS EVNG AS WARM FRONT CONTINUES TO SLOWLY LIFT NORTH ACRS WESTERN/CNTRL KY. RUC INDCG ELEVATED INSTABILITY WILL CONTINUE TO OVERSPREAD FCST AREA THRU OVERNIGHT HOURS ON NOSE OF 40-50KT 850 LLJ. LO LVL CONV AXIS WILL SET UP ACRS SRN 1/2 FCST AREA OVERNIGHT AND THIS SHOULD PROMOTE CONTINUED PCPN THRU THE NIGHT. RADAR AND SAT IMAGES CONFIRM THIS THINKING WITH CLUSTERS OF TSTMS EXTNDG ALL THE WAY BACK INTO SRN MISSOURI. MAY SEE STRONG TSTMS...BUT SEVERE THREAT SHOULD REMAIN SW OF FCST AREA. HAVE INCREASED TO CAT POPS ACRS ALL BUT SE FCST AREA FOR OVERNIGHT AS WARM FRONT LIFTS NORTH INTO REGION. UPDATE OUT...PREV DISCUSSION FOLLOWS. RYAN PREV DISCUSSION... /ISSUED 348 PM EDT FRI SEP 22 2006/ SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... BIG DIFFERENCES BETWEEN NAM AND GFS...BUT IN COMPARING WITH ECMWF AND UKMET...GFS SEEMS TO BE MORE REASONABLE DESPITE STILL HAVING SOME CONVECTIVE FEEDBACK. GFS PRETTY PROGRESSIVE WITH CLOSED LOW JUST TO NORTH OF FA THROUGH EARLY SUNDAY MORNING. MOST PROMISING DYNAMICS AND PLENTY OF LOW LEVEL SHEAR AND INSTABILITY AHEAD OF MAIN SQALL LINE TO PRODUCE POTENTIAL SUPERCELL ACTIVITY LATE AFTERNOON SAT...WITH MORE OF A POSSIBLE SQUALL LINE EVENT IN THE MID AND LATE EVENING. HAVE GONE CATEGORICAL CHANCES FOR SATURDAY...WITH MORNING THUNDERSTORMS NOT AS LIKELY SEVERE...BUT SOME THREAT OF ISOLATED HEAVY RAIN IN THE SOUTHWEST. SFC WARM FNT APPROACHING FROM CENTRAL PLAINS BRINGING GOOD SHOT OF 70 TO LOW 70 DEWPOINTS ESPECIALLY IN THE WEST FOR SATURDAY. HAVE MENTION OF SEVERE IN GRIDS WITH DAMAGING WINDS GREATEST THREAT FROM ESPECIALLY 18-02Z. LINGERING CHANCE OF SHOWERS WITH A MENTION OF EARLY MORNING THUNDERSTORMS IN THE FAR EAST FOR SUNDAY...THEN CHANCE FOR SHRA IN THE NORTH IN WRAP AROUND THROUGH EARLY SUNDAY AFTERNOON. LONG TERM /MONDAY THROUGH FRIDAY/... EXTENDED FCST STARTING MON HAS HIGH PRESSURE BUILDING OVER OHVLY FROM THE MIDWEST AS LOW PRESSURE RETREATS FROM GTLKS REGION. EXPECT A GRADUAL WARMING OF THE AIRMASS THROUGH MIDWEEK AS A SFC LOW TRACKS INTO THE GTLKS WED. THIS WILL SEE A TRAILING COLD FRONT MOVE THROUGH OHVLY ON WED NITE AND THURS IN RESPONSE TO A STRONG AND PERSISTENTLY DEEPENING H5 TROF OVER THE ERN 1/2 OF CONUS. MILD AIR WILL SURGE AHEAD OF THE CDFNT...AND THE STRENGTHENING H5 L/W TROF WILL ALLOW FOR A STRONG PUSH OF COOL CONTINENTAL AIR INTO THE OHVLY ON NRLY FLOW AS STRONG SFC HIGH IN THE MIDWEST SETS UP. STRENGTH OF SYSTEM WED NITE AND THURS HAS ME INCREASE POPS AS THE FLOW AHEAD OF IT AND SIGNIFICANT HEIGHT FALLS BEHIND IT WOULD LIKELY SEE A LINE OF CONVECTION MOVE THROUGH THE REGION. COLD POOL SHOWERS POSSIBLE FOR REMAINDER OF THURS AND INTO FRI...BUT ONLY HAVE 20% POSSIBILITY HERE BEING THE LAST DAY OF FCST. TEMPS WERE GENERALLY BUMPED UP AHEAD OF WED NITE FRONT AND DROPPED BEHIND IT...NOT TOO FAR FROM MEX GUID. FRANKS && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 315 AM CDT SAT SEP 23 2006 .DISCUSSION... SURFACE COLD FRONT HAS ESSENTIALLY CAUGHT UP WITH THE DRYLINE...AND CURRENTLY EXTENDS FROM SW MO TO TULSA AND SW INTO SCNTRL OK. STRONG/SEVERE STORMS CONTINUE IN THE HIGHER CAPE AIR ACROSS FAR ERN OK AND NW AR...WITH ADDITIONAL CONVECTIVE DEVELOPMENT NOW OCCURRING ALONG THE FRONTAL BOUNDARY FROM CNTRL INTO NE OK. STRONG FORCING AND MOISTURE CONVERGENCE WILL ALLOW FOR CONTINUED DEVELOPMENT ALONG THE COLD FRONT OVER THE NEXT SEVERAL HOURS. GIVEN THE VERY STRONG SHEAR (0-6KM BULK SHEAR OVER 60 KTS) AND IMPRESSIVE MUCAPES (2000 J/KG) SEVERE WEATHER WILL BE POSSIBLE INTO THE EARLY MORNING HOURS. WILL ALSO NEED TO KEEP A CLOSE EYE ON SE OK...WHERE SURFACE WINDS ARE LOCALLY BACKED IN THE VICINITY OF AN OUTFLOW BOUNDARY. WILL FOLLOW THE SLIGHTLY FASTER RUC/GFS IN THE NEAR TERM CONCERNING THE COLD FRONT TIMING. EXPECT SURFACE FRONT TO BE PUSHING INTO FAR NW AR AROUND 14-15Z...AND SHOULD BE CLOSE TO EXITING THE FORECAST AREA BY 18Z. HIGHEST POPS OBVIOUSLY NEEDED IN THE FIRST HALF OF THE PERIOD...BUT WILL TAKE A LAST LOOK AT RADAR BEFORE DECIDING ON FINAL NUMBERS. POSITIVE TILT UPPER TROF WILL BE SLOW TO MOVE THROUGH THE REGION. DEVELOPING LOW-LEVEL CAA AND DEEP CYCLONIC FLOW SHOULD ALLOW FOR LOW CLOUDS TO PUSH S INTO NE OK/NW AR LATE SATURDAY NIGHT OR EARLY SUNDAY MORNING. SHORT RANGE MODELS HAVE A DECENT HANDLE ON THIS SCENARIO...BUT GENERALLY FAVORED THE SLIGHTLY COOLER MET FOR HIGHS. COOL NIGHT FOR SUNDAY NIGHT...WITH GRADUALLY CLEARING SKIES AND DRY LOW-LEVEL AIR IN PLACE. GRADUAL WARMUP TO ENSUE EARLY NEXT WEEK IN THE DRIER NWLY FLOW ALOFT. 00Z GFS CONTINUES SLOWER TREND WITH NEXT FRONT...WHICH IS POISED TO MOVE THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY. TWEAKED TEMPERATURES A BIT IN THE EXTENDED...OTHERWISE NO CHANGES WHERE MADE. && .PRELIMINARY POINT TEMPS/POPS... TUL 78 52 73 49 / 40 10 10 10 FSM 81 55 72 50 / 70 30 10 10 MLC 81 52 74 48 / 60 20 10 10 BVO 77 49 72 43 / 30 10 10 10 FYV 76 50 67 42 / 80 20 10 10 BYV 75 48 66 46 / 80 20 10 10 MKO 78 50 71 48 / 60 10 10 10 MIO 75 52 71 46 / 50 10 10 10 F10 77 50 72 48 / 50 10 10 10 HHW 85 59 76 53 / 60 30 10 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM FORECASTER ID= 17 LONG TERM FORECASTER ID= 18 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 428 AM CDT SAT SEP 23 2006 .SHORT TERM (TODAY THROUGH SUNDAY)...MODELS CONTINUE TO SHOW A WEAK SHORT WAVE TROUGH MOVING OUT OF NORTHERN MEXICO INTO SOUTH TEXAS BY THIS AFTERNOON. WATER VAPOR IMAGERY/LATEST RUC MODEL ALSO INDICATES THIS ALONG WITH A WEAK UPPER LEVEL JET STREAK. WILL CONTINUE WITH LOW END CHANCE POPS FOR CONVECTIVE INITIATION ALONG THE SEABREEZE THIS AFTERNOON FOR THE NORTHERN INLAND COASTAL PLAINS AND SLIGHT CHANCE FOR SOUTHERN COASTAL PLAINS. WINDS WILL NOT BE QUITE AS STRONG AS YESTERDAY WITH BREEZY CONDITIONS EXPECTED FOR THE COASTAL PLAINS. MAIN EMPHASIS ON FORECAST WILL BE TONIGHT INTO FIRST HALF OF SUNDAY. GFS AND NAM INDICATED VERY STRONG LOW LEVEL CONVERGENCE AND MOISTURE POOLING IN ADVANCE OF THE COLD FRONT THAT WILL BE ENTERING THE NORTHERN COUNTIES AFTER MIDNIGHT. STRONG UPPER LEVEL DIVERGENCE IS ALSO INDICATED ACROSS THE NORTHERN COUNTIES TONIGHT INTO EARLY SUNDAY. THIS IS A REGION WHERE SATURATED SOILS EXIST FROM HEAVY RAIN THIS PAST SUNDAY. ONLY NEGATIVE FACTOR IS QUALITY OF MOISTURE DEPTH OVER THE REGION COMPARED TO THE LAST EVENT. WILL WORD LOCALLY HEAVY RAINFALL POSSIBLE LATE TONIGHT/EARLY SUNDAY AND ISSUE A SPECIAL WEATHER STATEMENT TO COVER INCREASED FLASH FLOOD THREAT. MODELS INDICATED STRONG INSTABILITY OVER THE REGION BUT THE MID LEVEL SHEAR IS ALMOST NON-EXISTENT. WITH WARM MID LEVEL TEMPERATURES...HAIL THREAT IS ALSO SLIM. COULD SEE ISOLATED PULSE SEVERE LATER TONIGHT BUT MAIN FOCUS WILL BE HEAVY RAIN THREAT. FRONT WILL ADVANCE THROUGH THE COASTAL BEND SUNDAY WITH RAIN CHANCES DIMINISHING IN THE AFTERNOON. WITH NORTH WINDS AND TEMPS IN THE LOWER TO MID 80S...WILL FEEL LIKE AUTUMN HAS ARRIVED IN SOUTH TEXAS. && .MARINE...THE STRONG LOW LEVEL JET IN PLACE OVER THE COASTAL BEND WILL SHIFT EAST BY THIS AFTERNOON. CONTINUED SCA FOR THE BAYS FOR TODAY...THE WINDS WILL BE STRONG THIS MORNING. THE PRESSURE GRADIENT WILL RELAX SOME BY THIS AFTERNOON BUT THE THERMAL GRADIENT SHOULD MAINTAIN SCA THROUGH THE AFTERNOON. SEAS WILL BE SLOW TO DIMINISH WHILE WINDS GO BELOW SCA DURING THE EVENING. EXTENDED THE SCA FOR THE GULF WATERS UNTIL 06Z SUNDAY. NUMEROUS SHOWERS/T-STORMS WILL MOVE INTO THE GULF WATERS IN ADVANCE OF THE COLD FRONT MOVING INTO SOUTH TEXAS EARLY SUNDAY MORNING. WINDS WILL SHIFT TO THE NORTHEAST AND INCREASE DURING THE AFTERNOON. && .AVIATION...STRATUS A BIT MORE WIDESPREAD ACROSS SOUTH TEXAS THIS MORNING. MVFR CONDS WILL EXIST THRU ABOUT 15Z ACROSS THE AREA. VFR CONDS ARE EXPECTED THRU THE AFTERNOON INTO THE EARLY EVENING HOURS. SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP IN ADVANCE OF A COLD FRONT MOVING SOUTH THRU CENTRAL TEXAS THIS EVENING. STORMS PRODUCING VERY HEAVY RAIN WILL LEAD TO IFR/LIFR CEILINGS/VSBYS FROM BEEVILLE TO COTULLA BETWEEN 03Z-06Z SUNDAY AND SPREAD SLOWLY SOUTH INTO THE SOUTHERN COASTAL BEND BY 12Z-15Z SUNDAY. STORMS WILL BE SLOW TO MOVE OUT BUT CONDS SHOULD IMPROVE BY LATE AFTERNOON TO VFR. && .LONG-TERM (SUNDAY NIGHT THROUGH FRIDAY)...RESIDUAL RAIN IS EXPECTED BEHIND THE COLD FRONT SUNDAY NIGHT THROUGH MON MORNING WITH POPS AND CLOUDS DECREASING FROM N TO S. DRIER AIRMASS/COLD AIR ADVECTION WILL FILTER ACROSS THE REGION THROUGH MONDAY. A STRONG OFFSHORE FLOW WILL CONTINUE INTO MONDAY BEFORE RELAXING AS HIGH PRESSURE SETTLES ACROSS THE REGION. BY MONDAY NIGHT/TUESDAY MORNING MIN TEMPS ARE EXPECTED TO BE IN THE UPPER 50S ACROSS THE NRN CWA TO 60S SRN CWA DUE TO LOWER DEWPOINTS...LIGHT WINDS AND GOOD RADIATIONAL COOLING UNDER CLR SKIES. SFC HIGH THEN SHIFTS E THROUGH TUE WITH AN ONSHORE FLOW RESUMING AND USHERING IN HIGHER DEWPOINTS AND WARMER TEMPS. MID AND UPPER LEVELS ARE PROGD TO REMAIN DRY THROUGH THE REMAINDER OF THE WEEK. THE GFS HAS BACKED OFF ON BRINGING A COLD FRONT THROUGH S TX ON THU WITH MORE OF A BACKDOOR FRONT BRIEFLY BACKING WINDS TO THE ENE. HOWEVER THE UPPER LEVEL PATTERN STILL LOOKS CONDUCIVE FOR BRINGING A COLD FRONT THRU THE AREA. THE GFS LATEST SOLN ALSO PROGS A MUCH DRIER AIRMASS WITH THIS SYSTEM. DUE TO UNCERTAINTY THIS FAR OUT...HAVE COMPROMISED WITH THE WIND DIRECTION AND AM INDICATING A WEAKER NE FLOW VS THE STRONG N FLOW IN PREVIOUS FCST. ALSO WILL CONTINUE WITH A SLIGHT CHC FOR NOW UNTIL CONFIDENCE INCREASES WITH LATER RUNS. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 94 78 82 66 86 / 10 50 70 20 20 VICTORIA 93 74 81 61 85 / 30 60 70 10 10 LAREDO 100 78 85 66 89 / 10 60 60 20 20 ALICE 97 76 84 64 87 / 20 50 70 20 20 ROCKPORT 92 80 83 69 86 / 20 40 70 20 20 COTULLA 98 73 84 63 88 / 10 80 60 10 10 KINGSVILLE 96 77 85 67 87 / 20 50 70 20 20 NAVY CORPUS 91 80 84 72 85 / 10 40 70 20 20 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 1 AM SUNDAY FOR THE FOLLOWING ZONES: COASTAL WATERS BAFFIN BAY TO PORT ARANSAS OUT 20 NM... COASTAL WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS BAFFIN BAY TO PORT ARANSAS 20 TO 60 NM...AND WATERS PORT ARANSAS TO MATAGORDA SHIP CHANNEL 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 5 PM SATURDAY FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS... AND BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O'CONNOR. && $$ TT/89...SHORT-TERM TE/81...LONG-TERM tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1216 AM CDT SAT SEP 23 2006 .OVERNIGHT AVIATION... ONLY CHANGES TO PREV 00Z TAF FCST WILL BE TO SLOW DOWN THE FRONT AND THUNDERSTORM CHANCES TO AFTER 12Z AT D/FW SITES...THEN BTWN 20- 01Z SAT AT KACT...AS CD FNT RMNS WELL UP INTO TX/OK PANHANDLES. THE CD FNT WON'T CATCH UP TO DRYLINE OVER NW SECTIONS UNTIL BTWM 09Z-12Z SAT...ABOUT THE TIME BETTER LIFT FROM HEIGHT FALLS ARRIVES. CD FNT MAY NOT MAKE IT THROUGH KACT UNTIL AFTER 00Z SUN. OTRW...WILL BRING IN VFR CIGS INTO KACT AS OF THIS ISSUANCE...WITH FOG SATL IR IMAGERY/OBS SHOWING FAST DEVELOPMENT ON 35-45KT LLJ. I'LL MAINTAIN AN ARRIVAL AT D/FW SITES BY 09Z. CIGS SHOULD RISE TO VFR LVLS OR SCT OUT OVR ALL TAF SITES BY 03Z SUNDAY...AS SFC HI BUILDS INTO ERN NM/W TX AND UPPER FLOW BECOMES MORE WLY ORIENTED. && .PREV DISCUSSION... /ISSUED 906 PM CDT FRI SEP 22 2006/ UPDATE... SEVERE CONVECTION CONTINUES TO DEVELOP IN MOIST/UNSTABLE AND STRONGLY SHEARED AIRMASS NORTH OF THE RED RIVER THIS EVENING... LIKELY IN RESPONSE TO INTENSIFYING LOW-LEVEL JET INCREASING MASS CONVERGENCE ALONG RETREATING DRYLINE. MODELS HAVE BEEN CONSISTENT ON BACKBUILDING THE AXIS OF SCATTERED THUNDERSTORMS ACROSS THE NORTH CENTRAL AND NORTHWEST PORTIONS OF THE FORECAST AREA THROUGH THE NIGHT...BUT VERY LITTLE CONVECTION HAS DEVELOPED THUS FAR SOUTH OF THE RED RIVER. WILL MAINTAIN STATUS QUO WITH THE CURRENT FIRST PERIOD POPS...AS DRYLINE AND ZONE OF STRONGEST CONVERGENCE WILL CONTINUE TO RETREAT NORTHWESTWARD IN RESPONSE TO MID-LEVEL SHORTWAVE TROUGH CURRENTLY APPROACHING SOUTHEAST COLORADO. OTHER ELEMENTS OF THE FORECAST APPEAR TO BE ON TRACK AS WELL THIS EVENING...AND ONLY MINOR ADJUSTMENTS WILL BE MADE TO DEWPOINT... WIND...AND CLOUD COVER GRIDS TO ACCOUNT FOR CURRENT TRENDS. UPDATED PRODUCTS WILL BE ISSUED SHORTLY. 65/DD AVIATION... AGREE WITH CWSU THAT CONVERGENCE HAS BEEN MINIMIZED ALONG DRYLINE THIS AFTN...BUT SHOULD INCREASE AS LOW LVL FLOW BECOMES MORE SSE/SELY THROUGH 04-05Z. HOWEVER...ELEVATED MIXED LAYER (CAP) SEEMS MORE STOUT S OF 580DM LINE WHICH PER RUC...XTNDS FROM KGYI...TO KDTO/KLUD...TO NEAR KRPH. THUS ONLY ISOLD SHRA/TSRA MNLY NW-NE OF D/FW TAF SITES THROUGH 08-10Z...WHEN COLD FRONT SHOULD START TO OVERTAKE DRYLINE TO THE NW AND INITIATE ELEVATED STORMS AS S/W OVER TX/OK PANHANDLES APPROACHES AND HEIGHTS FALL. WILL KEEP TIMING OF MVFR CIGS ARND SAME TIMES 06-07Z AT KACT...TO 09-10Z AT D/FW SITES...WITH VFR CONDS TIL THEN. LOOK FOR BEST PROBS TO OCCUR D/FW AREA 10Z-17Z TIME FRAME AS CD FNT APPROACHES AND FORCING GETS BETTER WITH LINEAR...ELEVATED ACTIVITY EARLY...BECMG MORE SFC-BASED BY 18Z/AFTR NEAR D/FW...THEN ARRIVING INTO KACT VCNTY BY 21Z/AFTR. CD FRONT ARRIVES ACRS D/FW FROM 19-21Z WITH WND SHIFT TO WNW/NW...THEN INTO KACT LIKELY AFTR 00Z SUN. PREV DISCUSSION... /ISSUED 305 PM CDT FRI SEP 22 2006/ DISCUSSION... NEXT LOBE OF ENERGY SWINGING AROUND UPPER LOW IN THE CENTRAL PLAINS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO NORTHERN PORTIONS OF THE CWA TONIGHT...AND SPREAD SOUTHEAST ACROSS THE REGION EARLY SATURDAY. MODELS HAVE BEEN CONSISTENT AND IN GENERAL AGREEMENT IN DEVELOPING PRECIP OVER NORTHERN PORTIONS TONIGHT...WITH A COLD FRONT MOVING THROUGH THE AREA LATE SATURDAY. RAINS WILL END IN SOUTHERN PORTIONS BY EARLY SUNDAY WITH TEMPERATURES BECOMING MORE MODERATE AS WE HEAD INTO THE FIRST FULL WEEK OF FALL. WEAK RIDGING TO BEGIN SUNDAY BUT THE PERSISTENT BROAD TROUGH OVER THE EASTERN HALF OF THE U.S. WILL SEND ANOTHER SHOT OF COLD AIR AND ENERGY SOUTHWARD MIDWEEK...WITH A FRONT AND RAIN MOVING THROUGH LATE WEDNESDAY AND THURSDAY. DESPITE THESE RAIN CHANCES...IT SHOULD BE A PLEASANT WEEK AS TEMPERATURES REMAIN MILD...QUITE A CHANGE FROM RECENT WEEKS. FWD WATCHES/WARNINGS/ADVISORIES... NONE. $$ && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /42/05 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1215 PM EDT SAT SEP 23 2006 .UPDATE... THE THREAT OF SEVERE WEATHER CONTINUES FOR LATE THIS AFTERNOON INTO THIS EVENING. 15Z SURFACE ANALYSIS SHOWS THE STRONGEST SURFACE PRESSURE FALLS EXTENDING FROM WESTERN TENNESSEE TO SOUTHWEST ILLINOIS ALONG THE WARM FRONT. THE TEMPERATURE AT PADUCAH KENTUCKY CLIMBED FROM 68 TO 75 IN TWO HOURS AS THE FRONT STARTED TO COME THROUGH. THE TREND OVER THE NEXT SEVERAL HOURS SHOULD BE FOR PRESSURE TO CONTINUE FALLING OVER SOUTHWEST ILLINOIS AND AHEAD OF THIS WARM FRONTAL BOUNDARY AS THIS FEATURE LIFTS NORTH. PRESSURE FALLS AT THE SURFACE WILL BE IN RESPONSE TO A STRONG SHORTWAVE MOVING THROUGH THE UPPER LEVEL TROUGH CURRENTLY SEEN ON WATER VAPOR OVER NEBRASKA AND KANSAS. THE UPPER LEVEL CLOSED CIRCULATION OVER EASTERN SOUTH DAKOTA IS STARTING TO OPEN AND THE WHOLE UPPER LEVEL TROUGH AXIS IS EXPECTED TO PIVOT AND MOVE EASTWARD. AT THE SURFACE...THE LOW OVER SOUTHERN ILLINOIS WILL TRACK NORTHEAST AHEAD OF THE SHORTWAVE WITH BOTH THE 12Z NAM AND RUC INDICATING A PATH FROM SOUTH BEND TO SOUTHERN LAKE HURON EARLY THIS EVENING. THIS TRACK WILL LIKELY BRING THE SURFACE WARM FRONT INTO EXTREME SOUTHEAST MICHIGAN WITH THUNDERSTORMS ACTIVITY ALSO POSSIBLE ALONG THE COLD FRONT WITH STRONG DYNAMICAL FORCING. A MODIFIED NAM SOUNDING AT DETROIT DURING THIS TIME WITH A SURFACE PARCEL OF 75/67 YIELDS 1200 J/KG OF CAPE WITH LITTLE IF ANY CONVECTIVE INHIBITION. TEMPERATURES NEAR THE OHIO BORDER ARE ALREADY IN THE LOW 70S WITH DEWPOINTS IN THE MID 60S. STRATUS HAS STARTED TO THIN BUT WILL EXPECT CLOUDS TO THICKEN AGAIN AS LOW LEVEL THETA-E ADVECTION INCREASES ACROSS SOUTHEAST MICHIGAN THIS AFTERNOON. ANY SHOWERS OR THUNDERSTORMS THAT DEVELOP ALONG THIS ADVECTION WILL LIKELY REMAIN ELEVATED WITH THE MOST FAVORABLE TIME FOR SEVERE STORMS STILL LATE THIS AFTERNOON INTO THIS EVENING. MODELS STILL GENERALLY IN AGREEMENT SHOWING STRONG OMEGA BETWEEN 21-00Z AS WELL AS A COUPLED UPPER LEVEL JET. IF STORMS ARE ABLE TO BECOME SURFACE BASED BY EARLY EVENING...SEVERE THREAT WILL BE FOCUSED SOUTH OF I-69 WITH STRONG WIND GUSTS AND TORNADOS CONTINUING TO BE THE MAIN THREAT. FORECAST GENERALLY ON TRACK AND HAVE RAISED POPS FOR EARLY AFTERNOON ACROSS OUR SOUTHERN COUNTIES. .PREV DISCUSSION...ISSUED 706 AM EDT SAT SEP 23 2006 AVIATION... LOW LEVEL MOISTURE ADVECTION OVERNIGHT HAS RESULTED IN WIDESPREAD IFR CEILINGS AND MVFR VISIBILITY ACROSS SOUTHERN MICHIGAN THIS MORNING. WITH THE ONSET OF DAYTIME HEATING...CONDITIONS WILL GRADUALLY IMPROVE TO VFR BY 18Z. A STRONG STORM SYSTEM OVER THE PLAINS AND MISSISSIPPI VALLEY REGION WILL MOVE EAST INTO THE GREAT LAKES TONIGHT. AN ASSOCIATED AREA OF LOW PRESSURE WILL MOVE FROM THE MISSISSIPPI VALLEY INTO SOUTHERN MICHIGAN THIS EVENING. THIS ALONG WITH THE APPROACH OF THE UPPER LEVEL LOW WILL TRIGGER WIDESPREAD SHOWERS AND THUNDERSTORMS AFTER 21Z. CONVECTION WILL SLOWLY LIFT NORTH ACROSS SOUTHEAST MICHIGAN BETWEEN 21Z AND 05Z. THE SHOWERS AND THUNDERSTORMS ARE EXPECTED TO LOWER CEILINGS BACK TO MVFR DURING THE EVENING. && SHORT TERM...TODAY AND TONIGHT ISSUED 352 AM EDT SAT SEP 23 2006 THE CURRENT WATER VAPOR IMAGE SHOWS A POSITIVELY TILTED LONG WAVE TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO THE SOUTHERN ROCKIES. THE 07Z SURFACE ANALYSIS SHOWS A LOW OVER MINNESOTA WITH AN OCCLUDED FRONT EXTENDING INTO THE SOUTHERN PLAINS. A WARM FRONT IS ALSO LOCATED ACROSS CENTRAL ILLINOIS AND INDIANA AND A SECONDARY SURFACE LOW IS LOCATED NEAR THE TEXAS/OKLAHOMA BORDER. SHORT WAVE ENERGY NEAR THE BASE OF THE LONG WAVE TROUGH OVER THE SOUTHERN ROCKIES IS FORECAST TO LIFT INTO THE MIDWEST TODAY AND PHASE WITH THE CLOSED LOW CURRENTLY OVER THE NORTHERN PLAINS. THE UPPER TROUGH AXIS IS THEN FORECAST TO SWING THROUGH THE GREAT LAKES REGION LATE TONIGHT. THE 00Z MODEL SUITE FORECAST STRONG UPPER LEVEL JET COUPLING DEVELOPING ACROSS THE SOUTHERN GREAT LAKES REGION LATE IN THE AFTERNOON AND PERSISTING THROUGH THE EVENING. THIS ALONG WITH THE MID LEVEL HEIGHT FALLS WILL LEAD TO WIDESPREAD SHOWERS AND THUNDERSTORMS THIS EVENING. THE 00Z MODEL SUITE STILL HAVE SOME DIFFERENCES IN TIMING AND TRACK OF THE ASSOCIATED SURFACE LOW NOW OVER TEXAS INTO THE SOUTHERN GREAT LAKES REGION TONIGHT. THE UKMET...WRFHEMI AND GLOBAL TAKE THE LOW JUST SOUTHEAST OF DETROIT OVERNIGHT AND FOCUS THE HIGHER INSTABILITY SOUTH OF THE STATE. THE NAM...AND TO SOME EXTEND THE GFS...TAKES THE LOW ACROSS SOUTHERN LOWER MI THIS EVENING. ALL OF THE 00Z MODEL SUITE HAD SOME INITIALIZATION PROBLEMS WITH THE HEIGHT FIELDS UPSTREAM. GIVEN THE STRONG UPPER JET COUPLING OVER THE SOUTHERN LAKES THIS EVENING...PREFER THE NAM SURFACE LOW TRACK. THE NAM ALSO HAD A GOOD HANDLE ON THE STRENGTH AND POSITION OF THE LOW AS OF 06Z. THE FORECAST AREA IS IN A SLIGHT RISK FOR SEVERE WEATHER TODAY...WHICH WILL BE MORE LIKELY THIS EVENING AS STRONGER MID LEVEL FORCING MOVES INTO THE REGION. GIVEN THE STRONGLY SHEARED ENVIRONMENT...0-6KM SHEAR OF 40-50 KNOTS...THE SEVERE POTENTIAL WILL RELY ON HOW MUCH INSTABILITY CAN BE REALIZED. THE EXTENSIVE STRATUS DECK ACROSS THE AREA THIS MORNING WILL LIFT INTO A BROKEN STRATO CU FIELD BY AFTERNOON. SO SUNSHINE WILL BE VERY LIMITED TODAY. IF AFTERNOON TEMPS REACH THE MID 70S...MODIFIED NAM SOUNDINGS WITH LOWER 60 DEWPOINTS SHOW 0-1KM MIXED LAYER CAPE APPROACHING 1000 J/KG. GIVEN THE 50-60KT MID LEVEL WINDS AND EXPECTED BACKED SURFACE FLOW AHEAD OF THE APPROACHING LOW...STORM TYPE IS EXPECTED TO BE SUPERCELLULAR WITH DAMAGING WINDS AND TORNADOES THE PRIMARY SEVERE WEATHER HAZARDS. SOME DRYER MID LEVEL AIR HAS MOVED ACROSS THE FORECAST AREA THIS MORNING IN THE WAKE OF LAST EVENINGS CONVECTION. THUS UNTIL THE STRONGER MID LEVEL FORCING ARRIVES AFTER 21Z...POPS WILL BE FAIRLY LOW THIS MORNING AND AFTERNOON. WEAK SHORT WAVES EMBEDDED WITHIN THE SOUTHWEST FLOW ALOFT AND INCREASING UPPER JET FORCING WILL SUPPORT ISOLATED TO SCATTERED POPS THROUGH 21Z. AN INCREASE IN 850MB THETA E LATE THIS MORNING AND AFTERNOON SHOULD ALSO SUPPORT SCATTERED CONVECTION ALONG AND SOUTH OF I-94 THROUGH THE AFTERNOON. LONG TERM...SUNDAY THROUGH FRIDAY SURFACE LOW WILL LIFT THROUGH THE LOWER GREAT LAKES AND UP THE ST LAWRENCE VALLEY ON SUNDAY...LEAVING SOME DEGREE OF TROUGHING BACK ACROSS THE CENTRAL GREAT LAKES. 00Z NAM REVERSED ITS EARLIER TREND AND IS NOT A BIT FASTER TAKING THE LOW OUT OF THE REGION...WITH THE GFS ALREADY FASTER AND CONTINUING TO ACCELERATE. WITH THE FASTER CONSENSUS AND OVERALL TREND...DO NOT NECESSARILY BUY THE SHARP SURFACE TROUGH THE NAM LINGERS ACROSS SOUTHEAST MICHIGAN. HOWEVER SOME DEGREE OF LOW-LEVEL CYCLONIC FLOW AND CONVERGENCE CAN BE EXPECTED WITH THE COLD ADVECTION BEHIND THE SYSTEM. WILL CARRY LIKELY POPS ACROSS LAKE HURON DURING THE MORNING...OTHERWISE SCATTERED SHRA DURING THE AFTERNOON WITH SOME DIURNAL ENHANCEMENT TO LAPSE RATES/INSTABILITY. NAM ALSO CONTINUES TO TREND TOWARD THE GFS SOLUTION WITH THE NEXT SHORTWAVE DIGGING OUT OF NORTHERN CANADA MONDAY/MONDAY NIGHT. WITH THE FASTER APPROACH AND STRONGER/MORE DEFINED SHORTWAVE...WE WILL NOT SEE AS MUCH OF A PROLONGED PERIOD OF COLD NORTHERLY FLOW. MIXED LAYER FLOW BACKS AROUND TO THE WEST/SOUTHWEST ON MONDAY...WITH THE LOW-LEVEL THERMAL TROUGH WEAKENING/SHIFTING DOWNSTREAM...LIMITING LAKE EFFECT POTENTIAL. HOWEVER THIS WILL BE OFFSET BY INCREASING SYNOPTIC LIFT AHEAD OF THE SHORTWAVE...WITH ENHANCED LOW-LEVEL CONVERGENCE ALONG THE SURFACE TROUGH. AM CONCERNED THAT THE GFS IS TOO STRONG WITH THE SHORTWAVE...AND CONSEQUENTLY DIVES IT TOO FAR SOUTHWEST ACROSS THE CENTRAL GREAT LAKES. CONSENSUS WOULD OTHERWISE SUPPORT PRECIP TO THE EAST ACROSS LAKE HURON/ONTARIO. IF THE STRONGER GFS SOLUTION PANS OUT...WOULD NEED TO CARRY A CHANCE SHRA LATE MONDAY/MONDAY NIGHT ACROSS SOUTHEAST MICHIGAN. AS IT STANDS MOISTURE MAY BE RATHER LIMITED...BUT WILL INCREASE SKY COVER MONDAY NIGHT. THEREFORE WILL ALSO RAISE MINS A COUPLE DEGREES WITH ADDITIONAL CLOUDS/WEAK WARM ADVECTION. ADDITIONAL DIFFERENCES DEVELOP WITH THE NEXT LONGWAVE SYSTEM THAT DIGS ACROSS THE PLAINS TUESDAY/WEDNESDAY AND AMPLIFIES ACROSS THE GREAT LAKES BY THURSDAY. 00Z GFS HAS TRENDED SLOWER WITH THIS SYSTEM CRESTING THE WESTERN RIDGE...AND AMPLIFIES IT FARTHER WEST...LEADING TO A MUCH SLOWER TIMING INTO THE GREAT LAKES. OTHER 12Z MODELS WERE PRETTY SIMILAR AND CONSISTENT WITH THE EVOLUTION OF THE SYSTEM. TEMPTED TO LEAVE THE FORECAST AS IS FOR NOW GIVEN THIS BREAK FROM CONTINUITY...TO SEE WHETHER THE NEXT RUN SETTLES DOWN ON A SIMILAR SOLUTION. A QUICK LOOK AT THE 00Z ECMWF SHOWS A SIMILAR TREND...MORE AMPLIFIED AND ABOUT 12 HOURS SLOWER THAN THE 12Z RUN. IT LOOKS LIKE THERE IS SOMETHING IN THE 00Z INITIALIZATION THAT BOTH THE GFS/ECMWF LATCHED ONTO TO AFFECT THEIR SOLUTIONS. WE WILL SEE IF THIS FEATURE HOLDS INTO THE 12Z RUNS...WHICH WOULD LEAD TO A SLOWER ONSET BUT MORE PROLONGED PERIOD OF POPS THROUGH THE END OF THE WEEK. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CONSIDINE LONG TERM....BRAVENDER AVIATION...CONSIDINE UPDATE...KEK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1143 AM EDT SAT SEP 23 2006 .UPDATE... THE MAIN CONCERN DEALS WITH THE POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON AND EVENING. THE CONVECTION ALONG THE OHIO VALLEY AND MIDDLE MISSISSIPPI VALLEY HAS LIMITED THE MOISTURE TRANSPORT INTO NORTHERN IN AND INTO SRN LOWER MI. 12Z RAOB FROM ILX SHOWS THIS WITH LIMITED MOISTURE IN THE 925MB TO 850 MB LAYER. CLOUDS COVERED MUCH OF THE AREA...LIMITING THE RATE OF DESTABILIZATION. AT THIS TIME...MSAS WAS SHOWING LIFTED INDEX VALUES DOWN TO -3 DEG C INTO SOUTHERN LOWER MI...THE RUC SOUNDING NEAR AZO HAS AROUND 100 J/KG CIN SO ANY CONVECTION FOR A FEW HOURS SHOULD REMAIN ELEVATED. THE PROFILER IN NORTHERN INDIANA SHOWS BACKING FLOW BELOW 2KM SUGGESTING THE NEXT WAS WAVE APPROACHES. PLENTY OF SHEAR EXISTS IN THE 0 TO 6 KM LAYER FROM THIS PROFILER WITH VALUES UP AROUND 60 KTS FOR ORGANIZED CONVECTION. THE WAVE OF LOW PRESSURE WAS DEVELOPING DOWN NEAR STL. THE LATEST DATA SUGGESTS THIS FEATURE WILL TRACK NORTHEAST THIS AFTERNOON AND THROUGH SOUTHERN LOWER MI THIS EVENING. THE LOW LEVEL JET IS SHOWN TO BE FOCUSED FURTHER SOUTH...GENERALLY SOUTH OF INTERSTATE 94 THIS AFTERNOON AND EVENING. THIS WOULD IMPLY A HIGH SEVERE WEATHER THREAT SOUTH OF AZO. HOWEVER...THE SURFACE BOUNDARY WILL BE LOCATED FROM NEAR AZO TO MOP LATER THIS AFTERNOON. SUFFICIENT INSTABILITY WILL BE PRESENT FOR CONVECTION...PERHAPS SURFACE BASED...FAVORABLE 0 TO 6 KM SHEAR IS PRESENT FOR ORGANIZED STORMS. THUS THE SEVERE WEATHER THREAT CONTINUES...AND APPEARS TO BE MAXIMIZED LATER THIS AFTERNOON WHEN THE SURFACE WAVE ARRIVES. HEAVY RAIN COULD BE AN ISSUE WITH THE SURFACE BOUNDARY AROUND FOR 3 TO 6 HRS THIS AFTERNOON AND EVENING COUPLED WITH A VERY MOIST AIRMASS IN PLACE AS THE WAVE ARRIVES. WILL UPDATE THE HAZARDOUS WEATHER OUTLOOK AND INCREASE THE HEAVY RAIN THREAT.. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MJS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1140 AM EDT SAT SEP 23 2006 .UPDATE... MAIN FCST ISSUE IS REDEVELOPMENT OF MORE WIDESPREAD RAIN THIS AFTN AND EVENING. WATER VAPOR IMAGERY/RUC ANALYSIS AND 12Z RAOBS SHOW THAT THE MIDLEVEL LOW OVER THE NRN PLAINS HAS WEAKENED OVER THE LAST 12-24HRS AND HAS OPENED UP. OVERALL TROF ORIENTATION IS ALSO MORE POSITIVELY TILTED. SHORTWAVE THAT WAS OVER CO/UT YESTERDAY IS NOW RACING NE THRU THE CNTRL PLAINS. AT THE SFC...LOW PRES CENTER OVER SRN MN CONTINUES TO FILL...LEAVING A BROAD LOW PRES TROF FROM SRN MN TO UPPER MI AND SE LAKE SUPERIOR. STIFF NE WINDS DOMINATE LAKE SUPERIOR JUST N OF SFC TROF (WINDS HAVE BEEN GUSTING TO GALE FORCE TOWARD THE APOSTLES AND DULUTH). FARTHER S...THERE IS BEGINNING TO BE SOME SFC RESPONSE DUE TO SHORTWAVE HEADING ACROSS CNTRL PLAINS WITH HINTS OF NEW LOW PRES DEVELOPING IN MO/WRN IL. DEVELOPING WEAK 3HR PRES FALLS IN THAT AREA ARE MORE TELLING. PCPN CONTINUES TO BE CONFINED MOSTLY ALONG THE 850MB TROF WHICH IS ESSENTIALLY COINCIDENT WITH SFC TROF. FOG WHICH BRIEFLY BECAME DENSE ACROSS THE S EARLIER THIS MORNING HAS THINNED. AS SHORTWAVE ENERGY CONTINUES TO RACE NE...STRENGTHENING MID/UPPER LEVEL QVECTOR CONVERGENCE WILL OVERSPREAD LOW-LEVEL FRONTOGENESIS. THIS IS DEPICTED BY 06Z GFS AND 12Z RUC/NAM. COUPLED FORCING SHOULD LEAD TO AN EXPANSION OF PCPN IN THE AFTN THRU THIS EVENING... FOCUSED ALONG 850MB TROF THAT WILL CONTINUE TO MOVE S. SOME MINOR TIMING ADJUSTMENTS WILL BE MADE TO GOING FCST...BUT IN GENERAL... GOING FCST HAS SITUATION COVERED QUITE WELL. WILL ADD A MENTION OF A SLIGHT CHC OF THUNDER ACROSS MUCH OF THE CNTRL/E THIS AFTN/EARLY EVENING AS RUC MLCAPE IS A FEW HUNDRED J/KG. MODIFIED FCST SOUNDINGS FOR SFC T/TD OF MID TO UPPER 60S/UPPER 50S YIELD SIMILAR SBCAPE NUMBERS. && .PREV DISCUSSION... ISSUED AT 255 AM EDT MAIN FORECAST CONCERNS ARE PRECIP TRENDS TODAY/TONIGHT AND THEN AGAIN SUN NIGHT/EARLY MONDAY. CURRENT WV IMAGERY SHOWING CLOSED LOW SPINNING OVER EASTERN SD. A WELL DEFINED S/WV ROTATING AROUND THE EASTERN PERIPHERY OF THE UPPER LOW IS CURRENTLY LIFTING NORTHEAST ACROSS NRN WI INTO UPPER MI. FORCING ALONG THE LEADING EDGE OF THE S/WV HAS BEEN ENOUGH TO TOUCH OFF A FEW BANDS OF SHRAS AND EVEN A FEW TSRAS WITH ONE CURRENTLY PASSING OVER THE OFFICE. EXPECT THE S/WV AND SHRAS TO LIFT NORTHEASTWARD THROUGH THE REMAINDER OF THE OVERNIGHT HOURS. AFTER S/WV PASSES AREA WILL BE LEFT IN A MOIST LOW LEVEL ENVIRONMENT WITH LITTLE IN THE WAY OF UPPER FORCING THROUGH MIDDAY. THE EXCEPTION WILL BE ACROSS LAKE SUPERIOR WHERE 85H FRONT SHOULD HELP FOCUS BETTER CHANCES OF RAIN DURING THE MORNING IN THAT AREA. ELSEWHERE...EXPECT AREAS OF DRIZZLE AND LOCALLY DENSE FOG THROUGH THE MORNING HOURS. BY THIS AFTERNOON...S/WV DROPPING SEWD OUT OF CENTRAL CANADA WILL KICK UPPER LOW OUT TO THE NORTHEAST. AS THIS OCCURS...SFC LOW WILL REDEVELOP OVER SOUTHERN LAKE MICHIGAN/LOWER MICHIGAN. FAIRLY STRONG MID/UPPER LEVEL QVECTOR CONVERGENCE WILL DEVELOP ACROSS MUCH OF UPPER MI DURING THE LATE AFTERNOON/EARLY EVENING AND WILL COINCIDE WITH STRONGEST LOW LEVEL FRONTOGENESIS IN NW QUADRANT OF SFC LOW. THUS...EXPECT AN EXPANDING SHIELD OF RAIN TO OVERSPREAD MUCH OF THE AREA DURING THE LATE AFTERNOON AND EVENING HOURS. ONLY EXCEPTION WILL BE UP IN THE KEWEENAW AND OVER PARTS OF LAKE SUPERIOR WHERE MAIN FORCING WILL REMAIN OFF TO THE SOUTH. EXPECT RAIN TO TAPER OFF FROM WEST TO EAST OVERNIGHT AS SFC LOW MOVES OFF TO THE EAST. GFS IS THE QUICKEST OF ALL THE MODELS WITH THE TIMING OF THE SFC LOW AND IS THE PREFERRED MODEL AS IT HAS BEEN THE MOST CONSISTENT. ALTHOUGH...OTHER MODELS ARE NOT SHOWING SIGNIFICANT DISAGREEMENTS. SOME SUN SHOULD RETURN ON SUNDAY WITH NEAR SEASONAL TEMPS AS SYSTEM CONTINUES TO DEPART TO THE EAST. NEXT QUICK MOVING S/WV WILL DROP SOUTHEASTWARD OUT OF CANADA SUN NIGHT/EARLY MONDAY. TREND IN BOTH GFS AND NAM IS TOWARDS A MORE AMPLIFIED TROF. WHILE MOISTURE WILL BE QUITE LIMITED...BASED ON CURRENT TRENDS WILL ADD A SLIGHT CHC POP FOR MUCH OF THE AREA FOR LATE SUN NIGHT/MONDAY AM AS THE S/WV AND SFC TROF SWING THROUGH THE AREA. WILL NOT MAKE ANY SIGNIFICANT CHANGES TO THE TUE THROUGH END OF THE WEEK FCST AT THIS TIME. HOWEVER...GFS IS NOW ALMOST 24 HOURS SLOWER WITH MIDWEEK UPPER TROF AND SFC FRONT MOVING THROUGH THE AREA SHOWING THE FEATURE MOVING THROUGH WED EVENING VS. TUE NIGHT. AS THIS IS THE FIRST RUN SHOWING THE TREND WILL AWAIT ONE MORE MODEL CYCLE BEFORE MAKING ADJUSTMENTS. OBVIOUSLY IF SLOWER SOLN PANS OUT TEMPS ON WED WILL NEED TO BE RAISED. BEHIND THE FRONT EXPECT A PRETTY DECENT COOL SHOT WITH 85H TEMPS FALLING INTO THE 0 TO -4 RANGE FOR THU/FRI. GFS MAY BE SHOWING A BIT OF ITS COOL BIAS BUT LAKE WEEK TEMPS MAY NEED TO BE TRENDED DOWN A FEW DEGREES FROM CURRENT FCST. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (UPDATE) MZ (PREV DISCUSSION) mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE GAYLORD MI 1030 AM EDT SAT SEP 23 2006 .UPDATE...LATEST SATELLITE/RUC ANALYSIS SHOWING STACKED NORTHERN PLAINS STORM SYSTEM BEGIN TO SHOW SIGNS OF OPENING UP AS SHORTWAVE ENERGY ROUNDS BASE OF TROUGH OVER THE SOUTHERN PLAINS. AT THE SURFACE...WEAK LOW PRESSURE BEGINNING TO DEVELOP ACROSS CENTRAL MISSOURI IN RESPONSE TO APPROACHING SHORTWAVE. LARGE AREA OF SHOWERS AND THUNDERSTORMS REMAINS ANCHORED ACROSS THE LOWER OHIO RIVER VALLEY WHERE REMNANT OUTFLOWS FROM OVERNIGHT CONVECTION HAS FOCUSED BEST MASS CONVERGENCE. ADDITIONAL LIGHTER SHOWERS DEVELOPING OVER NORTHERN ILLINOIS IN DEVELOPING DEFORMATION AXIS NORTH OF MISSOURI LOW. CLOSER TO HOME...LOW STRATUS DECK HAVING A HARD TIME MIXING OUT THIS MORNING BENEATH REMAINING NOCTURNAL INVERSION AND LATE SEPTEMBER SUN. FORECAST CONCERNS FOR THE REMAINDER OF THE DAY CENTER ON CLOUD COVERAGE AND PRECIPITATION CHANCES. EXPECT ENOUGH MIXING LATE THIS MORNING/EARLY AFTERNOON TO HELP SCOUR OUT SOME OF THE LOW CLOUDS GIVEN SHALLOW NATURE OF LOW LEVEL MOISTURE...PER 12Z KAPX SOUNDING. LATEST REGION VISIBLE SATELLITE IMAGERY ALREADY SHOWING SIGNS OF THIS WITH SOME CLEARING NOTED OVER CENTRAL LAKE MICHIGAN AND EASTERN WISCONSIN WITH SMALLER CLEAR PATCHES ROTATING ACROSS NORTHERN MICHIGAN. NOT EXPECTING A WHOLE LOT OF SUN BY ANY MEANS WITH MID AND HIGH LEVEL MOISTURE RAPIDLY APPROACHING FROM CENTRAL PLAINS DEVELOPING STORM SYSTEM. AS FOR PRECIPITATION...LOCAL RADAR SHOWING DRY CONDITIONS AT THIS TIME ACROSS THE AREA. WILL MAINTAIN CHANCE WORDING THROUGH EARLY AFTERNOON AS DECENT MOISTURE (12Z LOCAL SOUNDING HAD PWAT OF 0.90 INCHES) MAY HELP KICK OFF LIGHT RAIN SHOWERS. HOWEVER...AM EXPECTING MOST AREAS TO REMAIN DRY UNTIL BETTER SLUG OF MOISTURE APPROACHES FROM THE SOUTH THIS AFTERNOON. THUNDERSTORM POTENTIAL APPEARS MINIMAL GIVEN LACK OF SIGNIFICANT SOLAR ISOLATION AND WARM SECTOR REMAINING SOUTH OF THE REGION. ISOLATED ELEVATED CONVECTION IS POSSIBLE LATER THIS AFTERNOON OVER THE NORTHERN LOWER AS DYNAMICS INCREASE AHEAD OF APPROACHING SHORTWAVE. MEAGER MID LEVEL LAPSE RATES OF UNDER 6 C/KM WOULD ARGUE OTHERWISE BUT GIVEN OVERALL DYNAMICS OF SYSTEM WILL CONTINUE TO MENTION. SPC DAY 1 SEVERE OUTLOOK STILL HAS AREAS SOUTHEAST OF A LINE EXTENDING FROM HARRISVILLE TO CADILLAC HIGHLIGHTED IN SLIGHT RISK FOR LATE THIS AFTERNOON AND EVENING. OVERALL KINEMATICS OF SYSTEM RATHER IMPRESSIVE WITH 0-6KM BULK SHEAR VALUES OF 60-70KTS AND 500MB WINDSPEED APPROACHING 60-65KTS IN THIS AREA. THERMODYNAMICS LESS THAN FAVORABLE WITH MODIFIED SOUNDINGS SHOWING ONLY 200-500 J/KG ML CAPE USING A SURFACE PARCEL OF 71/57. WHILE ISOLATED SEVERE THREAT IS POSSIBLE GIVEN ABOVE KINEMATICS...FEEL LACK OF INSTABILITY WILL PREVENT SIGNIFICANT DEEP MOIST CONVECTION FROM TAPPING THESE WINDS. BEST CHANCE FOR SEVERE WEATHER APPEARS TO BE NEAR SAGINAW BAY IF WARM SECTOR CAN PUSH THAT FAR NORTH. MSB && .PREV DISCUSSION ISSUED AT 610 AM EDT SAT SEP 23 2006 SFC/RUC/SATELLITE/RADAR AND UPPER AIR ANALYSIS SHOWING STACKED LOW PRESSURE IN SRN MN WITH DEEP SOUTHERLY FLOW OVER NRN MI AND SEVERAL VORTICITY MAXIMA ROTATING AROUND THE SYSTEM/UPPER MIDWEST. AXIS OF HIGHEST H8-H7 THETA-E STRETCHES UP INTO NRN MICHIGAN BUT GREATEST MOISTURE LIES WELL SOUTH...INTO THE OHIO RIVER VALLEY. RADAR SHOWS FAIRLY QUIET WEATHER OVER NRN MICHIGAN AS AXIS OF H8-H7 FRONTOGENETICAL FORCING HAS SHIFTED NORTH...AND DRY SLOT HAS MOVED IN OVERHEAD. THIS HAS RESULTED IN COOLING OF THE LOW LEVELS PROMPTING THE DEVELOPMENT OF WIDESPREAD STRATUS AND LIGHT FOG. WE DO HAVE SOME SHOWERS AND ISOLATED STORMS THAT WERE MOVING NNE UP LAKE MICHIGAN IN A REGION OF STEEP H8-H5 LAPSE RATES OF 6.5 TO 7.0 C/KM ALONG A WEAKISH H8 LLJ OF 25 KTS AND H8 THETA-E GRADIENT. FURTHER UPSTREAM IN KANSAS/OKLAHOMA...ADDITIONAL SHORTWAVE ENERGY HAS PRODUCED LOW PRESSURE AND SHOWERY WEATHER. FORECAST CONCERNS...PRECIP TRENDS THROUGH SUNDAY AND POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON AND EVENING. WINDS OVER THE LAKES BECOME A CONCERN MAINLY BEGINNING SUNDAY AFTERNOON. TODAY AND TONIGHT...ALTHOUGH DRY SLOT HAS MOVED IN OVERHEAD...THE ATMOSPHERE IS STILL RATHER MOIST...AND WEAKISH H8 LLJ OF 20-25KTS AND STEEP MID LEVEL LAPSE RATES WILL RESULT IN ISOLATED THUNDERSTORMS WITH SCATTERED SHOWERS EARLY THIS MORNING ALONG WITH AREAS OF FOG. STILL REMAINS A TOUGH CALL FOR WHAT ENSUES FOR THE LATE MORNING THROUGH THE AFTERNOON...AS MODELS DIFFER ON SOME OF THE FINER DETAILS. HOWEVER...THE GENERAL IDEA REMAINS THE SAME. UPPER LOW IN MN OPENS UP AS A POSITIVELY TILTED WAVE AND EJECTS INTO INTO THE FAR WESTERN GREAT LAKES BY LATE THIS AFTERNOON. THE SFC LOW FROM OKLAHOMA DEEPENS FURTHER AND RIDES NE INTO CENTRAL LOWER BY 00Z. NAM-WRF NOT AS FAST WITH THIS EVOLUTION AS THE GFS (6HRS SLOWER)...AND SLIGHTLY FURTHER SOUTH THAN THE GFS...BUT DOES AGREE WITH THIS SOLUTION. AM TAKING A MIDDLE OF THE ROAD FORECAST HERE...AND AM EXPECTING A MOISTURE PUSH AND MASS CONVERGENCE TO ARRIVE LATE IN THE AFTERNOON PER ONGOING FORECAST WITH THE ARRIVAL OF THE SFC LOW. RAIN SHOWERS WILL BREAK OUT ACROSS NRN LOWER GENERALLY SOUTH OF M-32. UNTIL THEN...HAVE A FEELING THAT THINGS MAY BE RATHER QUIET...AS MID LEVEL LAPSE RATES BECOME LESS FAVORABLE THROUGH THE DAY WITH AN APPARENT LACK OF A LIFTING MECHANISM. HOWEVER...THE SHORTWAVES ROUNDING THE UPPER LOW ATTM...AND THE FACT THAT THE ATMOSPHERE IS SO MOIST KEEPS ME FROM TAKING OUT THE CHANCE FOR SHOWERS. AS FAR AS THUNDER AND SEVERE POTENTIAL...LOW CLOUDS AND FOG WILL CERTAINLY KEEP ANY INSTABILITY FROM DEVELOPING EARLY ON. MODELS SOUNDINGS DO NOT SUGGEST THAT THIS LOW LEVEL MOISTURE IS TOO DEEP...BUT MORNING 12Z UPPER AIR LAUNCH WILL TELL THE STORY. WITH AN EXPECTATION THAT THERE WILL BE AT LEAST SOME CLEARING BY AFTERNOON...AND MODIFYING SOUNDINGS FOR MLCAPE WITH A 71/57 PARCEL LEADS TO ONLY 200-500 J/KG. THIS IS NOT SO GREAT FOR DEEP CONVECTION. THEREFORE...EVEN THOUGH 0-6KM BULK SHEAR IS A WHOPPING 60-70KTS FOR THE AFTERNOON...THE ABSENCE OF DEEP CONVECTION WILL PREVENT SEVERE THUNDERSTORMS FROM OCCURRING. THE ONLY REAL CHANCE WOULD BE CONFINED TO THOSE AREAS CLOSEST TO THE SAGINAW BAY...IN ARENAC/GLADWIN COUNTIES SUCH AS PORTRAYED IN LATEST SPC DAY 1 OUTLOOK. WILL GO FOR SCATTERED THUNDERSTORMS HERE...OTHERWISE CAN ONLY SEE GOING WITH ISOLATED THUNDERSTORMS FOR THIS AFTERNOON AND FIRST HALF OF THE EVENING IN NRN LOWER DUE TO THE MINIMAL INSTABILITY. STORMS SHOULD BE MORE PREVALENT DOWNSTATE AND ACROSS THE LOWER MISSISSIPPI AND OHIO RIVER VALLEYS. THE SFC LOW PRESSURE WORKS ACROSS LOWER MICHIGAN TONIGHT AND CONTINUES TO DEEPEN. CONVERGENCE INCREASES FURTHER AS COLD FRONT SWEEPS ACROSS THE REGION OVERNIGHT. WRAP-AROUND MOISTURE IN MID LEVEL DEFORMATION ZONE WILL PRODUCE WHAT COULD BE UP TO AN INCH OF PRECIP ACROSS PORTIONS OF FAR NRN LOWER AND EASTERN UPPER MICHIGAN...BEFORE SWEEPING SE AND THROUGH THE SAGINAW BAY AREA MORE QUICKLY OVERNIGHT. HAVE INCREASED RAIN CHANCES TO CATEGORICAL FOR ALL AREAS TONIGHT. THERE MAY BE A BREAK IN THE ACTION ACROSS THE SAGINAW BAY REGION BETWEEN PRECIP FROM SFC LOW EARLY THIS EVENING AND WRAP-AROUND PRECIPITATION OVERNIGHT AS A DRY SLOT MAY TRY AND SNEAK IN FOR A PERIOD OF TIME. SUNDAY AND SUNDAY NIGHT...AT LEAST SCATTERED RAIN SHOWERS WILL STILL BE ONGOING ACROSS MAINLY NORTHEAST LOWER SUNDAY MORNING...BUT BY AFTERNOON THE SFC LOW PULLS FAR ENUF EAST THAT ALL MOISTURE AND FORCING IS DRAGGED AWAY FOR SOME CLEARING TO ENTER THE PICTURE. NAM-WRF WANTS TO KEEP SCATTERED SHOWERS IN FOR MOST OF THE AFTERNOON AND THIS PORTION OF THE FORECAST COULD SEE SOME TIMING DETAILS HAMMERED OUT IN SUBSEQUENT FORECAST ISSUANCES. THE MAIN WEATHER FOR THESE TIME PERIODS WILL BE THE COLD ADVECTION...INCREASED NORTHWEST WINDS AND OVER LAKE INSTABILITY THAT DEVELOPS. H8 TEMPS WILL HAVE FALLEN FROM 11C TO 1-3C BY SUNDAY AFTERNOON. HIGH TEMPERATURES WILL LIKELY ONLY GET TO THE MIDDLE 50S TO LOWER 60S WITH WINDS GUSTING TO AROUND 20 MPH AT TIMES IN THE AFTERNOON. OVER THE LAKES IT WILL BE A DIFFERENT STORY AS OVER LAKE INSTABILITY WILL BE AROUND THROUGH THE NIGHT DUE TO THE WARMER LAKE WATERS. WILL LIKELY SEE 20-30KT RANGE GUSTS...STRONGEST GUSTS WITH FROPA. TOO EARLY AT THIS TIME TO ISSUE SMALL CRAFT ADVISORIES...BUT FULLY EXPECT THEM IN ENSUING FORECASTS. WITH SUCH COLD H8 TEMPS COMING DOWN...HAVE TO CONSIDER LAKE EFFECT RAIN SHOWERS...HOWEVER THE AIR MASS LOOKS TO DRY TOO MUCH THROUGH SUNDAY EVENING...AND THERE COULD BE AS LITTLE AS JUST SCATTERED LAKE EFFECT CLOUDS. FOR THE OVERNIGHT HOURS...WE WILL HAVE A SECONDARY PUSH OF COLDER AIR/FRONT THAT THE NAM IS NOW JUMPING ON TO SOME EXTENT. 1000-850MB WINDS WILL BE MORE OUT OF THE WEST WITH DELTA T'S 13-14C. THIS DIRECTION MAY ALLOW WHITEFISH POINT TO GET CLIPPED WITH SOME WEAK LAKE EFFECT...BUT THIS WIND REGIME AFFECTS MORE OF NRN LOWER. WE MAY HAVE TO EVENTUALLY CONSIDER A CHANCE FOR RAIN SHOWERS BETWEEN GRAND TRAVERSE BAY AND THE STRAITS FOR LATE SUNDAY NIGHT AND POSSIBLY INTO MONDAY. NO OTHER CHANGES TO THE FORECAST. SMD && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE ALBANY NY 1037 AM EDT SAT SEP 23 2006 .SHORT TERM /REST OF TODAY/... THIS UPDATE IS BASED ON THE KENX AND NEIGHBORING RADAR TRENDS AS WELL AS THE LATEST 40KM RUC. THE MAIN THRUST OF THERMAL ADVECTION RAINFALL WITH THE THERMAL TROUGH IS CLEARING THE NE CORNER OF THE FCST AREAS /SRN VT AND THE LAKE GEORGE REGION/ AT THIS TIME. SCATTERED SHOWER ACTIVITY THAT HAS PERSISTED IN THE I-88 TO I-90 CORRIDOR IS TIED TO A WEAK H500 IMPULSE. WE HAVE DECIDED TO KEEP LIKELY VALUES FOR SHOWERS NORTH OF THE CAPITAL DISTRICT AND BERKSHIRES UP TO 18Z...THEN CHANCE VALUES THEREAFTER UP TO 22Z. WE ALSO WILL KEEP A CHANCE OF SHOWERS IN FOR THE NRN CATSKILLS...ERN MOHAWK VALLEY...CAPITAL DISTRICT AND BERKSHIRES UNTIL 18Z TOO. SLIGHT CHANCE VALUES SOUTH OF THE CAPITAL DISTRICT...WE WILL CONTINUE FROM THE LATE MORNING FORWARD. WE ALSO BUMPED MAX TEMPS DOWN A CATEGORY /3 DEGREES/ FOR THE BULK OF THE FCST AREA. TEMPS WILL BE STEADY OR RISE AFTER 22Z. THE MAIN WARM FRONT WITH AN EMBEDDED SHORTWAVE WILL MOVE N/NE INTO NY AND NEW ENGLAND AFTER 22Z WITH ELEVATED CONVECTION A GOOD POSSIBILITY WITH SHOWALTER VALUES OF -1 TO -3C AND MLCAPE VALUES OF 200-500 J/KG BASED ON THE GFS MODEL SOUNDINGS FOR THE OVERNIGHT PERIOD. UPDATE...WASULA && .PREV DISCUSSION... /ISSUED 327 AM EDT SAT SEP 23 2006/ SYNOPSIS... A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION THIS MORNING...BRINING SHOWERS. THEN A BREAK IN THE PRECIPITATION WILL OCCUR DURING THE AFTERNOON AND INTO THE EVENING...BEFORE THE NEXT BATCH OF RAIN ARRIVES LATE TONIGHT ASSOCIATED WITH A STRENGTHENING LOW PRESSURE SYSTEM MOVING NORTHEAST THROUGH THE CENTRAL GREAT LAKES. AS THE SURFACE LOW CONTINUES TO PROGRESS NORTHEASTWARD INTO SOUTHERN CANADA ON SUNDAY...A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL SWEEP THROUGH EASTERN NEW YORK AND WESTERN NEW ENGLAND DURING THE AFTERNOON. SHOWERS AND THUNDERSTORMS AND WINDY CONDITIONS WILL AFFECT MOST OF THE REGION AS THE FRONT MOVES THROUGH...WITH SOME THUNDERSTORMS POSSIBLY BECOMING SEVERE SOUTH AND EAST OF THE CAPITAL REGION. DRIER AND COOLER CONDITIONS WILL MOVE IN FOR EARLY NEXT WEEK. SHORT TERM /TODAY THROUGH MONDAY/... AN ACTIVE COUPLE DAYS OF WEATHER IN STORE...COMPLETE WITH RAIN...INCREASING HUMIDITY LEVELS...WARM TEMPS...THUNDERSTORMS AND WIND. WHILE THE ENTIRE WEEKEND WILL NOT BE A WASHOUT...THERE WILL BE A FEW DOSES OF INCLEMENT WEATHER. THIS MORNING...WARM ADVECTION/ISENTROPIC LIFT PRODUCING OCCASIONAL LIGHT SHOWERS ACROSS THE AREA. HOWEVER...THIS FORCING WILL LIFT NORTH OF THE AREA BY AFTN...LEAVING MAINLY DRY CONDITIONS FOR THE REST OF THE DAY INTO THE EVENING. THERE WILL STILL BE PLENTY OF CLOUDS AROUND...WITH A NOTICEABLE INCREASE IN DEWPOINTS. DUE TO CLOUD COVER...TEMPS WILL BE HELD DOWN JUST BELOW 70 IN THE VALLEYS TODAY. TONIGHT...WE WILL LIKELY REMAIN DRY UNTIL LATE EVENING/EARLY SUNDAY MORNING. THEN THE NEXT BATCH OF RAIN MOVES IN FROM THE SOUTH AND WEST ASSOCIATED WITH A SURGE OF ISENTROPIC LIFT TIED TO AN IMPRESSIVE DEEPENING SFC CYCLONE LIFTING NE THRU THE CENTRAL GREAT LAKES REGION. WILL ADD MENTION OF THUNDER...WITH SOME ELEVATED INSTABILITY SEEN ON FORECAST SOUNDINGS IN THE MID LEVELS. IT WILL BE MILD NIGHT...WITH CLOUDS/RAIN AND LOW LEVEL MOISTURE ASSOC WITH S/SW FLOW. SUNDAY WILL BE THE MOST ACTIVE AND CHANGEABLE DAY IN THE SHORT TERM. THE AFOREMENTIONED SFC CYCLONE IS FORECAST TO LIFT NE THRU SE ONTARIO AND SOUTHERN QUEBEC...WITH A TRAILING COLD FRONT BLASTING THRU EASTERN NEW YORK/WESTERN NEW ENG DURING THE EARLY TO MID AFTN. THERE ARE A COUPLE DIFFERENT CONCERNS. THE FIRST IS THE SEVERE THUNDERSTORM POTENTIAL. CHOSE TIMING CLOSEST TO THE GFS...WHICH BRINGS THE COLD FRONT THRU MUCH EARLIER THAN THE WRF/NAM. EARLY TO MID AFTN TIMING OF CFROPA WILL PLAY A BIG ROLE IN DETERMINING WHICH AREAS HAVE THE GREATEST SEVERE POTENTIAL. AS OF NOW IT APPEARS AREAS TO THE SOUTH AND EAST OF THE CAPITAL REGION WILL BE AT RISK. THIS IS WHERE THE MOST INSTABILITY WILL HAVE A CHANCE TO BUILD. FORECAST CAPE VALUES ARE MODEST AT BEST AROUND 300-500 J/KG...HOWEVER THERE WILL BE LOW LEVEL CONVERGENCE ALONG THE FRONT...TO GO ALONG WITH A VERY STRONG AND IMPRESSIVE WIND FIELD THROUGHOUT THE DEPTH OF THE TROPOSPHERE. THIS WILL LIKELY BE A HIGH SHEAR/LOW INSTABILITY EVENT...WITH THE POTENTIAL FOR DAMAGING WIND GUSTS. MAINLY UNIDIRECTIONAL 0-6 KM BULK SHEAR VALUES OF 40-55 KTS COME AS NO SURPRISE SINCE 850 MB WINDS ARE FORECAST TO BE AROUND 50 KTS...WITH 700 MB WINDS NEAR 65 KTS! ANOTHER FAVORABLE FACTOR WILL BE SFC DEWPOINTS RISING INTO THE MID TO UPPER 60S. THE OTHER CONCERN BESIDES SEVERE THUNDERSTORMS IS THE POTENTIAL FOR STRONG...GUSTY WEST TO NORTHWEST WIND BEHIND THE COLD FRONT. COLD AIR ADVECTION WILL LEAD TO STRONG MIXING WITH SOME BREAKS OF SUNSHINE LIKELY. WINDS GUSTS OF 40-50 MPH WILL BE POSSIBLE DURING THE LATTER HALF OF THE AFTN AND EARLY EVENING. WE MAY END UP NEEDING A WIND ADVISORY...BUT TOO EARLY TO ISSUE JUST YET. WILL CONTINUE TO MENTION THREAT IN HWO. ALSO POST CFROPA...TEMPS WILL SPIKE DUE TO THE MIXING AND NEAR DRY ADIABATIC LAPSE RATES FOR A FEW HOURS. THIS WILL ALLOW TEMPS TO RISE INTO THE MID TO UPPER 70S FROM ALBANY SOUTHWARD. THE THREAT OF RAIN WILL DIMINISH CONSIDERABLY BY EVENING...WITH NORTHWEST FLOW REGIME BECOMING ESTABLISHED. MONDAY WILL FEATURE DRY CONDITIONS WITH MUCH COOLER TEMPS. LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... NO CHANGES TO THE GOING FORECAST PAST MONDAY. AFTER A REINFORCING SHOT OF COOL AIR EARLY TUESDAY...HIGH PRESSURE WILL BUILD IN AND TAKE CONTROL OF THE WEATHER WED INTO THUR. IT APPEARS THE NEXT LOW PRESSURE SYSTEM WILL APPROACH THE AREA OF FRI...BRINGING THE NEXT SIGNIFICANT CHANCE OF RAIN. AVIATION... CEILINGS ARE FORECAST TO LOWER IN THE PREDAWN HOURS TO AROUND 3000 FEET MSL WHICH WILL RESULT IN MVFR OVER THE VALLEYS WITH AREAS OF IFR OVER THE HIGHER TERRAIN...WITH CEILINGS SLIGHTLY BELOW 2000 FEET MSL SHORTLY AFTER DAYBREAK AND VISIBILITY 4 TO 5 MILES IN RAIN SHOWERS. WINDS WILL GENERALLY BE FROM THE SOUTH 7 TO 14 KNOTS. THE LOW CLOUDS ARE LIKELY TO BECOME SCATTERED IN LATE AFTERNOON BUT WILL BECOME BROKEN AROUND 5000 FEET EARLY THIS EVENING ALONG WITH LIGHT FOG FORMING. THE OVERCAST WILL LOWER TO AROUND 1000 FEET BY LATER THIS EVENING WITH WIDESPREAD LIGHT FOG RESULTING IN WIDESPREAD IFR CONDITIONS OVER THE REGION TONIGHT...WITH WINDS AT THE SURFACE CALM OR NEARLY SO. FIRE WEATHER... CONDITIONS FOR IGNITION WILL CONTINUE TO BE UNFAVORABLE WITH SCATTERED SHOWERS MOVING INTO THE REGION IN THE PREDAWN HOURS. SEVERAL HOURS OF RAIN LATER THIS MORNING WILL RESULT IN HIGH FUEL MOISTURE. A BRIEF PERIOD OF PARTLY SUNNY WEATHER MAY OCCUR LATER THIS AFTERNOON WHILE THE REGION IS IN THE WARM SECTOR BUT CLOUDINESS IS EXPECTED TO INCREASE THIS EVENING WITH OVERNIGHT RH VALUES CLOSE TO 100 PERCENT IN WIDESPREAD LIGHT FOG. AS THE COLD FRONT APPROACHES AND PASSES THROUGH THE REGION ON SUNDAY THUNDERSTORMS ARE LIKELY TO DEVELOP AND BRING A THREAT OF CLOUD TO GROUND LIGHTNING ALTHOUGH HEAVY RAIN WITH THE STORMS SHOULD MINIMIZE THE THREAT OF FIRE. SOME DRYING OF GROUND FUELS MAY BE EXPECTED FOLLOWING THE FRONTAL PASSAGE WITH BRISK WESTERLY WINDS 10 TO 15 MPH...PARTLY SUNNY SKIES...AND AFTERNOON RH VALUES OF 40 TO 50 PERCENT. HYDROLOGY... NO HYDRO PROBLEMS EXPECTED ON THE RIVERS THE NEXT SEVERAL DAYS. A WARM FRONT WILL BRING A PERIOD OF LIGHT RAIN TO THE FORECAST AREA SATURDAY MORNING INTO THE EARLY AFTERNOON. RAINFALL AMOUNTS OVER THE HYDRO SERVICE AREA WILL BE A TENTH OF AN INCH TO A THIRD OF AN INCH TODAY. THE REGION WILL GET INTO A WARM SECTOR LATE SATURDAY AFTERNOON INTO SUNDAY MORNING. A COLD FRONT AND A STRONG SURFACE CYCLONE MOVING NORTH OF THE SAINT LAWRENCE RIVER VALLEY SUNDAY MORNING...WILL BRING SOME HEAVY SHOWERS AND THUNDERSTORMS TO THE REGION. STRONG MOISTURE CONVERGENCE AHEAD OF THE FRONT...COUPLED WITH DEWPOINTS IN THE 60S AND PRECIPITABLE WATER VALUES IN THE 1.50-2.00" RANGE WILL CAUSE SOME LOCALLY HEAVY DOWNPOURS...AND WITH THEM A POTENTIAL FOR FLOODING OF POORLY DRAINED ROADS AND PARKING AREAS. RAPID RISES TO NEAR BANKFULL MAY OCCUR ON SOME STREAMS. THE PASSAGE OF THE COLD FRONT WILL BE FOLLOWED BY COOLER AND DRIER WEATHER FOR THE FIRST FEW DAYS OF THE UPCOMING WEEK. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NY...NONE. VT...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 1023 AM EDT SAT SEP 23 2006 .SHORT TERM /TODAY/...TEMPS WARMING NICELY THIS MORNING WITH READINGS NEAR 80 DEGREES OVER THE COASTAL PLAIN AS OF 10 AM. AFTERNOON HIGHS IN THE MID/UPPER 80S LOOKS ON TRACK. HAVE INCREASED DEWPOINT GRIDS SLIGHTLY TO REFLECT CURRENT TRENDS. THE NAM...GFS AND RUC ALL INDICATE SOME PRECIP DEVELOPING THIS AFTERNOON MAINLY OVER SOUTHERN SECTIONS. THIS IS LIKELY A RESULT OF SOME SEA BREEZE DEVELOPMENT GIVEN STRONG INLAND HEATING. FORECAST SOUNDINGS INDICATE SOME DECENT INSTABILITY ACROSS THE AREA AS WELL SO WILL ADD A 20 POP FOR THIS AFTERNOON. REST OF FORECAST ON TRACK. && .AVIATION...INCREASED DEWPOINTS WITH SOUTHERLY FLOW LEADING TO MORE IN THE WAY OF CLOUDINESS TODAY. GENERALLY MID AND HIGH LEVEL CLOUDS...BUT SOME OCCASIONAL MVFR CEILINGS IN LOWER STRATOCUMULUS WILL BE AROUND OVER THE NEXT COUPLE OF HOURS. AFTER THAT...ANTICIPATE VFR CONDITIONS WITH BROKEN CEILINGS IN THE 5K RANGE. && .MARINE...STILL SEEING 4 TO 6 FT COMBINED SEAS WITH UP TO 13 SECOND WAVE PERIODS AS EASTERLY SWELL CONTINUES ON AREA WATERS. WILL UPDATE MARINE FCST TO REMOVE MORNING WORDING AND TWEAK WINDS A LITTLE...BUT OVERALL FCST REMAINS LARGELY UNCHANGED. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR AMZ152-154. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS AFTERNOON FOR AMZ150- 156-158. && $$ SHORT TERM...WINGENROTH LONG TERM...WINGENROTH AVIATION...COLLINS MARINE...COLLINS nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WILMINGTON NC 750 AM EDT SAT SEP 23 2006 .UPDATE... ADDED REQUIRED HEADLINES TO APPROPRIATE ZONES FOR HIGH RIP CURRENT RISK TODAY. ALSO ADDED SLIGHT CHANCE OF SHOWERS TO THE COASTAL WATERS EXCEPT N OF CAPE FEAR AND GIVEN CURRENT BUOY DATA...ADDED SMALL CRAFT EXERCISE CAUTION STATEMENT FOR TODAY. && .SHORT TERM /TODAY THROUGH MONDAY NIGHT/... SFC HIGH PRESSURE OVER NORTHEAST/MIDATL STATES WILL SINK SSE TODAY. REMAINDER OF THE BL WILL FOLLOW SUIT LEADING TO A DEEP LAYER OF WARM AND MOIST S TO SWRLY FLOW. AS SUCH A WARM AND MUGGY AFTERNOON IS EXPECTED THIS FIRST DAY OF FALL AND CU DEVEL SHOULD BE FAIRLY ROBUST. WEAK SHOWER ACTIVITY JUST OFFSHORE FROM WRN BRUNSWICK AND OFF OF SC....A COMBO OF WEAK LLJ AND CONV AXIS...WILL PROBABLY DIMINISH WITHIN A FEW HRS OF SUNRISE. THIS IDEA IS SUPPORTED BY THE RUC, WHICH HAS RECENTLY INITIALIZED WITH THE ACTIVITY PRETTY WELL. AND ALTHOUGH A LAST MINUTE DECISION TO INCLUDE THEM MAY BE MADE FOR NOW THEY WILL LIKELY ONLY MERIT A NOWCAST OR TWO...IF EVER MAKING IT ONSHORE THAT IS. WITH CONTINUED WARM AND MOIST ADVECTION OVERNIGHT EXPECT GRADUAL INC IN MIDLVL CLOUDS AND A MUGGY NIGHT. FLOW SHOULD BE PARALLEL ENOUGH TO THE COAST THAT IF OFFSHORE SHOWERS REDEVEL THEY SHOULD REMAIN OVER WATER. BL APPEARS TO STAY MIXED ENOUGH TO PRECLUDE MUCH FOG DEVEL EVEN IF THE MID CLOUDS STAY JUST TO OUR NW, WHICH IS A POSSIBILITY SINCE THE OVERALL EVOLUTION OF THE SUNDAY/MONDAY PATTERN APPEARS SLOWER THAN PREV THOUGHT. ACCORDINGLY...POPS HAVE BEEN TRIMMED SUNDAY TO SHOW SLOWER TIMING. MOST OF THE DAY SHOULD BE MUGGY WITH MORE ROBUSTLY INCREASING MID LVL CLOUDS. LATER IN THE AFTERNOON POPS WILL STILL BE RISING AS THE COLD FRONT NEARS...AND THE SEA BREEZE MAY EVEN MAKE A CONTRIBUTION ALTHOUGH THE SYNOPTIC FLOW WILL KEEP IT FROM MOVING INLAND VERY FAR OR VERY QUICKLY. IF THE GFS TIMING IS CORRECT THEN POPS SHOULD START RAMPING UP QUICKLY AOA 03Z MONDAY (MAYBE A BIT SOONER W) AS DEEP ASCENT OVERSPREADS THE AREA. THE ASCENT IS DEEP BUT NOT TERRIBLY STRONG SO MODERATE RAIN WILL BE POSSIBLE DUE TO A DEEP NEARLY SATURATED LAYER BUT ANY HEAVY RAIN SHOULD BE CONFINED TO LOCALIZED POCKETS OF CONVECTION. THE FRONT WILL PROGRESSING ACRS THE AREA AT THIS TIME AND SHOULD ROUGHLY PARALLEL THE COAST AND BE JUST OFFSHORE AOA 12Z MON. THE EASTERNMOST COUNTIES WILL HAVE A TOUGH TIME SHAKING RAIN CHANCES THROUGH MOST OF MONDAY. AS THE TROUGH THAT DROVE THE FRONT INTO THE AREA ALREADY BEGINS LIFTING OUT A POTENT SHORTWAVE LAGGING BEHIND WILL BEING TO MOVE IN FROM THE WEST. ACCORDING TO THE GFS THE TROP WILL BE FOLDING DOWN TO ABOUT 500MB OVER ATL BY MONDAY AFTERNOON WITH THIS FEATURE. THIS WILL RESULT IN FAIRLY STRONG VERTICAL MOTION OVER THE ERN CAROLINAS. MOST OF THIS STRONG ASCENT WILL BE OCCURRING OVER THE DEEP STABLE BL OVER WRN ZONES BUT COASTAL COUNTIES MAY STILL HAVE A SHALLOW ENOUGH STABLE LAYER FOR SOME ELEVATED MOISTURE AND INSTABILITY AND COULD SEE ANOTHER ROUND OF APPRECIABLE RAINFALL. SHOULD THE BOUNDARY BE JUST A BIT FARTHER TO THE EAST MOST OF THE RAIN WILL REMAIN OFFSHORE. TOO EARLY TO IRON OUT THE DETAILS. && .AVIATION... PROBLEMATICAL FORECAST THIS MORNING...ESPECIALLY AT FLO WHICH IS NOW EXPERIENCING VLIFR CONDITIONS FOR VSBY AND CIG. HAVE NO GOOD EXPLANATION WHY IT HAS GONE SO LOW HERE...NEITHER GUIDANCE NOR CLIMO NOR THE SYNOPTIC SITUATION WOULD SUGGEST THIS SCENARIO. REST OF THE TAFS ARE BEHAVING. RADAR HAS PATCHES OF LIGHT SHOWER ACTIVITY MOVING ASHORE BEFORE DISSIPATING SOUTH OF CAPE FEAR WHICH IS LEADING TO TEMPO MVFR FOR CIGS AT CRE AND MYR. PATCHY MVFR FOG ELSEWHERE THIS MORNING EXCEPT FOR ILM WHICH SEEMS TO LIE JUST OUTSIDE OF THE BEST MOISTURE TAP. && .MARINE... LONG PERIOD SWELL FROM DISTANT TROPICAL CYCLONE HELENE CONTINUES TO IMPACT THE COASTAL WATERS. SWELLS ABOUT 4 FT WITH A PERIOD OF 15 SECONDS OUT AT 41013 ACCORDING TO SPECTRAL PLOTS. WITH TIGHTENING SOUTHERLY GRADIENT OVER THE COASTAL WATERS WIND DRIVEN WAVES HAVE ALSO INCREASED...LEADING TO COMBINED SEAS OF 5 FT AT 41013 AND AROUND 4 FT CLOSER TO SHORE. BASED ON LATEST FROM TPC ON HELENE...EXPECT SIGNIFICANT CONTRIBUTION TO COMBINED SEAS FROM THE SWELL COMPONENT TO CONTINUE INTO THE WEEKEND...ALTHOUGH IT LOOKS LIKE WE HAVE ALREADY SEEN ITS PEAK. PRESENT SHADOWING EFFECT OF SWELL ENERGY FOR WATERS WEST OF CAPE FEAR DUE TO FRYING PAN SHOALS WILL BECOME LESS OF A FACTOR DURING THE DAY TODAY AS SWELL ENERGY DECREASES. WINDS AND SEAS WILL PICK UP AGAIN SUNDAY IN ADVANCE OF COLD FROPA SET FOR EARLY MONDAY. MAY SEE SCA CRITERIA MET FOR SEAS SUNDAY NIGHT IN THE OUTER REACHES OF OUR NC WATERS. STUCK WITH THE GFS FOR MOST OF THE FORECAST EXCEPT FOR THE FIRST COUPLE OF PERIOD. AS NOTED BY OPC...THE GFS IS SUPPORTED BY THE ECMWF AND BY THE LATEST HPC MEDIUM RANGE FORECASTER GUIDANCE. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...NONE. && $$ SHORT TERM...MBB/RJD AVIATION...REK MARINE...REK/RJD nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 312 PM EDT SAT SEP 23 2006 .SHORT TERM... TONIGHT AND SUNDAY TOTAL CONVECTIVE FAILURE CONTINUES THIS AFTERNOON AS EXPANSIVE STRATUS DECK CONTINUES TO SEVERELY LIMIT SOLAR INSOLATION AND DESTABILIZATION. 18Z OBJECTIVE RUC MESOANALYSIS SHOWING MLCAPE PRACTICALLY NIL ACROSS THE CWA. CONVECTIVE OUTFLOW AND ONGOING CONVECTION OVER THE LOWER OHIO VALLEY HAS ALSO DISRUPTED SOUTHERLY MOISTURE CONVEYOR. THIRDLY...WAVE OF LOW PRESSURE WHICH ALL MODEL GUIDANCE DEVELOPS ALONG FRONTAL BOUNDARY IS STILL NOWHERE TO BE FOUND PER 18Z MSAS ANALYSIS. HAND 12Z MESOANALYSIS SHOWED A LARGE CONVECTIVE BUBBLE HIGH OVER THE REGION IN WHICH LOW PRESSURE WAVE WAS FORECAST TO DEVELOP...WHICH HAS LIKELY INHIBITED ITS DEVELOPMENT THUS FAR. FOR TONIGHT...NO SHORT RANGE MODEL GUIDANCE HAS A DECENT HANDLE ON ONGOING COVERAGE OF PRECIPITATION. WILL SIMPLY USE EXTRAPOLATION OF OBSERVATIONAL DATA FOR THE FIRST PERIOD OF THE FORECAST. THIS MEANS A SLOWER FROPA THAN ANY MODEL INDICATES...AND MUCH LESS COVERAGE/QPF WRT RAIN. REMOVED ALL MENTION OF SEVERE WEATHER WITH EARLIER UPDATE AND THIS STILL LOOKS GOOD GIVEN TOTAL LACK OF THERMODYNAMICS. KINEMATICS ARE EXTREME...HOWEVER WITHOUT INSTABILITY NO ORGANIZED CONVECTIVE UPDRAFTS WILL FORM. WILL GO WITH LIKELY POPS FOR THIS EVENING...THEN TAPER TO CHANCE OVERNIGHT AS PRIMARY MOISTURE PLUME SHIFTS EAST AND OCCLUDED FRONT SLOWLY CROSSES THE CWA. ON SUNDAY OCCLUDED FRONT CONTINUES EAST OF THE CWA WITH MID LEVEL DRY SLOT BRIEFLY PUNCHING INTO THE CWA IN THE MORNING. SECONDARY FROPA ENTERS THE NW CORNER OF THE CWA DURING THE MORNING THEN SPREADS SE THROUGH THE AFTERNOON WITH ATTENDANT MID LEVEL WAVE PROVIDING WEAK LIFT. WILL RETAIN LOW CHANCE POPS CWA WIDE...WITH HIGHER CHANCE N/NW ZONES WHERE AIR BECOMES JUST COLD ENOUGH FOR A LIMITED LAKE EFFECT RESPONSE. && .LONG TERM... SUNDAY NIGHT THROUGH SATURDAY. GOING FORECAST APPEARS ON TRACK WITH LITTLE CHANGE...THOUGH CONCERN WITH FORECAST THU INTO SATURDAY WITH RESPECT TO POTENTIAL INSTABILITY SHOWERS. LATEST GFS APPEARS OVERDONE WITH HUDSON BAY VORTEX AT F84 PER COMPARE WITH ENSEMBLE MEMBERS. GFS CONTINUES AGRESSSIVE WITH NORTHERN STREAM DIVING A WAVE IN BASE OF MEAN TROF TO DEVELOP END OF WEEK CUTOFF OVER GREAT LAKES LATE THURSDAY/FRIDAY WITH ASSOCIATED M29C COLD POOL INTO CWA FRI/SAT. HOWEVER WITH GEM/ECMWF AND EVEN GFS FLATTENING WESTERN RIDGE WITH APPROACH OF GULF OF AK SYSTEM...HESITATE TO ADOPT GFS SOLUTION OVER GREAT LAKES AT THIS TIME. && .AVIATION... MAJOR OVERHAUL NECESSARY FROM PREVIOUS TAF ISSUANCE TO FOCUS MORE ON LOW CIGS THAN TSRA. CONVECTIVE FAILURE EVIDENT TODAY WITH LOW/MID LEVEL MOISTURE CONVEYOR EFFECTIVELY CUTOFF BY ONGOING CONVECTION AND OUTFLOWS OVER THE LOWER OHIO VALLEY. EXPANSIVE CLOUD COVER HAS ELIMINATED POTENTIAL INSTABILITY. ILL-FATED TEMPO TSRA GROUPS WHICH WERE ADDED 18 HOURS BEFORE THE EVENT HAVE BEEN REMOVED ALTOGETHER WITH NO CONVECTIVE MENTION AT ALL. MAIN FOCUS FOR 18Z TAFS REVOLVES AROUND LOW CIGS. LOW STRATUS LOCKED IN AND EXPANSIVE CIRRUS SHIELD IS PREVENTING MUCH SUNSHINE FROM PENETRATING TO STRATUS DECK. SEE LITTLE REASON WHY MVFR CIGS WONT CONTINUE THROUGH THE REST OF THE DAY. CIGS BECOME MORE UNCERTAIN TONIGHT FOLLOWING OCCLUDED FRONTAL PASSAGE. SOME SUGGESTION BY UPSTREAM TRENDS THAT CIGS WILL IMPROVE FOLLOWING FRONT...HOWEVER MODEL GUIDANCE WOULD SUGGEST A CONTINUATION OF LOW CIGS FOLLOWING FRONT. FOR NOW WILL GO WITH PERSISTENCE AND KEEP CIGS IN MVFR CATEGORY THROUGH THE END OF THE TAF PERIOD AND MONITOR UPSTREAM TRENDS FOR 00Z ISSUANCE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM/AVIATION...HITCHCOCK LONG TERM...MURPHY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 530 PM EDT SAT SEP 23 2006 .SHORT TERM... TONIGHT AND SUNDAY MAIN FCST ISSUES ARE REDEVELOPMENT OF MORE WIDESPREAD RAIN THIS EVENING AND THEN DIMINISHING TRENDS LATE TONIGHT/SUN MORNING. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW THAT THE MIDLEVEL LOW OVER THE NRN PLAINS YESTERDAY HAS WEAKENED AND OPENED UP WITH OVERALL TROF ORIENTATION POSITIVELY TILTED ACROSS THE CNTRL TO SW CONUS. SHORTWAVE THAT WAS OVER CO/UT YESTERDAY IS RACING NE INTO THE GREAT LAKES REGION. AT THE SFC...BROAD LOW PRES COVERS SE MN/WI/NW IL. A NEW LOW PRES CENTER HAS YET TO BECOME WELL-DEFINED IN RESPONSE TO THE SHORTWAVE APPROACHING THE GREAT LAKES. MEANWHILE...A SFC TROF CONTINUES TO SLOW SAG SE ACROSS UPPER MI. STIFF NE WINDS ARE OCCURRING N OF THE TROF ACROSS LAKE SUPERIOR...ESPECIALLY THE W PART WHERE WINDS HAVE BEEN GUSTING TO GALE FORCE AT TIMES. SCT TSRA... SOME PRODUCING SMALL HAIL...DEVELOPED ACROSS THE CNTRL/ERN FCST AREA THIS AFTN AS THERE WERE ENOUGH BREAKS IN THE CLOUD COVER TO INCREASE INSTABITY. MODIFIED LAPS SOUNDING EARLY THIS AFTN FOR SFC T/TD OF 70/59F INDICATED UPWARDS OF 1000J/KG. THERE IS LITTLE CHANGE TO PREVIOUS THINKING FOR TONIGHT/SUN. COUPLING OF THE INCREASING MID/UPPER LEVEL FORCING SHOWN BY QVECTOR CONVERGENCE OVERTOP LOW-LEVEL FRONTOGENESIS SHOULD CONTINUE TO LEAD TO AN EXPANSION OF PCPN ACROSS UPPER MI THIS EVENING. PCPN SHOULD BECOME FOCUSED ALONG 850MB TROF THAT IS MOVING S ACROSS UPPER MI. EXPECT TSRA OVER THE CNTRL/E TO END BY MID EVENING AS INSTABILITY DIMINISHES. PCPN SHOULD THEN END FAIRLY QUICKLY FROM NW TO SE LATE TONIGHT THRU EARLY SUN MORNING AS SYSTEM IS PROGRESSIVE. ON SUNDAY...EXPECT IMPROVING SKY CONDITION TO PARTLY SUNNY AS SUGGESTED BY RH TIME SECTIONS. ALSO VIS SATELLITE IMAGERY INDICATES AN INCREASING AREA OF MOSTLY SUNNY SKIES TO THE NW OF LAKE SUPERIOR... SUPPORTING THE IDEA OF DECREASING CLOUD COVER HERE DURING THE DAY. .LONG TERM... 00Z MON THROUGH 00Z SUNDAY... LATEST NAM/GFS GUIDANCE SHOWS TROUGH PASSING OVER THE NORTHERN HALF OF THE CWA EARLY MONDAY MORNING...KEPT IN SLIGHT CHANCE FOR PRECIP ON MONDAY MORNING WITH A BETTER CHANCE OVER EASTERN LAKE SUPERIOR...WOULDN'T BE SURPRISED IF MOST OF THE FA REMAINED DRY AS BEST FORCING REMAINS OVER LAKE SUPERIOR. TUESDAY LOOKS LIKE A NICE DAY AHEAD OF WEDNESDAY'S WEATHER. MAX TEMPS IN THE UPPER 60S AREN'T OUT OF THE QUESTION WITH SOUTHERLY WINDS/PARTLY CLOUDY SKIES. DECIDED TO KEEP FCST DRY...DESPITE THE NAM CREATING WARM FRONTAL PRECIP DURING THE DAY ON TUESDAY AS ONLY THE LATEST...12Z...RUN HAS ANY PRECIP OVER THE FA...THE BETTER CHANCE FOR RAIN IS ON WEDNESDAY...THE QUESTION IS NOT IF BUT WHEN. FRONTAL TIMING HAS BEEN TRICKY GIVEN LACK OF MODEL TO MODEL CONSISTENCY. THOUGH THE MODELS THEMSELVES HAVE BEEN PRETTY CONSISTENT...WITH THE EXCEPTION OF LAST NIGHTS GFS RUN...00Z...AS THIS RUN BROUGHT THE LOW DIRECTLY OVER LAKE SUPERIOR AROUND 00Z ON THURSDAY. WITH THAT SAID THE LAST TWO RUNS HAVE TRENDED NORTH WITH THE LOW TRACK AS WELL AS A STRONGER LOW PRESSURE CENTER...AND KEEPING THE LOW JUST NORTH OF THE LAKE BY 00Z THURSDAY. NOT TO BE OUTDONE...THE ECMWF HAS MAINTAINED A QUICKER SOLUTION...BRINGING THE LOW AND ASSOCIATED CLD FNT THROUGH AROUND 12Z WEDNESDAY. AS A RESULT...FRONTAL PASSAGE TIMING IS A COMPROMISE BETWEEN 12Z GFS/UKMET/ECMWF/HPC GUIDANCE. WENT WITH A FRONTAL PASSAGE AROUND 18Z. DID INCREASE POPS FOR WEDNESDAY AFTN TO 40. FUTURE SHIFTS...STILL TOO MUCH UNCERTAINTY TO GO SCATTERED/LIKELY. AHEAD OF THIS FRONT WINDS COULD INCREASE TO NEAR GALE FORCE OVER THE EAST HALF OF LAKE SUPERIOR...THEN MODEST WINDS BEHIND IT...15-25 KT...THEN TAPERING OFF ON THURSDAY. THINGS COOL OFF A BIT BEHIND WEDNESDAYS FRONTAL PASSAGE. WITH HIGHS ON THURSDAY PROBABLY ONLY GETTING IN THE LOW 50S. KEPT POST FRONTAL PRECIP IN FOR AREAS NEAR AND AROUND LAKE SUPERIOR. FROM THURSDAY NIGHT INTO FRIDAY MORNING...1000-700/850-700/1000-500 THICKNESS VALUES SUPPORT SNOW OR SOME TYPE OF MIXED PRECIP. BUT THE MOST IMPORTANT LOW LEVEL THICKNESS...1000-850MB IS STILL TOO WARM TO CONSIDER ADDING SNOW/MIX TO FCST. HIGH PRESSURE TRIES TO BUILD IN THURSDAY NIGHT/FRI MORNING...HOWEVER BOTH THE ECMWF/GFS DEVELOP SOME TYPE OF LOW PRESSURE SYSTEM OVER THE CENTRAL GREAT LAKES WHICH IS KEEPING THIS HIGH FROM BUILDING TO FAR TO THE WEST. THE LATEST ENSEMBLE FCST FOR THE FRI/SAT TIME FRAME...HAS UPPER LEVEL TROUGHING OVER THE GREAT LAKES AND A BROAD HIGH PRESSURE RIDGE OVER THE WEST EXTENDING INTO THE SOUTHERN PORTION OF THE YUKON TERRITORY. THIS SUPPORTS ECMWF/GFS GUIDANCE...THOUGH DUE TO UNCERTAINTY OPTED TO ONLY KEEP PRECIP IN CENTRAL AND EASTERN LAKE SUPERIOR AREAS THROUGH 12Z FRIDAY. JUST MINOR CHANGES MADE TO TEMP/DWPT FCSTS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON(SHORT TERM)/PEARSON(LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 340 PM EDT SAT SEP 23 2006 .SHORT TERM DISCUSSION...19Z SATELLITE/SURFACE/AND RUC ANALYSIS INDICATING VERTICALLY STACKED LOW OVER SOUTHWEST MINNESOTA BEGINNING TO OPEN UP AND EJECT EAST AS 120+ KNOT 300MB JET STREAK AND SHORTWAVE ROUNDS BASE OFF TROUGH. AT THE SURFACE...1001MB LOW CENTERED OVER WEST CENTRAL WISCONSIN WITH A SECONDARY WAVE OF LOW PRESSURE RIDING UP FRONTAL ZONE IN MISSOURI. ILL DEFINED WARM FRONT STRETCHES EAST/WEST FROM ALPENA TO TRAVERSE CITY. REGIONAL RADARS SHOWING EXPANDING AREA OF SHOWERS MOVING NORTHEAST ACROSS CENTRAL LAKE MICHIGAN INTO NORTHERN ILLINOIS IN REGION OF INCREASING MID LEVEL DEFORMATION. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OCCURING ACROSS THE CENTRAL AND WESTERN U.P. AND PARTS OF THE NORTHERN LOWER WHERE AFTERNOON CLEARING HELPED GENERATE SOME SURFACE BASED INSTABILITY. FORECAST CONCERNS THROUGH SUNDAY CENTER ON PRECIPITATION TRENDS THROUGH EARLY SUNDAY AFTERNOON ALONG WITH INCREASING MARINE WINDS. TONIGHT...SHOWERS WILL CONTINUE TO SPREAD NORTH AND OVERSPREAD THE AREA THIS EVENING AS ISENTROPIC ASCENT INCREASES AHEAD OF PLAINS SYSTEM. ISOLATED THUNDER NOT OUT OF THE QUESTION THIS EVENING WITH LINGERING INSTABILITY GIVEN AFTERNOON CLEARING THAT OCCURRED ACROSS THE AREA. MODIFIED 12Z KAPX SOUNDING WITH A TEMPERATURE/DEWPOINT OF 68/58 RESPECTIVELY DOES SHOW NEARLY 850J/KG MEAN LAYER CAPE. ALTHOUGH KINEMATICS WILL BE ON THE INCREASE THIS EVENING WITH 0-6KM BULK SHEAR VALUES APPROACHING 60-70KTS AND 500MB WINDSPEED OF OVER 60KTS...AGREE WITH LATEST SPC DAY ONE OUTLOOK THAT KEEPS SEVERE THREAT JUST SOUTH OF THE AREA IN REGION OF BETTER SURFACE BASED INSTABILITY AND WHERE BEST MASS CONVERGENCE ON NOSE OF LOW LEVEL JET RESIDES. BY LATER TONIGHT...SURFACE WAVES OVER MISSOURI AND WISCONSIN CONGEAL TO ONE PRIMARY LOW CENTER. STILL SOME SUBTLE DIFFERENCES WITH OVERALL STRENGTH AND LOCATION OF LOW WITH GFS MOST AGGRESSIVE AND FASTEST SHOWING 992MB LOW NEAR GEORGIAN BAY BY 06Z. NAM LESS AGGRESSIVE SHOWING MORE DIFFUSE PRESSURE FIELD WITH 997MB LOW OVER SOUTHER LAKE HURON AT SAME TIME. UKMET OFFERS A NICE COMPROMISE WITH 995MB LOW OVER SOUTHERN LAKE HURON AND WILL SIDE WITH THIS SOLUTION. THIS PLACES MUCH OF THE NORTHWEST LOWER AND EASTERN U.P. IN DEFORMATION AXIS IN NORTHWEST QUADRANT OF SYSTEM. WILL HAVE CATEGORICAL COVERAGE OF SHOWERS IN THIS AREA. ELSEWHERE...NUMEROUS SHOWERS ARE EXPECTED AS SYSTEM PASSES THROUGH. SUNDAY...DEFORMATION AXIS QUICKLY PIVOTS OFF TO THE SOUTHEAST SUNDAY MORNING AND EARLY AFTERNOON AND WILL CONTINUE TO TAILOR POPS IN THIS FASHION. FORCING MOVES FAR ENOUGH EAST BY LATER SUNDAY AFTERNOON TO DRY OUT CONDITIONS. 850MB TEMPERATURES FALL THROUGHOUT THE DAY REACHING 1-2C BY MID AFTERNOON PRODUCING DELTA T/S OF 15C. HOWEVER...MID LEVELS QUICKLY DRY OUT WITH SIGNIFICANT INVERSION PRESENT AT 850MB. SO EXPECTING NOTHING MORE THAN SOME LAKE EFFECT CLOUDS TO STREAM OFF THE LAKES. CAA ADVECTION WILL KEEPS TEMPERATURES FROM RECOVERING MUCH WITH HIGHS EXPECTED ONLY IN THE UPPER 50S TO LOW 60S. MARINE...INCREASING OVER LAKE INSTABILITY AND TIGHTENING PRESSURE GRADIENT SHOULD LEAD TO SCA CRITERIA CONDITIONS BEGINNING SUNDAY MORNING AND CONTINUING THROUGH THE DAY FOR NEARSHORE WATERS OF NORTHERN LAKE MICHIGAN AND FROM 5 NM EAST OF THE MACKINAC BRIDGE TO STURGEON PT ALONG NORTHERN LAKE HURON. WILL HOIST SCA FOR THESE AREAS BEGINNING AT 9Z AND RUNNING THROUGH 21Z ON SUNDAY. MSB REMAINDER OF THE FORECAST (SUNDAY NIGHT THROUGH NEXT SATURDAY)...AS AUTUMN COMMENCES THERE WILL BE PLENTY OF SYSTEMS TO KEEP AN EYE ON WITH A FAST FLOW ALOFT. THE MAIN LONG TERM CONCERNS WILL BE POPS AND HIGH TEMPERATURES THROUGH THE PERIOD. SUNDAY NIGHT...DRY AIR (MEAN 900-700 MB RH UNDER 40 PERCENT) CONTINUES TO FILTER INTO THE REGION ALONG WITH ABUNDANT DOWNWARD MOTION BEHIND DEPARTING WAVE. THEREFORE DESPITE INCREASING OVER LAKE INSTABILITY (850 MB/LAKE DELTA TS BETWEEN 15 AND 18) WILL NOT INCLUDE POPS AS IT APPEARS THAT IT WILL BE TOO DRY TO PRODUCE NORTHWEST FLOW LAKE EFFECT RAIN SHOWERS. LOWS GENERALLY IN THE LOWER AND MIDDLE 40S EXPECTED. MONDAY...NORTHWEST FLOW ALOFT WITH 850 MB TEMPERATURES BETWEEN PLUS 2 AND 4 C WITH A SHORT WAVE MOVING THROUGH THE FLOW ACROSS SOUTHEAST ONTARIO. IT/S A CLOSE CALL AS TO HOW FAR SOUTH MOISTURE FROM THIS WAVE WILL BE WITH VARYING MODEL SOLUTIONS. FOR NOW WILL CONTINUE WITH FARTHER NORTH SCENARIO PER THE UKMET/NAM AND LIMIT LOW CHANCE POPS TO ACROSS CHIPPEWA COUNTY. HIGHS ARE EXPECTED TO BE IN THE LOWER AND MIDDLE 60S. MONDAY NIGHT AND TUESDAY...HEIGHTS SLOWLY RISE WITH WARMER AIR MOVING IN AT 850 MB (PLUS 8 TO PLUS 12 C). OVERALL PARTLY CLOUDY CONDITIONS EXPECTED WITH LOWS MONDAY NIGHT IN THE LOWER AND MIDDLE 40S AGAIN AND HIGHS TUESDAY IN THE MIDDLE 60S FOR THE MOST PART. WEDNESDAY AND THURSDAY...SOME TIMING ISSUES WITH THE NEXT IN THE SERIES OF SYSTEMS. MODEL TRENDS HAVE BEEN TO SLOW DOWN UPSTREAM SURFACE COLD FRONT. THEREFORE...HAVE LOWERED POPS TO LOW CHANCE ON WEDNESDAY AS WELL AS RAISE HIGHS WELL INTO THE 60S. HIGHER CHANCE POPS LOOK TO BE WEDNESDAY NIGHT (WITH THE FRONTAL PASSAGE) WITH CONTINUED CHANCE POPS ON THURSDAY DUE TO POSSIBLE LAKE EFFECT. FRIDAY AND SATURDAY...EXTENDED MODELS ARE HINTING AT THE DEVELOPMENT OF A COLD TROUGH AND ASSOCIATED SURFACE LOW DEVELOPMENT ACROSS THE EASTERN LAKES. FOR NOW WILL COOL DOWN TEMPERATURES INTO THE 50S FOR HIGHS BUT NOT ADD POPS JUST YET. INSTEAD WILL CONTINUE WITH CONTINUITY/OFFICE CONSENSUS BUT IF MODEL TRENDS CONTINUE POPS WILL LIKELY HAVE TO BE ADDED BY LATER SHIFTS. SULLIVAN && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 109 PM EDT SAT SEP 23 2006 .AVIATION... THUNDERSTORMS ARE EXPECTED TO HAVE AN IMPACT ON AVIATION OPERATIONS AT ALL TERMINALS OVER THE NEXT 12 HOURS. LOW CEILINGS WILL CONTINUE TO PREVAIL...DOING NO BETTER THAN MVFR THROUGH THIS TAF PERIOD. CONCERNING VISIBILITIES...A BRIEF PERIOD OF IMPROVEMENT WILL BE POSSIBLE THIS AFTERNOON...PRIOR TO THE ONSET OF WIDESPREAD CONVECTIVE ACTIVITY. THEREAFTER...LOW VISIBILITIES WILL PREVAIL...FLUCTUATING BETWEEN IFR AND MVFR...AND AS LOW AS LIFR IN THE VICINITY OF HEAVY DOWNPOURS IN THUNDERSTORMS. THE MAIN CHALLENGE IS TIMING BOTH THE ONSET AND DURATION OF THUNDERSTORM ACTIVITY. CANNOT COMPLETELY RULE OUT A HEAVY SHOWER OR ISOLATED THUNDERSTORM OVER THE NEXT COUPLE OF HOURS...BUT MAIN ACTIVITY WILL ARRIVE LATER IN THE DAY...SO SEE NO REASON TO DEVIATE FROM THE PREVIOUS TIMING OF THUNDERSTORM ACTIVITY...WITH THE MOST LIKELY PERIOD COINCIDING WITH THE MAXIMUM HEATING OF THE DAY. THIS TIMING WILL ALSO COINCIDE WITH MAX SURFACE CONVERGENCE AND MAX UPPER LEVEL DIVERGENCE WHICH WILL BE QUITE FAVORABLE FOR THUNDERSTORM ACTIVITY ACROSS SOUTHEAST LOWER MICHIGAN DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. FOLLOWING THE THUNDERSTORM ACTIVITY...LIGHT SHOWERS AND/OR DRIZZLE/FOG WILL BE POSSIBLE THROUGH THE EVENING HOURS...THUS WILL MAINTAIN LOW CEILINGS/VISIBILITIES. COOLER AIR WILL ALSO BEGIN TO FILTER INTO THE REGION...FURTHER EXTENDING THE PERIOD OF LOW CEILINGS. VISIBILITIES SHOULD IMPROVE TO VFR SHORTLY AFTER SUNRISE ON SUNDAY. && .PREV DISCUSSION...ISSUED 1215 PM EDT SAT SEP 23 2006 UPDATE... THE THREAT OF SEVERE WEATHER CONTINUES FOR LATE THIS AFTERNOON INTO THIS EVENING. 15Z SURFACE ANALYSIS SHOWS THE STRONGEST SURFACE PRESSURE FALLS EXTENDING FROM WESTERN TENNESSEE TO SOUTHWEST ILLINOIS ALONG THE WARM FRONT. THE TEMPERATURE AT PADUCAH KENTUCKY CLIMBED FROM 68 TO 75 IN TWO HOURS AS THE FRONT STARTED TO COME THROUGH. THE TREND OVER THE NEXT SEVERAL HOURS SHOULD BE FOR PRESSURE TO CONTINUE FALLING OVER SOUTHWEST ILLINOIS AND AHEAD OF THIS WARM FRONTAL BOUNDARY AS THIS FEATURE LIFTS NORTH. PRESSURE FALLS AT THE SURFACE WILL BE IN RESPONSE TO A STRONG SHORTWAVE MOVING THROUGH THE UPPER LEVEL TROUGH CURRENTLY SEEN ON WATER VAPOR OVER NEBRASKA AND KANSAS. THE UPPER LEVEL CLOSED CIRCULATION OVER EASTERN SOUTH DAKOTA IS STARTING TO OPEN AND THE WHOLE UPPER LEVEL TROUGH AXIS IS EXPECTED TO PIVOT AND MOVE EASTWARD. AT THE SURFACE...THE LOW OVER SOUTHERN ILLINOIS WILL TRACK NORTHEAST AHEAD OF THE SHORTWAVE WITH BOTH THE 12Z NAM AND RUC INDICATING A PATH FROM SOUTH BEND TO SOUTHERN LAKE HURON EARLY THIS EVENING. THIS TRACK WILL LIKELY BRING THE SURFACE WARM FRONT INTO EXTREME SOUTHEAST MICHIGAN WITH THUNDERSTORMS ACTIVITY ALSO POSSIBLE ALONG THE COLD FRONT WITH STRONG DYNAMICAL FORCING. A MODIFIED NAM SOUNDING AT DETROIT DURING THIS TIME WITH A SURFACE PARCEL OF 75/67 YIELDS 1200 J/KG OF CAPE WITH LITTLE IF ANY CONVECTIVE INHIBITION. TEMPERATURES NEAR THE OHIO BORDER ARE ALREADY IN THE LOW 70S WITH DEWPOINTS IN THE MID 60S. STRATUS HAS STARTED TO THIN BUT WILL EXPECT CLOUDS TO THICKEN AGAIN AS LOW LEVEL THETA-E ADVECTION INCREASES ACROSS SOUTHEAST MICHIGAN THIS AFTERNOON. ANY SHOWERS OR THUNDERSTORMS THAT DEVELOP ALONG THIS ADVECTION WILL LIKELY REMAIN ELEVATED WITH THE MOST FAVORABLE TIME FOR SEVERE STORMS STILL LATE THIS AFTERNOON INTO THIS EVENING. MODELS STILL GENERALLY IN AGREEMENT SHOWING STRONG OMEGA BETWEEN 21-00Z AS WELL AS A COUPLED UPPER LEVEL JET. IF STORMS ARE ABLE TO BECOME SURFACE BASED BY EARLY EVENING...SEVERE THREAT WILL BE FOCUSED SOUTH OF I-69 WITH STRONG WIND GUSTS AND TORNADOS CONTINUING TO BE THE MAIN THREAT. FORECAST GENERALLY ON TRACK AND HAVE RAISED POPS FOR EARLY AFTERNOON ACROSS OUR SOUTHERN COUNTIES. SHORT TERM...TODAY AND TONIGHT ISSUED 352 AM EDT SAT SEP 23 2006 THE CURRENT WATER VAPOR IMAGE SHOWS A POSITIVELY TILTED LONG WAVE TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO THE SOUTHERN ROCKIES. THE 07Z SURFACE ANALYSIS SHOWS A LOW OVER MINNESOTA WITH AN OCCLUDED FRONT EXTENDING INTO THE SOUTHERN PLAINS. A WARM FRONT IS ALSO LOCATED ACROSS CENTRAL ILLINOIS AND INDIANA AND A SECONDARY SURFACE LOW IS LOCATED NEAR THE TEXAS/OKLAHOMA BORDER. SHORT WAVE ENERGY NEAR THE BASE OF THE LONG WAVE TROUGH OVER THE SOUTHERN ROCKIES IS FORECAST TO LIFT INTO THE MIDWEST TODAY AND PHASE WITH THE CLOSED LOW CURRENTLY OVER THE NORTHERN PLAINS. THE UPPER TROUGH AXIS IS THEN FORECAST TO SWING THROUGH THE GREAT LAKES REGION LATE TONIGHT. THE 00Z MODEL SUITE FORECAST STRONG UPPER LEVEL JET COUPLING DEVELOPING ACROSS THE SOUTHERN GREAT LAKES REGION LATE IN THE AFTERNOON AND PERSISTING THROUGH THE EVENING. THIS ALONG WITH THE MID LEVEL HEIGHT FALLS WILL LEAD TO WIDESPREAD SHOWERS AND THUNDERSTORMS THIS EVENING. THE 00Z MODEL SUITE STILL HAVE SOME DIFFERENCES IN TIMING AND TRACK OF THE ASSOCIATED SURFACE LOW NOW OVER TEXAS INTO THE SOUTHERN GREAT LAKES REGION TONIGHT. THE UKMET...WRFHEMI AND GLOBAL TAKE THE LOW JUST SOUTHEAST OF DETROIT OVERNIGHT AND FOCUS THE HIGHER INSTABILITY SOUTH OF THE STATE. THE NAM...AND TO SOME EXTEND THE GFS...TAKES THE LOW ACROSS SOUTHERN LOWER MI THIS EVENING. ALL OF THE 00Z MODEL SUITE HAD SOME INITIALIZATION PROBLEMS WITH THE HEIGHT FIELDS UPSTREAM. GIVEN THE STRONG UPPER JET COUPLING OVER THE SOUTHERN LAKES THIS EVENING...PREFER THE NAM SURFACE LOW TRACK. THE NAM ALSO HAD A GOOD HANDLE ON THE STRENGTH AND POSITION OF THE LOW AS OF 06Z. THE FORECAST AREA IS IN A SLIGHT RISK FOR SEVERE WEATHER TODAY...WHICH WILL BE MORE LIKELY THIS EVENING AS STRONGER MID LEVEL FORCING MOVES INTO THE REGION. GIVEN THE STRONGLY SHEARED ENVIRONMENT...0-6KM SHEAR OF 40-50 KNOTS...THE SEVERE POTENTIAL WILL RELY ON HOW MUCH INSTABILITY CAN BE REALIZED. THE EXTENSIVE STRATUS DECK ACROSS THE AREA THIS MORNING WILL LIFT INTO A BROKEN STRATO CU FIELD BY AFTERNOON. SO SUNSHINE WILL BE VERY LIMITED TODAY. IF AFTERNOON TEMPS REACH THE MID 70S...MODIFIED NAM SOUNDINGS WITH LOWER 60 DEWPOINTS SHOW 0-1KM MIXED LAYER CAPE APPROACHING 1000 J/KG. GIVEN THE 50-60KT MID LEVEL WINDS AND EXPECTED BACKED SURFACE FLOW AHEAD OF THE APPROACHING LOW...STORM TYPE IS EXPECTED TO BE SUPERCELLULAR WITH DAMAGING WINDS AND TORNADOES THE PRIMARY SEVERE WEATHER HAZARDS. SOME DRYER MID LEVEL AIR HAS MOVED ACROSS THE FORECAST AREA THIS MORNING IN THE WAKE OF LAST EVENINGS CONVECTION. THUS UNTIL THE STRONGER MID LEVEL FORCING ARRIVES AFTER 21Z...POPS WILL BE FAIRLY LOW THIS MORNING AND AFTERNOON. WEAK SHORT WAVES EMBEDDED WITHIN THE SOUTHWEST FLOW ALOFT AND INCREASING UPPER JET FORCING WILL SUPPORT ISOLATED TO SCATTERED POPS THROUGH 21Z. AN INCREASE IN 850MB THETA E LATE THIS MORNING AND AFTERNOON SHOULD ALSO SUPPORT SCATTERED CONVECTION ALONG AND SOUTH OF I-94 THROUGH THE AFTERNOON. LONG TERM...SUNDAY THROUGH FRIDAY SURFACE LOW WILL LIFT THROUGH THE LOWER GREAT LAKES AND UP THE ST LAWRENCE VALLEY ON SUNDAY...LEAVING SOME DEGREE OF TROUGHING BACK ACROSS THE CENTRAL GREAT LAKES. 00Z NAM REVERSED ITS EARLIER TREND AND IS NOT A BIT FASTER TAKING THE LOW OUT OF THE REGION...WITH THE GFS ALREADY FASTER AND CONTINUING TO ACCELERATE. WITH THE FASTER CONSENSUS AND OVERALL TREND...DO NOT NECESSARILY BUY THE SHARP SURFACE TROUGH THE NAM LINGERS ACROSS SOUTHEAST MICHIGAN. HOWEVER SOME DEGREE OF LOW-LEVEL CYCLONIC FLOW AND CONVERGENCE CAN BE EXPECTED WITH THE COLD ADVECTION BEHIND THE SYSTEM. WILL CARRY LIKELY POPS ACROSS LAKE HURON DURING THE MORNING...OTHERWISE SCATTERED SHRA DURING THE AFTERNOON WITH SOME DIURNAL ENHANCEMENT TO LAPSE RATES/INSTABILITY. NAM ALSO CONTINUES TO TREND TOWARD THE GFS SOLUTION WITH THE NEXT SHORTWAVE DIGGING OUT OF NORTHERN CANADA MONDAY/MONDAY NIGHT. WITH THE FASTER APPROACH AND STRONGER/MORE DEFINED SHORTWAVE...WE WILL NOT SEE AS MUCH OF A PROLONGED PERIOD OF COLD NORTHERLY FLOW. MIXED LAYER FLOW BACKS AROUND TO THE WEST/SOUTHWEST ON MONDAY...WITH THE LOW-LEVEL THERMAL TROUGH WEAKENING/SHIFTING DOWNSTREAM...LIMITING LAKE EFFECT POTENTIAL. HOWEVER THIS WILL BE OFFSET BY INCREASING SYNOPTIC LIFT AHEAD OF THE SHORTWAVE...WITH ENHANCED LOW-LEVEL CONVERGENCE ALONG THE SURFACE TROUGH. AM CONCERNED THAT THE GFS IS TOO STRONG WITH THE SHORTWAVE...AND CONSEQUENTLY DIVES IT TOO FAR SOUTHWEST ACROSS THE CENTRAL GREAT LAKES. CONSENSUS WOULD OTHERWISE SUPPORT PRECIP TO THE EAST ACROSS LAKE HURON/ONTARIO. IF THE STRONGER GFS SOLUTION PANS OUT...WOULD NEED TO CARRY A CHANCE SHRA LATE MONDAY/MONDAY NIGHT ACROSS SOUTHEAST MICHIGAN. AS IT STANDS MOISTURE MAY BE RATHER LIMITED...BUT WILL INCREASE SKY COVER MONDAY NIGHT. THEREFORE WILL ALSO RAISE MINS A COUPLE DEGREES WITH ADDITIONAL CLOUDS/WEAK WARM ADVECTION. ADDITIONAL DIFFERENCES DEVELOP WITH THE NEXT LONGWAVE SYSTEM THAT DIGS ACROSS THE PLAINS TUESDAY/WEDNESDAY AND AMPLIFIES ACROSS THE GREAT LAKES BY THURSDAY. 00Z GFS HAS TRENDED SLOWER WITH THIS SYSTEM CRESTING THE WESTERN RIDGE...AND AMPLIFIES IT FARTHER WEST...LEADING TO A MUCH SLOWER TIMING INTO THE GREAT LAKES. OTHER 12Z MODELS WERE PRETTY SIMILAR AND CONSISTENT WITH THE EVOLUTION OF THE SYSTEM. TEMPTED TO LEAVE THE FORECAST AS IS FOR NOW GIVEN THIS BREAK FROM CONTINUITY...TO SEE WHETHER THE NEXT RUN SETTLES DOWN ON A SIMILAR SOLUTION. A QUICK LOOK AT THE 00Z ECMWF SHOWS A SIMILAR TREND...MORE AMPLIFIED AND ABOUT 12 HOURS SLOWER THAN THE 12Z RUN. IT LOOKS LIKE THERE IS SOMETHING IN THE 00Z INITIALIZATION THAT BOTH THE GFS/ECMWF LATCHED ONTO TO AFFECT THEIR SOLUTIONS. WE WILL SEE IF THIS FEATURE HOLDS INTO THE 12Z RUNS...WHICH WOULD LEAD TO A SLOWER ONSET BUT MORE PROLONGED PERIOD OF POPS THROUGH THE END OF THE WEEK. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CONSIDINE LONG TERM....BRAVENDER AVIATION...SHULER YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE ALBANY NY 1257 PM EDT SAT SEP 23 2006 CORRECTED HEADER .SHORT TERM /REST OF THIS AFTERNOON/... ANOTHER QUICK UPDATE TO IMPROVE THE ZONE FORECAST WORDING BASED ON THE 1730Z KENX RADAR. THE SHOWERS HAVE ENDED OVER THE MAJORITY OF THE FCST AREA WITH SOME LINGERING SHOWERS OVER THE SRN ADIRONDACKS. WE HAVE TAKEN THE POPS OUT PRIOR TO 22Z/6 PM SOUTH OF THE CAPITAL DISTRICT AND KEPT SLIGHT CHANCE OR LOW CHANCE VALUES IN FROM THE CAPITAL DISTRICT NORTH. THE MAIN WARM FRONT HAS REACHED WRN NY AND WRN PA. ANOTHER BATCH OF RAIN IS ORGANIZING OVER S-CNTRL PA AND MD FOR TONIGHT. SHORT TERM UPDATE...WASULA && .PREV DISCUSSION... /ISSUED 1037 AM EDT SAT SEP 23 2006/ SHORT TERM /REST OF TODAY/... THIS UPDATE IS BASED ON THE KENX AND NEIGHBORING RADAR TRENDS AS WELL AS THE LATEST 40KM RUC. THE MAIN THRUST OF THERMAL ADVECTION RAINFALL WITH THE THERMAL TROUGH IS CLEARING THE NE CORNER OF THE FCST AREAS /SRN VT AND THE LAKE GEORGE REGION/ AT THIS TIME. SCATTERED SHOWER ACTIVITY THAT HAS PERSISTED IN THE I-88 TO I-90 CORRIDOR IS TIED TO A WEAK H500 IMPULSE. WE HAVE DECIDED TO KEEP LIKELY VALUES FOR SHOWERS NORTH OF THE CAPITAL DISTRICT AND BERKSHIRES UP TO 18Z...THEN CHANCE VALUES THEREAFTER UP TO 22Z. WE ALSO WILL KEEP A CHANCE OF SHOWERS IN FOR THE NRN CATSKILLS...ERN MOHAWK VALLEY...CAPITAL DISTRICT AND BERKSHIRES UNTIL 18Z TOO. SLIGHT CHANCE VALUES SOUTH OF THE CAPITAL DISTRICT...WE WILL CONTINUE FROM THE LATE MORNING FORWARD. WE ALSO BUMPED MAX TEMPS DOWN A CATEGORY /3 DEGREES/ FOR THE BULK OF THE FCST AREA. TEMPS WILL BE STEADY OR RISE AFTER 22Z. THE MAIN WARM FRONT WITH AN EMBEDDED SHORTWAVE WILL MOVE N/NE INTO NY AND NEW ENGLAND AFTER 22Z WITH ELEVATED CONVECTION A GOOD POSSIBILITY WITH SHOWALTER VALUES OF -1 TO -3C AND MLCAPE VALUES OF 200-500 J/KG BASED ON THE GFS MODEL SOUNDINGS FOR THE OVERNIGHT PERIOD. UPDATE...WASULA PREV DISCUSSION... /ISSUED 327 AM EDT SAT SEP 23 2006/ SYNOPSIS... A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION THIS MORNING...BRINING SHOWERS. THEN A BREAK IN THE PRECIPITATION WILL OCCUR DURING THE AFTERNOON AND INTO THE EVENING...BEFORE THE NEXT BATCH OF RAIN ARRIVES LATE TONIGHT ASSOCIATED WITH A STRENGTHENING LOW PRESSURE SYSTEM MOVING NORTHEAST THROUGH THE CENTRAL GREAT LAKES. AS THE SURFACE LOW CONTINUES TO PROGRESS NORTHEASTWARD INTO SOUTHERN CANADA ON SUNDAY...A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL SWEEP THROUGH EASTERN NEW YORK AND WESTERN NEW ENGLAND DURING THE AFTERNOON. SHOWERS AND THUNDERSTORMS AND WINDY CONDITIONS WILL AFFECT MOST OF THE REGION AS THE FRONT MOVES THROUGH...WITH SOME THUNDERSTORMS POSSIBLY BECOMING SEVERE SOUTH AND EAST OF THE CAPITAL REGION. DRIER AND COOLER CONDITIONS WILL MOVE IN FOR EARLY NEXT WEEK. SHORT TERM /TODAY THROUGH MONDAY/... AN ACTIVE COUPLE DAYS OF WEATHER IN STORE...COMPLETE WITH RAIN...INCREASING HUMIDITY LEVELS...WARM TEMPS...THUNDERSTORMS AND WIND. WHILE THE ENTIRE WEEKEND WILL NOT BE A WASHOUT...THERE WILL BE A FEW DOSES OF INCLEMENT WEATHER. THIS MORNING...WARM ADVECTION/ISENTROPIC LIFT PRODUCING OCCASIONAL LIGHT SHOWERS ACROSS THE AREA. HOWEVER...THIS FORCING WILL LIFT NORTH OF THE AREA BY AFTN...LEAVING MAINLY DRY CONDITIONS FOR THE REST OF THE DAY INTO THE EVENING. THERE WILL STILL BE PLENTY OF CLOUDS AROUND...WITH A NOTICEABLE INCREASE IN DEWPOINTS. DUE TO CLOUD COVER...TEMPS WILL BE HELD DOWN JUST BELOW 70 IN THE VALLEYS TODAY. TONIGHT...WE WILL LIKELY REMAIN DRY UNTIL LATE EVENING/EARLY SUNDAY MORNING. THEN THE NEXT BATCH OF RAIN MOVES IN FROM THE SOUTH AND WEST ASSOCIATED WITH A SURGE OF ISENTROPIC LIFT TIED TO AN IMPRESSIVE DEEPENING SFC CYCLONE LIFTING NE THRU THE CENTRAL GREAT LAKES REGION. WILL ADD MENTION OF THUNDER...WITH SOME ELEVATED INSTABILITY SEEN ON FORECAST SOUNDINGS IN THE MID LEVELS. IT WILL BE MILD NIGHT...WITH CLOUDS/RAIN AND LOW LEVEL MOISTURE ASSOC WITH S/SW FLOW. SUNDAY WILL BE THE MOST ACTIVE AND CHANGEABLE DAY IN THE SHORT TERM. THE AFOREMENTIONED SFC CYCLONE IS FORECAST TO LIFT NE THRU SE ONTARIO AND SOUTHERN QUEBEC...WITH A TRAILING COLD FRONT BLASTING THRU EASTERN NEW YORK/WESTERN NEW ENG DURING THE EARLY TO MID AFTN. THERE ARE A COUPLE DIFFERENT CONCERNS. THE FIRST IS THE SEVERE THUNDERSTORM POTENTIAL. CHOSE TIMING CLOSEST TO THE GFS...WHICH BRINGS THE COLD FRONT THRU MUCH EARLIER THAN THE WRF/NAM. EARLY TO MID AFTN TIMING OF CFROPA WILL PLAY A BIG ROLE IN DETERMINING WHICH AREAS HAVE THE GREATEST SEVERE POTENTIAL. AS OF NOW IT APPEARS AREAS TO THE SOUTH AND EAST OF THE CAPITAL REGION WILL BE AT RISK. THIS IS WHERE THE MOST INSTABILITY WILL HAVE A CHANCE TO BUILD. FORECAST CAPE VALUES ARE MODEST AT BEST AROUND 300-500 J/KG...HOWEVER THERE WILL BE LOW LEVEL CONVERGENCE ALONG THE FRONT...TO GO ALONG WITH A VERY STRONG AND IMPRESSIVE WIND FIELD THROUGHOUT THE DEPTH OF THE TROPOSPHERE. THIS WILL LIKELY BE A HIGH SHEAR/LOW INSTABILITY EVENT...WITH THE POTENTIAL FOR DAMAGING WIND GUSTS. MAINLY UNIDIRECTIONAL 0-6 KM BULK SHEAR VALUES OF 40-55 KTS COME AS NO SURPRISE SINCE 850 MB WINDS ARE FORECAST TO BE AROUND 50 KTS...WITH 700 MB WINDS NEAR 65 KTS! ANOTHER FAVORABLE FACTOR WILL BE SFC DEWPOINTS RISING INTO THE MID TO UPPER 60S. THE OTHER CONCERN BESIDES SEVERE THUNDERSTORMS IS THE POTENTIAL FOR STRONG...GUSTY WEST TO NORTHWEST WIND BEHIND THE COLD FRONT. COLD AIR ADVECTION WILL LEAD TO STRONG MIXING WITH SOME BREAKS OF SUNSHINE LIKELY. WINDS GUSTS OF 40-50 MPH WILL BE POSSIBLE DURING THE LATTER HALF OF THE AFTN AND EARLY EVENING. WE MAY END UP NEEDING A WIND ADVISORY...BUT TOO EARLY TO ISSUE JUST YET. WILL CONTINUE TO MENTION THREAT IN HWO. ALSO POST CFROPA...TEMPS WILL SPIKE DUE TO THE MIXING AND NEAR DRY ADIABATIC LAPSE RATES FOR A FEW HOURS. THIS WILL ALLOW TEMPS TO RISE INTO THE MID TO UPPER 70S FROM ALBANY SOUTHWARD. THE THREAT OF RAIN WILL DIMINISH CONSIDERABLY BY EVENING...WITH NORTHWEST FLOW REGIME BECOMING ESTABLISHED. MONDAY WILL FEATURE DRY CONDITIONS WITH MUCH COOLER TEMPS. LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... NO CHANGES TO THE GOING FORECAST PAST MONDAY. AFTER A REINFORCING SHOT OF COOL AIR EARLY TUESDAY...HIGH PRESSURE WILL BUILD IN AND TAKE CONTROL OF THE WEATHER WED INTO THUR. IT APPEARS THE NEXT LOW PRESSURE SYSTEM WILL APPROACH THE AREA OF FRI...BRINGING THE NEXT SIGNIFICANT CHANCE OF RAIN. AVIATION... CEILINGS ARE FORECAST TO LOWER IN THE PREDAWN HOURS TO AROUND 3000 FEET MSL WHICH WILL RESULT IN MVFR OVER THE VALLEYS WITH AREAS OF IFR OVER THE HIGHER TERRAIN...WITH CEILINGS SLIGHTLY BELOW 2000 FEET MSL SHORTLY AFTER DAYBREAK AND VISIBILITY 4 TO 5 MILES IN RAIN SHOWERS. WINDS WILL GENERALLY BE FROM THE SOUTH 7 TO 14 KNOTS. THE LOW CLOUDS ARE LIKELY TO BECOME SCATTERED IN LATE AFTERNOON BUT WILL BECOME BROKEN AROUND 5000 FEET EARLY THIS EVENING ALONG WITH LIGHT FOG FORMING. THE OVERCAST WILL LOWER TO AROUND 1000 FEET BY LATER THIS EVENING WITH WIDESPREAD LIGHT FOG RESULTING IN WIDESPREAD IFR CONDITIONS OVER THE REGION TONIGHT...WITH WINDS AT THE SURFACE CALM OR NEARLY SO. FIRE WEATHER... CONDITIONS FOR IGNITION WILL CONTINUE TO BE UNFAVORABLE WITH SCATTERED SHOWERS MOVING INTO THE REGION IN THE PREDAWN HOURS. SEVERAL HOURS OF RAIN LATER THIS MORNING WILL RESULT IN HIGH FUEL MOISTURE. A BRIEF PERIOD OF PARTLY SUNNY WEATHER MAY OCCUR LATER THIS AFTERNOON WHILE THE REGION IS IN THE WARM SECTOR BUT CLOUDINESS IS EXPECTED TO INCREASE THIS EVENING WITH OVERNIGHT RH VALUES CLOSE TO 100 PERCENT IN WIDESPREAD LIGHT FOG. AS THE COLD FRONT APPROACHES AND PASSES THROUGH THE REGION ON SUNDAY THUNDERSTORMS ARE LIKELY TO DEVELOP AND BRING A THREAT OF CLOUD TO GROUND LIGHTNING ALTHOUGH HEAVY RAIN WITH THE STORMS SHOULD MINIMIZE THE THREAT OF FIRE. SOME DRYING OF GROUND FUELS MAY BE EXPECTED FOLLOWING THE FRONTAL PASSAGE WITH BRISK WESTERLY WINDS 10 TO 15 MPH...PARTLY SUNNY SKIES...AND AFTERNOON RH VALUES OF 40 TO 50 PERCENT. HYDROLOGY... NO HYDRO PROBLEMS EXPECTED ON THE RIVERS THE NEXT SEVERAL DAYS. A WARM FRONT WILL BRING A PERIOD OF LIGHT RAIN TO THE FORECAST AREA SATURDAY MORNING INTO THE EARLY AFTERNOON. RAINFALL AMOUNTS OVER THE HYDRO SERVICE AREA WILL BE A TENTH OF AN INCH TO A THIRD OF AN INCH TODAY. THE REGION WILL GET INTO A WARM SECTOR LATE SATURDAY AFTERNOON INTO SUNDAY MORNING. A COLD FRONT AND A STRONG SURFACE CYCLONE MOVING NORTH OF THE SAINT LAWRENCE RIVER VALLEY SUNDAY MORNING...WILL BRING SOME HEAVY SHOWERS AND THUNDERSTORMS TO THE REGION. STRONG MOISTURE CONVERGENCE AHEAD OF THE FRONT...COUPLED WITH DEWPOINTS IN THE 60S AND PRECIPITABLE WATER VALUES IN THE 1.50-2.00" RANGE WILL CAUSE SOME LOCALLY HEAVY DOWNPOURS...AND WITH THEM A POTENTIAL FOR FLOODING OF POORLY DRAINED ROADS AND PARKING AREAS. RAPID RISES TO NEAR BANKFULL MAY OCCUR ON SOME STREAMS. THE PASSAGE OF THE COLD FRONT WILL BE FOLLOWED BY COOLER AND DRIER WEATHER FOR THE FIRST FEW DAYS OF THE UPCOMING WEEK. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NY...NONE. VT...NONE. && $$ ny AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE ALBANY NY 1238 PM EDT SAT SEP 23 2006 .SHORT TERM /REST OF TONIGHT/... ANOTHER QUICK UPDATE TO IMPROVE THE ZONE FORECAST WORDING BASED ON THE 1730Z KENX RADAR. THE SHOWERS HAVE ENDED OVER THE MAJORITY OF THE FCST AREA WITH SOME LINGERING SHOWERS OVER THE SRN ADIRONDACKS. WE HAVE TAKEN THE POPS OUT PRIOR TO 22Z/6 PM SOUTH OF THE CAPITAL DISTRICT AND KEPT SLIGHT CHANCE OR LOW CHANCE VALUES IN FROM THE CAPITAL DISTRICT NORTH. THE MAIN WARM FRONT HAS REACHED WRN NY AND WRN PA. ANOTHER BATCH OF RAIN IS ORGANIZING OVER S-CNTRL PA AND MD FOR TONIGHT. SHORT TERM UPDATE...WASULA && .PREV DISCUSSION... /ISSUED 1037 AM EDT SAT SEP 23 2006/ SHORT TERM /REST OF TODAY/... THIS UPDATE IS BASED ON THE KENX AND NEIGHBORING RADAR TRENDS AS WELL AS THE LATEST 40KM RUC. THE MAIN THRUST OF THERMAL ADVECTION RAINFALL WITH THE THERMAL TROUGH IS CLEARING THE NE CORNER OF THE FCST AREAS /SRN VT AND THE LAKE GEORGE REGION/ AT THIS TIME. SCATTERED SHOWER ACTIVITY THAT HAS PERSISTED IN THE I-88 TO I-90 CORRIDOR IS TIED TO A WEAK H500 IMPULSE. WE HAVE DECIDED TO KEEP LIKELY VALUES FOR SHOWERS NORTH OF THE CAPITAL DISTRICT AND BERKSHIRES UP TO 18Z...THEN CHANCE VALUES THEREAFTER UP TO 22Z. WE ALSO WILL KEEP A CHANCE OF SHOWERS IN FOR THE NRN CATSKILLS...ERN MOHAWK VALLEY...CAPITAL DISTRICT AND BERKSHIRES UNTIL 18Z TOO. SLIGHT CHANCE VALUES SOUTH OF THE CAPITAL DISTRICT...WE WILL CONTINUE FROM THE LATE MORNING FORWARD. WE ALSO BUMPED MAX TEMPS DOWN A CATEGORY /3 DEGREES/ FOR THE BULK OF THE FCST AREA. TEMPS WILL BE STEADY OR RISE AFTER 22Z. THE MAIN WARM FRONT WITH AN EMBEDDED SHORTWAVE WILL MOVE N/NE INTO NY AND NEW ENGLAND AFTER 22Z WITH ELEVATED CONVECTION A GOOD POSSIBILITY WITH SHOWALTER VALUES OF -1 TO -3C AND MLCAPE VALUES OF 200-500 J/KG BASED ON THE GFS MODEL SOUNDINGS FOR THE OVERNIGHT PERIOD. UPDATE...WASULA PREV DISCUSSION... /ISSUED 327 AM EDT SAT SEP 23 2006/ SYNOPSIS... A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION THIS MORNING...BRINING SHOWERS. THEN A BREAK IN THE PRECIPITATION WILL OCCUR DURING THE AFTERNOON AND INTO THE EVENING...BEFORE THE NEXT BATCH OF RAIN ARRIVES LATE TONIGHT ASSOCIATED WITH A STRENGTHENING LOW PRESSURE SYSTEM MOVING NORTHEAST THROUGH THE CENTRAL GREAT LAKES. AS THE SURFACE LOW CONTINUES TO PROGRESS NORTHEASTWARD INTO SOUTHERN CANADA ON SUNDAY...A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL SWEEP THROUGH EASTERN NEW YORK AND WESTERN NEW ENGLAND DURING THE AFTERNOON. SHOWERS AND THUNDERSTORMS AND WINDY CONDITIONS WILL AFFECT MOST OF THE REGION AS THE FRONT MOVES THROUGH...WITH SOME THUNDERSTORMS POSSIBLY BECOMING SEVERE SOUTH AND EAST OF THE CAPITAL REGION. DRIER AND COOLER CONDITIONS WILL MOVE IN FOR EARLY NEXT WEEK. SHORT TERM /TODAY THROUGH MONDAY/... AN ACTIVE COUPLE DAYS OF WEATHER IN STORE...COMPLETE WITH RAIN...INCREASING HUMIDITY LEVELS...WARM TEMPS...THUNDERSTORMS AND WIND. WHILE THE ENTIRE WEEKEND WILL NOT BE A WASHOUT...THERE WILL BE A FEW DOSES OF INCLEMENT WEATHER. THIS MORNING...WARM ADVECTION/ISENTROPIC LIFT PRODUCING OCCASIONAL LIGHT SHOWERS ACROSS THE AREA. HOWEVER...THIS FORCING WILL LIFT NORTH OF THE AREA BY AFTN...LEAVING MAINLY DRY CONDITIONS FOR THE REST OF THE DAY INTO THE EVENING. THERE WILL STILL BE PLENTY OF CLOUDS AROUND...WITH A NOTICEABLE INCREASE IN DEWPOINTS. DUE TO CLOUD COVER...TEMPS WILL BE HELD DOWN JUST BELOW 70 IN THE VALLEYS TODAY. TONIGHT...WE WILL LIKELY REMAIN DRY UNTIL LATE EVENING/EARLY SUNDAY MORNING. THEN THE NEXT BATCH OF RAIN MOVES IN FROM THE SOUTH AND WEST ASSOCIATED WITH A SURGE OF ISENTROPIC LIFT TIED TO AN IMPRESSIVE DEEPENING SFC CYCLONE LIFTING NE THRU THE CENTRAL GREAT LAKES REGION. WILL ADD MENTION OF THUNDER...WITH SOME ELEVATED INSTABILITY SEEN ON FORECAST SOUNDINGS IN THE MID LEVELS. IT WILL BE MILD NIGHT...WITH CLOUDS/RAIN AND LOW LEVEL MOISTURE ASSOC WITH S/SW FLOW. SUNDAY WILL BE THE MOST ACTIVE AND CHANGEABLE DAY IN THE SHORT TERM. THE AFOREMENTIONED SFC CYCLONE IS FORECAST TO LIFT NE THRU SE ONTARIO AND SOUTHERN QUEBEC...WITH A TRAILING COLD FRONT BLASTING THRU EASTERN NEW YORK/WESTERN NEW ENG DURING THE EARLY TO MID AFTN. THERE ARE A COUPLE DIFFERENT CONCERNS. THE FIRST IS THE SEVERE THUNDERSTORM POTENTIAL. CHOSE TIMING CLOSEST TO THE GFS...WHICH BRINGS THE COLD FRONT THRU MUCH EARLIER THAN THE WRF/NAM. EARLY TO MID AFTN TIMING OF CFROPA WILL PLAY A BIG ROLE IN DETERMINING WHICH AREAS HAVE THE GREATEST SEVERE POTENTIAL. AS OF NOW IT APPEARS AREAS TO THE SOUTH AND EAST OF THE CAPITAL REGION WILL BE AT RISK. THIS IS WHERE THE MOST INSTABILITY WILL HAVE A CHANCE TO BUILD. FORECAST CAPE VALUES ARE MODEST AT BEST AROUND 300-500 J/KG...HOWEVER THERE WILL BE LOW LEVEL CONVERGENCE ALONG THE FRONT...TO GO ALONG WITH A VERY STRONG AND IMPRESSIVE WIND FIELD THROUGHOUT THE DEPTH OF THE TROPOSPHERE. THIS WILL LIKELY BE A HIGH SHEAR/LOW INSTABILITY EVENT...WITH THE POTENTIAL FOR DAMAGING WIND GUSTS. MAINLY UNIDIRECTIONAL 0-6 KM BULK SHEAR VALUES OF 40-55 KTS COME AS NO SURPRISE SINCE 850 MB WINDS ARE FORECAST TO BE AROUND 50 KTS...WITH 700 MB WINDS NEAR 65 KTS! ANOTHER FAVORABLE FACTOR WILL BE SFC DEWPOINTS RISING INTO THE MID TO UPPER 60S. THE OTHER CONCERN BESIDES SEVERE THUNDERSTORMS IS THE POTENTIAL FOR STRONG...GUSTY WEST TO NORTHWEST WIND BEHIND THE COLD FRONT. COLD AIR ADVECTION WILL LEAD TO STRONG MIXING WITH SOME BREAKS OF SUNSHINE LIKELY. WINDS GUSTS OF 40-50 MPH WILL BE POSSIBLE DURING THE LATTER HALF OF THE AFTN AND EARLY EVENING. WE MAY END UP NEEDING A WIND ADVISORY...BUT TOO EARLY TO ISSUE JUST YET. WILL CONTINUE TO MENTION THREAT IN HWO. ALSO POST CFROPA...TEMPS WILL SPIKE DUE TO THE MIXING AND NEAR DRY ADIABATIC LAPSE RATES FOR A FEW HOURS. THIS WILL ALLOW TEMPS TO RISE INTO THE MID TO UPPER 70S FROM ALBANY SOUTHWARD. THE THREAT OF RAIN WILL DIMINISH CONSIDERABLY BY EVENING...WITH NORTHWEST FLOW REGIME BECOMING ESTABLISHED. MONDAY WILL FEATURE DRY CONDITIONS WITH MUCH COOLER TEMPS. LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... NO CHANGES TO THE GOING FORECAST PAST MONDAY. AFTER A REINFORCING SHOT OF COOL AIR EARLY TUESDAY...HIGH PRESSURE WILL BUILD IN AND TAKE CONTROL OF THE WEATHER WED INTO THUR. IT APPEARS THE NEXT LOW PRESSURE SYSTEM WILL APPROACH THE AREA OF FRI...BRINGING THE NEXT SIGNIFICANT CHANCE OF RAIN. AVIATION... CEILINGS ARE FORECAST TO LOWER IN THE PREDAWN HOURS TO AROUND 3000 FEET MSL WHICH WILL RESULT IN MVFR OVER THE VALLEYS WITH AREAS OF IFR OVER THE HIGHER TERRAIN...WITH CEILINGS SLIGHTLY BELOW 2000 FEET MSL SHORTLY AFTER DAYBREAK AND VISIBILITY 4 TO 5 MILES IN RAIN SHOWERS. WINDS WILL GENERALLY BE FROM THE SOUTH 7 TO 14 KNOTS. THE LOW CLOUDS ARE LIKELY TO BECOME SCATTERED IN LATE AFTERNOON BUT WILL BECOME BROKEN AROUND 5000 FEET EARLY THIS EVENING ALONG WITH LIGHT FOG FORMING. THE OVERCAST WILL LOWER TO AROUND 1000 FEET BY LATER THIS EVENING WITH WIDESPREAD LIGHT FOG RESULTING IN WIDESPREAD IFR CONDITIONS OVER THE REGION TONIGHT...WITH WINDS AT THE SURFACE CALM OR NEARLY SO. FIRE WEATHER... CONDITIONS FOR IGNITION WILL CONTINUE TO BE UNFAVORABLE WITH SCATTERED SHOWERS MOVING INTO THE REGION IN THE PREDAWN HOURS. SEVERAL HOURS OF RAIN LATER THIS MORNING WILL RESULT IN HIGH FUEL MOISTURE. A BRIEF PERIOD OF PARTLY SUNNY WEATHER MAY OCCUR LATER THIS AFTERNOON WHILE THE REGION IS IN THE WARM SECTOR BUT CLOUDINESS IS EXPECTED TO INCREASE THIS EVENING WITH OVERNIGHT RH VALUES CLOSE TO 100 PERCENT IN WIDESPREAD LIGHT FOG. AS THE COLD FRONT APPROACHES AND PASSES THROUGH THE REGION ON SUNDAY THUNDERSTORMS ARE LIKELY TO DEVELOP AND BRING A THREAT OF CLOUD TO GROUND LIGHTNING ALTHOUGH HEAVY RAIN WITH THE STORMS SHOULD MINIMIZE THE THREAT OF FIRE. SOME DRYING OF GROUND FUELS MAY BE EXPECTED FOLLOWING THE FRONTAL PASSAGE WITH BRISK WESTERLY WINDS 10 TO 15 MPH...PARTLY SUNNY SKIES...AND AFTERNOON RH VALUES OF 40 TO 50 PERCENT. HYDROLOGY... NO HYDRO PROBLEMS EXPECTED ON THE RIVERS THE NEXT SEVERAL DAYS. A WARM FRONT WILL BRING A PERIOD OF LIGHT RAIN TO THE FORECAST AREA SATURDAY MORNING INTO THE EARLY AFTERNOON. RAINFALL AMOUNTS OVER THE HYDRO SERVICE AREA WILL BE A TENTH OF AN INCH TO A THIRD OF AN INCH TODAY. THE REGION WILL GET INTO A WARM SECTOR LATE SATURDAY AFTERNOON INTO SUNDAY MORNING. A COLD FRONT AND A STRONG SURFACE CYCLONE MOVING NORTH OF THE SAINT LAWRENCE RIVER VALLEY SUNDAY MORNING...WILL BRING SOME HEAVY SHOWERS AND THUNDERSTORMS TO THE REGION. STRONG MOISTURE CONVERGENCE AHEAD OF THE FRONT...COUPLED WITH DEWPOINTS IN THE 60S AND PRECIPITABLE WATER VALUES IN THE 1.50-2.00" RANGE WILL CAUSE SOME LOCALLY HEAVY DOWNPOURS...AND WITH THEM A POTENTIAL FOR FLOODING OF POORLY DRAINED ROADS AND PARKING AREAS. RAPID RISES TO NEAR BANKFULL MAY OCCUR ON SOME STREAMS. THE PASSAGE OF THE COLD FRONT WILL BE FOLLOWED BY COOLER AND DRIER WEATHER FOR THE FIRST FEW DAYS OF THE UPCOMING WEEK. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NY...NONE. VT...NONE. && $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 235 PM CDT SAT SEP 23 2006 .DISCUSSION...THE MAIN CONCERN IN THE SHORT TERM IS THE CONV POTENTIAL LATE TONIGHT INTO SUNDAY. ALTHOUGH BOTH THE NAM AND THE GFS ARE IN REASONABLE AGREEMENT ON THE OVERALL TIMING OF THE FRONT...BIG DIFFERENCES SHOW UP IN THE POPS AND OVERALL QPF VALUES. THE GFS QPF FIELDS LOOK TO HAVE SOME CONV FEEDBACK ISSUES THROUGH 12Z TOMORROW AND PAINT A LARGE CIRCULAR BULLSEYE OF VERY HIGH VALUES OVER THE CRP AND NORTHERN BRO CWAS. THIS LOOKS SOMEWHAT SUSPICIOUS AND AM FAVORING THE MORE CONSERVATIVE AND REASONABLE NAM FIELDS. THE HIGHER GFS QPF VALUES APPEAR TO BE DUE TO AN OVERDEVELOPED 500 MB VORT MAX MOVING OVER DEEP SOUTH TEXAS EARLY TOMORROW MORNING. THE GFS 500 MB VORTICITY FIELD EARLY IN THE PERIOD APPEARS TO BE THE OUTLIER IN COMPARISON TO THE RUC/NAM AND ECMWF SOLUTIONS WHICH INDICATE SOME PVA BUT BROADER AND WEAKER. ALTHOUGH THE GFS APPEARS TO BE TOO AGGRESSIVE IN OVERALL QPF FIELDS...THE ATMS IN PLACE OVER DEEP SOUTH IS VERY MOIST WITH A 12Z BRO PWAT OF AROUND 2.13 INCHES. WITH THE COLD FRONT APPROACHING THE REGION LATER TONIGHT AND SUNDAY...GOOD UVV WILL INTERACT WITH THIS DEEP MOISTURE TO SPREAD CONV OVER THE REGION ON SUNDAY. BECAUSE OF THE APPARENT CONV FEEDBACK PROBLEMS IN THE GFS...HAVE GONE WITH A BLEND OF THE MET AND MAV GUIDANCE FOR POPS IN THE SHORT TERM WITH THE RAIN CHCS DIMINISHING ON MONDAY AS DRIER AIR BUILDS INTO THE REGION. DUE TO THE HIGH PWATS THAT WILL PERSIST OVER THE REGION...WILL INCLUDE A MENTION OF LOCALLY HEAVY RAINFALL IN THE CURRENT ZFP WORDING AS THE LASTEST QPF OUTLOOKS FROM HPC PLACES ROUGHLY 1 TO 2 INCH AMOUNTS FOR TOTAL AREAL COVERAGE WITHIN THE BRO CWA THROUGH 12Z MONDAY. ALSO THE LATES QPFERD DISC PLACES THE BEST POTENTIAL FOR EXCESSIVE RAINFALL THROUGH TOMORROW EVENING JUST NORTH OF THE BRO CWA. SINCE THE FFG FROM THE WGRFC FOR THE BRO CWA SHOWS THE 6 HOURLY FLASH FLOOD GUIDANCE GENERALLY FROM 4.5 TO 5.5 INCHES FOR THE CWA...BELIEVE THAT THE SOIL CONDITIONS WITHIN THE CWA CAN HANDLE THE CURRENTLY PROGGED QPF VALUES AT THIS TIME WITHOUT ANY SERIOUS FLOODING PROBLEMS. SO WILL NOT POST ANY FLOOD WATCHES FOR THE REGION AT THIS TIME. HOWEVER...THIS SITUATION WILL NEED TO BE CLOSELY MONITORED THROUGH THE EVENING AND OVERNIGHT HOURS IN CASE THE SYNOPTIC SITUATION CHANGES SIGNIFICANTLY. FOR TEMPERATURES... HAVE GONE WITH A BLEND OF THE MAV AND MET NUMBERS AS BELIEVE THAT THE WARMER MET GUIDANCE IS A LITTLE TOO WARM. FOR THE LONGER RANGE...BROAD 500 MB RIDGING PREVAILS FROM TUESDAY THROUGH THURSDAY WHICH WILL MAINTAIN AT OR ABOVE NORMAL TEMPS AND ZERO POPS. ANOTHER STRONG AND DEEPLY DIGGING 500 MB TROFFING WILL PUSH INTO THE CENTRAL AND EASTERN PORTIONS OF THE LOWER 48 STATES LATER THIS UPCOMING WEEK AND THIS FEATURE PULLS ANOTHER STRONG COLD FRONT THROUGH THE REGION NEXT FRIDAY. OVERALL MOISTURE VALUES AHEAD OF THIS FRONT ARE A LITTLE MORE LIMITED SO WILL GO WITH ONLY 20 TO 30 % FOR THE REGION AFTER FRIDAY. THANKS CRP FOR THE COORD! && .MARINE...TCOON OBS REPORT S WINDS AT 20 TO 30 MPH AND BUOY020 REPORTED SSE WINDS AT AROUND 20 KTS AND SEAS AT 9 FT. THE TIGHT PRESSURE GRADIENT OVER THE REGION WILL MAINTAIN ADVISORY CONDITIONS OVER THE LOWER TEXAS COASTAL WATERS TODAY. THE GRADIENT WILL RELAX OVERNIGHT AS A COLD FRONT MOVES INTO SOUTH TEXAS. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL PREVAIL SUNDAY AHEAD OF THE FRONT AS IT MIGRATES SOUTH INTO AND THROUGH THE REGION. MODERATE TO STRONG NORTH TO NORTHEAST WINDS IN THE WAKE OF THE FRONT WILL PRODUCE ADVISORY CONDITIONS INTO MONDAY. HIGH PRESSURE SHIFTS EAST BY TUESDAY WITH SOUTHEAST WINDS PREVAILING THROUGH THE FORECAST. && .AVIATION...VFR CONDITIONS WILL PREVAIL THIS AFTERNOON WITH GUSTY S WINDS PRODUCING LGT CHOP BLO 5KFT. ISOLD TO SCT CONVECTION WILL BEGIN MOVE FROM NW INTO THE CWA AFTER MIDNIGHT. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 81 86 73 86 71 / 30 60 40 30 0 BROWNSVILLE 80 87 71 86 69 / 30 60 40 30 0 HARLINGEN 78 87 71 86 68 / 30 60 40 30 0 MCALLEN 76 87 69 88 68 / 30 60 40 30 0 RIO GRANDE CITY 76 87 67 89 66 / 40 60 40 30 0 SOUTH PADRE ISLAND 81 86 77 86 72 / 30 60 40 30 0 && .BRO WATCHES/WARNINGS/ADVISORIES... SCA GMZ130-132-135 THROUGH 01Z. SCA GMZ150-155 THROUGH 05Z. SCA GMZ170-175 THROUGH SUNDAY MORNING.. && $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO SYNOPTIC/GRIDS....60 MARINE/AVIATION...55 MESO...VEGA tx