AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 817 PM EDT TUE OCT 23 2007 .UPDATE...THE COLD FRONT CONTINUES TO ADVANCE ACROSS THE CWA AS THE LATEST SFC ANALYSIS SHOWS ITS LEADING EDGE NEAR TALLAHASSEE EXTENDING NWD TO ALBANY AND FURTHER INTO NRN GA. WINDS HAVE BEEN SRLY AND GUSTY TO 25 MPH AHEAD OF THE FRONT...WHILE A WRLY WIND SHIFT IS VISIBLE BEHIND IT. MSAS OBS INDICATE A TIGHT DEW POINT GRADIENT JUST BEHIND THE FRONT AS DEW PTS ARE ALL THE WAY DOWN TO THE LOWER 50S IN SRN ALABAMA. H5 RUC ANALYSIS SHOWS THE DEEP CLOSED LOW CENTERED OVER SE ARKANSAS...WITH AN AMPLIFIED TROUGH EXTENDING SOUTHWARD INTO THE NWRN GULF OF MEXICO. THE DEEP TROUGH TRANSITIONS INTO RIDGING OVER THE WRN ATLANTIC. WV SAT IMAGERY SHOWS MUCH DRIER AIR AT THE MID- LEVELS...MOVING TO THE EAST FROM SRN TX INTO LA. AS THE DRIER AND COOLER AIR PROGRESSES ACROSS THE CWA THIS EVENING...A THIN LINE OF WEAK...LOW TOPPED SHOWERS CONTINUE TO PROPAGATE EWD ALONG THE FRONT. SHOWERS HAVE BEEN A BIT MORE ORGANIZED INTO SW GA...WITH THE LINE THINNING AND WEAKENING TOWARDS THE GULF COAST. BEHIND THE FRONT ISOLATED STRATIFORM PRECIP EXTENDS WELL INTO SRN ALABAMA. OVERNIGHT...THE COLD FRONT WILL CONTINUE TO PROGRESS EWD ACROSS THE CWA. LOW TEMP SPREAD WILL BE INTO THE LOWER 50S IN SE ALABAMA TO THE UPPER 60S OVER THE EASTERN FL BIG BEND. ISOLATED SHOWERS WILL LEAVE FOR A SLIGHT CHANCE OF RAIN ACROSS THE TRI-STATE AREA BEHIND THE FRONT FOR THE OVERNIGHT HOURS. && .AVIATION...A COLD FRONT WILL CONTINUE TO PUSH THROUGH THE EASTERN HALF OF THE FORECAST AREA OVER THE LATE EVENING HOURS. ISOLATED TO SCATTERED SHOWERS DEVELOPING NEAR AND ALONG THIS BOUNDARY WILL BE BRIEF AND COULD BRIEFLY DROP VSBYS. AFTER THE FRONTAL PASSAGE ...LIGHT WEST-NORTHWEST WINDS AND MVFR AND POSSIBLY DOWN TO IFR CIGS WILL PERSIST THROUGH MUCH OF THE TAF PERIOD. && .MARINE...COLD FRONT CROSSES THE FORECAST WATERS INTO EARLY WEDNESDAY MORNING. SOUTHERLY WINDS WILL CONTINUE TO RUN NEAR 20 KNOTS...AHEAD OF THE FRONT AND WITH INCREASING SEAS...A SMALL CRAFT ADVISORY WILL BE IN EFFECT FOR THE PANHANDLE OFFSHORE LEG UNTIL 00Z THURSDAY. AS THE FRONT PASSES WINDS WILL COME AROUND TO THE WEST AND NORTHWEST BEHIND THE BOUNDARY. THERE WILL BE A FEW SHOWERS AHEAD OF THE FRONT WITH SCATTERED LIGHT RAIN BEHIND IT. THE GRADIENT REMAINS SOMEWHAT TIGHT OVERNIGHT KEEPING WINDS AND SEAS UP. THROUGH THE REST OF THE WEEK...HIGH PRESSURE AND LIGHTER WINDS AND SEAS WILL SETTLE IN ACROSS THE NORTHEAST GULF FOR THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 63 67 51 73 55 / 40 40 20 20 20 PANAMA CITY 59 66 55 72 59 / 40 40 20 20 20 DOTHAN 55 64 51 69 52 / 40 40 40 30 20 ALBANY 62 67 53 70 53 / 40 40 40 20 20 VALDOSTA 65 70 54 75 57 / 50 40 30 20 20 CROSS CITY 69 75 58 78 60 / 50 50 20 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GMZ...SCA APALACHICOLA TO DESTIN 20-60NM OUT. && $$ CAMP/GIBBS/WOODRUM fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL3 400 PM EDT TUE OCT 23 2007 .SYNOPSIS... 19Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUE TO SHOW A VERY AMPLIFIED UPPER PATTERN ACROSS THE CONUS WITH DEEP TROUGHING OVER THE PLAINS/MISSISSIPPI VALLEY AND RIDGING ALONG BOTH THE ATLANTIC AND PACIFIC COASTS. LARGE CLOSED UPPER LOW IS SEEN SPINNING IN THE BASE OF THE TROUGH OVER THE ARKLATEX REGION SUPPORTING A LARGE AREA OF LOW STRATUS AND SCATTERED SHOWERS/SPRINKLES TO THE WEST OF OUR FORECAST AREA. OTHERWISE THE MAIN TROUGH AXIS IS PUSHING EAST WITH POTENT SHORTWAVE ENERGY MOVING THROUGH THE GREAT LAKES REGION. AT THE SURFACE...COLD FRONT PUSHING EAST INTO THE FORECAST AREA AT THIS TIME RUNNING FROM EASTERN AL INTO THE CENTRAL/EASTERN FLORIDA PANHANDLE AND ADJACENT COASTAL WATERS. THIN STRIP OF SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE FRONT IS NOT AS ORGANIZED AS DURING THIS PAST MORNING...BUT WILL CONTINUE TO MOVE SLOWLY EAST WITH THE FRONT AND GIVE MOST AREAS AT LEAST A CHANCE OF A BRIEF SHOWER OR STORMS INTO THE EARLY EVENING HOURS. A FEW ADDITIONAL SHOWERS HAVE BEEN TRYING TO FORM FURTHER EAST WITHIN THE DEEP SOUTHERLY FLOW...HOWEVER THESE HAVE REMAINED WIDELY SCATTERED IN NATURE. FAIRLY DRAMATIC DIFFERENCE IN AIRMASS ACROSS THE FRONT AT THIS TIME. TEMPS AHEAD OF THE FRONT ACROSS A LARGE PORTION OF THE FORECAST AREA ARE CURRENTLY IN THE 80S WITH DEWPOINTS IN THE 70S. BEHIND THE FRONT TEMPS ARE GENERALLY IN THE 60S TO MIDDLE 70S WITH DEWPOINTS FALLING BACK TO MORE COMFORTABLE 50S. && .SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)... UPPER AND DOMINANT LOW MOVES FROM THE ARKLATEX REGION THIS EVENING TO NORTHERN MISSISSIPPI TOWARD SUNRISE ON WEDNESDAY. SURFACE COLD FRONT MOVING EAST AHEAD OF THIS SYSTEM IS PROGGED TO REACH WESTERN GA/WESTERN FL BIG BEND THIS EVENING AND THEN PUSH TO EASTERN GA/NORTHEAST FLORIDA LATE TONIGHT. AS THE BEST DYNAMICS AHEAD OF THE FRONT DIMINISH OVERNIGHT...THE BAND OF SHOWERS AND ISOLATED STORMS ALONG THE FRONT WILL BECOME MORE BROKEN WITH TIME. RAINFALL AMOUNTS ARE NOT EXPECTED TO BE THAT HEAVY ACROSS THE EASTERN HALF OF THE FORECAST AREA AS A RESULT WITH A FEW LOCATIONS LIKELY MISSING THE RAIN ALL TOGETHER. WITH THIS IN MIND WILL KEEP A CHANCE OF SHOWERS/STORMS ACROSS THE EASTERN THIRD OF THE CWA OVERNIGHT WITH A SLIGHT CHANCE OF LIGHTER SHOWERS/SPRINKLES FURTHER WEST ASSOCIATED WITH THE DEEP LAYER Q-VECTOR CONVERGENCE AND COOL POOL DYNAMICS OF THE MID/UPPER LEVEL LOW. WILL SEE THE LOW STRATUS DECK AND COOLER TEMPS CURRENTLY OVER THE LOWER MISSISSIPPI VALLEY PUSH EAST THROUGH THE NIGHT. FOR WEDNESDAY WILL SEE THE COLD FRONT STALL TO THE EAST OF OUR AREA WITH THE BEST CONVECTIVE POTENTIAL ALSO TO OUR EAST. THE LATEST 12Z GFS SHOWS THE UPPER LOW DROPPING SOUTHEAST INTO SOUTHERN AL AND THE WESTERN FLORIDA PANHANDLE DURING THE DAY. THIS IS NOW THE CLOSEST APPROACH OF THE UPPER LOW THAT THE GLOBAL MODELS HAVE SHOWN. EVEN IF THE UPPER LOW DOESN`T MAKE IT QUITE THIS FAR SOUTH AND EAST (WHICH IT STILL MIGHT)...THE MID LEVEL COOL POOL AND DEEP LAYER Q-VECTOR CONVERGENCE SHOULD BE DEEPLY ENTRENCHED OVER THE AREA...ESPECIALLY TO THE WEST OF THE APALACHICOLA RIVER. THIS IS LIKELY TO RESULT IN ONE OF THE COOLEST DAYS SEEN IN A WHILE ACROSS THE WESTERN CWA WHERE HIGHS MAY STRUGGLE INTO THE LOWER AND MIDDLE 60S IN SPOTS UNDER STRATUS AND CONTINUES LIGHT SHOWERS/SPRINKLES. WILL NOT BE QUITE AS COOL ACROSS THE EASTERN HALF OF THE AREA WHERE THE BEST COLD AIR ADVECTION WILL NOT ARRIVE UNTIL LATE. STILL WILL SEE AT LEAST A SLIGHT CHANCE OF SHOWERS/SPRINKLES EVEN HERE...BUT THE STRATUS WILL NOT BE AS PREVALENT ALLOWING FOR MORE BREAKS OF SUN. WITH THE CONTINUED TREND SOUTH AND EAST WITH THE UPPER LOW WILL HAVE TO DROP TEMPS A BIT ACROSS THE EAST AS WELL. NOT GOING TO GO QUITE AS LOW AS THE MAV NUMBERS AT THIS TIME WHICH SHOW UPPER 60S TO NEAR 70 ALL THE WAY TO THE SUWANNEE RIVER VALLEY. CURRENT GRIDS ARE SHOWING UPPER 70S TO NEAR 80 IN OUR FAR EASTERN AREAS AND WILL BE TAKING ABOUT 5 DEGREES OF THESE NUMBERS AND ALLOW THE MIDNIGHT SHIFT TO TREND DOWN EVEN FURTHER IF NEEDED. UPPER LOW BEGINS TO SLOWLY PULL BACK NORTH LATE WEDNESDAY NIGHT OR THURSDAY. AS THIS OCCURS THE GFS IS SHOWING MID-LEVEL DRYING TRYING TO COME BACK INTO MUCH OF THE AREA WITH THE BEST Q-G FORCING PIVOTING TO THE NORTH OF THE AREA AS WELL. WITH THIS IN MIND SCATTERED LIGHT SHOWERS AND SPRINKLES SHOULD LARGELY COME TO AN END AS WELL. A COOL NIGHT IN STORE THOUGH WITH TEMPERATURES FALLING BACK THROUGH THE 50S REGIONWIDE. THURSDAY MORNING LOWS LOOK TO REACH LOWER AND MIDDLE 50S SOUTH AND EAST AND UPPER 40S TO LOWER 50S NORTH AND WEST. THURSDAY WILL BE A TRICKY DAY AS THE UPPER LOW CONTINUES TO LOSE INFLUENCE OF THE REGION. QUESTION IS JUST HOW MUCH CLOUD COVER WE SEE DURING THE DAY ALONG WITH THE EVENTUAL STRENGTH OF THE COOL POOL. GFS HAS HAD A LONG BIAS OF HOLDING ON TO THE STRENGTH OF COLD POOLS FOR A BIT TOO LONG. THE ECMWF MAY BE MORE REPRESENTATIVE AND IS RUNNING ON AVERAGE 2-3 DEGREES WARMER. EVEN THROUGH THE BEST DYNAMICS HAVE LIFTED NORTH FOR A MAJORITY OF THE DAY WOULD NOT BE SURPRISED TO SEE A FEW WIDELY SCATTERED LIGHT SHOWER OR SPRINKLES STILL HANGING AROUND THE AREA. THIS IS ESPECIALLY TRUE WITH THE DEGREE OF AFTERNOON STRATACU EXPECTED TO DEVELOP. A BIT BETTER MIXING DURING THE AFTERNOON THAN WILL BE SEEN ON WEDNESDAY WITH STILL SOME BREAKS OF SUN. ADDED A FEW DEGREES TO THE VERY COOL MAV NUMBERS TO ARRIVE AT AFTERNOON HIGH TEMPS. && .LONG TERM... (FRIDAY THROUGH TUESDAY) THE GFS AND ECMWF STALL THE FRONT JUST EAST OF OUR AREA THROUGH THE WEEKEND. THIS WILL KEEP OUR REGION NEAR A SHARP BAROCLINIC ZONE. LATEST INDICATION ARE THAT THIS BAROCLINIC ZONE MAY SET UP A BIT FURTHER EAST THAN EARLIER THOUGHT AND HAVE DROPPED POPS THURSDAY NIGHT THROUGH FRIDAY NIGHT GENERALLY INTO THE SLIGHT CHANCE RANGE (COORD WITH JAX/JAX/FFC/HPC). A SECONDARY PUSH IS FINALLY EXPECTED TO CLEAR THE FRONTAL BOUNDARY WELL EAST BY EARLY NEXT WEEK...RESULTING IN A SURGE OF COOLER DRIER AIR. && .MARINE... COLD FRONT CROSSES THE FORECAST WATERS TONIGHT INTO EARLY WEDNESDAY MORNING. SOUTHERLY WINDS WILL CONTINUE TO RUN IN THE CAUTIONARY LEVEL AHEAD OF THE FRONT FOLLOWED BY A PERIOD OF CAUTIONARY CONDITIONS ONCE WINDS COME AROUND TO THE WEST AND NORTHWEST BEHIND THE BOUNDARY. WILL BE A FEW SHOWERS AND PERHAPS A THUNDERSTORM AHEAD OF THE FRONT. GRADIENT REMAINS A BIT TIGHT OUT OF THE WEST AND NORTHWEST THROUGH THE DAY WEDNESDAY WITH CONDITIONS AT OR JUST BELOW CAUTIONARY LEVELS AT TIMES. WILL HAVE TO WATCH WAVE HEIGHTS ACROSS THE OFFSHORE WATERS AS WE MAY SEE THEM APPROACH ADVISORY LEVELS FOR A TIME ON WEDNESDAY. HIGH PRESSURE AND LIGHTER WINDS AND SEAS SHOULD THEN BUILD ACROSS THE NORTHEAST GULF FOR THE END OF THE WEEK. && .AVIATION... COLD FRONT CURRENTLY ENTERING THE WESTERN ZONES OF THE TAE FORECAST AREA...AND WILL MOVE THROUGH THE ENTIRE FORECAST AREA BY 03Z THIS EVENING. STRONG SOUTHERLY WINDS...GUSTING AS HIGH AS 30KTS...ARE OCCURRING IN ADVANCE OF THE FRONT. A NEARLY CONTINUOUS THIN NORTH-SOUTH LINE OF SHOWERS ARE OCCURRING ALONG THE FRONTAL BOUNDARY EXTENDING DOWN ACROSS EXTREME EASTERN ALABAMA THROUGH THE EASTERN FLORIDA PANHANDLE ON INTO THE SOUTH CENTRAL GULF OF MEXICO. SCATTERED SHOWERS ARE ALSO BEGINNING TO BREAK OUT IN THE WARM MOIST AIRMASS EAST OF THE FRONT. BEHIND THE FRONT...SOME LIGHT SHOWERS AND SPRINKLES WILL OCCUR WITH CIGS TO DROP TO IFR TO MVFR. EXPECT THESE CIGS TO OCCUR THROUGH MUCH OF THE FORECAST PERIOD. && .FIRE WX...NO CONCERNS. COOLER TEMPS...ABUNDANT CLOUDS AND CONTINUED SHOWER CHANCES WILL HELP KEEP CONDITIONS WELL BELOW CRITICAL LEVELS THROUGH THE MID WEEK PERIOD. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 63 67 51 73 55 / 40 40 20 20 20 PANAMA CITY 59 66 55 72 59 / 40 40 20 20 20 DOTHAN 55 64 51 69 52 / 40 40 40 30 20 ALBANY 62 67 53 70 53 / 40 40 40 20 20 VALDOSTA 65 70 54 75 57 / 50 40 30 20 20 CROSS CITY 69 75 58 78 60 / 50 50 20 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ AVIATION/FIRE WX...WATSON PUBLIC/MARINE...MROCZKA LONG TERM...FOURNIER/MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 1245 AM CDT TUE OCT 23 2007 .DISCUSSION... 304 PM CDT ANALYSIS INDICATES SURFACE COLD FRONT JUST CLEARING SOUTHEAST COUNTIES OF CWA AT 19Z...WHILE VAPOR IMAGERY/RUC INITIALIZATION INDICATES MID LEVEL LONG WAVE TROUGH SLOWLY APPROACHING MISSISSIPPI VALLEY FROM THE WEST. PRECIP HAS BEEN SLOW TO DEVELOP ACROSS THE FORECAST AREA TODAY...WITH BAND OF LIGHT SHOWERS MAINLY ASSOCIATED WITH FRONTOGENETIC FORCING ALONG IMPRESSIVE MID LEVEL THERMAL GRADIENT WEST OF THE CWA...WHILE SOMEWHAT MORE IMPRESSIVE RADAR RETURNS INDICATED FROM CENTRAL IL/IND INTO NORTHERN INDIANA CLOSER TO SURFACE FRONTAL ZONE AND MID LEVEL SHORT WAVE TROUGH LIFTING FROM LOWER OHIO VALLEY. LATEST RADAR MOSAICS DO INDICATE LIGHT SHOWERS ATTEMPTING TO FILL THE SPACES IN BETWEEN...ACROSS FORECAST AREA...THOUGH MODELS IN PRETTY GOOD AGREEMENT IN WEAKENING MAGNITUDE OF MID LEVEL THERMAL GRADIENT AND ASSOCIATED FRONTOGENETIC FORCING THROUGH THIS EVENING AS UPPER TROUGH CONTINUES TO MOVE EAST. THUS APPEARS TO BE A LOW QPF/RELATIVELY HIGH PROBABILITY OF SPRINKLES/LIGHT SHOWERS THIS EVENING ACROSS MUCH OF FORECAST AREA WHILE AREAS ALONG/EAST OF INDIANA BORDER TO SEE GREATER CHANCE OF MEASURABLE RAIN AS SHORT WAVE LIFTS NORTHEAST ACROSS THAT AREA THIS EVENING. MID LEVEL TROUGH THEN MOVING EAST OF FORECAST AREA BY MORNING...WITH WEAK SURFACE RIDGE AXIS BUILDING ACROSS SOUTHERN WI/EASTERN IA AND NORTHWEST IL AND CLEARING SKIES FROM THE NORTHWEST. WITH RIDGE MOVING INTO FAR NORTHWEST COUNTIES AROUND ROCKFORD BY SUNRISE...LOW 30S DEW POINTS AND POTENTIAL FOR BEST RADIATIONAL COOLING AND FROST DEVELOPMENT. WITH MID 30S EXPECTED IN COOLEST SPOTS THERE WILL BE ISSUING FROST ADVISORY FOR NORTH CENTRAL IL COUNTIES FOR EARLY TUESDAY MORNING. PRECIP THEN CLEARS SOUTHEAST COUNTIES BY MORNING...WITH SUBSIDENCE IN WAKE OF DEPARTING NORTHERN STREAM SHORT WAVE PULLING SURFACE RIDGE ACROSS FORECAST AREA AND CLEARING SKIES. GUIDANCE MAX TEMPS AROUND 60/LOW 60S WHICH APPEARS REASONABLE GIVEN LACK OF CLOUD COVER...WITH COOLER MAV GUIDANCE FAVORED TUESDAY NIGHT. NORTHWEST FLOW BRINGS ANOTHER WEAK DISTURBANCE LATE TUES/TUES NIGHT WHICH BRINGS REINFORCING SURFACE TROUGH/WEAK COLD FRONT THROUGH BY WEDNESDAY MORNING. MODEL TSECTS INDICATE LITTLE IN WAY OF MOISTURE WITH THIS...SO MAIN EFFECT JUST TO MAINTAIN COOL TEMPS DESPITE GOOD DEAL OF SUNSHINE ON WEDNESDAY. WITH AMPLIFIED UPPER RIDGE OVER WEST COAST...LOWER PORTION OF CURRENT LONG WAVE TROUGH CLOSING OFF OVER SOUTHERN PLAINS. MEDIUM RANGE GUIDANCE CONTINUES TO VARY SOMEWHAT WITH RESPECT TO EVENTUAL MINOR RETROGRESSION AND THEN OPENING/KICKING OUT WITH THIS SYSTEM...THOUGH 00/06/12Z RUNS OF GFS IN ENOUGH AGREEMENT TO OFFER A LITTLE MORE CONFIDENCE IN UPPER WAVE LIFTING OUT ACROSS NORTHERN IL/IN THURSDAY/FRIDAY WITH HIGHEST GUIDANCE POPS CLUSTERED ABOUT THE THURSDAY NIGHT/FRIDAY PERIOD. WHILE DETAILS WILL PROBABLY CHANGE WITH TIME...HAVE INTRODUCED CHANCE POPS FOR SHOWERS THURS NGT/FRI AS NORTHERN STREAM KICKER DIGS ACROSS NORTHERN PLAINS. SPOTTY PRECIP COULD POTENTIALLY LINGER THROUGH FRI NIGHT/EARLY SAT AS THIS NORTHERN STREAM KICKER PUSHES ACROSS NORTHERN LAKES...THOUGH BETTER CHANCE APPEARS TO REMAIN NORTH OF FORECAST AREA BY THEN. STRONG HIGH PRESSURE THEN BUILDS ACROSS THE MIDWEST IN ITS WAKE SATURDAY NIGHT/SUNDAY. RATZER && .AVIATION...DISCUSSION REGARDING 06Z TAFS... 1245 AM CDT CURRENT RADAR TRENDS SHOW LINGERING BANDS OF VERY LIGHT PCPN CONTG TO FORM OVR NERN MO/W CNTRL IL AND MOVE NEWD ACROSS IL/IN...GENLY E OF A BRL-VYS-UGN LN. CIGS GENLY VFR ALG/W OF THIS LN...WITH OCNL LOW RANGE MVFR CONDS TO THE E. THIS IS IN RESPONSE TO A WEAK DISTURBANCE IN THE MID LVLS. THIS IMPULSE SHOWS UP ON SATLT IMAGERY OVR E CNTRL MO...JUST NW OF STL...AND WILL CONTINUE TO ZIP NEWD AND DAMPEN OUT THRU 10Z. IN ITS WAKE...OCNL LGT RAIN WILL END LEAVING VFR CIGS ACRS ENTR TERMINAL AREA. LARGER MID LVL TROF FROM CNTRL ONTARIO TO LWR MO VLY IS SHIFTING SLOWLY EWD. AS THIS WAVE MOVES ACROSS UPR GRTLKS TDY...SKIES WILL CLR FROM W-E BY 16Z. SOME HI BASED DIURNAL CU LIKELY LATE MRNG-MID AFTN BUT NO CIG EXPECTED. NLY WINDS ARND 10 KT TO CONTINUE TIL ARND 17Z...THEN BACK INTO WSW BY 23Z AS SFC HI PRES RIDGE DROPS SEWD ACRS AREA THIS AFTN. WINDS TO DMNSH TO LGT SW THIS EVENING. MERZLOCK && .MARINE...PRELIMINARY DISCUSSION FOR 3AM ISSUANCE... 1250 AM CDT A WEAK LOW PRESURE AREA INCHES WAS LOCATED OVER QUEBEC WITH A FRONT TRAILING SOUTHWARD ACROSS THE LOWER GREAT LAKES. THIS LOW ASSOCIATED FRONT WILL CONTINUE EASTWARD TO NEW ENGLAND BY THIS EVENING. MEANWHILE...ANOTHER LOW PRESSURE SYSTEM OVER NORTHWEST MANITOBA WILL DROP QUICKLY SOUTHEASTWARD AND MOVE INTO THE UPPER GREAT LAKES BY THIS EVENING. ANOTHER COLD FRONT ASSOCIATED WITH THIS LOW WILL BRING AN INCRESE IN NORTHWEST WINDS TONIGHT INTO WEDNESDAY. AT THIS TIME...IT APPEARS WINDS BEHIND THIS NEXT COLD FRONT WILL REMAIN JUST BELOW GALE FORCE...BUT CONDITIONS WILL HAVE TO BE MONITORED CLOSELY TODAY. MERZLOCK && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FROST ADVISORY NORTH CENTRAL IL EARLY TUES. IN...NONE. LM...SMALL CRAFT ADVISORY THIS AFTERNOON THROUGH LATE TONIGHT WINTHROP HARBOR TO NORTHERLY ISLAND. SMALL CRAFT ADVISORY THIS AFTERNOON THROUGH EARLY TUESDAY MORNING NORTHERLY ISLAND TO MICHIGAN CITY. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 210 AM MDT TUE OCT 23 2007 .DISCUSSION...FORECAST CONCERNS ARE ON WINDS TODAY AND PRECIPITATION CHANCES FRIDAY NIGHT THROUGH EARLY SATURDAY. .SHORT TERM (TODAY-THURSDAY NIGHT)... FIRST ITEM TO ADDRESS IS THE FROST ADVISORY THAT IS IN EFFECT FOR NORTON...GRAHAM...SHERIDAN AND GOVE COUNTIES. AT PRESENT TIME TEMPERATURES ARE AROUND 38 IN NORTON...31 IN HILL CITY...36 IN HOXIE AND 30 IN GOVE. WILL CONTINUE THE ADVISORY AS TEMPERATURES MAY FALL ANOTHER FEW DEGREES. WARM FRONT CURRENTLY IN EASTERN COLORADO AND ALONG THE KS/NE LINE LOOKS TO REMAIN NEARLY STATIONARY THROUGH SUNRISE SO IT WONT HELP BRING TEMPS UP OVER THE EAST ANY TIME SOON. OTHERWISE...AN UPPER LEVEL LOW PRESSURE AREA CURRENTLY OVER NORTHEAST TEXAS WITH A TROUGH EXTENDING NORTHEASTWARD TOWARD ANOTHER UPPER LOW IN CANADA. MODELS ALL HAVE A FAIR HANDLING OF THIS FEATURE THROUGH 60 HOURS IN THAT IT WILL REMAIN SOUTHEAST OF THE AREA. IN THE 60-84 HOUR PERIOD (12Z THURSDAY TO 12Z FRIDAY) THERE IS SOME AGREEMENT THAT AN UPPER LEVEL HIGH WILL BUILD WEST OVER THE EAST COAST WITH A TROUGH SLOWLY PUSHING SOUTHEAST IN THE PACIFIC NORTHWEST. THIS WILL PUSH OUR UPPER LOW A BIT TOWARD THE NORTHWEST. GFS HAS THE LOW OVER ARKANSAS WHILE THE NAM HAS IT OVER CENTRAL OKLAHOMA. LOOKING AT THE PREVIOUS RUN OF THE MODELS SHOWS A BIT MORE CONSISTENCY IN THE NAM WITH THE PLACEMENT. THE 12Z ECMWF WAS IN BETWEEN THE TWO WHILE THE 00Z RUN IS NEARLY SPOT ON WITH THE GFS/UKMET. WILL WEIGHT THE LATTER PARTS OF THE FORECAST ON THE GFS/UKMET/CANADIAN AND ECMWF MODELS AS THE NAM SEEMS AN OUTLIER ALTHOUGH NOT BY FAR. ONLY IMPACT FROM THE NAM WOULD HAVE BEEN SLIGHTLY COOLER TEMPERATURES AND PERHAPS A FEW MORE CLOUDS. TEMPERATURES SHOW A NICE WARMUP TODAY WITH READINGS IN THE UPPER 60S TO LOW 70S. FOR WEDNESDAY 850/2M/MOS GUIDANCE TEMPS SHOW LITTLE CHANGE WITH MID/UPPER 60S WEST TO NEAR 70 ACROSS FAR EASTERN COLORADO AS JUST A TOUCH OF COOLER AIR WITH THE LOW STARTS TO IMPACT THE AREA. FOR THURSDAY WENT MID 60S EAST TO LOW 70S WEST. AGAIN...WITH THE LOW RETROGRADING TOWARD THE AREA COOLER AIR WILL IMPACT THE EAST THE MOST...LESS OVER THE WEST. NORTHWEST WINDS INCREASE TODAY INTO THE BREEZY TO WINDY CATEGORY AS 800 MB WINDS REACH THE 30 TO 40 KT RANGE. HAVE UPPED THE WINDS AS A RESULT WHICH ALSO MATCHES WELL WITH 03Z RUC WIND FORECASTS. AFTER TODAY WINDS WILL SHIFT TO THE NORTHEAST AND EAST AT RATHER LOW SPEEDS AS WE START TO FEEL THE IMPACTS OF THE UPPER LOW. HAVE TRENDED TOWARD THE GFS SOLUTION AND POPULATED THE GRIDS WITH ITS WINDS. .LONG TERM (FRIDAY-MONDAY)... FRIDAY...COLD FRONT MOVES THROUGH THE AREA DROPPING AFTERNOON TEMPERATURES BACK TOWARD 60 DEGREES. THE UPPER LOW CENTER IS NOW FORECAST TO BE WELL NORTHEAST OF THE AREA IN SOUTHERN MISSOURI PER GFS/ECWMF AND CANADIAN FORECASTS. POST FRONTAL LOW LEVEL MOISTURE MOVES INTO THE WESTERN 1/3 TO 1/2 OF THE AREA FRIDAY NIGHT. GFS/CANADIAN MODELS SHOWING SOME LIGHT QPF WITH THIS MOISTURE WITH GFS 850 TEMPERATURES FALLING INTO THE 0-2C RANGE. HAVE ADDED SOME SLIGHT CHANCE POPS FOR RAIN SHOWERS TIL 06Z THEN RAIN SHOWERS AND SNOW SHOWERS FROM 06Z-12Z. SATURDAY...AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTHEAST SATURDAY NIGHTS PRECIP SHOULD PUSH WESTWARD. MAY HAVE SOME POPS EARLY IN THE MORNING ACROSS THE WEST BUT FOR NOW HAVE KEPT IT DRY. TEMPERATURES FROM THE GFS/ECMWF IN GOOD AGREEMENT WITH READINGS AROUND 50 ACROSS THE WEST TO MID 50S EAST...A BIT LOWER THEN PREVIOUS FORECAST. SUNDAY...ONLY MINOR TWEAK TO HIGH TEMPERATURE FORECAST AS GFS/ECMWF 850 TEMPS SHOW HIGHS IN THE 60-63 RANGE. MONDAY...CURRENT FORECAST GOING IN THE RIGHT DIRECTION WITH WARMING THINGS UP FURTHER AS LATEST GFS SHOWING 850 TEMPS SUPPORTING READINGS AROUND 70 OR SLIGHTLY HIGHER. CURRENT GRIDS MAY NEED TO BE INCREASED A BIT BUT FOR NOW WILL NOT MAKE ANY CHANGES. LOOKS DRY AS WELL. && .AVIATION... WARM FRONT CURRENTLY SLIDING TO THE SOUTHEAST ACROSS EASTERN COLORADO WILL CONTINUE TO SLIDE ACROSS THE AREA TODAY. CURRENT LLWS NEAR GLD WILL END AS WINDS SHIFT AND INCREASE BEHIND THE FRONT. WIDESPREAD AREA OF CLOUDS WILL IMPACT KGLD AND EASTERN COLORADO IN THE MORNING...BUT CIGS WILL REMAIN VFR GENERALLY AROUND 7000FT. OTHER CONCERN FOR TODAY WILL BE WINDY CONDITIONS DEVELOPING IN THE LATE MORNING AND AFTERNOON. WINDS WILL BECOME NORTHWESTERLY AND INCREASE TO AROUND 25KTS WITH GUSTS APPROACHING 39KTS AT TIMES. WINDS WILL DIE DOWN AROUND SUNSET...WITH VFR CONDITIONS EXPECTED THROUGH TOMORROW NIGHT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...FROST ADVISORY UNTIL 9 AM CDT TUESDAY FOR KSZ004-015-016-029. NE...NONE. CO...NONE. && $$ DDT/DDT/JRM ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 145 AM CDT TUE OCT 23 2007 .DISCUSSION... DAYS 1-2... THE PRIMARY FORECAST CHALLENGE FOR THE NEST 48 HOURS WILL BE TEMPERATURES. LOOKING AT THE LATEST MODEL RUNS OF THE RUC...NAM...GFS AND HIRES ECMWF...THERE WILL BE LITTLE IN THE WAY OF WEATHER OVER DAYS ONE AND TWO. WITH THAT SAID...DO PLAN TO KEEP THE EXISTING FROST ADVISORY GOING THROUGH 14Z THIS MORNING...FOR ALL BUT COMANCHE AND BARBER COUNTIES. THE TEMPERATURES HAVE BEEN SLOWLY FALLING AS SKIES REMAIN CLEAR AND WIND TREND DOWNWARD TO LESS THAN 7KTS. ADDED AREAS OF FROST TO THE WX GRIDS...WHICH WERE AN OVERSIGHT OF THE PREVIOUS SHIFT. AS FOR MAX TEMPERATURES TODAY...SUNSHINE SHOULD COMBAT THE COOL NORTHERLY LOW LEVEL FLOW TO END UP WITH UPPER 60S FOR MOST LOCALS. THE WEST MAY APPROACH 70F...BUT STAYED JUST SHY OF THIS DUE TO THE SLOWER START TO WARMING UP. PER THE RUC GUIDANCE...NORTHWEST WINDS EARLY WILL SHIFT MORE NORTHERLY BY NOON AND RUN IN THE 18-21KT RANGE. THIS SHOULD THWART FULL SOLAR HEATING AND SLOW DOWN THE MID AFTERNOON WARM UP NORMALLY ENCOUNTERED THIS TIME OF YEAR. WINDS WILL BE SLACKING OFF AROUND SUNDOWN AND DECREASE TO NORTHWEST AT 5 TO 10 MPH OVERNIGHT. THINK THE WINDS AND A FEW HIGH CLOUDS WILL FILTER IN BY MIDNIGHT...SO MIN TEMPS SHOULD NOT BE AS COOL TUESDAY NIGHT. WILL HAVE TO WAIT AND SEE. SURROUNDING OFFICES SEEM TO AGREE..BUT STILL THINK A FEW LOCALS COULD EASILY DROP INTO THE 30S... ESPECIALLY IN THE NORTHERN COUNTIES. WEDNESDAY SHOULD BE MOSTLY SUNNY FOR THE MOST PART...NO MID OR LOWER CLOUDS SEEN ON THE HORIZON. THE WINDS WILL SHIFT MORE NORTHEAST TO EAST IN THE AFTERNOON...PREVENTING ANY GREAT WARM UP. WILL GO A COUPLE OF DEGREES WARMER WITH MY SOUTHWEST COUNTIES WARMING INTO THE LOWER 70S. MIN TEMPS WEDNESDAY NIGHT MAY DIP INTO THE UPPER 30S WEST TO AROUND 40 EAST. WINDS WILL SHIFT SOUTH OVER NIGHT...BUT DECOUPLE AND SPEEDS AVERAGE LESS THAN 8 KNOTS UNTIL AFTER SUNRISE THURSDAY. DAYS 3-7... NO SIGNIFICANT CHANGES BEING MADE TO THE EXT FCST THIS MORNING. GFS/ECMWF/CANADIAN MODELS ALL SHOW A SIMILAR PATTERN AT +120H (00Z SUN) WITH THE STUBBORN CUT-OFF LOW BECOMING ABSORBED IN THE POLAR WESTERLY FLOW AS IT REACHES THE OHIO VALLEY REGION. LARGE SURFACE ANTICYCLONE WILL GRIP THE CENTRAL CONUS WITH COOLER TEMPERATURES SATURDAY. TEMPERATURES WILL LIKELY NOT ESCAPE THE 50S OVER MUCH OF SOUTHWEST KANSAS WITH LOW LEVEL NORTH OR NORTHEASTERLY FLOW. THERE WILL BE A BRIEF WINDOW OF LOW CLOUDINESS FRIDAY AND/OR FRIDAY NIGHT JUST POLEWARD OF THE FRONT...HOWEVER IT APPEARS AS THOUGH THE UPCOMING WEEKEND WILL BE MARKED BY SEASONABLE TEMPERATURES AND ABSENCE OF ANY PRECIPITATION. && .AVIATION... AVIATION FCST LOOKS VERY TRANQUIL THROUGH 12Z WED. PREVAILING WIND DIRECTION IS EXPECTED TO BE FROM 330-360 DEGREES WITH SOME GUSTS IN THE 20-25 KT RANGE THIS AFTERNOON. NO VISIBILITY OR LOW CEILING CONCERNS EXPECTED THROUGH 12Z WED. && .PRELIMINARY POINT TEMPS/POPS... DDC 69 42 69 40 / 0 0 0 0 GCK 69 40 71 39 / 0 0 0 0 EHA 69 43 71 39 / 0 0 0 0 LBL 69 42 71 40 / 0 0 0 0 HYS 69 42 69 40 / 0 0 0 0 P28 68 43 67 43 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR KSZ030- 031-043>046-061>066-074>081-084>088. && $$ FN12/25/25 ks AREA FORECAST DISCUSSION...UPDATED FOR AVIATION NATIONAL WEATHER SERVICE MARQUETTE MI 725 PM EDT WED OCT 24 2007 .SHORT TERM (TONIGHT AND THU)... WATER VAPOR LOOP AND RUC ANALYSIS SHOW A CLOSED LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY...WITH A TROUGH AXIS STRETCHING NORTHEAST ACROSS THE LAKE HURON TO A LOW OVER WEST CENTRAL QUEBEC. A RIDGE IS PUSHING INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA. A SHORTWAVE MIGRATING THROUGH THE TROUGH IS OVER EASTERN U.P. ANOTHER TROUGH IS CRASHING INTO THE PACIFIC NORTHWEST. SURFACE ANALYSIS DEPICTS A LOW OVER GEORGIA...AND A BROAD RIDGE STRETCHING FROM THE CENTRAL PLAINS ACROSS THE FORECAST AREA INTO CENTRAL ONTARIO. TO THE WEST A FRONTAL SYSTEM EXTENDS FROM A LOW OVER NORTHERN SASKATCHEWAN ACROSS THE NORTHERN ROCKIES INTO CALIFORNIA. AN 850MB THERMAL TROUGH RUNS FROM JAMES BAY ACROSS THE FORECAST AREA PRODUCING A LAKE-850MB DELTA-T TO AROUND 10C. THE COMBINATION OF BOUNDARY LAYER MOISTURE AND DELTA-T`S IS JUST ENOUGH TO KEEP A FEW LAKE EFFECT SPRINKLES GOING ACROSS NORTH CENTRAL AND NORTHEAST U.P. AT THIS TIME. THE MID LEVEL TROUGH WILL MOVE INTO QUEBEC TONIGHT AS THE RIDGE PUSHES INTO NORTHWEST ONTARIO. ANOTHER SHORTWAVE EXTENDS FROM A LOW OVER CENTRAL CANADA SOUTHWEST INTO THE PACIFIC NORTHWEST. THE SURFACE HIGH WILL SPREAD ACROSS THE FORECAST AREA TONIGHT. TO THE WEST...A COLD FRONT DRAPES FROM NORTHERN MANITOBA SOUTHWEST INTO NORTHERN MONTANA. DRY AIR WILL ADVECT INTO THE AREA AND THE WINDS WILL BACK SOUTH AS THE HIGH MOVES THROUGH WHICH WILL KILL OFF ANY CHANCE OF LAKE EFFECT RAINS AND CAUSE SOME SKIES TO CLEAR. THE DRIER AIR...LIGHT WINDS DUE TO THE HIGH...AND CLEARING SKIES WILL ENCOURAGE SIGNIFICANT RADIATIONAL COOLING. THUS WILL KEEP TEMPERATURES A LITTLE BELOW GUIDANCE. THE RIDGE WILL REMAIN OVER THE FORECAST AREA PRODUCING A MOSTLY SUNNY SKIES. WARM AIR ADVECTION WITH SOUTHERLY WINDS WILL PUSH TEMPERATURES UP INTO THE 50S. .LONG TERM (THU NIGHT THRU WED)... SFC RIDGE AXIS WILL LINGER OVER THE AREA THU NIGHT...AND WITH MIN PRECIPITABLE WATER AXIS OF 1/4 TO 1/3RD OF AN INCH OVER THE AREA FOR A PORTION OF THE NIGHT...RADIATIONAL COOLING WILL BE ENHANCED. WHILE THERE MAY BE SOME INCREASE IN CLOUDS FROM THE S LATE...STILL EXPECT SUFFICIENT RADIATIONAL COOLING TO GO AT OR BLO THE COOLER GFS MOS GUIDANCE IN MANY AREAS. UPPER 20S/LWR 30S SHOULD BE COMMON IN THE INTERIOR. FRI INTO SAT...FCST REVOLVES AROUND EVOLUTION OF MID/UPPER LEVEL LOW OVER THE LWR MISSISSIPPI VALLEY AS IT IS PICKED UP BY SHORTWAVE TRACKING ALONG THE U.S./CANADIAN BORDER. MODEL CONSENSUS IS THAT THE LOW SHOULD DRIFT TO THE LWR OHIO VALLEY BY FRI EVENING AND THEN UP THE OHIO VALLEY EARLY SAT IN RESPONSE TO SHORTWAVE THAT WILL TRACK E TO THE UPPER LAKES BY SAT AFTN. WITH TRACK OF MIDLEVEL LOW WELL S OF HERE...THE GFS MIGHT BE TOO AGGRESSIVE BRINGING LIGHT PCPN INTO THE E HALF OF THE FCST AREA FRI...ESPECIALLY CONSIDERING THERE IS NO ISENTROPIC ASCENT. WHILE THERE IS FAIRLY SIGNIFICANT MOISTENTING OF THE COLUMN...OVERALL FORCING IS VERY WEAK. PREVIOUS SHIFT WAS CONSIDERING TRIMMING BACK POPS...AND THERE APPEARS TO BE ENOUGH EVIDENCE TO GO IN THAT DIRECTION NOW. WILL MAINTAIN 30 POPS OVER THE FAR SE WITH A BUFFER OF 20 POPS...BUT REMOVE PCPN FOR THE W HALF OF THE FCST AREA FRI. WILL CARRY THAT THEME INTO FRI EVENING AS WE AWAIT APPROACHING SHORTWAVE FROM THE WNW. THAT SHORTWAVE WILL PASS SAT. DECENT 500MB HEIGHT FALLS UPWARDS OF 100M IN 12HR OVER THE NRN FCST AREA SUGGEST PCPN MENTION IS NEEDED. SINCE DEEP LAYER FORCING IS RATHER WEAK...WILL KEEP POPS IN THE THE CHC CATEGORY BEGINNING OVERNIGHT FRI. FAIRLY STRONG CAA ASSOCIATED WITH SHORTWAVE WILL SEND 850MB TEMPS DOWN TO -6 TO -8C BY SAT EVENING. SO...NW FLOW LAKE EFFECT PCPN WILL LIKELY DEVELOP FROM W TO E AS THE DAY PROGRESSES. 1000-850MB THICKNESS FALLING BLO 1300M SUGGESTS -SHRA MIXING WITH/CHANGING TO -SHSN OVER THE W AND NCNTRL DURING THE AFTN AS BOUNDARY LAYER TEMPS FALL THRU THE DAY. FCST SOUNDINGS SUPPORT THIS CHANGEOVER. LAKE EFFECT REGIME WILL CONTINUE SAT NIGHT INTO SUN MORNING...BUT WITH GFS FCST SOUNDINGS SHOWING AN INVERTED-V LOOK AT THE LOWEST LEVELS...PCPN WILL BE LIGHT AND SCT. SUN THRU WED...ECMWF/CANADIAN/UKMET/GFS ARE ACTUALLY IN QUITE GOOD AGREEMENT DURING THIS PERIOD. THERE ARE SOME DIFFERENCES IN THE AMPLITUDE OF THE FLOW (MAINLY THE CANADIAN WHICH IS MUCH MORE AMPLIFIED THAN THE OTHER MODELS)...BUT OVERALL PATTERN AND TIMING OF SHORTWAVES IS GOOD FOR THE 4-7DAY PERIOD. TWO SHORTWAVES WILL AFFECT THE WEATHER HERE DURING THIS TIME FRAME...THE FIRST MON AND THE SECOND WED. ALTHOUGH THERE IS NO OPPORTUNITY FOR MOISTURE RETURN WITH THE FIRST SHORTWAVE APPROACHING FROM THE WNW...LOW END CHC POPS ARE WARRANTED MON WITH THE BEST CHC OF SEEING PCPN OVER THE N AND E WHERE THERE IS A BETTER COMBINATION OF WAA/ISENTROPIC ASCENT AND HEIGHT FALLS. GFS OPERATIONAL RUNS ARE COLD ENOUGH FOR LAKE EFFECT PCPN BEHIND SYSTEM AS THEY SHOW 850MB TEMPS DROPPING TO -8C. ECWMF SHOWS A MORE MODERATE -3C. GFS ENSEMBLE MEAN IS AROUND -5C WHICH WOULD BE JUST SUFFICIENT FOR THE POSSIBILITY OF LAKE EFECT -SHRA/-SHSN IN THE NW FLOW BEHIND SHORTWAVE. WILL CARRY POPS MON NIGHT INTO TUE MORNING...BUT NOTHING MORE THAN 30-40PCT GIVEN MARGINAL OVERWATER INSTABILITY AND OVERALL DRY AIRMASS INDICATED. WITH THE NEXT SHORTWAVE ARRIVING WED...ONCE AGAIN...MOISTURE RETURN WILL BE LIMITED. NONETHELESS...AS WITH THE SHORTWAVE MON...LOW END CHC POPS ARE REASONABLE. TEMPS THRU THE PERIOD SHOULD BE CLOSE TO NORMAL ON THE WHOLE....BUT COULD FLUCTUATE QUITE A BIT DAY TO DAY DEPENDING ON AMPLITUDE OF THE 2 SHORTWAVES PASSING THRU THE AREA. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... EXPECT ANY LINGERING SC TO DISSOLVE THIS EVNG AT BOTH SITES AS HI PRES RDG/DRIER AIRMASS/LOWER INVRN BASE OVER WRN LK SUP/NE MN CONTS TO THE E. VFR CONDITIONS WL THEN PREDOMINATE WITH RDG IN CONTROL THRU THU. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... THIS EVENING PRESSURE GRADIENT FALLS APART AS HIGH BUILDS FIRMLY INTO THE REGION. WINDS WILL SUBSIDE QUICKLY AND REMAIN BELOW 20 KNOTS INTO LATE FRIDAY. ANOTHER BOUT OF STRONG TO POTENTIALLY GALE FORCE NORTHERLY WINDS WILL ARRIVE LATE FRIDAY NIGHT INTO SATURDAY AS PRESSURE GRADIENT TIGHTENS BETWEEN PLAINS HIGH AND DEEPENING LOW OVER LOWER GREAT LAKES. WINDS WILL DIMINISH LATER SATURDAY NIGHT INTO SUNDAY AS A HIGH PRESSURE RIDGE SETTLES OVER THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...DLG LONG TERM...ROLFSON AVIATION...KC MARINE...DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 138 PM EDT WED OCT 24 2007 .AVIATION...AFTER SOME LINGERING LAKE EFFECT SHOWERS AND MVFR CIGS EARLY THIS EVENING...HIGH PRESSURE BUILDING INTO THE AREA WILL QUICKLY DRY THINGS OUT AND CLEAR THE SKIES. IN ADDITION...GUSTY NORTH TO NORTHWEST WINDS THIS AFTERNOON WILL ALSO DIMINISH EARLY THIS EVENING...BECOMING LIGHT AND VARIABLE FOR THE OVERNIGHT. AS THE HIGH PUSHES EAST OF THE REGION TOMORROW...EXPECT A LIGHT SOUTHEAST FLOW TO DEVELOP. DESPITE DEPARTING HIGH PRESSURE...EXPECT CLEAR SKIED TO CONTINUE THROUGH THURSDAY. MSB && .UPDATE...ISSUED 959 AM A DAY MORE TYPICAL FOR LATE OCTOBER ACROSS THE NORTHLAND... WINDY...COOL...AND RATHER DAMP. NORTHWEST FLOW CAA CONTINUES BEHIND DEPARTING SHORTWAVE...WITH LATEST RUC ANALYSIS SHOWING 850MB TEMPERATURES RANGING FROM -6C OVER CENTRAL LAKE SUPERIOR TO -3C OVER NORTHERN LAKE MICHIGAN. THIS...COMBINED WITH LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN WATER TEMPERATURES RUNNING AT 14C AND 10C RESPECTIVELY (PER NORTHERN LAKE MICHIGAN BUOY AND GREAT LAKES SURFACE ENVIRONMENTAL ANALYSIS)...LAKE INDUCED EQUILIBRIUM LEVELS ON THE ORDER OF 6.5KFT...AND 900MB TO 700MB RH PERCENTAGES >70 PERCENT...MORE THAN SUFFICIENT TO KICK OFF LAKE EFFECT RAIN SHOWERS OVER TYPICAL NORTHWEST TO NORTH NORTHWEST FLOW AREAS. SHOWERS EVEN APPEAR TO BE GETTING A LITTLE BOOST FROM SUBTLE LAKE INDUCED SURFACE TROUGH HANGING BACK WEST JUST SOUTH OF THE STRAITS REGION. FORTUNATELY (OR UNFORTUNATELY...DEPENDING ON YOUR POINT OF VIEW) TEMPERATURES IN THE LOW TO MID 40S MAKING SURE ALL PRECIPITATION STAYS IN THE LIQUID VARIETY. FORECAST CONCERNS FOR THE REMAINDER OF THE DAY CENTER ON GRADUALLY DEMISE OF LAKE SHOWERS AND WHAT TO DO WITH CURRENT MARINE HEADLINES UNDER GUSTY MORNING WIND REGIME. ONGOING LAKE EFFECT SHOWERS SHOULD SLOWLY DECREASE IN COVERAGE AND INTENSITY AS UPSTREAM ACARS SOUNDINGS CONFIRM LATEST MODEL GUIDANCE THAT BEST MID LEVEL MOISTURE WILL GRADUALLY PEEL OFF THROUGH THE REMAINDER OF THE MORNING AND AFTERNOON AND INVERSION HEIGHTS WILL CONTINUE TO LOWER. HOWEVER...DESPITE LOSS OF SHOWER ACTIVITY BY LATER THIS AFTERNOON...DELTA T/S REMAINING IN THE UPPER TEENS SHOULD KEEP THE LAKE STRATO CU GENERATION GOING...LEADING TO MOSTLY CLOUDY SKIES OVER FAVORED NNW FLOW AREAS OF NORTHERN LOWER AND PARTLY CLOUDY SKIES ELSEWHERE. LIMITED POTENTIAL FOR SUN (ESPECIALLY ACROSS NORTHWEST LOWER) AND CONTINUING CAA SHOULD KEEP HIGHS IN THE 40S TO LOWER 50S (WARMEST NEAR THE LAKE SHORES AND FAR SOUTHEAST AREAS). MARINE...AFTER GALE CONDITIONS ACROSS LAKE MICHIGAN AND NEAR GALES OVER WHITEFISH BAY THIS MORNING...GRADUALLY WEAKENING PRESSURE GRADIENT AND LOWERING INVERSION HEIGHTS SHOULD KEEP ANY WIND GUSTS BELOW GALE CRITERIA FOR THE REMAINDER OF THE DAY. HOWEVER...WITH BUFKIT ANALYSIS SHOWING GUST POTENTIAL OF AT LEAST 25 KNOTS AND THE STILL CHOPPY CONDITIONS OVER LAKE MICHIGAN (NORTHERN BUOY WAVES RUNNING AT 6FT)...WILL REPLACE ALL GALES WITH SCA/S. ELSEWHERE... WILL MAINTAIN CURRENT ADVISORIES. UPDATED GRIDS/NEARSHORES/ZONES OUT SHORTLY. MSB && .PREV DISCUSSION... /ISSUED 411 AM EDT WED OCT 24 2007/ DISCUSSION...CLIPPER TYPE SYSTEM CURRENTLY ADVANCING THROUGH THE REGION THIS MORNING...WITH SURFACE COLD FRONT COMING ONSHORE FROM LAKE MICHIGAN AS OF 06Z. IN THE WAKE OF THIS SYSTEM...PLENTY COLD AIR (H85 TEMPS DROPPING TO -4C TO -6C PER UPSTREAM RAOBS) LIGHTING UP THE LAKE EFFECT MACHINE OVER LAKE SUPERIOR...LIKELY SOON TO OCCUR OFF LAKE MICHIGAN AS WELL. THE PRIMARY FORECAST CHALLENGE THROUGH THE SHORT TERM IS ADDITIONAL PRECIPITATION CHANCES TODAY AS WELL AS TEMPERATURES/WINDS. INITIAL SHOT OF PRECIP WILL BE HEADED OUT OF THE PICTURE PRIOR TO 12Z AS BEST DEEP LAYER (700-300MB) QG SUPPORT SLIPS EAST WITH THE PASSAGE OF THE UPPER TROUGH. HOWEVER...UPSTREAM RADARS INDICATIVE OF WHAT`S IN STORE THROUGH THE DAY AS THERMAL TROUGH DROPS OVER THE NORTHERN GREAT LAKES. 850MB TEMPS IN THE -4C TO -6C RANGE OBVIOUSLY MORE THAN SUFFICIENT FOR SIGNIFICANT OVERLAKE INSTABILITY (SFC-850MB DELTA T/S IN EXCESS OF 16C)...WITH TRAJECTORIES SLOWLY TRANSLATING FROM NORTHWEST EARLY THIS MORNING TO NORTH/NORTHWEST AROUND 15Z...AND THEN EVENTUALLY MORE NORTHERLY BY LATE AFTERNOON AS LOW LEVEL RIDGING QUICKLY ADVANCES TOWARD THE WESTERN U.P. IN TYPICAL LAKE EFFECT FASHION...MID/UPPER MOISTURE WILL BE ON THE WANE EARLY THIS MORNING...HOWEVER LOW LEVEL MOISTURE EXCELLENT AS 925-800MB RH HOLDS AROUND 90% THROUGH 18Z...WITH INVERSION HEIGHTS UP AROUND 6500 FEET. THUS...ANTICIPATE A CONTINUED UPTICK IN LAKE EFFECT SHOWERS THROUGH MID TO LATE MORNING AS COLDEST OF THE AIR DROPS OVERHEAD... BEFORE A RATHER ABRUPT END TO ACTIVITY BY MID TO LATE AFTERNOON AS FLOW QUICKLY BECOMES ANTICYCLONIC AND INVERSION HEIGHTS CRASH/ MOISTURE SHALLOWS WITH APPROACH OF LOW LEVEL RIDGE. HIGHS TODAY RATHER IFFY PENDING PLACEMENT OF CLOUD COVER/PRECIP...BUT WITH ONGOING COLD ADVECTION THROUGH EARLY AFTERNOON FORESEE MANY LOCATIONS AWAY FROM THE IMMEDIATE LAKE SHORES STRUGGLING THROUGH THE 40S. TONIGHT INTO THURSDAY A MUCH DIFFERENT STORY WITH INCREASINGLY DEEP LAYER RIDGING TAKING HOLD AS HEIGHTS REBOUND TO THE NORTH OF CLOSED VORTEX MEANDERING OVER THE SOUTH. WITH INCREASING SUBSIDENCE/DEEP DRYING (900-300MB RH FALLS THROUGH THE FLOOR AT 15% OR LESS)...A PERIOD OF CLEAR SKIES CERTAINLY LOOKS IN THE WORKS. GIVEN PLACEMENT OF LOW LEVEL RIDGE AXIS OVER THE CWA TONIGHT...APPEARS TEMPERATURES WILL BE QUITE COLD - PERHAPS THE COLDEST YET THIS SEASON - WITH READINGS WELL INTO THE 20S FOR THE NORMALLY COLDER VALLEYS GIVEN ALREADY COOL START EXPECTED BY EARLY EVENING. PLENTY OF SUNSHINE ON THURSDAY WITH INCREASING WARM ADVECTION INTO THE AFTERNOON SHOULD LEAD TO QUITE THE SEASONABLE DAY...WITH HIGHS WELL INTO THE 50S IF NOT NEAR 60 IN A FEW SPOTS. MARINE ISSUES...AS ANTICIPATED...SEEING A QUICK UPTICK IN WINDS OVER THE LAKES AS COLD ADVECTION ENSUES AND CORE OF STRONGEST 900-800MB WINDS ADVANCES THROUGH INCREASINGLY MIXED LAYER. PER UPSTREAM VAD WIND PLOTS AND 06Z RUC ANALYSIS...APPEARS STRONGEST CORE OF WINDS WILL SLIDE THROUGH THE REGION BETWEEN NOW AND 15Z...DIMINISHING RATHER QUICKLY THEREAFTER. SOME QUESTION ABOUT ACHIEVABILITY OF GALES THIS MORNING FOR WHITEFISH BAY/LAKE MICHIGAN...NAMELY GIVEN ROUGHLY 35 KNOTS (MAYBE BRIEFLY HIGHER) THROUGH THE MIXED LAYER AS BEST CORE WINDS SLIDES BY TO THE WEST...HOWEVER MID LAKE BUOY IN NORTHERN MICHIGAN ALREADY PEAKING AROUND 33 KNOTS...SO WILL OBVIOUSLY LEAVE GOING MENTION IN PLACE AS THINGS SHOULD TREND UP JUST A BIT THROUGH 12Z. ELSEWHERE...SMALL CRAFT CONDITIONS A NEAR CERTAINTY THROUGH LATE AFTERNOON (INCLUDING LOCATIONS WHERE CURRENT GALES ALREADY UP)...WITH WINDS ALL LOCATIONS DIMINISHING RATHER QUICKLY THIS EVENING AS HIGH PRESSURE TAKES OVER. LATER PERIODS (THURSDAY NIGHT THROUGH SUNDAY)...MODEL GUIDANCE CONTINUES TO ATTEMPT TO LOCK ONTO A SOLUTION REGARDING THE SOUTHERN CLOSED LOW...WHICH WILL HAVE A BIG IMPACT ON THE LATE WEEK/WEEKEND WEATHER OVER NORTHERN MICHIGAN. 00Z GFS/GFS ENSEMBLE MEAN/CANADIAN AND 12Z ECMWF REMAIN IN QUITE GOOD AGREEMENT DEPICTING A GRADUAL SHIFT OF THE CYCLONE TOWARD THE LOWER GREAT LAKES BY SATURDAY AS ADDITIONAL NORTHERN STREAM ENERGY PROGRESSING THROUGH THE ROCKIES YIELDS A WEAKNESS IN THE MID LEVEL FLOW SUFFICIENT TO "CATCH" THE SYSTEM. SHOULD THIS SCENARIO OCCUR...INCREASINGLY DIVERGENT MID LEVEL FLOW COUPLED WITH AMPLE ATLANTIC MOISTURE AND INCREASING ISENTROPIC UPGLIDE AS TONGUE OF WARM ADVECTION WRAPS NORTH AHEAD OF THE GYRE WOULD CERTAINLY BE SUFFICIENT TO PRODUCE PRECIPITATION. CURRENT FORECAST ALREADY SUPPORTS CHANCES FOR RAIN FRIDAY THROUGH SUNDAY TIMEFRAME AND THIS LOOKS GOOD GIVEN REMAINING UNCERTAINTIES. LAWRENCE && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1723 AM EDT WED OCT 24 2007 UPDATED AVIATION SECTION FOR 18Z TAFS .DISCUSSION (1030 AM EDT)... MAIN FORECAST CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR PRECIPITATION THIS AFTERNOON. WATER VAPOR LOOP AND RUC ANALYSIS SHOWS THAT THE MID AND UPPER LEVEL TROUGH AXIS HAS MOVED EAST OF THE FORECAST AREA. HIGH PRESSURE OVER THE NORTHERN PLAINS CONTINUES TO EDGE INTO THE UPPER MISSISSIPPI RIVER VALLEY. PRESSURE GRADIENTS BETWEEN THE TROUGH TO THE EAST AND THE HIGH ARE WEAKENING AS THE RIDGE APPROACHES THE U.P. COLD AIR ADVECTION ASSOICATED INSTABILITY ALSO GENERATING LAKE EFFECT RAIN SHOWERS WITH BEST COVERAGE AT THIS TIME OVER CENTRAL AND EASTERN LAKE SUPERIOR. THIS AFTERNOON...SCATTERED SHOWERS OVER THE EASTERN U.P. WILL DIMINISH AS RIDGING STARTS TO BUILD IN FROM WEST AND FLOW BECOMES INCREASINGLY ANTICYCLONIC. SHOWERS SHOULD END THIS AFTERNOON FOR ALL BUT THREE EASTERN COUNTIES WHERE LONGER FETCH OVER THE LAKE COULD STILL SUSTAIN SOME SCATTERED SHOWER ACTIVITY. MODEL SNDGS ALSO SHOW INVERSION HEIGHTS LOWERING TO 4KFT OR LESS WITH INCREASINGLY DRIER AIR BELOW THE INVERSION BY EARLY AFTERNOON. THIS SHOULD CAUSE CLOUDS TO BREAK UP OVER WEST AND CENTRAL COUNTIES WITH INCREASING SUBSIDENCE WHICH IS ALREADY STARTING TO HAPPEN. PLAN TO UPDATE THE FORECAST MAINLY TO UPDATE THE WORDING. .EXTENDED... TONIGHT...GOOD RADIATIONAL COOLING EXPECTED WITH SFC RDG MOVING OVER AREA. LOOK FOR TEMPS TO DIP INTO THE LOW TO MID 20S FOR FAVORED INLAND COLD SPOTS. BOUNDARY LYR WINDS INCREASING TO 15-20 KT OVER THE FAR WEST OVERNIGHT COULD TEMPER COOLING SOMEWHAT BY DAYBREAK. THU...WITH THE SFC AND MID LEVEL RDG STILL OVER THE REGION WOULD EXPECT MOSTLY SUNNY SKIES. SUNSHINE AND MIXING TO 900 MB TEMPS AROUND 5C SHOULD PUSH MAX TEMPERATURES INTO THE MID TO UPPER 50S...PER GFS MOS GUIDANCE OR SLIGHTLY HIGHER. THU NIGHT...SFC RIDGE AXIS HOLD FIRM OVER THE AREA SO AGAIN EXPECT FAVORABLE RADIATIONAL COOLING ESPECIALLY OVER THE WRN INTERIOR WHERE READINGS SHOULD LOWER TOWARD GFS MOS GUIDANCE (AROUND 30F). BACKED OFF ON INCREASING CLOUDS SOME AS MODELS TRENDING SLOWER WITH ADVANCE OF SYSTEM OVER THE LOWER MISS VALLEY. FRI INTO SAT...FOLLOWING THE NCEP PREFERRED 12Z ECMWF SOLN WHICH HAS THE SUPPORT OF MODEL ENSEMBLES...BACKED OFF SOME ON TIMING OF INCREASING CLOUDS FOR FRI AS ECMWF IS SOMEWHAT SLOWER NOW THAN 00Z GFS WITH ADVANCE OF LOWER MISS VALLEY SYSTEM. STILL KEPT IN CHC OF RAIN FOR COUNTIES ALONG LAKE MI WITH SLIGHT CHC ELSEWHERE BY FRI AFTERNOON. ALSO CONTINUED GOING FCST OF CHC OF RAIN FRI NIGHT ACROSS THE CWA...BUT COULD EASILY SEE POPS BEING TRIMMED BACK IF ECMWF CONTINUES EASTWARD TREND WITH SYSTEM THROUGH THE OHIO VALLEY AND ERN GREAT LAKES. ALSO CHCS FOR LAKE EFFECT PCPN FOR SAT COULD BE DIMINISHED AS WELL WITH ECMWF TRENDING TOWARD MORE ANTICYCLONIC NRLY FLOW OVER THE AREA WITH GREATER INFLUENCE OF NRN PLAINS RIDGE. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... MVFR CEILINGS WILL CONTINUE INTO EARLY AFTERNOON WITH WEAK LAKE EFFECT SHOWERS IN PLACE. ENOUGH COOL AIR IS ALLOWING SNOW TO MIX WITH RAIN AT KCMX. ALTHOUGH SHOWERS REMAIN ISOLATED WITH DRY AIR JUST ABOVE CLOUD BASE...EXPECT A FEW PERIODS EARLY THIS AFTERNOON OF MVFR CEILIGNS IN LIGHT SHOWERS. ENOUGH MIXING WILL OCCUR TO LIFT CEILINGS TO VFR THIS AFTERNOON AND SKIES SHOULD COMPLETELY CLEAR THIS EVENING. THE LOWER LEVELS WILL REMAIN TOO DRY FOR ANY FOG FORMATION TONIGHT. A WEAK LOW LEVEL JET WILL SHIFT INTO WESTERN LAKE SUPERIOR INCREASING THE MIXING LAYER WINDS TO 20 KNOTS...SO EXPECT SOME GUSTY CONDITIONS TO KCMX ON THURSDAY MORNING AT KCMX. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... GALES TO 45 KNOTS DEVELOPED IN WAKE OF COLD FRONT LATE LAST EVENING. GALES EXPECTED EARLY TODAY WITH TIGHT PRESSURE GRADIENT LINGERING BETWEEN PLAINS HIGH AND DEPARTING LOW PRESSURE SYSTEM OVER ONTARIO. PRESSURE RISE OF 6 MB/3 HR WILL ALSO SWING ACROSS THE LAKE TO HELP KEEP GALES GOING. BY THIS EVENING PRESSURE GRADIENT FALLS APART AS HIGH BUILDS FIRMLY INTO THE REGION. WINDS WILL SUBSIDE QUICKLY AND REMAIN BELOW 25 KNOTS INTO LATE FRIDAY. EXPECT ANOTHER BOUT OF STRONG TO POTENTIALLY GALE FORCE NORTHERLY WINDS LATER FRIDAY NIGHT INTO SATURDAY AS PRESSURE GRADIENT TIGHTENS BTWN PLAINS HIGH AND DEEPENING LOW OVER LOWER GREAT LAKES. WINDS DIMINISH LATER SAT NIGHT INTO SUNDAY AS HIGH PRESSURE RIDGE SETTLES OVER THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...DLG EXTENDED...VOSS AVIATION...DLG MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1025 AM EDT WED OCT 24 2007 UPDATED AVIATION SECTION FOR 12Z TAFS .DISCUSSION (530 AM EDT)... MAIN FORECAST CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR PRECIPITATION THIS AFTERNOON. WATER VAPOR LOOP AND RUC ANALYSIS SHOWS THAT THE MID AND UPPER LEVEL TROUGH AXIS HAS MOVED EAST OF THE FORECAST AREA. HIGH PRESSURE OVER THE NORTHERN PLAINS CONTINUES TO EDGE INTO THE UPPER MISSISSIPPI RIVER VALLEY. PRESSURE GRADIENTS BETWEEN THE TROUGH TO THE EAST AND THE HIGH ARE WEAKENING AS THE RIDGE APPROACHES THE U.P. COLD AIR ADVECTION ASSOICATED INSTABILITY ALSO GENERATING LAKE EFFECT RAIN SHOWERS WITH BEST COVERAGE AT THIS TIME OVER CENTRAL AND EASTERN LAKE SUPERIOR. THIS AFTERNOON...SCATTERED SHOWERS OVER THE EASTERN U.P. WILL DIMINISH AS RIDGING STARTS TO BUILD IN FROM WEST AND FLOW BECOMES INCREASINGLY ANTICYCLONIC. SHOWERS SHOULD END THIS AFTERNOON FOR ALL BUT THREE EASTERN COUNTIES WHERE LONGER FETCH OVER THE LAKE COULD STILL SUSTAIN SOME SCATTERED SHOWER ACTIVITY. MODEL SNDGS ALSO SHOW INVERSION HEIGHTS LOWERING TO 4KFT OR LESS WITH INCREASINGLY DRIER AIR BELOW THE INVERSION BY EARLY AFTERNOON. THIS SHOULD CAUSE CLOUDS TO BREAK UP OVER WEST AND CENTRAL COUNTIES WITH INCREASING SUBSIDENCE WHICH IS ALREADY STARTING TO HAPPEN. PLAN TO UPDATE THE FORECAST MAINLY TO UPDATE THE WORDING. .EXTENDED... TONIGHT...GOOD RADIATIONAL COOLING EXPECTED WITH SFC RDG MOVING OVER AREA. LOOK FOR TEMPS TO DIP INTO THE LOW TO MID 20S FOR FAVORED INLAND COLD SPOTS. BOUNDARY LYR WINDS INCREASING TO 15-20 KT OVER THE FAR WEST OVERNIGHT COULD TEMPER COOLING SOMEWHAT BY DAYBREAK. THU...WITH THE SFC AND MID LEVEL RDG STILL OVER THE REGION WOULD EXPECT MOSTLY SUNNY SKIES. SUNSHINE AND MIXING TO 900 MB TEMPS AROUND 5C SHOULD PUSH MAX TEMPERATURES INTO THE MID TO UPPER 50S...PER GFS MOS GUIDANCE OR SLIGHTLY HIGHER. THU NIGHT...SFC RIDGE AXIS HOLD FIRM OVER THE AREA SO AGAIN EXPECT FAVORABLE RADIATIONAL COOLING ESPECIALLY OVER THE WRN INTERIOR WHERE READINGS SHOULD LOWER TOWARD GFS MOS GUIDANCE (AROUND 30F). BACKED OFF ON INCREASING CLOUDS SOME AS MODELS TRENDING SLOWER WITH ADVANCE OF SYSTEM OVER THE LOWER MISS VALLEY. FRI INTO SAT...FOLLOWING THE NCEP PREFERRED 12Z ECMWF SOLN WHICH HAS THE SUPPORT OF MODEL ENSEMBLES...BACKED OFF SOME ON TIMING OF INCREASING CLOUDS FOR FRI AS ECMWF IS SOMEWHAT SLOWER NOW THAN 00Z GFS WITH ADVANCE OF LOWER MISS VALLEY SYSTEM. STILL KEPT IN CHC OF RAIN FOR COUNTIES ALONG LAKE MI WITH SLIGHT CHC ELSEWHERE BY FRI AFTERNOON. ALSO CONTINUED GOING FCST OF CHC OF RAIN FRI NIGHT ACROSS THE CWA...BUT COULD EASILY SEE POPS BEING TRIMMED BACK IF ECMWF CONTINUES EASTWARD TREND WITH SYSTEM THROUGH THE OHIO VALLEY AND ERN GREAT LAKES. ALSO CHCS FOR LAKE EFFECT PCPN FOR SAT COULD BE DIMINISHED AS WELL WITH ECMWF TRENDING TOWARD MORE ANTICYCLONIC NRLY FLOW OVER THE AREA WITH GREATER INFLUENCE OF NRN PLAINS RIDGE. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... MVFR CIGS EXPECTED TODAY WITH WEAK LK EFFECT REGIME IN PLACE. ENOUGH COOL AIR IS ALLOWING SNOW TO MIX WITH RAIN AT KCMX AND AT OUR OFFICE IN NEGAUNEE TWP. ALTHOUGH SHOWERS REMAIN ISOLATED WITH DRY AIR JUST ABOVE CLOUD BASE...EXPECT A FEW PERIODS THIS MORNING OF MVFR VSBY IN HEAVIER SHOWERS. ENOUGH MIXING OCCURS TO LIFT CIGS TO VFR LATE TODAY AND SKIES SHOULD COMPLETELY CLEAR THIS EVENING. DID NOT INCLUDE ANY FOG FOR TONIGHT DESPITE GOOD RADIATIONAL COOLING SETUP. THINK THE LOWER LEVELS WILL REMAIN TOO DRY FOR ANY FOG FORMATION. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... GALES TO 45 KNOTS DEVELOPED IN WAKE OF COLD FRONT LATE LAST EVENING. GALES EXPECTED EARLY TODAY WITH TIGHT PRESSURE GRADIENT LINGERING BETWEEN PLAINS HIGH AND DEPARTING LOW PRESSURE SYSTEM OVER ONTARIO. PRESSURE RISE OF 6 MB/3 HR WILL ALSO SWING ACROSS THE LAKE TO HELP KEEP GALES GOING. BY THIS EVENING PRESSURE GRADIENT FALLS APART AS HIGH BUILDS FIRMLY INTO THE REGION. WINDS WILL SUBSIDE QUICKLY AND REMAIN BELOW 25 KNOTS INTO LATE FRIDAY. EXPECT ANOTHER BOUT OF STRONG TO POTENTIALLY GALE FORCE NORTHERLY WINDS LATER FRIDAY NIGHT INTO SATURDAY AS PRESSURE GRADIENT TIGHTENS BTWN PLAINS HIGH AND DEEPENING LOW OVER LOWER GREAT LAKES. WINDS DIMINISH LATER SAT NIGHT INTO SUNDAY AS HIGH PRESSURE RIDGE SETTLES OVER THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...DLG EXTENDED...VOSS AVIATION/MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 959 AM EDT WED OCT 24 2007 .UPDATE...A DAY MORE TYPICAL FOR LATE OCTOBER ACROSS THE NORTHLAND...WINDY...COOL...AND RATHER DAMP. NORTHWEST FLOW CAA CONTINUES BEHIND DEPARTING SHORTWAVE...WITH LATEST RUC ANALYSIS SHOWING 850MB TEMPERATURES RANGING FROM -6C OVER CENTRAL LAKE SUPERIOR TO -3C OVER NORTHERN LAKE MICHIGAN. THIS...COMBINED WITH LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN WATER TEMPERATURES RUNNING AT 14C AND 10C RESPECTIVELY (PER NORTHERN LAKE MICHIGAN BUOY AND GREAT LAKES SURFACE ENVIRONMENTAL ANALYSIS)...LAKE INDUCED EQUILIBRIUM LEVELS ON THE ORDER OF 6.5KFT...AND 900MB TO 700MB RH PERCENTAGES >70 PERCENT...MORE THAN SUFFICIENT TO KICK OFF LAKE EFFECT RAIN SHOWERS OVER TYPICAL NORTHWEST TO NORTH NORTHWEST FLOW AREAS. SHOWERS EVEN APPEAR TO BE GETTING A LITTLE BOOST FROM SUBTLE LAKE INDUCED SURFACE TROUGH HANGING BACK WEST JUST SOUTH OF THE STRAITS REGION. FORTUNATELY (OR UNFORTUNATELY...DEPENDING ON YOUR POINT OF VIEW) TEMPERATURES IN THE LOW TO MID 40S MAKING SURE ALL PRECIPITATION STAYS IN THE LIQUID VARIETY. FORECAST CONCERNS FOR THE REMAINDER OF THE DAY CENTER ON GRADUALLY DEMISE OF LAKE SHOWERS AND WHAT TO DO WITH CURRENT MARINE HEADLINES UNDER GUSTY MORNING WIND REGIME. ONGOING LAKE EFFECT SHOWERS SHOULD SLOWLY DECREASE IN COVERAGE AND INTENSITY AS UPSTREAM ACARS SOUNDINGS CONFIRM LATEST MODEL GUIDANCE THAT BEST MID LEVEL MOISTURE WILL GRADUALLY PEEL OFF THROUGH THE REMAINDER OF THE MORNING AND AFTERNOON AND INVERSION HEIGHTS WILL CONTINUE TO LOWER. HOWEVER...DESPITE LOSS OF SHOWER ACTIVITY BY LATER THIS AFTERNOON...DELTA T/S REMAINING IN THE UPPER TEENS SHOULD KEEP THE LAKE STRATO CU GENERATION GOING...LEADING TO MOSTLY CLOUDY SKIES OVER FAVORED NNW FLOW AREAS OF NORTHERN LOWER AND PARTLY CLOUDY SKIES ELSEWHERE. LIMITED POTENTIAL FOR SUN (ESPECIALLY ACROSS NORTHWEST LOWER) AND CONTINUING CAA SHOULD KEEP HIGHS IN THE 40S TO LOWER 50S (WARMEST NEAR THE LAKE SHORES AND FAR SOUTHEAST AREAS). MARINE...AFTER GALE CONDITIONS ACROSS LAKE MICHIGAN AND NEAR GALES OVER WHITEFISH BAY THIS MORNING...GRADUALLY WEAKENING PRESSURE GRADIENT AND LOWERING INVERSION HEIGHTS SHOULD KEEP ANY WIND GUSTS BELOW GALE CRITERIA FOR THE REMAINDER OF THE DAY. HOWEVER...WITH BUFKIT ANALYSIS SHOWING GUST POTENTIAL OF AT LEAST 25 KNOTS AND THE STILL CHOPPY CONDITIONS OVER LAKE MICHIGAN (NORTHERN BUOY WAVES RUNNING AT 6FT)...WILL REPLACE ALL GALES WITH SCA/S. ELSEWHERE... WILL MAINTAIN CURRENT ADVISORIES. UPDATED GRIDS/NEARSHORES/ZONES OUT SHORTLY. MSB && .AVIATION...ISSUED 655 AM LAKE EFFECT RAIN SHOWERS ONGOING AS COLD AIRMASS CONTINUES TO PROGRESS THROUGH THE REGION...AND WILL CONTINUE INTO EARLY AFTERNOON BEFORE HIGH PRESSURE BEGINS TO OVERTAKE THE REGION THIS EVENING. OVERALL NORTHWEST TO NORTH/NORTHWEST FLOW REGIME WILL SUPPORT BEST CHANCE FOR SHOWERS/LOWEST CEILINGS AROUND KPLN AND KTVC...WHERE PREDOMINATELY MVFR CEILINGS ARE EXPECTED. WINDS WILL CONTINUE TO BECOME GUSTY THROUGH THE DAY OUT OF THE NORTHWEST...WITH FREQUENT GUSTS IN EXCESS OF 20 KNOTS ANTICIPATED. IMPROVING CONDITIONS WILL BE NOTED BY LATE EVENING AS HIGH PRESSURE SLIDES OVERHEAD...WITH WINDS DROPPING QUICKLY TO UNDER 5 KNOTS AND SKIES BECOMING CLEAR. LAWRENCE && .PREV DISCUSSION... /ISSUED 411 AM EDT WED OCT 24 2007/ DISCUSSION...CLIPPER TYPE SYSTEM CURRENTLY ADVANCING THROUGH THE REGION THIS MORNING...WITH SURFACE COLD FRONT COMING ONSHORE FROM LAKE MICHIGAN AS OF 06Z. IN THE WAKE OF THIS SYSTEM...PLENTY COLD AIR (H85 TEMPS DROPPING TO -4C TO -6C PER UPSTREAM RAOBS) LIGHTING UP THE LAKE EFFECT MACHINE OVER LAKE SUPERIOR...LIKELY SOON TO OCCUR OFF LAKE MICHIGAN AS WELL. THE PRIMARY FORECAST CHALLENGE THROUGH THE SHORT TERM IS ADDITIONAL PRECIPITATION CHANCES TODAY AS WELL AS TEMPERATURES/WINDS. INITIAL SHOT OF PRECIP WILL BE HEADED OUT OF THE PICTURE PRIOR TO 12Z AS BEST DEEP LAYER (700-300MB) QG SUPPORT SLIPS EAST WITH THE PASSAGE OF THE UPPER TROUGH. HOWEVER...UPSTREAM RADARS INDICATIVE OF WHAT`S IN STORE THROUGH THE DAY AS THERMAL TROUGH DROPS OVER THE NORTHERN GREAT LAKES. 850MB TEMPS IN THE -4C TO -6C RANGE OBVIOUSLY MORE THAN SUFFICIENT FOR SIGNIFICANT OVERLAKE INSTABILITY (SFC-850MB DELTA T/S IN EXCESS OF 16C)...WITH TRAJECTORIES SLOWLY TRANSLATING FROM NORTHWEST EARLY THIS MORNING TO NORTH/NORTHWEST AROUND 15Z...AND THEN EVENTUALLY MORE NORTHERLY BY LATE AFTERNOON AS LOW LEVEL RIDGING QUICKLY ADVANCES TOWARD THE WESTERN U.P. IN TYPICAL LAKE EFFECT FASHION...MID/UPPER MOISTURE WILL BE ON THE WANE EARLY THIS MORNING...HOWEVER LOW LEVEL MOISTURE EXCELLENT AS 925-800MB RH HOLDS AROUND 90% THROUGH 18Z...WITH INVERSION HEIGHTS UP AROUND 6500 FEET. THUS...ANTICIPATE A CONTINUED UPTICK IN LAKE EFFECT SHOWERS THROUGH MID TO LATE MORNING AS COLDEST OF THE AIR DROPS OVERHEAD... BEFORE A RATHER ABRUPT END TO ACTIVITY BY MID TO LATE AFTERNOON AS FLOW QUICKLY BECOMES ANTICYCLONIC AND INVERSION HEIGHTS CRASH/ MOISTURE SHALLOWS WITH APPROACH OF LOW LEVEL RIDGE. HIGHS TODAY RATHER IFFY PENDING PLACEMENT OF CLOUD COVER/PRECIP...BUT WITH ONGOING COLD ADVECTION THROUGH EARLY AFTERNOON FORESEE MANY LOCATIONS AWAY FROM THE IMMEDIATE LAKE SHORES STRUGGLING THROUGH THE 40S. TONIGHT INTO THURSDAY A MUCH DIFFERENT STORY WITH INCREASINGLY DEEP LAYER RIDGING TAKING HOLD AS HEIGHTS REBOUND TO THE NORTH OF CLOSED VORTEX MEANDERING OVER THE SOUTH. WITH INCREASING SUBSIDENCE/DEEP DRYING (900-300MB RH FALLS THROUGH THE FLOOR AT 15% OR LESS)...A PERIOD OF CLEAR SKIES CERTAINLY LOOKS IN THE WORKS. GIVEN PLACEMENT OF LOW LEVEL RIDGE AXIS OVER THE CWA TONIGHT...APPEARS TEMPERATURES WILL BE QUITE COLD - PERHAPS THE COLDEST YET THIS SEASON - WITH READINGS WELL INTO THE 20S FOR THE NORMALLY COLDER VALLEYS GIVEN ALREADY COOL START EXPECTED BY EARLY EVENING. PLENTY OF SUNSHINE ON THURSDAY WITH INCREASING WARM ADVECTION INTO THE AFTERNOON SHOULD LEAD TO QUITE THE SEASONABLE DAY...WITH HIGHS WELL INTO THE 50S IF NOT NEAR 60 IN A FEW SPOTS. MARINE ISSUES...AS ANTICIPATED...SEEING A QUICK UPTICK IN WINDS OVER THE LAKES AS COLD ADVECTION ENSUES AND CORE OF STRONGEST 900-800MB WINDS ADVANCES THROUGH INCREASINGLY MIXED LAYER. PER UPSTREAM VAD WIND PLOTS AND 06Z RUC ANALYSIS...APPEARS STRONGEST CORE OF WINDS WILL SLIDE THROUGH THE REGION BETWEEN NOW AND 15Z...DIMINISHING RATHER QUICKLY THEREAFTER. SOME QUESTION ABOUT ACHIEVABILITY OF GALES THIS MORNING FOR WHITEFISH BAY/LAKE MICHIGAN...NAMELY GIVEN ROUGHLY 35 KNOTS (MAYBE BRIEFLY HIGHER) THROUGH THE MIXED LAYER AS BEST CORE WINDS SLIDES BY TO THE WEST...HOWEVER MID LAKE BUOY IN NORTHERN MICHIGAN ALREADY PEAKING AROUND 33 KNOTS...SO WILL OBVIOUSLY LEAVE GOING MENTION IN PLACE AS THINGS SHOULD TREND UP JUST A BIT THROUGH 12Z. ELSEWHERE...SMALL CRAFT CONDITIONS A NEAR CERTAINTY THROUGH LATE AFTERNOON (INCLUDING LOCATIONS WHERE CURRENT GALES ALREADY UP)...WITH WINDS ALL LOCATIONS DIMINISHING RATHER QUICKLY THIS EVENING AS HIGH PRESSURE TAKES OVER. LATER PERIODS (THURSDAY NIGHT THROUGH SUNDAY)...MODEL GUIDANCE CONTINUES TO ATTEMPT TO LOCK ONTO A SOLUTION REGARDING THE SOUTHERN CLOSED LOW...WHICH WILL HAVE A BIG IMPACT ON THE LATE WEEK/WEEKEND WEATHER OVER NORTHERN MICHIGAN. 00Z GFS/GFS ENSEMBLE MEAN/CANADIAN AND 12Z ECMWF REMAIN IN QUITE GOOD AGREEMENT DEPICTING A GRADUAL SHIFT OF THE CYCLONE TOWARD THE LOWER GREAT LAKES BY SATURDAY AS ADDITIONAL NORTHERN STREAM ENERGY PROGRESSING THROUGH THE ROCKIES YIELDS A WEAKNESS IN THE MID LEVEL FLOW SUFFICIENT TO "CATCH" THE SYSTEM. SHOULD THIS SCENARIO OCCUR...INCREASINGLY DIVERGENT MID LEVEL FLOW COUPLED WITH AMPLE ATLANTIC MOISTURE AND INCREASING ISENTROPIC UPGLIDE AS TONGUE OF WARM ADVECTION WRAPS NORTH AHEAD OF THE GYRE WOULD CERTAINLY BE SUFFICIENT TO PRODUCE PRECIPITATION. CURRENT FORECAST ALREADY SUPPORTS CHANCES FOR RAIN FRIDAY THROUGH SUNDAY TIMEFRAME AND THIS LOOKS GOOD GIVEN REMAINING UNCERTAINTIES. LAWRENCE && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 655 AM EDT WED OCT 24 2007 .AVIATION...LAKE EFFECT RAIN SHOWERS ONGOING AS COLD AIRMASS CONTINUES TO PROGRESS THROUGH THE REGION...AND WILL CONTINUE INTO EARLY AFTERNOON BEFORE HIGH PRESSURE BEGINS TO OVERTAKE THE REGION THIS EVENING. OVERALL NORTHWEST TO NORTH/NORTHWEST FLOW REGIME WILL SUPPORT BEST CHANCE FOR SHOWERS/LOWEST CEILINGS AROUND KPLN AND KTVC...WHERE PREDOMINATELY MVFR CEILINGS ARE EXPECTED. WINDS WILL CONTINUE TO BECOME GUSTY THROUGH THE DAY OUT OF THE NORTHWEST...WITH FREQUENT GUSTS IN EXCESS OF 20 KNOTS ANTICIPATED. IMPROVING CONDITIONS WILL BE NOTED BY LATE EVENING AS HIGH PRESSURE SLIDES OVERHEAD...WITH WINDS DROPPING QUICKLY TO UNDER 5 KNOTS AND SKIES BECOMING CLEAR. LAWRENCE && .PREV DISCUSSION... /ISSUED 411 AM EDT WED OCT 24 2007/ DISCUSSION...CLIPPER TYPE SYSTEM CURRENTLY ADVANCING THROUGH THE REGION THIS MORNING...WITH SURFACE COLD FRONT COMING ONSHORE FROM LAKE MICHIGAN AS OF 06Z. IN THE WAKE OF THIS SYSTEM...PLENTY COLD AIR (H85 TEMPS DROPPING TO -4C TO -6C PER UPSTREAM RAOBS) LIGHTING UP THE LAKE EFFECT MACHING OVER LAKE SUPERIOR...LIKELY SOON TO OCCUR OFF LAKE MICHIGAN AS WELL. THE PRIMARY FORECAST CHALLENGE THROUGH THE SHORT TERM IS ADDITIONAL PRECIPITATION CHANCES TODAY AS WELL AS TEMPERATURES/WINDS. INITIAL SHOT OF PRECIP WILL BE HEADED OUT OF THE PICTURE PRIOR TO 12Z AS BEST DEEP LAYER (700-300MB) QG SUPPORT SLIPS EAST WITH THE PASSAGE OF THE UPPER TROUGH. HOWEVER...UPSTREAM RADARS INDICATIVE OF WHAT`S IN STORE THROUGH THE DAY AS THERMAL TROUGH DROPS OVER THE NORTHERN GREAT LAKES. 850MB TEMPS IN THE -4C TO -6C RANGE OBVIOUSLY MORE THAN SUFFICIENT FOR SIGNIFICANT OVERLAKE INSTABILITY (SFC-850MB DELTA T/S IN EXCESS OF 16C)...WITH TRAJECTORIES SLOWLY TRANSLATING FROM NORTHWEST EARLY THIS MORNING TO NORTH/NORTHWEST AROUND 15Z...AND THEN EVENTUALLY MORE NORTHERLY BY LATE AFTERNOON AS LOW LEVEL RIDGING QUICKLY ADVANCES TOWARD THE WESTERN U.P. IN TYPICAL LAKE EFFECT FASHION...MID/UPPER MOISTURE WILL BE ON THE WANE EARLY THIS MORNING...HOWEVER LOW LEVEL MOISTURE EXCELLENT AS 925-800MB RH HOLDS AROUND 90% THROUGH 18Z...WITH INVERSION HEIGHTS UP AROUND 6500 FEET. THUS...ANTICIPATE A CONTINUED UPTICK IN LAKE EFFECT SHOWERS THROUGH MID TO LATE MORNING AS COLDEST OF THE AIR DROPS OVERHEAD... BEFORE A RATHER ABRUPT END TO ACTIVITY BY MID TO LATE AFTERNOON AS FLOW QUICKLY BECOMES ANTICYCLONIC AND INVERSION HEIGHTS CRASH/ MOISTURE SHALLOWS WITH APPROACH OF LOW LEVEL RIDGE. HIGHS TODAY RATHER IFFY PENDING PLACEMENT OF CLOUD COVER/PRECIP...BUT WITH ONGOING COLD ADVECTION THROUGH EARLY AFTERNOON FORESEE MANY LOCATIONS AWAY FROM THE IMMEDIATE LAKE SHORES STRUGGLING THROUGH THE 40S. TONIGHT INTO THURSDAY A MUCH DIFFERENT STORY WITH INCREASINGLY DEEP LAYER RIDGING TAKING HOLD AS HEIGHTS REBOUND TO THE NORTH OF CLOSED VORTEX MEANDERING OVER THE SOUTH. WITH INCREASING SUBSIDENCE/DEEP DRYING (900-300MB RH FALLS THROUGH THE FLOOR AT 15% OR LESS)...A PERIOD OF CLEAR SKIES CERTAINLY LOOKS IN THE WORKS. GIVEN PLACEMENT OF LOW LEVEL RIDGE AXIS OVER THE CWA TONIGHT...APPEARS TEMPERATURES WILL BE QUITE COLD - PERHAPS THE COLDEST YET THIS SEASON - WITH READINGS WELL INTO THE 20S FOR THE NORMALLY COLDER VALLEYS GIVEN ALREADY COOL START EXPECTED BY EARLY EVENING. PLENTY OF SUNSHINE ON THURSDAY WITH INCREASING WARM ADVECTION INTO THE AFTERNOON SHOULD LEAD TO QUITE THE SEASONABLE DAY...WITH HIGHS WELL INTO THE 50S IF NOT NEAR 60 IN A FEW SPOTS. MARINE ISSUES...AS ANTICIPATED...SEEING A QUICK UPTICK IN WINDS OVER THE LAKES AS COLD ADVECTION ENSUES AND CORE OF STRONGEST 900-800MB WINDS ADVANCES THROUGH INCREASINGLY MIXED LAYER. PER UPSTREAM VAD WIND PLOTS AND 06Z RUC ANALYSIS...APPEARS STRONGEST CORE OF WINDS WILL SLIDE THROUGH THE REGION BETWEEN NOW AND 15Z...DIMINISHING RATHER QUICKLY THEREAFTER. SOME QUESTION ABOUT ACHIEVABILITY OF GALES THIS MORNING FOR WHITEFISH BAY/LAKE MICHIGAN...NAMELY GIVEN ROUGHLY 35 KNOTS (MAYBE BRIEFLY HIGHER) THROUGH THE MIXED LAYER AS BEST CORE WINDS SLIDES BY TO THE WEST...HOWEVER MID LAKE BUOY IN NORTHERN MICHIGAN ALREADY PEAKING AROUND 33 KNOTS...SO WILL OBVIOUSLY LEAVE GOING MENTION IN PLACE AS THINGS SHOULD TREND UP JUST A BIT THROUGH 12Z. ELSEWHERE...SMALL CRAFT CONDITIONS A NEAR CERTAINTY THROUGH LATE AFTERNOON (INCLUDING LOCATIONS WHERE CURRENT GALES ALREADY UP)...WITH WINDS ALL LOCATIONS DIMINISHING RATHER QUICKLY THIS EVENING AS HIGH PRESSURE TAKES OVER. LATER PERIODS (THURSDAY NIGHT THROUGH SUNDAY)...MODEL GUIDANCE CONTINUES TO ATTEMPT TO LOCK ONTO A SOLUTION REGARDING THE SOUTHERN CLOSED LOW...WHICH WILL HAVE A BIG IMPACT ON THE LATE WEEK/WEEKEND WEATHER OVER NORTHERN MICHIGAN. 00Z GFS/GFS ENSEMBLE MEAN/CANADIAN AND 12Z ECMWF REMAIN IN QUITE GOOD AGREEMENT DEPICTING A GRADUAL SHIFT OF THE CYCLONE TOWARD THE LOWER GREAT LAKES BY SATURDAY AS ADDITIONAL NORTHERN STREAM ENERGY PROGRESSING THROUGH THE ROCKIES YIELDS A WEAKNESS IN THE MID LEVEL FLOW SUFFICIENT TO "CATCH" THE SYSTEM. SHOULD THIS SCENARIO OCCUR...INCREASINGLY DIVERGENT MID LEVEL FLOW COUPLED WITH AMPLE ATLANTIC MOISTURE AND INCREASING ISENTROPIC UPGLIDE AS TONGUE OF WARM ADVECTION WRAPS NORTH AHEAD OF THE GYRE WOULD CERTAINLY BE SUFFICIENT TO PRODUCE PRECIPITATION. CURRENT FORECAST ALREADY SUPPORTS CHANCES FOR RAIN FRIDAY THROUGH SUNDAY TIMEFRAME AND THIS LOOKS GOOD GIVEN REMAINING UNCERTAINTIES. LAWRENCE && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LMZ323-342-344>346. LH...NONE. LS...GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LSZ321. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 530 AM EDT WED OCT 24 2007 .DISCUSSION... MAIN FCST ISSUES INCLUDE DIMINISHING TREND OF LAKE EFFECT SHOWERS DOWNWIND OF LAKE SUPERIOR TODAY THEN RAIN CHANCES FRI INTO SAT AS SYSTEM OVER THE LOWER MISSISSIPPI VALLEY LIFTS SLOWLY TOWARD THE GREAT LAKES/OHIO VALLEY. WATER VAPOR LOOP AND RUC ANALYSIS SHOWS THAT THE MID-UPR TROF AXIS HAS MOVED EAST OF THE FCST AREA. FAIRLY TIGHT NRLY GRADIENT PERSISTS EARLY THIS MORNING BETWEEN ASSOC SFC LOW CENTERED NEAR THE SOO AND HIGH PRES RIDGE OVER THE NRN PLAINS. PRES RISE MAX OF 5+ MB MOVING OVER LAKE SUPERIOR ALONG WITH CAA (8H TEMPS LOWERING TO -6/-7C) IN WAKE OF TROF/COLD FRONT ENHANCING GALES FORCE WINDS OVER CENTRAL AND EASTERN LAKE SUPERIOR WITH GUSTS TO 40 KT. CAA AND ASSOC INSTABILITY ALSO GENERATING LAKE EFFECT RAIN SHOWERS WITH BEST COVERAGE ATTM OVER CENTRAL AND ERN LAKE SUPERIOR. TODAY...LOOK FOR SCATTERED SHOWERS TO QUICKLY DIMINISH AFTER 12Z AS RIDGING STARTS TO BUILD IN FROM WEST AND FLOW BECOMES INCREASINGLY ANTICYCLONIC. SHOWERS SHOULD END BY AFTERNOON FOR ALL BUT THREE ERN COUNTIES WHERE LONGER FETCH OVER THE LAKE COULD STILL SUSTAIN SOME SCT SHOWER ACTIVITY. MODEL SNDGS ALSO SHOW INVERSION HEIGHTS LOWERING TO 4KFT OR LESS WITH INCREASINGLY DRIER AIR BLO THE INVERSION BY LATE MORNING/EARLY AFTERNOON. SHOULD ALSO SEE A CLOUDS BREAKING UP OVER WEST AND CENTRAL COUNTIES WITH INCREASING SUBSIDENCE. TONIGHT...GOOD RADIATIONAL COOLING EXPECTED WITH SFC RDG MOVING OVER AREA. LOOK FOR TEMPS TO DIP INTO THE LOW TO MID 20S FOR FAVORED INLAND COLD SPOTS. BOUNDARY LYR WINDS INCREASING TO 15-20 KT OVER THE FAR WEST OVERNIGHT COULD TEMPER COOLING SOMEWHAT BY DAYBREAK. THU...WITH THE SFC AND MID LEVEL RDG STILL OVER THE REGION WOULD EXPECT MOSTLY SUNNY SKIES. SUNSHINE AND MIXING TO 900 MB TEMPS AROUND 5C SHOULD PUSH MAX TEMPERATURES INTO THE MID TO UPPER 50S...PER GFS MOS GUIDANCE OR SLIGHTLY HIGHER. THU NIGHT...SFC RIDGE AXIS HOLD FIRM OVER THE AREA SO AGAIN EXPECT FAVORABLE RADIATIONAL COOLING ESPECIALLY OVER THE WRN INTERIOR WHERE READINGS SHOULD LOWER TOWARD GFS MOS GUIDANCE (AROUND 30F). BACKED OFF ON INCREASING CLOUDS SOME AS MODELS TRENDING SLOWER WITH ADVANCE OF SYSTEM OVER THE LOWER MISS VALLEY. FRI INTO SAT...FOLLOWING THE NCEP PREFERRED 12Z ECMWF SOLN WHICH HAS THE SUPPORT OF MODEL ENSEMBLES...BACKED OFF SOME ON TIMING OF INCREASING CLOUDS FOR FRI AS ECMWF IS SOMEWHAT SLOWER NOW THAN 00Z GFS WITH ADVANCE OF LOWER MISS VALLEY SYSTEM. STILL KEPT IN CHC OF RAIN FOR COUNTIES ALONG LAKE MI WITH SLIGHT CHC ELSEWHERE BY FRI AFTERNOON. ALSO CONTINUED GOING FCST OF CHC OF RAIN FRI NIGHT ACROSS THE CWA...BUT COULD EASILY SEE POPS BEING TRIMMED BACK IF ECMWF CONTINUES EASTWARD TREND WITH SYSTEM THROUGH THE OHIO VALLEY AND ERN GREAT LAKES. ALSO CHCS FOR LAKE EFFECT PCPN FOR SAT COULD BE DIMINISHED AS WELL WITH ECMWF TRENDING TOWARD MORE ANTICYCLONIC NRLY FLOW OVER THE AREA WITH GREATER INFLUENCE OF NRN PLAINS RIDGE. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... MVFR CONDITIONS WILL CONTINUE INTO WED AFTERNOON WITH THE RAIN SHOWERS WITH SOME LAKE EFFECT CLOUDS THROWN INTO THE MIX. REMOVED SNOW FROM THE FORECAST TONIGHT AS NAM SOUNDINGS DO NOT SHOW IT...GFS STILL DOES AT KSAW AND KCMX. THINK THE GFS IS TOO COLD AT THE LOW LEVELS AND BELIEVE THE NAM IS DOING A BETTER JOB...SO PCPN SHOULD REMAIN AS RAIN AND NOT RESTRICTIONS TO VISIBILITY ARE EXPECTED AT EITHER PLACE. VFR CONDITIONS WILL RETURN TO KCMX AND KSAW TOWARDS THE LATE AFTERNOON WITH DRIER AIR COMING INTO THE AREA AND LIGHTER WINDS. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... GALES TO 45 KNOTS DEVELOPED IN WAKE OF COLD FRONT LATE LAST EVENING. GALES EXPECTED EARLY TODAY WITH TIGHT PRESSURE GRADIENT LINGERING BETWEEN PLAINS HIGH AND DEPARTING LOW PRESSURE SYSTEM OVER ONTARIO. PRESSURE RISE OF 6 MB/3 HR WILL ALSO SWING ACROSS THE LAKE TO HELP KEEP GALES GOING. BY THIS EVENING PRESSURE GRADIENT FALLS APART AS HIGH BUILDS FIRMLY INTO THE REGION. WINDS WILL SUBSIDE QUICKLY AND REMAIN BELOW 25 KNOTS INTO LATE FRIDAY. EXPECT ANOTHER BOUT OF STRONG TO POTENTIALLY GALE FORCE NORTHERLY WINDS LATER FRIDAY NIGHT INTO SATURDAY AS PRESSURE GRADIENT TIGHTENS BTWN PLAINS HIGH AND DEEPENING LOW OVER LOWER GREAT LAKES. WINDS DIMINISH LATER SAT NIGHT INTO SUNDAY AS HIGH PRESSURE RIDGE SETTLES OVER THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING TIL 8 AM EDT TODAY LSZ243>245-263>265 GALE WARNING TIL 10 AM EDT TODAY LSZ249>251-266-267 && $$ DISCUSSION...VOSS AVIATION...MICHELS MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 411 AM EDT WED OCT 24 2007 .DISCUSSION...CLIPPER TYPE SYSTEM CURRENTLY ADVANCING THROUGH THE REGION THIS MORNING...WITH SURFACE COLD FRONT COMING ONSHORE FROM LAKE MICHIGAN AS OF 06Z. IN THE WAKE OF THIS SYSTEM...PLENTY COLD AIR (H85 TEMPS DROPPING TO -4C TO -6C PER UPSTREAM RAOBS) LIGHTING UP THE LAKE EFFECT MACHING OVER LAKE SUPERIOR...LIKELY SOON TO OCCUR OFF LAKE MICHIGAN AS WELL. THE PRIMARY FORECAST CHALLENGE THROUGH THE SHORT TERM IS ADDITIONAL PRECIPITATION CHANCES TODAY AS WELL AS TEMPERATURES/WINDS. INITIAL SHOT OF PRECIP WILL BE HEADED OUT OF THE PICTURE PRIOR TO 12Z AS BEST DEEP LAYER (700-300MB) QG SUPPORT SLIPS EAST WITH THE PASSAGE OF THE UPPER TROUGH. HOWEVER...UPSTREAM RADARS INDICATIVE OF WHAT`S IN STORE THROUGH THE DAY AS THERMAL TROUGH DROPS OVER THE NORTHERN GREAT LAKES. 850MB TEMPS IN THE -4C TO -6C RANGE OBVIOUSLY MORE THAN SUFFICIENT FOR SIGNIFICANT OVERLAKE INSTABILITY (SFC-850MB DELTA T/S IN EXCESS OF 16C)...WITH TRAJECTORIES SLOWLY TRANSLATING FROM NORTHWEST EARLY THIS MORNING TO NORTH/NORTHWEST AROUND 15Z...AND THEN EVENTUALLY MORE NORTHERLY BY LATE AFTERNOON AS LOW LEVEL RIDGING QUICKLY ADVANCES TOWARD THE WESTERN U.P. IN TYPICAL LAKE EFFECT FASHION...MID/UPPER MOISTURE WILL BE ON THE WANE EARLY THIS MORNING...HOWEVER LOW LEVEL MOISTURE EXCELLENT AS 925-800MB RH HOLDS AROUND 90% THROUGH 18Z...WITH INVERSION HEIGHTS UP AROUND 6500 FEET. THUS...ANTICIPATE A CONTINUED UPTICK IN LAKE EFFECT SHOWERS THROUGH MID TO LATE MORNING AS COLDEST OF THE AIR DROPS OVERHEAD... BEFORE A RATHER ABRUPT END TO ACTIVITY BY MID TO LATE AFTERNOON AS FLOW QUICKLY BECOMES ANTICYCLONIC AND INVERSION HEIGHTS CRASH/ MOISTURE SHALLOWS WITH APPROACH OF LOW LEVEL RIDGE. HIGHS TODAY RATHER IFFY PENDING PLACEMENT OF CLOUD COVER/PRECIP...BUT WITH ONGOING COLD ADVECTION THROUGH EARLY AFTERNOON FORESEE MANY LOCATIONS AWAY FROM THE IMMEDIATE LAKE SHORES STRUGGLING THROUGH THE 40S. TONIGHT INTO THURSDAY A MUCH DIFFERENT STORY WITH INCREASINGLY DEEP LAYER RIDGING TAKING HOLD AS HEIGHTS REBOUND TO THE NORTH OF CLOSED VORTEX MEANDERING OVER THE SOUTH. WITH INCREASING SUBSIDENCE/DEEP DRYING (900-300MB RH FALLS THROUGH THE FLOOR AT 15% OR LESS)...A PERIOD OF CLEAR SKIES CERTAINLY LOOKS IN THE WORKS. GIVEN PLACEMENT OF LOW LEVEL RIDGE AXIS OVER THE CWA TONIGHT...APPEARS TEMPERATURES WILL BE QUITE COLD - PERHAPS THE COLDEST YET THIS SEASON - WITH READINGS WELL INTO THE 20S FOR THE NORMALLY COLDER VALLEYS GIVEN ALREADY COOL START EXPECTED BY EARLY EVENING. PLENTY OF SUNSHINE ON THURSDAY WITH INCREASING WARM ADVECTION INTO THE AFTERNOON SHOULD LEAD TO QUITE THE SEASONABLE DAY...WITH HIGHS WELL INTO THE 50S IF NOT NEAR 60 IN A FEW SPOTS. MARINE ISSUES...AS ANTICIPATED...SEEING A QUICK UPTICK IN WINDS OVER THE LAKES AS COLD ADVECTION ENSUES AND CORE OF STRONGEST 900-800MB WINDS ADVANCES THROUGH INCREASINGLY MIXED LAYER. PER UPSTREAM VAD WIND PLOTS AND 06Z RUC ANALYSIS...APPEARS STRONGEST CORE OF WINDS WILL SLIDE THROUGH THE REGION BETWEEN NOW AND 15Z...DIMINISHING RATHER QUICKLY THEREAFTER. SOME QUESTION ABOUT ACHIEVABILITY OF GALES THIS MORNING FOR WHITEFISH BAY/LAKE MICHIGAN...NAMELY GIVEN ROUGHLY 35 KNOTS (MAYBE BRIEFLY HIGHER) THROUGH THE MIXED LAYER AS BEST CORE WINDS SLIDES BY TO THE WEST...HOWEVER MID LAKE BUOY IN NORTHERN MICHIGAN ALREADY PEAKING AROUND 33 KNOTS...SO WILL OBVIOUSLY LEAVE GOING MENTION IN PLACE AS THINGS SHOULD TREND UP JUST A BIT THROUGH 12Z. ELSEWHERE...SMALL CRAFT CONDITIONS A NEAR CERTAINTY THROUGH LATE AFTERNOON (INCLUDING LOCATIONS WHERE CURRENT GALES ALREADY UP)...WITH WINDS ALL LOCATIONS DIMINISHING RATHER QUICKLY THIS EVENING AS HIGH PRESSURE TAKES OVER. LATER PERIODS (THURSDAY NIGHT THROUGH SUNDAY)...MODEL GUIDANCE CONTINUES TO ATTEMPT TO LOCK ONTO A SOLUTION REGARDING THE SOUTHERN CLOSED LOW...WHICH WILL HAVE A BIG IMPACT ON THE LATE WEEK/WEEKEND WEATHER OVER NORTHERN MICHIGAN. 00Z GFS/GFS ENSEMBLE MEAN/CANADIAN AND 12Z ECMWF REMAIN IN QUITE GOOD AGREEMENT DEPICTING A GRADUAL SHIFT OF THE CYCLONE TOWARD THE LOWER GREAT LAKES BY SATURDAY AS ADDITIONAL NORTHERN STREAM ENERGY PROGRESSING THROUGH THE ROCKIES YIELDS A WEAKNESS IN THE MID LEVEL FLOW SUFFICIENT TO "CATCH" THE SYSTEM. SHOULD THIS SCENARIO OCCUR...INCREASINGLY DIVERGENT MID LEVEL FLOW COUPLED WITH AMPLE ATLANTIC MOISTURE AND INCREASING ISENTROPIC UPGLIDE AS TONGUE OF WARM ADVECTION WRAPS NORTH AHEAD OF THE GYRE WOULD CERTAINLY BE SUFFICIENT TO PRODUCE PRECIPITATION. CURRENT FORECAST ALREADY SUPPORTS CHANCES FOR RAIN FRIDAY THROUGH SUNDAY TIMEFRAME AND THIS LOOKS GOOD GIVEN REMAINING UNCERTAINTIES. LAWRENCE && .AVIATION... /ISSUED 203 AM EDT WED OCT 24 2007/ SHOWERS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF A COLD FRONT ASSOCIATED WITH A FAST-MOVING LOW PRESSURE SYSTEM. THESE SHOWERS WILL IMPACT ALL TAF SITES OVERNIGHT...WITH PATCHES OF MVFR CIGS AND VSBYS EXPECTED WITHIN THE SHOWERS. COLD AIR BEHIND THE FRONT WILL AID IN THE DEVELOPMENT OF LAKE EFFECT RAIN SHOWERS TOWARD DAYBREAK. LAKE EFFECT RAIN SHOWERS WILL CONTINUE THRU MUCH OF TODAY...IMPACTING MAINLY TVC/PLN WITH MVFR CONDITIONS AT TIMES. VFR CONDITIONS AND DRY WX WILL RETURN TO ALL OF NRN LOWER MICHIGAN FOR LATE AFTERNOON AND EVENING. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LMZ323-342-344>346. LH...NONE. LS...GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LSZ321. && $$ mi AREA FORECAST DISCUSSION...UPDATED FOR AVIATION NATIONAL WEATHER SERVICE MARQUETTE MI 135 AM EDT WED OCT 24 2007 .SYNOPSIS... WATER VAPOR IMAGERY AND RUC SHOWING A CLOSED LOW EMBEDDED IN THE BASE OF A LONG WAVE TROUGH OVER THE UPPER GREAT LAKES. THE TROUGH EXTENDS FROM A JAMES BAY SOUTHWEST ACROSS CENTRAL UPPER MICHIGAN TO THE LOW OVER SOUTHEAST ARKANSAS. A BROAD RIDGE BLANKETS THE ROCKIES. A SHORTWAVE SLIDING DOWN THE LEE OF THE RIDGE IS OVER THE MINNESOTA ARROWHEAD POISED TO ENTER INTO LAKE SUPERIOR AND WESTERN U.P. SURFACE ANALYSIS DEPICTS A LOW OVER SOUTHERN HUDSON BAY WITH A COLD FRONT DRAPED SOUTHWEST THROUGH CENTRAL LAKE SUPERIOR AND ACROSS THE WESTERN U.P. .SHORT TERM... THE MID LEVEL TROUGH OVER THE UPPER GREAT LAKES WILL MOVE TO SOUTHEAST MICHIGAN AND THE LOWER GREAT LAKES TONIGHT AND WEDNESDAY. THE MINNESOTA SHORTWAVE WILL SAIL SOUTHEAST INTO SOUTHEAST MICHIGAN TONIGHT. THE COLD FRONT WILL SETTLE INTO NORTHWEST LOWER MICHIGAN BY MIDNIGHT TONIGHT AND OVER THE KDET BY SUNRISE. GUIDANCE SHOWING DEEP MOISTURE ACCOMPANYING THE LOW WILL SHIFT OVER THE AREA TONIGHT. THUS Q-VECTOR CONVERGENCE ACCOMPANYING THE SHORTWAVE AND ISENTROPIC ASCENT WITH THE FRONTAL SYSTEM WILL SQUEEZE SOME OF THE MOISTURE OUT OF THE AREA OF DEEP MOISTURE AND PRODUCE SCATTERED SHOWERS AREA THE U.P. THIS EVENING AND NUMEROUS SHOWERS INTO WESTERN AND NORTH CENTRAL LAKE SUPERIOR. RAIN IS ALREADY ACCOMPANYING THIS ACTIVITY OVER NORTHERN MINNESOTA...WESTERN ONTARIO...AND THE KCMX AREA. A DOME OF HIGH PRESSURE WILL MOVE OUT OF THE NORTHERN HIGH PLAINS ON WEDNESDAY AND OVER THE FORECAST AREA WEDNESDAY AFTERNOON. AN 850MB THERMAL TROUGH WILL SIDE OVER EASTERN LAKE SUPERIOR LATE TONIGHT AND WEDNESDAY PRODUCING A LAKE-850MB DELTA-T OF 14C. WINDS WILL BE OUT OF THE NORTHWEST THROUGH EARLY AFTERNOON. THUS WILL PRODUCE COLD ENOUGH TEMPERATURES AND A LONG ENOUGH FETCH TO DEVELOP A FEW LAKE EFFECT RAINS OVER THE EASTERN U.P. IN THE AFTERNOON. TIGHT GRADIENTS AHEAD OF THE HIGH WILL PRODUCE SOME STRONGER WINDS OVERNIGHT. SEE THE MARINE DISCUSSION BELOW. && .LONG TERM...(WED NIGHT THROUGH TUESDAY) MAIN FCST CONCERNS ARE RAIN CHANCES FRI INTO SAT FOLLOWED BY LAKE EFFECT PCPN POTENTIAL INTO EARLY SUN. WED NIGHT...VERY GOOD RADIATIONAL COOLING CONDITIONS WITH A SFC RDG MOVING INTO THE AREA WILL ALLOW TEMPS TO DROP INTO THE UPPER 20S INLAND. EVEN THOUGH SSW BOUNDARY LAYER WINDS TO 15-20 KT MOVE INTO THE NW HALF OVERNIGHT...PER 12Z NAM...SFC WINDS WILL DECOUPLE DURING THE EVENING WITH TEMPS ONLY RISING SLIGHTLY TOWARD DAYBREAK. THU...THE SFC AND MID LEVEL RDG REMAIN IN PLACE KEEPING SKIES MOSTLY SUNNY. SUNSHINE AND MIXING TO 900 MB TEMPS AROUND 5C SHOULD PUSH MAX TEMPERATURES INTO THE MID TO UPPER 50S. FRI INTO SAT...THE MODELS HAVE TRENDED TOWARD A MORE PROGRESSIVE SOLUTION WITH A FASTER NRN STREAM SHORTWAVE HELPING TO KICK THE CUTOFF LOW MORE QUICKLY TO THE NORTHEAST. THE FCST LEANED MORE TOWARD THE 12Z CANADIAN GLOBAL GEM WHICH OFFERED A REASONABLE COMPROMISE BTWN THE FASTER GFS AND SLOWER 12ZUKMET/00ZECMWF. THE 12Z ECMWF HAS ALSO COME INTO REASONABLE AGREEMENT WITH THE CANADIAN MDL TIMING BUT WAS A BIT FARTHER SOUTH AT 12Z/SAT. EXPECT A BAND OF PCPN SUPPORTED BY MID LEVEL DEFORMATION ZONE TO SLOWLY SPREAD FROM SE TO NW TOWARD AND INTO THE CWA IF THE MID LEVEL LOW MOVES FAR ENOUGH NORTH. WITH REMAINING UNCERTAINTY WITH THE PLACEMENT OF THE LOW AND WEST/CNTRL UPPER MI MAINLY ON THE EDGE OF THE FCST PCPN SHIELD...ONLY LOWER END POPS WERE POPS WERE MENTIONED...GREATEST OVER THE SOUTHEAST. AS THE NRN STREAM SHORTWAVE MOVES IN IT SHOULD BRING IN ENOUGH COLD AIR...WITH 850 MB TEMPS DOWN TO -6C TO -8C AND 1000-850 MB THICKNESS VALUES BLO 1305M FOR POTENTIAL OF SNOW SHOWERS OVER HIGHER TERRAIN FROM LATE FRI NIGHT INTO EARLY SUN. MODELS TREND TOWARD WNW FLOW PATTERN IS EXPECTED TO ALLOW THE SFC RDG TO BUILD IN WITH BACKING WINDS AND WAA...BRINGING AN END TO LAKE EFFECT PCPN BY SUN AFTERNOON. MON-TUE...THE FCST LEANED MORE TOWARD THE 00Z ECMWF WHICH MAINTAINED WNW MID/UPPER LEVEL FLOW TOWARD THE GREAT LAKES. DIFFERENCES WITH THE GFS WHICH TRENDS TOWARD MORE SW FLOW STEM IN PART FROM POSITION OF THE MID LEVEL LOW OVER THE ERN PACIFIC. EVEN WITH LOW CONFIDENCE IN DETAILS OF THE PATTERN NEXT WEEK...MAIN SUPPORT FOR PCPN WOULD BE WAA AHEAD OF LOW PRES MOVING THROUGH NRN SASK/MANITOBA/ONTARIO AND A TROF/FRONT THROUGH THE WRN LAKES. WITH ONLY LIMITED OPPORTUNITY FOR MOISTURE INFLOW...FCST DID NOT INCLUDE MENTION OF PCPN. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... MVFR CONDITIONS WILL CONTINUE INTO WED AFTERNOON WITH THE RAIN SHOWERS WITH SOME LAKE EFFECT CLOUDS THROWN INTO THE MIX. REMOVED SNOW FROM THE FORECAST TONIGHT AS NAM SOUNDINGS DO NOT SHOW IT...GFS STILL DOES AT KSAW AND KCMX. THINK THE GFS IS TOO COLD AT THE LOW LEVELS AND BELIEVE THE NAM IS DOING A BETTER JOB...SO PCPN SHOULD REMAIN AS RAIN AND NOT RESTRICTIONS TO VISIBILITY ARE EXPECTED AT EITHER PLACE. VFR CONDITIONS WILL RETURN TO KCMX AND KSAW TOWARDS THE LATE AFTERNOON WITH DRIER AIR COMING INTO THE AREA AND LIGHTER WINDS. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... THE TIGHT GRADIENT BETWEEN THE HIGH MOVING OUT THE PLAINS AND THE COLD FRONT MOVING THROUGH THE FORECAST AREA TONIGHT COUPLED WITH STRONG COLD ADVECTION BEHIND THE FRONT WILL RESULT IN NW TO N GALES TO 35-40 KT ACROSS MOST OF LAKE SUPERIOR. WINDS WILL BEGIN TO SUBSIDE FROM THE WEST ON WEDNESDAY AS RIDGING BUILDS IN FROM THE NORTHERN PLAINS. SOUTHWEST WINDS WILL INCREASE TO 25 KT LATE WED NIGHT INTO THURSDAY AHEAD OF ANOTHER FRONTAL SYSTEM MOVING THROUGH SOUTH CENTRAL CANADA. WINDS WILL GENERALLY DIMINISH BELOW 15 KT LATE THURSDAY NIGHT INTO FRIDAY AS WEAK HIGH PRESSURE BUILDS OVER THE AREA. NORTH WINDS WILL PICK UP TO NEAR 30 KT AGAIN LATE FRIDAY INTO SATURDAY AS THE GRADIENT TIGHTENS BETWEEN A LOW PRESSURE CENTER MOVING INTO THE EASTERN GREAT LAKES AND STRENGTHENING HIGH PRESSURE OVER THE NORTHERN PLAINS. ON SATURDAY ANOTHER RIDGE WILL MOVE OUT OF THE NORTHERN PLAINS OVER THE UPPER GREAT LAKES WEAKENING THE GRADIENTS AGAIN. && .MQT WATCHES/WARNINGS/ADVISORIES...GALE WARNING FOR LAKE SUPERIOR && $$ AVIATION...MICHELS SHORT TERM/MARINE...DLG LONG TERM...JLB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 130 PM EDT TUE OCT 23 2007 ...UPDATED FOR AVIATION... .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR RAIN SHOWERS THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC SHOWING A CLOSED LOW EMBEDDED IN THE BASE OF A LONG WAVE TROUGH OVER THE UPPER GREAT LAKES. THE TROUGH EXTENDS FROM A JAMES BAY SOUTHWEST ACROSS KANJ TO THE LOW OVER SOUTHWEST ARKANSAS. A BROAD RIDGE BLANKETS THE ROCKIES. A SHORTWAVE SLIDING DOWN THE LEE OF THE RIDGE IS OVER CENTRAL MANITOBA AND NORTHWEST ONTARIO. SURFACE ANALYSIS DEPICTS A LOW OVER SOUTHERN HUDSON BAY WITH A COLD FRONT DRAPED SOUTHWEST THROUGH THE MINNESOTA ARROWHEAD...THEN WEST THROUGH THE DAKOTAS. THE TROUGH OVER THE UPPER GREAT LAKES WILL MOVE TO SOUTHEAST MICHIGAN AND THE LOWER GREAT LAKES THIS AFTERNOON. THE ONTARIO SHORTWAVE WILL SAIL SOUTHEAST INTO THE THUNDER BAY AREA. THE COLD FRONT WILL SETTLE INTO THE WEST END OF LAKE SUPERIOR BY NOON AND INTO CENTRAL U.P. AND CENTRAL LAKE SUPERIOR BY LATE AFTERNOON. GUIDANCE SHOWING DEEP MOISTURE ACCOMPANYING THE LOW WILL SHIFT INTO CENTRAL ONTARIO BY NOON AND INTO LAKE SUPERIOR BY LATE AFTERNOON. THUS Q-VECTOR CONVERGENCE ACCOMPANYING THE SHORTWAVE AND ISENTROPIC ASCENT WITH THE FRONTAL SYSTEM WILL SQUEEZE SOME OF THE MOISTURE OUT OF THE AREA OF DEEP MOISTURE AND PRODUCE SCATTERED SHOWERS AREA THE U.P. THIS AFTERNOON AND NUMEROUS SHOWERS INTO WESTERN AND NORTHERN CENTRAL LAKE SUPERIOR. CLOUD COVER WILL INCREASE AS THE ISENTROPIC ASCENT INCREASES. RAIN IS ALREADY ACCOMPANYING THIS ACTIVITY OVER NORTHERN MINNESOTA AND WESTERN ONTARIO. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... VFR CONDITIONS ARE EXPECTED INTO THIS AFTERNOON TODAY BEFORE RAIN SHOWERS MOVE IN WITH THE CANADIAN FRONTAL PASSAGE. WHEN THE RAIN MOVES IN...MVFR CONDITIONS ARE POSSIBLE AT BOTH KCMX AND KSAW LATE THIS AFTERNOON INTO TONIGHT...ESPECIALLY ONCE THE WINDS SHIFT AROUND TO THE NORTHWEST. RAIN COULD MIX WITH OR CHANGE TO SNOW LATE TONIGHT BRINGING VSBYS DOWN TO MVFR AS WELL. WINDS WILL BE GUSTY TO 35 KNOTS OR GREATER LATE THIS AFTERNOON INTO THIS EVENING. GFS SHOWING SATURATED CONDITIONS AROUND 2.5K FEET AND LITTLE LIGHTER WINDS BY 18Z. GFS SHOWING 875MB TEMPERATURE AROUND -5C WITH SURFACE TEMPERATURES AROUND 4C THEREFORE LOOKS LIKE POSSIBILITY OF -RASN WILL CONTINUE UNTIL 18Z. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRESSURE DIVING TOWARD LAKE SUPERIOR FROM CENTRAL CANADA WILL BRING INCREASING W-SW WINDS INTO WESTERN LAKE SUPERIOR THIS MORNING BUT ARE EXPECTED TO REMAIN IN THE 25-30 KT RANGE. WINDS WILL THEN SHIFT W-NW BEHIND THE COLD FRONT IN THE AFTERNOON INTO TONIGHT. THE TIGHT GRADIENT COUPLED WITH STRONG COLD ADVECTION BEHIND THE FRONT WILL RESULT IN NW TO N GALES TO 35-40 KT ACROSS MOST OF LAKE SUPERIOR. WINDS WILL BEGIN TO SUBSIDE FROM THE WEST ON WED AS RIDGING BUILDS IN FROM THE NORTHERN PLAINS. SW WINDS WILL INCREASE TO 25 KT LATE WED NIGHT INTO THU AHEAD OF ANOTHER FRONTAL SYSTEM MOVING THROUGH SOUTH CENTRAL CANADA. WINDS WILL GENERALLY DIMINISH BLO 15 KT LATE THU NIGHT INTO FRI AS WEAK HIGH PRESSURE BUILDS OVER THE AREA. NORTH WINDS WILL PICK UP TO NEAR 30 KT AGAIN LATE FRI INTO SAT AS THE GRADIENT TIGHTENS BETWEEN A LOW PRESSURE CENTER MOVING INTO THE EASTERN GREAT LAKES AND STRENGTHENING HIGH PRESSURE OVER THE NORTHERN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... NEARSHORE AREAS OF LAKE SUPERIOR: GALE WARNING LSZ242 2 PM EDT TUE THROUGH MIDNIGHT TUE NIGHT. GALE WARNING LSZ243>246 2 PM EDT TUE THROUGH 6 AM EDT WED. GALE WARNING LSZ249>251 8 PM EDT TUE NIGHT THROUGH 8 AM EDT WED. OPEN WATERS OF LAKE SUPERIOR: GALE WARNING LSZ162 11 AM CDT TUE THROUGH 11 PM CDT TUE NIGHT. GALE WARNING LSZ263-264 11 AM EDT TUE THROUGH 6 AM EDT WED. GALE WARNING LSZ265 2 PM EDT TUE THROUGH 6 AM EDT WED. GALE WARNING LSZ266-267 2 PM EDT TUE THROUGH 8 AM EDT WED. && $$ SYNOPSIS/DISCUSSION...DLG AVIATION...DLG MARINE...VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1048 AM EDT TUE OCT 23 2007 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR RAIN SHOWERS THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC SHOWING A CLOSED LOW EMBEDDED IN THE BASE OF A LONG WAVE TROUGH OVER THE UPPER GREAT LAKES. THE TROUGH EXTENDS FROM A JAMES BAY SOUTHWEST ACROSS KANJ TO THE LOW OVER SOUTHWEST ARKANSAS. A BROAD RIDGE BLANKETS THE ROCKIES. A SHORTWAVE SLIDING DOWN THE LEE OF THE RIDGE IS OVER CENTRAL MANITOBA AND NORTHWEST ONTARIO. SURFACE ANALYSIS DEPICTS A LOW OVER SOUTHERN HUDSON BAY WITH A COLD FRONT DRAPED SOUTHWEST THROUGH THE MINNESOTA ARROWHEAD...THEN WEST THROUGH THE DAKOTAS. THE TROUGH OVER THE UPPER GREAT LAKES WILL MOVE TO SOUTHEAST MICHIGAN AND THE LOWER GREAT LAKES THIS AFTERNOON. THE ONTARIO SHORTWAVE WILL SAIL SOUTHEAST INTO THE THUNDER BAY AREA. THE COLD FRONT WILL SETTLE INTO THE WEST END OF LAKE SUPERIOR BY NOON AND INTO CENTRAL U.P. AND CENTRAL LAKE SUPERIOR BY LATE AFTERNOON. GUIDANCE SHOWING DEEP MOISTURE ACCOMPANYING THE LOW WILL SHIFT INTO CENTRAL ONTARIO BY NOON AND INTO LAKE SUPERIOR BY LATE AFTERNOON. THUS Q-VECTOR CONVERGENCE ACCOMPANYING THE SHORTWAVE AND ISENTROPIC ASCENT WITH THE FRONTAL SYSTEM WILL SQUEEZE SOME OF THE MOISTURE OUT OF THE AREA OF DEEP MOISTURE AND PRODUCE SCATTERED SHOWERS AREA THE U.P. THIS AFTERNOON AND NUMEROUS SHOWERS INTO WESTERN AND NORTHERN CENTRAL LAKE SUPERIOR. CLOUD COVER WILL INCREASE AS THE ISENTROPIC ASCENT INCREASES. RAIN IS ALREADY ACCOMPANYING THIS ACTIVITY OVER NORTHERN MINNESOTA AND WESTERN ONTARIO. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... VFR CONDITIONS ARE EXPECTED INTO MID AFTERNOON TODAY BEFORE RAIN SHOWERS MOVE IN WITH THE CANADIAN FRONTAL PASSAGE. WHEN THE RAIN MOVES IN...MVFR CONDITIONS ARE POSSIBLE AT BOTH KCMX AND KSAW LATE THIS AFTERNOON INTO TONIGHT...ESPECIALLY ONCE THE WINDS SHIFT AROUND TO THE NORTHWEST. RAIN COULD MIX WITH OR CHANGE TO SNOW LATE TONIGHT BRINGING VSBYS DOWN TO MVFR AS WELL. WINDS WILL BE GUSTY TO 35 KNOTS OR GREATER LATE THIS AFTERNOON INTO THIS EVENING. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRESSURE DIVING TOWARD LAKE SUPERIOR FROM CENTRAL CANADA WILL BRING INCREASING W-SW WINDS INTO WESTERN LAKE SUPERIOR THIS MORNING BUT ARE EXPECTED TO REMAIN IN THE 25-30 KT RANGE. WINDS WILL THEN SHIFT W-NW BEHIND THE COLD FRONT IN THE AFTERNOON INTO TONIGHT. THE TIGHT GRADIENT COUPLED WITH STRONG COLD ADVECTION BEHIND THE FRONT WILL RESULT IN NW TO N GALES TO 35-40 KT ACROSS MOST OF LAKE SUPERIOR. WINDS WILL BEGIN TO SUBSIDE FROM THE WEST ON WED AS RIDGING BUILDS IN FROM THE NORTHERN PLAINS. SW WINDS WILL INCREASE TO 25 KT LATE WED NIGHT INTO THU AHEAD OF ANOTHER FRONTAL SYSTEM MOVING THROUGH SOUTH CENTRAL CANADA. WINDS WILL GENERALLY DIMINISH BLO 15 KT LATE THU NIGHT INTO FRI AS WEAK HIGH PRESSURE BUILDS OVER THE AREA. NORTH WINDS WILL PICK UP TO NEAR 30 KT AGAIN LATE FRI INTO SAT AS THE GRADIENT TIGHTENS BETWEEN A LOW PRESSURE CENTER MOVING INTO THE EASTERN GREAT LAKES AND STRENGTHENING HIGH PRESSURE OVER THE NORTHERN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... NEARSHORE AREAS OF LAKE SUPERIOR: GALE WARNING LSZ242 2 PM EDT TUE THROUGH MIDNIGHT TUE NIGHT. GALE WARNING LSZ243>246 2 PM EDT TUE THROUGH 6 AM EDT WED. GALE WARNING LSZ249>251 8 PM EDT TUE NIGHT THROUGH 8 AM EDT WED. OPEN WATERS OF LAKE SUPERIOR: GALE WARNING LSZ162 11 AM CDT TUE THROUGH 11 PM CDT TUE NIGHT. GALE WARNING LSZ263-264 11 AM EDT TUE THROUGH 6 AM EDT WED. GALE WARNING LSZ265 2 PM EDT TUE THROUGH 6 AM EDT WED. GALE WARNING LSZ266-267 2 PM EDT TUE THROUGH 8 AM EDT WED. && $$ SYNOPSIS/DISCUSSION...JLA AVIATION...VOSS MARINE...VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 806 PM CDT TUE OCT 23 2007 .DISCUSSION...RATHER COOL SLUG OF LOW LEVEL AIR(850MB ZERO OVERHEAD ON EVENING RAOB) DESCENDING INTO THE CWFA AS COLD MID-UPPER LOW CENTER IN SERN AR MOVING ESEWD EARLY TONIGHT. HAVE DECIDED TO GO AHEAD WITH AN UPDATE TO FORECAST PACKAGE AS HOURLY TEMPS DROPPING OFF A LITTLE QUICKER AND HAVE LOWERED MINS A COUPLE OF DEGREES AT MOST LOCATIONS FOR EARLY WEDNESDAY. EXPECT STEADIER LIGHT RAINS ACROSS THE DELTA FROM 10 PM THRU DAYBREAK ON THE NW SIDE OF THE LOW. ALSO NUDGED HIGHS BACK A BIT FOR WEDNESDAY AS CORE OF COLD AIR HANGS TOUGH OVER ERN 2/3 MS. UPDATED GRIDS/WEB GRAPHICS HAVE BEEN SENT AND ZONES WILL BE COMING. REST OF FORECAST APPEARS ON TRACK AND PREVIOUS DISCUSSION FOLLOWS:/40/ SHORT TERM(TONIGHT THROUGH WEDNESDAY NIGHT)...CLOUDS...LIGHT DRIZZLE AND A CHANCE OF LIGHT RAIN WILL CONTINUE OVER THE CWA THROUGH WEDNESDAY NIGHT. LATEST SURFACE ANALYSIS HAS THE LOW OVER CENTRAL TENNESSEE WITH THE ASSOCIATED COLD FRONT MOVING INTO EASTERN ALABAMA. PLENTY OF CLOUD COVER WAS NOTED BEHIND THE FRONT WITH A RATHER SHARP EDGE OVER THE WESTERN ARKANSAS AND LOUISIANA STATE LINES. SATELLITE IMAGERY/RUC ANALYSIS SHOWS THE MID-UPPER CLOSED LOW OVER THE ARKANSAS/LOUISIANA STATE LINE. MODELS STILL DIVERGE ON THE TRACK OF THE LOW IN THE SHORT TERM BUT AGREE THAT THE LOW WILL MOVE EAST TONIGHT AND OVER MISSISSIPPI WEDNESDAY. BY WEDNESDAY EVENING THE GFS HAS THE LOW OVER SW ALABAMA...THE NAM HAS THE LOW OVER SW MISSISSIPPI AND THE ECMWF HAS THE LOW IN BETWEEN OVER SE MISSISSIPPI. FROM THERE THE MODELS BEGIN TO LIFT THE LOW NORTHWARD WEDNESDAY NIGHT. WATER VAPOR IMAGERY SHOWS PLENTY OF DRY AIR WRAPPING INTO THE LOW FROM THE SW LIMITING RAINFALL. THE BEST RAIN CHANCES ARE EXPECTED TO BE DIRECTLY BELOW AND NORTH OF THE LOW SO OUR FORECAST HINGES ON THE POSITION OF LOW. AS THE LOW DRIFTS OVER OUR CWA TONIGHT RAIN CHANCES WILL INCREASE FROM THE NORTHWEST. GREATEST RAINFALL CHANCES THROUGH THE PERIOD WILL BE CARRIED IN THE NORTH THROUGH THE PERIOD AND ENDING FROM THE SW WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN BELOW NORMAL. LATEST MAV GUIDANCE CAME IN A LITTLE TOO COOL AND BELOW LOWEST 00Z ENSEMBLE MEMBER SO HAVE GONE A COUPLE OF DEGREES WARMER TONIGHT. ALLOWING FOR A LITTLE SLOWER EASTWARD MOVEMENT WEDNESDAY OF THE UPPER LOW...HAVE TRIMMED SEVERAL DEGREES OFF HIGHS IN THE WEST. CURRENT THINKING IS THAT THE GFS BRINGS DRIER AIR INTO THE WEST A LITTLE TOO FAST ALLOWING FOR SOME SUN TO WARM OUR PARISHES. HELD MENTION OF RAIN IN OUR SW WEDNESDAY EVENING AS THE GFS BEGINS TO MOVE THE UPPER LOW OFF TO THE NE A LITTLE FAST. /22/ .LONG TERM...THURSDAY THROUGH NEXT TUESDAY...FOR THE MOST PART...I DIDN`T CHANGE MUCH FROM THE PREVIOUS LONG TERM FORECAST. MAV GUIDANCE CAME IN A GOOD BIT COOLER WITH TEMPERATURES...ESPECIALLY LOWS FRIDAY MORNING...ALONG WITH POPS AS IT`S ABOUT THE FASTEST AT DRYING US OUT RAINFALL-WISE THAN THE REST OF THE MODELS. WHILE I`M NOT BITING OFF ON THIS MUCH COOLER LOWER RAIN CHANCE SOLUTION HOOK LINE AND SINKER JUST YET...GIVEN THAT THERE IS DEFINITELY SOME COOLER DRIER AIR WORKING ITS WAY DOWN THE BACKSIDE OF THIS UPPER LOW AS IT SHIFTS EAST ACROSS THE FORECAST AREA...I`LL TREND BOTH HIGHS AND LOWS THURSDAY A COUPLE OF DEGREES COOLER THAN PREVIOUSLY FORECASTED...BUT WILL REMAIN ABOVE GUIDANCE FOR THE TIME BEING. THE SAME GOES FOR POPS...12Z MAV GUIDANCE CAME IN WITH MUCH LOWER POPS THAN PREVIOUSLY FORECASTED. THE REALLY GOOD DRIER AIR DOESN`T APPEAR TO ARRIVE UNTIL FRIDAY. MY FEELING IS THAT AS THIS UPPER LOW RETROGRADES TO THE NORTHEAST...THERE SHOULD STILL BE AT LEAST ENOUGH MOISTURE HANGING AROUND TO SQUEEZE OUT SOME LIGHT RAIN OR DRIZZLE OVER THE FORECAST AREA THURSDAY. ONCE AGAIN AS A RESULT...POPS LOOK TO BE LOWER THAN WHAT WAS PREVIOUSLY FORECASTED BUT HIGHER THAN WHAT GUIDANCE SUGGESTS IN MOST PLACES. AFTER THURSDAY...CONDITIONS WILL BEING TO IMPROVE AREA WIDE AS THE UPPER LOW MOVES FURTHER NORTHWARD UP AND OVER THE UPPER RIDGE TO THE EAST AND OUT OF THE REGION. THIS WILL ALLOW CLEARING...COOLER...AND DRIER CONDITIONS TO PREVAIL JUST IN TIME FOR THE WEEKEND. THE REMAINDER OF THE EXTENDED FORECAST REMAINS UNCHANGED AND PORTIONS OF PREVIOUS LONG TERM FORECAST DISCUSSION FOLLOWS BEGINNING WITH THE WEEKEND. /19/ FOR THE WEEKEND...OUR UPPER LOW LIFTS OUT OF THE AREA AND WE WILL SEE STRONG SFC HIGH PRESSURE BUILD INTO THE REGION. THE CENTER OF THE SFC HIGH WILL BE OVER THE MIDWEST WITH SFC PRESSURES OF 1030-1034MB. WE WILL SEE 1025-1028MB BUILD INTO OUR AREA AND THIS WILL SERVE TO BRING COOLER THAN AVG TEMPS FOR EARLY NEXT WEEK. OVERALL...GUID TEMPS LOOK GOOD FROM FRI-TUE...ESPECIALLY HIGHS. I DID MAKE A FEW TWEAKS TO LOW TEMPS DURING THOSE PERIODS TO GET SOME LOCATIONS AT OR JUST BELOW CLIMO LOWS. THE LARGEST CHANGE FROM GUID WAS ON TUE MORNING. GUID WAS ONLY OFFERING CLIMO LOWS IN THE UPPER 40S. THIS PERIOD LOOKS TO HAVE LIGHT WINDS AND GOOD RAD COOLING CONDITIONS WITH SFC DEWPTS IN THE UPPER 30S. I DID NOT GET TOO AGGRESSIVE AND ONLY CUT 2-4 DEGREES AREA WIDE. WE COULD SEE LOWER 40S TO UPPER 30S IF THIS AIRMASS STAYS THE COURSE LIKE THE MODELS SUGGEST./CME/ && .AVIATION...MVFR/IFR CEILINGS ALONG WITH LIGHT DRIZZLE/RAIN WILL CONTINUE THROUGH WEDNESDAY AS AN UPPER LEVEL LOW AND ABUNDANT LOW LEVEL MOISTURE REMAIN OVER THE FA. LIFR CEILINGS MAY DEVELOP IN THE NORTHWEST AFTER 08Z TONIGHT AND LAST THROUGH 15Z WED. THE UPPER LOW IS EXPECTED TO MOVE OVERHEAD WEDNESDAY. GUSTY NW SURFACE WINDS ARE EXPECTED TO DEVELOP ON THE W SIDE OF THE MID LEVEL LOW AS IT REACHES E CENTRAL MS AFTER 18Z./40/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 46 56 43 58 / 30 49 28 25 MERIDIAN 47 55 44 58 / 28 69 55 28 VICKSBURG 46 59 43 60 / 34 32 16 17 HATTIESBURG 47 56 46 60 / 18 39 24 13 NATCHEZ 46 60 42 61 / 16 20 15 12 GREENVILLE 46 59 43 58 / 62 42 17 27 GREENWOOD 46 55 42 57 / 58 58 32 30 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 300 PM CDT TUE OCT 23 2007 .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...CLOUDS...LIGHT DRIZZLE AND A CHANCE OF LIGHT RAIN WILL CONTINUE OVER THE CWA THROUGH WEDNESDAY NIGHT. LATEST SURFACE ANALYSIS HAS THE LOW OVER CENTRAL TENNESSEE WITH THE ASSOCIATED COLD FRONT MOVING INTO EASTERN ALABAMA. PLENTY OF CLOUD COVER WAS NOTED BEHIND THE FRONT WITH A RATHER SHARP EDGE OVER THE WESTERN ARKANSAS AND LOUISIANA STATE LINES. SATELLITE IMAGERY/RUC ANALYSIS SHOWS THE MID-UPPER CLOSED LOW OVER THE ARKANSAS/LOUISIANA STATE LINE. MODELS STILL DIVERGE ON THE TRACK OF THE LOW IN THE SHORT TERM BUT AGREE THAT THE LOW WILL MOVE EAST TONIGHT AND OVER MISSISSIPPI WEDNESDAY. BY WEDNESDAY EVENING THE GFS HAS THE LOW OVER SW ALABAMA...THE NAM HAS THE LOW OVER SW MISSISSIPPI AND THE ECMWF HAS THE LOW IN BETWEEN OVER SE MISSISSIPPI. FROM THERE THE MODELS BEGIN TO LIFT THE LOW NORTHWARD WEDNESDAY NIGHT. WATER VAPOR IMAGERY SHOWS PLENTY OF DRY AIR WRAPPING INTO THE LOW FROM THE SW LIMITING RAINFALL. THE BEST RAIN CHANCES ARE EXPECTED TO BE DIRECTLY BELOW AND NORTH OF THE LOW SO OUR FORECAST HINGES ON THE POSITION OF LOW. AS THE LOW DRIFTS OVER OUR CWA TONIGHT RAIN CHANCES WILL INCREASE FROM THE NORTHWEST. GREATEST RAINFALL CHANCES THROUGH THE PERIOD WILL BE CARRIED IN THE NORTH THROUGH THE PERIOD AND ENDING FROM THE SW WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN BELOW NORMAL. LATEST MAV GUIDANCE CAME IN A LITTLE TOO COOL AND BELOW LOWEST 00Z ENSEMBLE MEMBER SO HAVE GONE A COUPLE OF DEGREES WARMER TONIGHT. ALLOWING FOR A LITTLE SLOWER EASTWARD MOVEMENT WEDNESDAY OF THE UPPER LOW...HAVE TRIMMED SEVERAL DEGREES OFF HIGHS IN THE WEST. CURRENT THINKING IS THAT THE GFS BRINGS DRIER AIR INTO THE WEST A LITTLE TOO FAST ALLOWING FOR SOME SUN TO WARM OUR PARISHES. HELD MENTION OF RAIN IN OUR SW WEDNESDAY EVENING AS THE GFS BEGINS TO MOVE THE UPPER LOW OFF TO THE NE A LITTLE FAST. /22/ .LONG TERM...THURSDAY THROUGH NEXT TUESDAY...FOR THE MOST PART...I DIDN`T CHANGE MUCH FROM THE PREVIOUS LONG TERM FORECAST. MAV GUIDANCE CAME IN A GOOD BIT COOLER WITH TEMPERATURES...ESPECIALLY LOWS FRIDAY MORNING...ALONG WITH POPS AS IT`S ABOUT THE FASTEST AT DRYING US OUT RAINFALL-WISE THAN THE REST OF THE MODELS. WHILE I`M NOT BITING OFF ON THIS MUCH COOLER LOWER RAIN CHANCE SOLUTION HOOK LINE AND SINKER JUST YET...GIVEN THAT THERE IS DEFINITELY SOME COOLER DRIER AIR WORKING ITS WAY DOWN THE BACKSIDE OF THIS UPPER LOW AS IT SHIFTS EAST ACROSS THE FORECAST AREA...I`LL TREND BOTH HIGHS AND LOWS THURSDAY A COUPLE OF DEGREES COOLER THAN PREVIOUSLY FORECASTED...BUT WILL REMAIN ABOVE GUIDANCE FOR THE TIME BEING. THE SAME GOES FOR POPS...12Z MAV GUIDANCE CAME IN WITH MUCH LOWER POPS THAN PREVIOUSLY FORECASTED. THE REALLY GOOD DRIER AIR DOESN`T APPEAR TO ARRIVE UNTIL FRIDAY. MY FEELING IS THAT AS THIS UPPER LOW RETROGRADES TO THE NORTHEAST...THERE SHOULD STILL BE AT LEAST ENOUGH MOISTURE HANGING AROUND TO SQUEEZE OUT SOME LIGHT RAIN OR DRIZZLE OVER THE FORECAST AREA THURSDAY. ONCE AGAIN AS A RESULT...POPS LOOK TO BE LOWER THAN WHAT WAS PREVIOUSLY FORECASTED BUT HIGHER THAN WHAT GUIDANCE SUGGESTS IN MOST PLACES. AFTER THURSDAY...CONDITIONS WILL BEING TO IMPROVE AREA WIDE AS THE UPPER LOW MOVES FURTHER NORTHWARD UP AND OVER THE UPPER RIDGE TO THE EAST AND OUT OF THE REGION. THIS WILL ALLOW CLEARING...COOLER...AND DRIER CONDITIONS TO PREVAIL JUST IN TIME FOR THE WEEKEND. THE REMAINDER OF THE EXTENDED FORECAST REMAINS UNCHANGED AND THE PREVIOUS LONG TERM FORECAST DISCUSSION FOLLOWS BEGINNING WITH THE WEEKEND. /19/ FOR THE WEEKEND...OUR UPPER LOW LIFTS OUT OF THE AREA AND WE WILL SEE STRONG SFC HIGH PRESSURE BUILD INTO THE REGION. THE CENTER OF THE SFC HIGH WILL BE OVER THE MIDWEST WITH SFC PRESSURES OF 1030-1034MB. WE WILL SEE 1025-1028MB BUILD INTO OUR AREA AND THIS WILL SERVE TO BRING COOLER THAN AVG TEMPS FOR EARLY NEXT WEEK. OVERALL...GUID TEMPS LOOK GOOD FROM FRI-TUE...ESPECIALLY HIGHS. I DID MAKE A FEW TWEAKS TO LOW TEMPS DURING THOSE PERIODS TO GET SOME LOCATIONS AT OR JUST BELOW CLIMO LOWS. THE LARGEST CHANGE FROM GUID WAS ON TUE MORNING. GUID WAS ONLY OFFERING CLIMO LOWS IN THE UPPER 40S. THIS PERIOD LOOKS TO HAVE LIGHT WINDS AND GOOD RAD COOLING CONDITIONS WITH SFC DEWPTS IN THE UPPER 30S. I DID NOT GET TOO AGGRESSIVE AND ONLY CUT 2-4 DEGREES AREA WIDE. WE COULD SEE LOWER 40S TO UPPER 30S IF THIS AIRMASS STAYS THE COURSE LIKE THE MODELS SUGGEST. LASTLY...LOOKING A BIT BEYOND DAY 7...BOTH THE GFS/EURO ARE SHOWING A MORE POTENT TROUGH TO MOVE THROUGH AROUND THE 1ST OF NOV WHICH WOULD BRING MORE OF A CANADIAN AIRMASS. CURRENT INDICATIONS SUGGEST THE AREA MIGHT SEE OUR FIRST FREEZE...SOMETIME BETWEEN NOV 2-4. THIS WOULD BE A BIT EARLIER THAN NORMAL WHICH IS AROUND NOV 9. /CME/ && .AVIATION...MVFR/IFR CEILINGS ALONG WITH LIGHT DRIZZLE/RAIN WILL CONTINUE THROUGH WEDNESDAY AS AN UPPER LEVEL LOW AND ABUNDANT LOW LEVEL MOISTURE COMBINE. LIFR CEILINGS MAY DEVELOP IN THE NORTHWEST AFTER MIDNIGHT TONIGHT AND LAST THROUGH 15Z WED. THE UPPER LOW IS EXPECTED TO MOVE OVERHEAD WEDNESDAY. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 47 58 43 58 / 30 49 28 25 MERIDIAN 48 56 44 58 / 28 69 55 28 VICKSBURG 47 62 43 60 / 34 32 16 17 HATTIESBURG 48 57 46 60 / 18 39 24 13 NATCHEZ 46 61 42 61 / 16 20 15 12 GREENVILLE 48 59 43 58 / 62 42 17 27 GREENWOOD 48 56 42 57 / 58 58 32 30 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM/AVIATION:22 LONG TERM: 19/CME ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 1125 AM CDT TUE OCT 23 2007 .DISCUSSION...LATEST SURFACE ANALYSIS HAS THE LOW OVER CENTRAL TENNESSEE WITH THE FRONT TRAILING ACROSS ALABAMA. SATELLITE IMAGERY/RUC ANALYSIS HAS THE CLOSED LOW OVER SOUTHERN ARKANSAS. MOST OF THE SIGNIFICANT RAINFALL WILL OCCUR OVER EASTERN MISSISSIPPI THIS AFTERNOON AND OUR NORTHWEST MOST COUNTIES AS THE LOW DRIFTS CLOSER. MAINLY LIGHT DRIZZLE IS EXPECTED ELSEWHERE WITH EXTENSIVE CLOUD COVER. THE TIGHTENING PRESSURE GRADIENT MOVING INTO THE WESTERN PORTIONS OF OUR CWA WILL RESULT IN GUSTY WINDS THIS AFTERNOON. THIS WILL HELP HOLD TEMPERATURES DOWN CLOSE TO THEIR CURRENT READINGS IN THE 50S. UPDATES ARE POSTED TO REDUCE POPS AND ADD GUSTS THIS AFTERNOON. && .AVIATION...MVFR/IFR CONDITIONS IN CEILINGS AND LIGHT DRIZZLE/RAIN WILL CONTINUE THROUGH TODAY AS AN UPPER LEVEL LOW AND ABUNDANT LOW LEVEL MOISTURE COMBINE. GUSTY NORTHWEST WINDS WILL SPREAD ACROSS THE WESTERN HALF OF THE AREA THIS AFTERNOON. IFR CONDITIONS WILL PREVAIL AT ALL SITES AGAIN TONIGHT AS LOW CEILINGS AND DRIZZLE PERSISTS ACROSS THE AREA. && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 22 ms AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HASTINGS NE 201 PM CDT TUE OCT 23 2007 .DISCUSSION...DID AN UPDATE TO INCREASE HIGH TEMPERATURES FOR TODAY. && .PREV DISCUSSION... /ISSUED 1218 PM CDT TUE OCT 23 2007/ DISCUSSION...UPDATED THE FORECAST TO INCREASE WIND SPEEDS IN THE WEST. WIND GUSTS REALLY STARTING TO INCREASE IN THE LBF CWA AND COULD SEE SUSTAINED 20 TO 30 MPH. ALSO DECREASE SKY COVER TO ZERO FOR THE NEXT FEW PERIODS. AVIATION...18Z KGRI TAF. CLEAR SKY AND NO VISIBLITY RESTRICTIONS ARE EXPECTED THROUGH THE ENTIRE FORECAST. WIND WILL BE BREEZY THIS AFTERNOON FROM THE NORTHWEST...BUT THIS IS REALLY THE ONLY CONCERN AT THIS POINT. PREV DISCUSSION... /ISSUED 919 AM CDT TUE OCT 23 2007/ UPDATE...ZONE UPDATE SENT TO REMOVE MORNING FROST ADVISORY AND FREEZE WARNING. PREV DISCUSSION... /ISSUED 604 AM CDT TUE OCT 23 2007/ AVIATION...12Z TAF. VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DURATION OF THE TAF VALID PERIOD. LIGHT WEST WINDS EARLY THIS MORNING WILL INCREASE WITH DAY TIME HEATING AND BECOME MORE NORTHWESTERLY AND GUSTY BY EARLY AFTERNOON. WINDS WILL AGAIN DIE DOWN BY THIS EVENING AND AFTER A MOSTLY SUNNY DAY...KGRI COULD SEE A FEW SCATTERED CLOUDS DURING THE OVERNIGHT PERIOD. PREV DISCUSSION... /ISSUED 352 AM CDT TUE OCT 23 2007/ DISCUSSION...CLEAR SKIES...LIGHT WINDS...AND A VERY DRY AIRMASS IN PLACE HAVE LED TO THE COOLEST TEMPS OF THE SEASON ACROSS THE CWA THIS MORNING. TEMPS HAVE FALLEN INTO THE 30S AT ALL OBSERVING SITES...WITH DEWPOINTS IN THE LOWER 20S TO LOWER 30S. THUS THE GOING FREEZE WARNING AND FROST ADVISORY LOOK ON TRACK. LOOKING AT THE BIGGER PICTURE...WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS DATA SHOW AN ELONGATED TROUGH STRETCHING FROM A LOW OVER HUDSON BAY SOUTHWEST THROUGH TX...WITH AN EMBEDDED LOW HAVING CUT OFF OVER EASTERN TX/OK AS ADVERTISED. UPSTREAM AN AMPLIFYING UPPER RIDGE IS SPRAWLING OVER THE WESTERN CONUS...WITH A STRONG SURFACE HIGH CENTERED OVER THE GREAT BASIN. A FAIRLY QUIET PERIOD IS SHAPING UP ACROSS THE AREA FOR THE NEXT FEW DAYS. LIGHT WESTERLY WINDS ACROSS THE REGION THIS MORNING WILL TURN NORTHWESTERLY ON THE EASTERN PERIPHERY OF GREAT BASIN SURFACE HIGH AND BECOME BREEZY THIS AFTERNOON. THIS WILL INCREASE MIXING...WHICH COMBINED WITH WARMING H85 TEMPS AS THE EASTERN EDGE OF THE UPPER RIDGE NUDGES INTO THE REGION...WILL PUSH MAX TEMPS INTO THE UPPER 60S TO AROUND 70F. SHOULD SEE LOTS OF SUN TODAY AS WELL. MID CLOUDS CURRENTLY ACROSS THE WESTERN HIGH PLAINS HAVE BEEN STRUGGLING TO MAKE ANY EASTWARD PROGRESS. A FEW OF THESE MAY WORK ACROSS THE CWA LATER THIS MORNING INTO EARLY AFTERNOON...AND WILL SEE A FEW HIGH THIN CLOUDS SPILL SOUTH ACROSS THE REGION AS WELL BUT OVERALL NOT MUCH IN THE WAY OF CLOUD COVER. QUIET CONDITIONS CONTINUE TONIGHT WITH MILDER TEMPS ON TAP. MODELS HAVE COME INTO BETTER AGREEMENT WITH THEIR HANDLING OF THE SOUTHERN PLAINS CUTOFF LOW. THE GFS HAS TRENDED TOWARD THE ECMWF/UKMET/GEM SOLUTIONS...WHILE THE NAM REMAINS A WESTERN OUTLIER. THE MODEL CONSENSUS NOW PROGRESSES THE CUTOFF LOW INTO THE LOWER MS VALLEY BEFORE RETROGRADING IT AND PUSHING IT BACK NORTH THURSDAY AND FRIDAY...AND IT THEN GETS CAUGHT UP IN THE WESTERLIES AND PUSHED ACROSS THE EASTERN HALF OF THE COUNTRY THIS WEEKEND. HAVE THROWN OUT THE NAM SINCE IT APPEARS TO BE A STRONG OUTLIER. FOLLOWING THE OTHER MODEL SOLUTIONS...THE LOW LOOKS TO REMAIN SUFFICIENTLY FAR EAST TO KEEP ALL PRECIP EAST OF THE FORECAST AREA AND HAVE THUS LEFT THE DRY FORECAST IN PLACE. TURNING TO TEMPERATURES...MILD CONDITIONS CONTINUE ON WEDNESDAY BUT CENTRAL AND EASTERN AREAS OF THE CWA WILL SEE SOME SLIGHT COOLING AS WE PICK UP AN EASTERLY WIND COMPONENT BY AFTERNOON AS THE SURFACE HIGH CENTER SLIDES INTO THE UPPER MIDWEST. ABOVE AVERAGE TEMPS CONTINUE INTO THURSDAY BEFORE A SHORTWAVE TO THE NORTH SENDS A COLD FRONT THROUGH THE AREA ON FRIDAY...KNOCKING TEMPS BACK BELOW NORMAL. THE ATMOSPHERE CONTINUES TO LOOK MOISTURE STARVED WITH THE NEXT FRONT...AND HENCE PRECIP CHANCES APPEAR PRETTY BLEAK. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ HEINLEIN ne AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HASTINGS NE 1218 PM CDT TUE OCT 23 2007 .DISCUSSION...UPDATED THE FORECAST TO INCREASE WIND SPEEDS IN THE WEST. WIND GUSTS REALLY STARTING TO INCREASE IN THE LBF CWA AND COULD SEE SUSTAINED 20 TO 30 MPH. ALSO DECREASE SKY COVER TO ZERO FOR THE NEXT FEW PERIODS. && .AVIATION...18Z KGRI TAF. CLEAR SKY AND NO VISIBLITY RESTRICTIONS ARE EXPECTED THROUGH THE ENTIRE FORECAST. WIND WILL BE BREEZY THIS AFTERNOON FROM THE NORTHWEST...BUT THIS IS REALLY THE ONLY CONCERN AT THIS POINT. && .PREV DISCUSSION... /ISSUED 919 AM CDT TUE OCT 23 2007/ UPDATE...ZONE UPDATE SENT TO REMOVE MORNING FROST ADVISORY AND FREEZE WARNING. PREV DISCUSSION... /ISSUED 604 AM CDT TUE OCT 23 2007/ AVIATION...12Z TAF. VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DURATION OF THE TAF VALID PERIOD. LIGHT WEST WINDS EARLY THIS MORNING WILL INCREASE WITH DAY TIME HEATING AND BECOME MORE NORTHWESTERLY AND GUSTY BY EARLY AFTERNOON. WINDS WILL AGAIN DIE DOWN BY THIS EVENING AND AFTER A MOSTLY SUNNY DAY...KGRI COULD SEE A FEW SCATTERED CLOUDS DURING THE OVERNIGHT PERIOD. PREV DISCUSSION... /ISSUED 352 AM CDT TUE OCT 23 2007/ DISCUSSION...CLEAR SKIES...LIGHT WINDS...AND A VERY DRY AIRMASS IN PLACE HAVE LED TO THE COOLEST TEMPS OF THE SEASON ACROSS THE CWA THIS MORNING. TEMPS HAVE FALLEN INTO THE 30S AT ALL OBSERVING SITES...WITH DEWPOINTS IN THE LOWER 20S TO LOWER 30S. THUS THE GOING FREEZE WARNING AND FROST ADVISORY LOOK ON TRACK. LOOKING AT THE BIGGER PICTURE...WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS DATA SHOW AN ELONGATED TROUGH STRETCHING FROM A LOW OVER HUDSON BAY SOUTHWEST THROUGH TX...WITH AN EMBEDDED LOW HAVING CUT OFF OVER EASTERN TX/OK AS ADVERTISED. UPSTREAM AN AMPLIFYING UPPER RIDGE IS SPRAWLING OVER THE WESTERN CONUS...WITH A STRONG SURFACE HIGH CENTERED OVER THE GREAT BASIN. A FAIRLY QUIET PERIOD IS SHAPING UP ACROSS THE AREA FOR THE NEXT FEW DAYS. LIGHT WESTERLY WINDS ACROSS THE REGION THIS MORNING WILL TURN NORTHWESTERLY ON THE EASTERN PERIPHERY OF GREAT BASIN SURFACE HIGH AND BECOME BREEZY THIS AFTERNOON. THIS WILL INCREASE MIXING...WHICH COMBINED WITH WARMING H85 TEMPS AS THE EASTERN EDGE OF THE UPPER RIDGE NUDGES INTO THE REGION...WILL PUSH MAX TEMPS INTO THE UPPER 60S TO AROUND 70F. SHOULD SEE LOTS OF SUN TODAY AS WELL. MID CLOUDS CURRENTLY ACROSS THE WESTERN HIGH PLAINS HAVE BEEN STRUGGLING TO MAKE ANY EASTWARD PROGRESS. A FEW OF THESE MAY WORK ACROSS THE CWA LATER THIS MORNING INTO EARLY AFTERNOON...AND WILL SEE A FEW HIGH THIN CLOUDS SPILL SOUTH ACROSS THE REGION AS WELL BUT OVERALL NOT MUCH IN THE WAY OF CLOUD COVER. QUIET CONDITIONS CONTINUE TONIGHT WITH MILDER TEMPS ON TAP. MODELS HAVE COME INTO BETTER AGREEMENT WITH THEIR HANDLING OF THE SOUTHERN PLAINS CUTOFF LOW. THE GFS HAS TRENDED TOWARD THE ECMWF/UKMET/GEM SOLUTIONS...WHILE THE NAM REMAINS A WESTERN OUTLIER. THE MODEL CONSENSUS NOW PROGRESSES THE CUTOFF LOW INTO THE LOWER MS VALLEY BEFORE RETROGRADING IT AND PUSHING IT BACK NORTH THURSDAY AND FRIDAY...AND IT THEN GETS CAUGHT UP IN THE WESTERLIES AND PUSHED ACROSS THE EASTERN HALF OF THE COUNTRY THIS WEEKEND. HAVE THROWN OUT THE NAM SINCE IT APPEARS TO BE A STRONG OUTLIER. FOLLOWING THE OTHER MODEL SOLUTIONS...THE LOW LOOKS TO REMAIN SUFFICIENTLY FAR EAST TO KEEP ALL PRECIP EAST OF THE FORECAST AREA AND HAVE THUS LEFT THE DRY FORECAST IN PLACE. TURNING TO TEMPERATURES...MILD CONDITIONS CONTINUE ON WEDNESDAY BUT CENTRAL AND EASTERN AREAS OF THE CWA WILL SEE SOME SLIGHT COOLING AS WE PICK UP AN EASTERLY WIND COMPONENT BY AFTERNOON AS THE SURFACE HIGH CENTER SLIDES INTO THE UPPER MIDWEST. ABOVE AVERAGE TEMPS CONTINUE INTO THURSDAY BEFORE A SHORTWAVE TO THE NORTH SENDS A COLD FRONT THROUGH THE AREA ON FRIDAY...KNOCKING TEMPS BACK BELOW NORMAL. THE ATMOSPHERE CONTINUES TO LOOK MOISTURE STARVED WITH THE NEXT FRONT...AND HENCE PRECIP CHANCES APPEAR PRETTY BLEAK. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ HEINLEIN ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 919 AM CDT TUE OCT 23 2007 .UPDATE...ZONE UPDATE SENT TO REMOVE MORNING FROST ADVISORY AND FREEZE WARNING. && .PREV DISCUSSION... /ISSUED 604 AM CDT TUE OCT 23 2007/ AVIATION...12Z TAF. VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DURATION OF THE TAF VALID PERIOD. LIGHT WEST WINDS EARLY THIS MORNING WILL INCREASE WITH DAY TIME HEATING AND BECOME MORE NORTHWESTERLY AND GUSTY BY EARLY AFTERNOON. WINDS WILL AGAIN DIE DOWN BY THIS EVENING AND AFTER A MOSTLY SUNNY DAY...KGRI COULD SEE A FEW SCATTERED CLOUDS DURING THE OVERNIGHT PERIOD. PREV DISCUSSION... /ISSUED 352 AM CDT TUE OCT 23 2007/ DISCUSSION...CLEAR SKIES...LIGHT WINDS...AND A VERY DRY AIRMASS IN PLACE HAVE LED TO THE COOLEST TEMPS OF THE SEASON ACROSS THE CWA THIS MORNING. TEMPS HAVE FALLEN INTO THE 30S AT ALL OBSERVING SITES...WITH DEWPOINTS IN THE LOWER 20S TO LOWER 30S. THUS THE GOING FREEZE WARNING AND FROST ADVISORY LOOK ON TRACK. LOOKING AT THE BIGGER PICTURE...WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS DATA SHOW AN ELONGATED TROUGH STRETCHING FROM A LOW OVER HUDSON BAY SOUTHWEST THROUGH TX...WITH AN EMBEDDED LOW HAVING CUT OFF OVER EASTERN TX/OK AS ADVERTISED. UPSTREAM AN AMPLIFYING UPPER RIDGE IS SPRAWLING OVER THE WESTERN CONUS...WITH A STRONG SURFACE HIGH CENTERED OVER THE GREAT BASIN. A FAIRLY QUIET PERIOD IS SHAPING UP ACROSS THE AREA FOR THE NEXT FEW DAYS. LIGHT WESTERLY WINDS ACROSS THE REGION THIS MORNING WILL TURN NORTHWESTERLY ON THE EASTERN PERIPHERY OF GREAT BASIN SURFACE HIGH AND BECOME BREEZY THIS AFTERNOON. THIS WILL INCREASE MIXING...WHICH COMBINED WITH WARMING H85 TEMPS AS THE EASTERN EDGE OF THE UPPER RIDGE NUDGES INTO THE REGION...WILL PUSH MAX TEMPS INTO THE UPPER 60S TO AROUND 70F. SHOULD SEE LOTS OF SUN TODAY AS WELL. MID CLOUDS CURRENTLY ACROSS THE WESTERN HIGH PLAINS HAVE BEEN STRUGGLING TO MAKE ANY EASTWARD PROGRESS. A FEW OF THESE MAY WORK ACROSS THE CWA LATER THIS MORNING INTO EARLY AFTERNOON...AND WILL SEE A FEW HIGH THIN CLOUDS SPILL SOUTH ACROSS THE REGION AS WELL BUT OVERALL NOT MUCH IN THE WAY OF CLOUD COVER. QUIET CONDITIONS CONTINUE TONIGHT WITH MILDER TEMPS ON TAP. MODELS HAVE COME INTO BETTER AGREEMENT WITH THEIR HANDLING OF THE SOUTHERN PLAINS CUTOFF LOW. THE GFS HAS TRENDED TOWARD THE ECMWF/UKMET/GEM SOLUTIONS...WHILE THE NAM REMAINS A WESTERN OUTLIER. THE MODEL CONSENSUS NOW PROGRESSES THE CUTOFF LOW INTO THE LOWER MS VALLEY BEFORE RETROGRADING IT AND PUSHING IT BACK NORTH THURSDAY AND FRIDAY...AND IT THEN GETS CAUGHT UP IN THE WESTERLIES AND PUSHED ACROSS THE EASTERN HALF OF THE COUNTRY THIS WEEKEND. HAVE THROWN OUT THE NAM SINCE IT APPEARS TO BE A STRONG OUTLIER. FOLLOWING THE OTHER MODEL SOLUTIONS...THE LOW LOOKS TO REMAIN SUFFICIENTLY FAR EAST TO KEEP ALL PRECIP EAST OF THE FORECAST AREA AND HAVE THUS LEFT THE DRY FORECAST IN PLACE. TURNING TO TEMPERATURES...MILD CONDITIONS CONTINUE ON WEDNESDAY BUT CENTRAL AND EASTERN AREAS OF THE CWA WILL SEE SOME SLIGHT COOLING AS WE PICK UP AN EASTERLY WIND COMPONENT BY AFTERNOON AS THE SURFACE HIGH CENTER SLIDES INTO THE UPPER MIDWEST. ABOVE AVERAGE TEMPS CONTINUE INTO THURSDAY BEFORE A SHORTWAVE TO THE NORTH SENDS A COLD FRONT THROUGH THE AREA ON FRIDAY...KNOCKING TEMPS BACK BELOW NORMAL. THE ATMOSPHERE CONTINUES TO LOOK MOISTURE STARVED WITH THE NEXT FRONT...AND HENCE PRECIP CHANCES APPEAR PRETTY BLEAK. GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 604 AM CDT TUE OCT 23 2007 .AVIATION...12Z TAF. VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DURATION OF THE TAF VALID PERIOD. LIGHT WEST WINDS EARLY THIS MORNING WILL INCREASE WITH DAY TIME HEATING AND BECOME MORE NORTHWESTERLY AND GUSTY BY EARLY AFTERNOON. WINDS WILL AGAIN DIE DOWN BY THIS EVENING AND AFTER A MOSTLY SUNNY DAY...KGRI COULD SEE A FEW SCATTERED CLOUDS DURING THE OVERNIGHT PERIOD. && .PREV DISCUSSION... /ISSUED 352 AM CDT TUE OCT 23 2007/ DISCUSSION...CLEAR SKIES...LIGHT WINDS...AND A VERY DRY AIRMASS IN PLACE HAVE LED TO THE COOLEST TEMPS OF THE SEASON ACROSS THE CWA THIS MORNING. TEMPS HAVE FALLEN INTO THE 30S AT ALL OBSERVING SITES...WITH DEWPOINTS IN THE LOWER 20S TO LOWER 30S. THUS THE GOING FREEZE WARNING AND FROST ADVISORY LOOK ON TRACK. LOOKING AT THE BIGGER PICTURE...WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS DATA SHOW AN ELONGATED TROUGH STRETCHING FROM A LOW OVER HUDSON BAY SOUTHWEST THROUGH TX...WITH AN EMBEDDED LOW HAVING CUT OFF OVER EASTERN TX/OK AS ADVERTISED. UPSTREAM AN AMPLIFYING UPPER RIDGE IS SPRAWLING OVER THE WESTERN CONUS...WITH A STRONG SURFACE HIGH CENTERED OVER THE GREAT BASIN. A FAIRLY QUIET PERIOD IS SHAPING UP ACROSS THE AREA FOR THE NEXT FEW DAYS. LIGHT WESTERLY WINDS ACROSS THE REGION THIS MORNING WILL TURN NORTHWESTERLY ON THE EASTERN PERIPHERY OF GREAT BASIN SURFACE HIGH AND BECOME BREEZY THIS AFTERNOON. THIS WILL INCREASE MIXING...WHICH COMBINED WITH WARMING H85 TEMPS AS THE EASTERN EDGE OF THE UPPER RIDGE NUDGES INTO THE REGION...WILL PUSH MAX TEMPS INTO THE UPPER 60S TO AROUND 70F. SHOULD SEE LOTS OF SUN TODAY AS WELL. MID CLOUDS CURRENTLY ACROSS THE WESTERN HIGH PLAINS HAVE BEEN STRUGGLING TO MAKE ANY EASTWARD PROGRESS. A FEW OF THESE MAY WORK ACROSS THE CWA LATER THIS MORNING INTO EARLY AFTERNOON...AND WILL SEE A FEW HIGH THIN CLOUDS SPILL SOUTH ACROSS THE REGION AS WELL BUT OVERALL NOT MUCH IN THE WAY OF CLOUD COVER. QUIET CONDITIONS CONTINUE TONIGHT WITH MILDER TEMPS ON TAP. MODELS HAVE COME INTO BETTER AGREEMENT WITH THEIR HANDLING OF THE SOUTHERN PLAINS CUTOFF LOW. THE GFS HAS TRENDED TOWARD THE ECMWF/UKMET/GEM SOLUTIONS...WHILE THE NAM REMAINS A WESTERN OUTLIER. THE MODEL CONSENSUS NOW PROGRESSES THE CUTOFF LOW INTO THE LOWER MS VALLEY BEFORE RETROGRADING IT AND PUSHING IT BACK NORTH THURSDAY AND FRIDAY...AND IT THEN GETS CAUGHT UP IN THE WESTERLIES AND PUSHED ACROSS THE EASTERN HALF OF THE COUNTRY THIS WEEKEND. HAVE THROWN OUT THE NAM SINCE IT APPEARS TO BE A STRONG OUTLIER. FOLLOWING THE OTHER MODEL SOLUTIONS...THE LOW LOOKS TO REMAIN SUFFICIENTLY FAR EAST TO KEEP ALL PRECIP EAST OF THE FORECAST AREA AND HAVE THUS LEFT THE DRY FORECAST IN PLACE. TURNING TO TEMPERATURES...MILD CONDITIONS CONTINUE ON WEDNESDAY BUT CENTRAL AND EASTERN AREAS OF THE CWA WILL SEE SOME SLIGHT COOLING AS WE PICK UP AN EASTERLY WIND COMPONENT BY AFTERNOON AS THE SURFACE HIGH CENTER SLIDES INTO THE UPPER MIDWEST. ABOVE AVERAGE TEMPS CONTINUE INTO THURSDAY BEFORE A SHORTWAVE TO THE NORTH SENDS A COLD FRONT THROUGH THE AREA ON FRIDAY...KNOCKING TEMPS BACK BELOW NORMAL. THE ATMOSPHERE CONTINUES TO LOOK MOISTURE STARVED WITH THE NEXT FRONT...AND HENCE PRECIP CHANCES APPEAR PRETTY BLEAK. && .GID WATCHES/WARNINGS/ADVISORIES... NE...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041- 046>049-061>064-073>077-083>087. KS...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR KSZ005-006-017. FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ007-018-019. && $$ AVIATION...WESELY PREV DISCUSSION...KB ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 352 AM CDT TUE OCT 23 2007 .DISCUSSION...CLEAR SKIES...LIGHT WINDS...AND A VERY DRY AIRMASS IN PLACE HAVE LED TO THE COOLEST TEMPS OF THE SEASON ACROSS THE CWA THIS MORNING. TEMPS HAVE FALLEN INTO THE 30S AT ALL OBSERVING SITES...WITH DEWPOINTS IN THE LOWER 20S TO LOWER 30S. THUS THE GOING FREEZE WARNING AND FROST ADVISORY LOOK ON TRACK. LOOKING AT THE BIGGER PICTURE...WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS DATA SHOW AN ELONGATED TROUGH STRETCHING FROM A LOW OVER HUDSON BAY SOUTHWEST THROUGH TX...WITH AN EMBEDDED LOW HAVING CUT OFF OVER EASTERN TX/OK AS ADVERTISED. UPSTREAM AN AMPLIFYING UPPER RIDGE IS SPRAWLING OVER THE WESTERN CONUS...WITH A STRONG SURFACE HIGH CENTERED OVER THE GREAT BASIN. A FAIRLY QUIET PERIOD IS SHAPING UP ACROSS THE AREA FOR THE NEXT FEW DAYS. LIGHT WESTERLY WINDS ACROSS THE REGION THIS MORNING WILL TURN NORTHWESTERLY ON THE EASTERN PERIPHERY OF GREAT BASIN SURFACE HIGH AND BECOME BREEZY THIS AFTERNOON. THIS WILL INCREASE MIXING...WHICH COMBINED WITH WARMING H85 TEMPS AS THE EASTERN EDGE OF THE UPPER RIDGE NUDGES INTO THE REGION...WILL PUSH MAX TEMPS INTO THE UPPER 60S TO AROUND 70F. SHOULD SEE LOTS OF SUN TODAY AS WELL. MID CLOUDS CURRENTLY ACROSS THE WESTERN HIGH PLAINS HAVE BEEN STRUGGLING TO MAKE ANY EASTWARD PROGRESS. A FEW OF THESE MAY WORK ACROSS THE CWA LATER THIS MORNING INTO EARLY AFTERNOON...AND WILL SEE A FEW HIGH THIN CLOUDS SPILL SOUTH ACROSS THE REGION AS WELL BUT OVERALL NOT MUCH IN THE WAY OF CLOUD COVER. QUIET CONDITIONS CONTINUE TONIGHT WITH MILDER TEMPS ON TAP. MODELS HAVE COME INTO BETTER AGREEMENT WITH THEIR HANDLING OF THE SOUTHERN PLAINS CUTOFF LOW. THE GFS HAS TRENDED TOWARD THE ECMWF/UKMET/GEM SOLUTIONS...WHILE THE NAM REMAINS A WESTERN OUTLIER. THE MODEL CONSENSUS NOW PROGRESSES THE CUTOFF LOW INTO THE LOWER MS VALLEY BEFORE RETROGRADING IT AND PUSHING IT BACK NORTH THURSDAY AND FRIDAY...AND IT THEN GETS CAUGHT UP IN THE WESTERLIES AND PUSHED ACROSS THE EASTERN HALF OF THE COUNTRY THIS WEEKEND. HAVE THROWN OUT THE NAM SINCE IT APPEARS TO BE A STRONG OUTLIER. FOLLOWING THE OTHER MODEL SOLUTIONS...THE LOW LOOKS TO REMAIN SUFFICIENTLY FAR EAST TO KEEP ALL PRECIP EAST OF THE FORECAST AREA AND HAVE THUS LEFT THE DRY FORECAST IN PLACE. TURNING TO TEMPERATURES...MILD CONDITIONS CONTINUE ON WEDNESDAY BUT CENTRAL AND EASTERN AREAS OF THE CWA WILL SEE SOME SLIGHT COOLING AS WE PICK UP AN EASTERLY WIND COMPONENT BY AFTERNOON AS THE SURFACE HIGH CENTER SLIDES INTO THE UPPER MIDWEST. ABOVE AVERAGE TEMPS CONTINUE INTO THURSDAY BEFORE A SHORTWAVE TO THE NORTH SENDS A COLD FRONT THROUGH THE AREA ON FRIDAY...KNOCKING TEMPS BACK BELOW NORMAL. THE ATMOSPHERE CONTINUES TO LOOK MOISTURE STARVED WITH THE NEXT FRONT...AND HENCE PRECIP CHANCES APPEAR PRETTY BLEAK. && .AVIATION...06Z TAF. VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DURATION OF THE TAF VALID PERIOD. LIGHT WINDS EARLY THIS MORNING WILL INCREASE WITH DAY TIME HEATING AND BECOME MORE NORTHWESTERLY. WINDS WILL AGAIN DIE DOWN BY EVENING AND COULD SEE A FEW SCATTERED CLOUDS AFTER 11PM THIS EVENING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041- 046>049-061>064-073>077-083>087. KS...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR KSZ005-006-017. FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ007-018-019. && $$ KB/WESELY ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 800 PM EDT WED OCT 24 2007 .SYNOPSIS... A THREAT FOR SPOTTY SHOWERS WILL CONTINUE THROUGH TONIGHT AND THURSDAY ESPECIALLY FOR AREAS SOUTH OF DAYTON AND COLUMBUS...AS THE REGION REMAINS BETWEEN TWO DIFFERENT WEATHER SYSTEMS. A LARGE AND SLOW MOVING LOW PRESSURE CENTER WILL HEAD NORTHEAST THURSDAY NIGHT AND BRING A GREATER CHANCE OF RAIN FOR FRIDAY AND SATURDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... MID LEVEL TROUGH SLOW TO PULL OUT OF AREA THIS AFTERNOON...SO AM PLANNING ON KEEPING HIGH CHANCE OF SHRA INTO THE EVENING IN THE EASTERN FA. AXIS OF LOW LEVEL CONVERGENCE WILL BE SLOW TO PUSH TO THE SOUTHEAST...AS RUC HOLDS ON TO AREA OF CONVERGENCE ALONG THE OH RIVER INTO THE OVERNIGHT. WITH TIGHT GRADIENT BETWEEN THIS TROUGH AND THE UPPER LOW CURRENTLY OVER THE GULF COAST STATES...HAVE ALSO BUMPED UP WINDS FOR TONIGHT. LEFT A LINGERING SLIGHT CHANCE OF SHOWERS IN THE FAR SOUTH WITH WEAK LOW LEVEL CONVERGENCE AND AREA OF DEEPER MOISTURE. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... THE UPPER LEVEL LOW WILL CONTINUE TO ROTATE IN THE LOWER MS VALLEY...BUT WITH ESPECIALLY SOUTHERN FORECAST AREA VULNERABLE TO SCATTERED SHOWERS FROM THE OUTER BANDS OF THIS HIGH. SIGNIFICANT MODEL DIFFERENCES IN TIMING OF THE TRACK OF THE UPPER LOW...RESULTING IN GREAT DIFFERENCES IN PRECIPITATION CHANCES. HAVE GONE WITH AN SREF APPROACH. UPR LOW WILL LINGER OVER THE LOWER TN VALLEY BEFORE PULLING NW AND BECOMING A BROADER TROUGH AS IT LIFTS ALONG THE MID MS VALLEY. HAVE INCREASED PRECIPITATION CHANCES FOR THURSDAY NIGHT AS THE LOW BEGINS TO LIFT UP AND ESPECIALLY EASTERN FORECAST AREA TO RECEIVE DEEPER MOISTURE...WHILE WESTERN FORECAST AREA TO REMAIN IN THE DRIER AIR A LITTLE LONGER. SO HAVE KEPT WITH THE TREND OF LOWER CHANCES FOR RAINFALL IN THE WEST. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... SATURDAY...THE NAM...GFS AND ECMWF ARE IN DECENT AGREEMENT WITH A MID LEVEL LOW JUST WEST OF THE AREA. HIGH TEMPS WILL BE NEAR NORMAL...DEPENDING HIGHLY ON THE POSITION OF THE FEATURE. SCATTERED SHOWERS APPEAR REASONABLE INTO THE EVENING AS THE H5 LOW PUSHES OFF TO THE NE. SUNDAY THOUGH WEDNESDAY...THE MODEL CONSENSUS IS THAT HIGH PRESSURE BUILDS AND MOVES EAST OF THE REGION. GENERALLY...DRY CONDITIONS WILL PERSIST...WHILE HIGH AND LOW TEMPS WILL BE SLIGHTLY BELOW NORMAL. THE LOWS FOR BOTH SUNDAY AND MONDAY NIGHT WILL FALL WELL INTO THE 30S. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... STRONG UPPER LOW OVER THE SOUTHERN U.S. IS THE PRIMARY FOCUS FOR THIS TAF PERIOD. WIDESPREAD MOISTURE AND AREAS OF PRECIP HAVE BEEN ADVECTING AROUND THE EASTERN AND NORTHERN PERIPHERIES OF THE LOW TODAY. FORECASTING THIS MOISTURE PATTERN IS DIFFICULT SINCE THERE IS A GRADIENT BETWEEN MVFR/OCCLY IFR CIGS TO THE SOUTHEAST AND JUST HIGH CLOUDS TO THE NORTH. CURRENT INDICATIONS ARE THAT NERLY LOW LEVEL FLOW WILL CONTINUE TO PUSH THE LOW CLOUDS SOUTH OF THE OHIO RIVER OVERNIGHT...SO I HAVE KEPT VFR CONDITIONS FOR THE FIRST HALF OF THE TAF PERIOD. WILL MONITOR CLOUD TRENDS TO SEE IF LOW CIGS MIGRATE FURTHER NORTH THAN EXPECTED...ESPECIALLY AT KCVG. SECOND ITEM OF CONCERN IS TIGHT PRESSURE GRADIENT SETTING UP BETWEEN LOW PRESSURE OVER THE TENNESSEE VALLEY AND HIGH BUILDING INTO THE GREAT LAKES. THIS WILL KEEP WINDS HIGH OVERNIGHT INTO THURSDAY WITH GUSTS OCCLY 25KT OR EVEN HIGHER. FOR THURS...LOW STARTS TO MIGRATE NORTHWARD AND THE AREA OF MVFR CIGS AND SCATTERED SHOWERS OVER THE APPALACHIANS IS EXPECTED TO ADVECT NORTHWEST INTO ALL AREA TAF SITES LATE MORNING THROUGH THE AFTERNOON. BEST TIMING FOR PRECIP WILL BE ROUGHLY A 4 HOUR WINDOW IN THE EARLY TO MID AFTERNOON AS BAND OF H8 WARM AIR ADVECTION MOVES NORTH ACROSS THE AREA. MVFR CIGS WILL DEVELOP LATE MORNING AND WILL DROP THROUGH THE DAY. PRECIP SHOULD BE TOO SCATTERED TO MENTION ANYTHING MORE THAN A VCSH FOR NOW. OUTLOOK...MVFR OR IFR CIGS POSSIBLE THURSDAY NIGHT THROUGH FRIDAY AND SATURDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...HAWBLITZEL oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NASHVILLE TN 1120 AM CDT WED OCT 24 2007 .DISCUSSION...CLOSED UPPER LOW KEEPNG US SHROUDED IN CLOUDS THIS MORNING. RAINFALL HAS CERTAINLY SLACKENED OFF TODAY FROM WHAT WE SAW EARLIER THIS WEEK AND IT LOOKS LIKE AMOUNTS, OVERALL, WILL REMAIN RELATIVELY LIGHT THIS AFTERNOON. BOTH THE LATEST RUC AND WRF SHOW A LIKELIHOOD FOR AT LEAST SMALL MEASUREABLE AMOUNTS OF RAIN THIS AFTERNOON, AS CLOSED UPPER LOW SINKS SOUTHEASTWARD AND DRAGS BAND OF PRECIP SOUTHWARD ACROSS MOST OF THE MID STATE BY SUNSET. EVEN THOUGH IT LOOKS LIKE OUR MOST SOUTHERN COUNTIES COULD ESCAPE THE RAIN TODAY, DO NOT HAVE HIGH ENOUGH CONFIDENCE THAT IT WON`T RAIN AT LEAST A HUNDRETH BY SUNSET TO MESS WITH THE POPS. THUS, FOR NOW, WILL KEEP CURRENT ZFP INTACT. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 10 tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 1010 AM CDT TUE OCT 23 2007 .UPDATE... SURFACE FRONT RUNNING FROM CLAY-LAWRENCE COUNTIES WITH GOOD OVERRUNNING RAINS BEHIND IT. SOME AREAS OVER THE W-NW HAVE RECEIVED OVER 6 INCHES OF RAIN LAST 24 HOURS OR SO. REPORTS OF STREAM FLOODING OVER DECATUR CTY W TN. WILL ISSUE A SMALL STREAM ADVISORY FOR BENTON...STEWART...HUMPHRIES...MONTGOMERY AND HOUSTON COUTNIES AS MODERATE RAINS CONTINUE OVER THAT AREA. TEMPS BEHIND FRONT IN 50S. RUC HAS RAIN/FRONT GRADUALLY SHIFTING E DURING DAY. WILL UPDATE ZONES FOR TEMPS AND OTHER FINE TUNING. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MAG tn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 1222 PM CDT TUE OCT 23 2007 .AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH CLOUD COVER CONFINED TO ONLY A SMALL AMOUNT OF CIRRUS. THE ONLY AVIATION CONCERNS THROUGH 18Z WEDNESDAY WILL BE WIND-RELATED. NORTH TO NORTHWEST WINDS WILL REMAIN IN THE 15G25KT AREA THROUGH LATE AFTERNOON BEFORE DIMINISHING RAPIDLY AROUND 00Z. WINDS WILL REMAIN LIGHT OVERNIGHT BEFORE GRADUALLY VEERING TO THE NORTHEAST AFTER SUNRISE. JOHNSON && .PREV DISCUSSION... /ISSUED 626 AM CDT TUE OCT 23 2007/ AVIATION... DRY NW FLOW THRU A DEEP LAYER WILL CONTINUE TDA...WITH LITTLE OR NO CLOUD COVER EXPECTED. NWLY SFC WINDS WILL TREND TOWARD A MORE NLY DIRECTION THIS AFTN...WHILE INCREASING AND GUSTING TO AROUND 30KT TIL LATE AFTN. WINDS EXPECTED TO DIMINISH TO AROUND 10KT AROUND TIME OF SUNSET...REMAINING NWLY OVERNIGHT. NO STRATUS EXPECTED. VFR FCST CONTINUES NEXT 24 HOURS. COCKRELL PREV DISCUSSION... /ISSUED 327 AM CDT TUE OCT 23 2007/ DISCUSSION... WV IMAGERY AND RUC ANALYSIS INDICATE THE UPPER TROUGH IS BEGINNING TO TRANSITION INTO A CLOSED LOW WITH THE CENTER OF THE LOW IN EASTERN OKLAHOMA. APPEARS THE IS SLOWING DOWN AND DEEPENING...BUT GENERAL MOVEMENT IS STILL TO THE EAST SOUTHEAST. MODELS INITIALIZING WELL AND ALL INDICATE THAT THE LOW WILL MOVE NEAR SOUTHERN ARKANSAS BY 00Z THIS EVENING. GFS AND EURO HAVE SHOWN SOME CONSISTENCY OVER THE PAST 24 HOURS WITH THE PROGRESS OF THE LOW. THE NAM IS STILL THE OUTLIER KEEPING THE LOW SLIGHTLY FURTHER TO THE WEST...BUT IS TRENDING MUCH CLOSER TO THE GFS/EURO THAN BEFORE. WITH THAT IN MIND...TRENDED FORECAST CLOSER TO THE GFS/EURO OVER THE NEXT 7 DAYS. HIGH TEMPS TODAY SHOULD REBOUND BY 10 DEGREES OR SO REACHING THE UPPER 60S TO LOW 70S THIS AFTERNOON. MOSTLY CLEAR SKIES OVER THE NEXT FEW DAYS WILL ALLOW FOR PLENTY OF DAYTIME HEATING...BUT SFC WINDS WILL REMAIN OUT OF THE NORTH THROUGH THURSDAY MORNING. THE COOL AIR ADVECTION AND NORTHERLY FLOW ALOFT WILL HELP MODERATE TEMPS. APPEARS THURSDAY WILL BE THE WARMEST DAY OF THE WEEK AS THE WINDS START TO BACK DOWN AND VEER TO THE EAST. THE UPSLOPE COMPONENT WILL BE PRESENT...SO DID NOT GO AS WARM AS MEX...BUT HIGH TEMPS SHOULD STILL CREEP INTO THE 70S. AS FOR PRECIP CHANCES...DECIDED TO PULL ALL THE POPS BASED ON LATEST MODEL RUNS...OTHER THAN SOME SUB 10 POPS FOR THURSDAY NIGHT INTO FRIDAY MORNING. EVEN WITH THE FURTHER WEST NAM SOLUTION...THE PANHANDLES SHOULD REMAIN DRY. AS THE UPPER PATTERN TRANSITION FROM NORTHERLY FLOW ALOFT TO A BRIEF RIDGE ON SATURDAY...ANOTHER COLD FRONT AND SHOT OF COOLER AIR WILL MOVE INTO THE PANHANDLES. APPEARS TEMPS WILL ONLY FALL INTO THE LOWER 60S WITH THE FRONT...THEN REBOUND BY 5 DEGREES OR SO ON SUNDAY. OTHERWISE...STUCK CLOSE WITH MEX GUIDANCE. JJB && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 24/05 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 626 AM CDT TUE OCT 23 2007 .AVIATION... DRY NW FLOW THRU A DEEP LAYER WILL CONTINUE TDA...WITH LITTLE OR NO CLOUD COVER EXPECTED. NWLY SFC WINDS WILL TREND TOWARD A MORE NLY DIRECTION THIS AFTN...WHILE INCREASING AND GUSTING TO AROUND 30KT TIL LATE AFTN. WINDS EXPECTED TO DIMINISH TO AROUND 10KT AROUND TIME OF SUNSET...REMAINING NWLY OVERNIGHT. NO STRATUS EXPECTED. VFR FCST CONTINUES NEXT 24 HOURS. COCKRELL && .PREV DISCUSSION... /ISSUED 327 AM CDT TUE OCT 23 2007/ DISCUSSION... WV IMAGERY AND RUC ANALYSIS INDICATE THE UPPER TROUGH IS BEGINNING TO TRANSITION INTO A CLOSED LOW WITH THE CENTER OF THE LOW IN EASTERN OKLAHOMA. APPEARS THE IS SLOWING DOWN AND DEEPENING...BUT GENERAL MOVEMENT IS STILL TO THE EAST SOUTHEAST. MODELS INITIALIZING WELL AND ALL INDICATE THAT THE LOW WILL MOVE NEAR SOUTHERN ARKANSAS BY 00Z THIS EVENING. GFS AND EURO HAVE SHOWN SOME CONSISTENCY OVER THE PAST 24 HOURS WITH THE PROGRESS OF THE LOW. THE NAM IS STILL THE OUTLIER KEEPING THE LOW SLIGHTLY FURTHER TO THE WEST...BUT IS TRENDING MUCH CLOSER TO THE GFS/EURO THAN BEFORE. WITH THAT IN MIND...TRENDED FORECAST CLOSER TO THE GFS/EURO OVER THE NEXT 7 DAYS. HIGH TEMPS TODAY SHOULD REBOUND BY 10 DEGREES OR SO REACHING THE UPPER 60S TO LOW 70S THIS AFTERNOON. MOSTLY CLEAR SKIES OVER THE NEXT FEW DAYS WILL ALLOW FOR PLENTY OF DAYTIME HEATING...BUT SFC WINDS WILL REMAIN OUT OF THE NORTH THROUGH THURSDAY MORNING. THE COOL AIR ADVECTION AND NORTHERLY FLOW ALOFT WILL HELP MODERATE TEMPS. APPEARS THURSDAY WILL BE THE WARMEST DAY OF THE WEEK AS THE WINDS START TO BACK DOWN AND VEER TO THE EAST. THE UPSLOPE COMPONENT WILL BE PRESENT...SO DID NOT GO AS WARM AS MEX...BUT HIGH TEMPS SHOULD STILL CREEP INTO THE 70S. AS FOR PRECIP CHANCES...DECIDED TO PULL ALL THE POPS BASED ON LATEST MODEL RUNS...OTHER THAN SOME SUB 10 POPS FOR THURSDAY NIGHT INTO FRIDAY MORNING. EVEN WITH THE FURTHER WEST NAM SOLUTION...THE PANHANDLES SHOULD REMAIN DRY. AS THE UPPER PATTERN TRANSITION FROM NORTHERLY FLOW ALOFT TO A BRIEF RIDGE ON SATURDAY...ANOTHER COLD FRONT AND SHOT OF COOLER AIR WILL MOVE INTO THE PANHANDLES. APPEARS TEMPS WILL ONLY FALL INTO THE LOWER 60S WITH THE FRONT...THEN REBOUND BY 5 DEGREES OR SO ON SUNDAY. OTHERWISE...STUCK CLOSE WITH MEX GUIDANCE. JJB && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 67 43 65 44 69 / 0 0 0 0 5 BEAVER OK 70 44 68 41 72 / 0 0 0 0 10 BOISE CITY OK 67 40 70 41 72 / 0 0 0 0 0 BORGER TX 70 45 68 43 74 / 0 0 0 0 5 BOYS RANCH TX 71 43 70 41 73 / 0 0 0 0 5 CANYON TX 67 43 67 41 73 / 0 0 0 0 5 CLARENDON TX 68 44 66 42 68 / 0 0 0 0 5 DALHART TX 69 40 71 38 72 / 0 0 0 0 0 GUYMON OK 70 42 71 40 75 / 0 0 0 0 5 HEREFORD TX 69 43 67 40 74 / 0 0 0 0 5 LIPSCOMB TX 70 43 67 39 69 / 0 0 0 0 10 PAMPA TX 67 42 65 43 69 / 0 0 0 0 5 SHAMROCK TX 69 45 68 41 69 / 0 0 0 0 10 WELLINGTON TX 69 46 68 41 68 / 0 0 0 0 10 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR THE FOLLOWING ZONES: DALLAM...DEAF SMITH...HARTLEY...OLDHAM...POTTER... RANDALL. OK...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR THE FOLLOWING ZONES: CIMARRON. && $$ 03/14 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 327 AM CDT TUE OCT 23 2007 .DISCUSSION... WV IMAGERY AND RUC ANALYSIS INDICATE THE UPPER TROUGH IS BEGINNING TO TRANSITION INTO A CLOSED LOW WITH THE CENTER OF THE LOW IN EASTERN OKLAHOMA. APPEARS THE IS SLOWING DOWN AND DEEPENING...BUT GENERAL MOVEMENT IS STILL TO THE EAST SOUTHEAST. MODELS INITIALIZING WELL AND ALL INDICATE THAT THE LOW WILL MOVE NEAR SOUTHERN ARKANSAS BY 00Z THIS EVENING. GFS AND EURO HAVE SHOWN SOME CONSISTENCY OVER THE PAST 24 HOURS WITH THE PROGRESS OF THE LOW. THE NAM IS STILL THE OUTLIER KEEPING THE LOW SLIGHTLY FURTHER TO THE WEST...BUT IS TRENDING MUCH CLOSER TO THE GFS/EURO THAN BEFORE. WITH THAT IN MIND...TRENDED FORECAST CLOSER TO THE GFS/EURO OVER THE NEXT 7 DAYS. HIGH TEMPS TODAY SHOULD REBOUND BY 10 DEGREES OR SO REACHING THE UPPER 60S TO LOW 70S THIS AFTERNOON. MOSTLY CLEAR SKIES OVER THE NEXT FEW DAYS WILL ALLOW FOR PLENTY OF DAYTIME HEATING...BUT SFC WINDS WILL REMAIN OUT OF THE NORTH THROUGH THURSDAY MORNING. THE COOL AIR ADVECTION AND NORTHERLY FLOW ALOFT WILL HELP MODERATE TEMPS. APPEARS THURSDAY WILL BE THE WARMEST DAY OF THE WEEK AS THE WINDS START TO BACK DOWN AND VEER TO THE EAST. THE UPSLOPE COMPONENT WILL BE PRESENT...SO DID NOT GO AS WARM AS MEX...BUT HIGH TEMPS SHOULD STILL CREEP INTO THE 70S. AS FOR PRECIP CHANCES...DECIDED TO PULL ALL THE POPS BASED ON LATEST MODEL RUNS...OTHER THAN SOME SUB 10 POPS FOR THURSDAY NIGHT INTO FRIDAY MORNING. EVEN WITH THE FURTHER WEST NAM SOLUTION...THE PANHANDLES SHOULD REMAIN DRY. AS THE UPPER PATTERN TRANSITION FROM NORTHERLY FLOW ALOFT TO A BRIEF RIDGE ON SATURDAY...ANOTHER COLD FRONT AND SHOT OF COOLER AIR WILL MOVE INTO THE PANHANDLES. APPEARS TEMPS WILL ONLY FALL INTO THE LOWER 60S WITH THE FRONT...THEN REBOUND BY 5 DEGREES OR SO ON SUNDAY. OTHERWISE...STUCK CLOSE WITH MEX GUIDANCE. JJB && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 67 43 65 44 69 / 0 0 0 0 5 BEAVER OK 70 44 68 41 72 / 0 0 0 0 10 BOISE CITY OK 67 40 70 41 72 / 0 0 0 0 0 BORGER TX 70 45 68 43 74 / 0 0 0 0 5 BOYS RANCH TX 71 43 70 41 73 / 0 0 0 0 5 CANYON TX 67 43 67 41 73 / 0 0 0 0 5 CLARENDON TX 68 44 66 42 68 / 0 0 0 0 5 DALHART TX 69 40 71 38 72 / 0 0 0 0 0 GUYMON OK 70 42 71 40 75 / 0 0 0 0 5 HEREFORD TX 69 43 67 40 74 / 0 0 0 0 5 LIPSCOMB TX 70 43 67 39 69 / 0 0 0 0 10 PAMPA TX 67 42 65 43 69 / 0 0 0 0 5 SHAMROCK TX 69 45 68 41 69 / 0 0 0 0 10 WELLINGTON TX 69 46 68 41 68 / 0 0 0 0 10 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR THE FOLLOWING ZONES: DALLAM...DEAF SMITH...HARTLEY...OLDHAM...POTTER... RANDALL. OK...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR THE FOLLOWING ZONES: CIMARRON. && $$ 03/14 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 134 AM EDT WED OCT 24 2007 .SYNOPSIS... A FETCH OF ONSHORE MOISTURE INTERSECTING A STALLED COLD FRONT WILL ALLOW FOR GOOD CHANCES OF RAIN FOR THE AREA TONIGHT THROUGH FRIDAY. ANOTHER COLD FRONT WILL MOVE ACROSS THE REGION FRIDAY INTO SATURDAY WITH DRIER HIGH PRESSURE MOVING INTO THE AREA BY EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... FOR UPDATE LATER TONIGHT...HAVE ALREADY INC POP GRIDS TO REFLECT SHRAS MOVING FROM REIDSVILLE NC TO SAXE VA OVER THE NEXT FEW HOURS. ELSEWHERE...WILL PROB BE REDUCING POPS TO LOW LIKELIES...ESPECIALLY IN THE EXTREME WEST CONSIDERING NEWEST RUC AND RLX/LWX RECENT LOCAL WRF. AS IS TYPICAL IN THIS WAA REGIME...PRECIP HAVING PROBLEMS MAKING IT OVER THE WESTERN HIGHLANDS. IT WILL TAKE THE FRONT NOW IN WEST VA...TO REALLY GET PRECIP STARTED. HOWEVER...ITS PASSAGE MAY TAKE LONGER THAN MODELS INDICATE DUE TO STRONG SOUTHERLY FLOW EAST OF THE APPALACHIANS. WITH DISTURBANCES DUMPING INTO THE WESTERN EDGE OF THE TROF TO OUR WEST...THINKING UPPER PATTERN WILL BECOME MORE AMPLIFIED...LEADING TO LLVL WIND FIELD BACKING TO THE SSE AND SE. THIS MAY SERVE TO KEEP MOST OF THE SHOWERS FARTHER WEST THAN PREVIOUS MODEL RUNS INDICATED...PERHAPS EVEN INTO THE FIRST HALF OF WEDNESDAY. ALSO...DID TAKE DOWN SKY GRIDS...AS ANY CLOUDS THAT POPPED UP DUE TO HEATING WILL CRUMBLE...LEAVING SOME HOLES. LOW CLOUDS AND FOG SHOULD PERSIST TONIGHT AT HSP. WITH LESS CLDS IN THE SE PORTION OF CWA TONIGHT...LOWS THERE MAY BE A FEW DEGREES COLDER...ESPECIALLY AT MTV. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... THROUGH THIS PERIOD THE UPPER LOW TO OUR WEST WILL STALL OVER LOUISIANA AND RETROGRADE INTO ARKANSAS AND KANSAS. WHILE THIS IS HAPPENING...AN UPPER RIDGE WILL TRY TO MOVE ON SHORE FROM THE EAST...AND A SURFACE HIGH WILL SHIFT FROM THE GREAT LAKES REGION TO OVER NEW ENGLAND. WHAT WE HAVE SETTING UP FOR THE FORECAST AREA WILL BE A PROLONGED FETCH OF MOISTURE OUT OF BOTH THE EASTERN GULF OF MEXICO AND FROM OFF THE ATLANTIC ACROSS THE SOUTH CAROLINA COAST. THANKS TO THE DEVELOPING FLOW ALOFT...850 MB WINDS WILL TAKE ON MORE OF A SOUTHEASTERLY COMPONENT HELPING TO MAXIMIZE UPSLOPE CONDITIONS ALONG THE BLUE RIDGE...AND THANKS TO THE MOVEMENT OF THE SURFACE HIGH TO NEW ENGLAND AND STRONG LOW LEVEL WEDGE WILL FORM WITH INCREASING NORTHEASTERLY WINDS AT THE SURFACE. THE FORECAST WEDNESDAY NIGHT THROUGH THURSDAY WILL HAVE LIKELY TO CATEGORICAL CHANCES OF RAIN ALONG AND NEAR THE CREST OF THE BLUE RIDGE FROM ROUGHLY ROANOKE SOUTHWEST INTO NORTH CAROLINA WITH MAINLY 40 AND 50 PERCENT CHANCES ELSEWHERE. CLOUD COVER WILL BE ABUNDANT AND SO WILL AREAS OF FOG. DIURNAL TEMPERATURE CHANGES IN THE EAST WILL BE LIMITED TO 5 DEGREES AT BEST. THE BEST TEMPERATURE VARIATION IN THE FORECAST AREA WILL BE AROUND RICHLANDS VIRGINIA AND BLUEFIELD WEST VIRGINIA WHERE THE SOUTHEASTERLY FETCH AT 850 WILL HAVE A BIT OF A DOWNSLOPE COMPONENT TO IT. HERE A 10 DEGREE SWING WILL BE POSSIBLE BETWEEN LOW AND HIGH TEMPERATURES. FRIDAY THE WEDGE SHOULD BEGIN TO BREAK DOWN AS FIRST A WARM FRONT LIFTS NORTH ACROSS THE AREA...AND THEN AS THE UPPER LOW TO OUR WEST STARTS TO LIFT NORTHEAST...ITS ASSOCIATED COLD FRONT WILL BE APPROACHING THE AREA. PRECIPITATION CHANCES SHOULD REMAIN PRETTY GOOD THOUGH...IF NOT SLIGHTLY BETTER THAN THE DAY BEFORE. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MODEL GUIDANCE IS QUITE VARIABLE CONCERNING THE SPEED WHICH THE RETROGRADED UPPER LOW AND ITS ASSOCIATED COLD FRONT MAKE THEIR WAY BACK EAST ACROSS THE REGION OVER THE WEEKEND. FOR THE FORECAST HAVE MADE USE OF THE HPC GUIDANCE WHICH FOLLOWS BEST WITH THE ECMWF AND ENSEMBLE GFS MOS SOLUTIONS REGARDING BOTH PRECIPITATION TIMING AND CHANCES AND TEMPERATURES. SOME TWEAKS WERE MADE TO THIS GUIDANCE TO BETTER COLLABORATE WITH OFFICES THAT CHOSE OTHER SOLUTIONS. THE BEST CHANCE OF PRECIPITATION WILL BE FRIDAY NIGHT INTO SATURDAY WITH THE PASSAGE OF THE COLD FRONT THROUGH THE AREA. BEHIND THE FRONT POPS GRADUALLY TAPER OFF BUT NOT TO ZERO AS WE WILL STILL HAVE THE UPPER LOW PASSING NORTH OF THE AREA AND INCREASED NORTHWEST UPSLOPE FLOW TO CONTEND WITH MAINLY IN THE WEST. MONDAY NIGHT INTO TUESDAY HPC PLACES PARTS OF THE AREA IN A SLIGHT CHANCE FOR PRECIPITATION AS A LOW RIDES NORTHEAST ALONG A FRONT ALONG THE COAST AND HIGH PRESSURE SITS OVERHEAD. ANY PRECIPITATION WILL BE HARD PRESSED TO AMOUNT TO A WHOLE LOT GIVEN THIS SCENARIO. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... A MESOSCALE WAVE WORKING THROUGH SW CWA THROUGH THE OVERNIGHT HOURS WILL BRING SHOWERS TO SW VA/SE WV THROUGH SUNRISE. A NARROW LINE OF CONVECTION WORKING SLOWLY TO THE EAST AND THROUGH THE CAROLINAS MAY BRING A FEW TEMPO SHOWERS TO EASTERN SITES DURING THIS TIME. BEHIND THIS FEATURE...CEILINGS MAY IMPROVE SOME BUT CONFIDENCE NOT TO HIGH. WILL GO AHEAD AND KEEP VFR CONDITIONS OUTSIDE OF TEMPO SHOWERS IN THE EAST. ACROSS THE MOUNTAINS...RAIN CHANCES ARE HIGH WITH IFR/MVFR POSSIBLE WITH MOUNTAIN RIDGES BEING OBSCURED. VAD WINDS ALSO SHOWING 30+KTS SW FLOW WHILE SURFACE OBS ARE SOUTHERLY AT 6 KTS OR LESS. WIND SHEAR PROBLEMS ARE POSSIBLE THROUGH THE PERIOD. ONCE MESOSCALE WAVES MOVES THROUGH THE AREA THIS MORNING...WE SHOULD SEE A BREAK IN THE RAIN AND POSSIBLY THE CLOUDS. THIS WILL HELP PRODUCE INSTABILITY AND BRING CONVECTION INTO THE AREA DURING WEDNESDAY AFTERNOON...ESPECIALLY IN THE PIEDMONT. BY WEDNESDAY EVENING...STRONG FETCH OFF THE ATLANTIC AND UPSLOPE FLOW WILL BRING PERIODS OF RAIN TO THE AREA. DEFORMATION ZONE WILL ALSO SIT OVER THE REGION WHICH WILL KEEP RAIN AND LOW CLOUDS IN THE AREA FOR A LONGER PERIOD OF TIME. UPPER LEVEL SYSTEM APPROACHING FROM THE CENTRAL U.S. ON FRIDAY AND SATURDAY WILL KEEP THE AREA BELOW VFR THROUGH THE END OF THE WEEK. VFR CONDITIONS RETURN ON SUNDAY AS A COLD FRONT MOVES TO THE EAST COAST. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...KM SHORT TERM...DS LONG TERM...DS AVIATION...RCS va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 301 PM CDT TUE OCT 23 2007 .DISCUSSION...FCST FOCUS IN SHORT TERM IS GUSTY WIND POTENTIAL TONIGHT AND THEN ON HANDLING POPS WITH UPPER LOW THURSDAY NIGHT INTO SATURDAY. WATER VAPOR/RUC COMBO ANIMATION SHOWS SHORT WAVE RACING SEWD INTO LAKE SUPERIOR WITH HELP OF STG UPPER JET. H7 RH PROGS GIVE A GLANCING SHOT OF RH ASSOC WITH TAIL OF VORT INTO 00Z...THOUGH SATELLITE TRENDS TEND TO INDICATE THAT BULK OF MID LEVEL DECK AND ANY SPRINKLES WILL STAY NORTH OF CWA. RUC/NAM RH LOOKS A LITTLE BETTER THAN GFS IN THIS REGARD. WITH THE PASSAGE OF THE SFC TROUGH...NW WINDS WILL KICK IN. A 3 OR 4 MB FALL AHEAD OF TROUGH AND 3 MB RISE BEHIND...SO PERIOD OF GUSTY WINDS EXPECTED WITH TIGHTER GRADIENT INTO WED MRNG. IN FACT UPSTREAM WIND GUSTS IN MN RATHER FORMIDABLE. COLD AIR SC FIELD DRIVING SEWD IN WAKE OF VORT. WILL BUMP SKY GRIDS INTO PC RANGE TNGT INTO WED MRNG...WITH H8 COOL POOL IN PLACE FOR AT LEAS TTHE MRNG HRS ON WED. SFC HIGH SETTLES ACRS CWA FOR LATER WEDNESDAY AND RIGHT INTO THURSDAY. THE BIG ISSUE WILL BE HOW THE UPPER LOW BEHAVES FROM THURSDAY NIGHT INTO SATURDAY. A BIT CONCERNED ABOUT HOW QUICKLY THE GFS AND NAM WRAP PRECIP NW INTO THE CWA THU NGT GIVEN THE MODEL PLACEMENT OF UPPER LOW IN ARKANSAS AND OKLAHOMA VICINITY FRIDAY MORNING. SHOULD BE A GOOD AMOUNT OF DRY AIR IN PLACE TO HAVE TO WORK OVER AND THE NAM SOUNDINGS DO SHOW THE BETTER SATURATION COMES A BIT LATER THURSDAY NIGHT. UPSTREAM RIDGING IS STILL PROGGD TO BE ACRS THE CWA FRI MRNG. HOWEVER THE CONSISTENCY AND CONSENSUS OF BOTH THE GFS/NAM/ECMWF TO BRING PCPN NW INTO THE CWA THU NGT IS THERE AND WE ARE IN A COLLABORATIVE STATE WITH RESPECT TO THE GRIDS. MAY LOWER POPS A SMIDGE HOWEVER WITHIN THE RANGE OF TOLERANCE. CONFIDENCE INCREASES FOR FRIDAY INTO SATURDAY AS GFS AND ECMWF LIFT THE UPPER LOW NORTH AND THEN EAST...HOWEVER THE ECMWF TRACK IS CONSIDERABLY FURTHER SOUTH OF THE GFS AND REALLY ONLY GIVES US A GLANCING SHOT OF PRECIPITATION...WITH MUCH LIGHTER AMOUNTS THAN WHAT THE 00Z GFS WAS PAINTING. NOW THE 12Z GFS IS MUCH MORE PROGRESSIVE WITH LOW AND SHIFTS IT TO UR EAST BI FRI EVENING. THIS IS THE FIRST SOLUTION SHOWING THE QUICKER MOVEMENT AND WILL LEAN TOWARDS A LITTLE SLOWER SOLUTION PER THE ECMWF. SREF POPS SUGGEST BRINGING THE QPF IN A LITTLE SLOWER AND LINGERING A BIT LONGER WHICH SUPPORTS A SLOWER MOVEMENT OF THE UPPER SYSTEM. DRIER AIR WORKING IN FOR SUNDAY INTO TUESDAY WITH UPPER JET TO OUR NORTH AND OVERALL NO INFLUX OF MOISTURE. SFC HI WILL BE DOMINANT AND WILL GRADUALLY SHIFT EWAST AND SET UP A MILDER AND AT LEAST INITIALLY DRY SOUTHERLY FLOW. SFC LOW APPCHS BY TUE BUT STILL WELL WEST OF HERE AND 100-500 MEAN RH RATHER LOW. && 10 .AVIATION...A MID-LEVEL SHORTWAVE DROPPING SOUTHEAST THROUGH NORTHERN WISCONSIN IN THE NEXT 24 HOURS WILL DRAG A SURFACE FRONT THROUGH SOUTHERN WISCONSIN BETWEEN 00-06Z WED. NORTHWEST SURFACE WINDS BEHIND FRONT WILL BECOME MORE NORTHERLY BY SUNRISE WEDENSDAY. ONLY MID-LEVEL CLOUDS 8 TO 12 THSD FT AGL ARE EXPECTED ACROSS SOUTHERN WISCONSIN...SCT TO BKN. NO PRECIPITATION EXPECTED OVER SOUTEHRN WISCONSIN DUE TO DRYNESS OF AIR AND FACT THAT BEST ISENTROPIC LIFT TO REMAIN NORTH. DAYTIME HEATING WED WILL GENERATE SCT CUMULUS CLOUDS DUE TO MIXING. && .MARINE..NORTHWEST WINDS BEHIND SUFACE FRONT LATER TONIGHT WILL BECOME MORE NORTHERLY AND INCREASE IS SPEED. SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE TONIGHT INTO DAYTIME WEDNESDAY WITH WINDS GUSTING TO 25 TO 30 KNOTS. WAVES SHOULD THEN GET UP OVER 4 FEET AWAY FROM THE LAKE MICHIGAN SHORELINE. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 515 AM EDT THU OCT 25 2007 .DISCUSSION... WATER VAPOR LOOP AND RUC ANALYSIS SHOW A BROAD MID-UPR RIDGE STRETCHING FROM THE WRN GREAT LAKES THROUGH THE PLAINS TO THE SW STATES. THIS BROAD RIDGE IS FLANKED BY TROFS OVER WRN CANADA/PAC NW AND OVER ERN CANADA/NEW ENGLAND. ANOTHER FEATURE WHICH WILL AFFECT OUR WX FOR FRI INTO THE WEEKEND IS A CLOSED LOW OVER THE GULF COAST STATES. WITH RIDGE DOMINATING THIS MORNING OVER THE REGION SKIES HAVE BEEN MOSTLY CLEAR...EXCEPT FOR SOME LAKE EFFECT CLOUDS OVER FAR ERN UPR MI AND ALONG NRN LAKE MI COUNTIES. LACK OF CLOUDS AND LIGHT WINDS HAVE ALLOWED TEMPS TO FALL INTO THE 20S ACROSS MUCH OF INLAND FCST AREA...WITH LOWER 20S REALIZED OVER SOME OF THE WRN INTERIOR. WITH MID-LVL RIDGING STILL IN PLACE AND A WARM ADVECTION SRLY FLOW AHEAD OF THE NORTHERN PLAINS TROF...LOOK FOR 900 MB TEMPS OF 6-8C TO MIX TO THE SFC UNDER SUNNY SKIES...YIELDING HIGHS IN THE MID 50S ACROSS MUCH OF THE AREA WITH EVEN SOME UPPER 50S OVER THE WRN HALF. SFC RIDGE AXIS WILL LINGER OVER THE AREA TONIGHT AND MIN PRECIPITABLE WATER AXIS OF .25 INCH OVER THE AREA FOR MUCH OF THE NIGHT...RADIATIONAL COOLING WILL BE ENHANCED. WHILE THERE MAY BE SOME INCREASE IN CLOUDS FROM THE S LATE...STILL EXPECT ENOUGH RADIATIONAL COOLING FOR INLAND TEMPS TO LOWER TO THE UPPER 20S/LWR 30S WITH THE LOWEST READINGS OVER THE INTERIOR WEST...IN LINE WITH COOLER GFS MOS GUIDANCE. FRI...MODELS FINALLY COMING INTO BETTER AGREEMENT ON EVOLUTION/TRACK OF MID/UPPER LEVEL LOW AS IT LIFTS NNE AND ITS REMNANTS PHASE WITH NRN BRANCH SHORTWAVE OVER THE WEEKEND. MODEL CONSENSUS IS THAT THE LOW SHOULD DRIFT INTO SRN IL BY FRI EVENING AND THEN TRACK UP THE OHIO VALLEY EARLY SAT IN RESPONSE TO NRN BRANCH SHORTWAVE APPROACHING THE UPR GREAT LAKES AT THAT TIME. WITH DRY AIRMASS/RIDGING INITIALLY IN PLACE EARLY FRI FELT COMPELLED TO TRIM BACK SLIGHT CHC POPS FOR RAIN TO ONLY THE FAR SE PORTION OF THE CWA FOR FRI MORNING...THEN SPREAD SLIGHT CHC POPS INTO THE REST OF THE EAST FRI AFTERNOON AS BETTER MOISTURE AND WEAK Q-VECT CONV MOVE INTO THE AREA. AS DEEPENING SFC LOW LIFTS NORTH THROUGH LOWER MI FRI NIGHT...CYCLONIC NRLY FLOW BEHIND WILL INCREASE OVER UPR MI ESPECIALLY AFTER MIDNIGHT. SO HAVE KEPT IDEA OF INCREASING POPS ACROSS THE FCST AREA LATE FRI NIGHT WITH SOME LAKE ENHANCEMENT POSSIBLE AS 850 MB TEMPS LOWER TO 0 TO -3C TOWARD 12Z SAT. WITH 850 MB TEMPS CONTINUING TO FALL TO -6/-7C BY 00Z SUN ALONG WITH FREEZING LVLS...LOOK FOR SCATTERED LAKE EFFECT RAIN SHOWERS TO GRADUALLY MIX OR CHANGEOVER TO SNOW FROM THE WEST ON SAT. BETTER CHC OF SNOW SAT WILL BE OVER HIGHER TERRAIN AREAS OF WRN AND CENTRAL UPR MI AS FLOW BACKS NW THROUGH THE DAY. LONGER FETCH ACROSS ERN LAKE SUPERIOR MAY MODERATE LOW-LVLS AND KEEP PREDOMINANT PCPN-TYPE MORE RAIN THERE. GIVEN THAT THE MODELS SHOW THE FLOW BACKING THROUGH THE DAY AND BECOMING INCREASINGLY ANTICYCLONIC...WOULD NOT EXPECT A LOT OF ACCUMULATING RAIN OR SNOW AND DECIDED TO KEEP POPS AT 30/40 PCT ALONG THE NRN TIER COUNTIES. .AVIATION (FOR THE 06Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PD WITH RDG/LLVL DRY AIRMASS DOMINATING. FLOW TDAY WL SHIFT TO THE S WITH RDG AXIS TO THE E. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... PRESSURE FALLS AHEAD OF LOW PRESSURE SYSTEM SHIFTING ACROSS NORTHERN ONTARIO TODAY COULD LEAD TO LOCALIZED WINDS ABOVE 25 KNOTS OVER FAR NORTHERN SECTIONS OF THE OPEN LAKE. OTHERWISE...WINDS NEXT 24-36 HRS WILL STAY BELOW 25 KNOTS AS HIGH PRESSURE OVER REGION SLOWLY PRESSES EAST. NEXT OPPORTUNITY FOR STRONGER WINDS DEVELOPS LATE FRIDAY NIGHT INTO SATURDAY. LOW PRESSURE SYSTEM LIFTING NORTHEAST OUT OF THE MISSISSIPPI RIVER VALLEY COMBINES WITH STRONG HIGH PRESSURE TO THE WEST TO SET UP TIGHT PRESSURE GRADIENT. COLD AIR ADVECTION BECOMES SUBSTANTIAL TOO WHICH INCREASES LOWER LEVEL INSTABILITY ALLOWING STRONG WINDS ALOFT TO MIX TO THE SFC OR AT LEAST C-MAN AND SHIP LEVEL. GALES REMAIN POSSIBLE SATURDAY INTO SATURDAY EVENING...MOSTLY OVER CENTRAL AND EASTERN LAKE SUPERIOR. WINDS DIMINISH LATER SATURDAY NIGHT INTO SUNDAY AS A HIGH PRESSURE RIDGE SETTLES OVER THE REGION. WINDS MAY EXCEED 25 KNOTS AGAIN ON MON AHEAD OF STRONG COLD FRONT. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...VOSS AVIATION...KC MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 438 AM EDT THU OCT 25 2007 .SHORT TERM...TODAY HIGH PRESSURE CONTINUING TO BUILD ACROSS NORTHERN MICHIGAN EARLY THIS MORNING. THE RESULTANT WIND SHIFT TOWARD THE NORTHEAST LEADING TO BANDS OF LAKE INDUCED STRATO CU SHIFTING ACROSS THE EASTERN TIER OF COUNTIES...FROM HURON COUNTY DOWN THROUGH MACOMB COUNTY. THIS CLOUD DECK KEEPING TEMPS ELEVATED IN THESE LOCALES...WHILE TOWARD THE WEST CLR SKIES ALLOWING MOST LOCATIONS TO DRIFT GENERALLY INTO THE 35-40F RANGE. OVERALL COVERAGE OF FROST THIS MORNING REMAINS IN QUESTION AS A 4-8 KT NERLY GRADIENT PERSISTS. NONETHELESS...GIVEN CURRENT SATELLITE AND THERMAL TRENDS...SHOULD SEE ENOUGH LOCATIONS WITH FROST THIS MORNING TO WARRANT MAINTAINING THE ADVISORY FOR AREAS NORTH OF M-59 THROUGH 9 AM. THE EXCEPTIONS APPEAR TO BE ACROSS THE AFOREMENTIONED COUNTIES WHERE CLOUDS HAVE ENCROACHED...AND WILL THUS DROP THE ADVISORY HERE. FOR TODAY...SOUTHEAST LOWER MI WILL REMAIN BETWEEN HIGH PRESSURE SHIFTING INTO SOUTHERN ONTARIO/QUEBEC...AND LOW PRESSURE ORGANIZING OVER THE TENNESSEE VALLEY. ANY RESIDUAL LAKE EFFECT STRATUS WILL LIKELY MIX OUT BY MID/LATE MORNING...AS THE LAKE INDUCED TROUGH WEAKENS AND THE FLOW SHIFTS TOWARD THE EAST. OTHERWISE...A VERY DRY ATMOSPHERIC COLUMN AND GENERAL SUBSIDENCE WILL PROVIDE FOR FULL INSOLATION TODAY. DESPITE THIS...AIRMASS MODIFICATION WILL BE SLOW WITH THE PREDOMINANT GRADIENT MAINTAINING AN EASTERLY COMPONENT. THUS...WILL SEE HIGH TEMPERATURES ABOUT 3-6 DEGREES WARMER THAN YESTERDAY...WITH READINGS RIGHT AROUND NORMAL IN THE UPPER 50S. EASTERLY FLOW WILL KEEP AREAS CLOSER TO THE SHORELINES SLIGHTLY COOLER. && .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY MODELS SHOW THE UPPER LOW OVER THE GULF COAST STATES SLOWLY LIFTING NORTH UP THE MISSISSIPPI VALLEY TONIGHT. SOUTHEASTERLY WINDS ON THE EAST SIDE OF THIS SYSTEM WILL BRING MOISTURE FROM THE MID ATLANTIC REGION TO THE CENTRAL AND EASTERN GREAT LAKES. STRONG THETA-E ADVECTION IN THE 850-700MB LAYER BEGINS LATE THURSDAY EVENING AND CONTINUES THROUGH THE OVERNIGHT HOURS. LIGHT RAIN IS POSSIBLE AS THIS OCCURS BUT WILL HAVE TO OVERCOME THE DRY AIR THAT WAS IN PLACE EARLIER IN THE DAY. THE NAM SHOWS SLIGHTLY HIGHER INVERSION HEIGHTS TODAY AND ALSO SLIGHTLY MORE MOISTURE REMAINING BELOW 850MB...LIKELY HANDLING THE CONTRIBUTION OF NORTHEASTERLY FLOW OFF LAKE HURON A LITTLE BETTER THAN THE OTHER MODELS. WITH THIS IN MIND...BELIEVE SCATTERED LIGHT RAIN SHOWERS WILL MOVE INTO THE AREA AFTER MIDNIGHT AND HAVE SLIGHTLY RAISED POPS ACROSS OUR SOUTHEASTERN COUNTIES. THEN ON FRIDAY...THE UPPER LOW CONTINUES TO LIFT NORTH WITH VORTICITY ADVECTION LIFTING OVERHEAD DURING THE DAY AND A MID LEVEL DRY SLOT NOSING INTO SOUTHWEST LOWER MICHIGAN BY LATE AFTERNOON. INVERTED SURFACE TROUGH REALLY STARTS TO DEVELOP OVER LOWER MICHIGAN WITH STRONG MID LEVEL DEFORMATION SETTING UP OVER THE THUMB AND SOUTHERN LAKE HURON. MID LEVEL FRONTOGENESIS ALSO STRENGTHENS AS THE 850-700MB BAROCLINIC ZONE TIGHTENS AND HAVE INCREASED POPS TO LIKELY FOR THE EASTERN PORTION OF OUR CWA FOR FRIDAY AFTERNOON. THEN LARGE SCALE ASCENT INCREASES ON FRIDAY NIGHT AS THE UPPER LOW BEGINS TO PHASE WITH THE APPROACHING TROUGH AND THE SURFACE LOW DEEPENS AS IT TRACKS FROM NORTHERN INDIANA TO LAKE HURON. ALTHOUGH THERE IS A SLIGHT CONCERN THAT THIS UPPER LOW MAY TAKE A SLIGHTLY MORE WESTWARD TRACK...IT SEEMS WORTHWHILE OF AT LEAST A LIKELY POP IN SOME AREAS AND MAY NEED TO BE INCREASED AS CONFIDENCE IN TIMING AND LOCATION IMPROVE. GOOD COLD AIR ADVECTION KICKS IN BY SATURDAY AFTERNOON AS THE FIRST IN A SERIES OF SHORTWAVES MOVES THROUGH THE GREAT LAKES. TEMPERATURES WILL NOT RECOVER VERY MUCH ON SATURDAY AND HAVE LOWERED HIGHS A COUPLE DEGREES. HAVE ALSO TWEAKED TEMPS DOWN ANOTHER DEGREE FOR THE SATURDAY NIGHT THROUGH SUNDAY NIGHT TIME FRAME. IF HIGH PRESSURE IS ABLE TO BUILD OVER LOWER MICHIGAN ON SUNDAY NIGHT THEN A HARD FREEZE MAY BE POSSIBLE IN SOME LOCATIONS WITH WIDESPREAD TEMPS IN THE LOW 30S OUTSIDE OF THE DETROIT HEAT ISLAND. MODELS INDICATE AT LEAST THREE MORE SHORTWAVES WILL MOVE THROUGH THE FAST NORTHWEST FLOW ALOFT BETWEEN SUNDAY AND WEDNESDAY. HAVE MADE FEW CHANGES TO THE FORECAST IN THIS TIME FRAME AS THE FEATURES IN QUESTION ARE OVER THE NORTH ATLANTIC AND NOT BEING SAMPLED WELL YET BY RAOBS. MOISTURE WILL BE LIMITED WITH THESE WAVES AND CURRENT FORECAST HANDLES THAT WELL WITH JUST A LOW CHANCE OF SHOWERS ON MONDAY NIGHT. && .MARINE... STRENGTHENING HIGH PRESSURE WILL SLIDE BY TO THE NORTH TODAY...WHILE LOW PRESSURE APPROACHES FROM THE SOUTH. THIS WILL MAINTAIN A EASTERLY GRADIENT ACROSS THE AREA TODAY. THE STRONGEST PRESSURE GRADIENT WILL BE FOCUSED ACROSS THE SOUTHERN AREAS...LEADING TO INCREASING WINDS ACROSS WESTERN LAKE ERIE AND ST CLAIR TODAY. WAVES WILL ALSO INCREASE ALONG LAKE ERIE AS WINDS TRAVERSE THE LONG LAKE FETCH. THUS A SMALL CRAFT ADVISORY WILL BE IN EFFECT INTO TONIGHT FOR THESE LOCATIONS. MARGINAL SMALL CRAFT CONDITIONS WILL EXIST ALONG THE NEARSHORE WATERS OF LAKE HURON TODAY AND TONIGHT... BUT GIVEN THE EASTERLY FLOW...WILL CONTINUE TO SEE WAVES OVER 3 FEET. WINDS WILL VEER TOWARD THE SOUTHEAST AND SLACKEN ON FRIDAY AS A LOW PRESSURE SYSTEM APPROACHES THE AREA. WINDS WILL BEGIN TO STRENGHEN AGAIN BY SATURDAY AS THIS LOW PULLS NORTH AND WINDS SHIFT TOWARD THE WEST AND THEN NORTHWEST. THIS WILL BRING SMALL CRAFT CONDITIONS ONCE AGAIN FOR THE WEEKEND...WITH WINDS TO GALE FORCE A POSSIBILITY OVER THE OPEN WATERS OF LAKE HURON BY LATE SATURDAY INTO SATURDAY NIGHT. && .PREV DISCUSSION...ISSUED 103 AM EDT THU OCT 25 2007 / AVIATION... HIGH PRESSURE WILL TRAVERSE THE NORTHERN GREAT LAKES INTO ONTARIO BY AFTERNOON AS LOW PRESSURE DEEPENS OVER THE LOWER MISSISSIPPI VALLEY. THIS WILL HELP GENERATE THE MOST SIGNIFICANT AVIATION WEATHER WHICH WILL BE INCREASING WINDS FROM THE NORTHEAST...WITH GUSTS AROUND 20 KNOTS DURING THE AFTERNOON. THE LOW LEVEL WINDS ARE TURNING TO THE NORTHEAST ACROSS LAKE HURON. THIS WILL LIKELY BRING SOME LAKE EFFECT STRATO CU INTO SE MI DURING THE COURSE OF THE NIGHT. BASED ON THE 00Z NAM AND RUC SOUNDINGS...CLOUD BASES SHOULD REMAIN BETWEEN 3500 FT AND 4500 FT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ053-MIZ054-MIZ060-MIZ061-MIZ062- MIZ068-MIZ069...UNTIL 9 AM THURSDAY. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 11 AM FRIDAY. LAKE ST CLAIR... SMALL CRAFT ADVISORY...UNTIL 4 AM FRIDAY. MI WATERS OF LAKE ERIE... SMALL CRAFT ADVISORY...UNTIL 11 AM FRIDAY. && $$ SHORT TERM...MR LONG TERM....KRV MARINE.......MR AVIATION.....CONSIDINE 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 DETROIT/PONTIAC MI 103 AM EDT THU OCT 25 2007 .AVIATION... HIGH PRESSURE WILL TRAVERSE THE NORTHERN GREAT LAKES INTO ONTARIO BY AFTERNOON AS LOW PRESSURE DEEPENS OVER THE LOWER MISSISSIPPI VALLEY. THIS WILL HELP GENERATE THE MOST SIGNIFICANT AVIATION WEATHER WHICH WILL BE INCREASING WINDS FROM THE NORTHEAST...WITH GUSTS AROUND 20 KNOTS DURING THE AFTERNOON. THE LOW LEVEL WINDS ARE TURNING TO THE NORTHEAST ACROSS LAKE HURON. THIS WILL LIKELY BRING SOME LAKE EFFECT STRATO CU INTO SE MI DURING THE COURSE OF THE NIGHT. BASED ON THE 00Z NAM AND RUC SOUNDINGS...CLOUD BASES SHOULD REMAIN BETWEEN 3500 FT AND 4500 FT. && .PREV DISCUSSION...ISSUED 1019 PM EDT WED OCT 24 2007 UPDATE... A 1028 MB SURFACE HIGH NOW CENTERED OVER UPPER MI IS FORECAST TO BUILD EAST ACROSS NORTHERN LAKE HURON TONIGHT. THIS WILL CAUSE THE LOW LEVEL WIND FIELD TO VEER FROM NORTH TO NORTHEAST OVERNIGHT. THE LATEST IR IMAGE SHOWS QUITE A BIT OF LAKE EFFECT STRATO CU ACROSS LAKE HURON. EXPECT SOME OF THESE CLOUDS TO ADVECT INTO THE THUMB REGION DURING THE COURSE OF THE NIGHT AS THE WINDS VEER. MAY ALSO SEE SOME REDEVELOPMENT OF CLOUDS FURTHER INLAND AS MOISTURE FROM LAKE HURON GETS DUCTED UNDERNEATH THE STRONG INVERSION BASED AROUND 4500FT ON THE 00Z DTX SOUNDING. HAVE THEREFORE UPDATED THE GRIDS FOR A SLIGHT INCREASE IN CLOUD COVER ACROSS THE FORECAST AREA...ESPECIALLY IN THE THUMB REGION. BASED ON THE LATEST SATELLITE TRENDS...EXPECT THERE WILL BE ENOUGH CLEARING TONIGHT TO MAINTAIN THE CURRENT FORECAST MIN TEMPS. THUS THE FROST ADVISORY WILL REMAIN IN EFFECT. PREV DISCUSSION...ISSUED 631 PM EDT WED OCT 24 2007 SHORT TERM...THROUGH TONIGHT CLOUD DECK THAT DEVELOPED AS THE SUN TRIED TO COME OUT TODAY WILL QUICKLY DISSIPATE AROUND SUNRISE. PERSISTENT HIGH/MID CLOUDS FROM THE DEFORMATION ZONE ON THE NORTH END OF THE UPPER LOW OVER THE SOUTHERN U.S. HAVE STEADILY BEEN SHIFTING EAST AS FLOW ALOFT HAS TURNED TO THE NORTHWEST. SKIES ARE EXPECTED TO CLEAR OUT OVERNIGHT AS SURFACE HIGH PRESSURE AND ASSOCIATED SUBSIDENCE DOMINATE. CONCERN THEN TURNS TO FROST POTENTIAL WITH STRONG RADIATIONAL COOLING EXPECTED TO OCCUR. TEMPERATURES WILL BOTTOM OUT IN THE MID TO UPPER 30S OUTSIDE OF URBAN METRO DETROIT...WHICH IS JUST COOL ENOUGH TO PROMOTE FROST FORMATION. MODEL DATA INDICATES WINDS WILL SLACKEN OFF SOMEWHAT OVERNIGHT...EXCEPT OVER THE EXTREME SOUTHERN PORTION OF THE STATE WHERE THEY WILL START TO FEEL THE INFLUENCE FROM THE ADVANCING LOW PRESSURE SYSTEM CURRENTLY OVER MISSISSIPPI. WILL ISSUE A FROST ADVISORY FOR MOST OF THE FORECAST AREA...WITH THE EXCEPTION BEING OVER WASHTENAW...WAYNE...LENAWEE...AND MONROE COUNTIES. THINK WE WILL JUST SEE AREAS OF FROST THERE. LONG TERM...THURSDAY THROUGH WEDNESDAY CUTOFF UPPER LOW TO OUR SOUTH WILL RETROGRADE NORTHWEST TO MISSOURI LATE THURSDAY/THURSDAY NIGHT. THIS WILL BRING MOISTURE NORTH TOWARDS THE AREA...BUT WITH HIGH PRESSURE POISED OVER THE GREAT LAKES...DRY WEATHER SHOULD PREVAIL INTO THURSDAY EVENING...BEFORE LIGHT SHOWERS WORK INTO THE REGION OVERNIGHT. WILL DELAY THE NORTHWARD PROGRESSION OF PRECIPITATION AFTER MIDNIGHT THURSDAY NIGHT. THE BETTER CHANCE OF SHOWERS WILL HOLD OFF UNTIL FRIDAY/SATURDAY AS THIS UPPER LOW LIFTS NORTHEAST INTO THE REGION AS IT IS RE-ABSORBED BACK INTO THE NORTHERN STREAM FLOW IN ADVANCE OF A SHORTWAVE THAT DROPS INTO THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY. THE MODELS STILL VARY A FAIR AMOUNT ON THE EXACT EVOLUTION OF THIS PATTERN BUT THE GENERAL SCENARIO WILL BE FOR THE CWA TO BE ON THE WESTERN EDGE OF A SIGNIFICANT SHIELD OF RAINFALL THAT LIFTS NORTH ALONG THE APPALACHIAN MOUNTAINS INTO THE EASTERN GREAT LAKES/NEW ENGLAND ON FRIDAY/FRIDAY NIGHT. A DEFORMATION AXIS THEN CROSSES THE AREA WITH THE ACTUAL UPPER SYSTEM DURING THE DAY SATURDAY. ANOTHER SHOT OF CHILLY AIR MOVES INTO THE AREA IN BEHIND THIS LOW ON SATURDAY NIGHT/SUNDAY...SO EXPECT LOWS IN THE 30S IN MANY LOCATIONS BY SUNDAY MORNING...WITH AFTERNOON HIGHS ONLY IN THE UPPER 40S TO AROUND 50. ANOTHER SHORTWAVE BRUSHES THE AREA BY MONDAY NIGHT OR SO REINFORCING THE COOL AIRMASS OVER THE REGION...AND MAINTAIN LOWS GENERALLY IN THE 40S TO AROUND 40...WITH HIGHS IN THE 50S. MARINE... WINDS WILL CONTINUE TO GUST UP TO ABOUT 25 KNOTS OVER SAGINAW BAY AND THE LAKE HURON NEARSHORE WATERS THIS EVENING AS COLD AIR CONTINUES TO WORK INTO THE AREA BEHIND A COLD FRONT. WINDS AND WAVES OVER INNER SAGINAW BAY WILL DECREASE THROUGH THE EARLY EVENING...SUBSIDING TO BELOW SMALL CRAFT ADVISORY CRITERIA BY 8 PM. FOR THE REST OF THE LAKE HURON NEARSHORE WATERS...WINDS WILL DECREASE THIS EVENING...BUT PERSISTENT NORTH WINDS AND A LONG FETCH OVER THE WATER WILL CONTINUE TO ALLOW WAVES TO BUILD HIGHER THROUGH THE EVENING BEFORE THEY BEGIN TO SUBSIDE AFTER MIDNIGHT. WINDS AND WAVES WILL INCREASE OVER LAKE ERIE THURSDAY MORNING AS THE SURFACE PRESSURE GRADIENT TIGHTENS IN BETWEEN HIGH PRESSURE STRENGTHENING OVER THE NORTHERN GREAT LAKES AND LOW PRESSURE APPROACHING FROM THE SOUTH. A LONG EASTERLY FETCH OVER THE LAKE WILL ALSO CONTRIBUTE TO WAVE GENERATION. THIS WILL BRING SMALL CRAFT CONDITIONS TO WESTERN LAKE ERIE TOMORROW AND TOMORROW NIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060- MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070...UNTIL 9 AM THURSDAY. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 8 AM THURSDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE... SMALL CRAFT ADVISORY...FROM 8 AM THURSDAY TO 11 AM FRIDAY. && $$ AVIATION.....CONSIDINE UPDATE.......CONSIDINE SHORT TERM...HLO LONG TERM....DG MARINE.......HLO YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 720 AM EDT THU OCT 25 2007 UPDATED AVIATION SECTION FOR 12Z TAFS .DISCUSSION... WATER VAPOR LOOP AND RUC ANALYSIS SHOW A BROAD MID-UPR RIDGE STRETCHING FROM THE WRN GREAT LAKES THROUGH THE PLAINS TO THE SW STATES. THIS BROAD RIDGE IS FLANKED BY TROFS OVER WRN CANADA/PAC NW AND OVER ERN CANADA/NEW ENGLAND. ANOTHER FEATURE WHICH WILL AFFECT OUR WX FOR FRI INTO THE WEEKEND IS A CLOSED LOW OVER THE GULF COAST STATES. WITH RIDGE DOMINATING THIS MORNING OVER THE REGION SKIES HAVE BEEN MOSTLY CLEAR...EXCEPT FOR SOME LAKE EFFECT CLOUDS OVER FAR ERN UPR MI AND ALONG NRN LAKE MI COUNTIES. LACK OF CLOUDS AND LIGHT WINDS HAVE ALLOWED TEMPS TO FALL INTO THE 20S ACROSS MUCH OF INLAND FCST AREA...WITH LOWER 20S REALIZED OVER SOME OF THE WRN INTERIOR. WITH MID-LVL RIDGING STILL IN PLACE AND A WARM ADVECTION SRLY FLOW AHEAD OF THE NORTHERN PLAINS TROF...LOOK FOR 900 MB TEMPS OF 6-8C TO MIX TO THE SFC UNDER SUNNY SKIES...YIELDING HIGHS IN THE MID 50S ACROSS MUCH OF THE AREA WITH EVEN SOME UPPER 50S OVER THE WRN HALF. SFC RIDGE AXIS WILL LINGER OVER THE AREA TONIGHT AND MIN PRECIPITABLE WATER AXIS OF .25 INCH OVER THE AREA FOR MUCH OF THE NIGHT...RADIATIONAL COOLING WILL BE ENHANCED. WHILE THERE MAY BE SOME INCREASE IN CLOUDS FROM THE S LATE...STILL EXPECT ENOUGH RADIATIONAL COOLING FOR INLAND TEMPS TO LOWER TO THE UPPER 20S/LWR 30S WITH THE LOWEST READINGS OVER THE INTERIOR WEST...IN LINE WITH COOLER GFS MOS GUIDANCE. FRI...MODELS FINALLY COMING INTO BETTER AGREEMENT ON EVOLUTION/TRACK OF MID/UPPER LEVEL LOW AS IT LIFTS NNE AND ITS REMNANTS PHASE WITH NRN BRANCH SHORTWAVE OVER THE WEEKEND. MODEL CONSENSUS IS THAT THE LOW SHOULD DRIFT INTO SRN IL BY FRI EVENING AND THEN TRACK UP THE OHIO VALLEY EARLY SAT IN RESPONSE TO NRN BRANCH SHORTWAVE APPROACHING THE UPR GREAT LAKES AT THAT TIME. WITH DRY AIRMASS/RIDGING INITIALLY IN PLACE EARLY FRI FELT COMPELLED TO TRIM BACK SLIGHT CHC POPS FOR RAIN TO ONLY THE FAR SE PORTION OF THE CWA FOR FRI MORNING...THEN SPREAD SLIGHT CHC POPS INTO THE REST OF THE EAST FRI AFTERNOON AS BETTER MOISTURE AND WEAK Q-VECT CONV MOVE INTO THE AREA. AS DEEPENING SFC LOW LIFTS NORTH THROUGH LOWER MI FRI NIGHT...CYCLONIC NRLY FLOW BEHIND WILL INCREASE OVER UPR MI ESPECIALLY AFTER MIDNIGHT. SO HAVE KEPT IDEA OF INCREASING POPS ACROSS THE FCST AREA LATE FRI NIGHT WITH SOME LAKE ENHANCEMENT POSSIBLE AS 850 MB TEMPS LOWER TO 0 TO -3C TOWARD 12Z SAT. WITH 850 MB TEMPS CONTINUING TO FALL TO -6/-7C BY 00Z SUN ALONG WITH FREEZING LVLS...LOOK FOR SCATTERED LAKE EFFECT RAIN SHOWERS TO GRADUALLY MIX OR CHANGEOVER TO SNOW FROM THE WEST ON SAT. BETTER CHC OF SNOW SAT WILL BE OVER HIGHER TERRAIN AREAS OF WRN AND CENTRAL UPR MI AS FLOW BACKS NW THROUGH THE DAY. LONGER FETCH ACROSS ERN LAKE SUPERIOR MAY MODERATE LOW-LVLS AND KEEP PREDOMINANT PCPN-TYPE MORE RAIN THERE. GIVEN THAT THE MODELS SHOW THE FLOW BACKING THROUGH THE DAY AND BECOMING INCREASINGLY ANTICYCLONIC...WOULD NOT EXPECT A LOT OF ACCUMULATING RAIN OR SNOW AND DECIDED TO KEEP POPS AT 30/40 PCT ALONG THE NRN TIER COUNTIES. .AVIATION (FOR THE 12Z TAF ISSUANCE)... OVERALL...VFR CONDITIONS SHOULD DOMINATE THIS FCST PD WITH RDG/LLVL DRY AIRMASS OVER THE REGION. ONE EXCEPTION COULD BE AT KSAW. AS WINDS INCREASE FROM THE SOUTH...MVFR STRATOCU OVER LAKE MI COULD ADVECT INTO KSAW LATER THIS MORNING. DRY AIR MAY JUST ERODE THE CLOUD AS IT COMES TOWARD KSAW BUT DECIDED TO INCLUDE SCT-BKN MVFR CLOUDS THROUGH EARLY AFTN. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... PRESSURE FALLS AHEAD OF LOW PRESSURE SYSTEM SHIFTING ACROSS NORTHERN ONTARIO TODAY COULD LEAD TO LOCALIZED WINDS ABOVE 25 KNOTS OVER FAR NORTHERN SECTIONS OF THE OPEN LAKE. OTHERWISE...WINDS NEXT 24-36 HRS WILL STAY BELOW 25 KNOTS AS HIGH PRESSURE OVER REGION SLOWLY PRESSES EAST. NEXT OPPORTUNITY FOR STRONGER WINDS DEVELOPS LATE FRIDAY NIGHT INTO SATURDAY. LOW PRESSURE SYSTEM LIFTING NORTHEAST OUT OF THE MISSISSIPPI RIVER VALLEY COMBINES WITH STRONG HIGH PRESSURE TO THE WEST TO SET UP TIGHT PRESSURE GRADIENT. COLD AIR ADVECTION BECOMES SUBSTANTIAL TOO WHICH INCREASES LOWER LEVEL INSTABILITY ALLOWING STRONG WINDS ALOFT TO MIX TO THE SFC OR AT LEAST C-MAN AND SHIP LEVEL. GALES REMAIN POSSIBLE SATURDAY INTO SATURDAY EVENING...MOSTLY OVER CENTRAL AND EASTERN LAKE SUPERIOR. WINDS DIMINISH LATER SATURDAY NIGHT INTO SUNDAY AS A HIGH PRESSURE RIDGE SETTLES OVER THE REGION. WINDS MAY EXCEED 25 KNOTS AGAIN ON MON AHEAD OF STRONG COLD FRONT. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...VOSS AVIATION/MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 907 AM EDT THU OCT 25 2007 .SYNOPSIS... A COMPLEX FRONTAL SYSTEM WILL BRING UNSETTLED WEATHER TO THE EASTERN CAROLINAS THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY FOLLOWED BY HIGH PRESSURE SUNDAY THROUGH WEDNESDAY. && .NEAR TERM /THROUGH 6 PM/... WIDESPREAD RAIN ALONG THE COAST ASSOCIATED WITH SHORTWAVE MOVING NORTHWARD IN THE TROPICAL PLUME TO THE EAST OF THE UPPER LEVEL LOW CENTERED NEAR THE TENNESSEE-MISSISSIPPI BORDER. THIS WAVE HAS SHIFTED TO OUR NORTH WHICH IS REFLECTED IN THE MORE WIDESPREAD RAIN SEEN IN NORTHEAST NORTH CAROLINA. WATER VAPOR IMAGERY SHOWS TROPICAL CONNECTION CONTINUING OVER THE AREA WITH MODELS INDICATING THE DRIER AIR OVER THE WESTERN PART OF THE STATE REMAINING TO THE WEST. AS EARLY MORNING SHORTWAVE EXITS THE 11 UTC RUC INDICATES ANOTHER WAVE LOCATED OVER SOUTHERN FLORIDA WILL WORK ITS WAY NORTHWARD AND ENTER THE SOUTHERN PART OF THE CWA AROUND 21 UTC. AT THE SURFACE OCCLUDE FRONT IS LOCATED NEAR ILM AND IT EXTENDS SOUTHWARD INTO THE ATLANTIC. THE FRONTAL BOUNDARY IS EXPECTED TO REMAIN IN REGION AND AND RUC INDICATES THE FRONT PULLING BACK TO THE WEST THIS AFTERNOON PLACING A WEDGE OF WARM AIR FROM MURRELLS INLET THROUGH WHITEVILLE TO JACKSONVILLE. WITH THE INTERACTION OF THIS FRONT AND UPPER LEVEL ENERGY WILL SHOW HOURLY POPS SCATTERED UNTIL LATE AFTERNOON WITH INCREASING CHANCES AFTER 21 UTC. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... CONFIDENCE A LITTLE BETTER AS GUIDANCE BEGINS TO CONVERGE MORE ON A SINGLE SOLUTION. H5 CUT OFF LOW CENTERED OVER SOUTHERN ALABAMA LIFTS GENERALLY NNW THROUGH FRIDAY ALONG THE MISSISSIPPI RIVER VALLEY WITH A GOOD BIT OF WOBBLING ALONG THE WAY. ON SATURDAY LOW REJOINS THE WESTERLIES WHEN IT LIFTS FURTHER AND BECOMES ABSORBED WITHIN ADVANCING LONG WAVE TROUGH. AT THE SURFACE THIS WILL FINALLY LEAD TO A COLD FROPA ON SATURDAY AND MIN TEMPS SAT NIGHT IN THE 50S...FINALLY APPROACHING CLIMO. UNTIL THEN WARM AND MOIST SELY FLOW WILL CONTINUE TO BRING ABOVE CLIMO TEMPS AND UNSETTLED WEATHER TO THE EASTERN CAROLINAS. MODEL CROSS SECTIONS SHOW DEEP LAYER MOISTURE WILL CONTINUE THROUGH SATURDAY MORNING. WITH AMPLE MOISTURE AND PROXIMITY TO FRONT FEEL CONFIDENT IN CATEGORICAL POPS TONIGHT AND FRIDAY AND LIKELY POPS FRIDAY NIGHT...WITH PRECIP TAPERING OFF FROM WEST TO EAST ON SATURDAY. NOT TOO CONFIDENT ON DISTRIBUTION OF QPF THOUGH...ALTHOUGH IT IS LIKELY THAT MOST EVERYWHERE WILL MEASURE AT LEAST ONE HUNDREDTH OF AN INCH...THERE IS NO WAY TO TELL WHERE THE BULK OF IT WILL FALL. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ONCE COLD FRONT MOVES ACROSS AREA SUNDAY...COLDER AND DRIER AIR WILL MOVE IN FOR EARLY NEXT WEEK. OVERALL TRENDED POPS DECREASING AS DRIER AIR MOVES IN BEHIND FRONT ON SUNDAY INTO MONDAY. DRIEST DAYS LOOK TO BE SUNDAY AND TUESDAY. SOME CONTRAST BETWEEN 06Z RUN AND 12Z RUN OF GFS FOR FIRST HALF OF NEXT WEEK. 06Z RUN MOVED FRONT THROUGH AREA WITH COLD DRY AIR THROUGH MID WEEK AS SFC HIGH BUILDS IN FROM THE NORTH...BUT LATEST RUN SUGGESTS BUCKLING OF COLD FRONT AFTER IT PUSHES THROUGH ON SUNDAY PRODUCING A SURFACE TROUGH ALONG THE COAST INTO MID WEEK. ALSO MODELS IN FAIRLY GOOD AGREEMENT WITH MID LEVEL TROUGH AMPLIFYING THROUGH THE EARLY PART OF NEXT WEEK WHICH COULD ADD TO SOME UPPER LEVEL SUPPORT AND MOISTURE TO PROVIDE FOR SOME CLOUDS AND POSSIBLE SHOWERS THROUGH MID WEEK...BUT MAINLY ALONG THE COAST AND OFF SHORE IN COASTAL WATERS. THEREFORE KEPT SLIGHT CHC POPS INTO FIRST HALF OF NEXT WEEK...MAINLY FOCUSED ALONG THE COAST FOR NOW. GFS CUTS OFF ANOTHER LOW AT 500 MB OVER THE GULF COAST BY WEDNESDAY. TEMPS SHOULD DROP TO NEAR CLIMO AROUND 50 FOR MIN TEMPS AND 70 FOR MAX TEMPS THROUGH EARLY PART OF WEEK. IT WILL REMAIN BREEZY GOING INTO NEXT WEEK AS HIGH PRESSURE BUILDS IN INCREASING GRADIENT BETWEEN HIGH AND TROUGH ALONG THE SOUTHEAST COAST. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... COLD FRONT NEAR ILM MAY STILL MOVE SLIGHTLY SOUTH AND EAST EARLY TODAY...BUT OVERALL IT SHOULD REMAIN STATIONARY...THEN MOVE BACK TO THE WEST TONIGHT AS A WARM FRONT. THROUGH THIS AFTERNOON FLO/LBT SHOULD REMAIN NORTHWEST OF FRONT AND ILM/CRE/MYR SHOULD BE ALONG OR EAST OF FRONT. EAST OF THE FRONT TODAY VFR EXPECTED WITH TEMPO MVFR/SHOWERS/ISOLATED THUNDERSTORMS. WEST OF FRONT IFR THIS MORNING IMPROVING TO MVFR/VFR LATER THIS MORNING AND ISOLATED SHOWERS. THERE IS A GOOD CHANCE IFR CONDITIONS MAY CONTINUE INTO THIS AFTERNOON LBT/FLO. WIND DIRECTIONS WILL BE GENERALLY VARIABLE OR SOUTHEAST TO THE EAST OF THE FRONT...AND FROM THE EAST NORTHEAST TO THE WEST OF THE FRONT. AFTER 06Z RAINFALL INCREASES ACROSS THE TERMINALS... ESPECIALLY THE COASTAL TERMINALS. CHANCE THUNDERSTORMS FRIDAY SATURDAY AND MONDAY WITH TEMPO IFR CONDITIONS. && .MARINE... NEAR TERM /THROUGH 6 PM/... COLD FRONT HAS SHIFTED OFF THE COAST FROM NEAR CAPE FEAR SOUTHWARD TO THE EAST OF GEORGETOWN. AS MENTIONED IN THE NEAR TERM SECTION THE FRONT IS EXPECTED TO MOVE BACK THE WEST THIS AFTERNOON WITH THE APPROACHING SHORT WAVE ENERGY FROM THE SOUTH. SEAS CONTINUE TO RANGE OVER 6 FT ON DURATION OF SOUTHERN WINDS NORTH OF LITTLE RIVER. WILL CONTINUE SMALL CRAFT AS SEAS ARE EXPECTED TO SETTLE A BIT THIS AFTERNOON. WILL MAKE A FEW CHANGES TO WIND DIRECTIONS TO ACCOUNT FOR FRONTAL POSITION AND MOVEMENT. SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... BRISK SELY FLOW WILL CONTINUE SEAS OF 6 FT OR SO THROUGH THE FIRST PORTION OF THE SHORT TERM FOR OUR NORTHERN WATERS...SO WILL BE EXTENDING SCA FOR AMZ 250-252 OUT THROUGH FRIDAY. COLD FROPA SATURDAY WILL SHIFT WINDS OFFSHORE. WEAK OFFSHORE FLOW WILL LEAD TO RAPID DECLINE IN SEAS. MODEST COLD SURGE WILL LAG WELL BEHIND THE FRONT AND MAY NOT ARRIVE UNTIL LATE IN THE PERIOD...PERHAPS INCREASING SEAS BACK UP TO AROUND 4 OR 5 FT SATURDAY NIGHT. LONG TERM /SUNDAY THROUGH MONDAY/... THE COMBINATION OF THE COLD AIR ADVECTION AND A TIGHTER GRADIENT ON SUNDAY WILL PRODUCE INCREASING WINDS OUT OF THE NORTH WHICH IN TURN WILL PRODUCE AN INCREASE IN SEAS. WINDS WILL MAINTAIN A MORE ALONG SHORE N-NE FLOW UP TO 20 KTS OFF SHORE WHICH SHOULD KEEP SEAS IN THE 2 TO 4 FT RANGE NEAR SHORE AND 6 FT OR SLIGHTLY HIGHER OFF SHORE. A COASTAL TROUGH MAY DEVELOP IN THE EARLY PART OF WEEK WHICH SHOULD HELP TO MAINTAIN A TIGHTER GRADIENT FLOW THROUGH MID WEEK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR AMZ250-252. && $$ SYNOPSIS...REK NEAR TERM...HAWKINS SHORT TERM...REK AVIATION...MRR nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 228 PM MDT THU OCT 25 2007 .DISCUSSION...FORECAST PROBLEMS WILL BE MAX TEMPERATURES INTO EARLY NEXT WEEK AND IF ANY MEASURABLE PRECIPITATION WILL OCCUR FRIDAY NIGHT AND SATURDAY. SATELLITE SHOWING AN AMPLIFIED PATTERN CONTINUING FROM THE CENTRAL PORTION OF THE COUNTRY INTO THE WESTERN ATLANTIC. FLOW IS BECOMING MORE PROGRESSIVE FROM THE PACIFIC INTO THE WESTERN PORTION OF THE COUNTRY. UPPER LOW IN THE DEEP SOUTH IS BEGINNING TO MOVE NORTH AND WEST. RATHER STRONG AND POSITIVELY TILTED TROUGH IS PUSHING THROUGH CENTRAL CANADA AND THE PACIFIC NORTHWEST. LARGE HEIGHT FALLS ARE OCCURING IN THE PACIFIC NORTHWEST AS THE WESTERN RIDGE IS BEING FLATTENED AND PUSHED TO THE EAST. A LOT OF COLD AIR BEHIND SYSTEM TO THE NORTHWEST. AT JET LEVEL...NO SERIOUS INITIALIZATION PROBLEMS. AT MID LEVELS... MODELS INITIALIZED WELL WITH THE GFS DOING BETTER THAN THE UKMET/ECMWF IS SOME PLACES AND THE UKMET/ECMWF DOING BETTER THAN THE GFS IN OTHER PLACES. AT LOW LEVELS...THE NAM WAS DOING A LITTLE BETTER THAN THE UKMET. TEMPERATURES HAD THE WORST PROBLEMS. TO THE SOUTH THE UKMET/ECMWF WERE THE BEST. HOWEVER AS MOVED WELL TO THE NORTH AND NORTHWEST OF THE AREA...THE MODELS BECAME TOO COOL JUST AHEAD OF THE FRONT WITH THE GFS DOING THE BEST. BEHIND THE FRONT... THE GFS/UKMET/ECMWF WERE DOING WELL. WILL BE USING A BLEND OF THE MODEL OUTPUT SINCE THERE WAS TOO MUCH DIFFERENCE BETWEEN THEM. TONIGHT/FRIDAY...TEMPERATURES WILL DEPEND ON THE FRONTAL TIMING. BY 12Z...THE MODELS IN GENERAL ARE IN THE NORTHWEST THIRD TO HALF OF THE FORECAST AREA. THE WINDS LOOK PRETTY LIGHT ACROSS THE ENTIRE AREA AROUND 12Z WHICH SHOULD ALLOW THE TEMPERATURES TO DROP PRETTY GOOD. SO SOME LOCATIONS COULD START OUT FROM A CHILLY TEMPERATURE. THE UKMET IS THE SLOWEST WITH THE GFS SLIGHTLY FASTER. THE NAM AND ECMWF ARE THE FASTEST WITH THE RUC13 JUST BEHIND THEM. THE SREF IS SLIGHTLY FASTER THAN THE NAM AND ECMWF. SO HAVING A FRONT IN THE NORTHWEST HALF TO START THE DAY IS NOT UNREASONABLE. FRONT LOOKS TO BE THROUGH THE FORECAST AREA NOT TOO LONG AFTER 18Z. CLOUD COVER STARTS INCREASING FROM THE NORTHWEST DURING THE MORNING AND OVERSPREADS THE AREA IN THE AFTERNOON. SO THE NORTHWEST HALF OR SO WILL SEE THE LEAST AMOUNT OF SUN. WILL TEND TO GO NEAR TO SLIGHTLY COOLER THAN GUIDANCE FOR MINS. WILL ALSO GO A LITTLE COOLER THAN GUIDANCE AS WELL FOR THE MAXES. FRIDAY NIGHT/SATURDAY...MODEL SOUNDINGS SHOWING THE SAME PICTURE AS YESTERDAY IN REGARDS TO THE MOISTURE PROFILE BEHIND THE FRONT. THE SOUNDINGS DO SHOW THAT THAT ICE IS STILL NOT IN THE COLUMN BUT IT IS GETTING CLOSER. THE LIFT IS VERY WEAK ALOFT UNTIL THE JET MOVES THROUGH DURING THE DAY ON SATURDAY. STILL NOT OVERLY IMPRESSED WITH THE POSSIBILITY OF ANY MEASURABLE PRECIPITATION. OVERNIGHT SHIFT CUT DOWN THE AREA OF SPRINKLES AND FLURRIES. AT THIS TIME...I HAVE TAKEN IT COMPLETELY OUT. IN ADDITION TO COLD HIGH PRESSURE AND UPSLOPE WINDS DURING THE DAY... IT LOOKS LIKE CLOUDS WILL HANG AROUND FOR A MAJORITY OF THE DAY ACCORDING TO THE SOUNDINGS. WILL CONTINUE TO KEEP IT COOL AND NEAR TO SLIGHTLY BELOW GUIDANCE. SATURDAY NIGHT/SUNDAY...CLOUD COVER LOOKS TO DECREASE RAPIDLY AFTER 06Z. HOWEVER...BY THAT TIME...SOME RETURN FLOW STARTS BUT WINDS REMAIN LIGHT...ESPECIALLY IN THE EAST. WILL GO NEAR TO SLIGHTLY BELOW GUIDANCE FOR MINS. SURFACE HIGH PRESSURE MOVES OFF TO THE EAST AND START GETTING RETURN FLOW ON SUNDAY. UPPER RIDGE BEGINS BUILDING IN AND MODELS INDICATE DIFFERENT AMPLITUDE AND POSITION OF THE RIDGE. THE ECMWF IS BROADER/STRONGER AND MORE OF A WEST NORTHEST TO NORTHWEST FLOW ALOFT. THE GFS HAS MORE AMPLITUDE TO THE RIDGE WITH THE RIDGE FURTHER TO THE WEST...AND LEAVES THE AREA MORE IN A NORTH NORTHWEST TO NORTHWEST FLOW ALOFT. CONSEQUENTLY THE ECMWF IS WARMER AT THE SURFACE THAN THE GFS. WILL HAVE PLENTY OF SUN WHICH MAY COUNTERACT THE RECYCLED COOL AIR AT THE SURFACE. WILL GO NEAR TO SLIGHTLY BELOW GUIDANCE. SUNDAY NIGHT INTO MONDAY NIGHT...AGAIN SAME ISSUE WITH THE RIDGE POSITION AND STRENGTH OCCUR ON MONDAY BUT ARE NOT AS BAD. THE ECMWF HAS THE BROADER RIDGE. BOTH GFS AND ECMWF BRING A SHORTWAVE THROUGH THE AREA ON MONDAY. THIS PUSHES A WEAK FRONT OR SURFACE TROUGH THROUGH. MODELS DO NOT REALLY MOVE THIS BOUNDARY COMPLETELY THROUGH AS IT EITHER HANGS UP OR WASHES OUT. AGAIN THE ECMWF IS WARMER. CONSIDERING THE FLOW ALOFT...LIKE THE WARMER SOLUTION...BUT AM LEARY OF BOUNDARY POSITION AND STRENGTH. SUNDAY NIGHT AND ESPECIALLY MONDAY NIGHT LOOKS MILD FOR THIS TIME OF YEAR. TUESDAY THROUGH THURSDAY...AS WITH PREVIOUS RUNS...THE GFS IS SHOWING UPPER LEVEL FLOW BECOMING MORE ZONAL ON TUE. HOWEVER..THIS IS NOW THE OUTLIER AS THE ECMWF AND CANADIAN SHOW A H5 RIDGE OVER THE CENTRAL PART OF THE COUNTRY AND H85 TEMPERATURES NEAR 20C. AS A RESULT...HIGHS FOR TUES WERE INCREASED INTO THE 70S. A COLD FRONT IS STILL EXPECTED WED...THERE IS STILL SOME DISAGREEMENT BETWEEN MODELS ON TIMING OF THE FRONT. FORECAST FAVORS THE FASTER SOLUTIONS BRINGING THE FRONT IN ON WED MORNING. HOWEVER...IF THE TIMING IS DELAYED... FORECAST WILL NEED TO BE CHANGED ESPECIALLY TO LOWER MAX TEMPS ON WED. FLOW BEHIND THE FRONT DOES NOT SUPPORT ANY SIGNIFICANT MOISTURE ADVECTION...THEREFORE ONLY VERY LOW POPS ARE IN THE FORECAST. THANKS TO ALL FOR COLLABORATION. && .AVIATION...VFR CONDITIONS WILL DOMINATE THE ENTIRE TAF PERIOD. WINDS FROM THE SOUTH AT ABOUT 15 MPH WILL BECOME LIGHT AND VARIABLE BY 00Z. A COLD FRONT WILL BEGIN TO MOVE THROUGH THE AREA FROM THE NORTHWEST BY ABOUT 10-12Z...BRINGING SCATTERED HIGH LEVEL CLOUDS...POSSIBLY A FEW LOW LEVEL CLOUDS MORE LIKELY AT KMCK THAN KGLD...AND WINDS FROM THE NORTH AT 10 TO 15 MPH. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER/SFJ/BLM ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 425 PM EDT THU OCT 25 2007 .SHORT TERM (TONIGHT AND FRI)... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A BROAD MID/UPPER RIDGE EXTENDING FROM THE SRN ROCKIES TO THE GREAT LAKES. TRAPPED FOR THE TIME BEING UNDER THE RIDGE...A MIDLEVEL LOW WAS OVER THE LWR MISSISSIPPI VALLEY. TO THE W...A PROGRESSIVE POSITIVE TILT TROF EXTENDS FROM NRN MANITOBA TO OREGON. IT IS THIS TROF AND ITS INTERACTION WITH THE LWR MISSISSIPPI VALLEY SYSTEM THAT WILL BE OF INTEREST FOR THE WEATHER HERE FRI/SAT. CLOSER TO HOME...OVERWATER INSTABILITY WAS SUFFICIENT FOR LAKE EFFECT CLOUDINESS NEAR LAKE MICHIGAN FROM KMNN TO KESC AND KISQ LAST NIGHT THRU EARLY AFTN...BUT MODERATING AIRMASS AND MIXING OF DRIER AIR FROM ALOFT HAS WORKED TO DISSIPATE THE CLOUDS RECENTLY. OTHERWISE...PLENTY OF SUNSHINE HAS BEEN THE RULE ACROSS THE FCST AREA TODAY. WITH E-W SFC RIDGE AXIS LINGERING ACROSS UPPER MI AND WITH A MIN PRECIPITABLE WATER AXIS OF 1/4 TO 1/3RD OF AN INCH OVER THE AREA FOR A PORTION OF THE NIGHT...RADIATIONAL COOLING WILL BE ENHANCED UNDER CLEAR SKIES. WHILE THERE MAY BE SOME INCREASE IN CLOUDS FROM THE S LATE...STILL EXPECT SUFFICIENT RADIATIONAL COOLING TO GO AT OR BLO THE LOW END OF MOS GUIDANCE IN MANY LOCATIONS. UPPER 20S/LWR 30S SHOULD BE COMMON OVER MUCH OF THE INTERIOR. MODELS ARE IN VERY GOOD AGREEMENT SHOWING TROF CURRENTLY OVER THE NW BEGINNING TO PICK UP MIDLEVEL LOW OVER THE LWR MISSISSIPPI VALLEY TONIGHT/FRI. ALL THE MODELS TAKE THE LOW TO SE MISSOURI FRI WHILE TROF OVER THE NW STATES MOVES TO MT AND THE DAKOTAS. WHILE THERE IS A GOOD SURGE OF MOISTURE...PARTICULARLY AT THE LOWER LEVELS AND ESPECIALLY OVER THE E...FORCING REALLY IS MEAGER FRI. AT THIS POINT...SEE NO REASON TO STRAY MUCH FROM INHERITED FCST WHICH ONLY HAD SLIGHT CHC POPS EXPANDING NW TO ROUGHLY A MUNISING/KIMT LINE IN THE AFTN WITH CHC POPS CONFINED TO THE KISQ/KERY VCNTY. && .LONG TERM(SAT NIGHT THROUGH THURSDAY)... MAIN FCST CONCERNS ARE PCPN TRENDS/TYPE INTO EARLY SUNDAY. FRI NIGHT INTO SAT...MODELS WERE IN DECENT AGREEMENT WITH THE EVOLUTION AND INTERACTION OF THE SRN MS VALLEY CUTOFF AND THE NRN STREAM SYSTEM MID/UPPER LEVEL TROUGH AFFECTING THE WESTERN GREAT LAKES. DEFORMATION AND 800-600 MB FGEN ASSOCIATED WITH THE SRN STREAM MID LEVEL LOW IS EXPECTED TO BRUSH MAINLY THE SE PORTION OF THE CWA...ESPECIALLY BTWN 06Z-18Z. 700-500 MB QVECTOR CONV AND ANOTHER BAND OF FGEN WILL ALSO AFFECT THE WRN CWA WITH THE NRN STREAM SHRTWV. UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 300 MB JET INTO NRN ONTARIO WILL ALSO AID LARGE SCALE ASCENT. HOWEVER...THE BEST MOISTURE (PWAT AROUND 0.80 INCH) WHILE MORE LIMITED MOISTURE TO THE WEST (PWAT AROUND 0.50 INCH WITH LITTLE INFLOW) WILL LEAD TO LIGHT PCPN WITH MORE SCT COVERAGE. THE NAM/GFS WET-BULB ZERO HEIGHTS (AOB 1500 FT AGL) AND 1000-850 MB THICKNESS THRESHOLDS SUGGESTS THAT POTENTIAL CHANGEOVER TO SNOW OR MIX WITH SNOW WEST WOULD OCCUR TOWARD 12Z SAT. 850 MB TEMPS TO NEAR -4C WILL ALSO BE ENOUGH FOR SOME LAKE ENHANCEMENT. AS THE NRN STREAM SHRTWV SWEEPS THROUGH THE AREA THE PCPN WILL TRANSITION TO PURE LAKE EFFECT DURING THE AFTERNOON. 850 MB TEMPS TO -8C WILL GIVE LAKE-H8 DELTA/T VALUES TO AROUND 17C. SAT NIGHT INTO SUN...LAKE EFFECT PCPN FOR NW FLOW FAVORED AREAS WILL PERSIST TIL WINDS BACK OFFSHORE SUNDAY AFTERNOON. MON-THU...THE 12Z GFS AND 00Z ECMWF WERE IN FAIRLY CLOSE INTO MON WITH THE TIMING/POSITION OF THE NEXT SHORTWAVE AFFECTING THE UPPER GREAT LAKES. THE BEST QVECTOR CONV AND ASSOCIATED ISENTROPIC LIFT WITH THE 850-700 MB FRONT SHOULD AFFECT MAINLY THE ERN CWA. THE CAA BEHIND THIS SYSTEM HAS TRENDED WEAKER. SO...POPS FOR ANY LAKE EFFECT WERE REDUCED AND LEFT AS -SHRA. PROGRESSIVE PATTERN BRINGS ANOTHER SHRTWV THROUGH SRN CANADA TOWARD THE UPPER GREAT LAKES WED WITH A SFC COLD FRONT MOVING THROUGH TUE NIGHT OR WED. THE SLOWER 00Z ECMWF...MORE IN LINE WITH THE GFS ENS MEAN...WAS PREFERRED. THIS WILL BRING ANOTHER CHANCE OF LIGHT RAIN SHOWERS FOLLOWED BY CAA AND LAKE EFFECT PCPN WED NIGHT INTO THU. MDLS HAVE TRENDED A BIT STRONGER WITH THIS SYSTEM BRINGING 850 MB TEMPS OF -10C INTO THE AREA WITH POTENTIAL FOR ACCUMULATING LAKE EFFECT SNOW. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... VFR CONDITIONS WILL PREVAIL THRU THIS FCST PERIOD WITH HIGH PRES RIDGE AND DRY AIRMASS OVER THE REGION. SKIES SHOULD GENERALLY BE CLR AT KCMX. AT KSAW...SKIES WILL GENERALLY BE CLEAR THRU TONIGHT...THEN SCT TO POSSIBLY BKN MID CLOUDS OR STRATOCU WITH BASES AOA 4KFT WILL ARRIVE LATE FRI MORNING AS LOW PRES LIFTS N TOWARD LWR MI. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... MAIN FOCUS FOR THIS FCST ISSUANCE IS THE POTENTIAL FOR GALES SAT. A COLD FRONT WILL CROSS LAKE SUPERIOR LATE FRI AFTN AND NIGHT AND THEN LOW PRES WILL DEEPEN AS IT LIFTS NE THRU THE CNTRL GREAT LAKES TOWARD QUEBEC FRI NIGHT AND SAT. STRENGTHENING COLD AIR ADVECTION W OF THE DEEPENING SFC LOW COMBINED WITH TIGHTENING PRES GRADIENT BTWN THE LOW PRES TO THE E AND HIGH PRES OVER THE DAKOTAS WILL RESULT IN INCREASING N TO NW WINDS OVER THE LAKE. WITH THE LOW-LEVEL TEMP PROFILE BECOMING UNSTABLE OVER THE WATER DUE TO THE INCREASINGLY COLD AIRMASS...STRONGER WINDS ALOFT WILL ALSO BE ABLE TO MIX DOWN TOWARD THE LAKE SFC. END RESULT SHOULD BE A PERIOD OF N TO NW GALES SAT INTO SAT EVENING...MAINLY OVER THE CNTRL AND ERN PORTION OF LAKE SUPERIOR. ANOTHER COLD FRONT CROSSING LAKE SUPERIOR LATE MON AFTN/EVENING MAY PRODUCE ANOTHER NW GALE OR NEAR GALE EVENT OVER ERN LAKE SUPERIOR MON NIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLB AVIATION...ROLFSON MARINE...ROLFSON mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 140 PM EDT THU OCT 25 2007 UPDATED AVIATION SECTION FOR 18Z TAFS .DISCUSSION (ISSUED AT 515 AM EDT)... WATER VAPOR LOOP AND RUC ANALYSIS SHOW A BROAD MID-UPR RIDGE STRETCHING FROM THE WRN GREAT LAKES THROUGH THE PLAINS TO THE SW STATES. THIS BROAD RIDGE IS FLANKED BY TROFS OVER WRN CANADA/PAC NW AND OVER ERN CANADA/NEW ENGLAND. ANOTHER FEATURE WHICH WILL AFFECT OUR WX FOR FRI INTO THE WEEKEND IS A CLOSED LOW OVER THE GULF COAST STATES. WITH RIDGE DOMINATING THIS MORNING OVER THE REGION SKIES HAVE BEEN MOSTLY CLEAR...EXCEPT FOR SOME LAKE EFFECT CLOUDS OVER FAR ERN UPR MI AND ALONG NRN LAKE MI COUNTIES. LACK OF CLOUDS AND LIGHT WINDS HAVE ALLOWED TEMPS TO FALL INTO THE 20S ACROSS MUCH OF INLAND FCST AREA...WITH LOWER 20S REALIZED OVER SOME OF THE WRN INTERIOR. WITH MID-LVL RIDGING STILL IN PLACE AND A WARM ADVECTION SRLY FLOW AHEAD OF THE NORTHERN PLAINS TROF...LOOK FOR 900 MB TEMPS OF 6-8C TO MIX TO THE SFC UNDER SUNNY SKIES...YIELDING HIGHS IN THE MID 50S ACROSS MUCH OF THE AREA WITH EVEN SOME UPPER 50S OVER THE WRN HALF. SFC RIDGE AXIS WILL LINGER OVER THE AREA TONIGHT AND MIN PRECIPITABLE WATER AXIS OF .25 INCH OVER THE AREA FOR MUCH OF THE NIGHT...RADIATIONAL COOLING WILL BE ENHANCED. WHILE THERE MAY BE SOME INCREASE IN CLOUDS FROM THE S LATE...STILL EXPECT ENOUGH RADIATIONAL COOLING FOR INLAND TEMPS TO LOWER TO THE UPPER 20S/LWR 30S WITH THE LOWEST READINGS OVER THE INTERIOR WEST...IN LINE WITH COOLER GFS MOS GUIDANCE. FRI...MODELS FINALLY COMING INTO BETTER AGREEMENT ON EVOLUTION/TRACK OF MID/UPPER LEVEL LOW AS IT LIFTS NNE AND ITS REMNANTS PHASE WITH NRN BRANCH SHORTWAVE OVER THE WEEKEND. MODEL CONSENSUS IS THAT THE LOW SHOULD DRIFT INTO SRN IL BY FRI EVENING AND THEN TRACK UP THE OHIO VALLEY EARLY SAT IN RESPONSE TO NRN BRANCH SHORTWAVE APPROACHING THE UPR GREAT LAKES AT THAT TIME. WITH DRY AIRMASS/RIDGING INITIALLY IN PLACE EARLY FRI FELT COMPELLED TO TRIM BACK SLIGHT CHC POPS FOR RAIN TO ONLY THE FAR SE PORTION OF THE CWA FOR FRI MORNING...THEN SPREAD SLIGHT CHC POPS INTO THE REST OF THE EAST FRI AFTERNOON AS BETTER MOISTURE AND WEAK Q-VECT CONV MOVE INTO THE AREA. AS DEEPENING SFC LOW LIFTS NORTH THROUGH LOWER MI FRI NIGHT...CYCLONIC NRLY FLOW BEHIND WILL INCREASE OVER UPR MI ESPECIALLY AFTER MIDNIGHT. SO HAVE KEPT IDEA OF INCREASING POPS ACROSS THE FCST AREA LATE FRI NIGHT WITH SOME LAKE ENHANCEMENT POSSIBLE AS 850 MB TEMPS LOWER TO 0 TO -3C TOWARD 12Z SAT. WITH 850 MB TEMPS CONTINUING TO FALL TO -6/-7C BY 00Z SUN ALONG WITH FREEZING LVLS...LOOK FOR SCATTERED LAKE EFFECT RAIN SHOWERS TO GRADUALLY MIX OR CHANGEOVER TO SNOW FROM THE WEST ON SAT. BETTER CHC OF SNOW SAT WILL BE OVER HIGHER TERRAIN AREAS OF WRN AND CENTRAL UPR MI AS FLOW BACKS NW THROUGH THE DAY. LONGER FETCH ACROSS ERN LAKE SUPERIOR MAY MODERATE LOW-LVLS AND KEEP PREDOMINANT PCPN-TYPE MORE RAIN THERE. GIVEN THAT THE MODELS SHOW THE FLOW BACKING THROUGH THE DAY AND BECOMING INCREASINGLY ANTICYCLONIC...WOULD NOT EXPECT A LOT OF ACCUMULATING RAIN OR SNOW AND DECIDED TO KEEP POPS AT 30/40 PCT ALONG THE NRN TIER COUNTIES. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... VFR CONDITIONS WILL PREVAIL THRU THIS FCST PERIOD WITH HIGH PRES RIDGE AND DRY AIRMASS OVER THE REGION. SKIES SHOULD REMAIN CLR AT KCMX. AT KSAW...SKIES WILL GENERALLY BE CLEAR THRU TONIGHT...THEN SCT TO POSSIBLY BKN MID CLOUDS OR STRATOCU WITH BASES AOA 5KFT WILL ARRIVE LATE FRI MORNING/AFTN AS LOW PRES LIFTS N TOWARD LWR MI. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... PRESSURE FALLS AHEAD OF LOW PRESSURE SYSTEM SHIFTING ACROSS NORTHERN ONTARIO TODAY COULD LEAD TO LOCALIZED WINDS ABOVE 25 KNOTS OVER FAR NORTHERN SECTIONS OF THE OPEN LAKE. OTHERWISE...WINDS NEXT 24-36 HRS WILL STAY BELOW 25 KNOTS AS HIGH PRESSURE OVER REGION SLOWLY PRESSES EAST. NEXT OPPORTUNITY FOR STRONGER WINDS DEVELOPS LATE FRIDAY NIGHT INTO SATURDAY. LOW PRESSURE SYSTEM LIFTING NORTHEAST OUT OF THE MISSISSIPPI RIVER VALLEY COMBINES WITH STRONG HIGH PRESSURE TO THE WEST TO SET UP TIGHT PRESSURE GRADIENT. COLD AIR ADVECTION BECOMES SUBSTANTIAL TOO WHICH INCREASES LOWER LEVEL INSTABILITY ALLOWING STRONG WINDS ALOFT TO MIX TO THE SFC OR AT LEAST C-MAN AND SHIP LEVEL. GALES REMAIN POSSIBLE SATURDAY INTO SATURDAY EVENING...MOSTLY OVER CENTRAL AND EASTERN LAKE SUPERIOR. WINDS DIMINISH LATER SATURDAY NIGHT INTO SUNDAY AS A HIGH PRESSURE RIDGE SETTLES OVER THE REGION. WINDS MAY EXCEED 25 KNOTS AGAIN ON MON AHEAD OF STRONG COLD FRONT. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...VOSS AVIATION...ROLFSON MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1244 PM CDT THU OCT 25 2007 .UPDATE... UPDATED FORECAST TO REFLECT CURRENT PRECIPITATION TRENDS. LARGE AREA OF LIGHT RAIN EARLIER THIS MORNING ON NWRN FRINGE OF UPPER LOW HAS DIMINISHED QUICKLY AS IT ENCOUNTERED DRY AIR OVER MO/IL. 850MB DEWPOINT DEPRESSIONS AT ILX AND SGF WERE 23C AT 12Z THIS MORNING. PAST TWO RUNS OF THE RUC DOES SHOW AN INCREASE IN MID LEVEL FRONTOGENSIS AND MOISTURE CONVERGENCE OVER THE THE CWA BY 21Z...SO HAVE HELD ONTO THE LIKELY POPS THROUGH THIS AFTERNOON. ADJUSTED CLOUDS BASED ON SATELLITE GRIDS...AND TEMPERATURE GRIDS ARE A BASED ON RAIN AND CLOUD TRENDS. BRITT && .DISCUSSION... STRONG UPPER LEVEL STORM SYSTEM LOOKS LIKE IT BOTTOMED OUT JUST NORTH OF MOBILE ALABAMA AROUND 01Z LAST NIGHT AND THE CENTER IS ALREADY STARTING TO WOBBLE BACK TO THE NORTH. ALL SHORT RANGE MODELS HAVE COME INTO GOOD AGREEMENT THROUGH ABOUT 12Z FRIDAY MORNING IN BRINGING THE LOW CENTER UP THROUGH THE LOWER MISSISSIPPI VALLEY INTO THE BOOTHEEL BY THAT TIME. WHILE MODEL SOLUTIONS DIVERGE SLIGHTLY AFTER 12Z FRIDAY MORNING...THE DIFFERENCES ARE MINOR AND SHOULDN`T AFFECT SENSIBLE WEATHER AT THE SURFACE SIGNIFICANTLY. REGARDLESS OF THE EXACT TRACK OF THE LOW...THE FORECAST REMAINS COOL AND DAMP THROUGH FRIDAY FOR MOST OF THE AREA. NORTHERN PORTIONS OF THE CWFA PROBABLY WILL NOT SEE AS MUCH RAIN AS SOUTHERN PORTIONS...BUT AREAS OF DRIZZLE AND SCATTERED SHOWERS WILL EVENTUALLY REACH EVEN UP TO THE HANNIBAL AND QUINCY AREAS. RAINFALL AMOUNTS WILL PROBABLY STAY FAIRLY LIGHT UP THERE...PERHAPS NOT EVEN REACHING 1/4 INCH...BUT THE SOUTHERN 3/4 OF THE CWFA SHOULD GET A GOOD SOAKING RAIN OVER THE NEXT 48 HOURS AS THE LOW MOVES OVERHEAD. CLOUDS AND PRECIP WILL KEEP DAYTIME TEMPERATURES SUPPRESSED...GOING FORECAST LOOKS LIKE IT HANDLES THIS WELL SO HAVE MADE VERY LITTLE CHANGE IN THIS RESPECT. SINCE THE MODELS SEEM TO HAVE COME TO A BETTER CONSENSUS I`VE RATCHETED UP THE POPS TO LIKELY/CATEGORICAL ACROSS MUCH OF SOUTHEAST AND EAST CENTRAL MISSOURI AND SOUTHWEST ILLINOIS THROUGH FRIDAY. RAIN SHOULD FINALLY COME TO AN END ON FRIDAY NIGHT WITH POTENTIALLY SOME SPRINKLES LINGERING INTO SATURDAY MORNING. IT STILL LOOKS PRETTY COOL FOR THE WEEKEND AS A COLD CANADIAN AIRMASS DROPS THROUGH THE PLAINS INTO THE MIDWEST. 850MB TEMPS FALL TO NEAR OR BELOW 0C DEPENDING ON WHICH MODEL YOU LOOK AT. HAVE TRENDED TEMPS DOWNWARD OUT OF THE 60S ON SUNDAY FOR THIS REASON. MONDAY MORNING COULD BE THE COLDEST WEATHER WE`VE SEEN THUS FAR THIS FALL ESPECIALLY IN SHELTERED AREAS IN THE OZARKS IF THE RIDGE AXIS DRIFTS DOWN INTO SOUTHEAST MISSOURI AND SOUTHERN ILLINOIS. FORECAST CONTINUES TO LOOK COOL AND DRY THROUGH THE FIRST PART OF NEXT WEEK. CARNEY && .AVIATION... FOR THE 18Z TAFS... LARGE AREA OF MVFR/LOCAL IFR CIGS HAS SPREAD INTO KSUS/KSTL FROM THE SOUTHEAST THE PAST COUPLE OF HOURS. THE RAIN ASSOCIATED WITH THESE CIGS HAS DECREASED RAPIDLY IN AREAL EXTENT THE PAST FEW HOURS BECAUE IT IS ENCOUTERING DRIER AIR...THOUGH DO EXPECT SOME REDEVELOPMENT OF THE RAIN LATE THIS AFTERNOON AND HAVE REFLECTED THIS IN THE TAFS. BECAUSE OF THE DRIER...DO NOT EXPECT THE MVFR CIGS TO REACH KCOU/KUIN UNTIL AFT 00Z. CIGS WILL CONTINUE TO LOWER...AND DO EXPECT WIDESPREAD IFR CIGS AFT 06Z WITH ADDITIONAL RAIN OVERNIGHT. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo