AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 943 AM CDT THU OCT 14 2004 .SYNOPSIS...COLD FRONT NOW INTO WESTERN LOUISIANA WILL MOVE THROUGH SOUTH CENTRAL LOUISIANA BY LATE MORNING. RAIN WILL END FROM THE NORTHWEST WITH CLEARING SKIES. LOW TEMPERATURES WILL BE REACHED OVER THE NEXT FEW HOURS. && .DISCUSSION...WILL BLEND THE LATEST NGM MOS WITH THE AFTERNOON RUC AND TWEAK TEMPS DOWN...AS MUCH AS 3 DEGREES FOR SOUTHERN ZONES WHERE CLOUD COVER WILL HOLD DOWN TEMPS FOR AT LEAST THE EARLY AFTERNOON HOURS. WILL ALSO ZERO OUT POPS FOR ALL EXCEPT S CEN LA WHERE 50 PERCENT WILL REMAIN WITH EARLY WORDING. MAY NEED TO CONSIDER A LAKE WIND ADVISORY FOR COASTAL COUNTIES/PARISHES OF JEFFERSON AND CAMERON AS SUSTAINED WINDS LOOK TO INCREASE CLOSE TO 20 MPH. && .MARINE...SCA WILL CONTINUE WITH TIGHT NORTHERLY GRADIENT AND COLD AIR ADVECTION OVER WARM WATERS. && .AVIATION...IMPROVING CIGS TO VFR OVER THE NEXT FEW HOURS. JS-PUBLIC JT-MARINE/AVIATION ...previous... .DISCUSSION... COLD FRONT CURRENTLY LOCATED IN NORTH CNTRL LA DOWN THROUGH THE SAN ANTONIO AREA. TEMP/DEW PT GRADIENT ABOUT 10 TO 15 DEGREES ACROSS FRONT. MOST OF THE SHRA/TSRA ACTIVITY IS IN SOUTHERN TX AND MVG EAST ALONG THE FRONT. UPR TROUGH IS LOCATED IN NW IA DOWN THROUGH CNTRL KS AND INTO WESTERN TX. FRONT WILL CONTINUE TO PROGRESS SOUTHEASTWARD THIS MORNING AND SHOULD REACH THE COAST AROUND DAYBREAK. AS FRONT APPROACHES OUR CWA EXPECTING HIGHER COVERAGE OF SHRA/TSRA IN SE TX...SW AND S CNTRL LA WHERE THE RR QUAD OF THE U/L JET MAX WILL PROVIDE FOR ADDITIONAL SUPPORT OF CONVECTIVE ACTIVITY. FCST SOUNDINGS IN THE COASTAL COUNTIES AND PARISHES NOT TOO IMPRESSIVE AROUND DAYBREAK AND AFTERWARDS AS FRONT WILL HAVE MOVED THROUGH BY THAT TIME. HPC SHOWS HEAVIEST RAINFALL REMAINING OFFSHORE AND BOTH THE GFS AND ETA AGREE WITH THIS SOLUTION. TEMPS WILL NOT RISE MUCH IN OUR AREA DUE TO EARLY FRONTAL PASSAGE AND THIS WILL HELP IN KEEPING ANY SIGNIFICANT TSRA FROM DEVELOPING. THE AREAS THAT SEE DAYTIME HEATING BEFORE FRONTAL PASSAGE WILL HAVE MORE A SVR TSRA THREAT...BUT THIS LOOKS TO BE WELL EAST OF OUR CWA. AS FRONT QUICKLY MOVES SE OF THE AREA ALL PRECIP WILL MOVE OUT OF OUR SE ZONES BY THE EVNG HOURS. THIS WILL ALLOW FOR A PRETTY COOL NIGHT TONIGHT WITH LOWS IN THE MID 40S NORTH TO AROUND 50 SOUTH. HIGHS ON FRIDAY WILL ONLY BE IN THE MID TO UPR 70S. SOUTHERLY WINDS BACK TO THE AREA BY SATURDAY WILL WARM THINGS UP TO AROUND NORMAL AND ABOVE NORMAL TEMPS EXPECTED SUNDAY. NEXT CHANCE FOR RAIN WILL BE MID-WEEK WITH S/W'S MVG AROUND THE BASE OF A LONGWAVE TROUGH EXPECTED IN THE CNTRL US BY TUES. .MARINE... SCA WILL CONTINUE TODAY WITH STRONG NORTHERLY WINDS EXPECTED BEHIND THE FRONT. WINDS WILL GRADUALLY SUBSIDE ON FRIDAY AS FRONT MVS FURTHER SE OF THE AREA. .AVIATION...SOME MVFR CONDITIONS DUE TO CEILINGS ARE LIKELY BEFORE THE FRONTAL PASSAGE...WITH IFR CONDITIONS DUE TO CEILINGS AND VISIBILITIES IN AND NEAR THE SHOWER/THUNDERSTORM ACTIVITY WILL BE POSSIBLE. AFTER FRONTAL PASSAGE...SHOWER ACTIVITY IS EXPECTED TO END WITH CEILINGS BEGINNING TO LIFT. GUSTY NORTHWEST TO NORTH WINDS ARE ALSO EXPECTED TO DEVELOP AFTER THE FRONTAL PASSAGE...THEN SUBSIDE LATER TONIGHT. RUA && .UPDATED POINT TEMPS/POPS... BPT 70 51 79 60 / 0 00 00 00 LCH 69 50 78 58 / 0 00 00 00 LFT 69 49 76 58 / 50 10 00 00 AEX 66 45 75 54 / 0 00 00 00 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...SCA...GMZ450-455-470-475. TX...SCA...GMZ450-470. && $$ MCNATT/JS la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 915 PM EDT THU OCT 14 2004 .UPDATE... RADAR SHOWS AN AREA OF RAIN ACROSS CENTRAL NEW HAMPSHIRE...WITH THE MAIN AREA OF RAIN EAST OF CAPE COD. LATEST SCANS SHOW AN AREA OF RAIN BLOSSOMING IN THE GULF OF MAINE HEADING EAST. 21Z RUC SHOWS .25 QPF ALONG THE MID COAST...AND THE 18Z GFS IS ALSO MORE GENEROUS ON QPF. BASED ON THIS AND RADAR WILL BUMP UP POPS A TAD TO CATEGORICAL ALONG THE MID COAST...AND LIKELY ELSEWHERE. OTHERWISE...TEMPERATURES RUNNING NEAR FORECAST LOWS...WHICH IS EXPECTED GIVEN THE CLOUD COVER. NO OTHER CHANGES NEEDED. && .PREVIOUS DISC... SHORT TERM (TONIGHT THROUGH FRIDAY)... PRECIPITATION OVER SOUTHERN NEW ENGLAND THIS AFTERNOON IS PROGRESSING NORTH ABOUT ON SCHEDULE. THE PRECIPITATION IS PUSHING INTO SOME VERY DRY AIR OVER WESTERN MAINE AND NEW HAMPSHIRE AS SHOWN ON THE 12Z GYX UPPER AIR SOUNDING. STILL EXPECT THE RAIN TO OVERSPREAD THE FORECAST AREA TONIGHT BUT AMOUNTS SHOULD BE RELATIVELY LIGHT. 12Z MODELS SHOWED BETTER CONSENSUS WITH THE BEST LIFT OVERNIGHT REMAINING OFFSHORE. THIS IS REFLECTED IN THE CONVECTION OFFSHORE OF SOUTHERN NEW ENGLAND THIS AFTERNOON. GIVEN THIS SITUATION, EXPECT THE HIGHEST POPS ALONG THE COAST WITH CHANCE POPS OVERNIGHT TO THE NORTH AND WEST. THIS FIRST BATCH OF PRECIPITATION MOVES THROUGH TONIGHT AND TAPERS OFF FRIDAY MORNING. CANNOT RULE OUT A CHANCE OF RAIN FRIDAY AFTERNOON AHEAD OF A STRONGER SYSTEM THAT ARRIVES FRIDAY NIGHT, HOWEVER MOS POPS LOOK TOO HIGH FOR FRIDAY. MET/MAV MOS MAX/MIN TEMPERATURE GUIDANCE IN REASONABLY GOOD AGREEMENT FOR TONIGHT AND FRIDAY AND USED A COMPOSITE OF THE GUIDANCE FOR THE OFFICIAL FORECAST TEMPERATURES. .LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... DEEP UPPER TROF TILTING NEGATIVE AS IT SWINGS THROUGH THE EASTERN GREAT LAKES FRIDAY EVENING DEVELOPS SECONDARY SURFACE LOW ALONG THE MID ATLANTIC COAST AND PULLS THIS SYSTEM TO THE NORTH OVERNIGHT. NEW MODEL RUNS TAKING THIS LOW UP THE CONNECTICUT VALLEY FRIDAY NIGHT BRINGING WITH IT A BRIEF PERIOD OF MODERATE TO HEAVY RAIN AND STRONG WINDS. A PERIOD OF GALE FORCE WINDS POSSIBLE FOR THE OFFSHORE WATERS BUT SOME QUESTION AT THIS TIME JUST HOW MUCH WIND WILL MIX DOWN. DRY SLOT QUICKLY CUT PRECIP OFF AFTER MIDNIGHT. SURFACE LOW TURNS NORTHWEST ON SATURDAY AND BECOMES TRAPPED UNDER UPPER CLOSED CIRCULATION WEST OF THE FORECAST AREA. SOME MORNING SHOWERS POSSIBLE...ESPECIALLY EARLY...BUT THINK MUCH OF THE DAY WILL BE DRY BUT MOSTLY CLOUDY AND BLUSTERY AS COLDER AIR POORS IN FROM THE WEST. UPPER LOW GRADUALLY LIFTS NORTH SATURDAY NIGHT WELL WEST OF THE FA WITH ANY SHOWER ACTIVITY GENERALLY CONFINED TO FAR NORTHWEST ZONES. ABUNDANT LOW LEVEL MOISTURE LINGERS IN THE AREA ON SUNDAY...BUT LIKE SATURDAY...MAINLY SHOWER FREE. NEXT SYSTEM QUICKLY HEADS EAST IN FAST WESTERLY FLOW AND CURRENTLY PROJECTED TO REACH NEW ENGLAND MONDAY AFTERNOON BEFORE DEPARTING THE AREA ON TUESDAY. && .AVIATION...COASTAL STRATUS AND AREAS OF FOG WILL MOVE IN THIS EVENING AND OVERNIGHT FROM THE EAST. THUS VFR CONDITIONS WILL DETERIORATE TO IFR. IFR CONDITIONS CONTINUE FRIDAY MORNING. && .MARINE... SMALL CRAFT ADVISORY TO CONTINUE. PAST EXPERIENCE WITH NORTHEAST FLOW SUGGESTS WINDS TEND TO BE STRONGER THAN MODELS. WINDS ALREADY 15 TO 20 KTS...WITH TIGHTENING GRADIENT. BUMP UP WINDS A TAD...AND MENTION GUSTS TO 25 KTS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FOR SEAS. && $$ SHORT TERM...WHEELER LONG TERM...EJS UPDATE...APFFEL me AREA FORECAST DISCUSSION...CORRECTED TO REMOVE NRN SCHOOLCRAFT FM HIGH NATIONAL WEATHER SERVICE MARQUETTE MI WIND WATCH 415 PM EDT THU OCT 14 2004 .DISCUSSION... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW HI AMPLITUDE PATTERN DVLPG ACRS NAMERICA WITH DEEPENING TROF IN THE CNTRL BTWN RDGS ON THE W AND E COASTS. CWA IN WEAK CYC NE FLOW BTWN SFC-H85 RDG OVER FAR NRN ONTARIO AND LO NOT FAR FM DTX (MSLP 1000MB). BROAD AREA OF PRES FALLS NOTED ARND THIS LO. ABUNDANT LO CLD PREVAILS ACRS THE FA IN FLOW OFF LK SUP UNDER SHARP INVRN H9-85 AS SHOWN ON 12Z GRB/APX SDNGS. ALTHOUGH HIER RH APRNT ABV H7 AT BOTH SITES... SNDGS SHOW VERY DRY AIR BTWN INVRN BASE AND HIER MID/UPR RH (DWPT DEPRESSIONS UP TO 20C WITHIN THIS LYR). LO CLD EXTENDS BACK INTO MN...WHERE 12Z INL SDNG SHOWS DRY AIR EVEN BLO INVRN AT H9. BUT THE 12Z DTX SDNG CLOSER TO THE LOWER GRT LKS LO INDICATES DEEP MSTR THRU THE ENTIRE TROP. OTRW...A CUTOFF LO MOVING THRU BASE OF UPR TROF IN THE SNCTRL MS VALLEY (00Z-12Z HGT FALLS UP TO 200M AT MKC). ANOTHER POTENT SHRTWV ON WV IMAGERY NOTED DIGGING THRU SCNTRL CAN (WITH 12HR H3 HGT FALLS UP TO 220M AT YQD) ACCOMPANIED BY 996MB SFC LO JUST N OF LK WINNIPEG. A NW H3/H5 JET MAX WITH WIND SPEEDS UP TO 150KT/90KT DIGGING WITH THIS SHRTWV INTO THE CNTRL TROF. MAIN FCST CONCERNS THIS PACKAGE INCLUDE IMPACT OF STRENGTHENING SFC LO NR DTX THAT WL ACCOMPANY PHASING OF SHRTWVS IN DEEPENING CNTRL NAMERICA TROF. PSBL IMPACTS INCLUDE HI WINDS/LK ENHANCED RASN/HI WAVES ACRS LK SUP. WL BE RELYING PRIMARILY ON THE GFS FOR THIS EVENT AS THIS MODEL SHOWS A MORE RPDLY DEEPENING CYC THAT WOULD BE FAVORED GIVEN THE UPR PATTERN AND TIME OF YEAR/LK AGGREGATE WRMG AS WELL AS THE MODEL TREND FOR A DEEPER/FARTHER W LO PRES TRACK. FOR TNGT...MODELS SHOW CNDN SHRTWV DIGGING FURTHER INTO CNTRL UPR TROF...WHICH THEN TAKES ON A MORE NEGATIVE TILT IN RESPONSE TO THE PHASING UPR SYS. IN RESPONSE...MSLP FALLS ALSO FCST OVER THE LOWER GRT LKS. AS UPR WINDS BACK IN RESPONSE TO THESE DYAMICS...EXPECT THE DEEPER MSTR OVER DTX TO WRAP BACK INTO THE ERN CWA. HOWEVER...DUE TO THE ANTECEDENT DRY AIR...THE RATHER LGT WINDS FCST IN THE CRITICALLY DRY LYR (WEAK ISENTROPIC LIFT)...AND LACK OF DPVA/SGNFT QVECTOR CNVGC...THINK PCPN WL BE ON THE LGT SIDE. WL UPGRADE POPS OVER THE E TO CATEGORICAL BUT TAPER TO 30-40 PCT OVER THE W AND DELAY ONSET OF PCPN OVER THE W IN LINE WITH MODEL QPF/EXPECTED DYNAMICS AND IMPACT OF DRY AIR. LOWER TROP TOO WARM/SFC DWPTS (35 TO 40) TOO HI TO WORRY ABOUT SN...JUST RA. UPR TROF CONTINUES TO BECOME MORE NEGATIVELY TILTED ON FRI...AND BOTH ETA/GFS SHOW SFC LO DEEPENING TO ARND 985MB OVER LK HURON BY 00Z SAT. GFS FCSTS SHARPENING CYC FLOW AND INCRSG UPR DVGC/H85-5 QVECTOR CNVGC/H7 OMEGA OVER THE E HALF OF FA BY 00Z SAT...WITH AXIS OF SHARPENING H85-7 FRONTOGENESIS OVER THE CNTRL FA. SO EXPECT RA INTENSITY TO PICK UP THEN ACRS THE E LATE IN THE DAY. BUT WL ALSO GO CATEGORICAL FOR POPS OVER THE W AS WELL...BUT FOR LIGHTER QPF. DEEPENING PROCESS PROGGED TO CONT FRI NGT AS UPR LO CLOSES OFF ACRS THE CNTRL GRT LKS...WITH PREFERRED GFS SHOWING SFC LO REACHING JUST E OF ANJ BY 12Z SAT AND INTENSIFYING TO 978 MB. GFS INDICATES INTENSE H85-5 QVECTOR CNVGC/UPR DVGC/H85-7 FRONTOGENESIS/H7 OMEGA OVER THE E HALF OF CWA JUST ON CYC SIDE OF H5 LO TRACK...BUT CATEGORICAL POPS IN ORDER EVERYWHERE WITH DEEP CYC FLOW/MSTR. GFS SHOWS H85 WINDS INCRSG TO 45 KTS OVER SCNTRL LK SUP BY 12Z SAT NR BASE OF INVRN. SINCE GFS SHOWS H100-85 THKNS SINKING BLO 1300M BY 12Z SAT OVER THE W...WL MENTION A MIX WITH SN W OF A LINE FM THE KEWEENAW TO IMT. ON SAT-SAT NGT...GFS SHOWS SFC LO MARCHING SLOWLY N TO JAMES BAY BY 00Z SUN AND INTO SRN HUDSON BAY BY 12Z SUN. AS THE SFC LO DRIFTS NWD...THE SHARP H85-5 QVECTOR CNVGC/UPR DVGC/H85-7 FRONTOGENESIS/H7 UVV DIMINISHES BY LATER SAT. ALTHOUGH HEAVIER PCPN WL GRDLY DIMINISH FOLLOWING THE EXIT OF THESE DYNAMICS...CONTD SHARP CYC FLOW/DEEP MSTR AND ARRIVAL OF A BIT COLDER AIR AT H85 WL CONT WDSPRD...BUT LIGHTER SHRASN. PCPN SHOULD DIMINISH MORE QUICKLY SAT NGT ESPECIALLY OVER THE SCNTRL ZNS AS DEEPER MSTR PROGGED TO DEPART WITH LINGERING DOWNSLOPING STRG NW FLOW. ALTHOUGH H85 TEMPS PROGGED TO FALL TO -5 TO -6C (VS 8-10C LK TEMP) BY LATE SAT NGT...THINK LK EFFECT/LK ENHANCED SN WL BE MINIMIZED BY STRG WINDS. ETA/GFS FCST SDNGS SHOW INTENSE INSTABILITY OVER THE LK SAT EVNG BLO INVRN ARND H85 WITH NW WINDS 40-50 KTS WITHIN THE MIXED LYR OVER ERN LK SUP. 06Z ETA HAD SHOWN 60-65KT WINDS WITHIN THE MIXED LYR. ALTHOUGH EXPLICIT GUIDANCE INDICATES LESS OF A THREAT FOR STRG WINDS THAN THE 06Z ETA...PATTERN RECOGNITION WITH PHASING STRG SHRTWVS RESULTING IN A NGETATIVELY-TILTED CUTOFF LO DURING THE FALL OVER THE LKS WHEN LK AGGREGATE WRMG WELL FURTHER INTENSIFY SFC CYC FURTHER SUGS THE NEED FOR A HIGH WIND WATCH ATTM ON SAT-SAT EVNG. ONE MINUS FOR HI WINDS WOULD BE A LACK OF STRG CAD AND STRG ISALLOBARIC WIND...AND WATCH MAY END UP AS AN ADVY IF EXPLICIT MODEL GUIDANCE WORKS OUT. SO WL RESTRICT WATCH TO THOSE MORE EXPOSED AREAS OVER THE KEWEENAW PENINSULA AND E OF MQT NR THE DESTABILIZING INFLUENCE OF LK SUP. ALSO PLAN TO ISSUE COASTAL FLOOD WATCH FOR THESE EXPOSED LOCATIONS AS WAVE HGTS 20 TO 25 FT PSBL IN NRSHORE AREAS IN PERSISTENT STRG NW FLOW AND LK LEVELS CLOSER TO LONG TERM AVG THAN IN RECENT YEARS. IN THE MEDIUM AND EXTENDED RANGE...MODELS SHOW DEEP VORTEX GRDLY EXITING TO THE NE ON SUN. BUT GIVEN MODEL TRENDS FOR THIS LO TO BE DEEPER AND SLOWER TO DEPART AS WELL AS UPSTREAM H85 THERMAL TROF... WL HANG ON TO CYC FLOW -SHRASN THRU THE MRNG BEFORE SHRTWV RDGING GRDLY ENDS THIS PCPN AND RESULTS IN SOME CLRG. THEN SOME DIFFERENCES ON THE TRACK OF NEXT SHRTWV THAT MODELS HAVE BEEN SHOWING IMPACTING THE GRT LKS ON MON. THERE HAS BEEN A TREND FOR THIS SYS TO MOVE FARTHER S BASED ON SLOWER DEPARTURE OF WEEKEND STORM...AND LATEST NCEP MANUAL GUIDANCE SHOWS SFC LO CENTER TRACKING THRU THE LWR GRT LKS. 00Z GFS ENSEMBLE GUIDANCE SHOWS A VARIATION BTWN 10 PCT AND 59 PCT POP IN THE 00Z-12Z MON TIME FRAME AT MQT. GIVEN MODEL TREND AND SLOWER DEPARTURE OF WEEKEND STORM THAT WOULD FORCE A SLOWER/FARTHER S TRACK...HAVE OPTED TO DELAY ONSET OF PCPN UNTIL SUN NGT AND SHIFT HIER POPS (UP TO 40 PCT) TO THE SRN ZNS WITH MARGINAL 30 POPS FARTHER N. H85 TEMPS BTWN 0 AND -5C WARRANT AT LEAST A MENTION OF RA/SN MIX INLAND FM LK MI. THEN DRIER AND WARMER WX IN STORE LATER ON MON INTO WED WITH MODEL CONSENSUS SHOWING TROFFING IN THE W... RISING HGTS OVER THE E...AND SFC HI PRES DOMINATING THE GRT LKS. WL CONT CHC -SHRA LATER ON WED INTO THU WITH APRCH OF LO PRES TROF TO THE E OF WRN TROFFING. COORDINATED WITH APX/GRB/DLH. && .MQT WATCHES/WARNINGS/ADVISORIES...HIGH WIND WATCH SAT/SAT EVNG && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1010 AM EDT THU OCT 14 2004 .UPDATE... LEAD SHORTWAVE AHEAD OF LONGWAVE TROUGH JUST PROGRESSING THROUGH SOUTHEAST MICHIGAN. REGIONAL RADARS SHOW WIDESPREAD SHOWERS ALIGNED WITH THE SURFACE LOW OVER SOUTHERN HURON/SOUTHWEST ONTARIO...WITH PRECIP EXTENDING BACK ACROSS THE SAGINAW VALLEY/THUMB. SURFACE ANALYSIS SHOWS TROUGH HANGING BACK ACROSS SOUTHEAST MICHIGAN...WITH LOW-LEVEL MOISTURE POOLING ALONG IT. EARLY VIS SATELLITE/METARS SHOW LOW CLOUDS/FOG AND DRIZZLE ACROSS THE SOUTHERN CWA...WHERE DEEPER MOISTURE HAS ALREADY STRIPPED AWAY. WITH MAINLY LOW-LEVEL MOISTURE WITHOUT AN OVERHEAD CLOUD DECK...WOULD NOT EXPECT IT TO BE TOO PERSISTENT THIS MORNING. WILL UPDATE TO MENTION FOG IN THE SOUTH WHERE PRECIP HAS ENDED. ALSO DRIZZLE HAS DEVELOPED WITH ABUNDANT MOISTURE AND WEAK CONVERGENCE ALONG THE TROUGH. DTX RADAR SHOWS PATCHY WEAK ECHOES...BUT ENOUGH TO MENTION IN THE GRIDS AT LEAST DURING THE MORNING. WILL KEEP THE AFTERNOON FORECAST AS IT...LOW CHANCE POPS FOR SCATTERED SHOWERS. WITH SOME HEATING...1000-850MB LAPSE RATES INCREASE TO NEAR 9C ACROSS MUCH OF SOUTHEAST MICHIGAN. 09Z RUC IS A BIT DRIER THAN THE 06Z ETA AS FAR AS LOW-LEVEL MOISTURE. NO REAL LIFT TO SPEAK OF EITHER /GENERAL 850-500MB QVECTOR DIVERGENCE BETWEEN THE UPPER WAVES/. HOWEVER WILL STILL KEEP A LOW CHANCE GOING FOR ANY DIURNAL INSTABILITY SHOWERS THAT MAY DEVELOP. AS FOR SKY COVER...CLOUDS WILL HOLD ACROSS MUCH OF THE CWA. COULD SEE BETTER SUN ACROSS THE SOUTH...BUT WOULD EXPECT CU TO FILL IN WITH EVEN WEAK HEATING. && BRAVENDER .PREV DISCUSSION...220 AM EDT THU OCT 14 2004 STRONG WINDS TO IMPACT THE CENTRAL GREAT LAKES ON SATURDAY. TOO EARLY TO ISSUE ANY ADVISORIES AT THIS TIME...BUT IT CERTAINLY LOOKS LIKE WE COULD SEE AT LEAST ADVISORY CRITERIA. FOR TODAY... MID LEVEL CIRCULATION (700 MB LOW) TRACKING THROUGH SOUTHEAST MICHIGAN EARLY THIS MORNING. DRY AIR AND LACK OF FORCING HAS ALLOWED THE TRI-CITIES REGION TO ESCAPE SEEING MEASURABLE RAINFALL. HOWEVER...SOLID BATCH OF SHOWERS WAS LOCATED UNDERNEATH AND EAST OF THE CIRCULATION...WHERE THE GOOD 295K ISENTROPIC LIFT WAS OCCURRING. THIS CIRCULATION WILL CONTINUE TO SLOWLY HEAD OFF TO THE NORTHEAST THIS MORNING. WOULD EXPECT A LULL IN THE PRECIPITATION TODAY...AS UPPER LEVEL SHORTWAVE RIDGING MOVES OVERHEAD. DEEP LOW LEVEL MOISTURE AND LINGERING SURFACE TROUGH STILL MAY BE ENOUGH TO PRODUCE A FEW SPRINKLES OR LIGHT RAIN SHOWERS THROUGHOUT THE DAY...AND WILL THUS CARRY 30 POPS (OUTSIDE OF THE HIGHER POPS THIS MORNING ACROSS THE THUMB REGION). WITH SOLID LOW OVERCAST...NOT ANTICIPATING TEMPS CLIMBING MORE THAN 10 DEGREES. WILL CARRY MAXES AROUND 60 DEGREES. NOW TO THE BIG STORY... INTENSE STORM SYSTEM STILL ON TRACK TO DEVELOP ON FRIDAY...JUST A LOT FARTHER WEST THEN INDICATED YESTERDAY. THE REASON FOR THIS FARTHER WESTWARD DEVELOPMENT IS DUE TO THE POTENT SHORTWAVE OVER NORTHERN SASKATCHEWAN. THIS SYSTEM IS CHUCKING ALONG A LOT FASTER...AND WILL PHASE WITH THE UPPER LOW OVER THE CENTRAL MISSISSIPPI VALLEY/TENNESSEE VALLEY BY EARLY FRIDAY MORNING...ALLOWING THE LONGWAVE TROUGH TO GO NEGATIVE. WITH THE NEGATIVELY TILTED TROUGH AXIS SLOWLY PIVOTING THROUGH LOWER MICHIGAN ON FRIDAY...THAT SHOULD ASSURE US OF CATEGORICAL POPS...AS MOISTURE IS WRAPPED BACK INTO SOUTHEAST MICHIGAN...INTO FRIDAY NIGHT. CONSENSUS TRACK OF THE LOW BY THE MODELS (UKMET/ETA/GFS) IS FROM CENTRAL OHIO FRIDAY MORNING (992 MB) THROUGH CENTRAL/EASTERN LAKE ERIE DURING FRIDAY (987 MB) TO GEORGIAN BAY FRIDAY EVENING (980 MB) AND INTO CENTRAL ONTARIO/QUEBEC ON SATURDAY (970 MB). THIS IS NEAR BOMB CRITERIA...24 MB PRESSURE FALL IN 24 HOURS...WHICH WILL RESULT IN VERY STRONG WINDS OVER THE CENTRAL GREAT LAKES ON SATURDAY. STRONG COLD ADVECTION AND GOOD SUBSIDENCE ON SATURDAY WILL BE CONDUCIVE TO MIXING THE STRONGER WINDS TO THE SURFACE. HOWEVER...THE ONE SAVING GRACE LOOKS TO BE THE TIMING OF THE 6 HOUR PRESSURE COUPLET (12 MB)...WHICH IS OVER THE REGION 6Z SATURDAY. WITH THIS OCCURRING DURING THE NIGHT-HOURS...WE WILL HAVE A LITTLE MORE STABILITY AT THE SURFACE AND THUS LESS TURBULENT MIXING. NONE-THE-LESS...STRONG SUBSIDENCE BEHIND COLD FRONT STILL MAY BE ENOUGH TO GIVE US STRONG WINDS AS EARLY AS FRIDAY NIGHT. ON SATURDAY...850 MB WINDS PROGGED TO BE 45 TO 50 KNOTS. WITH CONTINUED COLD ADVECTION...DAYTIME HEATING...AND INVERSION HEIGHTS CLOSE TO 6000 FEET...WE SHOULD AT LEAST MAKE AN ATTEMPT TO MIX SOME OF THOSE WINDS DOWN. STEEP LOW LEVEL LAPSE RATES (LEADING TO LOW LEVEL CAPES OF 75 TO 100 J/KG)...COUPLED WITH CONTRIBUTIONS FROM LAKE MICHIGAN...SHOULD LEAD TO AT LEAST SCATTERED SHOWER DEVELOPMENT ON SATURDAY...AS 1000 TO 500 MB RH REMAINS HIGH (GREATER THAN 80 PERCENT). WE SHOULD BEGIN TO DRY OUT SATURDAY NIGHT AS HEIGHTS RISE AND SUBSIDENCE REALLY BEGINS TO TAKE OVER. HOWEVER...LAKE EFFECT ACTIVITY OFF OF LAKE MICHIGAN WILL LIKELY BE CONTINUING DUE TO THE GOOD INSTABILITY. DESPITE STRONG 850 MB WINDS CAUSING LOW RESIDENT TIME OF AIR PARCELS OVER THE LAKE MICHIGAN...WILL KEEP A LOW CHANCE POP IN FOR SOUTHEAST MICHIGAN...AS INVERSION HEIGHTS ARE SLOW TO FALL. SHORTWAVE RIDGING AT ALL LEVELS TO MOVE IN FOR SUNDAY. WILL KEEP THE FORECAST DRY...ALTHOUGH THERE STILL IS A SLIGHT CHANCE OF A LEFTOVER SHOWER IN THE MORNING. NOT ANTICIPATING MAKING ANY SIGNIFICANT CHANGES TO TEMPS IN THE GRIDS THROUGH THE FORECAST PERIOD. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SF EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 337 PM CDT THU OCT 14 2004 UPPER LOW WILL CONTINUE TO ROTATE INTO THE LOWER MISSISSIPPI VALLEY ...AND AS IT MOVES EAST...CFWA SHOULD SEE GRADUAL CLEARING FROM WEST TO EAST THIS EVENING. CLOUDS AND WEAK DOWNSLOPE COMPONENT TO THE WIND WILL DICTATE THE AMOUNT OF COOLING OVERNIGHT. PREVIOUS FORECAST MINIMUMS LOOK REASONABLE AND WILL NOT DEVIATE TOO MUCH. WILL ROTATE FROM NORTHERN PLAINS ACROSS CENTRAL AND SOUTHERN PLAINS ON FRIDAY WHICH WILL SPREAD SOME HIGH LEVEL CLOUDS INTO REGION BY AFTERNOON. SECONDARY SURGE OF COLD AIR WILL NOT ARRIVE UNTIL LATE IN THE DAY...AND WITH MODEST AMOUNT OF LOW LEVEL WARM ADVECTION/DOWNSLOPE COMPONENT EXPECTED...FEEL MAX TEMPERATURES WILL FALL SHORT OF SEASONAL NORMALS TOMORROW DUE TO HIGH LEVEL CLOUDINESS. COLDER AIRMASS WILL FILTER INTO THE REGION FRIDAY NIGHT INTO EARLY SATURDAY...GIVING MOST LOCATIONS THEIR COLDEST TEMPERATURES OF THE SEASON. MAY SEEM SOME FROST...BUT WILL WAIT A LITTLE BEFORE INTRODUCING IT INTO THE FORECAST. SF FOR THE WEEKEND...AND THROUGH THE MIDDLE OF NEXT WEEK...A COMPLEX FALL PATTERN WILL DOMINATE THE MIDWEST. SATURDAY WILL BEGIN WITH WITH A DEEP POLAR LOW EXITING THE MIDWEST AND LIFTING THROUGH THE EASTERN CONUS. COOL TEMPS (50S) WILL PREVAIL SATURDAY AS THE REMNANTS OF COLD AIR ADVECTION LINGER ABOUT KANSAS AND MISSOURI. FOR SUNDAY ALL THE MID RANGE MODELS GENERALLY AGREE THAT AS THE LOW LIFTS OUT OF THE PLAINS STATES THE PATTERN ACROSS THE REGION WILL SHIFT TO MORE OF A FAST ZONAL FLOW FOR EARLY NEXT WEEK. THIS WILL ALLOW FOR SOME WEAK RIDGING THAT WILL HELP PUSH TEMPS BACK UP (60S)...BUT WILL COMPLICATE THE FORECAST BY INTRODUCING DIFFICULT TO TIME FAST MOVING SHORT WAVES INTO THE FLOW FOR EARLY NEXT WEEK. THE PRIME EXAMPLE OF THIS WILL BE THE SHORTWAVE PROGGED TO MOVE THROUGH IN THE SOUTHERN FLOW LATE SUNDAY AND MONDAY. THIS WAVE IS THE REMAINS OF A CUTOFF LOW CURRENTLY OFF THE COAST OF CALIFORNIA. THE GFS IS MUCH MORE PROGRESSIVE WITH THIS SOUTHERN WAVE WHILE THE EXTENDED ETA (DGEX) PLACES MORE EMPHASIS ON A WAVE ON IN THE NORTHERN STREAM. FOR NOW I HAVE KEPT OUR GOING SLIGHT CHANCE (20%) POPS FOR SUNDAY AND MONDAY...WHILE MODERATING TEMPS ON MONDAY TO REFLECT THE INCREASE CLOUD COVER AND WEAK COOL AIR ADVECTION. WARM AIR ADVECTION WILL PREVAIL TUESDAY AND WEDNESDAY AS A DIGGING TROUGH MOVES INTO THE WESTERN CONUS...HELPING TEMPS TO PUSH BACK TOWARDS NORMAL. ON WEDNESDAY AND THURSDAY THE GFS AND DGEX MODELS QUICKLY SHOOT A SHORT WAVE THROUGH THE DIGGING TROUGH...WHICH IS PROGGED TO EXPAND ACROSS THE CONUS...WHILE THE ECMWF/UKMET/AND CANADIAN MODELS ARE SLOWER WITH THIS FEATURE. THE FACT IS THAT THE FEATURE IS THERE LENDS CREDENCE TO ITS EXISTENCE...AND POINTS TO A TIMING ISSUE. SO WHILE NOT OVERLY CONFIDENT DUE TO THE TIMING...I HAVE ADDED POPS FOR THE NORTHEAST HALF OF THE CWA FOR WARM AIR ADVECTION RAIN AHEAD OF THE SHORTWAVE WEDNESDAY...AND KEPT THE POPS THROUGH THURSDAY FOR WRAP AROUND PRECIP. CUTTER && .PREV DISCUSSION... 305 AM .DISCUSSION... FORECAST CHALLENGES WILL BE TEMPERATURES THROUGH MONDAY AND RAIN CHANCES TODAY AND AGAIN ON MONDAY. SHORTWAVE TROUGH CONTINUES TO DEEPEN/DIG SOUTH SOUTHEAST ACROSS EASTERN KS. WATER VAPOR IMAGERY SHOWS A VORTICITY MAX FORMING OVER NORTHWEST IA AND BEGINNING TO ROTATE SOUTH. THIS FEATURE WILL HELP MAINTAIN LAYERED CLOUDS ACROSS WESTERN IA AND NORTHWEST MO THIS MORNING. WILL NEED TO KEEP AN EYE ON RADAR TRENDS AS CURRENTLY HAVE A DRY FORECAST GOING FOR NORTHWEST MO TODAY. COOLING CLOUD TOPS FROM NORTHEAST OK INTO WEST CENTRAL AND CENTRAL MO INDICATE INCREASING LIFT THESE AREAS. RADAR ALSO SHOWS DEVELOPING ECHOES UNDERNEATH THIS ENHANCEMENT. 06Z ETA AND RUC QPF SUGGESTS THESE ECHOES WILL CONTINUE TO INCREASE IN INTENSITY SO HAVE ADJUSTED MORNING POPS FOR THESE AREAS ACCORDINGLY. CLEARING TREND WILL BE TIED TO PASSAGE OF 500MB TROUGH. SO NORTHWEST MO SHOULD SEE AFTERNOON SUN AND PART OF AFTERNOON FOR WEST CENTRAL MO. GOOD COLD AIR ADVECTION AND MID LEVEL COLD POOL WILL HOLD TEMPERATURES IN CHECK AND ONLY MINOR CHANGES MADE TO HIGHS FOR TODAY. NEXT UPPER SYSTEM DIVING SOUTHEAST FROM SASKATCHEWAN IS SPREADING HIGH CLOUDINESS INTO THE NORTHERN PLAINS. EXPECT THIS CLOUD COVER TO MOVE INTO CWA TONIGHT. BOUNDARY LAYER WINDS EXPECTED TO BACK IN ADVANCE OF THIS SHORTWAVE. THIS WILL CUT SHORT THE COLD AIR ADVECTION WITH WARM AIR ADVECTION MOVING BACK INTO THE REGION LATE TONIGHT. WARMING TOMORROW WILL BE MUTED TO SOME DEGREE BY THE HIGH CLOUDINESS AND GOOD MIXING ASSOCIATED WITH MODERATELY STRONG NORTHWEST WINDS. SATURDAY PRESENTS A BIT OF A TEMPERATURE CHALLENGE AS 850 MB TEMPERATURES ABOUT THE SAME AS FRIDAY BUT GOOD MID LEVEL WARM AIR ADVECTION EXPECTED TO GENERATE QUITE A BIT OF MID CLOUDS. THIS WILL NEGATIVELY IMPACT TEMPERATURES. CURRENT TEMPERATURE FORECAST HAS THIS IN HAND AND LOOKS REASONABLE. SOME NOTABLE CHANGES SHOWING UP IN THE 00Z GFS AND CANADIAN MODELS AS THEY ARE WETTER THAN PREVIOUS RUNS. BOTH MODELS HAVE AN ACTIVE SHORTWAVE COMING OUT OF THE SOUTHERN STREAM. SINCE TIMING WILL BE AN ISSUE AND LOCATION OF RAIN STILL IN QUESTION HAVE OPTED TO INSERT SLIGHT CHANCE WORDING STARTING SUNDAY NIGHT SPANNING INTO MONDAY NIGHT. IF MODELS SHOW SOME CONSISTENCY THEN IT WILL BE WORTH BUMPING UP RAIN CHANCES DURING THIS PERIOD. MJ && .PREV DISCUSSION... 830 PM... ALREADY HAVE DONE SOME MINOR TWEAKING TO THE FORECAST TO SCALE BACK PRECIPITATION CHANCES IN WESTERN AREAS TONIGHT...AND WILL LIKELY DO A LITTLE MORE AFTER HAVE HAD A CHANCE TO PERUSE SOME OF THE 00Z MODEL RUNS. WATCHING TRENDS ACROSS IOWA FOR LOW CLOUD DECK AND PRECIPITATION DEVELOPMENT WHICH SEEM TO BE POINTING MORE TOWARD EASTERN PORTIONS OF FORECAST AREA. THIS LINES UP BETTER WITH 18Z ETA LIFT ON THE 800 MB LEVEL. ALREADY HAVE ADJUSTED TAFS TO INCORPORATE THIS THINKING. PC && .PREV DISCUSSION... 256 PM... MAIN CONCERNS AT THIS TIME REVOLVE AROUND VORT MAX MOVING SOUTH TONIGHT AND SUBSEQUENT AFFECTS ON POPS AND TEMPS. NOT MUCH HAPPENING ALONG THE FRONT AT THE MOMENT. TEMPS HAVE STARTED TO DROP AS WINDS INCREASED. WHILE PRECIP HASN'T STARTED YET...THINK WILL DEVELOP OVERNIGHT. AS UPPER LEVEL LOW DEVELOPS OVER THE HIGH PLAINS TONIGHT...ISENTROPIC LIFT WILL ALSO DEVELOP ALONG THE FRONT. BOTH GFS/ETA SHOW INCREASING UPPER LEVEL DIVERGENCE OVERNIGHT AS JET MAX DEVELOPS IN SOUTHERN JET JUST SOUTH OF THE LOW. HAVE THEREFORE KEPT LIKELY POPS FOR TONIGHT...MAINLY AFTER MIDNIGHT. CLOUDS AND LIKELY PRECIP OVERNIGHT WILL KEEP TEMPS FROM FALLING TOO MUCH AND HAVE GONE FAIRLY CLOSE TO GUIDANCE (MODEL BLEND). COLD POOL IS PROGGED TO BE OVER SOUTHERN MISSOURI THURSDAY. HAVE LOWERED TEMPS EVERYWHERE WITH COOLEST READINGS OVER OUR CENTRAL MISSOURI COUNTIES. HAVE LOWERED POPS TO THE CHANCE CATEGORY FOR THURSDAY AS DOWNGLIDE DEVELOPS IN EARNEST BEHIND THE EXITING LOW. NEXT SHORTWAVE/COLD FRONT STILL EXPECTED ON FRIDAY. HAVE CONTINUED THE DRY FORECAST WITH VERY LITTLE MOISTURE TO WORK WITH. HAVE ALSO LOWERED EXPECTED HIGHS SEVERAL DEGREES FOR BOTH FRIDAY AND SATURDAY. FRONT LOOKS TO COME THROUGH QUICKER ON FRIDAY THAN PREVIOUSLY EXPECTED WITH COOLER TEMPS BEHIND IT FOR SATURDAY. THE SERIES OF SHORTWAVES MOVING THROUGH THE NORTHERN STREAM WILL CONTINUE INTO NEXT WEEK. HOWEVER IT LOOKS LIKE MOST OF THE EFFECTS WILL BE NORTH OF THE REGION. SO HAVE GONE WITH A DRY FORECAST AND NEAR NORMAL TEMPS. NRR && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 700 PM MDT THU OCT 14 2004 .DISCUSSION...CURRENT SURFACE MAP SHOWS HIGH PRESSURE BUILDING ACROSS MONTANA...WITH WINDS DECREASING ACROSS WESTERN SOUTH DAKOTA. WINDS NOW BELOW ADVISORY CRITERIA...SO WILL DROP ADVISORY A FEW HOURS EARLY. 18Z ETA/GFS ALONG WITH 21Z RUC CONTINUE TO SHOW STRONG FRONTOGENESIS ACROSS NORTHEAST WYOMING INTO SOUTHWEST SOUTH DAKOTA OVERNIGHT. PRECIPITATION COVERAGE CONTINUES TO INCREASE OVER MONTANA THIS EVENING. WATER VAPOR IMAGERY SHOWS SHORTWAVE DROPPING INTO WESTERN MONTANA...AND IT APPEARS TO BE A LITTLE STRONGER THAN EARLIER MODELS INDICATED. 00Z KUNR SOUNDING HAD FREEZING LEVEL AT 9200 FEET MSL...WITH WET BULB ZERO AT 6600 FEET MSL. FORECAST SOUNDINGS SHOW WET BULB/FREEZING LEVELS DROPPING THROUGH THE NIGHT. SHOULD END UP WITH A FEW INCHES OF SNOW IN THE BEAR LODGE MOUNTAINS AND BLACK HILLS OVERNIGHT. && .AVIATION...WINDS WILL CONTINUE TO DECREASE THROUGH THE EVENING. AS AREA OF PRECIPITATION EXPANDS ACROSS NORTHEAST WYOMING/SOUTHWEST SOUTH DAKOTA...CEILINGS WILL COME DOWN. CEILINGS LESS THAN 1000FT AGL LIKELY OVER NORTHEAST WYOMING AND THE BLACK HILLS AFTER 06Z. TEMPERATURES WILL BE COLD ENOUGH FOR SNOWFALL OVER THE BLACK HILLS AFTER MIDNIGHT. && .UNR...WATCHES/WARNINGS/ADVISORIES... .SD...NONE. .WY...NONE. $$ sd AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1050 AM CDT THU OCT 14 2004 .DISCUSSION... REMANT CLOUDINESS FROM UPR LOW PRESSURE AREA LINGERING IN FAR ERN CWA...AND CLOUDS INCREASING FM W WITH STG WAA BAND IN ADVANCE OF WMFNT SLIDING THRU WRN SD. IMPRESSIVE UPR WAVE IN WRN MANITOBA DIVING SEWRD TOWARD MN. ABR TO BIS RAOBS INDICATE PROCESS WHICH MUST OCCUR...SATURATING FROM MID LVLS. LOTS OF WET BULB ROOM...BUT INTENSITY OF PCPN SO FAR WITH GENERALLY TRACE AMTS UPSTREAM WL NOT MAKE THAT PROCESS TERRIBLY EFFICIENT...AND LKLY WL BE OVERWHELMED BY WARMING PROFILE...OTHERWISE...WOULD HAVE TO WORRY ABOUT A FEW FLURRIES ON LEADING EDGE OF PCPN IN NWRN CWA THIS MORNING. LEADING BAND SEEMS TO BE WEAKENING IN FAVOR OF MORE DYNAMICALLY SUPPORTED AREA FARTHER TO THE NW FM SERN ND TO CNTRL SD. FAIRLY DISTINCT BAND OF ISENTROPIC LIFT AT 300K TRANSLATES ACRS MOST OF CWA THRU REMAINDER OF SHORT TERM...BUT SIGNATURE FOR LIFT STARTS TO WKN THIS AFTN AS IT HEADS TOWARD SERN CWA. SATURATION BECOMES THE CONCERN FOR PCPN...AND BASED ON UPSTREAM AND RAOBS DO NOT INTERPRET AS A PROBLEM. OVERALL...FAIRLY DECENT CHANCE FOR MOST AREAS TO SEE SOMETHING FALLING FROM THE SKY TODAY...BUT THE MORE PRESSING ISSUE IS WHETHER IT WILL BE ENOUGH TO FORCE RAINFALL. COMFORT LEVEL ATTM IS TO KEEP TO ISOLD TO SCT LIGHT SHOWERS...FAVORING BETTER QG DYNAMICS WITH DIVING TROUGH NRN AND NERN CWA. WL BACK OFF SOMEWHAT ON TIMING...AS WELL AS INTENSITY...KEEPING FAR SE DRY THRU DAY. KNOCKED TMPS BACK SOME ACRS JAMES VALLEY AREAS FOR AFTN AND TRENDED TO SLOW CLIMB...AS WL HAVE MUCH OF HEATING TIME IN CLOUDS...AND WIND SHIFT TO WLY DOES NOT APPEAR AS IF IT WILL MAKE IT. FARTHER W...EXPECT WIND SHIFT TO PROGRESS ENOUGH TO ALLOW MORE MIXING OF WARM PUSH AS WARM FRONT APPROACHES IN LATE AFTN...AND KEPT MAXES HIGHER. ALSO RAISED TMPS SOMEWHAT IN E...AS WL HAVE APPRECIABLE SUNSHINE...AND TOOK TMPS CLOSER TOWARD 925 HPA MIXING VALUES BASED ON COOLER RUC/GFS. UPDATED GRIDDED DATA OUT...AND TEXT ZONES SOON. && .FSD...WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ CHAPMAN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI ISSUED BY NWS DES MOINES IA 1041 AM CDT THU OCT 14 2004 .DISCUSSION... PRIMARY CONCERNS FOR MRNG UPDATE WERE TEMP AND PCPN TRENDS. PCPN SHOWING LTL MOVMT ON RADAR MOSAIC WITH LTL TO NO SIGN OF CIGS LIFTING EITHER. 12Z RUC SHOWS MINIMAL HOPE OF CLRG EITHER WITH AT LEAST LYR OF MID CLDS IN PLACE...AND ST THRU MUCH OF THE DAY. LOW LVL RDG/COL BTWN WRN GRTLKS LOW AND APCHG NRN PLAINS SYS RMN TO THE W AS WELL...SO HAVE EXTENDED PCPN MENTION INTO EARLY AFTN AND RAISED POPS HIGHER INTO CHC CATEGORY DUE TO AREAL CVRG. THIS LED TO TRIMMING A FEW DEGREES OFF MAX TEMPS TOO. LOWERED TEMPS A FEW DEGREES IN SOME DAY 4-7 PERIODS TO BETTER BLEND WITH ADJACENT OFFICES. OTRW NO CHGS ATTM. && .ARX...WATCHES/WARNING/ADVISORIES... IA...NONE. WI...NONE. MN...NONE. && $$ SMALL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 455 AM EDT FRI OCT 15 2004 .DISCUSSION... MAIN FCST CONCERNS TURN FROM PCPN TRENDS TODAY TO PCPN TYPE/AMOUNTS SAT AND WINDS LATE SAT INTO SAT NIGHT. WV IMAGERY AND RUC ANALYSIS INDICATED A HIGH AMPLITUDE PATTERN WITH A RDG OVER THE WRN CONUS AND A TROF FROM WRN ONTARIO AND THE UPR MS VALLEY INTO THE LWR OH VALLEY AND THE SERN CONUS. A POTENT SHRTWV OVER KY/TN WAS LIFTING NE TOWARD THE SRN GRT LAKES. AT THE SFC...A TROF AND FRONTAL BNDRY EXTENDED FROM WRN ONTARIO INTO NW MN WHILE MAIN DEVELOPING LO WAS LOCATED OVER INDIANA. WEAK 700-600 FRONTOGENESIS AND 295K-300K ISENTROPIC LIFT SUPPORTED AN AREA OF RAIN FROM NRN LK MI ACRS THE E HLF OF UPR MI. TODAY...ETA/GFS/UKMET ARE IN GOOD AGREEMENT WITH THE SHRTWV AND ASSOCIATED LO PRES LIFTING NNE AND BRINGING DEEPENING SFC LOW (AROUND 988 MB) TO NE LK HURON OR GEORGIAN BAY BY 00Z/SAT. ADDITIONAL H25 JET ENERGY FROM THE PAC NW AND NRN PLAINS WILL HELP CLOSE OFF AN H5 LO INTO NW WI. THIS SHOULD ALLOW FOCUS OF 700-600 FRONTOGENETICAL FORCING AND ASSOCIATED ISENTROPIC LIFT OVER THE CNTRL AND ERN PORTIONS OF THE FORECAST AREA TO GRADUALLY SLIDE WESTWARD. SO...CATEGORICAL POPS OVER THE CWA FROM PREVIOUS FCST STILL LOOK ON TRACK ONCE COVERAGE PUSHES WEST BY THIS AFTERNOON. HOWEVER WITH GENERALLY WEAK UPWARD MOTION AND MOISTURE INFLOW...PCPN AMOUNTS/INTENSITY SHOULD REMAIN LIGHT WITH TOTALS GENERALLY BLO 0.25 INCH. TONIGHT...WHILE MDLS DISPLAY REASONABLE CONSENSUS WITH SFC LOW TRACK/TIMING WITH TREND TOWARD SLIGHTLY QUICKER PROGRESSION...FCST HEDGED TOWARD SLIGHTLY SLOWER ETA/UKMET WITH 980 MB LOW NE OF LAKE SUPERIOR (CYXZ) BY 12Z/SAT. DECENT DEEP LYR QVECTOR CONV TO THE NORTH OF THE DEEPENING H5 LOW OVER WI SHOULD SUSTAIN PERIOD OF PCPN OVER UPR MI. COLD ADVECTION AS THE LOW LIFTS TO THE NORTH SHOULD DRAW IN ENOUGH COLD AIR TO BRING MIX OF RAIN AND SNOW SHOWERS AND MAINLY -SHSN OVER HIGHER TERRAIN OF W UPR MI BTWN 06Z-12Z USING ETA/GFS BLEND 1305 1000-850 THICKNESS AS APPROXIMATE RAIN/SNOW LINE. SAT INTO SAT NIGHT...WHILE ISALLOBARIC COMPONENT IS LACKING FOR PUNCH OF HIGHER WINDS...VERY TIGHT GRADIENT WITH 15-17 MB PRES DIFFERENCE ACRS LAKE SUPERIOR AND CAA WITH SUBSTANTIAL DESTABILIZATION JUSTIFIES RETENTION OF HIGH WIND WATCH AND HIGH END GALE OUTLOOK FOR THE LAKE. THE ETA/GFS PROG 40-50 KT WITHIN THE MIXED LYR BTWN 21Z-03Z. WAVE HEIGHTS FCST TO NEAR 17 FT NEAR THE KEWEENAW AND ABV 20 FT OVER THE SE PORTION OF THE LAKE COULD ALSO CAUSE SOME COASTAL FLOODING IN SUSCEPTIBLE LOCATIONS. WRAP-AROUND PCPN CONTINUES WITH DEEP MOISTURE OVER THE AREA AND STRONG SFC-700 CYCLONIC FLOW ACRS THE REGION. VERY FAVORABLE SCENARIO SETS UP FOR LAKE ENHANCED PCPN (H8 TEMPS TO AROUND -6C GIVING LK-H8 DELTA T TO AROUND 14C) OVER W UPR MI LOCATIONS FAVORED BY WNW FLOW SUCH AS THE HIGHER TERRAIN OF THE KEWEENAW...ESPECIALLY FOR LOCATIONS NEAR M-38. WHILE ETA FCST SNDGS DEPICT SHALLOW ENOUGH WARM LYR FOR MAINLY SNOW...RELATIVELY WARM WATER(READINGS IN THE MID TO UPPER 40S) AND VERY STRONG WINDS MAY DISPLACE HEAVIER PCPN FAR INLAND OR PAST THE NARROWER PORTION OF THE KEWEENAW (AS IS TYPICAL IN EARLY SEASON LES) TO LIMIT SNOWFALL AMOUNTS. SO...EVEN THOUGH ETA QPF OUTPUT WOULD SUGGEST POTENTIAL FOR ADVY LVL SNOWFALL...AMOUNTS LIMITED TO 1-3 INCH RANGE FOR NOW...FOR INLAND HIGHER TERRAIN LOCATIONS AND INTO THE HURON MTS. AS THE MID LVL LOW LIFTS FAR ENOUGH NE TOWARD JAMES BAY BY LATE SAT NIGHT...QG FORCING WILL WEAKEN WITH DRIER 700-500 MB AIR MOVING INTO W LK SUPERIOR FOR PCPN TO DIMINISH OVER THE WEST. SUN INTO SUN NIGHT...LINGERING LAKE EFFECT/ENHANCED PCPN INTO THE ERN HLF OF THE CWA WILL GRADUALLY RECEDE TO THE WEST AS WEAK RDG PUSHES INTO THE WRN LAKES. SINCE ETA/GFS/UKMET SUGGEST PCPN ASSOCIATED WITH THE NEXT SHRTWV WILL REMAIN S OF UPR MI...POPS WERE TAPERED BACK AND MAY EVENTUALLY BE DROPPED IF MDLS REMAIN CONSISTENT WITH THIS TREND. && .MQT WATCHES/WARNINGS/ADVISORIES...HIGH WIND WATCH SAT/SAT EVNG && $$ JLB mi AREA FORECAST DISCUSSION...ADDED AVIATION/MARINE NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1055 AM EDT FRI OCT 15 2004 .UPDATE: WATER VAPOR LOOP SHOWS A VIGOROUS WAVE TRACKING NORTHEAST ACROSS THE OHIO VALLEY...AS THE TROUGH BEGINS TO TILT TO A NEGATIVE ORIENTATION. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 120-140KT SOUTHWESTERLY JET ACROSS THE SOUTHEAST CONUS...WHILE A 120KT NORTHWESTERLY JET WAS LOCATED ACROSS THE CENTRAL CONUS. 13Z SURFACE ANALYSIS PLACES A 991MB OCCLUDED LOW EAST OF DETROIT...WITH THE TRIPLE POINT LOCATED NEAR PITTSBURGH. A WARM/STATIONARY FRONT EXTENDS EAST-SOUTHEAST FROM THE TRIPLE POINT THROUGH THE CENTRAL DELMARVA...WHILE THE COLD FRONT WAS PUSHING ACROSS THE APPALACHIANS. A PRE-FRONTAL TROUGH WAS NEARING THE BLUE RIDGE. WATER VAPOR SHOWS MUCH MORE UPPER LEVEL MOISTURE THAN ANTICIPATED YESTERDAY ACROSS THE REGION. THIS IS INDICATIVE OF INCREASING VERTICAL VELOCITIES ON THE SYNOPTIC SCALE...AS THE LEFT EXIT REGION OF THE SOUTHEAST CONUS UPPER LEVEL JET APPROACHES. THIS WILL ALLOW WINDS AND WIND SHEAR THROUGH THE COLUMN TO INCREASE AS WELL AS PROVIDING FAVORABLE LIFT THIS AFTERNOON. TRACK OF THE MIDLEVEL SYSTEM TO THE NORTHEAST ACROSS THE OHIO VALLEY WILL SLOW ANY FRONTAL PASSAGE. FOR THIS REASON PREFER THE ETA OVER THE GFS FRONTAL TIMING. OUR EXTREME EASTERN FORECAST AREA WILL SEE PRECIPITATION DEVELOP AS THE UPPER LEVEL JET APPROACHES. MEANWHILE...PRECIPITATION TO FOCUS ON WILL BE ALONG THE COLD FRONT. HIGH AMOUNT OF DEEP LAYER SHEAR AND DYNAMICAL FORCING WILL MAINTAIN SUPPORT FOR A LINE OF DEEPER SHOWER ACTIVITY. SURFACE WINDS EVEN IN THE WARM SECTOR EAST OF THE BLUE RIDGE REMAIN BACKED DUE TO THE TRANSLATION OF THE SYSTEM AND RESULTANT PRESSURE FALLS TO OUR NORTHWEST. AS THE FRONT/LINE OF SHOWERS REACHES THE BLUE RIDGE...LOW LEVEL CONVERGENCE WILL DRAMATICALLY INCREASE WHEN COMPARED TO CURRENT POSITION OF THE FRONTAL BOUNDARY. THIS IS THE BEST CHANCE FOR CONVECTION TO DEEPEN. ANY DEEP SHOWER/CONVECTION ALONG THE FRONTAL BOUNDARY WILL HAVE THE ABILITY TO PROVIDE FOR GUSTY TO DAMAGING WINDS...AS THE FRONT TRANSLATES EAST OF THE BLUE RIDGE DURING THE EARLY AFTERNOON TO THE CHESAPEAKE BAY BY LATE AFTERNOON. 12Z RUC BUFKIT FORECAST SOUNDINGS INDICATE 0-1KM SHEAR OF 30-40KT THIS AFTERNOON EAST OF THE BLUE RIDGE. IF DEEP CONVECTION WERE TO DEVELOP...ENVIRONMENT IS FAVORABLE FOR A SEVERE WEATHER EPISODE WHICH MAY INCLUDE SHORT LIVED TORNADOES IN ADDITION TO GUSTY TO DAMAGING WINDS. WILL BE ISSUING A SPECIAL WEATHER STATEMENT TO DISCUSS THIS RISK. && .AVIATION: STRATO CU WILL CONTINUE TO DEVELOP DURING THE MIDDAY...WITH CEILINGS LOWERING WITH THE APPROACH OF THE FRONTAL BOUNDAY FROM THE WEST DURING THE MID AFTERNOON. WILL BE WATCHING RADAR TRENDS FOR POSSIBLE INCLUSION OF THUNDER IN TAFS. SOUTHERLY WINDS MAY GUST AHEAD OF THE FRONT...WITH WINDS EXPECTED TO INCREASE FROM THE WEST WITH THE FRONTAL PASSAGE THIS AFTERNOON. && .MARINE: SMALL CRAFT ADVISORY REMAINS IN EFFECT AS WINDS GUST FROM THE SOUTH AHEAD OF THE FRONTAL BOUNDARY. THIS BOUNDARY SHOULD PASS THROUGH THE WATERS THIS EVENING...MAINTAING GUSTY WINDS AS THEY VEER TO THE WEST. THUNDERSTORMS MAY DEVELOP ON THE COLD FRONT AS IT APPROACHES THE WATERS LATE THIS AFTERNOON...WINDS AND WAVES WILL BE HIGHER NEAR ANY THUNDERSTORMS. WATER LEVELS ARE A FOOT ABOVE NORMAL WITH THE SOUTHERLY GRADIENT FLOW. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY TIDAL POTOMAC RIVER AND CHESAPEAKE BAY. && $$ SHORT TERM/AVIATION/MARINE FORECASTER: ROGOWSKI md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 940 AM EDT FRI OCT 15 2004 .UPDATE... SENT OUT A QUICK UPDATE TO ADD MENTION OF THUNDER TO MUCH OF THE SOUTHERN AND EASTERN CWA. A FEW LIGHTNING STRIKES PICKED UP ACROSS LAKE ERIE/NORTHERN OHIO. 06Z ETA CROSS SECTIONS SHOW AN AREA OF WEAK SYMMETRIC INSTABILITY WITH THETA-E NEUTRAL TO DECREASING SLIGHTLY WITH HEIGHT...ALIGNED WITH STEEPER 700MB-500MB LAPSE RATES AHEAD OF THE DRY SLOT OF THE COMPACT SHORTWAVE OVER OHIO. THIS IS APPARENTLY ENOUGH TO GET STRONGER UPRIGHT CONVECTION WITH PRETTY GOOD UPWARD MOTION AHEAD OF THE SHORTWAVE. SHORTWAVE LIFTS ACROSS LAKE ERIE TODAY...WITH THE RUC TAKING IT A BIT FARTHER NORTH THAN THE ETA. CROSS SECTIONS/PLAN VIEWS SHOW THIS INSTABILITY WEAKENING A BIT ESPECIALLY AFTER THE 12Z-18Z TIME FRAME...BUT WITH AN AREA OF THETA-E LAPSE RATES NEAR ZERO LIFTING THROUGH THE THUMB. UPDATED TO ADD THUNDER GENERALLY SOUTHEAST OF BAD AXE TO HOWELL...ONLY CHANCE WORDING BASED ON DECREASING POTENTIAL THROUGH THE AFTERNOON. OTHERWISE REMAINDER OF THE FORECAST UNCHANGED...STICKING WITH CATEGORICAL POPS AND LITTLE TEMPERATURE REBOUND. && BRAVENDER .PREV DISCUSSION...325 AM EDT FRI OCT 15 2004 A TRUE SIGN OF AUTUMN WITH VIGOROUS UPPER LEVEL JET IN EXCESS OF 120KTS DIVING SOUTHEAST ACROSS THE PLAINS INTO THE LOWER MISSISSIPPI RIVER VALLEY THIS MORNING. DEEPENING UPPER LOW ROTATING INTO INDIANA IS EVIDENT WITH BAROCLINIC LEAF EVOLVING WITH EVEN SOME CONVECTION EMBEDDED WITHIN THE COLDER CLOUD TOPS (PER LIGHTNING DETECTION NETWORK) AND ON THE EDGE OF THE DRY SLOT...STEEPING LAPSE RATES. THIS WILL BE OUR MAIN WEATHER PLAYER FOR TODAY AND HEADING INTO THIS UPCOMING WEEKEND. H2O VAPOR LOOP/ANALYSIS REVEALS AMPLIFICATION OF THIS TROF HAS BECOME NEGATIVELY TILTED WITH SURFACE REFLECTIONS SHOWING RAPID PRESSURE FALLS ACROSS INDIANA. AREA RADARS BEGINNING TO FILL IN NICELY UPSTREAM AND ALL INDICATIONS ARE A VERY WET END TO THIS WEEK BUT QPF AMOUNTS ARE ROUGHLY LESS THAN HALF THE PREVIOUS RUNS. 00Z RAOBS UPSTREAM INDICATED PRECIPITABLE WATERS AROUND 0.75" SO AVAILABILITY WILL BE LOWER THAN PREVIOUSLY THOUGHT. MODELS STILL PAINT A NEAR METEOROLOGICAL BOMB BUT AT A SLOWER RATE THAN PREVIOUS RUNS. MODEL INITIALIZATION FAVORS THE GFS AND TO SPARE THE REDUNDANCY...PLEASE REFER TO THE PMDHMD. WIDESPREAD RAIN SHOWERS WILL ENCOMPASS US THIS MORNING FROM SOUTH TO NORTH AS MAIN UPPER DIFLUENCE AND DEEPENING SURFACE LOW MOVE ACROSS THE REGION. AFOREMENTIONED LIGHTNING ACTIVITY UPSTREAM APPEARS TO BE A COMBINATION FROM RAPID ACCELERATION IN THE VERTICAL FROM THIS DEEPENING CYCLONE AND STEEP LAPSE RATES FROM THE DRY SLOT. NEVERTHELESS, SHOWALTER INDICES WITHIN THIS ACTIVITY IS AROUND 1-2C WHICH IS PROGGED TO HEAD NORTH AND IMPACT OUR EASTERN COUNTIES. CROSS SECTIONS PER THE ETA/GFS DO HAVE SOME NEGATIVE EPV IN THE MID LEVELS WHICH IS UNDER THE DEFORMATION AXIS...YET LAPSE RATES ARE MORE IMPRESSIVE ACROSS THE OHIO VALLEY. THEREFORE, WE WILL KEEP THE MENTION OF THUNDER OUT OF THE GRIDS BUT WOULD NOT BE SURPRISED TO HEAR A RUMBLE OF THUNDER. OTHERWISE, DEFORMATION DYNAMICS WILL BECOME MORE DOMINANT THIS AFTERNOON AND EVENING WITH ISALLOBARIC COUPLET NOW FURTHER SOUTH (ALONG AND NORTH OF I69). THIS COULD BRING ABOUT A BRIEF GUST LATE TODAY BUT REMAIN BELOW ADVISORY CRITERIA. WITH THE CLOUD COVER AND PRECIP EXPECTED, TEMPERATURES WILL NOT RECOVER MUCH (MID 50S). LOW RAPIDLY DEEPENS THIS EVENING AS IT PULLS NORTH TOWARD JAMES BAY. NEEDLESS TO SAY, GRADIENT TIGHTENS AS MAIN UPPER LOW DIVES SOUTH ACROSS THE CENTRAL GREAT LAKES. THIS WILL ALLOW FOR THE STRONG COLD ADVECTION TO SPREAD INTO THE REGION OVERNIGHT WITH 850MB TEMPS DROPPING BELOW 0C. RAINFALL WILL LIKELY TAPER OFF UNTIL FULL WRAP AROUND AND LAKE CONTRIBUTION OCCURS AFTER 06Z. TEMPERATURES WILL SETTLE BACK INTO THE LOWER 40S WITH WIND CHILLS HOVERING NEAR THE FREEZING MARK! SATURDAY CAN BE SUMMARIZED AS CHILLY AND DAMP. WITH LAKE-AIR DELTA T'S NEAR 20C AND IMPRESSIVE MID LEVEL LAPSE RATES (NOT TO MENTION NEAR -30C AT 500MB), WE WILL INCREASE OUR COVERAGE AND POPS TO LIKELY FOR RAIN SHOWERS AND KEEP TEMPS AROUND 50F! STILL SOME CONCERN FOR WIND ADVISORY HEADLINES WITH CENTER OF SURFACE PRESSURE RISE COMING ACROSS DURING THE EARLY AFTERNOON. FORECAST SOUNDINGS FROM THE GFS WHEN COMPARED TO PREVIOUS RUNS, SUGGEST MID LEVEL WINDS ARE DECREASING WITH CURRENT PROGS TAPPING INTO 35-40KTS...AND LATER IN THE DAY. WE WILL STILL HIGHLIGHT WITHIN THE HWO AND WE WILL HOLD BACK ON HOISTING GALE WARNINGS (BEYOND 24 HOURS FROM THIS POINT) FOR THE OPEN AND NEARSHORE WATERS. A VERY CHILLY SATURDAY NIGHT AS MAIN LOW BECOMES FURTHER REMOVED FROM THE PICTURE YET DEEP CYCLONIC MOISTURE WILL REMAIN...MAINLY BEFORE MIDNIGHT. WE WILL RETAIN OUR CURRENT CHANCE GRIDS AT THIS TIME. IN ADDITION, 1000-850 THICKNESSES AND WET BULB PROFILES STILL POINT TO SOME OF THAT WHITE MATERIAL TO FALL ACROSS THE TRI-CITIES REGION AND PERHAPS INTO THE THUMB (BUT WILL LIKELY BE A BIT WARMER WITH CONTRIBUTION FROM SAGINAW BAY). BREAKS IN THE CLOUD COVER AND A REBOUND IN THE TEMPS SHOULD MAKE FOR A BETTER LATER HALF OF THE WEEKEND AS SUBSIDENCE OVERSPREADS THE REGION. HOWEVER, FORECAST MIXING LAYER HEIGHTS AND DISAGREEMENTS WITH UPSTREAM WARM ADVECTION COULD STILL HOLD BACK TEMPS SOMEWHAT. BUT WE WILL HOLD ONTO OUR DRY FORECAST. THESE DISAGREEMENTS CONTINUE INTO EARLY NEXT WEEK WITH THE POTENTIAL FOR AN OVER-RUNNING EVENT SETTING UP PER THE ECMWF/UKMET/CANADIAN-GLOBAL AND GFS. DPROG/DT AT THIS TIME FRAME SHOWS CONSIDERABLE UNCERTAINTY AND WE ARE RELUCTANT TO MAKE SIGNIFICANT CHANGES TO THE FORECAST AT THIS TIME.. && .DTX WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY IN EFFECT...TONIGHT THRU SUNDAY...FOR ALL OF THE NEARSHORE WATERS. && $$ BGM EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1010 AM EDT FRI OCT 15 2004 .UPDATE... LATEST RADAR MOSAIC DOES NOT SHOW A LOT OF RAIN NEAR THE REGION THIS MORNING. HOWEVER, A BAND OF SHOWERS CONTINUES TO MOVE NORTHEASTWARD EXTENDING ACROSS CENTRAL PA AND DOWN INTO THE SOUTHERN DELMARVA. VISIBLE SATELLITE IMAGERY EVEN SHOWING SOME THIN SPOTS IN THE OVERCAST (SOME SUNSHINE PEAKING OUT HERE AT THE OFFICE), ESPECIALLY ACROSS CENTRAL AND SOUTHERN NEW JERSEY, AND INTO DELAWARE. THE THINKING THIS MORNING IS THAT THESE BREAKS WILL NOT LAST TO LONG AS MORE CLOUD COVER MOVES IN FROM THE SOUTHWEST. THE MAIN UPPER-LEVEL LOW AND SURFACE WAVE IS ACROSS OHIO WITH AN ATTENDING COLD FRONT APPROACHING WESTERN PENNSYLVANIA AT THIS TIME. AS THIS FEATURE LIFTS TO THE NORTHEAST THIS AFTERNOON, ADDITIONAL LIFT WILL OVERSPREAD OUR CWA WHICH WILL ALLOW FOR SHOWERS TO DEVELOP. THE GREATEST HEIGHT FALLS/INCREASING LARGE SCALE ASCENT APPEAR TO BE CENTERED TO OUR SOUTH, WHICH SHOULD KEEP THE STRONGEST CONVECTION SOUTH OF OUR AREA. AREA 12Z SOUNDINGS DO INDICATE SOME LOW-LEVEL SHEAR, WITH STRONGER WINDS UP AROUND 850 MB. MAIN CONCERN IS THAT ANY CONVECTION THAT FORMS MAY BE ABLE TO TAP SOME OF THAT WIND, ESPECIALLY CLOSER TO FROPA. IT APPEARS THAT ANY WIND GUSTS WILL REMAIN BELOW SEVERE LEVELS WITH ANY ISOLATED THUNDERSTORMS THIS AFTERNOON. RADAR TRENDS WILL BE MONITORED THIS AFTERNOON. GIVEN THE LATEST OBS, RADAR AND SATELLITE IMAGERY, ALONG WITH THE RUC GUIDANCE, AN UPDATE WILL BE ISSUED TO REWORD THE FORECAST AS SHOWERS. WE WILL KEEP THE MENTION OF THUNDER FOR THIS AFTERNOON AS THE FRONT GETS CLOSER AND CROSSES THE REGION LATER IN THE DAY. HOURLY TEMPS AND DEWPOINTS WILL ALSO BE ADJUSTED TO MATCH CURRENT CONDITIONS. NOT MUCH CHANGE TO THE MARINE FORECAST, OTHER THAN MINOR TWEAKS TO THE WINDS AND WEATHER. MINOR TIDAL FLOODING WAS REPORTED THIS MORNING IN MONMOUTH COUNTY WITH WATER ON SOME ROADWAYS. && .PREVIOUS DISCUSSION... 345 AM EDT FRI OCT 15 2004 .SHORT TERM (TODAY THROUGH SATURDAY NIGHT)... RAIN SHOULD DEVELOP OVER THE REGION DURING THE MORNING AS ADDITIONAL MOISTURE MOVES OVER THE AREA FROM THE SOUTHEASTERN CONUS. THE UPPER LOW REMAINS OVER THE OHIO VALLEY AND A COLD FRONT WILL MOVE THROUGH THE REGION DURING THE LATE AFTERNOON HOURS. AN AREA OF LOW PRESSURE WILL MOVE ALONG THE COLD FRONT AFTER IT HAS PASSED EAST OF THE REGION AND IT WILL DEEPEN AS IT MOVES INTO NEW ENGLAND. IT LOOKS LIKE THE BEST RAIN CHANCES WILL COME THIS AFTERNOON AS THE COLD FRONT MOVES THROUGH AND MOISTURE MOVES IN FROM THE SOUTH. THE STEADIEST RAIN SHOULD END THROUGH THE EVENING HOURS FROM SOUTH TO NORTH. AT THIS TIME...GENERALLY 0.25 TO 0.50 INCHES ARE EXPECTED OVER THE AREA...WITH SOME LOCALLY HIGHER AMOUNTS. WINDS WILL GUST WITH THE COLD FRONT PASSAGE AND WILL REMAIN IN THE 20 TO 30 MPH RANGE THROUGH SATURDAY DUE TO THE PRESSURE GRADIENT BETWEEN THE LOW PRESSURE TO THE NORTH AND HIGHER PRESSURE TO THE SOUTH. THERE COULD BE A PASSING COLD ADVECTION SHOWER DURING THE DAY ON SATURDAY...BUT OVERALL...CONDITIONS SHOULD BE IMPROVING. && .LONG TERM (SUNDAY THROUGH THURSDAY)... SUNDAY AND MOST OF MONDAY LOOK TO BE DRY AT THIS POINT...WITH HIGH PRESSURING STRENGTHENING OVER THE SOUTHEASTERN CONUS AND BUILDING NORTHWARD. A WARM FRONT WILL APPROACH THE AREA LATE MONDAY INTO TUESDAY...AHEAD OF A LOW MOVING IN FROM THE WEST. ANOTHER CHANCE OF SOME RAIN...WITH WARMING TEMPS ARE IN STORE. CURRENT MODEL DATA INDICATE THAT FRONT WILL CLEAR THE AREA BY WEDNESDAY. && .MARINE... I WILL BE GOING WITH SCA ALL WATERS THIS FCST. ALTHOUGH WINDS AND SEAS CURRENT ARE BELOW SCA CRITERIA...GUSTINESS SHOULD INCREASE THIS EVENING WITH SUSTAINED WINDS INCREASING LATER TONIGHT AS THE COLD AIR MOVES IN FROM THE WEST. I HELD OFF ON ANY GALES SINCE THE LATEST GUIDANCE SHOWS THE GRADIENT NOT AS STRONG AS THE PREVIOUS RUNS. CONSIDERING THE TRACK OF THE MAIN LOW IS SO FAR TO THE WEST, THIS LOOKS REASONABLE FOR NOW. THE GRADIENT GRADUALLY RELAXES SUNDAY AND EARLY NEXT WEEK ALLOWING WINDS TO SLOWLY DIMINISH. A WARM FRONT MOVES THROUGH FROM THE S LATE MON NIGHT/TUE BUT WINDS ASSOCIATED WITH IT DONT LOOK STRONG ENOUGH TO JUSTIFY ANY HEADLINES. && .AVIATION... SOME LIGHT FOG HAS LOWERED VSBY TO 1-3 NM WHILE OTHER AREAS ARE P6SM. RDG BRIEFLY WENT BELOW 1 NM. WITH THE CLOUDS COMING IN FROM THE SW...AND RAIN DEVELOPING THE FOG SHOULD GENERALLY REMAIN WITH VSBYS BECOMING WIDESPREAD 2-5NM WITH THE RAIN AND LIGHT FOG ASSOCIATED WITH IT. CIGS ARE SPOTTY BELOW 1 THSD FT WITH MOST AREAS 1-3K FT. THESE CONDITIONS SHOULD CONTINUE EVEN WITH THE RAIN. THE COLD FRONT IS FORECAST TO MOVE THROUGH FROM THE SW SHIFTING WINDS TO THE W BETWEEN 21-00Z. CB IS IN THE FCST, BUT CONFIDENCE IS NOT HIGH ENOUGH TO CARRY ANY GROUPS FOR ACTUAL TSRA. && .TIDAL DISCUSSION... GUIDANCE SUGGESTS SOME MINOR TIDAL FLOODING AROUND HIGH TIDES ALTHOUGH IT IS MARGINAL. THE CURRENT SPS WILL BE CONTINUED AND INDICATE THIS. && .HYDROLOGY... THE LATEST MODEL DATA SUPPORTS A GENERAL RAINFALL OF 0.25 TO 0.50 INCHES WITH LOCALLY HIGHER AMOUNTS ACROSS THE REGION TODAY. THERE COULD BE AN ISOLATED THUNDERSTORM LATE THIS AFTERNOON INTO THIS EVENING WITH THE COLD FRONT. THESE RAINFALL AMOUNTS ARE NOT EXPECTED TO CAUSE FLOODING PROBLEMS. $$ .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. MD...NONE. DE...NONE. MARINE...SMALL CRAFT ADVISORY ZONES ANZ450>455 ANZ430>431. && $$ UPDATE...GORSE SHORT TERM/LONG TERM...LSN AVIATION/MARINE/TIDAL DISCUSSION...RNS pa AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1002 AM CDT FRI OCT 15 2004 .DISCUSSION... MAIN TROUGH CURRENTLY LIFTING THRU MN WITH 115 KT JET DIGGING ON BACK SIDE THROUGH THE PLAINS. SECONDARY ENERGY ROTATING INTO ERN MT WITH BREAK IN JET CORE...ENHANCING MID AND HIGH CLDS INTO WRN SD. A FEW LIGHT SHRA ALG LEADING EDGE OF CLOUDS ON KFSD 88D SLIDING JUST EAST OF AREA...BUT FAR FROM IMPRESSIVE. SEVERAL FAIRLY MINOR CONCERNS TODAY...BUT WL FOCUS ON TMPS AND WNDS. ETA CONTINUES TO RUN ABOUT 2-3C WARMER AT LOWER LEVEL TEMPERATURES COMPARED TO RUC/GFS...AND FOR NOW WL FAVOR SLIGHTLY COOLER PICTURE ON RUC FOR MIXED TMPS TDA. DID END UP RAISING A FEW TMPS ACRS MORE SUNNY PARTS OF NW IA...WHERE TMPS LKLY TO REACH MIDDAY MAX AHEAD OF CLDS. FCST WINDS IN MIXED LYR SEEM TO GRAVITATE TO AROUND 35 KTS MAX...SO WOULD SUGGEST STEER CLEAR OF WIND ADVISORY...WITH A FEW GUSTS TO 35 MPH OR SO AS MIXED LAYER DEEPENS A BIT INTO AFTERNOON. UPDATED FCST EARLIER TO ACCOUNT FOR MORE RAPID WIND INCREASE...AND MORE SOLID CLOUD SHIELD FOR A TIME MIDDAY...ESPECIALLY N AND NE. SHAVED A DEGREE OF TWO OFF FAR NRN CWA AS WELL. DID NOT COMPLETELY REASSESS PRECIP TEMPORAL DISTRIBUTION WITH FORMER UPDATE...AND IN FACE OF STRENGTHENING LARGE SCALE SUBSIDENCE FOR AFTERNOON...WL LKLY REFINE LATER MORNING TO REMOVE OR DROP TO A FEW SPRINKLES IN SW MN...WHERE FCST RAOBS STILL INDICATING A VERY SMALL TOUCH OF LOW TOPPED POSITIVE AREA. && .FSD...WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ CHAPMAN sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WAKEFIELD VA 1025 AM EDT FRI OCT 15 2004 .SHORT TERM (REST OF TODAY)... REGIONAL RADARS SHOW LARGE AREA PCPN WORKING NE THRU ERN CAROLINAS AHEAD VIGOROUS SHORT WAVE MOVING THRU THE DEEP SOUTH. OTHER THAN LTST RUC RUN...MODELS SOMEWHAT UNDERESTIMATING AMOUNT AND INTENSITY OF THE WESTERN EDGE OF THIS PCPN BAND SO WILL TIME PCPN ENDING BASED ON CURRENT TRENDS/LTST RUC. WITH THIS IN MIND...EASTERN 2/3RDS FCST AREA (BASICALLY EAST OF I95) LIKELY TO SEE PERIODS OF STEADIER RAIN THEN ENDING EARLY AFTN INLAND AREAS AND MID/LATE AFTN ENDING TIMES FOR CSTL REGIONS. SEVERE TS THREAT IS LOW WITH CLOUDS/COOLING RAINS HAVING LIMITED INSTABILITY AND GIVEN THE MEAGER WIND SHEAR PROFILES. LTG ACTIVITY HAS BEEN CONFINED TO OFFSHORE THUS FAR BUT EXPECT SOME LTG/DEEPER CONVECTION WL DEVELOP OVR ERN CAROLINAS BY MIDDAY AS JET DYNAMICS GET BETTER ORGANIZED AHEAD OF APPROACHING IMPRESSIVE SHORT WAVE. SO WILL KEEP TS MENTION GOING WHILE MINIMIZING THE SVR THREAT. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 310 AM EDT FRI OCT 15 2004 SHORT TERM (TODAY AND TONITE)...FA PROGGED BTWN MAIN ENGY LIFTG N INTO PA AND CONVECTIVE LINE OF PCPN FROM CAROLINAS ON S. UPSHOT WILL BE A PRD OF PCPN SHWRS TDY...ENDING W-E THIS AFTRN AS DRY SLOT MOVES E. AS FRNTL BNDRY CROSSES FA...INCRG LL JET COMBINED WITH BAND OF THETHA E & LI'S AOB 0...SHUD MAKE AIRMASS UNSTABLE ENUF FOR SCT TSRA. LESS THREAT W OF I95...GREATEST ALONG CSTL SCTNS. XPCT TO SEE A LINE OF TSRA DVLP THEN MOVG E ACROSS FA WHICH SHUD INTENSIFY (SPCLLY IF ANY HTNG OCCURS) AS THEY APPROACH THE CHES BAY. ANY TSRA WILL HAVE PTNTL TO PRODUCE GUSTY WNDS...BUT SVR THREAT APPEARS MINIMAL ATTM. MODELS SUGGESTING THAT PCPN MAY TAKE UNTIL ARND 00Z TO EXIT OFF LWR MD ERN SHORE...SO HAVE INCLUDED A 20 POP THERE FOR ERLY EVE. OTW... DRYER AIR RPDLY MOVES IN CLRG SKIES OUT FOR TONITE ALONG WITH INCRG WND SPEEDS AS CAA SETS IN. LONG TERM (SATURDAY THROUGH THURSDAY)...LOW PRES CONTS TO INTENSIFY AS IT LIFTS N INTO SRN CANADA BY SAT NITE. PRS GRDNT ARND SYSTM RESULTS IN RTHR BREEZY TO WNDY DAY (AVG 15-25 MPH WITH HIGHER GUSTS). GFS INDCTG PIECE OF NRGY SPINNING ARND UPR LVL LOW PRODUCES SCT AFTRN SHWRS N OF FA WHICH CUD ROTATE INTO LWR MD ERN SHORE AFTR 18Z. THUS WILL ADD A 20 POPS TO THAT AREA IN GRIDS. OTW...JUST AFTRN CU DVLPS AS STRNG DOWNSLOPING OFFSETS ANY ADDTNL PCPN COVERAGE. HIGH PRS BUILDS INTO RGN SUN INTO ERLY MON ALONG WITH A WRMG TREND. MODELS DIVERGE BY LATE MON AS ETA GENERATES SOME QPF AHEAD OF ADVANCING WRM FRNT. GFS FRTHR W WITH BNDRY AND DRYER. THUS HAVE ADDED 20 POPS MON AFTRN TO GRIDS ACROSS NRN AREAS. ANTHR CDFRNT PROGGED ACROSS FA TUE FOLLOWED BY COOLER CNDTNS BY MID WEEK. AVIATION...VFR CNDTNS GNRLY XPCTD. HOWEVER...LCL MVFR THRU 18Z IVOF RIC AND THRU 00Z CSTL TAF SITES DUE TO SCT SHRA/TSRA. W WNDS BEGIN TO INCRS AFTR 06Z TONITE. MARINE...SCA ALL AREAS. HAVE LOWERED GALE THREAT TONITE THINKING THAT STRNGST WNDS ON SAT WILL HOLD JUST BLO GALE CRITERIA. CUD SEE AN OCNL GUST TO 35 KT THOUGH. FIRE WEATHER...WILL HIGHLIGHT FWF THIS AM FOR GUSTY WNDS LATE TONITE AND SAT. MIN RH VALUES SHUD DROP TO BTWN 30-40% SAT AFTRN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...SMALL CRAFT ADVISORY FOR ZONE NCZ102 THROUGH SATURDAY. VA...NONE. MARINE...SMALL CRAFT ADVISORY FOR ZONES ANZ630>632-656-658-633 THROUGH SATURDAY. ...SMALL CRAFT ADVISORY FOR ZONES ANZ650-652-654 THROUGH SUNDAY. && $$ SHORT TERM (UPDATE)...CULLEN va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 955 AM CDT FRI OCT 15 2004 .UPDATE...TODAY RADAR/SATELLITE DATA SHOWING AN AREA OF SHOWERS OVER CENTRAL MINNESOTA. THIS AREA IS MOVING SOUTHEAST...AND WILL ENTER THE FORECAST AREA LATE THIS MORNING. THIS PRECIPITATION IS IN RESPONSE TO MID LEVEL FRONTOGENESIS...AS SHOWN BY THE LATEST 12Z RUC/ETA RUNS. THIS AFTERNOON...AN AREA OF UPPER LEVEL POTENTIAL VORTICITY ADVECTION WILL MOVE OVER THE SAME PORTION OF THE FORECAST AREA...AS DEPICTED BY THE RUC/ETA SOLUTIONS. THEREFORE...HAVE INCREASED CLOUDS/PRECIPITATION CHANCES TO INCORPORATE THIS LATEST THINKING. KRC && .PREVIOUS DISCUSSION... SHORT TERM...THROUGH SUNDAY MAIN FORECAST PROBLEM IS WITH THE PRECIPITATION CHANCES THROUGH THE WEEKEND. SURFACE ANALYSIS EARLY THIS MORNING INDICATED LOW PRESSURE NEAR KIND AND ANOTHER ELONGATED AREA OF LOW PRESSURE OVER WESTERN MINNESOTA. 00Z MODEL RUNS OF THE GFS AND ETA ARE PRESENTING SOMEWHAT SIMILAR SOLUTIONS THROUGH SUNDAY. CUT OFF LOW OVER THE OHIO VALLEY WILL LIFT NORTHEAST INTO THE EASTERN GREAT LAKES TODAY AS ANOTHER CUT OFF LOW MOVES OUT OF SOUTHERN CANADA INTO THE UPPER MIDWEST. BOTH MODELS SHOW A SHORT WAVE TROUGH WITH THE UPPER LEVEL LOW BUT THE GFS INDICATES MORE PV ADVECTION AND PRODUCES MORE LIFT AND PRECIPITATION THAN THE ETA. WITH BOTH MODELS SHOWING 500 MB TEMPERATURES COOLING DURING THE DAY WITH THE APPROACH OF THE UPPER LEVEL AND LOW LEVEL CYCLONIC FLOW...SEEMS REASONABLE TO EXPECT SOME LIGHT QPF TODAY. ONLY ADJUSTMENT TO PREVIOUS FORECAST WAS TO LIMIT THE POPS FOR THE MORNING HOURS TO AREAS WEST OF THE MISSISSIPPI RIVER. CYCLONIC FLOW ALOFT WILL CONTINUE TONIGHT ALONG WITH SOME WEAK UPGLIDE ON THE 290K ISENTROPIC SURFACE WHICH SHOULD BE ENOUGH TO KEEP SOME LIGHT PRECIPITATION GOING. COME CONCERNS DEVELOP ABOUT PRECIPITATION TYPE. ETA BUFKIT DATA SHOWS ENOUGH COLD AIR IN THE LOW LEVELS MOVES IN TO CHANGE OVER TO ALL LIGHT SNOW IN SOUTHEAST MINNESOTA AROUND 06Z. COLD AIR THEN GRADUALLY SHIFTS EAST WITH THE BUFKIT DATA NOT SHOWING KDBQ AND KAUW NOT CHANGING OVER TO SNOW UNTIL VERY LATE TONIGHT. CURRENT DATABASE INDICATES A MIX OF RAIN AND SNOW FOR ENTIRE AREA AFTER MIDNIGHT. THIS MAY BE A LITTLE FAST FOR AREAS EAST OF THE MISSISSIPPI RIVER AND DAY SHIFT MAY HAVE TO TAKE A CLOSER LOOK AT THIS. A WEAK SURFACE RIDGE EXPECTED TO BUILD OVER THE AREA FOR SATURDAY AND SATURDAY NIGHT SHUTTING OFF ANY LINGERING PRECIPITATION. NEXT SYSTEM EXPECTED TO MOVE EAST OF THE ROCKIES SUNDAY SETTING UP A WARM AIR ADVECTION PATTERN OVER THE AREA. GOOD UPGLIDE DEVELOPS ON THE 290K ISENTROPIC SURFACE WITH UP TO 5-6 UBAR/S BY LATE SUNDAY AFTERNOON. CONDENSATION PRESSURE DEFICITS LOWER AS WELL TO SUPPORT THE DEVELOPMENT OF SOME RAIN. BOTH MODELS SUGGEST ANY RAIN CHANCE WOULD HOLD OFF UNTIL THE AFTERNOON...SO WENT AHEAD AND REMOVED THE POPS FOR SUNDAY MORNING. LONG TERM...SUNDAY NIGHT THROUGH THURSDAY CURRENT DATABASE INDICATES A DRY FORECAST FOR MONDAY. HOWEVER...THE 00Z GFS DEVELOPS A SURFACE LOW IN THE LOWER PLAINS AND TAKES THIS NORTHEAST TOWARD NORTHERN INDIANA THROWING SOME PRECIPITATION ACROSS MAINLY THE SOUTHERN SECTIONS OF THE FORECAST AREA. OPTED TO LEAVE THE FORECAST DRY FOR NOW...BUT IF CURRENT TRENDS CONTINUE... LATER SHIFTS MAY HAVE TO ADD IN SOME POPS. 04 && .ARX...WATCHES/WARNING/ADVISORIES... IA...NONE. WI...NONE. MN...NONE. && $$ KRC wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 300 PM EDT FRI OCT 15 2004 .DISCUSSION... TONIGHT...COLD FRONT SLICING ACROSS THE AREA PRECEDED BY A DIMINISHING LINE OF FAST MOVING SHOWERS IN SOUTHERN SECTIONS. CLOUD BAND WILL SLIDE SOUTHEAST OF THE AREA THIS EVENING. MAY HAVE TO INCLUDE A SMALL EARLY EVENING POP FOR SOUTHEAST SECTIONS...MAINLY MARTIN COUNTY...BUT OTHERWISE COLD AND DRY AIR ADVECTION UNDERWAY IN NORTHERN SECTIONS WILL SWEEP ACROSS THE ENTIRE AREA. WEAK SURFACE RIDGE BUILDING ACROSS THE AREA WILL PROVIDE A PERIOD OF RADIATIONAL COOLING IN THE EARLY MORNING. THIS WILL RESULT IN A MUCH COOLER TEMPERATURES WITH MAV GUIDANCE SHOWING THE COMBINATION OF COLD AIR ADVECTION AND RADIATIONAL COOLING RESULTING IN RATHER UNIFORM LOWER 50S AREAWIDE. THIS WOULD BE IN LINE TO SET SOME RECORD LOWS IN SOUTHERN SECTIONS (VERO BEACH RECORD LOW FOR 10/16 IS 56). SAT-SUN... A SFC HIGH PRESSURE CELL OVER THE WRN GOMEX WILL SLIDE ACROSS THE FL PENINSULA THRU SATURDAY NIGHT UNDER THE INFLUENCE OF A STRONG NWRLY FLOW IN THE H85-H30 LYR. THE RIDGE WILL BE ACCOMPANIED BY A VERY DRY AIRMASS...LATEST RUC80 ANALYSIS INDICATES H100-H50 MEAN RH VALUES AOB 40% OVER THE U.S. GULF COAST FROM BROWNSVILLE, TX TO CEDAR KEY, FL. VERY LIGHT WINDS AND DRY AIR SHOULD ALLOW FOR DECENT RADIATIONAL COOLING CONDITIONS SAT NIGHT...WILL UNDERCUT MOS TEMPS BY A FEW DEGREES. WILL SEE A RETURN FLOW DEVELOP ON SUN AS THE RIDGE AXIS AND ITS ACCOMPANYING DRY AIR PUSHES INTO THE SW ATLC. TEMPS WILL RECOVER TO NEAR CLIMO LVLS...BUT THE AIR WILL BE TOO DRY TO SUPPORT ANY PRECIP. MON-FRI... DRY WX PATTERN IN STORE FOR NEXT WEEK AS MID RANGE MODELS INDICATES AN H85-H50 ANTICYCLONE MERGING WITH THE SFC RIDGE OVER THE WRN ATLC. THE COMBINED RIDGE WILL DEEPEN THE EASTERLY FLOW THROUGH THE H50 LYR...BUT THE EASTERLIES WILL TAP ONLY TAP THE AFOREMENTIONED DRY AIR MASS. THE LOW LVL AIR GRADUALLY WILL MODIFY OVER THE ATLC...BUT CONDITIONS ALOFT WILL BE TOO DRY TO ALLOW ANYTHING MORE THAN ISOLD LOW-TOPPED COASTAL SHRAS TO DEVELOP. EVEN THEN...POPS ARE TOO SMALL TO INCLUDE IN THE FCST ATTM. && .MARINE... SCA WINDS WILL REMAIN IN PLACE OVERNIGHT AS THE WIND SURGE BEHIND THE FRONT PUSHES ACROSS THE AREA. WHILE THE SEAS WILL REMAIN AOB 5FT...THE OFFSHORE FLOW WILL GENERATE VERY SHORT PD SEAS...GENERALLY BLO 5SEC. CONDITIONS WILL IMPROVE BY SAT AFTN AS RIDGE SLIDES ACROSS THE PENINSULA AND INTO THE ATLC...WITH AN ONSHORE FLOW AOB 15KTS DEVELOPING BY SUN AFTN. && .FIRE WEATHER... DRIER AIR BEHIND THE FRONT SHOULD ALLOW AFTERNOON LOW RH VALUES TO DROP INTO THE 40-45 PERCENT RANGE NEXT FEW DAYS. && .PRELIMINARY POINT TEMPS/POPS... DAB 52 78 57 82 / 0 0 0 0 MCO 52 80 58 85 / 0 0 0 0 MLB 52 79 58 83 / 0 0 0 0 VRB 52 79 57 83 / 0 0 0 0 && .MLB WATCHES/WARNINGS/ADVISORIES... ...SMALL CRAFT ADVISORY FLAGLER BEACH TO JUPITER INLET. ...FLOOD WARNING MIDDLE ST JOHNS RIVER BASIN. && $$ SHORT TERM...LASCODY LONG TERM...BRAGAW fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 137 PM MDT FRI OCT 15 2004 .SHORT TERM...(TONIGHT THROUGH MONDAY) TONIGHT/SATURDAY...MODELS HANDLING TODAYS LIGHT PRECIPITATION EVENT WELL...WITH SUBTLE SHORTWAVE IN NORTHWEST FLOW/CONVERGENCE AT 700 MB/FRONTOGENESIS COMBINING TO PRODUCE THE LIFT. FORCING SHIFTS SOUTH AND WEAKENS THIS EVENING...AND WILL MONITOR LAST MINUTE RADAR TRENDS FOR EVENING PRECIP CHANCES. SURFACE RIDGE SETTLES ALONG THE KANSAS COLORADO STATE LINE BY 09Z. DESPITE A BRIEF PERIOD OF LIGHT WINDS...PLENTIFUL MID/HIGH CLOUDS WILL NOT ALLOW FOR MUCH RADIATIONAL COOLING...SO DO NOT EXPECT TO FALL BELOW GUIDANCE TEMPERATURES. RUCII SHOWING STREAM OF STRATUS COMING UP INTO EASTERN COLORADO SATURDAY MORNING IN RETURN FLOW...AND THIS MAY HAMPER MORNING WARM UP. HOWEVER BREEZY SOUTH WINDS BY EARLY AFTERNOON WILL ALLOW A NICE REBOUND IN TEMPERATURES...WARMEST IN THE WEST WITH SLIGHT DOWNSLOPE COMPONENT TO THE SURFACE WIND. SUNDAY/MONDAY...DAMPENING SHORTWAVE WILL APPROACH THE AREA FROM THE SOUTHWEST SUNDAY AFTERNOON. BEST LIFT CENTERED AROUND 00Z/18...HOWEVER LOW LEVEL MOISTURE SCARCE...AND WITH WESTERLY LOW LEVEL WINDS THROUGH SUNDAY NIGHT WILL KEEP DRY FORECAST INTACT. TEMPERATURE FORECAST THE REAL CHALLENGE...WITH MUCH WARMER TEMPERATURES EXPECTED. WILL HAVE TO WATCH THE HIGH CLOUDINESS AHEAD OF THE SHORTWAVE PUTTING A LID ON AMOUNT OF SUN...BUT GFS MOS APPEARS MUCH TOO COLD BASED ON 850 TEMPERATURES FROM THE ETA/ECMWF AND UKMET. HAVE PLAYED MIDDLE GROUND TO STAY WITHIN TOLERANCE OF NEIGHBORING OFFICES...CLOSE TO FWC GUIDANCE ON SUNDAY THEN SLIGHTLY COOLER ON MONDAY WITH A SHOT OF COOLER AIR COMING IN FROM THE NORTHWEST BEHIND THE SHORTWAVE. COULD POTENTIALLY BE EVEN WARMER...WITH RECORDS THIS TIME OF YEAR STILL IN THE UPPER 80S AND LOWER 90S. && .LONG TERM...(TUESDAY THROUGH FRIDAY) MAIN FORECAST PROBLEM WILL BE TIMING OF LONGWAVE TROUGH FORECAST TO MOVE ACROSS THE ROCKIES WEDNESDAY. AS OF THE 12Z MODEL RUNS...THE OPERATIONAL GFS FASTEST AND IRONICALLY THE ONLY CLOSED UPPER LOW SOLUTION. DGEX SLIGHTLY SLOWER...WHILE CANADIAN GLOBAL AND ECMWF CONSIDERABLY SLOWER KICKING OUT THE SYSTEM. ALL THE MODELS FORECASTING STRONGEST DYNAMICS TO BE SOUTH OF THE FORECAST AREA...WITH SURFACE CYCLOGENESIS MOST LIKELY IN THE OKLAHOMA OR TEXAS PANHANDLES WEDNESDAY THEN QUICKLY MOVING EASTWARD WEDNESDAY NIGHT. FORECAST AREA WILL BE ON THE COLD SIDE OF THE SYSTEM FOR THE DURATION...SPILLING IN WITH NORTH WINDS ON WEDNESDAY. PRECIPITATION WILL BE DEPENDENT ON STRENGTH OF LOW LEVEL UPSLOPE FLOW...THE MAIN LIFTING MECHANISM. EASTERN ZONES MAY GET SOME WRAPAROUND WEDNESDAY NIGHT AND THURSDAY MORNING. WILL HAVE TO WATCH FOR THE SLOWER SOLUTIONS AS WELL...WHICH MAY ALLOW SHOWERS TO CONTINUE INTO THURSDAY. MUCH WEAKER KICKER SHORTWAVE TO MOVE THROUGH ON FRIDAY...BUT DYNAMICS WILL MOVE OVER THE FORECAST AREA THIS TIME AND SHOULD BE ENOUGH FOR SOME SHOWER ACTIVITY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 253 PM EDT FRI OCT 15 2004 .SHORT TERM (TONIGHT THROUGH SATURDAY)... WATER VAPOR LOOP SHOWS A VIGOROUS WAVE TRACKING NORTHEAST ACROSS THE OHIO VALLEY...AS THE TROUGH BEGINS TO TILT TO A NEGATIVE ORIENTATION. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 120-140KT SOUTHWESTERLY JET ACROSS THE SOUTHEAST CONUS...WHILE A 120KT NORTHWESTERLY JET WAS LOCATED ACROSS THE CENTRAL CONUS. 13Z SURFACE ANALYSIS PLACES A 991MB OCCLUDED LOW EAST OF DETROIT...WITH THE TRIPLE POINT LOCATED NEAR PITTSBURGH. A WARM/STATIONARY FRONT EXTENDS EAST-SOUTHEAST FROM THE TRIPLE POINT THROUGH THE CENTRAL DELMARVA...WHILE THE COLD FRONT WAS PUSHING ACROSS THE APPALACHIANS. A PRE-FRONTAL TROUGH WAS NEARING THE BLUE RIDGE. LOCAL ACARS SOUNDING AND KLWX VAD WIND PROFILE SHOW WINDS AND WIND SHEAR INCREASING THROUGH THE COLUMN. TRACK OF THE MIDLEVEL SYSTEM TO THE NORTHEAST ACROSS THE OHIO VALLEY WILL SLOW ANY FRONTAL PASSAGE. FOR THIS REASON PREFER THE SLOWER ETA OVER THE GFS FRONTAL TIMING. BROKEN LINE OF CONVECTION IS DEVELOPING ACROSS THE SHENANDOAH VALLEY NEAR THE COLD FRONT. SPORADIC CLOUD-TO-GROUND LIGHTNING HAS BEEN RECORDED ALREADY. HIGH AMOUNT OF DEEP LAYER SHEAR AND DYNAMICAL FORCING WILL MAINTAIN SUPPORT FOR A LINE OF DEEPER SHOWER ACTIVITY. SURFACE WINDS EVEN IN THE WARM SECTOR EAST OF THE BLUE RIDGE REMAIN SLIGHTLY BACKED DUE TO THE TRANSLATION OF THE SYSTEM AND RESULTANT PRESSURE FALLS TO OUR NORTHWEST. AS THE FRONT/LINE OF SHOWERS REACHES THE BLUE RIDGE...LOW LEVEL CONVERGENCE WILL INCREASE WHEN COMPARED TO CURRENT POSITION OF THE FRONTAL BOUNDARY. THIS WILL FAVOR DEEPENING CONVECTION. ANY DEEP SHOWER/CONVECTION ALONG THE FRONTAL BOUNDARY WILL HAVE THE ABILITY TO PROVIDE FOR GUSTY TO DAMAGING WINDS...AS THE FRONT TRANSLATES EAST OF THE BLUE RIDGE DURING THE EARLY AFTERNOON TO THE CHESAPEAKE BAY BY LATE AFTERNOON. 12Z RUC BUFKIT FORECAST SOUNDINGS INDICATE 0-1KM SHEAR OF 30-40KT THIS AFTERNOON EAST OF THE BLUE RIDGE. IF DEEP CONVECTION WERE TO DEVELOP...ENVIRONMENT IS FAVORABLE FOR A SEVERE WEATHER EPISODE WHICH MAY INCLUDE SHORT LIVED TORNADOES IN ADDITION TO GUSTY TO DAMAGING WINDS SUSTAINED AND SOMEWHAT GUSTY WESTERLY WINDS ANTICIPATED EARLY OVERNIGHT BEHIND THE FRONTAL PASSAGE...ALTHOUGH PRESSURE RISES ARE RATHER INSIGNIFICANT BEHIND THE PRIMARY BOUNDARY. MAINTAINED POPS INTO THE EVENING WITH ONGOING CONVECTION...AND OVERNIGHT WEST OF THE ALLEGHENY FRONT WITH UPSLOPE FLOW. SECONDARY COLD FRONT PASSES THROUGH TOMORROW. THIS BOUNDARY DOES POSSES A PRESSURE RISE CENTER...AND THIS WILL ALLOW GUSTY WINDS TO TRANSLATE TO THE SURFACE BEGINNING DURING MID MORNING MIXING. MAINTAINED SLIGHT CHANCE POPS ACROSS THE WESTERN AND NORTHERN FORECAST AREA DUE TO PRESENCE OF UPSLOPE/INSTABILITY. && .LONG TERM...SAT NGT THROUGH FRI... UPR COLD POOL WL BE SWINGING THRU SAT NGT-SUN MRNG...GIVING CWFA A GLANCING BLOW. WNDS WL STAY UP AS WELL...W/ H8 WNDS AOA 40 KT BY 12Z/17. SIGNIFICANTLY DRIER AIR WL BE ADVECTED IN THEREAFTR...AND WUD ANTICIPATE CLRG SKIES THRU THE AFTN ON SUN. HIPRES RDG /SFC-H8/ WL BE CNTRLLG WX FEATURE. CI FM NEXT SYSTEM STARTS STREAMING IN ELY MON MRNG. MON WL BE A DAY OF WAA...AND THUS INCRSG CLDCVR. MOST FORCING HOLDS OFF TIL TUE. HWVR...PLENTY SOURCES OF LIFT /PVA...WAA...ISEN UPGLIDE...AND EVENTUAL WK WMFNT/ TO INCREASE POPS THRU MON NGT. STAYED ON THE COOL SIDE OF MOS ENVELOPE DUE TO CAA SAT NGT. NO SIG CHGS TO MAXT SUN. DID NOT GO AS XTRM AS MET MOS SUN NGT...BUT DID GO ON COLD SIDE AGN DUE TO CLR SKIES AND LGT WNDS. XTNDD...SFC LOW SPINS INTO GRTLKS AND WEAKENS. ATTENDANT CDFNT APPROACHES CWFA ON TUE. MARGIN OF ERROR FAIRLY HIGH THO AS FRNTL BNDRY STALLS AND BECOMES QSTNRY ACRS CWFA. AMS WL BE WARM/HUMID TO THE S...COOL/DAMP TO THE N. ATTM...AM RELUCTANT TO CHG FCST SIGNIFICANTLY DUE TO THE INHERENT UNCERTAINTIES SURROUNDING PINNING DOWN THE FRNTL POSN THIS FAR OUT. FAIRLY SAFE TO SAY THAT BEST CHC FOR PCPN WL BE ON TUE AS FRNT APPCHS...AND AGN THU NGT-FRI AS ENERGY EJECTS FM SRN STREAM SYSTEM INVOF TX/OK. TIMING OF LATTER FROPA SUSPECT AS WELL...SINCE UPR RDGG WL REMAIN IN PLACE ACRS WRN ATLC. HV MINIMIZED DIURNAL RANGES IN TEMP CURVE DUE TO XTNSV CLDCVR. OTRW...FEW CHGS MADE THRU THE PD. && .AVIATION: CEILINGS WILL LOWER WITH THE APPROACH OF THE FRONTAL BOUNDARY FROM THE WEST DURING THE MID AFTERNOON. BASED ON ABOVE THINKING AND CURRENT RADAR...HAVE INCLUDED MENTION OF THUNDER WITH THE FRONT. SOUTHERLY WINDS MAY GUST AHEAD OF THE FRONT...WITH WINDS EXPECTED TO INCREASE FROM THE WEST WITH THE FRONTAL PASSAGE THIS AFTERNOON. WINDS SHOULD SLACKEN OVERNIGHT...ONLY TO GUST AGAIN TOMORROW AFTER MORNING MIXING. && .MARINE...SCA CONDS ATTM IN THE SLY FLOW AHD OF THE CDFNT. SCA WL CONT TNGT THRU SUN IN STRONG POST-FRNTL CAA. 25 KT WNDS ONLY SVRL HND FT OFF THE WATER...AND WL EASILY MIX TO SFC SAT AFTN. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY TIDAL POTOMAC RIVER AND CHESAPEAKE BAY. && $$ SHORT TERM/AVIATION FORECASTER: ROGOWSKI LONG TERM/MARINE FORECASTER: HTS md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 331 PM EDT FRI OCT 15 2004 .DISCUSSION... THE MAIN CONCERN WITH THIS UPDATE IS THE RAIN AND SNOW POTENTIAL AND WINDS SATURDAY AND SATURDAY NIGHT. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A CLOSED LOW OVER LAKE ERIE EMBEDDED IN A LONG WAVE TROUGH OF CENTRAL CANADA. A BROAD RIDGE IS IN THE GULF OF ALASKA. ANOTHER WEAKER LOW IS OVER MINNESOTA WORKING ITS WAY THROUGH THE BASE OF THE LONGWAVE TROUGH. SURFACE ANALYSIS INDICATES A DEEP LOW OVER LAKE HURON WITH A COLD FRONT EXTENDING DOWN THE ATLANTIC SEABORD. COLD AIR WRAPPING AROUND THE BACKSIDE OF THIS LOW IS PUSHING INTO THE NORTHERN PLAINS ALONG WITH A SURFACE RIDGE. THE MOISTURE WRAPPING AROUND THE SURFACE LOW OVER LAKE HURON IS CONTRIBUTING THE RAIN OCCURRING OVER THE FORECAST AREA THIS AFTERNOON. THE MID LEVEL LOW OVER LAKE ERIE WILL WEAKEN OVERNIGHT AND MERGE WITH THE LOW OVER MINNESOTA AS IT SLIDES INTO THE CENTRAL LAKE MICHIGAN. 850-500MB Q-VECTOR CONVERGENCE ANALYSIS SUGGEST THAT MOST OF THE ENERGY WILL REMAIN OVER WISCONSIN. SURFACE LOW WILL SHIFT NORTH INTO EAST CENTRAL ONTARIO. 290K ISENTROPIC ANALYSIS CONTINUE TO SHOW WEAK ASCENT OVER THE AREA. ETA/GFS FORECAST SOUNDINGS SHOWING NEARLY SATURATED CONDITIONS OVER THE FORECAST AREA FROM SURFACE TO 500MB. THUS WITH THE WEAK ASCENT AND AVAILABLE LOW LEVEL MOISTURE EXPECT TO SEE RAINS CONTINUE OVERNIGHT. THE LAPSE RATE OF 5-6 C/KM OVER THE FORECAST AREA WILL AID IN THE MIXING DOWN TO SURFACE OF THE 850MB WINDS...ESPECIALLY OVER THE WARMER LAKE SUPERIOR WATER. THE MID LEVEL LOW WILL SHIFT INTO EAST CENTRAL ONTARIO ON SATURDAY WHILE THE SURFACE LOW WILL REACH SOUTHERN JAMES BAY. A WEAK SURFACE TROUGH ROTATING AROUND THIS LOW WILL SWING THROUGH THE FORECAST AREA AS THE SHORTWAVE ENERGY SHIFTS ACROSS THE AREA. GFS AND ETA SHOW WEAK ASCENT CONTINUING THROUGH SATURDAY. THUS STILL LOOKING FOR CHANGE OF PRECIPITATION. GFS FORECAST SOUNDINGS PROJECT THE 850MB TEMPERATURES AT -3C OVER THE EAST PART OF CWA TO -6C OVER THE WEST. THUS SNOW STILL LOOKS LIKELY OVER THE WEST WITH RAINS OVER EAST FOR SATURDAY. THE STEEP LOW LEVEL LAPSE RATES LOOKS CONDUCIVE FOR MUCH OF 40 TO 50 KNOT LOW LEVEL JET WINDS TO MIX TO SURFACE ON SATURDAY...ESPECIALLY OVER THE CENTRAL LAKE SUPERIOR AND THE KEWEENAW PENINSULA. THUS WILL HAVE HIGH WIND ADVISORIES OVER THE KEWEENAW PENISULA AND ALGER AND LUCE COUNTIES. THE MID LEVEL LOW WILL CONTINUE TO TREK NORTH INTO SOUTHERN JAMES BAY SATURDAY NIGHT. THE SURFACE LOW WILL PRECEDE THIS LOW INTO SOUTHERN HUDSON BAY WHILE DRAGGING THE COLD FRONT INTO EASTERN ONTARIO. COLD DRY AIR BEHIND THE FRONT WILL SPREAD ACROSS THE FORECAST AREA. GFS/ETA SHOWING LOW LEVEL CONVERGENCE OVER CENTRAL LAKE SUPERIOR. LOW LEVEL CONVERGENCE OVER THE LAKE AND LAKE/850MB DELTA-T'S OR 14C WILL SUPPORT SOME LAKE EFFECT RAIN/SNOWS ESPECIALLY OVER THE EASTERN PART OF CWA. COOL DRY AIR WILL SPREAD INTO THE AREA ON SUNDAY AS THE LOWS CONTINUE TO TREK NORTH INTO HUDSON BAY AND A SURFACE RIDGE PUSHES INTO THE UPPER GREAT LAKES REGION. AS THE MID LEVEL CLOSED LOW MOVES INTO SOUTHERN HUDSON BAY...THE RIDGE WILL SHIFT ACROSS THE AREA MONDAY NIGHT AND TUESDAY. THE SHORTWAVE ENERGY WILL SLOWLY SHIFT EAST AS THE SURFACE RIDGE MOVES OVER THE FORECAST AREA. THIS SHOULD END PRECIPITATION ON MONDAY. THE MID LEVEL LOW OVER THE PACIFIC COAST WILL START TO FILL. ANOTHER SHORTWAVE MOVING THROUGH THE RIDGE OVER THE NORTHERN PLAINS WILL SHIFT INTO WISCONSIN ON TUESDAY. DRY AIR WILL REMAIN IN PLACE AND SHOULD LIMIT ANY PRECIPITATION. A COLD FRONT WILL MOVE INTO NORTHWEST WISCONISON WEDNESDAY NIGHT. THE FRONT WILL NAVIGATE ACROSS THE U.P. THURSDAY AND THURSDAY NIGHT. ISENTROPIC ASCENT ACCOMPNAYING THE FRONT AND WRAP AROUND MOISTURE WILL GENERATE A RAIN SHOWERS OVER THE FORECAST AREA THURSDAY NIGHT AND FRIDAY. DRY AIR WILL FEED INTO THE WESTERN U.P. ON FRIDAY AND DIMINISH CHANCES OF SHOWERS. && .MQT WATCHES/WARNINGS/ADVISORIES...HIGH WIND WATCH SAT/SAT EVNG && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 300 PM CDT FRI OCT 15 2004 .DISCUSSION...FORECAST FOCUS ON TIMING OF PRECIPITATION IN RESPONSE TO CHANGING UPPER AIR FLOW. IN THE SHORT TERM...BRIEF BREAK IN PRECIPITATION EARLY TONIGHT OVER CWA BEFORE AREA OF PRECIPITATION APPROACHING MISSISSIPPI RIVER MOVES ACROSS REGION. ETA/NGM/GFS/RUC CAPTURE ESSENCE OF UPPER SYSTEM WITH ASSOCIATED SURFACE TROUGH BUT LIGHT NATURE OF PRECIPITATION DICTATES ONLY CHANCY MENTION. BUFKIT AND THICKNESS PROGS HINT AT SMALL CHANCE OF SNOW SHOWERS FOR NORTHERN PORTIONS OF CWA EARLY SATURDAY BEFORE PRECIPITATION COMES TO AN END. FOR NOW WILL MENTION A MIXTURE OF RAIN AND SNOW SHOWERS IN THE AREA. EXPECT A WINDY CHILLY DAY OVER CWA SATURDAY AS COLD AIR ADVECTION TAKES HOLD UNDER DECENT CYCLONIC CIRCULATION FROM DEPARTING LOW TO THE EAST. IN THE FAR TERM...GFS/ETA/DGEX PROGS IN DISAGREEMENT WITH TIMING OF PRECIPITATION FOR EARLY NEXT WEEK. THUS WILL USE BROAD BRUSH TO SHOW A WET AND SOMEWHAT WARMER PERIOD OF WEATHER THROUGH MID WEEK AS WIND FIELDS TURN TO A MORE SOUTHWEST DIRECTION AND PERSIST. && .MKX...WATCHES/WARNINGS/ADVISORIES...NONE. $$ ZAJDEL wi