Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/07/12


AREA FORECAST DISCUSSION
NWS ALBANY NY
1026 PM EDT SAT OCT 6 2012 .SYNOPSIS... MUCH COOLER AIR WILL CONTINUE TO STREAM INTO OUR REGION OVERNIGHT AS WEAK HIGH PRESSURE CRESTS ACROSS THE REGION. LOW PRESSURE WILL MOVE ALONG A FRONTAL BOUNDARY STALLED JUST TO OUR SOUTH GIVING US MORE UNSETTLED WEATHER FOR SUNDAY AFTERNOON INTO SUNDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION ON MONDAY AND BRING FAIR AND SEASONABLE WEATHER FOR THE FIRST HALF OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 1026 PM EDT...A BAND OF LAKE EFFECT RAIN SHOWERS HAS DEVELOPED OFF LAKE ONTARIO. WHILE THE MAJORITY OF THESE RAIN SHOWERS ARE REMAINING CLOSE TO THE LAKESHORE AND ACROSS THE TUG HILL...A FEW SHOWERS WILL MAKE IT INTO THE FAR WESTERN ADIRONDACKS. AS THE FLOW SHIFTS...THIS BAND WILL GRADUALLY SHIFT SOUTH...POSSIBLY AFFECTING PARTS OF THE WESTERN MOHAWK VALLEY BY LATE TONIGHT. THIS IS BEING MODELED WELL BY THE LATEST HRRR AND LOCAL WRF. MEANWHILE...A SFC FRONTAL BOUNDARY CONTINUES TO MOVE TO THE SOUTH AND EAST OF OUR AREA ACROSS EASTERN NEW ENGLAND AND DOWN OFF THE MID ATLANTIC SEABOARD. WITH HIGH PRSSURE NOSING INTO THE AREA...THIS SHOULD ALLOW FOR MOSTLY CLEAR TO PARTLY CLOUDY SKIES FOR THE MAJORITY OF THE NIGHT. MID AND HIGH LEVEL CLOUDS WILL START TO INCREASE TOWARDS DAYBREAK AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONTAL BOUNDARY TO OUR SOUTH. MIN TEMPS OVERNIGHT WILL BE MUCH COOLER THAN RECENT NIGHTS DUE TO THE COOLER AIR MASS MOVING INTO THE REGION. MIN TEMPS WILL RANGE FROM JUST BELOW FREEZING ACROSS THE HIGHER PEAKS OF THE CENTRAL ADIRONDACKS TO NEAR 40 IN THE HUDSON VALLEY AND NORTHWESTERN CT. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/... WHILE SFC CDFNT WILL STALL WELL OFFSHORE...THE COLD AIR REMAINS SHALLOW AND THE H850 BAROCLINIC ZN/THERMAL RIBBON ONLY MOVES JUST OFFSHORE. ALL THE MODEL SUITE (NAM/GFS/ECMWF/CMC) HAS COME INTO AGREEMENT NOW SUN...WITH THE GFS JOINING THE OTHERS. STRONG 500HPA SHORT WV EJECTS E FM OH VLY...ACROSS THE BAROCLINIC ZONE... AND CLOUDS (DURING THE MORNING) AND WAA/OVERRUNNING RN (AFTN AND EVENING) SPREAD QUICKLY NE BACK INTO THE REGION SUNDAY. FORTUNATELY THIS SYSTEM IS FAST MOVING AND CYCLOGENISUS IS MINIMAL...RAIN EXITS OVERNIGHT WITH MOST AREAS SUBJECT TO 6-12 HOURS OF RAIN SUN AFTN AND EVENING. WITH CLOUDS AND CAA TEMPS WILL BE QUITE COOLER THAN THEY HAVE HAVE BEEN AND SVRL DEGREES BLO NORMALS. THERE WILL ALSO BE BRIEF PERIODS WHERE CONDS SUPPORT LK EFFECT -SHRA AND SH-SN AT NIGHT OVER HIR TRRN TNGT AND SUN NIGHT...BUT CHANGES IN FLOW AND WEAK FLOW WILL KEEP THIS CONFINED TO TUG HILL AND LT. AT 500HPA BROAD TROF OVER MID CONTINENT WILL RESULT IN SW FLOW ACROSS FCA..AS SERIES OF SHORT WVS DIVE INTO TROF MOST ROTATING WELL SOUTH OR NORTH OF REGION TILL WED. COLUMBUS DAY COOL HIGH PRESSURE BUILDS FM OH VLY INTO NEW ENG. SOME WK LK RESPONSE MAY LINGER INTO MONDAY MORNING IN N HERK/HAM COUNTIES...BUT WITH SFC/LLVL FLOW BCMG LT AND SW...THIS WILL END. SFC HI PRESSURE WILL REMAIN OVER THE RGN MON INTO WED MRNG. GEN PC/CLEAR CONDS...SOME PATCHY CLOUDS IN MID LVL WAA N TIER..BUT A FINE FALL PERIOD OF WX...NR NORMAL TEMPS...LT WINDS. BY WED 500 TROF AXIS HAS SHIFTED E TO GRTLKS...AND SERIES OF SHORT WVS DRIVES A CDFNT THRU FCA DURING LATE AFTN AND EVNG. THIS IS ANOTHER ANNA TYPE EVENT LIKE TDY (SAT) WITH PD OF LT RAIN POST FRONTAL. MORNING LOWS MONDAY AND TUES UNDER CLEAR SKIES AND SFC HI W/12.5 PLUS HOURS OF NIGHT WILL HAVE NO PROBLEM FALLING INTO MID 20S TO MID 30S. WOULD SUSPECT THIS TIME TOMORROW WE WILL BE CONSIDERING FROST AND FREEZE FLAGS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... OTHER THAN MINOR TIMING DIFFERENCES ECMWF AND GFS IN REASONABLE AGREEMENT. POPULATED WITH GMOS MAKING MINOR CHANGES. MID CONTINENT 500HPA TROF GRADUALLY SLIDES EASTWARD DURING THIS PERIOD AS A 500HPA RIDGE BUILDS IN ITS WAKE INTO THE GRTLKS TO END THE PERIOD. THE PARADE OF SHORT WAVES CONTINUE TO MIGRATE AROUND THE BASE OF THE TROF IN THE FAST FLOW. HIGH PRESSURE PASSES FM OH VLY TO MID ATLC STATES THUR WITH GENERALLY FAIR CONDS. CLOUDS MAY INCR N AHEAD OF NEXT SYSTEM THU AFTN AS PER GFS...BUT ECMWF KEEPS THIS MOISTURE N OF RGN. THE NEXT SHORT WV TO DRIVE A CDFNT THROUGH RGN IS FRI WITH WHAT APPEARS TO BE YET ANOTHER ANNA TYPE CDFNT WITH PD OF LT RAIN IN ITS WAKE. WITH TROF AXIS HAVING MOVED E TO OVER NY/NEW ENG FRI NIGHT...CAA SURGE WILL BE STRONGER THE PVS FEW...WITH MINS IN 20S TO LOW 30S MOST AREAS...AND WARMER READINGS CONFINED TO FAR SE. WHERE THE GROWING SEASON IS STILL BARELY HANGING ON...IT SHOULD BE OVER IN MOST AREAS BY THE WEEKEND. THE WEEKEND STARTS WITH ANOTHER HIGH PRESSURE AREA IN THE FAST FLOW PASSING ACROSS RGN SAT. HWVR THE PERIOD ENDS WITH 500HPA TROF EXITING...RIDGING IN ITS WAKE AND WAA OVERSPREADING THE RGN FM THE WEST IN SPLIT FLOW. TEMPS WILL REMAIN BLO NORMS FOR MOST OF THIS PERIOD. WHILE DRY AND FAIR MUCH OF THE TIME A CDFNT WILL BRING A CHC OF -SHRA FRI AND RAIN MAY OVERSPREAD THE REGION TO END THE WEEK. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... VFR FLYING CONDITIONS ARE EXPECTED THROUGH MUCH OF THE OVERNIGHT HOURS WITH JUST FEW-SCT STRATOCU CLOUDS AROUND 4-6 KFT...MAINLY DURING THE EVENING HOURS. SOME MID AND HIGH LEVEL CLOUDINESS WILL MOVE INTO THE AREA TOWARDS DAYBREAK. LIGHT WESTERLY WINDS WILL BE IN PLACE TONIGHT...AND WITH DEWPOINTS DROPPING DOWN INTO THE 30S...NO RADIATIONAL FOG IS EXPECTED TO DEVELOP TONIGHT. BKN-OVC MID LEVEL CLOUDINESS WILL BE IN PLACE FOR SUNDAY MORNING. SOME RAIN WILL MOVE INTO THE REGION FROM SOUTH TO NORTH DURING THE AFTN/EVE HOURS. THE MODELS ARE NOT IN AGREEMENT YET WITH THE EXACT TIMING AND PLACEMENT OF THIS RAIN...BUT IT/S POSSIBLE THAT RAIN HOLDS OFF FOR KALB/KGFL UNTIL 00Z MONDAY. KPSF/KPOU HAVE A BETTER CHC OF SEEING SOME LIGHT RAIN DURING THE AFTN OR EVENING HOURS. FLYING CONDITIONS COULD DROP TO MVFR WITHIN ANY RAINFALL. WESTERLY WINDS WILL CONTINUE TO BE RATHER LIGHT. OUTLOOK... SUN NT...VFR/MVFR. CHC/LIKELY -SHRA SUN EVENING. MON-TUE NT...VFR. NO SIG WX. WED...VFR. CHC MVFR IN SHOWERS. THU...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER RELATED ISSUES ARE EXPECTED. A WAVE OF LOW PRESSURE WILL MOVE ALONG THE FRONTAL BOUNDARY STALLED JUST TO OUR SOUTH GIVING MOST AREAS OVER A QUARTER INCH OF RAIN SUNDAY. HIGH PRESSURE WILL BUILD INTO THE REGION ON MONDAY WITH FAIR AND COOL WEATHER INTO WEDNESDAY WHEN ANOTHER FRONTAL SYSTEM WILL BRING A PERIOD OF SHOWERS. && .HYDROLOGY... NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT 7 DAYS. AROUND A QUARTER INCH OF RAINFALL IS EXPECTED SUNDAY AFTERNOON/EVENING AND WEDNESDAY AFTERNOON/EVENING. IN THE TUG HILL PLATEAU LAKE EFFECT RAIN SHOWERS...AND OVER THE HIGHER TERRAIN AT NIGHT SNOW SHOWERS...WILL PRODUCE UP TO AN INCH LIQUID TOTAL THIS WEEK. THESE AMOUNTS WILL BE INSUFFICIENT TO PRODUCE MUCH RESPONSE IN RIVERS AND CREEKS THIS WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS/SNYDER NEAR TERM...FRUGIS SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...FRUGIS FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
424 AM EDT FRI OCT 5 2012 .SYNOPSIS... A FRONTAL BOUNDARY JUST OFF THE CAROLINA COAST THIS MORNING WILL PUSH FARTHER OUT TO SEA TODAY. WEAK HIGH PRESSURE WILL BE OVER THE FORECAST AREA TODAY THROUGH SATURDAY. A COLD FRONT WILL MOVE INTO THE AREA SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... THE WEAK FRONTAL BOUNDARY HAS GONE AND HIGH PRESSURE HAS BEGUN TO BUILD IN ACROSS THE FORECAST AREA THROUGH TODAY INTO TONIGHT. SATELLITE LOOPS SHOWS THE BACK EDGE OF A CIRRUS SHIELD CONTINUES TO RUN SW TO NE ACROSS THE WESTERN PORTION OF THE CWA. AT TIMES THE CLOUDINESS HAS BEEN SCATTERED AND THIN...BUT CURRENTLY IS A BIT THICKER AND MORE WIDESPREAD. AMOUNT/THICKNESS OF HIGH CLOUDINESS TOWARD DAYBREAK WILL WEIGH ON THE AMOUNT OF RADIATIONAL COOLING AND FOG FORMATION. PATCHY FOG...POSSIBLY LOCALLY DENSE...IS POSSIBLE NEAR SUNRISE. WEAK HIGH PRESSURE WILL DOMINATE TODAY AND TONIGHT. MODEL TIME SECTIONS SHOW A RELATIVELY DRY AIRMASS ACROSS THE AREA THROUGH THE PERIOD. GUIDANCE AND LOCAL NUMBERS VERY CLOSE FOR TEMPERATURES AND WILL STAY NEAR CONSENSUS THROUGH THE PERIOD. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... BY SATURDAY INTO SATURDAY NIGHT...ALL OF THE MODELS INDICATE THAT A FRONTAL BOUNDARY WILL BE APPROACHING THE AREA FROM THE WEST. WITH FRONTAL BOUNDARY NEARLY PARALLEL TO MID/UPPER FLOW...LOOKS LIKE THE FRONT WILL BE A SLOW MOVER INTO THE REGION. WILL LIKELY HAVE TO WAIT FOR MORE VIGOROUS SHORTWAVE ENERGY EXPECTED TO MOVE ACROSS THE MIDWEST/GREAT LAKES REGION BY SUNDAY FOR FRONT TO MOVE INTO REGION. THE ECMWF IS STILL THE SLOWEST OF THE MODELS...BUT GFS/NAM ALONG WITH ECMWF HAVE COME INTO BETTER AGREEMENT WITH THE 00Z MODEL RUN. GUIDANCE AND LOCAL NUMBERS SHOW WARM TEMPERATURES FOR THE PERIOD WITH TEMPERATURES RUNNING NEARLY 10 DEGREES ABOVE NORMAL. WILL STAY NEAR A CONSENSUS OF THE GUIDANCE AT THIS TIME THROUGH THE PERIOD. HPC ANALYSIS INDICATES A COMPROMISE BETWEEN THE SOLUTIONS MAY BE THE BEST TIMING FOR THE FRONT. WITH FRONT APPROACHING BY SATURDAY NIGHT...HAVE INCLUDED A SLIGHT CHANCE/LOW CHANCE OF SHOWERS ACROSS THE NORTH/NORTHWEST MIDLANDS. GUIDANCE NUMBERS ONCE AGAIN VERY CONSISTENT AND WILL STAY NEAR CONSENSUS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... LATEST ECMWF/GFS CONTINUES TO SHOW A COLD FRONT THAT WILL BE MOVING INTO THE AREA ON SUNDAY. A COMPROMISE BETWEEN THE FASTER GFS AND SLOWER ECMWF WILL BE USED. CONTINUED WITH A CHANCE OF SHOWERS SUNDAY/SUNDAY NIGHT. SREF ENSEMBLE GUIDANCE INDICATED THE BEST CHANCE FOR RAIN TO BE SUNDAY AFTERNOON/EVENING. TEMPERATURES WILL BE TRICKY ON SUNDAY BASED ON THE ARRIVAL OF THE FRONTAL BOUNDARY...BUT EXPECT COOLER TEMPERATURES BY MONDAY. BEHIND THE FRONT...COOL HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY THROUGH TUESDAY NIGHT. TEMPERATURES SHOULD BEGIN TO GRADUALLY RISE THROUGH THE REMAINDER OF THE LONG TERM PERIOD...BUT REMAIN BELOW NORMAL. LOOKS LIKE THE AREA WILL SEE THE COOLEST TEMPERATURES OF THE FALL PERIOD BY TUESDAY MORNING AS MANY AREAS WILL FALL INTO THE MIDDLE TO UPPER 40S. TEMPERATURES WILL GRADUALLY MODERATE WEDNESDAY INTO THURSDAY. ANOTHER DRY COLD FRONT APPROACHES FROM THE WEST LATE WEDNESDAY INTO EARLY THURSDAY. EXPECT TEMPERATURES TO REMAIN BELOW NORMAL THROUGH THE PERIOD. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... THIN HIGH CLOUDS CONTINUES ACROSS THE AREA BUT WITH LIGHT BOUNDARY LAYER WINDS...HIGH NEAR-SURFACE RELATIVE HUMIDITY...FOG DEVELOPING AT AREA TERMINALS. RADIATION FOG SCHEME ALONG WITH LATEST HRRR AND LAMP SUGGEST WIDESPREAD MVFR THROUGH 09Z THEN LIFR/IFR AROUND 12Z POSSIBLE ESPECIALLY AT AGS/OGB. VISIBILITY MAY STAY UP AT DNL...CROSS OVER TEMPERATURE LOWER THAN OTHER TERMINAL SITES AND STRATUS NOT FORECAST. EXTENDED AVIATION OUTLOOK...REDUCED VISIBILITY IN EARLY MORNING FOG POSSIBLE. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 07/77
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
105 AM EDT FRI OCT 5 2012 .SYNOPSIS... A FRONTAL BOUNDARY JUST OFF THE CAROLINA COAST WILL FINALLY PUSH FURTHER OUT TO SEA OVERNIGHT. WEAK HIGH PRESSURE WILL BE OVER THE FORECAST AREA TODAY THROUGH SATURDAY. A COLD FRONT WILL MOVE INTO THE AREA SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE WEAK FRONTAL BOUNDARY HAS GONE AND HIGH PRESSURE WILL BUILD ACROSS THE FORECAST AREA OVERNIGHT. THE BACK EDGE OF A CIRRUS SHIELD CONTINUES TO RUN SW TO NE ACROSS THE WESTERN PORTION OF THE CWA. AT TIMES THE CLOUDINESS IS SCATTERED AND THIN. AMOUNT/THICKNESS OF HIGH CLOUDINESS TOWARD MORNING WILL WEIGH ON THE AMOUNT OF RADIATIONAL COOLING AND FOG FORMATION. PATCHY FOG...POSSIBLY LOCALLY DENSE...IS POSSIBLE NEAR SUNRISE. WILL CONTINUE TO MONITOR AREA OBS IN CASE A DENSE FOG ADVISORY MAY BE NEEDED. LOW TEMPERATURES ARE EXPECTED TO BE IN THE MIDDLE TO UPPER 50S. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... THE SHORT TERM WILL BEGIN WITH WEAK HIGH PRESSURE ACROSS THE AREA ON FRIDAY INTO FRIDAY NIGHT. BY SATURDAY INTO SATURDAY NIGHT...ALL OF THE MODELS INDICATE THAT A FRONTAL BOUNDARY WILL BE APPROACHING THE AREA FROM THE WEST. WITH FRONTAL BOUNDARY NEARLY PARALLEL TO MID/UPPER FLOW...LOOKS LIKE THE FRONT WILL BE A SLOW MOVER INTO THE REGION. WILL LIKELY HAVE TO WAIT FOR MORE VIGOROUS SHORTWAVE ENERGY EXPECTED TO MOVE ACROSS THE MIDWEST/GREAT LAKES REGION BY SUNDAY FOR FRONT TO MOVE INTO REGION. GUIDANCE AND LOCAL NUMBERS SHOW WARM TEMPERATURES FOR THE PERIOD WITH TEMPERATURES RUNNING NEARLY 10 DEGREES ABOVE NORMAL. WILL STAY NEAR A CONSENSUS OF THE GUIDANCE AT THIS TIME THROUGH THE PERIOD. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... LATEST GFS CONTINUES TO SHOW AN APPROACHING COLD FRONT MOVING INTO THE FORECAST AREA SUNDAY. CONTINUED WITH A CHANCE OF SHOWERS SUNDAY/SUNDAY NIGHT. SREF ENSEMBLE GUIDANCE INDICATED THE BEST CHANCE FOR RAIN TO BE SUNDAY AFTERNOON/NIGHT. TEMPERATURES WILL BE TRICKY ON SUNDAY BASED ON THE ARRIVAL OF THE FRONTAL BOUNDARY...BUT EXPECT COOLER TEMPERATURES BY MONDAY. TEMPERATURES SHOULD BEGIN TO GRADUALLY RISE THROUGH THE REMAINDER OF THE LONG TERM PERIOD...BUT REMAIN BELOW NORMAL. LOOKS LIKE THE AREA WILL SEE THE COOLEST TEMPERATURES OF THE FALL PERIOD BY TUESDAY MORNING AS MANY AREAS WILL FALL INTO THE UPPER 40S. TEMPERATURES WILL GENERALLY MODERATE WEDNESDAY INTO THURSDAY. ANOTHER DRY COLD FRONT APPROACHES FROM THE WEST LATE WEDNESDAY INTO EARLY THURSDAY. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... THIN HIGH CLOUDS CONTINUES ACROSS THE AREA BUT WITH LIGHT BOUNDARY LAYER WINDS...HIGH NEAR-SURFACE RELATIVE HUMIDITY...FOG DEVELOPING AT AREA TERMINALS. RADIATION FOG SCHEME ALONG WITH LATEST HRRR AND LAMP SUGGEST WIDESPREAD MVFR THROUGH 09Z THEN LIFR/IFR AROUND 12Z POSSIBLE ESPECIALLY AT AGS/OGB. VISIBILITY MAY STAY UP AT DNL...CROSS OVER TEMPERATURE LOWER THAN OTHER TERMINAL SITES AND STRATUS NOT FORECAST. EXTENDED AVIATION OUTLOOK...REDUCED VISIBILITY IN EARLY MORNING FOG POSSIBLE. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 07/77
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1011 AM CDT FRI OCT 5 2012 .DISCUSSION... ISSUED 958 AM CDT FRI OCT 5 2012 BAND OF STEADIER RAIN HAS SHIFTED SOUTH AND WAS CENTERED ALONG THE I-70 CORRIDOR LATE THIS MORNING...WITH SCATTERED SHOWERS TO THE NORTHWEST. LATEST RAP MODEL KEEPS THE BULK OF THE RAIN SOUTH OF A DANVILLE TO TAYLORVILLE LINE THE REMAINDER OF THE DAY...ALTHOUGH THE HRRR AND NAM-12 SHOW SOME FILLING IN OF THE SCATTERED RAIN ACROSS THE NORTHWEST CWA. TEMPERATURES ARE GOING NOWHERE FAST... EXCEPT IN THE EXTREME SOUTHEAST WHERE THE RAIN HAS NOT STARTED YET. HAVE LOWERED HIGH TEMPERATURES OVER MOST OF THE CWA...WITH VALUES ONLY RISING A COUPLE MORE DEGREES ESPECIALLY IN THE RAINY AREAS. UPDATED ZONES/GRIDS HAVE BEEN SENT. GEELHART && .AVIATION... ISSUED 605 AM CDT FRI OCT 5 2012 COLD FRONT WHICH PUSHED ACRS OUR AREA YESTERDAY AFTERNOON AND EVENING HAS SHIFTED WELL SOUTH OF THE TAF SITES EARLY THIS MORNING. WEAK LOW PRESSURE ALONG THE BOUNDARY TO OUR SOUTHWEST HAS PRODUCED BANDS OF SHOWERS AND ISOLD TSRA THRU EARLY THIS MORNING ALONG WITH AREAS OF MVFR CIGS...ESPECIALLY WHERE THE MORE CONCENTRATED AREA OF STEADIER RAINS HAS OCCURRED. WE EXPECT SIMILAR CONDITIONS TO PREVAIL THRU MOST OF THE DAY WITH FORECAST SOUNDINGS SUGGESTING OCNL MVFR OR LOWER CIGS IN RAIN WITH THE POSSIBILITY FOR ISOLD CONVECTION AS WELL...ESPECIALLY AT SPI... DEC...AND CMI. THE RAIN SHIELD WILL GRADUALLY BEGIN TO SHIFT SOUTHEAST LATE TODAY AS THE SFC HIGH BUILDS SE INTO THE MIDWEST BRINGING VFR CONDITIONS TO THE REMAINDER OF THE FORECAST AREA AFTR 01Z. SFC WINDS WILL BE OUT OF THE N-NW AT AROUND 10 KTS DURING THE DAY...AND THEN DROP TO BETWEEN 5 AND 10 KTS TONIGHT. SMITH && .PREV DISCUSSION... ISSUED 214 AM CDT FRI OCT 5 2012 SHORT TERM...TODAY THROUGH SUNDAY 06Z/1AM SURFACE ANALYSIS SHOWS COLD FRONT JUST NORTH OF THE OHIO RIVER...WITH CHILLY AIRMASS SETTLING SOUTHWARD INTO THE REGION. WELL NORTH OF THE BOUNDARY...FRONTOGENETIC FORCING ALONG THE MID-LEVEL BAROCLINIC ZONE IS TRIGGERING A BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS FROM SOUTHEAST KANSAS NORTHEASTWARD INTO CENTRAL ILLINOIS. AT THE CURRENT TIME...THE RAIN IS MAINLY CENTERED ALONG A WATSEKA...TO LINCOLN...TO PITTSFIELD LINE. A CLOSER LOOK AT FORCING SHOWS THE NAM 850MB FRONTOGENESIS FIELD DEPICTING THE RAIN BAND QUITE NICELY...SO WILL FOLLOW THIS PARAMETER CLOSELY FOR THE SHORT-TERM FORECAST. WITH REGION REMAINING IN THE RIGHT ENTRANCE REGION OF A 300MB JET STREAK ACROSS THE GREAT LAKES AND PRIMARY MID-LEVEL FORCING ONLY VERY SLOWLY SINKING SOUTHWARD...THINK SHOWERS WILL BE WIDESPREAD ACROSS THE CENTRAL AND SOUTHERN KILX CWA FOR MUCH OF THE DAY. BASED ON LATEST RADAR LOOPS AND NAM FRONTOGENESIS...HAVE FOCUSED HIGHEST POPS ALONG/SOUTH OF A RUSHVILLE TO BLOOMINGTON-NORMAL LINE THROUGH MIDDAY. AFTER THAT...STRONGEST FORCING SHIFTS SOUTH TO ALONG THE I-70 CORRIDOR DURING THE AFTERNOON. GIVEN STEEP LAPSE RATES ABOVE 700MB...WILL CONTINUE TO MENTION ISOLATED THUNDER THROUGHOUT THE DAY AS WELL. RAIN TOTALS COULD EXCEED 1 INCH IN SOME LOCATIONS ACROSS THE CENTRAL CWA...WITH AMOUNTS RAPIDLY DROPPING TO LESS THAN ONE QUARTER OF AN INCH ACROSS THE FAR NORTH AROUND GALESBURG. WITH COOL N/NE FLOW AND OFF-AND-ON SHOWERS...TEMPS WILL REMAIN NEARLY STEADY IN THE UPPER 40S AND LOWER 50S. AS SHORT-WAVE PUSHES EAST OF THE AREA...FRONT WILL FINALLY GET SHOVED FURTHER SOUTH TONIGHT. MOST MODEL GUIDANCE IS SUGGESTING SHOWERS PERSISTING ACROSS THE E/SE CWA THROUGH EVENING...BEFORE GRADUALLY EXITING INTO INDIANA OVERNIGHT. WILL THEREFORE MAINTAIN CHANCE POPS ALONG/EAST OF I-55 THROUGH MIDNIGHT...THEN JUST ACROSS THE FAR SE AROUND LAWRENCEVILLE OVERNIGHT. FORECAST SOUNDINGS INDICATE CLEARING SKIES FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA TONIGHT...WITH MOST LOCATIONS SEEING CLEAR SKIES BY DAWN SATURDAY. GIVEN CLEARING SKIES AND CONTINUED CAA...OVERNIGHT LOWS WILL DROP INTO THE MIDDLE TO UPPER 30S. AFTER A COOL/DRY DAY ON SATURDAY...A VIGOROUS SHORT-WAVE WILL DIVE OUT OF CANADA AND TRACK ACROSS THE AREA SATURDAY NIGHT. PREVIOUS MODEL SOLUTIONS HAD SUGGESTED THAT THIS FEATURE COULD PULL THE FRONT BACK NORTHWARD A BIT...POTENTIALLY BRINGING CLOUDS/SHOWERS INTO THE SE CWA. THE 00Z NAM AND GFS BOTH KEEP ANY PRECIP WELL SOUTH OF THE AREA...SO HAVE REMOVED PRECIP MENTION. MAIN STORY WILL BE THE COLD WEATHER AND POTENTIAL FOR FREEZING TEMPS AND/OR FROST. WITH SHORT-WAVE MOVING THROUGH THE AREA...PARTIAL CLOUD COVER WILL LIKELY MITIGATE RADIATIONAL COOLING TO SOME EXTENT. IN ADDITION...WITH SURFACE HIGH CENTERED OVER THE PLAINS...LIGHT N/NW WINDS MAY ALSO PREVENT TEMPS FROM DROPPING AS LOW AS THEY WOULD OTHERWISE. AS A RESULT...DO NOT THINK THERE WILL BE A WIDESPREAD FROST OR FREEZE. INSTEAD...MOST LOCATIONS WILL DROP INTO THE MIDDLE 30S...WITH A FEW FAVORED LOW-LYING/RURAL SPOTS DIPPING TO NEAR OR SLIGHTLY BELOW FREEZING. BETTER OPPORTUNITY FOR FROST/FREEZE MAY DEVELOP SUNDAY NIGHT ACROSS THE E/SE CWA AS RIDGE AXIS SLIDES EASTWARD INTO THE OHIO RIVER VALLEY BY 12Z MON. LIGHTEST WINDS WILL LIKELY OCCUR ALONG/SOUTHEAST OF A CHAMPAIGN TO TAYLORVILLE LINE...SO THIS WILL BE THE AREA TO WATCH FOR POTENTIAL WIDESPREAD FREEZE. FURTHER WEST...WEAK RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL KEEP TEMPS A COUPLE OF DEGREES WARMER. LONG TERM...MONDAY THROUGH THURSDAY MODERATING TEMPS ARE IN STORE FOR MONDAY AND TUESDAY...AS SOUTHERLY FLOW BOOSTS HIGH TEMPS BACK INTO THE 60S. NEXT UPPER-WAVE AND ASSOCIATED COLD FRONT IS SLATED TO APPROACH THE AREA LATE TUESDAY INTO WEDNESDAY. 00Z GFS TRIES TO SPREAD SHOWERS INTO WEST-CENTRAL ILLINOIS AS EARLY AS TUESDAY AFTERNOON...HOWEVER GIVEN DRY AIRMASS IN PLACE...HAVE OPTED TO KEEP TUESDAY DRY. WILL INSTEAD FOCUS POPS TUESDAY NIGHT...WHEN BOTH THE GFS AND ECMWF AGREE THAT FRONT WILL PASS THROUGH. AFTER THAT...DRY WEATHER AND SLIGHTLY COOLER TEMPS IN THE UPPER 50S/LOWER 60S WILL BE IN STORE FOR BOTH WEDNESDAY AND THURSDAY. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
644 AM CDT FRI OCT 5 2012 .UPDATE... AS EXPECTED...THERE HAS BEEN A BRIEF LULL WITH PRECIP DROPPING DOWN TO MAINLY SPRINKLES. RADARS THE PAST 30-45 MINUTES HAVE SHOWN NEW DEVELOPMENT ACROSS NORTHERN MISSOURI AND INTO EXTREME SOUTHERN IOWA. SOME OF THIS IS LIKELY MID LEVEL CLOUDS BASED ON APPEARANCE AND CORRELATION WITH SATELLITE IMAGES. HOWEVER...SOME OF IT IS LEGITIMATE SPRINKLES OR HIGH BASED SHRA ASSOCIATED WITH SOME FORCING. SFC OBS INDICATE A WEAK TROF FROM ROUGHLY NORTHERN WISCONSIN TO NEAR KOMA. RAP TRENDS SHOW THIS FORCING CONTINUING INTO THE MORNING COMMUTE BEFORE WEAKENING. THUS ANOTHER LULL MIGHT OCCUR FOR A FEW HOURS LATE THIS MORNING BEFORE PRECIP RE-DEVELOPS AGAIN WITH THE ARRIVAL OF THE SHORTWAVE. THE RAP AND WRF MODELS SUGGEST THE WEAK TROF MOVING THROUGH IOWA MAY PROVIDE SOME ADDITIONAL FOCUS FOR DIURNAL SHRA ACTIVITY OVER NOT QUITE THE SOUTHEAST HALF OF THE CWFA DURING THE AFTERNOON HOURS. EXTRAPOLATION OF THE 12HR RAP POSITIONS SUGGEST THE POSSIBILITY OF SOME SPRINKLES LINGERING PAST 00Z IN THE FAR EAST/SOUTHEAST PARTS OF THE CWFA. THE 06Z MODELS CONTINUE TO SHOW THE UPPER JET OVER THE AREA TONIGHT SUGGESTING CS/CI MAY COME INTO PLAY WITH TEMPERATURES. THE 2 METER TEMPS FROM THE WRF LOOK TOO COLD. HOWEVER...IF CLOUD COVER IS THIN ENOUGH THE DRY GROUND MAY NEGATE THE AFFECTS OF THE CLOUDS. THUS THE POTENTIAL IS STILL THERE FOR POSSIBLE FREEZE HEADLINES TONIGHT. ..08.. && .AVIATION... VFR WX IS EXPECTED THROUGH 12Z/06 AS HIGH PRESSURE SLOWLY BUILDS INTO THE MIDWEST. A DISTURBANCE MOVING THROUGH MAY PRODUCE SOME SPRINKLES OR A LIGHT SHRA AT KMLI/KBRL. CLEARING SKIES AND DECREASING WINDS AFT SUNSET MAY RESULT IN FROST FORMATION ON NON- HANGARED ACFT. ..08.. && .PREV DISCUSSION... /ISSUED 324 AM CDT FRI OCT 5 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS THE COLD FRONT FROM LAKE HURON INTO TEXAS WITH SFC WAVES IN SOUTHWEST MISSOURI AND NORTH TEXAS. A WEAK TROF RAN FROM SOUTHERN LAKE MICHIGAN BACK TO THE KMCI AREA WITH ANOTHER FROM LAKE SUPERIOR TO NEAR KHON. DEW POINTS ALONG AND SOUTH OF THE FRONT WERE IN THE 50S AND 60S WITH 40S FROM LAKE MICHIGAN INTO KANSAS. DEW POINTS IN THE 20S AND 30S WERE ACROSS MUCH OF THE PLAINS AND UPPER MISSISSIPPI VALLEY. SHORT TERM...TODAY AND TONIGHT... RADAR RETURNS SHOW A WEAK AREA OF SPRINKLES/SHRA FROM SOUTH OF KIOWA BACK THROUGH SOUTHERN IOWA. THIS PRECIPITATION APPEARS TO BE DUE TO A MOISTURE AND THETA E GRADIENT PER RAP TRENDS AND THE OTHER MODELS. THESE FEATURES WILL SLOWLY WEAKEN THE REMAINDER OF THE NIGHT INTO THE MORNING COMMUTE. THE BETTER FORCING WITH THE MORE SUBSTANTIAL SHRA ACTIVITY WILL CONTINUE ACROSS THE FAR SOUTHERN PARTS OF THE CWFA THROUGH THE MORNING COMMUTE AS WELL. THERE MAY OR MAY NOT BE A LULL IN THE PRECIPITATION DURING THE LATE MORNING HOURS WHILE THE NEXT SHORTWAVE APPROACHES FROM THE PLAINS. DURING THE AFTERNOON THIS SHORTWAVE MOVES ACROSS THE AREA. THERE IS A COUPLED UPPER JET STRUCTURE WHICH WILL PROVIDE GENERAL SYNOPTIC LIFT. THE SOUTH HALF OF THE CWFA WILL HAVE THE BETTER CHANCE AT SEEING SHRA ACTIVITY. TONIGHT...THERE MAY OR MAY NOT BE SOME LINGERING SPRINKLES IN THE FAR EAST FOR A FEW HOURS. ALL MODELS SHOW A MOISTURE GRADIENT OVER THE AREA WITH A DIFFUSE BUT WEAKENING THETA E GRADIENT. SO...HAVE OPTED TO KEEP TONIGHT DRY. THE LARGER CONCERN IS TEMPERATURES. ALL MODELS SHOW THE UPPER JET OVER THE AREA WHICH COULD PROVIDE SOME CI/CS WHILE IN THE LOWER LEVELS THE MODELS SUGGEST CLOUDS WITH THE INCREASING CYCLONIC FLOW FROM THE SHORTWAVE DROPPING DOWN FROM THE NORTH. INTERESTINGLY... THE MODELS ARE INDICATING SUBSIDENCE AND THUS POSSIBLE CLEAR SKIES. CLOUD COVER WILL BE THE KEY TO HOW COLD IT GETS. IF THERE ARE CLOUDS BUT THEY ARE THIN...THEN THE DRY GROUND MAY OFFSET THE CLOUDS AND ALLOW TEMPERATURES TO DROP MORE THAN FCST. THE POTENTIAL DOES EXIST FOR FREEZE HEADLINES FOR TONIGHT FROM ABOUT HWY 30 ON SOUTH. ..08.. LONG TERM...SATURDAY THROUGH THURSDAY... THIS EXTENDED PERIOD WILL MAINLY FOCUS ON TEMPERATURES WITH ACTIVE...YET MAINLY DRY NORTH TO NORTHWEST FLOW. SATURDAY SHOULD BE QUITE COLD AND WITH A STRATOCUMULUS DECK SPREADING OVER THE REGION EARLY IN THE DAY...WE MAY BE HARD PRESSED TO REACH 50 IN MANY LOCATIONS. FOR NOW...IT IS MOST LIKELY TO BE CLOUDY EARLY ENOUGH IN THE DAY TO HOLD THE NORTH 1/3 TO THE UPPER 40S FOR HIGHS...WHILE THE SOUTH COULD REACH THE LOWER 50S. THIS MOST CERTAINLY APPEARS TO BE THE COLDEST DAY IN THIS CURRENT STRETCH OF CHILLY WEATHER. SATURDAY NIGHT...ALL MODELS DECREASE SKY COVER FROM WEST TO EAST DURING THE LATE AFTERNOON/EARLY EVENING HOURS. COMBINED WITH LIGHT WINDS AND LINGERING VERY COLD AIRMASS ALOFT...WE SHOULD DROP TO LOWS IN THE 20S OVER MOST OF THE CWA...WITH SOME LOWER TO MID 20S IN FAVORED LOWER LYING AREAS. SHOULD TONIGHT NOT RESULT IN FREEZE CONDITIONS...HEADLINES SHOULD BE REQUIRED FOR SATURDAY NIGHT. SUNDAY BEGINS SEVERAL DAYS OF MODERATION TO MORE COMFORTABLE WEATHER...WITH HIGHS REACHING THE MID 50S WITH PLENTY OF SUN...THEN AFTER A COOL NIGHT IN THE 30S...MONDAY SHOULD SEE A RETURN TO THE LOWER 60S. UNFORTUNATELY...THIS WARMTH WILL ARRIVE WITH STRONGER WINDS...THUS SENSIBLE WEATHER WILL BE PRETTY BRISK OUT THERE. TUESDAY...A PASSING WAVE IN NORTHWEST FLOW SHOULD KEEP US MILD AGAIN...WITH A CHANCE FOR RAIN SHOWERS. MODELS INDICATE THAT GOOD MOISTURE MAY BE NEAR OR JUST PASS SOUTH OF THE CWA. SO...WHILE CHANCE ARE INCREASED FROM PRIOR FORECASTS...THE AMOUNTS MAY BE QUITE LIGHT. AFTER TUESDAY...MORE DRY WEATHER WITH CANADIAN HIGH PRESSURE IS IN STORE FOR WEDNESDAY AND THURSDAY. LOWS IN THE 30S AND HIGHS IN THE 50S WED/60S THU ARE EXPECTED. ERVIN CLIMATE... RECORD LOWS FOR OCTOBER 7... MOLINE.........27 IN 1952 CEDAR RAPIDS...25 IN 2001 DUBUQUE........23 IN 2000 BURLINGTON.....26 IN 1952 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
324 AM CDT FRI OCT 5 2012 .SYNOPSIS... 06Z SFC ANALYSIS HAS THE COLD FRONT FROM LAKE HURON INTO TEXAS WITH SFC WAVES IN SOUTHWEST MISSOURI AND NORTH TEXAS. A WEAK TROF RAN FROM SOUTHERN LAKE MICHIGAN BACK TO THE KMCI AREA WITH ANOTHER FROM LAKE SUPERIOR TO NEAR KHON. DEW POINTS ALONG AND SOUTH OF THE FRONT WERE IN THE 50S AND 60S WITH 40S FROM LAKE MICHIGAN INTO KANSAS. DEW POINTS IN THE 20S AND 30S WERE ACROSS MUCH OF THE PLAINS AND UPPER MISSISSIPPI VALLEY. && .SHORT TERM...TODAY AND TONIGHT... RADAR RETURNS SHOW A WEAK AREA OF SPRINKLES/SHRA FROM SOUTH OF KIOWA BACK THROUGH SOUTHERN IOWA. THIS PRECIPITATION APPEARS TO BE DUE TO A MOISTURE AND THETA E GRADIENT PER RAP TRENDS AND THE OTHER MODELS. THESE FEATURES WILL SLOWLY WEAKEN THE REMAINDER OF THE NIGHT INTO THE MORNING COMMUTE. THE BETTER FORCING WITH THE MORE SUBSTANTIAL SHRA ACTIVITY WILL CONTINUE ACROSS THE FAR SOUTHERN PARTS OF THE CWFA THROUGH THE MORNING COMMUTE AS WELL. THERE MAY OR MAY NOT BE A LULL IN THE PRECIPITATION DURING THE LATE MORNING HOURS WHILE THE NEXT SHORTWAVE APPROACHES FROM THE PLAINS. DURING THE AFTERNOON THIS SHORTWAVE MOVES ACROSS THE AREA. THERE IS A COUPLED UPPER JET STRUCTURE WHICH WILL PROVIDE GENERAL SYNOPTIC LIFT. THE SOUTH HALF OF THE CWFA WILL HAVE THE BETTER CHANCE AT SEEING SHRA ACTIVITY. TONIGHT...THERE MAY OR MAY NOT BE SOME LINGERING SPRINKLES IN THE FAR EAST FOR A FEW HOURS. ALL MODELS SHOW A MOISTURE GRADIENT OVER THE AREA WITH A DIFFUSE BUT WEAKENING THETA E GRADIENT. SO...HAVE OPTED TO KEEP TONIGHT DRY. THE LARGER CONCERN IS TEMPERATURES. ALL MODELS SHOW THE UPPER JET OVER THE AREA WHICH COULD PROVIDE SOME CI/CS WHILE IN THE LOWER LEVELS THE MODELS SUGGEST CLOUDS WITH THE INCREASING CYCLONIC FLOW FROM THE SHORTWAVE DROPPING DOWN FROM THE NORTH. INTERESTINGLY... THE MODELS ARE INDICATING SUBSIDENCE AND THUS POSSIBLE CLEAR SKIES. CLOUD COVER WILL BE THE KEY TO HOW COLD IT GETS. IF THERE ARE CLOUDS BUT THEY ARE THIN...THEN THE DRY GROUND MAY OFFSET THE CLOUDS AND ALLOW TEMPERATURES TO DROP MORE THAN FCST. THE POTENTIAL DOES EXIST FOR FREEZE HEADLINES FOR TONIGHT FROM ABOUT HWY 30 ON SOUTH. ..08.. .LONG TERM...SATURDAY THROUGH THURSDAY... THIS EXTENDED PERIOD WILL MAINLY FOCUS ON TEMPERATURES WITH ACTIVE...YET MAINLY DRY NORTH TO NORTHWEST FLOW. SATURDAY SHOULD BE QUITE COLD AND WITH A STRATOCUMULUS DECK SPREADING OVER THE REGION EARLY IN THE DAY...WE MAY BE HARD PRESSED TO REACH 50 IN MANY LOCATIONS. FOR NOW...IT IS MOST LIKELY TO BE CLOUDY EARLY ENOUGH IN THE DAY TO HOLD THE NORTH 1/3 TO THE UPPER 40S FOR HIGHS...WHILE THE SOUTH COULD REACH THE LOWER 50S. THIS MOST CERTAINLY APPEARS TO BE THE COLDEST DAY IN THIS CURRENT STRETCH OF CHILLY WEATHER. SATURDAY NIGHT...ALL MODELS DECREASE SKY COVER FROM WEST TO EAST DURING THE LATE AFTERNOON/EARLY EVENING HOURS. COMBINED WITH LIGHT WINDS AND LINGERING VERY COLD AIRMASS ALOFT...WE SHOULD DROP TO LOWS IN THE 20S OVER MOST OF THE CWA...WITH SOME LOWER TO MID 20S IN FAVORED LOWER LYING AREAS. SHOULD TONIGHT NOT RESULT IN FREEZE CONDITIONS...HEADLINES SHOULD BE REQUIRED FOR SATURDAY NIGHT. SUNDAY BEGINS SEVERAL DAYS OF MODERATION TO MORE COMFORTABLE WEATHER...WITH HIGHS REACHING THE MID 50S WITH PLENTY OF SUN...THEN AFTER A COOL NIGHT IN THE 30S...MONDAY SHOULD SEE A RETURN TO THE LOWER 60S. UNFORTUNATELY...THIS WARMTH WILL ARRIVE WITH STRONGER WINDS...THUS SENSIBLE WEATHER WILL BE PRETTY BRISK OUT THERE. TUESDAY...A PASSING WAVE IN NORTHWEST FLOW SHOULD KEEP US MILD AGAIN...WITH A CHANCE FOR RAIN SHOWERS. MODELS INDICATE THAT GOOD MOISTURE MAY BE NEAR OR JUST PASS SOUTH OF THE CWA. SO...WHILE CHANCE ARE INCREASED FROM PRIOR FORECASTS...THE AMOUNTS MAY BE QUITE LIGHT. AFTER TUESDAY...MORE DRY WEATHER WITH CANADIAN HIGH PRESSURE IS IN STORE FOR WEDNESDAY AND THURSDAY. LOWS IN THE 30S AND HIGHS IN THE 50S WED/60S THU ARE EXPECTED. ERVIN && .AVIATION... VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS WITH SPOTTY SHOWERS FRONTAL CLOUD BAND HAS EXITED THE CWA WHILE MID AND HIGH LEVEL CLOUDS FROM THE FIRST OF TWO SHORTWAVE TROUGHS ENTER THE AREA. THE FIRST TROUGH WILL PASS THROUGH EARLY TODAY AND THE SECOND THIS AFTERNOON...AND BOTH WILL PRODUCE INTERMITTENT BOUTS OF LIGHT RAIN...PRIMARILY AT KBRL. OTHER TAF SITES SHOULD REMAIN DRY. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ 08/ERVIN/08
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
621 PM CDT SAT OCT 6 2012 ...UPDATED FOR THE 00Z TAF AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1256 PM CDT SAT OCT 6 2012 A DEEP LONGWAVE TROUGH ENCOMPASSED MUCH OF THE NORTHERN CONUS WITH 250MB CYCLONICALLY CURVED FLOW FROM THE GREAT BASIN THROUGH THE GREAT PLAINS TO THE GREAT LAKES REGION. WITHIN THE LONGWAVE TROUGH...A SHORTWAVE TROUGH WAS MOVING SOUTHEAST THROUGH WESTERN NEBRASKA EARLY SATURDAY. 12Z UPPER AIR ANALYSIS REVEALED 700MB FRONTOGENETIC ZONE EXTENDING FROM SOUTHERN WYOMING THROUGH EASTERN COLORADO TO SOUTHWESTERN KANSAS WITH SATURATED OR NEAR SATURATED AIR (700MB DEWPOINT DEPRESSIONS 0 OR 1 DEGC AT KRIW, KDNR, KDDC, KAMA, KOUN). PRECIPITATION IN THE FORM OF RAIN AND SNOW EXTENDED ALL ALONG THE STRONGEST ZONE OF MID LEVEL FRONTOGENESIS (THE STRONGEST OF WHICH FROM NORTHEAST COLORADO TO NORTHWEST KANSAS TO FAR SOUTHWEST NEBRASKA AS OF 17Z). LIGHTER BANDED PRECIPITATION WAS FOUND ACROSS SOUTHWEST KANSAS WHERE 0.06 INCHES OF PRECIPITATION WAS MEASURED SO FAR AT DODGE CITY (ALL IN THE FORM OF RAIN). SNOW WAS REPORTED AS FAR SOUTHEAST AS DIGHTON...AND VERY BRIEFLY MIXED IN WITH RAIN ACROSS THE NORTHWEST PORTIONS OF FORD COUNTY DURING ONE OF THE HEAVIER BANDS EARLIER THIS MORNING. IT SEEMS THE SNOW LINE IS MATCHING UP WELL WITH THE RAP ANALYZED 900 FT AGL FREEZING LEVEL...WHICH EXTENDED FROM ROUGHLY GARDEN CITY TO DIGHTON (AND POINTS NORTHWEST) AT 18Z. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 316 PM CDT SAT OCT 6 2012 THIS EVENING: MID LEVEL FRONTOGENESIS (MAINLY CENTERED AROUND 700MB) WILL CONTINUE TO DECREASE ACROSS WEST CENTRAL AND CENTRAL KANSAS AS THE MID LEVEL SHORTWAVE TROUGH ACROSS SOUTHWEST NEBRASKA MOVES TOWARD SOUTHEAST NEBRASKA. MID LEVEL DRYING FROM 800 TO 500MB (AND ABOVE THROUGH THE UPPER TROPOSPHERE) WILL INCREASE AS SUBSIDENCE PREVAILS IN THE WAKE OF THE PRIMARY SHORTWAVE TROUGH. MOISTURE AND ATTENDANT CLOUD IN THE LOWER TROPOSPHERE (800-900MB) WILL ALSO BE DECREASING...HOWEVER RATE OF DECREASE ACROSS SOUTHWEST AND WEST CENTRAL KANSAS IS STILL A FAIRLY CHALLENGING FORECAST AS LOW STRATUS WILL BE DIFFICULT TO DISLODGE AS REMNANT LOW LEVEL MOISTURE RECIRCULATES AROUND THE ANTICYCLONE IN THIS LAYER. FEEL THAT CLOUDS IN THE 800-900MB LAYER WILL SCATTER OUT SLOWLY FROM 00-06Z TONIGHT...AND MOST PROMINENT FARTHER NORTHEAST AWAY FROM COLORADO. OVERNIGHT: A 1030MB SURFACE HIGH WILL BE MOVING SOUTH-SOUTHEAST WITH CENTER OF SURFACE HIGH TAKING A TRACK FROM ROUGHLY WRAY, COLORADO TO DODGE CITY TONIGHT. ALONG THE TRACK OF THE SURFACE HIGH SKY SHOULD CLEAR OUT AFTER MIDNIGHT...AND TEMPERATURES WILL FALL INTO THE LOWER 30S RATHER QUICKLY ONCE CLOUDS CLEAR. TEMPERATURES WILL MOST LIKELY FALL TO 28 TO 30 DEGREES NORTH OF THE ARKANSAS RIVER BY 08 OR 09Z AND REMAIN IN THIS RANGE FOR PROBABLY 4 OR 5 HOURS...WITH MINIMUM AROUND SUNRISE OF 25 TO 27 DEGREES NORTH OF A DIGHTON TO NESS CITY TO LACROSSE LINE. THIS IS MORE OR LESS A CONTINUATION OF THE PREVIOUS FORECAST AND AM NOT MAKING ANY CHANGES TO THE GOING FREEZE HEADLINES. WILL CONTINUE THE HARD FREEZE WARNING (28 DEGREES OR BELOW FOR LOWS) NORTH OF A JOHNSON TO BUCKLIN TO STAFFORD LINE. SOUTH OF THIS LINE TO THE OKLAHOMA BORDER WILL CONTINUE WITH THE FREEZE WARNING FOR LOWS 29 TO 32 DEGREES. MUCH, IF NOT ALL, OF WEST CENTRAL, SOUTHWEST, AND SOUTH CENTRAL KANSAS WILL SEE THE END TO THE GROWING SEASON WITH THESE FORECAST TEMPERATURES TONIGHT. SUNDAY: A SECONDARY MINOR SHORTWAVE DISTURBANCE WILL BE ROTATING AROUND THE MEAN TROUGH AXIS FROM SOUTHERN WYOMING TO NORTHEASTERN NEW MEXICO...WHICH MAY BRING SOME MID LEVEL CLOUD BACK TO FAR SOUTHWEST KANSAS BY DAYBREAK...HOWEVER NO OTHER SENSIBLE WEATHER IMPACTS ARE EXPECTED WITH THIS FINAL SHORTWAVE TROUGH PASSAGE. THE SURFACE HIGH WILL SHIFT INTO THE RED RIVER VALLEY BY MIDDAY SUNDAY...BUT OVERALL PRESSURE GRADIENT WILL REMAIN RATHER WEAK WITH SOUTHWEST WINDS 8 TO 10 KNOTS EXPECTED. A WARMING OF THE LOWER TROPOSPHERE FROM DOWNSLOPE MOMENTUM (850MB TEMPS INCREASING TO +5 TO +9C FROM EAST TO WEST) WILL ALLOW SURFACE TEMPERATURES TO WARM UP WELL INTO THE MID TO UPPER 50S...ESPECIALLY ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 345 PM CDT SAT OCT 6 2012 MONDAY: BROAD 500-250 HPA WNW FLOW IS EXPECTED MONDAY. THIS ORTHOGONAL FLOW WRT THE ROCKIES WILL ALLOW FOR A LEE TROUGH TO FORM MONDAY FROM THE SURFACE UP TO 850 HPA. AS A RESULT, A WEAK WARM AIR ADVECTION REGIME IS EXPECTED WITH HIGHS MODERATING TO THE UPPER 60S DEG F TO AROUND 70 DEG F. A DRY FORECAST IS EXPECTED FOR THE BEGINNING OF THE WORK WEEK AS THE REGION WILL BE FREE OF ANY SYNOPTIC DISTURBANCES AND ASSOCIATED LIFT. TUESDAY: THE SYNOPTIC PATTERN CHANGES TUESDAY AS A BROAD POSITIVELY TILTED UPPER LEVEL SHORTWAVE TROF EJECTS FROM THE CANADIAN PRAIRIES AND ACROSS THE NORTHERN PLAINS. THIS UL FEATURE WILL USHER IN A PASSAGE OF A COLD FRONT. HAVE USED 12Z ECMWF AS GUIDANCE FOR TEMPERATURES AS THE GFS CONTINUES TO PERFORM POORLY (IN THIS CASE, USUALLY TOO AGGRESSIVE WITH THE FROPA). HIGHS WILL VARY ACROSS THE REGION WITH LOW TO MID 60S DEG F ACROSS THE INTERSTATE 70 CORRIDOR TO MID 70S DEG F ACROSS EXTREME SOUTHWEST KANSAS. THIS FRONT WILL BE DRY WITH A LACK OF BOUNDARY LAYER MOISTURE IN PLACE. WILL KEEP POPS NEAR ZERO PERCENT. SFC WINDS DON`T LOOK PARTICULARLY STRONG WITH THIS HIGH AS 850 HPA WINDS ARE ONLY FORECAST TO BE IN THE 20-25 KT RANGE. WEDNESDAY: A RIDGE OF HIGH PRESSURE WILL TRANSLATE ACROSS THE SUNFLOWER STATE WEDNESDAY IN THE WAKE OF THE DENSITY GRADIENT. HIGHS IN THE 60S DEG F ARE EXPECTED AS FAIRLY COOL 850 HPA TEMPERATURES (9-13 DEG C) ARE FORECAST IN ASSOCIATION WITH THE AFOREMENTIONED COOL HIGH PRESSURE CENTER MOVING ACROSS THE STATE. WILL ALSO RUN WITH THE ALLBLEND POPS (AROUND 3 PERCENT) FOR THE MIDDLE PORTION OF THE WORK WEEK. THURSDAY AND BEYOND: THE FORECAST BECOMES MORE INTERESTING TOWARDS THE END OF THE WORK WEEK ALTHOUGH SYNOPTIC AND MESOSCALE DETAILS ARE VERY UNCERTAIN AT THIS POINT. FOR EXAMPLE, YESTERDAYS ECMWF RUN HAD THE WARM SECTOR (HIGHER THETA-E AIR) SPREADING NORTHWARD IN ASSOCIATION WITH THE PASSAGE OF A WARM FRONT FRIDAY. TODAY`S 12Z ECMWF RUN KEEPS THAT BOUNDARY SOUTH OF THE REGION FRIDAY. THIS BOUNDARY PLACEMENT WILL HAVE SIGNIFICANT IMPACTS IN TERMS OF SENSIBLE WEATHER AS A WAA PATTERN/THETA-E ADVECTION ALONG SAID FRONT COULD LEAD TO THE DEVELOPMENT OF CONVECTION ACROSS THE PLAINS. FOR NOW WILL GO WITH A BLEND OF THE ALLBLEND POPS ALTHOUGH WILL SMOOTH POPS TOWARDS A BIAS TO THE ECMWF. THE GFS WAS GENERALLY DISREGARDED AS THE MODEL CONTINUES TO BE VERY PROGRESSIVE WITH UL FEATURES THAT WILL PROBABLY SLOW DOWN WITH TIME. IT SHOULD BE NOTED THAT MUCH UNCERTAINTY EXISTS WITH THE EVOLUTION OF THE DESERT SOUTHWEST UL LOW THAT WILL BE THE IMPETUS FOR CONVECTION. IT ALSO SHOULD BE NOTED THAT THERE IS THE POSSIBILITY OF SEVERE CONVECTION, PARTICULARLY FRIDAY AND SATURDAY. WARM SECTOR PLACEMENT AND ASSOCIATED REDISTRIBUTION OF ENERGY PER UNIT MASS (I.E. CAPE) IS UNCERTAIN. REGARDLESS OF WHEREVER THE WARM SECTOR WILL BE, THE ECMWF SHOWS SIGNIFICANT BOUNDARY LAYER MOISTURE WORKING ITS WAY NORTH FROM THE GULF OF MEXICO. KINEMATIC PROFILES ALSO STRENGTHEN WITH TIME AS THE UL LOW MOVES CLOSER TO KANSAS WITH 250 HPA FLOW INCREASING TO 100 KT, 500 HPA FLOW INCREASING TO 60 KT, AND FAIRLY STRONG AND VEERING FLOW FROM THE SFC THROUGH 700 HPA. SEVERE WEATHER EPISODES IN OCTOBER ARE NOT UNUSUAL FOR THE PLAINS. IN FACT, THERE WERE TORNADOES LAST OCTOBER ACROSS THE REGION LAST YEAR. IT IS TOO EARLY TO DETERMINE STORM MODE AND PLACEMENT AT THIS TIME BUT IT IS SOMETHING TO WATCH FOR IN FUTURE MODEL RUNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 607 PM CDT SAT OCT 6 2012 AS SURFACE HIGH PRESSURE STRENGTHEN AND THE LOWER LEVEL MOISTURE ADVECTS TO THE EAST, LOW STRATUS CIGS WILL DEVELOP INTO SCATTERED CLOUDS BETWEEN 04 AND 06Z. WINDS WILL BECOME LIGHT AND VARIABLE ABOUT THE SAME TIME. SOME MID LEVEL CLOUDS WILL MOVE INTO SOUTHWEST KANSAS AFTER SAT AT 15Z, MAINLY DUE TO AN UPPER LEVEL WAVE CROSSING FROM FROM COLORADO TO MISSOURI. WINDS ON SATURDAY SHOULD PICK UP FROM THE SOUTH TO SOUTHWEST AT 10 TO 13 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... DDC 28 57 34 69 / 10 10 0 0 GCK 28 57 32 69 / 10 10 0 0 EHA 30 54 35 67 / 10 10 0 0 LBL 30 54 34 67 / 10 10 0 0 HYS 26 58 34 70 / 20 0 0 0 P28 29 56 35 69 / 10 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... HARD FREEZE WARNING FROM 1 AM CDT /MIDNIGHT MDT/ TO 9 AM CDT /8 AM MDT/ SUNDAY FOR KSZ030-031-043>046-061>066-074>079. FREEZE WARNING FROM 1 AM TO 9 AM CDT SUNDAY FOR KSZ080-081- 084>090. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...SUGDEN AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1027 PM EDT SAT OCT 06 2012 .Forecast Update... Updated at 1027 PM EDT Sat Oct 6 2012 HRRR and RAP show KY staying dry tonight and this is supported by regional radars and upstream obs. Decent band of reflectivities passed over Logan and Simpson Counties within the last hour but neither Mesonet station reported measurable rainfall. So, will back off on PoPs a bit. Will still keep some low chances going far south though in case any activity can blossom ahead of the approaching upper trof or slip over the border from Tennessee. && .Short Term (Today through Sunday)... Issued at 300 PM EDT Sat Oct 6 2012 A persistent Rex Block at 500mb just off the Pacific Coast has allowed northerly flow to develop downstream across the Upper Midwest. A chilly Canadian airmass has already penetrated practically as far south as the Texas Gulf coast, and remains banked up against higher terrain in New Mexico and Colorado. Clouds will increase this evening as one of several flat disturbances embedded within a broader 500mb cyclonic gyre scoots across Missouri. Both the GFS and NAM models take this feature across Tennessee and southern Kentucky during the overnight hours. A light chilly rain may develop across our southern counties later this evening, ending around dawn across our southern Bluegrass or Lake Cumberland Region. Precipitation totals will stay light, totaling around two tenths of an inch or less. Feel that Louisville and possible Lexington will stay north of this potential strip of precipitation. Expect a cloudy cool night with lows ranging from just under 40 to the lower 40s. Skies will clear pretty readily Sunday morning as this 500mb wave passes and subsidence overspreads the area. Canadian high pressure will settle over the southern plains by Sunday afternoon, with an axis extending east across the Commonwealth. Light north winds Sunday afternoon will become calm overnight through Monday. Early Monday will provide our best chance for widespread frost and even a chance of a light freeze across some of our colder rural locations. Frost chances will depend on how clear we become by early Monday. High clouds associated with a disturbance over Tennessee may spread as far north as Interstate 64 early Monday. This may, if thick enough, limit frost chances across our south. Agricultural interests should however, plan on at least some frost across southern Indiana and north central Kentucky. Some lows early Monday may reach or approach 32 for a few hours. .Long Term (Monday - Saturday)... Issued at 300 PM EDT Sat Oct 6 2012 High pressure will be over the region Monday morning at the same time a vortmax is crossing the region aloft. Clouds associated with this shortwave will be over or just east of the eastern forecast area at the start of this period. During the day Monday and continuing into Tuesday, the high will become centered over New England. Tuesday night, a cold front will move into the Midwest. Moisture ahead of this front is not that impressive but will be enough to warrant a chance for rain to come through the forecast area. After that front, another cold shot of Canadian air will build into the region, with high pressure becoming centered over the region Thursday morning. Deterministic and Ensemble models support this scenario, meaning another chilly morning with more frost possible Thursday morning. Progressive flow aloft, with persistent troughiness across eastern Canada, will bring another moisture-starved front through the region Friday morning. The high behind this front looks to move more to our north. This may allow for a quicker return of moisture into the area for next weekend. 00Z ECMWF and latest GFS/DGEX all indicate some weak warm frontal-type forcing across the region Saturday, with the latter two bringing rain into the region. For now will lean toward the ECMWF solution, which keeps the best rain chances to our northwest. && .Aviation (00Z TAF Issuance)... Issued at 711 PM EDT Sat Oct 6 2012 An upper shortwave trof exiting the Plains will spread overcast skies across Kentucky tonight. The clouds should stay well VFR other than maybe some scattered 015-030 clouds especially at BWG. The GFS is advertising widespread rain tonight all the way up to the Ohio River. However, the GFS often paints virga as QPF. Looking at several mesoscale models it does appear that radar echoes in the north will be virga as dry surface high pressure noses in beneath the upper wave. A check of upstream obs shows mostly AC ceilings with just a stray sprinkle or two. BWG stands the only real chance of rain tonight, and even there it will be quite light. As the upper trof axis crosses the area Sunday morning the clouds will scatter out and provide us with a very nice day. Winds will be much lighter tonight than they were last night, still out of the northwest. During the day Sunday, especially by afternoon, they should become more WNW and increase a little to around 8 kts. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........13 Short Term.......JSD Long Term........RJS Aviation.........13
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
643 PM EDT FRI OCT 5 2012 .SYNOPSIS... A CANADIAN COLD FRONT...WILL MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY TONIGHT...AND BRING SHOWERS AND MUCH COOLER TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY/... MINOR ADJUSTMENTS TO EVE UPDATE. SOME TIMING CHANGES TO OVERNIGHT POPS AND ADJUSTED TEMPS CLOSER TO LATEST GUIDANCE. PREVIOUS DISCUSSION... JUDGING FROM BLEND OF RECENT SURFACE...RADAR AND SATELLITE DATA...COUPLED WITH RECENT WRF-NMM AND RAP MODEL OUTPUT...CONTINUE TO EXPECT THE MAIN ADIABATIC COLD FRONTAL BAND OF SHOWERS TO MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY LATE TONIGHT INTO SATURDAY MORNING. HOWEVER...MODEL OUTPUT CONTINUES TO SUGGEST THERE CAN BE A THIN BAND OF SCATTERED PREFRONTAL SHOWERS DEVELOPING ACROSS THE UPPER OHIO VALLEY THIS EVENING. EVEN IF SO PRECIPITATION AMOUNTS WOULD BE LIGHT. CONCUR WITH HPC QPF THAT RAIN AMOUNTS LATE TONIGHT INTO SATURDAY MORNING CAN BE UP TO 0.25 INCHES. FORECASTED TEMPERATURES...PER RECENT GFS AND NAM MOS...TO BECOME NOTICEABLY COLDER WITH LOWS TONIGHT DOWN TO NEAR NORMAL WITH HIGHS SATURDAY ABOUT 10 DEGREES COLDER THAN NORMAL. DUE TO SHALLOW BUT VIGOROUS VERTICAL MIXING IN WAKE OF THE COLD FRONTAL PASSAGE...WIND MAY GUST UP TO 20 TO 25 MPH THROUGH DAYTIME SATURDAY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... MORE RECENT SREF MODEL OUTPUT SHOW THE ENSUING LOW PRESSURE WAVE ALONG THE EXITED COLD FRONT WILL AT MOST ONLY MAINLY AFFECT WV-MD MOUNTAINS SATURDAY NIGHT AND SUNDAY. HOWEVER...THE COLD UPPER TROUGH WILL MAINTAIN CLOUDY SKIES INTO MONDAY...AND MAY PROMOTE SCATTERED INSTABILITY SHOWERS LATE SUNDAY ACROSS MAINLY WESTERN PENNSYLVANIA. DUE TO THE COLDNESS OF THE SURFACE LAYER...ITS POSSIBLE HIGHER ELEVATIONS MAY SEE A CHANGE TO LIGHT SNOW SHOWERS AT TIMES...BUT THE GROUND WILL REMAIN TOO WARM FOR ANY IMPACT. FORECASTED SPECIFIC TEMPERATURES USING BLEND OF GFS NAM AND ECMWF MOS...THAT SHOWED VALUES GENERALLY 7 TO 10 DEGREES COLDER THAN NORMAL...WITH HIGHS SUNDAY PERHAPS 10 TO 13 DEGREES COLDER THAN NORMAL. ALTHOUGH MOST LOW TEMPERATURES SUNDAY NIGHT WILL BE IN THE LOWER TO MID 30S...FROST AND FREEZE PROSPECTS WILL DEPEND REMAINING EXTENT OF CLOUD COVER AND WIND...SO HELD OFF ON ANY CORRESPONDING ISSUANCES. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... THE EXTENDED PERIOD BEGINS WITH HIGH PRESSURE RIDGE ALONG MUCH OF THE EASTERN UNITED STATES...WHICH SHOULD PERSIST FROM MONDAY NIGHT INTO TUESDAY NIGHT. LOW PRESSURE IS THEN EXPECTED TO MOVE EAST FROM LAKE HURON...SKIRTING THE U.S.-CANADA BORDER. THE LOW SHOULD BRING A COLD FRONT THROUGH THE REGION ON WEDNESDAY. FOR NOW HAVE STUCK WITH CHANCE POPS DURING THE DAYTIME. THE FRONT SHOULD DROP TEMPERATURES ABOUT 5 DEGREES FROM THE PREVIOUS DAYS READING. HIGH PRESSURE WILL THEN RETURN WEDNESDAY NIGHT AND REMAIN ACROSS THE SOUTHEASTERN UNITED STATES THURSDAY. ANOTHER CANADIAN LOW SHOULD SWEEP A SECOND COLD FRONT THROUGH THURSDAY NIGHT INTO FRIDAY. THIS SHOULD BRING AT LEAST A SLIGHT CHANCE OF SHOWERS DURING THAT TIME PERIOD. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... EXPECT BROKEN LOW VFR CIGS IN DIURNAL CUMULUS THIS AFTERNOON...WITH SW GUSTS UP TO 15-20 KTS POSSIBLE. BY SUNSET STRATUS DECK SHOULD BE MOVING IN FROM THE WEST. THE STRATUS SHOULD PROVIDE VFR CEILINGS...EVENTUALLY DROPPING TO MVFR CIGS AS RAIN MOVES IN AROUND MIDNIGHT. DROPPED CIGS DOWN TO 1KFT AT FKL AND DUJ...BUT NOT ENOUGH CONFIDENCE TO GO IFR AT THIS POINT. WITH RAIN EXPECTED TO FALL PRIMARILY BEHIND THE COLD FRONT...EXPECT WIND SHIFT BEFORE RAIN BEGINS TO FALL. WINDS WILL SHIFT TO THE WEST AND INCREASE AS WIDESPREAD RAIN ENDS SATURDAY MORNING...WITH CIGS REMAINING AT A VFR LEVEL. .OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/... WIDESPREAD LOW VFR/HIGH MVFR CIGS CAN BE EXPECTED ALONG WITH SCATTERED SHOWERS SATURDAY NIGHT INTO SUNDAY. VFR CAN BE EXPECTED SUNDAY NIGHT THROUGH TUESDAY NIGHT BEFORE A COLD FRONT BRINGS POSSIBLE RESTRICTIONS IN SHOWERS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
350 PM EDT FRI OCT 5 2012 .SYNOPSIS... A CANADIAN COLD FRONT...WILL MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY TONIGHT...AND BRING SHOWERS AND MUCH COOLER TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY/... JUDGING FROM BLEND OF RECENT SURFACE...RADAR AND SATELLITE DATA...COUPLED WITH RECENT WRF-NMM AND RAP MODEL OUTPUT...CONTINUE TO EXPECT THE MAIN ADIABATIC COLD FRONTAL BAND OF SHOWERS TO MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY LATE TONIGHT INTO SATURDAY MORNING. HOWEVER...MODEL OUTPUT CONTINUES TO SUGGEST THERE CAN BE A THIN BAND OF SCATTERED PREFRONTAL SHOWERS DEVELOPING ACROSS THE UPPER OHIO VALLEY THIS EVENING. EVEN IF SO PRECIPITATION AMOUNTS WOULD BE LIGHT. CONCUR WITH HPC QPF THAT RAIN AMOUNTS LATE TONIGHT INTO SATURDAY MORNING CAN BE UP TO 0.25 INCHES. FORECASTED TEMPERATURES...PER RECENT GFS AND NAM MOS...TO BECOME NOTICEABLY COLDER WITH LOWS TONIGHT DOWN TO NEAR NORMAL WITH HIGHS SATURDAY ABOUT 10 DEGREES COLDER THAN NORMAL. DUE TO SHALLOW BUT VIGOROUS VERTICAL MIXING IN WAKE OF THE COLD FRONTAL PASSAGE...WIND MAY GUST UP TO 20 TO 25 MPH THROUGH DAYTIME SATURDAY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... MORE RECENT SREF MODEL OUTPUT SHOW THE ENSUING LOW PRESSURE WAVE ALONG THE EXITED COLD FRONT WILL AT MOST ONLY MAINLY AFFECT WV-MD MOUNTAINS SATURDAY NIGHT AND SUNDAY. HOWEVER...THE COLD UPPER TROUGH WILL MAINTAIN CLOUDY SKIES INTO MONDAY...AND MAY PROMOTE SCATTERED INSTABILITY SHOWERS LATE SUNDAY ACROSS MAINLY WESTERN PENNSYLVANIA. DUE TO THE COLDNESS OF THE SURFACE LAYER...ITS POSSIBLE HIGHER ELEVATIONS MAY SEE A CHANGE TO LIGHT SNOW SHOWERS AT TIMES...BUT THE GROUND WILL REMAIN TOO WARM FOR ANY IMPACT. FORECASTED SPECIFIC TEMPERATURES USING BLEND OF GFS NAM AND ECMWF MOS...THAT SHOWED VALUES GENERALLY 7 TO 10 DEGREES COLDER THAN NORMAL...WITH HIGHS SUNDAY PERHAPS 10 TO 13 DEGREES COLDER THAN NORMAL. ALTHOUGH MOST LOW TEMPERATURES SUNDAY NIGHT WILL BE IN THE LOWER TO MID 30S...FROST AND FREEZE PROSPECTS WILL DEPEND REMAINING EXTENT OF CLOUD COVER AND WIND...SO HELD OFF ON ANY CORRESPONDING ISSUANCES. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... THE EXTENDED PERIOD BEGINS WITH HIGH PRESSURE RIDGE ALONG MUCH OF THE EASTERN UNITED STATES...WHICH SHOULD PERSIST FROM MONDAY NIGHT INTO TUESDAY NIGHT. LOW PRESSURE IS THEN EXPECTED TO MOVE EAST FROM LAKE HURON...SKIRTING THE U.S.-CANADA BORDER. THE LOW SHOULD BRING A COLD FRONT THROUGH THE REGION ON WEDNESDAY. FOR NOW HAVE STUCK WITH CHANCE POPS DURING THE DAYTIME. THE FRONT SHOULD DROP TEMPERATURES ABOUT 5 DEGREES FROM THE PREVIOUS DAYS READING. HIGH PRESSURE WILL THEN RETURN WEDNESDAY NIGHT AND REMAIN ACROSS THE SOUTHEASTERN UNITED STATES THURSDAY. ANOTHER CANADIAN LOW SHOULD SWEEP A SECOND COLD FRONT THROUGH THURSDAY NIGHT INTO FRIDAY. THIS SHOULD BRING AT LEAST A SLIGHT CHANCE OF SHOWERS DURING THAT TIME PERIOD. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... EXPECT BROKEN LOW VFR CIGS IN DIURNAL CUMULUS THIS AFTERNOON...WITH SW GUSTS UP TO 15-20 KTS POSSIBLE. BY SUNSET STRATUS DECK SHOULD BE MOVING IN FROM THE WEST. THE STRATUS SHOULD PROVIDE VFR CEILINGS...EVENTUALLY DROPPING TO MVFR CIGS AS RAIN MOVES IN AROUND MIDNIGHT. DROPPED CIGS DOWN TO 1KFT AT FKL AND DUJ...BUT NOT ENOUGH CONFIDENCE TO GO IFR AT THIS POINT. WITH RAIN EXPECTED TO FALL PRIMARILY BEHIND THE COLD FRONT...EXPECT WIND SHIFT BEFORE RAIN BEGINS TO FALL. WINDS WILL SHIFT TO THE WEST AND INCREASE AS WIDESPREAD RAIN ENDS SATURDAY MORNING...WITH CIGS REMAINING AT A VFR LEVEL. .OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/... WIDESPREAD LOW VFR/HIGH MVFR CIGS CAN BE EXPECTED ALONG WITH SCATTERED SHOWERS SATURDAY NIGHT INTO SUNDAY. VFR CAN BE EXPECTED SUNDAY NIGHT THROUGH TUESDAY NIGHT BEFORE A COLD FRONT BRINGS POSSIBLE RESTRICTIONS IN SHOWERS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1205 PM EDT FRI OCT 5 2012 .SYNOPSIS... A CANADIAN COLD FRONT...WILL MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY TONIGHT...AND BRING SHOWERS AND MUCH COOLER TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY/... JUDGING FROM BLEND OF RECENT RADAR AND SATELLITE DATA...EXPECT SKIES TO REMAIN FAIRLY SUNNY THIS AFTERNOON. SURFACE DATA SHOWS TEMPERATURES CORRESPONDINGLY CLIMBING...SO HAVE CONTINUED FORECAST OF HIGHS THIS AFTERNOON GENERALLY 10 DEGREES WARMER THAN NORMAL...WHICH CONCURS WITH RECENT GFS LAMP AND HRRR MODEL OUTPUT. PER BLEND OF RECENT HIGH-RESOLUTION MODEL OUTPUT...PARTICULARLY WRF-NMM AND WRF-ARW...SHOW COLD ANAFRONTAL BAND OF SHOWERS PASSING SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY...MAINLY LATE TONIGHT INTO SATURDAY MORNING. FORECASTED TEMPERATURES...PER RECENT GFS AND NAM MOS...TO BECOME NOTICEABLY COLDER WITH LOWS TONIGHT NEAR NORMAL BUT HIGHS SATURDAY ABOUT 10 DEGREES COLDER THAN NORMAL. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... FRONT WILL CONTINUE ITS PROGRESSION ACROSS THE REGION BRINGING A GOOD CHANCE FOR RAIN THROUGH SATURDAY AFTERNOON. MODELS CONTINUE TO STALL THE FRONT SOMEWHERE ALONG THE MASON-DIXON LINE SATURDAY NIGHT BEFORE ANOTHER SHORTWAVE FINALLY PUSHES IT COMPLETELY SOUTH AND EAST. DECIDED TO CUT BACK POPS FOR THE SATURDAY NIGHT PERIOD THOUGH SOME POST FRONTAL SHOWERS COULD BE POSSIBLE IN NORTHWEST FLOW AND COOLING 850 TEMPERATURES. THE NEWEST MODEL RUNS ARE STARTING TO AGREE BETTER ON STRONGER SECONDARY SHORTWAVE EXPECTED TO CROSS THE OHIO VALLEY SUNDAY. THE ECMWF IS THE SLOWEST AND FURTHER NORTH WITH THE EXTENT OF PRECIP BUT EVEN WITH THE MORE SOUTHERLY GFS...NORTHWESTERLY FLOW BEHIND THE WAVE WOULD ONCE AGAIN BRING PRECIPITATION FOR MUCH OF THE AREA SUNDAY AFTERNOON. WILL KEEP CHANCE POPS FOR MUCH OF THE AREA WITH LIKELYS ON THE RIDGES. WEST/NORTHWEST UPPER LEVEL FLOW WILL PERSIST AFTER PASSAGE OF THE SHORTWAVE MAINTAINING THE CHANCE FOR SHOWERS AND EVEN A FEW SNOW SHOWERS IN THE HIGHER ELEVATIONS AND POINTS NORTH OF I-80 SUNDAY NIGHT AS 850HPA TEMPERATURES REMAIN AT -2C. STRONG COLD ADVECTION WITH THE PASSAGE OF THE FRONT AND SECONDARY SHORTWAVE WILL KEEP TEMPERATURES 5-10 DEGREES BELOW NORMAL THROUGH MONDAY. HIGH PRESSURE RIDGE AND BACKING WINDS WILL CUT OFF PRECIPITATION LATE SUNDAY NIGHT BRINGING THE POSSIBILITY OF A FREEZE IN SOME COUNTIES BY DAYBREAK. BUT...WITH UNCERTAINTY IN THE AMOUNT OF CLOUD COVER WILL LEAVE OUT MENTION IN FORECAST FOR NOW. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL REMAIN IN CONTROL TUESDAY...HELPING TO MODERATE TEMPERATURES TO CLOSER TO NORMAL VALUES. A SOUTHEASTBOUND CANADIAN COLD FRONT WILL PROVIDE A CHANCE OF SHOWERS TUESDAY NIGHT AND WEDNESDAY. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... VFR IS FORECAST THROUGH THIS AFTN AS SWLY FLOW DVLPS IN ADVN OF A CDFNT SLOWLY MOVING ACRS THE MIDWEST. .OUTLOOK.../TONIGHT THROUGH TUESDAY/... RESTRICTION POTENTIAL WL INCRS ON THIS EVE AS THE FRONT AND SHRA MOVE OVR THE UPR OH VALLEY REGION. WIDESPREAD MVFR STRATOCU AND PERIODIC SHRA CAN BE EXPECTED IN THE STRONG COLD ADVCTN REGIME BEHIND THE FRONT. VFR IS EXPECTED TO RTN WITH MONDAY HIGH PRES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1256 PM EDT FRI OCT 5 2012 .AVIATION... //DISCUSSION... SHALLOW POST FRONTAL COLD AIR ADVECTION LED TO THE DEVELOPMENT OF SOME MVFR BASED STRATUS THIS MORNING. THERE IS ENOUGH DRY AIR MIXING INTO THE INVERSION THAT THESE CLOUDS HAVE BEEN DECREASING IN COVERAGE...WHILE CONTINUED LOW LEVEL COLD AIR ADVECTION AND DAYTIME HEATING LIFT INVERSION BASES. A REGION OF SHOWERS ACROSS NORTH CENTRAL IL AND SRN IOWA WILL LIFT INTO SE MI THIS AFTERNOON... PRIMARILY AFTER 21Z. THIS FORCING SHOULD PERSIST THROUGH ROUGHLY 03Z BEFORE MOVING OFF TO THE EAST. PATCHES OF STRATO CU SHOULD PERSIST WELL THROUGH THE NIGHT UNDER CONTINUED LOW LEVEL COLD AIR ADVECTION. THE INCREASING DEPTH OF COLD AIR SHOULD HOWEVER KEEP BASES ABOVE 3000 FT. FOR DTW...AT LEAST SOME PATCHES OF RAIN ARE EXPECTED TO TRAVERSE METRO THIS EVENING. BEING A LITTLE CLOSER TO THE SFC COLD FRONT...INVERSION BASES AND THUS CEILING HEIGHTS WILL LIKELY BE A TOUCH LOWER THAN LOCATIONS FARTHER NORTH...POSSIBLY FALLING IN THE 3500 TO 4500 FT RANGE. CONFIDENCE ON CEILING HEIGHTS HOWEVER IS RATHER LOW GIVEN SOME ONGOING ENTRAINMENT OF DRY AIR. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FT TODAY AND TONIGHT. && .PREV DISCUSSION...ISSUED 1040 AM EDT FRI OCT 5 2012 UPDATE... AS OF 14Z...THE POST FRONTAL SHOWERS/THUNDERSTORMS EXTEND FROM S CNTL MO TO W CNTL LAKE ERIE. THE SHOWERS HAVE REMAINED SOUTH OF THE FORECAST AREA THIS MORNING AND RECENT RADAR TRENDS SUGGEST THE FORECAST AREA WILL REMAIN DRY THROUGH AT LEAST EARLY AFTERNOON. THE AMOUNT OF CONVECTION ALONG THE LOWER LEVELS OF THE FRONTAL SLOPE /ROUGHLY IN THE 925-850MB LAYER/ HAS BEEN MORE EXTENSIVE THAN EARLIER MODEL SOLUTIONS SUGGESTED DUE IN PART TO THE DEEP LAYER OF CONVECTIVE INSTABILITY IN THIS REGION. THUS THE MID LEVEL PORTIONS OF THE FRONT /WHICH EXTEND ACROSS SE MI/ HAVE THUS FAR BEEN INACTIVE. SATELLITE DATA IS HOWEVER SHOWING A MID LEVEL IMPULSE ROTATING INTO IOWA...FORECAST TO LIFT INTO LOWER MI THIS EVENING. THE APPROACH OF THIS WAVE ALONG WITH AN INTENSIFICATION OF AN UPPER LEVEL JET STREAK ADVANCING ACROSS THE NRN GREAT LAKES THIS AFTERNOON SHOULD ENHANCE FRONTOGENESIS ALONG THE ELEVATED FRONT /850-700MB LAYER/ DRAPED ACROSS SE MI. THIS FORCING IS NOT EXPECTED TO ARRIVE IN SE MI UNTIL 21Z AND SHOULD PERSIST INTO AT LEAST 03Z. WHILE THE BETTER CHANCES OF SHOWERS WILL OCCUR ALONG AND SOUTH OF A BAD AXE TO OWOSSO LINE...THERE IS A POTENTIAL THAT THE ELEVATED FRONT WILL BECOME MORE ACTIVE FARTHER NORTH...WHICH WILL SUPPORT ADDING AT LEAST A CHANCE OF LATE DAY SHOWERS TO THE TRI CITIES. WILL BE UPDATING THE FORECAST TO REFLECT THESE CHANGES. MEANWHILE...STRATO CU HAS BEEN DEVELOPING ACROSS SRN MI THIS MORNING. THE 12Z DTX SOUNDING SHOWED A FAIRLY DEEP INVERSION BASED NEAR 900MB...WITH AMPLE INSTABILITY BELOW TO ALLOW ENHANCEMENT TO THE CLOUD FIELD OFF LAKE MICHIGAN. THIS WILL SUPPORT BOOSTING CLOUD COVER A BIT AND KNOCKING A DEGREE OR TWO OFF AFTERNOON HIGHS. THE UPDATED ZFP AND GRIDS WILL BE ISSUED SHORTLY. PREV DISCUSSION...ISSUED 356 AM EDT FRI OCT 5 2012 SHORT TERM...TODAY AND TONIGHT NOW THAT THE SURFACE COLD FRONT HAS CLEARED THE AREA, MODERATE COLD ADVECTION HAS BEGUN AND IS FORECAST TO CONTINUE WITH 850MB TEMPERATURES FALLING TO SLIGHTLY BELOW ZERO BY 06Z TONIGHT. THE MOST NOTEWORTHY CHANGE MADE TO TODAY`S FORECAST PACKAGE WAS TO TREND TODAY`S HIGH TEMPERATURES DOWNWARD A COUPLE OF DEGREES. ALL LOCATIONS STAND A GOOD CHANCE TO REMAIN IN THE 50S FOR THE BALANCE OF THE DAY AS EARLY OCTOBER DIURNAL HEATING WILL HAVE TO CONTEND WITH NOT ONLY WITH ONGOING COLD ADVECTION, BUT ALSO WIDESPREAD MID AND UPPER CLOUDS. IN ADDITION, UPSTREAM LOCATIONS THAT SPENT THE DAYTIME HOURS THURSDAY IN THE POST-FRONTAL ENVIRONMENT GENERALLY ROSE INTO THE LOW 50S. AFTER GIVING CONSIDERATION TO THE HEAT CONTRIBUTION FROM LAKE MICHIGAN, WHERE LAKE SFC TEMPS REMAIN IN THE LOW 60S, HIGHS FOR TODAY WERE GIVEN A DOWNWARD ADJUSTMENT INTO THE 55-58 DEGREE RANGE. A FEW 60S STILL CAN`T BE RULED OUT SHOULD CLOUDS BREAK DURING PEAK HEATING, MOST LIKELY NORTH OF M-59. THE OTHER FORECAST ISSUE FOR TODAY IS THE PLACEMENT AND DURATION OF A BAND OF SHOWERS THAT IS CURRENTLY TAKING SHAPE OVER MO/IL. WATER VAPOR IMAGERY SHOWS AN ENERGETIC ZONAL FLOW ACROSS THE CENTRAL U.S. WITH EMBEDDED LOW AMPLITUDE SHORTWAVES PROPAGATING ACROSS THE PLAINS STATES. SHOWER COVERAGE IS EXPANDING AHEAD OF THIS ENERGY AND IN ASSOCIATION WITH A DEVELOPING FGEN RESPONSE UNDER THE RIGHT ENTRANCE OF A STRENGTHENING 90KT JET STREAK. THE 00Z GUIDANCE, IN PARTICULAR THE NAM AND RECENT 3-KM HRRR SIMULATIONS, LOOK SOLID IN THEIR REPRESENTATION OF THE DEVELOPING FRONTAL CIRCULATION AND ASSOCIATED PRECIPITATION COVERAGE. FOR NOW, THE ONLY COMPLAINT IS THAT THE RESPONSE WITHIN THE LOW STATIC STABILITY ENVIRONMENT LEADING THE ARRIVAL OF THE JET CORE LOOKS HEALTHY, SO LEANED TOWARD AN EARLIER 12-13Z ARRIVAL TIME FOR SOUTHERN AREAS. THE NORTH SIDE OF THE PRECIP SHIELD WILL INITIALLY CARRY THE SHARP CUTOFF EVIDENT ON THE REGIONAL RADAR MOSAIC INTO THE AREA, CASTING SOME UNCERTAINTY ON ITS NORTHWARD EXTENT AS IT STRADDLES THE METRO DETROIT AREA INTO THE AFTERNOON. HOWEVER, ADDITIONAL NORTHWARD EXPANSION SEEMS PROBABLE THIS AFTERNOON AS THE POTENT SHORTWAVE ENERGY OVER ID/WY AT 07Z ACCELERATES TOWARD THE AREA LATER TODAY. LAKE CLOUDS WILL THEN BUILD INTO THE AREA LATE TONIGHT COINCIDENT WITH THE APPROACH OF THE UPPER TROUGH AXIS AND H85-SFC DELTA T VALUES PLUMMETING TO 20C OVER LM. THE STAGE WILL THEN BE SET FOR A COLD START TO SATURDAY MORNING AS LOW TEMPS DIP INTO THE MID TO UPPER 30S UNDERNEATH INCREASING BOUNDARY LAYER SKY COVER. LONG TERM...SATURDAY THROUGH THURSDAY AS UPPER LOW SHIFTS JUST NORTH OF LAKE SUPERIOR IS PULLED NORTHEAST INTO BROADER HUDSON BAY VORTEX...UPPER TROUGH AXIS WILL SWING ACROSS LOWER MICHIGAN AND BRING A SECOND SHOT OF COLD AIR INTO THE AREA ON SATURDAY. WITH H85 TEMPERATURES FALLING SOLIDLY BELOW 0C...EXPECT HIGH TEMPERATURES TO REMAIN BETWEEN 50 AND 55. WHILE BEST LIFT AND FORCING WITH THE VORTICITY CENTER ALONG THIS TROUGH WILL REMAIN TO THE NORTH OF THE AREA...THERE WILL BE A SMALL CHANCE OF SHOWERS IN THE 20-30% RANGE AS WRAPAROUND MOISTURE BRUSHES THE AREA AND LAKE EFFECT ACTIVITY BEGINS TO EXPAND IN THE COLDER AIR. AFTER ANOTHER DAY WITH HIGH TEMPERATURES AOB 55F ON SUNDAY (WITH EARLY MORNING TEMPERATURES MOST LIKELY REACHING FREEZING IN SOME LOCATIONS)...THE NEXT STRONG SHORTWAVE PIVOTING THROUGH THE NORTHERN GREAT LAKES AROUND THE HUDSON VORTEX WILL BRING A MODERATING TREND IN THE MONDAY AND TUESDAY TIME FRAME AS SOUTHWEST FLOW BECOMES ESTABLISHED IN ADVANCE OF THE NEXT STRONG COLD FRONT WHICH WILL SHIFT INTO THE AREA AS THIS SECOND NORTHERN STREAM STORM SYSTEM WRAPS NORTHEAST INTO THE AFOREMENTIONED VORTEX. TEMPERATURES WILL CLIMB WELL INTO THE 50S ON MONDAY AND TO 60 OR BETTER ON TUESDAY AS THE ARRIVAL OF THIS COLD FRONT IS DELAYED SLIGHTLY AS LOW PRESSURE RIPPLES UP ALONG IT. THIS SOUTHERN STREAM LOW PRESSURE WILL BRING THE BEST CHANCE OF RAINFALL IN THE EXTENDED PORTION OF THE FORECAST AS STRONG FORCING SHIFTS THROUGH THE AREA WITH THIS PASSAGE OF THIS SYSTEM TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING...WITH ONLY MINOR LAKE EFFECT ACTIVITY EXPECTED LATER WEDNESDAY INTO THURSDAY SOUTHEAST OF LAKE HURON. TEMPERATURES WILL COOL BACK INTO THE MID 50S ON WEDNESDAY...BUT WITH NORTHERN STREAM SHORTWAVE TAKING A WESTERLY TRACK NORTH OF THE GREAT LAKES...THE COLDEST AIR WITH THIS SYSTEM WILL REMAIN OVER CANADA AND EXPECT TEMPERATURES TO REBOUND TO THE UPPER 50S TO AROUND 60 BY THURSDAY. MARINE... A FRESH WEST-SOUTHWEST BREEZE WILL GUST INTO THE 25 TO 30 KNOT RANGE TODAY AS A COOL AND UNSTABLE AIRMASS OVERSPREADS AREA WATERS. A FEW GUSTS TO LOW END GALE FORCE WILL BE POSSIBLE FROM OUTER SAGINAW BAY INTO CENTRAL LAKE HURON THIS AFTERNOON...BUT NO ORGANIZED OR WIDESPREAD GALES ARE EXPECTED. WINDS WILL GRADUALLY EASE BY LATE FRIDAY NIGHT BUT WAVES WILL REMAIN REMAIN ELEVATED INTO SATURDAY MORNING. ALL SMALL CRAFT ADVISORIES THEREFORE REMAIN IN EFFECT FOR SAGINAW BAY AND THE NEARSHORE FROM PORT AUSTIN TO HARBOR BEACH UNTIL SATURDAY MORNING. A RENEWED SURGE OF GUSTY WINDS WILL DEVELOP AHEAD OF ANOTHER PUSH OF COLD AIR ON SATURDAY. A BRIEF REPRIEVE CAN BE EXPECTED ON SUNDAY AS SURFACE HIGH PRESSURE SLIDES ACROSS THE AREA...BUT UNSETTLED CONDITIONS WILL QUICKLY REDEVELOP AS THE SURFACE PRESSURE GRADIENT STRENGTHENS EARLY NEXT WEEK. SOUTH WINDS WILL INCREASE TO 20 TO 25 KNOTS BY LATE MONDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 8 AM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....SC UPDATE.......SC SHORT TERM...JVC LONG TERM....DG MARINE.......JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1040 AM EDT FRI OCT 5 2012 .UPDATE... AS OF 14Z...THE POST FRONTAL SHOWERS/THUNDERSTORMS EXTEND FROM S CNTL MO TO W CNTL LAKE ERIE. THE SHOWERS HAVE REMAINED SOUTH OF THE FORECAST AREA THIS MORNING AND RECENT RADAR TRENDS SUGGEST THE FORECAST AREA WILL REMAIN DRY THROUGH AT LEAST EARLY AFTERNOON. THE AMOUNT OF CONVECTION ALONG THE LOWER LEVELS OF THE FRONTAL SLOPE /ROUGHLY IN THE 925-850MB LAYER/ HAS BEEN MORE EXTENSIVE THAN EARLIER MODEL SOLUTIONS SUGGESTED DUE IN PART TO THE DEEP LAYER OF CONVECTIVE INSTABILITY IN THIS REGION. THUS THE MID LEVEL PORTIONS OF THE FRONT /WHICH EXTEND ACROSS SE MI/ HAVE THUS FAR BEEN INACTIVE. SATELLITE DATA IS HOWEVER SHOWING A MID LEVEL IMPULSE ROTATING INTO IOWA...FORECAST TO LIFT INTO LOWER MI THIS EVENING. THE APPROACH OF THIS WAVE ALONG WITH AN INTENSIFICATION OF AN UPPER LEVEL JET STREAK ADVANCING ACROSS THE NRN GREAT LAKES THIS AFTERNOON SHOULD ENHANCE FRONTOGENESIS ALONG THE ELEVATED FRONT /850-700MB LAYER/ DRAPED ACROSS SE MI. THIS FORCING IS NOT EXPECTED TO ARRIVE IN SE MI UNTIL 21Z AND SHOULD PERSIST INTO AT LEAST 03Z. WHILE THE BETTER CHANCES OF SHOWERS WILL OCCUR ALONG AND SOUTH OF A BAD AXE TO OWOSSO LINE...THERE IS A POTENTIAL THAT THE ELEVATED FRONT WILL BECOME MORE ACTIVE FARTHER NORTH...WHICH WILL SUPPORT ADDING AT LEAST A CHANCE OF LATE DAY SHOWERS TO THE TRI CITIES. WILL BE UPDATING THE FORECAST TO REFLECT THESE CHANGES. MEANWHILE...STRATO CU HAS BEEN DEVELOPING ACROSS SRN MI THIS MORNING. THE 12Z DTX SOUNDING SHOWED A FAIRLY DEEP INVERSION BASED NEAR 900MB...WITH AMPLE INSTABILITY BELOW TO ALLOW ENHANCEMENT TO THE CLOUD FIELD OFF LAKE MICHIGAN. THIS WILL SUPPORT BOOSTING CLOUD COVER A BIT AND KNOCKING A DEGREE OR TWO OFF AFTERNOON HIGHS. THE UPDATED ZFP AND GRIDS WILL BE ISSUED SHORTLY. && .AVIATION...ISSUED 654 AM EDT FRI OCT 5 2012 //DISCUSSION... WEST WINDS OF 10 TO 15 KNOTS WILL OCCASIONALLY GUST TO 20 KNOTS TODAY, ESPECIALLY ACROSS NORTHERN AREAS WHERE DIURNAL HEATING IS EXPECTED TO BE STRONGER. SHOWERS DEVELOPING UPSTREAM WILL SPREAD INTO THE AREA THROUGH THE MORNING, REACHING THE DETROIT AIRFIELDS BY EARLY THIS AFTERNOON. CEILINGS STAND A GOOD CHANCE OF FALLING BELOW 5000 FEET AND POSSIBLY INTO THE MVFR RANGE WITH THIS ACTIVITY. CONDITIONS WILL IMPROVE AS THE SHOWERS SHIFT EAST LATE THIS EVENING. DEVELOPING NORTHWEST FLOW WILL RESULT IN LAKE CLOUD DEVELOPMENT FOR SATURDAY. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FEET BY LATE THIS MORNING AND AGAIN BY LATE SATURDAY MORNING. && .PREV DISCUSSION...ISSUED 356 AM EDT FRI OCT 5 2012 SHORT TERM...TODAY AND TONIGHT NOW THAT THE SURFACE COLD FRONT HAS CLEARED THE AREA, MODERATE COLD ADVECTION HAS BEGUN AND IS FORECAST TO CONTINUE WITH 850MB TEMPERATURES FALLING TO SLIGHTLY BELOW ZERO BY 06Z TONIGHT. THE MOST NOTEWORTHY CHANGE MADE TO TODAY`S FORECAST PACKAGE WAS TO TREND TODAY`S HIGH TEMPERATURES DOWNWARD A COUPLE OF DEGREES. ALL LOCATIONS STAND A GOOD CHANCE TO REMAIN IN THE 50S FOR THE BALANCE OF THE DAY AS EARLY OCTOBER DIURNAL HEATING WILL HAVE TO CONTEND WITH NOT ONLY WITH ONGOING COLD ADVECTION, BUT ALSO WIDESPREAD MID AND UPPER CLOUDS. IN ADDITION, UPSTREAM LOCATIONS THAT SPENT THE DAYTIME HOURS THURSDAY IN THE POST-FRONTAL ENVIRONMENT GENERALLY ROSE INTO THE LOW 50S. AFTER GIVING CONSIDERATION TO THE HEAT CONTRIBUTION FROM LAKE MICHIGAN, WHERE LAKE SFC TEMPS REMAIN IN THE LOW 60S, HIGHS FOR TODAY WERE GIVEN A DOWNWARD ADJUSTMENT INTO THE 55-58 DEGREE RANGE. A FEW 60S STILL CAN`T BE RULED OUT SHOULD CLOUDS BREAK DURING PEAK HEATING, MOST LIKELY NORTH OF M-59. THE OTHER FORECAST ISSUE FOR TODAY IS THE PLACEMENT AND DURATION OF A BAND OF SHOWERS THAT IS CURRENTLY TAKING SHAPE OVER MO/IL. WATER VAPOR IMAGERY SHOWS AN ENERGETIC ZONAL FLOW ACROSS THE CENTRAL U.S. WITH EMBEDDED LOW AMPLITUDE SHORTWAVES PROPAGATING ACROSS THE PLAINS STATES. SHOWER COVERAGE IS EXPANDING AHEAD OF THIS ENERGY AND IN ASSOCIATION WITH A DEVELOPING FGEN RESPONSE UNDER THE RIGHT ENTRANCE OF A STRENGTHENING 90KT JET STREAK. THE 00Z GUIDANCE, IN PARTICULAR THE NAM AND RECENT 3-KM HRRR SIMULATIONS, LOOK SOLID IN THEIR REPRESENTATION OF THE DEVELOPING FRONTAL CIRCULATION AND ASSOCIATED PRECIPITATION COVERAGE. FOR NOW, THE ONLY COMPLAINT IS THAT THE RESPONSE WITHIN THE LOW STATIC STABILITY ENVIRONMENT LEADING THE ARRIVAL OF THE JET CORE LOOKS HEALTHY, SO LEANED TOWARD AN EARLIER 12-13Z ARRIVAL TIME FOR SOUTHERN AREAS. THE NORTH SIDE OF THE PRECIP SHIELD WILL INITIALLY CARRY THE SHARP CUTOFF EVIDENT ON THE REGIONAL RADAR MOSAIC INTO THE AREA, CASTING SOME UNCERTAINTY ON ITS NORTHWARD EXTENT AS IT STRADDLES THE METRO DETROIT AREA INTO THE AFTERNOON. HOWEVER, ADDITIONAL NORTHWARD EXPANSION SEEMS PROBABLE THIS AFTERNOON AS THE POTENT SHORTWAVE ENERGY OVER ID/WY AT 07Z ACCELERATES TOWARD THE AREA LATER TODAY. LAKE CLOUDS WILL THEN BUILD INTO THE AREA LATE TONIGHT COINCIDENT WITH THE APPROACH OF THE UPPER TROUGH AXIS AND H85-SFC DELTA T VALUES PLUMMETING TO 20C OVER LM. THE STAGE WILL THEN BE SET FOR A COLD START TO SATURDAY MORNING AS LOW TEMPS DIP INTO THE MID TO UPPER 30S UNDERNEATH INCREASING BOUNDARY LAYER SKY COVER. LONG TERM...SATURDAY THROUGH THURSDAY AS UPPER LOW SHIFTS JUST NORTH OF LAKE SUPERIOR IS PULLED NORTHEAST INTO BROADER HUDSON BAY VORTEX...UPPER TROUGH AXIS WILL SWING ACROSS LOWER MICHIGAN AND BRING A SECOND SHOT OF COLD AIR INTO THE AREA ON SATURDAY. WITH H85 TEMPERATURES FALLING SOLIDLY BELOW 0C...EXPECT HIGH TEMPERATURES TO REMAIN BETWEEN 50 AND 55. WHILE BEST LIFT AND FORCING WITH THE VORTICITY CENTER ALONG THIS TROUGH WILL REMAIN TO THE NORTH OF THE AREA...THERE WILL BE A SMALL CHANCE OF SHOWERS IN THE 20-30% RANGE AS WRAPAROUND MOISTURE BRUSHES THE AREA AND LAKE EFFECT ACTIVITY BEGINS TO EXPAND IN THE COLDER AIR. AFTER ANOTHER DAY WITH HIGH TEMPERATURES AOB 55F ON SUNDAY (WITH EARLY MORNING TEMPERATURES MOST LIKELY REACHING FREEZING IN SOME LOCATIONS)...THE NEXT STRONG SHORTWAVE PIVOTING THROUGH THE NORTHERN GREAT LAKES AROUND THE HUDSON VORTEX WILL BRING A MODERATING TREND IN THE MONDAY AND TUESDAY TIME FRAME AS SOUTHWEST FLOW BECOMES ESTABLISHED IN ADVANCE OF THE NEXT STRONG COLD FRONT WHICH WILL SHIFT INTO THE AREA AS THIS SECOND NORTHERN STREAM STORM SYSTEM WRAPS NORTHEAST INTO THE AFOREMENTIONED VORTEX. TEMPERATURES WILL CLIMB WELL INTO THE 50S ON MONDAY AND TO 60 OR BETTER ON TUESDAY AS THE ARRIVAL OF THIS COLD FRONT IS DELAYED SLIGHTLY AS LOW PRESSURE RIPPLES UP ALONG IT. THIS SOUTHERN STREAM LOW PRESSURE WILL BRING THE BEST CHANCE OF RAINFALL IN THE EXTENDED PORTION OF THE FORECAST AS STRONG FORCING SHIFTS THROUGH THE AREA WITH THIS PASSAGE OF THIS SYSTEM TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING...WITH ONLY MINOR LAKE EFFECT ACTIVITY EXPECTED LATER WEDNESDAY INTO THURSDAY SOUTHEAST OF LAKE HURON. TEMPERATURES WILL COOL BACK INTO THE MID 50S ON WEDNESDAY...BUT WITH NORTHERN STREAM SHORTWAVE TAKING A WESTERLY TRACK NORTH OF THE GREAT LAKES...THE COLDEST AIR WITH THIS SYSTEM WILL REMAIN OVER CANADA AND EXPECT TEMPERATURES TO REBOUND TO THE UPPER 50S TO AROUND 60 BY THURSDAY. MARINE... A FRESH WEST-SOUTHWEST BREEZE WILL GUST INTO THE 25 TO 30 KNOT RANGE TODAY AS A COOL AND UNSTABLE AIRMASS OVERSPREADS AREA WATERS. A FEW GUSTS TO LOW END GALE FORCE WILL BE POSSIBLE FROM OUTER SAGINAW BAY INTO CENTRAL LAKE HURON THIS AFTERNOON...BUT NO ORGANIZED OR WIDESPREAD GALES ARE EXPECTED. WINDS WILL GRADUALLY EASE BY LATE FRIDAY NIGHT BUT WAVES WILL REMAIN REMAIN ELEVATED INTO SATURDAY MORNING. ALL SMALL CRAFT ADVISORIES THEREFORE REMAIN IN EFFECT FOR SAGINAW BAY AND THE NEARSHORE FROM PORT AUSTIN TO HARBOR BEACH UNTIL SATURDAY MORNING. A RENEWED SURGE OF GUSTY WINDS WILL DEVELOP AHEAD OF ANOTHER PUSH OF COLD AIR ON SATURDAY. A BRIEF REPRIEVE CAN BE EXPECTED ON SUNDAY AS SURFACE HIGH PRESSURE SLIDES ACROSS THE AREA...BUT UNSETTLED CONDITIONS WILL QUICKLY REDEVELOP AS THE SURFACE PRESSURE GRADIENT STRENGTHENS EARLY NEXT WEEK. SOUTH WINDS WILL INCREASE TO 20 TO 25 KNOTS BY LATE MONDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 8 AM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SC AVIATION.....DG SHORT TERM...JVC LONG TERM....DG MARINE.......JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
654 AM EDT FRI OCT 5 2012 .AVIATION... //DISCUSSION... WEST WINDS OF 10 TO 15 KNOTS WILL OCCASIONALLY GUST TO 20 KNOTS TODAY, ESPECIALLY ACROSS NORTHERN AREAS WHERE DIURNAL HEATING IS EXPECTED TO BE STRONGER. SHOWERS DEVELOPING UPSTREAM WILL SPREAD INTO THE AREA THROUGH THE MORNING, REACHING THE DETROIT AIRFIELDS BY EARLY THIS AFTERNOON. CEILINGS STAND A GOOD CHANCE OF FALLING BELOW 5000 FEET AND POSSIBLY INTO THE MVFR RANGE WITH THIS ACTIVITY. CONDITIONS WILL IMPROVE AS THE SHOWERS SHIFT EAST LATE THIS EVENING. DEVELOPING NORTHWEST FLOW WILL RESULT IN LAKE CLOUD DEVELOPMENT FOR SATURDAY. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FEET BY LATE THIS MORNING AND AGAIN BY LATE SATURDAY MORNING. && .PREV DISCUSSION...ISSUED 356 AM EDT FRI OCT 5 2012 SHORT TERM...TODAY AND TONIGHT NOW THAT THE SURFACE COLD FRONT HAS CLEARED THE AREA, MODERATE COLD ADVECTION HAS BEGUN AND IS FORECAST TO CONTINUE WITH 850MB TEMPERATURES FALLING TO SLIGHTLY BELOW ZERO BY 06Z TONIGHT. THE MOST NOTEWORTHY CHANGE MADE TO TODAY`S FORECAST PACKAGE WAS TO TREND TODAY`S HIGH TEMPERATURES DOWNWARD A COUPLE OF DEGREES. ALL LOCATIONS STAND A GOOD CHANCE TO REMAIN IN THE 50S FOR THE BALANCE OF THE DAY AS EARLY OCTOBER DIURNAL HEATING WILL HAVE TO CONTEND WITH NOT ONLY WITH ONGOING COLD ADVECTION, BUT ALSO WIDESPREAD MID AND UPPER CLOUDS. IN ADDITION, UPSTREAM LOCATIONS THAT SPENT THE DAYTIME HOURS THURSDAY IN THE POST-FRONTAL ENVIRONMENT GENERALLY ROSE INTO THE LOW 50S. AFTER GIVING CONSIDERATION TO THE HEAT CONTRIBUTION FROM LAKE MICHIGAN, WHERE LAKE SFC TEMPS REMAIN IN THE LOW 60S, HIGHS FOR TODAY WERE GIVEN A DOWNWARD ADJUSTMENT INTO THE 55-58 DEGREE RANGE. A FEW 60S STILL CAN`T BE RULED OUT SHOULD CLOUDS BREAK DURING PEAK HEATING, MOST LIKELY NORTH OF M-59. THE OTHER FORECAST ISSUE FOR TODAY IS THE PLACEMENT AND DURATION OF A BAND OF SHOWERS THAT IS CURRENTLY TAKING SHAPE OVER MO/IL. WATER VAPOR IMAGERY SHOWS AN ENERGETIC ZONAL FLOW ACROSS THE CENTRAL U.S. WITH EMBEDDED LOW AMPLITUDE SHORTWAVES PROPAGATING ACROSS THE PLAINS STATES. SHOWER COVERAGE IS EXPANDING AHEAD OF THIS ENERGY AND IN ASSOCIATION WITH A DEVELOPING FGEN RESPONSE UNDER THE RIGHT ENTRANCE OF A STRENGTHENING 90KT JET STREAK. THE 00Z GUIDANCE, IN PARTICULAR THE NAM AND RECENT 3-KM HRRR SIMULATIONS, LOOK SOLID IN THEIR REPRESENTATION OF THE DEVELOPING FRONTAL CIRCULATION AND ASSOCIATED PRECIPITATION COVERAGE. FOR NOW, THE ONLY COMPLAINT IS THAT THE RESPONSE WITHIN THE LOW STATIC STABILITY ENVIRONMENT LEADING THE ARRIVAL OF THE JET CORE LOOKS HEALTHY, SO LEANED TOWARD AN EARLIER 12-13Z ARRIVAL TIME FOR SOUTHERN AREAS. THE NORTH SIDE OF THE PRECIP SHIELD WILL INITIALLY CARRY THE SHARP CUTOFF EVIDENT ON THE REGIONAL RADAR MOSAIC INTO THE AREA, CASTING SOME UNCERTAINTY ON ITS NORTHWARD EXTENT AS IT STRADDLES THE METRO DETROIT AREA INTO THE AFTERNOON. HOWEVER, ADDITIONAL NORTHWARD EXPANSION SEEMS PROBABLE THIS AFTERNOON AS THE POTENT SHORTWAVE ENERGY OVER ID/WY AT 07Z ACCELERATES TOWARD THE AREA LATER TODAY. LAKE CLOUDS WILL THEN BUILD INTO THE AREA LATE TONIGHT COINCIDENT WITH THE APPROACH OF THE UPPER TROUGH AXIS AND H85-SFC DELTA T VALUES PLUMMETING TO 20C OVER LM. THE STAGE WILL THEN BE SET FOR A COLD START TO SATURDAY MORNING AS LOW TEMPS DIP INTO THE MID TO UPPER 30S UNDERNEATH INCREASING BOUNDARY LAYER SKY COVER. LONG TERM...SATURDAY THROUGH THURSDAY AS UPPER LOW SHIFTS JUST NORTH OF LAKE SUPERIOR IS PULLED NORTHEAST INTO BROADER HUDSON BAY VORTEX...UPPER TROUGH AXIS WILL SWING ACROSS LOWER MICHIGAN AND BRING A SECOND SHOT OF COLD AIR INTO THE AREA ON SATURDAY. WITH H85 TEMPERATURES FALLING SOLIDLY BELOW 0C...EXPECT HIGH TEMPERATURES TO REMAIN BETWEEN 50 AND 55. WHILE BEST LIFT AND FORCING WITH THE VORTICITY CENTER ALONG THIS TROUGH WILL REMAIN TO THE NORTH OF THE AREA...THERE WILL BE A SMALL CHANCE OF SHOWERS IN THE 20-30% RANGE AS WRAPAROUND MOISTURE BRUSHES THE AREA AND LAKE EFFECT ACTIVITY BEGINS TO EXPAND IN THE COLDER AIR. AFTER ANOTHER DAY WITH HIGH TEMPERATURES AOB 55F ON SUNDAY (WITH EARLY MORNING TEMPERATURES MOST LIKELY REACHING FREEZING IN SOME LOCATIONS)...THE NEXT STRONG SHORTWAVE PIVOTING THROUGH THE NORTHERN GREAT LAKES AROUND THE HUDSON VORTEX WILL BRING A MODERATING TREND IN THE MONDAY AND TUESDAY TIME FRAME AS SOUTHWEST FLOW BECOMES ESTABLISHED IN ADVANCE OF THE NEXT STRONG COLD FRONT WHICH WILL SHIFT INTO THE AREA AS THIS SECOND NORTHERN STREAM STORM SYSTEM WRAPS NORTHEAST INTO THE AFOREMENTIONED VORTEX. TEMPERATURES WILL CLIMB WELL INTO THE 50S ON MONDAY AND TO 60 OR BETTER ON TUESDAY AS THE ARRIVAL OF THIS COLD FRONT IS DELAYED SLIGHTLY AS LOW PRESSURE RIPPLES UP ALONG IT. THIS SOUTHERN STREAM LOW PRESSURE WILL BRING THE BEST CHANCE OF RAINFALL IN THE EXTENDED PORTION OF THE FORECAST AS STRONG FORCING SHIFTS THROUGH THE AREA WITH THIS PASSAGE OF THIS SYSTEM TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING...WITH ONLY MINOR LAKE EFFECT ACTIVITY EXPECTED LATER WEDNESDAY INTO THURSDAY SOUTHEAST OF LAKE HURON. TEMPERATURES WILL COOL BACK INTO THE MID 50S ON WEDNESDAY...BUT WITH NORTHERN STREAM SHORTWAVE TAKING A WESTERLY TRACK NORTH OF THE GREAT LAKES...THE COLDEST AIR WITH THIS SYSTEM WILL REMAIN OVER CANADA AND EXPECT TEMPERATURES TO REBOUND TO THE UPPER 50S TO AROUND 60 BY THURSDAY. MARINE... A FRESH WEST-SOUTHWEST BREEZE WILL GUST INTO THE 25 TO 30 KNOT RANGE TODAY AS A COOL AND UNSTABLE AIRMASS OVERSPREADS AREA WATERS. A FEW GUSTS TO LOW END GALE FORCE WILL BE POSSIBLE FROM OUTER SAGINAW BAY INTO CENTRAL LAKE HURON THIS AFTERNOON...BUT NO ORGANIZED OR WIDESPREAD GALES ARE EXPECTED. WINDS WILL GRADUALLY EASE BY LATE FRIDAY NIGHT BUT WAVES WILL REMAIN REMAIN ELEVATED INTO SATURDAY MORNING. ALL SMALL CRAFT ADVISORIES THEREFORE REMAIN IN EFFECT FOR SAGINAW BAY AND THE NEARSHORE FROM PORT AUSTIN TO HARBOR BEACH UNTIL SATURDAY MORNING. A RENEWED SURGE OF GUSTY WINDS WILL DEVELOP AHEAD OF ANOTHER PUSH OF COLD AIR ON SATURDAY. A BRIEF REPRIEVE CAN BE EXPECTED ON SUNDAY AS SURFACE HIGH PRESSURE SLIDES ACROSS THE AREA...BUT UNSETTLED CONDITIONS WILL QUICKLY REDEVELOP AS THE SURFACE PRESSURE GRADIENT STRENGTHENS EARLY NEXT WEEK. SOUTH WINDS WILL INCREASE TO 20 TO 25 KNOTS BY LATE MONDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 8 AM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....DG SHORT TERM...JVC LONG TERM....DG MARINE.......JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
356 AM EDT FRI OCT 5 2012 .SHORT TERM...TODAY AND TONIGHT NOW THAT THE SURFACE COLD FRONT HAS CLEARED THE AREA, MODERATE COLD ADVECTION HAS BEGUN AND IS FORECAST TO CONTINUE WITH 850MB TEMPERATURES FALLING TO SLIGHTLY BELOW ZERO BY 06Z TONIGHT. THE MOST NOTEWORTHY CHANGE MADE TO TODAY`S FORECAST PACKAGE WAS TO TREND TODAY`S HIGH TEMPERATURES DOWNWARD A COUPLE OF DEGREES. ALL LOCATIONS STAND A GOOD CHANCE TO REMAIN IN THE 50S FOR THE BALANCE OF THE DAY AS EARLY OCTOBER DIURNAL HEATING WILL HAVE TO CONTEND WITH NOT ONLY WITH ONGOING COLD ADVECTION, BUT ALSO WIDESPREAD MID AND UPPER CLOUDS. IN ADDITION, UPSTREAM LOCATIONS THAT SPENT THE DAYTIME HOURS THURSDAY IN THE POST-FRONTAL ENVIRONMENT GENERALLY ROSE INTO THE LOW 50S. AFTER GIVING CONSIDERATION TO THE HEAT CONTRIBUTION FROM LAKE MICHIGAN, WHERE LAKE SFC TEMPS REMAIN IN THE LOW 60S, HIGHS FOR TODAY WERE GIVEN A DOWNWARD ADJUSTMENT INTO THE 55-58 DEGREE RANGE. A FEW 60S STILL CAN`T BE RULED OUT SHOULD CLOUDS BREAK DURING PEAK HEATING, MOST LIKELY NORTH OF M-59. THE OTHER FORECAST ISSUE FOR TODAY IS THE PLACEMENT AND DURATION OF A BAND OF SHOWERS THAT IS CURRENTLY TAKING SHAPE OVER MO/IL. WATER VAPOR IMAGERY SHOWS AN ENERGETIC ZONAL FLOW ACROSS THE CENTRAL U.S. WITH EMBEDDED LOW AMPLITUDE SHORTWAVES PROPAGATING ACROSS THE PLAINS STATES. SHOWER COVERAGE IS EXPANDING AHEAD OF THIS ENERGY AND IN ASSOCIATION WITH A DEVELOPING FGEN RESPONSE UNDER THE RIGHT ENTRANCE OF A STRENGTHENING 90KT JET STREAK. THE 00Z GUIDANCE, IN PARTICULAR THE NAM AND RECENT 3-KM HRRR SIMULATIONS, LOOK SOLID IN THEIR REPRESENTATION OF THE DEVELOPING FRONTAL CIRCULATION AND ASSOCIATED PRECIPITATION COVERAGE. FOR NOW, THE ONLY COMPLAINT IS THAT THE RESPONSE WITHIN THE LOW STATIC STABILITY ENVIRONMENT LEADING THE ARRIVAL OF THE JET CORE LOOKS HEALTHY, SO LEANED TOWARD AN EARLIER 12-13Z ARRIVAL TIME FOR SOUTHERN AREAS. THE NORTH SIDE OF THE PRECIP SHIELD WILL INITIALLY CARRY THE SHARP CUTOFF EVIDENT ON THE REGIONAL RADAR MOSAIC INTO THE AREA, CASTING SOME UNCERTAINTY ON ITS NORTHWARD EXTENT AS IT STRADDLES THE METRO DETROIT AREA INTO THE AFTERNOON. HOWEVER, ADDITIONAL NORTHWARD EXPANSION SEEMS PROBABLE THIS AFTERNOON AS THE POTENT SHORTWAVE ENERGY OVER ID/WY AT 07Z ACCELERATES TOWARD THE AREA LATER TODAY. LAKE CLOUDS WILL THEN BUILD INTO THE AREA LATE TONIGHT COINCIDENT WITH THE APPROACH OF THE UPPER TROUGH AXIS AND H85-SFC DELTA T VALUES PLUMMETING TO 20C OVER LM. THE STAGE WILL THEN BE SET FOR A COLD START TO SATURDAY MORNING AS LOW TEMPS DIP INTO THE MID TO UPPER 30S UNDERNEATH INCREASING BOUNDARY LAYER SKY COVER. && .LONG TERM...SATURDAY THROUGH THURSDAY AS UPPER LOW SHIFTS JUST NORTH OF LAKE SUPERIOR IS PULLED NORTHEAST INTO BROADER HUDSON BAY VORTEX...UPPER TROUGH AXIS WILL SWING ACROSS LOWER MICHIGAN AND BRING A SECOND SHOT OF COLD AIR INTO THE AREA ON SATURDAY. WITH H85 TEMPERATURES FALLING SOLIDLY BELOW 0C...EXPECT HIGH TEMPERATURES TO REMAIN BETWEEN 50 AND 55. WHILE BEST LIFT AND FORCING WITH THE VORTICITY CENTER ALONG THIS TROUGH WILL REMAIN TO THE NORTH OF THE AREA...THERE WILL BE A SMALL CHANCE OF SHOWERS IN THE 20-30% RANGE AS WRAPAROUND MOISTURE BRUSHES THE AREA AND LAKE EFFECT ACTIVITY BEGINS TO EXPAND IN THE COLDER AIR. AFTER ANOTHER DAY WITH HIGH TEMPERATURES AOB 55F ON SUNDAY (WITH EARLY MORNING TEMPERATURES MOST LIKELY REACHING FREEZING IN SOME LOCATIONS)...THE NEXT STRONG SHORTWAVE PIVOTING THROUGH THE NORTHERN GREAT LAKES AROUND THE HUDSON VORTEX WILL BRING A MODERATING TREND IN THE MONDAY AND TUESDAY TIME FRAME AS SOUTHWEST FLOW BECOMES ESTABLISHED IN ADVANCE OF THE NEXT STRONG COLD FRONT WHICH WILL SHIFT INTO THE AREA AS THIS SECOND NORTHERN STREAM STORM SYSTEM WRAPS NORTHEAST INTO THE AFOREMENTIONED VORTEX. TEMPERATURES WILL CLIMB WELL INTO THE 50S ON MONDAY AND TO 60 OR BETTER ON TUESDAY AS THE ARRIVAL OF THIS COLD FRONT IS DELAYED SLIGHTLY AS LOW PRESSURE RIPPLES UP ALONG IT. THIS SOUTHERN STREAM LOW PRESSURE WILL BRING THE BEST CHANCE OF RAINFALL IN THE EXTENDED PORTION OF THE FORECAST AS STRONG FORCING SHIFTS THROUGH THE AREA WITH THIS PASSAGE OF THIS SYSTEM TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING...WITH ONLY MINOR LAKE EFFECT ACTIVITY EXPECTED LATER WEDNESDAY INTO THURSDAY SOUTHEAST OF LAKE HURON. TEMPERATURES WILL COOL BACK INTO THE MID 50S ON WEDNESDAY...BUT WITH NORTHERN STREAM SHORTWAVE TAKING A WESTERLY TRACK NORTH OF THE GREAT LAKES...THE COLDEST AIR WITH THIS SYSTEM WILL REMAIN OVER CANADA AND EXPECT TEMPERATURES TO REBOUND TO THE UPPER 50S TO AROUND 60 BY THURSDAY. && .MARINE... A FRESH WEST-SOUTHWEST BREEZE WILL GUST INTO THE 25 TO 30 KNOT RANGE TODAY AS A COOL AND UNSTABLE AIRMASS OVERSPREADS AREA WATERS. A FEW GUSTS TO LOW END GALE FORCE WILL BE POSSIBLE FROM OUTER SAGINAW BAY INTO CENTRAL LAKE HURON THIS AFTERNOON...BUT NO ORGANIZED OR WIDESPREAD GALES ARE EXPECTED. WINDS WILL GRADUALLY EASE BY LATE FRIDAY NIGHT BUT WAVES WILL REMAIN REMAIN ELEVATED INTO SATURDAY MORNING. ALL SMALL CRAFT ADVISORIES THEREFORE REMAIN IN EFFECT FOR SAGINAW BAY AND THE NEARSHORE FROM PORT AUSTIN TO HARBOR BEACH UNTIL SATURDAY MORNING. A RENEWED SURGE OF GUSTY WINDS WILL DEVELOP AHEAD OF ANOTHER PUSH OF COLD AIR ON SATURDAY. A BRIEF REPRIEVE CAN BE EXPECTED ON SUNDAY AS SURFACE HIGH PRESSURE SLIDES ACROSS THE AREA...BUT UNSETTLED CONDITIONS WILL QUICKLY REDEVELOP AS THE SURFACE PRESSURE GRADIENT STRENGTHENS EARLY NEXT WEEK. SOUTH WINDS WILL INCREASE TO 20 TO 25 KNOTS BY LATE MONDAY. && .AVIATION...ISSUED 1235 AM EDT FRI OCT 5 2012 //DISCUSSION... COLD FRONTAL BOUNDARY RAPIDLY SHIFTING THROUGH THE AREA EARLY THIS MORNING. SOME EVIDENCE OF LOWER MVFR CIGS IN LIGHT RAIN SHOWERS NOW EMERGING ALONG THE FRONTAL SLOPE...BUT COVERAGE REMAINS TOO SPOTTY TO DEFINE A SPECIFIC MENTION OF MVFR RESTRICTIONS LOCALLY AT THIS POINT. BRIEF INCREASE IN WESTERLY WINDS IMMEDIATELY BEHIND THE FRONT BEFORE EASING BACK INTO THE 10-12KT RANGE. INCREASING MID LEVEL FORCING NORTH OF THIS FRONT WILL BRING A RENEWED CHANCE FOR SHOWERS IN A LOWER CEILING ACROSS MAINLY THE DETROIT AREA BY FRIDAY AFTERNOON. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILING INTERMITTENTLY FALLING 5000 FEET EARLY THIS MORNING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...FROM 8 AM FRIDAY TO 8 AM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...JVC LONG TERM....DG MARINE.......JVC AVIATION.....JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
141 AM EDT FRI OCT 5 2012 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 423 PM EDT THU OCT 4 2012 WV LOOP AND RUC ANALYSIS SHOW NEGATIVE TILTED SHORTWAVE TROUGH OVER NORTHERN MINNESOTA THIS AFTN WITH ASSOCIATED SFC LOW IN THE VCNTY OF KINL. COLD FRONT IS IN PROCESS OF MAKING ITS WAY ACROSS UPR MICHIGAN...BUT MUCH COLDER AIR IS LAGGING BEHIND OVER NORTHERN MINNESOTA. HAVE SEEN ISOLD SHRA FORM THIS AFTN WITH EVEN TSRA. MAIN AREA WAS ON KEWEENAW BUT JUST WITHIN LAST 1 HR ANOTHER LINE OF SHRA HAS FORMED OVER EASTERN LK SUPERIOR/FAR NORTHEAST CWA. DEEP DRYING WRAPPING IN ON SOUTHERN EDGE OF SHORTWAVE TROUGH IS STEEPENING MID LEVEL LAPSE RATES. MOST OF SHRA/TSRA KICKED ON WITHIN THE BETTER LR/S AND ALSO ON LEADING EDGE OF H85 FRONTOGENESIS. OTHERWISE ONCE PESKY FOG HELPED OUT BY MOISTURE OFF LK MICHIGAN BURNED OFF...IT HAS BECOME NICE DAY WITH HIGHS TOPPING OUT IN THE 60S AND EVEN SOME LOWER 70S. THAT WILL BE LAST 70 DEGREES FOR POSSIBLY THIS FALL THOUGH AS BIG CHANGES ARE COMING IN ONCE THE LOW OVER MINNESOTA MOVES TO NORTHERN LK SUPERIOR AND COLDER AIR PLOWS INTO THE REGION. THROUGH FRIDAY...DO NOT EXPECT ANY BIG SNOW ACCUMS. WIDESPREAD SNOW ON CYCLONIC SIDE OF SHORTWAVE TROUGH AND IN MOIST/CYCLONIC FLOW BEHIND SFC LOW NEVER REALLY MAKES IT INTO CWA...INSTEAD LIFTING MORE NORTHEAST INTO ONTARIO. INSTEAD...NORTHWEST CWA GRADUALLY GETS INTO A REGIME WITH PLENTIFUL LOW-LEVEL MOISTURE BLO 10KFT AND WSW BLYR WINDS TURNING MORE WESTERLY WITH TIME. SOUNDINGS INDICATE TEMPS IN MOIST LAYER ARE WARMER THAN -8C UNTIL THE DAYTIME ON FRIDAY. UPSHOT IS THAT INITIAL PRECIP TONIGHT INTO FRIDAY MORNING FOR NW CWA WILL BE MAINLY LIGHT RAIN WITH PERHAPS REALLY SMALL SNOW FLAKES MIXING IN AT TIMES LATER TONIGHT. AFTER EARLY EVENING POPS EAST...RESTRICTED POPS FOR LAKE EFFECT/CYCLONIC FLOW MOISTURE TO KEWEENAW OVERNIGHT TONIGHT AS REST OF AREA STAYS IN UNFAVORABLE WSW WINDS IN LOW-LEVELS. WINDS IN BLYR LATE TONIGHT PUSH TOWARD 30 MPH SO EXPECT WINDS NW CWA TO INCREASE LATE. SHOULD BE FAIRLY QUIET OVER REST OF CWA. SKIES MAY EVEN CLEAR OUT SOME IN THE CNTRL AND EAST OVERNIGHT FOR A TIME. A RATHER MISERABLE DAY IS IN STORE FOR KEWEENAW ON FRIDAY. SOUNDINGS SHOW INCREASING DEPTH TO MOISTURE WITH MOISTURE PUSHING COLDER THAN -10C BY AFTN SO SHOULD SEE MORE AND MORE SNOW MIX WITH RAIN THROUGH THE DAY. BLYR TEMPS REMAIN WARM IN THE UPR 30S AND LOWER 40S...SO EVEN IF PRECIP CHANGES TO MOSTLY SNOW DURING THE DAY /WOULD OCCUR BASED ON WBZERO HEIGHTS FALLING WELL BLO 1000 FT AGL/ LITTLE OR NO SNOW ACCUM SHOULD OCCUR DURING THE DAY. BEST CHANCE FOR SEEING SNOW AS ONLY PTYPE WILL BE ON THE HIGHEST TERRAIN OF THE NW CWA. SIMILAR TO TONIGHT...SHOULD BE PRETTY QUIET MOST OTHER AREAS ON FRIDAY MORNING THOUGH A BIT BREEZY. BY FAR...STRONGEST WINDS WILL BE FOUND ON THE KEWEENAW WITH FAVORED WESTERLY WINDS. MIXED LAYER WINDS EASILY TOP OUT OVER 35 KTS AND TOP OF MIXED LAYER WINDS FROM SOUNDINGS SUPPORT GUSTS PUSHING WELL OVER 40 KTS. WINDS ARE ALSO STRONG ALONG LAKE SUPERIOR FROM IWD TO ONTONAGON. FAVORED WEST WIND DIRECTION AND SUCH STRONG WINDS IN MIXED LAYER IN FACE OF STRONG COLD AIR ADVECTION SUPPORTS FREQUENT GUSTS ON FRIDAY OVER HIGHER TERRAIN OF KEWEENAW PENINSULA REACHING WIND ADVY LEVEL /39 KT OR 45 MPH/. WIND ADVY WAS ISSUED FOR KEWEENAW. FOR THOSE OTHER AREAS NEAR LK SUPERIOR ADVY LEVEL WIND GUSTS SHOULD BE NOT AS FREQUENT...SO DID NOT INCLUDE THOSE AREAS IN ADVY AT THIS TIME. BY MID-LATE AFTN ON FRIDAY...925MB-850MB WINDS VEER MORE WNW WHICH SHOULD BRING MORE OF CWA INTO CYCLONIC LOW-LEVEL MOIST FLOW. EXPECT WX REGIME OVER KEWEENAW TO BEGIN TO SHIFT TOWARD HIGHER TERRAIN OF ALL WESTERN AND POSSIBLE NCNTRL CWA BY 21Z. TEMPS MAY ALSO TRY TO FALL OFF FOR THESE AREAS AS WELL. AGAIN...LIKE THE KEWEENAW EVEN WITH MAINLY SNOW VERSUS RAIN...WARMER BLYR TEMPS AND MINIMAL STRONGER LAKE EFFECT CONVECTION SHOULD PROHIBIT MUCH IN WAY OF SNOW ACCUM. BETTER CHANCE FOR SNOW ACCUMS FOR THE CWA WILL OCCUR MORE ON FRIDAY NIGHT WHICH IS NOW ADDRESSED IN THE LONGER TERM DISCUSSION. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 423 PM EDT THU OCT 4 2012 NAM SHOWS A BROAD 500 MB TROUGH ACROSS THE CENTRAL U.S. WITH A RIDGE OFF THE PACIFIC NW AND A CLOSED LOW OFF THE CA COAST IN A REX BLOCK PATTERN WITH A RIDGE OFF THE EAST COAST 00Z SAT. PATTERN DOES NOT CHANGE MUCH WITH A SHORTWAVE OVER THE NORTHERN PLAINS ROTATING AROUND THE TROUGH AND INTO THE LOWER GREAT LAKES ON SUNDAY. BASICALLY...WILL NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. SINCE THIS IS AN EARLY SEASON SNOW...LOT OF THE TOOLS WILL NOT WORK USING THICKNESSES FOR DETERMINING SNOW AND PRETTY MUCH KEPT WHAT WAS ALREADY IN THERE WHICH IS SNOW IN THE HIGHER TERRAIN AND RAIN IN THE LOWER TERRAIN AND EASTERN CWA. DID LOWER SNOW RATIOS THOUGH AS FEELING IS THAT THE SNOW FLAKE SIZE WILL BE SMALL AND LOWER THAN A 10 TO 1 RATIO WILL WORK. THIS STILL GIVES ME 1-3 INCHES IN THE HIGHER TERRAIN FOR FRI NIGHT THROUGH SAT EVENING. IT WILL BE COLD ENOUGH FOR LAKE EFFECT PCPN AND LOWERED THE LAKE TEMPERATURES TO 10C TO 12C FOR FRI NIGHT AND SAT AS THINKING IS THE LAKE WILL START TO GET TURNED OVER AND WATER TEMPERATURES WILL COOL OFF FROM 12C TO 15C THAT IT IS NOW. 850 MB TEMPERATURES COOL TO AROUND -6C BY 12Z SAT AND THAT IS ENOUGH LAKE EFFECT DELTA-T FOR LAKE EFFECT. BY SUNDAY...WINDS SWITCH TO THE SW AND WITH WARM AIR ADVECTION COMING IN...THIS WILL PUSH THE LAKE EFFECT PCPN OFFSHORE OF THE U.P. IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH ACROSS THE CENTRAL AND EASTERN U.S. WITH A RIDGE OFF THE PACIFIC NW AND A CLOSED LOW OFF THE CA COAST IN A REX BLOCK PATTERN 12Z MONDAY. THERE IS A SHORTWAVE ACROSS SOUTH CENTRAL CANADA THAT IS POISED TO DROP INTO THE UPPER GREAT LAKES WITH AN ALBERTA CLIPPER SYSTEM THAT MOVES THROUGH MON NIGHT INTO TUE. THE TROUGH OVER THE CENTRAL AND EASTERN U.S. STAYS ANCHORED OVER THE UPPER GREAT LAKES INTO WED. ANOTHER CLIPPER TYPE SYSTEM LOOKS TO AFFECT THE AREA ON THU. IT LOOKS TO STAY COLDER THAN NORMAL THROUGH THE EXTENDED PERIOD WITH ACTIVE WEATHER. KEPT MIXTURE OF RAIN AND SNOW IN FOR LATE TUE NIGHT INTO WED MORNING WITH NEXT COLD AIR WAVE THAT COMES THROUGH. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 139 AM EDT FRI OCT 5 2012 UPPER MI WILL BE UNDER THE CIRCULATION OF A LOW PRES SYSTEM MOVING ACROSS NRN ONTARIO TODAY. INITIALLY...CONDITIONS WILL BE VFR AT KIWD/KCMX/KSAW...BUT AS COLDER AIR INCREASES OVERLAKE INSTABILITY AND MOISTURE WRAPS AROUND THE LOW INTO THE AREA...EXPECT CIGS TO BE MVFR AT KCMX BY FCST ISSUANCE TIME AND AT KIWD BEFORE DAYBREAK. THE COLDER AIR WILL ALSO LEAD TO LAKE ENHANCED RAIN/SNOW/IFR CONDITIONS DEVELOPING AT KCMX EARLY THIS MORNING AND THEN CONTINUING THRU THE DAY. WINDS SHOULD VEER ENOUGH TO BRING LAKE EFFECT PCPN INTO KIWD THIS AFTN. SFC TROF DROPPING ACROSS THE LAKE LATER THIS AFTN/EVENING SHOULD BRING HEAVIER -SHSN/IFR CONDITIONS TO KIWD THIS EVENING. MEANWHILE...AFTER TROF PASSES...CONDITIONS SHOULD IMPROVE TO MVFR AT KCMX. AT KSAW...W DOWNSLOPING WINDS THRU THE PERIOD SHOULD RESULT IN VFR CONDITIONS PREVAILING WITH NO PCPN. SFC TROF/-SHSN SHOULD REACH KSAW AROUND THE END OF THIS FCST PERIOD. WITH A TIGHT PRES GRADIENT...WINDS WILL BE STRONG WITH GUSTS AOA 30KT THRU TODAY. STRONGEST WINDS...GUSTING TO 40KT OR SO...WILL BE AT KCMX. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 423 PM EDT THU OCT 4 2012 AN INTENSIFYING LOW PRESSURE SYSTEM WILL MOVE NORTH-NORTHEAST FROM CENTRAL MINNESOTA TO THE U.S./CANADIAN BORDER BY THIS AFTERNOON...BEFORE BEING LOCATED JUST NORTH NORTHWEST OF LAKE SUPERIOR BY LATE TONIGHT. THIS WILL LEAD TO INCREASING SOUTHWESTERLY WINDS ACROSS THE LAKE THIS AFTERNOON WITH GALE FORCE GUSTS OF 35-45KTS EXPECTED OVER MAINLY WRN LAKE SUPERIOR THIS AFTERNOON/EVENING...INCREASING TO 45KTS TONIGHT INTO EARLY FRIDAY. THE LOW WILL SHIFT NORTHEAST ON FRIDAY...BUT WILL KEEP A SFC TROUGH OVER LAKE SUPERIOR THROUGH FRIDAY NIGHT. AS THIS SFC TROUGH SLOWLY SLIDES SE ACROSS LAKE SUPERIOR...EXPECT WINDS TO SHIFT TO THE NORTHWEST AND GUSTS UP TO 35KTS AT TIMES. A HIGH PRESSURE RIDGE WILL BUILD OVER THE UPPER GREAT LAKES REGION ON SATURDAY AND SUNDAY...LOWERING WINDS BELOW 25KTS. WINDS COME UP TO 30 KNOTS FOR MON NIGHT AND TUE WITH NEXT CLIPPER TYPE SYSTEM BRINGING IN SOME COLDER AIR. GETS REAL CLOSE TO A GALE THEN WITH A TIGHTER PRESSURE GRADIENT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MIZ001-003. LAKE SUPERIOR... GALE WARNING FROM 6 AM THIS MORNING TO 10 AM EDT SATURDAY FOR LSZ267. GALE WARNING UNTIL 10 AM EDT SATURDAY FOR LSZ264>266. GALE WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR LSZ162- 240>247. GALE WARNING UNTIL 6 AM EDT SATURDAY FOR LSZ263. GALE WARNING FROM 6 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR LSZ248. LAKE MICHIGAN... GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LMZ221-248-250. && $$ SHORT TERM...JLA LONG TERM...07 AVIATION...ROLFSON MARINE...07
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1200 AM EDT FRI OCT 5 2012 .SYNOPSIS... ISSUED AT 354 PM EDT THU OCT 4 2012 A STRONG COLD FRONT WILL CROSS THE AREA THIS EVENING WITH SHOWERS AND SCATTERED THUNDERSTORMS. SKIES WILL CLEAR LATE TONIGHT AND IT WILL TURN COLDER. EXPECT MOSTLY SUNNY SKIES FRIDAY WITH HIGHS ONLY IN THE 50S. LAKE EFFECT RAIN SHOWERS ARE EXPECTED SATURDAY INTO SUNDAY WITH HIGHS MOSTLY IN THE 4OS. && .UPDATE... ISSUED AT 805 PM EDT THU OCT 4 2012 WE HAVE ISSUED AN UPDATE THIS EVENING TO FRESHEN UP THE FCST BASED ON CURRENT TRENDS. THE TREND IS FOR THE RAIN TO MOVE THROUGH A LITTLE QUICKER THAN PREVIOUSLY EXPECTED...ESPECIALLY UP NORTH WHERE THE RAIN IS LIKELY DONE FOR THIS PORTION OF THE EVENT. RAIN IS STILL MOVING INTO THE SRN PORTIONS OF THE AREA AS THE FRONT PRESSES EAST. THERE HAS BEEN A COUPLE OF LIGHTNING STRIKES OBSERVED...SO WE WILL CONTINUE THE ISOLATED MENTION OF THUNDER. THE SRN PORTION OF THE CWFA WILL SEE RAIN HOLD OVER A LITTLE LONGER AS ANOTHER WAVE OF RAINFALL COMING IN FROM THE SW WILL TAKE A FEW HOURS TO PASS BY THE AREA. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 354 PM EDT THU OCT 4 2012 THE MAIN ISSUE IS THE CONVECTIVE LINE OVER WISCONSIN HEADING TOWARD SOUTHWEST LOWER MICHIGAN AS I WRITE THIS. BEYOND THAT THERE IS THE ISSUE OF LAKE EFFECT RAIN SHOWERS OVER THE WEEKEND. THE COMBINATION OF JET ASSISTED LIFT AND A DEVELOPING LOW LEVEL JET WILL AID THE DEVELOPMENT OF A LINE OF SHOWERS THAT AT 3 PM WAS OVER EASTERN WISCONSIN. AS THIS LINE CROSSES LAKE MICHIGAN I EXPECT THUNDERSTORMS TO DEVELOP WITHIN THAT LINE. AIDING THAT IS A SURGE OF HIGHER SURFACE DEW POINTS JUST AHEAD OF THE COLD FRONT. THE 1000 TO 850 MB MOISTURE TRANSPORT VECTORS INCREASE SIGNIFICANTLY AS THE FRONT CROSSES LAKE MICHIGAN. THE HRRR RUC IS DOING REASONABLY WELL WITH THE CONVECTION ON THE COLD FRONT SO FAR THIS AFTERNOON. SO...BASED ON OUR TIMING TOOL...THE TIMING IN THE HRRR RUC AND RELATED TOOLS I EXPECT A NEARLY SOLID LINE OF SHOWERS AND ISOLATED STORMS TO CROSS THE CWA BETWEEN 6 PM AND 11 PM THIS EVENING. I DO NOT EXPECT SEVERE STORMS AS THE CAPES ARE NOT IMPRESSIVE BUT THERE IS 30 - 40 KNOTS OF DEEP LAYER SHEAR TO WORK WITH. THERE IS ALSO 40 TO 50 KNOTS AS CLOSE TO THE GROUND AS 5000 FT AGL AS THIS LINE MOVES CROSS THE CWA. SO EXPECT GUSTY WINDS WITH THE SHOWERS. ONCE THIS FEATURE MOVES EAST THE STRONG COLD ADVECTION BEHIND THE FRONT WILL RESULT IN CONSIDERABLE SUBSIDENCE SO EXPECT CLEARING SKIES LATER TONIGHT. ANOTHER JET SEGMENT ROTATING THROUGH THE UPPER TROUGH WILL INDUCE A WAVE ON THE FRONT FRIDAY INTO SATURDAY. AT THIS POINT IT SEEMS THE RAIN FROM THAT WILL MOSTLY STAY SOUTH OF THE CWA. IT COULD IMPACT AREAS SOUTH OF I-69 FRIDAY INTO FRIDAY EVENING EVEN SO. I HAVE LOW CHANCE POPS FOR THAT. THE SHORTWAVE TROUGH WITH THE DEEP COLD AIR ROTATES THROUGH THE CWA SATURDAY. THAT WILL RESULT IN LAKE EFFECT RAIN SHOWERS. THANKS TO A NORTH NORTHWEST WIND IN THE BOUNDARY LAYER I EXPECT MOST OF THE SIGNIFICANT SHOWERS TO BE CLOSE TO LAKE SHORE. EVEN SO THE AIR IS UNSTABLE ENOUGH THAT ALL AREAS SHOULD SEE SOME SHOWERS IN THE AFTERNOON. SATURDAY NIGHT THOSE SHOWERS WILL CONTINUE NEAR THE LAKE SHORE BUT SOME CLEARING IS POSSIBLE INLAND. COLD BE A FREEZE EARLY SUNDAY MORNING NORTH AND EAST OF GRR. WE WILL HAVE TO WATCH THAT FOR A POSSIBLE FREEZE WARNING. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 354 PM EDT THU OCT 4 2012 STILL EXPECTING SOME WEAK LAKE EFFECT RAIN SHOWERS INTO SUNDAY... HOWEVER SURFACE RIDGING SHOULD BE BREAKING MUCH OF IT UP THROUGH THE DAY. FROST POTENTIAL LOOKS RATHER GOOD INTO SUNDAY NIGHT AS SKIES CLEAR. WE WILL HAVE TO SEE HOW MUCH MIXING REMAINS OVER THE REGION...WHICH COULD LESSEN THE IMPACTS. THE NEXT RAIN MAKER WILL COME IN THE FORM OF ANOTHER COLD FRONT EXPECTED LATE TUESDAY INTO WEDNESDAY. COULD BE POCKETS OF STEADIER RAINS AS THIS FRONT LOOKS MUCH LIKE THIS EVENING/S FRONT. HAVE LEFT THUNDER OUT HOWEVER AS THE TIMING OF THE FROPA SHOULD BE LATE TUESDAY NIGHT. THE CHILLY AIR WILL SLOWLY LOSE IT/S GRIP ON THE REGION INTO EARLY NEXT WEEK. H8 TEMPS BELOW 0C MOVE EAST OF THE AREA BY MONDAY AFTERNOON SO A SLIGHTLY WARMING TREND IS EXPECTED WITH UPPER 50S AND LOWER 60S FOR MONDAY AND TUESDAY. ANOTHER SHOT OF COOLER AIR IS EXPECTED BEHIND THE TUESDAY NIGHT FRONT...HOWEVER THIS LOOKS TO BE A QUICKER SHOT...WITH H8 TEMPS ALREADY WARMING BY THURSDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1200 PM EDT FRI OCT 5 2012 EXPECT MOSTLY VFR TONIGHT ALTHOUGH SOME SHOWERS WILL BRING PATCHY MVFR THROUGH 09Z ESPECIALLY AT AZO AND BTL. SOUTHWEST WINDS WILL GUST TO NEAR 20 KNOTS AT TIMES BEFORE DECREASING LATE TONIGHT. && .MARINE... ISSUED AT 354 PM EDT THU OCT 4 2012 I EXTENDED THE SMALL CRAFT ADVISORY INTO SATURDAY NIGHT SINCE WAVE HEIGHTS ARE NOT EXPECTED TO SUBSIDE BELOW 4 FEET UNTIL EARLY SUNDAY MORNING. THE EXPERIMENTAL GREAT LAKES WATER SPOUT FORECAST SHOWS THE BEST SHOT OF WATER SPOUTS AS BEING SATURDAY AS THE DEEPER COLD AIR MOVES IN. I PUT WATER SPOUTS IN THE NEAR SHORE DURING THAT TIME. THE HRRR SUGGEST POSSIBLE NEAR GALE WINDS WITH THE FRONT THIS EVENING THAT WILL HAVE TO BE WATCHED TOO. && .HYDROLOGY... ISSUED AT 354 PM EDT THU OCT 4 2012 RAINFALL WILL BE LIMITED AT BEST OVER THE NEXT WEEK SO EVEN WITH THE RAINS LAST NIGHT I DO NOT SEE ANY SIGNIFICANT FLOODING ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SUNDAY FOR LMZ844>849. && $$ UPDATE...NJJ SYNOPSIS...WDM SHORT TERM...WDM LONG TERM...JK AVIATION...OSTUNO HYDROLOGY...WDM MARINE...WDM
AREA FORECAST DISCUSSION
NWS BILLINGS MT
312 PM MDT FRI OCT 5 2012 .SHORT TERM...VALID FOR SAT AND SUN... THE MID-LEVEL SHORT WAVE TROUGH APPROACHING FROM THE NORTH AS OF 20 UTC TODAY WILL BE THE LAST IN THE RECENT SERIES OF WAVES THAT HAVE AFFECTED US IN NORTH-NORTHWEST FLOW ALOFT. HOWEVER...BEFORE WE BEGIN A SLOW WARMING TREND AS THE MEAN 500-HPA TROUGH THAT IS BEING FED BY THESE WAVES HEADS EAST ON SAT...WE WILL DEAL WITH A UPSLOPE-ASSISTED SNOW EVENT IN PARTS OF THE AREA TONIGHT. TONIGHT...THE 12 UTC GFS AND NAM AND SEVERAL RECENT HRRR AND RAP SOLUTIONS ALL INCREASED QPF AMOUNTS FROM FAR SOUTH CENTRAL MT TO SHERIDAN COUNTY WY. THIS IS BASED ON 1/ UPSLOPE FLOW WHICH LASTS LONGER THAN EARLIER EXPECTED WITH A BIT SLOWER WAVE TIMING...AND 2/ A MODEST BUT DEFINED AREA OF MID-LEVEL FRONTOGENESIS NEAR THE 700 HPA LAYER THAT ASSISTS IN DEEPER VERTICAL MOTION ACROSS PART OF NORTH CENTRAL WY. SUBSTANTIAL 500-300 Q-VECTOR CONVERGENCE... AND STEEP MID-LEVEL LAPSE RATES...IS YIELDING CONVECTIVE SHOWERS OVER MUCH OF THE AREA ALREADY...AND THOSE ELEMENTS WILL HELP OUT THE POTENTIAL FOR SNOW CENTERED OVER SHERIDAN COUNTY AS WELL. IT LOOKS LIKE THE DENDRITIC LAYER WILL ALSO BE SATURATED AND HAVE A DECENT AREA OF OMEGA IN IT OVER NORTH CENTRAL WY...WHICH FURTHER SOLIDIFIED OUR DECISION TO ISSUE A WINTER WEATHER ADVISORY UNTIL 12 UTC SAT FOR THE SHERIDAN FOOTHILLS. INTERESTINGLY...THERE WAS A STRONG SIGNAL FOR ACCUMULATING SNOW IN THE CITY OF SHERIDAN IN THE 12 UTC MET MOS. WHILE WE FEEL SHERIDAN ITSELF WILL LIKELY BE IN LINE FOR ONLY AN INCH OR TWO OF SNOW...IT IS A BIT RARE FOR A 4 INCH SNOW FORECAST TO SHOW UP IN THE MOS FOR SHERIDAN...SO THE SITUATION DOES WARRANT CLOSE MONITORING. AT THE VERY LEAST...THE STORY AREA AND OTHER FOOTHILLS LOCATIONS LOOK IN LINE TO GET 2-4 INCHES OF SNOW...ESPECIALLY IF FORCING ALOFT LINGERS PAST 06 UTC LIKE THE 12 UTC NAM SUGGESTS. WE ALSO HAVE LIKELY POPS FOR AREAS LIKE FISHTAIL AND RED LODGE THIS EVENING...BUT IT SEEMS LIKE THE QPF AND RESULTANT SNOW IN THOSE AREAS WILL BE LESS SINCE FORCING ALOFT WILL BE LESS ROBUST THERE. FINALLY...WE STILL EXPECT A WIDESPREAD HARD FREEZE TONIGHT...BUT WE ARE ALSO STILL GOING A BIT WARMER THAN PURE MOS-BASED NUMBERS WITH OUR FORECAST LOWS. THAT/S OUT OF RESPECT TO POTENTIAL FOR A SLOW DECREASE IN CLOUDS...MAINLY IN SOUTH CENTRAL MT. THE CLOUDS HAVE CAUSED A COLD BIAS ON THE ORDER OF 10+ F TO MOS DURING THE LAST TWO DAYS...SO WE ARE A BIT HESITANT TO RUN WITH IT...THOUGH SURFACE DEWPOINTS HAVE FINALLY FALLEN ENOUGH FOR LOWS BELOW 30 F IN MOST AREAS TONIGHT. SAT...MODEST MID-LEVEL WARM AIR ADVECTION WILL BEGIN...AND SO WE WILL BEGIN A WARMING TREND. THE 12 UTC MOS GUIDANCE ALL RESPONDS TO THIS WARMING ALOFT BY SHOWING HIGHS WELL INTO THE 40S F. WARM AIR ADVECTION ALOFT AND RELATIVELY WEAK /ALBEIT DOWNSLOPE/ WINDS IN THE LOW LEVELS ARE NOT VERY FAVORABLE FOR WARMING THOUGH...SO WE WERE CAUTIOUS IN GOING TOO MUCH WARMER THAN MOS AT THIS TIME. SUN...MORE AGGRESSIVE WARMING ALOFT IS EXPECTED AS A SURFACE LOW HEADS EAST ACROSS SOUTHERN CANADA DURING THE DAY. THE 12 UTC GFS IS A BIT WARMER THAN THE REST OF THE GUIDANCE ALOFT WITH 850-HPA TEMPERATURES UP TO +13 C AT BILLINGS BY AFTERNOON...BUT WITH THE DOWNSLOPE FLOW IN THE BOUNDARY LAYER AND A BIT OF BACKING TO THE FLOW ALOFT...THE WARMER SOLUTION IS PROBABLY A GOOD ONE. WE FEEL THAT MIXING WILL BE MORE EFFICIENT AS WELL WITH MORE FLOW IN THE SURFACE TO 2 KM AGL LAYER...SO WE BASED HIGHS MORE OFF OF MIXING DEPTHS THAN MOS...WHICH MEANT RAISING THEM JUST A BIT. SCHULTZ .LONG TERM...VALID FOR MON...TUE...WED...THU...FRI... EXTENDED MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE MIDDLE OF NEXT WEEK THEN DIVERGE QUITE A BIT BY LATE WEDNESDAY. OVERALL A STRAIGHT NORTH TO NORTHWEST FLOW ALOFT WILL BE OVER THE FORECAST AREA MONDAY AND TUESDAY. A WEAK FRONT IS PROGGED TO MOVE SOUTH ACROSS THE AREA LATE IN THE DAY MONDAY INTO MONDAY NIGHT WHICH WILL BRING A SLIGHT CHANCE FOR A RAIN OR SNOW SHOWER. HOWEVER...NOT MUCH IN THE WAY OF MOISTURE WITH THIS DISTURBANCE SO ANY SHOWER ACTIVITY IS EXPECTED TO BE LIGHT. BELOW NORMAL TEMPERATURES CAN BE EXPECTED MONDAY INTO TUESDAY WITH HIGHS MAINLY IN THE 50S. MODELS BEGIN TO DIVERGE LATE WEDNESDAY AS THE ECMWF STARTS TO TURN THE NORTHWEST FLOW MORE ZONAL THEN BEGIN TO BUILD A RIDGE THURSDAY INTO FRIDAY. HOWEVER...THE 12Z GFS NOW BRINGS ANOTHER COLD FRONT SOUTH LATE WEDNESDAY NIGHT INTO THURSDAY...WHEREAS...THE PREVIOUS RUN BEGAN TO BUILD A RIDGE. WILL NOT MAKE ANY SIGNIFICANT CHANGES WITH THIS PACKAGE AND SEE WHAT THE NEXT MODEL RUN LOOKS LIKE. AS THINGS STAND NOW...DRY CONDITIONS CAN BE EXPECTED WEDNESDAY THROUGH FRIDAY WITH TEMPERATURES WARMING BACK TO AROUND SEASONAL LEVELS. HOOLEY && .AVIATION... SCATTERED SNOW SHOWERS WILL BE POSSIBLE ACROSS THE ENTIRE FORECAST AREA THROUGH MIDNIGHT RESULTING IN OCCASIONALL MVFR TO IFR CONDITIONS. IN ADDITION...AREAS OF FOG WILL BE POSSIBLE ACROSS THE PLAINS MAINLY WEST OF KMLS. OTHERWISE...VFR CONDITIONS WILL PREVAIL ACROSS THE PLAINS. HOWEVER...MORE NUMEROUS AND HEAVIER SNOW SHOWER ACTIVITY IS EXPECTED ACROSS THE BIG HORN AND PRYOR MOUNTAINS...AS WELL AS THE FOOTHILLS AND LOWER ELEVATIONS OF SHERIDAN COUNTY. MVFR TO IFR CONDITIONS ARE EXPECTED THROUGHOUT THE NIGHT FOR THE EASTERN FOOTHILLS OF THE BIG HORN MOUNTAINS EASTWARD ACROSS SHERIDAN COUNTY. ALL MOUNTAIN LOCATIONS WILL BE OBSCURED THROUGHOUT THE NIGHT. HOOLEY && .PRELIMINARY POINT TEMP/POPS... SAT SUN MON TUE WED THU FRI ----------------------------------------------------------- BIL 024/045 033/063 038/056 037/054 036/061 038/056 039/062 41/U 00/U 01/B 22/W 00/U 00/U 11/U LVM 019/045 022/059 030/057 026/053 030/062 032/059 033/058 31/U 10/U 01/B 22/W 01/B 11/U 11/U HDN 026/052 028/063 038/059 037/054 036/063 035/061 036/064 41/U 10/U 01/B 22/W 00/U 00/U 01/U MLS 022/049 030/062 041/056 036/053 035/061 037/054 037/061 21/U 10/B 12/W 21/B 00/U 00/U 01/U 4BQ 022/046 027/059 039/058 038/053 035/061 038/059 038/061 20/U 00/B 01/B 32/W 00/U 00/U 01/U BHK 020/046 028/057 040/054 033/050 033/060 034/053 033/059 10/U 00/B 12/W 21/B 00/U 00/U 01/U SHR 025/040 024/056 034/056 032/050 032/061 033/060 036/057 91/U 10/U 01/B 22/W 10/U 11/U 01/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MDT SATURDAY FOR ZONE 99. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
123 PM MDT FRI OCT 5 2012 .SHORT TERM...VALID FOR TDY AND SAT... WE HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FROM 00 UTC TO 12 UTC FOR THE SHERIDAN FOOTHILLS FORECAST ZONE FOR 2 TO 4 INCHES OF SNOW ACCUMULATION. THERE IS ENOUGH EVIDENCE IN THE 12 UTC RUNS OF THE NAM AND GFS AND VARIOUS OTHER RECENT GUIDANCE TO HOIST THE HEADLINE. MORE DETAILS ON THIS WILL FOLLOW WITH THE FULL FORECAST DISCUSSION BY ABOUT 21 UTC. SCHULTZ PREVIOUS DISCUSSION...ISSUED AT 1055 AM MDT FRI OCT 5 2012... THE FORECAST WAS UPDATED TO INCREASE POPS A BIT TODAY ACROSS MUCH OF THE AREA AS A 500-HPA SHORT WAVE TROUGH DROPS SOUTHWARD ACROSS THE AREA. MID-LEVEL LAPSE RATES WILL STEEPEN THIS AFTERNOON WHILE MID-LEVEL COLD AIR ADVECTION INCREASES WITH THE WAVE...WHICH WILL BE SUFFICIENT FOR SCATTERED SHOWERS. THAT COVERAGE HAS SUPPORT ON THE 12 UTC NAM AND GFS...AS WELL AS THE LAST FEW HRRR RUNS. A MIX OF RAIN AND SNOW WAS MENTIONED EVEN AS SURFACE TEMPERATURES REACH THE 40 F OR BETTER MARK IN PLACES SINCE THE WET BULB PROFILE WILL STILL SUPPORT SNOW. THE TYPE OF SNOW SHOWERS EXPECTED TODAY OFTEN YIELD TEMPORARY BUT SIGNIFICANT REDUCTIONS IN VISIBILITY. NOTE WE ALSO EXTENDED AT LEAST SOME 20 TO 30 POPS INTO THIS EVENING BASED ON THE LATEST TRENDS IN THE 12 UTC NAM AND GFS SOLUTIONS...WHICH BOTH SHOW A BIT SLOWER TIMING TO THE SHORT WAVE ALOFT. IT APPEARS THAT FORCING WITH THE WAVE MAY KEEP SOME SHOWERS AROUND BEYOND 00 UTC. ALONG THE FOOTHILLS LIKE AT FISHTAIL AND RED LODGE SOUTHEAST INTO THE BIG HORN RANGE AND SHERIDAN COUNTY WY...LOW-LEVEL FLOW HAS AN UPSLOPE COMPONENT TO IT...AND THAT WILL CONTINUE THROUGH AT LEAST 06 UTC. ADD IN THE 500-300 HPA Q-VECTOR CONVERGENCE WITH THE WAVE ALOFT AND THE SITUATION EASILY MERITS LIKELY POPS IN THESE PLACES RIGHT INTO THE EVENING. ADVERTISED SNOW ACCUMULATIONS FALL MOSTLY INTO THE 1 TO 3 INCH RANGE. HOWEVER...THERE IS A TREND WITHIN THE 12 UTC GUIDANCE FOR A DEEPER UPSLOPE WIND SIGNATURE WHICH LASTS A COUPLE HOURS LONGER THAN EARLIER ANTICIPATED...SO WE WILL NEED TO KEEP AN EYE ON THE POTENTIAL FOR A BIT MORE SNOW. OUR CONCERN FOR GREATER SNOW ACCUMULATIONS WILL BE MAINLY IN SHERIDAN COUNTY WITH THE 12 UTC NAM ESPECIALLY AGGRESSIVE WITH QPF TOWARD AND PAST THE 00 UTC HOUR ALL THE WAY UP INTO FAR SOUTH CENTRAL MT. MOISTURE IN THE MODEL IS NON-CONVECTIVE...AND THUS APPEARS TIED TO AN AREA OF WEAK MID-LEVEL FRONTOGENESIS. THE 12 UTC GFS NOW HAS KEYS ON THIS AREA OF SLIGHTLY ENHANCED FRONTOGENESIS AS WELL...SO WE CHOSE TO INCREASE POPS TO THE LIKELY THRESHOLD NOT ONLY OVER THE FOOTHILLS OF THE BIG HORNS LIKE AT STORY...BUT EVEN AT SHERIDAN AND UP INTO SOUTHERN BIG HORN COUNTY IN MT FOR THE EVENING HOURS. THIS RAISES OUR CONCERN A BIT AGAIN FOR THE POSSIBILITY OF REQUIRING A WINTER WEATHER ADVISORY CENTERED ON THIS EVENING IN AREAS LIKE STORY. WE WILL CONTINUE TO EVALUATE THAT AS THE DAY WEARS ON. SCHULTZ .LONG TERM...VALID FOR SUN...MON...TUE...WED...THU... NORTHERLY FLOW WILL CONTINUE ACROSS THE REGION THROUGH THE MIDDLE OF NEXT WEEK...WITH RIDGING MAKING A RETURN BY MAYBE NEXT THURSDAY. THIS PATTERN WILL KEEP TEMPERATURES AT OR BELOW AVERAGE AS WELL AS BRING OCCASIONAL DISTURBANCES KEEPING CONDITIONS UNSETTLED. MAINLY DRY CONDITIONS EXPECTED SUNDAY WITH TEMPERATURES IN THE 50S TO NEAR 60 DEGREES AHEAD OF A SYSTEM ARRIVING LATE MONDAY. TEMPERATURES MONDAY SHOULD MAKE IT INTO THE MID 50S BEFORE COOLER AIR AND PRECIPITATION DROP SOUTHWARD INTO THE AREA LATE IN THE DAY. PRECIPITATION CHANCES MONDAY NIGHT AND TUESDAY LOOK PRETTY GOOD WITH STRONG QG FORCING DEVELOPING OVER THE AREA ALONG WITH LOW LEVEL UPSLOPE FLOW. INCREASED POPS TO CHANCE CATEGORY FOR THIS TIME FRAME. SYSTEM EXITS THE AREA EARLY WEDNESDAY WITH DRIER AIR BUILDING IN...BUT STILL ENOUGH MOISTURE FOR A FEW MOUNTAIN SNOW SHOWERS INTO WEDNESDAY NIGHT. UPPER LOW OVER CALIFORNIA EARLY IN THE WEEK BEGINS TO TRANSIT TO THE EAST MID WEEK HELPING TO DRIVE RIDGING NORTHWARD INTO THE AREA BY THURSDAY. THIS MAY PUSH TEMPERATURES INTO THE MID TO UPPER 60S THURSDAY AND FRIDAY...HOWEVER SOME MODELS SUGGESTING A GOOD DEAL OF MOISTURE AND DECENT MID LEVEL FORCING WILL ACCOMPANY THIS SOUTHERLY FLOW ALOFT RESULTING IN BETTER PRECIPITATION CHANCES KEEPING TEMPERATURES DOWN. WILL CONTINUE TO WATCH THIS LATE WEEK SYSTEM FOR POSSIBLE ADJUSTMENTS WITH LATER FORECASTS. CHAMBERS && .AVIATION... LOW LEVEL UPSLOPE WINDS COMBINED WITH RAIN AND SNOW SHOWERS WILL RESULT IN MVFR TO LOCAL IFR CONDITIONS IN THE MOUNTAINS AND ALONG THE FOOTHILLS THROUGHOUT THE DAY. ELSEWHERE...VFR TO LOCAL MVFR CONDITIONS WILL PREVAIL WITH SCATTERED RAIN OR SNOW SHOWERS. THE RAIN AND SNOW SHOWERS WILL DISSIPATE AROUND MID EVENING WITH LOCAL AREAS OF FOG POSSIBLE LATE TONIGHT INTO SATURDAY MORNING. HOOLEY && .PRELIMINARY POINT TEMP/POPS... TDY SAT SUN MON TUE WED THU ------------------------------------------------------- BIL 041 023/045 031/060 038/056 039/049 036/059 040/056 4/W 31/U 00/U 01/B 32/W 00/U 00/U LVM 039 011/045 021/056 030/057 028/049 030/060 034/059 4/W 31/U 11/U 11/B 32/W 00/U 00/U HDN 046 022/052 028/062 038/059 039/053 036/061 037/061 4/W 31/U 10/U 01/B 32/W 00/U 00/U MLS 044 022/049 030/061 041/056 038/049 035/059 039/054 2/W 21/U 11/B 12/W 32/W 00/U 00/U 4BQ 044 021/049 026/059 039/058 040/049 035/059 040/059 3/W 20/U 00/B 01/B 33/W 00/U 00/U BHK 043 020/049 028/057 040/054 035/046 033/058 036/052 2/W 00/U 00/B 12/W 32/W 00/U 00/U SHR 040 020/044 024/056 034/056 034/046 032/059 035/060 6/W 61/U 10/U 00/U 33/W 00/U 00/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO 6 AM MDT SATURDAY FOR ZONE 99. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1055 AM MDT FRI OCT 5 2012 .SHORT TERM...VALID FOR TDY AND SAT... THE FORECAST WAS UPDATED TO INCREASE POPS A BIT TODAY ACROSS MUCH OF THE AREA AS A 500-HPA SHORT WAVE TROUGH DROPS SOUTHWARD ACROSS THE AREA. MID-LEVEL LAPSE RATES WILL STEEPEN THIS AFTERNOON WHILE MID-LEVEL COLD AIR ADVECTION INCREASES WITH THE WAVE...WHICH WILL BE SUFFICIENT FOR SCATTERED SHOWERS. THAT COVERAGE HAS SUPPORT OF THE 12 UTC NAM AND GFS...AS WELL AS THE LAST FEW HRRR RUNS. A MIX OF RAIN AND SNOW WAS MENTIONED EVEN AS SURFACE TEMPERATURES REACH THE 40 F OR BETTER MARK IN PLACES SINCE THE WET BULB PROFILE WILL STILL SUPPORT SNOW. THE TYPE OF SNOW SHOWERS EXPECTED TODAY OFTEN YIELD TEMPORARY BUT SIGNIFICANT REDUCTIONS IN VISIBILITY. NOTE WE ALSO EXTENDED AT LEAST SOME 20 TO 30 POPS INTO THIS EVENING BASED ON THE LATEST TRENDS IN THE 12 UTC NAM AND GFS SOLUTIONS...WHICH BOTH SHOW A BIT SLOWER TIMING TO THE SHORT WAVE ALOFT. IT APPEARS THAT FORCING WITH THE WAVE MAY KEEP SOME SHOWERS AROUND BEYOND 00 UTC. ALONG THE FOOTHILLS LIKE AT FISHTAIL AND RED LODGE SOUTHEAST INTO THE BIG HORN RANGE AND SHERIDAN COUNTY WY...LOW-LEVEL FLOW HAS AN UPSLOPE COMPONENT TO IT...AND THAT WILL CONTINUE THROUGH AT LEAST 06 UTC. ADD IN THE 500-300 HPA Q-VECTOR CONVERGENCE WITH THE WAVE ALOFT AND THE SITUATION EASILY MERITS LIKELY POPS IN THESE PLACES RIGHT INTO THE EVENING. ADVERTISED SNOW ACCUMULATIONS FALL MOSTLY INTO THE 1 TO 3 INCH RANGE. HOWEVER...THERE IS A TREND WITHIN THE 12 UTC GUIDANCE FOR A DEEPER UPSLOPE WIND SIGNATURE WHICH LASTS A COUPLE HOURS LONGER THAN EARLIER ANTICIPATED...SO WE WILL NEED TO KEEP AN EYE ON THE POTENTIAL FOR A BIT MORE SNOW. OUR CONCERN FOR GREATER SNOW ACCUMULATIONS WILL BE MAINLY IN SHERIDAN COUNTY WITH THE 12 UTC NAM ESPECIALLY AGGRESSIVE WITH QPF TOWARD AND PAST THE 00 UTC HOUR ALL THE WAY UP INTO FAR SOUTH CENTRAL MT. MOISTURE IN THE MODEL IS NON-CONVECTIVE...AND THUS APPEARS TIED TO AN AREA OF WEAK MID-LEVEL FRONTOGENESIS. THE 12 UTC GFS NOW HAS EYES ON THIS AREA OF SLIGHTLY ENHANCED FRONTOGENESIS AS WELL...SO WE CHOSE TO INCREASE POPS TO THE LIKELY THRESHOLD NOT ONLY OVER THE FOOTHILLS OF THE BIG HORNS LIKE AT STORY...BUT EVEN AT SHERIDAN AND UP INTO SOUTHERN BIG HORN COUNTY IN MT FOR THE EVENING HOURS. THIS RAISES OUR CONCERN A BIT AGAIN FOR THE POSSIBILITY OF REQUIRING A WINTER WEATHER ADVISORY CENTERED ON THIS EVENING IN AREAS LIKE STORY. WE WILL CONTINUE TO EVALUATE THAT AS THE DAY WEARS ON. SCHULTZ .LONG TERM...VALID FOR SUN...MON...TUE...WED...THU... NORTHERLY FLOW WILL CONTINUE ACROSS THE REGION THROUGH THE MIDDLE OF NEXT WEEK...WITH RIDGING MAKING A RETURN BY MAYBE NEXT THURSDAY. THIS PATTERN WILL KEEP TEMPERATURES AT OR BELOW AVERAGE AS WELL AS BRING OCCASIONAL DISTURBANCES KEEPING CONDITIONS UNSETTLED. MAINLY DRY CONDITIONS EXPECTED SUNDAY WITH TEMPERATURES IN THE 50S TO NEAR 60 DEGREES AHEAD OF A SYSTEM ARRIVING LATE MONDAY. TEMPERATURES MONDAY SHOULD MAKE IT INTO THE MID 50S BEFORE COOLER AIR AND PRECIPITATION DROP SOUTHWARD INTO THE AREA LATE IN THE DAY. PRECIPITATION CHANCES MONDAY NIGHT AND TUESDAY LOOK PRETTY GOOD WITH STRONG QG FORCING DEVELOPING OVER THE AREA ALONG WITH LOW LEVEL UPSLOPE FLOW. INCREASED POPS TO CHANCE CATEGORY FOR THIS TIME FRAME. SYSTEM EXITS THE AREA EARLY WEDNESDAY WITH DRIER AIR BUILDING IN...BUT STILL ENOUGH MOISTURE FOR A FEW MOUNTAIN SNOW SHOWERS INTO WEDNESDAY NIGHT. UPPER LOW OVER CALIFORNIA EARLY IN THE WEEK BEGINS TO TRANSIT TO THE EAST MID WEEK HELPING TO DRIVE RIDGING NORTHWARD INTO THE AREA BY THURSDAY. THIS MAY PUSH TEMPERATURES INTO THE MID TO UPPER 60S THURSDAY AND FRIDAY...HOWEVER SOME MODELS SUGGESTING A GOOD DEAL OF MOISTURE AND DECENT MID LEVEL FORCING WILL ACCOMPANY THIS SOUTHERLY FLOW ALOFT RESULTING IN BETTER PRECIPITATION CHANCES KEEPING TEMPERATURES DOWN. WILL CONTINUE TO WATCH THIS LATE WEEK SYSTEM FOR POSSIBLE ADJUSTMENTS WITH LATER FORECASTS. CHAMBERS && .AVIATION... LOW LEVEL UPSLOPE WINDS COMBINED WITH RAIN AND SNOW SHOWERS WILL RESULT IN MVFR TO LOCAL IFR CONDITIONS IN THE MOUNTAINS AND ALONG THE FOOTHILLS THROUGHOUT THE DAY. ELSEWHERE...VFR TO LOCAL MVFR CONDITIONS WILL PREVAIL WITH SCATTERED RAIN OR SNOW SHOWERS. THE RAIN AND SNOW SHOWERS WILL DISSIPATE AROUND MID EVENING WITH LOCAL AREAS OF FOG POSSIBLE LATE TONIGHT INTO SATURDAY MORNING. HOOLEY && .PRELIMINARY POINT TEMP/POPS... TDY SAT SUN MON TUE WED THU ------------------------------------------------------- BIL 041 023/045 031/060 038/056 039/049 036/059 040/056 4/W 31/U 00/U 01/B 32/W 00/U 00/U LVM 039 011/045 021/056 030/057 028/049 030/060 034/059 4/W 31/U 11/U 11/B 32/W 00/U 00/U HDN 046 022/052 028/062 038/059 039/053 036/061 037/061 4/W 31/U 10/U 01/B 32/W 00/U 00/U MLS 044 022/049 030/061 041/056 038/049 035/059 039/054 3/W 21/U 11/B 12/W 32/W 00/U 00/U 4BQ 044 021/049 026/059 039/058 040/049 035/059 040/059 3/W 20/U 00/B 01/B 33/W 00/U 00/U BHK 043 020/049 028/057 040/054 035/046 033/058 036/052 2/W 00/U 00/B 12/W 32/W 00/U 00/U SHR 040 020/044 024/056 034/056 034/046 032/059 035/060 6/W 61/U 10/U 00/U 33/W 00/U 00/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
317 PM CDT FRI OCT 5 2012 .DISCUSSION... A FRONTOGENETICALLY FORCED SNOW BAND CONTINUES TO DRIFT SLOWLY EAST SOUTHEAST ACROSS THE SANDHILLS THIS AFTERNOON. THIS AREA OF SNOW SHOULD CONTINUE MOVING EAST SOUTHEAST AND WEAKEN AS THE THERMAL FORCING RELAXES. ANOTHER ROUND OF SNOW IS FORECAST TO DEVELOP ACROSS SWRN NEB AND THE PANHANDLE LATE TONIGHT THROUGH EARLY SATURDAY AFTN. THIS IS BASED ON THE CONSENSUS OF THE 12Z GFS...WRF...NAM...GEM AND 00Z ECM. HOWEVER THE LATEST RADAR AND RAP/HRRR SOLNS ARE SUGGESTING A MORE EASTERLY TRACK OF THE DISTURBANCE...CURRENTLY OVER MT...WHICH COULD PRODUCE SNOW ACROSS NCNTL NEB. THE 18Z NAM IS IN EXCELLENT AGREEMENT WITH THE GEMREG KEEPING THE BEST FORCING AND SNOW SOUTHWEST AND ITS NOT UNUSUAL FOR THE RAP AND HRRR TO BE OFF BUT THE RADAR TRENDS ARE OF CONCERN. A QPF BLEND OF THE MODELS ABOVE AND A 10 TO 1 RATIO PRODUCE 1 TO 2 INCHES OF SNOW ACROSS THE FAR WEST AND SOUTHWEST SO NO WINTER WEATHER ADVISORY WILL BE NECESSARY ASSUMING BRIDGES AND ROAD SURFACES DONT CROSS THE FREEZING MARK OVERNIGHT. THE CLOUD COVER BUILDING IN AHEAD OF THIS DISTURBANCE LEAVES A NARROW WINDOW FOR FREEZING TEMPERATURES ACROSS LINCOLN COUNTY. OTHER AREAS WEST REMAIN OVERCAST AND AREAS NORTH AND EAST HAVE ALREADY HAD A FREEZE. SKIES SHOULD CLEAR OUT BY EARLY SATURDAY EVENING WITH WINDS BECOMING LIGHT WEST OVERNIGHT. LOW PRESSURE WILL BEGIN DROPPING SOUTH THROUGH CANADA. A BLEND OF NAM AND MET GUIDANCE WITH NAM12 BIAS CORRECTION PRODUCED LOWS IN THE TEENS IN SOME AREAS SUNDAY MORNING. HIGHS REBOUND INTO THE 50S SUNDAY AFTERNOON AS WEST WINDS CONTINUE. LOWS IN THE 20S FOLLOW MONDAY MORNING WITH HIGHS AROUND 70 MONDAY AFTERNOON. WEST WINDS WILL CONTINUE THROUGH THIS PERIOD AS LOW PRESSURE MOVES SLOWLY EAST THROUGH MANITOBA AND SASKATCHEWAN. TUESDAY THROUGH FRIDAY. UPPER FLOW SHOULD TRANSITION FROM NORTHWEST FLOW ALOFT AT THE START OF THE PERIOD...TO SOUTHWEST FLOW ALOFT TOWARD THE END OF THE WEEK AS A LARGE UPPER LEVEL LOW PRESSURE SYSTEM PUSHES EAST OVER THE DESERT SOUTHWEST. MODELS AGREE SOMEWHAT THAT THIS UPPER LEVEL LOW PRESSURE SYSTEM WILL EVENTUALLY MOVE NORTHEAST TOWARD AND ACROSS OUR AREA NEXT WEEKEND. THIS IS JUST BEYOND THE FORECAST PERIOD...AND ANY PRECIPITATION ASSOCIATED WITH THIS SYSTEM WOULD BE BEYOND FRIDAY...SO DRY WEATHER IS CURRENTLY BEING FORECAST THROUGH FRIDAY. OTHERWISE...HIGH TEMPERATURES WILL STAY MOSTLY IN THE 60S...WITH PERHAPS ONLY 50S BY FRIDAY BEHIND A COLD FRONT. THIS FRONT SHOULD BECOME STATIONARY JUST TO OUR SOUTH LATER FRIDAY AND THEN POTENTIALLY MOVE BACK NORTH THROUGH THE AREA DURING THE WEEKEND AS A WARM FRONT. WILL CONTINUE TO MONITOR THE POTENTIAL SYSTEM FOR NEXT WEEKEND. && .AVIATION... AREAS OF MVFR CEILINGS CONTINUE ACROSS PORTIONS OF SOUTHWEST AND WESTERN NEBRASKA. THESE ARE EXPECTED TO LIFT...AND BY EARLY EVENING MOSTLY JUST A MID LEVEL CLOUD DECK IS EXPECTED. ANOTHER SYSTEM WILL MOVE SOUTHEAST ACROSS THE AREA AFTER 06Z SATURDAY...WITH CEILINGS LOWERING TO MVFR AND POSSIBLE LIGHT SNOW WEST OF A LINE FROM KIML TO KOGA TO KAIA. SFC WINDS WILL BE LIGHT THROUGH THE PERIOD. && .FIRE WEATHER... FIRE DANGER WILL BECOME VERY HIGH SUNDAY AND MONDAY AFTERNOON. MODEL CONSENSUS AND BIAS CORRECTED DATA SUGGESTED RH BETWEEN 15 AND 20 PERCENT WITH WINDS GUSTING TO NEAR 25 MPH BOTH DAYS. && .LBF WATCHES/WARNINGS/ADVISORIES...FREEZE WARNING FROM 10 PM THIS EVENING TO 10 AM CDT SATURDAY FOR NEZ059. && $$ SHORT TERM...CDC AVIATION/EXTENDED...TAYLOR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1151 PM EDT SAT OCT 6 2012 .SYNOPSIS... A WESTERLY FLOW OF CHILLY AIR WILL CONTINUE LAKE EFFECT RAIN SHOWERS EAST OF LAKE ONTARIO TONIGHT WITH THE REST OF THE AREA PARTLY TO MOSTLY CLOUDY. ANOTHER WEAK WAVE OF LOW PRESSURE WILL BRING SOME LIGHT RAIN TO MUCH OF THE REGION SUNDAY ALONG WITH MORE COOL TEMPERATURES. SKIES WILL BEGIN TO CLEAR SUNDAY NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION...ALTHOUGH A FEW LAKE EFFECT SHOWERS MAY LINGER EAST OF THE LAKES. DRY WEATHER WILL RETURN FOR MONDAY AND TUESDAY AS HIGH PRESSURE REMAINS IN PLACE. && .NEAR TERM /THROUGH SUNDAY/... LAKE EFFECT RAIN ONGOING EAST OF LAKE ONTARIO LATE THIS EVENING. OFF LAKE ONTARIO... THIS BAND CONTINUES TO REMAIN FAIRLY WELL ORGANIZED. KTYX RADAR SHOWING A NEARLY CONTINUOUS LINE OF PRECIP EAST-SOUTHEAST OF LAKE ONTARIO. LIGHT TO OCCASIONALLY MODERATE RAINFALL IS ONGOING ACROSS NORTHERN OSWEGO AND SOUTHERN LEWIS COUNTIES. JEFFERSON AND NORTHERN LEWIS REMAIN DRY NORTH OF THE BAND. WITH THIS BAND LOCATED FURTHER AWAY FROM THE SURFACE RIDGING ACROSS WNY IT WILL LIKELY CONTINUE TO STAY ORGANIZED WELL INTO THE OVERNIGHT HOURS. 00Z NAM BUFKIT INDICATED STILL CLOSE TO 10KFT FOR LAKE EL`S AND 400 J/KG OF LAKE INDUCED CAPE. STILL EXPECT THE BAND FOR RAIN TO CONTINUE TO MOVE SOUTHWARD OVER THE NEXT FEW HOURS. THE LATEST HRRR AND LOCAL WRF MODELS ARE STILL IN AGREEMENT WITH THIS IDEA BUT ARE VERIFYING A LITTLE TO FAR SOUTH COMPARED TO CURRENT RADAR. THE BAND WILL EVENTUALLY LIE PARALLEL WITH THE SOUTHEASTERN SHORELINE OF LAKE ONTARIO LATE TONIGHT WITH MOST OF THE RAINFALL OCCURRING ACROSS OSWEGO COUNTY WITH PORTIONS OF NORTHERN CAYUGA AND NORTHEASTERN WAYNE COUNTIES ALSO CATCHING SOME LIGHT RAIN. LATE TONIGHT INTO SUNDAY MORNING AS FLOW BEGINS TO WEAKEN...LAND BREEZE CONVERGENCE IS FORECAST TO INCREASE ALONG THE SOUTH SHORE OF THE LAKE...WHICH MAY PRODUCE ANOTHER PERIOD OF MORE ORGANIZED LAKE EFFECT AT THE SOUTHEAST CORNER OF THE LAKE. BY THIS TIME THE FLOW WILL BE MUCH WEAKER...SO THE BAND SHOULD TEND TO HUG THE LAKESHORE MORE AND NOT EXTEND VERY FAR INLAND. FINALLY BY MIDDAY SUNDAY THE BOUNDARY LAYER FLOW BECOMES LIGHT ENOUGH TO ALLOW THE BAND TO TEA KETTLE AND RETRACT BACK OUT OVER THE LAKE. INSTABILITY IS A LITTLE GREATER OFF LAKE ONTARIO...AND THE BAND MAY LAST LONGER...SO EXPECT RAINFALL POTENTIAL OF A QUARTER TO HALF INCH HERE...WITH THE GREATEST AMOUNTS ACROSS CENTRAL AND SOUTHERN OSWEGO COUNTY. OFF LAKE ERIE... THE BAND EAST OF THE LAKE HAS BROKEN APART. 850 MB TEMPS ARE PLENTY COLD ENOUGH (-2C OFF THE 00Z KBUF SOUNDING) BUT SURFACE RIDGING HAS BUILT ACROSS MUCH OF WESTERN NY WITH A STRONG SURFACE HIGH CENTERED OVER THE CENTRAL PLAINS. THIS SURFACE RIDGING HAS LOWERED EQUILIBRIUM LEVELS DOWN TO AROUND 7000 FT WHICH IS MUCH TOO SHALLOW TO SUPPORT AND RAIN IN ADDITION TO THE SURFACE RIDGING IN PLACE. SUNDAY MORNING THERE MAY BE A BRIEF RESURGENCE OF LAKE EFFECT ORGANIZATION AS BOUNDARY LAYER FLOW BECOMES A LITTLE MORE WESTERLY. THIS WILL BE SHORT LIVED HOWEVER AS LOW LEVEL FLOW BECOMES VERY LIGHT BY LATE MORNING...WITH ANY REMAINING LAKE EFFECT TENDING TO TEA KETTLE OUT OVER THE LAKE AND NOT EXTEND INLAND. OUTSIDE OF THE LAKE EFFECT...MOST LOCATIONS WILL SEE PARTLY TO MOSTLY CLOUDY SKIES. LATEST IR IMAGERY SHOWS LAKE EFFECT CLOUDS OVER MUCH OF WNY AND WITHIN THE BAND EAST OF LAKE ONTARIO. ONLY CLEAR SPOTS AT 03Z WERE ACROSS CNY. MID LEVEL CLOUDS CAN ALSO BE SEEN ON IR STREAMING NORTHEAST ACROSS WESTERN PA. THESE WILL INCREASE IN COVERAGE ACROSS WESTERN NY AHEAD OF A DEVELOPING SURFACE WAVE. SUNDAY...FOLLOWING ANY LINGERING LAKE EFFECT IN THE MORNING...OUR ATTENTION TURNS BACK TO THE SYNOPTIC SCALE. LATEST SHORT TERM MODEL GUIDANCE SWINGS A STRONG SHORTWAVE THROUGH THE MEAN LONGWAVE TROUGH POSITION...CROSSING THE OHIO VALLEY AND PENNSYLVANIA DURING THE AFTERNOON. THIS WILL INTERACT WITH A FRONTAL ZONE TO OUR SOUTH AND PRODUCE A BAROCLINIC LEAF...WHICH WILL ACT TO INCREASE DIFFERENTIAL THERMAL ADVECTION AND ISENTROPIC UPGLIDE ACROSS THE LOWER LAKES. THIS WILL BRING THICKENING AND LOWERING CLOUD COVER DURING THE DAY WITH A MORE WIDESPREAD LIGHT RAIN DEVELOPING BY MIDDAY OR EARLY AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN TIER AND FINGER LAKES WHERE UP TO A QUARTER INCH MAY FALL. FARTHER NORTH...EXPECT THE NORTHERN EDGE OF THE RAIN SHIELD TO CLIP THE NIAGARA FRONTIER EAST TO ROCHESTER AND THE TUG HILL REGION WITH A LITTLE LIGHT RAIN IN THE AFTERNOON. THE THICKENING CLOUD COVER AND DEVELOPING RAIN WILL BRING ANOTHER CHILLY DAY...WITH THE LOWER ELEVATIONS ONLY TOPPING OUT IN THE LOWER 50S AT BEST...WITH MID TO UPPER 40S ACROSS HIGHER TERRAIN. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... THE MAIN CONCERN FOR THE SUNDAY NIGHT THROUGH TUESDAY NIGHT PERIOD IS THE POTENTIAL OF FROST...OR A WIDESPREAD FREEZE. THIS WOULD BE A GOOD TIME TO ISSUE A FREEZE WATCH FOR SUNDAY NIGHT IF CONFIDENCE WAS HIGH ENOUGH...BUT THERE IS TOO MUCH UNCERTAINTY ABOUT CLOUD COVER AND RESULTING LOW TEMPERATURES AT THIS TIME. A SHORTWAVE CURRENTLY MOVING INTO NE WILL BE IN THE PROCESS OF MOVING THROUGH THE LOWER GREAT LAKES REGION BY SUNDAY AFTERNOON AND EVENING. RAIN ACCOMPANYING THIS SYSTEM WILL MOST LIKELY AFFECT /AT LEAST/ THE SOUTHERN TIER AND PA BEFORE MOVING EAST DURING SUNDAY NIGHT AS THE SURFACE BASED COASTAL LOW NEAR DELMARVA MOVES FURTHER OFFSHORE. THE END RESULT TOWARD MONDAY MORNING WILL BE CLOUDS OVERHEAD MOVING OFF TO THE EAST...WITH A GOOD CHANCE FOR HIGH CLOUD COVER AT LEAST OVER THE EASTERN LAKE ONTARIO REGION. IN ADDITION...THERE SHOULD BE SOME ONGOING LAKE EFFECT RAIN SHOWERS EAST OF THE LAKES OVERNIGHT...WITH CLOUDS SPREADING INTO THE HIGHER TERRAIN EAST OF LAKE ONTARIO AND INTO THE SOUTHERN TIER...THE EXACT LOCATION THAT WOULD NORMALLY BE THE COLDEST PLACES IN WESTERN NY. A FREEZE IS POSSIBLE ON THE FRINGES OF ANY LAKE BANDS AND/OR HIGHER CLOUD COVER...BUT AT THIS TIME IT IS TOO UNCERTAIN AS TO HOW WIDESPREAD THE CLOUD COVER WILL BE. WILL THEREFORE ADD IN SOME FROST INTO THE FORECAST FOR AREAS OUTSIDE OF ANTICIPATED THICKER CLOUD COVER...BUT KEEP TEMPERATURES ABOVE THE FREEZING MARK FOR NOW. ON MONDAY ANY LAKE EFFECT SHOULD QUICKLY END DURING THE MORNING WITH HIGH PRESSURE MOVING INTO THE NORTHEAST. MONDAY NIGHT WILL FEATURE MOSTLY CLEAR SKIES...SO ALTHOUGH TEMPERATURES ALOFT WILL WARM A BIT OVER 24 HOURS...THERE WILL ONCE AGAIN BE A LOW CHANCE FOR SOME FROST OR FREEZING CONDITIONS DUE TO RADIATIONAL COOLING. WILL HAVE A SLIGHTLY LARGER AREA COVERED BY FROST FOR LATE MONDAY NIGHT IN THE TRADITIONAL INLAND LOCATIONS...PRIMARILY THE SOUTHERN TIER AND WELL EAST OF LAKE ONTARIO. QUIET WEATHER IS EXPECTED FOR TUESDAY WITH A CONTINUED WARMING TREND...WITH MAX TEMPERATURES APPROACHING NORMAL VALUES FOR THIS TIME OF YEAR. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE REX BLOCK IN PLACE OVER THE EASTERN PACIFIC WILL REMAIN IN PLACE OR V-E-R-Y SLOWLY MOVE INTO THE WESTERN US THE COURSE OF NEXT WEEK. THEREFORE WE NEED TO LOOK ABOVE BC...NEAR THE TOP OF THE RIDGE FOR THE NEXT FEATURE OF INTEREST. MEDIUM RANGE GUIDANCE HAS BEEN VERY CONSISTENT BRING THE NEXT FEATURE DOWN THROUGH ALBERTA AND SASKATCHEWAN EARLY NEXT WEEK...WITH A SURFACE LOW REMAINING IN CA AND PIVOTING AROUND HUDSON BAY WHILE AN ASSOCIATED COLD FRONT SWEEPS ACROSS THE GREAT LAKES REGION AND ACROSS NYS ON WEDNESDAY. THERE IS SOME UNCERTAINTY AS TO TIMING WITH THE FRONT/PRECIPITATION...WITH RAIN POSSIBLE EITHER WEDNESDAY OR WEDNESDAY NIGHT. WILL KEEP FORECAST GENERALLY UNCHANGED FOR NOW WITH LIKELY RAIN IN THE WEST IN THE AFTERNOON. EXPECT A FAIRLY STRONG RIDGE AFTER THIS FOR THURSDAY WITH DRY WEATHER. THEN ANOTHER FRONT DROPS ACROSS THE REGION DURING THE END OF NEXT WEEK FOR ANOTHER CHANCE OF RAIN. TEMPERATURES DROP QUITE A BIT BEHIND THIS NEXT FRONTAL PASSAGE...WITH 850MB TEMPERATURES DOWN TO -7C EAST OF LAKE ONTARIO. HOWEVER...A FAIRLY STRONG RIDGE WILL ALSO BE IN PLACE BY THE WEEKEND. RIGHT NOW LAKE EFFECT POSSIBILITIES LOOK MINIMAL WITH A LOW LEVEL DRY AIRMASS ACROSS THE LOWER GREAT LAKES REGION. ALTHOUGH THE CURRENT CONCERN FOR A FROST/FREEZE IS FOR SUNDAY OR SUNDAY NIGHT...A BIGGER CONCERN MAY BE NEXT WEEKEND. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... LAKE EFFECT RAIN SHOWERS HAVE ENDED EAST OF LAKE ERIE BUT CONTINUE TO BE WELL ORGANIZED EAST OF LAKE ONTARIO. LAKE EFFECT CLOUDS ARE SPREAD OVER MUCH OF WNY AND EAST OF LAKE ONTARIO. MORE ORGANIZED BAND OF LAKE EFFECT RAIN SHOWERS AND CLOUDS HAVE DEVELOPED. BAND OF RAIN WILL SHIFT SOUTH TOWARD KFZY BY JUST AFTER MIDNIGHT. OCCASIONAL MVFR CIGS AND VIS ALSO POSSIBLE IN LAKE EFFECT. OUTSIDE OF THESE AREAS...CLEAR TO PARTLY CLOUDY SKIES WILL REMAIN MUCH OF THE NIGHT. ON SUNDAY LAKE EFFECT RAIN SHOWERS WILL LINGER THROUGH THE MORNING EAST OF THE LAKES WITH AREAS OF MVFR AND LOCAL IFR. BY AFTERNOON A WEAK WAVE OF LOW PRESSURE WILL PASS BY JUST TO THE SOUTH OF THE REGION. THIS MAY PRODUCE A LITTLE MORE WIDESPREAD LIGHT RAIN...WITH ASSOCIATED MVFR AND LOCAL IFR CONDITIONS ESPECIALLY ACROSS HIGHER TERRAIN. OUTLOOK... MONDAY AND TUESDAY...VFR. WEDNESDAY...AREAS OF MVFR WITH SHOWERS LIKELY. THURSDAY...MAINLY VFR. && .MARINE... WINDS DIMINISHING STEADILY OVERNIGHT AS THE PRESSURE GRADIENT RELAXES ACROSS THE AREA. A SMALL CRAFT ADVISORY REMAINS THROUGH SUNDAY MORNING FOR THE EAST END OF LAKE ONTARIO AS OBSERVATIONS THERE STILL SHOWING 20 TO 25 KT WINDS. A WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE FOR THE REST OF SUNDAY WITH MUCH LIGHTER WINDS...AND THE LIGHT WINDS WILL LAST INTO MONDAY AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE LOWER LAKES. WATERSPOUTS WILL BECOME MORE LIKELY THROUGH SUNDAY MORNING OFF LAKE ONTARIO IN AND NEAR BANDS OF LAKE EFFECT SHOWERS AND CLOUDS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT SUNDAY FOR LOZ043>045. && $$ SYNOPSIS...HITCHCOCK/SMITH NEAR TERM...SMITH SHORT TERM...ZAFF LONG TERM...ZAFF AVIATION...SMITH MARINE...SMITH
AREA FORECAST DISCUSSION...CORRECTED
NWS BINGHAMTON NY
304 PM EDT FRI OCT 5 2012 .SYNOPSIS... A COLD FRONT WORKING OVER OUR REGION THIS AFTERNOON WILL STALL OVERNIGHT. AS THIS OCCURS...A DISTURBANCE WILL MOVE UP THE BOUNDARY BRINGING WITH IT AN INCREASED CHANCE FOR SHOWERS TO MUCH OF CENTRAL NEW YORK AND NORTHEASTERN PENNSYLVANIA. SHOWERS WILL PREVAIL ACROSS MUCH OF THE REGION SATURDAY MORNING BEFORE CONDITIONS BEGIN TO IMPROVE BY LATE SATURDAY AFTERNOON. BEYOND THIS...MUCH COOLER AIR WILL SETTLE INTO THE REGION WITH DAYTIME HIGHS ONLY EXPECTED TO REACH THE UPPER 40S TO LOWER 50S BY SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... AN INDIAN SUMMER DAY PREVAILING ACROSS THE FCST AREA THIS AFTERNOON IN ADVANCE OF A COLD FRONT WHICH CONTINUES TO MAKE SLOW PROGRESS ACROSS THE REGION. SO FAR TEMPS HAVE WARMED WELL INTO THE LOWER TO MIDDLE 70S ACROSS MOST LOCATIONS UNDER PARTLY TO MOSTLY CLOUDY SKIES. AS IS USUALLY THE CASE...VARIOUS FCST MODELS HAVE OVERDONE THE QPF FCST THIS AFTERNOON AS REGIONAL RADARS SHOW THE CLOSEST SHWR ACTIVITY STILL QUITE A WAYS TO THE WEST. THAT SAID...VARIOUS HIGH-RES MODELS TO INCLUDE THE HRRR AND WRF-ARW SUGGEST SHWRS WILL DEVELOP AFTER 20Z AS THE FRONT CONTINUES TO MOVE THROUGH THE AREA. WILL MAINTAIN SLGT CHC-CHC MENTION TO ACCOUNT FOR THIS POSSIBILITY. MAIN FOCUS IN THE NEAR TERM CONTINUES TO BE INCREASING CHANCES FOR PRECIP OVERNIGHT AS WESTERN ONTARIO CLOSED LOW SHORTWAVE ENERGY BEGINS TO DIVE SOUTHEAST WITH TIME. AS HAS BEEN THE TREND IN RECENT DAYS...THE COLD FRONT CURRENTLY WORKING THROUGH THE REGION WILL EVENTUALLY SLOW DOWN AS AN AREA OF LOW PRESSURE BEGINS WORKING NORTH ALONG THE BOUNDARY. ADDITIONALLY THE FRONT IS FCST TO BECOME MORE ANAFRONTISH AS PRECIP BECOMES MORE WIDESPREAD WEST OF THE BOUNDARY AS UPPER ENERGY ARRIVES FROM THE WEST. FOR NOW WILL MAINTAIN HIGH END LIKELY TO CATEGORICAL MENTION ACROSS THE WESTERN ZONES...WITH A GRADUAL SHIFT EAST BY SATURDAY MORNING AS THE FRONT FINALLY BEGINS MOVING ONCE AGAIN. FOR SATURDAY...EXPECT WIDESPREAD RAINS IN THE MORNING WITH ACTIVITY GRADUALLY TAPERING OFF FROM WEST TO EAST BY LATE MORNING/EARLY AFTERNOON. THE HEAVIEST RAINS WILL FALL ACROSS THE WESTERN ZONES WHERE TOTAL QPF VALUES MAY APPROACH 1 INCH. FURTHER SOUTH AND EAST...THE FASTER FRONTAL MOVEMENT WILL RESULT IN MUCH LOWER PRECIP AMOUNTS WITH QPF TOTALS LARGELY REMAINING UNDER A QUARTER TO HALF INCH AT BEST. OVERNIGHT TEMPS TONIGHT WILL REMAIN ON THE WARM SIDE WITH VALUES FALLING ONLY INTO THE UPPER 40S TO LOWER 50S. COLD AIR ADVECTION EXPECTED TO START TOMORROW WHICH COMBINED WITH CLOUDS AND PRECIP SHOULD KEEP HIGHS LARGELY IN THE 50S. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... UNSETTLED CONDITIONS TO PERSIST RIGHT THROUGH THE START OF THE SHORT TERM PERIOD AS REGION REMAINS IN BROAD CYCLONIC FLOW ALOFT. MAIN ATTENTION BY SATURDAY NIGHT WILL BE THE POSSIBILITIES FOR DEVELOPING LAKE EFFECT ACTIVITY DOWNWIND OF LAKE ONTARIO AS COLD AIR COMBINED WITH A FAIRLY LONG WESTERLY FETCH CREATES MARGINAL LAKE EFFECT CONDITIONS. INSPECTION OF SEVERAL FCST SOUNDINGS SUGGESTS BEST POTENTIAL FOR LAKE EFFECT SHWR ACTIVITY WILL BE FROM THE SOUTHERN TUG HILL SOUTH THROUGH THE WESTERN MOHAWK VALLEY AS FLOW WILL TAKE ON A 280-290 DEGREE CONFIGURATION. INVERSION HEIGHTS BY 12Z SUN WILL BORDER NEAR 10 KFT WITH INCREASING LAKE GENERATED INSTABILITY EARLY SUN AS COOLER AIR CONTINUES TO FILTER INTO THE REGION. MAIN QUESTIONS REMAIN JUST HOW FAR SOUTH THE DEVELOPING BAND IS ABLE TO EXTEND AS THE NAM MAINTAINS ALMOST A PURE WESTERLY WIND COMPONENT WHILE THE GFS SUGGESTS A BIT MORE OF A NORTHWESTERLY CONFIGURATION. FOR NOW...HAVE DECIDED TO EXTEND PRECIP MENTION A BIT FURTHER SOUTH THAN PREVIOUSLY FCST TO INCLUDE THE GREATER SYR AREA. BIG QUESTIONS STILL REMAIN WITH THE NEXT SYNOPTIC SYSTEM PROGGED TO IMPACT OUR AREA BY SUN AFTERNOON. MAIN CULPRIT WILL BE THE NEXT NORTHERN STREAM PIECE OF ENERGY WHICH IS EXPECTED TO DIVE SOUTHEAST TOWARDS THE EAST COAST AND INDUCE SFC CYCLOGENESIS OFF THE COAST OF VIRGINA BEACH. WITH TIME ON SUN THIS FEATURE WILL MOVE NORTHEAST UP THE COAST WITH INCREASED CHANCES FOR RAIN TO THE CENTRAL MID-ATLANTIC TO INCLUDE PARTS OF OUR FCST AREA. RIGHT NOW THE GFS AND ECMWF AND THE FARTHEST EAST WITH THE SFC LOW WHILE THE NAM REMAINS THE FURTHEST WEST. UNDER THE GFS AND ECMWF/S SCENARIO...THE BULK OF RAIN WOULD REMAIN SOUTH AND EAST WHILE THE NAM SOLUTION SUGGESTS INCREASING RAIN CHANCES FOR ALMOST THE ENTIRE CWA. FOR NOW BASED ON THE AMOUNT OF UNCERTAINTIES THAT EXIST...WILL MAINTAIN A SLGT CHC TO CHC MENTION THROUGH SUN AFTERNOON. BEYOND THIS...SOME POTENTIAL FOR REDEVELOPING LAKE EFFECT ACTIVITY WILL EXIST EAST OF LAKE ONTARIO SUN NIGHT/EARLY MON. NOT OVERLY OPTIMISTIC AT THIS POINT AS SFC RIDGING AND AN INFLUX OF DRIER AIR WILL QUICKLY BUILD IN OVERNIGHT AS HIGH PRESSURE SETTLES OVER THE REGION. DRY CONDITIONS EXPECTED ON MON AS HIGH PRESSURE REMAINS IN CONTROL. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... 130 PM UPDATE...MED RANGE MODELS INDICATE SFC HIPRES OVR CWA BY 00Z TUESDAY. ZONAL FLOW AT H5 WL KEEP MAJOR WX SYSTEMS FM MVG IN EARLY IN THE WEEK. THIS WL CHANGE ON WED AS SFC LOW DVLPS ACRS CNTRL GREAT LKS IN CONJUNCTION WITH H5 TROF APPCHG THE AREA AND SPREADING PCPN INTO THE REGION AFTER 12Z WED. AS THIS LOW EXITS TO THE EAST WED NGT EXPECT LK EFFECT SHOWERS POTENTIALLY MIXED WITH SNOW TO BE THE DOMINANT WX FEATURE THUR MRNG. THE NEXT SYSTEM WL SKIRT ACRS ON FRIDAY WITH ANOTHER CHC FOR RA/SN MIX BHND THIS LOW ON FRI MRNG. H8 TEMPS WL DROP TO BLO -3C AFTER 06Z THUR AND 12Z FRI. THIS WL KEEP LOW TEMPS IN THE LOW-MID 30S BOTH MRNGS. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... 130 PM UPDATE...GNRLY VFR ACRS TERMINALS THIS AFTERNOON WILL GIVE WAY TO MVFR AND POTENTIAL IFR OVERNIGHT AS A COLD FRONT APPROACHES THE AREA FROM THE WEST. AREA OF RAIN IS ENTERING WESTERN NEW YORK AT THIS TIME AND WILL POTENTIALLY AFFECT NY TERMINALS FROM 20Z-24Z TODAY. NO RESTRICTIONS EXPECTED WITH THIS PRECIPITATION. WIDESPREAD RAIN WILL MOVE INTO TERMINALS WELL AFTER 08Z WITH PREDOMINANT MVFR VSBYS/CIGS SETTLING IN FROM NORTH TO SOUTH. POTENTIAL EXISTS FOR IFR CIGS TOWARD 12Z. WINDS OUT OF THE SOUTHWEST THIS AFTERNOON AROUND 5KTS WILL QUICKLY GIVE WAY TO NORTHWEST WINDS BEHIND FRONT AT AROUND 10KTS BETWEEN 10Z-14Z. OUTLOOK... SAT NIGHT TO SUN...SCT MVFR -SHRA ACROSS NORTHERN TERMINALS. SUN NIGHT TO MON...MAINLY VFR ACROSS NY TERMINALS. SCT MVFR POSSIBLE SUN NIGHT WIDELY SCATTERED -SHRA ACRS NEPA. TUE...VFR. WED...POTENTIAL MVFR IN SCATTERED SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...CMG NEAR TERM...CMG SHORT TERM...CMG LONG TERM...PVN AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
303 PM EDT FRI OCT 5 2012 .SYNOPSIS... A COLD FRONT WORKING OVER OUR REGION THIS AFTERNOON WILL STALL OVERNIGHT. AS THIS OCCURS...A DISTURBANCE WILL MOVE UP THE BOUNDARY BRINGING WITH IT AN INCREASED CHANCE FOR SHOWERS TO MUCH OF CENTRAL NEW YORK AND NORTHEASTERN PENNSYLVANIA. SHOWERS WILL PREVAIL ACROSS MUCH OF THE REGION SATURDAY MORNING BEFORE CONDITIONS BEGIN TO IMPROVE BY LATE SATURDAY AFTERNOON. BEYOND THIS...MUCH COOLER AIR WILL SETTLE INTO THE REGION WITH DAYTIME HIGHS ONLY EXPECTED TO REACH THE UPPER 40S TO LOWER 50S BY SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... AN INDIAN SUMMER DAY PREVAILING ACROSS THE FCST AREA THIS AFTERNOON IN ADVANCE OF A COLD FRONT WHICH CONTINUES TO MAKE SLOW PROGRESS ACROSS THE REGION. SO FAR TEMPS HAVE WARMED WELL INTO THE LOWER TO MIDDLE 70S ACROSS MOST LOCATIONS UNDER PARTLY TO MOSTLY CLOUDY SKIES. AS IS USUALLY THE CASE...VARIOUS FCST MODELS HAVE OVERDONE THE QPF FCST THIS AFTERNOON AS REGIONAL RADARS SHOW THE CLOSEST SHWR ACTIVITY STILL QUITE A WAYS TO THE WEST. THAT SAID...VARIOUS HIGH-RES MODELS TO INCLUDE THE HRRR AND WRF-ARW SUGGEST SHWRS WILL DEVELOP AFTER 20Z AS THE FRONT CONTINUES TO MOVE THROUGH THE AREA. WILL MAINTAIN SLGT CHC-CHC MENTION TO ACCOUNT FOR THIS POSSIBILITY HOWEVER OVERALL CONFIDENCE REMAINS MARGINAL. MAIN FOCUS IN THE NEAR TERM CONTINUES TO BE INCREASING CHANCES FOR PRECIP OVERNIGHT AS WESTERN ONTARIO CLOSED LOW SHORTWAVE ENERGY BEGINS TO DIVE SOUTHEAST WITH TIME. AS HAS BEEN THE TREND IN RECENT DAYS...THE COLD FRONT CURRENTLY WORKING THROUGH THE REGION WILL EVENTUALLY SLOW DOWN AS AN AREA OF LOW PRESSURE BEGINS WORKING NORTH ALONG THE BOUNDARY. ADDITIONALLY THE FRONT IS FCST TO BECOME MORE ANAFRONTISH AS PRECIP BECOMES MORE WIDESPREAD WEST OF THE BOUNDARY AS UPPER ENERGY ARRIVES FROM THE WEST. FOR NOW WILL MAINTAIN HIGH END LIKELY TO CATEGORICAL MENTION ACROSS THE WESTERN ZONES...WITH A GRADUAL SHIFT EAST BY SATURDAY MORNING AS THE FRONT FINALLY BEGINS MOVING ONCE AGAIN. FOR SATURDAY...EXPECT WIDESPREAD RAINS IN THE MORNING WITH ACTIVITY GRADUALLY TAPERING OFF FROM WEST TO EAST BY LATE MORNING/EARLY AFTERNOON. THE HEAVIEST RAINS WILL FALL ACROSS THE WESTERN ZONES WHERE TOTAL QPF VALUES MAY APPROACH 1 INCH. FURTHER SOUTH AND EAST...THE FASTER FRONTAL MOVEMENT WILL RESULT IN MUCH LOWER PRECIP AMOUNTS WITH QPF TOTALS LARGELY REMAINING UNDER A QUARTER TO HALF INCH AT BEST. OVERNIGHT TEMPS TONIGHT WILL REMAIN ON THE WARM SIDE WITH VALUES FALLING ONLY INTO THE UPPER 40S TO LOWER 50S. COLD AIR ADVECTION EXPECTED TO START TOMORROW WHICH COMBINED WITH CLOUDS AND PRECIP SHOULD KEEP HIGHS LARGELY IN THE 50S. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... UNSETTLED CONDITIONS TO PERSIST RIGHT THROUGH THE START OF THE SHORT TERM PERIOD AS REGION REMAINS IN BROAD CYCLONIC FLOW ALOFT. MAIN ATTENTION BY SATURDAY NIGHT WILL BE THE POSSIBILITIES FOR DEVELOPING LAKE EFFECT ACTIVITY DOWNWIND OF LAKE ONTARIO AS COLD AIR COMBINED WITH A FAIRLY LONG WESTERLY FETCH CREATES MARGINAL LAKE EFFECT CONDITIONS. INSPECTION OF SEVERAL FCST SOUNDINGS SUGGESTS BEST POTENTIAL FOR LAKE EFFECT SHWR ACTIVITY WILL BE FROM THE SOUTHERN TUG HILL SOUTH THROUGH THE WESTERN MOHAWK VALLEY AS FLOW WILL TAKE ON A 280-290 DEGREE CONFIGURATION. INVERSION HEIGHTS BY 12Z SUN WILL BORDER NEAR 10 KFT WITH INCREASING LAKE GENERATED INSTABILITY EARLY SUN AS COOLER AIR CONTINUES TO FILTER INTO THE REGION. MAIN QUESTIONS REMAIN JUST HOW FAR SOUTH THE DEVELOPING BAND IS ABLE TO EXTEND AS THE NAM MAINTAINS ALMOST A PURE WESTERLY WIND COMPONENT WHILE THE GFS SUGGESTS A BIT MORE OF A NORTHWESTERLY CONFIGURATION. FOR NOW...HAVE DECIDED TO EXTEND PRECIP MENTION A BIT FURTHER SOUTH THAN PREVIOUSLY FCST TO INCLUDE THE GREATER SYR AREA. BIG QUESTIONS STILL REMAIN WITH THE NEXT SYNOPTIC SYSTEM PROGGED TO IMPACT OUR AREA BY SUN AFTERNOON. MAIN CULPRIT WILL BE THE NEXT NORTHERN STREAM PIECE OF ENERGY WHICH IS EXPECTED TO DIVE SOUTHEAST TOWARDS THE EAST COAST AND INDUCE SFC CYCLOGENESIS OFF THE COAST OF VIRGINA BEACH. WITH TIME ON SUN THIS FEATURE WILL MOVE NORTHEAST UP THE COAST WITH INCREASED CHANCES FOR RAIN TO THE CENTRAL MID-ATLANTIC TO INCLUDE PARTS OF OUR FCST AREA. RIGHT NOW THE GFS AND ECMWF AND THE FARTHEST EAST WITH THE SFC LOW WHILE THE NAM REMAINS THE FURTHEST WEST. UNDER THE GFS AND ECMWF/S SCENARIO...THE BULK OF RAIN WOULD REMAIN SOUTH AND EAST WHILE THE NAM SOLUTION SUGGESTS INCREASING RAIN CHANCES FOR ALMOST THE ENTIRE CWA. FOR NOW BASED ON THE AMOUNT OF UNCERTAINTIES THAT EXIST...WILL MAINTAIN A SLGT CHC TO CHC MENTION THROUGH SUN AFTERNOON. BEYOND THIS...SOME POTENTIAL FOR REDEVELOPING LAKE EFFECT ACTIVITY WILL EXIST EAST OF LAKE ONTARIO SUN NIGHT/EARLY MON. NOT OVERLY OPTIMISTIC AT THIS POINT AS SFC RIDGING AND AN INFLUX OF DRIER AIR WILL QUICKLY BUILD IN OVERNIGHT AS HIGH PRESSURE SETTLES OVER THE REGION. DRY CONDITIONS EXPECTED ON MON AS HIGH PRESSURE REMAINS IN CONTROL. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... 130 PM UPDATE...MED RANGE MODELS INDICATE SFC HIPRES OVR CWA BY 00Z TUESDAY. ZONAL FLOW AT H5 WL KEEP MAJOR WX SYSTEMS FM MVG IN EARLY IN THE WEEK. THIS WL CHANGE ON WED AS SFC LOW DVLPS ACRS CNTRL GREAT LKS IN CONJUNCTION WITH H5 TROF APPCHG THE AREA AND SPREADING PCPN INTO THE REGION AFTER 12Z WED. AS THIS LOW EXITS TO THE EAST WED NGT EXPECT LK EFFECT SHOWERS POTENTIALLY MIXED WITH SNOW TO BE THE DOMINANT WX FEATURE THUR MRNG. THE NEXT SYSTEM WL SKIRT ACRS ON FRIDAY WITH ANOTHER CHC FOR RA/SN MIX BHND THIS LOW ON FRI MRNG. H8 TEMPS WL DROP TO BLO -3C AFTER 06Z THUR AND 12Z FRI. THIS WL KEEP LOW TEMPS IN THE LOW-MID 30S BOTH MRNGS. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... 130 PM UPDATE...GNRLY VFR ACRS TERMINALS THIS AFTERNOON WILL GIVE WAY TO MVFR AND POTENTIAL IFR OVERNIGHT AS A COLD FRONT APPROACHES THE AREA FROM THE WEST. AREA OF RAIN IS ENTERING WESTERN NEW YORK AT THIS TIME AND WILL POTENTIALLY AFFECT NY TERMINALS FROM 20Z-24Z TODAY. NO RESTRICTIONS EXPECTED WITH THIS PRECIPITATION. WIDESPREAD RAIN WILL MOVE INTO TERMINALS WELL AFTER 08Z WITH PREDOMINANT MVFR VSBYS/CIGS SETTLING IN FROM NORTH TO SOUTH. POTENTIAL EXISTS FOR IFR CIGS TOWARD 12Z. WINDS OUT OF THE SOUTHWEST THIS AFTERNOON AROUND 5KTS WILL QUICKLY GIVE WAY TO NORTHWEST WINDS BEHIND FRONT AT AROUND 10KTS BETWEEN 10Z-14Z. OUTLOOK... SAT NIGHT TO SUN...SCT MVFR -SHRA ACROSS NORTHERN TERMINALS. SUN NIGHT TO MON...MAINLY VFR ACROSS NY TERMINALS. SCT MVFR POSSIBLE SUN NIGHT WIDELY SCATTERED -SHRA ACRS NEPA. TUE...VFR. WED...POTENTIAL MVFR IN SCATTERED SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...CMG NEAR TERM...CMG SHORT TERM...CMG LONG TERM...PVN AVIATION...PVN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
143 PM EDT FRI OCT 5 2012 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING AND BRING IN COOLER TEMPERATURES. A TROUGH OF LOW PRESSURE WILL ROTATE ACROSS THE EASTERN GREAT LAKES SATURDAY NIGHT. A RIDGE OF HIGH PRESSURE WILL EXTEND NORTHEAST OVER THE AREA SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE COLD FRONTAL BOUNDARY IS MAKING SLOW PROGRESS ACROSS THE CWA THIS AFTERNOON WITH THE HRRR MODEL HANDLING THE PROGRESSION OF THE SHOWERS RATHER WELL. TEMPERATURES HAVE REACHED NEAR 70 IN THE FAR SOUTHEAST COUNTIES AHEAD OF THE BOUNDARY WITH COOLER READINGS BEHIND THE FRONT. REGIONAL MOSAIC RADAR ALREADY SHOWS MORE SHOWERS OVERSPREADING NORTHERN ILLINOIS AND INDIANA WHICH WILL REACH OHIO THIS EVENING. ONLY MINOR ADJUSTMENTS MADE TO TEMPERATURES. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... COLDEST AIR OF THE SEASON MOVES IN TONIGHT AND STICKS AROUND THROUGH THE WEEKEND. RAIN SHOWERS WILL BE ONGOING DURING THE EVENING AND WILL SLOWLY END FROM WEST TO EAST OVERNIGHT. THERE MAY BE A FEW LINGERING SHOWERS ACROSS THE EAST IN THE MORNING...BUT OVERALL A FAIR BUT COOL WEATHER DAY SATURDAY. WE ARE TALKING HIGHS ONLY IN THE LOWER/MID 50S AFTER MORNING LOWS FROM 38 TO 45. THERE ARE A FEW MORE QUESTIONS ABOUT THE WEATHER FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT YET. OVERALL THERE IS A SECONDARY TROUGH COMING DOWN ACROSS THE GREAT LAKES SATURDAY INTO SATURDAY NIGHT WHILE HIGH PRESSURE BUILDS OVER THE PLAINS AND MIDWEST. ELONGATED TROUGH ALOFT. QUESTIONS WITH HOW MUCH MOISTURE THE GREAT LAKES TROUGH WILL HAVE...ITS TIMING AND THEN HOW MUCH INFLUENCE ONE LAST SHORTWAVE MOVING THROUGH THE MEAN TROUGH WILL HAVE. ECMWF STICKING ITS GROUND AND TAKING A SHARPER SHORTWAVE ACROSS SUNDAY AND BRINGING PRECIP INTO MUCH OF THE AREA. GFS HOLDING ON WITH THE GREAT LAKES TROUGH BEING MORE SIGNIFICANT AND THEN POSSIBLY HAVING TO DEAL WITH SOME LAKE EFFECT/ENHANCED SHOWERS. TIMING AND DIRECTION OF FLOW WILL DETERMINE WHERE THESE SHOWERS WOULD BE. THUNDER COULD ACCOMPANY SOME OF THESE SHOWERS SATURDAY NIGHT INTO SUNDAY OVER THE LAKE WITH LAKE TEMP AND H5 TEMP DIFFERENCE LARGE ENOUGH. SO FOR NOW HAVE SOME GENERIC POPS FOR SAT NIGHT AND SUNDAY. WITH THE CLOUD COVER SHOULD KEEP SAT NIGHT LOWS IN THE UPPER 30S/AROUND 40. COULD A SLUSHY FLAKE OR TWO MIX IN IN THE HIGHEST ELEVATIONS...POSSIBLY...BUT WITH ALL THE UNCERTAINTY WILL NOT MENTION YET. HAVE LEANED EVER SO SLIGHTLY TOWARD THE ECMWF AND THEREFORE HAVE KEPT THE HIGHS SUNDAY LOWER THAN THE GFS MOS GUIDANCE...MID AND UPPER 40S ONLY. BY SUNDAY NIGHT INTO MONDAY HIGH PRESSURE BUILDING INTO THE LOCAL AREA. SUNDAY NIGHT STILL LOOKS TO BE THE COLDEST NIGHT AND HAVE TEMPS IN THE LOWER/MID 30S. A FROST/FREEZE IS POSSIBLE AWAY FROM THE LAKE AND WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER OUTLOOK. MONDAY FAIR WITH HIGH PRESSURE BEGINNING TO SHIFT EAST. THIS WILL ALLOW TEMPS TO RECOVER INTO THE 50S FOR HIGHS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A COLD FRONT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY. CONTINUING WITH THE THREAT OF SHOWERS TUESDAY NIGHT. THE POPS MAY NEED TO BE ADJUSTED A LITTLE...HIGHER. WITH TIMING ISSUES WILL NOT MAKE ANY CHANGES NOW...BECAUSE THE IDEA IS RIGHT. SOME LAKE INDUCED SHOWERS COULD OCCUR WEDNESDAY NIGHT BUT THE HIGH BUILDS IN FAST AND STRONG...SO WILL KEEP THURSDAY DRY. TEMPERATURES WILL BE BELOW NORMAL. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... COLD FRONT CONTINUES TO SLOWLY MOVE THROUGH THE FORECAST AREA. WIDESPREAD RAIN HAS DEVELOPED IN ADVANCE OF THE FRONT. CEILING HEIGHTS AROUND 1.5 KFT ARE OCCURRING WITH THE HEAVIEST RAIN AND OTHER CEILINGS AROUND 2.5 KFT SURROUND THIS AREA. VISIBILITIES IN THE RAIN ARE GENERALLY RANGING FROM 2 TO 4 MILES. EXPECT THIS TREND TO CONTINUE THIS AFTERNOON AND INTO THE EVENING AS MORE PRECIPITATION IS FORMING TO THE WEST. MODELS SHOW THE PRECIPITATION ENDING AFTER MIDNIGHT TONIGHT. SLOWLY DRIER AIR WILL BUILD OVER THE AREA ON SATURDAY. CLOUDS MAY LINGER OVER THE EASTERN AREAS AS COLD AIR MOVES OVER THE LAKES ON SATURDAY. WINDS WILL GENERALLY MAINTAIN A WESTERLY DIRECTION AND MAY VARY BETWEEN SOUTHWEST TO NORTHWEST DURING THE PERIOD. .OUTLOOK...NON-VFR SATURDAY AFTERNOON INTO SUNDAY...ESPECIALLY OVER NORTHEAST OHIO AND NORTHWEST PA. && .MARINE... A COLD FRONT WILL MOVE ACROSS LAKE ERIE THIS MORNING. THE WINDS WILL BECOME WEST AFTER FRONTAL PASSAGE AND THEN MAY DECREASE SOME THIS EVENING BEFORE PICKING UP AGAIN BY DAYBREAK SATURDAY. IT WILL BE MAINLY A WEST WIND SO WILL ISSUE A SMALL CRAFT ADVISORY FROM LAKE COUNTY EAST UNTIL EARLY SUNDAY MORNING. THE WESTERLY FLOW SHOULD CAUSE WAVES TO INCREASE TO 3 TO 5 FEET THIS MORNING...THEY WILL PROBABLY FLUCTUATE AND WILL DEFINITELY BE AT SMALL CRAFT ADVISORY CRITERIA SATURDAY BEFORE DECREASING SATURDAY NIGHT. THE SMALL CRAFT MAY HAVE TO BE EXTENDED A LITTLE WEST ON SATURDAY AS THE WINDS WILL BE STRONGEST AND MOST CONSISTENT THEN. WATERSPOUTS WILL BE POSSIBLE ON THE LAKE MAINLY SATURDAY AFTERNOON INTO SATURDAY NIGHT. WILL MENTION IN HAZARDOUS WEATHER OUTLOOK. A RIDGE WILL BE BUILDING INTO THE OHIO VALLEY SUNDAY AND AS THE RIDGE BECOMES ESTABLISHED BY MONDAY MORNING THE WINDS WILL BECOME SOUTHWEST ON THE LAKE. THE SOUTHWEST FLOW WILL INCREASE MONDAY AND TUESDAY AND THE SPEEDS COULD GET CLOSE TO 20 TO 25 KNOTS NEEDING A SMALL CRAFT ADVISORY...THIS WILL HAVE TO BE MONITORED. A COLD FRONT MOVES ACROSS THE LAKE LATE TUESDAY NIGHT AND WEDNESDAY...ANOTHER SMALL CRAFT WILL LIKELY BE NEEDED. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT SUNDAY FOR LEZ147>149. && $$ SYNOPSIS...OUDEMAN NEAR TERM...REL SHORT TERM...OUDEMAN LONG TERM...KIELTYKA AVIATION...GARNET MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1234 PM EDT FRI OCT 5 2012 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING AND BRING IN COOLER TEMPERATURES. A TROUGH OF LOW PRESSURE WILL ROTATE ACROSS THE EASTERN GREAT LAKES SATURDAY NIGHT. A RIDGE OF HIGH PRESSURE WILL EXTEND NORTHEAST OVER THE AREA SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE COLD FRONTAL BOUNDARY IS MAKING SLOW PROGRESS ACROSS THE CWA THIS AFTERNOON WITH THE HRRR MODEL HANDLING THE PROGRESSION OF THE SHOWERS RATHER WELL. TEMPERATURES HAVE REACHED NEAR 70 IN THE FAR SOUTHEAST COUNTIES AHEAD OF THE BOUNDARY WITH COOLER READINGS BEHIND THE FRONT. REGIONAL MOSAIC RADAR ALREADY SHOWS MORE SHOWERS OVERSPREADING NORTHERN ILLINOIS AND INDIANA WHICH WILL REACH OHIO THIS EVENING. ONLY MINOR ADJUSTMENTS MADE TO TEMPERATURES. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... COLDEST AIR OF THE SEASON MOVES IN TONIGHT AND STICKS AROUND THROUGH THE WEEKEND. RAIN SHOWERS WILL BE ONGOING DURING THE EVENING AND WILL SLOWLY END FROM WEST TO EAST OVERNIGHT. THERE MAY BE A FEW LINGERING SHOWERS ACROSS THE EAST IN THE MORNING...BUT OVERALL A FAIR BUT COOL WEATHER DAY SATURDAY. WE ARE TALKING HIGHS ONLY IN THE LOWER/MID 50S AFTER MORNING LOWS FROM 38 TO 45. THERE ARE A FEW MORE QUESTIONS ABOUT THE WEATHER FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT YET. OVERALL THERE IS A SECONDARY TROUGH COMING DOWN ACROSS THE GREAT LAKES SATURDAY INTO SATURDAY NIGHT WHILE HIGH PRESSURE BUILDS OVER THE PLAINS AND MIDWEST. ELONGATED TROUGH ALOFT. QUESTIONS WITH HOW MUCH MOISTURE THE GREAT LAKES TROUGH WILL HAVE...ITS TIMING AND THEN HOW MUCH INFLUENCE ONE LAST SHORTWAVE MOVING THROUGH THE MEAN TROUGH WILL HAVE. ECMWF STICKING ITS GROUND AND TAKING A SHARPER SHORTWAVE ACROSS SUNDAY AND BRINGING PRECIP INTO MUCH OF THE AREA. GFS HOLDING ON WITH THE GREAT LAKES TROUGH BEING MORE SIGNIFICANT AND THEN POSSIBLY HAVING TO DEAL WITH SOME LAKE EFFECT/ENHANCED SHOWERS. TIMING AND DIRECTION OF FLOW WILL DETERMINE WHERE THESE SHOWERS WOULD BE. THUNDER COULD ACCOMPANY SOME OF THESE SHOWERS SATURDAY NIGHT INTO SUNDAY OVER THE LAKE WITH LAKE TEMP AND H5 TEMP DIFFERENCE LARGE ENOUGH. SO FOR NOW HAVE SOME GENERIC POPS FOR SAT NIGHT AND SUNDAY. WITH THE CLOUD COVER SHOULD KEEP SAT NIGHT LOWS IN THE UPPER 30S/AROUND 40. COULD A SLUSHY FLAKE OR TWO MIX IN IN THE HIGHEST ELEVATIONS...POSSIBLY...BUT WITH ALL THE UNCERTAINTY WILL NOT MENTION YET. HAVE LEANED EVER SO SLIGHTLY TOWARD THE ECMWF AND THEREFORE HAVE KEPT THE HIGHS SUNDAY LOWER THAN THE GFS MOS GUIDANCE...MID AND UPPER 40S ONLY. BY SUNDAY NIGHT INTO MONDAY HIGH PRESSURE BUILDING INTO THE LOCAL AREA. SUNDAY NIGHT STILL LOOKS TO BE THE COLDEST NIGHT AND HAVE TEMPS IN THE LOWER/MID 30S. A FROST/FREEZE IS POSSIBLE AWAY FROM THE LAKE AND WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER OUTLOOK. MONDAY FAIR WITH HIGH PRESSURE BEGINNING TO SHIFT EAST. THIS WILL ALLOW TEMPS TO RECOVER INTO THE 50S FOR HIGHS. && .LONG TERM /TUESDAY THROUGH THURSDAY/... A COLD FRONT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY. CONTINUING WITH THE THREAT OF SHOWERS TUESDAY NIGHT. THE POPS MAY NEED TO BE ADJUSTED A LITTLE...HIGHER. WITH TIMING ISSUES WILL NOT MAKE ANY CHANGES NOW...BECAUSE THE IDEA IS RIGHT. SOME LAKE INDUCED SHOWERS COULD OCCUR WEDNESDAY NIGHT BUT THE HIGH BUILDS IN FAST AND STRONG...SO WILL KEEP THURSDAY DRY. TEMPERATURES WILL BE BELOW NORMAL. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... COLD FRONT WILL MOVE THROUGH MFD AND CLE AROUND 12Z AND ERI AND YNG 15Z-16Z. A BRIEF PERIOD OF CEILINGS AROUND 1500 FEET WILL OCCUR AFTER THE FRONTAL PASSAGE. THE RAIN IS ON THE OH AND INDIANA LINE AND MOVING EAST. THE MODELS ALL HAVE THE SAME IDEA BUT DIFFERENCES IN THE MOISTURE AND TIMING. CONDITIONS SHOULD DROP TO MVFR...THE SREF SEEMS TO HAVE A GOOD HANDLE ON THINGS. CONFIDENCE IN THE TIMING OF THE LOWERING CONDITIONS IS MODERATE AT THIS TIME. ANY IFR CONDITIONS SHOULD BE BRIEF AND COULD BE EITHER VISIBILITY OR CEILINGS. CONDITIONS WILL BEGIN IMPROVING TO VFR FROM THE NORTHWEST LATE THIS EVENING. BY DAYBREAK SATURDAY THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 19C. WITH THE FLOW WESTERLY THE SHOWERS SHOULD BE MAINLY EAST OF CLE. .OUTLOOK...NON-VFR SATURDAY AFTERNOON INTO SUNDAY...ESPECIALLY OVER NORTHEAST OHIO AND NORTHWEST PA. && .MARINE... A COLD FRONT WILL MOVE ACROSS LAKE ERIE THIS MORNING. THE WINDS WILL BECOME WEST AFTER FRONTAL PASSAGE AND THEN MAY DECREASE SOME THIS EVENING BEFORE PICKING UP AGAIN BY DAYBREAK SATURDAY. IT WILL BE MAINLY A WEST WIND SO WILL ISSUE A SMALL CRAFT ADVISORY FROM LAKE COUNTY EAST UNTIL EARLY SUNDAY MORNING. THE WESTERLY FLOW SHOULD CAUSE WAVES TO INCREASE TO 3 TO 5 FEET THIS MORNING...THEY WILL PROBABLY FLUCTUATE AND WILL DEFINITELY BE AT SMALL CRAFT ADVISORY CRITERIA SATURDAY BEFORE DECREASING SATURDAY NIGHT. THE SMALL CRAFT MAY HAVE TO BE EXTENDED A LITTLE WEST ON SATURDAY AS THE WINDS WILL BE STRONGEST AND MOST CONSISTENT THEN. WATERSPOUTS WILL BE POSSIBLE ON THE LAKE MAINLY SATURDAY AFTERNOON INTO SATURDAY NIGHT. WILL MENTION IN HAZARDOUS WEATHER OUTLOOK. A RIDGE WILL BE BUILDING INTO THE OHIO VALLEY SUNDAY AND AS THE RIDGE BECOMES ESTABLISHED BY MONDAY MORNING THE WINDS WILL BECOME SOUTHWEST ON THE LAKE. THE SOUTHWEST FLOW WILL INCREASE MONDAY AND TUESDAY AND THE SPEEDS COULD GET CLOSE TO 20 TO 25 KNOTS NEEDING A SMALL CRAFT ADVISORY...THIS WILL HAVE TO BE MONITORED. A COLD FRONT MOVES ACROSS THE LAKE LATE TUESDAY NIGHT AND WEDNESDAY...ANOTHER SMALL CRAFT WILL LIKELY BE NEEDED. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EDT SUNDAY FOR LEZ147>149. && $$ SYNOPSIS...OUDEMAN NEAR TERM...REL SHORT TERM...OUDEMAN LONG TERM...KIELTYKA AVIATION...KIELTYKA MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS TULSA OK
1151 PM CDT THU OCT 4 2012 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. FOR THE 6Z TAFS... RAIN SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED TO AFFECT MUCH OF THE AREA OVERNIGHT. CEILINGS ARE EXPECTED TO FALL TO MVFR LEVELS... WITH LIGHT DRIZZLE PERSISTING THROUGHOUT MUCH OF THE DAY FRIDAY. CONDITIONS WILL SLOWLY IMPROVE FROM THE NORTH THROUGH THE AFTERNOON AND EVENING. && .PREV DISCUSSION... /ISSUED 756 PM CDT THU OCT 4 2012/ DISCUSSION... SHALLOW FRONT CONTINUES TO WEDGE ITS WAY SOUTH...LOCATED FROM GROVE TO ADA AT 00Z. THE SOUTHWARD PUSH SHOULD HALT BY LATE TONIGHT IN THE ELEVATED TERRAIN OF SOUTHEAST OK AND NORTHWEST AR. THE LATEST DATA CONTINUES TO INDICATE SOME ELEVATED SHOWER AND STORM DVLPMT LATER TONIGHT MAINLY ACROSS NORTHEAST OK. HOWEVER...THE LATEST HRRR ISN`T VERY AGGRESSIVE WITH DVLPMT TONIGHT...WHILE OTHER MODELS SUCH AS THE GFS AND ECMWF SHOW THE HEAVIER QPF NORTH OF THE KANSAS BORDER. THUS...I HAVE TRENDED POPS LOWER AND HAVE REDUCED THUNDER CHANCES TO JUST SCT FOR TONIGHT. UPDATED TEXT PRODUCTS SENT. LACY PREV DISCUSSION... /ISSUED 624 PM CDT THU OCT 4 2012/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. FOR THE 0Z TAFS... A SLOW MOVING COLD FRONT/WIND SHIFT IS CURRENTLY WORKING ITS WAY SOUTHWARD ACROSS THE REGION. NORTHEAST OKLAHOMA SITES HAVE ALREADY SHIFTED TO THE NORTH. KMLC AND ARKANSAS SITES WILL FOLLOW BY 6Z. ARKANSAS SITES WILL HAVE THE BEST POSSIBILITY FOR THUNDERSTORMS EARLY FRIDAY LASTING INTO MID MORNING. WIDESPREAD MVFR CEILINGS ARE EXPECTED IN THE WAKE OF THE FRONT. PREV DISCUSSION... /ISSUED 344 PM CDT THU OCT 4 2012/ DISCUSSION... MUCH ANTICIPATED COLD FRONT HAS ARRIVED IN NORTHEAST OK AND WAS POSITIONED NEAR I-44 AT 3 PM. AT THIS TIME ONLY MODEST PRESSURE RISES NOTED IMMEDIATELY IN ITS WAKE AND THE FRONTS PROGRESS SOUTHEAST WILL BE SLOW WITH THE FRONT LIKELY STALLING AS IT BEGINS TO ENCOUNTER HIGHER TERRAIN. RELATIVELY HIGH DEW POINTS POOLING NEAR THE BOUNDARY IN SOUTHERN OK HAVE RESULTED IN A NARROW AXIS OF INSTABILITY...HOWEVER WARM MID LEVEL TEMPS KEEPING A STRONG CAP IN PLACE AND CLOUD COVER HAS LIMITED SFC HEATING POTENTIAL SOMEWHAT. STILL A SMALL THREAT OF AN ISOLATED STORM DEVELOPING ALONG BOUNDARY BUT BETTER CHANCES ARRIVE LATE THIS EVENING WITH STRENGTHENING WINDS ATOP THE COOL AIR EVENTUALLY RESULTING IN WIDESPREAD ELEVATED THUNDERSTORMS NORTH OF THE FRONT. THE INCREASING DEEP LAYER SHEAR DOES LEND AT LEAST SOME POSSIBILITY TO ORGANIZED STORMS BUT OVERALL SEVERE THREAT LOOKS LOW AT THIS TIME. PROGRESS OF THE FRONT WILL CONTINUE TO BE SLOW THROUGH THE DAY FRIDAY WITH POST FRONTAL SHOWERS AND A FEW THUNDERSTORMS SHIFTING EAST. THIS WILL LIKELY RESULT IN A WIDE RANGE OF HIGH TEMPS ACROSS THE AREA AND A ZONE OF HIGH UNCERTAINTY FROM NW CORNER OF ARKANSAS THROUGH SE OKLAHOMA. IN GENERAL HAVE GONE LOWER THE GUIDANCE FOR MAX TEMPS...WITH EXCEPTION OF THOSE AREAS. BREAK IN PRECIP WILL OCCUR FOR A TIME LATE FRIDAY BEFORE ANOTHER SURGE NORTH OF THE FRONT FRIDAY NIGHT...WHICH BY THIS TIME SHOULD BE SOUTH OF THE RED RIVER AS REINFORCING SHOT OF DEEPER COLD AIR ARRIVES. APPROACHING UPPER LEVEL WAVE FROM THE NORTHWEST WILL KEEP RAIN CHANCES GOING THROUGH SATURDAY WITH TEMPS STRUGGLING TO REACH 50 IN MANY AREAS...AND RECORD LOW MAXES VERY LIKELY AT TUL/FSM. AS THIS WAVE PASSES TO THE NORTH...WILL BEGIN TO SEE SOME CLEARING ACROSS NORTHERN AREAS. POTENTIAL FOR FREEZING TEMPS LOOKING HIGH OVER FAR NORTHERN AREAS...HOWEVER THERE REMAINS SOME UNCERTAINTY AS TO HOW MUCH SKIES WILL CLEAR AND HOW SOON. WITH THIS UNCERTAINTY IN PLACE IN THE 5TH PERIOD OF THE FORECAST WILL NOT ISSUE A FREEZE WATCH YET...BUT SOME HIGHLIGHTS LIKELY TO BE NEEDED FOR SUN MORNING ESPECIALLY GIVEN HOW EARLY IN THE SEASON IT IS. CONTINUED COOL SUNDAY WITH LIGHT WINDS...WHICH COME AROUND SOUTH LATE. HOWEVER...NIT LATE ENOUGH TO KEEP TEMPS FROM FALLING AT OR A LITTLE BELOW FREEZING IN THE MORE SHELTERED VALLEY AREAS TO THE EAST AND SOUTH. A NICE WARM UP WILL OCCUR TUE AHEAD OF ANOTHER APPROACHING FRONT WHICH WILL BRING ANOTHER CHANCE OF PRECIP TO THE AREA WED/THU. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...06
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
908 PM CDT SAT OCT 6 2012 .UPDATE... EXPECT CLOUD COVER TO REMAIN LONGER. LATEST RUC SOUNDINGS HAVE A STRONGER INVERSION JUST ABOVE THE CLOUD DECK AROUND 7 THSD FT. PILOT REPORTS HAVE THE CLOUD THICKNESS AROUND 1 TO 1.5 THSD FT. DVN 00Z UPPER AIR PROFILE HAS A VERY SHALLOW MOIST LAYER. GRB`S IS A LITTLE THICKER. 00Z NAM SOUNDINGS SHOW THE 850 MB MOISTURE REMAINING LONGER AND HAS A RATHER CHAOTIC DRYING. THEREFORE EXPECT CLOUDS TO GRADUALLY THIN...AND SOME BREAKS SHOULD FORM. WILL LEAVE THE FREEZE WARNINGS SINCE TEMPERATURES ARE IN THE MID 30S TO LOWER 40S AND ANY CLEARING WOULD RESULT IN TEMPERATURES DROPPING INTO THE UPPER 20S. HOWEVER DO NOT EXPECT A WIDESPREAD HARD FREEZE DUE TO THE CLOUDS. && .AVIATION/06Z TAFS/... PERSISTENT STRATOCUMULUS DECK AROUND 5 TO 6 THSD FT SHOULD GRADUALLY THIN WITH SOME AREAS BECOMING SCATTERED DURING THE EARLY MORNING. MID LEVEL TROUGH AXIS WILL EXIT FAR SOUTHEAST WISCONSIN AROUND 12 TO 15Z...AND A MORE GENERAL CLEARING IS EXPECTED. && .PREV DISCUSSION... /ISSUED 255 PM CDT SAT OCT 6 2012/ TONIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH. VORTICITY MAXIMUM SLIDING EAST INTO THE AREA MAY BRING SOME SPRINKLES TO THE AREA UNTIL SUNSET...BUT LEFT OUT OF FORECAST WITH LIMITED AREAL COVERAGE EXPECTED. OTHERWISE...BROKEN TO OVERCAST AREA OF CLOUDS OVER THE AREA SHOULD LINGER INTO THE EARLY TO MID EVENING HOURS...WITHIN BROAD CYCLONIC MIDDLE TO UPPER LEVEL FLOW. AREA FORECAST SOUNDINGS AND SHORT TERM MODEL LOW LEVEL MOISTURE PRODUCTS SUPPORT THIS AS WELL. THIS DECK SHOULD SLOWLY MIX OUT LATER THIS EVENING AND OVERNIGHT...AS COLD AIR ADVECTION CONTINUES TO BRING DRIER AIR INTO THE AREA. THE EXPECTED CLEARING LATE TONIGHT WITH THE HIGH PRESSURE RIDGE MOVING INTO THE AREA SHOULD COMBINE WITH LIGHTER WINDS TO BRING A WIDESPREAD FREEZE TO THE ENTIRE AREA...GIVEN EXPECTED LOWS IN THE 20S TO LOWER 30S LAKESIDE. THUS...THE FREEZE WARNING WAS EXPANDED ACROSS THE ENTIRE AREA. MOSTLY SUNNY BUT COOL CONDITIONS ARE THEN EXPECTED SUNDAY...WITH LOWER 50S FOR HIGHS. SUNDAY NIGHT THROUGH MONDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. A MODERATELY STRONG 500MB SHORT WAVE WILL DROP FROM THE LAKE WINNIPEG CANADA REGION LATE SUNDAY NIGHT...CLIPPING NORTHERN MINNESOTA BEFORE ARCING BACK TO THE NORTH MONDAY NIGHT. THERE IS AN ASSOCIATED TRAILING TROF THAT DOES STRETCH BACK TO THE SOUTHWEST...INTO THE NRN TIER OF THE U.S. THE RESULTING SURFACE CYCLOGENESIS IS FAIRLY RAPID...WITH A LOW DEEPENING AND MOVING ALONG THE U.S. CANADIAN BORDER. WE GET INTO THE TIGHT PRESSURE GRADIENT AHEAD OF THE LOW...CONTRASTED AGAINST HIGH PRESSURE OVER THE EAST COAST. THIS PUSHES A NICE THERMAL RIDGE INTO THE REGION...ALONG WITH BRISK/GUSTY WINDS. TEMPS SHOULD RISE INTO THE LOWER AND MAYBE MID 60S. HOWEVER...THINGS ARE EXPECTED TO BE DRY THROUGH THIS PERIOD. MONDAY NIGHT THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. THE 500MB TROF THEN DIGS INTO THE GREAT LAKES AS ANOTHER SHOT OF ENERGY DIVES INTO THE BACK SIDE OF THE LEAD SHORT WAVE MENTIONED ABOVE. THIS FINALLY KICKS OUT THE SFC LOW WITH THE TRAILING COLD FRONT SWEEPING THROUGH THE AREA TUESDAY INTO TUESDAY NIGHT. THE MODELS ARE IN PRETTY GOOD AGREEMENT HERE WITH DRAGGING SOME LIGHT QPF ACROSS THE AREA. A LITTLE CONCERNED THOUGH ABOUT THE EVENTUAL MOISTURE PROFILE WITH THE FRONTAL PASSAGE. THERE IS SOME LACK OF MOISTURE IN THE LOWER LEVELS...AND WITH THE PARENT LOW SO FAR TO THE NORTH...WE COULD SEE SOME WEAKENING OF FORCING/LIFT. PREFER TO WAIT ANOTHER CYCLE BEFORE UPPING POPS ANY HIGHER. WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH. HIGH PRESSURE BUILDS IN BEHIND THE FRONT. COOLER LOW TO MID 50S EXPECTED WITH SOME SUNSHINE. THURSDAY AND FRIDAY...FORECAST CONFIDENCE IS MEDIUM. ANOTHER WEAK SFC LOW PASSES ACROSS THE NORTHERN GREAT LAKES ON THURSDAY...DRAGGING A WEAK...BUT DRY...COLD FRONT THROUGH HERE LATE IN THE DAY ON THURSDAY. HIGH PRESSURE BUILDS BACK IN FOR FRIDAY. SATURDAY...FORECAST CONFIDENCE IS LOW TO MEDIUM. THE GFS AND THE ECMWF ARE PERSISTENT AND CONSISTENT ON DEVELOPING A VERY LARGE LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS ON SATURDAY. THE SURGE OF WARMER AIR AND MOISTURE INTO THE REGION SHOULD LEAD TO RAIN SPREADING ACROSS THE UPPER MIDWEST INTO THE WESTERN GREAT LAKES DURING THE DAY ON SATURDAY...CONTINUING THROUGH SATURDAY NIGHT. IT LOOKS LIKE A WET WEEKEND AT THIS POINT. AVIATION/00Z TAFS/... VFR CONDITIONS EXPECTED THROUGH SUNDAY ACROSS TAF SITES. GUSTY NORTHWEST WINDS SHOULD SUBSIDE BY SUNSET...WITH LIGHT NORTHWEST WINDS OVERNIGHT AS HIGH PRESSURE PASSES WELL SOUTHWEST OF THE REGION. EXPECT BROKEN TO OVERCAST CLOUDS TO LINGER THROUGH EARLY TO MID EVENING...BEFORE GRADUALLY MIXING OUT LATE THIS EVENING AND OVERNIGHT. LIGHT WEST WINDS IN THE MORNING WILL SHIFT SOUTHWEST SUNDAY AFTERNOON...UNDER MOSTLY SUNNY SKIES. MARINE... A TIGHT PRESSURE GRADIENT WILL DEVELOP ACROSS THE REGION LATE SUNDAY NIGHT AND LINGER INTO MONDAY NIGHT/TUESDAY MORNING...BEFORE A COLD FRONT MOVES THROUGH THE AREA. SOUTHWEST WINDS WILL BECOME GUSTY DURING THIS TIME. SOME GUSTS WILL APPROACH GALE FORCE AT TIMES. HIGH WAVES WILL BE LIMITED TOWARD THE OPEN WATERS...GIVEN THE OFFSHORE FLOW. A SMALL CRAFT ADVISORY OR GALE WATCH MAY BE NEEDED FOR THIS PERIOD IN LATER FORECASTS. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT SUNDAY FOR WIZ046-047-051- 052-056>060-062>072. LM...NONE. && $$ UPDATE...HENTZ TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD SUNDAY NIGHT THROUGH SATURDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
632 PM CDT SAT OCT 6 2012 .SHORT TERM...TONIGHT THROUGH TUESDAY 252 PM CDT SAT OCT 6 2012 MAIN FORECAST CONCERNS ARE ON FREEZE POTENTIAL TONIGHT...NEAR CRITICAL FIRE WEATHER CONDITIONS SUNDAY AND MONDAY...AND FINALLY PRECIPITATION CHANCES FOR MONDAY NIGHT AND TUESDAY. CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER THE NORTHEAST PACIFIC AND ALONG THE WEST COAST OF THE U.S....WHILE DEEP TROUGHING WAS PRESENT OVER CENTRAL AND EASTERN CANADA SOUTHWARD INTO THE CENTRAL PLAINS AND OHIO RIVER VALLEY. WITHIN THE TROUGHING...A SHORTWAVE TROUGH EXTENDED EAST-WEST ACROSS THE FORECAST AREA AND WEST TOWARDS NEBRASKA. UNDERNEATH THIS SHORTWAVE TROUGH WAS AN AREA OF BROKEN STRATUS ACROSS THE FORECAST AREA TO NEAR DULUTH. MUCH OF THIS STRATUS WAS SITUATED AT 750MB OR BELOW PER 12Z SOUNDINGS FROM INL...MPX AND GRB. THE REASON THE DECK IS NOT A SOLID OVERCAST IS THAT THE SOUNDINGS DO NOT SHOW COMPLETE SATURATION. IN FACT...SOME OF THE STRATUS FORMATION HAS BEEN DUE TO DAYTIME HEATING...NOTED BY HOLES THAT FILLED IN DURING THE MORNING. FARTHER TO THE NORTHWEST ON WATER VAPOR...A SHORTWAVE TROUGH WAS EVIDENT IN SOUTHERN SASKATCHEWAN DROPPING DOWN THE EAST SIDE OF THE NORTHEAST PACIFIC RIDGE. LACK OF LOW LEVEL MOISTURE SEEN ON THE 12Z THE PAS MANITOBA SOUNDING HAS RESULTED IN THE SHORTWAVE JUST PRODUCING A BAND OF MID AND HIGH CLOUDS. AT THE SURFACE...HIGH PRESSURE WAS SITUATED OVER THE CENTRAL PLAINS WITH A RIDGE AXIS EXTENDING NORTHEAST INTO NORTHERN MINNESOTA. 850MB TEMPS CHILLY OVER THE FORECAST AREA...BETWEEN -5 AND -7C PER 12Z RAOBS...OR 2 STANDARD DEVIATIONS BELOW NORMAL. TONIGHT AND SUNDAY...SHORTWAVE TROUGH OVER SOUTHERN SASKATCHEWAN IS PROGGED TO KEEP DROPPING SOUTHEAST THROUGH THE DEEP UPPER TROUGH... CROSSING THE FORECAST AREA SUNDAY AFTERNOON. THIS TROUGH WILL DO A COUPLE OF THINGS. FIRST...THE SURFACE RIDGE AXIS OVER MINNESOTA WILL GET PUSHED DOWN OVER THE FORECAST AREA TONIGHT. AS THE RIDGE AXIS AND THE DRY AIR ASSOCIATED WITH IT MOVE IN...SKIES WILL CLEAR. WINDS SHOULD DECOUPLE AS WELL...EXCLUDING THE HIGHER TERRAIN OF SOUTHEAST MINNESOTA. GIVEN THE COOL DAY TODAY...THE SETUP CERTAINLY FAVORS LOWS DROPPING INTO THE 20S AS HAS BEEN FORECAST THE PAST FEW DAYS. SOME OF THE TYPICAL COLD SPOTS IN WISCONSIN COULD EVEN HIT THE UPPER TEENS. FREEZE WARNINGS THEREFORE STILL LOOK GOOD WITH THIS LIKELY BEING THE END OF THE GROWING SEASON. THE SECOND THING THE SHORTWAVE TROUGH WILL DO IS TO SPREAD THE CIRRUS AND SOME MID CLOUDS SEEN UP IN SOUTH CENTRAL CANADA ACROSS THE FORECAST AREA. REGARDING TEMPERATURES... DOWNSLOPING OF AIR OFF THE ROCKIES AHEAD OF THE SHORTWAVE TROUGH WILL ALLOW A PLUME OF WARMER 925-850MB AIR TO ADVECT INTO THE FORECAST AREA. BY 18Z... 925MB AND 850MB TEMPS RISE TO 2-4C AND -3 TO -5C RESPECTIVELY. COMBINE THESE WITH AN INCREASING SOUTHWEST WIND AS THE SURFACE RIDGE DROPS SOUTH AND HIGHS SHOULD BE ABLE TO REACH INTO THE LOW TO MID 50S. DRY DEWPOINTS IN THE TEENS WILL HELP RELATIVE HUMIDITIES PLUMMET INTO THE 20-30 PERCENT RANGE...RAISING SOME FIRE WEATHER CONCERNS. THESE ARE NOTED IN THE FIRE WEATHER DISCUSSION BELOW. SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO A SHORTWAVE CURRENTLY WELL UP TO THE NORTHWEST...NEAR THE NORTHWEST CORNER OF THE NORTHWEST TERRITORIES. MODELS HAVE BEEN VERY CONSISTENT OF DROPPING THIS SHORTWAVE INTO THE DEEP TROUGH...REACHING SOUTHERN PORTIONS OF SASKATCHEWAN AND MANITOBA BY 12Z MONDAY. AS THE SHORTWAVE DROPS SOUTH...A DEEPENING SURFACE LOW ACCOMPANIES IT...WHICH SHOULD REACH FAR SOUTHERN MANITOBA BY 12Z MONDAY. THIS DEEPENING LOW WILL HELP TO INCREASE THE SOUTHWEST WINDS EVEN MORE OVER THE FORECAST AREA...AND ALSO ENHANCE THE DOWNSLOPE EFFECT OFF THE ROCKIES. AS SUCH...925 AND 850MB TEMPS CLIMB TO 6C AND 4C RESPECTIVELY AT 12Z MONDAY. THIS WARM ADVECTION IS LIKELY TO RESULT AN INCREASE OF MID AND HIGH CLOUDS... ESPECIALLY AFTER MIDNIGHT SUNDAY NIGHT AND HEADING INTO THE DAY MONDAY. THESE CLOUDS COMBINED WITH THE WINDS WILL HELP PRODUCE A MUCH WARMER NIGHT...ALBEIT STILL BELOW NORMAL...MAINLY IN THE 30S. AFTER 12Z MONDAY...MODELS DIFFER A BIT ON THE TRACK...DEPTH AND SPEED OF THE SHORTWAVE TROUGH AND SURFACE LOW. OVERALL...THOUGH... THE GENERAL THEME IS FOR THE SHORTWAVE AND SURFACE LOW TO HEAD EAST...LIKELY ALONG THE ONTARIO/MN BORDER. COLD FRONT ASSOCIATED WITH THE LOW STAYS TO OUR WEST...ONLY REACHING ALBERTA LEA BY 00Z. 925MB AND 850MB TEMPS CONTINUE TO WARM AHEAD OF THIS FRONT...TOPPING OUT AT 12-14C AND 6-8C RESPECTIVELY. WITH A TIGHT PRESSURE GRADIENT AND MIXING RESULTING IN BREEZY SOUTHWEST WINDS...ALONG WITH DRY LOW LEVEL AIR...WE SHOULD BE ABLE TO MIX TO NEAR 850MB. ONLY CAVEAT IS THE MID/HIGH CLOUDS...WHICH LOOK TO INCREASE AND THICKEN THROUGH THE DAY. ANY PRECIPITATION WITH THESE CLOUDS SHOULD STAY NORTH OF THE FORECAST AREA PER MODEL CONSENSUS. HIGHS IN THE 60S STILL ARE REASONABLE...PERHAPS GETTING CLOSE TO 70 WEST OF THE MISSISSIPPI RIVER. FIRE WEATHER CONCERNS EXIST AGAIN WITH THE BREEZY SOUTHWEST WINDS...TEMPERATURES AND LOW RELATIVE HUMIDITIES. SEE FIRE WEATHER DISCUSSION BELOW. MONDAY NIGHT AND TUESDAY...MODELS SHOW YET ANOTHER FAIRLY STRONG SHORTWAVE DROPPING DOWN THE EAST SIDE OF THE NORTHEAST PACIFIC RIDGE...DIGGING INTO NORTH DAKOTA BY 12Z TUESDAY AND THEN INTO SOUTHERN MINNESOTA BY 00Z WEDNESDAY. THIS SHORTWAVE SHOULD HELP TO ENHANCE LIFT IN THE WAKE OF THE COLD FRONT...ON TOP OF THE POST-FRONTAL MID LEVEL FRONTOGENESIS THAT WILL ALREADY EXIST. SO ONCE THE COLD FRONT MOVES EAST THROUGH THE FORECAST AREA...WHICH GRADUALLY OCCURS DURING THIS PERIOD UNTIL THIS SHORTWAVE CAN CATCH UP...ANTICIPATE A BAND OF RAIN TO DEVELOP. THIS SIGNAL OF THE BAND OF RAIN CONTINUES TO GET STRONGER...WITH THE 06.12Z GFS...NAM... UKMET...CANADIAN AND ECMWF ALL DEPICTING IT. AS SUCH...HAVE RAISED PRECIPITATION CHANCES UP TO AROUND 40. FURTHER INCREASES WILL LIKELY BE NEEDED IF THIS SIGNAL PERSISTS. PRECIPITABLE WATER VALUES ARE ONLY AROUND 0.75 OF AN INCH...SO MOISTURE IS NOT THAT GREAT...BUT THE FORCING SHOULD BE ABLE TO SQUEEZE OUT SOME LIGHT PRECIPITATION. WITH PLENTY OF CLOUDS MONDAY NIGHT AND THE SLOW COLD FRONTAL PASSAGE...LOWS IN THE 40S SUGGESTED BY MAV/MET GUIDANCE SEEM REASONABLE. 850MB TEMPS DO GRADUALLY FALL DURING THE DAY TUESDAY...BOTTOMING OUT AROUND 0C BY 00Z. NEVERTHELESS...HIGHS SHOULD BE ABLE TO TOP OUT IN THE 50S...COOLEST IN THE NORTHWEST WHICH ENDS UP MOSTLY BEHIND THE FRONT FOR THE ENTIRE DAY. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 252 PM CDT SAT OCT 6 2012 GOOD MODEL AGREEMENT EXISTS BETWEEN THE 06.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ABOUT A PATTERN SHIFT OCCURRING DURING THE LONG TERM FORECAST...WITH THE CURRENT DEEP TROUGH LIFTING OUT ON FRIDAY. WE STILL HAVE ONE MORE POTENT SHORTWAVE TO DEAL WITH DROPPING THE TROUGH PRIOR TO LIFT-OUT...PROGGED TO CROSS LAKE SUPERIOR LATE THURSDAY. AFTER FRIDAY...MODELS SHOW AN UPPER LOW...CURRENTLY JUST OFF THE COAST OF CALIFORNIA...LIFTING OUT OF THE SOUTHWESTERN U.S.. EXACTLY HOW FAST THIS EJECTION OCCURS THE MODELS ARE ALL OVER THE PLACE...WITH THE LATEST 06.12Z GFS THE FASTEST AMONGST ALL MODELS AND PAST 1-2 DAYS OF RUNS OF THE MODEL. THE GFS HAS THIS DEEP LOW LIFTING UP INTO SOUTHERN MINNESOTA BY 00Z SUNDAY. EJECTING UPPER LOWS OUT OF THE SOUTHWESTERN U.S. ARE ALWAYS PROBLEMATIC FOR MODELS...SINCE THEY HINGE ON UPPER TROUGHS CROSSING THE PACIFIC. THEREFORE...HAVE LOW CONFIDENCE ON ANY SOLUTION AT THIS POINT... THOUGH IT WOULD NOT BE SURPRISING IF A SLOWER IDEA ENDS UP PANNING OUT PER MODEL BIASES. IN THE WAKE OF TUESDAYS SHORTWAVE...A RIDGE OF HIGH PRESSURE IS FORECAST TO BUILD IN FOR WEDNESDAY. ANOTHER SHOT OF COOL AIR COMES WITH THIS RIDGE WITH 850MB TEMPS FALLING TO AROUND -4C. THUS... TUESDAY NIGHT AND WEDNESDAY WILL BE COOL...BUT NOT NEARLY AS COLD AS TODAY OR TONIGHT. COULD BE SOME LINGERING PRECIP TUESDAY EVENING IN THE SOUTHEASTERN THIRD OF THE AREA...ASSOCIATED WITH TUESDAYS SHORTWAVE...OTHERWISE EXPECT DRY CONDITIONS. WITH THE THURSDAY SHORTWAVE DROPPING DOWN INTO LAKE SUPERIOR...WE GET ANOTHER COLD FRONT TO MOVE THROUGH THE FORECAST AREA. DUE TO LIMITED SPACING BETWEEN THE CANADIAN RIDGE OF HIGH PRESSURE AND THIS FRONT...NOT ANTICIPATING ANY POST-FRONTAL PRECIPITATION. AHEAD OF THE FRONT...A SURGE OF 4-6C 850MB AIR IS PROGGED TO COME INTO THE AREA ON STRONG SOUTHWEST WINDS. SO WE COULD HAVE ANOTHER NEAR CRITICAL FIRE WEATHER DAY...PARTICULARLY SOUTH OF I-90. ANOTHER COOLER HIGH PRESSURE AREA IS SLATED TO DROP DOWN INTO OUR REGION FOR FRIDAY...WITH 850MB TEMPS DROPPING BACK TO AROUND -4C AT 12Z. FOR FRIDAY NIGHT AND SATURDAY... HAVE FOLLOWED THE CONSENSUS APPROACH AND SPREADING CHANCES OF PRECIPITATION INTO THE AREA FROM THE SOUTHWEST. THESE ARE ALL DUE TO WARM...MOIST AIR ADVECTION OUT OF THE GULF OF MEXICO COMING INTO THE COLDER AIRMASS SITUATED OVER THE FORECAST AREA. MORE REFINEMENT OF THESE CHANCES WILL COME DURING THE NEXT SEVERAL DAYS AS TIMING OF THE UPPER LOW EJECTION BECOMES MORE CERTAIN. SHOULD SEE A GRADUAL WARM UP IN TEMPERATURES TOO WITH THE WARMER AIR ADVECTING INTO THE AREA. HIGHS BY SATURDAY STILL LOOK BELOW NORMAL BUT ONLY 5 OR SO DEGREES...NOT LIKE THE 15-20 AS OF LATE. && .AVIATION...TONIGHT AND SUNDAY 632 PM CDT SAT OCT 6 2012 SURFACE HIGH PRESSURE WILL BUILD EASTWARD INTO THE AREA OVERNIGHT TONIGHT. EXPECT THE VFR CEILINGS TO BREAK UP OVER THE TAF SITES THROUGH THE EVENING HOURS AS DRIER AIR ADVECTS INTO THE REGION FROM THE NORTHWEST. WINDS WILL ALSO CONTINUE DIMINISH AS THE GRADIENT RELAXES. EXPECT THE VFR CONDITIONS TO PREVAIL THROUGH THE REMAINDER OF THE TAF PERIOD WITH JUST SOME HIGH CLOUDS SUNDAY AFTERNOON. && .FIRE WEATHER...SUNDAY INTO MONDAY 252 PM CDT SAT OCT 6 2012 NEAR CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE BOTH SUNDAY AND MONDAY. SETTING THE STAGE FOR THESE CONDITIONS IS THE MODERATE TO EXTREME DROUGHT CONDITIONS IN PLACE ACROSS THE AREA...ALONG WITH A KILLING FREEZE EXPECTED TONIGHT. FOR SUNDAY...SOUTHWEST WINDS ARE EXPECTED TO INCREASE IN THE WAKE OF A RIDGE OF HIGH PRESSURE DROPPING SOUTH ACROSS THE AREA TONIGHT. THESE WINDS SHOULD BE SUSTAINED IN THE 10-15 MPH RANGE WITH GUSTS OF 12-22 MPH...STRONGEST ACROSS SOUTHEAST MINNESOTA. DEWPOINTS ARE LIKELY TO STILL BE LOW...THANKS TO MIXING OF DRY AIR ALOFT AND THE RECENT COLD NIGHT. HOWEVER...LINGERING COLD AIR THAT ONLY SLOWLY MODIFIES WILL ONLY ALLOW HIGH TEMPERATURES TO TOP OUT IN THE LOW TO MID 50S. THESE TEMPERATURES COMBINED WITH THE DEWPOINTS SHOULD PRODUCE MINIMUM RELATIVE HUMIDITIES IN THE 20-30 PERCENT RANGE... LOWEST SOUTH AND WEST OF I-94. THEREFORE...THE MAIN LIMITING FACTORS FOR RED FLAG CONDITIONS WOULD BE THE TEMPERATURES AND WINDS. FOR MONDAY...A STRENGTHENING LOW PRESSURE SYSTEM DROPPING SOUTH OUT OF CENTRAL CANADA INTO NORTHERN MINNESOTA WILL RESULT IN A TIGHTER PRESSURE GRADIENT ACROSS THE AREA. AS SUCH...STRONGER WINDS ARE ANTICIPATED...IN THE 15-25 MPH RANGE WITH GUSTS OF 20-35 MPH. HIGHEST WINDS ARE LIKELY WEST OF THE MISSISSIPPI RIVER. THESE WINDS SHOULD BRING UP A LITTLE MORE MOISTURE...BUT HIGH TEMPERATURES WILL MOSTLY COUNTERACT IT BY JUMPING INTO THE 60S. THEREFORE...MINIMUM RELATIVE HUMIDITIES ARE ONLY SLIGHTLY HIGHER...BETWEEN 25-35 PERCENT...LOWEST ALONG/WEST OF THE MISSISSIPPI RIVER. GIVEN THE SLIGHTLY HIGHER MINIMUM RELATIVE HUMIDITIES...TEMPERATURES STILL SLIGHTLY COOL AND ESPECIALLY POTENTIAL FOR A LOT OF CLOUDS... CONDITIONS AGAIN JUST LOOK NEAR CRITICAL. THE CLOUDS COULD BE QUITE PROBLEMATIC BY KEEPING RELATIVE HUMIDITIES HIGHER THAN EXPECTED. PER COORDINATION WITH AREA FIRE WEATHER AGENCIES...HAVE HELD OFF ON ANY FIRE WEATHER WATCHES AT THIS TIME. LOOKING AHEAD...ANOTHER NEAR CRITICAL FIRE WEATHER DAY COULD OCCUR SOUTH OF I-90 ON THURSDAY...AHEAD OF A CANADIAN COLD FRONT. && .ARX WATCHES/WARNINGS/ADVISORIES... 252 PM CDT SAT OCT 6 2012 WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT SUNDAY FOR WIZ032-033-041- 053>055-061. MN...FREEZE WARNING FROM 1 AM TO 8 AM CDT SUNDAY FOR MNZ079-088-096. IA...FREEZE WARNING FROM 1 AM TO 8 AM CDT SUNDAY FOR IAZ011-030. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...RABERDING FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1154 PM CDT THU OCT 4 2012 .SHORT TERM...TONIGHT THROUGH SUNDAY 257 PM CDT THU OCT 4 2012 MAIN FORECAST CONCERNS ON BREEZY NORTHWEST WINDS THIS EVENING AND AGAIN ON FRIDAY. FOCUS THEN TURNS TO LOW PRECIPITATION CHANCES ON SATURDAY AND TEMPERATURES THROUGH THE WEEKEND. LATEST WATER VAPOR IMAGERY SHOWED A POTENT LOW PRESSURE SYSTEM OVER NORTHERN MINNESOTA RESPONSIBLE FOR PRODUCING HEAVY...WET SNOW OVER PORTIONS OF NORTHWEST MINNESOTA. SURFACE OBSERVATIONS INDICATED A TIGHT PRESSURE GRADIENT OVER THE FORECAST AREA IN THE WAKE OF A COLD FRONT THAT MOVED THROUGH THIS MORNING. THE TIGHT GRADIENT AND COLD AIR ADVECTION BEHIND THE FRONT WAS KEEPING BREEZY WEST/NORTHWEST ACROSS THE FORECAST AREA. THE LOW IS EXPECTED TO LIFT NORTHEAST TONIGHT INTO SOUTHWEST ONTARIO AND MEANDER EAST...JUST NORTH OF LAKE SUPERIOR. A TIGHT PRESSURE GRADIENT WILL REMAIN IN PLACE OVER THE AREA AS THE REGION IS IN BETWEEN THE LOW PASSING TO THE NORTH AND HIGH PRESSURE ATTEMPTING TO BUILD INTO THE DAKOTAS. THIS WILL KEEP BREEZY CONDITIONS THROUGH THIS EVENING. WINDS WILL TAPER OFF LATE IN THE EVENING FOR LOCATIONS ALONG AND SOUTH OF INTERSTATE 90. NAM AND RUC LOW LEVEL RELATIVE HUMIDITY FIELDS SHOWS A SCATTERED TO BROKEN STRATUS DECK MOVING IN FROM THE NORTHWEST THIS EVENING AND MAKING IT TO ABOUT THE INTERSTATE 90 CORRIDOR. HAVE INCREASED CLOUD COVER THIS EVENING INTO THE OVERNIGHT HOURS ACROSS THESES AREAS. LOOK FOR LOW TEMPERATURES TO FALL INTO THE 30S TONIGHT. AN UPPER TROUGH WILL DIVE SOUTH INTO THE DAKOTAS AND NORTHERN MINNESOTA ON FRIDAY OUT OF SOUTHERN MANITOBA...SASKATCHEWAN AND ALBERTA AS THE LOW FILLS AND LIFTS NORTHEAST OVER JAMES BAY. PLAN ON CONTINUED BREEZY NORTHWEST WINDS ACROSS THE AREA ON FRIDAY AS THE PRESSURE GRADIENT REMAINS TIGHT. WIND SPEEDS ARE EXPECTED TO RANGE FROM 14 TO 24 MPH. SOME GUSTS IN THE 25 TO 30 MPH RANGE ARE POSSIBLE IN OPEN AREAS. THE GRADIENT WILL REMAIN TIGHTER THOUGH THE DAY ACROSS CENTRAL INTO NORTH CENTRAL WISCONSIN SO HAVE INCREASED WINDS GUSTS SLIGHTLY ACROSS THESE AREAS. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 40S ACROSS NORTHERN WISCONSIN TO THE LOWER 50S OVER NORTHEAST IOWA. THE TROUGH IS EXPECTED TO PUSH SOUTH INTO CENTRAL MINNESOTA AND NORTHERN WISCONSIN LATE FRIDAY NIGHT INTO SATURDAY MORNING. CLOUDS WILL BE ON THE INCREASE FROM NORTH TO SOUTH AS THE TROUGH MOVES IN. CANNOT RULE OUT A LIGHT SPRINKLE OR SNOW SHOWER FRIDAY NIGHT INTO SATURDAY MORNING ALONG AND NORTH OF THE INTERSTATE 94 CORRIDOR. FORECAST SOUNDING ARE NOT SHOWING ENOUGH SATURATION FOR ICE ALOFT SO THE PRECIPITATION COULD FALL AS SPRINKLES OR POSSIBLY FREEZING SPRINKLES DEPENDING ON SURFACE TEMPERATURES. THERE APPEARS TO BE ENOUGH SATURATION FOR PRECIPITATION BUT THERE REALLY IS NOT APPRECIABLE LIFT SO CONCERNED THAT THE MAIN IMPACT FROM THE TROUGH WILL BE JUST INCREASING STRATUS AND NO PRECIPITATION. WILL MAINTAIN SLIGHT CHANCES FOR RAIN/SNOW SHOWERS OVER NORTH CENTRAL WISCONSIN. PLAN ON LOW TEMPERATURES RANGING FROM THE UPPER 20S TO LOWER 30S OVER NORTH CENTRAL WISCONSIN TO THE LOWER 30S OVER NORTHEAST IOWA. GUIDANCE HAS BEEN TRENDING COOLER FRIDAY NIGHT BUT CONCERNED THAT THE INCREASING CLOUD COVER AND PERSISTENT NORTHWEST WINDS WILL LEAD TO SLIGHTLY WARMER TEMPERATURES. WILL HAVE TO KEEP A CLOSE WATCH ON THE PROGRESSION OF THE STRATUS DECK FRIDAY NIGHT AND WINDS. LOCATIONS THAT REMAIN CLEAR AND DECOUPLE COULD SEE TEMPERATURES PLUMMET INTO THE MID 20S. SATURDAY WILL BE A RATHER CHILLY FALL DAY ACROSS THE REGION. THE TROUGH WILL CONTINUE ITS SOUTHWARD PUSH...LEADING TO AN EXPANSIVE STRATUS DECK ACROSS MUCH OF THE FORECAST AREA. DECIDED TO MAINTAIN A SLIGHT CHANCE FOR RAIN/SNOW SHOWERS OVER NORTH CENTRAL WISCONSIN AS THE TROUGH MOVES THROUGH DURING THE MORNING HOURS. HAVE INCLUDED A CHANCE OF FLURRIES ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY SATURDAY MORNING...THEN SWITCHED OVER TO SPRINKLES LATE IN THE MORNING AS TEMPERATURES WARM. SEEING THE SATURATION FOR SOME PRECIPITATION IN THE FORECAST SOUNDINGS BUT VERY MINIMAL LIFT. THINKING THE TROUGH SHOULD BE ABLE TO PRODUCE SOME VERY LIGHT PRECIP AS IT MOVES THROUGH. OTHERWISE...PLAN ON A MOSTLY CLOUDY AND COOL DAY WITH HIGHS RANGING FROM THE LOWER 40S OVER NORTHERN WISCONSIN TO THE UPPER 40S ACROSS NORTHEAST IOWA. SATURDAY INTO SATURDAY NIGHT...850 MB TEMPERATURE STANDARDIZED ANOMALIES WILL FALL TO AROUND -1.5 C BASED ON THE ECMWF....WHILE THE NAM IS SUGGESTING -2.0 C. ANOMALIES THIS LOW SUGGEST THE POTENTIAL FOR NEAR RECORD LOW TEMPERATURES ACROSS THE REGION. THE COLD AIRMASS OVER THE REGION AND CLEARING SKIES LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING WILL LEAD TO NEAR RECORD LOW TEMPERATURES AND A HARD...GROWING SEASON ENDING FREEZE...WITH LOWS FALLING INTO THE 20S. A FREEZE WARNING WILL BE NEEDED LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING. SURFACE HIGH PRESSURE WILL EDGE INTO THE REGION ON SUNDAY WITH MOSTLY SUNNY SKIES EXPECTED. AFTER A COLD START TO THE DAY...LOOK FOR HIGH TEMPERATURES TO REBOUND INTO THE UPPER 40S OVER NORTHERN WISCONSIN TO THE LOWER 50S ACROSS NORTHEAST IOWA. .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY 257 PM CDT THU OCT 4 2012 04.12 MEDIUM RANGE MODELS IN REASONABLE AGREEMENT THROUGH THE EXTENDED PERIOD. NORTHWEST FLOW ALOFT WILL CONTINUE INTO SUNDAY NIGHT WITH SURFACE HIGH PRESSURE IN CONTROL. THE HIGH IS EXPECTED TO SLIDE EAST OF THE AREA MONDAY AS A COLD FRONT DRIFTS SOUTH ACROSS NORTHERN MINNESOTA INTO SOUTHERN NORTH DAKOTA. MEANWHILE...AN UPPER TROUGH WILL MOVE THROUGH MONTANA AND INTO WESTERN NORTH DAKOTA. SOUTHWEST FLOW AHEAD OF THE APPROACHING FRONT WILL HELP TEMPERATURES CLIMB INTO THE UPPER 50S TO LOWER 60S ACROSS THE FORECAST AREA MONDAY AFTERNOON. THE FRONT IS EXPECTED TO PUSH SOUTH INTO NORTHERN WISCONSIN LATE MONDAY NIGHT BRINGING A SLIGHT CHANCE OF RAIN SHOWERS TO NORTH CENTRAL WISCONSIN. THE FRONT WILL CONTINUE TO MOVE SOUTH DURING THE DAY ON TUESDAY BRINGING A SLIGHT CHANCE OF RAIN SHOWERS TO MUCH OF THE FORECAST AREA. HIGH PRESSURE IS EXPECTED TO BUILD BACK INTO THE UPPER MISSISSIPPI RIVER VALLEY WEDNESDAY INTO THURSDAY PROVIDING DRY AND QUIET WEATHER. LOOK FOR HIGH TEMPERATURES IN THE 50S ON WEDNESDAY...CLIMBING INTO THE MID 50S TO LOWER 60S THURSDAY AFTERNOON. && .AVIATION...THROUGH 06Z SATURDAY 1154 PM CDT THU OCT 4 2012 THE VFR STRATUS DECK NORTH OF THE TAF SITES EARLIER THIS EVENING DID MAKE IT INTO THE TAF SITES LATE THIS EVENING. WESTERLY WINDS CONTINUE TO GUST UPWARDS OF 20 TO 25 KNOTS AT BOTH SITES. EXPECT CEILINGS OF 035K-040K FOOT TO PERSIST THROUGH THE OVERNIGHT HOURS. LATEST SATELLITE TRENDS DOES SHOW SOME ERODING OF THE CLOUDS ALONG THE SOUTHERN FLANK...SO TAF SITES MAY REMAIN ON THE EDGE. WINDS WILL REMAIN STRONG OVERNIGHT WITH SOME GUSTS CONTINUING IN THE 20 TO 25 KNOT RANGE. STRATUS SHOULD MIX OUT FRIDAY AFTER 15Z WITH PRESSURE GRADIENT REMAINING TIGHT AND WINDS CONTINUING TO GUST UPWARDS OF 25 KNOTS. ANOTHER SURFACE TROUGH DROPS SOUTHWARD THROUGH NORTHERN MINNESOTA AFTER 00Z SATURDAY. NAM IS SHOWING A SOUTHWARD PUSH OF 850MB-925MB MOISTURE TOWARDS THE TAF SITES. TIMING AT THIS TIME LOOKS TO BE AROUND OR JUST AFTER 06Z...SO WILL JUST KEEP MENTION OF A SCATTERED DECK AT THIS TIME....BUT WILL LIKELY SEE SOME CEILINGS DEVELOP AFTER 06Z IN THE UPPER MVFR LOWER VFR CATEGORY. && .ARX WATCHES/WARNINGS/ADVISORIES... 257 PM CDT THU OCT 4 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DENVER CO
333 AM MDT SUN OCT 7 2012 .SHORT TERM...NNW FLOW ALOFT WILL BE OVER THE AREA THRU TONIGHT WITH DRY CONDITIONS EXPECTED. MAIN CONCERN FOR THIS MORNING WILL BE FOG POTENTIAL OVER NERN CO. SO FAR THE ONLY PALCE WITH FOG IS OVER THE FAR NERN CORNER WHERE SKIES HAVE BEEN CLEAR OVERNIGHT. CLOSER TO THE FRONT RANGE LOW LVL CLOUDS HAVE REMAINED IN PLACE BUT HAVE BEEN SLOWLY DIMINISHING THE LAST FEW HOURS. AT THIS TIME WILL KEEP AREAS OF FOG OVER THE PLAINS WHERE SKIES HAVE BEEN GENERALLY CLEAR AND ONLY MENTION PATCHY FOG CLOSER TO THE FOOTHILLS. AS FAS AS AFTN HIGHS WILL KEEP HIGHS IN THE LOWER TO MID 50S ACROSS NERN CO FOR THIS AFTN. FOR TONIGHT SHOULD SEE MAINLY CLEAR SKIES. MAY SEE SOME GUSTY WINDS IN THE MTNS AND HIGHER FOOTHILLS LATE TONIGHT AS A WK MTN WAVE DEVELOPS. .LONG TERM...NORTHERN COLORADO WILL BE UNDER A MODERATE NORTHWEST FLOW PATTERN THROUGH MIDWEEK WITH A DRY AIRMASS IN PLACE. THERE WILL BE A WEAK TROF WHICH MOVES THROUGH THE NORTHERN PLAINS STATES ON TUESDAY. THERE WILL BE AN ASSOCIATED COLD FRONT WHICH WILL COOL TEMPERATURES ACROSS NORTHEAST COLORADO ON TUESDAY AS LOW LEVEL INVERSIONS REMAIN IN PLACE. LATEST NAM BRINGS IN SOME LOW LEVEL MOISTURE AND POTENTIAL STRATUS OVER THE PLAINS WHILE THE GFS AND EUROPEAN ARE DRY. APPEARS MOST OF THE MOISTURE WITH THIS SYSTEM WILL BE TOO FAR NORTH AND EAST OF COLORADO FOR ANY BENEFIT. WARMER AGAIN ON WEDNESDAY AS HEIGHTS BUILD AS TEMPERATURES RETURN CLOSE TO CLIMATE NORMALS FOR THIS TIME OF YEAR. THE NEXT WEATHER MAKER WILL BE CLOSED LOW WHICH WILL BE OFF THE SOUTHERN CALIFORNIA COAST BY THURSDAY WHICH WILL RESULT IN SOME DOWNSTREAM RIDGING ACROSS COLORADO. THE FLOW ALOFT WILL SHIFT WEST TO SOUTHWEST THURSDAY AND FRIDAY AS MOISTURE VALUES SLOWLY ELEVATE. THE LOW IS PROGGED TO EJECT INTO COLORADO SOMETIME IN THE FRIDAY THROUGH SATURDAY TIME FRAME DEPENDING ON WHICH MODEL. SOLUTIONS VARY FROM THE SLOWER GFS SOLUTION TO THE FASTEST EUROPEAN. SEEMS LIKE THERE IS EVEN MORE VARIATION IN THE SOLUTIONS TODAY COMPARED TO YESTERDAY SO FORECAST CONFIDENCE NOT VERY HIGH. TYPICALLY THESE SYSTEMS END UP BEING SLOWER THAN FORECAST. NO MAJOR CHANGES PLANNED IN UPCOMING FORECAST PACKAGE FOR THE LONG TERM AND WILL KEEP LOW POPS FOR THE ENTIRE AREA ON FRIDAY AND SATURDAY. && .AVIATION...SO FAR THE HRRR AND THE RAP ARE NOT REAL EXCITED ABOUT LIFR CONDITIONS IN THE 10Z-15Z TIME PERIOD AS BOTH KEEP LIFR CONDITIONS TO THE NE OF THE AIRPORT. RAP STILL SHOWS A WEAK DENVER CYCONE NR THE AIRPORT BY 12Z SO AM TEMPTED TO LEAVE IN A BRIEF 3 HR WINDOW FM 12Z-15Z FOR SOME LOWER CEILINGS AND FOG FOR NOW AS SKIES HAVE STARTED TO CLEAR. FOR THIS AFTN AND TONIGHT EXPECT VFR CONDITIONS. WINDS WILL BE LIGHT AND VARIABLE THIS MORNING AND THEN BECOME LIGHT NLY BY AFTN. FOR TONIGHT WINBDS SHOULD BECOME DRAINAGE. && .BOU WATCHES/WARNINGS/ADVISORIES... HARD FREEZE WARNING UNTIL 9 AM MDT THIS MORNING FOR COZ038>051. && $$ SHORT TERM...RPK LONG TERM....ENTREKIN AVIATION...RPK
AREA FORECAST DISCUSSION
NWS ALBANY NY
136 AM EDT SUN OCT 7 2012 .SYNOPSIS... MUCH COOLER AIR WILL CONTINUE TO STREAM INTO OUR REGION OVERNIGHT AS WEAK HIGH PRESSURE CRESTS ACROSS THE REGION. LOW PRESSURE WILL MOVE ALONG A FRONTAL BOUNDARY STALLED JUST TO OUR SOUTH GIVING US MORE UNSETTLED WEATHER FOR SUNDAY AFTERNOON INTO SUNDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION ON MONDAY AND BRING FAIR AND SEASONABLE WEATHER FOR THE FIRST HALF OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1 AM EDT...A BAND OF LAKE EFFECT RAIN SHOWERS HAS DEVELOPED OFF LAKE ONTARIO. WHILE THE MAJORITY OF THESE RAIN SHOWERS ARE REMAINING CLOSE TO THE LAKESHORE AND ACROSS THE TUG HILL...A FEW SHOWERS WILL MAKE IT INTO THE FAR WESTERN ADIRONDACKS. AS THE FLOW SHIFTS...THIS BAND WILL GRADUALLY SHIFT SOUTH...POSSIBLY AFFECTING PARTS OF THE WESTERN MOHAWK VALLEY BY LATE TONIGHT. THIS IS BEING MODELED WELL BY THE LATEST HRRR AND LOCAL WRF. MEANWHILE...A SFC FRONTAL BOUNDARY CONTINUES TO MOVE TO THE SOUTH AND EAST OF OUR AREA ACROSS EASTERN NEW ENGLAND AND DOWN OFF THE MID ATLANTIC SEABOARD. MID AND HIGH LEVEL CLOUDS ARE ALREADY BEGINNING TO STREAK INTO THE REGION FROM THE SOUTHWEST...AND WILL CONTINUE TO INCREASE TOWARD DAYBREAK AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONTAL BOUNDARY TO OUR SOUTH. MIN TEMPS OVERNIGHT WILL BE MUCH COOLER THAN RECENT NIGHTS. HOWEVER...DUE TO SOME WIND PERSISTING...AND THE PROSPECTS FOR INCREASING CLOUDS...HAVE RAISED FORECAST MINS A BIT...WITH LOWS GENERALLY FALLING INTO THE UPPER 30S TO LOWER 40S IN MOST AREAS BY DAYBREAK. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... WHILE SFC CDFNT WILL STALL WELL OFFSHORE...THE COLD AIR REMAINS SHALLOW AND THE H850 BAROCLINIC ZN/THERMAL RIBBON ONLY MOVES JUST OFFSHORE. ALL THE MODEL SUITE (NAM/GFS/ECMWF/CMC) HAS COME INTO AGREEMENT NOW SUN...WITH THE GFS JOINING THE OTHERS. STRONG 500HPA SHORT WV EJECTS E FM OH VLY...ACROSS THE BAROCLINIC ZONE... AND CLOUDS (DURING THE MORNING) AND WAA/OVERRUNNING RN (AFTN AND EVENING) SPREAD QUICKLY NE BACK INTO THE REGION SUNDAY. FORTUNATELY THIS SYSTEM IS FAST MOVING AND CYCLOGENISUS IS MINIMAL...RAIN EXITS OVERNIGHT WITH MOST AREAS SUBJECT TO 6-12 HOURS OF RAIN SUN AFTN AND EVENING. WITH CLOUDS AND CAA TEMPS WILL BE QUITE COOLER THAN THEY HAVE HAVE BEEN AND SVRL DEGREES BLO NORMALS. THERE WILL ALSO BE BRIEF PERIODS WHERE CONDS SUPPORT LK EFFECT -SHRA AND SH-SN AT NIGHT OVER HIR TRRN TNGT AND SUN NIGHT...BUT CHANGES IN FLOW AND WEAK FLOW WILL KEEP THIS CONFINED TO TUG HILL AND LT. AT 500HPA BROAD TROF OVER MID CONTINENT WILL RESULT IN SW FLOW ACROSS FCA..AS SERIES OF SHORT WVS DIVE INTO TROF MOST ROTATING WELL SOUTH OR NORTH OF REGION TILL WED. COLUMBUS DAY COOL HIGH PRESSURE BUILDS FM OH VLY INTO NEW ENG. SOME WK LK RESPONSE MAY LINGER INTO MONDAY MORNING IN N HERK/HAM COUNTIES...BUT WITH SFC/LLVL FLOW BCMG LT AND SW...THIS WILL END. SFC HI PRESSURE WILL REMAIN OVER THE RGN MON INTO WED MRNG. GEN PC/CLEAR CONDS...SOME PATCHY CLOUDS IN MID LVL WAA N TIER..BUT A FINE FALL PERIOD OF WX...NR NORMAL TEMPS...LT WINDS. BY WED 500 TROF AXIS HAS SHIFTED E TO GRTLKS...AND SERIES OF SHORT WVS DRIVES A CDFNT THRU FCA DURING LATE AFTN AND EVNG. THIS IS ANOTHER ANNA TYPE EVENT LIKE TDY (SAT) WITH PD OF LT RAIN POST FRONTAL. MORNING LOWS MONDAY AND TUES UNDER CLEAR SKIES AND SFC HI W/12.5 PLUS HOURS OF NIGHT WILL HAVE NO PROBLEM FALLING INTO MID 20S TO MID 30S. WOULD SUSPECT THIS TIME TOMORROW WE WILL BE CONSIDERING FROST AND FREEZE FLAGS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... OTHER THAN MINOR TIMING DIFFERENCES ECMWF AND GFS IN REASONABLE AGREEMENT. POPULATED WITH GMOS MAKING MINOR CHANGES. MID CONTINENT 500HPA TROF GRADUALLY SLIDES EASTWARD DURING THIS PERIOD AS A 500HPA RIDGE BUILDS IN ITS WAKE INTO THE GRTLKS TO END THE PERIOD. THE PARADE OF SHORT WAVES CONTINUE TO MIGRATE AROUND THE BASE OF THE TROF IN THE FAST FLOW. HIGH PRESSURE PASSES FM OH VLY TO MID ATLC STATES THUR WITH GENERALLY FAIR CONDS. CLOUDS MAY INCR N AHEAD OF NEXT SYSTEM THU AFTN AS PER GFS...BUT ECMWF KEEPS THIS MOISTURE N OF RGN. THE NEXT SHORT WV TO DRIVE A CDFNT THROUGH RGN IS FRI WITH WHAT APPEARS TO BE YET ANOTHER ANNA TYPE CDFNT WITH PD OF LT RAIN IN ITS WAKE. WITH TROF AXIS HAVING MOVED E TO OVER NY/NEW ENG FRI NIGHT...CAA SURGE WILL BE STRONGER THE PVS FEW...WITH MINS IN 20S TO LOW 30S MOST AREAS...AND WARMER READINGS CONFINED TO FAR SE. WHERE THE GROWING SEASON IS STILL BARELY HANGING ON...IT SHOULD BE OVER IN MOST AREAS BY THE WEEKEND. THE WEEKEND STARTS WITH ANOTHER HIGH PRESSURE AREA IN THE FAST FLOW PASSING ACROSS RGN SAT. HWVR THE PERIOD ENDS WITH 500HPA TROF EXITING...RIDGING IN ITS WAKE AND WAA OVERSPREADING THE RGN FM THE WEST IN SPLIT FLOW. TEMPS WILL REMAIN BLO NORMS FOR MOST OF THIS PERIOD. WHILE DRY AND FAIR MUCH OF THE TIME A CDFNT WILL BRING A CHC OF -SHRA FRI AND RAIN MAY OVERSPREAD THE REGION TO END THE WEEK. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE END OF THE TAF PERIOD ENDING AT 06Z MONDAY. THE EXCEPTION WILL BE AT KPOU WHERE VSBYS WILL BE MVFR/VFR WITH RAIN THIS AFTERNOON. FOR THE REMAINDER OF TONIGHT SOME MID AND HIGH LEVEL CLOUDINESS WILL MOVE INTO THE AREA AND THICKEN SUNDAY MORNING WITH BKN-OVC CONDITIONS. SOME RAIN WILL MOVE INTO THE REGION FROM SOUTH TO NORTH DURING THE AFTN/EVE HOURS. THE MODELS ARE NOT IN AGREEMENT YET WITH THE EXACT TIMING AND PLACEMENT OF THIS RAIN...BUT IT/S POSSIBLE THAT RAIN HOLDS OFF FOR KALB/KGFL UNTIL 00Z MONDAY. KPSF/KPOU HAVE A BETTER CHC OF SEEING SOME LIGHT RAIN DURING THE AFTN OR EVENING HOURS. FLYING CONDITIONS COULD DROP TO MVFR WITHIN ANY RAINFALL. WESTERLY WINDS WILL CONTINUE TO BE RATHER LIGHT. OUTLOOK... SUN NT...VFR/MVFR. CHC/LIKELY -SHRA SUN EVENING. MON-TUE NT...VFR. NO SIG WX. WED...VFR. CHC MVFR IN SHOWERS. THU...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER RELATED ISSUES ARE EXPECTED. A WAVE OF LOW PRESSURE WILL MOVE ALONG THE FRONTAL BOUNDARY STALLED JUST TO OUR SOUTH GIVING MOST AREAS OVER A QUARTER INCH OF RAIN SUNDAY. HIGH PRESSURE WILL BUILD INTO THE REGION ON MONDAY WITH FAIR AND COOL WEATHER INTO WEDNESDAY WHEN ANOTHER FRONTAL SYSTEM WILL BRING A PERIOD OF SHOWERS. && .HYDROLOGY... NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT 7 DAYS. AROUND A QUARTER INCH OF RAINFALL IS EXPECTED SUNDAY AFTERNOON/EVENING AND WEDNESDAY AFTERNOON/EVENING. IN THE TUG HILL PLATEAU LAKE EFFECT RAIN SHOWERS...AND OVER THE HIGHER TERRAIN AT NIGHT SNOW SHOWERS...WILL PRODUCE UP TO AN INCH LIQUID TOTAL THIS WEEK. THESE AMOUNTS WILL BE INSUFFICIENT TO PRODUCE MUCH RESPONSE IN RIVERS AND CREEKS THIS WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS/SNYDER NEAR TERM...FRUGIS/KL SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...11/FRUIGIS FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
105 AM EDT SUN OCT 7 2012 .SYNOPSIS... MUCH COOLER AIR WILL CONTINUE TO STREAM INTO OUR REGION OVERNIGHT AS WEAK HIGH PRESSURE CRESTS ACROSS THE REGION. LOW PRESSURE WILL MOVE ALONG A FRONTAL BOUNDARY STALLED JUST TO OUR SOUTH GIVING US MORE UNSETTLED WEATHER FOR SUNDAY AFTERNOON INTO SUNDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION ON MONDAY AND BRING FAIR AND SEASONABLE WEATHER FOR THE FIRST HALF OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1 AM EDT...A BAND OF LAKE EFFECT RAIN SHOWERS HAS DEVELOPED OFF LAKE ONTARIO. WHILE THE MAJORITY OF THESE RAIN SHOWERS ARE REMAINING CLOSE TO THE LAKESHORE AND ACROSS THE TUG HILL...A FEW SHOWERS WILL MAKE IT INTO THE FAR WESTERN ADIRONDACKS. AS THE FLOW SHIFTS...THIS BAND WILL GRADUALLY SHIFT SOUTH...POSSIBLY AFFECTING PARTS OF THE WESTERN MOHAWK VALLEY BY LATE TONIGHT. THIS IS BEING MODELED WELL BY THE LATEST HRRR AND LOCAL WRF. MEANWHILE...A SFC FRONTAL BOUNDARY CONTINUES TO MOVE TO THE SOUTH AND EAST OF OUR AREA ACROSS EASTERN NEW ENGLAND AND DOWN OFF THE MID ATLANTIC SEABOARD. MID AND HIGH LEVEL CLOUDS ARE ALREADY BEGINNING TO STREAK INTO THE REGION FROM THE SOUTHWEST...AND WILL CONTINUE TO INCREASE TOWARD DAYBREAK AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONTAL BOUNDARY TO OUR SOUTH. MIN TEMPS OVERNIGHT WILL BE MUCH COOLER THAN RECENT NIGHTS. HOWEVER...DUE TO SOME WIND PERSISTING...AND THE PROSPECTS FOR INCREASING CLOUDS...HAVE RAISED FORECAST MINS A BIT...WITH LOWS GENERALLY FALLING INTO THE UPPER 30S TO LOWER 40S IN MOST AREAS BY DAYBREAK. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... WHILE SFC CDFNT WILL STALL WELL OFFSHORE...THE COLD AIR REMAINS SHALLOW AND THE H850 BAROCLINIC ZN/THERMAL RIBBON ONLY MOVES JUST OFFSHORE. ALL THE MODEL SUITE (NAM/GFS/ECMWF/CMC) HAS COME INTO AGREEMENT NOW SUN...WITH THE GFS JOINING THE OTHERS. STRONG 500HPA SHORT WV EJECTS E FM OH VLY...ACROSS THE BAROCLINIC ZONE... AND CLOUDS (DURING THE MORNING) AND WAA/OVERRUNNING RN (AFTN AND EVENING) SPREAD QUICKLY NE BACK INTO THE REGION SUNDAY. FORTUNATELY THIS SYSTEM IS FAST MOVING AND CYCLOGENISUS IS MINIMAL...RAIN EXITS OVERNIGHT WITH MOST AREAS SUBJECT TO 6-12 HOURS OF RAIN SUN AFTN AND EVENING. WITH CLOUDS AND CAA TEMPS WILL BE QUITE COOLER THAN THEY HAVE HAVE BEEN AND SVRL DEGREES BLO NORMALS. THERE WILL ALSO BE BRIEF PERIODS WHERE CONDS SUPPORT LK EFFECT -SHRA AND SH-SN AT NIGHT OVER HIR TRRN TNGT AND SUN NIGHT...BUT CHANGES IN FLOW AND WEAK FLOW WILL KEEP THIS CONFINED TO TUG HILL AND LT. AT 500HPA BROAD TROF OVER MID CONTINENT WILL RESULT IN SW FLOW ACROSS FCA..AS SERIES OF SHORT WVS DIVE INTO TROF MOST ROTATING WELL SOUTH OR NORTH OF REGION TILL WED. COLUMBUS DAY COOL HIGH PRESSURE BUILDS FM OH VLY INTO NEW ENG. SOME WK LK RESPONSE MAY LINGER INTO MONDAY MORNING IN N HERK/HAM COUNTIES...BUT WITH SFC/LLVL FLOW BCMG LT AND SW...THIS WILL END. SFC HI PRESSURE WILL REMAIN OVER THE RGN MON INTO WED MRNG. GEN PC/CLEAR CONDS...SOME PATCHY CLOUDS IN MID LVL WAA N TIER..BUT A FINE FALL PERIOD OF WX...NR NORMAL TEMPS...LT WINDS. BY WED 500 TROF AXIS HAS SHIFTED E TO GRTLKS...AND SERIES OF SHORT WVS DRIVES A CDFNT THRU FCA DURING LATE AFTN AND EVNG. THIS IS ANOTHER ANNA TYPE EVENT LIKE TDY (SAT) WITH PD OF LT RAIN POST FRONTAL. MORNING LOWS MONDAY AND TUES UNDER CLEAR SKIES AND SFC HI W/12.5 PLUS HOURS OF NIGHT WILL HAVE NO PROBLEM FALLING INTO MID 20S TO MID 30S. WOULD SUSPECT THIS TIME TOMORROW WE WILL BE CONSIDERING FROST AND FREEZE FLAGS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... OTHER THAN MINOR TIMING DIFFERENCES ECMWF AND GFS IN REASONABLE AGREEMENT. POPULATED WITH GMOS MAKING MINOR CHANGES. MID CONTINENT 500HPA TROF GRADUALLY SLIDES EASTWARD DURING THIS PERIOD AS A 500HPA RIDGE BUILDS IN ITS WAKE INTO THE GRTLKS TO END THE PERIOD. THE PARADE OF SHORT WAVES CONTINUE TO MIGRATE AROUND THE BASE OF THE TROF IN THE FAST FLOW. HIGH PRESSURE PASSES FM OH VLY TO MID ATLC STATES THUR WITH GENERALLY FAIR CONDS. CLOUDS MAY INCR N AHEAD OF NEXT SYSTEM THU AFTN AS PER GFS...BUT ECMWF KEEPS THIS MOISTURE N OF RGN. THE NEXT SHORT WV TO DRIVE A CDFNT THROUGH RGN IS FRI WITH WHAT APPEARS TO BE YET ANOTHER ANNA TYPE CDFNT WITH PD OF LT RAIN IN ITS WAKE. WITH TROF AXIS HAVING MOVED E TO OVER NY/NEW ENG FRI NIGHT...CAA SURGE WILL BE STRONGER THE PVS FEW...WITH MINS IN 20S TO LOW 30S MOST AREAS...AND WARMER READINGS CONFINED TO FAR SE. WHERE THE GROWING SEASON IS STILL BARELY HANGING ON...IT SHOULD BE OVER IN MOST AREAS BY THE WEEKEND. THE WEEKEND STARTS WITH ANOTHER HIGH PRESSURE AREA IN THE FAST FLOW PASSING ACROSS RGN SAT. HWVR THE PERIOD ENDS WITH 500HPA TROF EXITING...RIDGING IN ITS WAKE AND WAA OVERSPREADING THE RGN FM THE WEST IN SPLIT FLOW. TEMPS WILL REMAIN BLO NORMS FOR MOST OF THIS PERIOD. WHILE DRY AND FAIR MUCH OF THE TIME A CDFNT WILL BRING A CHC OF -SHRA FRI AND RAIN MAY OVERSPREAD THE REGION TO END THE WEEK. && .AVIATION /05Z SUNDAY THROUGH THURSDAY/... VFR FLYING CONDITIONS ARE EXPECTED THROUGH MUCH OF THE OVERNIGHT HOURS WITH JUST FEW-SCT STRATOCU CLOUDS AROUND 4-6 KFT...MAINLY DURING THE EVENING HOURS. SOME MID AND HIGH LEVEL CLOUDINESS WILL MOVE INTO THE AREA TOWARDS DAYBREAK. LIGHT WESTERLY WINDS WILL BE IN PLACE TONIGHT...AND WITH DEWPOINTS DROPPING DOWN INTO THE 30S...NO RADIATIONAL FOG IS EXPECTED TO DEVELOP TONIGHT. BKN-OVC MID LEVEL CLOUDINESS WILL BE IN PLACE FOR SUNDAY MORNING. SOME RAIN WILL MOVE INTO THE REGION FROM SOUTH TO NORTH DURING THE AFTN/EVE HOURS. THE MODELS ARE NOT IN AGREEMENT YET WITH THE EXACT TIMING AND PLACEMENT OF THIS RAIN...BUT IT/S POSSIBLE THAT RAIN HOLDS OFF FOR KALB/KGFL UNTIL 00Z MONDAY. KPSF/KPOU HAVE A BETTER CHC OF SEEING SOME LIGHT RAIN DURING THE AFTN OR EVENING HOURS. FLYING CONDITIONS COULD DROP TO MVFR WITHIN ANY RAINFALL. WESTERLY WINDS WILL CONTINUE TO BE RATHER LIGHT. OUTLOOK... SUN NT...VFR/MVFR. CHC/LIKELY -SHRA SUN EVENING. MON-TUE NT...VFR. NO SIG WX. WED...VFR. CHC MVFR IN SHOWERS. THU...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER RELATED ISSUES ARE EXPECTED. A WAVE OF LOW PRESSURE WILL MOVE ALONG THE FRONTAL BOUNDARY STALLED JUST TO OUR SOUTH GIVING MOST AREAS OVER A QUARTER INCH OF RAIN SUNDAY. HIGH PRESSURE WILL BUILD INTO THE REGION ON MONDAY WITH FAIR AND COOL WEATHER INTO WEDNESDAY WHEN ANOTHER FRONTAL SYSTEM WILL BRING A PERIOD OF SHOWERS. && .HYDROLOGY... NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT 7 DAYS. AROUND A QUARTER INCH OF RAINFALL IS EXPECTED SUNDAY AFTERNOON/EVENING AND WEDNESDAY AFTERNOON/EVENING. IN THE TUG HILL PLATEAU LAKE EFFECT RAIN SHOWERS...AND OVER THE HIGHER TERRAIN AT NIGHT SNOW SHOWERS...WILL PRODUCE UP TO AN INCH LIQUID TOTAL THIS WEEK. THESE AMOUNTS WILL BE INSUFFICIENT TO PRODUCE MUCH RESPONSE IN RIVERS AND CREEKS THIS WEEK. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS/SNYDER NEAR TERM...KL/FRUGIS SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...FRUGIS FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
243 AM MDT SUN OCT 7 2012 .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 243 AM MDT SUN OCT 7 2012 FORECAST CONCERNS WILL BE HOW MUCH THE TEMPERATURES MODERATE THROUGH MONDAY BEFORE THE NEXT COLD FRONT MOVES IN TO COOL OFF TUESDAY. SATELLITE CONTINUING TO SHOW AN AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA. FLOW DOMINATED BY A BLOCK ALONG THE WEST COAST AND A TROUGH OVER THE CENTRAL AND EASTERN PORTION OF THE COUNTRY. COLD AND MOIST AIR MASS REMAINS OVER THE CENTRAL PORTION OF THE COUNTRY. MODELS INITIALIZED FINE AT THE JET AND MID LEVELS. NAM WAS CATCHING THE SURFACE RIDGING AND WIND FIELD IN OUR AREA THE BEST. NAM AND RUC APPEAR TO BE CATCHING THE STRATUS FIELD THE BEST. THE GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE REST ON THE LOW LEVEL THERMAL FIELD. TODAY/TONIGHT...STRATUS KEEPS EDGING EVER SO SLOWLY SOUTHWEST. NOT SURE HOW MUCH FURTHER IT WILL GO. LOCATIONS ON THE EDGE OF THIS CLOUD FIELD ARE NOT THAT FAR AWAY FROM REACHING THE NEEDED TEMPERATURES FOR THE FREEZE WARNING TO VERIFY. AT THIS TIME I WILL LET THE FREEZE WARNING CONTINUE BUT FEELING IS THAT THE FAR SOUTHWEST AND WESTERN PORTIONS WILL NOT MAKE IT. SOME FOG HAS DEVELOPED. THE 00Z NAM DRASTICALLY OVERDID THE FOG. THE 06Z NAM IS NOW MORE REALISTIC AND DEVELOPING FOG IN AREAS THAT HAVE CLEARED. THE HRRR AND RUC DO NOT AGREE WITH EACH OTHER BUT TEND TO FAVOR THE WEST AND MORE IN LOCATIONS THAT HAVE THE STRATUS. AT THIS TIME WILL ADD FOG PER THE LATEST NAM WHICH DOES MAKE SENSE. WEAK LEFT FRONT QUADRANT OF THE UPPER JET AND A RATHER STRONG SHORTWAVE MOVES THROUGH DURING THE LATE MORNING AND AFTERNOON. WILL HAVE TO KEEP WATCHING BUT THESE FEATURES LOOK TO SPREAD SOME HIGHER LEVEL CLOUD COVER ACROSS THE AREA. TEMPERATURES TODAY WILL BE AFFECTED BY HOW FAST THE STRATUS LEAVES WHICH LOOKS TO BE BY LATE MORNING. HAVE AN AREA IN THE NORTHERN PORTION OF THE AREA THAT HAD SIX PLUS INCHES OF SNOW YESTERDAY. AREAS DOWNSTREAM OF SNOW FIELD COULD BE AFFECT. WITH WARM GROUND WOULD IMAGINE THAT SNOW WOULD MELT A LITTLE FASTER THAN NORMAL. WILL DEFINITELY HAVE AN AFFECT TODAY ON THE TEMPERATURES AND MADE THAT AREA COOLER THAN SURROUNDING LOCATIONS. IF STRATUS HOLDS ON LONGER ALL THE TEMPERATURES MAY END UP BEING TOO WARM. MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF UPPER JET MOVES ACROSS AT THE BEGINNING OF THE DAY. IT LOOKS LIKE IT WILL SPREAD SOME CLOUDS ACROSS THE AREA. MODELS SHOW GOOD DOWNSLOPE WINDS THROUGH MOST OF THE DAY UNTIL THEY BECOME LIGHTER AND MORE IN THE MIDDLE OF THE AFTERNOON. SO WILL TREND TOWARD THE WARMER GUIDANCE. THERE IS SOME MODEL DIFFERENCES IN HOW TO HANDLE THE SYSTEM DIGGING OUT OF CENTRAL CANADA. THE NAM IS FASTER AND DEEPER. GFS IS NOT AS DEEP. OTHER MODELS ARE FAIRLY DEEP...SLOWER AND ARE A LITTLE FURTHER SOUTHWEST. AS A CONSEQUENCE THE NAM IS THE FASTEST TO PUSH THE FRONT THROUGH AND THROUGH MOST OF THE AREA BY 12Z. IT IS ALWAYS POSSIBLE IN THIS SCENARIO THAT FRONTS WILL COME IN FASTER BUT AM LEARY OF THE NAM A LITTLE. SO WENT IN THE MIDDLE OF THE SOLUTIONS. TUESDAY/TUESDAY NIGHT...ABOVE MENTIONED JET MOVES ACROSS DURING THE MORNING BUT MODELS INDICATE VERY LITTLE CLOUD COVER WILL BE GENERATED BY THIS FEATURE. ALL THE MODELS HAVE THE FRONT THROUGH THE FORECAST AREA BY 18Z. THERE IS A LITTLE BIT OF SPREAD IN HOW MUCH COOLING TAKES PLACE. THE NAM IS THE WARMEST BUT NOT BY MUCH AND THE ECMWF THE COOLEST. THE OTHER MODELS CLUSTER IN THE MIDDLE. AT THIS TIME WILL GO WITH A COMPROMISE OF TEMPERATURES WHICH DOES LOWER THE MAXES A LITTLE. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 243 AM MDT SUN OCT 7 2012 THE UPPER PATTERN DURING THIS PERIOD WILL TRANSITION FROM FAST NORTHWEST FLOW ALOFT ON WED TO UPPER RIDGING THU-EARLY FRI TO STRONG SOUTHWEST FLOW LATER FRI-SAT AS THE UPPER LOW APPROACHING CALIFORNIA EJECTS NORTHEAST ACROSS THE CENTRAL HIGH PLAINS. NUMERICAL GUIDANCE HAS VASTLY DIFFERING SOLUTIONS ON WHERE AND HOW FAST THE UPPER LOW LIFTS OUT OF THE SOUTHWEST U.S. WHICH IS ULTIMATELY TIED TO THE LOCATION AND INTENSITY OF THE NEXT UPSTREAM TROUGH. THE EC IS NOW CONSIDERABLY FASTER AND MUCH FURTHER NORTH COMPARED TO GFS. SATURDAY MORNING THE EC HAS THE UPPER LOW OVER CENTRAL NEBRASKA WHILE GFS HOLDS IT BACK OVER THE FOUR CORNERS. THE GEM WAS PRETTY MUCH IN STEP WITH THE GFS THRU 144 HRS /FRI/. NEEDLESS TO SAY...CONFIDENCE IS LOW IN THE TIMING AND AMOUNT OF ASSOCIATED PRECIP IN THE FRI-SAT TIME FRAME. EXPERIENCE WOULD FAVOR A SLOWER /GFS/ MOVEMENT BUT A BLEND IS PROBABLY APPROPRIATE AT THIS POINT. WHICHEVER MODEL VERIFIES... IF EITHER ONE DOES... WILL ALSO MAKE A BIG DIFFERENCE IN THE POTENTIAL TO GET DRY SLOTTED. WHATEVER THE OUTCOME...LOOKS LIKE A RETURN TO MORE TYPICAL OCTOBER TEMPERATURES GIVEN THE UPPER PATTERN CHANGE DURING PERIOD. AT THE SURFACE...ONE LAST CANADIAN HIGH PRESSURE AREA WILL DROP SOUTHEAST INTO THE AREA THURSDAY BEFORE UPPER RIDGING AND SOUTHWEST FLOW ALOFT TAKE OVER. THE EC IS A LITTLE SLOWER WITH THE COLD FRONTAL PASSAGE COMPARED TO GFS/GEM WHICH COULD MAKE THURSDAY MAX TEMPS A LITTLE TRICKY. CURRENT FORECAST HAS MAX TEMPERATURES IN THE UPPER 60S/LOWER 70S BEFORE FRONTAL PASSAGE. THE NEXT SHOT AT PRECIP LOOKS TO BE TOWARD THE END OF THIS FORECAST PERIOD WITH TIMING DEPENDING ON SPEED AT WHICH UPPER LOW EJECTS NORTHEAST. THE EC BRINGS IN POTENTIAL FOR SHOWERS AND THUNDERSTORMS EARLY FRIDAY MORNING WHILE GFS TIMING IS FRIDAY NIGHT INTO SATURDAY. CURRENT FORECAST IS A BLEND OF NUMERICAL GUIDANCE AND BRINGS IN CHANCE POPS STARTING FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1115 PM MDT SAT OCT 6 2012 FOR KGLD MVFR CIGS EXPECTED THROUGH 18Z OR SO AS AXIS OF LOW LEVEL MOISTURE REMAINS OVER THE TERMINAL. AFTER 18Z VFR CONDITIONS EXPECTED. AT KMCK SMALL AREA OF STRATUS AND IFR CIGS CURRENTLY OVER THE TERMINAL. THIS SHOULD CONTINUE FOR A FEW HOURS BEFORE MOVING OUT OF THE AREA LEAVING VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...FREEZE WARNING UNTIL 9 AM MDT /10 AM CDT/ SUNDAY FOR KSZ001>004- 013>016-027>029-041-042. CO...FREEZE WARNING UNTIL 9 AM MDT SUNDAY FOR COZ090>092. NE...FREEZE WARNING UNTIL 9 AM MDT /10 AM CDT/ SUNDAY FOR NEZ079>081. && $$ SHORT TERM...BULLER LONG TERM...DLF AVIATION...DDT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1219 AM CDT SUN OCT 7 2012 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1256 PM CDT SAT OCT 6 2012 A DEEP LONGWAVE TROUGH ENCOMPASSED MUCH OF THE NORTHERN CONUS WITH 250MB CYCLONICALLY CURVED FLOW FROM THE GREAT BASIN THROUGH THE GREAT PLAINS TO THE GREAT LAKES REGION. WITHIN THE LONGWAVE TROUGH...A SHORTWAVE TROUGH WAS MOVING SOUTHEAST THROUGH WESTERN NEBRASKA EARLY SATURDAY. 12Z UPPER AIR ANALYSIS REVEALED 700MB FRONTOGENETIC ZONE EXTENDING FROM SOUTHERN WYOMING THROUGH EASTERN COLORADO TO SOUTHWESTERN KANSAS WITH SATURATED OR NEAR SATURATED AIR (700MB DEWPOINT DEPRESSIONS 0 OR 1 DEGC AT KRIW, KDNR, KDDC, KAMA, KOUN). PRECIPITATION IN THE FORM OF RAIN AND SNOW EXTENDED ALL ALONG THE STRONGEST ZONE OF MID LEVEL FRONTOGENESIS (THE STRONGEST OF WHICH FROM NORTHEAST COLORADO TO NORTHWEST KANSAS TO FAR SOUTHWEST NEBRASKA AS OF 17Z). LIGHTER BANDED PRECIPITATION WAS FOUND ACROSS SOUTHWEST KANSAS WHERE 0.06 INCHES OF PRECIPITATION WAS MEASURED SO FAR AT DODGE CITY (ALL IN THE FORM OF RAIN). SNOW WAS REPORTED AS FAR SOUTHEAST AS DIGHTON...AND VERY BRIEFLY MIXED IN WITH RAIN ACROSS THE NORTHWEST PORTIONS OF FORD COUNTY DURING ONE OF THE HEAVIER BANDS EARLIER THIS MORNING. IT SEEMS THE SNOW LINE IS MATCHING UP WELL WITH THE RAP ANALYZED 900 FT AGL FREEZING LEVEL...WHICH EXTENDED FROM ROUGHLY GARDEN CITY TO DIGHTON (AND POINTS NORTHWEST) AT 18Z. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 316 PM CDT SAT OCT 6 2012 THIS EVENING: MID LEVEL FRONTOGENESIS (MAINLY CENTERED AROUND 700MB) WILL CONTINUE TO DECREASE ACROSS WEST CENTRAL AND CENTRAL KANSAS AS THE MID LEVEL SHORTWAVE TROUGH ACROSS SOUTHWEST NEBRASKA MOVES TOWARD SOUTHEAST NEBRASKA. MID LEVEL DRYING FROM 800 TO 500MB (AND ABOVE THROUGH THE UPPER TROPOSPHERE) WILL INCREASE AS SUBSIDENCE PREVAILS IN THE WAKE OF THE PRIMARY SHORTWAVE TROUGH. MOISTURE AND ATTENDANT CLOUD IN THE LOWER TROPOSPHERE (800-900MB) WILL ALSO BE DECREASING...HOWEVER RATE OF DECREASE ACROSS SOUTHWEST AND WEST CENTRAL KANSAS IS STILL A FAIRLY CHALLENGING FORECAST AS LOW STRATUS WILL BE DIFFICULT TO DISLODGE AS REMNANT LOW LEVEL MOISTURE RECIRCULATES AROUND THE ANTICYCLONE IN THIS LAYER. FEEL THAT CLOUDS IN THE 800-900MB LAYER WILL SCATTER OUT SLOWLY FROM 00-06Z TONIGHT...AND MOST PROMINENT FARTHER NORTHEAST AWAY FROM COLORADO. OVERNIGHT: A 1030MB SURFACE HIGH WILL BE MOVING SOUTH-SOUTHEAST WITH CENTER OF SURFACE HIGH TAKING A TRACK FROM ROUGHLY WRAY, COLORADO TO DODGE CITY TONIGHT. ALONG THE TRACK OF THE SURFACE HIGH SKY SHOULD CLEAR OUT AFTER MIDNIGHT...AND TEMPERATURES WILL FALL INTO THE LOWER 30S RATHER QUICKLY ONCE CLOUDS CLEAR. TEMPERATURES WILL MOST LIKELY FALL TO 28 TO 30 DEGREES NORTH OF THE ARKANSAS RIVER BY 08 OR 09Z AND REMAIN IN THIS RANGE FOR PROBABLY 4 OR 5 HOURS...WITH MINIMUM AROUND SUNRISE OF 25 TO 27 DEGREES NORTH OF A DIGHTON TO NESS CITY TO LACROSSE LINE. THIS IS MORE OR LESS A CONTINUATION OF THE PREVIOUS FORECAST AND AM NOT MAKING ANY CHANGES TO THE GOING FREEZE HEADLINES. WILL CONTINUE THE HARD FREEZE WARNING (28 DEGREES OR BELOW FOR LOWS) NORTH OF A JOHNSON TO BUCKLIN TO STAFFORD LINE. SOUTH OF THIS LINE TO THE OKLAHOMA BORDER WILL CONTINUE WITH THE FREEZE WARNING FOR LOWS 29 TO 32 DEGREES. MUCH, IF NOT ALL, OF WEST CENTRAL, SOUTHWEST, AND SOUTH CENTRAL KANSAS WILL SEE THE END TO THE GROWING SEASON WITH THESE FORECAST TEMPERATURES TONIGHT. SUNDAY: A SECONDARY MINOR SHORTWAVE DISTURBANCE WILL BE ROTATING AROUND THE MEAN TROUGH AXIS FROM SOUTHERN WYOMING TO NORTHEASTERN NEW MEXICO...WHICH MAY BRING SOME MID LEVEL CLOUD BACK TO FAR SOUTHWEST KANSAS BY DAYBREAK...HOWEVER NO OTHER SENSIBLE WEATHER IMPACTS ARE EXPECTED WITH THIS FINAL SHORTWAVE TROUGH PASSAGE. THE SURFACE HIGH WILL SHIFT INTO THE RED RIVER VALLEY BY MIDDAY SUNDAY...BUT OVERALL PRESSURE GRADIENT WILL REMAIN RATHER WEAK WITH SOUTHWEST WINDS 8 TO 10 KNOTS EXPECTED. A WARMING OF THE LOWER TROPOSPHERE FROM DOWNSLOPE MOMENTUM (850MB TEMPS INCREASING TO +5 TO +9C FROM EAST TO WEST) WILL ALLOW SURFACE TEMPERATURES TO WARM UP WELL INTO THE MID TO UPPER 50S...ESPECIALLY ACROSS CENTRAL AND SOUTH CENTRAL KANSAS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 345 PM CDT SAT OCT 6 2012 MONDAY: BROAD 500-250 HPA WNW FLOW IS EXPECTED MONDAY. THIS ORTHOGONAL FLOW WRT THE ROCKIES WILL ALLOW FOR A LEE TROUGH TO FORM MONDAY FROM THE SURFACE UP TO 850 HPA. AS A RESULT, A WEAK WARM AIR ADVECTION REGIME IS EXPECTED WITH HIGHS MODERATING TO THE UPPER 60S DEG F TO AROUND 70 DEG F. A DRY FORECAST IS EXPECTED FOR THE BEGINNING OF THE WORK WEEK AS THE REGION WILL BE FREE OF ANY SYNOPTIC DISTURBANCES AND ASSOCIATED LIFT. TUESDAY: THE SYNOPTIC PATTERN CHANGES TUESDAY AS A BROAD POSITIVELY TILTED UPPER LEVEL SHORTWAVE TROF EJECTS FROM THE CANADIAN PRAIRIES AND ACROSS THE NORTHERN PLAINS. THIS UL FEATURE WILL USHER IN A PASSAGE OF A COLD FRONT. HAVE USED 12Z ECMWF AS GUIDANCE FOR TEMPERATURES AS THE GFS CONTINUES TO PERFORM POORLY (IN THIS CASE, USUALLY TOO AGGRESSIVE WITH THE FROPA). HIGHS WILL VARY ACROSS THE REGION WITH LOW TO MID 60S DEG F ACROSS THE INTERSTATE 70 CORRIDOR TO MID 70S DEG F ACROSS EXTREME SOUTHWEST KANSAS. THIS FRONT WILL BE DRY WITH A LACK OF BOUNDARY LAYER MOISTURE IN PLACE. WILL KEEP POPS NEAR ZERO PERCENT. SFC WINDS DON`T LOOK PARTICULARLY STRONG WITH THIS HIGH AS 850 HPA WINDS ARE ONLY FORECAST TO BE IN THE 20-25 KT RANGE. WEDNESDAY: A RIDGE OF HIGH PRESSURE WILL TRANSLATE ACROSS THE SUNFLOWER STATE WEDNESDAY IN THE WAKE OF THE DENSITY GRADIENT. HIGHS IN THE 60S DEG F ARE EXPECTED AS FAIRLY COOL 850 HPA TEMPERATURES (9-13 DEG C) ARE FORECAST IN ASSOCIATION WITH THE AFOREMENTIONED COOL HIGH PRESSURE CENTER MOVING ACROSS THE STATE. WILL ALSO RUN WITH THE ALLBLEND POPS (AROUND 3 PERCENT) FOR THE MIDDLE PORTION OF THE WORK WEEK. THURSDAY AND BEYOND: THE FORECAST BECOMES MORE INTERESTING TOWARDS THE END OF THE WORK WEEK ALTHOUGH SYNOPTIC AND MESOSCALE DETAILS ARE VERY UNCERTAIN AT THIS POINT. FOR EXAMPLE, YESTERDAYS ECMWF RUN HAD THE WARM SECTOR (HIGHER THETA-E AIR) SPREADING NORTHWARD IN ASSOCIATION WITH THE PASSAGE OF A WARM FRONT FRIDAY. TODAY`S 12Z ECMWF RUN KEEPS THAT BOUNDARY SOUTH OF THE REGION FRIDAY. THIS BOUNDARY PLACEMENT WILL HAVE SIGNIFICANT IMPACTS IN TERMS OF SENSIBLE WEATHER AS A WAA PATTERN/THETA-E ADVECTION ALONG SAID FRONT COULD LEAD TO THE DEVELOPMENT OF CONVECTION ACROSS THE PLAINS. FOR NOW WILL GO WITH A BLEND OF THE ALLBLEND POPS ALTHOUGH WILL SMOOTH POPS TOWARDS A BIAS TO THE ECMWF. THE GFS WAS GENERALLY DISREGARDED AS THE MODEL CONTINUES TO BE VERY PROGRESSIVE WITH UL FEATURES THAT WILL PROBABLY SLOW DOWN WITH TIME. IT SHOULD BE NOTED THAT MUCH UNCERTAINTY EXISTS WITH THE EVOLUTION OF THE DESERT SOUTHWEST UL LOW THAT WILL BE THE IMPETUS FOR CONVECTION. IT ALSO SHOULD BE NOTED THAT THERE IS THE POSSIBILITY OF SEVERE CONVECTION, PARTICULARLY FRIDAY AND SATURDAY. WARM SECTOR PLACEMENT AND ASSOCIATED REDISTRIBUTION OF ENERGY PER UNIT MASS (I.E. CAPE) IS UNCERTAIN. REGARDLESS OF WHEREVER THE WARM SECTOR WILL BE, THE ECMWF SHOWS SIGNIFICANT BOUNDARY LAYER MOISTURE WORKING ITS WAY NORTH FROM THE GULF OF MEXICO. KINEMATIC PROFILES ALSO STRENGTHEN WITH TIME AS THE UL LOW MOVES CLOSER TO KANSAS WITH 250 HPA FLOW INCREASING TO 100 KT, 500 HPA FLOW INCREASING TO 60 KT, AND FAIRLY STRONG AND VEERING FLOW FROM THE SFC THROUGH 700 HPA. SEVERE WEATHER EPISODES IN OCTOBER ARE NOT UNUSUAL FOR THE PLAINS. IN FACT, THERE WERE TORNADOES LAST OCTOBER ACROSS THE REGION LAST YEAR. IT IS TOO EARLY TO DETERMINE STORM MODE AND PLACEMENT AT THIS TIME BUT IT IS SOMETHING TO WATCH FOR IN FUTURE MODEL RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1219 AM CDT SUN OCT 7 2012 MVFR CIGS AT GARDEN CITY WILL GRADUALLY INCREASE TO VFR AROUND 09Z-10Z AS DRIER AIR MOVES INTO SOUTHWEST KANSAS. VFR CIGS AT DODGE CITY WILL CONTINUE THROUGH MOST OF THE NIGHTTIME HOURS BEFORE SCATTERING OUT. LOOK FOR MOSTLY CLEAR SKIES TO CONTINUE AT HAYS. LIGHT AND VARIABLE WINDS WILL BECOME SOUTHWESTERLY AT 10 TO 12 KNOTS BY MIDDAY SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 34 69 43 69 / 0 0 0 0 GCK 32 69 42 67 / 0 0 0 0 EHA 35 67 44 77 / 0 0 0 0 LBL 34 67 42 73 / 0 0 0 0 HYS 34 70 44 66 / 0 0 0 0 P28 35 69 46 71 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... HARD FREEZE WARNING UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR KSZ030-031-043>046-061>066-074>079. FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR KSZ080-081- 084>090. && $$ SYNOPSIS...UMSCHEID SHORT TERM...UMSCHEID LONG TERM...SUGDEN AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1247 AM EDT SUN OCT 07 2012 ...Updated Aviation Discussion... .Forecast Update... Updated at 1027 PM EDT Sat Oct 6 2012 HRRR and RAP show KY staying dry tonight and this is supported by regional radars and upstream obs. Decent band of reflectivities passed over Logan and Simpson Counties within the last hour but neither Mesonet station reported measurable rainfall. So, will back off on PoPs a bit. Will still keep some low chances going far south though in case any activity can blossom ahead of the approaching upper trof or slip over the border from Tennessee. && .Short Term (Today through Sunday)... Issued at 300 PM EDT Sat Oct 6 2012 A persistent Rex Block at 500mb just off the Pacific Coast has allowed northerly flow to develop downstream across the Upper Midwest. A chilly Canadian airmass has already penetrated practically as far south as the Texas Gulf coast, and remains banked up against higher terrain in New Mexico and Colorado. Clouds will increase this evening as one of several flat disturbances embedded within a broader 500mb cyclonic gyre scoots across Missouri. Both the GFS and NAM models take this feature across Tennessee and southern Kentucky during the overnight hours. A light chilly rain may develop across our southern counties later this evening, ending around dawn across our southern Bluegrass or Lake Cumberland Region. Precipitation totals will stay light, totaling around two tenths of an inch or less. Feel that Louisville and possible Lexington will stay north of this potential strip of precipitation. Expect a cloudy cool night with lows ranging from just under 40 to the lower 40s. Skies will clear pretty readily Sunday morning as this 500mb wave passes and subsidence overspreads the area. Canadian high pressure will settle over the southern plains by Sunday afternoon, with an axis extending east across the Commonwealth. Light north winds Sunday afternoon will become calm overnight through Monday. Early Monday will provide our best chance for widespread frost and even a chance of a light freeze across some of our colder rural locations. Frost chances will depend on how clear we become by early Monday. High clouds associated with a disturbance over Tennessee may spread as far north as Interstate 64 early Monday. This may, if thick enough, limit frost chances across our south. Agricultural interests should however, plan on at least some frost across southern Indiana and north central Kentucky. Some lows early Monday may reach or approach 32 for a few hours. .Long Term (Monday - Saturday)... Issued at 300 PM EDT Sat Oct 6 2012 High pressure will be over the region Monday morning at the same time a vortmax is crossing the region aloft. Clouds associated with this shortwave will be over or just east of the eastern forecast area at the start of this period. During the day Monday and continuing into Tuesday, the high will become centered over New England. Tuesday night, a cold front will move into the Midwest. Moisture ahead of this front is not that impressive but will be enough to warrant a chance for rain to come through the forecast area. After that front, another cold shot of Canadian air will build into the region, with high pressure becoming centered over the region Thursday morning. Deterministic and Ensemble models support this scenario, meaning another chilly morning with more frost possible Thursday morning. Progressive flow aloft, with persistent troughiness across eastern Canada, will bring another moisture-starved front through the region Friday morning. The high behind this front looks to move more to our north. This may allow for a quicker return of moisture into the area for next weekend. 00Z ECMWF and latest GFS/DGEX all indicate some weak warm frontal-type forcing across the region Saturday, with the latter two bringing rain into the region. For now will lean toward the ECMWF solution, which keeps the best rain chances to our northwest. && .Aviation (06Z TAF Issuance)... Issued at 1247 PM EDT Sun Oct 7 2012 A few light returns on radar are courtesy of a shortwave over the Midwest. However, very few observations have recorded rain other than a sprinkle or two. Have therefore decided to remove mentionable rain from the BWG TAF. As the shortwave moves east today the mid level clouds will move out with mainly cirrus expected through the rest of the TAF period. Winds will be out of the northwest and become light and variable to calm tomorrow night as surface high pressure settles directly over the region. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........13 Short Term.......JSD Long Term........RJS Aviation.........EER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT SUN OCT 7 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 503 AM EDT SUN OCT 7 2012 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW FULL LATITUDE UPR TROF OVER ERN NAMERICA...WITH NW FLOW ALF OVER THE UPR GRT LKS. WITH H85 TEMPS ARND -7C OVER LK SUP /VS WATER TEMPS RANGING FM 6-7C OVER THE W TO 11-12C OVER THE E/...A WEAK SHRTWV MOVING THRU THE UPR LKS...AND ADEQUATE LLVL MSTR PER THE 00Z APX RAOB...SOME LK EFFECT -SHRA MIXED WITH SN CONTINUE OVER MAINLY THE E HALF OF THE LK WHERE INSTABILITY REMAINS GREATEST. PERSISTENT CNVGC SHOWN BY WIND OBS OVER THE E HALF OF THE LAKE ARE ALSO HELPING TO MAINTAIN THE COVERAGE/INTENSITY OF THIS PCPN IN THAT AREA. OVER THE W...MORE ACYC LLVL FLOW ASSOCIATED WITH SFC RDG EXTENDING FM HI CENTER IN THE SCNTRL PLAINS TOWARD THE UPR MIDWEST...COOLER WATERS...AS WELL AS SOMEWHAT DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB ARE CONSPIRING TO LIMIT THE ACTIVITY OVER THAT PART OF THE LAKE. ALTHOUGH DRIER AIR OVER THE NRN PLAINS PER THE 00Z BISMARCK RAOB IS SHIFTING TO THE E IN THE WLY FLOW ON THE NRN FLANK OF THE HI CENTER IN THE SCNTRL PLAINS...THERE IS A GOOD DEAL OF MID/HI CLD EXTENDING FM ARND LK WINNIPEG INTO THE NRN PLAINS ASSOCIATED WITH ISENTROPIC ASCENT ON THE 290-295K SFCS /H7-575/. TODAY...SHORT TERM MODELS ARE IN GOOD AGREEMENT SHOWING LARGER SCALE FLOW OVER THE ENTIRE CWA SHIFTING TO THE W AS HI PRES OVER THE SCNTRL PLAINS SHIFTS TOWARD THE OH RIVER VALLEY...WHICH SHOULD WEAKEN THE LLVL CNVGC NOW PRESENT OVER THE E HALF AND ADVECT WARMER H85 TEMPS/DRIER LLVL AIR TO THE W OVER THE CWA. THESE TRENDS WL TEND TO STEADILY WEAKEN THE ONGOING LK EFFECT PCPN NOW IMPACTING MAINLY THE E HALF OF THE CWA. THE ARRIVAL OF THE DRIER AIR WL ALSO RESULT IN MORE SUNSHINE...WHICH WL BE DIMMED AT TIMES BY THE BKN HIER CLDS DRIFTING INTO THE AREA FM THE NW. MIXING TO H8 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS MAINLY 45-50...EXCEPT IN THE LO 50S WHERE THE INCRSG W WIND DOWNSLOPES OVER THE CENTRAL. SUN NGT...AS NEXT SHRTWV/SFC LO DIGS SEWD THRU SCNTRL CANADA TO NEAR LK WINNIPEG AND SFC HI PRES SHIFTS INTO THE OH RIVER VALLEY BY 12Z...A STRENGTHENING WSW FLOW WL DVLP OVER THE UPR LKS WITH H925 WINDS INCRSG UP TO 25-35 KTS BY 12Z MON. ALTHOUGH SOME MID/HI CLDS ASSOCIATED WITH THE ISENTROPIC ASCENT ON THE 290K SFC WL BE OVER THE UPR LKS...THESE CLDS WL BE RATHER THIN. PWATS AS LO AS 0.25-0.30 INCH INDICATE TEMPS WL STILL FALL FAIRLY SHARPLY OVER THOSE INTERIOR LOCATIONS ESPECIALLY OVER THE SCNTRL THAT CAN DECOUPLE BEFORE THE H925 FLOW STRENGTHENS TOO MUCH OVERNGT. LOCATIONS NEAR LK SUP SHOULD BE WARMEST WITH DOWNSLOPE FLOW. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 503 AM EDT SUN OCT 7 2012 BY MONDAY MORNING THE UPPER GREAT LAKES WILL BE COMPLETELY WITHIN A LARGE 500MB TROUGH THAT WILL ENCOMPASS ALL BUT THE FAR SW CORNER OF THE NATION...EXTENDING FROM THE MAIN LOW OVER N CANADA THROUGH HUDSON BAY. FCST MODELS AGREE WITH THE ENHANCEMENT IN THE MAIN THROUGH SET UP FROM S HUDSON BAY THROUGH CENTRAL SASKATCHEWAN BY MONDAY AFTERNOON...SHIFTING TO CENTRAL MN BY DAYBREAK TUESDAY...AND SLOWLY ACROSS LAKE SUPERIOR/UPPER MI TUESDAY. THE APEX OF THE TROUGH SHOULD BE ACROSS THE CENTER OF THE CWA BY AT 12Z WEDNESDAY...BEFORE PUSHING TO THE LOWER GREAT LAKES DURING THE DAY. THE PROGRESSIVELY S SINKING /RUN TO RUN COMPARISON OVER THE PAST COUPLE OF DAYS/ SFC LOW OVER S MANITOBA AND ND MONDAY MORNING WILL RESULT IN INCREASED SW WINDS ACROSS THE UPPER GREAT LAKES. THE TRACK OF THE SFC LOW IS STILL IN QUESTION...WITH THE 06/18Z RUN OF THE GFS AROUND 6HRS FASTER THAN THE NAM/ECMWF/CANADIAN SOLUTIONS. THE 07/00Z RUN OF THE GFS IS MUCH FARTHER TO THE N...BUT STILL TRACKING A BIT FAST. THE TRACK WILL LIKELY BRING THE SFC LOW OVER W-CENTRAL LAKE SUPERIOR BY 06Z TUESDAY...BEFORE SLIDING NE TO JAMES BAY BY 00Z WEDNESDAY. GIVEN THIS TRACK...THE STRONGEST WINDS WILL LIKELY BE AHEAD OF THE SYSTEM /OUT OF THE SW MONDAY THROUGH MONDAY EVENING/. TEMPERATURE WISE...INCREASED DOWNSLOPE S FLOW WILL BE COUNTERACTED SLIGHTLY BY ADDITIONAL CLOUD COVER MONDAY AFTERNOON NEAR LAKE SUPERIOR. N/NW FLOW WILL RETURN TUESDAY NIGHT BEHIND THE EXITING SFC LOW. 850MB TEMPS OF -5 TO -8C MAY NOT BE ENOUGH TO CREATE MUCH MORE THAN ENHANCED CLOUD COVER NEAR THE LAKE SUPERIOR SHORELINE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE NUDGING IN FROM THE CENTRAL PLAINS WEDNESDAY SHOULD HELP IN PUSHING MUCH OF THE LOW LEVEL MOISTURE TO OUR EAST. IT WILL NOT BE QUITE THAT SIMPLE THOUGH...WITH NW FLOW ALOFT AND A CONTINUATION OF SMALLER SCALE WAVES BRINGING IN ADDITIONAL MOISTURE. THURSDAY THROUGH FRIDAY... YET ANOTHER WAVE LOOKS TO SLIDE IN FROM THE NW THURSDAY OR THURSDAY NIGHT. THE 06/12Z ECMWF WAS APPROX 12 HRS SLOWER THAN THE 06/18Z RUN OF THE GFS WITH THIS WEAKER TROUGH. THE 07/00Z RUNS HAVE NEARLY CORRECTED THIS ISSUE...WITH ONLY MINOR DIFFERENCES. STILL HAVE W TO NW GALES TO 35KTS POSSIBLE OVER CENTRAL AND E LAKE SUPERIOR THURSDAY AFTERNOON AND EVENING. FRIDAY NIGHT THROUGH SATURDAY... HIGH PRESSURE WILL ATTEMPT TO BUILD IN AT 500MB...WITH LITTLE MORE THAN ZONAL FLOW BEING THE RESULT...AS THE NEXT LOW NEAR THE 4-CORNERS GETS SWEPT UP IN THE MAIN FLOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 123 AM EDT SUN OCT 7 2012 COMBINATION OF WINDS BACKING TO THE WEST AND SLIGHT WARMING ALOFT HAS GENERALLY PUT AN END TO LAKE EFFECT SHOWERS AT SAW/IWD. SOME -SHSN MAY CONTINUE AT CMX FOR THE NEXT COUPLE OF HOURS WITH UPSLOPE W WIND...AND MVFR CONDITIONS ARE POSSIBLE EARLY THIS MORNING. DRIER AIR ADVECTING IN FM THE WEST HAS BROUGHT CIGS ABV VFR AT SAW/IWD AND NOW EXPECT VFR CONDITIONS TO CONTINUE THROUGH TAF FCST PD AT THESE LOCATIONS AND AT CMX ONCE THE -SHSN END BY AROUND SUNRISE. ANOTHER SURFACE TROUGH WILL APPROACH UPPER MICHIGAN SUNDAY...LEADING TO INCREASING SWRLY WINDS AND MID- HIGH CLOUDS DURING THE MORNING HOURS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 503 AM EDT SUN OCT 7 2012 AS A HI PRES RIDGE BUILDS TOWARD THE OHIO RIVER VALLEY THRU TONIGHT AND LO PRES MOVES SE THRU CANADA TOWARD MINNESOTA...EXPECT A STRENGTHENING W WIND OVER LAKE SUPERIOR. AS IS TYPICAL FOR THIS FLOW...THE STRONGEST WINDS UP TO 30 KTS ARE MOST LIKELY IN THE AREA BETWEEN THE KEWEENAW AND ISLE ROYALE...WHERE SOME GALE FORCE GUSTS TO 35 KTS ARE POSSIBLE LATER TODAY. LOW PRESSURE NEARING FROM SOUTH CENTRAL CANADA WILL RESULT IN INCREASING SOUTHWESTERLY WINDS MONDAY /WITH S GALES TO 35KTS OVER PORTIONS OF E LAKE SUPERIOR MONDAY INTO MONDAY EVENING/. EXPECT THE LOW TO TRACK FROM ND AND SOUTHERN MANITOBA TO W LS BY LATE MONDAY AFTERNOON INTO MONDAY EVENING. THE LOW WILL PUSH NE TUESDAY...AS ANOTHER DRYING HIGH PRESSURE SYSTEM ATTEMPTS TO BUILD IN FROM THE CENTRAL PLAINS. GUSTS WILL DIMINISH TO 20-25KTS TUESDAY NIGHT. YET ANOTHER LOW SHOULD SKIRT ACROSS OR JUST NORTH OF LAKE SUPERIOR WEDNESDAY NIGHT...WITH WINDS BRIEFLY INCREASING WITH GUSTS NEARING 30KTS AGAIN WEDNESDAY OUT OF THE NW. HIGH PRESSURE SHOULD FINALLY WIN OUT TOWARD THE END OF THE WORK WEEK...WITH ANOTHER ROUND OF WEST TO NORTHWEST GALES TO 35KTS POSSIBLE THURSDAY AFTERNOON AND EVENING...IN BETWEEN NEARING HIGH PRESSURE TO OUR W AND EXITING LOW PRESSURE TO THE E. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR LSZ267. LAKE MICHIGAN... GALE WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING FOR LMZ248-250. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...VOSS MARINE...KC/KF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
527 AM EDT SUN OCT 7 2012 .SYNOPSIS... LAKE EFFECT RAIN SHOWERS WILL BE POSSIBLE EARLY THIS MORNING ACROSS CENTRAL NEW YORK...OTHERWISE DRY WEATHER IS EXPECTED THROUGH EARLY AFTERNOON. RAIN WILL OVERSPREAD THE AREA BY LATE TODAY BEFORE ENDING EARLY TONIGHT. OUR SKY WILL CLEAR OUT TONIGHT AND THIS MAY ALLOW FOR SOME AREAS OF FROST TO FORM BY EARLY MONDAY MORNING. MOSTLY DRY WEATHER IS EXPECTED MONDAY AND TUESDAY BEFORE OUR NEXT SHOT AT WIDESPREAD RAIN COMES WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... 430 AM UPDATE... TODAY....A BAND OF LAKE EFFECT RAIN CONTINUES ACROSS CENTRAL OSWEGO COUNTY AND NORTHERN ONEIDA COUNTY. THE BAND HAS ACTUALLY SHOWN SOME SIGNS OF BECOMING MORE HEALTHY AND HAS PENETRATED FARTHER INLAND IN JUST THE LAST HOUR. HIGHER RESOLUTION MODELS SUCH AS THE HRRR AND THE 4KM NAM WHICH WERE DOING WELL WITH THE PLACEMENT OF THE BAND LATE LAST NIGHT...ARE MUCH TOO WEAK AND TOO FAR SOUTH WITH THE BAND AS OF 09Z. BASED ON THIS CONTINUED TO KEEP HIGH CHANCE POPS ACROSS NORTHERN ONEIDA COUNTY THROUGH 12Z...BEFORE GRADUALLY SHOWING A WEAKENING TREND AS BOUNDARY LAYER WINDS DIMINISH (BAND RETREATS TOWARD LAKE) AND THE FLOW TURNS MORE INTO THE SOUTHWEST. EXPECT ACTIVITY TO DIE DOWN COMPLETELY IN OUR AREA BY 15Z. MEANWHILE FOR THE REST OF US INCREASING HIGH CLOUDS NOW ARE MORE OF A BARK THEN A BITE FOR OUR AREA WITH A UPPER LEVEL JET MOVING OVERHEAD NOW...BUT THE BEST LIFT BEING OFF TO OUR SOUTH AND EAST. KEPT SLIGHT CHANCE POPS IN FOR THE FAR SE CWA IN THE 15Z - 18Z TIME FRAME AS MOST OF THE MODEL GUIDANCE BRINGS POPS INTO INTO EASTERN PA AND NORTHERN NJ...BUT STAYING SOUTH OF THE REGION. A MUCH BETTER SHOT AT RAIN...WIDESPREAD FOR A FEW HOURS...WILL COME WITH A DISTURBANCE IN THE JET STREAM WINDS ALOFT NOW OVER WESTERN IL. RAIN CHANCES WILL INCREASE RAPIDLY BETWEEN 21Z AND 0Z WITH ALL BUT AREAS NORTH OF THE THRUWAY IN LIKELY TO CAT POPS...WITH CHANCE POPS FAR NORTH TONIGHT...RAIN QUICKLY ENDS BY 03Z ACROSS MOST OF THE CWA WITH SOME LAKE EFFECT ACTIVITY (RAIN) POSSIBLE AFTER 06Z UP NORTH. BIGGEST CONCERN HOWEVER IS THE POTENTIAL FOR FROST/FREEZE CONDITIONS. MAV/MET GUIDANCE IS SHOWING 30 AT KELM AND THIS HAS BEEN CONSISTENT OVER THE PAST 24 HOURS. DESPITE SUCH COLD MOS NUMBERS...ELECTED TO HOLD OFF ON ANY ADVISORIES OR WARNINGS AS CONFIDENCE IS NOT QUITE HIGH ENOUGH AT THE MOMENT. CONCERNS INCLUDE THE TIMING ON WHEN WE ACTUALLY CLEAR OUT AND WHETHER OR NOT WE FOG IN OR SEE LOW CLOUDS REDEVELOP GIVEN THE WET GROUND FROM THE RAIN LATER TODAY. WILL LET THE DAY SHIFT REEVALUATE ON ANY HEADLINES AND CONTINUE TO HIGHLIGHT IN THE HWO. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... 430 AM UPDATE... MONDAY/TUESDAY....HIGH PRESSURE MOVIING OUT OF THE OHIO VALLEY SHOULD KEEP MOST OF THIS PERIOD DRY BUT MODEL TRENDS ARE POINTING TO SOME UNCERTAINTY STARTING TUESDAY. ANY LAKE SHOWERS EARLY MONDAY MORNING SHOULD QUICKLY DIMINISH WITH RISING HEIGHTS BY LATE MORNING. FROST/FREEZE CONDITIONS MAY BE POSSIBLE AGAIN MONDAY NIGHT...DEPENDING ON THE AMOUNT OF INCREASING CLOUD COVER WE MAY SEE ESPECIALLY FAR SOUTHEAST. THE MODELS SHOW ANOTHER AREA OF MOISTURE MOVING THROUGH THE MID- ATLANTIC STATES...VERY SIMILAR TO WHAT WILL MISS US EARLY TODAY...LATER MONDAY AND MONDAY NIGHT. AGAIN THE BEST LIFT APPEARS TO BE JUST SOUTH AND EAST OF US AND WILL KEEP OUR AREA DRY THROUGH MONDAY NIGHT. AS THIS MOISTURE SILDES EAST...HIGH PRESSURE MENTIONED ABOVE WILL MOVE OFF THE COAST OF MAINE. THIS WILL HELP TO DEVELOP AN ONSHORE FLOW AND WILL BEGIN TO PUSH MOISTURE BACK TOWARD THE COAST STARTING TUESDAY....ESPECIALLY LATER IN THE DAY. THE GFS AND EURO HINT AT THIS...BUT KEEP PRECIP MAINLY FROM THE HUDSON VALLEY SOUTH AND EAST...WHILE THE NAM IS A BIT FARTHER WEST. FOR NOW WILL PLAY SLIGHT CHANCE POPS TUESDAY FOR LATER IN THE DAY INTO TUESDAY NIGHT GIVEN THE UNCERTAINTY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MEDIUM RANGE MODELS MAINTAIN SOME CONSISTENCY WITH INDICATIONS OF BEST SHOT OF PRECIPITATION ACROSS THE ENTIRE REGION DURING THIS PERIOD TO BE IN THE WEDNESDAY TIME FRAME. THIS IS THEN LIKELY TO BE FOLLOWED BY DEEPENING COLD AIR AND A MAINTAINED PRESENCE OF SHOWER CHANCES TO THE LEE OF LAKE ONTARIO THROUGH THURSDAY WITH IMPROVED WX OVER THE SOUTHERN HALF. ANOTHER WEAK UPPER TROF AND SFC FRONT MAY SPREAD A QUICK SHOT OF SHOWERS INTO THE AREA ON FRIDAY. A FAIRLY LARGE CENTER OF CONTINENTAL POLAR...FALL- LIKE...HIGH PRESSURE WORKS IN FOR AT LEAST THE FIRST HALF OF NEXT WEEKEND. FOLLOWED THE HPC DAY 3-7 GUIDANCE CLOSELY WITH ONLY MINOR LOCAL ADJUSTMENTS TO TEMPERATURES. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... 2 AM UPDATE... GENERALLY VFR THROUGH EARLY THIS AFTERNOON. THE TWO EXCEPTIONS WILL BE EARLY THIS MORNING WITH MVFR CIGS IN LAKE EFFECT CLOUDS POSSIBLE UP NORTH..AND IFR FOG AT ELM. NOW TO THE DETAILS. AN AREA OF LAKE EFFECT RAIN SHOWERS EAST OF LAKE ONTARIO NOW IS IN THE PROCESS OF SHIFTING SOUTH AT THE MOMENT. ALTHOUGH NOTHING MORE THAN A LIGHT SPRINKLE IS EXPECTED AT KSYR...MVFR CIGS WILL BE POSSIBLE BETWEEN 07Z AND 11Z AS THIS BAND MOVES IN. ELM FCST ALSO DIFFICULT...WITH LCL FOG CHECKLIST AND MOS GUIDANCE INDICATING IFR ARND DAYBREAK. IT APPEARS THE LAKE CLOUDS WILL REMAIN WEST OF THE TERMINAL...WHICH HAS ALREADY ALLOWED TEMPS TO DROP INTO THE UPPER 30S OR CLOSE TO THE CROSSOVER TEMP FROM THIS AFTERNOON. WITH THAT SAID UPR DECK MOVG IN FROM THE SOUTHWEST NOW...SO THIS IS NOT A CONFIDENT FCST. WE DECIDED TO HEDGE A BIT AND GO WITH BRIEF IFR DUE TO BR TWDS DAYBREAK. IF MORE CLEARING OCCURS...THEN POTNL WILL EXIST FOR LIFR AT ELM. LATER THIS AFTERNOON...-SHRA WILL SPREAD ACRS THE RGN. WE`VE INDICATED MVFR WITH THIS PCPN AT ALL SITES XCPT SYR/RME WHERE PROB30`S WERE USED BY EARLY TONIGHT. BEST CHC FOR RESTRICTIONS ON SUNDAY AFTN WILL BE AFTER 22Z. NW WINDS OPVERNIGHT 5 KTS OR LESS...THEN SW FLOW LATER TODAY 5-10 KTS BECMG NWLY ACRS CNTRL NY LATE AFTERNOON. OUTLOOK... SUN NIGHT...BECOMING VFR MOST AREAS. AREAS OF FOG AND RESTRICTIONS POSSIBLE...ESPLY KELM. MON TO TUE...VFR. WED...VFR/MVFR. SOME SHOWERS. THU...VFR. SOME LAKE EFFECT RAIN SHOWERS NORTH. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...HEDEN NEAR TERM...HEDEN SHORT TERM...HEDEN LONG TERM...JAB AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BUFFALO NY
145 AM EDT SUN OCT 7 2012 .SYNOPSIS... A WESTERLY FLOW OF CHILLY AIR WILL CONTINUE LAKE EFFECT RAIN SHOWERS EAST OF LAKE ONTARIO TONIGHT WITH THE REST OF THE AREA PARTLY TO MOSTLY CLOUDY. ANOTHER WEAK WAVE OF LOW PRESSURE WILL BRING SOME LIGHT RAIN TO MUCH OF THE REGION SUNDAY ALONG WITH MORE COOL TEMPERATURES. SKIES WILL BEGIN TO CLEAR SUNDAY NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION...ALTHOUGH A FEW LAKE EFFECT SHOWERS MAY LINGER EAST OF THE LAKES. DRY WEATHER WILL RETURN FOR MONDAY AND TUESDAY AS HIGH PRESSURE REMAINS IN PLACE. && .NEAR TERM /THROUGH TODAY/... LAKE EFFECT RAIN ONGOING EAST OF LAKE ONTARIO LATE THIS EVENING. OFF LAKE ONTARIO... THIS BAND CONTINUES TO REMAIN FAIRLY WELL ORGANIZED. KTYX RADAR SHOWING A NEARLY CONTINUOUS LINE OF PRECIP EAST-SOUTHEAST OF LAKE ONTARIO. LIGHT TO OCCASIONALLY MODERATE RAINFALL IS ONGOING ACROSS NORTHERN OSWEGO AND SOUTHERN LEWIS COUNTIES. JEFFERSON AND NORTHERN LEWIS REMAIN DRY NORTH OF THE BAND. WITH THIS BAND LOCATED FURTHER AWAY FROM THE SURFACE RIDGING ACROSS WNY IT WILL LIKELY CONTINUE TO STAY ORGANIZED WELL INTO THE OVERNIGHT HOURS. 00Z NAM BUFKIT INDICATED STILL CLOSE TO 10KFT FOR LAKE EL`S AND 400 J/KG OF LAKE INDUCED CAPE. STILL EXPECT THE BAND FOR RAIN TO CONTINUE TO MOVE SOUTHWARD OVER THE NEXT FEW HOURS. THE LATEST HRRR AND LOCAL WRF MODELS ARE STILL IN AGREEMENT WITH THIS IDEA BUT ARE VERIFYING A LITTLE TO FAR SOUTH COMPARED TO CURRENT RADAR. THE BAND WILL EVENTUALLY LIE PARALLEL WITH THE SOUTHEASTERN SHORELINE OF LAKE ONTARIO LATE TONIGHT WITH MOST OF THE RAINFALL OCCURRING ACROSS OSWEGO COUNTY WITH PORTIONS OF NORTHERN CAYUGA AND NORTHEASTERN WAYNE COUNTIES ALSO CATCHING SOME LIGHT RAIN. LATE TONIGHT INTO SUNDAY MORNING AS FLOW BEGINS TO WEAKEN...LAND BREEZE CONVERGENCE IS FORECAST TO INCREASE ALONG THE SOUTH SHORE OF THE LAKE...WHICH MAY PRODUCE ANOTHER PERIOD OF MORE ORGANIZED LAKE EFFECT AT THE SOUTHEAST CORNER OF THE LAKE. BY THIS TIME THE FLOW WILL BE MUCH WEAKER...SO THE BAND SHOULD TEND TO HUG THE LAKESHORE MORE AND NOT EXTEND VERY FAR INLAND. FINALLY BY MIDDAY SUNDAY THE BOUNDARY LAYER FLOW BECOMES LIGHT ENOUGH TO ALLOW THE BAND TO TEA KETTLE AND RETRACT BACK OUT OVER THE LAKE. INSTABILITY IS A LITTLE GREATER OFF LAKE ONTARIO...AND THE BAND MAY LAST LONGER...SO EXPECT RAINFALL POTENTIAL OF A QUARTER TO HALF INCH HERE...WITH THE GREATEST AMOUNTS ACROSS CENTRAL AND SOUTHERN OSWEGO COUNTY. OFF LAKE ERIE... THE BAND EAST OF THE LAKE HAS BROKEN APART. 850 MB TEMPS ARE PLENTY COLD ENOUGH (-2C OFF THE 00Z KBUF SOUNDING) BUT SURFACE RIDGING HAS BUILT ACROSS MUCH OF WESTERN NY WITH A STRONG SURFACE HIGH CENTERED OVER THE CENTRAL PLAINS. THIS SURFACE RIDGING HAS LOWERED EQUILIBRIUM LEVELS DOWN TO AROUND 7000 FT WHICH IS MUCH TOO SHALLOW TO SUPPORT AND RAIN IN ADDITION TO THE SURFACE RIDGING IN PLACE. SUNDAY MORNING THERE MAY BE A BRIEF RESURGENCE OF LAKE EFFECT ORGANIZATION AS BOUNDARY LAYER FLOW BECOMES A LITTLE MORE WESTERLY. THIS WILL BE SHORT LIVED HOWEVER AS LOW LEVEL FLOW BECOMES VERY LIGHT BY LATE MORNING...WITH ANY REMAINING LAKE EFFECT TENDING TO TEA KETTLE OUT OVER THE LAKE AND NOT EXTEND INLAND. OUTSIDE OF THE LAKE EFFECT...MOST LOCATIONS WILL SEE PARTLY TO MOSTLY CLOUDY SKIES. LATEST IR IMAGERY SHOWS LAKE EFFECT CLOUDS OVER MUCH OF WNY AND WITHIN THE BAND EAST OF LAKE ONTARIO. ONLY CLEAR SPOTS AT 03Z WERE ACROSS CNY. MID LEVEL CLOUDS CAN ALSO BE SEEN ON IR STREAMING NORTHEAST ACROSS WESTERN PA. THESE WILL INCREASE IN COVERAGE ACROSS WESTERN NY AHEAD OF A DEVELOPING SURFACE WAVE. SUNDAY...FOLLOWING ANY LINGERING LAKE EFFECT IN THE MORNING...OUR ATTENTION TURNS BACK TO THE SYNOPTIC SCALE. LATEST SHORT TERM MODEL GUIDANCE SWINGS A STRONG SHORTWAVE THROUGH THE MEAN LONGWAVE TROUGH POSITION...CROSSING THE OHIO VALLEY AND PENNSYLVANIA DURING THE AFTERNOON. THIS WILL INTERACT WITH A FRONTAL ZONE TO OUR SOUTH AND PRODUCE A BAROCLINIC LEAF...WHICH WILL ACT TO INCREASE DIFFERENTIAL THERMAL ADVECTION AND ISENTROPIC UPGLIDE ACROSS THE LOWER LAKES. THIS WILL BRING THICKENING AND LOWERING CLOUD COVER DURING THE DAY WITH A MORE WIDESPREAD LIGHT RAIN DEVELOPING BY MIDDAY OR EARLY AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN TIER AND FINGER LAKES WHERE UP TO A QUARTER INCH MAY FALL. FARTHER NORTH...EXPECT THE NORTHERN EDGE OF THE RAIN SHIELD TO CLIP THE NIAGARA FRONTIER EAST TO ROCHESTER AND THE TUG HILL REGION WITH A LITTLE LIGHT RAIN IN THE AFTERNOON. THE THICKENING CLOUD COVER AND DEVELOPING RAIN WILL BRING ANOTHER CHILLY DAY...WITH THE LOWER ELEVATIONS ONLY TOPPING OUT IN THE LOWER 50S AT BEST...WITH MID TO UPPER 40S ACROSS HIGHER TERRAIN. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... THE MAIN CONCERN FOR THE SUNDAY NIGHT THROUGH TUESDAY NIGHT PERIOD IS THE POTENTIAL OF FROST...OR A WIDESPREAD FREEZE. THIS WOULD BE A GOOD TIME TO ISSUE A FREEZE WATCH FOR SUNDAY NIGHT IF CONFIDENCE WAS HIGH ENOUGH...BUT THERE IS TOO MUCH UNCERTAINTY ABOUT CLOUD COVER AND RESULTING LOW TEMPERATURES AT THIS TIME. A SHORTWAVE CURRENTLY MOVING INTO NE WILL BE IN THE PROCESS OF MOVING THROUGH THE LOWER GREAT LAKES REGION BY SUNDAY AFTERNOON AND EVENING. RAIN ACCOMPANYING THIS SYSTEM WILL MOST LIKELY AFFECT /AT LEAST/ THE SOUTHERN TIER AND PA BEFORE MOVING EAST DURING SUNDAY NIGHT AS THE SURFACE BASED COASTAL LOW NEAR DELMARVA MOVES FURTHER OFFSHORE. THE END RESULT TOWARD MONDAY MORNING WILL BE CLOUDS OVERHEAD MOVING OFF TO THE EAST...WITH A GOOD CHANCE FOR HIGH CLOUD COVER AT LEAST OVER THE EASTERN LAKE ONTARIO REGION. IN ADDITION...THERE SHOULD BE SOME ONGOING LAKE EFFECT RAIN SHOWERS EAST OF THE LAKES OVERNIGHT...WITH CLOUDS SPREADING INTO THE HIGHER TERRAIN EAST OF LAKE ONTARIO AND INTO THE SOUTHERN TIER...THE EXACT LOCATION THAT WOULD NORMALLY BE THE COLDEST PLACES IN WESTERN NY. A FREEZE IS POSSIBLE ON THE FRINGES OF ANY LAKE BANDS AND/OR HIGHER CLOUD COVER...BUT AT THIS TIME IT IS TOO UNCERTAIN AS TO HOW WIDESPREAD THE CLOUD COVER WILL BE. WILL THEREFORE ADD IN SOME FROST INTO THE FORECAST FOR AREAS OUTSIDE OF ANTICIPATED THICKER CLOUD COVER...BUT KEEP TEMPERATURES ABOVE THE FREEZING MARK FOR NOW. ON MONDAY ANY LAKE EFFECT SHOULD QUICKLY END DURING THE MORNING WITH HIGH PRESSURE MOVING INTO THE NORTHEAST. MONDAY NIGHT WILL FEATURE MOSTLY CLEAR SKIES...SO ALTHOUGH TEMPERATURES ALOFT WILL WARM A BIT OVER 24 HOURS...THERE WILL ONCE AGAIN BE A LOW CHANCE FOR SOME FROST OR FREEZING CONDITIONS DUE TO RADIATIONAL COOLING. WILL HAVE A SLIGHTLY LARGER AREA COVERED BY FROST FOR LATE MONDAY NIGHT IN THE TRADITIONAL INLAND LOCATIONS...PRIMARILY THE SOUTHERN TIER AND WELL EAST OF LAKE ONTARIO. QUIET WEATHER IS EXPECTED FOR TUESDAY WITH A CONTINUED WARMING TREND...WITH MAX TEMPERATURES APPROACHING NORMAL VALUES FOR THIS TIME OF YEAR. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE REX BLOCK IN PLACE OVER THE EASTERN PACIFIC WILL REMAIN IN PLACE OR V-E-R-Y SLOWLY MOVE INTO THE WESTERN US THE COURSE OF NEXT WEEK. THEREFORE WE NEED TO LOOK ABOVE BC...NEAR THE TOP OF THE RIDGE FOR THE NEXT FEATURE OF INTEREST. MEDIUM RANGE GUIDANCE HAS BEEN VERY CONSISTENT BRING THE NEXT FEATURE DOWN THROUGH ALBERTA AND SASKATCHEWAN EARLY NEXT WEEK...WITH A SURFACE LOW REMAINING IN CA AND PIVOTING AROUND HUDSON BAY WHILE AN ASSOCIATED COLD FRONT SWEEPS ACROSS THE GREAT LAKES REGION AND ACROSS NYS ON WEDNESDAY. THERE IS SOME UNCERTAINTY AS TO TIMING WITH THE FRONT/PRECIPITATION...WITH RAIN POSSIBLE EITHER WEDNESDAY OR WEDNESDAY NIGHT. WILL KEEP FORECAST GENERALLY UNCHANGED FOR NOW WITH LIKELY RAIN IN THE WEST IN THE AFTERNOON. EXPECT A FAIRLY STRONG RIDGE AFTER THIS FOR THURSDAY WITH DRY WEATHER. THEN ANOTHER FRONT DROPS ACROSS THE REGION DURING THE END OF NEXT WEEK FOR ANOTHER CHANCE OF RAIN. TEMPERATURES DROP QUITE A BIT BEHIND THIS NEXT FRONTAL PASSAGE...WITH 850MB TEMPERATURES DOWN TO -7C EAST OF LAKE ONTARIO. HOWEVER...A FAIRLY STRONG RIDGE WILL ALSO BE IN PLACE BY THE WEEKEND. RIGHT NOW LAKE EFFECT POSSIBILITIES LOOK MINIMAL WITH A LOW LEVEL DRY AIRMASS ACROSS THE LOWER GREAT LAKES REGION. ALTHOUGH THE CURRENT CONCERN FOR A FROST/FREEZE IS FOR SUNDAY OR SUNDAY NIGHT...A BIGGER CONCERN MAY BE NEXT WEEKEND. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... LAKE EFFECT RAIN SHOWERS WILL ORGANIZE EAST OF BOTH LAKE ERIE AND LAKE ONTARIO OVERNIGHT. THE RAIN BANDS WILL PRIMARILY IMPACT AREAS BETWEEN KROC AND KART OFF LAKE ONTARIO...FOCUSING ON KFZY AND KSYR. KJHW COULD SEE SOME OF THIS ACTIVITY TOWARD 12Z SUNDAY MORNING. OCCASIONAL MVFR CIGS AND VSBYS ALSO POSSIBLE IN THE LAKE EFFECT. OUTSIDE OF THESE AREAS...VFR CIGS ARE EXPECTED. ON SUNDAY LAKE EFFECT RAIN SHOWERS WILL LINGER THROUGH THE MORNING EAST OF THE LAKES WITH AREAS OF MVFR AND LOCAL IFR. BY AFTERNOON A WEAK WAVE OF LOW PRESSURE WILL PASS BY JUST TO THE SOUTH OF THE REGION. THIS MAY PRODUCE A LITTLE MORE WIDESPREAD LIGHT RAIN...WITH ASSOCIATED MVFR AND LOCAL IFR CONDITIONS ESPECIALLY ACROSS HIGHER TERRAIN. OUTLOOK... MONDAY AND TUESDAY...VFR. WEDNESDAY...AREAS OF MVFR WITH SHOWERS LIKELY. THURSDAY...MAINLY VFR. && .MARINE... WINDS DIMINISHING STEADILY OVERNIGHT AS THE PRESSURE GRADIENT RELAXES ACROSS THE AREA. A SMALL CRAFT ADVISORY REMAINS THROUGH SUNDAY MORNING FOR THE EAST END OF LAKE ONTARIO AS OBSERVATIONS THERE STILL SHOWING 20 TO 25 KT WINDS. A WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE FOR THE REST OF SUNDAY WITH MUCH LIGHTER WINDS...AND THE LIGHT WINDS WILL LAST INTO MONDAY AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE LOWER LAKES. WATERSPOUTS WILL BECOME MORE LIKELY THROUGH SUNDAY MORNING OFF LAKE ONTARIO IN AND NEAR BANDS OF LAKE EFFECT SHOWERS AND CLOUDS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR LOZ043>045. && $$ SYNOPSIS...HITCHCOCK/SMITH NEAR TERM...SMITH SHORT TERM...ZAFF LONG TERM...ZAFF AVIATION...SMITH/TMA MARINE...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT SUN OCT 7 2012 .SYNOPSIS... A COLD FRONT OVER THE AREA WILL MOVE SOUTHEAST TO COASTAL SECTIONS THIS MORNING. THE FRONT WILL BRIEFLY STALL OVER THE COASTAL AREAS TODAY... BEFORE SHIFTING OFFSHORE THIS EVENING. THICK CLOUD COVER AND A CHILLY AIR MASS WILL HOLD OVER THE REGION THROUGH MONDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 300 AM SUNDAY... EARLY MORNING... THE SURFACE COLD FRONT HAS PUSH SOUTH THROUGH THE AREA SINCE LAST EVENING...NOW STRETCHING FROM KGSP TO KMEB TO KPGV. A PATCH OF SHOWERS MOVING NORTHEAST BETWEEN KGSO AND KRDU IS BEING AIDED BY A WEAK DISTURBANCE LOFT IN WATER VAPOR AND INCREASING ISENTROPIC ASCENT. THE 00Z KGSO RAOB SHOWERS ENOUGH INSTABILITY ABOVE THE STRENGTHENING COLD DOME TO SUPPORT AT LEAST A FEW SPORADIC LIGHTNING STRIKES THROUGH EARLY MORNING. THE HEAVIER SHOWERS A PRODUCING BETWEEN ONE TO TWO TENTHS OF AN INCH OF RAINFALL. BASED ON RAP ISENTROPIC FIELDS AND HRRR SIMULATED REFLECTIVITY...EXPECT THESE SHOWERS TO CONTINUE MOVING OFF TO THE NORTHEAST AND OUT OF THE NORTHERN PIEDMONT/COASTAL PLAIN BY 10Z. TODAY... A SHORTWAVE CURRENTLY APPROACHING THE MID MS VALLEY REGION WILL SWING ACROSS THE OH VALLEY REGION THIS AFTERNOON..WITH PRECIP SPREADING EAST AND EXPANDING ALONG THE 850MB FRONT THAT HAS STALLED FROM THE LOWER TN VALLEY TO THE MID ATLANTIC STATES. WHILE THE FLOW AHEAD OF THE SHORTWAVE WILL STRENGTHEN THIS AFTERNOON...WINDS IN THE 295-305K LAYER STAY RELATIVELY PARALLEL TO FRONTAL ZONE AND CROSS-SECTIONS SHOW MUCH DEEPER MOISTURE ALONG AND WEST OF THE MOUNTAINS. THUS...WHILE OVERCAST SKIES WILL DEVELOP THIS MORNING DUE TO MOISTENING AT THE TOP OF THE STABLE LAYER...PRECIP AMOUNTS SHOULD BE RELATIVELY LIGHT..WITH MODELS NOW ONLY SHOWING A TENTH OF AN INCH OR LESS IN THE NORTHWEST PIEDMONT. TO THE SOUTH AND EAST...THE COLD FRONT WILL STALL ACROSS SC AND SOUTHEAST NC THIS MORNING. A WEAK WAVE OF LOW PRESSURE IS FORECAST TO MOVE FROM CENTRAL NC TOWARD THE OBX THIS AFTERNOON...WHICH SHOULD HELP TRIGGER SOME SHOWERS AND STORMS IN THE VICINITY OF THE FRONTAL ZONE. FORECAST SOUNDINGS AT KFAY LOOK MUCH TOO STABLE FOR ANY NEAR SURFACE BASED CONVECTION...BUT MUCAPE FORECASTS SHOW AROUND 400-600 J/KG JUST TO THE NORTH OF THE FRONT...SO AN ISOLATED AND ELEVATED STORM COULD BE POSSIBLE OVER THE SOUTHEAST CWA. HOWEVER...THE COLD FRONT IS FORECAST TO SURGE FURTHER SOUTH AND EAST AFTER 18Z (IN THE WAKE OF THE SURFACE WAVE)...WITH THE POTENTIAL FOR AN THUNDER BECOMING LESS LIKELY WITH TIME. THE POP FORECAST WILL SHOW A STRONG GRADIENT FROM 80 IN THE NORTHWEST TO 25 IN THE SOUTHEAST. THE RISE IN TEMPS TODAY WILL SOMEWHAT DEPEND ON HOW MUCH PRECIP FALLS...WITH LESS RISE EXPECTED IN THE NORTHWEST PIEDMONT WITH PERIODS OF RAIN EXPECTED THROUGH THIS AFTERNOON. THINNER MOISTURE PROFILES AND A LITTLE MORE HEATING NEAR THE FRONT MAY ALLOW FOR SOME LOWER 70S IN THE FAR SOUTHEASTERN AREAS. MID 50S TO LOWER 70S ARE EXPECTED WITH A SHARP GRADIENT ACROSS THE PIEDMONT. TONIGHT AND MONDAY... AS HIGH PRESSURE EXPANDS ACROSS THE OHIO VALLEY TONIGHT...COOL AND DRIER LOW LEVEL AIR WILL WORK SOUTH INTO THE AREA WITH DEW POINTS FALLING INTO THE 40S CWA-WIDE. THIS WILL ALLOW FOR A LITTLE MORE COOLING AND LOWS REACHING THE 42-49 RANGE AND NO RAIN OVERNIGHT. ANOTHER SHORTWAVE OVER CO/WY THIS MORNING WILL SWING FURTHER SOUTH TOWARD THE TN VALLEY MONDAY...WITH A LITTLE BETTER RAIN CHANCES OVER ALL OF CENTRAL NC AS THE 850MB DRIFTS EASTWARD AND THE RIGHT ENTRANCE REGION OF THE PERSISTENT UPPER JET TO OUR NORTH SHIFTS OVERHEAD. ISENTROPIC ASCENT...WHILE STRONGER...IS STILL NOT VERY IMPRESSIVE...SO RAINFALL TOTALS MAY AGAIN BE LIGHT. HOWEVER... TEMPS WILL LIKELY NOT RISE MUCH AT ALL ACROSS THE CWA AS A BETTER COLD AIR DAMMING AIRMASS DEVELOPS...WITH MOST GUIDANCE INDICATING LOW TO MID 50S...POSSIBLY 60 IN THE FAR SOUTHEAST. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... AS OF 220 AM SUNDAY... FOR MONDAY NIGHT: PATTERN REMAINS DOMINATED BY FAST MID LEVEL CYCLONIC FLOW... ON THE COLD SIDE OF A SURFACE BOUNDARY... RESULTING IN CHILLY AND HIGHLY UNSETTLED WEATHER. THE PARENT HIGH SUPPORTING THE DAMMING REGIME WILL BE CENTERED OVER THE COAST OF MAINE AND CANADIAN MARITIMES WHILE EXTENDING TO THE SW... THROUGH THE NC FOOTHILLS AND WRN PIEDMONT. MOIST UPGLIDE AT 290K-295K IS NOT PARTICULARLY INTENSE OVER CENTRAL NC BUT THE PRESENCE OF A DEEP NEARLY SATURATED LAYER AT 950 MB TO 750 MB SHOULD MAKE THIS LIFT VERY PRODUCTIVE IN TERMS OF CONDENSATION AND PRECIP... AND THE FAST-MOVING PASSAGE OF A MID LEVEL WAVE THROUGH THE AREA SHOULD FURTHER AUGMENT LIFT. UPPER DIVERGENCE OVER CENTRAL NC... IN THE RIGHT ENTRANCE REGION OF THE 120+ KT UPPER JET CORE OVER AND JUST OFF THE NORTHEAST COAST ON MONDAY... QUICKLY DIMINISHES AS THE JET MOVES AWAY TO THE NE... AND FORECAST SOUNDINGS CONFIRM DRYING ALOFT OVERNIGHT... HOWEVER THE COLUMN WILL REMAIN NEARLY SATURATED BELOW 750 MB WITH LOWERING CEILINGS OVERNIGHT WITHIN THE PERSISTENT DAMMING-INDUCED STABLE LAYER. THE MOIST UPGLIDE LARGELY ENDS AFTER MIDNIGHT... AS THE WINDS ALOFT DECELERATE AND THE MID LEVEL WAVE EXITS ALONG WITH THE UPPER JET-RELATED FORCING FOR ASCENT. EXPECT A GRADUAL LOWERING OF LIGHT RAIN AND DRIZZLE COVERAGE FROM SOUTH TO NORTH THROUGH THE NIGHT... ENDING LAST IN THE FAR NORTHWEST CWA (ROXBORO THROUGH THE TRIAD) WHERE SLOPED ASCENT WILL LINGER ALONG A WEAK 925 MB FRONTAL ZONE. LOW CLOUDS... AREAS OF FOG... AND POCKETS OF DRIZZLE ARE LIKELY TO PERSIST AREAWIDE THROUGH DAYBREAK. TEMPS SHOULD DROP NO MORE THAN 10 DEGREES OR SO FROM THE PRECEDING CHILLY DAYTIME TEMPS... YIELDING LOWS OF 42-49. FOR TUESDAY/TUESDAY NIGHT: THE MID LEVEL CANADIAN VORTEX WOBBLES OVER HUDSON BAY WHILE ITS TRAILING BROAD TROUGHING SHIFTS SLOWLY FROM THE UPPER MIDWEST TOWARD MI WHILE AMPLIFYING. THE STRONG (ROUGHLY 1030 MB) PARENT SURFACE HIGH CENTERED OVER NOVA SCOTIA EARLY TUESDAY CONTINUES MOVING NORTHEAST OVER THE MARITIMES... CAUSING THE TRAILING RIDGE TO LOSE ITS GRIP ON CENTRAL NC AND LEAVE BEHIND A DISCONNECTED WEAK RESIDUAL COOL STABLE POOL. THIS SEPARATION FROM THE SUPPLY OF COOL DRY AIR TO MAINTAIN THE DAMMING AIR MASS WILL ALLOW IT TO BECOME VULNERABLE TO HORIZONTAL DISPERSION AND CONVECTIVE MIXING AS THE DRIER AIR ALOFT ALLOWS STRONG HEATING FROM THE TOP... ALTHOUGH TYPICALLY THIS EROSION PROCESS OFTEN TAKES QUITE A WHILE PARTICULARLY WITH A STABLE LAYER THIS DEEP. WILL BE SLOW TO GET RID OF THE WEDGE-SUPPORTED CLOUDS ON TUESDAY... TRENDING GRADUALLY TO PARTLY CLOUDY LATE IN THE DAY. THE WEAK HIGH WILL DRIFT BACK TOWARD THE SW TO OVER THE INTERIOR SOUTHEAST STATES TUESDAY NIGHT... AND WITH THE RESULTING MODIFICATION OF THE AIR MASS... THICKNESSES WILL START TO REBOUND BUT SHOULD STILL HOLD WELL BELOW NORMAL FOR ANOTHER DAY GIVEN THE DELAYED HEATING. EXPECT MODEST WARMING WITH HIGHS OF 60-68. EXPECT FAIR SKIES TUESDAY NIGHT WITH CONTINUED DRYING ALOFT... ALTHOUGH RECOVERING SURFACE DEW POINTS COMBINED WITH LIGHT WINDS IS LIKELY TO LEAD TO DEVELOPMENT OF GROUND FOG OVERNIGHT. LOWS 47-52. -GIH && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 250 AM SUNDAY... EXPECT GENERALLY DRY WEATHER BUT WITH ROLLER COASTER TEMPS AS A SUCCESSION OF FRONTS DROPS THROUGH THE REGION. FOR WEDNESDAY/WEDNESDAY NIGHT: THE MID LEVEL TROUGH AXIS SWINGS SWIFTLY ENE THROUGH THE GREAT LAKES AND NORTHEAST STATES... DRAGGING A SURFACE COLD FRONT THROUGH CENTRAL NC WEDNESDAY AFTERNOON. GIVEN THAT THE SURFACE HIGH CENTER WILL BE LOCATED TO OUR SOUTH AND SW... THERE WILL BE LITTLE TO NO MOISTURE FLUX AHEAD OF THE FRONT... THUS IT SHOULD COME THROUGH DRY. THICKNESSES ARE PROJECTED TO BE AT OR JUST ABOVE NORMAL WEDNESDAY... TRANSLATING TO HIGHS IN THE MID TO UPPER 70S. YUKON-SOURCE HIGH PRESSURE BUILDING IN BEHIND THE FRONT SHOULD SEND THICKNESSES PLUNGING BACK DOWN BELOW NORMAL... WITH LOWS IN THE MID 40S TO NEAR 50. FOR THURSDAY THROUGH SATURDAY: THE SURFACE HIGH IS EXPECTED TO BUILD OVER NC ON THURSDAY... WITH BROAD/FAST/CYCLONIC MID LEVEL FLOW FROM SW CANADA ACROSS THE NORTHEAST STATES. FAIR AND DRY THURSDAY WITH INITIALLY COOL BUT MODERATING TEMPS. A MINOR WAVE DROPS INTO THE LONGWAVE TROUGH OVER THE GREAT LAKES... AND THIS ACCOMPANYING SURFACE COLD FRONT WILL APPROACH NC FROM THE NNW ON FRIDAY. ONCE AGAIN... VERY LITTLE MOISTURE IS AVAILABLE AHEAD OF AND ALONG THE FRONT AND LIFT WILL BE WEAK... SO EXPECT NO MORE THAN ISOLATED SHOWERS AT BEST. TEMPS SHOULD BOUNCE BACK UP TO NEAR NORMAL AHEAD OF THE FRONT FRIDAY. YET ANOTHER COOL HIGH BUILDS IN BEHIND THE FRONT FROM THE NORTH... ITS CENTER MOVING FROM OVER SW MI TO OFF THE NJ/DELMARVA COAST FROM FRIDAY EVENING THROUGH SATURDAY AS IT RIDGES SOUTHWARD THROUGH CENTRAL NC. EXPECT A SLIGHT COOLDOWN OF AROUND A CATEGORY FOR SATURDAY... WITH CONTINUED DRY WEATHER. -GIH && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 135 AM SUNDAY... SHOWERS CURRENTLY MOVING NORTHEAST THROUGH THE PIEDMONT ARE CAUSING BRIEF MVFR CEILINGS AND WILL MOVE OVER KRDU BY 08Z. THE COLD FRONT THAT HAS BEEN MOVING SOUTH THROUGH THE AREA HAS NOW SETTLED SOUTH OF KFAY...ALTHOUGH THERE IS ENOUGH ELEVATED INSTABILITY NORTH OF THE FRONT FOR A FEW LIGHTNING STRIKES WITH THE HEAVIEST SHOWERS. ELSEWHERE...VFR CONDITIONS ARE CURRENTLY OBSERVED BUT WILL DETERIORATE THIS MORNING AS MOISTURE CONTINUES TO INCREASE ON THE NORTH/COOL SIDE OF OF THE FRONT. FORECAST SOUNDINGS GENERALLY AGREE ON MVFR CEILINGS LOWERING TO AROUND 1500 FT BY MIDDAY WITH THE CHANCE FOR RAIN HIGHEST AT KGSO/KINT. SOME BREAKS OR LIFTING OF CEILINGS AND SCATTERED SHOWERS MAY DEVELOP IN THE VICINITY OF THE FRONT...BUT THE FRONT ITSELF IS EXPECTED TO REMAIN SOUTH AND EAST OF KFAY/KRWI...SUCH THAT THE CONFIDENCE IN SHOWERS OR AN ISOLATED STORM IS TOO LOW FOR MENTION IN THE KFAY TAF. SOME DRYING FROM THE NORTH IS EXPECTED THIS EVENING...MOSTLY AFTER 00Z...AND THUS CEILINGS SHOULD EVENTUALLY SCATTER AND LIFT TO VFR AT MOST SITES PRIOR TO MIDNIGHT. HOWEVER...ANOTHER DISTURBANCE ALOFT IS EXPECTED TO IMPACT THE AREA MONDAY...WITH WIDESPREAD MVFR/IFR CEILINGS TO REDEVELOP. OUTLOOK... LOW CEILINGS WILL LIKELY CONTINUE THROUGH AT LEAST TUESDAY...WITH IMPROVEMENT IN AVIATION CONDITIONS BY THE MIDDLE TO END OF THE WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...BLS SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...BLS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
357 AM EDT SUN OCT 7 2012 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL TRACK ACROSS THE REGION FROM THE WEST AND OVER A LAYER OF COOLER AIR. THIS WILL RESULT IN A WET AND COOL DAY SUNDAY. MORE RAIN AND COOL TEMPERATURES ARE EXPECTED MONDAY AS ANOTHER UPPER LEVEL DISTURBANCE ENTERS FROM THE SOUTHWEST. BY TUESDAY...DRIER CONDITIONS WILL ARRIVE AND CONTINUE INTO THE LATER PART OF THE WEEK UNDER HIGH PRESSURE. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM EDT SUNDAY... WATER VAPOR SATELLITE IMAGERY INDICATES A WEAK SHORTWAVE ACROSS EASTERN KY INTO CENTRAL TN. THIS FEATURE IS IN ADVANCE OF A STRONGER UPPER LEVEL DISTURBANCE LOCATED ACROSS IOWA INTO MO. HRRR AND LOCAL WRF MODELS DEPICT THIS AREA OF RAIN WELL...UNDER THE RR QUAD OF A LIFTING UPPER LEVEL JET. WITH GOOD ISENTROPIC LIFT CONTINUING INTO EARLY AFTERNOON AND THE APPROACH OF MIDWESTERN UPPER LEVEL SHORTWAVE...PRECIP SHOULD EXPAND IN COVERAGE. AS A RESULT...WILL CONTINUE TO CARRY LIKELY POPS INTO THE EARLY AFTERNOON. BEHIND THIS SYSTEM...LOW LEVEL WINDS VEER TO THE NORTHWEST AND ISENTROPIC DOWNGLIDE BEINGS LATE THIS AFTERNOON/EARLY THIS EVENING...WHICH WILL GRADUALLY BRING AN END TO THE PRECIP. CLOUDS...WEAK CAA...AND PRECIP WILL KEEP TEMPERATURES FROM RISING MUCH AT ALL TODAY. IN FACT...TEMPS MAY DROP TODAY. THEREFORE...LEANED TOWARD THE COOLER MAV AND LOCALLY DERIVED MOS GUIDANCE FOR HIGHS TODAY. THE NEXT UPPER LEVEL SYSTEM ZIPPING INTO THE LOWER OHIO VALLEY BY LATE SUNDAY NIGHT/EARLY MONDAY MORNING WILL BACK LOW LEVEL WINDS AND SET UP A BAROCLINIC ZONE ACROSS THE SOUTHERN PORTION OF OUR FORECAST AREA LATE TONIGHT. THIS MAY GENERATE SOME LIGHT PRECIP IN THIS REGION...AND KEPT SMALL POPS HERE LATE TONIGHT. IN THE NORTH...THE THREAT FOR FROST APPEARS LOW WITH A WET GROUND/WARM SOIL TEMPS AND CLOUD COVER. IF ANY CLEARING CAN BE MAINTAINED...SOME PATCHY FROST IN THE DEEP MOUNTAIN VALLEYS FROM BURKES GARDEN INTO SOUTHEAST WV MAY DEVELOP. WITH THE INCREASE IN CLOUDS...USED A MAV/MET MIX FOR LOWS WHICH ARE CLOSE TO OUR LOCALLY DERIVED MOS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AS OF 400 AM EDT SUNDAY... A JET COUPLET PROVIDING DIFFLUENCE ALOFT WILL COMBINE WITH FRONTOGENESIS JUST ABOVE THE GROUND ACROSS SE WEST VA TO GENERATE LIGHT RAIN ON MONDAY MOSTLY BLUE RIDGE AND WEST. ALTHOUGH QPF WILL BE SMALL...POSSIBLY ONLY A FEW HUNDREDTHS...SPOTTY DRIZZLE WILL HELP TO MAKE THIS A DAMP AND COOL DAY. WITH PRECIP AND E TO NE FLOW CONTINUING...CAN`T SEE TEMPS GOING MUCH OF ANYWHERE...AND ALL OF THE GUIDANCE WITH THE EXCEPTION OF THE LOCALLY BIAS CORRECTED ECMWF LOOKS TOO WARM. QUITE POSSIBLE SOME OF THE COOLEST SPOTS DON`T EVEN REACH 45F WITH THE POSSIBILITY THAT MANY PLACES DON`T REACH 50F. CLOUDS BREAKING LATE MONDAY NIGHT SHOULD KEEP TUESDAY MORNING LOW TEMP A FEW WARMER THAN GUIDANCE...AND A RATHER WET AND WARM GROUND WITH TEMPS NOT FALLING INTO THE 30S UNTIL LATE SHOULD PRECLUDE ANY FROST. WITH ABUNDANT LLVL MOISTURE AND EASTERLY COMPONENT CONTINUING BLUE RIDGE AND EAST...HELD ONTO CLOUDS AND WENT WITH MAX T CLOSER TO THE 2M NAM VALUES TUESDAY. WEDGE FIGURES TO BE SLOWER TO LIFT OUT THAN OTHER MODELS DEPICT. THIS COULD BE ONE OF THOSE DAYS WHERE BCB IS WARMER THAN ROA AND LWB IS WARMER THAN DAN/LYH. CLOUDS SHOULD BREAK WEST OF THE BLUE RIDGE WITH MORE WESTERLY COMPONENT TUESDAY. SHOWERS SHOULD CRUMBLE ACROSS WEST VA WITH FRONT THAT APPROACHES ON WEDNESDAY WITH DEEP DOWNSLOPING FLOW AHEAD OF IT. BIG TEMP REBOUND THOUGH BLUE RIDGE AND EAST...EASILY THE BEST DAY OF THE NEXT SEVERAL WITH MAX T ONCE AGAIN IN THE 70S ON WEDNESDAY. A BETTER DRY PUNCH SETS THE STAGE FOR SOME NEAR FREEZING TEMPS PERHAPS THURSDAY MORNING ACROSS SE WEST VA...EXTREME SW VA AND NW NC. && .LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 400 PM EDT SATURDAY... ANOTHER FRONTAL BOUNDARY APPROACHES DURING THE WEEKEND AND ARRIVES EARLY NEXT WEEK...ALLOWING TEMPERATURES TO MODERATE. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... AS OF 130 AM EDT SUNDAY... AN APPROACHING UPPER LEVEL DISTURBANCE WILL ENHANCE THE CHANCES OF RAIN TODAY. IN ADVANCE OF THIS SYSTEM...CEILINGS HAVE BEEN DROPPING INTO THE MVFR CATEGORY...AND EVEN IFR CATEGORY IN SOME MOUNTAIN LOCATIONS IN NORTHWEST NORTH CAROLINA. EXPECT THIS LOWERING TREND TO CONTINUE...ESPECIALLY IN THE MOUNTAINS EARLY THIS MORNING...WITH RAIN DEVELOPING BETWEEN 10-13Z. MVFR TO POCKETS OF IFR CEILINGS WILL BE FOUND THROUGH THE DAY. ONCE THE UPPER LEVEL SYSTEM MOVES EAST AND WEAK LOW LEVEL NORTHWEST FLOW FORMS...EXCEPT A CEILINGS TO RISE THIS EVENING. THESE IMPROVING CONDITIONS WILL ONLY BE TEMPORARY AS ANOTHER UPPER LEVEL SYSTEM MOVING OVER THE REGION MONDAY WILL BRING WIDESPREAD MVFR/IFR CIGS AND LIGHT PRECIPITATION. HIGH PRESSURE BUILDING OVER THE AREA FOR TUESDAY WILL FINALLY BRING VFR CONDITIONS THAT ARE EXPECTED TO LAST THROUGH THURSDAY...ALTHOUGH A PERIOD OF MVFR CIGS POSSIBLE IN THE MTNS WITH A COLD FRONTAL PASSAGE WEDNESDAY. && .EQUIPMENT... THE KFCX DOPPLER RADAR...WHICH SERVES ROANOKE AND THE SURROUNDING AREAS...WILL REMAIN DOWN FOR THE NEXT FEW DAYS AS THE INSTALLATION OF THE NEW DUAL-POL TECHNOLOGY CONTINUES. THE RADAR MAY RETURN TO SERVICE AS EARLY AS THE MIDDLE OF NEXT WEEK. NEIGHBORING DOPPLER RADARS AT STERLING VA (KLWX)...WAKEFIELD VA (KAKQ)...RALEIGH NC (KRAX)...GREENVILLE-SPARTANBURG SC (KGSP)...MORRISTOWN TN (KMRX)...AND CHARLESTON WV (KRLX) WILL CONTINUE TO PROVIDE COVERAGE OVER PARTS OF THE KFCX AREA DURING THIS TIME FRAME. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...KM/PM NEAR TERM...PH SHORT TERM...KM LONG TERM...KK AVIATION...PH EQUIPMENT...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1152 PM CDT SAT OCT 6 2012 .SHORT TERM...TONIGHT THROUGH TUESDAY 252 PM CDT SAT OCT 6 2012 MAIN FORECAST CONCERNS ARE ON FREEZE POTENTIAL TONIGHT...NEAR CRITICAL FIRE WEATHER CONDITIONS SUNDAY AND MONDAY...AND FINALLY PRECIPITATION CHANCES FOR MONDAY NIGHT AND TUESDAY. CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER THE NORTHEAST PACIFIC AND ALONG THE WEST COAST OF THE U.S....WHILE DEEP TROUGHING WAS PRESENT OVER CENTRAL AND EASTERN CANADA SOUTHWARD INTO THE CENTRAL PLAINS AND OHIO RIVER VALLEY. WITHIN THE TROUGHING...A SHORTWAVE TROUGH EXTENDED EAST-WEST ACROSS THE FORECAST AREA AND WEST TOWARDS NEBRASKA. UNDERNEATH THIS SHORTWAVE TROUGH WAS AN AREA OF BROKEN STRATUS ACROSS THE FORECAST AREA TO NEAR DULUTH. MUCH OF THIS STRATUS WAS SITUATED AT 750MB OR BELOW PER 12Z SOUNDINGS FROM INL...MPX AND GRB. THE REASON THE DECK IS NOT A SOLID OVERCAST IS THAT THE SOUNDINGS DO NOT SHOW COMPLETE SATURATION. IN FACT...SOME OF THE STRATUS FORMATION HAS BEEN DUE TO DAYTIME HEATING...NOTED BY HOLES THAT FILLED IN DURING THE MORNING. FARTHER TO THE NORTHWEST ON WATER VAPOR...A SHORTWAVE TROUGH WAS EVIDENT IN SOUTHERN SASKATCHEWAN DROPPING DOWN THE EAST SIDE OF THE NORTHEAST PACIFIC RIDGE. LACK OF LOW LEVEL MOISTURE SEEN ON THE 12Z THE PAS MANITOBA SOUNDING HAS RESULTED IN THE SHORTWAVE JUST PRODUCING A BAND OF MID AND HIGH CLOUDS. AT THE SURFACE...HIGH PRESSURE WAS SITUATED OVER THE CENTRAL PLAINS WITH A RIDGE AXIS EXTENDING NORTHEAST INTO NORTHERN MINNESOTA. 850MB TEMPS CHILLY OVER THE FORECAST AREA...BETWEEN -5 AND -7C PER 12Z RAOBS...OR 2 STANDARD DEVIATIONS BELOW NORMAL. TONIGHT AND SUNDAY...SHORTWAVE TROUGH OVER SOUTHERN SASKATCHEWAN IS PROGGED TO KEEP DROPPING SOUTHEAST THROUGH THE DEEP UPPER TROUGH... CROSSING THE FORECAST AREA SUNDAY AFTERNOON. THIS TROUGH WILL DO A COUPLE OF THINGS. FIRST...THE SURFACE RIDGE AXIS OVER MINNESOTA WILL GET PUSHED DOWN OVER THE FORECAST AREA TONIGHT. AS THE RIDGE AXIS AND THE DRY AIR ASSOCIATED WITH IT MOVE IN...SKIES WILL CLEAR. WINDS SHOULD DECOUPLE AS WELL...EXCLUDING THE HIGHER TERRAIN OF SOUTHEAST MINNESOTA. GIVEN THE COOL DAY TODAY...THE SETUP CERTAINLY FAVORS LOWS DROPPING INTO THE 20S AS HAS BEEN FORECAST THE PAST FEW DAYS. SOME OF THE TYPICAL COLD SPOTS IN WISCONSIN COULD EVEN HIT THE UPPER TEENS. FREEZE WARNINGS THEREFORE STILL LOOK GOOD WITH THIS LIKELY BEING THE END OF THE GROWING SEASON. THE SECOND THING THE SHORTWAVE TROUGH WILL DO IS TO SPREAD THE CIRRUS AND SOME MID CLOUDS SEEN UP IN SOUTH CENTRAL CANADA ACROSS THE FORECAST AREA. REGARDING TEMPERATURES... DOWNSLOPING OF AIR OFF THE ROCKIES AHEAD OF THE SHORTWAVE TROUGH WILL ALLOW A PLUME OF WARMER 925-850MB AIR TO ADVECT INTO THE FORECAST AREA. BY 18Z... 925MB AND 850MB TEMPS RISE TO 2-4C AND -3 TO -5C RESPECTIVELY. COMBINE THESE WITH AN INCREASING SOUTHWEST WIND AS THE SURFACE RIDGE DROPS SOUTH AND HIGHS SHOULD BE ABLE TO REACH INTO THE LOW TO MID 50S. DRY DEWPOINTS IN THE TEENS WILL HELP RELATIVE HUMIDITIES PLUMMET INTO THE 20-30 PERCENT RANGE...RAISING SOME FIRE WEATHER CONCERNS. THESE ARE NOTED IN THE FIRE WEATHER DISCUSSION BELOW. SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO A SHORTWAVE CURRENTLY WELL UP TO THE NORTHWEST...NEAR THE NORTHWEST CORNER OF THE NORTHWEST TERRITORIES. MODELS HAVE BEEN VERY CONSISTENT OF DROPPING THIS SHORTWAVE INTO THE DEEP TROUGH...REACHING SOUTHERN PORTIONS OF SASKATCHEWAN AND MANITOBA BY 12Z MONDAY. AS THE SHORTWAVE DROPS SOUTH...A DEEPENING SURFACE LOW ACCOMPANIES IT...WHICH SHOULD REACH FAR SOUTHERN MANITOBA BY 12Z MONDAY. THIS DEEPENING LOW WILL HELP TO INCREASE THE SOUTHWEST WINDS EVEN MORE OVER THE FORECAST AREA...AND ALSO ENHANCE THE DOWNSLOPE EFFECT OFF THE ROCKIES. AS SUCH...925 AND 850MB TEMPS CLIMB TO 6C AND 4C RESPECTIVELY AT 12Z MONDAY. THIS WARM ADVECTION IS LIKELY TO RESULT AN INCREASE OF MID AND HIGH CLOUDS... ESPECIALLY AFTER MIDNIGHT SUNDAY NIGHT AND HEADING INTO THE DAY MONDAY. THESE CLOUDS COMBINED WITH THE WINDS WILL HELP PRODUCE A MUCH WARMER NIGHT...ALBEIT STILL BELOW NORMAL...MAINLY IN THE 30S. AFTER 12Z MONDAY...MODELS DIFFER A BIT ON THE TRACK...DEPTH AND SPEED OF THE SHORTWAVE TROUGH AND SURFACE LOW. OVERALL...THOUGH... THE GENERAL THEME IS FOR THE SHORTWAVE AND SURFACE LOW TO HEAD EAST...LIKELY ALONG THE ONTARIO/MN BORDER. COLD FRONT ASSOCIATED WITH THE LOW STAYS TO OUR WEST...ONLY REACHING ALBERTA LEA BY 00Z. 925MB AND 850MB TEMPS CONTINUE TO WARM AHEAD OF THIS FRONT...TOPPING OUT AT 12-14C AND 6-8C RESPECTIVELY. WITH A TIGHT PRESSURE GRADIENT AND MIXING RESULTING IN BREEZY SOUTHWEST WINDS...ALONG WITH DRY LOW LEVEL AIR...WE SHOULD BE ABLE TO MIX TO NEAR 850MB. ONLY CAVEAT IS THE MID/HIGH CLOUDS...WHICH LOOK TO INCREASE AND THICKEN THROUGH THE DAY. ANY PRECIPITATION WITH THESE CLOUDS SHOULD STAY NORTH OF THE FORECAST AREA PER MODEL CONSENSUS. HIGHS IN THE 60S STILL ARE REASONABLE...PERHAPS GETTING CLOSE TO 70 WEST OF THE MISSISSIPPI RIVER. FIRE WEATHER CONCERNS EXIST AGAIN WITH THE BREEZY SOUTHWEST WINDS...TEMPERATURES AND LOW RELATIVE HUMIDITIES. SEE FIRE WEATHER DISCUSSION BELOW. MONDAY NIGHT AND TUESDAY...MODELS SHOW YET ANOTHER FAIRLY STRONG SHORTWAVE DROPPING DOWN THE EAST SIDE OF THE NORTHEAST PACIFIC RIDGE...DIGGING INTO NORTH DAKOTA BY 12Z TUESDAY AND THEN INTO SOUTHERN MINNESOTA BY 00Z WEDNESDAY. THIS SHORTWAVE SHOULD HELP TO ENHANCE LIFT IN THE WAKE OF THE COLD FRONT...ON TOP OF THE POST-FRONTAL MID LEVEL FRONTOGENESIS THAT WILL ALREADY EXIST. SO ONCE THE COLD FRONT MOVES EAST THROUGH THE FORECAST AREA...WHICH GRADUALLY OCCURS DURING THIS PERIOD UNTIL THIS SHORTWAVE CAN CATCH UP...ANTICIPATE A BAND OF RAIN TO DEVELOP. THIS SIGNAL OF THE BAND OF RAIN CONTINUES TO GET STRONGER...WITH THE 06.12Z GFS...NAM... UKMET...CANADIAN AND ECMWF ALL DEPICTING IT. AS SUCH...HAVE RAISED PRECIPITATION CHANCES UP TO AROUND 40. FURTHER INCREASES WILL LIKELY BE NEEDED IF THIS SIGNAL PERSISTS. PRECIPITABLE WATER VALUES ARE ONLY AROUND 0.75 OF AN INCH...SO MOISTURE IS NOT THAT GREAT...BUT THE FORCING SHOULD BE ABLE TO SQUEEZE OUT SOME LIGHT PRECIPITATION. WITH PLENTY OF CLOUDS MONDAY NIGHT AND THE SLOW COLD FRONTAL PASSAGE...LOWS IN THE 40S SUGGESTED BY MAV/MET GUIDANCE SEEM REASONABLE. 850MB TEMPS DO GRADUALLY FALL DURING THE DAY TUESDAY...BOTTOMING OUT AROUND 0C BY 00Z. NEVERTHELESS...HIGHS SHOULD BE ABLE TO TOP OUT IN THE 50S...COOLEST IN THE NORTHWEST WHICH ENDS UP MOSTLY BEHIND THE FRONT FOR THE ENTIRE DAY. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 252 PM CDT SAT OCT 6 2012 GOOD MODEL AGREEMENT EXISTS BETWEEN THE 06.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ABOUT A PATTERN SHIFT OCCURRING DURING THE LONG TERM FORECAST...WITH THE CURRENT DEEP TROUGH LIFTING OUT ON FRIDAY. WE STILL HAVE ONE MORE POTENT SHORTWAVE TO DEAL WITH DROPPING THE TROUGH PRIOR TO LIFT-OUT...PROGGED TO CROSS LAKE SUPERIOR LATE THURSDAY. AFTER FRIDAY...MODELS SHOW AN UPPER LOW...CURRENTLY JUST OFF THE COAST OF CALIFORNIA...LIFTING OUT OF THE SOUTHWESTERN U.S.. EXACTLY HOW FAST THIS EJECTION OCCURS THE MODELS ARE ALL OVER THE PLACE...WITH THE LATEST 06.12Z GFS THE FASTEST AMONGST ALL MODELS AND PAST 1-2 DAYS OF RUNS OF THE MODEL. THE GFS HAS THIS DEEP LOW LIFTING UP INTO SOUTHERN MINNESOTA BY 00Z SUNDAY. EJECTING UPPER LOWS OUT OF THE SOUTHWESTERN U.S. ARE ALWAYS PROBLEMATIC FOR MODELS...SINCE THEY HINGE ON UPPER TROUGHS CROSSING THE PACIFIC. THEREFORE...HAVE LOW CONFIDENCE ON ANY SOLUTION AT THIS POINT... THOUGH IT WOULD NOT BE SURPRISING IF A SLOWER IDEA ENDS UP PANNING OUT PER MODEL BIASES. IN THE WAKE OF TUESDAYS SHORTWAVE...A RIDGE OF HIGH PRESSURE IS FORECAST TO BUILD IN FOR WEDNESDAY. ANOTHER SHOT OF COOL AIR COMES WITH THIS RIDGE WITH 850MB TEMPS FALLING TO AROUND -4C. THUS... TUESDAY NIGHT AND WEDNESDAY WILL BE COOL...BUT NOT NEARLY AS COLD AS TODAY OR TONIGHT. COULD BE SOME LINGERING PRECIP TUESDAY EVENING IN THE SOUTHEASTERN THIRD OF THE AREA...ASSOCIATED WITH TUESDAYS SHORTWAVE...OTHERWISE EXPECT DRY CONDITIONS. WITH THE THURSDAY SHORTWAVE DROPPING DOWN INTO LAKE SUPERIOR...WE GET ANOTHER COLD FRONT TO MOVE THROUGH THE FORECAST AREA. DUE TO LIMITED SPACING BETWEEN THE CANADIAN RIDGE OF HIGH PRESSURE AND THIS FRONT...NOT ANTICIPATING ANY POST-FRONTAL PRECIPITATION. AHEAD OF THE FRONT...A SURGE OF 4-6C 850MB AIR IS PROGGED TO COME INTO THE AREA ON STRONG SOUTHWEST WINDS. SO WE COULD HAVE ANOTHER NEAR CRITICAL FIRE WEATHER DAY...PARTICULARLY SOUTH OF I-90. ANOTHER COOLER HIGH PRESSURE AREA IS SLATED TO DROP DOWN INTO OUR REGION FOR FRIDAY...WITH 850MB TEMPS DROPPING BACK TO AROUND -4C AT 12Z. FOR FRIDAY NIGHT AND SATURDAY... HAVE FOLLOWED THE CONSENSUS APPROACH AND SPREADING CHANCES OF PRECIPITATION INTO THE AREA FROM THE SOUTHWEST. THESE ARE ALL DUE TO WARM...MOIST AIR ADVECTION OUT OF THE GULF OF MEXICO COMING INTO THE COLDER AIRMASS SITUATED OVER THE FORECAST AREA. MORE REFINEMENT OF THESE CHANCES WILL COME DURING THE NEXT SEVERAL DAYS AS TIMING OF THE UPPER LOW EJECTION BECOMES MORE CERTAIN. SHOULD SEE A GRADUAL WARM UP IN TEMPERATURES TOO WITH THE WARMER AIR ADVECTING INTO THE AREA. HIGHS BY SATURDAY STILL LOOK BELOW NORMAL BUT ONLY 5 OR SO DEGREES...NOT LIKE THE 15-20 AS OF LATE. && .AVIATION...THROUGH 06Z MONDAY 1151 PM CDT SAT OCT 6 2012 INFRARED SATELLITE IMAGERY SHOWS BACK EDGE OF STRATUS DECK FROM NORTHWEST WISCONSIN TO NEAR KAEL. THE BACK EDGE HAS BEEN SLOWLY WORKING ITS WAY SOUTHEAST AND MODELS CONSISTENT IN SHOWING THIS BACK EDGE WILL MAKE IT TO KRST AROUND 07Z AND KLSE BETWEEN 08Z- 09Z. UNTIL THEN CEILINGS WILL RANGE FROM 050-060K FEET. AFTER THAT JUST SOME HIGH CLOUDS ARE EXPECTED WITH VFR CONDITIONS THROUGH THE REMAINDER OF THE TAF PERIOD. && .FIRE WEATHER...SUNDAY INTO MONDAY 252 PM CDT SAT OCT 6 2012 NEAR CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE BOTH SUNDAY AND MONDAY. SETTING THE STAGE FOR THESE CONDITIONS IS THE MODERATE TO EXTREME DROUGHT CONDITIONS IN PLACE ACROSS THE AREA...ALONG WITH A KILLING FREEZE EXPECTED TONIGHT. FOR SUNDAY...SOUTHWEST WINDS ARE EXPECTED TO INCREASE IN THE WAKE OF A RIDGE OF HIGH PRESSURE DROPPING SOUTH ACROSS THE AREA TONIGHT. THESE WINDS SHOULD BE SUSTAINED IN THE 10-15 MPH RANGE WITH GUSTS OF 12-22 MPH...STRONGEST ACROSS SOUTHEAST MINNESOTA. DEWPOINTS ARE LIKELY TO STILL BE LOW...THANKS TO MIXING OF DRY AIR ALOFT AND THE RECENT COLD NIGHT. HOWEVER...LINGERING COLD AIR THAT ONLY SLOWLY MODIFIES WILL ONLY ALLOW HIGH TEMPERATURES TO TOP OUT IN THE LOW TO MID 50S. THESE TEMPERATURES COMBINED WITH THE DEWPOINTS SHOULD PRODUCE MINIMUM RELATIVE HUMIDITIES IN THE 20-30 PERCENT RANGE... LOWEST SOUTH AND WEST OF I-94. THEREFORE...THE MAIN LIMITING FACTORS FOR RED FLAG CONDITIONS WOULD BE THE TEMPERATURES AND WINDS. FOR MONDAY...A STRENGTHENING LOW PRESSURE SYSTEM DROPPING SOUTH OUT OF CENTRAL CANADA INTO NORTHERN MINNESOTA WILL RESULT IN A TIGHTER PRESSURE GRADIENT ACROSS THE AREA. AS SUCH...STRONGER WINDS ARE ANTICIPATED...IN THE 15-25 MPH RANGE WITH GUSTS OF 20-35 MPH. HIGHEST WINDS ARE LIKELY WEST OF THE MISSISSIPPI RIVER. THESE WINDS SHOULD BRING UP A LITTLE MORE MOISTURE...BUT HIGH TEMPERATURES WILL MOSTLY COUNTERACT IT BY JUMPING INTO THE 60S. THEREFORE...MINIMUM RELATIVE HUMIDITIES ARE ONLY SLIGHTLY HIGHER...BETWEEN 25-35 PERCENT...LOWEST ALONG/WEST OF THE MISSISSIPPI RIVER. GIVEN THE SLIGHTLY HIGHER MINIMUM RELATIVE HUMIDITIES...TEMPERATURES STILL SLIGHTLY COOL AND ESPECIALLY POTENTIAL FOR A LOT OF CLOUDS... CONDITIONS AGAIN JUST LOOK NEAR CRITICAL. THE CLOUDS COULD BE QUITE PROBLEMATIC BY KEEPING RELATIVE HUMIDITIES HIGHER THAN EXPECTED. PER COORDINATION WITH AREA FIRE WEATHER AGENCIES...HAVE HELD OFF ON ANY FIRE WEATHER WATCHES AT THIS TIME. LOOKING AHEAD...ANOTHER NEAR CRITICAL FIRE WEATHER DAY COULD OCCUR SOUTH OF I-90 ON THURSDAY...AHEAD OF A CANADIAN COLD FRONT. && .ARX WATCHES/WARNINGS/ADVISORIES... 252 PM CDT SAT OCT 6 2012 WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT SUNDAY FOR WIZ032-033-041- 053>055-061. MN...FREEZE WARNING FROM 1 AM TO 8 AM CDT SUNDAY FOR MNZ079-088-096. IA...FREEZE WARNING FROM 1 AM TO 8 AM CDT SUNDAY FOR IAZ011-030. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...RABERDING FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS DENVER CO
924 AM MDT SUN OCT 7 2012 .UPDATE...PATCHY FOG IN THE LOWER SOUTH PLATTE RIVER VALLEY HAS DISSIPATED. SUNNY SKIES ARE EXPECTED FOR THE REST OF THE DAY WITH ONLY A FEW WISPY CIRRUS. TEMPERATURES ON TRACK TO REACH THE LOWER 50S ON THE PLAINS WITH SLIGHTLY COOLER READINGS OVER THE SNOW COVERED NORTHEAST CORNER. GIVEN THE WIDESPREAD HARD FREEZE LAST NIGHT...WE WILL NO LONGER ISSUE FREEZE WARNINGS AS THE EFFECTIVE GROWING SEASON HAS COME TO AN END. && .AVIATION...NEARLY CLOUD FREE SKIES EXPECTED THROUGH TONIGHT WITH UNLIMITED VISIBILITY. WEAK AND FAIRLY NORMAL DIURNAL WIND PATTERNS EXPECTED PER ONGOING TAFS. && .PREV DISCUSSION... /ISSUED 333 AM MDT SUN OCT 7 2012/ SHORT TERM...NNW FLOW ALOFT WILL BE OVER THE AREA THRU TONIGHT WITH DRY CONDITIONS EXPECTED. MAIN CONCERN FOR THIS MORNING WILL BE FOG POTENTIAL OVER NERN CO. SO FAR THE ONLY PLACE WITH FOG IS OVER THE FAR NERN CORNER WHERE SKIES HAVE BEEN CLEAR OVERNIGHT. CLOSER TO THE FRONT RANGE LOW LVL CLOUDS HAVE REMAINED IN PLACE BUT HAVE BEEN SLOWLY DIMINISHING THE LAST FEW HOURS. AT THIS TIME WILL KEEP AREAS OF FOG OVER THE PLAINS WHERE SKIES HAVE BEEN GENERALLY CLEAR AND ONLY MENTION PATCHY FOG CLOSER TO THE FOOTHILLS. AS FAS AS AFTN HIGHS WILL KEEP HIGHS IN THE LOWER TO MID 50S ACROSS NERN CO FOR THIS AFTN. FOR TONIGHT SHOULD SEE MAINLY CLEAR SKIES. MAY SEE SOME GUSTY WINDS IN THE MTNS AND HIGHER FOOTHILLS LATE TONIGHT AS A WK MTN WAVE DEVELOPS. LONG TERM...NORTHERN COLORADO WILL BE UNDER A MODERATE NORTHWEST FLOW PATTERN THROUGH MIDWEEK WITH A DRY AIRMASS IN PLACE. THERE WILL BE A WEAK TROF WHICH MOVES THROUGH THE NORTHERN PLAINS STATES ON TUESDAY. THERE WILL BE AN ASSOCIATED COLD FRONT WHICH WILL COOL TEMPERATURES ACROSS NORTHEAST COLORADO ON TUESDAY AS LOW LEVEL INVERSIONS REMAIN IN PLACE. LATEST NAM BRINGS IN SOME LOW LEVEL MOISTURE AND POTENTIAL STRATUS OVER THE PLAINS WHILE THE GFS AND EUROPEAN ARE DRY. APPEARS MOST OF THE MOISTURE WITH THIS SYSTEM WILL BE TOO FAR NORTH AND EAST OF COLORADO FOR ANY BENEFIT. WARMER AGAIN ON WEDNESDAY AS HEIGHTS BUILD AS TEMPERATURES RETURN CLOSE TO CLIMATE NORMALS FOR THIS TIME OF YEAR. THE NEXT WEATHER MAKER WILL BE CLOSED LOW WHICH WILL BE OFF THE SOUTHERN CALIFORNIA COAST BY THURSDAY WHICH WILL RESULT IN SOME DOWNSTREAM RIDGING ACROSS COLORADO. THE FLOW ALOFT WILL SHIFT WEST TO SOUTHWEST THURSDAY AND FRIDAY AS MOISTURE VALUES SLOWLY ELEVATE. THE LOW IS PROGGED TO EJECT INTO COLORADO SOMETIME IN THE FRIDAY THROUGH SATURDAY TIME FRAME DEPENDING ON WHICH MODEL. SOLUTIONS VARY FROM THE SLOWER GFS SOLUTION TO THE FASTEST EUROPEAN. SEEMS LIKE THERE IS EVEN MORE VARIATION IN THE SOLUTIONS TODAY COMPARED TO YESTERDAY SO FORECAST CONFIDENCE NOT VERY HIGH. TYPICALLY THESE SYSTEMS END UP BEING SLOWER THAN FORECAST. NO MAJOR CHANGES PLANNED IN UPCOMING FORECAST PACKAGE FOR THE LONG TERM AND WILL KEEP LOW POPS FOR THE ENTIRE AREA ON FRIDAY AND SATURDAY. AVIATION...SO FAR THE HRRR AND THE RAP ARE NOT REAL EXCITED ABOUT LIFR CONDITIONS IN THE 10Z-15Z TIME PERIOD AS BOTH KEEP LIFR CONDITIONS TO THE NE OF THE AIRPORT. RAP STILL SHOWS A WEAK DENVER CYCLONE NR THE AIRPORT BY 12Z SO AM TEMPTED TO LEAVE IN A BRIEF 3 HR WINDOW FM 12Z-15Z FOR SOME LOWER CEILINGS AND FOG FOR NOW AS SKIES HAVE STARTED TO CLEAR. FOR THIS AFTN AND TONIGHT EXPECT VFR CONDITIONS. WINDS WILL BE LIGHT AND VARIABLE THIS MORNING AND THEN BECOME LIGHT NLY BY AFTN. FOR TONIGHT WINDS SHOULD BECOME DRAINAGE. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARJENBRUCH LONG TERM....ENTREKIN AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
921 AM EDT SUN OCT 7 2012 .UPDATE... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE ATLANTIC WATERS MAKING THEIR WAY ONSHORE THE SOUTHEAST FLORIDA COAST THIS MORNING. WATERSPOUTS ARE POSSIBLE WITH SOME OF THESE SHOWERS...SIMILAR TO YESTERDAY...AND WILL CONTINUE TO MENTION THIS IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. MORNING SOUNDING FROM MIAMI SHOWS LITTLE CHANGE FROM YESTERDAY WITH LOTS OF MOISTURE. THE SOUNDING FROM KEY WEST, HOWEVER, SHOWS A SUBTLE DRIER LAYER FROM 850 MB TO 700 MB. SHORT RANGE MODELS INCLUDING THE HRRR AREN`T SHOWING AS MUCH CONVECTION OVER THE SOUTHERN PENINSULA THIS AFTERNOON COMPARED TO PAST COUPLE OF DAYS. GLOBAL MODELS (GFS AND ECMWF) SHOW A WEAK MID-LEVEL SHORTWAVE PASSING THROUGH SOUTH FLORIDA THIS MORNING (POTENTIALLY CONTRIBUTING TO INCREASED ATLANTIC AND COASTAL CONVECTION THIS MORNING) AND OVER THE ATLANTIC THIS AFTERNOON. THE DRIER AIR OBSERVED AT KEY WEST MAY BE AN INDICATION OF SUBSIDENCE BEHIND THE SHORTWAVE AND MODELS COULD BE PICKING UP ON THIS. HAVING SAID ALL THIS, STILL EXPECT AT LEAST SCATTERED SHOWERS/TSTMS OVER INTERIOR AREAS THIS AFTERNOON WITH SLOW MOVEMENT OF CELLS LEADING TO LOCALLY HIGH RAINFALL AMOUNTS. HOWEVER, WOULD NOT BE SURPRISED TO SEE LESS ACTIVITY THIS AFTERNOON AS PER MODEL TRENDS INDICATED ABOVE. MOLLEDA && .PREV DISCUSSION... /ISSUED 727 AM EDT SUN OCT 7 2012/ AVIATION... CIRRUS CLOUDS COVER MUCH OF THE REGION THIS MORNING...FROM CONVECTION LAST NIGHT. LIGHT WINDS THIS MORNING WILL BECOME EASTERLY WITH DIURNAL HEATING LATER TODAY. A WEST COAST SEA BREEZE IS ALSO EXPECTED TO BECOME ESTABLISHED BY EARLY AFTERNOON. THIS WILL SET THE STAGE AGAIN FOR SCT TSRAS ACROSS MUCH OF THE SOUTH FLORIDA AREA...ESPECIALLY ACROSS INTERIOR AREAS. ACTIVITY SHOULD DIMINISH SHORTLY AFTER NIGHTFALL. PREV DISCUSSION... /ISSUED 255 AM EDT SUN OCT 7 2012/ SHORT TERM (TODAY-TUESDAY)... THE LATEST SURFACE ANALYSIS EARLIER THIS MORNING SHOWED A COLD FRONT EXTENDING SOUTHWEST FROM THE CAROLINAS TO THE CENTRAL GULF COAST STATES AND WEAK HIGH PRESSURE CENTERED NORTHEAST OF THE LOCAL AREA OFF THE NERN FLORIDA COAST ACROSS THE WESTERN ATLANTIC. MOIST EASTERLY LOW-LEVEL FLOW SOUTH OF THIS HIGH WILL PERSIST OVER THE AREA INTO MONDAY AS THE COLD FRONT GRADUALLY CONTINUES SOUTHEASTWARD INTO THE STATE AND HIGH PRESSURE BUILDS ACROSS THE REGION IN ITS WAKE. RECENTLY ANIMATED WATER VAPOR LOOP SHOWED BROAD CYCLONIC FLOW ACROSS THE MID-SECTION AND EASTERN HALF OF THE COUNTRY CHARACTERIZED WITH A FAIRLY STRONG SHORTWAVE TROUGH DIGGING SOUTHEAST AND EAST ACROSS THE PLAINS. MID TO UPPER SW FLOW ALONG WITH PLENTY OF MID/UPPER MOISTURE AHEAD OF THIS UPPER TROUGH CONTINUES TO STREAM OVERHEAD. MODEL SOUNDING PROFILES REMAIN FAIRLY WET ACROSS THE LOCAL AREA THROUGH THE BULK OF THIS SHORT-TERM PERIOD WITH PW`S REMAINING AROUND THE 2" INCH MARK. ONE MAIN DIFFERENCE OR TREND NOTED FROM RUN TO RUN WITHIN THE MODELS HAS BEEN THE DECREASE IN SOUTHWARD PROGRESSION OF THE FRONTAL BOUNDARY INTO OUR LOCAL AREA OVER THE NEXT COUPLE OF DAYS. THE LATEST MODEL CYCLE INDICATES THE BOUNDARY STALLING OVER CENTRAL FLORIDA SOMETIME BETWEEN MONDAY EVENING AND TUESDAY...WHEREAS BEFORE...ALL INDICATIONS INDICATED THE BOUNDARY PROGRESSING INTO THE AREA WITH DRIER AIR FILTERING IN BEHIND IT. THIS WILL RESULT IN THE RAIN CHANCES REMAINING IN THE FORECAST THROUGH THIS PERIOD WITH THE BEST POTENTIAL FOR THE DRIER AIR LATER THROUGH THE MID/LATTER HALF OF THE WEEK. THE LATEST WRF MODEL REFLECTIVITIES SUPPORT THIS AND GENERALLY INDICATE THE BULK OF THE ACTIVITY SETTING UP OVER THE INTERIOR AND GULF COAST REGIONS THROUGH THE AFTERNOON AND EVENING PERIODS. HOWEVER...SIMILAR TO YESTERDAY...SCATTERED SHOWERS AND STORMS DEVELOPING AND SPREADING WEST ACROSS THE EASTERN HALF OF THE AREA WILL REMAIN POSSIBLE THROUGH THE FIRST HALF OF THE DAY TODAY. THE LATEST MODEL GUIDANCE INDICATES AN ADDITIONAL HALF OF AN INCH TO AN INCH ACROSS THE WESTERN HALF OF THE AREA OVER THE UPCOMING FEW DAYS...WHICH LINES UP WELL WITH THE LATEST HPC GUIDANCE. LOCALLY HIGHER AMOUNTS WILL REMAIN POSSIBLE WHERE THE ACTIVITY BECOMES CONCENTRATED THROUGH THIS TIME. AS A RESULT...THE MAIN CONCERNS WILL BE THE POTENTIAL FOR LOCALIZED FLOODING AND WET MICROBURSTS/GUSTY WINDS IN AND AROUND THE HEAVIER ACTIVITY OR STRONG STORMS THAT DEVELOP. LONG TERM...(TUESDAY NIGHT-SATURDAY) THE LATEST GFS/GFS ENSEMBLE AND ECMWF REMAIN IN DECENT AGREEMENT ON THE LARGE SCALE THROUGH THE MID-WEEK PERIOD AND GENERALLY KEEP THE BROAD CYCLONE FLOW IN PLACE ACROSS THE EASTERN STATES. HOWEVER...ALL CONTINUE TO SUGGEST MUCH DRIER DEEP LAYER AIR SPREADING SOUTH AS THE PREVIOUSLY DISCUSSED FRONTAL BOUNDARY STALLS AND DIMINISHES AND THE MEAN UPPER TROUGH AXIS SHIFTS EWD. THIS DRY AIR WILL TRANSLATE TO A SLIGHT DECREASE IN DEWPOINTS...POSSIBLY INTO THE UPPER 60S INLAND AND NORTH AROUND THE LAKE REGION. WILL REFLECT THIS WITH DECREASING RAINFALL CHANCES THROUGH THIS TIME ACROSS THE AREA. NO NOTABLE CHANGES REGARDING THE DAILY HIGH AND LOW TEMPERATURES THROUGH THIS EXTENDED PERIOD. MARINE... LIGHT EASTERLY FLOW WILL PERSIST INTO THE UPCOMING WEEK AS A WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND NORTHWEST. SCATTERED SHOWERS AND STORMS WILL REMAIN IN THE FORECAST THROUGH THIS TIME. DRIER AIR WITH LIGHT TO MODERATE NORTHEAST WINDS WILL BECOME A POSSIBILITY THROUGH THE MIDDLE PART OF THE UPCOMING WEEK. SEAS WILL RESPOND AND INCREASE INTO THE 3 TO 5 FOOT RANGE ACROSS THE ATLANTIC WATERS. FIRE WEATHER... DESPITE THE DRIER AIR PROGGED TO FILTER INTO THE AREA FROM NORTH TO SOUTH NEXT WEEK...RELATIVE HUMIDITIES ARE FORECAST TO REMAIN WELL ABOVE CRITICAL LEVELS WITH NO RED FLAG CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 77 88 78 / 40 30 40 30 FORT LAUDERDALE 85 79 88 77 / 40 30 40 30 MIAMI 88 78 89 77 / 40 30 40 30 NAPLES 88 75 90 75 / 40 30 40 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
601 AM MDT SUN OCT 7 2012 .UPDATE... ISSUED AT 558 AM MDT SUN OCT 7 2012 UPDATED THE FORECAST TO CANCELL THE SOUTHWEST PORTION OF THE FREEZE WARNING. && .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 243 AM MDT SUN OCT 7 2012 FORECAST CONCERNS WILL BE HOW MUCH THE TEMPERATURES MODERATE THROUGH MONDAY BEFORE THE NEXT COLD FRONT MOVES IN TO COOL OFF TUESDAY. SATELLITE CONTINUING TO SHOW AN AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA. FLOW DOMINATED BY A BLOCK ALONG THE WEST COAST AND A TROUGH OVER THE CENTRAL AND EASTERN PORTION OF THE COUNTRY. COLD AND MOIST AIR MASS REMAINS OVER THE CENTRAL PORTION OF THE COUNTRY. MODELS INITIALIZED FINE AT THE JET AND MID LEVELS. NAM WAS CATCHING THE SURFACE RIDGING AND WIND FIELD IN OUR AREA THE BEST. NAM AND RUC APPEAR TO BE CATCHING THE STRATUS FIELD THE BEST. THE GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE REST ON THE LOW LEVEL THERMAL FIELD. TODAY/TONIGHT...STRATUS KEEPS EDGING EVER SO SLOWLY SOUTHWEST. NOT SURE HOW MUCH FURTHER IT WILL GO. LOCATIONS ON THE EDGE OF THIS CLOUD FIELD ARE NOT THAT FAR AWAY FROM REACHING THE NEEDED TEMPERATURES FOR THE FREEZE WARNING TO VERIFY. AT THIS TIME I WILL LET THE FREEZE WARNING CONTINUE BUT FEELING IS THAT THE FAR SOUTHWEST AND WESTERN PORTIONS WILL NOT MAKE IT. SOME FOG HAS DEVELOPED. THE 00Z NAM DRASTICALLY OVERDID THE FOG. THE 06Z NAM IS NOW MORE REALISTIC AND DEVELOPING FOG IN AREAS THAT HAVE CLEARED. THE HRRR AND RUC DO NOT AGREE WITH EACH OTHER BUT TEND TO FAVOR THE WEST AND MORE IN LOCATIONS THAT HAVE THE STRATUS. AT THIS TIME WILL ADD FOG PER THE LATEST NAM WHICH DOES MAKE SENSE. WEAK LEFT FRONT QUADRANT OF THE UPPER JET AND A RATHER STRONG SHORTWAVE MOVES THROUGH DURING THE LATE MORNING AND AFTERNOON. WILL HAVE TO KEEP WATCHING BUT THESE FEATURES LOOK TO SPREAD SOME HIGHER LEVEL CLOUD COVER ACROSS THE AREA. TEMPERATURES TODAY WILL BE AFFECTED BY HOW FAST THE STRATUS LEAVES WHICH LOOKS TO BE BY LATE MORNING. HAVE AN AREA IN THE NORTHERN PORTION OF THE AREA THAT HAD SIX PLUS INCHES OF SNOW YESTERDAY. AREAS DOWNSTREAM OF SNOW FIELD COULD BE AFFECT. WITH WARM GROUND WOULD IMAGINE THAT SNOW WOULD MELT A LITTLE FASTER THAN NORMAL. WILL DEFINITELY HAVE AN AFFECT TODAY ON THE TEMPERATURES AND MADE THAT AREA COOLER THAN SURROUNDING LOCATIONS. IF STRATUS HOLDS ON LONGER ALL THE TEMPERATURES MAY END UP BEING TOO WARM. MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF UPPER JET MOVES ACROSS AT THE BEGINNING OF THE DAY. IT LOOKS LIKE IT WILL SPREAD SOME CLOUDS ACROSS THE AREA. MODELS SHOW GOOD DOWNSLOPE WINDS THROUGH MOST OF THE DAY UNTIL THEY BECOME LIGHTER AND MORE IN THE MIDDLE OF THE AFTERNOON. SO WILL TREND TOWARD THE WARMER GUIDANCE. THERE IS SOME MODEL DIFFERENCES IN HOW TO HANDLE THE SYSTEM DIGGING OUT OF CENTRAL CANADA. THE NAM IS FASTER AND DEEPER. GFS IS NOT AS DEEP. OTHER MODELS ARE FAIRLY DEEP...SLOWER AND ARE A LITTLE FURTHER SOUTHWEST. AS A CONSEQUENCE THE NAM IS THE FASTEST TO PUSH THE FRONT THROUGH AND THROUGH MOST OF THE AREA BY 12Z. IT IS ALWAYS POSSIBLE IN THIS SCENARIO THAT FRONTS WILL COME IN FASTER BUT AM LEARY OF THE NAM A LITTLE. SO WENT IN THE MIDDLE OF THE SOLUTIONS. TUESDAY/TUESDAY NIGHT...ABOVE MENTIONED JET MOVES ACROSS DURING THE MORNING BUT MODELS INDICATE VERY LITTLE CLOUD COVER WILL BE GENERATED BY THIS FEATURE. ALL THE MODELS HAVE THE FRONT THROUGH THE FORECAST AREA BY 18Z. THERE IS A LITTLE BIT OF SPREAD IN HOW MUCH COOLING TAKES PLACE. THE NAM IS THE WARMEST BUT NOT BY MUCH AND THE ECMWF THE COOLEST. THE OTHER MODELS CLUSTER IN THE MIDDLE. AT THIS TIME WILL GO WITH A COMPROMISE OF TEMPERATURES WHICH DOES LOWER THE MAXES A LITTLE. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 243 AM MDT SUN OCT 7 2012 THE UPPER PATTERN DURING THIS PERIOD WILL TRANSITION FROM FAST NORTHWEST FLOW ALOFT ON WED TO UPPER RIDGING THU-EARLY FRI TO STRONG SOUTHWEST FLOW LATER FRI-SAT AS THE UPPER LOW APPROACHING CALIFORNIA EJECTS NORTHEAST ACROSS THE CENTRAL HIGH PLAINS. NUMERICAL GUIDANCE HAS VASTLY DIFFERING SOLUTIONS ON WHERE AND HOW FAST THE UPPER LOW LIFTS OUT OF THE SOUTHWEST U.S. WHICH IS ULTIMATELY TIED TO THE LOCATION AND INTENSITY OF THE NEXT UPSTREAM TROUGH. THE EC IS NOW CONSIDERABLY FASTER AND MUCH FURTHER NORTH COMPARED TO GFS. SATURDAY MORNING THE EC HAS THE UPPER LOW OVER CENTRAL NEBRASKA WHILE GFS HOLDS IT BACK OVER THE FOUR CORNERS. THE GEM WAS PRETTY MUCH IN STEP WITH THE GFS THRU 144 HRS /FRI/. NEEDLESS TO SAY...CONFIDENCE IS LOW IN THE TIMING AND AMOUNT OF ASSOCIATED PRECIP IN THE FRI-SAT TIME FRAME. EXPERIENCE WOULD FAVOR A SLOWER /GFS/ MOVEMENT BUT A BLEND IS PROBABLY APPROPRIATE AT THIS POINT. WHICHEVER MODEL VERIFIES... IF EITHER ONE DOES... WILL ALSO MAKE A BIG DIFFERENCE IN THE POTENTIAL TO GET DRY SLOTTED. WHATEVER THE OUTCOME...LOOKS LIKE A RETURN TO MORE TYPICAL OCTOBER TEMPERATURES GIVEN THE UPPER PATTERN CHANGE DURING PERIOD. AT THE SURFACE...ONE LAST CANADIAN HIGH PRESSURE AREA WILL DROP SOUTHEAST INTO THE AREA THURSDAY BEFORE UPPER RIDGING AND SOUTHWEST FLOW ALOFT TAKE OVER. THE EC IS A LITTLE SLOWER WITH THE COLD FRONTAL PASSAGE COMPARED TO GFS/GEM WHICH COULD MAKE THURSDAY MAX TEMPS A LITTLE TRICKY. CURRENT FORECAST HAS MAX TEMPERATURES IN THE UPPER 60S/LOWER 70S BEFORE FRONTAL PASSAGE. THE NEXT SHOT AT PRECIP LOOKS TO BE TOWARD THE END OF THIS FORECAST PERIOD WITH TIMING DEPENDING ON SPEED AT WHICH UPPER LOW EJECTS NORTHEAST. THE EC BRINGS IN POTENTIAL FOR SHOWERS AND THUNDERSTORMS EARLY FRIDAY MORNING WHILE GFS TIMING IS FRIDAY NIGHT INTO SATURDAY. CURRENT FORECAST IS A BLEND OF NUMERICAL GUIDANCE AND BRINGS IN CHANCE POPS STARTING FRIDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 558 AM MDT SUN OCT 7 2012 KGLD WILL HAVE MVFR CONDITIONS UNTIL 18Z THEN VFR FOR THE REMAINDER OF THE PERIOD. KMCK WILL HAVE LIFR CONDITIONS BEFORE GRADUALLY IMPROVING BY 18Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR KSZ001>004- 014>016-028-029. CO...FREEZE WARNING UNTIL 9 AM MDT THIS MORNING FOR COZ090. NE...FREEZE WARNING UNTIL 9 AM MDT /10 AM CDT/ THIS MORNING FOR NEZ079>081. && $$ UPDATE...BULLER SHORT TERM...BULLER LONG TERM...DLF AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
953 AM EDT SUN OCT 7 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD ACROSS THE REGION EARLY TODAY. LOW PRESSURE WILL TRACK EAST OF THE GULF OF MAINE TONIGHT INTO MONDAY MORNING. HIGH PRESSURE WILL RIDGE ACROSS THE REGION ON MONDAY. && .NEAR TERM /THROUGH TONIGHT/... 950 AM UPDATE...ONLY MINOR ADJUSTMENTS NEEDED FOR THIS UPDATE. INCREASED POPS JUST A BIT LATE THIS AFTERNOON AS PER HRRR MODEL, WHICH IS SHOWING ISOLATED SHOWERS COMING INTO FAR SOUTHERN PORTIONS OF THE AREA TOWARD 4-5 PM. ALSO TWEAKED SKY COVER TO MATCH CURRENT SATELLITE. NO OTHER CHANGES NEEDED. PREVIOUS DISCUSSION... MAIN CHALLENGE WILL BE OF COURSE THE TEMPERATURES AND QPF. WEAK HIGH PRES RIDGING WILL QUICKLY GIVE WAY TO THE NEXT SYSTEM APCHG FROM MID ATLC REGION LATER THIS AFTERNOON INTO TONIGHT. CLOUDS WILL BE BACK ON THE INCREASE AFTER SOME PARTIAL CLEARING IN ADVANCE OF THE WEAK LOW APCHG FROM THE S TODAY. TEMPERATURES WILL BE COOLER THAN THEY HAVE BEEN THE LAST FEW DAYS W/READINGS BACK TO AOB NORMAL LEVELS FOR EARLY OCTOBER. DECIDED ON A BLEND OF THE NAM12 AND GMOS FOR TODAY/S MAXES WHICH SHOWS LOW TO MID 50S NORTH AND MID TO TO UPPER 50S CENTRAL AND DOWNEAST. THE CHALLENGE FOR TONIGHT IS HOW FAR NORTH WILL PRECIP GET AND HOW COLD WILL TEMPERATURES BE. ALL THE SHORT RANGE GUIDANCE INCLUDING THE CANADIAN GEM/NAM AND GFS SHOW PRECIP SHIELD EDGING ITS WAY INTO COASTAL AND SWRN AREAS BY EARLY EVENING. THE PRECIP IS EXPECTED TO SPREAD NNE OVERNIGHT AS LOW PRES MOVES NE ACROSS THE GULF OF MAINE. ATTM, THE BEST LIFT APPEARS TO BE SITUATED ACROSS THE DOWNEAST AND EASTERN SECTIONS AND THIS IS WHERE THE HIGHER QPF VALUES WERE PLACED(.25-.30"). THE 00Z NAM AND GFS BOTH POINT TO A VIGOROUS VORTICITY MAX W/DECENT ADVECTION TO MOVE ACROSS THE STATE OVERNIGHT INTO EARLY MONDAY MORNING. THIS WILL AID IN PROVIDING ADDITION LIFT FOR PRECIP. THE 00Z ECWMF SHOWS THIS FEATURE AS WELL AS DOES THE LATEST WV SATL IMAGERY W/THE VORT MAX OVER MISSOURI. THEREFORE, SQUEEZED POPS DOWN SOME W/40-50% ACROSS THE FAR N AND NW AND LIKELY TO CATEGORICAL(60-90%) FOR THE CENTRAL AND DOWNEAST REGION INCLUDING THE COAST. PRECIP WILL BE IN THE FORM OF RAIN FOR ALL AREAS AS TEMPERATURES WILL REMAIN ABOVE 32-33F. THE EXCEPTION TO THIS WILL BE THE FAR W AND NW AREAS AS SOME SNOW COULD MIX IN W/THE RAIN BY 09Z MONDAY AS TEMPERATURES ARE EXPECTED TO FALL BACK INTO THE LOWER 30S(33-34F). THE 00Z ECMWF HAS 925MB TEMPERATURES FALLING TO NEAR 0C IN THESE AREAS BY EARLY MONDAY MORNING. 07Z SFC ANALYSIS SHOWED TEMPERATURES IN THE LOW 30S ACROSS WESTERN QUEBEC AND OTTAWA. IF THE CHANGEOVER OCCURS, IT WILL BE BRIEF AS THE PRECIP WILL SHUT OFF QUICKLY AS THE LOW EXITS ACROSS NOVA SCOTIA AND HIGH PRES BEGINS TO RIDGE FROM THE S. && .SHORT TERM /MONDAY THROUGH TUESDAY/... THE START OF THE SHORT TERM FINDS THE MODELS IN GOOD AGREEMENT. A LOW OVER ERN NOVA SCOTIA AND ASSOCIATED FRONTAL SYSTEM EXITING THE AREA TO THE EAST...A HIGH PRESSURE RIDGE DOMINATING THE WEATHER ACROSS MUCH OF THE MIDDLE AND ERN PORTIONS OF THE UNITED STATES. A MAJOR SHORT WAVE TROUGH EXTENDING SOUTH ACROSS LAKE MICHIGAN INTO NRN LA. A NEW LOW MVG SE OUT OF WRN CANADA INTO THE NRN PLAINS. MON EVNG THE THE LOW OVR NOVA SCOTIA MOVES EAST INTO THE MARITIMES. THE HIGH PRESSURE RIDGE EXTENDS ACROSS MAINE. THE NEW LOW MOVES SE INTO LAKE SUPERIOR...AN ASSOCIATED UPPER LOW STACKED TO THE NW OF THE SFC LOW. THE SHORT WAVE TROUGH MOVES EAST TO THE APPALACHIANS. TUES MRNG THE LOW OVR LAKE SUPERIOR MOVES NE TO THE NRN TIP OF SUPERIOR...THE UPPER LOW CONTINUES TO SUPPORT THE SFC LOW. BY THE END OF THE PERIOD. THE HIGH PRESSURE RIDGE REMAINS OVER MAINE. THE LOW OVR NRN LAKE SUPERIOR MOVES NE INTO SRN JAMES BAY...DEEPENS AT THIS POINT THE UPPER LOW HAS BECOME VERTICALLY STACKED WITH THE SFC SYSTEM. LOADED MATCH GUIDANCE FOR MAX/MIN. BLENDED THE GFS/NAM HRLY TEMP/DP. BLENDED THE GFS/NAM/OFFICIAL FOR WNDS/SKY/POP. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AT THE START OF THE LONG TERM THE MODELS CONTINUE TO BE IN GOOD AGREEMENT. A HIGH PRESSURE RIDGE EXTENDING FROM ERN QUEBEC TO THE GULF OF MEXICO WILL DOMINATE THE WEATHER FOR THE LOCAL AREA EARLY IN THE PERIOD. A DEEPENING LOW OVER SRN JAMES BAY...WITH AN ASSOCIATED FRONT WRAPPED AROUND THE LOW THEN EXTENDING SOUTH THROUGH WRN LAKE HURON...LAKE MICHIGAN...TO NWRN IL. BY WED EVNG THE FRONT MOVES EAST INTO WRN MAINE...THE ASSOCIATED LOW CONTINUES TO MOVE NE INTO NRN QUEBEC. THE ASSOCIATED SHORT WAVE EXTENDS THROUGH THE ERN GREAT LAKES TO SRN GA. A NEW LOW MOVES INTO THE NRN PLAINS FROM NW CANADA. THURS MRNG THE FRONT MOVES THROUGH MAINE...HIGHER PRESSURE STARTS TO BUILD INTO SW ME. THE NEW LOW MOVES EAST TO LAKE SUPERIOR. THE UPPER LVLS WILL BECOME MORE ZONAL. SYSTEMS WILL TRANSIT QUICKLY ACROSS THE NRN US...BY THURS EVNG THE NEW LOW TRACK ACROSS THE GREAT LAKE TO SRN QUEBEC. BY EARLY FRI MRNG THE LOW WILL MOVE INTO NW ME. BY FRI MRNG (THE GFS) THE LOW WILL BE INTO NRN NEW BRUNSWICK AND HIGHER PRESSURE WILL BEGIN TO BUILD INTO ME. (THE ECMWF) THE LOW WILL MOVE TO CNTRL QUEBEC...TRAILING A FRONT ACROSS NW ME. FRI EVNG THE GFS MOVES THE SYSTEM WELL EAST OF MAINE...BEGINS TO BUILD HIGHER PRESSURE. THE ECMWF MOVES THE LOW AND ASSOCIATED FRONT EAST OF MAINE. HIGHER PRESSURE WILL DOMINATE THROUGH SAT. BY SAT EVNG THERE WILL BE A NEW LOW OVR WRN KS THIS LOW WILL DEEPEN RAPIDLY...AND MOVE NE TO NRN IA...ITS ASSOCIATED WARM FRONT WILL EXTEND EAST INTO SRN NH. BY THE END OF THE PERIOD THE LOW WILL BE OVER SRN QUEBEC. THE ASSOCIATED WARM FRONT EXTENDING THROUGH MAINE. LOADED GMOS... ADJUSTED SKY/POPS WITH GFS FOR WED-SAT. GMOS GUIDANCE TO HIGH GFS. LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. ADDED 20 PERCENT FOR WNDS OVR THE WATERS...15 PERCENT OVR LAND. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... NEAR TERM: VFR LOOKS TO BE THE GOING RATE INTO EARLY EVENING AND THEN MVFR CONDITIONS POSSIBLE ACROSS KBGR AND KBHB. VFR IS EXPECTED TO HOLD ACROSS THE NORTHERN TERMINALS. SHORT TERM: MVFR CONDITIONS AT ALL SITES RAPIDLY IMPROVING AS FRONTAL SYSTEM MOVES EAST OF THE AREA. VFR CONDITIONS AT ALL SITES BY MID MORNING MONDAY. VFR CONDITIONS WILL CONTINUE INTO TUESDAY...ISOLATED SHOWER/THUNDERSTORMS FOR BGR...BHB TUESDAY AFTERNOON...MVFR TO IFR CONDITIONS DURING PCPN. CONDITIONS WILL FALL TO MVFR ON WEDNESDAY SOUTH TO NORTH...BHB...BGR IN THE MORNING THE OTHER SITES DURING THE AFTERNOON AS A LOW PRESSURE CENTER TRANSITS THROUGH THE GULF OF MAINE. IFR CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD. && .MARINE... NEAR TERM: DROPPED THE SCA AS WINDS/SEAS ARE BELOW CRITERIA. NO HEADLINES FOR THIS TERM. USED A BLEND OF THE NAM12 AND GFS FOR THE WINDS WHICH SUPPORTS 10-15 KTS SUSTAINED BY TONIGHT. STAYED CLOSE TO THE DAYCREW`S WAVE HEIGHTS OF 2-3 FT. SHORT TERM: WINDS AND SEAS WILL REMAIN BELOW SCA THROUGH MID DAY WEDNESDAY. SEAS WILL BEGIN TO BUILD AT WEDNESDAY EVENING AS A FRONTAL SYSTEM MOVES INTO THE GULF OF MAINE WATERS. AN SCA MAYBE REQUIRED WED THROUGH THURS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HASTINGS/HEWITT SHORT TERM...NORTON LONG TERM...NORTON AVIATION...HASTINGS/HEWITT MARINE...HASTINGS/HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS CARIBOU ME
645 AM EDT SUN OCT 7 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD ACROSS THE REGION EARLY TODAY. LOW PRESSURE WILL TRACK EAST OF THE GULF OF MAINE TONIGHT INTO MONDAY MORNING. HIGH PRESSURE WILL RIDGE ACROSS THE REGION ON MONDAY. && .NEAR TERM /THROUGH TONIGHT/... UPDATE: ADJUSTED THE SKY CONDITIONS USING THE LATEST IR SATL IMAGERY AND THE HRRR WHICH APPEARS TO BE DOING WELL. CLEARING WILL GIVE WAY TO CLOUDS LATER THIS MORNING INTO THE AFTERNOON. ADJUSTED THE HRLY TEMPS AS WELL UPWARD AS PREVIOUS THINKING WAS TOO COLD. PULL THE FOG FOR THE REMAINDER OF THE MORNING. PREVIOUS DISCUSSION... MAIN CHALLENGE WILL BE OFF COURSE THE TEMPERATURES AND QPF. WEAK HIGH PRES RIDGING WILL QUICKLY GIVE WAY TO THE NEXT SYSTEM APCHG FROM MID ATLC REGION LATER THIS AFTERNOON INTO TONIGHT. CLOUDS WILL BE BACK ON THE INCREASE AFTER SOME PARTIAL CLEARING IN ADVANCE OF THE WEAK LOW APCHG FROM THE S TODAY. TEMPERATURES WILL BE COOLER THAN THEY HAVE BEEN THE LAST FEW DAYS W/READINGS BACK TO AOB NORMAL LEVELS FOR EARLY OCTOBER. DECIDED ON A BLEND OF THE NAM12 AND GMOS FOR TODAY/S MAXES WHICH SHOWS LOW TO MID 50S NORTH AND MID TO TO UPPER 50S CENTRAL AND DOWNEAST. THE CHALLENGE FOR TONIGHT IS HOW FAR NORTH WILL PRECIP GET AND HOW COLD WILL TEMPERATURES BE. ALL THE SHORT RANGE GUIDANCE INCLUDING THE CANADIAN GEM/NAM AND GFS SHOW PRECIP SHIELD EDGING ITS WAY INTO COASTAL AND SWRN AREAS BY EARLY EVENING. THE PRECIP IS EXPECTED TO SPREAD NNE OVERNIGHT AS LOW PRES MOVES NE ACROSS THE GULF OF MAINE. ATTM, THE BEST LIFT APPEARS TO BE SITUATED ACROSS THE DOWNEAST AND EASTERN SECTIONS AND THIS IS WHERE THE HIGHER QPF VALUES WERE PLACED(.25-.30"). THE 00Z NAM AND GFS BOTH POINT TO A VIGOROUS VORTICITY MAX W/DECENT ADVECTION TO MOVE ACROSS THE STATE OVERNIGHT INTO EARLY MONDAY MORNING. THIS WILL AID IN PROVIDING ADDITION LIFT FOR PRECIP. THE 00Z ECWMF SHOWS THIS FEATURE AS WELL AS DOES THE LATEST WV SATL IMAGERY W/THE VORT MAX OVER MISSOURI. THEREFORE, SQUEEZED POPS DOWN SOME W/40-50% ACROSS THE FAR N AND NW AND LIKELY TO CATEGORICAL(60-90%) FOR THE CENTRAL AND DOWNEAST REGION INCLUDING THE COAST. PRECIP WILL BE IN THE FORM OF RAIN FOR ALL AREAS AS TEMPERATURES WILL REMAIN ABOVE 32-33F. THE EXCEPTION TO THIS WILL BE THE FAR W AND NW AREAS AS SOME SNOW COULD MIX IN W/THE RAIN BY 09Z MONDAY AS TEMPERATURES ARE EXPECTED TO FALL BACK INTO THE LOWER 30S(33-34F). THE 00Z ECMWF HAS 925MB TEMPERATURES FALLING TO NEAR 0C IN THESE AREAS BY EARLY MONDAY MORNING. 07Z SFC ANALYSIS SHOWED TEMPERATURES IN THE LOW 30S ACROSS WESTERN QUEBEC AND OTTAWA. IF THE CHANGEOVER OCCURS, IT WILL BE BRIEF AS THE PRECIP WILL SHUT OFF QUICKLY AS THE LOW EXITS ACROSS NOVA SCOTIA AND HIGH PRES BEGINS TO RIDGE FROM THE S. && .SHORT TERM /MONDAY THROUGH TUESDAY/... THE START OF THE SHORT TERM FINDS THE MODELS IN GOOD AGREEMENT. A LOW OVER ERN NOVA SCOTIA AND ASSOCIATED FRONTAL SYSTEM EXITING THE AREA TO THE EAST...A HIGH PRESSURE RIDGE DOMINATING THE WEATHER ACROSS MUCH OF THE MIDDLE AND ERN PORTIONS OF THE UNITED STATES. A MAJOR SHORT WAVE TROUGH EXTENDING SOUTH ACROSS LAKE MICHIGAN INTO NRN LA. A NEW LOW MVG SE OUT OF WRN CANADA INTO THE NRN PLAINS. MON EVNG THE THE LOW OVR NOVA SCOTIA MOVES EAST INTO THE MARITIMES. THE HIGH PRESSURE RIDGE EXTENDS ACROSS MAINE. THE NEW LOW MOVES SE INTO LAKE SUPERIOR...AN ASSOCIATED UPPER LOW STACKED TO THE NW OF THE SFC LOW. THE SHORT WAVE TROUGH MOVES EAST TO THE APPALACHIANS. TUES MRNG THE LOW OVR LAKE SUPERIOR MOVES NE TO THE NRN TIP OF SUPERIOR...THE UPPER LOW CONTINUES TO SUPPORT THE SFC LOW. BY THE END OF THE PERIOD. THE HIGH PRESSURE RIDGE REMAINS OVER MAINE. THE LOW OVR NRN LAKE SUPERIOR MOVES NE INTO SRN JAMES BAY...DEEPENS AT THIS POINT THE UPPER LOW HAS BECOME VERTICALLY STACKED WITH THE SFC SYSTEM. LOADED MATCH GUIDANCE FOR MAX/MIN. BLENDED THE GFS/NAM HRLY TEMP/DP. BLENDED THE GFS/NAM/OFFICIAL FOR WNDS/SKY/POP. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AT THE START OF THE LONG TERM THE MODELS CONTINUE TO BE IN GOOD AGREEMENT. A HIGH PRESSURE RIDGE EXTENDING FROM ERN QUEBEC TO THE GULF OF MEXICO WILL DOMINATE THE WEATHER FOR THE LOCAL AREA EARLY IN THE PERIOD. A DEEPENING LOW OVER SRN JAMES BAY...WITH AN ASSOCIATED FRONT WRAPPED AROUND THE LOW THEN EXTENDING SOUTH THROUGH WRN LAKE HURON...LAKE MICHIGAN...TO NWRN IL. BY WED EVNG THE FRONT MOVES EAST INTO WRN MAINE...THE ASSOCIATED LOW CONTINUES TO MOVE NE INTO NRN QUEBEC. THE ASSOCIATED SHORT WAVE EXTENDS THROUGH THE ERN GREAT LAKES TO SRN GA. A NEW LOW MOVES INTO THE NRN PLAINS FROM NW CANADA. THURS MRNG THE FRONT MOVES THROUGH MAINE...HIGHER PRESSURE STARTS TO BUILD INTO SW ME. THE NEW LOW MOVES EAST TO LAKE SUPERIOR. THE UPPER LVLS WILL BECOME MORE ZONAL. SYSTEMS WILL TRANSIT QUICKLY ACROSS THE NRN US...BY THURS EVNG THE NEW LOW TRACK ACROSS THE GREAT LAKE TO SRN QUEBEC. BY EARLY FRI MRNG THE LOW WILL MOVE INTO NW ME. BY FRI MRNG (THE GFS) THE LOW WILL BE INTO NRN NEW BRUNSWICK AND HIGHER PRESSURE WILL BEGIN TO BUILD INTO ME. (THE ECMWF) THE LOW WILL MOVE TO CNTRL QUEBEC...TRAILING A FRONT ACROSS NW ME. FRI EVNG THE GFS MOVES THE SYSTEM WELL EAST OF MAINE...BEGINS TO BUILD HIGHER PRESSURE. THE ECMWF MOVES THE LOW AND ASSOCIATED FRONT EAST OF MAINE. HIGHER PRESSURE WILL DOMINATE THROUGH SAT. BY SAT EVNG THERE WILL BE A NEW LOW OVR WRN KS THIS LOW WILL DEEPEN RAPIDLY...AND MOVE NE TO NRN IA...ITS ASSOCIATED WARM FRONT WILL EXTEND EAST INTO SRN NH. BY THE END OF THE PERIOD THE LOW WILL BE OVER SRN QUEBEC. THE ASSOCIATED WARM FRONT EXTENDING THROUGH MAINE. LOADED GMOS... ADJUSTED SKY/POPS WITH GFS FOR WED-SAT. GMOS GUIDANCE TO HIGH GFS. LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. ADDED 20 PERCENT FOR WNDS OVR THE WATERS...15 PERCENT OVR LAND. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... NEAR TERM: VFR LOOKS TO BE THE GOING RATE INTO EARLY EVENING AND THEN MVFR CONDITIONS POSSIBLE ACROSS KBGR AND KBHB. VFR IS EXPECTED TO HOLD ACROSS THE NORTHERN TERMINALS. SHORT TERM: MVFR CONDITIONS AT ALL SITES RAPIDLY IMPROVING AS FRONTAL SYSTEM MOVES EAST OF THE AREA. VFR CONDITIONS AT ALL SITES BY MID MORNING MONDAY. VFR CONDITIONS WILL CONTINUE INTO TUESDAY...ISOLATED SHOWER/THUNDERSTORMS FOR BGR...BHB TUESDAY AFTERNOON...MVFR TO IFR CONDITIONS DURING PCPN. CONDITIONS WILL FALL TO MVFR ON WEDNESDAY SOUTH TO NORTH...BHB...BGR IN THE MORNING THE OTHER SITES DURING THE AFTERNOON AS A LOW PRESSURE CENTER TRANSITS THROUGH THE GULF OF MAINE. IFR CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD. && .MARINE... NEAR TERM: DROPPED THE SCA AS WINDS/SEAS ARE BELOW CRITERIA. NO HEADLINES FOR THIS TERM. USED A BLEND OF THE NAM12 AND GFS FOR THE WINDS WHICH SUPPORTS 10-15 KTS SUSTAINED BY TONIGHT. STAYED CLOSE TO THE DAYCREW`S WAVE HEIGHTS OF 2-3 FT. SHORT TERM: WINDS AND SEAS WILL REMAIN BELOW SCA THROUGH MID DAY WEDNESDAY. SEAS WILL BEGIN TO BUILD AT WEDNESDAY EVENING AS A FRONTAL SYSTEM MOVES INTO THE GULF OF MAINE WATERS. AN SCA MAYBE REQUIRED WED THROUGH THURS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT SHORT TERM...NORTON LONG TERM...NORTON AVIATION...HEWITT MARINE...HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1151 AM EDT SUN OCT 7 2012 .SYNOPSIS... A NORTHEASTBOUND COLD UPPER LEVEL TROUGH WILL PROVIDE SCATTERED SHOWERS THIS AFTERNOON. THEN HIGH PRESSURE WILL FOLLOW WITH CLEARING SKIES AND LIGHT WINDS TONIGHT...WHICH MEANS TEMPERATURES MAY DROP BELOW FREEZING EARLY MONDAY MORNING...WITH AREAS OF FROST AND PATCHY FOG. THE HIGH PRESSURE WILL PROVIDE DRY CONDITIONS THE REST OF MONDAY AND TUESDAY BEFORE A CANADIAN COLD FRONT BRINGS SHOWERS WEDNESDAY. && .NEAR TERM /THROUGH MONDAY/... CONCUR WITH RECENT RAP AND WRF-NMM MODEL OUTPUT THAT A COLD UPPER LEVEL TROUGH WILL MOVE NORTHEASTWARD THROUGH THE UPPER OHIO VALLEY THIS AFTERNOON WITH SCATTERED SHOWERS. AS RECENT SREF MODEL OUTPUT AND NAM MODEL PROFILES CONTINUE TO SHOW...HIGH PRESSURE WILL FOLLOW WITH CLEARING SKIES AND LIGHT WINDS BY LATE TONIGHT. THIS SCENARIO WILL BE IDEAL FOR STRONG NOCTURNAL RADIATIONAL COOLING. HENCE WITH THIS AFTERNOONS HIGH TEMPERATURES RESTRICTED BY THE COOL CLOUDY CONDITIONS...AS RECENT GFS LAMP SHOWS MOST PLACES WILL STRUGGLE TO REACH 50...CONTINUE TO EXPECT LOW TEMPERATURES EARLY MONDAY MORNING TO BE MAINLY IN THE 30 TO 35 RANGE...AS RECENT GFS AND NAM MOS INDICATE. RECENT NAM MODEL PROFILES SHOW A PARTICULARLY STRONG YET SHALLOW SURFACE TEMPERATURE INVERSION. SO WITH AFTERNOON SURFACE DEW POINTS IN THE THE MID 30S...IT STILL APPEARS PLAUSIBLE FOG CAN DEVELOP LATE TONIGHT...WITH THE RIVER VALLEYS MORE VULNERABLE THAN ELSEWHERE. SO HAVE CONTINUED THE FREEZE WARNING WITH MENTION OF EARLY MORNING AREAS OF FROST AND PATCHY RIVER VALLEY FOG. HIGH PRESSURE SUBSIDENCE WILL ENSURE MOSTLY SUNNY CONDITIONS THE REST OF DAYTIME MONDAY WITH AFTERNOON HIGH TEMPERATURES 5 TO 8 DEGREES COLDER THAN NORMAL AS SHOWN BY RECENT GFS AND NAM MOS. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... RECENT SREF MODEL OUTPUT SHOWS HIGH PRESSURE WILL CONTINUE TO PROVIDE DRY AND RELATIVELY CLOUD FREE CONDITIONS THROUGH DAYTIME TUESDAY. THEN A COLD FRONT...WITH ORIGINS IN THE PLAINS OF CENTRAL CANADA...WILL SWEEP THROUGH THE UPPER OHIO VALLEY WITH SHOWERS WEDNESDAY. REGARDING TEMPERATURES...LOWS MONDAY NIGHT CAN BE NEARLY AS COLD THIS COMING NIGHT...SO ITS POSSIBLE THERE CAN BE PATCHES OF FROST. HOWEVER...WILL NOT ADDRESS THIS SCENARIO UNTIL THE EXTENT OF TONIGHTS FREEZE ON THE GROWING SEASON CAN BE ASSESSED. PER RECENT GFS MOS AND SREF MEAN VALUES...HIGHS TUESDAY AND LOWS TUESDAY NIGHT CAN BE NEAR NORMAL. WEDNESDAYS HIGHS WILL BE RESTRICTED BY CLOUDS, SHOWERS, AND RENEWED COLD ADVECTION...AND SO CAN BE MORE LIKE 5 TO 8 DEGREES COLDER THAN NORMAL. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... HIGH PRESSURE THEN TAKES OVER ACROSS THE SOUTHEASTERN UNITED STATES WEDNESDAY NIGHT IN ADVANCE OF A WEAK COLD FRONT MOVING THROUGH ON FRIDAY. DOES NOT APPEAR TO BE MUCH MOISTURE WITH THE FRONT ITSELF...BUT FEEL THAT SLIGHT CHANCE POPS ARE PRUDENT CONSIDERING POSSIBLE LAKE INFLUENCE. HIGH PRESSURE THEN MOVES IN ONCE AGAIN...DROPPING ACROSS THE GREAT LAKES. LOTS OF UNCERTAINTY WITH LOW PRESSURE DEVELOPING IN THE PLAINS FOR THE WEEKEND...BUT SHOULD BE ABLE TO SWING SOME CHANCE POPS LATE SATURDAY. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGHOUT THE EXTENDED PERIOD. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... HIGH PRESSURE WILL PROVIDE VFR CONDITIONS EARLY WITH INCREASING MID AND HIGH CLOUDS. WITH AN UPPER LEVEL WAVE PASSING THROUGH DAYTIME SUNDAY...EXPECT A RETURN OF LOWER VFR CIGS THROUGHOUT THE DAY. EXPECT LIGHT RAIN TO DEVELOP BY MIDDAY SPREADING NORTHWARD IN THE AFTERNOON BUT EXPECT VFR TO CONTINUE. .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL CLEAN OUT CIGS SUNDAY EVENING WITH LIGHT WINDS. VFR CONDITIONS THROUGH MUCH OF THE OUTLOOK PERIOD. THE EXCEPTION WILL BE WEDNESDAY...WHEN A COLD FRONT WILL BRING RESTRICTIONS IN SHOWERS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 2 AM TO 9 AM EDT MONDAY FOR MDZ001. OH...FREEZE WARNING FROM 2 AM TO 9 AM EDT MONDAY FOR OHZ039>041- 048>050-057>059-068-069. PA...FREEZE WARNING FROM 2 AM TO 9 AM EDT MONDAY FOR PAZ007>009- 013>016-020>023-029-031-073>076. WV...FREEZE WARNING FROM 2 AM TO 9 AM EDT MONDAY FOR WVZ001>004-012- 021>023-041. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
720 AM EDT SUN OCT 7 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 503 AM EDT SUN OCT 7 2012 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW FULL LATITUDE UPR TROF OVER ERN NAMERICA...WITH NW FLOW ALF OVER THE UPR GRT LKS. WITH H85 TEMPS ARND -7C OVER LK SUP /VS WATER TEMPS RANGING FM 6-7C OVER THE W TO 11-12C OVER THE E/...A WEAK SHRTWV MOVING THRU THE UPR LKS...AND ADEQUATE LLVL MSTR PER THE 00Z APX RAOB...SOME LK EFFECT -SHRA MIXED WITH SN CONTINUE OVER MAINLY THE E HALF OF THE LK WHERE INSTABILITY REMAINS GREATEST. PERSISTENT CNVGC SHOWN BY WIND OBS OVER THE E HALF OF THE LAKE ARE ALSO HELPING TO MAINTAIN THE COVERAGE/INTENSITY OF THIS PCPN IN THAT AREA. OVER THE W...MORE ACYC LLVL FLOW ASSOCIATED WITH SFC RDG EXTENDING FM HI CENTER IN THE SCNTRL PLAINS TOWARD THE UPR MIDWEST...COOLER WATERS...AS WELL AS SOMEWHAT DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB ARE CONSPIRING TO LIMIT THE ACTIVITY OVER THAT PART OF THE LAKE. ALTHOUGH DRIER AIR OVER THE NRN PLAINS PER THE 00Z BISMARCK RAOB IS SHIFTING TO THE E IN THE WLY FLOW ON THE NRN FLANK OF THE HI CENTER IN THE SCNTRL PLAINS...THERE IS A GOOD DEAL OF MID/HI CLD EXTENDING FM ARND LK WINNIPEG INTO THE NRN PLAINS ASSOCIATED WITH ISENTROPIC ASCENT ON THE 290-295K SFCS /H7-575/. TODAY...SHORT TERM MODELS ARE IN GOOD AGREEMENT SHOWING LARGER SCALE FLOW OVER THE ENTIRE CWA SHIFTING TO THE W AS HI PRES OVER THE SCNTRL PLAINS SHIFTS TOWARD THE OH RIVER VALLEY...WHICH SHOULD WEAKEN THE LLVL CNVGC NOW PRESENT OVER THE E HALF AND ADVECT WARMER H85 TEMPS/DRIER LLVL AIR TO THE W OVER THE CWA. THESE TRENDS WL TEND TO STEADILY WEAKEN THE ONGOING LK EFFECT PCPN NOW IMPACTING MAINLY THE E HALF OF THE CWA. THE ARRIVAL OF THE DRIER AIR WL ALSO RESULT IN MORE SUNSHINE...WHICH WL BE DIMMED AT TIMES BY THE BKN HIER CLDS DRIFTING INTO THE AREA FM THE NW. MIXING TO H8 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS MAINLY 45-50...EXCEPT IN THE LO 50S WHERE THE INCRSG W WIND DOWNSLOPES OVER THE CENTRAL. SUN NGT...AS NEXT SHRTWV/SFC LO DIGS SEWD THRU SCNTRL CANADA TO NEAR LK WINNIPEG AND SFC HI PRES SHIFTS INTO THE OH RIVER VALLEY BY 12Z...A STRENGTHENING WSW FLOW WL DVLP OVER THE UPR LKS WITH H925 WINDS INCRSG UP TO 25-35 KTS BY 12Z MON. ALTHOUGH SOME MID/HI CLDS ASSOCIATED WITH THE ISENTROPIC ASCENT ON THE 290K SFC WL BE OVER THE UPR LKS...THESE CLDS WL BE RATHER THIN. PWATS AS LO AS 0.25-0.30 INCH INDICATE TEMPS WL STILL FALL FAIRLY SHARPLY OVER THOSE INTERIOR LOCATIONS ESPECIALLY OVER THE SCNTRL THAT CAN DECOUPLE BEFORE THE H925 FLOW STRENGTHENS TOO MUCH OVERNGT. LOCATIONS NEAR LK SUP SHOULD BE WARMEST WITH DOWNSLOPE FLOW. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 503 AM EDT SUN OCT 7 2012 BY MONDAY MORNING THE UPPER GREAT LAKES WILL BE COMPLETELY WITHIN A LARGE 500MB TROUGH THAT WILL ENCOMPASS ALL BUT THE FAR SW CORNER OF THE NATION...EXTENDING FROM THE MAIN LOW OVER N CANADA THROUGH HUDSON BAY. FCST MODELS AGREE WITH THE ENHANCEMENT IN THE MAIN THROUGH SET UP FROM S HUDSON BAY THROUGH CENTRAL SASKATCHEWAN BY MONDAY AFTERNOON...SHIFTING TO CENTRAL MN BY DAYBREAK TUESDAY...AND SLOWLY ACROSS LAKE SUPERIOR/UPPER MI TUESDAY. THE APEX OF THE TROUGH SHOULD BE ACROSS THE CENTER OF THE CWA BY AT 12Z WEDNESDAY...BEFORE PUSHING TO THE LOWER GREAT LAKES DURING THE DAY. THE PROGRESSIVELY S SINKING /RUN TO RUN COMPARISON OVER THE PAST COUPLE OF DAYS/ SFC LOW OVER S MANITOBA AND ND MONDAY MORNING WILL RESULT IN INCREASED SW WINDS ACROSS THE UPPER GREAT LAKES. THE TRACK OF THE SFC LOW IS STILL IN QUESTION...WITH THE 06/18Z RUN OF THE GFS AROUND 6HRS FASTER THAN THE NAM/ECMWF/CANADIAN SOLUTIONS. THE 07/00Z RUN OF THE GFS IS MUCH FARTHER TO THE N...BUT STILL TRACKING A BIT FAST. THE TRACK WILL LIKELY BRING THE SFC LOW OVER W-CENTRAL LAKE SUPERIOR BY 06Z TUESDAY...BEFORE SLIDING NE TO JAMES BAY BY 00Z WEDNESDAY. GIVEN THIS TRACK...THE STRONGEST WINDS WILL LIKELY BE AHEAD OF THE SYSTEM /OUT OF THE SW MONDAY THROUGH MONDAY EVENING/. TEMPERATURE WISE...INCREASED DOWNSLOPE S FLOW WILL BE COUNTERACTED SLIGHTLY BY ADDITIONAL CLOUD COVER MONDAY AFTERNOON NEAR LAKE SUPERIOR. N/NW FLOW WILL RETURN TUESDAY NIGHT BEHIND THE EXITING SFC LOW. 850MB TEMPS OF -5 TO -8C MAY NOT BE ENOUGH TO CREATE MUCH MORE THAN ENHANCED CLOUD COVER NEAR THE LAKE SUPERIOR SHORELINE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE NUDGING IN FROM THE CENTRAL PLAINS WEDNESDAY SHOULD HELP IN PUSHING MUCH OF THE LOW LEVEL MOISTURE TO OUR EAST. IT WILL NOT BE QUITE THAT SIMPLE THOUGH...WITH NW FLOW ALOFT AND A CONTINUATION OF SMALLER SCALE WAVES BRINGING IN ADDITIONAL MOISTURE. THURSDAY THROUGH FRIDAY... YET ANOTHER WAVE LOOKS TO SLIDE IN FROM THE NW THURSDAY OR THURSDAY NIGHT. THE 06/12Z ECMWF WAS APPROX 12 HRS SLOWER THAN THE 06/18Z RUN OF THE GFS WITH THIS WEAKER TROUGH. THE 07/00Z RUNS HAVE NEARLY CORRECTED THIS ISSUE...WITH ONLY MINOR DIFFERENCES. STILL HAVE W TO NW GALES TO 35KTS POSSIBLE OVER CENTRAL AND E LAKE SUPERIOR THURSDAY AFTERNOON AND EVENING. FRIDAY NIGHT THROUGH SATURDAY... HIGH PRESSURE WILL ATTEMPT TO BUILD IN AT 500MB...WITH LITTLE MORE THAN ZONAL FLOW BEING THE RESULT...AS THE NEXT LOW NEAR THE 4-CORNERS GETS SWEPT UP IN THE MAIN FLOW. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 719 AM EDT SUN OCT 7 2012 WITH SOME DAYTIME HEATING...EXPECT STRENGTHENING W WIND TO TURN GUSTY AT ALL 3 TAF SITES...ESPECIALLY AT THE MORE EXPOSED CMX LOCATION. DESPITE SOME INCRSG MID/HI CLDS...VFR CONDITIONS WL PREVAIL AT ALL 3 SITES WITH W WIND ADVECTING DRY LLVL AIR INTO THE UPR GRT LKS. PLAN ON SOME MARGINAL LLWS CONDITIONS TNGT WITH DVLPG RADIATION INVRN/DECOUPLING SFC WIND. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 503 AM EDT SUN OCT 7 2012 AS A HI PRES RIDGE BUILDS TOWARD THE OHIO RIVER VALLEY THRU TONIGHT AND LO PRES MOVES SE THRU CANADA TOWARD MINNESOTA...EXPECT A STRENGTHENING W WIND OVER LAKE SUPERIOR. AS IS TYPICAL FOR THIS FLOW...THE STRONGEST WINDS UP TO 30 KTS ARE MOST LIKELY IN THE AREA BETWEEN THE KEWEENAW AND ISLE ROYALE...WHERE SOME GALE FORCE GUSTS TO 35 KTS ARE POSSIBLE LATER TODAY. LOW PRESSURE NEARING FROM SOUTH CENTRAL CANADA WILL RESULT IN INCREASING SOUTHWESTERLY WINDS MONDAY /WITH S GALES TO 35KTS OVER PORTIONS OF E LAKE SUPERIOR MONDAY INTO MONDAY EVENING/. EXPECT THE LOW TO TRACK FROM ND AND SOUTHERN MANITOBA TO W LS BY LATE MONDAY AFTERNOON INTO MONDAY EVENING. THE LOW WILL PUSH NE TUESDAY...AS ANOTHER DRYING HIGH PRESSURE SYSTEM ATTEMPTS TO BUILD IN FROM THE CENTRAL PLAINS. GUSTS WILL DIMINISH TO 20-25KTS TUESDAY NIGHT. YET ANOTHER LOW SHOULD SKIRT ACROSS OR JUST NORTH OF LAKE SUPERIOR WEDNESDAY NIGHT...WITH WINDS BRIEFLY INCREASING WITH GUSTS NEARING 30KTS AGAIN WEDNESDAY OUT OF THE NW. HIGH PRESSURE SHOULD FINALLY WIN OUT TOWARD THE END OF THE WORK WEEK...WITH ANOTHER ROUND OF WEST TO NORTHWEST GALES TO 35KTS POSSIBLE THURSDAY AFTERNOON AND EVENING...IN BETWEEN NEARING HIGH PRESSURE TO OUR W AND EXITING LOW PRESSURE TO THE E. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR LSZ267. LAKE MICHIGAN... GALE WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING FOR LMZ248-250. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...KC MARINE...KC/KF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1001 AM EDT SUN OCT 7 2012 .SYNOPSIS... COOL AND DRY WEATHER IS EXPECTED THROUGH EARLY AFTERNOON. RAIN WILL OVERSPREAD THE AREA BY LATE TODAY BEFORE ENDING EARLY TONIGHT. OUR SKY WILL CLEAR OUT TONIGHT AND THIS MAY ALLOW FOR SOME AREAS OF FROST TO FORM BY EARLY MONDAY MORNING. MOSTLY DRY WEATHER IS EXPECTED MONDAY AND TUESDAY BEFORE OUR NEXT SHOT AT WIDESPREAD RAIN COMES WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... 10 AM UPDATE... HV UPDATED GRIDS TO RMV POPS ACRS THE FAVORED LK EFFECT LOCATIONS AS SHOWERS HV WEAKENED RAPIDLY THIS MRNG. HV ALSO RMVD SLGT CHC POPS OVR THE SE AFT 18Z AS AIRMASS WL LKLY TAKE AWHILE TO SATURATE DOWN, WITH MAINLY VIRGA EXPECTED BTWN 18Z-21Z. H5 TROF WL APPRCH FM THE WEST AFT 21Z, RESULTING IN WIDESPREAD PCPN BREAKING OUT ACRS THE CWA. HV TWEAKED HRLY T/TD GRIDS TO COME INTO LINE WITH CURRENT OBS. WL EVALUATE POTENTIAL FOR FROST/FREEZE TONIGHT WITH LATEST MODEL DATA. PREVIOUS DISCUSSIONS BLO... 700 AM UPDATE... THE BAND OF LAKE EFFECT RAIN EAST OF LAKE ONTARIO IS FINALLY SHOWING A SOUTHWARD PUSH WHILE WEAKENING RAPIDLY. WILL CONFINE CHANCE POPS TO NORTH CENTRAL ONEIDA COUNTY AND EXTREME NORTHERN ONONDAGA COUNTY THROUGH 15Z BEFORE KEEPING A DRY FORECAST. A DEVELOPING AREA OF RAIN OVER SOUTH CENTRAL PA STILL LOOKS TO SKIRT JUST SOUTHEAST OF OUR CWA BUT STILL FEEL SLIGHT CHANCE POPS PRUDENT FOR NEPA AS A BUFFER. STILL LOOKING AT THE MAIN THREAT OF RAIN TO COME AFTER 21Z TODAY WITH THE DISTURBANCE MOVING THROUGH IL. 430 AM UPDATE... TODAY....A BAND OF LAKE EFFECT RAIN CONTINUES ACROSS CENTRAL OSWEGO COUNTY AND NORTHERN ONEIDA COUNTY. THE BAND HAS ACTUALLY SHOWN SOME SIGNS OF BECOMING MORE HEALTHY AND HAS PENETRATED FARTHER INLAND IN JUST THE LAST HOUR. HIGHER RESOLUTION MODELS SUCH AS THE HRRR AND THE 4KM NAM WHICH WERE DOING WELL WITH THE PLACEMENT OF THE BAND LATE LAST NIGHT...ARE MUCH TOO WEAK AND TOO FAR SOUTH WITH THE BAND AS OF 09Z. BASED ON THIS CONTINUED TO KEEP HIGH CHANCE POPS ACROSS NORTHERN ONEIDA COUNTY THROUGH 12Z...BEFORE GRADUALLY SHOWING A WEAKENING TREND AS BOUNDARY LAYER WINDS DIMINISH (BAND RETREATS TOWARD LAKE) AND THE FLOW TURNS MORE INTO THE SOUTHWEST. EXPECT ACTIVITY TO DIE DOWN COMPLETELY IN OUR AREA BY 15Z. MEANWHILE FOR THE REST OF US INCREASING HIGH CLOUDS NOW ARE MORE OF A BARK THEN A BITE FOR OUR AREA WITH A UPPER LEVEL JET MOVING OVERHEAD NOW...BUT THE BEST LIFT BEING OFF TO OUR SOUTH AND EAST. KEPT SLIGHT CHANCE POPS IN FOR THE FAR SE CWA IN THE 15Z - 18Z TIME FRAME AS MOST OF THE MODEL GUIDANCE BRINGS POPS INTO INTO EASTERN PA AND NORTHERN NJ...BUT STAYING SOUTH OF THE REGION. A MUCH BETTER SHOT AT RAIN...WIDESPREAD FOR A FEW HOURS...WILL COME WITH A DISTURBANCE IN THE JET STREAM WINDS ALOFT NOW OVER WESTERN IL. RAIN CHANCES WILL INCREASE RAPIDLY BETWEEN 21Z AND 0Z WITH ALL BUT AREAS NORTH OF THE THRUWAY IN LIKELY TO CAT POPS...WITH CHANCE POPS FAR NORTH TONIGHT...RAIN QUICKLY ENDS BY 03Z ACROSS MOST OF THE CWA WITH SOME LAKE EFFECT ACTIVITY (RAIN) POSSIBLE AFTER 06Z UP NORTH. BIGGEST CONCERN HOWEVER IS THE POTENTIAL FOR FROST/FREEZE CONDITIONS. MAV/MET GUIDANCE IS SHOWING 30 AT KELM AND THIS HAS BEEN CONSISTENT OVER THE PAST 24 HOURS. DESPITE SUCH COLD MOS NUMBERS...ELECTED TO HOLD OFF ON ANY ADVISORIES OR WARNINGS AS CONFIDENCE IS NOT QUITE HIGH ENOUGH AT THE MOMENT. CONCERNS INCLUDE THE TIMING ON WHEN WE ACTUALLY CLEAR OUT AND WHETHER OR NOT WE FOG IN OR SEE LOW CLOUDS REDEVELOP GIVEN THE WET GROUND FROM THE RAIN LATER TODAY. WILL LET THE DAY SHIFT REEVALUATE ON ANY HEADLINES AND CONTINUE TO HIGHLIGHT IN THE HWO. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... 430 AM UPDATE... MONDAY/TUESDAY....HIGH PRESSURE MOVING OUT OF THE OHIO VALLEY SHOULD KEEP MOST OF THIS PERIOD DRY BUT MODEL TRENDS ARE POINTING TO SOME UNCERTAINTY STARTING TUESDAY. ANY LAKE SHOWERS EARLY MONDAY MORNING SHOULD QUICKLY DIMINISH WITH RISING HEIGHTS BY LATE MORNING. FROST/FREEZE CONDITIONS MAY BE POSSIBLE AGAIN MONDAY NIGHT...DEPENDING ON THE AMOUNT OF INCREASING CLOUD COVER WE MAY SEE ESPECIALLY FAR SOUTHEAST. THE MODELS SHOW ANOTHER AREA OF MOISTURE MOVING THROUGH THE MID- ATLANTIC STATES...VERY SIMILAR TO WHAT WILL MISS US EARLY TODAY...LATER MONDAY AND MONDAY NIGHT. AGAIN THE BEST LIFT APPEARS TO BE JUST SOUTH AND EAST OF US AND WILL KEEP OUR AREA DRY THROUGH MONDAY NIGHT. AS THIS MOISTURE SLIDES EAST...HIGH PRESSURE MENTIONED ABOVE WILL MOVE OFF THE COAST OF MAINE. THIS WILL HELP TO DEVELOP AN ONSHORE FLOW AND WILL BEGIN TO PUSH MOISTURE BACK TOWARD THE COAST STARTING TUESDAY....ESPECIALLY LATER IN THE DAY. THE GFS AND EURO HINT AT THIS...BUT KEEP PRECIP MAINLY FROM THE HUDSON VALLEY SOUTH AND EAST...WHILE THE NAM IS A BIT FARTHER WEST. FOR NOW WILL PLAY SLIGHT CHANCE POPS TUESDAY FOR LATER IN THE DAY INTO TUESDAY NIGHT GIVEN THE UNCERTAINTY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MEDIUM RANGE MODELS MAINTAIN SOME CONSISTENCY WITH INDICATIONS OF BEST SHOT OF PRECIPITATION ACROSS THE ENTIRE REGION DURING THIS PERIOD TO BE IN THE WEDNESDAY TIME FRAME. THIS IS THEN LIKELY TO BE FOLLOWED BY DEEPENING COLD AIR AND A MAINTAINED PRESENCE OF SHOWER CHANCES TO THE LEE OF LAKE ONTARIO THROUGH THURSDAY WITH IMPROVED WX OVER THE SOUTHERN HALF. ANOTHER WEAK UPPER TROF AND SFC FRONT MAY SPREAD A QUICK SHOT OF SHOWERS INTO THE AREA ON FRIDAY. A FAIRLY LARGE CENTER OF CONTINENTAL POLAR...FALL- LIKE...HIGH PRESSURE WORKS IN FOR AT LEAST THE FIRST HALF OF NEXT WEEKEND. FOLLOWED THE HPC DAY 3-7 GUIDANCE CLOSELY WITH ONLY MINOR LOCAL ADJUSTMENTS TO TEMPERATURES. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... 7 AM UPDATE... MVFR CIGS POSSIBLE NEXT HOUR OR SO AT KRME DUE TO LAKE CLOUDS OTHERWISE VFR THROUGH THIS AFTERNOON. HIGH CLOUDS AROUND 15KFT LOWER TO 5KFT BY 20Z...WITH RAIN OVERSPREADING THE SOUTHERN TERMINALS BY 22Z. UP NORTH SHOWERS POSSIBLE TOWARD 0Z...BUT NOT AS LIKELY AS FARTHER SOUTH AND WILL ONLY COVER WITH A TEMPO GROUP. ACROSS THE SOUTHERN TERMINALS...MVFR CIGS AND PERHAPS VSBYS...APPEAR MOST LIKELY ABOUT 1 TO 2 HOURS AFTER THE ONSET OF THE RAIN AND WILL PLAY AS A TEMPO GROUP THROUGH 04Z. LATER TONIGHT THE TERMINALS WILL BEGIN TO CLEAR OUT. BASED ON THE TIMING OF THE CLEARING...MVFR TO IFR CIGS AND VSBYS POSSIBLE EVERYWHERE EXCEPT AT KSYR/KRME DUE TO VALLEY OR LOW STRATUS. MOST CONFIDENT AT KELM. NW WINDS OVERNIGHT 5 KTS OR LESS THROUGH THIS MORNING...THEN SW FLOW LATER TODAY 5-10 KTS BECMG NWLY ACRS CNTRL NY LATE AFTERNOON. NORTHWEST WINDS AROUND 5 KTS TONIGHT. OUTLOOK... MON TO TUE...VFR. WED...VFR/MVFR. SOME SHOWERS. THU...VFR. SOME LAKE EFFECT RAIN SHOWERS NORTH. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...HEDEN/PVN NEAR TERM...HEDEN/PVN SHORT TERM...HEDEN LONG TERM...JAB AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
709 AM EDT SUN OCT 7 2012 .SYNOPSIS... LAKE EFFECT RAIN SHOWERS WILL BE POSSIBLE EARLY THIS MORNING ACROSS CENTRAL NEW YORK...OTHERWISE DRY WEATHER IS EXPECTED THROUGH EARLY AFTERNOON. RAIN WILL OVERSPREAD THE AREA BY LATE TODAY BEFORE ENDING EARLY TONIGHT. OUR SKY WILL CLEAR OUT TONIGHT AND THIS MAY ALLOW FOR SOME AREAS OF FROST TO FORM BY EARLY MONDAY MORNING. MOSTLY DRY WEATHER IS EXPECTED MONDAY AND TUESDAY BEFORE OUR NEXT SHOT AT WIDESPREAD RAIN COMES WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... 700 AM UPDATE... THE BAND OF LAKE EFFECT RAIN EAST OF LAKE ONTARIO IS FINALLY SHOWING A SOUTHWARD PUSH WHILE WEAKENING RAPIDLY. WILL CONFINE CHANCE POPS TO NORTH CENTRAL ONEIDA COUNTY AND EXTREME NORTHERN ONONDAGA COUNTY THROUGH 15Z BEFORE KEEPING A DRY FORECAST. A DEVELOPING AREA OF RAIN OVER SOUTH CENTRAL PA STILL LOOKS TO SKIRT JUST SOUTHEAST OF OUR CWA BUT STILL FEEL SLIGHT CHANCE POPS PRUDENT FOR NEPA AS A BUFFER. STILL LOOKING AT THE MAIN THREAT OF RAIN TO COME AFTER 21Z TODAY WITH THE DISTURBANCE MOVING THROUGH IL. THE PREVIOUS AFD IS BELOW... 430 AM UPDATE... TODAY....A BAND OF LAKE EFFECT RAIN CONTINUES ACROSS CENTRAL OSWEGO COUNTY AND NORTHERN ONEIDA COUNTY. THE BAND HAS ACTUALLY SHOWN SOME SIGNS OF BECOMING MORE HEALTHY AND HAS PENETRATED FARTHER INLAND IN JUST THE LAST HOUR. HIGHER RESOLUTION MODELS SUCH AS THE HRRR AND THE 4KM NAM WHICH WERE DOING WELL WITH THE PLACEMENT OF THE BAND LATE LAST NIGHT...ARE MUCH TOO WEAK AND TOO FAR SOUTH WITH THE BAND AS OF 09Z. BASED ON THIS CONTINUED TO KEEP HIGH CHANCE POPS ACROSS NORTHERN ONEIDA COUNTY THROUGH 12Z...BEFORE GRADUALLY SHOWING A WEAKENING TREND AS BOUNDARY LAYER WINDS DIMINISH (BAND RETREATS TOWARD LAKE) AND THE FLOW TURNS MORE INTO THE SOUTHWEST. EXPECT ACTIVITY TO DIE DOWN COMPLETELY IN OUR AREA BY 15Z. MEANWHILE FOR THE REST OF US INCREASING HIGH CLOUDS NOW ARE MORE OF A BARK THEN A BITE FOR OUR AREA WITH A UPPER LEVEL JET MOVING OVERHEAD NOW...BUT THE BEST LIFT BEING OFF TO OUR SOUTH AND EAST. KEPT SLIGHT CHANCE POPS IN FOR THE FAR SE CWA IN THE 15Z - 18Z TIME FRAME AS MOST OF THE MODEL GUIDANCE BRINGS POPS INTO INTO EASTERN PA AND NORTHERN NJ...BUT STAYING SOUTH OF THE REGION. A MUCH BETTER SHOT AT RAIN...WIDESPREAD FOR A FEW HOURS...WILL COME WITH A DISTURBANCE IN THE JET STREAM WINDS ALOFT NOW OVER WESTERN IL. RAIN CHANCES WILL INCREASE RAPIDLY BETWEEN 21Z AND 0Z WITH ALL BUT AREAS NORTH OF THE THRUWAY IN LIKELY TO CAT POPS...WITH CHANCE POPS FAR NORTH TONIGHT...RAIN QUICKLY ENDS BY 03Z ACROSS MOST OF THE CWA WITH SOME LAKE EFFECT ACTIVITY (RAIN) POSSIBLE AFTER 06Z UP NORTH. BIGGEST CONCERN HOWEVER IS THE POTENTIAL FOR FROST/FREEZE CONDITIONS. MAV/MET GUIDANCE IS SHOWING 30 AT KELM AND THIS HAS BEEN CONSISTENT OVER THE PAST 24 HOURS. DESPITE SUCH COLD MOS NUMBERS...ELECTED TO HOLD OFF ON ANY ADVISORIES OR WARNINGS AS CONFIDENCE IS NOT QUITE HIGH ENOUGH AT THE MOMENT. CONCERNS INCLUDE THE TIMING ON WHEN WE ACTUALLY CLEAR OUT AND WHETHER OR NOT WE FOG IN OR SEE LOW CLOUDS REDEVELOP GIVEN THE WET GROUND FROM THE RAIN LATER TODAY. WILL LET THE DAY SHIFT REEVALUATE ON ANY HEADLINES AND CONTINUE TO HIGHLIGHT IN THE HWO. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... 430 AM UPDATE... MONDAY/TUESDAY....HIGH PRESSURE MOVING OUT OF THE OHIO VALLEY SHOULD KEEP MOST OF THIS PERIOD DRY BUT MODEL TRENDS ARE POINTING TO SOME UNCERTAINTY STARTING TUESDAY. ANY LAKE SHOWERS EARLY MONDAY MORNING SHOULD QUICKLY DIMINISH WITH RISING HEIGHTS BY LATE MORNING. FROST/FREEZE CONDITIONS MAY BE POSSIBLE AGAIN MONDAY NIGHT...DEPENDING ON THE AMOUNT OF INCREASING CLOUD COVER WE MAY SEE ESPECIALLY FAR SOUTHEAST. THE MODELS SHOW ANOTHER AREA OF MOISTURE MOVING THROUGH THE MID- ATLANTIC STATES...VERY SIMILAR TO WHAT WILL MISS US EARLY TODAY...LATER MONDAY AND MONDAY NIGHT. AGAIN THE BEST LIFT APPEARS TO BE JUST SOUTH AND EAST OF US AND WILL KEEP OUR AREA DRY THROUGH MONDAY NIGHT. AS THIS MOISTURE SLIDES EAST...HIGH PRESSURE MENTIONED ABOVE WILL MOVE OFF THE COAST OF MAINE. THIS WILL HELP TO DEVELOP AN ONSHORE FLOW AND WILL BEGIN TO PUSH MOISTURE BACK TOWARD THE COAST STARTING TUESDAY....ESPECIALLY LATER IN THE DAY. THE GFS AND EURO HINT AT THIS...BUT KEEP PRECIP MAINLY FROM THE HUDSON VALLEY SOUTH AND EAST...WHILE THE NAM IS A BIT FARTHER WEST. FOR NOW WILL PLAY SLIGHT CHANCE POPS TUESDAY FOR LATER IN THE DAY INTO TUESDAY NIGHT GIVEN THE UNCERTAINTY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MEDIUM RANGE MODELS MAINTAIN SOME CONSISTENCY WITH INDICATIONS OF BEST SHOT OF PRECIPITATION ACROSS THE ENTIRE REGION DURING THIS PERIOD TO BE IN THE WEDNESDAY TIME FRAME. THIS IS THEN LIKELY TO BE FOLLOWED BY DEEPENING COLD AIR AND A MAINTAINED PRESENCE OF SHOWER CHANCES TO THE LEE OF LAKE ONTARIO THROUGH THURSDAY WITH IMPROVED WX OVER THE SOUTHERN HALF. ANOTHER WEAK UPPER TROF AND SFC FRONT MAY SPREAD A QUICK SHOT OF SHOWERS INTO THE AREA ON FRIDAY. A FAIRLY LARGE CENTER OF CONTINENTAL POLAR...FALL- LIKE...HIGH PRESSURE WORKS IN FOR AT LEAST THE FIRST HALF OF NEXT WEEKEND. FOLLOWED THE HPC DAY 3-7 GUIDANCE CLOSELY WITH ONLY MINOR LOCAL ADJUSTMENTS TO TEMPERATURES. && .AVIATION /11Z SUNDAY THROUGH THURSDAY/... 7 AM UPDATE... MVFR CIGS POSSIBLE NEXT HOUR OR SO AT KRME DUE TO LAKE CLOUDS OTHERWISE VFR THROUGH THIS AFTERNOON. HIGH CLOUDS AROUND 15KFT LOWER TO 5KFT BY 20Z...WITH RAIN OVERSPREADING THE SOUTHERN TERMINALS BY 22Z. UP NORTH SHOWERS POSSIBLE TOWARD 0Z...BUT NOT AS LIKELY AS FARTHER SOUTH AND WILL ONLY COVER WITH A TEMPO GROUP. ACROSS THE SOUTHERN TERMINALS...MVFR CIGS AND PERHAPS VSBYS...APPEAR MOST LIKELY ABOUT 1 TO 2 HOURS AFTER THE ONSET OF THE RAIN AND WILL PLAY AS A TEMPO GROUP THROUGH 04Z. LATER TONIGHT THE TERMINALS WILL BEGIN TO CLEAR OUT. BASED ON THE TIMING OF THE CLEARING...MVFR TO IFR CIGS AND VSBYS POSSIBLE EVERYWHERE EXCEPT AT KSYR/KRME DUE TO VALLEY OR LOW STRATUS. MOST CONFIDENT AT KELM. NW WINDS OVERNIGHT 5 KTS OR LESS THROUGH THIS MORNING...THEN SW FLOW LATER TODAY 5-10 KTS BECMG NWLY ACRS CNTRL NY LATE AFTERNOON. NORTHWEST WINDS AROUND 5 KTS TONIGHT. OUTLOOK... MON TO TUE...VFR. WED...VFR/MVFR. SOME SHOWERS. THU...VFR. SOME LAKE EFFECT RAIN SHOWERS NORTH. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...HEDEN NEAR TERM...HEDEN SHORT TERM...HEDEN LONG TERM...JAB AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
740 AM EDT SUN OCT 7 2012 .SYNOPSIS... A COLD FRONT OVER THE AREA WILL MOVE SOUTHEAST TO COASTAL SECTIONS THIS MORNING. THE FRONT WILL BRIEFLY STALL OVER THE COASTAL AREAS TODAY... BEFORE SHIFTING OFFSHORE THIS EVENING. THICK CLOUD COVER AND A CHILLY AIR MASS WILL HOLD OVER THE REGION THROUGH MONDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 300 AM SUNDAY... EARLY MORNING... THE SURFACE COLD FRONT HAS PUSHED SOUTH THROUGH THE AREA SINCE LAST EVENING...NOW STRETCHING FROM KGSP TO KMEB TO KPGV. A PATCH OF SHOWERS MOVING NORTHEAST BETWEEN KGSO AND KRDU IS BEING AIDED BY A WEAK DISTURBANCE LOFT IN WATER VAPOR AND INCREASING ISENTROPIC ASCENT. THE 00Z KGSO RAOB SHOWERS ENOUGH INSTABILITY ABOVE THE STRENGTHENING COLD DOME TO SUPPORT AT LEAST A FEW SPORADIC LIGHTNING STRIKES THROUGH EARLY MORNING. THE HEAVIER SHOWERS A PRODUCING BETWEEN ONE TO TWO TENTHS OF AN INCH OF RAINFALL. BASED ON RAP ISENTROPIC FIELDS AND HRRR SIMULATED REFLECTIVITY...EXPECT THESE SHOWERS TO CONTINUE MOVING OFF TO THE NORTHEAST AND OUT OF THE NORTHERN PIEDMONT/COASTAL PLAIN BY 10Z. TODAY... A SHORTWAVE CURRENTLY APPROACHING THE MID MS VALLEY REGION WILL SWING ACROSS THE OH VALLEY REGION THIS AFTERNOON..WITH PRECIP SPREADING EAST AND EXPANDING ALONG THE 850MB FRONT THAT HAS STALLED FROM THE LOWER TN VALLEY TO THE MID ATLANTIC STATES. WHILE THE FLOW AHEAD OF THE SHORTWAVE WILL STRENGTHEN THIS AFTERNOON...WINDS IN THE 295-305K LAYER STAY RELATIVELY PARALLEL TO FRONTAL ZONE AND CROSS-SECTIONS SHOW MUCH DEEPER MOISTURE ALONG AND WEST OF THE MOUNTAINS. THUS...WHILE OVERCAST SKIES WILL DEVELOP THIS MORNING DUE TO MOISTENING AT THE TOP OF THE STABLE LAYER...PRECIP AMOUNTS SHOULD BE RELATIVELY LIGHT..WITH MODELS NOW ONLY SHOWING A TENTH OF AN INCH OR LESS IN THE NORTHWEST PIEDMONT. TO THE SOUTH AND EAST...THE COLD FRONT WILL STALL ACROSS SC AND SOUTHEAST NC THIS MORNING. A WEAK WAVE OF LOW PRESSURE IS FORECAST TO MOVE FROM CENTRAL NC TOWARD THE OBX THIS AFTERNOON...WHICH SHOULD HELP TRIGGER SOME SHOWERS AND STORMS IN THE VICINITY OF THE FRONTAL ZONE. FORECAST SOUNDINGS AT KFAY LOOK MUCH TOO STABLE FOR ANY NEAR SURFACE BASED CONVECTION...BUT MUCAPE FORECASTS SHOW AROUND 400-600 J/KG JUST TO THE NORTH OF THE FRONT...SO AN ISOLATED AND ELEVATED STORM COULD BE POSSIBLE OVER THE SOUTHEAST CWA. HOWEVER...THE COLD FRONT IS FORECAST TO SURGE FURTHER SOUTH AND EAST AFTER 18Z (IN THE WAKE OF THE SURFACE WAVE)...WITH THE POTENTIAL FOR AN THUNDER BECOMING LESS LIKELY WITH TIME. THE POP FORECAST WILL SHOW A STRONG GRADIENT FROM 80 IN THE NORTHWEST TO 25 IN THE SOUTHEAST. THE RISE IN TEMPS TODAY WILL SOMEWHAT DEPEND ON HOW MUCH PRECIP FALLS...WITH LESS RISE EXPECTED IN THE NORTHWEST PIEDMONT WITH PERIODS OF RAIN EXPECTED THROUGH THIS AFTERNOON. THINNER MOISTURE PROFILES AND A LITTLE MORE HEATING NEAR THE FRONT MAY ALLOW FOR SOME LOWER 70S IN THE FAR SOUTHEASTERN AREAS. MID 50S TO LOWER 70S ARE EXPECTED WITH A SHARP GRADIENT ACROSS THE PIEDMONT. TONIGHT AND MONDAY... AS HIGH PRESSURE EXPANDS ACROSS THE OHIO VALLEY TONIGHT...COOL AND DRIER LOW LEVEL AIR WILL WORK SOUTH INTO THE AREA WITH DEW POINTS FALLING INTO THE 40S CWA-WIDE. THIS WILL ALLOW FOR A LITTLE MORE COOLING AND LOWS REACHING THE 42-49 RANGE AND NO RAIN OVERNIGHT. ANOTHER SHORTWAVE OVER CO/WY THIS MORNING WILL SWING FURTHER SOUTH TOWARD THE TN VALLEY MONDAY...WITH A LITTLE BETTER RAIN CHANCES OVER ALL OF CENTRAL NC AS THE 850MB DRIFTS EASTWARD AND THE RIGHT ENTRANCE REGION OF THE PERSISTENT UPPER JET TO OUR NORTH SHIFTS OVERHEAD. ISENTROPIC ASCENT...WHILE STRONGER...IS STILL NOT VERY IMPRESSIVE...SO RAINFALL TOTALS MAY AGAIN BE LIGHT. HOWEVER... TEMPS WILL LIKELY NOT RISE MUCH AT ALL ACROSS THE CWA AS A BETTER COLD AIR DAMMING AIRMASS DEVELOPS...WITH MOST GUIDANCE INDICATING LOW TO MID 50S...POSSIBLY 60 IN THE FAR SOUTHEAST. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... AS OF 220 AM SUNDAY... FOR MONDAY NIGHT: PATTERN REMAINS DOMINATED BY FAST MID LEVEL CYCLONIC FLOW... ON THE COLD SIDE OF A SURFACE BOUNDARY... RESULTING IN CHILLY AND HIGHLY UNSETTLED WEATHER. THE PARENT HIGH SUPPORTING THE DAMMING REGIME WILL BE CENTERED OVER THE COAST OF MAINE AND CANADIAN MARITIMES WHILE EXTENDING TO THE SW... THROUGH THE NC FOOTHILLS AND WRN PIEDMONT. MOIST UPGLIDE AT 290K-295K IS NOT PARTICULARLY INTENSE OVER CENTRAL NC BUT THE PRESENCE OF A DEEP NEARLY SATURATED LAYER AT 950 MB TO 750 MB SHOULD MAKE THIS LIFT VERY PRODUCTIVE IN TERMS OF CONDENSATION AND PRECIP... AND THE FAST-MOVING PASSAGE OF A MID LEVEL WAVE THROUGH THE AREA SHOULD FURTHER AUGMENT LIFT. UPPER DIVERGENCE OVER CENTRAL NC... IN THE RIGHT ENTRANCE REGION OF THE 120+ KT UPPER JET CORE OVER AND JUST OFF THE NORTHEAST COAST ON MONDAY... QUICKLY DIMINISHES AS THE JET MOVES AWAY TO THE NE... AND FORECAST SOUNDINGS CONFIRM DRYING ALOFT OVERNIGHT... HOWEVER THE COLUMN WILL REMAIN NEARLY SATURATED BELOW 750 MB WITH LOWERING CEILINGS OVERNIGHT WITHIN THE PERSISTENT DAMMING-INDUCED STABLE LAYER. THE MOIST UPGLIDE LARGELY ENDS AFTER MIDNIGHT... AS THE WINDS ALOFT DECELERATE AND THE MID LEVEL WAVE EXITS ALONG WITH THE UPPER JET-RELATED FORCING FOR ASCENT. EXPECT A GRADUAL LOWERING OF LIGHT RAIN AND DRIZZLE COVERAGE FROM SOUTH TO NORTH THROUGH THE NIGHT... ENDING LAST IN THE FAR NORTHWEST CWA (ROXBORO THROUGH THE TRIAD) WHERE SLOPED ASCENT WILL LINGER ALONG A WEAK 925 MB FRONTAL ZONE. LOW CLOUDS... AREAS OF FOG... AND POCKETS OF DRIZZLE ARE LIKELY TO PERSIST AREAWIDE THROUGH DAYBREAK. TEMPS SHOULD DROP NO MORE THAN 10 DEGREES OR SO FROM THE PRECEDING CHILLY DAYTIME TEMPS... YIELDING LOWS OF 42-49. FOR TUESDAY/TUESDAY NIGHT: THE MID LEVEL CANADIAN VORTEX WOBBLES OVER HUDSON BAY WHILE ITS TRAILING BROAD TROUGHING SHIFTS SLOWLY FROM THE UPPER MIDWEST TOWARD MI WHILE AMPLIFYING. THE STRONG (ROUGHLY 1030 MB) PARENT SURFACE HIGH CENTERED OVER NOVA SCOTIA EARLY TUESDAY CONTINUES MOVING NORTHEAST OVER THE MARITIMES... CAUSING THE TRAILING RIDGE TO LOSE ITS GRIP ON CENTRAL NC AND LEAVE BEHIND A DISCONNECTED WEAK RESIDUAL COOL STABLE POOL. THIS SEPARATION FROM THE SUPPLY OF COOL DRY AIR TO MAINTAIN THE DAMMING AIR MASS WILL ALLOW IT TO BECOME VULNERABLE TO HORIZONTAL DISPERSION AND CONVECTIVE MIXING AS THE DRIER AIR ALOFT ALLOWS STRONG HEATING FROM THE TOP... ALTHOUGH TYPICALLY THIS EROSION PROCESS OFTEN TAKES QUITE A WHILE PARTICULARLY WITH A STABLE LAYER THIS DEEP. WILL BE SLOW TO GET RID OF THE WEDGE-SUPPORTED CLOUDS ON TUESDAY... TRENDING GRADUALLY TO PARTLY CLOUDY LATE IN THE DAY. THE WEAK HIGH WILL DRIFT BACK TOWARD THE SW TO OVER THE INTERIOR SOUTHEAST STATES TUESDAY NIGHT... AND WITH THE RESULTING MODIFICATION OF THE AIR MASS... THICKNESSES WILL START TO REBOUND BUT SHOULD STILL HOLD WELL BELOW NORMAL FOR ANOTHER DAY GIVEN THE DELAYED HEATING. EXPECT MODEST WARMING WITH HIGHS OF 60-68. EXPECT FAIR SKIES TUESDAY NIGHT WITH CONTINUED DRYING ALOFT... ALTHOUGH RECOVERING SURFACE DEW POINTS COMBINED WITH LIGHT WINDS IS LIKELY TO LEAD TO DEVELOPMENT OF GROUND FOG OVERNIGHT. LOWS 47-52. -GIH && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 250 AM SUNDAY... EXPECT GENERALLY DRY WEATHER BUT WITH ROLLER COASTER TEMPS AS A SUCCESSION OF FRONTS DROPS THROUGH THE REGION. FOR WEDNESDAY/WEDNESDAY NIGHT: THE MID LEVEL TROUGH AXIS SWINGS SWIFTLY ENE THROUGH THE GREAT LAKES AND NORTHEAST STATES... DRAGGING A SURFACE COLD FRONT THROUGH CENTRAL NC WEDNESDAY AFTERNOON. GIVEN THAT THE SURFACE HIGH CENTER WILL BE LOCATED TO OUR SOUTH AND SW... THERE WILL BE LITTLE TO NO MOISTURE FLUX AHEAD OF THE FRONT... THUS IT SHOULD COME THROUGH DRY. THICKNESSES ARE PROJECTED TO BE AT OR JUST ABOVE NORMAL WEDNESDAY... TRANSLATING TO HIGHS IN THE MID TO UPPER 70S. YUKON-SOURCE HIGH PRESSURE BUILDING IN BEHIND THE FRONT SHOULD SEND THICKNESSES PLUNGING BACK DOWN BELOW NORMAL... WITH LOWS IN THE MID 40S TO NEAR 50. FOR THURSDAY THROUGH SATURDAY: THE SURFACE HIGH IS EXPECTED TO BUILD OVER NC ON THURSDAY... WITH BROAD/FAST/CYCLONIC MID LEVEL FLOW FROM SW CANADA ACROSS THE NORTHEAST STATES. FAIR AND DRY THURSDAY WITH INITIALLY COOL BUT MODERATING TEMPS. A MINOR WAVE DROPS INTO THE LONGWAVE TROUGH OVER THE GREAT LAKES... AND THIS ACCOMPANYING SURFACE COLD FRONT WILL APPROACH NC FROM THE NNW ON FRIDAY. ONCE AGAIN... VERY LITTLE MOISTURE IS AVAILABLE AHEAD OF AND ALONG THE FRONT AND LIFT WILL BE WEAK... SO EXPECT NO MORE THAN ISOLATED SHOWERS AT BEST. TEMPS SHOULD BOUNCE BACK UP TO NEAR NORMAL AHEAD OF THE FRONT FRIDAY. YET ANOTHER COOL HIGH BUILDS IN BEHIND THE FRONT FROM THE NORTH... ITS CENTER MOVING FROM OVER SW MI TO OFF THE NJ/DELMARVA COAST FROM FRIDAY EVENING THROUGH SATURDAY AS IT RIDGES SOUTHWARD THROUGH CENTRAL NC. EXPECT A SLIGHT COOLDOWN OF AROUND A CATEGORY FOR SATURDAY... WITH CONTINUED DRY WEATHER. -GIH && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 740 AM SUNDAY... A SMALL CLUSTER OF SHOWERS AND STORMS HAS DEVELOPED OVER SOUTHWESTERN NC AND IS MOVING RELATIVELY QUICKLY TO THE EAST ALONG A STALLED OUT COLD FRONT NEAR THE NC/SC BORDER. BRIEF HEAVY RAIN AND A GUST TO AROUND 30KT WITH THE HEAVIEST SHOWERS. NORTH OF THE FRONT...CEILINGS ARE GENERALLY MVFR WITH SOME IFR CONDITIONS REPORTED AT KGSO/KINT. THESE LOWER CEILINGS WILL PERSIST AT KINT/KGSO/KRDU/KRWI THROUGH THIS AFTERNOON...WITH SOME SCATTERING AND IMPROVEMENT POSSIBLE AT KFAY IS THE FRONT LIFTS BACK TO THE NORTH OF THE TERMINAL...AS RECENT MODEL RUNS SUGGEST. DRIER AIR IS EXPECTED TO FILTER INTO THE ARE THIS EVENING AND OVERNIGHT...LEADING TO A TEMPORARY IMPROVEMENT OF CEILINGS TO MVFR OR VFR. HOWEVER...ANOTHER DISTURBANCE ALOFT IS EXPECTED TO IMPACT THE AREA MONDAY...WITH WIDESPREAD MVFR/IFR CEILINGS TO REDEVELOP. OUTLOOK... LOW CEILINGS WILL LIKELY CONTINUE THROUGH AT LEAST TUESDAY...WITH IMPROVEMENT IN AVIATION CONDITIONS BY THE MIDDLE TO END OF THE WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...BLS SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...BLS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1008 AM CDT SUN OCT 7 2012 .DISCUSSION...THE 11Z HRRR AND 06Z GFS HAVE SPED UP THE TIMING OF A SHORTWAVE DIVING ACROSS SASKATCHEWAN TODAY AND INTO THE NORTHWESTERN CWA LATER THIS AFTERNOON. HOWEVER...THE SHORT RANGE MODELS PROG THIS ACTIVITY TO CROSS THE MT/ND BORDER AFTER 21Z TODAY. AS A RESULT...UPDATED THE FORECAST TO INDICATE DRY CONDITIONS AREAWIDE UNTIL 21Z...THEN INCREASED PRECIP CHANCES FOR THE EXTREME NORTHWEST AFTER 21Z. THE THERMAL PROFILES INDICATE THAT ANY PRECIP THAT DOES FALL SHOULD BE IN THE FORM OF ALL LIQUID. ALSO ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS TO ACCOUNT FOR THE CURRENT OBS/TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS WILL BE OUT SHORTLY. && .AVIATION...INCREASING VFR CLOUDINESS OVER WESTERN AND CENTRAL NORTH DAKOTA CAN BE EXPECTED AS WEAK WARM FRONT MOVES THROUGH. SOME WIND GUSTS WILL BE POSSIBLE THIS AFTERNOON IN HIGHER ELEVATIONS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TM...UPDATE HW...AVIATION
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
649 AM EDT SUN OCT 7 2012 .SYNOPSIS... MID/UPPER LEVEL WAVE STREAKS THROUGH TODAY. ANOTHER WAVE SKIRTS SOUTHERN AND EASTERN PORTIONS OF THE REGION MONDAY. A THIRD WAVE IS POSSIBLE MONDAY NIGHT INTO TUESDAY. COLD FRONT ON WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... 630AM UPDATE... FINESSED POPS THIS MORNING TO REFLECT QUICKER EXODUS OF -RA ACROSS MTNS...PER LATEST RUC AND UPSTREAM TRENDS ACROSS TN VALLEY. OTHERWISE NO OTHER CHANGES ATTM. PREVIOUS DISCUSSION BELOW... QUITE A CHALLENGING FCST IN THE NEAR TERM. FIRST ORDER OF BUSINESS IS UPR LVL SYS TDY...COUPLED WITH SFC WAVE RIDING ALONG STALLED OUT BOUNDARY TO S OF CWA. WEAK ECHOES NOTED CURRENTLY ON RADAR ACROSS SW VA AND WV MTNS...WITH SOMEWHAT HEAVIER PCPN ACROSS CUMBERLAND PLATEAU. MDL CONSENSUS IS FOR GENERALLY LIGHT QPF THIS MORNING ACROSS SW VA...EXTENDING UP THE WV MTNS WITH SFC WAVE. BEST ISENTROPIC LIFT LOOKS TO BE ALONG AND E OF THE EASTERN SLOPES AND THIS IS WHERE HIGHEST POPS WERE PLACED. STILL SOME QUESTION ABOUT HOW FAR WEST PCPN IS ABLE TO MAKE IT...GIVEN LACK OF GOOD ISENTROPIC LIFT AND STOUT LLVL DRY LYR. WILL ALLOW SCHC POPS TO EXTEND JUST W OF I79/US119 CORRIDOR...KEEPING WESTERN LOWLANDS AND SE OH DRY THIS MORNING. WILL WATCH FOR APPROACH OF S/W TROF THIS AFTN WHICH WILL HOOK UP WITH LINGERING MOISTURE OVER AREA FOR SCT SHRA ACROSS SE OH AND N HALF OF WV. HAVE THIS COVERED WITH SOME CHC POPS. SHOULD SEE SOME CLRING ACROSS NE KY...SW VA AND S WV LATE THIS AFTN. ROLLED WITH LATEST LAMP GUIDANCE FOR TEMPS TDY RESULTING IN UPR 40S TO LWR 50S OUTSIDE OF MTNS...WITH GENERALLY 40S IN HIGHER ELEVATIONS. KEPT A SMALL WINDOW THIS MORNING FOR A RA/SN MIX AT SNOWSHOE BUT THIS IS LOOKING DOUBTFUL AS MDLS HAVE COME IN SLIGHTLY WARMER. MAY STILL SEE SOME STRATOCU ACROSS SE OH AND N WV THIS EVE BEFORE TRYING TO DISSIPATE BY MIDNIGHT. HOWEVER...ANOTHER UPR LVL DISTURBANCE WILL BE QUICKLY APPROACHING IN BASE OF MEAN TROF. THIS SPELLS HEADACHES IN MINT FCST TONIGHT. MOS NUMBERS CONT TO COME IN ON THE COLD SIDE WITH GENERALLY LOW TO MID 30S OUTSIDE OF THE MTNS...WITH UPR 20S TO LWR 30S IN HIGH TERRAIN. HOWEVER...MDLS SHOW MID/HI CLDS QUICKLY STREAMING NE INTO THE AREA LATE TONIGHT...WITH GFS MOST BULLISH ON THIS. CRITICAL ARRIVAL TIME SLATED FOR 09-12Z. CIRRUS CURRENTLY ON GRAVEYARD SHIFT ALLOWED TEMPS TO SPIKE UPWARDS OF 5F AS IT MOVED IN...NOT HANDLED BY MDLS. ANOTHER FACTOR IS DRIER AIR IN FORM OF LWR DWPTS TRYING TO SNEAK INTO E OH WHICH WOULD RESULT IN TOO HIGH OF DWPT DEPRESSION FOR FROST SHOULD 32F OR LWR NOT BE ACHIEVED. REGARDLESS...TOO MUCH UNCERTAINTY TO MAKE ANY CHGS TO HEADLINES WITH THIS PACKAGE. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... MODELS ARE SHOWING A WAVE SKIRTING SOUTHEASTERN PORTIONS OF THE FORECAST AREA MONDAY. DIFFERENCES STILL EXIST ON HOW FAR NORTH THE PRECIPITATION WILL MAKE IT. WILL ADD SOME POPS IN THIS REGION BUT KEEP IN THE CHANCE CATEGORY DUE TO THE UNCERTAINTY. NAM IS SHOWING YET ANOTHER WAVE MONDAY NIGHT INTO TUESDAY. OTHER MODELS DO NOT HAVE THIS FEATURE CAUSING PRECIPITATION IN THE FORECAST AREA. LAST NIGHT NAM WAS FURTHER NORTH THAN OTHER MODELS WITH WAVE ON MONDAY...AND OTHER MODELS HAVE NOW TRENDED TOWARD THE NAM. THEREFORE...WILL GIVE THE NAM MORE WEIGHT THAN NORMAL IN THIS SITUATION AND ADD SOME SLIGHT CHANCE POPS. THIS ALSO EFFECTS TEMPERATURES AND FROST POTENTIAL. MODELS IN FAIRLY GOOD AGREEMENT WITH A COLD FRONT MOVING THROUGH ON WEDNESDAY. WILL ADJUST TIMING OF POPS SOME DUE TO SUCH GOOD AGREEMENT. && .LONG TERM /THURSDAY THROUGH SATURDAY/... THE GFS IS SHOWING A STRONG DEEP H5 TROUGH WITH STRONG ELONGATED VORT MAX AROUND ITS PERIPHERY ACROSS THE GREAT LAKES AND PA. THIS SYSTEM WILL BRING A COLD FRONT ACROSS SOUTHEAST OH AND WV WEDNESDAY. THE GFS/ECMWF CONTINUE TO SHOW PRESSURE GRADIENT TIGHTENING UP ON TUESDAY NIGHT/WEDNESDAY AHEAD OF A COLD FRONT. THIS SOUTHWEST FLOW WILL INCREASE H85 TEMPERATURES ABOUT 7 DEGREES CELSIUS BY 12Z WED. NOTICED NO MAJOR CHANGES FROM HPC GUIDANCE FROM PREVIOUS FCST. KEPT CHANCE POPS FOR WED AS WITH RAIN SHOWERS AND NO THUNDER. THESE CHANCE POPS WILL DIMINISH WED NIGHT...AND EXIT EAST TO THE NORTHEAST MOUNTAINS BY THURSDAY MORNING. MOISTURE LOOKS LIMITED ATTM...AND H85 TEMPERATURES REMAIN ABOVE FREEZING SUGGESTING ALL PCPN WILL FALL AS LIQUID. EXPECT BROAD AND DRY HIGH PRESSURE OVERHEAD THURSDAY FOR MOSTLY CLEAR SKIES...H85 TEMPS AROUND 9C PER GFS/ECMWF. ANOTHER BUT WEAKER AND LESS AMPLIFY H5 TROUGH WILL CROSS THE GREAT LAKES REGION FURTHER NORTH OUR AREA ON FRIDAY. MODELS SUGGEST A ANOTHER BUT WEAKER COLD FRONT WITH LIMITED MOISTURE COULD PRODUCE LOW CHANCES FRIDAY...WHILE A SOUTHERN STREAM SYSTEM LIFTS NORTHEAST WITH A POSSIBLE WARM FRONT UNDER SOUTHWEST FLOW NEXT SATURDAY. INTRODUCED CHANCE POPS SAT AND SAT NIGHT ACCORDINGLY. USED HPC GUIDANCE FOR TEMPS AS A BASED...TWEAKING UP TEMPS UNDER SOUTHWEST FLOW...AND DOWN DURING CLEAR NIGHTS. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... 12Z SUNDAY THROUGH 12Z MONDAY... AN UPR LVL DISTURBANCE WILL MOVE THROUGH TDY. BULK OF PRECIPITATION WITH THIS WILL BE MAINLY CONFINED TO SW VA AND THE WV MTNS...WITH CIGS GRADUALLY DETERIORATING TO MVFR...THEN IFR...ESPECIALLY ACROSS THE HIGHER TERRAIN AFTER 12 TO 15Z. ELSEWHERE...MID/HI CLDS WILL PREVAIL THRU MORNING. BY EARLY THIS AFTN THOUGH...CIGS MAY LWR INTO MVFR RANGE ACROSS SE OH AND N WV...TO INCLUDE KCRW...KPKB...AND KCKB AS UPR WAVE MOVES ACROSS. SHRA CHCS TOO LOW TO INCLUDE IN THOSE TAF SITES ATTM. BULK OF PRECIPITATION WILL BEGIN TO MOVE EAST OF THE AREA BY 18Z. FLIGHT CONDITIONS WILL IMPROVE TO MVFR BY 00Z AT MTN SITES AND KCKB...WITH A RETURN TO VFR CONDITIONS ACROSS REMAINDER OF AREA BY 21Z. SOME LINGERING LLVL MOISTURE IN FORM OF 4 TO 5 THSD FT STRATOCU MAY LINGER THIS EVE ACROSS THE MTNS. OTHERWISE SOME EVE CLEARING WILL GIVE WAY TO AN INCREASE ONCE AGAIN OF MID/HI CLDS BY 12Z MON...MAINLY ACROSS THE S. SOME MVFR FG POSSIBLE ACROSS RVR VALLEYS LATE. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF PRECIPITATION AND ONSET OF LOWER CIGS TODAY MAY VARY FROM FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY M H H H M H H H H M H H HTS CONSISTENCY H H H H H H H M H H H H BKW CONSISTENCY H M L M L L H H H M H M EKN CONSISTENCY H H H H M M M M H H H M PKB CONSISTENCY H H H H H H H M M M M H CKB CONSISTENCY H H H H H H H H H H H M AFTER 12Z MONDAY... IFR CIGS POSSIBLE MONDAY ACROSS HIGHER TERRAIN. .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZE WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR WVZ035>039-046-047. OH...FREEZE WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR OHZ066-067. KY...NONE. VA...NONE. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZE WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR WVZ035>039-046-047. OH...FREEZE WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR OHZ066-067. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/RPY/30 NEAR TERM...30 SHORT TERM...RPY LONG TERM...ARJ AVIATION...30
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
724 AM EDT SUN OCT 7 2012 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL TRACK ACROSS THE REGION FROM THE WEST AND OVER A LAYER OF COOLER AIR. THIS WILL RESULT IN A WET AND COOL DAY SUNDAY. MORE RAIN AND COOL TEMPERATURES ARE EXPECTED MONDAY AS ANOTHER UPPER LEVEL DISTURBANCE ENTERS FROM THE SOUTHWEST. BY TUESDAY...DRIER CONDITIONS WILL ARRIVE AND CONTINUE INTO THE LATER PART OF THE WEEK UNDER HIGH PRESSURE. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM EDT SUNDAY... WATER VAPOR SATELLITE IMAGERY INDICATES A WEAK SHORTWAVE ACROSS EASTERN KY INTO CENTRAL TN. THIS FEATURE IS IN ADVANCE OF A STRONGER UPPER LEVEL DISTURBANCE LOCATED ACROSS IOWA INTO MO. HRRR AND LOCAL WRF MODELS DEPICT THIS AREA OF RAIN WELL...UNDER THE RR QUAD OF A LIFTING UPPER LEVEL JET. WITH GOOD ISENTROPIC LIFT CONTINUING INTO EARLY AFTERNOON AND THE APPROACH OF MIDWESTERN UPPER LEVEL SHORTWAVE...PRECIP SHOULD EXPAND IN COVERAGE. AS A RESULT...WILL CONTINUE TO CARRY LIKELY POPS INTO THE EARLY AFTERNOON. BEHIND THIS SYSTEM...LOW LEVEL WINDS VEER TO THE NORTHWEST AND ISENTROPIC DOWNGLIDE BEINGS LATE THIS AFTERNOON/EARLY THIS EVENING...WHICH WILL GRADUALLY BRING AN END TO THE PRECIP. CLOUDS...WEAK CAA...AND PRECIP WILL KEEP TEMPERATURES FROM RISING MUCH AT ALL TODAY. IN FACT...TEMPS MAY DROP TODAY. THEREFORE...LEANED TOWARD THE COOLER MAV AND LOCALLY DERIVED MOS GUIDANCE FOR HIGHS TODAY. THE NEXT UPPER LEVEL SYSTEM ZIPPING INTO THE LOWER OHIO VALLEY BY LATE SUNDAY NIGHT/EARLY MONDAY MORNING WILL BACK LOW LEVEL WINDS AND SET UP A BAROCLINIC ZONE ACROSS THE SOUTHERN PORTION OF OUR FORECAST AREA LATE TONIGHT. THIS MAY GENERATE SOME LIGHT PRECIP IN THIS REGION...AND KEPT SMALL POPS HERE LATE TONIGHT. IN THE NORTH...THE THREAT FOR FROST APPEARS LOW WITH A WET GROUND/WARM SOIL TEMPS AND CLOUD COVER. IF ANY CLEARING CAN BE MAINTAINED...SOME PATCHY FROST IN THE DEEP MOUNTAIN VALLEYS FROM BURKES GARDEN INTO SOUTHEAST WV MAY DEVELOP. WITH THE INCREASE IN CLOUDS...USED A MAV/MET MIX FOR LOWS WHICH ARE CLOSE TO OUR LOCALLY DERIVED MOS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AS OF 400 AM EDT SUNDAY... A JET COUPLET PROVIDING DIFFLUENCE ALOFT WILL COMBINE WITH FRONTOGENESIS JUST ABOVE THE GROUND ACROSS SE WEST VA TO GENERATE LIGHT RAIN ON MONDAY MOSTLY BLUE RIDGE AND WEST. ALTHOUGH QPF WILL BE SMALL...POSSIBLY ONLY A FEW HUNDREDTHS...SPOTTY DRIZZLE WILL HELP TO MAKE THIS A DAMP AND COOL DAY. WITH PRECIP AND E TO NE FLOW CONTINUING...CAN`T SEE TEMPS GOING MUCH OF ANYWHERE...AND ALL OF THE GUIDANCE WITH THE EXCEPTION OF THE LOCALLY BIAS CORRECTED ECMWF LOOKS TOO WARM. QUITE POSSIBLE SOME OF THE COOLEST SPOTS DON`T EVEN REACH 45F WITH THE POSSIBILITY THAT MANY PLACES DON`T REACH 50F. CLOUDS BREAKING LATE MONDAY NIGHT SHOULD KEEP TUESDAY MORNING LOW TEMP A FEW WARMER THAN GUIDANCE...AND A RATHER WET AND WARM GROUND WITH TEMPS NOT FALLING INTO THE 30S UNTIL LATE SHOULD PRECLUDE ANY FROST. WITH ABUNDANT LLVL MOISTURE AND EASTERLY COMPONENT CONTINUING BLUE RIDGE AND EAST...HELD ONTO CLOUDS AND WENT WITH MAX T CLOSER TO THE 2M NAM VALUES TUESDAY. WEDGE FIGURES TO BE SLOWER TO LIFT OUT THAN OTHER MODELS DEPICT. THIS COULD BE ONE OF THOSE DAYS WHERE BCB IS WARMER THAN ROA AND LWB IS WARMER THAN DAN/LYH. CLOUDS SHOULD BREAK WEST OF THE BLUE RIDGE WITH MORE WESTERLY COMPONENT TUESDAY. SHOWERS SHOULD CRUMBLE ACROSS WEST VA WITH FRONT THAT APPROACHES ON WEDNESDAY WITH DEEP DOWNSLOPING FLOW AHEAD OF IT. BIG TEMP REBOUND THOUGH BLUE RIDGE AND EAST...EASILY THE BEST DAY OF THE NEXT SEVERAL WITH MAX T ONCE AGAIN IN THE 70S ON WEDNESDAY. A BETTER DRY PUNCH SETS THE STAGE FOR SOME NEAR FREEZING TEMPS PERHAPS THURSDAY MORNING ACROSS SE WEST VA...EXTREME SW VA AND NW NC. && .LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 400 PM EDT SATURDAY... ANOTHER FRONTAL BOUNDARY APPROACHES DURING THE WEEKEND AND ARRIVES EARLY NEXT WEEK...ALLOWING TEMPERATURES TO MODERATE. && .AVIATION /11Z SUNDAY THROUGH THURSDAY/... AS OF 715 AM EDT SUNDAY... WIDESPREAD SHOWERS EARLY THIS MORNING WITH AREAS OF MVFR CEILINGS WILL CONTINUE INTO THE EARLY AFTERNOON DUE AN APPROACHING UPPER LEVEL DISTURBANCE. ONCE THE UPPER LEVEL SYSTEM MOVES EAST AND WEAK LOW LEVEL NORTHWEST FLOW FORMS...CEILINGS TO RISE LATE THIS AFTERNOON AND THIS EVENING TO VFR CONDITIONS. THESE IMPROVING CONDITIONS WILL ONLY BE TEMPORARY AS ANOTHER UPPER LEVEL SYSTEM MOVING OVER THE REGION MONDAY WILL BRING WIDESPREAD MVFR/IFR CIGS AND LIGHT PRECIPITATION. HIGH PRESSURE BUILDING OVER THE AREA FOR TUESDAY WILL FINALLY BRING VFR CONDITIONS THAT ARE EXPECTED TO LAST THROUGH THURSDAY...ALTHOUGH A PERIOD OF MVFR CIGS POSSIBLE IN THE MTNS WITH A COLD FRONTAL PASSAGE WEDNESDAY. && .EQUIPMENT... THE KFCX DOPPLER RADAR...WHICH SERVES ROANOKE AND THE SURROUNDING AREAS...WILL REMAIN DOWN FOR THE NEXT FEW DAYS AS THE INSTALLATION OF THE NEW DUAL-POL TECHNOLOGY CONTINUES. THE RADAR MAY RETURN TO SERVICE AS EARLY AS THE MIDDLE OF NEXT WEEK. NEIGHBORING DOPPLER RADARS AT STERLING VA (KLWX)...WAKEFIELD VA (KAKQ)...RALEIGH NC (KRAX)...GREENVILLE-SPARTANBURG SC (KGSP)...MORRISTOWN TN (KMRX)...AND CHARLESTON WV (KRLX) WILL CONTINUE TO PROVIDE COVERAGE OVER PARTS OF THE KFCX AREA DURING THIS TIME FRAME. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...PH SHORT TERM...KM LONG TERM...KK AVIATION...PH EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
418 PM EDT SUN OCT 7 2012 .SYNOPSIS... AN AREA OF RAIN WILL MOVE OFFSHORE IN THE NEXT FEW HOURS FOLLOWED BY ANOTHER BAND OVERNIGHT. THE RAIN SHOULD COME TO AN END IN MOST LOCATIONS SHORTLY AFTER MIDNIGHT. OTHERWISE...THE MAIN STORY THIS WEEK WILL BE COOL FALL LIKE WEATHER WITH BELOW NORMAL TEMPERATURES. A FEW SHOWERS ARE POSSIBLE TUE/WED...BUT A WASHOUT IS NOT EXPECTED. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... LATEST REGIONAL RADAR MOSAIC SHOWING LIGHT RAIN MOVING ACROSS RI AND SOUTHEAST MA LATE THIS AFTERNOON. LOOKING FARTHER WEST AROUND 4 PM...WATCHING AN AREA OF LIGHT RAIN BLOSSOMING UNDER THE INFLUENCE OF A POTENT MID-LEVEL SHORTWAVE. BOTH THE 07/16Z HRRR AND THE 07/18Z RAP LOOK TO HAVE THE BEST HANDLE ON THE RAINFALL PATTERN...WHICH NOW LOOKS LIKE WILL COME IN TWO DISTINCT PERIODS. CURRENT FORECAST POPS FALL INTO THE HIGH POP/LOW RAINFALL AMOUNT CATEGORY. UPDATED THE RAINFALL TIMING BASED UPON THE 16Z HRRR AND 18Z RAP. CURRENT THINKING IS THE RAIN ACROSS SOUTHEAST MA AND RI WILL MOVE OFFSHORE EARLY THIS EVENING...RESULTING IN A MAINLY DRY PERIOD BEFORE A MID-LEVEL SHORTWAVE ARRIVES OVERNIGHT. ONCE THIS SHORTWAVE PASSES BY...EXPECTING A DRYING AND CLEARING TREND FROM WEST TO EAST LATE TONIGHT. TEMPERATURES WERE A BLEND OF THE MAV/MET MOS GUIDANCE. NOT SURE WE WILL HAVE ENOUGH TIME OF CLEAR SKIES TO GET MUCH FROST. DECIDED NOT TO ISSUE A FROST ADVISORY AT THIS TIME AS TEMPERATURES ARE NOT EXPECTED TO GET LOW ENOUGH. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... HIGH PRESSURE SHOULD MOVE ACROSS SOUTHERN NEW ENGLAND MONDAY...AND REACH A POSITION NEAR NOVA SCOTIA MONDAY NIGHT. LIGHT NORTHWEST WINDS BECOME LIGHT ONSHORE LATE MONDAY AFTERNOON INTO MONDAY NIGHT. WELL BELOW NORMAL TEMPERATURES EXPECTED MONDAY DESPITE PLENTY OF SUNSHINE TO START. INCREASING CLOUDS LATE IN THE DAY INTO MONDAY NIGHT. LEFT A CHANCE OF RAIN LATE MONDAY NIGHT AS ANOTHER LOW PRESSURE APPROACHES FROM THE SOUTH. THE CURRENT TIMING MAY BE A BIT ON THE FAST SIDE. TEMPERATURES WERE A BLEND OF THE MAV/MET MOS GUIDANCE ONCE AGAIN. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGHLIGHTS... * COOL FALL-LIKE WEATHER MOST OF THE WEEK * CONSIDERABLE CLOUDINESS TUE/WED WITH A FEW SHOWERS POSSIBLE * STRONG COLD FRONTAL PASSAGES WED NIGHT AND AGAIN FRI OVERVIEW AND MODEL PREFERENCES... 07/12Z MODEL GUIDANCE SUITE IN FAIRLY GOOD AGREEMENT THROUGH THE LONG TERM WITH THEIR HANDLING OF THE SYNOPTIC PATTERN. THE LARGE SCALE IS DEFINED BY A STRONG AND PERSISTENT HUDSON/S BAY VORTEX WITH WAVE ENERGY WRAPPING THROUGH THE BASE OF ITS LONGWAVE TROF. THE COMBINATION OF THIS TROF THE THE NW AND AN ATLANTIC RIDGE WILL YIELD A FAIRLY PERSISTENT WSW JET OVER THE AREA...LEADING TO AN UNSETTLED PERIOD THROUGH LATE WEEK...AFTER WHICH THE VORTEX WILL BEGIN TO LIFT N WITH TIME. GIVEN THAT THERE IS REASONABLY GOOD AGREEMENT BETWEEN THE MODELS...NOT PLANNING ON FAVORING ANY PARTICULAR MODEL FOR THE BASELINE OF THIS FORECAST. THEREFORE...WILL BEGIN WITH AN ECMWF/GFS BLEND AND MAKE MANUAL ADJUSTMENTS FOR BETTER HANDLING OF THE SENSIBLE WX DETAILS. DETAILS... TUE INTO WED... A RIDGE OF HIGH PRES WILL BE MOVING OVER THE AREA THROUGH THE PERIOD THANKS TO CONFLUENT FLOW ALOFT OVER MUCH OF SRN NEW ENGLAND. HOWEVER...A CONSTANT SHEAR VORTICITY MAXIMUM WILL ASSIST IN THE MOVEMENT OF A SFC LOW PRES IN PROXIMITY OF THE 40/70 BENCHMARK THROUGH THE PERIOD. THE BEST LLJ ENERGY...MOISTURE...AND F-GEN ARE WELL TO THE SW AND CLOSELY ASSOCIATED WITH THE LOW WITH DRY AIR AND SUBSIDENCE OVER MUCH OF SRN NEW ENGLAND FROM THE HIGH PRES. WITH MITIGATING FACTORS...IT APPEARS MODELS MAY BE A BIT TOO ROBUST WITH PRECIP OUTPUT THROUGH THE PERIOD...BUT A FEW SHOWERS CAN/T BE RULED GIVEN THE DIFFERENTIAL VORTICITY ADVECTION. WILL GENERALLY CAP POPS AT LOW CHANCE OVER SE PORTIONS OF THE FA...LOWER POPS TOWARD THE N AND W. MUCH OF THIS PERIOD WILL LIKELY BE DRY. TUE H85 TEMPS REMAIN AROUND +2C WHILE WED THEY INCREASE TO NEAR +8C...THEREFORE TEMPS WILL BE IN THE 50S TUE AND THE 60S WED. MINS WILL LIKELY BE IN THE 40S. WED EVENING INTO THU... A STRONG KICKER TROF WILL BE ROTATING THROUGH SRN ONTARIO AND THE GREAT LAKES. THE SFC REFLECTION IS A STRONG COLD FRONT WHICH WILL CROSS THE REGION DURING THE OVERNIGHT WED NIGHT. SOUNDINGS SHOW DECENT MOISTURE LOADING AND THERE ARE FAIRLY GOOD DYNAMICS WITH THIS SYSTEM...SO WIDESPREAD WET WX IS LIKELY WITH THIS COLD FROPA. THE FRONT IS CLOSELY ASSOCIATED WITH A 30-40KT LLJ AND H85 TEMPS COOLING TO NEARLY 0C...SO THERE IS SOME LOW LVL INSTABILITY POSSIBLE. GIVEN THESE FACTORS CANNOT RULE OUT THE POSSIBILITY OF BRIEFLY HEAVY RAIN AND A/OR A LOW TOPPED SQUALL LINE ASSOCIATED WITH THE FRONT ITSELF. THERE IS THE POSSIBILITY IT WILL SLOW SOMEWHAT AS IT REACHES THE E COAST AS IT GETS WRAPPED UP WITH THE WEAK LOW PRES OFFSHORE. IN ANY CASE...WET UNSETTLED WX WILL BE LIKELY WED EVENING INTO THU MORNING...WITH COOL NW FLOW LIKELY DURING THE DAY THU BEHIND THE FRONT. FRI AND SAT... WITH THE KICKER TROF FROM THU HAVING SHIFTED THE PERSISTENT HUDSON BAY VORTEX FURTHER N AND E...A SE CONUS RIDGE WILL BE ALLOWED TO SHIFT N WITH ITS ASSOCIATED STRONG HIGH PRES FRI INTO SAT. THEREFORE DRY COOL WX WILL PREVAIL. MODELS SUGGEST A WEAK CLIPPER SYSTEM MAY PASS TO THE N EARLY FRI...BUT GIVEN ITS CP ORIGINS AND PASSAGE WELL TO THE N THIS MAY PASS THE REGION DRY WITH THE RIDGE CONTINUALLY BUILDING AS IT PASSES. SUN INTO EARLY NEXT WEEK... AVAILABLE GUIDANCE SHOWS A VERY STRONG LOW PRES MOVING THROUGH THE AREA BEGINNING SUN AFTERNOON WITH MORE WET WX POSSIBLE. BOTH OPNL RUNS OF THE GFS AND ECMWF AS WELL AS MANY OF THEIR COMPLIMENTARY ENSEMBLE MEMBERS ARE SHOWING THIS...SO CONFIDENCE INA TRANSITION TOWARD WET WX LATE IN THE WEEKEND AND EARLY NEXT WEEK IS A HIGHER THAN USUAL CONFIDENCE FORECAST FOR 7 DAYS OUT. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT OVERVIEW...HIGH CONFIDENCE. EXPECTING PRIMARILY VFR CIGS TONIGHT. AREAS OF MVFR VSBYS IN HEAVIER RAINFALL. SHOULD LEAD TO DAMP RUNWAYS AT LEAST. MODERATE CONFIDENCE IN MVFR CIGS ACROSS PORTIONS OF SOUTHEAST MA AND THE COASTAL WATERS BETWEEN 03Z-09Z. LOW CONFIDENCE IN IFR CONDITIONS OVERNIGHT. CLEARING FROM WEST TO EAST AFTER 09/06Z WITH VFR TO PREVAIL MONDAY INTO MONDAY NIGHT. KBOS TAF...HIGH CONFIDENCE IN TAF. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...TUESDAY THROUGH FRIDAY... TUESDAY AND WEDNESDAY...LOW TO MODERATE CONFIDENCE. COMPLEX MIX OF VFR TO MVFR AND IFR WITH LOW PRESSURE MOVING SE OF THE AREA. BEST CHANCE FOR LOWER CATEGORIES WILL BE IN SHOWERS PARTICULARLY SE MA/RI TERMINALS. THURSDAY AND FRIDAY...HIGH CONFIDENCE IN VFR CONDITIONS. && .MARINE... ISSUED A SMALL CRAFT ADVISORY ACROSS THE OUTER COASTAL WATERS SOUTH AND EAST OF NANTUCKET DUE TO GUSTY WINDS AND BUILDING SEAS. ELSEWHERE...EXPECTING RELATIVELY TRANQUIL CONDITIONS OTHER THAN THE RAINFALL AND OCCASIONALLY LOWER VISIBILITY. COULD SEE ANOTHER EPISODE FOR MARGINAL SMALL CRAFT ADVISORY CONDITIONS LATE MONDAY NIGHT. OUTLOOK...TUESDAY THROUGH FRIDAY... TUE...MODERATE CONFIDENCE. SCA LIKELY NEEDED FOR INCREASING WINDS 25-30 KT AND HIGH SEAS WITH LOW PRESSURE OFF THE SE COAST. VSBYS LOWER IN SHOWERS. WED INTO THU... SMALL CRAFT CONDITIONS LOWER TUE NIGHT INTO WED WITH A PERIOD OF QUIET BOATING WEATHER EXPECTED. HOWEVER A STRONG COLD FRONT WILL APPROACH LATE IN THE DAY WED...CROSSING THE WATERS EARLY THU MORNING. WINDS WILL INCREASE 25-30 KT BOTH BEFORE AND AFTER THE COLD FRONTAL PASSAGE. SMALL CRAFT ADVISORIES MAY BE NEEDED...AND THERE IS THE SLIGHT CHANCE FOR SOME GALE FORCE GUSTS PARTICULARLY RIGHT AROUND THE TIME OF THE FRONTAL PASSAGE. MODERATE CONFIDENCE. FRI... MODERATE CONFIDENCE THAT SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE INTO THE DAY FRIDAY. EVEN THOUGH WINDS MAY SUBSIDE SOMEWHAT THU NIGHT...THEY WILL PICK UP AGAIN TO 25 KT FRI. SEAS...PARTICULARLY ON THE OUTER WATERS MAY EXCEED 5 FT DURING THE PERIOD. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 4 AM EDT MONDAY FOR ANZ254-255. && $$ SYNOPSIS...BELK/DOODY NEAR TERM...BELK SHORT TERM...BELK LONG TERM...DOODY AVIATION...BELK/DOODY MARINE...BELK/DOODY
AREA FORECAST DISCUSSION
NWS MIAMI FL
127 PM EDT SUN OCT 7 2012 .AVIATION... DEEP MOISTURE...LIGHT WINDS...AND UNSTABLE CONDITIONS ACROSS THE REGION WILL LEAD TO SCATTERED THUNDERSTORMS DEVELOPING AREAWIDE. STORMS WILL BE SLOW MOVING. MVFR CONDITIONS WILL BE POSSIBLE IN AND AROUND THUNDERSTORMS. A GULF COAST SEA BREEZE IS EXPECTED TO DEVELOP BY 19Z AT KAPF...WITH A NW FLOW. LIGHT WINDS ARE EXPECTED OVERNIGHT...AND SHOWERS MAY BE POSSIBLE NEAR THE EAST COAST TAF SITES AROUND DAYBREAK. && .PREV DISCUSSION... /ISSUED 921 AM EDT SUN OCT 7 2012/ UPDATE... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE ATLANTIC WATERS MAKING THEIR WAY ONSHORE THE SOUTHEAST FLORIDA COAST THIS MORNING. WATERSPOUTS ARE POSSIBLE WITH SOME OF THESE SHOWERS...SIMILAR TO YESTERDAY...AND WILL CONTINUE TO MENTION THIS IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. MORNING SOUNDING FROM MIAMI SHOWS LITTLE CHANGE FROM YESTERDAY WITH LOTS OF MOISTURE. THE SOUNDING FROM KEY WEST, HOWEVER, SHOWS A SUBTLE DRIER LAYER FROM 850 MB TO 700 MB. SHORT RANGE MODELS INCLUDING THE HRRR AREN`T SHOWING AS MUCH CONVECTION OVER THE SOUTHERN PENINSULA THIS AFTERNOON COMPARED TO PAST COUPLE OF DAYS. GLOBAL MODELS (GFS AND ECMWF) SHOW A WEAK MID-LEVEL SHORTWAVE PASSING THROUGH SOUTH FLORIDA THIS MORNING (POTENTIALLY CONTRIBUTING TO INCREASED ATLANTIC AND COASTAL CONVECTION THIS MORNING) AND OVER THE ATLANTIC THIS AFTERNOON. THE DRIER AIR OBSERVED AT KEY WEST MAY BE AN INDICATION OF SUBSIDENCE BEHIND THE SHORTWAVE AND MODELS COULD BE PICKING UP ON THIS. HAVING SAID ALL THIS, STILL EXPECT AT LEAST SCATTERED SHOWERS/TSTMS OVER INTERIOR AREAS THIS AFTERNOON WITH SLOW MOVEMENT OF CELLS LEADING TO LOCALLY HIGH RAINFALL AMOUNTS. HOWEVER, WOULD NOT BE SURPRISED TO SEE LESS ACTIVITY THIS AFTERNOON AS PER MODEL TRENDS INDICATED ABOVE. MOLLEDA PREV DISCUSSION... /ISSUED 727 AM EDT SUN OCT 7 2012/ AVIATION... CIRRUS CLOUDS COVER MUCH OF THE REGION THIS MORNING...FROM CONVECTION LAST NIGHT. LIGHT WINDS THIS MORNING WILL BECOME EASTERLY WITH DIURNAL HEATING LATER TODAY. A WEST COAST SEA BREEZE IS ALSO EXPECTED TO BECOME ESTABLISHED BY EARLY AFTERNOON. THIS WILL SET THE STAGE AGAIN FOR SCT TSRAS ACROSS MUCH OF THE SOUTH FLORIDA AREA...ESPECIALLY ACROSS INTERIOR AREAS. ACTIVITY SHOULD DIMINISH SHORTLY AFTER NIGHTFALL. PREV DISCUSSION... /ISSUED 255 AM EDT SUN OCT 7 2012/ SHORT TERM (TODAY-TUESDAY)... THE LATEST SURFACE ANALYSIS EARLIER THIS MORNING SHOWED A COLD FRONT EXTENDING SOUTHWEST FROM THE CAROLINAS TO THE CENTRAL GULF COAST STATES AND WEAK HIGH PRESSURE CENTERED NORTHEAST OF THE LOCAL AREA OFF THE NERN FLORIDA COAST ACROSS THE WESTERN ATLANTIC. MOIST EASTERLY LOW-LEVEL FLOW SOUTH OF THIS HIGH WILL PERSIST OVER THE AREA INTO MONDAY AS THE COLD FRONT GRADUALLY CONTINUES SOUTHEASTWARD INTO THE STATE AND HIGH PRESSURE BUILDS ACROSS THE REGION IN ITS WAKE. RECENTLY ANIMATED WATER VAPOR LOOP SHOWED BROAD CYCLONIC FLOW ACROSS THE MID-SECTION AND EASTERN HALF OF THE COUNTRY CHARACTERIZED WITH A FAIRLY STRONG SHORTWAVE TROUGH DIGGING SOUTHEAST AND EAST ACROSS THE PLAINS. MID TO UPPER SW FLOW ALONG WITH PLENTY OF MID/UPPER MOISTURE AHEAD OF THIS UPPER TROUGH CONTINUES TO STREAM OVERHEAD. MODEL SOUNDING PROFILES REMAIN FAIRLY WET ACROSS THE LOCAL AREA THROUGH THE BULK OF THIS SHORT-TERM PERIOD WITH PW`S REMAINING AROUND THE 2" INCH MARK. ONE MAIN DIFFERENCE OR TREND NOTED FROM RUN TO RUN WITHIN THE MODELS HAS BEEN THE DECREASE IN SOUTHWARD PROGRESSION OF THE FRONTAL BOUNDARY INTO OUR LOCAL AREA OVER THE NEXT COUPLE OF DAYS. THE LATEST MODEL CYCLE INDICATES THE BOUNDARY STALLING OVER CENTRAL FLORIDA SOMETIME BETWEEN MONDAY EVENING AND TUESDAY...WHEREAS BEFORE...ALL INDICATIONS INDICATED THE BOUNDARY PROGRESSING INTO THE AREA WITH DRIER AIR FILTERING IN BEHIND IT. THIS WILL RESULT IN THE RAIN CHANCES REMAINING IN THE FORECAST THROUGH THIS PERIOD WITH THE BEST POTENTIAL FOR THE DRIER AIR LATER THROUGH THE MID/LATTER HALF OF THE WEEK. THE LATEST WRF MODEL REFLECTIVITIES SUPPORT THIS AND GENERALLY INDICATE THE BULK OF THE ACTIVITY SETTING UP OVER THE INTERIOR AND GULF COAST REGIONS THROUGH THE AFTERNOON AND EVENING PERIODS. HOWEVER...SIMILAR TO YESTERDAY...SCATTERED SHOWERS AND STORMS DEVELOPING AND SPREADING WEST ACROSS THE EASTERN HALF OF THE AREA WILL REMAIN POSSIBLE THROUGH THE FIRST HALF OF THE DAY TODAY. THE LATEST MODEL GUIDANCE INDICATES AN ADDITIONAL HALF OF AN INCH TO AN INCH ACROSS THE WESTERN HALF OF THE AREA OVER THE UPCOMING FEW DAYS...WHICH LINES UP WELL WITH THE LATEST HPC GUIDANCE. LOCALLY HIGHER AMOUNTS WILL REMAIN POSSIBLE WHERE THE ACTIVITY BECOMES CONCENTRATED THROUGH THIS TIME. AS A RESULT...THE MAIN CONCERNS WILL BE THE POTENTIAL FOR LOCALIZED FLOODING AND WET MICROBURSTS/GUSTY WINDS IN AND AROUND THE HEAVIER ACTIVITY OR STRONG STORMS THAT DEVELOP. LONG TERM...(TUESDAY NIGHT-SATURDAY) THE LATEST GFS/GFS ENSEMBLE AND ECMWF REMAIN IN DECENT AGREEMENT ON THE LARGE SCALE THROUGH THE MID-WEEK PERIOD AND GENERALLY KEEP THE BROAD CYCLONE FLOW IN PLACE ACROSS THE EASTERN STATES. HOWEVER...ALL CONTINUE TO SUGGEST MUCH DRIER DEEP LAYER AIR SPREADING SOUTH AS THE PREVIOUSLY DISCUSSED FRONTAL BOUNDARY STALLS AND DIMINISHES AND THE MEAN UPPER TROUGH AXIS SHIFTS EWD. THIS DRY AIR WILL TRANSLATE TO A SLIGHT DECREASE IN DEWPOINTS...POSSIBLY INTO THE UPPER 60S INLAND AND NORTH AROUND THE LAKE REGION. WILL REFLECT THIS WITH DECREASING RAINFALL CHANCES THROUGH THIS TIME ACROSS THE AREA. NO NOTABLE CHANGES REGARDING THE DAILY HIGH AND LOW TEMPERATURES THROUGH THIS EXTENDED PERIOD. MARINE... LIGHT EASTERLY FLOW WILL PERSIST INTO THE UPCOMING WEEK AS A WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND NORTHWEST. SCATTERED SHOWERS AND STORMS WILL REMAIN IN THE FORECAST THROUGH THIS TIME. DRIER AIR WITH LIGHT TO MODERATE NORTHEAST WINDS WILL BECOME A POSSIBILITY THROUGH THE MIDDLE PART OF THE UPCOMING WEEK. SEAS WILL RESPOND AND INCREASE INTO THE 3 TO 5 FOOT RANGE ACROSS THE ATLANTIC WATERS. FIRE WEATHER... DESPITE THE DRIER AIR PROGGED TO FILTER INTO THE AREA FROM NORTH TO SOUTH NEXT WEEK...RELATIVE HUMIDITIES ARE FORECAST TO REMAIN WELL ABOVE CRITICAL LEVELS WITH NO RED FLAG CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 88 78 89 / 30 40 30 30 FORT LAUDERDALE 79 88 77 88 / 30 40 30 30 MIAMI 78 89 77 89 / 30 40 30 30 NAPLES 75 90 75 89 / 30 40 30 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...59/RM AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
300 PM CDT SUN OCT 7 2012 .DISCUSSION... ISSUED 300 PM CDT SUN OCT 7 2012 A CHILLY DAY CONTINUES TO UNFOLD ACROSS CENTRAL AND SOUTHEAST ILLINOIS THIS AFTERNOON...SOON TO BE FOLLOWED BY ONE MORE CHILLY NIGHT...AS COOL HIGH PRESSURE SETTLES SOUTHEAST ACROSS THE REGION. ASIDE FROM HOW COLD IT WILL GET TONIGHT...ALONG WITH ANY FROST/FREEZE POTENTIAL...PRIMARY FORECAST CONCERN TODAY REVOLVES AROUND PRECIPITATION CHANCES TUESDAY NIGHT AND THURSDAY NIGHT WITH TWO COLD FRONTAL PASSAGES...AS WELL AS HEADING INTO THE WEEKEND WITH A MORE VIGOROUS WEATHER SYSTEM. 12Z MODELS REMAIN IN SURPRISINGLY GOOD AGREEMENT FOR MUCH OF THE WEEK. THEIR AGREEMENT AND RUN-TO-RUN CONSISTENCY HAS BEEN GOOD FOR MOST OF THE FORECAST PERIOD. HOWEVER...THERE REMAINS SOME TIMING/STRENGTH DIFFERENCES AND FLIP-FLOPPING WITH THE ARRIVAL UPPER LOW REMNANTS FROM THE REX BLOCK OFF THE PACIFIC COAST. A ENSEMBLE MEAN SOLUTION SHOULD CONTINUE TO BE THE BEST OPTION FOR NOW. SHORT TERM...TONIGHT THROUGH WEDNESDAY...FOR THE FIRST TIME IN A COUPLE NIGHTS...UNCERTAINTIES WITH CLOUD COVER WILL NOT COMPLICATE THE OVERNIGHT LOW TEMPERATURE FORECAST. HOWEVER...THE SURFACE RIDGE AXIS WILL BE SLIDING SOUTHEAST ACROSS THE AREA TONIGHT...WITH WINDS TURNING SOUTHERLY IN ITS WAKE. THIS SCENARIO SHOULD PRECLUDE WIDESPREAD FROST/FREEZING CONDITIONS IN THE WESTERN PORTION OF THE FORECAST AREA. IT WILL BE A CLOSER CALL IN THE EAST WHERE WINDS WILL BE SLOWER TO TURN SOUTHERLY. SO...HAVE OPTED TO GO WITH A FROST ADVISORY IN THIS AREA...ALTHOUGH BRIEF/LOCAL FREEZING CONDITIONS CAN NOT BE RULED OUT. DEEP SOUTHERLY FLOW WILL GRADUALLY DEVELOP MONDAY INTO TUESDAY AS THE SURFACE HIGH DRIFTS FURTHER TO THE EAST AND AN UPPER WAVE DIGGING INTO THE PLAINS HELPS INITIATE DOWNSTREAM RIDGING. THIS SCENARIO IS SUPPORTIVE OF SLOWLY MODERATING TEMPERATURES...WITH TEMPERATURES AT OR ABOVE NORMAL BY TUESDAY. THE PATTERN IS ALSO CONDUCIVE TO DEEP DIURNAL MIXING AND GUSTY WINDS SHOULD DEVELOP DAILY MONDAY AND TUESDAY. THE DIGGING WAVE WILL PUSH A FRONTAL BOUNDARY THROUGH THE AREA TUESDAY NIGHT...ACCOMPANIED BY PRIMARILY POST FRONTAL SHOWERS. THERE IS GOOD ISENTROPIC ASCENT AHEAD OF THE FRONT...BUT CONDENSATION PRESSURE DEFICITS SUGGEST THE PRE-FRONTAL AIRMASS WILL BE FAR TOO DRY TO SUPPORT PRECIPITATION. THERE IS DECENT COUPLED JET FORCING AND MID-LEVEL FRONTOGENESIS BEHIND THE FRONT AS THE UPPER WAVE MOVES THROUGH...BUT EXPECTED MOISTURE AVAILABILITY PRECLUDES ME FROM GOING ABOVE CHANCE POPS AT THIS TIME. ANOTHER BRIEF SHOT OF QUIET/COOLER WEATHER IS ANTICIPATED BEHIND THE FRONT FOR WEDNESDAY. LONG TERM...THURSDAY THROUGH SUNDAY...SOUTHERLY LOW LEVEL FLOW AND RISING HEIGHTS SIGNAL A RETURN TO MORE SEASONABLE TEMPERATURES FOR THURSDAY...BEFORE A MOSTLY DRY FRONTAL PASSAGE COOLS THINGS DOWN A BIT FOR FRIDAY. THEN...ATTENTION TURNS TO THE REMNANTS OF THE UPPER LOW OFF THE PACIFIC COAST. CONFIDENCE IS GROWING THAT THIS SYSTEM WILL USHER IN A PERIOD OF WARMER WEATHER...ALONG WITH SHOWERS/STORMS...AS IT MOVES THROUGH. AS MENTIONED ABOVE...DUE TO THE REMAINING UNCERTAINTIES REVOLVING AROUND THIS SYSTEM/S ULTIMATE ARRIVAL...HAVE KEPT POPS IN THE CHANCE CATEGORY. BAK && .AVIATION... ISSUED 1208 PM CDT SUN OCT 7 2012 RAPID DIURNAL CLOUD DEVELOPMENT AT 5000 FEET OCCURRED AROUND 15Z...WITH BROKEN CEILINGS NOW WIDESPREAD OVER THE TAF SITES. ALREADY STARTING TO SEE SOME THINNING OF THE CLOUDS WEST OF KPIA/KSPI...AND CU-RULE OFF THE RAP MODEL SHOWS CONTINUED DIMINISHING OF THE CLOUDS FROM WEST TO EAST. BY 00Z...THE REMAINING CLOUDS SHOULD LARGELY BE SOUTHEAST OF THE TAF SITES. OVERNIGHT...WEST WINDS WILL GRADUALLY TREND TOWARD THE SOUTHWEST AND SOUTH AS HIGH PRESSURE PASSES TO OUR SOUTH. WHILE SKIES REMAIN CLEAR INTO MONDAY...A TIGHTENING PRESSURE GRADIENT WILL LEAD TO SOME GUSTY SOUTHWEST WINDS BY LATE MORNING...WITH SOME GUSTS ABOVE 15 KNOTS AT MOST SITES. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 1 AM TO 8 AM CDT MONDAY FOR ILZ038-042>046- 051>057-061>063-066>068-071>073. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1209 PM CDT SUN OCT 7 2012 .DISCUSSION... ISSUED 1003 AM CDT SUN OCT 7 2012 HIGH PRESSURE WAS CENTERED OVER EASTERN KANSAS LATE THIS MORNING...RIDGING NORTHEAST INTO WISCONSIN. RAPID CLEARING HAS BEEN TAKING PLACE OVER MOST OF THE CWA THE LAST COUPLE HOURS... WITH AREAS FROM ABOUT I-74 NORTHWARD STILL MOSTLY CLOUDY BUT RAPIDLY CLEARING. SUBSIDENCE FROM THE HIGH SHOULD KEEP SKIES MOSTLY SUNNY THROUGH THE AFTERNOON...WITH CU-RULE OFF THE NAM AND RAP MODELS STILL SHOWING SOME DIURNAL DEVELOPMENT ACROSS THE EASTERN CWA FOR A COUPLE HOURS AROUND MIDDAY. HAVE SENT SOME UPDATED ZONES/GRIDS TO REFLECT THE SKY TRENDS. TEMPERATURES LOOKED FAIRLY GOOD AND NO CHANGES MADE TO THE HIGHS. GEELHART && .AVIATION... ISSUED 1208 PM CDT SUN OCT 7 2012 RAPID DIURNAL CLOUD DEVELOPMENT AT 5000 FEET OCCURRED AROUND 15Z...WITH BROKEN CEILINGS NOW WIDESPREAD OVER THE TAF SITES. ALREADY STARTING TO SEE SOME THINNING OF THE CLOUDS WEST OF KPIA/KSPI...AND CU-RULE OFF THE RAP MODEL SHOWS CONTINUED DIMINISHING OF THE CLOUDS FROM WEST TO EAST. BY 00Z...THE REMAINING CLOUDS SHOULD LARGELY BE SOUTHEAST OF THE TAF SITES. OVERNIGHT...WEST WINDS WILL GRADUALLY TREND TOWARD THE SOUTHWEST AND SOUTH AS HIGH PRESSURE PASSES TO OUR SOUTH. WHILE SKIES REMAIN CLEAR INTO MONDAY...A TIGHTENING PRESSURE GRADIENT WILL LEAD TO SOME GUSTY SOUTHWEST WINDS BY LATE MORNING...WITH SOME GUSTS ABOVE 15 KNOTS AT MOST SITES. GEELHART && .PREV DISCUSSION... ISSUED 326 AM CDT SUN OCT 7 2012 THE COLDEST AIR WE WILL SEE WITH THIS AIRMASS WILL MAKE ITS FARTHEST SOUTHWARD PROGRESSION INTO CENTRAL ILLINOIS THIS MORNING BETWEEN 12Z AND 18Z...THEN MID LEVEL WARMING WILL DEVELOP AND CONTINUE UNTIL THE NEXT COLD FRONT ARRIVES TUESDAY NIGHT. WE WILL HAVE MUCH CLEARER SKIES SUNDAY NIGHT...SO EVEN THOUGH THE COLDEST AIR WILL HAVE MOVED EAST OF ILLINOIS...FROST/FREEZE POTENTIAL WILL RETURN FOR AREAS MAINLY EAST OF I-57. THE NEXT RAIN CHANCES WILL COME WITH COLD FRONTAL PASSAGES ON TUESDAY NIGHT AND THURSDAY NIGHT...THEN AGAIN WITH A MORE LARGE SCALE LOW PROJECTED TO ARRIVE EARLY NEXT WEEKEND. THE OVERALL MODEL GUIDANCE REMAINS IN RELATIVE AGREEMENT ON TIMING THE MAJOR WEATHER FEATURES...AND A GENERAL BLEND WILL BE CONTINUED. THERE REMAINS SOME UNCERTAINTY AS TO HOW FAST THE CUTOFF LOW ON THE WEST COAST WILL EJECT ACROSS THE COUNTRY MID WEEK AND ARRIVE NEXT WEEKEND. SO WE TEMPERED DOWN THE LIKELY POP FROM THE ALL-BLEND FOR LATE IN THE EXTENDED. SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT. LOW CLOUDS HAVE HUNG TOUGH ACROSS THE AREA TONIGHT...KEEPING LOW TEMPS FROM BOTTOMING OUT AROUND FREEZING IN THE NW. TEMPS IN THAT AREA ARE STILL DOMINATED BY UPPER 30S AND LOWER 40S AT 08Z...BUT SOME THINNING TO THE LOW CLOUD DECK MAY OCCUR IN THE FAR WEST BY SUNRISE. THE LATEST RAP(RUC) GUIDANCE HAS A DECENT HANDLE ON THE CURRENT CLOUD TRENDS...AND INDICATES A GRADUAL DEPARTURE OF CLOUDS TODAY. THE NW AREAS SHOULD SEE SOME CLEARING BY NOON...WITH CLOUDS DISSIPATING IN THE EAST DUE TO MIXING OF DRY AIR FROM ALOFT AS CLOUDS CONTINUE TO DEPART EASTWARD. THE INCREASING SUNSHINE WILL STILL HAVE A TOUGH TIME BATTLING THE COLD POOL AND 850MB TEMPS AROUND -3C TO -4C. HIGHS WILL STRUGGLE TO REACH INTO THE LOWER 50S. CLEAR SKIES AND LIGHT WINDS WILL BE ESPECIALLY PROMINENT FOR AREAS EAST OF I-57...CLOSER TO THE DEPARTING COLD POOL. THEREFORE...THE BETTER CHANCES FOR ANY FROST OR FREEZING CONDITIONS WILL OCCUR THERE. WE CANT RULE OUT SOME FROST CONDITIONS FOR OUR FAR NORTHERN COUNTIES /KNOX-STARK-MARSHALL/ BUT FROST CHANCES WILL BE LOWER IN THE WESTERN AREAS DUE TO A SOUTHERLY WIND THAT WILL BEGIN TO DEVELOP BY 12Z/7AM MONDAY. THAT SOUTHERLY RETURN FLOW WILL TRIGGER A WARMING TREND AT THE SURFACE AND ALOFT UNTIL THE ARRIVAL OF OUR NEXT COLD FRONT TUESDAY NIGHT. HIGHS ON MONDAY WILL CLIMB INTO THE LOW 60S IN THE WEST...WITH AROUND 60 IN THE EAST. TUESDAY WILL SEE INCREASING HIGH CLOUDS LATE IN THE DAY...BUT ENOUGH SUNSHINE SHOULD BE PRESENT ALONG WITH GUSTY SOUTH WINDS TO BUMP HIGHS INTO THE MID 60S NORTHEAST TO LOW 70S SOUTHWEST. DESPITE AN ACTIVE FRONTAL CIRCULATION AND ISENTROPIC UPGLIDE WITH THE FRONTAL PASSAGE TUESDAY NIGHT...MOISTURE LEVELS WILL NOT BE EXCESSIVELY HIGH. THAT IS NOTED BY THE NAM PRESENTING A DRY FRONTAL PASSAGE. HOWEVER...THE GFS/GEM/ECMWF ALL HAVE BEEN CONSISTENT WITH GENERATING SHOWER ACTIVITY IN A MAJORITY OF CENTRAL IL AT SOME POINT TUES NIGHT. THEREFORE...WE KEPT MID CHANCE POPS GOING. SHOWERS WILL BE ENDING FROM WEST TO EAST AFTER MIDNIGHT...WITH EVEN SOME CLEARING WEST OF I-55 BY 12Z/7AM WED. LONG TERM...WEDNESDAY THROUGH SATURDAY. A COOLER NORTHWEST FLOW BEHIND THAT COLD FRONT WILL KEEP WEDNESDAYS HIGHS IN THE UPPER 50S TO AROUND 60. A QUICK REBOUND IN TEMPS IS EXPECTED FOR THURSDAY AHEAD OF THE NEXT COLD FRONT. BREEZY SOUTH WINDS AND MID LEVEL WARM AIR ADVECTION WILL HELP BOOST THURSDAYS HIGHS BACK INTO THE MID 60S. THURSDAY NIGHT CONTINUES TO BE THE TARGET PERIOD FOR RAIN CHANCES WITH THE SECOND COLD FRONT THIS WEEK. GULF MOISTURE RETURNING UP THE MISSISSIPPI RIVER VALLEY WILL FUEL A BAND OF SHOWERS AHEAD OF THE FRONT. HOWEVER...THE TRACK OF AN UPPER LEVEL SHORTWAVE FROM WEST TO EAST ACROSS SOUTHERN IL AS THE FRONT ARRIVES MAY KEEP THE BULK OF THE RAINFALL JUST TO THE SOUTH OF OUR COUNTIES. WE TRENDED CHANCES POPS FARTHER SOUTH...MAINLY SOUTH OF I-70...WITH SLIGHT CHANCE POPS UP TO I-72. FRIDAY SHOULD REMAIN DRY WITH A 1030MB HIGH PASSING ACROSS THE UPPER MIDWEST. THE ECMWF AND GFS...AS WELL AS THE LAST 24HRS OF THE 00Z CANADIAN GEM SHOW THE REX BLOCK/CUT-OFF LOW ALONG THE WEST COAST EJECTING RAPIDLY ACROSS THE COUNTRY STARTING LATE THURSDAY NIGHT. THE SPEED WITH WHICH THIS FEATURE MOVES ACROSS THE ROCKIES MAY BE A BIT OVERDONE...SO THE ARRIVAL TIME OF RAIN NEXT WEEKEND MAY BE DELAYED FROM CURRENT MODEL INDICATIONS. WE KEPT CHANCE POPS GOING IN THE WEST ON FRIDAY NIGHT AND EVERYWHERE ON SATURDAY...BUT TEMPERED BACK FROM THE MORE AGGRESSIVE NUMBERS OF THE ALL-BLEND. SHIMON && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
144 PM EDT SUN OCT 7 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 503 AM EDT SUN OCT 7 2012 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW FULL LATITUDE UPR TROF OVER ERN NAMERICA...WITH NW FLOW ALF OVER THE UPR GRT LKS. WITH H85 TEMPS ARND -7C OVER LK SUP /VS WATER TEMPS RANGING FM 6-7C OVER THE W TO 11-12C OVER THE E/...A WEAK SHRTWV MOVING THRU THE UPR LKS...AND ADEQUATE LLVL MSTR PER THE 00Z APX RAOB...SOME LK EFFECT -SHRA MIXED WITH SN CONTINUE OVER MAINLY THE E HALF OF THE LK WHERE INSTABILITY REMAINS GREATEST. PERSISTENT CNVGC SHOWN BY WIND OBS OVER THE E HALF OF THE LAKE ARE ALSO HELPING TO MAINTAIN THE COVERAGE/INTENSITY OF THIS PCPN IN THAT AREA. OVER THE W...MORE ACYC LLVL FLOW ASSOCIATED WITH SFC RDG EXTENDING FM HI CENTER IN THE SCNTRL PLAINS TOWARD THE UPR MIDWEST...COOLER WATERS...AS WELL AS SOMEWHAT DRIER LLVL AIR SHOWN ON THE 00Z INL RAOB ARE CONSPIRING TO LIMIT THE ACTIVITY OVER THAT PART OF THE LAKE. ALTHOUGH DRIER AIR OVER THE NRN PLAINS PER THE 00Z BISMARCK RAOB IS SHIFTING TO THE E IN THE WLY FLOW ON THE NRN FLANK OF THE HI CENTER IN THE SCNTRL PLAINS...THERE IS A GOOD DEAL OF MID/HI CLD EXTENDING FM ARND LK WINNIPEG INTO THE NRN PLAINS ASSOCIATED WITH ISENTROPIC ASCENT ON THE 290-295K SFCS /H7-575/. TODAY...SHORT TERM MODELS ARE IN GOOD AGREEMENT SHOWING LARGER SCALE FLOW OVER THE ENTIRE CWA SHIFTING TO THE W AS HI PRES OVER THE SCNTRL PLAINS SHIFTS TOWARD THE OH RIVER VALLEY...WHICH SHOULD WEAKEN THE LLVL CNVGC NOW PRESENT OVER THE E HALF AND ADVECT WARMER H85 TEMPS/DRIER LLVL AIR TO THE W OVER THE CWA. THESE TRENDS WL TEND TO STEADILY WEAKEN THE ONGOING LK EFFECT PCPN NOW IMPACTING MAINLY THE E HALF OF THE CWA. THE ARRIVAL OF THE DRIER AIR WL ALSO RESULT IN MORE SUNSHINE...WHICH WL BE DIMMED AT TIMES BY THE BKN HIER CLDS DRIFTING INTO THE AREA FM THE NW. MIXING TO H8 ON NAM/GFS FCST SDNGS YIELDS HI TEMPS MAINLY 45-50...EXCEPT IN THE LO 50S WHERE THE INCRSG W WIND DOWNSLOPES OVER THE CENTRAL. SUN NGT...AS NEXT SHRTWV/SFC LO DIGS SEWD THRU SCNTRL CANADA TO NEAR LK WINNIPEG AND SFC HI PRES SHIFTS INTO THE OH RIVER VALLEY BY 12Z...A STRENGTHENING WSW FLOW WL DVLP OVER THE UPR LKS WITH H925 WINDS INCRSG UP TO 25-35 KTS BY 12Z MON. ALTHOUGH SOME MID/HI CLDS ASSOCIATED WITH THE ISENTROPIC ASCENT ON THE 290K SFC WL BE OVER THE UPR LKS...THESE CLDS WL BE RATHER THIN. PWATS AS LO AS 0.25-0.30 INCH INDICATE TEMPS WL STILL FALL FAIRLY SHARPLY OVER THOSE INTERIOR LOCATIONS ESPECIALLY OVER THE SCNTRL THAT CAN DECOUPLE BEFORE THE H925 FLOW STRENGTHENS TOO MUCH OVERNGT. LOCATIONS NEAR LK SUP SHOULD BE WARMEST WITH DOWNSLOPE FLOW. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 503 AM EDT SUN OCT 7 2012 BY MONDAY MORNING THE UPPER GREAT LAKES WILL BE COMPLETELY WITHIN A LARGE 500MB TROUGH THAT WILL ENCOMPASS ALL BUT THE FAR SW CORNER OF THE NATION...EXTENDING FROM THE MAIN LOW OVER N CANADA THROUGH HUDSON BAY. FCST MODELS AGREE WITH THE ENHANCEMENT IN THE MAIN THROUGH SET UP FROM S HUDSON BAY THROUGH CENTRAL SASKATCHEWAN BY MONDAY AFTERNOON...SHIFTING TO CENTRAL MN BY DAYBREAK TUESDAY...AND SLOWLY ACROSS LAKE SUPERIOR/UPPER MI TUESDAY. THE APEX OF THE TROUGH SHOULD BE ACROSS THE CENTER OF THE CWA BY AT 12Z WEDNESDAY...BEFORE PUSHING TO THE LOWER GREAT LAKES DURING THE DAY. THE PROGRESSIVELY S SINKING /RUN TO RUN COMPARISON OVER THE PAST COUPLE OF DAYS/ SFC LOW OVER S MANITOBA AND ND MONDAY MORNING WILL RESULT IN INCREASED SW WINDS ACROSS THE UPPER GREAT LAKES. THE TRACK OF THE SFC LOW IS STILL IN QUESTION...WITH THE 06/18Z RUN OF THE GFS AROUND 6HRS FASTER THAN THE NAM/ECMWF/CANADIAN SOLUTIONS. THE 07/00Z RUN OF THE GFS IS MUCH FARTHER TO THE N...BUT STILL TRACKING A BIT FAST. THE TRACK WILL LIKELY BRING THE SFC LOW OVER W-CENTRAL LAKE SUPERIOR BY 06Z TUESDAY...BEFORE SLIDING NE TO JAMES BAY BY 00Z WEDNESDAY. GIVEN THIS TRACK...THE STRONGEST WINDS WILL LIKELY BE AHEAD OF THE SYSTEM /OUT OF THE SW MONDAY THROUGH MONDAY EVENING/. TEMPERATURE WISE...INCREASED DOWNSLOPE S FLOW WILL BE COUNTERACTED SLIGHTLY BY ADDITIONAL CLOUD COVER MONDAY AFTERNOON NEAR LAKE SUPERIOR. N/NW FLOW WILL RETURN TUESDAY NIGHT BEHIND THE EXITING SFC LOW. 850MB TEMPS OF -5 TO -8C MAY NOT BE ENOUGH TO CREATE MUCH MORE THAN ENHANCED CLOUD COVER NEAR THE LAKE SUPERIOR SHORELINE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE NUDGING IN FROM THE CENTRAL PLAINS WEDNESDAY SHOULD HELP IN PUSHING MUCH OF THE LOW LEVEL MOISTURE TO OUR EAST. IT WILL NOT BE QUITE THAT SIMPLE THOUGH...WITH NW FLOW ALOFT AND A CONTINUATION OF SMALLER SCALE WAVES BRINGING IN ADDITIONAL MOISTURE. THURSDAY THROUGH FRIDAY... YET ANOTHER WAVE LOOKS TO SLIDE IN FROM THE NW THURSDAY OR THURSDAY NIGHT. THE 06/12Z ECMWF WAS APPROX 12 HRS SLOWER THAN THE 06/18Z RUN OF THE GFS WITH THIS WEAKER TROUGH. THE 07/00Z RUNS HAVE NEARLY CORRECTED THIS ISSUE...WITH ONLY MINOR DIFFERENCES. STILL HAVE W TO NW GALES TO 35KTS POSSIBLE OVER CENTRAL AND E LAKE SUPERIOR THURSDAY AFTERNOON AND EVENING. FRIDAY NIGHT THROUGH SATURDAY... HIGH PRESSURE WILL ATTEMPT TO BUILD IN AT 500MB...WITH LITTLE MORE THAN ZONAL FLOW BEING THE RESULT...AS THE NEXT LOW NEAR THE 4-CORNERS GETS SWEPT UP IN THE MAIN FLOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 137 PM EDT SUN OCT 7 2012 INTERVALS OF MID/HI CLDS THROUGH MIDDAY MONDAY BUT VFR CONDITIONS WL PREVAIL AT ALL 3 SITES WITH W WIND ADVECTING DRY LLVL AIR INTO THE UPR GRT LKS. PLAN ON SOME MARGINAL LLWS CONDITIONS TNGT WITH DVLPG RADIATION INVRN/DECOUPLING SFC WIND. SOME RAIN SHOWERS ARE EXPECTED LATER MONDAY AFTERNOON BEYOND THIS TAF PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 503 AM EDT SUN OCT 7 2012 AS A HI PRES RIDGE BUILDS TOWARD THE OHIO RIVER VALLEY THRU TONIGHT AND LO PRES MOVES SE THRU CANADA TOWARD MINNESOTA...EXPECT A STRENGTHENING W WIND OVER LAKE SUPERIOR. AS IS TYPICAL FOR THIS FLOW...THE STRONGEST WINDS UP TO 30 KTS ARE MOST LIKELY IN THE AREA BETWEEN THE KEWEENAW AND ISLE ROYALE...WHERE SOME GALE FORCE GUSTS TO 35 KTS ARE POSSIBLE LATER TODAY. LOW PRESSURE NEARING FROM SOUTH CENTRAL CANADA WILL RESULT IN INCREASING SOUTHWESTERLY WINDS MONDAY /WITH S GALES TO 35KTS OVER PORTIONS OF E LAKE SUPERIOR MONDAY INTO MONDAY EVENING/. EXPECT THE LOW TO TRACK FROM ND AND SOUTHERN MANITOBA TO W LS BY LATE MONDAY AFTERNOON INTO MONDAY EVENING. THE LOW WILL PUSH NE TUESDAY...AS ANOTHER DRYING HIGH PRESSURE SYSTEM ATTEMPTS TO BUILD IN FROM THE CENTRAL PLAINS. GUSTS WILL DIMINISH TO 20-25KTS TUESDAY NIGHT. YET ANOTHER LOW SHOULD SKIRT ACROSS OR JUST NORTH OF LAKE SUPERIOR WEDNESDAY NIGHT...WITH WINDS BRIEFLY INCREASING WITH GUSTS NEARING 30KTS AGAIN WEDNESDAY OUT OF THE NW. HIGH PRESSURE SHOULD FINALLY WIN OUT TOWARD THE END OF THE WORK WEEK...WITH ANOTHER ROUND OF WEST TO NORTHWEST GALES TO 35KTS POSSIBLE THURSDAY AFTERNOON AND EVENING...IN BETWEEN NEARING HIGH PRESSURE TO OUR W AND EXITING LOW PRESSURE TO THE E. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR LSZ267. LAKE MICHIGAN... GALE WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING FOR LMZ248-250. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...JLA MARINE...KC/KF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
255 PM EDT SUN OCT 7 2012 .SYNOPSIS... COOL AND DRY WEATHER IS EXPECTED THROUGH EARLY AFTERNOON. RAIN WILL OVERSPREAD THE AREA BY LATE TODAY BEFORE ENDING EARLY TONIGHT. OUR SKY WILL CLEAR OUT TONIGHT AND THIS MAY ALLOW FOR SOME AREAS OF FROST TO FORM BY EARLY MONDAY MORNING. MOSTLY DRY WEATHER IS EXPECTED MONDAY AND TUESDAY BEFORE OUR NEXT SHOT AT WIDESPREAD RAIN COMES WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... 10 AM UPDATE... HV UPDATED GRIDS TO RMV POPS ACRS THE FAVORED LK EFFECT LOCATIONS AS SHOWERS HV WEAKENED RAPIDLY THIS MRNG. HV ALSO RMVD SLGT CHC POPS OVR THE SE AFT 18Z AS AIRMASS WL LKLY TAKE AWHILE TO SATURATE DOWN, WITH MAINLY VIRGA EXPECTED BTWN 18Z-21Z. H5 TROF WL APPRCH FM THE WEST AFT 21Z, RESULTING IN WIDESPREAD PCPN BREAKING OUT ACRS THE CWA. HV TWEAKED HRLY T/TD GRIDS TO COME INTO LINE WITH CURRENT OBS. WL EVALUATE POTENTIAL FOR FROST/FREEZE TONIGHT WITH LATEST MODEL DATA. PREVIOUS DISCUSSIONS BLO... 700 AM UPDATE... THE BAND OF LAKE EFFECT RAIN EAST OF LAKE ONTARIO IS FINALLY SHOWING A SOUTHWARD PUSH WHILE WEAKENING RAPIDLY. WILL CONFINE CHANCE POPS TO NORTH CENTRAL ONEIDA COUNTY AND EXTREME NORTHERN ONONDAGA COUNTY THROUGH 15Z BEFORE KEEPING A DRY FORECAST. A DEVELOPING AREA OF RAIN OVER SOUTH CENTRAL PA STILL LOOKS TO SKIRT JUST SOUTHEAST OF OUR CWA BUT STILL FEEL SLIGHT CHANCE POPS PRUDENT FOR NEPA AS A BUFFER. STILL LOOKING AT THE MAIN THREAT OF RAIN TO COME AFTER 21Z TODAY WITH THE DISTURBANCE MOVING THROUGH IL. 430 AM UPDATE... TODAY....A BAND OF LAKE EFFECT RAIN CONTINUES ACROSS CENTRAL OSWEGO COUNTY AND NORTHERN ONEIDA COUNTY. THE BAND HAS ACTUALLY SHOWN SOME SIGNS OF BECOMING MORE HEALTHY AND HAS PENETRATED FARTHER INLAND IN JUST THE LAST HOUR. HIGHER RESOLUTION MODELS SUCH AS THE HRRR AND THE 4KM NAM WHICH WERE DOING WELL WITH THE PLACEMENT OF THE BAND LATE LAST NIGHT...ARE MUCH TOO WEAK AND TOO FAR SOUTH WITH THE BAND AS OF 09Z. BASED ON THIS CONTINUED TO KEEP HIGH CHANCE POPS ACROSS NORTHERN ONEIDA COUNTY THROUGH 12Z...BEFORE GRADUALLY SHOWING A WEAKENING TREND AS BOUNDARY LAYER WINDS DIMINISH (BAND RETREATS TOWARD LAKE) AND THE FLOW TURNS MORE INTO THE SOUTHWEST. EXPECT ACTIVITY TO DIE DOWN COMPLETELY IN OUR AREA BY 15Z. MEANWHILE FOR THE REST OF US INCREASING HIGH CLOUDS NOW ARE MORE OF A BARK THEN A BITE FOR OUR AREA WITH A UPPER LEVEL JET MOVING OVERHEAD NOW...BUT THE BEST LIFT BEING OFF TO OUR SOUTH AND EAST. KEPT SLIGHT CHANCE POPS IN FOR THE FAR SE CWA IN THE 15Z - 18Z TIME FRAME AS MOST OF THE MODEL GUIDANCE BRINGS POPS INTO INTO EASTERN PA AND NORTHERN NJ...BUT STAYING SOUTH OF THE REGION. A MUCH BETTER SHOT AT RAIN...WIDESPREAD FOR A FEW HOURS...WILL COME WITH A DISTURBANCE IN THE JET STREAM WINDS ALOFT NOW OVER WESTERN IL. RAIN CHANCES WILL INCREASE RAPIDLY BETWEEN 21Z AND 0Z WITH ALL BUT AREAS NORTH OF THE THRUWAY IN LIKELY TO CAT POPS...WITH CHANCE POPS FAR NORTH TONIGHT...RAIN QUICKLY ENDS BY 03Z ACROSS MOST OF THE CWA WITH SOME LAKE EFFECT ACTIVITY (RAIN) POSSIBLE AFTER 06Z UP NORTH. BIGGEST CONCERN HOWEVER IS THE POTENTIAL FOR FROST/FREEZE CONDITIONS. MAV/MET GUIDANCE IS SHOWING 30 AT KELM AND THIS HAS BEEN CONSISTENT OVER THE PAST 24 HOURS. DESPITE SUCH COLD MOS NUMBERS...ELECTED TO HOLD OFF ON ANY ADVISORIES OR WARNINGS AS CONFIDENCE IS NOT QUITE HIGH ENOUGH AT THE MOMENT. CONCERNS INCLUDE THE TIMING ON WHEN WE ACTUALLY CLEAR OUT AND WHETHER OR NOT WE FOG IN OR SEE LOW CLOUDS REDEVELOP GIVEN THE WET GROUND FROM THE RAIN LATER TODAY. WILL LET THE DAY SHIFT REEVALUATE ON ANY HEADLINES AND CONTINUE TO HIGHLIGHT IN THE HWO. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... 430 AM UPDATE... MONDAY/TUESDAY....HIGH PRESSURE MOVING OUT OF THE OHIO VALLEY SHOULD KEEP MOST OF THIS PERIOD DRY BUT MODEL TRENDS ARE POINTING TO SOME UNCERTAINTY STARTING TUESDAY. ANY LAKE SHOWERS EARLY MONDAY MORNING SHOULD QUICKLY DIMINISH WITH RISING HEIGHTS BY LATE MORNING. FROST/FREEZE CONDITIONS MAY BE POSSIBLE AGAIN MONDAY NIGHT...DEPENDING ON THE AMOUNT OF INCREASING CLOUD COVER WE MAY SEE ESPECIALLY FAR SOUTHEAST. THE MODELS SHOW ANOTHER AREA OF MOISTURE MOVING THROUGH THE MID- ATLANTIC STATES...VERY SIMILAR TO WHAT WILL MISS US EARLY TODAY...LATER MONDAY AND MONDAY NIGHT. AGAIN THE BEST LIFT APPEARS TO BE JUST SOUTH AND EAST OF US AND WILL KEEP OUR AREA DRY THROUGH MONDAY NIGHT. AS THIS MOISTURE SLIDES EAST...HIGH PRESSURE MENTIONED ABOVE WILL MOVE OFF THE COAST OF MAINE. THIS WILL HELP TO DEVELOP AN ONSHORE FLOW AND WILL BEGIN TO PUSH MOISTURE BACK TOWARD THE COAST STARTING TUESDAY....ESPECIALLY LATER IN THE DAY. THE GFS AND EURO HINT AT THIS...BUT KEEP PRECIP MAINLY FROM THE HUDSON VALLEY SOUTH AND EAST...WHILE THE NAM IS A BIT FARTHER WEST. FOR NOW WILL PLAY SLIGHT CHANCE POPS TUESDAY FOR LATER IN THE DAY INTO TUESDAY NIGHT GIVEN THE UNCERTAINTY. && .LONG TERM /THURSDAY THROUGH SATURDAY/... AN UNSETTLED EXTENDED TIMEFRAME CONTINUES TO TAKE SHAPE THIS AFTERNOON AS REGION WILL RESIDE UNDER THE ACTIVE POLAR JET THROUGH A GOOD PORTION OF THE PERIOD. THAT SAID...EXPECT ONGOING LAKE EFFECT SHWR ACTIVITY LATE WED/EARLY THU ACROSS THE SOUTHERN TUG HILL AS REGION WILL RESIDE ON A POST FRONTAL AIRMASS. NEXT NORTHERN STREAM TROUGH EXPECTED TO DROP SOUTH ACROSS THE AREA THU NIGHT/EARLY FRI WHICH WILL LEAD TO BELOW NORMAL TEMPS BY FRI AS COOL CANADIAN HIGH PRESSURE TEMPORARILY SETTLES ACROSS THE REGION. MODEL PROGGED H85 TEMPS APPROACH -6C BY FRI AFTERNOON AND THUS EXPECT THE REGENERATION OF LAKE EFFECT SHWRS SOUTHEAST OF LAKE ONTARIO. BEYOND THIS...STRONG WARM AIR ADVECTION EXPECTED BY THE BEGINNING OF THE WEEKEND AS CENTRAL PLAINS DISTURBANCE BEGINS LIFTING NORTH TOWARDS THE CENTRAL GREAT LAKES. FOR NOW...BEST CHANCES OF WARM ADVECTION SHWRS EXPECTED ON SATURDAY AS WARM FRONT LIFTS NORTH TOWARDS THE AREA. THE SLOW MOVEMENT OF THE FEATURE MAY THEN KEEP THE CHANCE FOR SHWRS IN THE FCST THROUGH THE CONCLUSION OF THE PERIOD. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... UPSTREAM RADARS SHOWING AN AREA OF -SHRA ACTIVITY ASSOCIATED WITH A SHORTWAVE TROUGH HEADING TOWARDS OUR REGION EARLY THIS AFTERNOON. EXPECT THIS ACTIVITY TO MOVE IN AFTER 20Z WITH ALL TERMINALS EXPECTED TO FALL TO MVFR THRESHOLDS AS MAIN PRECIP SHIELD PASSES. SOME POTENTIAL FOR SHORT DURATION IFR CIGS AT BOTH ITH AND BGM AS THIS ACTIVITY ROLES THROUGH...HOWEVER CONFIDENCE AT THIS TIME IS NOT HIGH ENOUGH TO INCLUDE IN THE CURRENT FCST. ACTIVITY WILL QUICKLY EXIT TOWARDS THE NORTHEAST AFTER 02-03Z TIME FRAME WITH LAKE EFFECT SHWRS THEN EXPECTED TO DEVELOP SOUTHEAST OF LAKE ONTARIO AFTER 04Z. 280-290 FLOW WILL LIKELY RESULT IN LAKE CLOUDS AND POSSIBLE SHWR ACTIVITY AT RME...WITH LAKE CLOUDS ALSO POSSIBLE AT SYR. FURTHER SOUTH...FCST MODELS SUGGEST CLEARING WILL OCCUR AFTER 06Z AT ELM/BGM/AVP AND POSSIBLY ITH. WITH MOIST LOW-LEVEL CONDITIONS ASSOCIATED WITH THIS AFTERNOON/S RAINFALL...THE POTENTIAL EXISTS FOR DEVELOPING IFR CIGS AND VSBYS AFTER 06Z AT THE ABOVE SITES. BEYOND 13Z...BUILDING HIGH PRESSURE WILL BREAKUP ANY LINGERING LOW CIGS WITH VFR CONDITIONS EXPECTED THROUGH THE DURATION OF THE FCST. OUTLOOK... MON AFTERNOON/TUE...VFR. WED...MAINLY VFR WITH POSSIBLE MVFR LATE IN DEVELOPING SHWRS. THU...MOSTLY VFR WITH POSSIBLE MVFR AT RME IN DEVELOPING LAKE EFFECT SHWRS. FRI...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...HEDEN/PVN NEAR TERM...HEDEN/PVN SHORT TERM...HEDEN LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
151 PM EDT SUN OCT 7 2012 .SYNOPSIS... COOL AND DRY WEATHER IS EXPECTED THROUGH EARLY AFTERNOON. RAIN WILL OVERSPREAD THE AREA BY LATE TODAY BEFORE ENDING EARLY TONIGHT. OUR SKY WILL CLEAR OUT TONIGHT AND THIS MAY ALLOW FOR SOME AREAS OF FROST TO FORM BY EARLY MONDAY MORNING. MOSTLY DRY WEATHER IS EXPECTED MONDAY AND TUESDAY BEFORE OUR NEXT SHOT AT WIDESPREAD RAIN COMES WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... 10 AM UPDATE... HV UPDATED GRIDS TO RMV POPS ACRS THE FAVORED LK EFFECT LOCATIONS AS SHOWERS HV WEAKENED RAPIDLY THIS MRNG. HV ALSO RMVD SLGT CHC POPS OVR THE SE AFT 18Z AS AIRMASS WL LKLY TAKE AWHILE TO SATURATE DOWN, WITH MAINLY VIRGA EXPECTED BTWN 18Z-21Z. H5 TROF WL APPRCH FM THE WEST AFT 21Z, RESULTING IN WIDESPREAD PCPN BREAKING OUT ACRS THE CWA. HV TWEAKED HRLY T/TD GRIDS TO COME INTO LINE WITH CURRENT OBS. WL EVALUATE POTENTIAL FOR FROST/FREEZE TONIGHT WITH LATEST MODEL DATA. PREVIOUS DISCUSSIONS BLO... 700 AM UPDATE... THE BAND OF LAKE EFFECT RAIN EAST OF LAKE ONTARIO IS FINALLY SHOWING A SOUTHWARD PUSH WHILE WEAKENING RAPIDLY. WILL CONFINE CHANCE POPS TO NORTH CENTRAL ONEIDA COUNTY AND EXTREME NORTHERN ONONDAGA COUNTY THROUGH 15Z BEFORE KEEPING A DRY FORECAST. A DEVELOPING AREA OF RAIN OVER SOUTH CENTRAL PA STILL LOOKS TO SKIRT JUST SOUTHEAST OF OUR CWA BUT STILL FEEL SLIGHT CHANCE POPS PRUDENT FOR NEPA AS A BUFFER. STILL LOOKING AT THE MAIN THREAT OF RAIN TO COME AFTER 21Z TODAY WITH THE DISTURBANCE MOVING THROUGH IL. 430 AM UPDATE... TODAY....A BAND OF LAKE EFFECT RAIN CONTINUES ACROSS CENTRAL OSWEGO COUNTY AND NORTHERN ONEIDA COUNTY. THE BAND HAS ACTUALLY SHOWN SOME SIGNS OF BECOMING MORE HEALTHY AND HAS PENETRATED FARTHER INLAND IN JUST THE LAST HOUR. HIGHER RESOLUTION MODELS SUCH AS THE HRRR AND THE 4KM NAM WHICH WERE DOING WELL WITH THE PLACEMENT OF THE BAND LATE LAST NIGHT...ARE MUCH TOO WEAK AND TOO FAR SOUTH WITH THE BAND AS OF 09Z. BASED ON THIS CONTINUED TO KEEP HIGH CHANCE POPS ACROSS NORTHERN ONEIDA COUNTY THROUGH 12Z...BEFORE GRADUALLY SHOWING A WEAKENING TREND AS BOUNDARY LAYER WINDS DIMINISH (BAND RETREATS TOWARD LAKE) AND THE FLOW TURNS MORE INTO THE SOUTHWEST. EXPECT ACTIVITY TO DIE DOWN COMPLETELY IN OUR AREA BY 15Z. MEANWHILE FOR THE REST OF US INCREASING HIGH CLOUDS NOW ARE MORE OF A BARK THEN A BITE FOR OUR AREA WITH A UPPER LEVEL JET MOVING OVERHEAD NOW...BUT THE BEST LIFT BEING OFF TO OUR SOUTH AND EAST. KEPT SLIGHT CHANCE POPS IN FOR THE FAR SE CWA IN THE 15Z - 18Z TIME FRAME AS MOST OF THE MODEL GUIDANCE BRINGS POPS INTO INTO EASTERN PA AND NORTHERN NJ...BUT STAYING SOUTH OF THE REGION. A MUCH BETTER SHOT AT RAIN...WIDESPREAD FOR A FEW HOURS...WILL COME WITH A DISTURBANCE IN THE JET STREAM WINDS ALOFT NOW OVER WESTERN IL. RAIN CHANCES WILL INCREASE RAPIDLY BETWEEN 21Z AND 0Z WITH ALL BUT AREAS NORTH OF THE THRUWAY IN LIKELY TO CAT POPS...WITH CHANCE POPS FAR NORTH TONIGHT...RAIN QUICKLY ENDS BY 03Z ACROSS MOST OF THE CWA WITH SOME LAKE EFFECT ACTIVITY (RAIN) POSSIBLE AFTER 06Z UP NORTH. BIGGEST CONCERN HOWEVER IS THE POTENTIAL FOR FROST/FREEZE CONDITIONS. MAV/MET GUIDANCE IS SHOWING 30 AT KELM AND THIS HAS BEEN CONSISTENT OVER THE PAST 24 HOURS. DESPITE SUCH COLD MOS NUMBERS...ELECTED TO HOLD OFF ON ANY ADVISORIES OR WARNINGS AS CONFIDENCE IS NOT QUITE HIGH ENOUGH AT THE MOMENT. CONCERNS INCLUDE THE TIMING ON WHEN WE ACTUALLY CLEAR OUT AND WHETHER OR NOT WE FOG IN OR SEE LOW CLOUDS REDEVELOP GIVEN THE WET GROUND FROM THE RAIN LATER TODAY. WILL LET THE DAY SHIFT REEVALUATE ON ANY HEADLINES AND CONTINUE TO HIGHLIGHT IN THE HWO. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... 430 AM UPDATE... MONDAY/TUESDAY....HIGH PRESSURE MOVING OUT OF THE OHIO VALLEY SHOULD KEEP MOST OF THIS PERIOD DRY BUT MODEL TRENDS ARE POINTING TO SOME UNCERTAINTY STARTING TUESDAY. ANY LAKE SHOWERS EARLY MONDAY MORNING SHOULD QUICKLY DIMINISH WITH RISING HEIGHTS BY LATE MORNING. FROST/FREEZE CONDITIONS MAY BE POSSIBLE AGAIN MONDAY NIGHT...DEPENDING ON THE AMOUNT OF INCREASING CLOUD COVER WE MAY SEE ESPECIALLY FAR SOUTHEAST. THE MODELS SHOW ANOTHER AREA OF MOISTURE MOVING THROUGH THE MID- ATLANTIC STATES...VERY SIMILAR TO WHAT WILL MISS US EARLY TODAY...LATER MONDAY AND MONDAY NIGHT. AGAIN THE BEST LIFT APPEARS TO BE JUST SOUTH AND EAST OF US AND WILL KEEP OUR AREA DRY THROUGH MONDAY NIGHT. AS THIS MOISTURE SLIDES EAST...HIGH PRESSURE MENTIONED ABOVE WILL MOVE OFF THE COAST OF MAINE. THIS WILL HELP TO DEVELOP AN ONSHORE FLOW AND WILL BEGIN TO PUSH MOISTURE BACK TOWARD THE COAST STARTING TUESDAY....ESPECIALLY LATER IN THE DAY. THE GFS AND EURO HINT AT THIS...BUT KEEP PRECIP MAINLY FROM THE HUDSON VALLEY SOUTH AND EAST...WHILE THE NAM IS A BIT FARTHER WEST. FOR NOW WILL PLAY SLIGHT CHANCE POPS TUESDAY FOR LATER IN THE DAY INTO TUESDAY NIGHT GIVEN THE UNCERTAINTY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MEDIUM RANGE MODELS MAINTAIN SOME CONSISTENCY WITH INDICATIONS OF BEST SHOT OF PRECIPITATION ACROSS THE ENTIRE REGION DURING THIS PERIOD TO BE IN THE WEDNESDAY TIME FRAME. THIS IS THEN LIKELY TO BE FOLLOWED BY DEEPENING COLD AIR AND A MAINTAINED PRESENCE OF SHOWER CHANCES TO THE LEE OF LAKE ONTARIO THROUGH THURSDAY WITH IMPROVED WX OVER THE SOUTHERN HALF. ANOTHER WEAK UPPER TROF AND SFC FRONT MAY SPREAD A QUICK SHOT OF SHOWERS INTO THE AREA ON FRIDAY. A FAIRLY LARGE CENTER OF CONTINENTAL POLAR...FALL- LIKE...HIGH PRESSURE WORKS IN FOR AT LEAST THE FIRST HALF OF NEXT WEEKEND. FOLLOWED THE HPC DAY 3-7 GUIDANCE CLOSELY WITH ONLY MINOR LOCAL ADJUSTMENTS TO TEMPERATURES. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... UPSTREAM RADARS SHOWING AN AREA OF -SHRA ACTIVITY ASSOCIATED WITH A SHORTWAVE TROUGH HEADING TOWARDS OUR REGION EARLY THIS AFTERNOON. EXPECT THIS ACTIVITY TO MOVE IN AFTER 20Z WITH ALL TERMINALS EXPECTED TO FALL TO MVFR THRESHOLDS AS MAIN PRECIP SHIELD PASSES. SOME POTENTIAL FOR SHORT DURATION IFR CIGS AT BOTH ITH AND BGM AS THIS ACTIVITY ROLES THROUGH...HOWEVER CONFIDENCE AT THIS TIME IS NOT HIGH ENOUGH TO INCLUDE IN THE CURRENT FCST. ACTIVITY WILL QUICKLY EXIT TOWARDS THE NORTHEAST AFTER 02-03Z TIME FRAME WITH LAKE EFFECT SHWRS THEN EXPECTED TO DEVELOP SOUTHEAST OF LAKE ONTARIO AFTER 04Z. 280-290 FLOW WILL LIKELY RESULT IN LAKE CLOUDS AND POSSIBLE SHWR ACTIVITY AT RME...WITH LAKE CLOUDS ALSO POSSIBLE AT SYR. FURTHER SOUTH...FCST MODELS SUGGEST CLEARING WILL OCCUR AFTER 06Z AT ELM/BGM/AVP AND POSSIBLY ITH. WITH MOIST LOW-LEVEL CONDITIONS ASSOCIATED WITH THIS AFTERNOON/S RAINFALL...THE POTENTIAL EXISTS FOR DEVELOPING IFR CIGS AND VSBYS AFTER 06Z AT THE ABOVE SITES. BEYOND 13Z...BUILDING HIGH PRESSURE WILL BREAKUP ANY LINGERING LOW CIGS WITH VFR CONDITIONS EXPECTED THROUGH THE DURATION OF THE FCST. OUTLOOK... MON AFTERNOON/TUE...VFR. WED...MAINLY VFR WITH POSSIBLE MVFR LATE IN DEVELOPING SHWRS. THU...MOSTLY VFR WITH POSSIBLE MVFR AT RME IN DEVELOPING LAKE EFFECT SHWRS. FRI...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...HEDEN/PVN NEAR TERM...HEDEN/PVN SHORT TERM...HEDEN LONG TERM...JAB AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1257 PM CDT SUN OCT 7 2012 .DISCUSSION...NO MAJOR UPDATES WERE REQUIRED TO THE ONGOING FORECAST. THE 14Z HRRR CONTINUES TO BE THE MOST AGGRESSIVE MODEL SHOWING PRECIP ACTIVITY DEVELOPING INITIALLY ALONG THE WARM FRONT AND MOVING INTO WESTERN NORTH DAKOTA LATER THIS AFTERNOON. THE 12Z GFS IS BECOMING MORE AGGRESSIVE WITH ITS PROG OF PRECIP WEST. HOWEVER...IT IS SLOWER WITH ITS PROGRESSION. ON THE OTHER HAND...THE 12Z NAM IS COMPLETELY DRY WITH ITS PROG AREAWIDE THROUGH 06Z MONDAY. WITH THAT BEING SAID...SIDED WITH A GFS (WHICH IS A PROXY FOR A MODEL BLEND) TO FORECAST 20 POPS NORTHWEST FROM 21Z- 24Z SUNDAY...THEN EXPANDED SLIGHT CHANCE POPS SOUTH AND EAST FROM 00Z-06Z MONDAY. NO MAJOR IMPACTS ARE EXPECTED. THE UPDATED GRIDDED AND TEXT PRODUCTS WILL BE OUT SHORTLY. && .AVIATION...LOW PRESSURE OUT OF CANADA WILL BEGIN TO MOVE SOUTH INTO THE REGION LATE TONIGHT EARLY TOMORROW MORNING. EXPECT SOME SCATTERED SHOWERS FROM THIS SYSTEM WITH THE BEST CHANCES NORTH AT SITES ISN AND MOT AFTER 00Z. LOW CEILINGS JUST ABOVE THE MVFR RANGE WILL MOVE IN FROM NORTH TO SOUTH AROUND 10Z. CEILINGS COULD GO LOWER INTO THE MVFR CATEGORY. HOWEVER...THIS WILL BE REVISITED IN LATER TAFS. VFR CONDITIONS ARE EXPECTED THROUGH THE 18Z TAF CYCLE. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TM...UPDATE JWS/MM...AVIATION
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
303 PM CDT SUN OCT 7 2012 .SHORT TERM...TONIGHT THROUGH WEDNESDAY 303 PM CDT SUN OCT 7 2012 MAIN FORECAST CONCERNS ARE ON FIRE WEATHER FOR MONDAY AND PRECIPITATION CHANCES MONDAY NIGHT INTO TUESDAY. CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS LOOKS SIMILAR TO YESTERDAY WITH RIDGING OVER THE NORTHEAST PACIFIC...AND DEEP TROUGHING OVER CENTRAL AND EASTERN CANADA EXTENDING SOUTH INTO THE CENTRAL PLAINS AND OHIO VALLEY. THE MAIN FEATURES OF NOTE ARE ON THE WEST SIDE OF THE TROUGHING...WHICH INCLUDE A WEAK SHORTWAVE TROUGH ENTERING THE FORECAST AREA NOW...WITH A STRONGER SHORTWAVE IN CENTRAL SASKATCHEWAN. ONLY A FEW HIGH CLOUDS WERE ACCOMPANYING THE SHORTWAVE TROUGH CROSSING THE FORECAST AREA. REGARDING THE SASKATCHEWAN SHORTWAVE... A LARGE EXPANSE OF MID AND HIGH CLOUDS ENCOMPASSED MUCH OF SASKATCHEWAN. AT THE SURFACE...PRESSURE GRADIENT HAS TIGHTENED ACROSS THE NORTHERN PLAINS AND THE FORECAST AREA...AHEAD OF A 1002MB LOW IN CENTRAL SASKATCHEWAN. THE BREEZY SOUTHWEST WINDS ARE GRADUALLY WARMING THINGS...WITH RAP 850MB TEMPS AT MPX NOW AROUND 0C COMPARED TO -5C PER 12Z SOUNDING. AIRMASS QUITE DRY TOO WITH MPX SOUNDING SHOWING 0.18 INCHES OF PRECIPITABLE WATER OR 30 PERCENT OF NORMAL. TONIGHT AND MONDAY...MODELS ARE IN MUCH BETTER AGREEMENT HANDLING THE SHORTWAVE DROPPING DOWN OUT OF SASKATCHEWAN...TRACKING IT TO NEAR INTERNATIONAL FALLS MN BY 00Z TUESDAY. CO-LOCATED NEARLY RIGHT UNDERNEATH IT WILL BE THE SURFACE LOW...PROGGED TO DEEPEN SLIGHTLY...WITH ITS COLD FRONT APPROACHING MINNEAPOLIS AND SIOUX CITY IOWA AT 00Z TUESDAY. TIGHT PRESSURE GRADIENT FORECAST TO STAY PUT OVER THE FORECAST AREA THROUGH MONDAY...EXPECTED TO GET EVEN STRONGER...AS THE FRONT APPROACHES. NOCTURNAL COOLING MAY ALLOW WINDS TO DIMINISH SOME TONIGHT...ESPECIALLY AT THE TYPICAL COLD SPOTS...BUT ANTICIPATING BREEZY CONDITIONS TO QUICKLY DEVELOP MONDAY MORNING WITH THE ONSET OF DIURNAL HEATING. FORECAST SOUNDINGS SHOW MIXING ANYWHERE FROM 850MB TO 800MB WHERE A WIND CORE OF 35-40 KT IS PRESENT. THUS GUSTS UPWARDS OF 30 KT ARE POSSIBLE. REGARDING THE MIXING...IT IS INTERESTING TO SEE THE DEPTH GIVEN WHAT WILL LIKELY BE A LOT OF CLOUD COVER. 700MB RH FIELDS FROM THE 07.12Z GFS/NAM/ECMWF/CANADIAN ALL DEPICT THE CURRENT ALTOSTRATUS ACROSS SASKATCHEWAN SPREADING ACROSS AT LEAST THE NORTHERN 2/3 OF THE FORECAST AREA DURING THE DAY MONDAY. IN FACT...THE GFS CONTINUES TO HINT AT EVEN PRECIPITATION FROM TAYLOR COUNTY NORTHWARD COMING OUT OF THIS MID CLOUD DECK. GIVEN ALL OTHER MODELS DRY AND THE DEEP MIXING...WILL KEEP A DRY FORECAST GOING. REGARDING HIGH TEMPERATURES ON MONDAY...THE SOUTHWEST WINDS WILL HELP PROPEL 850MB TEMPS UP TO 4-6C BY 18Z...ALLOWING MOST LOCATIONS TO TOP OUT IN THE 60S. TAYLOR COUNTY MAY GET STUCK IN THE 50S...THOUGH...DUE TO THICKER CLOUD COVER PRESENT MUCH OF THE DAY. COMBINATION OF THE WINDS... TEMPERATURES...ONGOING DROUGHT AND DRY CONDITIONS LEADING TO FIRE WEATHER CONCERNS. SEE FIRE WEATHER DISCUSSION BELOW. LOWS TONIGHT SHOULD MAINLY BE IN THE 30S...KEPT UP BY THE WINDS. SOME CONCERN ABOUT A FROST/FREEZE IN FAR SOUTHWEST WISCONSIN...BUT TEMPERATURES MAY END UP RIGHT AROUND 32F AND RELATIVE HUMIDITIES DO NOT GET HIGH ENOUGH TO SUPPORT FROST FORMATION. MONDAY NIGHT AND TUESDAY...IMMEDIATELY IN THE WAKE OF THE SASKATCHEWAN SHORTWAVE...MODELS PROG ANOTHER SHORTWAVE WHICH LOOKS MORE POTENT DROPPING DOWN INTO THE DAKOTAS MONDAY NIGHT...THEN ENTERING THE WESTERN PORTION OF THE FORECAST AREA ON TUESDAY. THIS SHORTWAVE IS CURRENTLY IN THE NORTHWEST TERRITORIES. THE SHORTWAVE LOOKS TO SLOW DOWN THE COLD FRONTAL PASSAGE INITIALLY...SINCE IT CAUSES THE UPPER FLOW TO TURN PARALLEL. NOT UNTIL TUESDAY DOES THE FRONT GET A BETTER PUSH EAST ACROSS THE FORECAST AREA...IN RESPONSE TO THE SHORTWAVE APPROACHING. THUS...MONDAY NIGHT SHOULD STAY RELATIVELY MILD COMPARED TO WHAT WE HAVE SEEN WITH LOWS IN THE 40S. BIGGER ISSUE THOUGH IS IF ANY PRECIPITATION CAN OCCUR. THERE IS SOME LOW TO MID LEVEL FRONTOGENESIS THAT DEVELOPS IN THE WAKE OF THE COLD FRONT MONDAY NIGHT. HOWEVER...MODELS ARE PRETTY DRY WITH ONLY HINTS OF A LITTLE LIGHT QPF BETWEEN 06-12Z TUESDAY IN A NARROW BAND. THIS IS LIKELY DUE TO A COMBINATION OF THE FORCING NOT THAT STRONG AND PRECIPITABLE WATER VALUES WHICH ARE JUST CLIMBING TO 0.75 OF AN INCH AT 12Z. TUESDAY IS A DIFFERENT STORY...WITH THE MORE POTENT SHORTWAVE APPROACHING. THIS SHORTWAVE ENHANCES THE FRONTOGENESIS CIRCULATION AND NOW THE HIGHER PRECIPITABLE WATER IS IN PLACE. ALL MODELS DEVELOP A BAND OF LIGHT TO POSSIBLY EVEN MODERATE RAIN BY THE AFTERNOON ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA. GIVEN THE POTENCY OF THE SHORTWAVE...THIS CERTAINLY SEEMS POSSIBLE. THEREFORE...HAVE RAISED PRECIPITATION CHANCES WITH A MAX OF 60 IN THE SOUTHEASTERN HALF. WITH PLENTY OF CLOUDS...COLD FRONTAL PASSAGE AND POTENTIAL FOR PRECIPITATION...STAYED ON THE COOLER OF GUIDANCE FOR HIGHS. TUESDAY NIGHT AND WEDNESDAY...THE POTENT SHORTWAVE APPROACHING THE FORECAST AREA AT 00Z WEDNESDAY LOOKS TO MOVE THROUGH FAIRLY QUICKLY...PERHAPS REACHING LAKE MICHIGAN BY 06Z. THE ENHANCED FRONTOGENESIS BAND COULD STILL BE OVER THE SOUTHEASTERN 1/3 OF THE FORECAST AREA IN THE EVENING...AS SUGGESTED BY THE 07.00Z ECMWF... SO HAVE MAINTAINED A 20-30 PERCENT CHANCE OF PRECIPITATION. AFTER THAT...STRONG SUBSIDENCE AND DRYING COMES IN ALOFT...WHICH MAY TRAP SOME LOW CLOUDS ALONG/EAST OF THE MISSISSIPPI RIVER. SURFACE RIDGE AXIS STILL WELL TO THE WEST TUESDAY NIGHT...ONLY REACHING WESTERN MINNESOTA BY 12Z WEDNESDAY...FAVORING TOO THE CLOUDS TO STAY IN PLACE. COMBINATION OF DAYTIME MIXING AND THE SURFACE RIDGE AXIS CROSSING THE AREA ON WEDNESDAY WILL HELP TO DISSIPATE THE CLOUDS. HAVE INCREASED CLOUD COVER BUT MAY NEED FURTHER INCREASES... PARTICULARLY IN WISCONSIN WHICH IS MORE IN CYCLONIC LOW LEVEL FLOW. 850MB TEMPS DROP QUITE A BIT ON TUESDAY NIGHT...FALLING FROM 0-4C AT 00Z TO -2 TO -4C AT 12Z. HOWEVER...A NORTHERLY BREEZE ON THE EAST SIDE OF THE RIDGE AXIS PLUS CLOUDS MAY END UP HOLDING TEMPERATURES UP HIGHER THAN GUIDANCE. AS SUCH...LEANED A LITTLE WARMER THAN WHAT GUIDANCE SHOWED WITH LOWS MAINLY IN THE LOW 30S. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY 303 PM CDT SUN OCT 7 2012 07.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES REMAIN IN GOOD AGREEMENT ON THE PATTERN CHANGE FORECAST THE PAST FEW DAYS. ONE MORE SHORTWAVE TROUGH IS FORECAST TO DROP DOWN THROUGH THE DEEP TROUGHING... CROSSING LAKE SUPERIOR ON THURSDAY. THIS SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT LOOK TO COME THROUGH DRY...WITH YET ANOTHER CANADIAN HIGH PRESSURE AREA BUILDING IN FOR FRIDAY. AFTER THAT...THE RIDGING OVER THE NORTHEAST PACIFIC...AS WELL AS AN UPPER LOW CURRENTLY OFF THE CALIFORNIA COAST...GET PUSHED TO THE EAST. MODEL HANDLING YESTERDAY WAS PROBLEMATIC WITH THE UPPER LOW...BUT NOW ALL MODELS ARE IN SYNC IN LIFTING IT OUT OF THE SOUTHWESTERN U.S. INTO NEBRASKA BY 12Z SATURDAY. STRONG 850MB MOISTURE TRANSPORT IS INDICATED AHEAD OF THE UPPER LOW...WHICH SHOULD RESULT IN WIDESPREAD RAIN/SHOWER DEVELOPMENT UPSTREAM TOWARDS THE FORECAST AREA. IN FACT...THERE ARE EVEN SIGNALS OF A COUPLED UPPER JET STRUCTURE TO SET UP OVER THE FORECAST AREA. BEST CHANCES OF PRECIPITATION ARE ON SATURDAY AS THE UPPER LOW AND THE ASSOCIATED LOW PRESSURE SYSTEM LIFT INTO IOWA. HAVE ALSO INCLUDED A MENTION OF THUNDER ON SATURDAY...MAINLY SOUTH OF I-90...WHERE 850MB TEMPS ARE CLIMBING TOWARDS 10-12C AND MUCAPE VALUES TOP OUT BETWEEN 200-500 J/KG. CHANCES OF PRECIPITATION CONTINUE THROUGH SUNDAY...WITH THOSE ON SATURDAY NIGHT RELATED TO DEFORMATION ON THE BACK SIDE OF THE SURFACE LOW PASSING TO OUR SOUTH...THEN WITH A POSSIBLE SHORTWAVE DROPPING DOWN OUT OF CANADA IN THE WAKE OF THE UPPER LOW. TEMPERATURES OVERALL THROUGH MUCH OF THE LONG TERM PERIOD EXPECTED TO STAY BELOW NORMAL...EVEN WITH THAT WARMER AIR COMING UP ON SATURDAY. THE PROBLEM WITH SATURDAY IS THERE WILL LIKELY BE A LOT OF CLOUDS AND THE RAIN AROUND. FOLLOWED THE CONSENSUS WHICH RESULTS IN HIGHS IN THE 50S. COLDEST NIGHT LOOKS TO BE THURSDAY NIGHT AS THAT CANADIAN HIGH BUILDS ALMOST OVERHEAD BY 12Z FRIDAY. LOWS AT OR BELOW FREEZING ARE LIKELY. && .AVIATION...THROUGH 18Z MONDAY 1222 PM CDT SUN OCT 7 2012 VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. WINDS WILL BE ON THE INCREASE LATE TONIGHT INTO MONDAY A SURFACE TROUGH APPROACHES FROM THE DAKOTAS. LOW LEVEL WIND SHEAR IS POSSIBLE LATE TONIGHT INTO EARLY MONDAY MORNING IF SURFACE WINDS DECOUPLE. AT THIS TIME IT APPEARS THAT SOUTHWEST WINDS AT THE SURFACE WILL STAY IN THE 8 TO 13 KT RANGE THROUGH THE NIGHT AT KLSE AND IN THE 10 TO 15 KT RANGE AT KRST. FORECAST SOUNDINGS SHOW SOUTHWEST WINDS INCREASING TO AROUND 42 KTS AT 1500 FT. WITH SURFACE WINDS STAYING UP IT APPEARS THAT WE WILL FALL JUST SHORT OF LOW LEVEL WIND SHEAR CRITERIA SO HAVE NOT INCLUDED IT IN THE TAFS AT THIS TIME. WILL HAVE TO KEEP A CLOSE EYE ON SURFACE WINDS OVERNIGHT. CLOUDS WILL INCREASE LATE TONIGHT INTO MONDAY MORNING...AND BY MONDAY MORNING A BROKEN MID CLOUD DECK WILL BE IN PLACE WITH CLOUD BASES AROUND 9KFT. LOOK FOR THE BREEZY SOUTHWEST WINDS TO CONTINUE MONDAY WITH SPEED OF 15 TO 20 KTS...GUSTING INTO THE 25 TO 30 KT RANGE AT TIMES. && .FIRE WEATHER...MONDAY 327 PM CDT SUN OCT 7 2012 A BREEZY SOUTH WIND TONIGHT...ESPECIALLY WEST OF THE MISSISSIPPI RIVER...WILL HELP PREVENT FULL RELATIVE HUMIDITY RECOVERY TONIGHT GIVEN DEWPOINTS RIGHT NOW IN THE TEENS. MAXIMUM RELATIVE HUMDITY VALUES ARE ONLY EXPECTED TO TOP OUT BETWEEN 60-70 PERCENT AT MOST. THE BREEZY SOUTH TO SOUTHWEST WINDS ARE EXPECTED TO PERSIST INTO THE DAY MONDAY AS LOW PRESSURE DROPS INTO NORTHERN MINNESOTA. SUSTAINED SPEEDS OF 15 TO 25 MPH ARE LIKELY WITH GUSTS OF 30 TO 35 MPH. PLENTY OF CLOUDS ASSOCIATED WITH THE LOW PRESSURE AREA SHOULD OVERSPREAD THE AREA...ESPECIALLY ALONG AND NORTH OF I-90. THIS RESULTS IN SOME ISSUES...PRIMARILY WITH FINE FUELS. HOWEVER...WITH TEMPERATURES WARMING UP INTO THE 60S AND RELATIVE HUMIDITIES DROPPING INTO THE 20-25 PERCENT RANGE WEST OF THE MISSISSIPPI RIVER...VERY CONCERNED ABOUT FIRES. THE ONGOING MODERATE TO EXTREME DROUGHT PLUS MOST OF THE REGION EXPERIENCING A FREEZE ALSO CREATES EXTRA CONCERN FOR FIRES. AFTER COORDINATION WITH MINNESOTA AND IOWA FIRE WEATHER OFFICIALS...HAVE ISSUED A FIRE WEATHER WATCH FOR LOCATIONS WEST OF THE MISSISSIPPI RIVER. EAST OF THE MISSISSIPPI RIVER...MINIMUM RELATIVE HUMIDITIES ONLY DROP TO 25-30 PERCENT. WINDS ARE SLIGHTLY LIGHTER AND TEMPERATURES ARE COOLER. AFTER COORDINATION WITH WISCONSIN FIRE WEATHER OFFICIALS...HAVE DECLINED TO ISSUE ANY FIRE WEATHER WATCH EAST OF THE MISSISSIPPI RIVER. && .ARX WATCHES/WARNINGS/ADVISORIES... 303 PM CDT SUN OCT 7 2012 WI...NONE. MN...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR MNZ079-086>088-094>096. IA...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR IAZ008>011-018-019-029-030. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP FIRE WEATHER...AJ