Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/09/13


AREA FORECAST DISCUSSION
NWS TAUNTON MA
613 PM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING ACCOMPANIED BY BRIEF HEAVY RAIN...GUSTY WINDS AND ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL RESULT IN DRY AND SEASONABLE WEATHER TUE INTO THU AFTERNOON. LOW PRESSURE MAY BRING A BIT OF RAIN AT TIMES THU NIGHT INTO EARLY NEXT WEEK...BUT ONLY IF THE SYSTEM TRACKS FAR ENOUGH NORTH. THERE IS VERY LOW FORECAST CONFIDENCE LATE IN THE WEEK INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 615 PM UPDATE... ***SEVERE THUNDERSTORM WATCH THROUGH 10 PM FOR SOUTHERN NH...WESTERN/CENTRAL MA AS WELL AS NORTHEAST MA AND NORTHERN CT*** NARROW LINE OF HEAVY SHOWERS ALONG WITH POCKETS OF STRONG WIND GUSTS WERE MOVING ACROSS SOUTHWEST NH/WESTERN MA AND NORTHERN CT EARLY THIS EVENING. HRRR MODEL HAS HAD A PRETTY GOOD HANDLE ON THIS ACTIVITY AND EXPECT IT TO CONTINUE TO MOVE EAST OVER THE NEXT FEW HOURS. THE BULK OF THE ACTIVITY SHOULD EXIT THE COASTLINE BY 10 OR 11 PM...ALTHOUGH SHOULD LINGER A BIT LONGER ACROSS THE SOUTHEAST NEW ENGLAND COAST. THERE ALSO COULD BE A FEW LIGHTER SHOWERS LINGERING BEHIND THE MAIN LINE. THIS IS A CLASSIC HIGH SHEAR BUT VERY LOW CAPE ENVIRONMENT. IN FACT...HAVEN/T EVEN SEEN ANY CLOUD TO GROUND LIGHTNING RECENTLY. MAY SEE AN ISOLATED LIGHTNING STRIKE IN THE NEXT HOUR OR TWO...BUT CERTAINLY NOT MUCH. REGARDLESS...WITH THE VERY STRONG JET DYNAMICS AND FULLY LEAFED TREES WE HAVE BEEN GETTING A LOT OF TREE DAMAGE REPORTS. WE DID EXTEND SEVERE THUNDERSTORM WATCH INTO NORTHEAST MA THROUGH 10 PM WHERE BEST LOW LEVEL JET MOVES INTO OVER THE NEXT FEW HOURS. ALSO...THE REST OF THE REGION IS COVERED IN A WIND ADVISORY EXCEPT FOR THE SOUTH COAST. MANY LOCATIONS MAY REMAIN BELOW WIND ADVISORY CRITERIA...BUT GIVEN FULLY LEAFED TREES INCREASED RISK FOR DAMAGE WILL CONTINUE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... LARGE HIGH PRES BUILDS E ACROSS SNE BRINGING SUNNY SKIES AND SEASONABLY MILD TEMPS. COLUMN IS QUITE DRY SO EVEN CU WILL BE LIMITED. HIGH TEMPS WILL REACH MID/UPPER 60S...COOLER HIGHER TERRAIN. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * DRY AND SEASONABLE WEATHER LIKELY WED AND MOST OF THU * A BIT OF RAIN POSSIBLE AT TIMES THU NIGHT INTO EARLY NEXT WEEK * MAY END UP COMPLETELY DRY IF STORM STAYS SOUTH DETAILS... TUESDAY NIGHT... HIGH PRESSURE WILL BUILD ACROSS NORTHERN NEW ENGLAND AND RESULT IN A CHILLY NIGHT. LOW TEMPS WILL FALL MAINLY INTO THE 30S...TO THE MIDDLE 40S ACROSS MOST AREAS. WE MAY NEED TO CONSIDER FROST ADVISORIES FOR PORTIONS OF SOUTHWEST NH/NORTHWEST MA...IF WINDS ARE ABLE TO DECOUPLE WHICH REMAINS UNCERTAIN AT THIS POINT. WEDNESDAY AND THURSDAY... LARGE HIGH PRESSURE SHOULD KEEP OUR WEATHER DRY WEDNESDAY INTO MOST OF THURSDAY AFTERNOON. MODEL CROSS SECTIONS DO INDICATE THAT WE MAY SEE SOME HIGH CLOUDINESS MOVE IN FROM A LOW PRESSURE SYSTEM OVER THE MID ATLANTIC. THIS SHOULD ALSO RESULT IN ONSHORE FLOW KEEPING HIGH MAINLY IN THE 60S...ALTHOUGH A FEW LOWER 70S MAY BE POSSIBLE ACROSS THE INTERIOR. THURSDAY NIGHT THROUGH MONDAY... FORECAST CONFIDENCE REMAINS VERY LOW OVER THIS TIME PERIOD. HIGH PRESSURE WILL REMAIN LOCATED ACROSS THE CANADIAN MARITIMES WITH A LOW MEANDERING SOMEWHERE TO OUR SOUTH. DEPENDING ON HOW FAR NORTH THIS LOW PRESSURE SYSTEM GETS WILL DETERMINE IF WE END UP GETTING A PERIOD OR TWO OF RAIN. BIGGER THREAT FOR A SUSTAINED PERIOD OF WET WEATHER WILL BE TO OUR SOUTH...BUT CAN/T RULE OUT SOME RAIN IN OUR REGION WITH BEST CHANCE IN THE SOUTHERN ZONES. THE MODELS AND ENSEMBLES HAVE SHOWN DIFFERING SOLUTIONS AND VERY POOR RUN TO RUN CONSISTENCY. WILL GENERALLY RUN WITH 20 TO 30 POPS TO COVER THIS POTENTIAL...WITH THE HIGHER POPS IN OUR SOUTHERN ZONES. BEST CHANCE FOR A BIT OF RAIN MAY COME THU NIGHT INTO FRI THEN AGAIN LATER SUN INTO MON. ITS ALSO POSSIBLE ALL THE RAIN REMAINS TO OUR SOUTH OVER THIS TIME...JUST TOO UNCERTAIN TO SAY MUCH MORE AT THIS POINT. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...HIGH CONFIDENCE IN TRENDS LOWER CONFIDENCE IN TIMING. CONDITIONS HAVE TEMPORARILY IMPROVED TO MVFR/VFR AS WARM FRONT HAS LIFTED TO THE NORTH. INCREASING S WINDS WILL DEVELOP WITH GUSTS TO 35 KT POSSIBLE THROUGH THE REST OF THE AFTERNOON...ESPECIALLY AWAY FROM S COAST. EXPECT IFR TO REDEVELOP LATER THIS AFTERNOON AND EVENING AS LINE OF SHOWERS/TSTMS MOVE THROUGH. BRIEF HEAVY RAIN AND STRONG WINDS WILL LIKELY ACCOMPANY THIS LINE OF CONVECTION...ESPECIALLY CT VALLEY THEN GRADUALLY WEAKEN AS IT MOVES TO THE COASTAL PLAIN. IMPROVING CONDITIONS TO VFR FROM WEST TO EAST 03-08Z. VFR TUESDAY. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR EXPECTED WITH A BRIEF PERIOD OF IFR POSSIBLE THIS EVENING. BRIEF HEAVY RAIN POSSIBLE 23-03Z. WIND GUSTS TO 35 KT THROUGH 00Z. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR WITH A BRIEF PERIOD OF IFR POSSIBLE LATE AFTERNOON AND EARLY EVENING. BRIEF HEAVY RAIN 21-00Z. WIND GUSTS TO 35 KT POSSIBLE THIS AFTERNOON. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... TUE NIGHT THROUGH THURSDAY...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. THURSDAY NIGHT THROUGH SATURDAY...LOW CONFIDENCE. SOME MVFR TO EVEN IFR CONDITIONS ARE POSSIBLE AT TIMES IF A MID ATLANTIC LOW MAKES IT FAR ENOUGH NORTH ALLOWING FOR SOME RAIN. BEST CHANCE WOULD BE THU NIGHT/FRI. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/...MODERATE CONFIDENCE. 520 PM UPDATE... ONLY CHANGE WAS TO UPGRADE BOSTON HARBOR TO A GALE WARNING THROUGH 9 PM WHERE AS BEST LOW LEVEL JET MOVES OVER THE REGION. TEMPS ARE ALSO THE WARMEST IN NORTHEAST MA...SO BETTER CHANCE OF MIXING TO THE GROUND. PREVIOUS DISCUSSION: LOW PROB FOR BRIEF SOUTHERLY GALES OVER EASTERN WATERS THROUGH EARLY EVENING AS THE LOW LEVEL JET PEAKS ACROSS THE WATERS. BUT LOW LEVEL INVERSION WILL LIMIT STRONGEST WINDS FROM MIXING DOWN SO IT IS MORE LIKELY THAT GUSTS WILL REMAIN IN SCA RANGE. BEST CHANCE FOR MARGINAL GALES MAY ACTUALLY OCCUR IN BOS HARBOR THROUGH 9 PM. WINDS SHIFT TO NW AND DIMINISH OVERNIGHT WITH SUBSIDING SEAS. NORTHERLY WINDS BELOW SCA TUESDAY. SEAS MOSTLY BELOW SCA AS WELL BUT 5 FT SEAS MAY LINGER OVER OUTER SE WATERS. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... HIGH CONFIDENCE IN OVERALL WIND DIRECTION....BUT LOWER CONFIDENCE IN WIND SPEEDS AND TIMING. LOW PRESSURE TO THE SOUTH OF OUR WATERS WITH HIGH PRESSURE OVER THE CANADIAN MARITIMES WILL RESULT IN A PERSISTENT EAST TO NORTHEAST FLOW OF AIR MOST OF THE TIME. PERIODS OF 20 TO 25 KNOT NORTHEAST WIND GUSTS ARE EXPECTED FOR MUCH OF THE PERIOD. WINDS MAY END UP A BIT STRONGER FOR A TIME...DEPENDING ON HOW FAR NORTH MID ATLANTIC LOW PRESSURE SYSTEM MAKES IT. IT DOES APPEAR THAT THE BEST CHANCE FOR THE STRONGER WINDS WILL BE ACROSS OUR SOUTHERN ATLANTIC WATERS. SCA SEAS ARE ALSO LIKELY FOR MUCH OF THE TIME ACROSS OUR SOUTHERN AND SOUTHEAST ATLANTIC WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ002>004. MA...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ002>019-026. NH...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NHZ011-012-015. RI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR RIZ001>004. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR ANZ231>235-237- 254>256. GALE WARNING UNTIL 10 PM EDT THIS EVENING FOR ANZ230-250-251. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ236. && $$ SYNOPSIS...KJC/FRANK NEAR TERM...FRANK SHORT TERM...KJC LONG TERM...FRANK AVIATION...KJC/FRANK MARINE...KJC/FRANK
AREA FORECAST DISCUSSION
NWS ALBANY NY
249 PM EDT MON OCT 7 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL BRIEFLY BE OVER THE REGION THIS AFTERNOON. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH HEAVY RAIN SHOWERS...GUSTY WINDS AND POSSIBLE STRONG TO SEVERE THUNDERSTORMS. BY TUESDAY...A DRIER...COOLER AND LESS HUMID AIR MASS WILL RETURN FOR MUCH OF THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 248 PM EDT... TORNADO WATCH 543 REMAINS IN EFFECT UNTIL 5 PM EDT FOR ERN NY AND NOW INCLUDES ALL OF WESTERN NEW ENGLAND. IT HAS BEEN EXPANDED TO INCLUDE SRN VT...WRN MA...AND NW CT. THE WIND ADVISORY REMAINS UP UNTIL 8 PM FOR ALL OF ERN NY AND WRN NEW ENGLAND. A COLD FRONT CONTINUES TO MOVE ACROSS ERN NY TOWARDS THE HUDSON RIVER VALLEY. A HIGH SHEAR AND LOW CAPE ENVIRONMENT IS IN PLACE ACROSS THE ALY FCST AREA WITH THE LATEST SPC MESO PAGE SHOWING INSTABILITY VALUES LESS THAN 500 J/KG ACROSS MOST OF THE AREA...WITH THE HIGHEST AMOUNTS ACROSS THE EXTREME SRN TIER. THE 0-6 KM BULK SHEAR VALUES HAVE INCREASED TO 40-65 KTS...WITH THE LOW-LEVEL 0-1 KM SHEAR VALUES ALSO VERY IMPRESSIVE IN THE 30-45 KT RANGE...WITH THE HIGHEST VALUES OVER THE NRN TIER. THE WIND ADVISORY LOOKS GOOD...AND SOME BOWING SEGMENTS WITH THE LINE ECHO WAVE PATTERN /LEWP/ UPSTREAM HAVE PRODUCED SOME ISOLD/SPORADIC WIND DAMAGE UPSTREAM OVER W-CNTRL NY AND PA. THE UPPER TROUGH IS TURNING NEGATIVELY TILTED...AND THERE IS A THREAT FOR SOME OF THIS STRONG MOMENTUM TRANSFERRED DOWN FROM H925-H850. THE PAUCITY OF INSTABILITY AND WEAK MID LEVEL LAPSE RATES HAVE INHIBITED CG STRIKES. THERE IS A STRIKE HERE OR THERE UPSTREAM. DUE TO THE DYNAMICALLY FORCED LEWP... THE POTENTIAL FOR SOME NEAR THUNDERLESS OR THUNDERLESS SEVERE STORMS WILL CONTINUE UNTIL LATE THIS PM. THE IMPACT PERIOD CONTINUES TO BE 1-5 PM FROM WEST TO EAST. THE LATEST 3-KM HRRR LINES UP WELL WITH THIS TIME FRAME. A BRIEF SPIN-UP TORNADO MAY BE POSSIBLE ALONG THE LEWP DUE TO THE STRONG LOW-LEVEL WIND SHEAR...DESPITE THE WEAK INSTABILITY. A TOR WARNING WAS ISSUED FOR PARTS OF HERKIMER...NW FULTON...AND SW HAMILTON COUNTY. SOME REPORTS OF WIND DAMAGE ARE COMING IN NEAR STRATFORD IN NW FULTON COUNTY. SEVERAL SVRS ARE BEING ISSUED FOR THE ALY FCST AREA AT THIS TIME. THE NARROW COLD FRONTAL RAIN BAND /SHALLOW LINE OF CONVECTION/ SHOULD BE EAST OF THE FCST AREA BY 6 PM. DESPITE THE CLOUD COVER...THE FCST AREA IN THE WARM SECTOR...HAS ALLOWED TEMPS TO REACH THE MID 60S TO M70S OVER THE REGION. TEMP FALLS IN THE WAKE OF THE COLD FRONT HAVE BEEN AS GREAT AS 15 DEGREES IN AN HOUR AT KSYR. A 46 KT GUST OCCURRED ABOUT 3 HOURS AGO. THE SHOWERS AND EMBEDDED TSTMS WILL LIKELY PRODUCE A PERIOD OF VERY HEAVY RAINFALL...FOR GENERALLY LESS THAN 2 HOURS. THE SHOWERS SHOULD GRADUALLY TAPER FROM W TO E AROUND OR JUST AFTER SUNSET. RAINFALL RATES COULD REACH A HALF AN INCH TO AN INCH AN HOUR DUE TO THE ANOMALOUS PWATS IN PLACE...AND THE STRONG CONVERGENCE WITH THE BOUNDARY. POPS...WX...AND TEMPS HAVE BEEN RETOOLED BASED ON THE OBSERVATIONAL TRENDS IN THE FCST GRIDS AND THE TOR WATCH EXPANSION. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... TONIGHT...ANY SHOWERS ACROSS EXTREME S/E AREAS SHOULD END BY 10 PM EDT. ADDITIONAL ISOLATED/SCATTERED SHOWERS COULD AFFECT THE WESTERN ADIRONDACKS LATER THIS EVENING OR OVERNIGHT...AS THE UPPER LEVEL COLD POOL PASSES ACROSS. OTHERWISE...EXPECT A PERIOD OF CLEARING IN MOST AREAS THIS EVENING...BUT ADDITIONAL CLOUDS MAY FORM ONCE AGAIN LATER TONIGHT AS THE COLD POOL PASSES BY...AND SOME LAKE MOISTURE SPREADS INTO THE REGION...ESP FOR AREAS NEAR AND N OF INTERSTATE 90. HAVE SIDED WITH THE SLIGHTLY WARMER MET MOS IN MOST AREAS. TUE-WED NT...GENERALLY DRY CONDITIONS ARE EXPECTED THROUGH THIS PERIOD. THE ONE CAVEAT COULD BE LINGERING CLOUDS ACROSS NORTHERN PORTIONS OF THE REGION TUESDAY...AS SOME LAKE MOISTURE BECOMES TRAPPED BENEATH A RAPIDLY LOWERING SUBSIDENCE INVERSION. FOR NOW HAVE INDICATED PARTLY TO MOSTLY SUNNY SKIES...BUT TRENDS WILL NEED TO BE WATCHED...AS MUCH MORE CLOUD COVER THAN CURRENTLY FORECAST COULD OCCUR FOR AREAS NORTH OF I-90. OTHERWISE...FOR TEMPS...GENERALLY SIDED WITH THE COOLER MET MPS FOR TUE MAXES...AND WENT A BIT WARMER THAN GUIDANCE FOR TUE NT MINS. SOME FROST POTENTIAL WILL EXIST IN PORTIONS OF THE UPPER HUDSON VALLEY...EASTERN CATSKILLS AND SOUTHERN VT...WHICH WILL BE ADDRESSED IN THE HWOALY. SOME HIGH AND MID LEVEL CLOUDS COULD SLOWLY EXPAND NORTH AND WEST INTO THE REGION LATE WED OR WED NT...DEPENDING ON THE TRACK AND EVOLUTION OF A POSSIBLE LOW PRESSURE SYSTEM DEVELOPING OFF THE SOUTHEAST COAST. && .LONG TERM /THURSDAY THROUGH MONDAY/... COMPLEX UPPER PATTERN SHOULD RESULT IN HIGHER UNCERTAINTY WITH DETAILS IN THE LONG RANGE FORECAST. IN THE THURSDAY THROUGH FRIDAY TIME FRAME...THERE IS A LOOSE CONSENSUS OF A COASTAL SYSTEM THAT DEVELOPS OFF THE MID ATLANTIC AS UPPER RIDGING BUILDS NORTH AND EAST INTO SOUTHEASTERN CANADA. MOST AREAS SHOULD BE UNDER THE INFLUENCE OF HIGH PRESSURE THURSDAY AND FRIDAY. EXCEPT...THERE COULD BE SOME CLOUDS AND ISOLATED SHOWERS IN THE SOUTHERN PARTS OF THE MID HUDSON VALLEY AND NW CT...WHERE THERE COULD BE SOME ONSHORE FLOW DUE TO THE PRESSURE GRADIENT DEVELOPING BETWEEN THE LOW LEVEL RIDGING OVER THE NORTHEASTERN U.S. AND THE COASTAL SYSTEM OFF THE MID ATLANTIC. HIGHS THURSDAY AND FRIDAY IN THE 60S TO NEAR 70. THE UPPER PATTERN POTENTIALLY BECOMES EVEN MORE COMPLICATED AS LOW LEVEL RIDGING BUILDS AND STRENGTHENS OVER SOUTHEASTERN CANADA AND EASTERN NEW ENGLAND AND THEN BUILDS WEST INTO NY SATURDAY AND SUNDAY. COOLER AIR ALSO BUILDS WEST INTO NY...POTENTIALLY RESULTING IN A COOLING TREND BOTH DAYS. THE UPPER RIDGING INTO SOUTHEASTERN CANADA MAY SUPPORT A SLIGHT NORTHWARD DRIFT TO THE UPPER FEATURE ASSOCIATED WITH THE LOW PRESSURE OFF THE EAST COAST...WITH MORE OF A PRESSURE GRADIENT AND ONSHORE FLOW IN SOUTHERN NY AND NW CT... DEPENDING ON EXACTLY HOW FAR NORTH THE COASTAL FEATURE CAN GET. WITH SUCH EXTREME SPREAD IN THE LONG RANGE GUIDANCE...GOING DRY FOR THE WEEKEND WITH HIGHS IN THE 60S...BUT COOLING A DEGREE OR TWO EACH DAY WITH THE COLD ADVECTION FROM THE EAST. MORE DETAILS WITH THIS COMPLICATED PATTERN SHOULD BE APPARENT TOWARD THE END OF THE WEEK...BUT AT LEAST THE RANGE OF POSSIBLE SENSIBLE WEATHER DOES NOT INCLUDE ANY HIGH IMPACT OR THREATENING WEATHER FOR OUR FORECAST AREA IN THE LONG RANGE...BUT SOME INCLEMENT WEATHER IS POSSIBLE DEPENDING ON HOW/IF THE COASTAL SYSTEM EVOLVES. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... COLD FRONT MAKING STEADY PROGRESS ACRS NYS AND EXPECT THE FRONT TO MOVE THROUGH THE TAF SITES IN THE 19Z-21Z TIME FRAME. GENERALLY EXPECT MVFR/IFR JUST AHEAD OF AND BEHIND THE FRONT WITH GUSTY WINDS AS WIND DIRECTION SHIFTS FROM S-SE AHEAD OF THE FRONT TO WESTERLY BEHIND THE FRONT. WIND GUSTS MAY BE AS HIGH AS 35 KTS WITH FROPA. ONCE FROPA HAS TAKEN PLACE EXPECT A FEW HOURS OF MVFR CONDITIONS WHICH WILL GIVE WAY TO VFR THIS EVENING. OVERNIGHT SKIES WILL BECOME SKC WELL AFTER MIDNIGHT AND FOG IS EPXECTED TO DEVELOP AT KGFL AND KPSF REDUCING CIGS AND VSBYS TO LIFR LATE AT NIGHT. ON TUESDAY EXPECT SKC CONDITIONS WITH NORTH TO NORTHWEST WINDS OF 8-10 KTS. OUTLOOK... LATE TONIGHT-FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE ANTICIPATED OVER THE NEXT FEW DAYS. AFTER A WETTING DAY ON SUNDAY...ANOTHER WETTING DAY WITH MORE RAIN SHOWERS AND SCATTERED THUNDERSTORMS ARE LIKELY THIS AFTERNOON AND EVENING. DRY WEATHER WILL RETURN TUESDAY THROUGH THE REMAINDER OF THE WEEK...WITH FULL RH RECOVERY EXPECTED EACH NIGHT WITH WIDESPREAD DEW FORMATION. && .HYDROLOGY... NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS FOR EARLY OCTOBER. A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND EVENING. MAINLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED THROUGH THIS MORNING WITH LIGHT PCPN AMOUNTS OF A TENTH OF AN INCH OR LESS. MUCH HEAVIER RAINFALL IS EXPECTED WITH THE COLD FRONT THIS AFTERNOON AND EVENING WITH THE POTENTIAL 0.75-1.5 INCH BASIN RAINFALL AVERAGES. ALL THE MODELS ARE NOW SHOWING THE COLD FRONT MOVING THROUGH QUICKLY...SO THERE APPEARS TO BE LITTLE IF ANY CHANCE THAT THE FRONTAL BOUNDARY AND THE HEAVY RAIN LINGERING OVER THE REGION AND PRODUCING MORE THAN TWO INCHES OF RAIN. DUE TO RECENT DRY CONDITIONS...FFG IS QUITE HIGH...AND THE COLD FRONT WILL BE MOVING FAST ENOUGH TO KEEP ANY HEAVY RAINFALL LIMITED TO JUST A FEW HOUR PERIOD. AS A RESULT...NO HYDROLOGIC PROBLEMS ARE ANTICIPATED OUTSIDE OF LOW LYING...POOR DRAINAGE...OR URBAN AREAS THAT TYPICALLY SEE WATER POND DURING HEAVY DOWNPOURS. DRY WEATHER WILL BE IN PLACE FOR TUESDAY THROUGH THE REMAINDER OF THE 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...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013. NY...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025. VT...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015. && $$ SYNOPSIS...KL/WASULA NEAR TERM...WASULA SHORT TERM...KL LONG TERM...NAS AVIATION...11/NAS FIRE WEATHER...KL/GJM HYDROLOGY...KL/GJM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
151 PM EDT MON OCT 7 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS ARE EXPECTED TODAY ALONG WITH GUSTY SOUTHERLY WINDS. A BAND OF HEAVY SHOWERS...STRONG WINDS AND PERHAPS ISOLATED THUNDERSTORMS ARE EXPECTED LATE THIS AFTERNOON AND EVENING WITH A STRONG COLD FRONT. HIGH PRESSURE AND DRY SEASONABLE WEATHER OVERSPREADS SOUTHERN NEW ENGLAND TUE AND WED. A COASTAL LOW MAY BRING ANOTHER ROUND OF RAIN TO THE REGION LATER THIS WEEKEND AND POSSIBLY INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ** GUSTY WINDS AND HEAVY RAINFALL WITH A COLD FRONT LATE TODAY ** 145 PM UPDATE... QLCS ALONG THE COLD FRONT APPROACHING E NY AND NW NJ. CONVECTION HAS INTENSIFIED A BIT WITH LEWP STRUCTURE DEVELOPING WHICH IS A GOOD INDICATOR OF STRONG WINDS. MESOANALYSIS INDICATING SBCAPES OF 500 J/KG AHEAD OF THE LINE IN SNE. HRRR IS HANDLING THIS FAIRLY WELL AND BRINGS LINE INTO THE BERKSHIRES AND CT VALLEY 21-22Z THEN WEAKENS IT AS IT APPROACHES THE COASTAL PLAIN THIS EVENING. GREATEST THREAT FOR SEVERE WX WILL BE ACROSS W ZONES...PARTICULARLY THE BERKSHIRES AND CT VALLEY. 0-1KM SR HELICITY 300-400 M2/S2 ALONG AND JUST AHEAD OF THE LINE SO THE THREAT OF AN ISOLD TORNADO CANT BE RULED OUT...ESPECIALLY IF WE CAN GENERATE 500-1000 J/KG OF SFC BASED CAPE. PREVIOUS DISCUSSION... WARM FRONT STILL HUNG UP ACROSS THE INTERIOR FROM NEAR HFD TO OWD. TEMPS HAVE RISEN INTO THE UPPER 60S TO LOWER 70S WITH DEWPOINTS UPPER 60S S OF THE FRONT BUT TEMPS ARE STILL MOSTLY IN THE 50S TO THE NORTH IN THE INTERIOR. WE EXPECT THE FRONT WILL EVENTUALLY JUMP TO THE N AS THE LOW LEVEL INVERSION EVENTUALLY MIXES OUT WITH TEMPS INCREASING RAPIDLY INTO THE 70S THIS AFTERNOON IN THE INTERIOR. THE WARM TEMPS WILL HELP TO INCREASE MIXING IN THE LOW LEVELS. WITH DECENT LOW LEVEL JET ACROSS THE REGION...EXPECT INCREASING WINDS THIS AFTERNOON WITH SOUNDINGS SUPPORTING GUSTS TO 35-40 KT. EVEN IF THE WIND GUSTS FALL JUST SHORT OF ADVISORY CRITERIA...THE FULLY LEAVED TREES WILL ENHANCE THE POTENTIAL FOR MINOR WIND DAMAGE. AS A RESULT WE EXPANDED THE WIND ADVISORY FOR ALL SNE EXCEPT THE IMMEDIATE S COAST WHERE MIXING WILL BE MORE SHALLOW. THERE ARE A FEW SHOWERS LIFTING N ACROSS SNE BUT MOST OF THE AREA IS DRY. THROUGH MID AFTERNOON...WE ARE JUST EXPECTING A FEW SHOWERS FROM TIME TO TIME WITH MOSTLY DRY WEATHER AS MAIN ACTION WILL BE TIED TO THE COLD FRONT LATE AFTERNOON AND EVENING. LINE OF CONVECTION ALREADY DEVELOPING ALONG THE COLD FRONT ACROSS CENTRAL NY AND PA AND HIRES MODELS SHOW A STRONG SIGNAL FOR A FINE LINE OF CONVECTION ALONG THE FRONT MOVING INTO THE BERKSHIRES AND CT VALLEY LATER TODAY. RIGHT ENTRANCE REGION OF UPPER LEVEL JET WILL ENHANCE FORCING FOR ASCENT AND COMBINED WITH LOW LEVEL JET EXPECT THE FRONTAL BAND OF CONVECTION TO INTENSIFY AS IT MOVES EAST. WE HAVE A STRONGLY SHEARED ENVIRONMENT LATER TODAY WITH 0-6KM SHEAR 50-60 KT. INSTABILITY WILL BE THE LIMITING FACTOR BUT WITH TEMPS RISING THROUGH THE 70S IT LOOKS LIKE SBCAPES WILL WILL REACH 500 J/KG WITH LOW PROB OF CAPES APPROACHING 1000 J/KG. GIVEN HIGHLY SHEARED ENVIRONMENT THIS INSTABILITY ENOUGH TO SUPPORT A FEW STRONG TO SEVERE TSTMS WITH DAMAGING WINDS WITH THIS FINE LINE LATER TODAY. IN ADDITION...0-1 KM SHEAR 40-45 KT AND 0-1KM HELICITY 300-400 M2/S2 WHICH IS VERY IMPRESSIVE SO CANT RULE OUT AN ISOLD TORNADO IN THIS ENVIRONMENT. THE TIMING OF THE FRONT IS 21-00Z ACROSS W ZONES. BRIEF HEAVY RAINFALL WILL BE A SECONDARY THREAT...BUT PROGRESSIVE NATURE OF THIS FRONT WILL LIMIT DURATION OF THE HEAVIEST RAINFALL TO AN HOUR OR 2 WHICH WILL LIMIT FLOOD POTENTIAL. STILL...THE HEAVY DOWNPOURS COULD LEAD TO AREAS OF URBAN AND POOR DRAINAGE FLOODING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... TONIGHT... THE LLJ AND COLD FRONT ARE EXPECTED TO LIFT AND LOSE A LITTLE OF ITS PUNCH AS IT MOVES E...HOWEVER THE THREATS MENTIONED ABOVE REMAIN UNTIL IT MOVES OFFSHORE BETWEEN AROUND 04Z. AFTERWARD...ASIDE FROM NW WINDS GUSTING SOMEWHAT /ALTHOUGH NOT NEARLY AS STRONG AS THE SOUTHERLY WINDS AHEAD AND ASSOCIATED WITH THE FRONT/ CONDITIONS WILL RAPIDLY IMPROVE...WITH SOME CLEARING EXPECTED ALMOST TO THE E COAST BY DAYBREAK. TEMPERATURES WILL RAPIDLY DECLINE S WELL. DIPPING INTO THE 40S IN NW MA AND SRN NH. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGHLIGHTS... * DRY AND SEASONABLE WEATHER TUE/WED * CHANCE OF RAIN LATE WEEK INTO NEXT WEEKEND SYNOPTIC OVERVIEW... NORTHERN STREAM TROUGH OVER THE ST. LWRNC RVR VLY EXITS NORTHEAST INTO THE MARITIMES TUE. MEANWHILE ITS ATTENDING COLD FRONT MOVES OFFSHORE WITH POST FRONTAL AIRMASS OVERSPREADING SOUTHERN NEW ENGLAND. BY WED DEEP LAYER RIDGE BUILDS OVER THE NORTHEAST AND IS ACCOMPANIED BY 1030MB SURFACE HIGH. THEN FORECAST UNCERTAINTY /ESPECIALLY TIMING/ INCREASE BY LATE IN THE WEEK AS LEFTOVER JET ENERGY FROM TODAY/S EASTERN TROUGH FORMS A WEAK MID LEVEL LOW OVER THE SOUTHEAST STATES. THIS STRENGTHENS ATTENDING SURFACE CIRCULATION AS IT TRAVERSES NORTHWARD TO THE MID ATLC COAST BY LATE IN THE WEEK. UPPER FLOW THEN BECOMES STAGNANT AS REX TYPE BLOCK DEVELOPS WITH RIDGE /POSSIBLY CLOSED ANTICYCLONE/ OVER NEW ENGLAND AND SOUTHEAST CANADA...ACCOMPANIED BY A CLOSED LOW OVER MID ATLC REGION OR JUST OFFSHORE. MODEL PREFERENCES... GOOD MODEL AGREEMENT TUE AND WED WITH RIDGING DEVELOPING OVER THE NORTHEAST. THEN MODEL SPREAD EVOLVES THU/FRI AND INTO NEXT WEEKEND. THE 00Z GFS AND ITS ENSEMBLES /GEFS/ ARE ON THE FAST AND PROGRESSIVE SIDE OF THE GUID ENVELOPE...BRINGING A COASTAL LOW WITH REMNANTS OF KAREN NORTHWARD AND POSSIBLY IMPACTING SOUTHERN NEW ENGLAND WITH A PERIOD OF RAIN AND WIND THU/FRI. THE 00Z EC IS MUCH SLOWER AND LESS PROGRESSIVE WITH RAIN AND WIND HOLDING OFF UNTIL FRI OR SAT... HOWEVER THEN POSSIBLY LINGERING PRECIP INTO SUN. THE GFS IS STRONGER/MORE AMPLIFIED WITH THE NORTHERN STREAM AND AS A RESULT THE COASTAL LOW IS KICKED SEAWARD SAT...SUPPORTING A DRYING TREND FOR NEXT WEEKEND. THE GFS MAY BE CLOSER TO CONSENSUS GIVEN ITS ENSEMBLE MEAN AND THE 00Z UKMET SUPPORT THIS PROGRESSIVE SOLUTION. ALTHOUGH GIVEN THE TIME RANGE HERE AND MODEL SPREAD THINK LOW CHANCE AND SLIGHT CHANCE POPS BETTER REFLECT THIS UNCERTAINTY...WITH HIGHEST POPS ALONG THE SOUTH COAST. IN ADDITION...DID NOT FOLLOW LIKELY POPS FROM GMOS THU INTO FRI FOR THE SAME REASON. INSTEAD STAYED CLOSE TO THE MORE CONSERVATIVE HPC GUID POPS THURSDAY THROUGH SUNDAY. SENSIBLE WEATHER... TUE AND WED...DRY AND SEASONABLY COOL. MILDER TUE AS CORE OF COOLER AIR SETTLES OVER THE REGION WED. LIGHTER WINDS WED AS 1032 MB HIGH CREST ACROSS THE AREA. THE EXCEPTION WILL BE OVER CAPE COD AND THE ISLANDS WHERE PGRADIENT WILL GET SQUEEZED A BIT YIELDING AT LEAST A MODEST NE WIND THERE. THURSDAY THROUGH SUNDAY...AS MENTIONED ABOVE LOTS OF UNCERTAINTY HERE WITH POTENTIAL COASTAL STORM. MODEL CONSENSUS WOULD SUGGEST A PERIOD OF WIND AND RAIN LATE THU INTO FRI...THEN POSSIBLY IMPROVING/DRYING TREND OVER THE WEEKEND. ALTHOUGH WE WILL GO WITH LOW CHANCE/SLIGHT CHANCE POPS TO REFLECT SOME UNCERTAINTY ON RAIN CHANCES. TEMPS NEAR NORMAL BUT PERHAPS BELOW NORMAL IF RAIN MOVES ONSHORE ESPECIALLY WITH ANY DURATION. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...HIGH CONFIDENCE IN TRENDS LOWER CONFIDENCE IN TIMING. CONDITIONS HAVE TEMPORARILY IMPROVED TO MVFR/VFR AS WARM FRONT HAS LIFTED TO THE NORTH. INCREASING S WINDS WILL DEVELOP WITH GUSTS TO 35 KT POSSIBLE THROUGH THE REST OF THE AFTERNOON...EXPECIALLY AWAY FROM S COAST. EXPECT IFR TO REDEVELOP LATER THIS AFTERNOON AND EVENING AS LINE OF SHOWERS/TSTMS MOVE THROUGH. BRIEF HEAVY RAIN AND STRONG WINDS WILL LIKELY ACCOMPANY THIS LINE OF CONVECTION...ESPECIALLY CT VALLEY THEN GRADUALLY WEAKEN AS IT MOVES TO THE COASTAL PLAIN. IMPROVING CONDIITONS TO VFR FROM WEST TO EAST 03-08Z. VFR TUESDAY. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR EXPECTED WITH A BRIEF PERIOD OF IFR POSSIBLE THIS EVENING. BRIEF HEAVY RAIN POSSIBLE 23-03Z. WIND GUSTS TO 35 KT THROUGH 00Z. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. WIDESPREAD MVFR WITH A BRIEF PERIOD OF IFR POSSIBLE LATE AFTERNOON AND EARLY EVENING. BRIEF HEAVY RAIN 21-00Z. WIND GUSTS TO 35 KT POSSIBLE THIS AFTERNOON. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUE NIGHT/WED...VFR-DRY WEATHER WITH LIGHT WINDS...EXCEPT MODEST NE WINDS CAPE COD AND THE ISLANDS. FORECAST CONFIDENCE HIGH. THU/FRI...MVFR-IFR POSSIBLE IN PERIODS OF RAIN AS A COASTAL LOW MOVES UP THE EASTERN SEABOARD. GUSTY NE WINDS POSSIBLE. FORECAST CONFIDENCE LOW. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. SOUTHERLY WINDS WILL CONTINUE TO INCREASE THROUGH THE DAY...LEADING TO SMALL CRAFT ADVISORY CONDITIONS OVER ALL THE WATERS SAVE FOR THE NRN WATERS AND WATERS IMMEDIATELY ADJACENT TO THE NORTHERN SHORELINES...WHERE SOME GUSTS TO GALE FORCE ARE POSSIBLE. GIVEN THIS...HAVE ISSUED A GALE WARNING FOR THE NORTHERN WATERS /SAVE FOR BOSTON HARBOR/ WITH SMALL CRAFT ADVISORIES ELSEWHERE. WINDS WILL RAPIDLY SHIFT TO THE NW TONIGHT BEHIND A COLD FRONT /WHICH MAY DELIVER SHORT LIVED GALE FORCE GUSTS ON ALL WATERS/ BUT THE SMALL CRAFT ADVISORY CONDITIONS REMAIN INTO TUE MORNING. OUTLOOK...TUESDAY THROUGH FRIDAY... TUE/WED...HIGH PRES MOVES ACROSS NORTHERN NEW ENGLAND. LIGHT WINDS EXCEPT GUSTY NE WINDS SOUTHERN NEW ENGLAND WATERS. HIGH FORECAST CONFIDENCE. THU/FRI...A COASTAL STORM WILL LIKELY MOVE UP THE EASTERN SEABOARD. UNCERTAIN HOW FAR NORTH AND DURATION. HIGHEST RISK OF STRONG WINDS/LARGE SEAS AND HEAVY RAIN WILL BE SOUTH OF NEW ENGLAND. LOW FORECAST CONFIDENCE. && .HYDROLOGY... THE THREAT FOR CONVECTION AND HIGH PWAT AIRMASS WILL COMBINE TO YIELD A RISK FOR URBAN AND POOR DRAINAGE...AND POSSIBLY EVEN SMALL STREAM FLOODING AT TYPICALLY FLASHY STREAMS LATE TODAY INTO THE EARLY OVERNIGHT HOURS. THE STRONGEST LLJ AND HIGHEST MOISTURE CONTENT WILL BE IN THE WEST...ESPECIALLY WEST OF A WILLIMANTIC- WORCESTER-MANCHESTER LINE. THERE IS THE POTENTIAL FOR WIDESPREAD 1.0+ INCHES THERE...BUT LOCALLY HIGHER AMOUNTS APPROACHING 2.0 INCHES ARE POSSIBLE WITH ANY STORMS/HEAVY SHOWERS. EAST OF THE LINE...WIDESPREAD RAINFALL OF 0.5-1.0 INCHES ARE POSSIBLE AS THE LLJ WEAKENS AND DRIER AIR BUILDS IN...BUT AGAIN LOCALIZED HEAVIER AMOUNTS ARE POSSIBLE. A PROLONGED DRY SPELL WILL HELP MITIGATE THE THREAT...BUT GIVEN THAT ANY SHOWER OR STORM COULD BE HEAVY...WILL NEED TO MONITOR RAINFALL RATES/TRENDS. FINALLY...ONE OTHER NOTE IS THAT WITH LEAVES BEGINNING TO FALL...SOME CLOGGED DRAINS MAY EXACERBATE NUISANCE FLOODING IN SOME LOCATIONS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ002>004. MA...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ003>007- 010>019-026. WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MAZ002-008-009. NH...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NHZ011-012-015. RI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR RIZ001>004. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR ANZ230>237-255- 256. GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR ANZ250-251-254. && $$ SYNOPSIS...NOCERA/DOODY NEAR TERM...KJC SHORT TERM...DOODY LONG TERM...NOCERA AVIATION...KJC/NOCERA MARINE...NOCERA/DOODY HYDROLOGY...
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1000 AM EDT Mon Oct 7 2013 .NEAR TERM [Rest of Today]... ---Updated at 10:00 AM EDT--- The remnant low formerly known as "Karen" was located about 30 miles or so south-southeast of St. George Island as of 13 UTC. The low will continue to slowly shift east today to near the mouth of the Suwannee River by late afternoon. A synoptic cold front was not situated far behind - roughly from Macon to Panama City - but there was a distinct gap between the remnant low and the cold front. Aloft, a subtle but potent upper level PV anomaly was moving east near the mouth of the Mississippi River. Linear extrapolation and the latest RAP runs push the upper level wave into the western part of our area closer to 00 UTC. The approach of stronger upper level forcing from the west yet to arrive, as diagnosed well by the previous shift, should be able to generate some surface response. Even some minor pressure falls would be sufficient to temporarily delay or stall the eastward motion of the cold front. The result will be a fairly deep deformation zone (900-500mb) over the area that will be very slow to pivot east today. This should help maintain sufficient forcing for continued cloud cover and showers through the day - particularly in the eastern half of our area, and especially when you consider the 2.04" PWAT on the morning sounding from our office (close to +2 std. deviations above normal, or about 175% of normal). Therefore, high PoPs and cloud cover were maintained over the eastern portions of our area. High temperatures were adjusted to fit closer to raw model guidance, and in particular the average of the last few runs of the HRRR. This yields upper 70s in most locations, although some spots that see more regular breaks of sun could reach 80-82 degrees. && .SHORT TERM [Tonight Through Wednesday]... As the primary upper trough lifts northeast into Canada tonight, a southern shortwave over the Gulf of Mexico will slide east and cutoff a weak upper low over north florida. This upper low will lift slowly northward into the central Appalachians through Wednesday. At the surface, the area of low pressure currently over the northeastern Gulf will move slowly across northeast tonight into Tuesday, before moving northeastward off the coast Tuesday night into Wednesday. High pressure, centered over New England will nose southward to the Gulf Coast behind the surface low. This evolution will prevent low-level dry air from pushing into much of the region over the next few days, keeping plenty of clouds in place. In addition, showers are expected to develop within the cool northeasterly flow in the wake of the surface low, aided by the upper level low. Thus, for Tuesday, have lowered high temperatures and raised PoPs, especially for southwest and south central Georgia. The support for rain should diminish into Wednesday. However, the low-level moisture will be slow to scour out, with low clouds and cooler temperatures lingering. && .LONG TERM [Wednesday Night through Sunday]... In general there is good model agreement for this period with quiet weather and temperatures near or slightly below climatology. Expect dry conditions with highs in the low to mid 80s and overnight lows in the mid 50s to mid 60s. && .AVIATION [through 12 UTC Tuesday]... ---Updated at 10:00 AM EDT--- A patch of IFR CIGS was persisting in portions of SE Alabama and the western Florida Panhandle as of 14 UTC, roughly centered on DHN. ECP was on the southern periphery. This could linger until around 17-18 UTC, when guidance suggests clouds will lift and scatter out. These TAFs will be amended to account for that cloud layer. Elsewhere, MVFR ceilings and periodic -SHRA will prevail at ABY, TLH, VLD. && .MARINE... ---Updated at 10:00 AM EDT--- The remnant low has shifted into the section of the coastal waters east of Apalachicola. Observations and the consensus of all models is that winds will be weaker immediately near the low, and be stronger on the back side of the low (and behind a nearby cold front). With this in mind, we will be converting the eastern waters to a SCEC headline for some patches of 15-20 knot winds today, and more widespread 15-20 knot winds tonight. The western waters will have a Small Craft Advisory through 06 UTC for the stronger north winds behind the low. && .FIRE WEATHER... Relative humidity values will remain above critical levels for the foreseeable future. Thus, hazardous fire weather conditions are not anticipated. && .HYDROLOGY... While localized heavy rain will be possible through this afternoon, primarily across the eastern half of the area, most areas will see less than an inch. This should have little impact on area rivers and streams. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 79 65 82 61 80 / 60 30 30 10 10 Panama City 79 64 82 64 81 / 30 10 10 10 10 Dothan 77 59 79 58 78 / 50 20 30 10 10 Albany 78 64 75 58 75 /100 30 40 20 10 Valdosta 80 66 78 59 75 / 70 40 50 20 10 Cross City 80 67 85 62 82 / 70 40 30 10 10 Apalachicola 82 67 80 65 80 / 60 10 20 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...SMALL CRAFT ADVISORY until 2 AM EDT Tuesday morning for coastal waters west of Apalachicola, out to 60 NM. && $$ NEAR TERM...Lamers SHORT TERM...Camp LONG TERM...Hollingsworth AVIATION...Lamers MARINE...Lamers FIRE WEATHER...Harrigan HYDROLOGY...Camp
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
430 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE AREA TODAY AND TONIGHT...STALLING OFF THE COAST AS COOLER HIGH PRESSURE BUILDS IN FROM THE WEST AND NORTH. AN AREA OF LOW PRESSURE...THE REMNANTS OF KAREN...WILL MOVE UP THE COAST ALONG THE STALLED FRONT TUESDAY AND WEDNESDAY. HIGH PRESSURE WILL GENERALLY PREVAIL THURSDAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... PRE-DAWN...A DEEP MOIST PLUME OFF THE ATLC AND STRONG LOW LEVEL MOISTURE CONVERGENCE CONTINUES TO IGNITE BATCHES OF SHOWERS FROM THE OCEAN...ONSHORE OVER SOUTHERN SOUTH CAROLINA AND THROUGH THE CHARLESTON QUAD-COUNTY. THERE IS 25 KT OF SHEAR IN THE 0-1KM LAYER AND A FEW SHOWERS HAVE PRODUCED SOME BRIEFLY GUSTY WINDS AND EVEN VERY WEAK ROTATION AT TIMES. LATEST RAP SHOWS CONTINUED DESTABILIZATION EARLY THIS MORNING AND INCREASING UPPER DIFLUENCE. WE WILL BE KEEPING AN EYE OUT FOR ISOLATED STRONG CELLS EMBEDDED WITHIN THE MAIN BAND OF CONVERGENCE. IF NOTHING ELSE...WITH PWATS NEAR 1.9 INCHES...BRIEF TORRENTIAL DOWNPOURS ARE LIKELY WITH ACTIVITY THAT STREAMS ONSHORE. THIS COULD SPELL LOCALIZED MINOR FLOODING ISSUES WITH SOME PONDING WATER IN SPOTS ACROSS PARTS OF CHARLESTON AND BERKELEY COUNTIES AT TIMES. AN EXTREMELY COMPLEX SYNOPTIC SCENE TODAY WITH A PLETHORA OF PLAYERS OF INTEREST. BANDS OF DEEP TROPICAL MOISTURE ADVECTING IN FROM BOTH THE ATLC AND THE GULF OF MEXICO...GULF MOISTURE RESIDUAL FROM REMNANTS OF KAREN. LIKELY TO CATEGORICAL POPS IN ORDER TODAY WITH GEORGIA AREAS THE MOST DIFFICULT TO PIN DOWN. IN SE GEORGIA...THE DEEP MOISTURE WILL ARRIVE DURING THE DAY BUT MAINLY MISSING OUT ON A GOOD BIT OF THE UPPER FORCING THIS MORNING THAT IS SHIFTING THROUGH THE CSRA-MIDLANDS-PEE REGIONS OF GA/SC. THIS AFTERNOON THAT REGION WILL BE BETWEEN MID LEVEL DISTURBANCES WITH MARGINAL INSTABILITY AND NOT MUCH LOW LEVEL CONVERGENCE. THE PWATS ARE SO ANONYMOUSLY HIGH HOWEVER...WE DID NOT DO TOO MUCH RE-ARRANGEMENT OF OUR POP SCHEME. IN SE SOUTH CAROLINA...CLOSER TO THE CHARLESTON AREA...IT LOOKS LIKE A WET AND UNSETTLED A DAY. DEEP LAYERED SHEAR GENERALLY DECREASES DURING THE DAY BIT THROUGH EARLY AFTERNOON...WE CANNOT RULE OUT AN ISOLATED STRONG TO SEVERE TSTM BUT MOISTURE PROFILES AND FORECAST SOUNDINGS SUGGEST THE 5 PERCENT RISK FROM THE STORM PREDICTION CENTER IS ON TRACK FOR THE FIRST HALF OF TODAY UNTIL THE LOW LEVEL JET PULLS OUT. CONVECTIVE ELEMENTS ALREADY HAVE PRODUCED TORRENTIAL DOWNPOURS EAST OF I-95 IN SOUTH CAROLINA AND SUSPECT THIS WILL REMAIN THE CASE AHEAD OF THE COLD FRONT TODAY. TONIGHT THE COLD FRONT BEGINS TO BACKDOOR S THROUGH THE REGION TONIGHT AS SURFACE HIGH PRES BUILDS INTO THE MID ATLC REGION WHILE LOW PRES SETTLES IN OVER N FLORIDA. GOOD UPPER FORCING FOR ASCENT IS PROGGED TO DEVELOP OVER THE REGION FROM S TO N OVERNIGHT AS THE BASE OF THE SOUTHERN LATITUDE TROUGH MOVES THROUGH S GEORGIA AND N FLORIDA. AN EXCELLENT SETUP FOR THE START OF SOME SOAKING RAINFALL AT TIMES WHICH WILL BE IN THE FORECAST INTO MID WEEK. WE RAISED LATE NIGHT POPS IN SE GEORGIA TO CATEGORICAL ON THIS PACKAGE. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... THE MODEL SUITE HAS CHANGED DRASTICALLY FROM WHAT WE WERE ANALYZING 24 HOURS PRIOR. A STRONGER THAN PREVIOUSLY EXPECTED SOUTHERN STREAM VORT IS TRACKING ALONG THE WESTERN GULF COAST. THIS FEATURE WILL INTERACT WITH THE RESIDUAL LOW FROM KAREN AS IT CROSSES FLORIDA. MEANWHILE A LARGE AREA OF HIGH PRESSURE WILL OVERSPREAD THE EASTERN UNITED STATES TUESDAY. AS THE REMNANT SURFACE LOW MOVES INTO THE SOUTHWEST ATLANTIC AHEAD OF THE UPPER VORT...IT WILL DEEPEN AS IT LIFTS SLOWLY NORTHEAST. A COLD AIR DAMMING REGIME WILL DEVELOP AND PERSIST FROM TUESDAY THROUGH THURSDAY AS THE OFFSHORE LOW STRENGTHENS COLD AIR ADVECTION ACROSS INLAND AREAS. CONDITIONS LOOK RIPE FOR WIDESPREAD PRECIPITATION ON TUESDAY...ESPECIALLY SOUTHERN SC. THE NAM SHOWS AN IMPRESSIVE COUPLED UPPER JET OVER THE REGION AT 18Z TUESDAY...PRODUCING STRONG UPPER DIVERGENCE. FAIRLY DEEP MOISTURE WILL STREAM IN OFF THE ATLANTIC ATOP THE COOL SURFACE WEDGE WITH PWATS AROUND 2 INCHES. STRONG LIFT WILL DEVELOP OVERHEAD TUESDAY...WITH THE BEST LIFT SHIFTING NORTHEAST OF THE AREA TUESDAY NIGHT. WE INCREASED POPS TO CATEGORICAL ACROSS SOUTHERN SC ON TUESDAY WITH LIKELY POPS ELSEWHERE AND THROUGH TUESDAY NIGHT. TEMPERATURES ON TUESDAY WILL BE A REAL SHOCK COMPARED TO TODAY. OVERCAST SKIES...STRONG COLD ADVECTION AND EXTENSIVE PRECIP WILL LIMIT HIGH TEMPS TO THE MID/UPPER 60S EXCEPT FOR A FEW 70S CLOSER TO THE COAST. THE SURFACE LOW WILL VERY SLOWLY LIFT NORTHEAST JUST OFF THE COAST WEDNESDAY AND WEDNESDAY NIGHT. THOUGH THE BEST LIFT WILL SHIFT NORTHEAST OF THE LOCAL FORECAST AREA...ENOUGH RESIDUAL MOISTURE AND OVERRUNNING WILL MAINTAIN OVERCAST SKIES AND SCATTERED RAIN SHOWERS ON WEDNESDAY. HIGH TEMPS WILL AGAIN BE WELL BELOW NORMAL DUE TO THE AFOREMENTIONED LIMITING FACTORS. WE ARE SHOWING UPPER 60S TO LOWER 70S. THE MOISTURE AND LIFT ASSOCIATED WITH THE COASTAL LOW WILL SHIFT NORTHEAST OF THE AREA ON THURSDAY AS THE UPPER LOW ALSO LIFTS NORTHEAST. CLOUDS WILL SLOWLY CLEAR OUT FROM THE SOUTHWEST AND RAIN CHANCES WILL BE MINIMAL. TEMPERATURES SHOULD MAKE IT INTO THE MIDDLE 70S BY AFTERNOON. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... BROAD HIGH PRESSURE WILL PREVAIL DURING THE EXTENDED WITH GENERALLY DRY WEATHER AND SEASONABLE TEMPERATURES IN THE 50S AT NIGHT AND 70S DURING THE DAY. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... KCHS...SHOWERS AND MVFR CIGS ARE EXPECTED TO IMPACT THE TERMINAL OCCASIONALLY THROUGH THE MORNING HOURS. SMALL CHANCES FOR IFR CONDITIONS...THEY LIKELY WOULD BE VERY BRIEF AND NO FOG CONCERNS. LOW CONFIDENCE ON TIMING CHANCES FOR RAIN LATER TODAY WITH A COMPLEX SYNOPTIC SETUP AND A SEEMINGLY EXCELLENT COMBO OF DEEP MOISTURE AND UPPER DYNAMICS. OUTSIDE OF SHOWER AREAS...WE ARE MOST LIKELY TO BE VFR THROUGH 06Z TUE. KSAV...LOW CONFIDENCE WITH REGARDS TO FORECASTING THE ELEMENTS THROUGH THIS EVENING GIVEN THE TERMINALS PROXIMITY TO SEVERAL DEEP MOISTURE SOURCES AND MODEL DISCREPANCIES WITH REGARD TO COVERAGE AND TIMING OF RAIN. WE MAINTAINED PERSISTENCE WITH THE PREVIOUS TAF INDICATING THE BEST CHANCES OF RAIN FROM LATE MORNING THROUGH MID AFTERNOON BUT IT COULD BE LATER OR LESS THAN PROJECTED. CIGS WILL MAINLY BE VFR OVERNIGHT BUT LATE NIGHT THROUGH MID MORNING THERE IS A CHANCE FOR MVFR/IFR CIGS TO STREAM THROUGH BUT NO FOG CONCERNS. EXTENDED AVIATION OUTLOOK...A PROLONGED PERIOD OF MVFR/IFR CEILINGS IS EXPECTED FROM LATE TONIGHT THROUGH THURSDAY NIGHT. PREVAILING MVFR CEILINGS LIKELY DURING DAYTIME HOURS WITH A DROP TO IFR EACH OVERNIGHT PERIOD. VSBYS MAY BE OCCASIONALLY REDUCED IN RAIN TUESDAY THROUGH WEDNESDAY. && .MARINE... A SSE FLOW 15 KT TO OCCASIONALLY 15-20 KT AT TIMES HAS RAISED SEAS TO 6 FT OUT AT BUOY 41004 BUT MAINLY 3 TO 5 FT WITHIN 20 NM OF THE COAST...HIGHEST OFF OF CHARLESTON COUNTY. THE LOW LEVEL JET AHEAD OF THE COLD FRONT WILL WEAKEN TODAY AS THE LOW LEVEL FRONTAL TROUGH APPROACHES. WINDS WILL BECOMES LIGHTER THIS AFTERNOON AND EVENING AND EVEN VARIABLE AT TIMES. SEAS WILL ALSO DIMINISH A BIT. LATER TONIGHT...CHANGES IN THE OFFING AS N TO NE SURGING BEGINS TO INCREASE TOWARD DAYBREAK TUESDAY IN THE WAKE OF THE COLD FRONT. THE LATE NIGHT SURGE WILL BE MOST NOTICEABLE OFF OF THE CENTRAL SOUTH CAROLINA COAST AND LIKELY REACH 15 KT BY DAWN. SEAS TONIGHT 2 TO 4 FT. WINDS WILL CRANK UP FROM THE NNE TUESDAY IN RESPONSE TO THE COASTAL LOW MOVING INTO THE SOUTHWEST ATLANTIC FROM THE GULF. THE GRADIENT WILL BECOME PINCHED BETWEEN INLAND HIGH PRESSURE AND COASTAL LOW PRESSURE...PRODUCING A PROLONGED STRETCH OF ENHANCED NNE WINDS. SMALL CRAFT ADVISORY CONDITIONS WILL LIKELY DEVELOP DURING THE DAY TUESDAY WITH MARGINAL ADVISORY CONDITIONS CONTINUING INTO WEDNESDAY OR LATER. SEAS WILL NOT BUILD SUBSTANTIALLY DUE TO THE OFFSHORE FETCH BUT SOME 6 FOOTERS ARE POSSIBLE AT TIMES MAINLY BEYOND 20 NM FROM SHORE. WINDS WILL CONTINUE OUT OF THE N/NNE INTO THE WEEKEND BUT SPEEDS WILL DROP OFF CONSIDERABLY BY THURSDAY AS THE SURFACE LOW LIFTS NORTHEAST AND THE GRADIENT WEAKENS. RIP CURRENTS...AFTER A COLD FRONT ADVANCES THROUGH THE REGION... SUSTAINED NNE WINDS COULD CONTRIBUTE TO AN ELEVATED RIP CURRENT RISK ON AREA BEACHES TUESDAY THROUGH THURSDAY. && .TIDES/COASTAL FLOODING... BEGINNING TUESDAY...ASTRONOMICAL HIGH TIDES COULD COMBINE WITH PERSISTENT/ELEVATED NORTHEAST WINDS TO PRODUCE MINOR SALTWATER INUNDATION IN LOW-LYING AREAS NEAR THE COAST AROUND THE TIMES OF THE LATE MORNING/EARLY AFTERNOON HIGH TIDES. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...JRL LONG TERM...JRL AVIATION... MARINE...JRL TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
145 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA MONDAY AND WILL PUSH THROUGH THE REGION MONDAY NIGHT INTO TUESDAY. AN UPPER LEVEL LOW PRESSURE IS THEN EXPECTED TO SLOWLY TRACK NORTHEAST OVER THE REGION THROUGH MIDWEEK. HIGH PRESSURE WILL EXPAND INTO THE REGION AND WILL PREVAIL THROUGH NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... A DEEP MOIST PLUME OFF THE ATLC AND STRONG LOW LEVEL MOISTURE CONVERGENCE CONTINUES TO IGNITE BATCHES OF SHOWERS FROM THE OCEAN...ONSHORE OVER SOUTHERN SOUTH CAROLINA AND THROUGH THE CHARLESTON QUAD-COUNTY. THERE IS ABOUT 20 KT OF SHEAR IN THE 0-1KM LAYER AND A FEW SHOWERS HAVE PRODUCED SOME BRIEFLY GUSTY WINDS AND EVEN VERY WEAK ROTATION OFFSHORE. LATEST RAP SHOWS CONTINUED DESTABILIZATION OVERNIGHT AND INCREASING UPPER DIFLUENCE. WILL BE KEEPING AN EYE OUT FOR ISOLATED STRONG CELLS EMBEDDED WITHIN THE MAIN BAND OF CONVERGENCE. IF NOTHING ELSE...WITH PWATS NEAR 1.9 INCHES...BRIEF TORRENTIAL DOWNPOURS ARE LIKELY WITH ACTIVITY THAT STREAMS ONSHORE. THIS COULD SPELL MINOR FLOODING ISSUES WITH SOME PONDING WATER IN SPOTS ACROSS PARTS OF CHARLESTON AND BERKELEY COUNTIES AT TIMES. WE LOWERED POPS A BIT IN THE OVERNIGHT TO THE W OF I-95 AS LATEST MODELS SHOW A VOID AREA BETWEEN THE CONVECTION OVER N GEORGIA AND THE SOUTH CAROLINA UPSTATE AND THE MASS OF CONVECTION ASSOCIATED WITH THE EX-TROPICAL LOW IN THE NE GULF OF MEXICO. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... AHEAD OF AN APPROACHING COLD FRONT...AN AXIS OF DEEP LAYER MOISTURE AND FORCING FOR ASCENT SUPPORTED IN PART BY UPPER JET DIVERGENCE WILL ALREADY BE ADVANCING IN TO THE FORECAST AREA MONDAY MORNING AND WILL GRADUALLY ADVANCE THROUGH THE REGION DURING THE DAY. THIS SCENARIO WILL SUPPORT MOST/ALL LOCATIONS SHOULD RECEIVE MEASURABLE RAINFALL. 12Z GUIDANCE CONTINUES TO JUSTIFY ONGOING CATEGORICAL POPS. PWATS AROUND 2 INCHES COULD SUPPORT LOCALLY HEAVY RAINFALL. ALSO...CANNOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM WITH DAMAGING WET MICROBURSTS. HOWEVER...CLOUD COVER/PRECIPITATION WILL LIMIT WARMING/DESTABILIZATION...AND THE AXIS OF STRONGEST WIND SHEAR WILL REMAIN WELL NORTH OF THE REGION...SO THE POTENTIAL FOR SEVERE WEATHER APPEARS QUITE LOW. BY MONDAY EVENING...THE AXIS OF DEEPEST MOISTURE WILL SHIFT INTO COASTAL COUNTIES AN/OR ADJACENT COASTAL WATERS...AND THE SURFACE COLD FRONT WILL PRESS THROUGH THE FORECAST AREA FROM NORTH TO SOUTH OVERNIGHT INTO TUESDAY MORNING. MEANWHILE...A SHORTWAVE TROUGH NOTED ON WATER VAPOR IMAGERY ADVANCING THROUGH EAST TX WILL DIG INTO THE NORTHERN GULF OF MEXICO THEN WILL SWING TOWARD THE SOUTHEAST COAST MONDAY NIGHT THROUGH TUESDAY. IN RESPONSE TO FORCING FOR ASCENT IN ADVANCE OF THIS FEATURE...THE POST FROPA DRYING TREND WILL CEASE AND DEEP LAYER MOISTURE WILL LIKELY EXPAND TOWARD THE N/W INTO THE FORECAST AREA. AS A RESULT...BUMPED MONDAY NIGHT POPS UP A BIT FROM THE PREVIOUS FORECAST...THEN RAISED POPS SIGNIFICANTLY ACROSS THE FORECAST AREA TUESDAY. AS OF THE SUNDAY AFTERNOON FORECAST PACKAGE...CAPPED MAX POPS AT HIGH CHANCE TUESDAY...BUT HIGHER POPS COULD EVENTUALLY BE REQUIRED. MEANWHILE...A WEDGE OF COOL/MOIST ARE WILL OVERSPREAD THE FORECAST AREA TUESDAY...AND TEMPERATURES WILL LIKELY NOT RECOVER BEYOND THE LOWER TO MID 70S MOST AREAS. IN FACT...IF/WHERE PRECIPITATION BECOMES MORE WIDESPREAD THAN CURRENTLY FORECAST...TEMPERATURES COULD REMAIN IN THE 60S ACROSS SOME N/W COUNTIES. THE UPPER LOW IS PROGGED TO ONLY SLOWLY ROLL NE ALONG THE SE COAST TUESDAY NIGHT THROUGH WEDNESDAY...THUS AT LEAST SLIGHT CHANCE/CHANCE POPS ARE JUSTIFIED THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... DEEP LAYERED RIDGING WILL DOMINATE THE PATTERN IN THE EXTENDED RANGE. REINFORCING CANADIAN HIGH PRESSURE WILL MAINTAIN BELOW NORMAL TEMPS WITH LOWS IN THE MID/UPPER 50S AND HIGHS IN THE UPPER 70S WITH MAINLY DRY CONDITIONS. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... KCHS...SHOWERS AND MVFR CIGS ARE EXPECTED TO IMPACT THE TERMINAL OCCASIONALLY THROUGH THE MORNING HOURS. SMALL CHANCES FOR IFR CONDITIONS...THEY LIKELY WOULD BE VERY BRIEF AND NO FOG CONCERNS. LOW CONFIDENCE ON TIMING CHANCES FOR RAIN LATER TODAY WITH A COMPLEX SYNOPTIC SETUP AND A SEEMINGLY EXCELLENT COMBO OF DEEP MOISTURE AND UPPER DYNAMICS. OUTSIDE OF SHOWER AREAS...WE ARE MOST LIKELY TO BE VFR THROUGH 06Z TUE. KSAV...LOW CONFIDENCE WITH REGARDS TO FORECASTING THE ELEMENTS THROUGH THIS EVENING GIVEN THE TERMINALS PROXIMITY TO SEVERAL DEEP MOISTURE SOURCES AND MODEL DISCREPANCIES WITH REGARD TO COVERAGE AND TIMING OF RAIN. WE MAINTAINED PERSISTENCE WITH THE PREVIOUS TAF INDICATING THE BEST CHANCES OF RAIN FROM LATE MORNING THROUGH MID AFTERNOON BUT IT COULD BE LATER OR LESS THAN PROJECTED. CIGS WILL MAINLY BE VFR OVERNIGHT BUT LATE NIGHT THROUGH MID MORNING THERE IS A CHANCE FOR MVFR/IFR CIGS TO STREAM THROUGH BUT NO FOG CONCERNS. EXTENDED AVIATION OUTLOOK...OCCASIONAL FLIGHT RESTRICTIONS ARE EXPECTED MONDAY AFTERNOON/NIGHT DUE TO MOISTURE/SHOWERS ALONG A COLD FRONT. THE PROBABILITY FOR FLIGHT RESTRICTIONS...MAINLY IN LOW CEILINGS...HAS INCREASED IN THE WAKE OF COLD FROPA TUESDAY INTO WEDNESDAY. && .MARINE... OVERNIGHT...CONDITIONS ACROSS THE LOCAL WATERS WILL STEADILY WORSEN AS WINDS/SEAS INCREASE. AS THE APPROACHING COLD FRONT DRAWS CLOSER...THE PRESSURE GRADIENT WILL TIGHTEN AND RESULT IN STRENGTHENING SOUTHERLY FLOW. 15-20 KT WINDS WILL BE WIDESPREAD AND SHOULD REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THANKS TO THE WARM ADVECTION REGIME LIMITING GUST POTENTIAL. SEAS WILL CORRESPONDINGLY RISE AS WELL BY LATE TONIGHT...BECOMING 3-5 FT WITHIN 20 NM AND A SOLID 5 FT BEYOND. AHEAD OF AN APPROACHING COLD FRONT...EXPECT ELEVATED SOUTHERLY WINDS/SEAS MONDAY. 06/12Z GUIDANCE SUGGESTS THAT WINDS CAPPED AT 20 KT AND SEAS CAPPED AT 5 FT...JUST BELOW SMALL CRAFT ADVISORY LEVELS...WILL SUFFICE. WITHIN THE FRONTAL TROUGH MONDAY NIGHT...A WEAK PRESSURE GRADIENT AND LIGHT/VARIABLE WINDS COULD PREVAIL FOR SEVERAL HOURS. THEN...A STRONG COLD FRONT WILL PUSH THROUGH THE WATERS FROM NORTH TO SOUTH LATE MONDAY NIGHT INTO TUESDAY. IN THE WAKE OF COLD FROPA...NORTH/NORTHEAST WINDS WILL SURGE INTO THE WATERS. 06/12Z GUIDANCE STRONGLY SUGGESTS THAT THE TIGHTENING SURFACE PRESSURE GRADIENT AND DEEPENING MARINE LAYER MIXING PRODUCED BY COLD AIR ADVECTION WILL SUPPORT SMALL CRAFT ADVISORY WINDS/SEAS MOST AREAS TUESDAY INTO WEDNESDAY AND PERHAPS INTO LATE WEEK AS ELEVATED SEAS PERSIST BEYOND 20 NM. IN FACT...THERE IS A LOW PROBABILITY FOR THE GRADIENT TO TIGHTEN SUFFICIENTLY BETWEEN LOW PRESSURE SOUTH/SOUTHEAST OF THE WATERS AND HIGH PRESSURE TO THE NORTH TO SUPPORT GALE FORCE GUSTS ESPECIALLY OVER GA WATERS TUESDAY/TUESDAY NIGHT. RIP CURRENTS...AFTER A COLD FRONT ADVANCES THROUGH THE REGION...SUSTAINED NE WINDS COULD CONTRIBUTE TO AN ELEVATED RIP CURRENT RISK ON AREA BEACHES TUESDAY THROUGH LATE WEEK. && .TIDES/COASTAL FLOODING... BEGINNING TUESDAY...ASTRONOMICAL HIGH TIDES COULD COMBINE WITH PERSISTENT/ELEVATED NORTHEAST WINDS TO PRODUCE MINOR SALTWATER INUNDATION IN LOW-LYING AREAS NEAR THE COAST AROUND THE TIMES OF THE LATE MORNING/EARLY AFTERNOON HIGH TIDES THIS WEEK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...SPR LONG TERM...JRL AVIATION... MARINE.... TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
925 PM EDT TUE OCT 8 2013 .SYNOPSIS... HIGH PRESSURE IS CENTERED OVER SOUTHERN QUEBEC. LOW PRESSURE EAST OF GEORGIA WILL TRACK NORTH AND IMPACT THE MID-ATLANTIC REGION WEDNESDAY THROUGH FRIDAY...BRINGING UNSETTLED CONDITIONS. THE LOW WILL SLOWLY EXIT THE REGION THIS WEEKEND. && .NEAR TERM /THROUGH WEDNESDAY/... THE COMBO OF LOW PRES OFF THE GA CST AND HIGH PRES NEAR MONTREAL HAS CREATED A NERN MOISTURE FLOW INTO THE MID ATLC...WHICH IS BEING MANIFESTED IN XTSNV CLD CVR ACROSS THE FCST AREA. PCPN CURRENTLY XTNDS AS FAR N AS THE BORDER OF ERN VA/NC. HRRR SHOWS THE RA MOVG INTO SRN MD ARND 12Z. LOWS WILL RANGE FROM THE U30S/L40S OVER THE RIDGETOPS OF THE ALLEGHENY HIGHLANDS TO LM50S ALONG AND EAST OF I-95. ALSO ADDED CHC POPS TO LWR SRN MD FOR WED MRNG. THE REMNANTS OF WHAT WAS TROPICAL STORM KAREN WILL COMBINE WITH AN UPPER-LEVEL LOW OVER THE MID-ATLANTIC...CAUSING COASTAL LOW PRESSURE TO DEVELOP OFF THE MID-ATLANTIC COAST WEDNESDAY. ERLY FLOW WILL CAUSE PLENTY OF MOISTURE TO MOVE IN FROM THE OCEAN. THE BEST CHANCE FOR RAIN WILL BE ACROSS LOWER SOUTHERN MARYLAND INTO THE VIRGINIA PIEDMONT WEDNESDAY AFTERNOON...CLOSER TO THE COASTAL LOW. MAX TEMPS WEDNESDAY WILL RANGE FROM THE UPPER 50S IN THE MOUNTAINS TO THE LOWER AND MIDDLE 60S ACROSS MOST OTHER LOCATIONS. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... THE COASTAL LOW WILL CONTINUE TO SLOWLY DRIFT NORTH OFF THE MID- ATLANTIC COAST NEAR THE VIRGINIA/NORTH CAROLINA BORDER WEDNESDAY NIGHT THROUGH THURSDAY. PLENTY OF MOISTURE WILL CONTINUE TO MOVE IN OFF THE ATLANTIC. THE MOISTURE WILL COMBINE WITH FORCING FROM AN UPPER-LEVEL LOW OVERHEAD TO BRING RAIN ACROSS MOST LOCATIONS. HOWEVER...THERE IS STILL A HIGH DEGREE OF UNCERTAINTY AS TO HOW FAR WEST THE RAIN WILL MAKE IT...AND THAT DEPENDS ON THE EXACT TRACK OF THE COASTAL LOW. THEREFORE...POPS ARE LOWER ACROSS THE WESTERN PORTION OF THE CWA. MAX TEMPS THURSDAY ARE FORECAST TO BE IN THE LOWER 60S ACROSS MOST AREAS...BUT FOR LOCATIONS THAT RECEIVE PLENTY OF RAINFALL...TEMPS MAY NOT MAKE IT OUT OF THE 50S. THE LOW WILL REMAIN CUTOFF FROM THE JETSTREAM THURSDAY NIGHT...ALLOWING FOR THE ONSHORE FLOW TO CONTINUE. MORE CLOUDS ALONG WITH RAIN IS LIKELY THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... FCST CONFIDENCE IS LOWER THAN NORMAL FOR FRI AND THIS WEEKEND AS GUIDANCE IS HAVING A DIFFICULT TIME SIMULATING THE EXIT OF THE UPPER LOW AND THE COASTAL LOW. THE LOW PREDICTABILITY SKILL IS EVIDENT IN THE HIGH MODEL SPREAD AND ALSO THE RUN TO RUN INCONSISTENCIES WITH EACH MODEL. EVEN IF THE LOW IS QUICKER TO EXIT...AN ONSHORE FLOW IS LIKELY TO PERSIST KEEPING LOW-LEVEL MOISTURE TRAPPED UNDERNEATH AN INVERSION. THEREFORE...THE FORECAST WILL CONTINUE TO FEATURE PLENTY OF CLOUDS ALONG WITH THE CHANCE FOR RAIN. THE LOW SHOULD FINALLY MOVE AWAY FROM THE AREA EARLY NEXT WEEK. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS ARE EXPECTED THROUGH TONIGHT. NORTH-NORTHEAST WINDS THIS AFTERNOON WILL GUST AROUND 15 KNOTS. A COASTAL LOW WILL MOVE UP THE MID-ATLANTIC COAST AND IT WILL STALL OUT NEARBY THROUGH THE WEEKEND. CLOUDS WILL INCREASE WEDNESDAY...BUT VFR CONDITIONS ARE EXPECTED. HOWEVER...CIGS/VSBYS WILL DETERIORATE WEDNESDAY NIGHT AND IFR CIGS/VSBYS ARE POSSIBLE LATE WEDNESDAY NIGHT THROUGH THE WEEKEND. RAIN IS LIKELY TO MOVE INTO THE TERMINALS WEDNESDAY NIGHT AND THURSDAY...AND RAIN IS POSSIBLE FRIDAY THROUGH THE WEEKEND AS WELL. && .MARINE... HIGH PRESSURE WILL REMAIN OVER SOUTHERN QUEBEC WHILE COASTAL LOW PRESSURE REMAINS OFF THE GA COAST CREATING NORTHEAST WINDS. A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH TONIGHT FOR THE MARYLAND CHESAPEAKE BAY SOUTH OF POOLES ISLAND AND THE LOWER TIDAL POTOMAC RIVER FROM COBB ISLAND TO SMITH POINT. THE GRADIENT WILL STRENGTHEN WEDNESDAY THROUGH WEDNESDAY NIGHT AS THE COASTAL LOW DRIFTS NORTHWARD. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE WATERS. THE STRONG GRADIENT WILL REMAIN IN PLACE INTO THURSDAY BEFORE SLOWLY WEAKENING DURING THE LATTER PORTION OF THE WEEK INTO THE WEEKEND. HOWEVER...SMALL CRAFT ADVISORIES WILL LIKELY STILL BE NEEDED THURSDAY THROUGH SATURDAY FOR PORTIONS OF THE WATERS. ALSO...THE PRESSURE GRADIENT MAY BE STRONG ENOUGH FOR GALE FORCE WINDS WEDNESDAY NIGHT INTO THURSDAY ACROSS PORTIONS OF THE WATERS. && .TIDES/COASTAL FLOODING... LOW PRESSURE WILL SLOWLY MOVE UP THE MID-ATLANTIC COAST WEDNESDAY AND THURSDAY. A PERSISTENT ONSHORE FLOW IS EXPECTED DURING THIS TIME AND TIDAL ANOMALIES WILL INCREASE. COASTAL FLOODING IS POSSIBLE WEDNESDAY AND THURSDAY. THE ONSHORE FLOW MAY CONTINUE FRIDAY THROUGH THE WEEKEND...KEEPING WATER LEVELS ELEVATED. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ531>534- 537-539>543. SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 6 AM EDT THURSDAY FOR ANZ530-535-536-538. && $$ UPDATE...WOODY! PRVS...BJL/JRK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
347 PM EDT MON OCT 7 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 346 PM EDT MON OCT 7 2013 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER THE GREAT LKS SANDWICHED BTWN UPR RDG OVER THE ROCKIES/WRN PLAINS AND ANOTHER RDG OFF THE E COAST. H925-85 THERMAL TROF ASSOCIATED WITH REINFORCING SHRTWV DIGGING INTO THE UPR LKS AND MOIST LLVLS SHOWN ON THE 12Z YPL RAOB HAVE BROUGHT QUITE A BIT OF CLD COVER TO MUCH OF THE CWA...AND THERE HAVE EVEN BEEN A FEW -SHRA...MAINLY OVER THE E HALF OF UPR MI. THE CLDS HAVE BEEN MORE SCT NEAR THE WI BORDER AND ESPECIALLY THE SCENTRAL...WHERE LLVL NW FLOW BTWN SFC LO PRES MOVING INTO QUEBEC AND HI PRES IN THE PLAINS IS DOWNSLOPING. MAIN FCST CONCERNS IN THE SHORT TERM ARE MAINLY LO CLD TRENDS/TEMPS. TNGT...SINCE THE UPR PATTERN IS RATHER PROGRESSIVE...MODELS SHOW UPR RDG AXIS TO THE W SLIDING E AND OVER THE MS RIVER VALLEY BY 12Z TUE... WITH SFC HI PRES SHIFTING INTO THE OH RIVER VALLEY. ALTHOUGH LINGERING LLVL THERMAL TROF/CYC NW FLOW WL MAINTAIN SOME LO CLDS OVER THE E HALF THIS EVNG...ARRIVAL OF SFC HI PRES RDG AXIS AND BACKING LLVL FLOW TO THE W AND THEN SW WL CAUSE SKIES TO TURN MOCLR. THERE COULD BE SOME MID/HI CLDS OVER MAINLY THE NW LATER IN THE RETURN SW FLOW...BUT THE BULK OF THIS CLD SHOULD STAY IN CANADA. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR/WINDS LIGHTER THRU THE NGT. TUE...THE CWA WL BE DOMINATED BY A STRONG SW FLOW UNDER SHARPENING PRES GRADIENT BTWN SFC HI PRES MOVING INTO THE MID ATLANTIC STATES AND SFC LO PRES IN SCENTRAL CANADA RIDING OVER THE UPR RDG. ALTHOUGH SOME DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THIS FEATURE/WAD WL BRUSH THE NW CWA...FCST SDNGS SHOW SO MUCH LO-MID DRY AIR THAT THE ONLY IMPACT WL BE SOME HI CLDS. 12Z NAM/GFS SHOW SW H925 WINDS INCRSG TO 45-50 KTS IN THE AFTN OVER THE WRN CWA TO THE S OF PRES FALL CENTER OVER NW ONTARIO E OF THE SFC LO CENTER. MIXING TO H925 ON FCST SDNGS YIELDS HI TEMPS APRCHG 70 OVER THE W AND HINTS SOME WIND GUSTS MAY AT LEAST APRCH ADVY CRITERIA AT EXPOSED LOCATIONS OVER THE W. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 346 PM EDT MON OCT 7 2013 WITH THE UPPER TROUGH PEELING OUT OF THE UPPER GREAT LAKES REGION TONIGHT...AN UPPER RIDGE WILL BUILD OVER THE EASTERN CONUS AND REMAIN THROUGH THE END OF THE WORK WEEK. WITH A SURFACE HIGH OVER THE NEW ENGLAND STATES AND A LOW MOVING THROUGH CENTRAL CANADA...SOUTH-SOUTHWESTERLY FLOW WILL PULL WARM AIR OVER THE AREA. THIS WILL LEAD TO ABOVE NORMAL TEMPERATURES (GENERALLY IN THE MID 60S TO LOWER 70S) THROUGH THE END OF THE WORK WEEK. AS FOR WEATHER...EXPECT DRY CONDITIONS DURING THIS PERIOD WITH GENERALLY MOSTLY CLEAR SKIES. IT WILL STILL BE A LITTLE BREEZY ON WEDNESDAY AS THE PRESSURE GRADIENT IS GRADUALLY WEAKENING DUE TO THE LOW IN CANADA WEAKENING WHILE SHIFTING INTO THE CANADIAN MARITIMES. THERE ARE SOME HINTS OF FOG IN THE NAM/SREF OVER THE SOUTH CENTRAL AND EAST FOR WEDNESDAY NIGHT INTO THURSDAY MORNING. THE WEAKENING OF THE PRESSURE GRADIENT OVER THE AREA THAT STARTS ON WEDNESDAY WILL CONTINUE INTO WEDNESDAY NIGHT AND THURSDAY. SINCE SKIES WILL BE CLEAR AND IT SEEMS LIKE A BETTER RADIATIONAL COOLING NIGHT THAT MAY NOT BE TOO UNREASONABLE BUT DIDN/T ADD ANY FOG AT THIS TIME. AN UPPER TROUGH THAT DIVES INTO THE SOUTHWESTERN CONUS AROUND MID WEEK WILL BE THE MAIN WEATHER MAKER FOR THIS WEEKEND. THIS TROUGH WILL EJECT NORTHEAST INTO THE PLAINS ON FRIDAY AND THEN INTO THE UPPER MISSISSIPPI VALLEY FRIDAY NIGHT INTO SATURDAY. THE SURFACE LOW WILL FOLLOW A SIMILAR TRACK BUT THE CWA SHOULD STILL SEE AN ASSOCIATED COLD FRONT AND SHOWERS SLIDE ACROSS THE AREA ON SATURDAY. WILL CONTINUE TO SHOW THAT LINE OF SHOWERS SLIDING ACROSS THE CWA LATE FRIDAY NIGHT AND SATURDAY WITH CHANCE POPS. DID PUT IN A MENTION OF A RUMBLE OF THUNDER INTO THE GRIDS OVER THE SOUTH CENTRAL...AS THERE IS A POCKET OF MARGINAL MUCAPE VALUES ALONG THE FRONT (ALONG WITH SHOWALTER APPROACHING ZERO). BEHIND THE UPPER TROUGH...MODEL DIFFERENCES REALLY BEGIN TO GROW ON THE SMALLER SCALE FEATURES AFFECTING THE AREA. BUT THE LARGER SCALE IDEA OF AN UPPER TROUGH OVER THE WESTERN 2/3RDS OF THE CONUS AND THE UPPER GREAT LAKES REGION BEING ON THE EASTERN EDGE OF THE TROUGH. 00Z/12Z ECMWF/GEM RUNS ARE SHOWING A SECONDARY SHORTWAVE EJECTING FROM THE UPPER TROUGH AND THROUGH THE UPPER GREAT LAKES REGION ON SUNDAY INTO SUNDAY EVENING. 12Z GFS (LIKE IT/S PREVIOUS RUN) STILL HOLDS ONTO THE DRIER IDEA AND NO SHORTWAVE MOVING THROUGH. SINCE IT IS STILL A WAYS OFF...WILL FOLLOW A HIGH END SLIGHT AND LOW END CHANCE CONSENSUS FOR THE POPS AND SEE WHICH WAY THE MODELS GO. IF THE GEM/ECMWF SOLUTION PANS OUT...COULD SEE A DECENT RAINFALL FOR PORTIONS OF THE CWA ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 122 PM EDT MON OCT 7 2013 LINGERING MVFR CIGS AT THE TAF SITES WL GIVE WAY TO VFR CONDITIONS THIS AFTN WITH DAYTIME HEATING/MIXING AND THE APRCH OF HI PRES. THE GUSTY NW WINDS WL DIMINISH BY THIS EVNG FOLLOWING THE LOSS OF DAYTIME HEATING AND THE ARRIVAL OF A WEAKER PRES GRADIENT ASSOCIATED WITH THE INCOMING HI PRES. ONCE THIS RDG SHIFTS TO THE E ON TUE... EXPECT GUSTY S WINDS TO DVLP UNDER SHARPENING PRES GRADIENT IN THE PRESENCE OF DAYTIME HEATING/MIXING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 346 PM EDT MON OCT 7 2013 EXPECT NW WINDS UP TO 20 TO 30 KTS LATE THIS AFTERNOON TO DIMINISH STEADILY W-E TONIGHT AS A HI PRES RIDGE MOVES ACROSS LAKE SUPERIOR. A STRONGER S FLOW...WITH WINDS UP TO 30 KTS...WILL THEN DOMINATE LATER TUE/TUE NIGHT AS THE HI PRES SHIFTS TO THE E AND A SHARPER GRADIENT BETWEEN THIS FEATURE AND A LO PRES SYSTEM MOVING THRU SCENTRAL CANADA GETS SITUATED OVER THE UPPER LAKES. PLAN ON LIGHTER S-SW WINDS WED THRU SAT AS THE HI TO THE E REBUILDS BACK TOWARD THE AREA...RESULTING IN A WEAKER GRADIENT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
125 AM EDT MON OCT 7 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE WRN CONUS AND A TROUGH FROM HUDSON BAY INTO NRN ONTARIO. THE PERSISTENT MID/UPPER LEVEL LOW HAD EDGED EASTWARD INTO ERN IA. AT THE SFC...LOW PRES WAS LOCATED OVER S CNTRL LAKE SUPERIOR WITH A COLD FRONT INTO CNTRL LOWER MI AND A TROUGH TO THE SW INTO SE MN. RAIN ASSOCIATED WITH A WEAK SHORTWAVE IN THE WARM CONVEYOR AHEAD OF THE COLD FRONT WAS LIFTING NNE THROUGH ERN CWA. OTHERWISE...RADAR INDICATED ONLY VERY WEAK RETURNS OVER THE WEST WITH SOME SPRINKLES OR DRIZZLE. FARTHER WEST...A NARROW BAND OF RAIN TO NEAR DLH WAS ASSOCIATED WITH THE MID LEVEL DEFORMATION/FGEN BAND/TROWAL ON THE NRN FLANK OF THE MID LEVEL LOW. VIS LOOP SHOWED CLEARING OVER SRN UPPER MI WITH THE ADVANCING DRY SLOT. TONIGHT...MODELS SUGGEST THAT THE NE MN RAIN BAND WILL CONTINUE TO SLOWLY SPREAD INTO WEST UPPER MI THIS EVENING AND GRADUALLY SHRINK OVERNIGHT...PER FCST 310KE SURFACE. THERE MAY ALSO BE A FEW LIGHT SHOWERS THROUGH CNTRL UPPER MI THIS EVENING AS THE DRY SLOT AREA GIVES WAY TO INCREASING CLOUDS WITH INCREASING 700-300 MB QVECTOR CONV AND LOW LEVEL CONV NEAR THE TROUGH. IN ADDITION...SOME LAKE ENHANCED SHOWERS MAY DEVELOP OVERNIGHT AS 850 MB TEMPS DROP TO AROUND 1C WITH NNW LOW CYCLONIC FLOW INCREASING. SO...CHANCE POPS WERE MAINTAINED OVER MOST OF THE CWA TONIGHT EVEN IF ONLY INTERMITTENT PERIODS OF RAIN DEVELOP. MONDAY...THE REMAINING SYNOPTIC AND LAKE ENHANCED PCPN OVER THE EAST IS EXPECTED TO DIMINISH DURING THE MORNING AS THE MID LEVEL QVECTOR CONV FORCING AND DEEPER MOISTURE DEPART TO THE EAST. OTHERWISE...GRADUAL CLEARING AND SOME SUNSHINE DURING THE AFTERNOON WILL BRING TEMPS AGAIN TO NEAR SEASONAL NORMALS IN THE UPPER 50S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 409 PM EDT SUN OCT 6 2013 QUIETER WEATHER WILL REPLACE THE UNSETTLED ACTIVITY OF THIS PAST WEEK STARTING MONDAY NIGHT. A 500MB RIDGE BUILDS ACROSS THE NORTHERN PLAINS BY 00Z TUESDAY...AND CONTINUES EASTWARD THROUGHOUT THE FORECAST PERIOD. SURFACE HIGH PRESSURE EXPANDS INTO THE GREAT LAKES DURING THE DAY TUESDAY...AND GRADUALLY CENTERS ITSELF OVER THE LOWER LAKES THROUGH FRIDAY AFTERNOON. THE ECMWF/GFS HAVE 925 MB TEMPS UP TO 14-15C FOR WEDNESDAY-FRIDAY AFTERNOON OUT WEST...WHICH PUTS HIGHS ROUGHLY IN THE UPPER 60S/NEAR 70. FOR THE REST OF THE AREA...EXPECT LOW TO MID 60S. BUMPED UP WINDS FOR TUESDAY AND WEDNESDAY TO ACCOUNT FOR TIGHTENING PRESSURE GRADIENT ACROSS UPPER MICHIGAN ASSOCIATED WITH THE SURFACE LOW MOVING JUST NORTH OF LAKE SUPERIOR AND HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES. THOUGH SOUTHERLY WINDS MAY GUST UP TO 20 KTS AND TEMPS WILL BE CLOSE TO 70...AFTERNOON RH WILL BE IN THE 35-40 PERCENT RANGE SO DO NOT EXPECT ANY FIRE WX CONCERNS. FRIDAY NIGHT INTO SUNDAY...A NEGATIVELY TILTED 500MB TROUGH/POSSIBLE CUT OFF LOW WILL DIVE INTO THE PLAINS. THIS WILL PROVIDE THE NEXT CHANCES FOR PRECIPITATION ACROSS UPPER MICHIGAN. RECENT MODEL RUNS HAVE THE SFC LOW PRESSURE SYSTEM MOVING NORTHEAST INTO HUDSON BAY BY SUNDAY MORNING...BRINGING A COLD FRONT ACROSS UPPER MI. BOTH THE GFS/ECMWF HAVE THIS...THOUGH THERE ARE DIFFERENCES IN TIMING...WITH THE GFS BRINGING THE FRONT THROUGH FRIDAY NIGHT AND THE ECMWF BRINGING IT THROUGH SATURDAY AFTERNOON. EVEN MORE SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF SHOW UP ON SUNDAY AS ANOTHER TROUGH APPROACHES FROM THE WEST. THE GFS BRINGS SATURDAYS FRONT OUT OF UPPER MICHIGAN BY 12Z SUNDAY...AND THE DRY SLOT MOVES IN OVERHEAD WHICH ENDS PRECIPITATION. BY 00Z MONDAY IT HAS A SHORTWAVE SLIDING INTO THE DAKOTAS AND PRECIPITATION MOVING INTO WESTERN LAKE SUPERIOR OUT AHEAD OF IT. THE ECMWF KEEPS A STRONGER RIDGE OVER THE LOWER LAKES AND NEW ENGLAND STATES FOR SATURDAY AND SUNDAY...SO THE PROGRESSION OF THE FRONT ON SATURDAY IS SLOWER THAN THE GFS...AND IT STALLS OUT OVER CENTRAL/EASTERN UPPER MICHIGAN FOR SUNDAY. OVERALL...GENERAL CHANCE-SLIGHT CHANCE POPS ARE IN THE FORECAST FOR THESE DAYS. IT SEEMS BOTH MODELS HAVE BEEN FAIRLY INCONSISTENT FROM RUN TO RUN ON THE WEEKEND SOLUTION...SO WILL NOT GET CUTE WITH TIMING UNTIL THINGS IRON THEMSELVES OUT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 125 AM EDT MON OCT 7 2013 WITH LOW PRES CONTINUING TO EXIT TO THE E OF LAKE SUPERIOR...DRIER AIR/CLEARING IS MAKING STEADY PROGRESS ACROSS WRN LAKE SUPERIOR PER SATELLITE IMAGERY. KIWD SHOULD REMAIN VFR FOR THE REMAINDER OF THE NIGHT. AT KCMX...STRATOCU SHOULD SCATTER OUT...RESULTING IN MVFR CONDITIONS BECOMING VFR OVER THE NEXT FEW HRS. MVFR CIGS WILL LIKELY RETURN AT KIWD/KCMX FOR A TIME THIS MORNING INTO EARLY AFTN AS DAYTIME HEATING GENERATES STRATOCU. CONDITIONS WILL THEN BECOME VFR IN THE EARLY/MID AFTN AS DRIER AIR ARRIVES. AT KSAW...DRIER AIR WILL BE SLOWER TO ARRIVE AND MAY RESULT IN MVFR CIGS LINGERING THRU EARLY AFTN. VFR CONDITIONS WILL THEN PREVAIL THRU THE REMAINDER OF THE FCST PERIOD. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 409 PM EDT SUN OCT 6 2013 NNW WINDS AT 20 TO 30 KNOTS ARE EXPECTED TO DEVELOP LATE TONIGHT INTO MONDAY AS THE LOW PRES TROUGH OVER THE UPPER LAKES MOVES OFF TO THE EAST AND THE GRADIENT TIGHTENS ACROSS THE AREA. A HIGH PRESSURE RIDGE WILL THEN BUILD EAST INTO THE UPPER GREAT LAKES FOR MONDAY NIGHT WITH WINDS DROPPING BELOW 25KTS. AT THIS HIGH SHIFTS EAST ON WEDNESDAY...SOUTHERLY FLOW WILL DEVELOP OVER THE UPPER GREAT LAKES AS A LOW PRESSURE SYSTEM MOVES THROUGH CENTRAL CANADA. AT THIS TIME...THE SOUTHERLY FLOW LOOKS TO STAY BELOW 25KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MCD AVIATION...ROLFSON MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1232 AM CDT MON OCT 7 2013 .UPDATE... ISSUED AT 1017 PM CDT SUN OCT 6 2013 SOME PATCHY RADIATIONAL FOG HAS DEVELOPED OVER THE ARROWHEAD OF MINNESOTA. DEWPOINT DEPRESSIONS AROUND SUNSET WERE LESS THAN 10 DEGREES FOR MOST OF THE FORECAST AREA...EXCEPT FOR THE FAR NORTHWEST COUNTIES. THEN...AS OF 9PM SOME DRIER AIR HAD FILTERED IN FROM THE NORTHWEST AND THE BETTER DEWPOINT DEPRESSIONS REMAIN IN THE SAME AREAS. HAVE PUT IN PATCHY TO AREAS OF FOG INTO THE GRIDS FOR THE REST OF THE NIGHT FOR A FAIRLY LARGE PORTION OF THE FORECAST AREA...AND AM ALSO IN THE PROCESS OF UPDATING TERMINAL FORECASTS AS WELL. UPDATE ISSUED AT 641 PM CDT SUN OCT 6 2013 SOME MINOR ADJUSMENTS TO EVENING FORECAST...MAINLY FOR CLOUD TRENDS AND TEMPERATURES FOR THE NEXT FEW HOURS. HAVE SOME CONCERNS FOR THE RECENT RAINFALL SETTING UP GOOD PRECONDITIONS FOR FOG...WITH PLENTY OF LOW LEVEL MOISTURE AND LIGHT NORTHWEST WINDS. CURRENTLY GUIDANCE INDICATES NO FOG IS LIKELY TO FORM. EXPERIENCE BEGS TO DIFFER. FOR NOW WILL MONITOR LOW LEVEL MOISTURE PARAMETERS AND WINDS...AND RE-EVALUATE HERE BEFORE 10 PM. ALSO UPDATED AVIATION SECTION BELOW. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 MID LEVEL DEFORMATION ZONE EVIDENT ON SATELLITE AND RADAR ACROSS THE CWA. A LINE OF LIGHT RAIN/DRIZZLE EXTENDED FROM THE ARROWHEAD THROUGH AITKIN INTO SOUTHWEST MINNESOTA. THE HRRR HAS BEEN SHOWING THIS BAND DEVELOPING TODAY...BUT WAS A BIT TOO STRONG AND SLOW WITH IT. WE HAVE CHANCE FOR RAIN OVER OUR FAR EASTERN MN CWA AND NORTHWEST WISCONSIN THIS EVENING...AND DIMINISH OVERNIGHT. ANY RAINFALL SHOULD BE RATHER LIGHT...FROM A TRACE TO A COUPLE HUNDREDTHS OF AN INCH. CLEARING WAS ALSO WORKING INTO OUR WESTERN CWA...AND THAT SHOULD CONTINUE AS WELL THROUGH THE NIGHT. WE DO DECREASE SKY COVER TO CLEAR TO PARTLY CLOUDY OVERNIGHT...WITH LOWS IN THE MID THIRTIES TO AROUND FORTY. WE DO NOT EXPECT WINDS TO DECOUPLE OVER A LARGE AREA...BUT A FEW FAVORED LOCATIONS LIKELY WILL SUCH AS KHIB/KBFW AND WE LOWERED TEMPS A BIT MORE THERE. SURFACE HIGH PRESSURE WILL LEAD TO PARTLY TO MOSTLY SUNNY SKIES MONDAY WITH TEMPERATURES WARMING INTO THE UPPER FIFTIES TO LOWER SIXTIES. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 329 PM CDT SUN OCT 6 2013 THE WESTERN GREAT LAKES REGION WILL BE SITUATED BETWEEN THE DEPARTING RIDGE AND AN APPROACHING NEGATIVELY TILTED LONG WAVE TROUGH THROUGH THE TUESDAY-FRIDAY TIME FRAME. THIS WILL RESULT IN AN INCREASING SW FLOW WITH A RETURN TO UNSEASONABLY WARM H92-H85 TEMPS BY MID WEEK. HAVE INCREASED THE SOUTH WINDS TUESDAY AS LATEST MODEL RUNS ARE IN GOOD AGREEMENT THAT A 40-50 KT LLJ PUSHES OVER MINNESOTA THROUGH TUESDAY AFTERNOON. LATEST NAM BUFR SOUNDINGS AT LOCATIONS ACROSS THE DLH CWA SHOW WINDS AROUND 35 KT IN THE MIX LAYER TUESDAY AFTERNOON AS TEMPERATURES ARE EXPECTED TO WARM INTO THE UPPER 60 TO LOW 70S. HOWEVER...HIGHER GUSTS TO 40 KT ARE NOT OUT OF THE QUESTION IF TEMPERATURES WARM JUST A FEW DEGREES HIGHER ALLOWING FOR DEEPER MIXING. RAIN CHANCES RETURN TO THE FCST FRIDAY NIGHT/SATURDAY AS A STRONG VORT MAX /WITH CLOSED H85-H50 LOW/ ROUNDS THE BASE OF THE LONG WAVE TROUGH AND LIFTS INTO THE UPPER MIDWEST. THIS LOW WILL BRING CLOUDS AND ONGOING RAIN CHANCES TO THE NORTHLAND THROUGH MUCH OF THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1232 AM CDT MON OCT 7 2013 A FEW TERMINALS HAVE DEVELOPED SOME FOG THIS EVENING WITH LIGHT WINDS...RECENT RAINFALL BOOSTING LOW LEVEL MOISTURE AND RISING PRESSURES. EXPECT FOG TO EVENTUALLY AFFECT ALL 5 TERMINALS. KHYR...KHIB ARE LIKELY TO HAVE THE WORST CONDITIONS WITH LIFR VSBYS AND CIGS FOR AT LEAST A FEW HOURS. BETTER CONDITIONS ELSEWHERE...BUT AT LEAST A SHORT PERIOD OF IFR VSBYS ARE POSSIBLE. ONCE FOG CLEARS BY 15Z MONDAY MORNING...EXPECT VFR CONDITIONS FOR THE REST OF THE TAF PERIOD WITH LIGHT NORTHWEST WINDS TURNING SOUTH AFTER 00Z...STILL LESS THAN 8KTS. && .PRELIMINARY POINT TEMPS/POPS... DLH 42 67 48 66 / 0 0 0 0 INL 41 69 46 67 / 0 0 10 10 BRD 44 72 50 70 / 0 0 0 0 HYR 39 70 48 70 / 0 0 0 0 ASX 43 70 50 69 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...LE SHORT TERM...MELDE LONG TERM...GRANING AVIATION...LE
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1104 PM MDT Sun Oct 6 2013 ...UPDATE TO AVIATION... FOR THE 06Z TAF. VFR conditions will prevail at all terminals through the effective period. Gusts have subsided for now but will begin to increase again late Monday morning. Gusts will once again be strongest over north-central MT through the late evening hours. Gusts will subside near 00z. A surface cold front will push across the region late in the effective period with west/northwest winds increasing for a few hours behind the front. Foltz .PREV DISCUSSION... /ISSUED 900 PM MDT Sun Oct 6 2013/ Have made minor adjustments to the sky and wind grids and will issue an update this evening. Surface winds have decreased over the plains and have adjusted accordingly. The RUC continues to indicate a tightening of the surface gradient after 07z and HRRR analysis also supports mid level winds strengthening around this time along the Northern Rocky Mountain Front. This gives some corroboration for the high wind warning that goes in effect for this area at 09z. A chinook arch remains in place adjacent to the northern front range and have adjusted sky grids to better define its location. Temperatures look reasonable. Emanuel && .PRELIMINARY POINT TEMPS/POPS... GTF 48 70 42 53 / 0 0 0 10 CTB 46 67 40 53 / 0 0 10 20 HLN 36 68 39 53 / 0 10 10 20 BZN 30 67 36 54 / 0 0 0 20 WEY 24 56 31 47 / 0 0 0 20 DLN 33 63 33 49 / 0 0 10 20 HVR 40 74 41 60 / 0 0 0 10 LWT 37 71 37 53 / 0 0 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING from 3 AM Monday to 6 AM MDT Tuesday Northern Rocky Mountain Front. && $$ weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS RALEIGH NC
845 PM EDT TUE OCT 8 2013 .SYNOPSIS... A COMPLEX AREA OF LOW PRESSURE OFF THE SOUTHEAST COAST WILL MOVE SLOWLY NORTH UP THE MID-ATLANTIC COAST THROUGH LATE IN THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... AS OF 845 PM TUESDAY... TONIGHT... AND EARLY UPDATE TO THE FORECAST THIS EVENING TO LOWER POPS OVER THE NEXT FEW HOURS AS THE BAND OF MODERATE RAIN THAT COVERAGE THE CENTRAL CWA EARLIER TODAY AS SHIFTED SOUTH INTO SC. MOST OF THE RAIN IS NOW FOCUSED ALONG THE COAST WHERE BETTER LOW LEVEL FORCING AND WARM CONVEYOR BELT RESIDE. WATER VAPOR IMAGERY SUGGESTS THE CENTER OF THE DEVELOPING UPPER LOW AND ASSOCIATED NUMEROUS VORT MAXIMA IS OVER SC...AND THE LATEST RAP SHOWS THE MOST PROMINENT AND INVERTED 500MB TROUGH/VORT MAX EXTENDING FROM SC TO THE NORTHEAST TOWARD THE OBX. AN UPPER LEVEL JET STREAK ALSO APPEARS TO BE SURGING NORTHWARD ALONG THE CAROLINA COAST ON THE EASTERN SIDE OF THE DEVELOPING UPPER LOW. WHILE MODELS HAVE PERFORMED POORLY THUS FAR WITH THIS SYSTEM...THERE IS AT LEAST DECENT AGREEMENT AMONG THE 18Z GFS AND 12Z ECMWF AND THE LATEST RAP IN THE BEST UPPER FORCING FOCUSING FROM THE TRIANGLE TO THE EAST AND NORTHEAST...WHERE THE AFOREMENTIONED VORT MAX AND LEFT EXIT REGION OF THE JET SHOULD COINCIDE WITH INCREASING ONSHORE MOISTURE TRANSPORT. WILL INDICATE INCREASING POPS ACROSS THE EAST AND NORTHEAST AFTER MIDNIGHT...THOUGH WITHOUT GOOD SUPPORT FROM THE HI-RES MODELS... CONFIDENCE IS NOT HIGH ENOUGH FOR A LARGE AREA OF CATEGORICAL POPS AT THIS TIME. MAY REEVALUATE AFTER THE 00Z UPPER-AIR ANALYSIS. ELSEWHERE...WILL MAINTAIN AT LEAST A SLIGHT CHANCE TO CHANCE OF LIGHT RAIN OR DRIZZLE. LOWS SHOULDN`T MOVE MUCH LOWER THAN THEIR CURRENT VALUES UNDER OVERCAST SKIES...WITH LOWER 50S WEST AND UPPER 50S EAST. -SMITH WEDNESDAY/WEDNESDAY NIGHT... PERIODS OF RAIN MIXED WITH SPRINKLES SHOULD PERSIST THROUGHOUT MUCH OF THE DAY WEDNESDAY AND INTO WEDNESDAY NIGHT WITH HIGHER POPS GRADUALLY SHIFTING NORTHWARD WITH THE UPPER LOW. HIGHS IN THE LOW TO MID 60S. EXPECT A SHARP EAST TO WEST CUT-OFF IN RAINFALL AMOUNTS...RANGING FROM AS HIGH AS AN INCH IN EAST(AND WHERE EVER PRECIP BANDS SETUP) TO POSSIBLY ONLY TRACE AMOUNTS IN THE TRIAD. LOWS TOMORROW TONIGHT AGAIN IN THE LOWER TO MID 50S. -CBL && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 250 PM TUESDAY... UNCERTAINTY CONTINUES TO EXIST WITH THE EXACT DETAILS OF EVOLUTION OF A SLOW MOVING UPPER LEVEL LOW AND ASSOCIATED SURFACE LOW NEAR OR JUST OFFSHORE. THE LOW(S) WILL NOT MOVE VERY MUCH THROUGHOUT THE ENTIRE PERIOD AS A BLOCKING PATTERN PERSISTS ACROSS THE NORTHERN ATLANTIC. NEVERTHELESS...THE BIG QUESTION IS WHERE THESE LOWS WILL ULTIMATELY TRACK...AS ANY SHIFT IN THE TRACK WILL HAVE IMPACTS ON PRECIPITATION COVERAGE. AT THIS TIME IT APPEARS THE DEEP MOISTURE MAY GRADUALLY SHIFT OUT OF THE AREA FROM THE SOUTHWEST TO NORTHEAST DURING THIS TIME FRAME AS THE LOW(S) SHIFT SLIGHTLY TO THE NORTHEAST. THIS WOULD ALSO ALLOW THE PRECIP TO GRADUALLY COME TO AN END FROM SOUTHWEST TO NORTHEAST LATE THURSDAY INTO FRIDAY. HOWEVER...WILL KEEP SLIGHT CHANCE POPS IN ACROSS THE NORTHEAST PORTION OF THE FORECAST AREA THROUGHOUT THE ENTIRE PERIOD DUE TO THE CLOSER PROXIMITY OF THE LOW. CLOUDS SHOULD ALSO ACCORDINGLY THIN OUT SOME...BUT AM NOT EXPECTING COMPLETE CLEARING BY ANY MEANS... ESPECIALLY ACROSS THE NORTHEAST. HOWEVER...THIS SHOULD BE ENOUGH TO ALLOW TEMPS TO FINALLY RISE SOME...BUT WILL STILL BE BELOW NORMAL...GENERALLY MID/UPPER 60S ON THURSDAY AND UPPER 60S TO NEAR 70 DEGREES ON FRIDAY (COOLEST NORTHEAST/WARMEST SOUTHWEST). OVERNIGHT LOWS ARE EXPECTED TO BE IN THE LOW/MID 50S. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 250 PM TUESDAY... THE LINGERING UPPER LEVEL LOW AND PERSISTENT NORTHEASTERLY FLOW WILL RESULT IN CONTINUED CLOUDY AND RELATIVELY COOL CONDITIONS FOR THE FIRST PORTION OF THE PERIOD...WITH GRADUALLY IMPROVING CONDITIONS BY LATE IN THE WEEKEND OR EARLY NEXT WEEK. NEVERTHELESS...FOR THE WEEKEND...THE OVERALL PRECIP CHANCES SHOULD BE RELATIVELY LOWER THAN EARLIER IN THE WEEK. MODELS DO CONTINUE TO HINT AT THE UPPER LOW (WHICH IS PROGGED TO HAVE MOVED NORTH OF THE AREA BY THIS POINT) TO SHIFT BACK TO THE SOUTH AND EAST SATURDAY INTO SUNDAY...MOVING ACROSS THE NORTHEASTERN PORTION OF THE FORECAST AREA. THEREFORE... WILL MAINTAIN AT LEAST SLIGHT CHANCE POPS ACROSS THE NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE WEEKEND...BEFORE RETURNING TO A DRY FORECAST BY EARLY NEXT WEEK AS WE FINALLY GET ON THE BACKSIDE OF THE LOW AS IT MOVES OFFSHORE AND HEIGHTS RISE ACROSS THE EAST COAST. TEMPS WILL ACCORDINGLY MODERATE THROUGH THE PERIOD WITH A RETURN TO SLIGHTLY ABOVE NORMAL TEMPS BY EARLY NEXT WEEK. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 750 PM TUESDAY... 24 HOUR TAF PERIOD: VERY LOW CONFIDENCE FORECAST FOR TONIGHT AS AN UPPER LEVEL LOW PRESSURE SYSTEM REMAINS STACKED OVER TOP OF A SURFACE LOW JUST OFF OF THE GEORGIA COAST. THE LOW IS EVIDENT ON THE CURRENT RADAR AS BANDING PRECIPITATION ACROSS THE TRIANGLE AND SOUTHWEST PIEDMONT MOVES SOUTHWESTWARD AND FURTHER TO THE EAST A SHIELD OF LIGHT PRECIPITATION MOVES NORTHEASTWARD ALONG THE CAROLINA COAST. SOME EARLIER HEAVIER SHOWERS EMBEDDED IN THE LIGHTER RAIN HAVE FOR THE MOST PART SUBSIDED BUT SOME MODERATE RAINFALL REMAINS ALONG THE ROUTE FROM KFAY TO KRWI. THESE TWO SITES WILL BE THE FOCUS FOR MUCH OF THE WEATHER THROUGH THE 24 HOUR TAF PERIOD. CONTINUED LIGHT RAIN WILL AFFECT THESE SITES OVERNIGHT AS THE LOW ROTATES THROUGH THE AREA. LATER TONIGHT...CEILINGS MAY FALL TO/REMAIN AT MVFR LEVELS AT KRWI AND KFAY BUT FURTHER TO THE NORTHWEST KRDU SHOULD REMAIN VFR BUT WILL BE RIGHT AROUND THE 3 KFT LEVEL AND MAY BOUNCE BETWEEN IFR/MVFR. THE TRIAD SITES ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. AFTER SUNRISE ON WEDNESDAY MVFR CEILINGS AND LIGHT RAIN MAY CONTINUE IN THE SOUTHEAST AS SEVERAL IMPULSES ROTATE AROUND THE UPPER LOW. HEAVIER SHOWERS MAY BE EMBEDDED IN THE LIGHTER RAINFALL. LATE WEDNESDAY MORNING EXPECT GUSTS OUT OF THE NORTHEAST TO ONCE AGAIN PICK UP AND BY AFTERNOON 20-25 KT GUSTS CAN BE EXPECTED AT ALL TAF SITES. GUSTS ARE EXPECTED TO CONTINUE THROUGH THE END OF THE TAF PERIOD. LONG TERM: WEATHER HAS THE POTENTIAL TO REMAIN UNSETTLED FOR THE REST OF THE WEEK AS THE LOW PRESSURE SYSTEM MEANDERS NEARLY STATIONARY OFF THE COAST. KRWI IS THE MOST LIKELY SITE TO BE AFFECTED BY THIS SYSTEM THE LONGEST. EARLY NEXT WEEK A SMALL UPPER LEVEL RIDGE PUSHES THE LOW JUST FAR ENOUGH OUT TO SEA TO CLEAR THINGS UP A BIT ACROSS THE CAROLINAS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL/SMITH SHORT TERM...KRR LONG TERM...KRR AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1253 PM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND MOVE ACROSS THE AREA TONIGHT. THE FRONT WILL STALL OFFSHORE WITH WEAK LOW PRESSURE MOVING ALONG IT THROUGH THE END OF THE WEEK WHILE HIGH PRESSURE EXTENDS OVER THE AREA FROM THE NORTH. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1250 PM MONDAY...SHOWERS WITH A FEW EMBEDDED TSTMS STARTING TO IMPACT AREAS OF OUR FAR WESTERN CWA. LATEST 3KM HRRR IS RIGHT ON THE MONEY WITH THE PLACEMENT OF THE PRECIPITATION AND SHOWS THAT IT WILL GRADUALLY OVERSPREAD THE REGION OVER THE NEXT 3 OR 4 HOURS. INSTABILITY AND SHEAR REMAIN FOCUSED NORTH AND WEST OF OUR CWA...BUT CANNOT RULE OUT SOME WIND GUSTS APPROACHING SEVERE CRITERIA IN SOME OF THE STRONGER STORMS OVER THE NEXT 3 TO 6 HOURS. TEMPERATURES HAVE LIKELY REACHED THEIR AFTERNOON HIGHS IN THE LOW TO MID 80S AND WILL LEVEL OFF AS CLOUDS AND PRECIPITATION INCREASES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... AS OF 330 AM MONDAY...NRN PORTION OF MID LVL TROF WILL LIFT N OF AREA TONIGHT...BUT SRN PORTION WILL STILL BE WORKING OVER SE US. WIDESPREAD SHOWERS AND ISOLD TSTMS EXPECTED TO AFFECT MAINLY WRN SECTIONS THIS EVENING. FRONT WILL GRADUALLY PUSH ACROSS AREA OVERNIGHT...AND DEVELOPING N TO NE LOW LVL WINDS COMBINED WITH LINGERING MID LVL ENERGY FROM S-SW WILL LEAD TO HIGHEST POPS OVER SRN PORTIONS AFTER MIDNIGHT. MOS BLEND FOR TEMPS...MAINLY LOW-MID 60S. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 330 AM MON...BY TUES MORNING THE SURFACE FRONT WILL BE OFFSHORE WITH HIGH PRESSURE BUILDING EAST OVER THE MID-ATLANTIC STATES. THE UPPER RIDGE OVER THE SOUTHERN CONUS WILL SHIFT EAST TOWARDS THE CAROLINAS AS THE REMNANTS OF TS KAREN SLOWLY MOVE OVER NORTHERN FL AND EVENTUALLY OFF THE GA/SC COAST. THE FRONT WILL STALL OFFSHORE WITH A SURFACE LOW DEVELOPING OFF THE COAST. THE LOW WILL SLOWLY MIGRATE NE ALONG/OFF THE COAST TUES NIGHT INTO THURS PRODUCING AN UNSETTLED PATTERN ACROSS THE REGION. INCREASED POPS TO NEAR CATEGORICAL TUES GIVEN GOOD MODEL AGREEMENT WITH GOOD MOISTURE AND STRONG SHORTWAVE ALOFT. KEPT CHANCE POPS ACROSS THE REGION WED THEN SLIGHT CHANCE INLAND/CHANCE EAST OF HWY 17 WED NIGHT INTO THURS AS THE LOW MIGRATES NE. THE SLOW EVOLUTION OF THIS PATTERN WILL LEAD TO A PROLONGED PERIOD OF GUSTY NE WINDS TO THE COASTAL OBX AREAS. UPPER LOW WILL DRIFT NORTH BY LATE WEEK TAKING BEST SHOWER CHANCES WITH IT. BEST POPS WILL RESIDE IN THE NORTHEAST DURING THIS PERIOD. THE UPPER LOW WILL SHIFT BACK OVER THE REGION SAT/SUN YIELDING MORE CLOUDS/CHANCES FOR PRECIP. FOR TEMPS...EXPECT BE BELOW CLIMO...ESPECIALLY FOR MAX TEMPS AS CLOUDS AND PRECIP KEEP TEMPS DOWN INTO THE UPPER 60S TO NEAR 70 INLAND. LOWS WILL GENERALLY BE IN THE 50S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... SHORT TERM /THROUGH 12Z TUESDAY/... AS OF 1250 PM MONDAY...SHOWERS AND SCATTERED TSTMS WILL BECOME WIDESPREAD THROUGH MID TO LATE AFTN AHEAD OF APPROACHING COLD FRONT AND CONTINUE THROUGH EVENING WITH CONDITIONS LOWERING TO MVFR. SRLY WINDS WILL GUST TO AROUND 20 KT AHEAD OF THE FRONT. MVFR CIGS WILL CONTINUE WITH PATCHY RAIN LATE TONIGHT AS WINDS SHIFT TO N-NE BEHIND FRONT. LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 320 AM MON...COLD FRONT WILL PUSH OFF THE NC COAST EARLY TUES MORNING WITH SHOWERS CONTINUING TUES INTO WED. UNFAVORABLE AVIATION CONDITIONS EXPECTED TO PERSIST TUES THROUGH WED WITH IFR CONDITIONS POSSIBLE AS MOIST NORTHEAST FLOW DEVELOPS WITH UPPER LOW LINGERING OVER THE VICINITY. WINDS WILL BE GUSTY AT TIMES AS WELL WITH HIGH PRESSURE INLAND AND LOW PRESSURE OVER THE WATERS PRODUCING A NE GRADIENT. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 1250 PM MONDAY...WINDS GRADUALLY STARTING TO RAMP UP OVER THE COASTAL WATERS AND SOUNDS AS THE FRONT EDGES CLOSER. MOST AREAS WILL BE IN THE 15 TO 20 KNOT RANGE WITH SEAS IN THE 3 TO 5 FOOT RANGE. WINDS/SEAS INCREASE A BIT MORE OVERNIGHT WITH FREQUENT GUSTS TO 25 KNOTS AND SEAS BUILDING TO AS HIGH AS 6 TO 7 FEET BY LATER THIS EVENING. WINDS/SEAS WILL ALSO BE ELEVATED IN CONVECTION. LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 315 AM MON...COLD FRONT WILL RESIDE JUST ALONG THE COAST BY EARLY TUES MORNING THEN SHIFT OFFSHORE THROUGHOUT THE DAY...WITH A STRONG NE SURGE OF WINDS EXPECTED TO BUILD SOUTH OVER THE WATERS. NE GRADIENT WILL PERSIST WED/THURS DUE TO HIGH PRESSURE OVER THE NORTHEASTERN CONUS AND WEAK SURFACE LOW/REMNANTS OF TS KAREN OFF THE SOUTHEASTERN COAST. NE WINDS WILL RANGE 20-25 KT TUES THROUGH WED AFTERNOON. SEAS WILL RESPOND BY BUILDING 5-8 FT TUES/TUES NIGHT ACROSS THE NORTHERN AND CENTRAL WATERS...WITH 4-7 FT EXPECTED ACROSS THE SOUTHERN WATERS. WEAK SURFACE LOW SHIFTS NORTH TO OFF THE NORTH CAROLINA COAST THURS INTO FRI...ACTING TO VEER WINDS MORE N/NW AND DIMINISH SPEEDS TO 10-20 KT...HOWEVER...SEAS WILL REMAIN ELEVATED THROUGH MID WEEK ESPECIALLY FROM DIAMOND SHOALS NORTH. USED A BLEND OF PREVIOUS FORECAST WITH LATEST NON-GFS MODEL BLEND FOR WINDS. FOR SEAS...UTILIZED LOCAL SWAN/NWPS THROUGH WED THEN VERY SMALL ADJUSTMENTS TO PREVIOUS SEAS FORECAST FOR THURS/FRI WHICH HAD ALREADY TAKEN INTO ACCOUNT THE KNOWN BIAS OF UNDER-FORECAST SEAS FOR NE/N FLOW ACROSS THE CENTRAL AND NORTHERN WATERS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 PM EDT THURSDAY FOR AMZ130-135. SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 4 AM EDT FRIDAY FOR AMZ152-154. SMALL CRAFT ADVISORY FROM 8 AM TUESDAY TO 4 PM EDT THURSDAY FOR AMZ156-158. SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 AM EDT FRIDAY FOR AMZ150. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...DAG AVIATION...JBM/CTC/DAG MARINE...JBM/DAG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
728 AM EDT MON OCT 7 2013 .SYNOPSIS... WIDESPREAD SHOWERS AND THUNDERSTORMS WILL OCCUR TODAY AHEAD OF A STRONG COLD FRONT WHICH WILL CROSS LATE TONIGHT. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THIS FRONT AND MOVE NEAR THE AREA TUESDAY AND WEDNESDAY...PRODUCING WIDESPREAD RAIN AND MUCH COOLER TEMPERATURES. A DRYING AND WARMING TREND WILL BEGIN LATE IN THE WEEK AS HIGH PRESSURE BUILDS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 730 AM MONDAY...RADAR TRENDS AND THE LATEST HRRR MODEL SUGGESTS THE CONVEYOR BELT OF SHOWERS WILL CONTINUE MOVING ACROSS EASTERN SOUTH CAROLINA AND THE LUMBERTON AREA FOR AT LEAST THE REMAINDER OF THE MORNING HOURS...GRADUALLY SHIFTING EAST TO INCLUDE THE MYRTLE BEACH-WHITEVILLE-ELIZABETHTOWN CORRIDOR BEFORE NOON. UNLESS ISOLATED CELLS DEVELOP OUT AHEAD OF THE MAIN LINE IT COULD BE AS LATE AS 4 PM BEFORE WILMINGTON GETS IN ON THE ACTION. NO CHANGES HAVE BEEN MADE TO TEMPERATURES. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... A STREAM OF SHOWERS ORIGINATING FROM THE GULF STREAM WATERS OFF THE GA/FL COAST CONTINUES TO MOVE NORTH INTO EASTERN SC EARLY THIS MORNING. SYNOPTIC MODELS 24 HOURS AGO WERE NOT ABLE TO CAPTURE THIS FEATURE...BUT RECENT HIGH-RESOLUTION MODELS LIKE THE HRRR AND NSSL WRF SEE IT WELL AND INDICATE THE "STREAMER" WILL CONTINUE THROUGH THE MORNING HOURS WITH SIGNIFICANT RAINFALL TOTALS POSSIBLE ACROSS EASTERN SOUTH CAROLINA. STRONG UPPER LEVEL LOW PRESSURE ACROSS THE SOUTHERN GREAT LAKES IS THE SAME SYSTEM RESPONSIBLE FOR THE RECORD-BREAKING EARLY SNOW ACROSS WESTERN SOUTH DAKOTA A COUPLE DAYS AGO. THIS UPPER SYSTEM WILL LIFT NORTHEAST...WHILE A VORTICITY MAXIMUM AT THE BASE OF THE UPPER TROUGH ALONG THE GULF COAST SLOWS AND BEGINS TO FORM A CLOSED LOW LATE TONIGHT. THE SURFACE PATTERN MIRRORS THE 500 MB CHART WITH AN EASTWARD-MOVING COLD FRONT LOCATED JUST AHEAD OF THE UPPER TROUGH. THIS FRONT WILL SLOW ITS PROGRESS AS SURFACE LOW PRESSURES DEVELOPS IN IN THE FLORIDA PANHANDLE. SHOWER AND T-STORM CHANCES ARE VERY HIGH TODAY...PROBABLY AT LEAST 90 PERCENT COVERAGE ACROSS THE EASTERN CAROLINAS. THIS MORNING`S HEAVY BAND OF SHOWERS ACROSS EASTERN SOUTH CAROLINA SHOULD SOAK THE PEE DEE AND INTERSTATE 95 CORRIDOR THROUGH MID-MORNING...SHIFTING EAST FROM MYRTLE BEACH THROUGH WHITEVILLE AND ELIZABETHTOWN BY NOON...THEN FINALLY REACHING THE CAPE FEAR AREA INCLUDING WILMINGTON BY THE MID-AFTERNOON HOURS. FROM A BROAD-SCALE PERSPECTIVE MANY AREAS SHOULD SEE TWO-THIRDS TO ONE INCH OF RAIN TODAY...BUT WITH TRAINING CONVECTION UNDOUBTEDLY A FEW SPOTS WILL RECEIVE 2-3 INCHES OR MORE. SEVERE WEATHER POTENTIAL IS NOT ZERO...BUT IS LESS THAN EXPECTED YESTERDAY DUE TO WEAKENING LOW-LEVEL WIND FIELDS AND OVERALL MODEST INSTABILITY. IN FACT IT APPEARS ISOLATED FLOODING MAY BECOME A LARGER FACTOR TO CONTEND WITH THAN SEVERE WEATHER. SHOULD A THUNDERSTORM BECOME SEVERE TODAY...WET MICROBURSTS APPEAR TO BE THE MOST SIGNIFICANT THREAT. TONIGHT THE PRESSURE GRADIENT BETWEEN THE LOW OVER NORTHERN FLORIDA AND HIGH PRESSURE STRENGTHENING OVER PENNSYLVANIA SHOULD PRODUCE A NORTHERLY SURGE THAT WILL REACH OUR AREA A FEW HOURS BEFORE SUNRISE. THIS SHALLOW COLD AIRMASS WILL UNDERCUT THE OTHERWISE WARM AND HUMID AIR PRESENT...PRODUCING GUSTY WINDS AND SUDDENLY FALLING TEMPERATURES. PRECIPITATION CHANCES WILL CONTINUE AS WELL... ESPECIALLY ALONG THE COAST...BUT ISENTROPIC PROCESSES WILL BECOME MORE DOMINANT WITH TIME AS INSTABILITY WANES AND VEERING LOW LEVEL WINDS ADVECT ATLANTIC MOISTURE BACK ONSHORE. POPS TONIGHT RANGE FROM 80 PERCENT ALONG THE COAST TO 60 PERCENT IN FLORENCE AND DARLINGTON. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...SLOW MOVING UPPER LOW WILL EJECT OUT OF THE GULF OF MEXICO AND DRIFT NORTHEAST THROUGH THE PERIOD...SPAWNING A WAVE OF LOW PRESSURE ALONG A COLD FRONT STALLED ON THE COAST. STRONG VORT MAX ACROSS SOUTHEAST TEXAS WILL MOVE INTO THE GULF AND THEN DRIFT NORTHEAST OVERHEAD THE CAROLINAS TUESDAY AND WEDNESDAY. THIS SPAWNS A SURFACE WAVE ALONG A COLD FRONT WHICH WILL BE STALLED RIGHT ON THE COAST...AND WILL KEEP UNSETTLED WEATHER THROUGH THE PERIOD. GUIDANCE IS IN GOOD AGREEMENT THAT BOTH TUESDAY AND WEDNESDAY WILL BE WET...A SIGNIFICANT CHANGE FROM MODELS LAST NIGHT. AS THE FRONT STALLS JUST OFFSHORE...ABUNDANT TROPICAL MOISTURE REMAINS IN PLACE. THIS SERVES AS THE FUEL FOR PERIODS OF MDT/HVY RAIN TUE AND WED AS THE UPPER LOW MOVES OVERHEAD. ADDITIONALLY...ISENTROPIC LIFT OVER THE DEVELOPING WEDGE-HIGH PRESSURE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS EASTERN PORTIONS OF THE CWA. WPC IS SHOWING WIDESPREAD 1-2 INCHES OF QPF...MOST ACROSS THE CAPE FEAR REGION TUE/WED. THIS MAY BE A BIT HIGH...BUT CERTAINLY SHOWS THE POTENTIAL WITHIN THE TROPICAL MOISTURE PLUME. IN ADDITION TO THE UNSETTLED WEATHER...TEMPS WILL BE WELL BELOW NORMAL BOTH TUE AND WED THANKS TO THE WEDGE HIGH PRESSURE AND CLOUDS/RAIN. STRONG LOW LVL CAA DEVELOPS EARLY TUESDAY...AND HAVE SHOWN AN ATYPICAL DIURNAL CURVE WITH MAX TEMPS BEING REACHED FIRST THING TUESDAY MORNING...BEFORE FALLING THROUGH THE DAY. HIGHS ON TUESDAY WILL REACH ONLY THE MID/UPR 60S...AGAIN...EARLY IN THE DAY...AND THEN FALL INTO THE LOW 60S/UPR 50S BY EVE. THIS COMBINES WITH STRONG NE WINDS WHICH MAY GUST TO 30 MPH...AND TUESDAY WILL FEEL MORE LIKE NOVEMBER IN SEATTLE THAN OCTOBER IN WILMINGTON! LOWS TUESDAY NIGHT WILL SHOW VERY LITTLE DIURNAL RANGE...DROPPING ONLY INTO THE MID 50S INLAND...AROUND 60 AT THE COAST. LITTLE IMPROVEMENT WEDNESDAY...BUT ANY IMPROVEMENT WILL BE WELCOMED AFTER TUESDAY! CLOUDS AND RAIN PERSISTING WILL AGAIN LIMIT WARMING IN THE WEDGE SETUP...AND HIGHS WILL PEAK IN THE UPR 60S INLAND...LOW 70S NEAR THE COAST. LOWS WED NIGHT WILL BE SIMILAR TO TUESDAY NIGHT...UPR 50S TO LOW 60S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...ONE MORE UNSETTLED DAY THURSDAY AS VERY SLOW MOVING UPPER LOW AND SURFACE WAVE WILL FINALLY MOVE OFF TO THE NORTHEAST AND ALLOW FOR DRYING ACROSS THE AREA. GUIDANCE IN DISAGREEMENT AS TO HOW LONG IT WILL TAKE FOR DRYING TO OCCUR...BUT WITH UPPER LOW EMBEDDED WITHIN THE 5H RIDGE...THUS MOVING VERY SLOWLY...WILL LEAN ON THE SLOWER SOLUTION AND KEEP SCHC POP ACROSS NE ZONES EARLY THURSDAY BEFORE THE ENTIRE AREA DRIES OUT. BEYOND THURSDAY...HEIGHTS GRADUALLY RISE AND THE WEDGE SLOWLY BREAKS DOWN...ALLOWING FOR MUCH MORE SUNSHINE AND TEMPS WARMING BACK TOWARDS CLIMO OR ABOVE BY THE WKND. GFS/EURO/CMC STILL DEPICT A SECONDARY AREA OF LOW PRESSURE DEVELOPING WELL OFFSHORE AND THEN RETROGRADING BACK TO THE SW SAT/SUN TOWARDS THE COAST. WHILE THIS HAS BEEN A PERSISTENT FEATURE IN THE EXTENDED GUIDANCE...LITTLE AGREEMENT IN SPECIFIC PLACEMENT AND WHETHER ANY IMPACTS WILL BE FELT LOCALLY. WILL KEEP INHERITED SILENT POP FOR D6/D7 WITH TEMPS RIGHT AROUND NORMAL FOR MID-OCTOBER. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 12Z...SHOWERS CURRENTLY AFFECTING KFLO/KLBT WITH SUB-VFR FLIGHT CONDITIONS WILL GRADUALLY SPREAD EAST INTO THE COASTAL TERMINALS TODAY. THIS MORNING INTO THE AFTERNOON MVFR WILL BE LIKELY AT KFLO/KLBT...WITH TEMPO IFR IN MODERATE RAINFALL. THIS MORNING COASTAL TERMINALS SHOULD REMAIN GENERALLY VFR WITH TEMPO MVFR CIGS...WITH MVFR BECOMING MORE LIKELY TOWARDS LATE MORNING AS THE SHOWERS SHIFT EAST. AN APPROACHING COLD FRONT WILL PROVIDE ENOUGH LIFT TODAY ALONG WITH ENOUGH INSTABILITY TO PRODUCE AT LEAST ISOLATED T-STORMS. WILL CONTINUE VCTS FOR ALL TERMS DURING THE DAYTIME. SOUTHERLY FLOW WILL PERSIST FOR MUCH OF THE DAY WITH WINDS AROUND 10 KTS. THE FRONT WILL PASS THROUGH KFLO/KLBT AROUND 00Z TUESDAY...WITH WINDS BECOMING NORTHEAST AROUND 5 KTS FOLLOWING FROPA. BY 06Z TUESDAY...THE FRONT SHOULD BE NEAR THE COAST OR JUST OFFSHORE. WILL HOLD ONTO VCSH AT ALL TERMS THROUGH THE END OF THE TAF PERIOD AS DEEP MOISTURE LINGERS OVER OUR AREA. THERE IS INCREASING CONFIDENCE OF PREDOMINATE IFR AT KFLO/KLBT AFTER 06Z. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS AND ISOLATED SHOWERS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 730 AM MONDAY...SEAS HAVE BUILT TO 5 FT AT ALL THREE BUOYS STILL REPORTING IN THE CAPE FEAR AREA. WIND SPEEDS ARE ABOUT AS STRONG AS THEY ARE GOING TO GET...17 TO 20 KNOTS CURRENTLY...AND A DIMINISHING TREND IS STILL EXPECTED TO DEVELOP THIS AFTERNOON. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS... A NORTH-TO-SOUTH ORIENTED COLD FRONT JUST ENTERING THE APPALACHIANS WILL MOVE EASTWARD TODAY...DECELERATING AS IT APPROACHES THE COAST TONIGHT. SOUTH-SOUTHEAST WINDS 15-20 KNOTS THIS MORNING SHOULD DIMINISH THIS AFTERNOON. LOW PRESSURE DEVELOPING ALONG THE FRONT NEAR THE FLORIDA PANHANDLE WILL BECOME OUR DOMINANT WEATHER FEATURE TONIGHT. THE INCREASING PRESSURE GRADIENT BETWEEN THIS LOW AND STRENGTHENING HIGH PRESSURE OVER PENNSYLVANIA WILL LEAD TO INCREASING WIND SPEEDS LATE TONIGHT. A SURGE IS EXPECTED TO DEVELOP A FEW HOURS BEFORE DAYBREAK...WITH WINDS TURNING NORTH-NORTHEAST AND INCREASING TO 15-20 KT. SEAS CURRENTLY RANGE FROM 5 FT OUT AT THE FRYING PAN SHOALS BUOY...TO 3-4 FT CLOSER TO SHORE. STEADY ONSHORE WINDS THIS MORNING SHOULD BRING 5-FOOTERS INTO THE 10-20 MILE WATERS...AND AN EXERCISE CAUTION HEADLINE WILL BE APPENDED TO THE FORECAST THROUGH EARLY AFTERNOON. DIMINISHING WINDS THIS AFTERNOON WILL ALLOW SEAS TO SUBSIDE...BUT LOOK FOR BUILDING SEAS AGAIN VERY LATE TONIGHT IN THE NORTHERLY SURGE. SHOWERS AND THUNDERSTORMS CURRENTLY ACROSS EASTERN SOUTH CAROLINA WILL IMPACT THE SC COASTAL WATERS THIS MORNING. GUSTY WINDS AND REDUCED VISIBILITY IN HEAVY RAINFALL ARE EXPECTED. THIS ACTIVITY WILL MOVE EAST AND AFFECT THE NC WATERS THIS AFTERNOON. PRECIPITATION SHOULD BECOME LESS THUNDERY TONIGHT BUT SHOULD OTHERWISE CONTINUE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...STRONG NE WINDS WILL PERSIST THROUGH THE PERIOD AS THREE FEATURES COMBINE TO CREATE POOR MARINE CONDITIONS INTO MID-WEEK. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG A COLD FRONT STALLED JUST OFFSHORE...ENHANCING THE ALREADY PINCHED GRADIENT DUE TO A WEDGE OF HIGH PRESSURE FORMING DOWN THE COAST. THIS CREATES GUSTY NE WINDS TUESDAY AND WEDNESDAY...WITH SPEEDS OF 15-25 KTS TUESDAY...DROPPING SLIGHTLY TO 15-20 KTS ON WEDNESDAY. GUSTS TO 30 KTS ARE POSSIBLE...ESPECIALLY ON TUESDAY. THIS CREATES SHORT-PERIOD AND STEEP WIND WAVES REACHING 4-7 FT TUESDAY...BEFORE FALLING SLOWLY TO 3-5 FT BY WEDNESDAY EVE. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR ALL OF TUESDAY AND PARTS OF WEDNESDAY BEFORE CONDITIONS SLOWLY BEGIN TO IMPROVE LATE IN THE PERIOD. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...GUSTY N/NE WINDS TO START THE PERIOD WILL GRADUALLY EASE BY THE END OF THE WEEK AS HIGH PRESSURE WEDGE BEGINS TO BREAK DOWN JUST INLAND FROM THE WATERS. TIGHT GRADIENT THURSDAY KEEPS N/NE WINDS AT 15-20 KTS...BUT THIS WILL WEAKEN ON FRIDAY...HELPING WINDS TO FALL TO AROUND 10 KTS AND BACK MORE TO THE NORTH. WAVE HEIGHTS INITIALLY WILL BE 3-5 FT AND A SCEC MAY BE REQUIRED...BUT THESE WILL FALL QUICKLY ON FRIDAY TO 2-3 FT THANKS TO THE DECREASED WINDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...TRA SHORT TERM...JDW LONG TERM...JDW AVIATION...MRR MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
333 AM EDT MON OCT 7 2013 .SYNOPSIS... WIDESPREAD SHOWERS AND THUNDERSTORMS WILL OCCUR TODAY AHEAD OF A STRONG COLD FRONT WHICH WILL CROSS LATE TONIGHT. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG THIS FRONT AND MOVE NEAR THE AREA TUESDAY AND WEDNESDAY...PRODUCING WIDESPREAD RAIN AND MUCH COOLER TEMPERATURES. A DRYING AND WARMING TREND WILL BEGIN LATE IN THE WEEK AS HIGH PRESSURE BUILDS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM MONDAY...A STREAM OF SHOWERS ORIGINATING FROM THE GULF STREAM WATERS OFF THE GA/FL COAST CONTINUES TO MOVE NORTH INTO EASTERN SC EARLY THIS MORNING. SYNOPTIC MODELS 24 HOURS AGO WERE NOT ABLE TO CAPTURE THIS FEATURE...BUT RECENT HIGH-RESOLUTION MODELS LIKE THE HRRR AND NSSL WRF SEE IT WELL AND INDICATE THE "STREAMER" WILL CONTINUE THROUGH THE MORNING HOURS WITH SIGNIFICANT RAINFALL TOTALS POSSIBLE ACROSS EASTERN SOUTH CAROLINA. STRONG UPPER LEVEL LOW PRESSURE ACROSS THE SOUTHERN GREAT LAKES IS THE SAME SYSTEM RESPONSIBLE FOR THE RECORD-BREAKING EARLY SNOW ACROSS WESTERN SOUTH DAKOTA A COUPLE DAYS AGO. THIS UPPER SYSTEM WILL LIFT NORTHEAST...WHILE A VORTICITY MAXIMUM AT THE BASE OF THE UPPER TROUGH ALONG THE GULF COAST SLOWS AND BEGINS TO FORM A CLOSED LOW LATE TONIGHT. THE SURFACE PATTERN MIRRORS THE 500 MB CHART WITH AN EASTWARD-MOVING COLD FRONT LOCATED JUST AHEAD OF THE UPPER TROUGH. THIS FRONT WILL SLOW ITS PROGRESS AS SURFACE LOW PRESSURES DEVELOPS IN IN THE FLORIDA PANHANDLE. SHOWER AND T-STORM CHANCES ARE VERY HIGH TODAY...PROBABLY AT LEAST 90 PERCENT COVERAGE ACROSS THE EASTERN CAROLINAS. THIS MORNING`S HEAVY BAND OF SHOWERS ACROSS EASTERN SOUTH CAROLINA SHOULD SOAK THE PEE DEE AND INTERSTATE 95 CORRIDOR THROUGH MID-MORNING...SHIFTING EAST FROM MYRTLE BEACH THROUGH WHITEVILLE AND ELIZABETHTOWN BY NOON...THEN FINALLY REACHING THE CAPE FEAR AREA INCLUDING WILMINGTON BY THE MID-AFTERNOON HOURS. FROM A BROAD-SCALE PERSPECTIVE MANY AREAS SHOULD SEE TWO-THIRDS TO ONE INCH OF RAIN TODAY...BUT WITH TRAINING CONVECTION UNDOUBTEDLY A FEW SPOTS WILL RECEIVE 2-3 INCHES OR MORE. SEVERE WEATHER POTENTIAL IS NOT ZERO...BUT IS LESS THAN EXPECTED YESTERDAY DUE TO WEAKENING LOW-LEVEL WIND FIELDS AND OVERALL MODEST INSTABILITY. IN FACT IT APPEARS ISOLATED FLOODING MAY BECOME A LARGER FACTOR TO CONTEND WITH THAN SEVERE WEATHER. SHOULD A THUNDERSTORM BECOME SEVERE TODAY...WET MICROBURSTS APPEAR TO BE THE MOST SIGNIFICANT THREAT. TONIGHT THE PRESSURE GRADIENT BETWEEN THE LOW OVER NORTHERN FLORIDA AND HIGH PRESSURE STRENGTHENING OVER PENNSYLVANIA SHOULD PRODUCE A NORTHERLY SURGE THAT WILL REACH OUR AREA A FEW HOURS BEFORE SUNRISE. THIS SHALLOW COLD AIRMASS WILL UNDERCUT THE OTHERWISE WARM AND HUMID AIR PRESENT...PRODUCING GUSTY WINDS AND SUDDENLY FALLING TEMPERATURES. PRECIPITATION CHANCES WILL CONTINUE AS WELL... ESPECIALLY ALONG THE COAST...BUT ISENTROPIC PROCESSES WILL BECOME MORE DOMINANT WITH TIME AS INSTABILITY WANES AND VEERING LOW LEVEL WINDS ADVECT ATLANTIC MOISTURE BACK ONSHORE. POPS TONIGHT RANGE FROM 80 PERCENT ALONG THE COAST TO 60 PERCENT IN FLORENCE AND DARLINGTON. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...SLOW MOVING UPPER LOW WILL EJECT OUT OF THE GULF OF MEXICO AND DRIFT NORTHEAST THROUGH THE PERIOD...SPAWNING A WAVE OF LOW PRESSURE ALONG A COLD FRONT STALLED ON THE COAST. STRONG VORT MAX ACROSS SOUTHEAST TEXAS WILL MOVE INTO THE GULF AND THEN DRIFT NORTHEAST OVERHEAD THE CAROLINAS TUESDAY AND WEDNESDAY. THIS SPAWNS A SURFACE WAVE ALONG A COLD FRONT WHICH WILL BE STALLED RIGHT ON THE COAST...AND WILL KEEP UNSETTLED WEATHER THROUGH THE PERIOD. GUIDANCE IS IN GOOD AGREEMENT THAT BOTH TUESDAY AND WEDNESDAY WILL BE WET...A SIGNIFICANT CHANGE FROM MODELS LAST NIGHT. AS THE FRONT STALLS JUST OFFSHORE...ABUNDANT TROPICAL MOISTURE REMAINS IN PLACE. THIS SERVES AS THE FUEL FOR PERIODS OF MDT/HVY RAIN TUE AND WED AS THE UPPER LOW MOVES OVERHEAD. ADDITIONALLY...ISENTROPIC LIFT OVER THE DEVELOPING WEDGE-HIGH PRESSURE WILL ENHANCE RAINFALL...ESPECIALLY ACROSS EASTERN PORTIONS OF THE CWA. WPC IS SHOWING WIDESPREAD 1-2 INCHES OF QPF...MOST ACROSS THE CAPE FEAR REGION TUE/WED. THIS MAY BE A BIT HIGH...BUT CERTAINLY SHOWS THE POTENTIAL WITHIN THE TROPICAL MOISTURE PLUME. IN ADDITION TO THE UNSETTLED WEATHER...TEMPS WILL BE WELL BELOW NORMAL BOTH TUE AND WED THANKS TO THE WEDGE HIGH PRESSURE AND CLOUDS/RAIN. STRONG LOW LVL CAA DEVELOPS EARLY TUESDAY...AND HAVE SHOWN AN ATYPICAL DIURNAL CURVE WITH MAX TEMPS BEING REACHED FIRST THING TUESDAY MORNING...BEFORE FALLING THROUGH THE DAY. HIGHS ON TUESDAY WILL REACH ONLY THE MID/UPR 60S...AGAIN...EARLY IN THE DAY...AND THEN FALL INTO THE LOW 60S/UPR 50S BY EVE. THIS COMBINES WITH STRONG NE WINDS WHICH MAY GUST TO 30 MPH...AND TUESDAY WILL FEEL MORE LIKE NOVEMBER IN SEATTLE THAN OCTOBER IN WILMINGTON! LOWS TUESDAY NIGHT WILL SHOW VERY LITTLE DIURNAL RANGE...DROPPING ONLY INTO THE MID 50S INLAND...AROUND 60 AT THE COAST. LITTLE IMPROVEMENT WEDNESDAY...BUT ANY IMPROVEMENT WILL BE WELCOMED AFTER TUESDAY! CLOUDS AND RAIN PERSISTING WILL AGAIN LIMIT WARMING IN THE WEDGE SETUP...AND HIGHS WILL PEAK IN THE UPR 60S INLAND...LOW 70S NEAR THE COAST. LOWS WED NIGHT WILL BE SIMILAR TO TUESDAY NIGHT...UPR 50S TO LOW 60S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...ONE MORE UNSETTLED DAY THURSDAY AS VERY SLOW MOVING UPPER LOW AND SURFACE WAVE WILL FINALLY MOVE OFF TO THE NORTHEAST AND ALLOW FOR DRYING ACROSS THE AREA. GUIDANCE IN DISAGREEMENT AS TO HOW LONG IT WILL TAKE FOR DRYING TO OCCUR...BUT WITH UPPER LOW EMBEDDED WITHIN THE 5H RIDGE...THUS MOVING VERY SLOWLY...WILL LEAN ON THE SLOWER SOLUTION AND KEEP SCHC POP ACROSS NE ZONES EARLY THURSDAY BEFORE THE ENTIRE AREA DRIES OUT. BEYOND THURSDAY...HEIGHTS GRADUALLY RISE AND THE WEDGE SLOWLY BREAKS DOWN...ALLOWING FOR MUCH MORE SUNSHINE AND TEMPS WARMING BACK TOWARDS CLIMO OR ABOVE BY THE WKND. GFS/EURO/CMC STILL DEPICT A SECONDARY AREA OF LOW PRESSURE DEVELOPING WELL OFFSHORE AND THEN RETROGRADING BACK TO THE SW SAT/SUN TOWARDS THE COAST. WHILE THIS HAS BEEN A PERSISTENT FEATURE IN THE EXTENDED GUIDANCE...LITTLE AGREEMENT IN SPECIFIC PLACEMENT AND WHETHER ANY IMPACTS WILL BE FELT LOCALLY. WILL KEEP INHERITED SILENT POP FOR D6/D7 WITH TEMPS RIGHT AROUND NORMAL FOR MID-OCTOBER. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... AS OF 06Z...BAND OF SHOWERS EMANATING FROM THE ATLANTIC OCEAN NEAR CHARLESTON WILL AFFECT FLORENCE AND LUMBERTON EARLY THIS MORNING. THE BIGGEST THREAT WILL BE TRANSIENT LOW CEILINGS NEAR MODERATE RAINFALL. AT FLORENCE THERE IS A MODERATE CHANCE OF SUB-1000 FOOT CEILINGS THROUGH 09Z...WITH LOW PROBABILITIES OF IFR CIGS THROUGH DAYBREAK. AT LUMBERTON IFR PROBABILITIES ARE LOWER BUT CANNOT TOTALLY BE RULED OUT. FOR THE COASTAL AIRPORTS (ILM, MYR, CRE) THE BULK OF THE SHOWER ACTIVITY OVER THE NEXT 6 HOURS SHOULD REMAIN TO THE WEST...WITH GENERALLY VFR TO OCCASIONAL MVFR CONDITIONS EXPECTED. AN APPROACHING COLD FRONT WILL BRING SHRA TO OUR FORECAST AREA LATER TODAY. VFR/MVFR CONDITIONS SHOULD PREVAIL...WITH TEMPO PERIODS OF IFR VSBYS IN HEAVIER SHOWERS. FCST SOUNDINGS SUGGEST THERE WILL BE ENOUGH INSTABILITY FOR AT LEAST ISOLATED T-STORMS...SO HAVE INCLUDED VCTS FOR ALL TERMS DURING THE DAYTIME. SOUTHERLY FLOW WILL PERSIST FOR MUCH OF THE DAY WITH WINDS AROUND 10 KTS. THE FRONT WILL PASS THROUGH KFLO/KLBT AROUND 00Z TUESDAY...WITH WINDS BECOMING NORTHEAST AROUND 5 KTS FOLLOWING FROPA. BY 06Z TUESDAY...THE FRONT SHOULD BE NEAR THE COAST OR JUST OFFSHORE. WILL HOLD ONTO VCSH AT ALL TERMS THROUGH THE END OF THE TAF PERIOD AS DEEP MOISTURE LINGERS OVER OUR AREA. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS AND ISOLATED SHOWERS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM MONDAY...A NORTH-TO-SOUTH ORIENTED COLD FRONT JUST ENTERING THE APPALACHIANS WILL MOVE EASTWARD TODAY...DECELERATING AS IT APPROACHES THE COAST TONIGHT. SOUTH-SOUTHEAST WINDS 15-20 KNOTS THIS MORNING SHOULD DIMINISH THIS AFTERNOON. LOW PRESSURE DEVELOPING ALONG THE FRONT NEAR THE FLORIDA PANHANDLE WILL BECOME OUR DOMINANT WEATHER FEATURE TONIGHT. THE INCREASING PRESSURE GRADIENT BETWEEN THIS LOW AND STRENGTHENING HIGH PRESSURE OVER PENNSYLVANIA WILL LEAD TO INCREASING WIND SPEEDS LATE TONIGHT. A SURGE IS EXPECTED TO DEVELOP A FEW HOURS BEFORE DAYBREAK...WITH WINDS TURNING NORTH-NORTHEAST AND INCREASING TO 15-20 KT. SEAS CURRENTLY RANGE FROM 5 FT OUT AT THE FRYING PAN SHOALS BUOY...TO 3-4 FT CLOSER TO SHORE. STEADY ONSHORE WINDS THIS MORNING SHOULD BRING 5-FOOTERS INTO THE 10-20 MILE WATERS...AND AN EXERCISE CAUTION HEADLINE WILL BE APPENDED TO THE FORECAST THROUGH EARLY AFTERNOON. DIMINISHING WINDS THIS AFTERNOON WILL ALLOW SEAS TO SUBSIDE...BUT LOOK FOR BUILDING SEAS AGAIN VERY LATE TONIGHT IN THE NORTHERLY SURGE. SHOWERS AND THUNDERSTORMS CURRENTLY ACROSS EASTERN SOUTH CAROLINA WILL IMPACT THE SC COASTAL WATERS THIS MORNING. GUSTY WINDS AND REDUCED VISIBILITY IN HEAVY RAINFALL ARE EXPECTED. THIS ACTIVITY WILL MOVE EAST AND AFFECT THE NC WATERS THIS AFTERNOON. PRECIPITATION SHOULD BECOME LESS THUNDERY TONIGHT BUT SHOULD OTHERWISE CONTINUE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...STRONG NE WINDS WILL PERSIST THROUGH THE PERIOD AS THREE FEATURES COMBINE TO CREATE POOR MARINE CONDITIONS INTO MID-WEEK. A WAVE OF LOW PRESSURE WILL DEVELOP ALONG A COLD FRONT STALLED JUST OFFSHORE...ENHANCING THE ALREADY PINCHED GRADIENT DUE TO A WEDGE OF HIGH PRESSURE FORMING DOWN THE COAST. THIS CREATES GUSTY NE WINDS TUESDAY AND WEDNESDAY...WITH SPEEDS OF 15-25 KTS TUESDAY...DROPPING SLIGHTLY TO 15-20 KTS ON WEDNESDAY. GUSTS TO 30 KTS ARE POSSIBLE...ESPECIALLY ON TUESDAY. THIS CREATES SHORT-PERIOD AND STEEP WIND WAVES REACHING 4-7 FT TUESDAY...BEFORE FALLING SLOWLY TO 3-5 FT BY WEDNESDAY EVE. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR ALL OF TUESDAY AND PARTS OF WEDNESDAY BEFORE CONDITIONS SLOWLY BEGIN TO IMPROVE LATE IN THE PERIOD. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...GUSTY N/NE WINDS TO START THE PERIOD WILL GRADUALLY EASE BY THE END OF THE WEEK AS HIGH PRESSURE WEDGE BEGINS TO BREAK DOWN JUST INLAND FROM THE WATERS. TIGHT GRADIENT THURSDAY KEEPS N/NE WINDS AT 15-20 KTS...BUT THIS WILL WEAKEN ON FRIDAY...HELPING WINDS TO FALL TO AROUND 10 KTS AND BACK MORE TO THE NORTH. WAVE HEIGHTS INITIALLY WILL BE 3-5 FT AND A SCEC MAY BE REQUIRED...BUT THESE WILL FALL QUICKLY ON FRIDAY TO 2-3 FT THANKS TO THE DECREASED WINDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...TRA SHORT TERM...JDW LONG TERM...JDW AVIATION...TRA MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
130 AM EDT MON OCT 7 2013 .SYNOPSIS... A FEW SHOWERS WILL CONTINUE THIS AFTERNOON AND TONIGHT. A STRONG COLD FRONT WILL CROSS THE CAROLINAS LATE MONDAY...BRINGING A PERIOD OF SHOWERS AND THUNDERSTORMS. MOISTURE AND BLUSTERY CONDITIONS WILL CONTINUE TUESDAY AND WEDNESDAY. A DRYING TREND SHOULD DEVELOP LATER IN THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 130 AM MONDAY...AN EARLY MORNING UPDATE HAS BEEN MADE TO RAISE POPS ACROSS THE SC PEE DEE REGION INTO THE LIKELY (60-70 PERCENT) RANGE. SHOWERS ADVECTING NORTHWARD FROM THE CHARLESTON VICINITY WILL MOVE OVERHEAD FOR THE NEXT SEVERAL HOURS. ALSO MADE LARGE INCREASES TO FORECAST SKY COVER. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS... STREAMER TYPE CONVECTION FROM OFF THE ATL WATERS TO CONTINUE OVERNIGHT. SPEED CONVERGENCE IN THE LOWER LEVELS AS A RESULT OF THE SE-S ONSHORE FLOW CONTINUES TO FIRE LOW TOPPED CONVECTION ACROSS THE ILM COASTAL WATERS AND ONSHORE. WITH THE DAYS INSOLATION OVERWITH...THE ACTIVITY THAT MOVES ONSHORE WILL FOR THE MOST PART BE UNABLE TO SUSTAIN ITS INTENSITY LET ALONE ITS INTEGRITY AS IT PROGRESSES FURTHER INLAND. THIS CURRENTLY IS BEING PLAYED OUT AS ONE LOOPS THE KLTX AND SURROUNDING RADARS. ALTHOUGH CURRENT LTG REMAINS LACKING...THE ACTIVITY OVER THE ADJACENT ATL WATERS WILL HAVE INCREASING AND DEEPER INSTABILITY OVERNIGHT AS ACTIVITY PASSES OVER SSTS THAT ARE AROUND 80 DEGREES. WOULD NOT BE SURPRISED FOR THUNDER TO OCCUR...AND POSSIBLY REACH AND PUSH ONSHORE LATER OVERNIGHT. NO PRONOUNCED UPPER S/W TROF OR VORT TO AFFECT THE FA OVERNITE THAT WOULD PROVIDE ADDITIONAL FORCING TO FURTHER PROMOTE THUNDER. THIS IS NOT PROGGED BY THE MODELS TO OCCUR UNTIL DAYTIME MONDAY WHILE APPROACHING FROM THE WEST. HOWEVER...ENOUGH CAPE MANIFESTS ACROSS THE FA TOWARD DAYBREAK MONDAY AS EXHIBITED BY THE LATEST HRRR MODEL RUN...TO AT-LEAST MENTION ISOLATED THUNDER DURING THIS TIME FRAME. OVERALL...POPS ACROSS THE FA OVERNIGHT WILL RANGE BETWEEN 25 TO 50 PERCENT. WIDESPREAD 70+ SFC DEWPOINTS CURRENTLY ACROSS THE FA. DO NOT SEE MUCH OF A DOWNWARD OR DECREASING TREND OVERNITE WITH SFC DEWPOINTS. AS A RESULT...LOOKING AT WIDESPREAD 70 TO 75 DEGREE LOWS FOR TONIGHT...WHICH IS NEARLY 15 DEGREES HIGHER THAN CLIMO NORMS FOR THIS TIME OF THE YEAR. MUST BE GLOBAL WARMING AGAIN. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE SHORT TERM CONTINUES TO TREND TO A VERY ACTIVE PERIOD MOSTLY AS A RESULT OF MODEL CONSENSUS ON THE EVENTS FOR TUESDAY. THE 1200 UTC GFS AND NAM ARE IN AGREEMENT ON A MID LEVEL LOW CUTTING OFF IN THE SOUTHEAST TUESDAY WITH BROAD ISENTROPIC LIFT DEVELOPING BETWEEN STRONG HIGH PRESSURE TO THE NORTH AND THE ASSOCIATED SURFACE LOW/TROUGH TO THE SOUTH. IT WILL BE A RATHER WET AND RAW DAY AS GUIDANCE SHOWS HIGH TEMPERATURES REMAINING IN THE 60S WITH WIND SPEEDS FROM THE EAST/NORTHEAST AT 10-15 MPH. THE LACK OF SATURATION IN THE 305K LAYER AND MODEST ISENTROPIC LIFT...WINDS ARE ACTUALLY FAIRLY LIGHT ABOVE THE SURFACE MAY KEEP QPF VALUES MODEST. HOWEVER SUBSEQUENT SHIFTS MAY WANT TO INCREASE POPS ESPECIALLY LATE IN THE PERIOD AS THE COLUMN SHOWS BETTER SATURATION IN THIS LAYER. AS FOR THE EVENTS MONDAY...LITTLE CHANGE WAS WARRANTED WITH THE FORECAST AS THE MODELS ARE STILL IN AGREEMENT ON THE FRONT...CURRENTLY LOCATED IN THE TENNESSEE VALLEY MOVING ACROSS MONDAY EVENING. MAINTAINED THE LIKELY TO CATEGORICAL POPS WITH THE SAME TEMPORAL TRENDS. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...WEDNESDAY NO LONGER LOOKING DRY AS PREVIOUSLY THOUGHT. A WEAK SOUTHERN BRANCH SHORTWAVE LIFTS OUT OF THE GULF OF MEXICO EARLY IN THE WEEK AND CROSSES THE CAROLINAS WEDNESDAY. THERE IS STILL COPIOUS/DEEP MOISTURE IN PLACE AS THE THE MONDAY COLD FRONT ONLY SEEMS TO REMOVE THE SURFACE MOISTURE. THE UPPER SYSTEM INDUCES A WAVE ALONG THE BOUNDARY WELL OFFSHORE ON WEDNESDAY BUT ITS LOCATION IS NOT AGREED UPON BY VARIOUS GUIDANCE. INTERESTINGLY THE EC DOESN`T REALLY DEVELOP A WAVE BUT STILL HAS QPF AS THE UPPER SHORTWAVE MOVES ATOP THE WEDGE. WILL INTRODUCE LOW CHC POPS MAINLY ALONG THE COAST. MOST IF NOT ALL OF THE REMAINDER OF THE PERIOD WILL BRING DRY WEATHER AS BUILDING UPPER LEVEL RIDGE AND SOUTHWARD SPRAWLING SURFACE HIGH OCCUPY OUR LONGITUDE. THE GFS CONTINUES TO SHOW THAT OUR WEDNESDAY SHORTWAVE EVENTUALLY BEARS A LOW OFF THE DELMARVA COAST THAT RETROGRADES AND MAY BRING SOME WEEKEND POPS. FOR NOW THIS LOOKS JUST ANOMALOUS ENOUGH TO CAP POPS AT SLIGHT. THE EC ALSO SHOWS SOME ATLANTIC DEVELOPMENT BUT NOT THE RETROGRADING MOTION. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...BAND OF SHOWERS EMANATING FROM THE ATLANTIC OCEAN NEAR CHARLESTON WILL AFFECT FLORENCE AND LUMBERTON EARLY THIS MORNING. THE BIGGEST THREAT WILL BE TRANSIENT LOW CEILINGS NEAR MODERATE RAINFALL. AT FLORENCE THERE IS A MODERATE CHANCE OF SUB-1000 FOOT CEILINGS THROUGH 09Z...WITH LOW PROBABILITIES OF IFR CIGS THROUGH DAYBREAK. AT LUMBERTON IFR PROBABILITIES ARE LOWER BUT CANNOT TOTALLY BE RULED OUT. FOR THE COASTAL AIRPORTS (ILM, MYR, CRE) THE BULK OF THE SHOWER ACTIVITY OVER THE NEXT 6 HOURS SHOULD REMAIN TO THE WEST...WITH GENERALLY VFR TO OCCASIONAL MVFR CONDITIONS EXPECTED. AN APPROACHING COLD FRONT WILL BRING SHRA TO OUR FORECAST AREA LATER TODAY. VFR/MVFR CONDITIONS SHOULD PREVAIL...WITH TEMPO PERIODS OF IFR VSBYS IN HEAVIER SHOWERS. FCST SOUNDINGS SUGGEST THERE WILL BE ENOUGH INSTABILITY FOR AT LEAST ISOLATED T-STORMS...SO HAVE INCLUDED VCTS FOR ALL TERMS DURING THE DAYTIME. SOUTHERLY FLOW WILL PERSIST FOR MUCH OF THE DAY WITH WINDS AROUND 10 KTS. THE FRONT WILL PASS THROUGH KFLO/KLBT AROUND 00Z TUESDAY...WITH WINDS BECOMING NORTHEAST AROUND 5 KTS FOLLOWING FROPA. BY 06Z TUESDAY...THE FRONT SHOULD BE NEAR THE COAST OR JUST OFFSHORE. WILL HOLD ONTO VCSH AT ALL TERMS THROUGH THE END OF THE TAF PERIOD AS DEEP MOISTURE LINGERS OVER OUR AREA. EXTENDED OUTLOOK...SCATTERED SHOWERS WITH MVFR CIGS ON TUESDAY AS THE FRONT LINGERS OFFSHORE. MVFR/IFR CIGS AND ISOLATED SHOWERS POSSIBLE ON WEDNESDAY MORNING...BECOMING VFR THURSDAY AND FRIDAY.&& .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM MONDAY...NO SIGNIFICANT CHANGES NECESSARY. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS... LATEST PIER AND BUOY OBS ACROSS THE AREA WATERS INDICATE WINDS ARE RUNNING CLOSE TO THE CURRENT FORECAST TREND. WILL ONLY MAKE SLIGHT ADJUSTMENTS TO WIND DIRECTIONS...WITH SE-S BEING ADVERTISED INSTEAD OF INDICATING A SSE WIND DIRECTION. LATEST HRRR SFC WIND OUTPUT ACROSS THE ILM WATERS CONTINUES WITH 10-15 KT...INCREASING TO 15-20 KT BY DAYBREAK. THIS ONSHORE FLOW WILL BUILD SIGNIFICANT SEAS RATHER QUICKLY OVERNIGHT...WITH THE MAJORITY OF THE ILM COASTAL WATERS AT 3 TO 5 FT BY DAYBREAK MONDAY. BUILDING WIND DRIVEN WAVES AT 4 TO 6 SECOND PERIODS WILL DOMINATE THE WAVE SPECTRUM OVERNIGHT. THE SMALL ESE 9 TO 11 SECOND PERIOD GROUND SWELL WILL PROVIDE NO AID FOR INCREASING THE SIG. SEAS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...THE MARINE COMMUNITY WILL SEE RATHER CHANGEABLE CONDITIONS THROUGH THE PERIOD. EXPECT A SOUTHEAST FLOW OF 15-20 KNOTS INITIALLY. THIS FLOW WILL WEAKEN AND VEER TO THE SOUTH THEN SOUTHWEST BY THE END OF THE DAY MONDAY. A FRONT WILL MOVE ACROSS THE WATERS AROUND 0600 UTC TUESDAY WITH A NORTH TO NORTHEASTERLY FLOW DEVELOPING BY 1200 TUESDAY. SPEEDS WILL INCREASE AS WELL TO 15-20 KNOTS BY THIS TIME. THIS PATTERN WILL REMAIN IN PLACE THROUGH THE END OF THE PERIOD. SIGNIFICANT SEAS ARE 3-5 FEET EARLY IN THE PERIOD WITH A DECREASE MONDAY EVENING. SEAS WILL INCREASE ONCE AGAIN TUESDAY ESPECIALLY LATER IN THE DAY TO POSSIBLY SMALL CRAFT CRITERIA. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...LONG DURATION OF NORTHERLY FLOW EXPECTED. HIGH PRESSURE WEDGING IN EAST OF THE APPALACHIANS TO PRODUCE A MODERATE GRADIENT ACROSS THE WATERS. A WAVE OF LOW PRESSURE SHOULD DEVELOP SOMEWHERE ALONG COLD FRONT STALLED WELL OFFSHORE BUT ITS LOCATION IS UNCERTAIN AT THIS POINT. THIS IS EXPECTED TO MODULATE THE STRENGTH OF THE GRADIENT AND HAVE AN IMPACT ON THE STRENGTH OF THE GRADIENT PINCH AND WHETHER OR NOT WELL NEED ANY HEADLINES OR EVEN BORDERLINE AND SHORT-LIVED ADVISORY OUT ALONG FRYING PAN SHOALS. WHEREVER THIS LOW DEVELOPS...IT WILL PULL AWAY TO THE NORTH AND EAST THURSDAY INTO FRIDAY AND THE SURFACE HIGH WILL REMAIN ENTRENCHED ACROSS THE EASTERN U.S. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...DCH/TRA SHORT TERM...SHK LONG TERM...MBB AVIATION...BJR/TRA
AREA FORECAST DISCUSSION
NWS MEDFORD OR
825 PM PDT TUE OCT 8 2013 .DISCUSSION...UPDATES WERE ALREADY MADE THIS EVENING. A COLD, MOIST UPPER LOW CENTERED AROUND THE OR/WA BORDER THIS EVENING WILL SLIDE RIGHT THROUGH OUR AREA TONIGHT. COLD ADVECTION IS ALREADY IN PROGRESS AND SNOW LEVELS ARE FALLING. SNOW CAN BE SEEN NOW ON THE DOT CAMERA AT DIAMOND LAKE AND OBS SHOW TEMPERATURES DOWN INTO THE 30S ACROSS MUCH OF EAST SIDE OREGON ZONES ALREADY. WHILE THERE WILL BE SHOWERS OVER MANY AREAS EARLY TONIGHT, PRECIPITATION WILL BE FOCUSED EAST OF THE CASCADES OVERNIGHT, AND ESPECIALLY ACROSS SOUTHEAST LAKE COUNTY. IN FACT, THERE IS A BRIEF PERIOD OF MID LEVEL FRONTOGENESIS OVER SOUTHEAST LAKE COUNTY AND THIS IS FOLLOWED BY DEEP, MOIST UPSLOPE INTO THE MOUNTAINS THERE. AS A RESULT, THE 09/00Z NAM AND RUC SHOW SOMEWHERE BETWEEN 0.50 AND 0.75 INCH OF LIQUID IN THE AREA TONIGHT. SOME OF THIS WILL COME AS RAIN INITIALLY, BUT THERE SHOULD BE ENOUGH QPF AS COLD AIR ARRIVES IN BULK TO PRODUCE ADVISORY LEVEL SNOW. AS A RESULT, I ISSUED A WINTER WEATHER ADVISORY FOR THE WARNERS EAST OF LAKEVIEW OVER TO THE HART MOUNTAIN REFUGE TONIGHT. THIS WILL DECREASE BY AROUND DAWN WITH A COOL, BREEZY BUT DRY DAY TOMORROW. -WRIGHT && .AVIATION...BASED ON THE 09/00Z TAF CYCLE. A POTENT DISTURBANCE WILL MOVE THROUGH TONIGHT BRINGING -SHRA/-SHSN AND LOWERING FREEZING LEVELS...DOWN TO 4500 FEET OVERNIGHT. THIS WILL INCREASE THE LIKELIHOOD OF ICING. EXPECT A MIX OF VFR/MVFR CIGS ALONG WITH AT LEAST PARTIAL TERRAIN OBSCURATIONS. A PERIOD OF MODERATE SNOW MAY OCCUR FOR SEVERAL HOURS OVER THE FAR EAST SIDE IN THE VICINITY OF HART MOUNTAIN REFUGE AND THE WARNER MOUNTAINS. LOCAL IFR CIGS ARE EXPECTED TO DEVELOP IN THE UMPQUA BASIN AND ALONG AND NEAR THE COAST OVERNIGHT. EXPECT VFR ALL AREAS BY LATE WEDNESDAY MORNING. SPILDE && .PREV DISCUSSION... /ISSUED 256 PM PDT TUE OCT 8 2013/ SHORT TERM...AN UPPER LOW CENTERED OVER NORTHERN OREGON IS SHIFTING SOUTHWARD AND IS FORECAST TO MOVE INTO SOUTHEAST OREGON TONIGHT. SHOWERS ARE OCCURING JUST NORTH OF THE CWA AND ARE FORECAST TO SPREAD INTO NORTHERN PORTIONS OF THE CWA THIS AFTERNOON...THEN SPREAD ACROSS MUCH OF THE AREA THIS EVENING. SHOWERS WILL DIMINISH LATE TONIGHT AND WEDNESDAY MORNING AS THE LOW CONTINUES TO MOVE SOUTHWARD. BEHIND THIS LOW EXPECT THE EASTERN PORTION OF A PACIFIC RIDGE TO NUDGE INTO THE AREA WEDNESDAY AND THURSDAY BRINGING MAINLY DRY CONDITIONS. CURRENTLY...SHOWERS ARE OCCURING JUST NORTH OF THE CWA AND WILL SPREAD INTO COOS...DOUGLAS AND NORTHERN PORTIONS OF KLAMATH AND LAKE COUNTIES LATER THIS AFTERNOON. MODELS CONTINUE TO AGREE THAT SHOWER ACTIVITY WILL INCREASE DURING THE EVENING AS THE LOW MOVES INTO THE AREA BRINGING MOISTURE AND SOME INSTABILITY. ALSO A JET ALOFT WILL ALSO SUPPORT SHOWERS THIS EVENING. BEST SHOWER ACTIVITY IS EXPECTED OVER COOS AND DOUGLAS COUNTIES EASTWARD INTO THE SOUTHERN OREGON CASCADES AND EAST SIDE. HOWEVER ISOLATED TO SCATTERED SHOWERS MAY BE EXPECTED AS WELL FROM THE SISKIYOUS NORTH THIS EVENING IN SOUTHERN OREGON. ALSO THIS EVENING...COLD AIR ALOFT COMBINED WITH SOME WEAK INSTABILITY MAY BRING SOME LOCALLY HEAVIER SHOWERS AS WELL AS A SLIGHT CHANCE FOR THUNDERSTORMS TO LOCATIONS ALONG THE SOUTHERN OREGON CASCADES AND FOR AREAS EAST OF THE CASCADES IN OREGON AND NORTHERN CALIFORNIA. OVERNIGHT...THE SHOWERS ARE EXPECTED TO MOVE SOUTHWARD...LINGERING EAST OF THE CASCADES ESPECIALLY OVER SOUTHERN LAKE AND MODOC COUNTIES. SHOWER ACTIVITY WILL DIMINISH WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON FOR THESE AREAS AS THE LOW CONTINUES TO MOVES SOUTHWARD. LIGHT SNOW ACCUMULATIONS ARE POSSIBLE TONIGHT WITH THIS SYSTEM. SNOW LEVELS NEAR 5500 TO 6500 FEET ARE FORECAST TO LOWER TO 4500 TO 5500 FEET THEN EVENING THEN LOWER DOWN TO 4000 TO 5000 FEET TONIGHT. SNOW SHOWERS ARE EXPECTED TO BRING 1 TO 3 INCHES OF SNOW TO THE SOUTHERN OREGON CASCADES, MAINLY FROM CRATER LAKE NORTH, AND 1 TO 4 INCHES OF SNOW TO THE MOUNTAINS EAST OF THE CASCADES, ESPECIALLY IN THE HART MOUNTAIN AREA. ALSO EAST SIDE VALLEYS...SUCH AS NEAR LAKEVIEW AND ALTURAS...MAY SEE UP TO AN INCH OF SNOW TONIGHT. WEST OF THE CASCADES...EXPECT THE MAIN IMPACT TO BE COLD TEMPERATURES WEDNESDAY MORNING AND AGAIN ON THURSDAY MORNING. PARTIAL CLEARING IS EXPECTED WEST OF THE CASCADES EARLY WEDNESDAY MORNING AND COMBINED WITH THE COLD AIR MASS, THIS MAY BRING SOME PATCHY FROST TO WESTERN VALLEYS. THEN THURSDAY MORNING...THE FROST POTENTIAL WILL INCREASE DUE TO MAINLY CLEAR SKIES UNDER WEAK HIGH PRESSURE. GUIDANCE IS INDICATING TEMPERATURES IN THE MID TO UPPER 30S FOR WESTERN VALLEYS THURSDAY MORNING...ESPECIALLY IN THE ROGUE, ILLINOIS AND APPLEGATE VALLEYS. FURTHER SOUTH IN THE SHASTA AND SCOTT VALLEYS LOW TEMPERATURES NEAR FREEZING ARE POSSIBLE THURSDAY MORNING. OTHERWISE...DURING THE DAY WEDNESDAY MOST AREAS WILL SEE DRY AND COOL WEATHER. TEMPERATURES WILL WARM ON THURSDAY SEVERAL DEGREES WITH HIGHS APPROACHING NEAR SEASONAL NORMS. A VERY WEAK FRONT MOVES INTO THE COOS AND DOUGLAS COAST LATE THURSDAY BUT EXPECT LITTLE IF ANY PRECIPITATION FROM THIS FRONT. THEN ON FRIDAY...DRY WEATHER CONTINUES WITH RIDGING OVER THE AREA. BY FRIDAY NIGHT...ANOTHER SHORTWAVE AND FRONT MAY MOVE TOWARDS THE AREA. LONG TERM...SATURDAY, OCT 12TH THROUGH TUESDAY, OCT 15TH... ALTHOUGH THE GFS AND ECMWF OPERATIONAL MODEL GUIDANCE HAS MANY SIMILARITIES FOR THIS TIME PERIOD, THERE STILL REMAIN SIZABLE DIFFERENCES IN SENSIBLE WEATHER AS WE GET INTO THE WEEKEND THROUGH EARLY NEXT WEEK. ADDITIONALLY, MODEL ENSEMBLES INDICATE QUITE A BIT OF SPREAD THAT INCREASES SIGNIFICANTLY WITH TIME THIS WEEKEND INTO EARLY NEXT WEEK, SO THIS MEANS THAT UNCERTAINTY IN THE FORECAST ALSO INCREASES SUBSTANTIALLY THE FURTHER OUT WE GO IN THE FORECAST. THAT BEING SAID, EARLY IN THE FORECAST PERIOD WE REMAIN IN A GENERAL NORTHWEST FLOW PATTERN ON THE WESTERN SIDE OF A TROUGH DOWNSTREAM OF HIGH PRESSURE RIDGING IN THE GULF OF ALASKA. THE GFS INDICATES A WEAK SHORTWAVE TROUGH MOVING THROUGH ON FRIDAY, WHILE THE ECMWF, INSTEAD, DROPS A SOMEWHAT MORE SIGNIFICANT TROUGH INTO THE AREA SATURDAY INTO SUNDAY. THE RELATIVE MEASURE OF PREDICTABILITY WITH THIS TROUGH IS LOW PER NCEP GLOBAL ENSEMBLES. THIS MEANS THAT, IF THE GFS IS CORRECT, TEMPERATURES WILL BE NEAR NORMAL ACROSS THE AREA THIS WEEKEND, WITH HIGHS IN THE 50S AND 60S TO NEAR 70 ACROSS THE AREA. THE ECMWF SOLUTION, INSTEAD, WOULD INDICATE TEMPERATURES 5 TO 10 DEGREES LOWER DUE TO CLOUD COVER A CHANCE OF SHOWERS OVER NORTHWESTERN PORTIONS OF THE AREA. GIVEN THE PATTERN WE HAVE BEEN IN, I`VE LEANED HALFWAY TO THE EUROPEAN SOLUTION. REASONING NOT TO LEAN FURTHER IS THAT THE FOLKS BACK EAST AT NCEP INDICATE THAT THE ECMWF SOLUTION BEGINS TO LOSE FAVOR OVER THE WEEKEND AS THE OVERALL PATTERN IS EXPECTED TO SLOW DOWN DUE TO BLOCKING OVER THE NORTH ATLANTIC AND EUROPE. HOWEVER, SINCE THE EUROPEAN SOLUTION IS ACTUALLY SLOWER THAN THE GFS WITH THE TROUGH AND SLOWS PATTERN PROGRESSION OVERALL, IT SEEMS PLAUSIBLE LOCALLY. EARLY NEXT WEEK THE OVERALL CONSENSUS IS FOR HIGH PRESSURE RIDGING TO INCREASE OVER THE PACIFIC NORTHWEST WITH THE NEXT UPPER LEVEL TROUGH IN THE GULF OF ALASKA CLOSING OFF WEST OF THE COAST BY WEDNESDAY. THE CANADIAN MODEL IS THE EXCEPTION, IN QUICKLY BRINGING THE NEXT TROUGH INTO THE AREA ON TUESDAY, AS THE OTHER MODELS HAD SHOWN IN RECENT PREVIOUS RUNS THE LAST FEW DAYS. EXPECT THAT THE GFS/EC CAMP IS MOST LIKELY TO BE CORRECT, LEADING TO THE KEY QUESTION OF HOW FAR EAST THE LOW WILL MAKE IT BEFORE IT CLOSES OFF. MOST OF THE TIME FEATURES SUCH AS THESE END UP FURTHER WEST THAN EVEN THE MODELS INDICATE. THUS, HAVE GONE ALONG WITH THE HIGHER PROBABILITY SOLUTION THAT THIS LOW WILL CLOSE OFF TO OUR WEST EARLY NEXT WEEK AND PROVIDE A PERIOD OF TEMPERATURES AT TO A FEW DEGREES ABOVE DAILY NORMALS. BTL && .MFR WATCHES/WARNINGS/ADVISORIES... OR...WINTER WEATHER ADVISORY UNTIL 7 AM PDT WEDNESDAY FOR ORZ031. CA...NONE. PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT WEDNESDAY FOR PZZ356. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT THURSDAY FOR PZZ356. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT WEDNESDAY FOR PZZ350. SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT WEDNESDAY FOR PZZ370. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT WEDNESDAY FOR PZZ370. SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT THURSDAY FOR PZZ376. HAZARDOUS SEAS WARNING UNTIL 11 PM PDT WEDNESDAY FOR PZZ376. $$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
531 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT OVER WESTERN PENNSYLVANIA WILL CONTINUE TO PUSH TO THE EAST AND SHOULD BE OUT OF THE AREA BY LATE AFTERNOON. TROPICAL MOISTURE AND HIGH WIND SHEAR WILL CREATE THE POSSIBILITY OF STRONG THUNDERSTORMS AND BRIEF HEAVY RAIN AS THE COLD FRONT MOVES THROUGH. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY. A WEAK LOW PRESSURE AREA MAY DEVELOP TO OUR SOUTH DURING THE MIDDLE OF THE WEEK AND CRAWL SLOWLY NORTHWARD THROUGH THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CLOUDS NOW COVER MOST OF THE AREA...BUT RAINFALL JUST STARTING TO ENTER THE WESTERN HIGHLANDS. THE COLD FRONT SEEMS TO BE JUST AT THE LEADING EDGE OF THE RAIN. A STEADY PROGRESSION OF BOTH THE FRONT AND THE RAIN SHIELD WILL OCCUR THROUGH THE DAY. ALL MODELS IN VERY GOOD AGREEMENT RIGHT NOW. CONFIDENCE IS HIGH IN THE FORECAST TIMING. SREF RAINFALL AMOUNTS OF BETWEEN ONE AND ONE AND A HALF INCHES SEEMS REASONABLE. THEE DURATION OF THE RAIN SHOULD BE ABOUT 6 HRS...WHICH SHOULD KEEP ANY FLOODING WORRIES TO A BARE MINIMUM. SOME PONDING OF WATER IN THE NORMAL PLACES...BUT NOT EVEN SMALL STREAM FLOODING. MUCH OF THE AREA HAS BEEN QUITE DRY LATELY. THE MAIN FORECAST PROBLEM TODAY IS HOW UNSTABLE IT WILL GET OVER THE EASTERN HALF OF THE AREA THIS AFTERNOON. CLOUDS COVER THE AREA AT 5 AM AND DEEP SERLY FLOW AHEAD OF THE FRONT SHOULD ONLY REINFORCE THE CLOUD COVER. TEMPS MAY BE AT THEIR MAXES IN THE WESTERN HIGHLANDS...BUT THE EAST COULD HAVE 6-7 HRS OF POTENTIAL HEATING. THE COLD FRONT SHOULD BE PASSING THROUGH STATE COLLEGE ABOUT NOON/1 PM...AND HARRISBURG AROUND 2/3 PM. AREAS TO THE EAST OF THE FRONT WHICH CAN GENERATE SOME MODERATE INSTABILITY COULD HAVE SOME THUNDERSTORMS DEVELOP IN THE VERY STRONG SWRLY FLOW AHEAD OF THE FRONT. THE WINDS JUST 1-2KFT OFF THE GROUND WILL BE RACING AT 50KTS. IT WON/T TAKE MUCH TO MIX THAT DOWN...BUT THE CLOUDS WILL CUT DOWN ON HEATING WHICH WILL COUNTER-BALANCE THE THREAT. SPC DOES PLACE THE ERN HALF OF THE AREA INTO SLIGHT RISK. BUT THE LACK OF HEATING WILL BE THE TRICK. NAM MAKES LI AROUND -4 WITH TT AT 46 AND CAPE IN THE 1000+ RANGE AT MDT LATE THIS MORNING. SO A MENTION OF GUSTY WINDS IS AN EASY CALL...BUT MENTIONING SEVERE IS A BIT OF A STRETCH. CLEAR SLOT WILL LIKELY DEVELOP AFTER THE RAIN SHIELD MOVES TO THE EAST IN ALL LOCATIONS...BUT THE WNW FLOW BEHIND IT WILL LIKELY BRING CLOUDS BACK INTO THE NW/LAURELS THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... DRYING TAKES PLACE VERY QUICKLY AFTER FROPA. ALL PRECIP SHOULD BE TO THE EAST AT THE START OF THE PERIOD. SOME POST-FRONTAL COLD ADVECTION CLOUDS ARE POSSIBLE IN THE MOUNTAINS TONIGHT...BUT CLEAR SKIES EXPECTED ELSEWHERE. TEMPS WILL TAKE A TUMBLE INTO THE 40S TONIGHT...AND RIVER VALLEY FOG IS POSSIBLE. BUT THE WINDS WILL STAY UP FOR AT LEAST THE FIRST PART OF THE NIGHT. ANY CLOUDS WILL DISSIPATE ON TUESDAY...BUT SCT DIURNAL CU MAY DEVELOP UNDER THE COLD POCKET ALOFT AIR WITH HIGH AMBIENT MOISTURE FROM THE RAIN TODAY. 8H TEMPS DROP INTO THE LOWER SINGLE DIGITS BY TUES MORNING AND HOLD THERE FOR THE DAYTIME. MAXES WILL THEREFORE BE HELD TO THE 50S IN THE MOUNTAINS AND LOWER TO MID 60S ELSEWHERE THANKS TO THE DOWNSLOPE IN THE SERN HALF. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HAVE TWEAKED WED NIGHT-THURS NIGHT TO REFLECT THE POSSIBLE EFFECTS OF A LOW SLATED TO DEVELOP TO THE SOUTH ALONG THE EASTERN SEABOARD. THIS COULD BRING SHOWERS UP INTO THE SRN/SERN PARTS OF THE AREA...AND HOLD TEMPS DOWN A BIT AS WELL. PREV DISCO... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS CONTINUE ACROSS WESTERN AIRFIELDS EARLY THIS MORNING AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER THIS MORNING. CIGS AT SUSQUEHANNA RIVER VALLEY TAF SITES...MDT...LNS AND IPT HAVE FALLEN INTO MVFR RANGE AS GUSTY S/SE WINDS...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES HAVE PUSHED MARINE LAYER FROM THE ATLANTIC OCEAN TO PUSH NORTHWESTWARD ACROSS CWA. EXPECT EXPANSION OF THE MVFR/IFR STRATOCU DECK AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. FOCUS THEN TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...DANGELO/CERU AVIATION...GARTNER/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
313 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT OVER WESTERN PENNSYLVANIA WILL CONTINUE TO PUSH TO THE EAST AND SHOULD BE OUT OF THE AREA BY LATE AFTERNOON. TROPICAL MOISTURE AND HIGH WIND SHEAR WILL CREATE THE POSSIBILITY OF STRONG THUNDERSTORMS AND BRIEF HEAVY RAIN AS THE COLD FRONT MOVES THROUGH. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY AND KEEP MAINLY FAIR WEATHER OVER THE FORECAST AREA THROUGH THE REST OF THE WEEK. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... COLD FRONT IS VISIBLE ON RADAR MOSAIC NEAR KPIT AND JUST PAST KERI. WIND SHIFT/PRESSURE RISES ARE SEEN IN MANY OBS OVER ERN OHIO. RAIN SHIELD IS BEHIND THE FRONT...BUT STRONG SRLY LLVL JET WILL LIKELY KEEP THE SHOWERS MOVING RIGHT ALONG WITH THE FRONT THROUGH THE REST OF THE NIGHT AND EARLY THIS MORNING. LITTLE SFC- BASED INSTABILITY IS POSSIBLE BEFORE SUNRISE. GUSTY WIND SHOULD CONTINUE AS THE PRESSURE GRADIENT IS TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM TUESDAY/... THE MAIN ACTION OF THE WEEK AHEAD WILL BE CAPTURED IN THIS PERIOD AS A RELATIVELY STRONG SFC COLD FRONT PUSHES EAST ACROSS THE COMMONWEALTH. A HIGHLY ANOMALOUS SOUTHERLY LLJ /50KTS AND PLUS 3-4 SIGMA VIA THE 09Z AND 12Z SREF AND GEFS/ WILL SLIDE EAST ALONG AND AHEAD OF THE FRONT MONDAY MORNING INTO EARLY MONDAY AFTERNOON. EVEN THE SEEMINGLY HARMLESS /AND LOW/ FEW TO SEVERAL HUNDRED JOULES OF SFC-BASED CAPE GENERATED IN THE MAINLY CLOUDY AIRMASS AHEAD OF THE FRONT WILL BE ENOUGH TO COMBINE WITH THE STRONG DEEP-LAYER SHEAR TO POSE THE THREAT FOR A NCFRB AND A FEW SWATHS OF STRONG/DAMAGING STRAIGHT LINE WINDS. THE SHARPLY VEERING AND VERY STRONG LLVL WIND PROFILE WILL ALSO YIELD HIGH 0-3KM HELICITY OF 250-350 M2/S2...WHICH WILL BE CAPABLE OF SUPPORTING SOME LOW-TOPPED AND FAST NEWD MOVING MINI SUPERCELLS WELL AHEAD OF THE COLD FRONT /AND A FEW BKN-S SIGNATURES WITHIN THE NCFRB/. HIGH TEMPS WILL BE REACHED EARLY IN THE DAY ACROSS THE WEST...AND EARLY AFTERNOON ACROSS THE SUSQ VALLEY WITH FEW TO SVRL DEG DIP IN TEMPS BEHIND THE FRONT. BEST WIND GUST POTENTIAL WILL BE ALONG AND AHEAD OF THE COLD FRONT WITH A GUSTY /BUT NOT IMPRESSIVE/ WESTERLY FLOW BEHIND THE FRONT. STORM TOTAL RAINFALL WILL LIKELY RANGE FROM 1 TO 1.5 INCHES IN MOST LOCATIONS...WHICH IS A DEFINITE DOWNWARD ADJUSTMENT FROM THE PAST FEW DAYS GIVEN THE FACT THAT THERE WILL BE VERY LITTLE INFLUENCE FROM THE REMNANTS OF TS KAREN THAT WILL WEAKEN FURTHER OVER THE NEXT 36 HOURS OVER THE SERN STATES. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS CONTINUE ACROSS WESTERN AIRFIELDS EARLY THIS MORNING AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER THIS MORNING. CIGS AT SUSQUEHANNA RIVER VALLEY TAF SITES...MDT...LNS AND IPT HAVE FALLEN INTO MVFR RANGE AS GUSTY S/SE WINDS...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES HAVE PUSHED MARINE LAYER FROM THE ATLANTIC OCEAN TO PUSH NORTHWESTWARD ACROSS CWA. EXPECT EXPANSION OF THE MVFR/IFR STRATOCU DECK AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. FOCUS THEN TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...LAMBERT LONG TERM...DANGELO/CERU AVIATION...GARTNER/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
120 AM EDT MON OCT 7 2013 .SYNOPSIS... A COLD FRONT OVER WESTERN PENNSYLVANIA WILL CONTINUE TO PUSH TO THE EAST AND SHOULD BE OUT OF THE AREA BY LATE AFTERNOON. TROPICAL MOISTURE AND HIGH WIND SHEAR WILL CREATE THE POSSIBILITY OF STRONG THUNDERSTORMS AND BRIEF HEAVY RAIN AS THE COLD FRONT MOVES THROUGH. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY AND KEEP MAINLY FAIR WEATHER OVER THE FORECAST AREA THROUGH THE REST OF THE WEEK. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... COLD FRONT IS VISIBLE ON RADAR MOSAIC NEAR KPIT AND JUST PAST KERI. WIND SHIFT/PRESSURE RISES ARE SEEN IN MANY OBS OVER ERN OHIO. RAIN SHIELD IS BEHIND THE FRONT...BUT STRONG SRLY LLVL JET WILL LIKELY KEEP THE SHOWERS MOVING RIGHT ALONG WITH THE FRONT THROUGH THE REST OF THE NIGHT AND EARLY THIS MORNING. LITTLE SFC- BASED INSTABILITY IS POSSIBLE BEFORE SUNRISE. GUSTY WIND SHOULD CONTINUE AS THE PRESSURE GRADIENT IS TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM TUESDAY/... THE MAIN ACTION OF THE WEEK AHEAD WILL BE CAPTURED IN THIS PERIOD AS A RELATIVELY STRONG SFC COLD FRONT PUSHES EAST ACROSS THE COMMONWEALTH. A HIGHLY ANOMALOUS SOUTHERLY LLJ /50KTS AND PLUS 3-4 SIGMA VIA THE 09Z AND 12Z SREF AND GEFS/ WILL SLIDE EAST ALONG AND AHEAD OF THE FRONT MONDAY MORNING INTO EARLY MONDAY AFTERNOON. EVEN THE SEEMINGLY HARMLESS /AND LOW/ FEW TO SEVERAL HUNDRED JOULES OF SFC-BASED CAPE GENERATED IN THE MAINLY CLOUDY AIRMASS AHEAD OF THE FRONT WILL BE ENOUGH TO COMBINE WITH THE STRONG DEEP-LAYER SHEAR TO POSE THE THREAT FOR A NCFRB AND A FEW SWATHS OF STRONG/DAMAGING STRAIGHT LINE WINDS. THE SHARPLY VEERING AND VERY STRONG LLVL WIND PROFILE WILL ALSO YIELD HIGH 0-3KM HELICITY OF 250-350 M2/S2...WHICH WILL BE CAPABLE OF SUPPORTING SOME LOW-TOPPED AND FAST NEWD MOVING MINI SUPERCELLS WELL AHEAD OF THE COLD FRONT /AND A FEW BKN-S SIGNATURES WITHIN THE NCFRB/. HIGH TEMPS WILL BE REACHED EARLY IN THE DAY ACROSS THE WEST...AND EARLY AFTERNOON ACROSS THE SUSQ VALLEY WITH FEW TO SVRL DEG DIP IN TEMPS BEHIND THE FRONT. BEST WIND GUST POTENTIAL WILL BE ALONG AND AHEAD OF THE COLD FRONT WITH A GUSTY /BUT NOT IMPRESSIVE/ WESTERLY FLOW BEHIND THE FRONT. STORM TOTAL RAINFALL WILL LIKELY RANGE FROM 1 TO 1.5 INCHES IN MOST LOCATIONS...WHICH IS A DEFINITE DOWNWARD ADJUSTMENT FROM THE PAST FEW DAYS GIVEN THE FACT THAT THERE WILL BE VERY LITTLE INFLUENCE FROM THE REMNANTS OF TS KAREN THAT WILL WEAKEN FURTHER OVER THE NEXT 36 HOURS OVER THE SERN STATES. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS MAJORITY OF CENTRAL PA AT MIDNIGHT AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER TONIGHT/EARLY MON. BIGGEST AVIATION CONCERN FOR NEXT SEVERAL HOURS WILL BE A GUSTY S/SE WIND...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES. MOIST FLOW IS ALLOWING A MARINE LAYER FROM THE ATLANTIC TO PUSH NORTHWESTWARD ACROSS CWA...RAISING DEWPOINTS BY NEARLY 10F. BIGGER IMPACTS OF THIS MARINE LAYER ARE BEGINNING TO DEVELOP AS POTENT SOUTHERLY LOW-LEVEL JET SLIDES EAST FROM OHIO VALLEY...PROVIDING THE LIFT TO INITIATE DEVELOPMENT OF AN MVFR/IFR STRATOCU DECK. THESE CLOUDS WILL DEVELOP FIRST IN THE MOIST AIRMASS OVER EASTERN SECTIONS...AND KIPT HAS ALREADY DROPPED TO MVFR...AND SPREAD INTO OTHER AREAS AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. THEN FOCUS TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...LAMBERT LONG TERM...DANGELO/CERU AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1206 AM EDT MON OCT 7 2013 .SYNOPSIS... THE REGION REMAINS IN THE WARM SECTOR OF A LOW MOVING THROUGH THE UPPER GR LAKES. THE ASSOCIATED COLD FRONT WILL MOVE THROUGH ON MONDAY AS TROPICAL MOISTURE FLOWS UP INTO THE STATE. HIGH PRESSURE IS EXPECTED TO RETURN FOR TUESDAY AND KEEP MAINLY FAIR WEATHER OVER THE FORECAST AREA THROUGH THE REST OF THE NEW WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE COLD FRONT IS MOVING INTO EASTERN OHIO ACCOMPANIED BY AN AREA OF HEAVY RAIN SHOWERS AND ISOLATED THUNDERSTORMS. LOCALLY...THE CWA IS DRY AND QUITE MILD. HAVEN`T REALLY CHANGED MUCH OF THE FORECAST DURING THE OVERNIGHT...STILL LOOKS GOOD FOR RAIN TO BE MOVING INTO WESTERN AREAS AROUND OR SHORTLY AFTER 06Z...AND SPREADING QUICKLY EAST AFTER THAT. THE STRONG...SOUTHERLY LLJ WILL SHIFT EAST FROM THE OHIO VALLEY AND INTO THE REGION OVERNIGHT. THIS WILL QUICKLY INCREASE SFC WINDS...WITH THE HIGHER TERRAIN AND LOCATIONS NORTH OF GAPS IN THE RIDGES SEEING WIND GUSTS OVER 30 MPH. INCREASED LARGE SCALE LIFT ASSOCIATED WITH THIS LLJ AND A SERIES OF UPPER SHORT WAVES LIFTING QUICKLY NNE AHEAD OF THE MAIN OHIO VALLEY TROUGH AND SFC COLD FRONT WILL LEAD TO THE DEVELOPMENT OF NUMEROUS SHOWERS AND EMBEDDED LOW TOPPED TSRA OVER THE WESTERN PA AFTER MIDNIGHT. THIS CONVECTION MAY REACH THE I-99/RT 220 CORRIDOR BETWEEN 10-12Z MONDAY. LOOK FOR ONE MORE NIGHT OF UNSEASONABLY MILD TEMPS WITH LOW IN THE 60-65F RANGE...THANKS TO SIMILARLY HIGH DEWPOINTS...AND THE INCREASING CLOUDS/WIND. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... THE MAIN ACTION OF THE WEEK AHEAD WILL BE CAPTURED IN THIS PERIOD AS A RELATIVELY STRONG SFC COLD FRONT PUSHES EAST ACROSS THE COMMONWEALTH. A HIGHLY ANOMALOUS SOUTHERLY LLJ /50KTS AND PLUS 3-4 SIGMA VIA THE 09Z AND 12Z SREF AND GEFS/ WILL SLIDE EAST ALONG AND AHEAD OF THE FRONT MONDAY MORNING INTO EARLY MONDAY AFTERNOON. EVEN THE SEEMINGLY HARMLESS /AND LOW/ FEW TO SEVERAL HUNDRED JOULES OF SFC-BASED CAPE GENERATED IN THE MAINLY CLOUDY AIRMASS AHEAD OF THE FRONT WILL BE ENOUGH TO COMBINE WITH THE STRONG DEEP-LAYER SHEAR TO POSE THE THREAT FOR A NCFRB AND A FEW SWATHS OF STRONG/DAMAGING STRAIGHT LINE WINDS. THE SHARPLY VEERING AND VERY STRONG LLVL WIND PROFILE WILL ALSO YIELD HIGH 0-3KM HELICITY OF 250-350 M2/S2...WHICH WILL BE CAPABLE OF SUPPORTING SOME LOW-TOPPED AND FAST NEWD MOVING MINI SUPERCELLS WELL AHEAD OF THE COLD FRONT /AND A FEW BKN-S SIGNATURES WITHIN THE NCFRB/. HIGH TEMPS WILL BE REACHED EARLY IN THE DAY ACROSS THE WEST...AND EARLY AFTERNOON ACROSS THE SUSQ VALLEY WITH FEW TO SVRL DEG DIP IN TEMPS BEHIND THE FRONT. BEST WIND GUST POTENTIAL WILL BE ALONG AND AHEAD OF THE COLD FRONT WITH A GUSTY /BUT NOT IMPRESSIVE/ WESTERLY FLOW BEHIND THE FRONT. STORM TOTAL RAINFALL WILL LIKELY RANGE FROM 1 TO 1.5 INCHES IN MOST LOCATIONS...WHICH IS A DEFINITE DOWNWARD ADJUSTMENT FROM THE PAST FEW DAYS GIVEN THE FACT THAT THERE WILL BE VERY LITTLE INFLUENCE FROM THE REMNANTS OF TS KAREN THAT WILL WEAKEN FURTHER OVER THE NEXT 36 HOURS OVER THE SERN STATES. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE MODELS CONTINUE TO BE IN AGREEMENT WITH A NEARLY NEUTRAL TROUGH EXTENDING FROM THE LOW CENTER THAT CONTINUES TO MOVE NORTHWARD. COOLER AIR WILL ADVECT INTO THE REGION BEHIND THE FRONT MONDAY NIGHT...AS ANY LINGERING SHOWERS SHOULD BE GONE BY 06Z TUESDAY. THE PATTERN FLATTENS OUT QUICKLY TUESDAY MORNING AS SURFACE HIGH PRESSURE SETTLES IN FOR THE LONG HAUL ON TUESDAY. THE UPPER RIDGE RE-ASSERTS IT/S STRENGTH OVER THE ERN U.S. TEMPERATURES WILL BE COOLER THAN NORMAL ON TUESDAY...WITH MORE SEASONABLE TEMPS THROUGH THE REST OF THE WEEK. WITH THE DRY AIR AND SUBSIDENCE EVERY MORNING...IT WILL BE A CLASSIC SET-UP FOR VERY CHILLY MORNINGS. HOWEVER...THE ABNORMALLY HIGH 5H HEIGHTS...8H TEMPS OF 10 TO 12C AND THICKNESSES IN THE MID 560S WILL PRECLUDE ALL BE THE VERY COLDEST LOCATIONS FROM GETTING NEAR FREEZING AT NIGHT. THE COLDEST TIME FRAME WILL BE TUESDAY NIGHT/WED MORNING. FROST IS POSSIBLE ACROSS THE NORTH. RESIDUAL MOISTURE MOVING ONSHORE...ALONG WITH A WEAK SFC LOW COULD ALLOW FOR EASTERLY FLOW LATE THURSDAY INTO FRIDAY. THIS MOIST ONSHORE FLOW COULD BRING ISOLATED SHOWERS THURSDAY NIGHT THROUGH FRIDAY AFTERNOON TO THE LOWER SUSQUEHANNA VALLEY. THIS LOW PRESSURE SFC/ALOFT WILL CONTINUE TO DEVELOP OVER THE WESTERN ATLANTIC UNDER THE UPPER RIDGE AND WILL CONTINUE TO RETROGRADE INTO SATURDAY...BEFORE DRIFTING OUT TO SEA. HAVE SLIGHTLY INCREASED POPS IN THE SOUTHEAST DURING THIS TIMEFRAME. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... VFR CONDITIONS ACROSS MAJORITY OF CENTRAL PA AT MIDNIGHT AS REGION REMAINS IN WARM SECTOR...AWAITING ARRIVAL OF A COLD FRONT LATER TONIGHT/EARLY MON. BIGGEST AVIATION CONCERN FOR NEXT SEVERAL HOURS WILL BE A GUSTY S/SE WIND...WITH GUSTS PEAKING AT AROUND 25 MPH AT TIMES. MOIST FLOW IS ALLOWING A MARINE LAYER FROM THE ATLANTIC TO PUSH NORTHWESTWARD ACROSS CWA...RAISING DEWPOINTS BY NEARLY 10F. BIGGER IMPACTS OF THIS MARINE LAYER ARE BEGINNING TO DEVELOP AS POTENT SOUTHERLY LOW-LEVEL JET SLIDES EAST FROM OHIO VALLEY...PROVIDING THE LIFT TO INITIATE DEVELOPMENT OF AN MVFR/IFR STRATOCU DECK. THESE CLOUDS WILL DEVELOP FIRST IN THE MOIST AIRMASS OVER EASTERN SECTIONS...AND KIPT HAS ALREADY DROPPED TO MVFR...AND SPREAD INTO OTHER AREAS AS NIGHT PROGRESSES. SCT SHOWERS WILL BECOME POSSIBLE IN THE VERY MOIST AIR OVER E PA AND THE SUSQ VALLEY AFTER 08Z AS LARGE SCALE LIFT BEGINS TO INCREASE...AND THESE SHOWERS ARE HINTED AT IN THE HRRR MODEL FORECAST. SO ADDED VCSH TO EASTERN TERMINALS OVERNIGHT. THEN FOCUS TURNS TO POTENT SFC COLD FRONT EXPECTED TO BE NEAR A KBFD TO KJST LINE BY 12Z...AND PUSHING STEADILY EAST ACROSS THE REST OF THE REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. A NARROW LINE /ABOUT 4 HOURS/ OF HEAVY SHOWERS/LOW-TOPPED TSRA SHOULD ACCOMPANY THE IMMEDIATE CFROPA...WHILE ISOLATED SUPERCELLS ARE POSSIBLE WELL TO THE EAST OF THE FRONT IN THE HIGHLY SHEARED ENVIRONMENT /MAINLY AFTER SUNRISE IN EASTERN SECTIONS/. THESE INDIVIDUAL CELLS WILL TRACK RAPIDLY TO THE NE AT 40 KTS PLUS. ANY OF THESE LEAD STORMS /OR THE EXPECTED LINE ALONG THE FRONT/ COULD MIX DOWN STRONG WIND GUSTS TO THE SFC. CONDITIONS IMPROVE FROM WEST TO EAST WITHIN A FEW HOURS OF FROPA AS PRECIP COMES TO AN END AND CEILINGS/VSBYS RETURN TO VFR FOR THE SECOND HALF OF MON /AS RIDGING BEGINS IN LOWER LEVELS/. WINDS TURN WESTERLY AND REMAIN AROUND 15 MPH GUSTING TO 25 MPH BEFORE DIMINISHING LATER IN THE DAY. CIG RESTRICTIONS LIKELY IN WESTERN/NORTHERN MTNS MON NIGHT AS COLDEST MID LEVEL AIR RETREATS TO THE NE AND LOW LEVEL SUBSIDENCE INVERSION SQUEEZES MOISTURE INTO A STABLE STRATOCU DECK. OUTLOOK... TUE...SCT AM SHOWERS/LOW CIGS POSSIBLE N AND W. WED-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT LONG TERM...DANGELO/CERU AVIATION...RXR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
156 PM EDT MON OCT 7 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE NORTHEASTERN STATES WILL GIVE OUR AREA A COOL NORTHEAST FLOW OF AIR THROUGH MUCH OF THE WEEK. EXPECT LOW PRESSURE TO MOVE FROM THE GEORGIA COAST TO EASTERN NORTH CAROLINA DURING MID WEEK AND STAY IN THAT VICINITY INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... AS OF 10AM EDT MONDAY...BROKEN LINE OF CONVECTION CONTINUES TO PUSH EAST OF THE I77 CORRIDOR INTO CENTRAL NC. A FEW LIGHT SHOWERS WILL BE A POSSIBILITY OVER THE NEXT FEW HOURS BEHIND THE LEADING LINE. THEREFORE KEPT CHANCE POPS THROUGH MIDDAY OUTSIDE OF THE MOUNTAINS. OTHERWISE...DECIDED TO GO AHEAD AND LOWER POPS ACROSS THE HIGHER TERRAIN AS THE FRONT PUSHES THROUGH ADVECTING IN MUCH MORE STABLE AIR. SKY CONDITIONS WILL SLOWLY IMPROVE ACROSS THE MOUNTAINS THROUGH THE DAY AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT. ELSEWHERE...CLOUDS WILL PERSIST THROUGH THE AFTERNOON HOURS AND INTO MONDAY EVENING AS DEEP LAYER MOISTURE PREVAILS AHEAD OF THE FRONT. OTHER THAN THE ABOVE MENTIONED POP/WX/SKY ADJUSTMENTS...NO OTHER CHANGES WERE MADE TO THE FCST AT THIS TIME. PREVIOUS DISCUSSION... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 130 PM MON...LOW PRES OVER THE SE COASTAL WATERS TUE NIGHT WILL PUSH ATLANTIC AND TROPICAL MOISTURE BACK INLAND ACROSS THE COASTAL PLAIN OF THE CAROLINAS THROUGH WED. THE MAJORITY OF THE 12Z MODEL RUNS KEEP THE HEAVY PRECIPITATION WITH THIS SYSTEM CONFINED TO MAINLY COASTAL SECTIONS. HOWEVER...THE CANADIAN CMC AND A FAIR CHUNK OF THE ENSEMBLE MEMBERS THROW A BIT MORE PRECIPITATION WESTWARD INTO THE PIEDMONT TUE NIGHT/WED. WILL LEAN TOWARD THE MORE AGGRESSIVE SOLUTION GIVEN THE HEALTHY PRESENTATION ON WATER VAPOR TODAY OF THE WAVE THAT BECOMES THE COASTAL SYSTEM. DESPITE LEANING TOWARD THE WETTER SIDE OF GUIDANCE...THE BL TO 850 MB FLOW WILL REMAIN NRLY ENOUGH AROUND THE COASTAL SYSTEM TO KEEP QPF AMOUNTS DOWN AND NOT ALLOW MUCH OF ANY UPSLOPE ENHANCEMENT INTO THE BLUE RIDGE THROUGH WED NIGHT. THE MAIN FEATURE TO WATCH WOULD BE IF ANY BANDED SHOWERS COULD WRAP BACK INTO THE CLT AREA. OTHERWISE...WILL CONTINUE TO FEATURE A SMALLER THAN GUIDANCE DIURNAL RANGE ON TEMPS. AS THE SYSTEM MOVES UP THE COAST TO THE OUTER BANKS ON THU...MOISTURE MAY CONTINUE TO WRAP BACK WWD INTO THE NC PIEDMONT. ANY ADDITIONAL QPF AMOUNTS WOULD BE LIGHT. WILL CONTINUE TO FEATURE TEMPS BELOW GUIDANCE ON THU AFTN...BUT LESS SO THAN ON WED. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... AS OF 140 PM MON FOR THE MEDIUM RANGE...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST HANGS AROUND OVER EASTERN NC AND VA INTO SATURDAY THEN EITHER MOVES EAST OR NORTH DEPENDING ON MODEL CHOICE. THIS LOW IS CLOSE ENOUGH TO PRODUCE SOME LIGHT PRECIP JUST EAST OF OUR ZONES THURSDAY EVENING AND THEN HIGH PRESSURE TO OUR WEST AND NORTH BECOMES MORE OF AN INFLUENCE. THE GFS AND ECMWF KEEP THE LOW OVER EASTERN NC THROUGH SATURDAY. THE ECMWF THEN MOVES THE LOW NORTH UP THE COAST TO MASS EARLY IN THE WEEK. THE GFS MOVES THE LOW EAST AND THEN NORTH TOWARD NOVA SCOTIA. THE GFS KEEPS AN ALMOST PERSISTENT LOW LEVEL NE WIND FLOW OVER OUR AREA THROUGH MOST OF THE PERIOD. THE ECMWF HAS A MORE LIGHT AND VARIABLE WIND FLOW. SOME SHORTWAVE ENERGY WILL BE CROSSING THE LOWER MISSISSIPPI VALLEY BY MONDAY NIGHT AND INCREASE CLOUDS OVER NE GA AND THE MTNS. STILL KEEPING IT DRY THROUGH THE PERIOD. TEMPERATURES WILL BE NEAR NORMAL FOR THIS MEDIUM RANGE PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH THE ONLY POSSIBLE EXCEPTION BEING FOR SCATTERED AFTERNOON TSRA. ADDED AN MVFR TEMPO GROUP FROM 19Z-23Z TO ACCOUNT FOR LOW END INSTABILITY ACROSS THE NC PIEDMONT THIS AFTERNOON. MODEL SOUNDINGS INDICATE MARGINAL INSTABILITY THUS COULD NOT RULE OUT CONVECTION. OTHERWISE...SKIES SHOULD REMAIN BKN/OVC THROUGH THE REMAINDER OF THE TAF CYCLE AS MOISTURE AXIS ASSOCIATED WITH FRONTAL BOUNDARY STALLS ALONG AND SOUTH OF THE I85 CORRIDOR. INITIALIZED WINDS OUT OF THE WEST THEN VEERING NORTHWEST BY AROUND 19Z AS THE FRONT PUSHES THROUGH. WINDS WILL REMAIN ELEVATED THROUGH THE EVENING AS HIGH PRESSURE BUILDS IN FROM THE NORTH. AS THIS RIDGE BUILDS OVERNIGHT...INCREASING PRESSURE GRADIENT FORCES WILL YIELD THE POSSIBILITY FOR GUSTY WINDS IN THE MORNING. THUS ADDED MENTION OF NORTHEAST GUSTS NEARING 20KTS THROUGH MIDDAY. ELSEWHERE...VFR CONDITIONS SHOULD PREVAIL THROUGH THE ENTIRE TAF CYCLE. WITH THAT SAID...DID INITIALIZE KAND WITH A BKN MVFR CIG WHICH SHOULD NOT LAST BUT FOR MORE THAN AN HOUR OR SO. OTHERWISE...SKIES SHOULD SLOWLY CLEAR IN THE LOW/MID LEVELS FROM WEST TO EAST AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT AT KAVL. AS FOR OTHER LOCATIONS...KEPT MENTION OF LOW END VFR CIGS THROUGH THE REMAINDER OF THE TAF CYCLE DUE TO PROXIMITY OF STALLED MOISTURE AXIS. AS WITH KCLT ABOVE...WINDS WILL SHIFT NORTHWESTERLY THROUGH THE FIRST FEW HORUS OF THIS TAF PERIOD AND WILL REMAIN ELEVATED OVERNIGHT. THESE ELEVATED WINDS COMBINED WITH SFC DEWPOINTS IN THE 40S TO LOWER 50S WILL KEEP FOG CHANCES SLIM. WINDS WILL INCREASE FURTHER AND VEER EASTERLY DURING THE MORNING HOURS WITH SOME GUSTING AT KGSP AND KGMU. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW AND MOISTURE ASSOCIATED WITH THE REMNANTS OF TROPICAL STORM KAREN MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES LATER IN THE WEEK. CONFIDENCE TABLE... 18-24Z 00-06Z 06-12Z 12-18Z KCLT HIGH 93% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 98% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 97% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 87% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...CDG/WIMBERLEY SHORT TERM...HG LONG TERM...DEO AVIATION...CDG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1017 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 10AM EDT MONDAY...BROKEN LINE OF CONVECTION CONTINUES TO PUSH EAST OF THE I77 CORRIDOR INTO CENTRAL NC. A FEW LIGHT SHOWERS WILL BE A POSSIBILITY OVER THE NEXT FEW HOURS BEHIND THE LEADING LINE. THEREFORE KEPT CHANCE POPS THROUGH MIDDAY OUTSIDE OF THE MOUNTAINS. OTHERWISE...DECIDED TO GO AHEAD AND LOWER POPS ACROSS THE HIGHER TERRAIN AS THE FRONT PUSHES THROUGH ADVECTING IN MUCH MORE STABLE AIR. SKY CONDITIONS WILL SLOWLY IMPROVE ACROSS THE MOUNTAINS THROUGH THE DAY AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT. ELSEWHERE...CLOUDS WILL PERSIST THROUGH THE AFTERNOON HOURS AND INTO MONDAY EVENING AS DEEP LAYER MOISTURE PREVAILS AHEAD OF THE FRONT. OTHER THAN THE ABOVE MENTIONED POP/WX/SKY ADJUSTMENTS...NO OTHER CHANGES WERE MADE TO THE FCST AT THIS TIME. PREVIOUS DISCUSSION... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA TODAY...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY. CHANCES WARRANT A TEMPO FOR THE FIRST COUPLE HOURS. LOW END GUSTS POSSIBLE WITH THE LINE ALSO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. TONIGHT...SOME MAINLY MIDLEVEL MOISTURE WILL RIDE BACK UP OVER THE FRONT AND BRING BACK A CIG TOWARD DAYBREAK. GUIDANCE GIVING A STRONG SIGNAL THIS WILL BE VFR. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NWLY WIND SHIFT ARRIVING EARLIER. IT MAY HAVE ALREADY OCCURRED BY 12Z IN THE MTNS...THEN LATER THIS MRNG FOOTHILLS AND UPPER PIEDMONT...MIDDAY ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. THE PIEDMONT WILL SEE CIGS FORM AGAIN LATE TONIGHT AS A FRONTAL WAVE SPREADS MOISTURE FROM THE STALLED FRONT BACK OVER THE REGION. WITH THE COOLER AIRMASS WORKING IN THIS EVENING...SFC SHOULD REMAIN DRY ENOUGH TO PRECLUDE FOG EXCEPT PERHAPS IN THE MOST SHELTERED MTN VALLEYS...KAVL BEING EXCLUDED. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES. CONFIDENCE TABLE... 14-20Z 20-02Z 02-08Z 08-14Z KCLT HIGH 94% HIGH 90% HIGH 100% HIGH 100% KGSP HIGH 82% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 82% HIGH 100% HIGH 100% HIGH 94% KHKY HIGH 80% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 91% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 91% HIGH 98% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...CDG/WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
806 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 8AM EDT MONDAY...LINE OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE EASTWARD ACROSS THE COVERAGE AREA WITH THE HEAVIEST CONVECTION BEING ALONG A LINE NEAR THE I77 CORRIDOR. THIS LINE WILL MOVE INTO CHARLOTTE METRO WITHIN THE HOUR. THE MAIN THREATS AT THIS TIME ARE GUSTY WINDS AND HEAVY RAINFALL. MEANWHILE TO THE WEST...LEADING EDGE OF THE COLD FRONT IS PUSHING THROUGH THE MOUNTAINS AND WILL CONTINUE MOVING EASTWARD THROUGH THE DAY. ADJUSTED EXTREME NEAR TERM POPS TO REFLECT LATEST RADAR TRENDS AND LEFT THE REMAINDER OF THE FORECAST AS IS. PREVIOUS DISCUSSION... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA TODAY...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY. CHANCES WARRANT A TEMPO FOR THE FIRST COUPLE HOURS. LOW END GUSTS POSSIBLE WITH THE LINE ALSO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. TONIGHT...SOME MAINLY MIDLEVEL MOISTURE WILL RIDE BACK UP OVER THE FRONT AND BRING BACK A CIG TOWARD DAYBREAK. GUIDANCE GIVING A STRONG SIGNAL THIS WILL BE VFR. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NWLY WIND SHIFT ARRIVING EARLIER. IT MAY HAVE ALREADY OCCURRED BY 12Z IN THE MTNS...THEN LATER THIS MRNG FOOTHILLS AND UPPER PIEDMONT...MIDDAY ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. THE PIEDMONT WILL SEE CIGS FORM AGAIN LATE TONIGHT AS A FRONTAL WAVE SPREADS MOISTURE FROM THE STALLED FRONT BACK OVER THE REGION. WITH THE COOLER AIRMASS WORKING IN THIS EVENING...SFC SHOULD REMAIN DRY ENOUGH TO PRECLUDE FOG EXCEPT PERHAPS IN THE MOST SHELTERED MTN VALLEYS...KAVL BEING EXCLUDED. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES. CONFIDENCE TABLE... 12-18Z 18-24Z 00-06Z 06-12Z KCLT HIGH 100% HIGH 80% HIGH 100% HIGH 100% KGSP MED 79% HIGH 94% HIGH 100% HIGH 100% KAVL MED 75% HIGH 100% HIGH 100% HIGH 100% KHKY MED 67% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 83% HIGH 96% HIGH 100% HIGH 100% KAND MED 79% HIGH 95% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...CDG/WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
734 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA TODAY...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY. CHANCES WARRANT A TEMPO FOR THE FIRST COUPLE HOURS. LOW END GUSTS POSSIBLE WITH THE LINE ALSO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. TONIGHT...SOME MAINLY MIDLEVEL MOISTURE WILL RIDE BACK UP OVER THE FRONT AND BRING BACK A CIG TOWARD DAYBREAK. GUIDANCE GIVING A STRONG SIGNAL THIS WILL BE VFR. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NWLY WIND SHIFT ARRIVING EARLIER. IT MAY HAVE ALREADY OCCURRED BY 12Z IN THE MTNS...THEN LATER THIS MRNG FOOTHILLS AND UPPER PIEDMONT...MIDDAY ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. THE PIEDMONT WILL SEE CIGS FORM AGAIN LATE TONIGHT AS A FRONTAL WAVE SPREADS MOISTURE FROM THE STALLED FRONT BACK OVER THE REGION. WITH THE COOLER AIRMASS WORKING IN THIS EVENING...SFC SHOULD REMAIN DRY ENOUGH TO PRECLUDE FOG EXCEPT PERHAPS IN THE MOST SHELTERED MTN VALLEYS...KAVL BEING EXCLUDED. OUTLOOK...MODERATELY SETTLED CONDITIONS WILL REMAIN THROUGH MIDWEEK THOUGH A WEAK UPPER LEVEL LOW MAY PRODUCE CIGS AND LIGHT PRECIP...WITH POSSIBLE RESTRICTIONS IN SHOWERS. MORNING MTN VALLEY FOG ALSO MAY IMPACT FLIGHT RULES. CONFIDENCE TABLE... 11-17Z 17-23Z 23-05Z 05-11Z KCLT HIGH 100% HIGH 85% HIGH 97% HIGH 100% KGSP MED 77% HIGH 92% HIGH 100% HIGH 100% KAVL MED 75% HIGH 98% HIGH 100% HIGH 100% KHKY MED 61% HIGH 98% HIGH 100% HIGH 100% KGMU HIGH 85% HIGH 92% HIGH 100% HIGH 100% KAND MED 79% HIGH 94% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
503 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 445 AM UPDATE...EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE NOW EVIDENTLY JUST EAST OF THE TENN/NC BORDER. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT A FEW TSTMS...THE QLCS WHICH MOVED THRU THE FOOTHILLS EARLIER THIS AM HAVING BECOME DISORGANIZED. STRONG LLVL SHEAR STILL PRESENT AND THOUGH RAP ANALYSIS STILL INDICATES SOME INSTABILITY LAPSE RATES MAY HAVE BECOME NEARLY NEUTRAL/MOIST ADIABATIC WITH THE COLUMN SATURATING. THE SHORTWAVE IS STILL MOVING INTO A MORE UNSTABLE ENVIRONMENT...ONE THAT HAS LARGELY BEEN UNTOUCHED TONIGHT. THUS DEVELOPMENT OF DISCRETE CONVECTION...MOSTLY SHOWERS WITH A LESSER NUMBER OF TSTMS...MAY STILL BE EXPECTED THIS MRNG EAST OF A GREENWOOD TO STATESVILLE LINE. TEMPS WILL LIKELY REMAIN NEARLY STEADY THRU DAYBREAK...EXCEPT IN THE HIGHER MTNS WHICH MAY SEE SOME COOLER AIR BEGIN TO FILTER IN. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... AT KCLT /09Z UPDATE/...COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS AFTN...PRECEDED BY SHRA/TSRA. A LINE OF HEAVY SHRA WITH A COUPLE EMBEDDED TSRA MAY BRING A PERIOD OF IFR CIGS/VSBY TO THE FIELD AROUND OR JUST AFTER DAYBREAK...BUT WITH MOST OF THE CONVECTION MOVING PARALLEL TO THE WHOLE LINE IT IS MOVING SLOWLY AND EITHER MAY NOT MAKE IT TO KCLT OR ARRIVE AFTER MORNING MIXING BEGINS. CHANCES WARRANT A TEMPO. MVFR CIG EXPECTED TO PERSIST UNTIL THE FROPA LIFTS THEM TO VFR AND STARTS A CLEARING TREND THIS AFTN. UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY PASSING OVERHEAD MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THEN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. ELSEWHERE...MUCH LIKE KCLT BUT WITH FROPA AND NLY WIND SHIFT ARRIVING EARLIER. IT IS EXPECTED JUST AFTER DAYBREAK IN THE MTNS...LATE MRNG FOOTHILLS AND UPPER PIEDMONT...EARLY AFTN ELSEWHERE. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM BEFORE THE FROPA. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. OUTLOOK...DRY AND COOL HIGH PRESSURE BUILDS IN MON NITE AND CONTINUES THRU THE WEEK. RESTRICTIONS SHUD BE LIMITED TO MORNING MTN VALLEY FOG. CONFIDENCE TABLE... 09-15Z 15-21Z 21-03Z 03-09Z KCLT MED 78% HIGH 81% HIGH 82% HIGH 100% KGSP HIGH 81% MED 68% HIGH 92% HIGH 100% KAVL MED 77% MED 79% HIGH 100% HIGH 100% KHKY HIGH 83% MED 74% HIGH 100% HIGH 100% KGMU HIGH 84% MED 78% HIGH 92% HIGH 100% KAND MED 76% MED 74% HIGH 93% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
337 AM EDT MON OCT 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA TODAY. ABUNDANT MOISTURE AND STRONG UPPER LEVEL WINDS WILL PROVIDE FOR HEAVY RAIN AND POSSIBLE SEVERE WEATHER ACROSS THE REGION. HIGH PRESSURE BUILDS BACK IN TUESDAY LASTING THROUGH THE REST OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... EARLY THIS MORNING...COLD FROPA IMMINENT WITH SFC TROUGH AND CONVERGENCE LINE EXTENDING DOWN THE SPINE OF THE APPALACHIANS. SHORTWAVE IMPULSE LEADING THE CORE OF THE UPPER TROUGH IN THE MODERATELY UNSTABLE ENVIRONMENT AHEAD OF THE FRONT CONTINUES TO SUPPORT TSTMS...MOST NOTABLY A LOW END QLCS MOVING INTO THE NC PIEDMONT AND NERN UPSTATE ZONES. THIS REFLECTS THE STRONG SHEAR...20 KT 0-1KM WITH 0-3KM HELICITY OF OVER 200 M2/S2. SPC MESOANALYSIS SHOWS THE LINE ENTERING HIGHER SFC BASED CAPE OVER THE ERN PIEDMONT...THOUGH AS NOTED BY PREVIOUS SHIFTS THE JUICIEST VALUES WILL REMAIN FURTHER SOUTH. LATEST 04Z HRRR INDICATES SOME NEW DEVELOPMENT ALONG THE SRN END OF THIS LINE AS INDIVIDUAL CONVECTIVE ELEMENTS MOVE NORTHEAST...AND THIS MATCHES RADAR TRENDS OVER THE PAST HOUR OR SO. THE UNIDIRECTIONAL SHEAR AND STRONG MIDLEVEL WINDS ARE ALLOWING FOR TRAINING TO OCCUR THERE ALSO...AND THIS APPEARS TO BE THE MAIN HYDRO CONCERN AT THIS TIME. THE LINE LOOKS TO GRADUALLY SHIFT EASTWARD OVER THE PIEDMONT THRU DAYBREAK. DISCRETE CONVECTIVE ACTIVITY EARLIER THIS EVENING NEAR THE CHARLOTTE METRO DID DIMINISH...BUT THE ENVIRONMENT SEEMS TO BE PRIMED FOR REDEVELOPMENT AS THE SHORTWAVE MOVES IN LATER. TODAY...BOTH SYNOPTIC MODELS AND CAM CONSENSUS SHOW THE FRONT EXITING THE ERN PERIPHERY OF THE CWFA IN 18-21Z TIMEFRAME. PROG SOUNDINGS FROM CLT/HKY INDICATE MODEST INSTABILITY STILL PRESENT IN THE NC PIEDMONT AT THAT TIME SO I ALLOWED POPS TO DROP OFF MORE QUICKLY IN THE WEST WHERE THE FROPA WILL OCCUR EARLIER...HOLDING ONTO LIKELY POPS EAST THRU PEAK HEATING. HIGHS TODAY HAVE BEEN HELD CLOSE TO A CONSENSUS OF RAW MODEL TEMPS...WITH CLOUDY CONDITIONS EXPECTED TO PERSIST MOST OF THE DAY. TONIGHT...LATEST COUPLE MODEL CYCLES HAVE DECLINED TO DRY THINGS OUT TOTALLY IN THE WAKE OF THE FRONT...RATHER FEATURING A FRONTAL WAVE DEVELOPING NEAR THE SC/GA COAST AND SOME RETURNING MOISTURE OVERNIGHT TONIGHT. THIS WAS HINTED AT FIRST BY THE EC A COUPLE DAYS AGO AND OTHER MODELS GRADUALLY BOUGHT INTO THIS IDEA. IN LIGHT OF THE TREND I ALLOWED POPS TO RISE AGAIN SOUTH/EAST OF I-85 TONIGHT. TEMPS WILL BE NOTICEABLY COOLER...ESPECIALLY IN THE MTNS WHERE THE COOL AND DRY AIR WILL ALREADY BE IN PLACE THIS EVENING. EVEN IN THE AFOREMENTIONED AREA OF MORE CLOUDS AND POPS LOWS IN THE MID TO UPPER 50S ARE EXPECTED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 AM MONDAY...MAJOR CHANGE IN THE FORECAST DURING THIS PERIOD AS ALL GUIDANCE POINTS TO AN UPPER LOW...THE REMNANTS OF KAREN...DETACHING FROM THE FULL LATITUDE TROF OVER THE ERN CONUS AND SLOWLY MOVING NORTH FROM THE GULF COAST ACROSS THE SERN CONUS. AT THE SFC...THE LOW PRESSURE AREA THAT IS THE REMNANTS OF KAREN DETACHES FROM THE COLD FRONT AND SLOWLY MOVES UP THE ATLANTIC COAST. WITH HIGH PRESSURE CENTERED OVER NEW ENGLAND IN A DAMMING CONFIGURATION...THE ELY LOW LEVEL FLOW AROUND THESE TWO SYSTEMS INCREASES AND BRINGS QUITE A BIT OF MOISTURE INTO THE AREA. ISENTROPIC LIFT WILL BE WEAK...BUT STRONG ENUF TO BRING CLOUDS AND PRECIP EAST TO WEST ACROSS THE CWFA TUE AND TUE NITE. THE FLOW BECOMES A LITTLE MORE NLY WED AND WED NITE AND MOISTURE SLOWLY PULLS OUT OF THE AREA AS THE LOW MOVES UP THE COAST. THIS MEANS DIMINISHING POP FROM WEST TO EAST WED AND WED NITE. FOR NOW...IT APPEARS PRECIP WILL BE LIGHT WITH THE BEST CHC ALONG AND SOUTH OF I-85 IN NE GA AND THE UPSTATE...AND OVER THE FOOTHILLS AND PIEDMONT IN NC. BREEZY TO POSSIBLY WINDY CONDITIONS ARE EXPECTED THRU THE PERIOD AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND HIGH. MUCH MORE CLOUDINESS IS EXPECTED AS WELL. THE COMBINATION OF CLOUDS AND PRECIP WILL BRING HIGHS GENERALLY IN THE LOW TO MID 60S...WITH SOME UPPER 60S POSSIBLE IN THE FAR WRN CWFA. LOWS IN THE LOW TO MID 50S TUE NITE FALL TO THE UPPER 40S TO LOWER 50S WED NITE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 310 AM MON...THE UPPER LOW FEATURED IN THE SHORT RANGE FCST SLOWLY MOVES EAST ACROSS NC/VA THEN OFF SHORE BY SUN. SOME WEAK RIDGING BUILDS IN BEHIND THE LOW AS SHORT WAVES MOVE UP THE RIDGE AND ACROSS THE OH VALLEY. AT THE SFC...THE COASTAL LOW CONTINUES ITS TREK UP THE EAST COAST AS THE DAMMING SFC HIGH WEAKENS. A DRIER N TO NWLY FLOW SETS UP AS THIS SYSTEM MOVES OUT OF THE AREA. THE GFS THEN TRIES TO BRINGS MOISTURE AND PRECIP BACK INTO THE AREA FROM THE NE BY THE WEEKEND AS ELY FLOW STRENGTHENS. THE CANADIAN AND THE ECMWF ARE MUCH WEAKER WITH THE FLOW AND ANY MOISTURE. THEREFORE...HAVE KEPT THE FCST DRY FOR NOW. HIGHS START OUT A LITTLE BELOW NORMAL THEN QUICKLY RISE TO NEAR NORMAL AND REMAIN NEARLY STEADY THRU THE NED OF THE PERIOD. LOWS START OUT NEAR NORMAL THEN RISE A FEW DEGREES BY THE EN OF THE PERIOD. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... AT KCLT...COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS AFTN...PRECEDED BY SHRA/TSRA. AN ORGANIZED LINE OF TSRA WILL MOVE THRU UPSTATE SC AND THE SRN NC PIEDMONT EARLY THIS AM. THIS LINE IS LIKELY TO BRING A PERIOD OF IFR CIGS/VSBY TO AFFECTED LOCATIONS...BUT TO HAVE A DIRECT IMPACT IT WILL HAVE TO BUILD ON ITS SRN END. WESTERLY GUSTS OF 15-20KT ALSO LIKELY ALONG THIS LINE. INDEED THE LINE MAY TRANSLATE NORTH OF THE FIELD...BUT CHANCES WARRANT A TEMPO. NONETHELESS...UNSTABLE ENVIRONMENT ALONG WITH UPPER ENERGY MAY ALLOW DISCRETE SHRA OR TSRA CAUSING BRIEF RESTRICTIONS UNTIL THE FRONT PUSHES THRU...WHEN VFR CONDITIONS RETURN. GENERALLY SOUTHERLY WINDS WILL FLIP TO NW FOLLOWING THE FROPA...BEFORE VEERING NE LATE IN THE PERIOD. ELSEWHERE...MORE OR LESS LIKE KCLT THOUGH TIMING EARLIER IN MOST REGARDS. MOST ORGANIZED CONVECTION WILL PUSH EAST OF KGSP/KGMU WITHIN THE FIRST COUPLE HRS OF THE TAF. STRATIFORM RAIN AND WIDELY SCATTERED HEAVY SHRA/TSRA WILL REMAIN IN SOME FORM OVERNIGHT. ANOTHER CLUSTER OF STORMS MAY AFFECT KAVL TOWARD DAYBREAK FOLLOWING AN EARLY MORNING LULL. VFR CONDITIONS SHOULD RETURN TO ALL SITES THIS AFTERNOON WITH THE WRN SITES POSSIBLY LOSING CIG ALTOGETHER BEFORE 00Z. OUTLOOK...DRY AND COOL HIGH PRESSURE BUILDS IN MON NITE AND CONTINUES THRU THE WEEK. RESTRICTIONS SHUD BE LIMITED TO MORNING MTN VALLEY FOG. CONFIDENCE TABLE... 07-13Z 13-19Z 19-01Z 01-07Z KCLT HIGH 86% HIGH 95% MED 76% HIGH 100% KGSP HIGH 94% MED 77% MED 79% HIGH 100% KAVL HIGH 93% MED 66% HIGH 100% HIGH 100% KHKY HIGH 88% MED 78% HIGH 94% HIGH 100% KGMU HIGH 93% HIGH 82% MED 78% HIGH 100% KAND HIGH 85% MED 77% HIGH 85% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...RWH NEAR TERM...WIMBERLEY SHORT TERM...RWH LONG TERM...RWH AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1145 PM CDT SUN OCT 6 2013 .UPDATE...FOR AVIATION. && .AVIATION... 06Z TAFS...COLD FRONT HAS MOVED THROUGH THE AREA WITH FEW SHRA LINGERING AROUND CSV. CSV WILL HAVE SHRA ENDING BY 09Z WITH SOME FOG AND LOW CLOUDS POSSIBLE THROUGH THE REST OF THE NIGHT. FOR BNA AND CKV...DRIER AIR AND CLEARING IS MOVING IN BEHIND THE FRONT...BUT SOME MVFR FOG MAY DEVELOP TOWARD DAYBREAK. HIGH PRESSURE WILL DOMINATE DAYTIME MONDAY...WITH EXCELLENT VSBY... SCT CU AROUND 4 KFT AND NNW WINDS NEAR 10KT. 13 && .PREV DISCUSSION... /ISSUED 721 PM CDT SUN OCT 6 2013/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REMOVE THE THROUGH LATE AFTERNOON WORDING AND TO TAILOR SHWRS PRESENTLY MAINLY E OF I-65 TO CONTINUE SLOWING MOVING EWD OUT OF MID STATE WITH SHWRS CONTINUING ACROSS THE PLATEAU COUNTIES ONLY GENERALLY AFTER MIDNIGHT. HAVE TAILORED SKY CONDITIONS ALSO TO REFLECT DECREASING CLOUDINESS W TO E ACROSS THE MID STATE AS THE NIGHT TIME HRS PROGRESS. CURRENT TEMPS IN LINE WITH FORECASTED LOW VALUES AS OF THIS TIME...THUS NO ADJUSTMENTS MADE TO OVERNIGHT LOW VALUES AS OF THIS TIME. 31 PREV DISCUSSION... /ISSUED 511 PM CDT SUN OCT 6 2013/ UPDATE... HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO INTRODUCE A THROUGH THE LATE AFTERNOON HOURS GROUPING ALL COUNTIES TO DEAL WITH CURRENT AND EXPECTED SHORT TERM PROGRESSION OF SHWRS AND ISO TSTMS W TO E ACROSS MID STATE. TEMPS SHOULD FALL ACROSS THE ENTIRE MID STATE INTO THE UPPER 50S BY THE LATE AFTERNOON HRS. ALSO. 31 PREV DISCUSSION.../ISSUED 213 PM CDT SUN OCT 6 2013/ DISCUSSION...SURFACE FRONT HAS MADE IT EAST OF NASHVILLE, WITH A BROKEN LINE OF MODERATE TO HEAVY SHOWERS OCCURRING ALONG THE BOUNDARY. HRRR DOING A REASONABLE JOB WITH ONGOING ACTIVITY, AND THE SHORT-RANGE MODEL SHOWS NUMEROUS CELLS LASTING WELL PAST 00Z. SIGNIFICANTLY COOLER AIR AND LOWER DEW POINTS ARE OBVIOUSLY RUSHING IN BEHIND THE FRONT, EVEN AS SCATTERED SHOWERS CONTINUE DEVELOPING IN THE COLD POOL. EXPECT MOST OF THE ACTIVITY TO MOVE EAST OF THE AREA BY 06Z, WITH SHOWERS EXITING THE PLATEAU BY 12Z. A BROAD RIDGE OF HIGH PRESSURE WILL QUICKLY BUILD IN AND DRY OUT THE ATMOSPHERE AND KEEP A COOLER AIR MASS LOCKED IN PLACE OVER MIDDLE TENNESSEE THE REMAINDER OF THE WEEK. NO PRECIPITATION IS EXPECTED FROM TOMORROW THROUGH THE END OF THE 7-DAY FORECAST PERIOD. ROSE && .OHX WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
239 PM CDT MON OCT 7 2013 .SHORT TERM.../NOW THROUGH TUESDAY NIGHT/...AS MR. RODGERS WOULD SAY...IT IS A BEAUTIFUL DAY IN THE NEIGHBORHOOD...AND IT WILL REMAIN BEAUTIFUL THROUGH THE SHORT TERM PERIOD. MID LEVEL RIDGE MOVES INTO WESTERN TEXAS AND SURFACE RIDGE PARKS ITSELF OVER SOUTH TEXAS TONIGHT. ATMOSPHERE REMAINS VERY DRY WITH THE LIGHT OFFSHORE FLOW CONTINUING INTO TUESDAY BEFORE VEERING SOUTHEAST TUESDAY NIGHT. WARM DAYS AND COOL NIGHTS CONTINUE UNDER THE CLEAR SKIES AND LOW DEW POINT AIR. MODEL TEMPERATURES GUIDANCE REMAINS CONSISTENT BUT WILL TREND SLIGHTLY LOWER FOR OVERNIGHT LOWS AS EXCELLENT RADIATIONAL COOLING TAKES PLACE. A FEW DEGREES WARMER ON TUESDAY WITH FORECAST NUMBERS NOT STRAYING TO FAR GUIDANCE. AS WE HEAD INTO TUESDAY NIGHT SOUTHEAST WINDS RETURN ALBEIT WEAK. SOMEWHAT MODEST LOW LEVEL MOISTURE ADVECTION IN THE LOWER 3000 FEET...LIGHT WINDS AND MOSTLY CLEAR SKIES COULD RESULT IN SOME PATCHY GROUND FOG BY SUNRISE WEDNESDAY. UNSURE IF MOISTURE ADVECTION WILL BE SUFFICIENT FOR DENSE FOG FORMATION BUT VISIBILITIES COULD LOWER BELOW 1 MILE IN THE MORE FAVORED LOCATIONS IN THE KHBV KBKS AREAS. OVERNIGHT NIGHT LOWS WILL BE WARMER BUT STILL BELOW GUIDANCE VALUES WITH THE WEAK RETURN FLOW NOT ADDING MUCH WARM AIR ADVECTION AT THIS TIME. ENJOY IT NOW A/C MAY HAVE TO CRANKED UP SOON. .LONG TERM.../WEDNESDAY THROUGH MONDAY NIGHT/... UPPER LEVEL TROUGH OVER THE WESTERN U.S. WILL DEPEND AND LIFT TO THE NORTHEAST ACROSS THE FOUR CORNERS REGION THURSDAY INTO FRIDAY. AT THE SURFACE...STRONG SURFACE LEE TROUGH DEVELOPS ENHANCING THE SOUTHEAST FLOW FROM THE CENTRAL PLAINS SOUTHWARD INTO SOUTH TEXAS REGION. EXPECT THIS BREEZE AFTERNOON THROUGH THURSDAY. WARM FRONT OVER THE SOUTHERN GULF WILL LIFT N/NW AS RIDGE BUILDS ACROSS THE REGION. THIS SURFACE LOW WILL SURGE DEEP LAYER MOISTURE FROM THE SOUTHERN GULF INTO THE CWA THURSDAY AND FRIDAY. THE 1000 TO 500 MB RH VALUES SHOWS AN INCREASE BETWEEN 60 TO 70 PERCENT THROUGH THE WEEKEND AS THE UPPER LEVEL LOW INTERACTS WITH RIDGE OVER SOUTH TEXAS. THIS WILL ENHANCE THE CHANCE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE CWA FRIDAY AND INTO THE WEEKEND. DECIDED TO INCREASE POP FORECAST TO 20 PERCENT AT THIS TIME SINCE THERE IS GOOD AGREEMENT AND CONSISTENCY WITH THE GFS/ECMWF MODEL RUN. THE COASTAL COUNTIES ARE MORE FAVORABLE TO RECEIVE SOME RAINFALL FROM THIS MOISTURE SURGE. DAYTIME HIGHS WILL GRADUALLY WARM TO THE MID 90S THROUGH THE END OF THE LONG TERM FORECAST. BY NEXT WEEK...GULF MOISTURE WILL RAP AROUND THE PERIPHERY OF THE HIGH AND ENHANCE THUNDERSTORM ACTIVITY ALONG THE SIERRA MADRE AND CENTRAL TEXAS. THIS AREA OF CONVECTION WILL CONTINUE INTO TUESDAY UNTIL THE NEXT UPPER TROUGH DEEPENS PUSHING ALL THE MOISTURE OUT OF THE AREA POSSIBLY BY MID WEEK. && .MARINE...NOW THROUGH TUESDAY NIGHT...EXCELLENT MARINE CONDITIONS THROUGH TUESDAY NIGHT WITH SURFACE HIGH PRESSURE SETTLING OVER THE COASTAL WATERS. LIGHT NORTHEAST WINDS TONIGHT TO VEER EAST TUESDAY THEN SOUTHEAST TUESDAY NIGHT. SEAS CONTINUE TO FALL TONIGHT LOWERING TO 2 FEET OR LESS TUESDAY. WEDNESDAY THROUGH MONDAY NIGHT... SOUTHEAST WINDS RETURN WEDNESDAY AS THE HIGH PRESSURE BUILDS ACROSS THE AREA. THIS SOUTHEAST FLOW WILL INCREASE THURSDAY INTO FRIDAY AND BUILD SEAS BELOW ADVISORY CRITERIA THROUGH THE END OF THE WEEK. AN AREA OF LOW PRESSURE WILL MOVE NORTHWARD INTO THE MARINE ZONES THURSDAY INTO FRIDAY ENHANCING THE MOISTURE CONTENT IN THE AREA. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE SATURDAY THROUGH MONDAY OVER THE GULF WATERS AS THE ABUNDANT MOISTURE WILL BE HIGHEST OVER THE MARINE ZONES. NO SCA OR SCEC EXPECTED AT THIS TIME THROUGH MONDAY. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 60 87 68 88 / 0 0 0 0 BROWNSVILLE 59 88 66 90 / 0 0 0 0 HARLINGEN 56 89 64 90 / 0 0 0 0 MCALLEN 59 91 66 91 / 0 0 0 0 RIO GRANDE CITY 58 91 65 92 / 0 0 0 0 SOUTH PADRE ISLAND 68 84 74 87 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 59/67
AREA FORECAST DISCUSSION...CORRECTED GRAMMAR
NWS NORTH PLATTE NE
304 AM CDT WED OCT 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 232 AM CDT WED OCT 9 2013 IN RESPONSE TO STRENGTHENING WINDS ALOFT...SURFACE LOW PRESSURE HAS FORMED ACROSS ERN COLORADO SETTING UP AN STATIONARY FRONT AND INVERTED TROF FROM KOGA TO KVTN. A STRONG SOUTHWESTERLY LOW LEVEL JET SOUTH OF THIS FRONT WILL VEER OFF LATER THIS MORNING ALLOWING THE FRONT TO DROP SOUTH THIS AFTERNOON. THIS WILL PLACE MOST OF THE FCST AREA IN EAST OR NORTHEAST WINDS AND COOL AIR BY 21Z. THE MAX TEMPERATURE FORECAST CALLS FOR HIGHS IN THE 60S TO LOWER 70S BEHIND THE FRONT AND MID 70S ALONG AND AHEAD OF THE FRONT. THIS IS VERY CLOSE TO THE GEMREG...NAM12...HRRR AND RAP13 MODELS. THERE IS STILL SOME SNOW ON THE GROUND ACROSS NORTHWEST SHERIDAN COUNTY WHICH COULD KEEP HIGHS IN THE UPPER 50S. THE GFS AND RAP MODELS SHOW A BREAK IN THE CIRRUS TODAY. THE GFS SHOWS ANOTHER BATCH MOVING IN TONIGHT. THE MAIN LIMITATION ON HIGH TEMPERATURES TODAY WOULD APPEAR TO BE VERTICAL MIXING AND WEAK COLD AIR ADVECTION BEHIND THE SFC FRONT. OTHERWISE LIGHT WINDS ARE EXPECTED TODAY AND TONIGHT WITH THE FRONT BASICALLY ON TOP OF THE FORECAST AREA. A MULTIMODEL ENSEMBLE FORECAST SHOWS DEW POINTS RISING INTO THE MID AND UPPER 40S THIS AFTERNOON AND TONIGHT. THIS SHOULD KEEPS LOWS IN THE 40S TO LOWER 50S TONIGHT. SOME STRATUS MAY DEVELOP BEHIND THE FRONT ACROSS THE NORTHWEST THIS AFTERNOON AS A RESULT OF MIXING PROCESSES TO AROUND 800 MB. THESE CLOUDS DISSIPATE WITH THE LOSS OF DAYTIME HEATING TONIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 232 AM CDT WED OCT 9 2013 AN ACTIVE PERIOD...WITH TWO WEATHER MAKERS EXPECTED TO AFFECT WESTERN AND NORTH CENTRAL NEBRASKA. HIGH CONFIDENCE EXISTS WITH THE FIRST SYSTEM TO MOVE THROUGH THURSDAY NIGHT INTO FRIDAY...WITH NEARLY ALL GFS ENSEMBLE MEMBERS IN AGREEMENT ON THE TRACK OF THE NEGATIVELY TILTED 500 MB TROUGH. CONFIDENCE IS LOWER WITH THE SECOND SYSTEM SET TO ARRIVE EARLY NEXT WEEK. MORE ON THE SECOND SYSTEM LATER. AS MENTIONED...ENSEMBLES AND OPERATIONAL MODELS ARE IN VERY GOOD AGREEMENT WITH THE TRACK AND TIMING OF THE SYSTEM TO AFFECT THE REGION THURSDAY NIGHT INTO FRIDAY...AND INGREDIENTS FOR AN EPISODE OF SEVERE THUNDERSTORMS SEEMS INCREASINGLY FAVORABLE. ALOFT...A SIGNIFICANT NEGATIVELY TILTED SHORTWAVE TROUGH WILL QUICKLY TRACK FROM THE FOUR CORNERS AREA TO WESTERN NEBRASKA THURSDAY AFTERNOON THROUGH FRIDAY MORNING. AHEAD OF THIS FEATURE...A DEEPENING SURFACE LOW ACROSS EASTERN COLORADO THURSDAY AFTERNOON WILL HELP DRAW INCREASINGLY MOIST AIR NORTH FROM THE SOUTHERN PLAINS. BY EARLY EVENING MIXED LAYER DEW POINTS AT 500 METERS ARE IN THE 50 TO 55F DEGREE RANGE...WITH 850 MB DEW POINTS AT LEAST 10C IN MOST OPERATIONAL MODELS. IT APPEARS THAT THE ARRIVAL OF STRONG FORCING/COOLING ALOFT WILL COINCIDE WITH PEAK HEATING ACROSS EASTERN COLORADO...WHERE STORMS WILL FORM RAPIDLY ALONG AN ADVANCING PACIFIC COLD FRONT. THE 09/00Z NAM MODEL SUGGESTS A PLUME OF STEEP LOW LEVEL LAPSE RATES WILL EXIST TO THE EAST OF THESE STORMS ACROSS WESTERN NEBRASKA AND WESTERN KANSAS. THESE STEEP LOW LEVEL LAPSE RATES...IN COMBINATION WITH STEEP MID LEVEL LAPSE RATES AND INCREASINGLY MOIST AIR...SHOULD ENSURE AN ENVIRONMENT FAVORABLE FOR THESE THUNDERSTORMS TO SPREAD EAST. UPPER AIR FORECAST SOUNDING AT NORTH PLATTE BY MID EVENING INDICATES WINDS VEERING FROM SOUTHEAST IN THE LOWEST LEVELS...TO SOUTH-SOUTHWEST IN THE MID LEVELS...AND SOUTHWEST IN THE UPPER LEVELS. THE TREND HAS BEEN FOR A BIT MORE DIRECTIONAL SHEAR...AS WINDS VEER A BIT MORE IN THE MID LEVELS THAN PREVIOUS MODEL RUNS WERE INDICATING. THIS COULD HELP KEEP STORMS A BIT MORE DISCRETE...BUT OVERALL IT STILL APEARS THAT A SQUALL LINE WITH WIND DAMAGE POTENTIAL WILL EVENTUALLY EVOLVE DURING THE EVENING ALONG THE EASTWARD ADVANCING PACIFIC COLD FRONT. IF STORMS WOULD HAPPEN TO STAY A BIT MORE DISCRETE...THEN A TORNADO POTENTIAL CANNOT BE RULED OUT...AS STORMS SPREAD EAST INTO AN AREA OF HIGH HELICITY VALUES. IN FACT...DO TO THE STRONG LOWER TROPOSPHERIC WINDS AND DIRECTIONAL SHEAR...0 TO 3 KM HELICITY VALUES INCREASE TO NEAR 500 M2/S2 BY MID EVENING THURSDAY NIGHT AT NORTH PLATTE. WHILE THE ENVIRONMENT ACROSS WESTERN/SOUTHWEST NEBRASKA LOOKS FAVORABLE FOR SEVERE THUNDERSTORMS...THE EASTWARD EXTENT OF THIS ENVIRONMENT IS LIMITED. AT THIS TIME IT APPEARS THE SEVERE THREAT WITH THE STORMS MAY DECREASE TO NEAR ZERO BY THE TIME THE STORMS MOVE INTO THE EASTERN PORTIONS OF THE FORECAST AREA AROUND BARTLETT AND ONEILL. AFTER THE SEVERE POTENTIAL THURSDAY EVENING...THE NEXT CONCERN IS WIND POTENTIAL ON THE SOUTHERN SIDE OF THE SYSTEM LATE THURSDAY NIGHT INTO FRIDAY. 09/00Z NAM DEEPENS THE SURFACE LOW TO NEAR 989 MB ACROSS NORTHERN SOUTH DAKOTA BY NOONTIME FRIDAY. 500 METER WIND SPEEDS INCREASE TO AROUND 33 KTS FOR A TIME FRIDAY MORNING...WHICH COULD SUPPORT NEAR WIND ADVISORY SPEEDS AT THE SURFACE. WINDS DECREASE DURING THE AFTERNOON AS THE LOW PRESSURE SYSTEM LIFT NORTH AWAY FROM THE AREA. THE WEEKEND IS LOOKING NICE...AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA AHEAD OF THE NEXT SYSTEM SET TO ARRIVE MONDAY. THE 09/00Z GFS ENSEMBLE MEAN IS NOW SHOWING THIS SYSTEM POTENTIALLY COMING THOUGH AS A CLOSED SYSTEM...LIKE THE 08/12Z AND 09/00Z RUNS OF THE ECMWF SHOW. WILL TREND THE FORECAST IN THE DIRECTION OF THE ECMWF...AS IT HAS THE SUPPORT OF THE GFS ENSEMBLE. THIS WOULD BRING A GOOD CHANCE FOR RAIN MONDAY AND MONDAY NIGHT TO THE AREA. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 555 PM CDT TUE OCT 8 2013 VFR FLIGHT CONDS ARE EXPECTED AT BOTH THE KLBF AND KVTN TERMINALS OVER THE NEXT 24 HOURS. CIGS WILL BE AON 25000 FT AGL. WINDS AT THE KLBF TERMINAL WILL BE FROM THE EAST OR SOUTHEAST AT AROUND 10 KTS. FOR THE KVTN TERMINAL...WINDS WILL BE VARIABLE AT UNDER 10 KTS TONIGHT AND WEDS EVENING...WITH SERLY WINDS AROUND 10 KTS EXPECTED WEDNESDAY MORNING AND WEDNESDAY AFTERNOON. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
234 AM CDT WED OCT 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 232 AM CDT WED OCT 9 2013 IN RESPONSE TO STRENGTHENING WINDS ALOFT...SURFACE LOW PRESSURE HAS FORMED ACROSS ERN COLORADO SETTING UP AN STATIONARY FRONT AND INVERTED TROF FROM KOGA TO KVTN. A STRONG SOUTHWESTERLY LOW LEVEL JET SOUTH OF THIS FRONT WILL VEER OFF LATER THIS MORNING ALLOWING THE FRONT TO DROP SOUTH THIS AFTERNOON. THIS WILL PLACE MOST OF THE FCST AREA IN EAST OR NORTHEAST WINDS AND COOL AIR BY 21Z. THE MAX TEMPERATURE FORECAST CALLS FOR HIGHS IN THE 60S TO LOWER 70S BEHIND THE FRONT AND MID 70S ALONG AND AHEAD OF THE FRONT. THIS IS VERY CLOSE TO THE GEMREG...NAM12...HRRR AND RAP13 MODELS. THERE IS STILL SOME SNOW ON THE GROUND ACROSS NORTHWEST SHERIDAN COUNTY WHICH COULD KEEP HIGHS IN THE UPPER 50S. THE GFS AND RAP MODELS SHOW A BREAK IN THE CIRRUS TODAY. THE GFS SHOWS ANOTHER BATCH MOVING IN TONIGHT. THE MAIN LIMITATION ON HIGH TEMPERATURES TODAY WOULD APPEAR TO BE VERTICAL MIXING AND WEAK COLD AIR ADVECTION BEHIND THE SFC FRONT. OTHERWISE LIGHT WINDS ARE EXPECTED TODAY AND TONIGHT WITH THE FRONT BASICALLY ON TOP OF THE FORECAST AREA. A MULTIMODEL ENSEMBLE FORECAST SHOWS DEW POINTS RISING INTO THE MID AND UPPER 40S THIS AFTERNOON AND TONIGHT. THIS SHOULD KEEPS LOWS IN THE 40S TO LOWER 50S TONIGHT. SOME STRATUS MAY DEVELOP BEHIND THE FRONT ACROSS THE NORTHWEST THIS AFTERNOON AS A RESULT OF MIXING PROCESSES TO AROUND 800 MB. THESE CLOUDS DISSIPATE WITH THE LOSS OF DAYTIME HEATING TONIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 232 AM CDT WED OCT 9 2013 AN ACTIVE PERIOD...WITH TWO WEATHER MAKERS EXPECTED TO AFFECT WESTERN AND NORTH CENTRAL NEBRASKA. HIGH CONFIDENCE EXISTS WITH THE FIRST SYSTEM TO MOVE THROUGH THURSDAY NIGHT INTO FRIDAY...WITH NEARLY ALL GFS ENSEMBLE MEMBERS IN AGREEMENT ON THE TRACK OF THE NEGATIVELY TILTED 500 MB TROUGH. CONFIDENCE IS LOWER WITH THE SECOND SYSTEM SET TO ARRIVE EARLY NEXT WEEK. MORE ON THE SECOND SYSTEM LATER. AS MENTIONED...ENSEMBLES AND OPERATIONAL MODELS ARE IN VERY GOOD AGREEMENT WITH THE TRACK AND TIMING OF THE SYSTEM TO AFFECT THE REGION THURSDAY NIGHT INTO FRIDAY...AND INGREDIENTS FOR AN EPISODE OF SEVERE THUNDERSTORMS SEEMS INCREASINGLY FAVORABLE. ALOFT...A SIGNIFICANT NEGATIVELY TILTED SHORTWAVE TROUGH WILL QUICKLY TRACK FROM THE FOUR CORNERS AREA TO WESTERN NEBRASKA THURSDAY AFTERNOON THROUGH FRIDAY MORNING. AHEAD OF THIS FEATURE...A DEEPENING SURFACE LOW ACROSS EASTERN COLORADO THURSDAY AFTERNOON WILL HELP DRAW INCREASINGLY MOIST AIR NORTH FROM THE SOUTHERN PLAINS. BY EARLY EVENING MIXED LAYER DEW POINTS AT 500 METERS ARE IN THE 50 TO 55F DEGREE RANGE...WITH 850 MB DEW POINTS AT LEAST 10C IN MOST OPERATIONAL MODELS. IT APPEARS THAT THE ARRIVAL OF STRONG FORCING/COOLING ALOFT WILL COINCIDE WITH PEAK HEATING ACROSS EASTERN COLORADO...WHERE STORMS WILL FORM RAPIDLY ALONG AN ADVANCING PACIFIC COLD FRONT. THE 09/00Z NAM MODEL SUGGESTS A PLUME OF STEEP LOW LEVEL LAPSE RATES WILL EXIST TO THE EAST OF THESE STORMS ACROSS WESTERN NEBRASKA AND WESTERN KANSAS. THESE STEEP LOW LEVEL LAPSE RATES...IN COMBINATION WITH STEEP MID LEVEL LAPSE RATES AND INCREASINGLY MOIST AIR...SHOULD ENSURE AN ENVIRONMENT FAVORABLE FOR THESE THUNDERSTORMS TO SPREAD EAST. UPPER AIR FORECAST SOUNDING AT NORTH PLATTE BY MID EVENING INDICATES WINDS VEERING FROM SOUTHEAST IN THE LOWEST LEVELS...TO SOUTH-SOUTHWEST IN THE MID LEVELS...AND SOUTHWEST IN THE UPPER LEVELS. THE TREND HAS BEEN FOR A BIT MORE DIRECTIONAL SHEAR...AS WINDS VEER A BIT MORE IN THE MID LEVELS THAN PREVIOUS MODEL RUNS WERE INDICATING. THIS COULD HELP KEEP STORMS A BIT MORE DISCRETE...BUT STILL APPEARS THAT OVERALL A SQUALL LINE WITH WIND DAMAGE POTENTIAL WILL EVENTUALLY EVOLVE DURING THE EVENING ALONG THE EASTWARD ADVANCING PACIFIC COLD FRONT. IF STORMS WOULD HAPPEN TO STAY A BIT MORE DISCRETE...THEN A TORNADO POTENTIAL CANNOT BE RULED OUT...AS STORMS SPREAD EAST INTO AN AREA OF HIGH HELICITY VALUES. IN FACT...DO TO THE STRONG LOWER TROPOSPHERIC WINDS AND DIRECTIONAL SHEAR...0 TO 3 KM HELICITY VALUES INCREASE TO NEAR 500 M2/S2 BY MID EVENING THURSDAY NIGHT AT NORTH PLATTE. WHILE THE ENVIRONMENT ACROSS WESTERN/SOUTHWEST NEBRASKA LOOKS FAVORABLE FOR SEVERE THUNDERSTORMS...THE EASTWARD EXTENT OF THIS ENVIRONMENT IS LIMITED. AT THIS TIME IT APPEARS THE SEVERE THREAT WITH THE STORMS MAY DECREASE TO NEAR ZERO BY THE TIME THE STORMS MOVE INTO THE EASTERN PORTIONS OF THE FORECAST AREA AROUND BARTLETT AND ONEILL. AFTER THE SEVERE POTENTIAL THURSDAY EVENING...THE NEXT CONCERN IS WIND POTENTIAL ON THE SOUTHERN SIDE OF THE SYSTEM LATE THURSDAY NIGHT INTO FRIDAY. 09/00Z NAM DEEPENS THE SURFACE LOW TO NEAR 989 MB ACROSS NORTHERN SOUTH DAKOTA BY NOONTIME FRIDAY. 500 METER WIND SPEEDS INCREASE TO AROUND 33 KTS FOR A TIME FRIDAY MORNING...WHICH COULD SUPPORT NEAR WIND ADVISORY SPEEDS AT THE SURFACE. WINDS DECREASE DURING THE AFTERNOON AS THE LOW PRESSURE SYSTEM LIFT NORTH AWAY FROM THE AREA. THE WEEKEND IS LOOKING NICE...AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA AHEAD OF THE NEXT SYSTEM SET TO ARRIVE MONDAY. THE 09/00Z GFS ENSEMBLE MEAN IS NOW SHOWING THIS SYSTEM POTENTIALLY COMING THOUGH AS A CLOSED SYSTEM...LIKE THE 08/12Z AND 09/00Z RUNS OF THE ECMWF SHOW. WILL TREND THE FORECAST IN THE DIRECTION THE ECMWF...AS IT HAS THE SUPPORT OF THE GFS ENSEMBLE. THIS WOULD BRING A GOOD CHANCE FOR RAIN MONDAY AND MONDAY NIGHT TO THE AREA. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 555 PM CDT TUE OCT 8 2013 VFR FLIGHT CONDS ARE EXPECTED AT BOTH THE KLBF AND KVTN TERMINALS OVER THE NEXT 24 HOURS. CIGS WILL BE AON 25000 FT AGL. WINDS AT THE KLBF TERMINAL WILL BE FROM THE EAST OR SOUTHEAST AT AROUND 10 KTS. FOR THE KVTN TERMINAL...WINDS WILL BE VARIABLE AT UNDER 10 KTS TONIGHT AND WEDS EVENING...WITH SERLY WINDS AROUND 10 KTS EXPECTED WEDNESDAY MORNING AND WEDNESDAY AFTERNOON. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CLB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
324 AM EDT WED OCT 9 2013 .SYNOPSIS... UNSETTLED WEATHER WILL PERSIST INTO THURSDAY...FOLLOWED BY SOME GRADUAL IMPROVEMENT OF WEATHER CONDITIONS FRIDAY THROUGH THE WEEKEND...AND INTO EARLY NEXT WEEK. AREA OF LOW PRESSURE WILL MEANDER JUST OFFSHORE FROM THE CAROLINA COASTS TODAY THROUGH THE END OF THIS WEEK...BEFORE FINALLY TRACKING AWAY FROM THE AREA THIS WEEKEND. THE NEXT COLD FRONT WILL PUSH ACROSS THE AREA NEXT TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...UPPER LEVEL LOW PRESSURE ACROSS THE EASTERN CAROLINAS SHOULD LIFT INTO NORTHERN NORTH CAROLINA BY TONIGHT. AT THE SURFACE LOW PRESSURE ABOUT 200 MILES EAST OF SAVANNAH WILL WEAKEN AS IT MOVES NORTHEASTWARD TO A POSITION ABOUT 200 MILES EAST OF MYRTLE BEACH LATE TONIGHT. THE GRADIENT BETWEEN THIS LOW AND STRONG CANADIAN HIGH PRESSURE OVER NORTHERN NEW ENGLAND WILL PRODUCE BREEZY NORTH WINDS TODAY...DIMINISHING SOMEWHAT TONIGHT. MODELS HAVE BEEN PLAYING CATCH-UP WITH THE LIMITED DISTRIBUTION OF ISENTROPIC LIFT AND SUBSEQUENT RAINFALL AROUND OUR COASTAL LOW THIS MORNING. RADAR ECHOES ARE GENERALLY MOVING SLOWLY WESTWARD AND NORTHWESTWARD...AND MATCHING THAT UP WITH MODEL WIND PROFILES SHOWS PRECIPITATION LIKELY IS BEING GENERATED ALONG THE 310K-315K ISENTROPIC SURFACES WHICH ARE LOCATED 10K-15KFT ALOFT. THIS REGION OF LIFT SHOULD WEAKEN AND SHIFT NORTHWARD WITH TIME TODAY...LEAVING SURPRISINGLY LITTLE PRECIPITATION FOR MOST OF MY FORECAST AREA. IN FACT THE ONLY AREAS I HAVE CONFIDENCE IN MEASURABLE RAINFALL THIS MORNING ARE NEW HANOVER AND PENDER COUNTIES...POTENTIALLY SPREADING BACK A LITTLE DEEPER IN SOUTHEASTERN NORTH CAROLINA BY MID-MORNING AS ATLANTIC MOISTURE PIVOTS BEHIND THE 700 MB LOW LIFTING NORTH ALONG THE NC COASTLINE. BY THIS AFTERNOON THE BULK OF THE FORECAST AREA WILL BE UNDER ISENTROPIC DOWNGLIDE...WITH BREAKS OPENING IN THE CLOUD COVER ACROSS SOUTH CAROLINA. AN OTHERWISE UNSEASONABLY CHILLY AIRMASS SHOULD STILL KEEP TEMPERATURES FROM SPIKING TOO HIGH DESPITE THE LACK OF PRECIPITATION...AND I AM EXPECTING TEMPERATURES TO TOUCH 70 NEAR THE SANTEE RIVER...WITH UPPER 60S ACROSS THE REMAINDER OF NE SOUTH CAROLINA. ACROSS SE NORTH CAROLINA MID 60S ARE EXPECTED...ALTHOUGH ELIZABETHTOWN AND BURGAW MIGHT BE ON THE LOWER END OF THAT RANGE IF DENSE CLOUDS OR LIGHT RAIN CONTINUES INTO THE AFTERNOON. FOR TONIGHT THERE IS STILL PLENTY OF MOISTURE BELOW 700 MB BUT PREVAILING ISENTROPIC DOWNGLIDE BEHIND THE DEPARTING MID-LEVEL LOW SHOULD JUST ABOUT END PRECIPITATION CHANCES. I WILL STILL CARRY A 20 POP THROUGH THE EVENING JUST IN CASE SOME PATCHY LIGHT RAIN REMAINS. A SUFFICIENT DEPTH OF LOW CLOUDS SHOULD REDEVELOP ACROSS SE NORTH CAROLINA TO ADD AREAS OF DRIZZLE TO THE FORECAST AS WELL. LOW TEMPERATURES ARE TENTATIVELY PROGGED TO REACH THE MID 50S FOR MOST AREAS...ALTHOUGH THE AMOUNT OF LINGERING CLOUD COVER IS A BIG QUESTION MARK. IF SKIES CLEAR ACROSS THE SC PEE DEE REGION WINDS COULD PARTIALLY DECOUPLE WITH LOWS FALLING TOWARD 50. IF ENOUGH CLOUDS REMAIN TO KEEP WINDS FROM DECOUPLING THEN MID 50S WILL OCCUR...AS IS CURRENTLY FORECAST AREA-WIDE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY...THE MAIN WX FEATURE AFFECTING THE FA DURING THIS TIME PERIOD INCLUDES THE UPPER LOW...THAT NEARLY BECOMES CUTOFF. MODELS IE. GFS NAM EUROPEAN CANADIAN JUST TO NAME A FEW...ARE AMAZINGLY SIMILAR TO ONE ANOTHERS SOLUTIONS. THE RATHER LARGE AMPLIFIED UPPER RIDGING WILL AFFECT THE EASTERN U.S. THRUOUT THIS TIME PERIOD. ONE WOULD THINK OF NEAR NORMAL OR HIGHER THERE OF WOULD AFFECT THE FA DURING THIS TIME PERIOD. HOWEVER...THIS IS NOT THE CASE. MODELS AGAIN AMAZINGLY SIMILAR TO ONE ANOTHER WITH RESPECT TO THE EVOLUTION OF THE UPPER CLOSED LOW CENTERED ACROSS THE EASTERN CAROLINAS AND/OR VIRGINIA. IT REMAINS RATHER DOCILE AND STATIONARY UNDERNEATH THE RATHER LARGE AMPLIFIED MID-LEVEL TROUGHING. AREAS THAT WILL OBSERVE THE BEST CHANCE...AND THE HIGHER POPS...WILL LIE BASICALLY IN AN EASTERN SEMI-CIRCLE AROUND THE UPPER LOW...FROM N-NE TO SE-S...TURNING CLOCKWISE. THE BETTER TRANSPORT OF MOISTURE... FEEDING FROM OFF THE ATL OCEAN...IS EXHIBITED QUITE WELL FROM THE VARIOUS MODELS WITH RESPECT TO TIME-HEIGHTS. THIS SEMI-CIRCLE WILL REMAIN OUT OF RANGE FROM THE ILM CWA...ALTHOUGH WRAP AROUND MOISTURE CIRCULATING THE UPPER LOW WILL CONTINUE TO PROVIDE MORE CLOUDINESS THEN SUN OR MOON SHINE. MODEL SOUNDINGS INDICATE THE DEEPER MOISTURE WILL REMAIN IN THE SFC TO 600 MB LAYER DURING THIS TIME PERIOD... WITH ONLY WEAK DYNAMICS FROM VARIOUS MID-LEVEL VORTS ROTATING AROUND THE UPPER LOW...THEREBY AIDING AND INCREASING WEAK FORCING/UVVS. OVERALL...WILL HAVE A RANGE OF POPS ACROSS THE FA...WITH THE HIGHER POPS TO OCCUR ACROSS THE N-NE PORTIONS OF THE FA AND DECREASING QUITE DRAMATICALLY AS YOU PROGRESS TO THE S-SW PORTIONS OF THE FA. AS FOR MAX/MIN TEMPS THRUOUT THE SHORT TERM...STAYED CLOSER TO THE COOLER GFS MOS OUTPUT. COULD POSSIBLY GO EVEN LOWER BY A FEW DEGREES AS OVERCAST AND PCPN CONDITIONS AFFECT THE FA. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY...THE NEMESIS UPPER LOW UNDERNEATH THE STRONG UPPER RIDGING...TO REMAIN THE PROBLEM CHILD DURING THIS PERIOD. AS ONE WOULD EXPECT...MODELS NO LONGER SIMILAR WITH THEIR RESPECTIVE SOLUTIONS. MODELS DO HOWEVER...TRANSITION THE UPPER CLOSED LOW INTO AN OPEN S/W TROF BY LATE SUNDAY OR EARLY MONDAY. MODELS SLOWLY TRACK IT TO THE EAST ALLOWING DRIER AIR...UPSTREAM FROM THE W-NW...TO WORK ITS WAY ACROSS THE FA AT ALL LEVELS. IN ADDITION SUBSIDENCE AND NVA ALOFT...WILL PLACE A LID ON ANY MID-UPPER LEVEL CLOUD DEVELOPMENT AND DIMINISH THE PCPN THREAT. THIS OVERALL LOWERED CLOUDINESS DEVELOPMENT AND PCPN FORMATION WILL BE SHORT-LIVED AS MODELS INDICATE THE APPROACH OF A SFC COLD FRONT FROM THE WEST DURING TUESDAY. WILL INDICATE A LOW POP FOR LATE TUE NIGHT. AS FOR MAX/MIN TEMPS THIS PERIOD...STAYED CLOSER TO THE GFS MOS OUTPUT...WITH 80+ MAXES POSSIBLE EARLY NEXT WEEK. MAX/MIN TEMPS THIS TIME PERIOD WILL IN GENERAL BE AT OR HIGHER THAN CLIMO BY A CATEGORY OR 2. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...EXPECT PERIODS OF RAIN OVERNIGHT...MAINLY ALONG THE COAST...ALONG WITH MVFR/IFR CIGS. HIGHEST CONFIDENCE FOR IFR IS AT KILM WHERE CIGS BELOW 1KFT HAVE BEEN MOST PERSISTENT. MVFR CIGS SHOULD PREVAIL AT CRE/MYR/FLO/LBT. THE BEST-INITIALIZED MODEL APPEARS TO BE THE 04Z RUC WHICH CAPTURES SURFACE TEMPERATURE/ DEWPOINT TRENDS AND CEILING HEIGHTS THE BEST. THE SFC LOW OFFSHORE WILL GRADUALLY MOVE UP THE ATLANTIC COAST TODAY...AND WITH IT THE BEST LIFT WILL BE DISPLACED TO OUR NORTH. WILL KEEP A MENTION OF VCSH IN THE FCST...BUT IT APPEARS PCPN CHANCES DIMINISH FOR MUCH OF OUR AREA BY THE AFTN. THE LOW-LEVEL INVERSION SHOULD KEEP MVFR CIGS AROUND FOR MUCH OF THE TAF PERIOD... ESPECIALLY ALONG THE COAST. NORTH WINDS AROUND 15 KTS WITH GUSTS OF 20-25 KTS ARE EXPECTED DURING THE DAY...BECOMING AOB 12 KTS AFTER 00Z THURSDAY AS THE GRADIENT RELAXES A BIT. EXTENDED OUTLOOK...SLIGHT CHANCE OF RAIN WITH MVFR CIGS POSSIBLE ON THURSDAY. VFR SHOULD PREVAIL FRIDAY THROUGH SUNDAY...ALTHOUGH MVFR/IFR CIGS COULD DEVELOP EARLY EACH MORNING. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...LOW PRESSURE LOCATED ABOUT 200 MILES EAST OF SAVANNAH HAS A CENTRAL PRESSURE OF ABOUT 1010 MB...NOT PARTICULARLY NOTEWORTHY. HOWEVER CANADIAN HIGH PRESSURE OVER NORTHERN NEW ENGLAND HAS A PRESSURE OF 1031 MB...AND THIS 21 MB OF PRESSURE GRADIENT IS PRODUCING STRONG NORTH WINDS ACROSS THE CAROLINA COASTAL WATERS. THE GALE WARNING FOR SUSTAINED WINDS AS HIGH AS 35 KNOTS WILL REMAIN IN EFFECT FOR THE SC WATERS THROUGH 8 AM...AND THROUGH 11 AM FOR THE NC WATERS. WINDS WILL NOT DIMINISH VERY QUICKLY HOWEVER...AND EVEN TONIGHT 20-25 KT WINDS WILL REQUIRE SMALL CRAFT ADVISORIES TO REMAIN POSTED. MODELS ARE IN SURPRISINGLY GOOD AGREEMENT WITH WIND SPEEDS AND DIRECTIONS THROUGH TONIGHT. SEAS CURRENTLY AS HIGH AS 10 FEET OUT AT THE FRYING PAN SHOALS BUOY ARE MEASURED AT 6 FEET AT THE NEARSHORE WRIGHTSVILLE BEACH BUOY AND AT THE NEW BUOY JUST SOUTH OF SOUTHPORT. SEAS HAVE GROWN ABOUT AS LARGE AS THE CURRENT WIND SPEED AND DIRECTION WILL ALLOW...AND WE SHOULD BEGIN TO NOTICE A DOWNWARD TREND IN SEA HEIGHTS LATER TODAY AS WINDS DIMINISH. RAINFALL IS MOST LIKELY THIS MORNING ACROSS THE WATERS NORTH OF CAPE FEAR...AND COULD VANISH FROM THE COASTAL WATERS ENTIRELY THIS AFTERNOON. LIGHT RAIN OR DRIZZLE COULD REDEVELOP THIS EVENING...ESPECIALLY ACROSS THE NC WATERS. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY...PINCHED SFC PG WILL CONTINUE ACROSS THE ILM WATERS THRUOUT THIS PERIOD. THIS A RESULT OF THE INTERACTION OF 1030MB HIGH RIDGING SSW ACROSS THE SPINE OF THE APPALACHIANS AND PERSISTENT LOW PRESSURE MEANDERING JUST OFFSHORE FROM THE CAROLINA COASTS. MODELS INDICATE A RATHER SLOW WEAKENING OR FILLING OF THIS SYSTEM THAT TRIES TO BECOME BAROTROPIC IN NATURE. THE SFC PRESSURE PATTERN ACROSS THE WATERS WILL YIELD A NORTHERLY WIND DIRECTION... NNW-NE. SPEEDS WILL PEAK DURING THE THURSDAY TIME FRAME AT OR SLIGHTLY BELOW SCA THRESHOLDS...FOLLOWED BY A SLOW DIMINISHING TREND THERE-AFTER INTO SATURDAY. SIGNIFICANT SEAS WILL ALSO FOLLOW SUIT AND PEAK AT THE BEGINNING OF THIS PERIOD...THURSDAY MORNING...AND SLOWLY SUBSIDE THERE-AFTER. AT TIMES...SWAN AND/OR WAVEWATCH3 WANT TO DECREASE SIGNIFICANT SEAS TOO QUICKLY GIVEN AN EVENT SIMILAR TO THIS. AS A RESULT...WILL STAY UP TO 1 FOOT HIER THAN SWAN/WW3 FOR SEAS DURING THIS PERIOD. DOMINATE PERIODS WILL RUN 7 TO 8 SECONDS. WILL LIKELY BE IN A TRANSITION FROM SCA CONDITIONS TO SCEC CONDITIONS DURING THIS TIME PERIOD. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY...THIS TIME PERIOD WILL AGAIN BE GOVERNED BY AN UPPER CLOSED LOW...RESULTING WITH A CONTINUED TIGHTENED SFC PG ACROSS THE ILM WATERS. THE TIGHTENED SFC PG EVOLVED FROM THE INTERACTION OF STRONG 1030+ MB HIGH PRESSURE CENTERED OVER NEW ENGLAND WHICH RIDGES SW ALONG THE SPINE OF THE APPALACHIANS...AND THE MEANDERING/DRIFTING UPPER CLOSED LOW AND ITS ASSOCIATED SFC LOW OFF THE COAST FROM THE OUTER BANKS. LOOKING AT NW-N WINDS ACROSS THE WATERS WITH SPEEDS IN THE 10-20 KT RANGE. SIG SEAS WILL HAVE DROPPED SOME TOWARDS THE END OF THE SHORT TERM...AND WILL LIKELY FOLLOW THIS TREND ESPECIALLY WHEN WINDS BECOME OFFSHORE. WAVEWATCH3 SEAS WERE UTILIZED FOR THIS PERIOD. ONCE AGAIN WILL BE FLIRTING WITH SCEC CRITERIA THRESHOLDS DURING THIS PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR AMZ254-256. GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR AMZ250-252. && $$ SYNOPSIS...DCH NEAR TERM...TRA SHORT TERM...DCH LONG TERM...DCH AVIATION...TRA/BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
130 AM EDT WED OCT 9 2013 .SYNOPSIS... A COMPLEX AREA OF LOW PRESSURE OFF THE SOUTHEAST COAST WILL MOVE SLOWLY NORTH UP THE MID-ATLANTIC COAST THROUGH LATE IN THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... AS OF 845 PM TUESDAY... TONIGHT... AND EARLY UPDATE TO THE FORECAST THIS EVENING TO LOWER POPS OVER THE NEXT FEW HOURS AS THE BAND OF MODERATE RAIN THAT COVERAGE THE CENTRAL CWA EARLIER TODAY AS SHIFTED SOUTH INTO SC. MOST OF THE RAIN IS NOW FOCUSED ALONG THE COAST WHERE BETTER LOW LEVEL FORCING AND WARM CONVEYOR BELT RESIDE. WATER VAPOR IMAGERY SUGGESTS THE CENTER OF THE DEVELOPING UPPER LOW AND ASSOCIATED NUMEROUS VORT MAXIMA IS OVER SC...AND THE LATEST RAP SHOWS THE MOST PROMINENT AND INVERTED 500MB TROUGH/VORT MAX EXTENDING FROM SC TO THE NORTHEAST TOWARD THE OBX. AN UPPER LEVEL JET STREAK ALSO APPEARS TO BE SURGING NORTHWARD ALONG THE CAROLINA COAST ON THE EASTERN SIDE OF THE DEVELOPING UPPER LOW. WHILE MODELS HAVE PERFORMED POORLY THUS FAR WITH THIS SYSTEM...THERE IS AT LEAST DECENT AGREEMENT AMONG THE 18Z GFS AND 12Z ECMWF AND THE LATEST RAP IN THE BEST UPPER FORCING FOCUSING FROM THE TRIANGLE TO THE EAST AND NORTHEAST...WHERE THE AFOREMENTIONED VORT MAX AND LEFT EXIT REGION OF THE JET SHOULD COINCIDE WITH INCREASING ONSHORE MOISTURE TRANSPORT. WILL INDICATE INCREASING POPS ACROSS THE EAST AND NORTHEAST AFTER MIDNIGHT...THOUGH WITHOUT GOOD SUPPORT FROM THE HI-RES MODELS... CONFIDENCE IS NOT HIGH ENOUGH FOR A LARGE AREA OF CATEGORICAL POPS AT THIS TIME. MAY REEVALUATE AFTER THE 00Z UPPER-AIR ANALYSIS. ELSEWHERE...WILL MAINTAIN AT LEAST A SLIGHT CHANCE TO CHANCE OF LIGHT RAIN OR DRIZZLE. LOWS SHOULDN`T MOVE MUCH LOWER THAN THEIR CURRENT VALUES UNDER OVERCAST SKIES...WITH LOWER 50S WEST AND UPPER 50S EAST. -SMITH WEDNESDAY/WEDNESDAY NIGHT... PERIODS OF RAIN MIXED WITH SPRINKLES SHOULD PERSIST THROUGHOUT MUCH OF THE DAY WEDNESDAY AND INTO WEDNESDAY NIGHT WITH HIGHER POPS GRADUALLY SHIFTING NORTHWARD WITH THE UPPER LOW. HIGHS IN THE LOW TO MID 60S. EXPECT A SHARP EAST TO WEST CUT-OFF IN RAINFALL AMOUNTS...RANGING FROM AS HIGH AS AN INCH IN EAST(AND WHERE EVER PRECIP BANDS SETUP) TO POSSIBLY ONLY TRACE AMOUNTS IN THE TRIAD. LOWS TOMORROW TONIGHT AGAIN IN THE LOWER TO MID 50S. -CBL && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 250 PM TUESDAY... UNCERTAINTY CONTINUES TO EXIST WITH THE EXACT DETAILS OF EVOLUTION OF A SLOW MOVING UPPER LEVEL LOW AND ASSOCIATED SURFACE LOW NEAR OR JUST OFFSHORE. THE LOW(S) WILL NOT MOVE VERY MUCH THROUGHOUT THE ENTIRE PERIOD AS A BLOCKING PATTERN PERSISTS ACROSS THE NORTHERN ATLANTIC. NEVERTHELESS...THE BIG QUESTION IS WHERE THESE LOWS WILL ULTIMATELY TRACK...AS ANY SHIFT IN THE TRACK WILL HAVE IMPACTS ON PRECIPITATION COVERAGE. AT THIS TIME IT APPEARS THE DEEP MOISTURE MAY GRADUALLY SHIFT OUT OF THE AREA FROM THE SOUTHWEST TO NORTHEAST DURING THIS TIME FRAME AS THE LOW(S) SHIFT SLIGHTLY TO THE NORTHEAST. THIS WOULD ALSO ALLOW THE PRECIP TO GRADUALLY COME TO AN END FROM SOUTHWEST TO NORTHEAST LATE THURSDAY INTO FRIDAY. HOWEVER...WILL KEEP SLIGHT CHANCE POPS IN ACROSS THE NORTHEAST PORTION OF THE FORECAST AREA THROUGHOUT THE ENTIRE PERIOD DUE TO THE CLOSER PROXIMITY OF THE LOW. CLOUDS SHOULD ALSO ACCORDINGLY THIN OUT SOME...BUT AM NOT EXPECTING COMPLETE CLEARING BY ANY MEANS... ESPECIALLY ACROSS THE NORTHEAST. HOWEVER...THIS SHOULD BE ENOUGH TO ALLOW TEMPS TO FINALLY RISE SOME...BUT WILL STILL BE BELOW NORMAL...GENERALLY MID/UPPER 60S ON THURSDAY AND UPPER 60S TO NEAR 70 DEGREES ON FRIDAY (COOLEST NORTHEAST/WARMEST SOUTHWEST). OVERNIGHT LOWS ARE EXPECTED TO BE IN THE LOW/MID 50S. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 250 PM TUESDAY... THE LINGERING UPPER LEVEL LOW AND PERSISTENT NORTHEASTERLY FLOW WILL RESULT IN CONTINUED CLOUDY AND RELATIVELY COOL CONDITIONS FOR THE FIRST PORTION OF THE PERIOD...WITH GRADUALLY IMPROVING CONDITIONS BY LATE IN THE WEEKEND OR EARLY NEXT WEEK. NEVERTHELESS...FOR THE WEEKEND...THE OVERALL PRECIP CHANCES SHOULD BE RELATIVELY LOWER THAN EARLIER IN THE WEEK. MODELS DO CONTINUE TO HINT AT THE UPPER LOW (WHICH IS PROGGED TO HAVE MOVED NORTH OF THE AREA BY THIS POINT) TO SHIFT BACK TO THE SOUTH AND EAST SATURDAY INTO SUNDAY...MOVING ACROSS THE NORTHEASTERN PORTION OF THE FORECAST AREA. THEREFORE... WILL MAINTAIN AT LEAST SLIGHT CHANCE POPS ACROSS THE NORTHEASTERN PORTIONS OF THE FORECAST AREA OVER THE WEEKEND...BEFORE RETURNING TO A DRY FORECAST BY EARLY NEXT WEEK AS WE FINALLY GET ON THE BACKSIDE OF THE LOW AS IT MOVES OFFSHORE AND HEIGHTS RISE ACROSS THE EAST COAST. TEMPS WILL ACCORDINGLY MODERATE THROUGH THE PERIOD WITH A RETURN TO SLIGHTLY ABOVE NORMAL TEMPS BY EARLY NEXT WEEK. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 130 AM WEDNESDAY... 24 HOUR TAF PERIOD: VERY LOW CONFIDENCE FORECAST THIS MORNING AS AN UPPER LEVEL LOW PRESSURE SYSTEM REMAINS STACKED OVER TOP OF A SURFACE LOW JUST OFF OF THE GEORGIA COAST. BANDED PRECIPITATION OVER THE CENTER OF THE CWA HAS WANED WITH MOST OF THE ACTIVITY CONFINED TO THE COASTAL PLAIN. CONTINUED LIGHT RAIN WILL PERSIST IN THE EAST OVERNIGHT AS THE LOW ROTATES THROUGH THE AREA. MVFR CEILINGS AT KFAY MAY SPREAD TO KRWI LATER THIS MORNING. FURTHER TO THE NORTHWEST... KRDU SHOULD REMAIN VFR BUT WILL BE RIGHT AROUND THE 3 KFT LEVEL AND MAY BOUNCE BETWEEN IFR/MVFR. THE TRIAD SITES ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. AFTER SUNRISE ON WEDNESDAY MVFR CEILINGS AND LIGHT RAIN MAY CONTINUE IN THE EAST AS SEVERAL IMPULSES ROTATE AROUND THE UPPER LOW. HEAVIER SHOWERS MAY BE EMBEDDED IN THE LIGHTER RAINFALL. LATE WEDNESDAY MORNING EXPECT GUSTS OUT OF THE NORTHEAST TO ONCE AGAIN PICK UP AND BY AFTERNOON 20-25 KT GUSTS CAN BE EXPECTED AT ALL TAF SITES. GUSTS ARE EXPECTED TO SLACK OFF A BIT NEAR THE END OF THE TAF PERIOD. LONG TERM: WEATHER HAS THE POTENTIAL TO REMAIN UNSETTLED FOR THE REST OF THE WEEK AS THE LOW PRESSURE SYSTEM MEANDERS NEARLY STATIONARY OFF THE COAST. KRWI IS THE MOST LIKELY SITE TO BE AFFECTED BY THIS SYSTEM THE LONGEST. EARLY NEXT WEEK A SMALL UPPER LEVEL RIDGE PUSHES THE LOW JUST FAR ENOUGH OUT TO SEA TO CLEAR THINGS UP A BIT ACROSS THE CAROLINAS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL/SMITH SHORT TERM...KRR LONG TERM...KRR AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 AM EDT WED OCT 9 2013 .SYNOPSIS... UNSETTLED WEATHER WILL PERSIST INTO WEDNESDAY WITH SOME GRADUAL IMPROVEMENT POSSIBLE ON THURSDAY AS LOW PRESSURE IS HESITANT TO MOVE AWAY FROM THE AREA. THE LATE WEEK AND WEEKEND WILL FEATURE A GRADUAL RETURN OF SEASONABLE WEATHER. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 130 AM WEDNESDAY...ASIDE FROM A SMALL AREA OF RAIN ACROSS WILLIAMSBURG COUNTY SC ASSOCIATED WITH THE UPPER LOW...ISENTROPIC LIFT CONTINUES TO PRODUCE WIDESPREAD LIGHT RAIN ACROSS FAR-EASTERN NORTH CAROLINA...EXTENDING AS FAR WEST AS WHITEVILLE AND ELIZABETHTOWN. RADAR PRESENTATION IS A LITTLE LESS THAN I HAD ANTICIPATED...SO QPF TOTALS HAVE BEEN CUT BETWEEN NOW AND DAYBREAK TO NO MORE THAN TWO-TENTHS OF AN INCH. LATEST HRRR MODEL SHOWS THERE SHOULD BE A SIGNIFICANT EROSION OF RAIN BY DAYBREAK. THE GFS SHARES THIS IDEA BUT THE 18Z/00Z NAM DISAGREE. GIVEN THE DISAGREEMENT I HAVE MADE LITTLE CHANGE EXCEPT FOR THE CURRENT RADAR INITIALIZATION. OUR LITTLE PORTION OF THE CAROLINAS IS THE CHILLIEST ANYWHERE IN THE EASTERN PIEDMONT OR COASTAL PLAIN OF THE CAROLINAS. NORTHERLY WINDS SHOULD ACTUALLY ADVECT NEUTRAL TO SLIGHTLY WARMER AIR IN FROM THE NORTH OVERNIGHT...AND WITHOUT SIGNIFICANT PRECIPITATION INLAND THERE SHOULD BE LITTLE ADDITIONAL EVAPORATIONAL COOLING. THIS MEANS WE ARE PROBABLY AT OUR ULTIMATE LOW TEMPERATURE NOW...WITH STEADY TEMPERATURES THROUGH DAYBREAK. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS... A BROAD AREA OF LOW PRESSURE WAS SITUATED ALONG A STALLED FRONT ABOUT 190 MILES SE OF WINYAH BAY LATE THIS EVE. HIGH PRESSURE POSITIONED TO OUR N WAS WEDGING SOUTHWARD ACROSS OUR INLAND MOST ZONES. AN UPPER LOW WAS CUTOFF FROM THE MAIN FLOW AND LOCATED ACROSS THE CAROLINAS. THE MODELS ARE INDICATING A VERY SLOW EVOLUTION OF THESE FEATURES. THE SURFACE LOW IS EXPECTED TO CREEP N OR CONSOLIDATE TO OUR N AND OFFSHORE OF CAPE HATTERAS...BUT IT MAY TAKE A GOOD 24 TO 36 HOURS FOR THIS TO OCCUR AS THE SYSTEM BECOMES VERTICALLY STACKED. MOST OF THE RAIN LATE THIS EVE IS CONFINED TO AREAS ALONG AND E OF A LINE FROM GALIVANTS FERRY TO WHITEVILLE AND UP THROUGH THE CAPE FEAR REGION. THE HIGH RESOLUTION MODELS CONTINUE TO SHOW THE HEAVIEST RAIN FALLING ACROSS THE ATLANTIC WATERS. HOWEVER...APPRECIABLE LIFT DOES BLEED ONTO THE COAST AND WILL SHOW THE HIGHEST POPS...UP TO CATEGORICAL...ALONG AND NEAR THE COAST WITH A VERY SLOW EROSION FROM S TO N THROUGH SUNRISE. COOL ADVECTION CONTINUES TO STRENGTHEN ON THE WEST SIDE OF THE OFFSHORE LOW AND OVERNIGHT LOWS HAVE BEEN LOWERED TO THE LOWER TO MID 50S WITH PERHAPS SOME UPPER 50S FOR PORTIONS OF THE IMMEDIATE COAST. THE PRESSURE GRADIENT BETWEEN THE TWO AFOREMENTIONED SYNOPTIC FEATURES WILL REMAIN TIGHT OVERNIGHT. THIS WILL KEEP WINDS IN THE 10 TO 20 MPH RANGE INLAND. ALONG THE COAST...WINDS WILL BE STRONGEST...15 TO 25 MPH WITH GUSTS IN EXCESS OF 30 MPH AT THE BEACHES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...1010MB LOW JUST OFF OF NE/EC FLORIDA COAST AND SHOWING LITTLE MOVEMENT. THIS WILL BE THE CASE THROUGH WEDNESDAY. MEANWHILE ANOTHER LOW WILL DEVELOP ALONG THE ORIGINALS WARM FRONT EAST OF HSE AND RETROGRADE INTO THE OBX BY WEDNESDAY NIGHT. THE INTERACTION BETWEEN THE TWO WILL DICTATE HOW MUCH ADDITIONAL RAINFALL THE AREA SEES. FOR NOW IT STILL SEEMS LIKE GOOD RAINFALL CHANCES...HIGHEST ALONG THE COAST...BUT THE OPPORTUNITY FOR HEAVY RAINFALL SEEMS TO BE RAPIDLY ON THE WANE AS THE STRONGEST MOISTURE FLUX SHIFTS TO OUR NORTH BY AFTERNOON/EVENING. TEMPERATURE GUIDANCE PROBABLY OUT OF WHACK AND NOT RESPECTING SHALLOW (1500FT) COOL AIR AS INDICATED BY LARGE ERRORS IN THE CURRENT SITUATION/TUE AFTERNOON. IN FACT BASED ON FCST SOUNDINGS SHOULD EVEN LIGHT RAIN KEEP FALLING INTO THIS WEDGE ANOTHER DAY OF NEAR 60 MAY BE ON TAP...A BIT COOLER THAN CURRENT FCST OF MID 60S BUT SOME 10 DEGREES COOLER THAN MOST GUIDANCE. THURSDAY IS A TOUGH FORECAST TOO. GFS HAS THE NORTHERN LOW BECOME DOMINANT AND WEAKENS THE SOUTHERN/FLORIDA LOW TO JUST AN OPEN TROUGH. THE WRF HAS BOTH MAINTAIN AS SEPARATE YET SEEMINGLY WANTING TO CONGEAL LOW CENTERS. THE WRF WOULD PROBABLY IMPLY A BETTER CHANCE OF YET ANOTHER GRAY AND COLD DAY WHERE THE GFS SHOWS WRAP-AROUND MOISTURE OVER NRN ZONES BUT POSSIBLY SOME BREAKS SOUTH AND WEST. SUSPECT THAT THE WRF SOLN IS SLIGHTLY MORE REALISTIC AS THE SOUTHERN SURFACE LOW REMAINS CLOSE TO THE UPPER WAVE AND SHOULD NOT FILL AS QUICKLY AS PROGGED BY GFS EVEN DESPITE ITS OCCLUSION AS GULF STREAM SHOULD PROVIDE SOME BAROCLINICITY. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...SFC HIGH PRESSURE WILL CONTINUE TO EXTEND DOWN THE APPALACHIANS WHILE COASTAL TROUGH/LOW EXTENDS UP THE EASTERN SEA BOARD SHIFTING SLOWLY EAST THROUGH THE WEEKEND INTO EARLY NEXT WEEK. IN THE MID TO HIGH LEVELS...A CUTOFF LOW OVER THE VA/NC BORDER ON FRIDAY WILL ALSO DRIFT SLOWLY EAST THROUGH THE PERIOD AS RIDGE OF HIGH PRESSURE EXTENDS UP FROM THE GOM TO THE GREAT LAKES MOVING SLOWLY EAST AS WELL. THE MODELS ALL SHOW THIS TO VARYING EXTENTS IN BOTH INTENSITY AND MOVEMENT. WITH THE LOW TO OUR NORTH AND EAST WE SHOULD EXPERIENCE SOME SUBSIDENCE AND DRYING THROUGH THE MID LEVELS BUT THE BIG QUESTION IS HOW MUCH WILL THE LOW LEVELS DRY OUT TO SCOUR OUT THE CLOUDS AND MOISTURE. MODEL SOUNDINGS AND MOISTURE PROFILES DO SHOW SOME DRYING THROUGH THE LOW TO MID LEVELS ACROSS INLAND PORTIONS OF FORECAST AREA BUT HOLD ONTO CLOUD DECK NEAR THE COAST...MAINLY NORTH OF CAPE FEAR. OVERALL WILL MAINTAIN A MORE OPTIMISTIC FORECAST WITH DEEP NORTHERLY FLOW THROUGH MUCH OF THE PERIOD WITH INCREASED SUBSIDENCE AND DRY AIR AND SUN BREAKING OUT. IF LOW PRESSURE DRIFTS MORE SOUTHWARD BEFORE MOVING FURTHER OFF SHORE...THERE WILL BE A GREATER CHC OF CLOUDS BUT ANY APPRECIABLE PCP WILL BE KEPT OUT OF FORECAST REMAINING FURTHER NORTH AND EAST. THEREFORE GRADIENT SHOULD RUN FROM NORTHEAST TO SOUTHWEST WITH BEST CHC OF SUNSHINE AND WARMER TEMPS BEING OVER SOUTHWEST PORTIONS OF CWA...OVER INLAND SOUTH CAROLINA. THE MID TO UPPER RIDGE PUSHING IN FROM THE WEST WILL BRING A SLOW RISE IN HEIGHTS ESPECIALLY ACROSS INLAND AREAS BUT A COOL NORTHERLY FLOW WILL PERSIST THROUGH THE PERIOD ON THE FRONT END OF SFC HIGH PRESSURE WEDGED IN ACROSS THE INLAND CAROLINAS FROM NEW ENGLAND. THE GFS IS THE MOST AGGRESSIVE IN TERMS OF DEPTH AND SOUTHERN EXTENT OF UPPER LOW OVER THE WEEKEND KEEPING A MORE PESSIMISTIC AND COOLER FORECAST...ESPECIALLY OVER NORTH CAROLINA COAST. AGAIN...WILL KEEP WITH GREATER AMOUNT OF SUNSHINE AND WARMER TEMPS THE FARTHER SOUTHWEST YOU GO. BASICALLY SOME UNCERTAINTY REMAINS AS THE MODELS NEED TO RESOLVE THE STRENGTH AND SOUTHERN EXTENT OF LOW WHICH IN TURN COULD POSSIBLY CREATING A TIGHTENED GRADIENT WITH GREATER NORTHERLY WINDS AT TIMES PRODUCING A REINFORCEMENT OF COOLER AIR OR GREATER MOISTURE. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...EXPECT PERIODS OF RAIN OVERNIGHT...MAINLY ALONG THE COAST...ALONG WITH MVFR/IFR CIGS. HIGHEST CONFIDENCE FOR IFR IS AT KILM WHERE CIGS BELOW 1KFT HAVE BEEN MOST PERSISTENT. MVFR CIGS SHOULD PREVAIL AT CRE/MYR/FLO/LBT. THE BEST-INITIALIZED MODEL APPEARS TO BE THE 04Z RUC WHICH CAPTURES SURFACE TEMPERATURE/ DEWPOINT TRENDS AND CEILING HEIGHTS THE BEST. THE SFC LOW OFFSHORE WILL GRADUALLY MOVE UP THE ATLANTIC COAST TODAY...AND WITH IT THE BEST LIFT WILL BE DISPLACED TO OUR NORTH. WILL KEEP A MENTION OF VCSH IN THE FCST...BUT IT APPEARS PCPN CHANCES DIMINISH FOR MUCH OF OUR AREA BY THE AFTN. THE LOW-LEVEL INVERSION SHOULD KEEP MVFR CIGS AROUND FOR MUCH OF THE TAF PERIOD... ESPECIALLY ALONG THE COAST. NORTH WINDS AROUND 15 KTS WITH GUSTS OF 20-25 KTS ARE EXPECTED DURING THE DAY...BECOMING AOB 12 KTS AFTER 00Z THURSDAY AS THE GRADIENT RELAXES A BIT. EXTENDED OUTLOOK...SLIGHT CHANCE OF RAIN WITH MVFR CIGS POSSIBLE ON THURSDAY. VFR SHOULD PREVAIL FRIDAY THROUGH SUNDAY...ALTHOUGH MVFR/IFR CIGS COULD DEVELOP EARLY EACH MORNING. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM WEDNESDAY...GUSTS IN THE PAST TWO HOURS HAVE BEEN AS HIGH AS 39 KNOTS OUT AT THE FRYING PAN SHOALS BUOY OFFSHORE. WITHIN 20 MILES OF SHORE MEASURED WIND GUSTS HAVE BEEN LOWER...BUT THE POTENTIAL FOR GALE CONDITIONS REMAINS PRESENT. NO SIGNIFICANT CHANGES ARE NEEDED. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS... A GALE WARNING HAS BEEN RAISED. LOW PRESSURE WAS CREEPING UP ALONG A FRONTAL BOUNDARY STALLED OFF THE CAROLINA COAST. AT THE SAME TIME...HIGH PRESSURE WAS WEDGING INTO THE CAROLINAS FROM THE N. THE DIFFERENCE IN PRESSURE BETWEEN THESE TWO SYSTEMS WAS PRODUCING A VERY TIGHT GRADIENT ACROSS THE WATERS. THE RESULT WAS SUSTAINED OR FREQUENT GUSTS TO GALE FORCE. THE PRESSURE GRADIENT IS EXPECTED TO ONLY SLOWLY RELAX AND THIS MAY ALLOW WINDS TO DIMINISH SLIGHTLY DURING WED. THE WINDS WILL BE FROM THE NNE. THE STRONG WINDS HAVE BUILT SEAS UP TO 7 TO 10 FT AND LITTLE CHANGE IS EXPECTED OVERNIGHT. SEAS WILL BE LOWER IN THE SHADOW OF BRUNSWICK COUNTY. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...LOW PRESSURE EAST OF NRN FLORIDA COAST TO WOBBLE AROUND NEARLY STATIONARY MOST OF WEDNESDAY. SECONDARY LOW FORMS ALONG WARM FRONTAL BOUNDARY WELL OFFSHORE AND RETROGRADES TOWARDS OBX LATE WED NIGHT. THE INTERACTION BETWEEN THE TWO WILL AFFECT THE EVENTUAL WEAKENING OF THE WIND AND WAVES LOCALLY. THERE IS JUST ENOUGH MODEL SPREAD TO MAKE IT UNCLEAR AS TO THE SPEED WITH WHICH THIS OCCURS AND HOW VALID OUR END TIMES ARE FOR THE CURRENT ADVISORY. CURRENT UPDATE SUGGEST THAT NRN ZONES MAY BE FINE BUT AREAS FURTHER SOUTH MAY BE ABLE TO BE LOWERED TO SCEC OR CANCELLED ALTOGETHER. SIMILARLY...THE UNCERTAINTY SUGGEST THAT MAKING CHANGES AT THIS TIME OF LITTLE VALUE IN CASE THINGS CHANGE. LATER THURSDAY AS THE SOUTHERN LOW WEAKENS AND THE NORTHERN ONE MOVES FURTHER NORTH THE LOCAL FLOW WILL BACK IN DIRECTION AND EASE SLIGHTLY IN SPEED. OR THE TWO MAY TAKE ON A MORE CONGEALED FORM WITH TWO WEAK CENTERS VYING TO REMAIN...WHICH AT THIS POINT IS SEEMINGLY A LITTLE MORE PLAUSIBLE. EITHER WAY NO FLAGS OR HEADLINES EXPECTED THURSDAY. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 PM TUESDAY...SFC HIGH PRESSURE WILL CONTINUE TO EXTEND DOWN THE APPALACHIANS WHILE COASTAL TROUGH/LOW EXTENDS UP THE EASTERN SEA BOARD SHIFTING SLOWLY EAST INTO THE ATLANTIC WATERS THROUGH THE WEEKEND. OVERALL EXPECT NORTHERLY WINDS TO CONTINUE IN A PINCHED GRADIENT FLOW BETWEEN THE TWO SYSTEMS. WINDS SHOULD BE 10-15 KTS THROUGH MOST OF THE WEEKEND BUT THE STRENGTH MAY VARY DEPENDING ON HOW FAR SOUTH AND EAST THE LOW TRACKS BEFORE IT MOVES AWAY WILL DETERMINE THE STRENGTH OF THE WINDS. ALSO...THE COOL AIR RIDING OVER THE WARMER WATERS WILL KEEP STRONGER AND GUSTIER WINDS...ESPECIALLY AT NIGHT. SEAS SHOULD REMAIN 2-4 FT THROUGH THE PERIOD WITH A NORTHERLY WIND WAVE WHICH MAY KICK UP THE SEAS AT TIMES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...GALE WARNING UNTIL 8 AM EDT WEDNESDAY FOR AMZ250-252- 254-256. && $$ NEAR TERM...RJD/TRA SHORT TERM...MBB LONG TERM...RGZ AVIATION...BJR/TRA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
225 AM CDT WED OCT 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM CDT WED OCT 9 2013 MAIN SHORT TERM FORECAST CONCERNS ARE ON WINDS AND TEMPERATURES TODAY. CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEPENING TROUGHING OVER THE WESTERN U.S. AND STRENGTHENING RIDGING FROM LOUISIANA INTO THE GREAT LAKES. THE SOUTHWEST FLOW BETWEEN THESE FEATURES HAS BEEN BRINGING A VARIETY OF WEAK SHORTWAVES TOWARDS THE FORECAST AREA. HOWEVER...DUE TO PLENTIFUL DRY AIR IN THE LOW TO MID LEVELS OF THE TROPOSPHERE AS EVIDENCED ON 00Z SOUNDINGS FROM DDC TO OAX AND MPX...THE SHORTWAVES HAVE BEEN ONLY ABLE TO PRODUCE SCT-BKN CIRRUS CLOUDS. OF SOMEWHAT MORE SIGNIFICANCE IS THE STRENGTH OF THE LOW LEVEL SOUTHWEST FLOW. AHEAD OF A COLD FRONT DRAPED FROM NORTHWEST MN INTO WESTERN NEBRASKA PER SURFACE ANALYSIS...35-50 KT SOUTHWEST 850MB WINDS WERE PRESENT FROM WESTERN KANSAS THROUGH THE FORECAST AREA AND INTO UPPER MICHIGAN. SOME OF THIS BREEZE EXTENDS DOWN THE SURFACE...HELPING TO KEEP TEMPERATURES WELL ABOVE NORMAL DESPITE SURFACE DEWPOINTS IN THE MID 40S. OVER THE NEXT 24 HOURS...MODELS ARE IN GOOD AGREEMENT OF THE WESTERN TROUGH DIGGING DEEPER...FEATURING AN UPPER LOW IN THE VICINITY OF LAS VEGAS BY 12Z THURSDAY. MEANWHILE...THE UPPER RIDGE DOWNSTREAM STRENGTHENS FURTHER TO HELP BALANCE THE DEEPER WESTERN TROUGH... RESULTING IN A BLOCKED UP PATTERN. THUS...THAT FRONTAL BOUNDARY FROM NORTHWEST MN INTO WESTERN NEBRASKA GOES NOWHERE AND THE FORECAST AREA STAYS IN DRY LOW TO MID LEVEL SOUTHWEST FLOW. THE PRESSURE GRADIENT MAGNITUDE...A MEASURE OF HOW TIGHT THE PRESSURE GRADIENT IS...MODELS PROG TO BE 40-50 PERCENT LESS THAN YESTERDAY. SO ALTHOUGH MIXING AND MAINTAINING A DECENT PRESSURE GRADIENT STILL SUGGESTS BREEZY CONDITIONS...ESPECIALLY WEST OF THE MISSISSIPPI RIVER...EXPECT WINDS TO NOT BE AS GUSTY AS YESTERDAY. 925MB TEMPERATURES TODAY ARE FORECAST ABOUT 2C COOLER COMPARED TO YESTERDAY...RANGING FROM 14-16C VERSUS THE 17-20C OBSERVED FROM 00Z SOUNDINGS. IT APPEARS THE REASON FOR THE COOLER CONDITIONS IS THE LOW LEVEL FLOW BACKING MORE SOUTHERLY. THEREFORE...HIGHS ARE LIKELY TO BE A FEW DEGREES COOLER. A SOUTHERLY BREEZE LOOKS TO PERSIST TONIGHT...BUT NOT AS STRONG AS THIS MORNING. THIS MEANS THE TYPICAL COLD SPOTS IN WISCONSIN STAND A MUCH BETTER CHANCE OF DECOUPLING AND DROPPING CLOSER TO THE DRIER DEWPOINTS IN PLACE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 225 AM CDT WED OCT 9 2013 MAIN LONG TERM FORECAST CONCERNS ARE ON WINDS FRIDAY AND POTENTIAL FOR PRECIPITATION FRIDAY THROUGH SATURDAY. SYNOPTIC OVERVIEW... MUCH OF THE FOCUS ON THE FORECAST REMAINS ON THE EVOLUTION OF THE WESTERN TROUGH...AND IN PARTICULAR THE UPPER LOW NEAR LAS VEGAS AT 12Z THURSDAY. GOOD MODEL AGREEMENT EXISTS THAT THE UPPER LOW WILL GET EJECTED OUT AND SHUNTED NORTH THROUGH THE DAKOTAS ON FRIDAY. FROM THERE INDICATIONS ARE THAT PHASING OCCURS WITH A SHORTWAVE TROUGH COMING THROUGH THE NORTHERN STREAM ACROSS SOUTH CENTRAL CANADA...RESULTING IN A FAIRLY DEEP LOW PRESSURE SYSTEM IN MANITOBA COME SATURDAY. THIS SYSTEM LIFTS OUT ON SUNDAY WHILE NEW TROUGHING RELOADS OVER THE WESTERN U.S.. THERE ARE PLENTY OF DISAGREEMENTS AMONGST THE MODEL HANDLING OF THIS NEW WESTERN TROUGH...PRIMARILY ITS PROGRESSION EAST WHERE THE 09.00Z GFS IS MUCH FASTER THAN THE 09.00Z CANADIAN/ECMWF AND 09.00Z CANADIAN ENSEMBLES. DETAILS... THURSDAY AND THURSDAY NIGHT WILL REMAIN DRY WITH THE BLOCKED UP PATTERN AHEAD OF THE WESTERN TROUGH. WINDS LOOK TO GRADUALLY INCREASE OUT OF THE SOUTH/SOUTHEAST AS WELL...IN RESPONSE TO DYNAMICAL FORCING DOWNSTREAM OF THE UPPER LOW EJECTING OUT CAUSING PRESSURES TO LOWER OVER THE PLAINS. 925MB TEMPS CLIMB ABOUT 1C FROM TODAY...RESULTING IN A SLIGHTLY WARMER DAY. MORE WIND AT NIGHT...ESPECIALLY ABOVE THE SURFACE...SHOULD HELP TO PRODUCE A WARMER NIGHT AS WELL. FRIDAY REMAINS A DAY TO FOCUS ON WINDS. AS THE UPPER AND SURFACE LOWS LIFT THROUGH THE DAKOTAS ON FRIDAY...THE PRESSURE GRADIENT TIGHTENS FURTHER OVER THE FORECAST AREA. THE MAGNITUDE OF THE GRADIENT IS ON PAR WITH THAT SEEN YESTERDAY...EXCEPT ALL OF THE FORECAST AREA SEES THE STRONGER GRADIENT VERSUS JUST WEST OF THE MISSISSIPPI RIVER. THUS A WINDY DAY IS LIKELY EVERYWHERE... ESPECIALLY IN HIGHER TERRAIN EXPOSED LOCATIONS. MIXING ON FORECAST SOUNDINGS FROM THE 09.00Z GFS/NAM SUGGEST WIND ADVISORY CRITERIA COULD BE REACHED IN THOSE LOCATIONS...SUCH AS DODGE CENTER AND ROCHESTER MN. THE WINDS ALSO HELP DRIVE UP 925MB TEMPS TO 16-18C...SUPPORTING HIGHS AS MUCH AS THE MID TO UPPER 70S DEPENDING ON AMOUNT OF SUNSHINE. LATE FRIDAY THROUGH SATURDAY FOCUS SWITCHES TO PRECIPITATION POTENTIAL. SOUTHERLY FLOW AHEAD OF THE UPPER AND SURFACE LOWS HEADING UP INTO MANITOBA HELPS TO DRAW HIGHER PRECIPITABLE WATER VALUES INTO THE FORECAST AREA. VALUES ARE PROGGED TO REACH 1-1.2 INCHES BY 00Z SATURDAY VERSUS THE 0.3-0.6 INCHES PRIOR TO THEN. THOSE VALUES ARE ACTUALLY 150-200 PERCENT OF NORMAL. THE QUESTION IS IF FORCING EXISTS TO ACT ON THE MOISTURE TO SQUEEZE OUT SOME RAIN. THE TRACK OF THE UPPER LOW IS UNDESIRABLE...KEEPING THE DPVA FORCING FROM IT NORTHWEST OF THE AREA. A SMALL PORTION OF THE WARM CONVEYOR BELT AHEAD OF THE UPPER LOW MAY BRUSH WESTERN PORTIONS OF THE FORECAST AREA LATE FRIDAY WITH SOME LIGHT RAIN SHOWERS OR SPRINKLES...BUT THIS IS A LOW CHANCE. FRIDAY NIGHT MAY STAND TO HAVE THE GREATEST CHANCE OF RAIN...IF THE 09.00Z CANADIAN MODEL FORECAST IS CORRECT. THE MODEL BRINGS UP A STRONGER SHORTWAVE THAN INDICATED BY ALL OTHER MODELS THROUGH THE SOUTHWEST FLOW INTO IOWA BY 12Z SATURDAY. THIS SHORTWAVE HELPS TIGHTEN UP THE FRONTOGENESIS AROUND A COLD FRONTAL BOUNDARY MAKING ITS WAY THROUGH THE FORECAST AREA... LEADING TO A BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS. MEANWHILE...THE 09.00Z GFS/NAM POINT TO A DRY OR MOSTLY DRY SCENARIO. FOR NOW HAVE MAINTAINED 20 PERCENT CHANCES OF SHOWERS AND THUNDERSTORMS BUT WOULD NOT BE SURPRISED TO HAVE TO CHANGE TO A DRY FORECAST. SATURDAY IS STILL UP IN THE AIR...WITH THE 09.00Z GFS/CANADIAN AND 08.12Z ECMWF TRENDING DRIER...SUGGESTING ANY ADDITIONAL FRONTOGENETIC OR INSTABILITY FORCING ALONG THE COLD FRONT OCCURS MOSTLY EAST OF THE FORECAST AREA. HOWEVER...THE 09.00Z ECMWF CAME BACK SHOWING THIS FORCING OCCURRING FARTHER WEST...ENCOMPASSING THE SOUTHEAST HALF OF THE AREA IN PRECIPITATION. THUS CHANCES OF PRECIPITATION NEED TO REMAIN IN THE FORECAST FOR SATURDAY. LOOKING FARTHER AHEAD...THE ONLY FEATURE OF NOTE WILL BE A LOW PRESSURE SYSTEM THAT DEVELOPS OVER THE PLAINS SUNDAY INTO MONDAY... ASSOCIATED WITH THE NEW WESTERN TROUGH. MUCH UNCERTAINTY EXISTS ON WHEN THE SYSTEM EVENTUALLY IMPACTS THE REGION...THEREFORE...HAVE FOLLOWED A MODEL CONSENSUS FOR TEMPERATURES AND PRECIPITATION CHANCES. IT DOES APPEAR RIGHT NOW THAT THE FORECAST AREA WILL LIE ON THE NORTH/COOL SIDE OF THE SYSTEM...WHICH WOULD SUGGEST A GREATER CHANCE OF SEEING RAIN. FOR WHAT ITS WORTH...THE 09.00Z GFS REALLY DEEPENS THE SYSTEM ENOUGH TO ALLOW FOR A RAIN/SNOW MIX...BUT THIS SOLUTION IS VERY HARD TO TRUST GIVEN THE MODEL UNCERTAINTY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1143 PM CDT TUE OCT 8 2013 THE MAIN CONCERN AT THE TAF SITES IS WITH LOW LEVEL WIND SHEAR TONIGHT AS THE SURFACE WINDS HAVE DECOUPLED TO AROUND 10-12KTS. LOCAL WIND PROFILERS SUGGEST THAT LOW LEVEL WINDS ARE IN THE 40-50KT RANGE WHILE SHORT TERM GUIDANCE SUGGESTING THAT IT WILL LAST THROUGH THE EARLY MORNING HOURS. GUSTY WINDS ARE EXPECTED AGAIN ON WEDNESDAY AT RST WITH PEAK GUSTS AROUND 22KTS OR SO. OTHERWISE...EXPECT VFR CONDITIONS THROUGHOUT WITH JUST HIGH LEVEL CLOUDS AROUND. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1022 PM MDT TUE OCT 8 2013 .SHORT TERM...(TONIGHT THROUGH THURSDAY) ISSUED AT 300 PM MDT TUE OCT 8 2013 THE MID AND HIGH CLOUDS WILL CONTINUE TO SLOWLY DECREASE OVER THE EAST PART OF THE CWA TONIGHT AS THE FLOW ALOFT BACKS. MEANWHILE... SOME OF THE UPSTREAM CLOUDS SHOULD SPREAD OVER THE WEST PART OF THE CWA. SOUTHWEST WINDS WILL GUST AS 40 MPH THROUGH SUNSET IN AREAS ALONG AND WEST OF THE LARAMIE RANGE. A SHALLOW COLD FRONT CURRENTLY OVER THE FAR NORTH PART OF THE CWA WILL MOVE MORE RAPIDLY SOUTH AND ACROSS THE CWA TONIGHT. WINDS BEHIND THE FRONT TURN TO THE NORTHEAST AND THE BOUNDARY LAYER WILL MOISTEN...WHICH SHOULD ALLOW FOR LOWER CLOUDS TO FORM OVER MAINLY THE NORTH HALF OF THE CWA AFTER 06Z AND PERSIST THROUGH 16Z WEDNESDAY. THE REST OF THIS PORTION OF THE FORECAST WILL BE DOMINATED BY THE STORM SYSTEM OVER THE PACIFIC NORTHWEST EARLY THIS AFTERNOON. THE STORM WAS STARTING TO DEVELOP A MID LEVEL CIRCULATION AND WAS DIGGING QUICKLY SOUTH. THAT DIGGING CONTINUES THROUGH EARLY WEDNESDAY NIGHT WITH THE CLOSED LOW OVER SOUTHERN CALIFORNIA AT 06Z THURSDAY. THE STORM IS TEN EJECTED TO THE NORTHEAST AS THE 300 MB JET ROUNDS THE BASE OF THE LOW. BY 00Z FRIDAY...THE FEATURE WILL START TO FILL AND BE OVER WESTERN COLORADO. UPPER LEVEL DIFFLUENCE AHEAD OF THE STORM WILL SPREAD CLOUDS AND SHOWERS OVER THE CWA THURSDAY AND THURSDAY NIGHT. THE 12Z MODEL TRENDS HAVE BEEN FOR A SLOWER NORTHEAST MOVEMENT OF THE STORM. AT THE SURFACE A BROAD LOW WILL BE PRESENT WEDNESDAY NIGHT...CENTERED OVER UTAH. THE LOW WILL THEN DEEPEN QUICKLY AND BE LOCATED OVER NORTHEAST COLORADO BY 00Z FRIDAY. THIS STORM TRACK IS SIMILAR TO THE STORM OF LAST WEEK...BUT THE AIR MASS ORIGIN IS MORE MARITIME AND WILL KEEP SNOW LEVELS HIGHER. TEMPERATURES WILL BE COOLER AND CLOSER TO NORMAL FOR WEDNESDAY AND THURSDAY OVER THE CWA. SOME SHOWERS WILL BE OVER AND WEST OF THE LARAMIE RANGE WEDNESDAY AFTERNOON. THEN AS THE STORM MOVES EAST...SHOWERS WILL LIKEWISE SPREAD EAST. ONE TO THREE INCHES OF SNOW WILL BE POSSIBLE ABOVE 9000 FEET THURSDAY AND THURSDAY NIGHT...WITH SNOW LEVEL AT 7500 TO 8000 FEET. THUNDERSTORMS WILL BE POSSIBLE OVER THE PANHANDLE THURSDAY AFTERNOON AS MOISTURE AND DYNAMICS INCREASE. THE BEST AXIS OF INSTABILITY LOOKS TO BE JUST EAST OF THE CWA AT THAT TIME. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 300 PM MDT TUE OCT 8 2013 THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THURS NIGHT AND FRI SHOWING THE UPPER LEVEL TROUGH QUICKLY SWINGING NORTHEAST ACROSS THE CWA. CYCLOGENESIS OCCURS ACROSS NORTHERN NEBRASKA BY 12Z FRI WITH THE PRESSURE GRADIENT INCREASING OVER THE REGION...ESPECIALLY ALONG AND EAST OF THE LARAMIE RANGE. THINKING THAT ADVISORY LEVEL WINDS WILL BE A CONCERN ACROSS THE PANHANDLE BY LATE THURS NIGHT WITH NORTHWESTERLY 850MB WINDS AT 30 KTS. WOULD ALSO WATCH THE SOUTHERN LARAMIE RANGE BETWEEN 06-15Z FRI AS THE GFS SHOWS 700MB WEST WINDS AT 55 KTS. IT IS NOT EXPECTED TO BE AN EXTENDED STRONG WIND EVENT SINCE THE UPPER TROUGH IS MOVING SO QUICKLY WITH THE PRESSURE GRADIENT DECREASING BY EARLY FRI AFTN. BEST CHANCE OF PRECIP ON THURS NIGHT WILL BE OVER THE NEBRASKA PANHANDLE ON THE BACKSIDE OF THE UPPER LOW...AND THIS WILL FALL AS RAIN WITH 850MB TEMPS AROUND 8C. WEAK SHORTWAVE MOVES OVER THE SOUTHERN PART OF THE CWA ON FRI NIGHT MAINTAINING THE CYCLONIC FLOW ALOFT. THE ECMWF IS STRONGER WITH THE WAVE AND PRODUCES MORE WIDESPREAD PRECIP...MAINLY ACROSS THE NORTHERN COLORADO. THINK THAT THIS MAY BE A BIT OVERDONE BUT DID KEEP SLIGHT CHANCE POPS IN THE FCST. THE WEEKEND WILL FEATURE SEASONAL TEMPS WITH WEAK WINDS AS A WEAK TROUGH IS ANCHORED OVER THE INTERMOUNTAIN WEST. BOTH THE GFS AND ECMWF INDICATE THE TROUGH AMPLIFYING TO THE WEST OF THE CWA BY SUNDAY INTO MONDAY. THIS WOULD RESULT IN COLDER TEMPS AND A BETTER CHANCE OF PRECIP BY LATE SUNDAY INTO EARLY NEXT WEEK BEHIND THE FROPA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING) ISSUED AT 1017 PM MDT TUE OCT 8 2013 CONFIDENCE LOWERING NOW ON IFR CHANCES IN THE PANHANDLE TONIGHT. FIRST...11-3.9U SATALLITE IMAGERY SHOWING NO SIGNS OF LOW CLOUDS DEVELOPING AS OF 04Z. LATEST SREF AND HRRR FORECASTS ALSO DO NOT SHOW THIS STRATUS DEVELOPING EITHER...SO DECIDED TO PULL THE LOW CEILINGS OUT OF THE PANHANDLE TAFS FOR 06Z. SHOULD START SEEING AN INCREASE IN CLOUDS WEDNESDAY AFTERNOON WITH SOME CONVECTION DEVELOPING MAINLY OVER THE MOUNTAINS TO OUR WEST. CHANCES IMPROVE FOR LOW CEILINGS WEDNESDAY NIGHT AS NORTHEAST UPSLOPING WINDS AND BETTER LOW LEVEL MOISTURE MOVE INTO THE AREA. && .FIRE WEATHER... ISSUED AT 300 PM MDT TUE OCT 8 2013 FIRE WEATHER CONCERNS WILL BE MINIMAL THROUGH EARLY NEXT WEEK OVER THE CWA. THE MILD AND DRY CONDITIONS CURRENTLY OVER THE CWA WILL CHANGE TO COOLER AND MORE NORMAL TEMPERATURES STARTING WEDNESDAY. THE SOUTHWEST SURFACE WINDS WILL GUST AS HIGH AS 40 MPH ALONG AND WEST OF THE LARAMIE RANGE THROUGH SUNSET. A COLD FRONT WILL MOVE ACROSS THE CWA FROM THE NORTH TONIGHT AND WILL USHER IN THE COOLER TEMPERATURES AND A NORTHEAST WIND. A PACIFIC STORM SYSTEM WILL MOVE ACROSS THE REGION THURSDAY THROUGH FRIDAY. THE STORM WILL BRING WIDESPREAD SHOWERS TO THE CWA DURING THAT TIME. THE SNOW LEVEL WILL BE AROUND 7500 FEET WITH THIS STORM...SO EVEN THOUGH THE EXPECTED PATH IS SIMILAR TO THE STORM OF LAST WEEK...IT IS WARMER AND SO RAIN SHOULD BE MORE COMMON IN MOST AREAS. WEST TO NORTHWEST WINDS INCREASE OVER THE AREA THURSDAY NIGHT AND FRIDAY AS THE STORM MOVES EAST OF THE CWA. ANOTHER STORM SYSTEM WILL AFFECT THE REGION EARLY NEXT WEEK AND WILL PRODUCE ANOTHER CHANCE OF RAIN AND SNOW. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...WEILAND LONG TERM...FINCH AVIATION...CLAYCOMB FIRE WEATHER...WEILAND Area Forecast Discussion National Weather Service Lincoln IL 950 AM CDT Wed Oct 9 2013 .DISCUSSION... ISSUED 950 AM CDT Wed Oct 9 2013 Illinois remaining on the periphery of the high pressure that was centered in New England this morning. Latest satellite imagery showing some stratocumulus spreading northward through southern Illinois. Latest RAP model humidity plot for 925-850 mb shows some of this creeping up to around I-64 this afternoon, but mainly sunny skies will prevail over the CWA. Have sent some updated grids to refresh the hourly temperature and dew point trends, but no changes needed to the zones at this time. Geelhart && .AVIATION... ISSUED 602 AM CDT Wed Oct 9 2013 VFR conditions will continue next 24hrs at all TAF sites. High pressure will continue to hold to our east through the period bringing a mostly clear sky and a light southeast wind. Model forecast soundings and time height cross sections continue to indicate moisture in the 3000-4000 foot level to our southeast will gradually edge north and northwest into our southern TAF areas late tomorrow night. Current indications suggest most if not all the clouds should remain south of our area thru 06z Thursday, but then advance northward enough to affect some of the sites between 09 and 12z. Surface winds will be out of a southeasterly direction at 10 kts or less. Auten && .PREV DISCUSSION... ISSUED 238 AM CDT Wed Oct 9 2013 SHORT TERM...Today through Friday Sprawling high pressure extending from New England to the Southern Plains will dominate the weather across central Illinois over the next couple of days. With ridge axis overhead today, light E/SE winds and slightly lower mixing heights will result in high temps a degree or two cooler than yesterday...with readings generally topping out in the lower to middle 70s. Once the ridge shifts a bit further east and surface winds begin to veer to a more southerly direction, temperatures will slowly increase through the end of the week. High temps on Thursday will be in the middle to upper 70s, while readings on Friday will likely top the 80-degree mark. After sunny skies today, moisture at around 850mb associated with an upper low meandering northward into the Mid-Atlantic states may get drawn into the area on Thursday and Friday. Forecast soundings and CU-rule both suggest increased diurnal cloudiness, yielding partly to mostly sunny skies both days. LONG TERM...Saturday through Tuesday Closed upper low over the Desert Southwest will lift northeastward into the Northern Plains/Upper Midwest over the weekend, pulling a cold front into Illinois. Models still disagree on speed of front, with GFS sticking to its faster solution and the ECMWF lagging about 12 hours behind. Exact speed will depend largely upon strength of Rex blocking that takes place along the East Coast over the next few days as persistent upper low undercuts ridge. Given presence of this feature, prefer the slower ECMWF solution in the extended. As such, will focus highest POPs along/ahead of the approaching front across the western half of the CWA during the day Saturday, then further east across the remainder of the area Saturday night. Will also hold on to low POPs across the E/SE into Sunday as front slowly departs into Indiana. Limited moisture ahead of the boundary and best upper dynamics remaining well to the north support only chance POPs for showers/thunder at this time. Further out, significant timing differences remain among the operational models. Once again, the GFS is much faster with the next approaching system than the ECMWF. Given highly amplified nature of upper trough digging into the Rockies/Plains late in the weekend, would tend to favor the slower ECMWF here as well. Will therefore maintain a warm/dry forecast for Monday before introducing a chance for showers and thunderstorms Monday night into Tuesday. After that, much cooler weather will arrive by the middle of next weeks with temps dropping below normal into the upper 50s/lower 60s by Wednesday. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
614 AM CDT WED OCT 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 232 AM CDT WED OCT 9 2013 IN RESPONSE TO STRENGTHENING WINDS ALOFT...SURFACE LOW PRESSURE HAS FORMED ACROSS ERN COLORADO SETTING UP AN STATIONARY FRONT AND INVERTED TROF FROM KOGA TO KVTN. A STRONG SOUTHWESTERLY LOW LEVEL JET SOUTH OF THIS FRONT WILL VEER OFF LATER THIS MORNING ALLOWING THE FRONT TO DROP SOUTH THIS AFTERNOON. THIS WILL PLACE MOST OF THE FCST AREA IN EAST OR NORTHEAST WINDS AND COOL AIR BY 21Z. THE MAX TEMPERATURE FORECAST CALLS FOR HIGHS IN THE 60S TO LOWER 70S BEHIND THE FRONT AND MID 70S ALONG AND AHEAD OF THE FRONT. THIS IS VERY CLOSE TO THE GEMREG...NAM12...HRRR AND RAP13 MODELS. THERE IS STILL SOME SNOW ON THE GROUND ACROSS NORTHWEST SHERIDAN COUNTY WHICH COULD KEEP HIGHS IN THE UPPER 50S. THE GFS AND RAP MODELS SHOW A BREAK IN THE CIRRUS TODAY. THE GFS SHOWS ANOTHER BATCH MOVING IN TONIGHT. THE MAIN LIMITATION ON HIGH TEMPERATURES TODAY WOULD APPEAR TO BE VERTICAL MIXING AND WEAK COLD AIR ADVECTION BEHIND THE SFC FRONT. OTHERWISE LIGHT WINDS ARE EXPECTED TODAY AND TONIGHT WITH THE FRONT BASICALLY ON TOP OF THE FORECAST AREA. A MULTIMODEL ENSEMBLE FORECAST SHOWS DEW POINTS RISING INTO THE MID AND UPPER 40S THIS AFTERNOON AND TONIGHT. THIS SHOULD KEEPS LOWS IN THE 40S TO LOWER 50S TONIGHT. SOME STRATUS MAY DEVELOP BEHIND THE FRONT ACROSS THE NORTHWEST THIS AFTERNOON AS A RESULT OF MIXING PROCESSES TO AROUND 800 MB. THESE CLOUDS DISSIPATE WITH THE LOSS OF DAYTIME HEATING TONIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 232 AM CDT WED OCT 9 2013 AN ACTIVE PERIOD...WITH TWO WEATHER MAKERS EXPECTED TO AFFECT WESTERN AND NORTH CENTRAL NEBRASKA. HIGH CONFIDENCE EXISTS WITH THE FIRST SYSTEM TO MOVE THROUGH THURSDAY NIGHT INTO FRIDAY...WITH NEARLY ALL GFS ENSEMBLE MEMBERS IN AGREEMENT ON THE TRACK OF THE NEGATIVELY TILTED 500 MB TROUGH. CONFIDENCE IS LOWER WITH THE SECOND SYSTEM SET TO ARRIVE EARLY NEXT WEEK. MORE ON THE SECOND SYSTEM LATER. AS MENTIONED...ENSEMBLES AND OPERATIONAL MODELS ARE IN VERY GOOD AGREEMENT WITH THE TRACK AND TIMING OF THE SYSTEM TO AFFECT THE REGION THURSDAY NIGHT INTO FRIDAY...AND INGREDIENTS FOR AN EPISODE OF SEVERE THUNDERSTORMS SEEMS INCREASINGLY FAVORABLE. ALOFT...A SIGNIFICANT NEGATIVELY TILTED SHORTWAVE TROUGH WILL QUICKLY TRACK FROM THE FOUR CORNERS AREA TO WESTERN NEBRASKA THURSDAY AFTERNOON THROUGH FRIDAY MORNING. AHEAD OF THIS FEATURE...A DEEPENING SURFACE LOW ACROSS EASTERN COLORADO THURSDAY AFTERNOON WILL HELP DRAW INCREASINGLY MOIST AIR NORTH FROM THE SOUTHERN PLAINS. BY EARLY EVENING MIXED LAYER DEW POINTS AT 500 METERS ARE IN THE 50 TO 55F DEGREE RANGE...WITH 850 MB DEW POINTS AT LEAST 10C IN MOST OPERATIONAL MODELS. IT APPEARS THAT THE ARRIVAL OF STRONG FORCING/COOLING ALOFT WILL COINCIDE WITH PEAK HEATING ACROSS EASTERN COLORADO...WHERE STORMS WILL FORM RAPIDLY ALONG AN ADVANCING PACIFIC COLD FRONT. THE 09/00Z NAM MODEL SUGGESTS A PLUME OF STEEP LOW LEVEL LAPSE RATES WILL EXIST TO THE EAST OF THESE STORMS ACROSS WESTERN NEBRASKA AND WESTERN KANSAS. THESE STEEP LOW LEVEL LAPSE RATES...IN COMBINATION WITH STEEP MID LEVEL LAPSE RATES AND INCREASINGLY MOIST AIR...SHOULD ENSURE AN ENVIRONMENT FAVORABLE FOR THESE THUNDERSTORMS TO SPREAD EAST. UPPER AIR FORECAST SOUNDING AT NORTH PLATTE BY MID EVENING INDICATES WINDS VEERING FROM SOUTHEAST IN THE LOWEST LEVELS...TO SOUTH-SOUTHWEST IN THE MID LEVELS...AND SOUTHWEST IN THE UPPER LEVELS. THE TREND HAS BEEN FOR A BIT MORE DIRECTIONAL SHEAR...AS WINDS VEER A BIT MORE IN THE MID LEVELS THAN PREVIOUS MODEL RUNS WERE INDICATING. THIS COULD HELP KEEP STORMS A BIT MORE DISCRETE...BUT OVERALL IT STILL APPEARS THAT A SQUALL LINE WITH WIND DAMAGE POTENTIAL WILL EVENTUALLY EVOLVE DURING THE EVENING ALONG THE EASTWARD ADVANCING PACIFIC COLD FRONT. IF STORMS WOULD HAPPEN TO STAY A BIT MORE DISCRETE...THEN A TORNADO POTENTIAL CANNOT BE RULED OUT...AS STORMS SPREAD EAST INTO AN AREA OF HIGH HELICITY VALUES. IN FACT...DO TO THE STRONG LOWER TROPOSPHERIC WINDS AND DIRECTIONAL SHEAR...0 TO 3 KM HELICITY VALUES INCREASE TO NEAR 500 M2/S2 BY MID EVENING THURSDAY NIGHT AT NORTH PLATTE. WHILE THE ENVIRONMENT ACROSS WESTERN/SOUTHWEST NEBRASKA LOOKS FAVORABLE FOR SEVERE THUNDERSTORMS...THE EASTWARD EXTENT OF THIS ENVIRONMENT IS LIMITED. AT THIS TIME IT APPEARS THE SEVERE THREAT WITH THE STORMS MAY DECREASE TO NEAR ZERO BY THE TIME THE STORMS MOVE INTO THE EASTERN PORTIONS OF THE FORECAST AREA AROUND BARTLETT AND ONEILL. AFTER THE SEVERE POTENTIAL THURSDAY EVENING...THE NEXT CONCERN IS WIND POTENTIAL ON THE SOUTHERN SIDE OF THE SYSTEM LATE THURSDAY NIGHT INTO FRIDAY. 09/00Z NAM DEEPENS THE SURFACE LOW TO NEAR 989 MB ACROSS NORTHERN SOUTH DAKOTA BY NOONTIME FRIDAY. 500 METER WIND SPEEDS INCREASE TO AROUND 33 KTS FOR A TIME FRIDAY MORNING...WHICH COULD SUPPORT NEAR WIND ADVISORY SPEEDS AT THE SURFACE. WINDS DECREASE DURING THE AFTERNOON AS THE LOW PRESSURE SYSTEM LIFT NORTH AWAY FROM THE AREA. THE WEEKEND IS LOOKING NICE...AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA AHEAD OF THE NEXT SYSTEM SET TO ARRIVE MONDAY. THE 09/00Z GFS ENSEMBLE MEAN IS NOW SHOWING THIS SYSTEM POTENTIALLY COMING THOUGH AS A CLOSED SYSTEM...LIKE THE 08/12Z AND 09/00Z RUNS OF THE ECMWF SHOW. WILL TREND THE FORECAST IN THE DIRECTION OF THE ECMWF...AS IT HAS THE SUPPORT OF THE GFS ENSEMBLE. THIS WOULD BRING A GOOD CHANCE FOR RAIN MONDAY AND MONDAY NIGHT TO THE AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 614 AM CDT WED OCT 9 2013 VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. SFC LOW PRESSURE WILL REMAIN STATIONARY ACROSS ERN COLORADO AND THIS WILL PRODUCE LIGHT WINDS ACROSS THE FORECAST AREA. THE GFS AND NAM MODELS SHOW SOME BKN-OVC040 CIGS DEVELOPING THIS AFTN NEAR KVTN. THE RAP MODEL SHOWS THESE CIGS NEAR 3KFT AGL. EITHER WAY ALL MODELS DISSIPATE THESE CIGS WITH THE LOSS OF DAYTIME HEATING THIS EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS SPOKANE WA
457 AM PDT Wed Oct 9 2013 .SYNOPSIS... A cool but drier weather pattern is expected today through Friday. The chance for precipitation will increase over the weekend with the arrival of another low pressure system. Drier conditions are expected to return at the start of the new week. && .DISCUSSION... Today and tonight...Cold core upper level low responsible for yesterday round of widespread showers and isolated thunderstorms continues to sag southward this morning with swift north-northeast oriented jet taking its place over the region. The jet was associated with the front edge of a building upper level ridge and will continue to make slow eastward progress over the Inland Northwest today and tonight. The main result of this transition will be a surge of drier air into the region and little if any chance of precipitation. The atmosphere will be considerably more stable than yesterday as 500 mb temps warm about 15-20c compared to yesterday which will vastly outpace the 3-6c of warming below 850 mbs. The low level warming will result in high temperatures in the mid 50s to mid 60s which is still around 5 degrees below the seasonal normals. For tonight...the ridge will continue to ease eastward with an elongated occluded front expected to push into the NW part of the forecast area late tonight. Locations from the Okanogan Highlands to the north Cascades will definitely see an increasing cloud trend overnight...but whether rainfall occurs will be the question. Model cross-sections suggest that if precipitation were to occur it would be limited to locations near the immediate crest late tonight...but the SREF would suggest any measurable precipitation will hold off until daybreak. The increasing clouds will decrease the radiational cooling potential overnight...while a more desiccated boundary layer should keep the chances for valley fog considerably less than what could form this morning. fx Thurs through Tue: We`ll only have to deal with two pcpn- producing waves during the mid and extended range part of this fcst cycle...the first one Thurs and the second (wetter) feature Saturday. For Thurs, the majority of region will be under the post-frontal dry slot characterized by occasionally gusty winds. The highest pcpn threat will be along the border with BC, especially in the afternoon as the trailing vort max and accompanying steep mid- level lapse rates produce a favorable environment for mainly late day showers. A very brief window of opportunity for these showers, however. After this, the next short- wave trough will track through the region Fri Nt and Saturday. Though this will potentially be much wetter than the Thurs front, the trend has been one of less amplification of the steering flow, leading to a quicker transit time, less instability, and less forcing for ascent. Even so, all of N Idaho and much of Ern Wa should see some rain. Snow levels will be too high to cause any issues for regional passes. Unfortunately again, confidence in the timing and strength of this feature is low 4-5 days out, especially given the model differences presented.bz && .AVIATION... 12Z TAFS: Low confidence forecast at least through 17-18z or so for the GEG-SFF-COE corridor as satellite fog product was detecting widespread low clouds over the NE corner of WA and the northern ID Panhandle. Visibilities and cigs below this deck will generally be IFR but brief breaks are possible. Conditional climatology suggests the clouds should lift and fog break up around 17z...and this notion is supported by the latest HRRR model. Thus confidence is high that we should see VFR conditions at these sites before midday. Other problem spot is LWS and PUW where satellite shows clouds rapidly expanding. Not sure on cigs quite yet since not impacting any nearby airports...but MVFR/IFR cigs are certainly possible. Once the clouds break up at all these sites...we should see widespread VFR conditions for the last half of the forecasts as ridging builds over the region. fx && .PRELIMINARY POINT TEMPS/POPS... Spokane 56 38 57 37 55 38 / 0 0 10 0 0 10 Coeur d`Alene 57 37 57 37 55 38 / 0 0 10 0 0 10 Pullman 58 37 55 35 55 38 / 0 0 10 10 0 10 Lewiston 61 42 59 40 60 41 / 0 0 10 10 0 10 Colville 59 37 59 36 58 36 / 0 0 10 0 0 10 Sandpoint 56 35 55 35 55 36 / 0 0 10 20 10 10 Kellogg 54 36 51 37 51 36 / 0 0 20 20 10 10 Moses Lake 63 39 64 36 62 38 / 0 0 0 0 0 10 Wenatchee 62 41 63 40 61 39 / 0 0 0 0 0 10 Omak 62 35 62 34 61 34 / 0 0 10 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
703 AM CDT WED OCT 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM CDT WED OCT 9 2013 MAIN SHORT TERM FORECAST CONCERNS ARE ON WINDS AND TEMPERATURES TODAY. CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEPENING TROUGHING OVER THE WESTERN U.S. AND STRENGTHENING RIDGING FROM LOUISIANA INTO THE GREAT LAKES. THE SOUTHWEST FLOW BETWEEN THESE FEATURES HAS BEEN BRINGING A VARIETY OF WEAK SHORTWAVES TOWARDS THE FORECAST AREA. HOWEVER...DUE TO PLENTIFUL DRY AIR IN THE LOW TO MID LEVELS OF THE TROPOSPHERE AS EVIDENCED ON 00Z SOUNDINGS FROM DDC TO OAX AND MPX...THE SHORTWAVES HAVE BEEN ONLY ABLE TO PRODUCE SCT-BKN CIRRUS CLOUDS. OF SOMEWHAT MORE SIGNIFICANCE IS THE STRENGTH OF THE LOW LEVEL SOUTHWEST FLOW. AHEAD OF A COLD FRONT DRAPED FROM NORTHWEST MN INTO WESTERN NEBRASKA PER SURFACE ANALYSIS...35-50 KT SOUTHWEST 850MB WINDS WERE PRESENT FROM WESTERN KANSAS THROUGH THE FORECAST AREA AND INTO UPPER MICHIGAN. SOME OF THIS BREEZE EXTENDS DOWN THE SURFACE...HELPING TO KEEP TEMPERATURES WELL ABOVE NORMAL DESPITE SURFACE DEWPOINTS IN THE MID 40S. OVER THE NEXT 24 HOURS...MODELS ARE IN GOOD AGREEMENT OF THE WESTERN TROUGH DIGGING DEEPER...FEATURING AN UPPER LOW IN THE VICINITY OF LAS VEGAS BY 12Z THURSDAY. MEANWHILE...THE UPPER RIDGE DOWNSTREAM STRENGTHENS FURTHER TO HELP BALANCE THE DEEPER WESTERN TROUGH... RESULTING IN A BLOCKED UP PATTERN. THUS...THAT FRONTAL BOUNDARY FROM NORTHWEST MN INTO WESTERN NEBRASKA GOES NOWHERE AND THE FORECAST AREA STAYS IN DRY LOW TO MID LEVEL SOUTHWEST FLOW. THE PRESSURE GRADIENT MAGNITUDE...A MEASURE OF HOW TIGHT THE PRESSURE GRADIENT IS...MODELS PROG TO BE 40-50 PERCENT LESS THAN YESTERDAY. SO ALTHOUGH MIXING AND MAINTAINING A DECENT PRESSURE GRADIENT STILL SUGGESTS BREEZY CONDITIONS...ESPECIALLY WEST OF THE MISSISSIPPI RIVER...EXPECT WINDS TO NOT BE AS GUSTY AS YESTERDAY. 925MB TEMPERATURES TODAY ARE FORECAST ABOUT 2C COOLER COMPARED TO YESTERDAY...RANGING FROM 14-16C VERSUS THE 17-20C OBSERVED FROM 00Z SOUNDINGS. IT APPEARS THE REASON FOR THE COOLER CONDITIONS IS THE LOW LEVEL FLOW BACKING MORE SOUTHERLY. THEREFORE...HIGHS ARE LIKELY TO BE A FEW DEGREES COOLER. A SOUTHERLY BREEZE LOOKS TO PERSIST TONIGHT...BUT NOT AS STRONG AS THIS MORNING. THIS MEANS THE TYPICAL COLD SPOTS IN WISCONSIN STAND A MUCH BETTER CHANCE OF DECOUPLING AND DROPPING CLOSER TO THE DRIER DEWPOINTS IN PLACE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 225 AM CDT WED OCT 9 2013 MAIN LONG TERM FORECAST CONCERNS ARE ON WINDS FRIDAY AND POTENTIAL FOR PRECIPITATION FRIDAY THROUGH SATURDAY. SYNOPTIC OVERVIEW... MUCH OF THE FOCUS ON THE FORECAST REMAINS ON THE EVOLUTION OF THE WESTERN TROUGH...AND IN PARTICULAR THE UPPER LOW NEAR LAS VEGAS AT 12Z THURSDAY. GOOD MODEL AGREEMENT EXISTS THAT THE UPPER LOW WILL GET EJECTED OUT AND SHUNTED NORTH THROUGH THE DAKOTAS ON FRIDAY. FROM THERE INDICATIONS ARE THAT PHASING OCCURS WITH A SHORTWAVE TROUGH COMING THROUGH THE NORTHERN STREAM ACROSS SOUTH CENTRAL CANADA...RESULTING IN A FAIRLY DEEP LOW PRESSURE SYSTEM IN MANITOBA COME SATURDAY. THIS SYSTEM LIFTS OUT ON SUNDAY WHILE NEW TROUGHING RELOADS OVER THE WESTERN U.S.. THERE ARE PLENTY OF DISAGREEMENTS AMONGST THE MODEL HANDLING OF THIS NEW WESTERN TROUGH...PRIMARILY ITS PROGRESSION EAST WHERE THE 09.00Z GFS IS MUCH FASTER THAN THE 09.00Z CANADIAN/ECMWF AND 09.00Z CANADIAN ENSEMBLES. DETAILS... THURSDAY AND THURSDAY NIGHT WILL REMAIN DRY WITH THE BLOCKED UP PATTERN AHEAD OF THE WESTERN TROUGH. WINDS LOOK TO GRADUALLY INCREASE OUT OF THE SOUTH/SOUTHEAST AS WELL...IN RESPONSE TO DYNAMICAL FORCING DOWNSTREAM OF THE UPPER LOW EJECTING OUT CAUSING PRESSURES TO LOWER OVER THE PLAINS. 925MB TEMPS CLIMB ABOUT 1C FROM TODAY...RESULTING IN A SLIGHTLY WARMER DAY. MORE WIND AT NIGHT...ESPECIALLY ABOVE THE SURFACE...SHOULD HELP TO PRODUCE A WARMER NIGHT AS WELL. FRIDAY REMAINS A DAY TO FOCUS ON WINDS. AS THE UPPER AND SURFACE LOWS LIFT THROUGH THE DAKOTAS ON FRIDAY...THE PRESSURE GRADIENT TIGHTENS FURTHER OVER THE FORECAST AREA. THE MAGNITUDE OF THE GRADIENT IS ON PAR WITH THAT SEEN YESTERDAY...EXCEPT ALL OF THE FORECAST AREA SEES THE STRONGER GRADIENT VERSUS JUST WEST OF THE MISSISSIPPI RIVER. THUS A WINDY DAY IS LIKELY EVERYWHERE... ESPECIALLY IN HIGHER TERRAIN EXPOSED LOCATIONS. MIXING ON FORECAST SOUNDINGS FROM THE 09.00Z GFS/NAM SUGGEST WIND ADVISORY CRITERIA COULD BE REACHED IN THOSE LOCATIONS...SUCH AS DODGE CENTER AND ROCHESTER MN. THE WINDS ALSO HELP DRIVE UP 925MB TEMPS TO 16-18C...SUPPORTING HIGHS AS MUCH AS THE MID TO UPPER 70S DEPENDING ON AMOUNT OF SUNSHINE. LATE FRIDAY THROUGH SATURDAY FOCUS SWITCHES TO PRECIPITATION POTENTIAL. SOUTHERLY FLOW AHEAD OF THE UPPER AND SURFACE LOWS HEADING UP INTO MANITOBA HELPS TO DRAW HIGHER PRECIPITABLE WATER VALUES INTO THE FORECAST AREA. VALUES ARE PROGGED TO REACH 1-1.2 INCHES BY 00Z SATURDAY VERSUS THE 0.3-0.6 INCHES PRIOR TO THEN. THOSE VALUES ARE ACTUALLY 150-200 PERCENT OF NORMAL. THE QUESTION IS IF FORCING EXISTS TO ACT ON THE MOISTURE TO SQUEEZE OUT SOME RAIN. THE TRACK OF THE UPPER LOW IS UNDESIRABLE...KEEPING THE DPVA FORCING FROM IT NORTHWEST OF THE AREA. A SMALL PORTION OF THE WARM CONVEYOR BELT AHEAD OF THE UPPER LOW MAY BRUSH WESTERN PORTIONS OF THE FORECAST AREA LATE FRIDAY WITH SOME LIGHT RAIN SHOWERS OR SPRINKLES...BUT THIS IS A LOW CHANCE. FRIDAY NIGHT MAY STAND TO HAVE THE GREATEST CHANCE OF RAIN...IF THE 09.00Z CANADIAN MODEL FORECAST IS CORRECT. THE MODEL BRINGS UP A STRONGER SHORTWAVE THAN INDICATED BY ALL OTHER MODELS THROUGH THE SOUTHWEST FLOW INTO IOWA BY 12Z SATURDAY. THIS SHORTWAVE HELPS TIGHTEN UP THE FRONTOGENESIS AROUND A COLD FRONTAL BOUNDARY MAKING ITS WAY THROUGH THE FORECAST AREA... LEADING TO A BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS. MEANWHILE...THE 09.00Z GFS/NAM POINT TO A DRY OR MOSTLY DRY SCENARIO. FOR NOW HAVE MAINTAINED 20 PERCENT CHANCES OF SHOWERS AND THUNDERSTORMS BUT WOULD NOT BE SURPRISED TO HAVE TO CHANGE TO A DRY FORECAST. SATURDAY IS STILL UP IN THE AIR...WITH THE 09.00Z GFS/CANADIAN AND 08.12Z ECMWF TRENDING DRIER...SUGGESTING ANY ADDITIONAL FRONTOGENETIC OR INSTABILITY FORCING ALONG THE COLD FRONT OCCURS MOSTLY EAST OF THE FORECAST AREA. HOWEVER...THE 09.00Z ECMWF CAME BACK SHOWING THIS FORCING OCCURRING FARTHER WEST...ENCOMPASSING THE SOUTHEAST HALF OF THE AREA IN PRECIPITATION. THUS CHANCES OF PRECIPITATION NEED TO REMAIN IN THE FORECAST FOR SATURDAY. LOOKING FARTHER AHEAD...THE ONLY FEATURE OF NOTE WILL BE A LOW PRESSURE SYSTEM THAT DEVELOPS OVER THE PLAINS SUNDAY INTO MONDAY... ASSOCIATED WITH THE NEW WESTERN TROUGH. MUCH UNCERTAINTY EXISTS ON WHEN THE SYSTEM EVENTUALLY IMPACTS THE REGION...THEREFORE...HAVE FOLLOWED A MODEL CONSENSUS FOR TEMPERATURES AND PRECIPITATION CHANCES. IT DOES APPEAR RIGHT NOW THAT THE FORECAST AREA WILL LIE ON THE NORTH/COOL SIDE OF THE SYSTEM...WHICH WOULD SUGGEST A GREATER CHANCE OF SEEING RAIN. FOR WHAT ITS WORTH...THE 09.00Z GFS REALLY DEEPENS THE SYSTEM ENOUGH TO ALLOW FOR A RAIN/SNOW MIX...BUT THIS SOLUTION IS VERY HARD TO TRUST GIVEN THE MODEL UNCERTAINTY. && .AVIATION...TODAY AND TONIGHT 703 AM CDT WED OCT 9 2013 VFR CONDITIONS FOR THE TAF LOCATIONS FOR THE NEXT 24 HOURS. ONLY POTENTIAL ISSUES FOR AVIATION INTERESTS ARE WIND SPEEDS TODAY...COULD BE A BIT GUSTY...AND PERHAPS SOME PATCHY VALLEY STRATUS EARLY THURSDAY MORNING NEAR KLSE. FEEL WINDS WILL STAY UP ENOUGH TO PROVIDE MIXING TO PREVENT THE VALLEY FROM FILLING UP WITH FOG/STRATUS...BUT THE NOCTURNAL INVERSION COULD BE JUST ENOUGH TO ALLOW PATCHES OF STRATUS TO DEVELOP. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...MW
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1239 PM CDT WED OCT 9 2013 .DISCUSSION... 1106 AM CDT MORNING UPDATE... FORECAST APPEARS TO BE LARGELY ON TRACK...WITH EXPANSIVE HIGH PRESSURE STRETCHING FROM NEW ENGLAND TO THE CENTRAL GREAT LAKES PROVIDING ANOTHER PLEASANT DAY. 12Z RAOB SHOWED 925 MB TEMPS A FEW DEGREES COOLER THAN YESTERDAY...WHICH SHOULD SUPPORT GOING HIGHS IN THE LOWER AND MID 70S...A FEW DEGREES COOLER THAN YESTERDAY. THIS IS DESPITE H85 TEMPS A FEW DEGREES WARMER THAN TUES SINCE FORECAST SOUNDINGS INDICATE MIXING ONLY UP TO ABOUT 925 MB. MAIN CHANGE WAS TO LOWER IL LAKEFRONT HIGHS 3 TO 5 DEGREES AS WINDS HAVE ALREADY TURNED EASTERLY ALONG COOK COUNTY SHORE. WITH DOWNTOWN CHICAGO ONLY AT 61 DEGREES AS OF THIS WRITING...HIGHS ONLY EXPECTED TO CLIMB TO THE MID 60S. RC //PREV DISCUSSION... 310 AM CDT TODAY THROUGH TONIGHT... HIGH PRESSURE CONTINUES TO BE THE MAIN COMPONENT GUIDING THE WEATHER FOR THE NEXT 48 HOURS...WHICH WILL LIKELY AID IN ABOVE SEASONAL TEMPERATURES FOR THE REGION THROUGH THE END OF THE WEEK. TODAY WILL BE NEARLY A CARBON COPY OF YESTERDAY. CLOUDLESS SKIES EARLY THIS MORNING ACROSS NORTHERN IL/NORTHWEST IN...WITH IR IMAGERY INDICATING JUST A FEW CIRRUS CLOUDS FLOATING NORTHEAST ACROSS CENTRAL WISC STRETCHING SOUTHWEST THROUGH THE CENTRAL PLAINS. SFC WINDS HAVE HELD UP OVERNIGHT FROM THE SOUTHEAST...WHICH HAS BEEN RESPONSIBLE FOR MAINTAINING TEMPS IN THE UPR 40S TO LOW 50S ACROSS THE FORECAST AREA. HOWEVER EXPECT WINDS TO DECREASE JUST BEFORE DAYBREAK AND ALLOW TEMPS TO RADIATE A FEW DEGREES INTO THE LOW/MID 40S. CURRENT T/TD SPREADS ARE LARGE ENOUGH THAT SHALLOW FOG IS PROBABLY NOT GOING TO FORM...HOWEVER JUST BEFORE DAYBREAK IF THE TEMPS ARE ABLE TO RADIATE FURTHER THEN A FEW LOCATIONS MAY SEE SHALLOW FOG DEVELOP. BROAD ANTI-CYCLONIC FLOW CENTERED OVER THE OHIO VALLEY WILL CONTINUE TO PROVIDE A SIGNIFICANT INFLUENCE ON THE SENSIBLE WEATHER FOR THE CWFA TODAY. TEMPS ALOFT ARE PROGGED TO RANGE BETWEEN 12-14 DEG C AT 850MB. THIS COUPLED WITH MINIMAL SPREAD AMONGST TEMP PLUMES FOR A HANDFUL OF POINTS SUGGESTS THAT LESS MIXING WILL TAKE PLACE TODAY AND TEMPS WILL LIKELY BE IN THE LOW 70S...POSSIBLY MID 70S ALONG AND SOUTH OF A LASALLE TO KANKAKEE LINE. THEN TONIGHT SKIES REMAIN MOSTLY CLEAR WITH A LIGHT SOUTH/SOUTHEAST FLOW AT THE SFC. TEMPS WILL AT FIRST RADIATE INTO THE MID/UPR 50S JUST AFTER SUNSET...THEN SLOWLY COOL THROUGH THE REMAINDER OF THE OVERNIGHT INTO THE MID/UPR 40S. NEAR DOWNTOWN CHICAGO IN THE MID 50S. CONFIDENCE...HIGH. THURSDAY THROUGH SATURDAY... ANOMALOUS MID-LVL TROUGH CONTINUES TO BE PROGGED TO DIG INTO THE FOUR-CORNERS REGION OF THE CONUS EARLY THURSDAY. THIS FEATURE WILL LIKELY FURTHER AMPLIFY THE DOWNSTREAM RIDGE OVER THE GREAT LAKES REGION. ENSEMBLES CONTINUE TO SUGGEST THE RIDGE OVER THE GREAT LAKES WILL DRIFT EAST AND BECOME CENTERED OVER EASTERN ONTARIO/WESTERN QUEBEC THUR...THEN UNDERGO SOME STRENGTHENING. WITH THE WAVE SHOWING SIGNS OF STRENGTHENING FRI INTO SAT VERIFIES...THIS WILL LIKELY DEFLECT THE UPCOMING WEEKEND SHORTWAVE FURTHER NORTHWEST AWAY FROM THE FORECAST AREA. GUIDANCE HAS CONTINUED TO BACK OFF ON PRECIP TIMING AS WELL AS COVERAGE. SFC RIDGING APPEARS TO HOLD ONTO THE REGION THROUGH FRI...AND MID-LVL HEIGHTS ARE STILL SHOWING SOME SIGNS OF RESISTANCE TO THE PROGGED 500MB TROUGH THAT WILL SLIDE EAST FOR THE UPCOMING WEEKEND. AT PRESENT HAVE PUSHED PRECIP OFF UNTIL EARLY SAT MORNING. INSTABILITY DOES NOT LOOK TO BE VERY IMPRESSIVE LATE FRI NIGHT/SAT...WITH PRESENT GUIDANCE INDICATING MUCAPE VALUES STRUGGLING TO REACH 400J/KG. WHILE SOME UNCERTAINTY REMAINS WITH THE UPCOMING SYSTEM...HAVE OPTED TO TRIM BACK MENTION OF THUNDER FROM CHANCE TO SLIGHT CHANCE. TEMPS WILL CONTINUE TO WARM IN ADVANCE OF THE WEEKEND SYSTEM...WITH GUIDANCE TRENDING WELL ABOVE NORMAL WITH HIGHS IN THE MID 70S THUR. GIVEN THE LACK OF CLOUD COVER...AND SOME AFTERNOON MIXING...PARCEL HEAT CAPACITY WILL REMAIN MINIMAL. THIS WILL SUPPORT THE SCENARIO OF AFTN TEMPS FRI WARMING WELL INTO THE 70S...AND CAN NOT RULE OUT AN 80 DEG FOR THE SOUTHERN PORTIONS OF THE CWFA. LLVL MOISTURE WILL ALSO BE ON THE INCREASE LATE WEEK/EARLY WEEKEND...WITH DEW POINTS INCREASING INTO THE MID/UPR 50S. THE ADDED MOISTURE AND INCREASING CLOUDS WILL KEEP OVERNIGHT LOWS FRI NIGHT/EARLY SAT FROM COOLING MUCH...SO HAVE BUMPED TEMPS INTO THE MID/UPR 50S. ABUNDANT CLOUD COVER SAT WILL HELP HOLD TEMPS IN THE LOW/MID 70S...WITH THE EXCEPTION OF THE SOUTHEAST CWFA WHERE TEMPS COULD YET AGAIN WARM INTO THE UPR 70S. IF THE APPROACHING SYSTEM SLOWS OR HAS LESS CLOUD COVER ASSOCIATED...THEN TEMPS SAT WILL WARM INTO THE MID/UPR 70S ACROSS THE CWFA. CONFIDENCE IN TEMPERATURES...HIGH. CONFIDENCE IN PRECIP SAT...MEDIUM. SUNDAY THROUGH TUESDAY... ENSEMBLES CONTINUE TO DEMONSTRATE MINIMAL SPREAD IN THE LONG TERM PERIOD...SUGGESTING INCREASED CONFIDENCE IN THE LONG WAVE PATTERN. THE 3 SIGMA RIDGE OVER ONTARIO/QUEBEC WILL BEGIN TO WEAKEN SUN/MON...WITH THE UPSTREAM TROUGH WEAKENING AND BECOMING SEMI-ZONAL. A LARGE FEATURE THAT IS PROGGED TO DEVELOP IS CONSIDERABLE BLOCKING ACROSS THE NORTH ATLANTIC...WHICH COULD CREATE A BOTTLENECK IN THE PATTERN FOR THE CONUS. CURRENT OPERATIONAL SOLUTIONS CONTINUE TO BE PROGRESSIVE WITH THE EARLY WEEKEND SYSTEM PUSHING THROUGH THE FORECAST AREA SUN MORNING...WHICH SHOULD BRING A RETURN TO SEASONAL TEMPS AND DRY WEATHER FOR MIDDAY SUN THROUGH MON. THE GFS/EC ARE IN DISAGREEMENT EARLY NEXT WEEK...WITH THE GFS REMAINING PROGRESSIVE AND DEVELOPING A ROBUST SHORTWAVE ACROSS THE CENTRAL PLAINS ALONG A QUASI-STATIONARY BOUNDARY. THIS FEATURE IS PROGGED TO REACH THE WESTERN GREAT LAKES LATE MON/TUE. THE EC HAS A SIMILAR SOLUTION...ONLY DEMONSTRATING A SLOWER DEVELOPMENT AND NOT ARRIVING UNTIL TUE/WED. CONFIDENCE...MEDIUM. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... LIGHT LAKE BREEZE WILL BE SUPERIMPOSED ON THE WEAK SOUTHEAST LOW LEVEL SYNOPTIC SCALE FLOW OVER THE AREA THIS AFTERNOON RESULTING IN A BACKING OF WINDS TO EAST-SOUTHEAST AND EAST. TRS //DISCUSSION...UPDATED 18Z... MODELS MAINTAIN THE SURFACE RIDGE AXIS ALIGNED WESTWARD ACROSS THE LOWER GREAT LAKES AND SOUTHERN LAKE MICHIGAN THIS AFTERNOON...WITH THE WESTERN PORTION DROPPING SOUTHWARD ACROSS FAR NORTHERN THURSDAY INDIANA. THIS WILL MAINTAIN A WEAK EAST-SOUTHEAST TO SOUTHEAST LOW LEVEL SYNOPTIC FLOW OVER THE LOCAL AREA. WITH LAKE WATER TEMPERATURES IN THE UPPER 50S TO MID 60S AND INLAND SURFACE TEMPERATURES EXPECTED TO RISE INTO THE LOWER 70S THIS AFTERNOON AND THE LOWER TO MID 70S THURSDAY AFTERNOON THERE IS ENOUGH TEMPERATURE DIFFERENTAL FOR A WEAK LAKE BREEZE TO BE SUPERIMPOSED ON TOP OF THE SYNOPTIC FLOW. THIS IS ALREADY SEEN OCCURRING ALONG THE LAKE SHORE WITH COASTAL MARINE OBSERVATION SITES ALL SHOWING A BACKING OCCURRING BETWEEN 16Z AND 17Z. HIGH RESOLUTION SHORT RANGE MODEL GUIDANCE SHOWS THIS VEERING MOVING WESTWARD ACROSS THE TERMINALS LATER THIS AFTERNOON. WITH THE LOSS OF HEATING AS DUSK APPROACHES TEMPERATURES IN THE DRY AIR MASS WILL QUICKLY DROP OFF EARLY THIS EVENING AND THE LAKE BREEZE WILL DISSIPATE. PRETTY MUCH THE SAME SCENARIO FOR THURSDAY WITH SOUTH-SOUTHEAST WINDS BACKING AGAIN IN THE AFTERNOON AS TEMPERATURES RISE. VERY DRY AIR MASS ASSOCIATED WITH THE RIDGE FROM SURFACE TO UPPER LEVELS OVER THE REGION CERTAINLY PRECLUDES CLOUDS OF ANY SIGNIFICANCE...AND LITTLE IF ANY AT ALL. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH ALL ELEMENTS. TRS //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... * THURSDAY NIGHT AND FRIDAY...DRY/VFR. * SATURDAY...CHANCE OF SHRA/TSRA. * SUNDAY...DRY/VFR. * MONDAY AND TUESDAY...SLIGHT CHANCE OF SHRA. && .MARINE... 226 AM...WHILE HIGH PRESSURE IS CENTERED OVER NEW ENGLAND EARLY THIS MORNING...A LARGE WEAKER RIDGE EXTENDS SOUTHWEST ACROSS THE OHIO VALLEY. AS THE CENTER OF THIS HIGH MOVES EAST OVER THE ATLANTIC TODAY AND TONIGHT...THIS RIDGE WILL DRIFT NORTHEAST AND REMAIN ACROSS MUCH OF THE CENTRAL/EASTERN LAKES REGION INTO FRIDAY...WHEN IT WILL BE REINFORCED BY A STRONGER HIGH MOVING SOUTHEAST ACROSS QUEBEC FRIDAY/FRIDAY NIGHT. MEANWHILE... LOW PRESSURE OVER WESTERN ONTARIO WILL CONTINUE TO WEAKEN AS IT MOVES NORTHEAST INTO WESTERN QUEBEC THIS EVENING. HOWEVER...THE GRADIENT WILL REMAIN TIGHT OVER THE NORTHERN HALF OF LAKE MICHIGAN INTO THIS AFTERNOON THEN BEGIN TO WEAKEN SOME TONIGHT. ANOTHER AREA OF LOW PRESSURE OVER COLORADO IS EXPECTED TO MOVE NORTHEAST ACROSS THE PLAINS THURSDAY NIGHT AND FRIDAY REACHING SOUTHERN MANITOBA FRIDAY NIGHT. SOUTHERLY WINDS WILL ONCE AGAIN INCREASE AS THIS SYSTEM MOVES NORTH...BUT THE STRONGEST WINDS SHOULD REMAIN WEST OF LAKE MICHIGAN. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO DISCLAIMER: NWS FACEBOOK...TWITTER AND YOUTUBE SITES ARE NOT CONSIDERED OFFICIAL MEANS OF DISSEMINATING WEATHER INFORMATION AND SHOULD NOT BE COUNTED ON AS SUCH. OFFICIAL NWS.NOAA.GOV WEB SITES ARE MOST RELIABLE IN PROVIDING TIMELY DELIVERY OF DATA AND PRODUCTS BUT EVEN THESE SOURCES CANNOT BE GUARANTEED DUE TO THE NATURE OF THE INTERNET.
Area Forecast Discussion National Weather Service Lincoln IL 1209 PM CDT Wed Oct 9 2013 .DISCUSSION... ISSUED 950 AM CDT Wed Oct 9 2013 Illinois remaining on the periphery of the high pressure that was centered in New England this morning. Latest satellite imagery showing some stratocumulus spreading northward through southern Illinois. Latest RAP model humidity plot for 925-850 mb shows some of this creeping up to around I-64 this afternoon, but mainly sunny skies will prevail over the CWA. Have sent some updated grids to refresh the hourly temperature and dew point trends, but no changes needed to the zones at this time. Geelhart && .AVIATION... ISSUED 1208 PM CDT Wed Oct 9 2013 VFR conditions to prevail through the TAF period. Little in the way of cloud cover on tap through about 09Z. After that, an increase in clouds around 4000 feet will occur from south to north as moisture advects northward. Cu-rule and soundings favor the most cloud cover in eastern Illinois with some broken ceilings. Would not be too surprised to see some very shallow fog in some spots early Thursday morning, similar to the past couple mornings, but confidence in extended visibility restrictions is not high enough to warrant inclusion in the TAFs at this point. Geelhart && .PREV DISCUSSION... ISSUED 238 AM CDT Wed Oct 9 2013 SHORT TERM...Today through Friday Sprawling high pressure extending from New England to the Southern Plains will dominate the weather across central Illinois over the next couple of days. With ridge axis overhead today, light E/SE winds and slightly lower mixing heights will result in high temps a degree or two cooler than yesterday...with readings generally topping out in the lower to middle 70s. Once the ridge shifts a bit further east and surface winds begin to veer to a more southerly direction, temperatures will slowly increase through the end of the week. High temps on Thursday will be in the middle to upper 70s, while readings on Friday will likely top the 80-degree mark. After sunny skies today, moisture at around 850mb associated with an upper low meandering northward into the Mid-Atlantic states may get drawn into the area on Thursday and Friday. Forecast soundings and CU-rule both suggest increased diurnal cloudiness, yielding partly to mostly sunny skies both days. LONG TERM...Saturday through Tuesday Closed upper low over the Desert Southwest will lift northeastward into the Northern Plains/Upper Midwest over the weekend, pulling a cold front into Illinois. Models still disagree on speed of front, with GFS sticking to its faster solution and the ECMWF lagging about 12 hours behind. Exact speed will depend largely upon strength of Rex blocking that takes place along the East Coast over the next few days as persistent upper low undercuts ridge. Given presence of this feature, prefer the slower ECMWF solution in the extended. As such, will focus highest POPs along/ahead of the approaching front across the western half of the CWA during the day Saturday, then further east across the remainder of the area Saturday night. Will also hold on to low POPs across the E/SE into Sunday as front slowly departs into Indiana. Limited moisture ahead of the boundary and best upper dynamics remaining well to the north support only chance POPs for showers/thunder at this time. Further out, significant timing differences remain among the operational models. Once again, the GFS is much faster with the next approaching system than the ECMWF. Given highly amplified nature of upper trough digging into the Rockies/Plains late in the weekend, would tend to favor the slower ECMWF here as well. Will therefore maintain a warm/dry forecast for Monday before introducing a chance for showers and thunderstorms Monday night into Tuesday. After that, much cooler weather will arrive by the middle of next weeks with temps dropping below normal into the upper 50s/lower 60s by Wednesday. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1106 AM CDT WED OCT 9 2013 .DISCUSSION... 1106 AM CDT MORNING UPDATE... FORECAST APPEARS TO BE LARGELY ON TRACK...WITH EXPANSIVE HIGH PRESSURE STRETCHING FROM NEW ENGLAND TO THE CENTRAL GREAT LAKES PROVIDING ANOTHER PLEASANT DAY. 12Z RAOB SHOWED 925 MB TEMPS A FEW DEGREES COOLER THAN YESTERDAY...WHICH SHOULD SUPPORT GOING HIGHS IN THE LOWER AND MID 70S...A FEW DEGREES COOLER THAN YESTERDAY. THIS IS DESPITE H85 TEMPS A FEW DEGREES WARMER THAN TUES SINCE FORECAST SOUNDINGS INDICATE MIXING ONLY UP TO ABOUT 925 MB. MAIN CHANGE WAS TO LOWER IL LAKEFRONT HIGHS 3 TO 5 DEGREES AS WINDS HAVE ALREADY TURNED EASTERLY ALONG COOK COUNTY SHORE. WITH DOWNTOWN CHICAGO ONLY AT 61 DEGREES AS OF THIS WRITING...HIGHS ONLY EXPECTED TO CLIMB TO THE MID 60S. RC && .PREV DISCUSSION... 310 AM CDT TODAY THROUGH TONIGHT... HIGH PRESSURE CONTINUES TO BE THE MAIN COMPONENT GUIDING THE WEATHER FOR THE NEXT 48 HOURS...WHICH WILL LIKELY AID IN ABOVE SEASONAL TEMPERATURES FOR THE REGION THROUGH THE END OF THE WEEK. TODAY WILL BE NEARLY A CARBON COPY OF YESTERDAY. CLOUDLESS SKIES EARLY THIS MORNING ACROSS NORTHERN IL/NORTHWEST IN...WITH IR IMAGERY INDICATING JUST A FEW CIRRUS CLOUDS FLOATING NORTHEAST ACROSS CENTRAL WISC STRETCHING SOUTHWEST THROUGH THE CENTRAL PLAINS. SFC WINDS HAVE HELD UP OVERNIGHT FROM THE SOUTHEAST...WHICH HAS BEEN RESPONSIBLE FOR MAINTAINING TEMPS IN THE UPR 40S TO LOW 50S ACROSS THE FORECAST AREA. HOWEVER EXPECT WINDS TO DECREASE JUST BEFORE DAYBREAK AND ALLOW TEMPS TO RADIATE A FEW DEGREES INTO THE LOW/MID 40S. CURRENT T/TD SPREADS ARE LARGE ENOUGH THAT SHALLOW FOG IS PROBABLY NOT GOING TO FORM...HOWEVER JUST BEFORE DAYBREAK IF THE TEMPS ARE ABLE TO RADIATE FURTHER THEN A FEW LOCATIONS MAY SEE SHALLOW FOG DEVELOP. BROAD ANTI-CYCLONIC FLOW CENTERED OVER THE OHIO VALLEY WILL CONTINUE TO PROVIDE A SIGNIFICANT INFLUENCE ON THE SENSIBLE WEATHER FOR THE CWFA TODAY. TEMPS ALOFT ARE PROGGED TO RANGE BETWEEN 12-14 DEG C AT 850MB. THIS COUPLED WITH MINIMAL SPREAD AMONGST TEMP PLUMES FOR A HANDFUL OF POINTS SUGGESTS THAT LESS MIXING WILL TAKE PLACE TODAY AND TEMPS WILL LIKELY BE IN THE LOW 70S...POSSIBLY MID 70S ALONG AND SOUTH OF A LASALLE TO KANKAKEE LINE. THEN TONIGHT SKIES REMAIN MOSTLY CLEAR WITH A LIGHT SOUTH/SOUTHEAST FLOW AT THE SFC. TEMPS WILL AT FIRST RADIATE INTO THE MID/UPR 50S JUST AFTER SUNSET...THEN SLOWLY COOL THROUGH THE REMAINDER OF THE OVERNIGHT INTO THE MID/UPR 40S. NEAR DOWNTOWN CHICAGO IN THE MID 50S. CONFIDENCE...HIGH. THURSDAY THROUGH SATURDAY... ANOMALOUS MID-LVL TROUGH CONTINUES TO BE PROGGED TO DIG INTO THE FOUR-CORNERS REGION OF THE CONUS EARLY THURSDAY. THIS FEATURE WILL LIKELY FURTHER AMPLIFY THE DOWNSTREAM RIDGE OVER THE GREAT LAKES REGION. ENSEMBLES CONTINUE TO SUGGEST THE RIDGE OVER THE GREAT LAKES WILL DRIFT EAST AND BECOME CENTERED OVER EASTERN ONTARIO/WESTERN QUEBEC THUR...THEN UNDERGO SOME STRENGTHENING. WITH THE WAVE SHOWING SIGNS OF STRENGTHENING FRI INTO SAT VERIFIES...THIS WILL LIKELY DEFLECT THE UPCOMING WEEKEND SHORTWAVE FURTHER NORTHWEST AWAY FROM THE FORECAST AREA. GUIDANCE HAS CONTINUED TO BACK OFF ON PRECIP TIMING AS WELL AS COVERAGE. SFC RIDGING APPEARS TO HOLD ONTO THE REGION THROUGH FRI...AND MID-LVL HEIGHTS ARE STILL SHOWING SOME SIGNS OF RESISTANCE TO THE PROGGED 500MB TROUGH THAT WILL SLIDE EAST FOR THE UPCOMING WEEKEND. AT PRESENT HAVE PUSHED PRECIP OFF UNTIL EARLY SAT MORNING. INSTABILITY DOES NOT LOOK TO BE VERY IMPRESSIVE LATE FRI NIGHT/SAT...WITH PRESENT GUIDANCE INDICATING MUCAPE VALUES STRUGGLING TO REACH 400J/KG. WHILE SOME UNCERTAINTY REMAINS WITH THE UPCOMING SYSTEM...HAVE OPTED TO TRIM BACK MENTION OF THUNDER FROM CHANCE TO SLIGHT CHANCE. TEMPS WILL CONTINUE TO WARM IN ADVANCE OF THE WEEKEND SYSTEM...WITH GUIDANCE TRENDING WELL ABOVE NORMAL WITH HIGHS IN THE MID 70S THUR. GIVEN THE LACK OF CLOUD COVER...AND SOME AFTERNOON MIXING...PARCEL HEAT CAPACITY WILL REMAIN MINIMAL. THIS WILL SUPPORT THE SCENARIO OF AFTN TEMPS FRI WARMING WELL INTO THE 70S...AND CAN NOT RULE OUT AN 80 DEG FOR THE SOUTHERN PORTIONS OF THE CWFA. LLVL MOISTURE WILL ALSO BE ON THE INCREASE LATE WEEK/EARLY WEEKEND...WITH DEW POINTS INCREASING INTO THE MID/UPR 50S. THE ADDED MOISTURE AND INCREASING CLOUDS WILL KEEP OVERNIGHT LOWS FRI NIGHT/EARLY SAT FROM COOLING MUCH...SO HAVE BUMPED TEMPS INTO THE MID/UPR 50S. ABUNDANT CLOUD COVER SAT WILL HELP HOLD TEMPS IN THE LOW/MID 70S...WITH THE EXCEPTION OF THE SOUTHEAST CWFA WHERE TEMPS COULD YET AGAIN WARM INTO THE UPR 70S. IF THE APPROACHING SYSTEM SLOWS OR HAS LESS CLOUD COVER ASSOCIATED...THEN TEMPS SAT WILL WARM INTO THE MID/UPR 70S ACROSS THE CWFA. CONFIDENCE IN TEMPERATURES...HIGH. CONFIDENCE IN PRECIP SAT...MEDIUM. SUNDAY THROUGH TUESDAY... ENSEMBLES CONTINUE TO DEMONSTRATE MINIMAL SPREAD IN THE LONG TERM PERIOD...SUGGESTING INCREASED CONFIDENCE IN THE LONG WAVE PATTERN. THE 3 SIGMA RIDGE OVER ONTARIO/QUEBEC WILL BEGIN TO WEAKEN SUN/MON...WITH THE UPSTREAM TROUGH WEAKENING AND BECOMING SEMI-ZONAL. A LARGE FEATURE THAT IS PROGGED TO DEVELOP IS CONSIDERABLE BLOCKING ACROSS THE NORTH ATLANTIC...WHICH COULD CREATE A BOTTLENECK IN THE PATTERN FOR THE CONUS. CURRENT OPERATIONAL SOLUTIONS CONTINUE TO BE PROGRESSIVE WITH THE EARLY WEEKEND SYSTEM PUSHING THROUGH THE FORECAST AREA SUN MORNING...WHICH SHOULD BRING A RETURN TO SEASONAL TEMPS AND DRY WEATHER FOR MIDDAY SUN THROUGH MON. THE GFS/EC ARE IN DISAGREEMENT EARLY NEXT WEEK...WITH THE GFS REMAINING PROGRESSIVE AND DEVELOPING A ROBUST SHORTWAVE ACROSS THE CENTRAL PLAINS ALONG A QUASI-STATIONARY BOUNDARY. THIS FEATURE IS PROGGED TO REACH THE WESTERN GREAT LAKES LATE MON/TUE. THE EC HAS A SIMILAR SOLUTION...ONLY DEMONSTRATING A SLOWER DEVELOPMENT AND NOT ARRIVING UNTIL TUE/WED. CONFIDENCE...MEDIUM. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... LAKE BREEZE DURING THE AFTERNOON SUPERIMPOSED ON THE SOUTHEAST TO EAST-SOUTHEAST SYNOPTIC SCALE FLOW OVER THE AREA TO BACK WINDS SOMEWHAT LATER TODAY. TRS //DISCUSSION...UPDATED 12Z... LATEST MODEL GUIDANCE MAINTAINS THE SURFACE RIDGE AXIS ALIGNED WESTWARD ACROSS THE LOWER GREAT LAKES AND SOUTHERN LAKE MI. THIS WILL MAINTAIN A WEAK SOUTHEAST TO EAST-SOUTHEAST LOW LEVEL SYNOPTIC FLOW OVER THE LOCAL AREA. WITH LAKE WATER TEMPERATURES IN THE UPPER 50S TO MID 60S AND SURFACE TEMPERATURES EXPECTED TO RISE INTO THE LOWER 70S THIS AFTERNOON THERE LOOKS TO BE ENOUGH TEMPERATURE DIFFERENTAL TO SUPERIMPOSE A WEAK LAKE BREEZE ON TOP OF THE SYNOPTIC FLOW...RESULTING IN WINDS BACKING SOMEWHAT DURING THE AFTERNOON TO EAST-NORTHEAST AT KGYY...EAST AT KMDW...AND EAST-SOUTHEAST AT KORD. VERY DRY AIR MASS ASSOCIATED WITH THE RIDGE FROM SURFACE TO UPPER LEVELS OVER THE REGION CERTAINLY PRECLUDES ANY CLOUDS OF SIGNIFICANCE...AND LITTLE IF ANY AT ALL. //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH ALL ELEMENTS. TRS //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... * THURSDAY NIGHT AND FRIDAY...DRY/VFR. * SATURDAY...CHANCE OF SHRA/TSRA. * SUNDAY...DRY/VFR. * MONDAY AND TUESDAY...SLIGHT CHANCE OF SHRA. && .MARINE... 226 AM...WHILE HIGH PRESSURE IS CENTERED OVER NEW ENGLAND EARLY THIS MORNING...A LARGE WEAKER RIDGE EXTENDS SOUTHWEST ACROSS THE OHIO VALLEY. AS THE CENTER OF THIS HIGH MOVES EAST OVER THE ATLANTIC TODAY AND TONIGHT...THIS RIDGE WILL DRIFT NORTHEAST AND REMAIN ACROSS MUCH OF THE CENTRAL/EASTERN LAKES REGION INTO FRIDAY...WHEN IT WILL BE REINFORCED BY A STRONGER HIGH MOVING SOUTHEAST ACROSS QUEBEC FRIDAY/FRIDAY NIGHT. MEANWHILE... LOW PRESSURE OVER WESTERN ONTARIO WILL CONTINUE TO WEAKEN AS IT MOVES NORTHEAST INTO WESTERN QUEBEC THIS EVENING. HOWEVER...THE GRADIENT WILL REMAIN TIGHT OVER THE NORTHERN HALF OF LAKE MICHIGAN INTO THIS AFTERNOON THEN BEGIN TO WEAKEN SOME TONIGHT. ANOTHER AREA OF LOW PRESSURE OVER COLORADO IS EXPECTED TO MOVE NORTHEAST ACROSS THE PLAINS THURSDAY NIGHT AND FRIDAY REACHING SOUTHERN MANITOBA FRIDAY NIGHT. SOUTHERLY WINDS WILL ONCE AGAIN INCREASE AS THIS SYSTEM MOVES NORTH...BUT THE STRONGEST WINDS SHOULD REMAIN WEST OF LAKE MICHIGAN. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 950 AM CDT Wed Oct 9 2013 .DISCUSSION... ISSUED 950 AM CDT Wed Oct 9 2013 Illinois remaining on the periphery of the high pressure that was centered in New England this morning. Latest satellite imagery showing some stratocumulus spreading northward through southern Illinois. Latest RAP model humidity plot for 925-850 mb shows some of this creeping up to around I-64 this afternoon, but mainly sunny skies will prevail over the CWA. Have sent some updated grids to refresh the hourly temperature and dew point trends, but no changes needed to the zones at this time. Geelhart && .AVIATION... ISSUED 602 AM CDT Wed Oct 9 2013 VFR conditions will continue next 24hrs at all TAF sites. High pressure will continue to hold to our east through the period bringing a mostly clear sky and a light southeast wind. Model forecast soundings and time height cross sections continue to indicate moisture in the 3000-4000 foot level to our southeast will gradually edge north and northwest into our southern TAF areas late tomorrow night. Current indications suggest most if not all the clouds should remain south of our area thru 06z Thursday, but then advance northward enough to affect some of the sites between 09 and 12z. Surface winds will be out of a southeasterly direction at 10 kts or less. Auten && .PREV DISCUSSION... ISSUED 238 AM CDT Wed Oct 9 2013 SHORT TERM...Today through Friday Sprawling high pressure extending from New England to the Southern Plains will dominate the weather across central Illinois over the next couple of days. With ridge axis overhead today, light E/SE winds and slightly lower mixing heights will result in high temps a degree or two cooler than yesterday...with readings generally topping out in the lower to middle 70s. Once the ridge shifts a bit further east and surface winds begin to veer to a more southerly direction, temperatures will slowly increase through the end of the week. High temps on Thursday will be in the middle to upper 70s, while readings on Friday will likely top the 80-degree mark. After sunny skies today, moisture at around 850mb associated with an upper low meandering northward into the Mid-Atlantic states may get drawn into the area on Thursday and Friday. Forecast soundings and CU-rule both suggest increased diurnal cloudiness, yielding partly to mostly sunny skies both days. LONG TERM...Saturday through Tuesday Closed upper low over the Desert Southwest will lift northeastward into the Northern Plains/Upper Midwest over the weekend, pulling a cold front into Illinois. Models still disagree on speed of front, with GFS sticking to its faster solution and the ECMWF lagging about 12 hours behind. Exact speed will depend largely upon strength of Rex blocking that takes place along the East Coast over the next few days as persistent upper low undercuts ridge. Given presence of this feature, prefer the slower ECMWF solution in the extended. As such, will focus highest POPs along/ahead of the approaching front across the western half of the CWA during the day Saturday, then further east across the remainder of the area Saturday night. Will also hold on to low POPs across the E/SE into Sunday as front slowly departs into Indiana. Limited moisture ahead of the boundary and best upper dynamics remaining well to the north support only chance POPs for showers/thunder at this time. Further out, significant timing differences remain among the operational models. Once again, the GFS is much faster with the next approaching system than the ECMWF. Given highly amplified nature of upper trough digging into the Rockies/Plains late in the weekend, would tend to favor the slower ECMWF here as well. Will therefore maintain a warm/dry forecast for Monday before introducing a chance for showers and thunderstorms Monday night into Tuesday. After that, much cooler weather will arrive by the middle of next weeks with temps dropping below normal into the upper 50s/lower 60s by Wednesday. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
151 PM MDT WED OCT 9 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 149 PM MDT WED OCT 9 2013 LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW LARGE SCALE TROUGH ACROSS WESTERN CONUS WITH CLOSED 548DM H5 CENTER OVER WESTCENTRAL CALIFORNIA. 135KT H3 JET IS ROUNDING WESTERN EXTENT OF THIS TROUGH WITH WELL DEFINED PV HEIGHT ANOMALY OVER SOUTHERN CALIFORNIA. SW FLOW AHEAD OF THIS FEATURE IS IN PLACE ACROSS THE PLAINS. AT THE SURFACE A STATIONARY FRONT IS CURRENTLY EXTENDING FORM THE NORTHERN PLAINS ACROSS CENTRAL NEBRASKA TO NEAR KGLD AND WEST TOWARDS NORTHCENTRAL COLORADO. TONIGHT...WITH DRY/STABLE AIR MASS IN PLACE WE SHOULD SEE DRY CONDITIONS CONTINUE THROUGH TONIGHT. FRONT IS PROGGED TO LIFT NORTH THROUGH THE NIGHT WITH SLIGHTLY WARMER AIR MASS BUILDING BACK OVER THE CWA. WHILE H85 TEMPS ARENT TOO DIFFERENT THAN LAST NIGHT...WINDS MAY REMAIN IN THE 10-12KT RANGE WHICH COULD LIMIT RADIATIONAL COOLING. I WENT AHEAD AND BUMPED OVERNIGHT LOWS UP A LITTLE...THOUGH WITH CLEAR SKIES IF WINDS DIMINISH WE COULD END UP WITH LOWS SIMILAR TO LAST NIGHT. THURSDAY...LEE TROUGH DEEPENS THROUGH THE DAY THURSDAY WITH TIGHT PRESSURE GRADIENT DEVELOPING BY THURSDAY AFTERNOON. CONFIDENCE IS HIGH IN WINDY CONDITIONS...HOWEVER THERE ARE SOME MODEL DISCREPANCIES REGARDING WINDS ALOFT...AND THUS PEAK GUST POTENTIAL. BASED ON BL/ML WINDS ON THE NAM I WOULD BE CONFIDENT IN A PERIOD OF ADVISORY LEVEL WINDS (GUSTS 45-50MPH). GFS CONTINUES TO BE THE STRONGER MODEL...WITH HIGH END ADVISORY/NEAR WARNING CRITERIA. THE STRONGEST WINDS APPEAR TO OCCUR AROUND 00Z WHEN MIXING MIGHT NOT BE AS DEEP (CONSIDERING THE EARLIER SUNSET THIS TIME OF YEAR)...SO I WAS NOT CONFIDENT ENOUGH TO ADD A HIGHLIGHT AT THIS TIME. PRECIPITATION CHANCES INCREASE FROM MID AFTERNOON THROUGH 00Z AS LAPSE RATES STEEPEN ALONG SURFACE TROUGH IN EASTERN COLORADO. TD VALUES GENERALLY IN THE 40S WILL LIMIT CAPE TO 500 J/KG OR LESS...AND THUNDERSTORMS WILL BE HIGH BASED (LCL/LFC AROUND 10KFT). AT THE SAME TIME UNIDIRECTIONAL SHEER WILL BE IMPRESSIVE AHEAD OF TROUGH BY LATE AFTERNOON...AND SOUNDINGS ARE INDICATIVE OF STRONG DOWNDRAFT POTENTIAL. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 1246 PM MDT WED OCT 9 2013 STRONG SHORTWAVE TROUGH WILL BRING WIDESPREAD SHOWERS AND THUNDERSTORMS THURSDAY EVENING TO THE AREA. LACK OF MOISTURE/WEAK INSTABILITY CONTINUE TO BE THE LIMITING FACTORS FOR MORE INTENSE CONVECTION. NONETHELESS...HIGH BASED THUNDERSTORMS WILL DEVELOP ALONG THE LEE TROUGH IN EASTERN COLORADO AND MOVE EAST AS A SQUALL LINE IN THE EVENING...WHILE INDIVIDUAL CELLS RACE NORTHEAST AT AROUND 50KTS. DESPITE FAVORABLE SHEAR PROFILES...UPDRAFTS WILL STRUGGLE TO ORGANIZE GIVEN SBCAPE OF LESS THAN 500 J/KG. AS A RESULT...HAIL THREAT SEEMS MINIMAL AND TORNADO THREAT EVEN LESS...HOWEVER DAMAGING WINDS WILL BE LIKELY WITH STRONGEST STORMS GIVEN HIGH BASES AND UNIDIRECTIONAL WINDS THROUGH NEARLY THE ENTIRE TROPOSPHERE. PRECIPITATION WILL END BY 06Z AS SYSTEM QUICKLY LIFTS INTO THE NORTHERN PLAINS. FRIDAY WILL BE COOLER AND DRY...BUT ANOTHER VORT LOBE WILL ROTATE THROUGH THE BASE OF THE LONGWAVE TROUGH FRIDAY NIGHT. HOWEVER...THERE WILL NOT BE ENOUGH TIME FOR MOISTURE RETURN AND THE WEAK LIFT WILL HAVE DIFFICULTY IN GENERATING MORE THAN A FEW ISOLATED TO WIDELY SCATTERED RAIN SHOWERS ACROSS NORTHERN PORTIONS OF THE AREA FRIDAY NIGHT THROUGH SATURDAY MORNING. SHORTWAVE RIDGING WILL BRIEFLY FOLLOW SATURDAY AFTERNOON AND SATURDAY NIGHT...HOWEVER ANOTHER WEAK TROUGH WILL BE MOVING THROUGH THE FLOW ON SUNDAY BRINGING LOW CHANCES OF SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM AS SOME WEAK INSTABILITY IS FORECAST. THE MAIN SYSTEM WILL EJECT ACROSS THE CENTRAL AND NORTHERN ROCKIES MONDAY WITH PRECIPITATION CHANCES CONTINUING AS ASSOCIATED SURFACE COLD FRONT MOVES THROUGH DURING THE DAY ON MONDAY. BREEZY NORTHWEST WINDS WILL FOLLOW FRONTAL PASSAGE MONDAY AFTERNOON AND EVENING AS PRECIPITATION COMES TO AN END. THE REMAINDER OF THE PERIOD (TUESDAY AND WEDNESDAY) WILL SEE DRY NORTHWEST FLOW WITH TEMPERATURES SLIGHTLY BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1117 AM MDT WED OCT 9 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT BOTH KGLD AND KMCK TERMINALS. WINDS GENERALLY AROUND 12KT AT BOTH TERMINALS WILL SHIFT TO THE SOUTHEAST TONIGHT AT KGLD THEN SOUTH AT BOTH TERMINALS BY THURSDAY MORNING AS STATIONARY FRONT LIFTS NORTH. STRONGER WINDS ARE CURRENTLY EXPECTED THURSDAY AFTERNOON OUTSIDE OF THE CURRENT TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...024 AVIATION...DR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
240 PM EDT WED OCT 9 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 239 PM EDT WED OCT 9 2013 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPRAWLING UPR RDG OVER THE E HALF OF THE CONUS DOWNWIND OF TROF OVER THE W. AT THE SFC...HI PRES IS SITUATED OVER NEW ENGLAND...WITH WEAKENING LO PRES OVER NW ONTARIO ASSOCIATED WITH CNDN SHRTWV RIDING OVER UPR RDG. THE CWA IS DOMINATED BY THE LLVL SW FLOW BTWN THESE FEATURES. BUT BECAUSE THE SFC LO IS WEAKENING WITH PRES RISES OBSVD OVER THE SFC LO...THE GRADIENT IS WEAKENING STEADILY WITH TIME. SO SW WINDS THIS AFTN ARE NOT AS GUSTY AS YDAY DESPITE DAYTIME HEATING/MIXING. OTRW...THE LOCAL AND UPSTREAM 12Z RAOBS SHOW A RELATIVELY DRY LLVL AIRMASS...SO THERE IS NOTHING MORE THAN PATCHY HI CLDS TO THE SW OF SOME THICKER CLDS IN ONTARIO ASSOCIATED WITH THE LO WELL N OF THE BORDER. THE ONLY EXCEPTION WAS A BIT OF LO CLD THAT DVLPD DOWNWIND OF LK MI NEAR MANISTIQUE WHERE THE SW FLOW OFF THE WATER HAS LIFTED SFC DEWPTS AS HI AS 55 TO 60. WITH A RIBBON OF H85 TEMPS UP TO 15C STREAMING INTO THE WRN CWA IN THE SW FLOW...TEMPS ARE RUNNING WELL ABV NORMAL EARLY THIS AFTN WITH READINGS AS HI AS THE LO 70S AT SOME PLACES AWAY FM THE MODERATING INFLUENCE OF LK MI. MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON TEMPS WITH DRY...ACYC SW FLOW ARND SFC HI PRES STRETCHING FM THE NE COAST INTO THE GREAT LKS FCST TO DOMINATE THRU THU. TNGT...EXPECT LO TEMPS TNGT TO FALL A BIT MORE THAN LAST NGT WITH DRY AIR LINGERING UNDER WEAKENING PRES GRADIENT/SW FLOW AS HIER PRES SLOWLY EXPANDS TO THE W. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR SCENTRAL AND E...CLOSER TO THE WEAKEST GRADIENT/LOWER PWATS AOB 0.5 INCH. WITH THESE IMPROVED RADIATIONAL COOLING CONDITIONS OVER HIER DEWPTS OBSVD THIS AFTN...EXPECT PATCHY FOG IN THESE AREAS. THU...LOOKS LIKE ANOTHER PLEASANT OCT DAY WITH DRY SW FLOW FCST TO DOMINATE AND LEAD TO MOSUNNY CONDITIONS. H85 TEMPS ARE FCST NEAR 14C...ALMOST THE SAME AS TDAY...SO EXPECT MAX TEMPS TO BE SIMILAR TO THIS AFTN. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 239 PM EDT WED OCT 9 2013 AT 00Z FRI...THERE WILL BE AN UPPER RIDGE OVER THE CWA THAT WILL GIVE WAY TO A LOW PRESSURE SYSTEM MOVING FROM NE AT 12Z FRI TO FAR SRN MANITOBA AT 12Z SAT. FRI WILL BE QUIET WITH NO PRECIP EXPECTED DUE TO THE RIDGE BEING OVERHEAD...BUT WITH 850MB TEMPS AROUND 14C...TEMPS WILL BE WELL ABOVE NORMAL WITH HIGHS IN THE 60S AND 70S. AFTER 12Z SAT...MODEL DISAGREEMENT ON THE TIMING/TRACK OF THE SYSTEM IS MORE UNCERTAIN. THE 12Z/09 GFS KEEPS THE LOW MOVING RAPIDLY NNE TO HUDSON BAY BY 00Z SUN...WHILE 00Z/09 ECMWF HANGS THE LOW OVER ONTARIO WHILE WEAKENING...AND FINALLY MOVING TO JAMES BAY AROUND 06Z MON. THE 00Z/09 GEM SOLUTION IS BETWEEN THE GFS AND ECMWF WITH TIMING/TRACK. PRECIP OVER THE CWA FROM THIS SYSTEM WILL MAINLY RESULT FROM THE ASSOCIATED COLD FRONT MOVING THROUGH. OF COURSE...THERE ARE ALSO SOME TIMING DIFFERENCES WITH TIMING OF FROPA. THE GFS MOVES THE FRONT FROM THE WRN U.P. AT 18Z SAT TO THE ERN CWA AROUND 06Z SUN...WITH THE ECMWF BEING AROUND 6 HOURS SLOWER. THE GEM MATCHES UP PRETTY CLOSE TO THE GFS WITH FROPA TIMING. THERE MAY BE SOME SHOWERS OVER THE WRN CWA FRI NIGHT AS THE LOW MOVES TO THE W...BUT OTHERWISE MOST PRECIP WITH THE FRONT SHOULD BE OVER THE CENTRAL AND ERN CWA WHERE THE FRONT WILL INTERACT WITH BETTER INSTABILITY AND MAY BE BACKED UP BY AN UPPER SHORTWAVE TROUGH. WILL NOT GO COMPLETELY DRY OVER THE W...BUT WILL HAVE HIGHEST POPS CENTRAL AND E AND TIMING CLOSER THE GFS/GEM SOLUTIONS. COLDER AIR WILL FILTER IN BEHIND THE SYSTEM...WITH 850MB TEMPS FALLING INTO THE LOW SINGLE DIGITS ABOVE AND MAYBE JUST BELOW ZERO BY LATE SUN/SUN NIGHT. THIS IS WHERE THE MODEL DIFFERENCES BECOME MORE SIGNIFICANT AS THE GFS AND GEM USHER IN DRY HIGH PRESSURE FOR SUN NIGHT WHILE THE ECMWF SOLUTION WITH THE LAGGING LOW WILL KEEP MORE CLOUDS OVERHEAD. WITH THE CLOUDIER ECMWF SOLUTION...LOW TEMPS SUN NIGHT SHOULD FALL INTO THE UPPER 30S TO MID 40S. THE LESS CLOUDY SOLUTIONS WOULD LIKELY RESULT IN A DECENT FREEZE AWAY FROM THE IMMEDIATE SHORES OF THE GREAT LAKES. WILL GO WITH A MIDDLE OF THE ROAD APPROACH AND KEEP CONSENSUS LOW TEMPS FROM THE MID 30S TO MID 40S. THINGS BECOME MORE UNCERTAIN MON THROUGH NEXT WED AS MODELS CONTINUE TO POINT TO A MAJOR PATTERN CHANGE FROM THIS PORTION OF THE COUNTRY. MODELS GENERALLY SHOW MUCH INCREASED UPPER TROUGHING OVER THE ERN HAVE OF THE CONUS...RESULTING IN COLDER TEMPERATURES AND GREATER STRENGTH/FREQUENCY OF SYSTEMS MOVING THROUGH THE REGION. DEFINITELY LOOKS COLDER WITH TEMPS EVEN FALLING TO BELOW NORMAL VALUES. POPS ARE FAR MORE UNCERTAIN AS SYSTEM STRENGTH/TRACK IS FAR FROM CERTAIN. TEMPS DO NOT LOOK QUITE COLD ENOUGH TO ADD MIXED PRECIP TO THE FORECAST...ESPECIALLY GIVEN UNCERTAINTY INVOLVED. USED A CONSENSUS OF MODEL GUIDANCE FOR THIS PORTION OF THE FORECAST PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 120 PM EDT WED OCT 9 2013 EXPECT GUSTY S-SW WINDS THIS AFTN TO DIMINISH TOWARD SUNSET WITH LOSS OF DAYTIME HEATING/MIXING AND WEAKENING PRES GRADIENT. WINDS ON THU SHOULD NOT BE AS GUSTY AS TODAY WITH THE WEAKER GRADIENT STILL IN PLACE. OTRW...DRY HI PRES WL BRING VFR WX TO THE TAF SITES THIS FCST PERIOD. THE ONE EXCEPTION MAY BE SAW LATE TNGT/EARLY THU...WHERE SOME FOG COULD FORM. WITH THE LLVL FLOW MORE SSW VS SSE OFF LK MI...OPTED TO KEEP THIS SITE VFR ATTM. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 239 PM EDT WED OCT 9 2013 EXPECT S TO SW WINDS UP TO 20 KTS THRU THU NIGHT TO INCREASE TO UP TO 25 KTS ON FRI INTO SAT AS THE PRES GRADIENT TIGHTENS BETWEEN HI PRES OVER THE EASTERN CONUS AND AN APPROACHING COLD FRONT. BEHIND THIS FRONTAL PASSAGE ON SAT...LOOK FOR A WIND SHIFT TO THE W-NW BEFORE WINDS SLOWLY VEER TO THE N BY MON AHEAD OF AN APPROACHING HI PRES CENTER. WINDS WILL BE AS HI AS 20-25 KTS ON SAT NIGHT/SUN FOLLOWING THIS FROPA...BUT THESE WINDS SHOULD DIMINISH UNDER 20 KTS BY MON AS THE HI PRES/WEAKER PRES GRADIENT MOVES NEARBY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...TITUS AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1229 PM CDT WED OCT 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 225 AM CDT WED OCT 9 2013 MAIN SHORT TERM FORECAST CONCERNS ARE ON WINDS AND TEMPERATURES TODAY. CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEPENING TROUGHING OVER THE WESTERN U.S. AND STRENGTHENING RIDGING FROM LOUISIANA INTO THE GREAT LAKES. THE SOUTHWEST FLOW BETWEEN THESE FEATURES HAS BEEN BRINGING A VARIETY OF WEAK SHORTWAVES TOWARDS THE FORECAST AREA. HOWEVER...DUE TO PLENTIFUL DRY AIR IN THE LOW TO MID LEVELS OF THE TROPOSPHERE AS EVIDENCED ON 00Z SOUNDINGS FROM DDC TO OAX AND MPX...THE SHORTWAVES HAVE BEEN ONLY ABLE TO PRODUCE SCT-BKN CIRRUS CLOUDS. OF SOMEWHAT MORE SIGNIFICANCE IS THE STRENGTH OF THE LOW LEVEL SOUTHWEST FLOW. AHEAD OF A COLD FRONT DRAPED FROM NORTHWEST MN INTO WESTERN NEBRASKA PER SURFACE ANALYSIS...35-50 KT SOUTHWEST 850MB WINDS WERE PRESENT FROM WESTERN KANSAS THROUGH THE FORECAST AREA AND INTO UPPER MICHIGAN. SOME OF THIS BREEZE EXTENDS DOWN THE SURFACE...HELPING TO KEEP TEMPERATURES WELL ABOVE NORMAL DESPITE SURFACE DEWPOINTS IN THE MID 40S. OVER THE NEXT 24 HOURS...MODELS ARE IN GOOD AGREEMENT OF THE WESTERN TROUGH DIGGING DEEPER...FEATURING AN UPPER LOW IN THE VICINITY OF LAS VEGAS BY 12Z THURSDAY. MEANWHILE...THE UPPER RIDGE DOWNSTREAM STRENGTHENS FURTHER TO HELP BALANCE THE DEEPER WESTERN TROUGH... RESULTING IN A BLOCKED UP PATTERN. THUS...THAT FRONTAL BOUNDARY FROM NORTHWEST MN INTO WESTERN NEBRASKA GOES NOWHERE AND THE FORECAST AREA STAYS IN DRY LOW TO MID LEVEL SOUTHWEST FLOW. THE PRESSURE GRADIENT MAGNITUDE...A MEASURE OF HOW TIGHT THE PRESSURE GRADIENT IS...MODELS PROG TO BE 40-50 PERCENT LESS THAN YESTERDAY. SO ALTHOUGH MIXING AND MAINTAINING A DECENT PRESSURE GRADIENT STILL SUGGESTS BREEZY CONDITIONS...ESPECIALLY WEST OF THE MISSISSIPPI RIVER...EXPECT WINDS TO NOT BE AS GUSTY AS YESTERDAY. 925MB TEMPERATURES TODAY ARE FORECAST ABOUT 2C COOLER COMPARED TO YESTERDAY...RANGING FROM 14-16C VERSUS THE 17-20C OBSERVED FROM 00Z SOUNDINGS. IT APPEARS THE REASON FOR THE COOLER CONDITIONS IS THE LOW LEVEL FLOW BACKING MORE SOUTHERLY. THEREFORE...HIGHS ARE LIKELY TO BE A FEW DEGREES COOLER. A SOUTHERLY BREEZE LOOKS TO PERSIST TONIGHT...BUT NOT AS STRONG AS THIS MORNING. THIS MEANS THE TYPICAL COLD SPOTS IN WISCONSIN STAND A MUCH BETTER CHANCE OF DECOUPLING AND DROPPING CLOSER TO THE DRIER DEWPOINTS IN PLACE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 225 AM CDT WED OCT 9 2013 MAIN LONG TERM FORECAST CONCERNS ARE ON WINDS FRIDAY AND POTENTIAL FOR PRECIPITATION FRIDAY THROUGH SATURDAY. SYNOPTIC OVERVIEW... MUCH OF THE FOCUS ON THE FORECAST REMAINS ON THE EVOLUTION OF THE WESTERN TROUGH...AND IN PARTICULAR THE UPPER LOW NEAR LAS VEGAS AT 12Z THURSDAY. GOOD MODEL AGREEMENT EXISTS THAT THE UPPER LOW WILL GET EJECTED OUT AND SHUNTED NORTH THROUGH THE DAKOTAS ON FRIDAY. FROM THERE INDICATIONS ARE THAT PHASING OCCURS WITH A SHORTWAVE TROUGH COMING THROUGH THE NORTHERN STREAM ACROSS SOUTH CENTRAL CANADA...RESULTING IN A FAIRLY DEEP LOW PRESSURE SYSTEM IN MANITOBA COME SATURDAY. THIS SYSTEM LIFTS OUT ON SUNDAY WHILE NEW TROUGHING RELOADS OVER THE WESTERN U.S.. THERE ARE PLENTY OF DISAGREEMENTS AMONGST THE MODEL HANDLING OF THIS NEW WESTERN TROUGH...PRIMARILY ITS PROGRESSION EAST WHERE THE 09.00Z GFS IS MUCH FASTER THAN THE 09.00Z CANADIAN/ECMWF AND 09.00Z CANADIAN ENSEMBLES. DETAILS... THURSDAY AND THURSDAY NIGHT WILL REMAIN DRY WITH THE BLOCKED UP PATTERN AHEAD OF THE WESTERN TROUGH. WINDS LOOK TO GRADUALLY INCREASE OUT OF THE SOUTH/SOUTHEAST AS WELL...IN RESPONSE TO DYNAMICAL FORCING DOWNSTREAM OF THE UPPER LOW EJECTING OUT CAUSING PRESSURES TO LOWER OVER THE PLAINS. 925MB TEMPS CLIMB ABOUT 1C FROM TODAY...RESULTING IN A SLIGHTLY WARMER DAY. MORE WIND AT NIGHT...ESPECIALLY ABOVE THE SURFACE...SHOULD HELP TO PRODUCE A WARMER NIGHT AS WELL. FRIDAY REMAINS A DAY TO FOCUS ON WINDS. AS THE UPPER AND SURFACE LOWS LIFT THROUGH THE DAKOTAS ON FRIDAY...THE PRESSURE GRADIENT TIGHTENS FURTHER OVER THE FORECAST AREA. THE MAGNITUDE OF THE GRADIENT IS ON PAR WITH THAT SEEN YESTERDAY...EXCEPT ALL OF THE FORECAST AREA SEES THE STRONGER GRADIENT VERSUS JUST WEST OF THE MISSISSIPPI RIVER. THUS A WINDY DAY IS LIKELY EVERYWHERE... ESPECIALLY IN HIGHER TERRAIN EXPOSED LOCATIONS. MIXING ON FORECAST SOUNDINGS FROM THE 09.00Z GFS/NAM SUGGEST WIND ADVISORY CRITERIA COULD BE REACHED IN THOSE LOCATIONS...SUCH AS DODGE CENTER AND ROCHESTER MN. THE WINDS ALSO HELP DRIVE UP 925MB TEMPS TO 16-18C...SUPPORTING HIGHS AS MUCH AS THE MID TO UPPER 70S DEPENDING ON AMOUNT OF SUNSHINE. LATE FRIDAY THROUGH SATURDAY FOCUS SWITCHES TO PRECIPITATION POTENTIAL. SOUTHERLY FLOW AHEAD OF THE UPPER AND SURFACE LOWS HEADING UP INTO MANITOBA HELPS TO DRAW HIGHER PRECIPITABLE WATER VALUES INTO THE FORECAST AREA. VALUES ARE PROGGED TO REACH 1-1.2 INCHES BY 00Z SATURDAY VERSUS THE 0.3-0.6 INCHES PRIOR TO THEN. THOSE VALUES ARE ACTUALLY 150-200 PERCENT OF NORMAL. THE QUESTION IS IF FORCING EXISTS TO ACT ON THE MOISTURE TO SQUEEZE OUT SOME RAIN. THE TRACK OF THE UPPER LOW IS UNDESIRABLE...KEEPING THE DPVA FORCING FROM IT NORTHWEST OF THE AREA. A SMALL PORTION OF THE WARM CONVEYOR BELT AHEAD OF THE UPPER LOW MAY BRUSH WESTERN PORTIONS OF THE FORECAST AREA LATE FRIDAY WITH SOME LIGHT RAIN SHOWERS OR SPRINKLES...BUT THIS IS A LOW CHANCE. FRIDAY NIGHT MAY STAND TO HAVE THE GREATEST CHANCE OF RAIN...IF THE 09.00Z CANADIAN MODEL FORECAST IS CORRECT. THE MODEL BRINGS UP A STRONGER SHORTWAVE THAN INDICATED BY ALL OTHER MODELS THROUGH THE SOUTHWEST FLOW INTO IOWA BY 12Z SATURDAY. THIS SHORTWAVE HELPS TIGHTEN UP THE FRONTOGENESIS AROUND A COLD FRONTAL BOUNDARY MAKING ITS WAY THROUGH THE FORECAST AREA... LEADING TO A BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS. MEANWHILE...THE 09.00Z GFS/NAM POINT TO A DRY OR MOSTLY DRY SCENARIO. FOR NOW HAVE MAINTAINED 20 PERCENT CHANCES OF SHOWERS AND THUNDERSTORMS BUT WOULD NOT BE SURPRISED TO HAVE TO CHANGE TO A DRY FORECAST. SATURDAY IS STILL UP IN THE AIR...WITH THE 09.00Z GFS/CANADIAN AND 08.12Z ECMWF TRENDING DRIER...SUGGESTING ANY ADDITIONAL FRONTOGENETIC OR INSTABILITY FORCING ALONG THE COLD FRONT OCCURS MOSTLY EAST OF THE FORECAST AREA. HOWEVER...THE 09.00Z ECMWF CAME BACK SHOWING THIS FORCING OCCURRING FARTHER WEST...ENCOMPASSING THE SOUTHEAST HALF OF THE AREA IN PRECIPITATION. THUS CHANCES OF PRECIPITATION NEED TO REMAIN IN THE FORECAST FOR SATURDAY. LOOKING FARTHER AHEAD...THE ONLY FEATURE OF NOTE WILL BE A LOW PRESSURE SYSTEM THAT DEVELOPS OVER THE PLAINS SUNDAY INTO MONDAY... ASSOCIATED WITH THE NEW WESTERN TROUGH. MUCH UNCERTAINTY EXISTS ON WHEN THE SYSTEM EVENTUALLY IMPACTS THE REGION...THEREFORE...HAVE FOLLOWED A MODEL CONSENSUS FOR TEMPERATURES AND PRECIPITATION CHANCES. IT DOES APPEAR RIGHT NOW THAT THE FORECAST AREA WILL LIE ON THE NORTH/COOL SIDE OF THE SYSTEM...WHICH WOULD SUGGEST A GREATER CHANCE OF SEEING RAIN. FOR WHAT ITS WORTH...THE 09.00Z GFS REALLY DEEPENS THE SYSTEM ENOUGH TO ALLOW FOR A RAIN/SNOW MIX...BUT THIS SOLUTION IS VERY HARD TO TRUST GIVEN THE MODEL UNCERTAINTY. && .AVIATION...THROUGH 18Z THURSDAY 1229 PM CDT WED OCT 9 2013 MAIN AVIATION CONCERNS THROUGH TAF PERIOD ARE SOUTHERLY WIND SPEEDS AND GUSTS AT BOTH RST AND LSE TAF SITES. GRADIENT BETWEEN HIGH PRESSURE OVER SOUTHERN MICHIGAN AND WEAK COLD FRONT OVER WESTERN MINNESOTA AND EASTERN SOUTH DAKOTA WILL ALLOW WIND SPEEDS TO BE SUSTAINED BETWEEN 12 TO 15 KNOTS AT BOTH TAF SITES AND POTENTIALLY GUST UP TO 25 KNOTS AT RST THIS AFTERNOON. GRADIENT SLACKENS THIS EVENING AND POTENTIALLY ALLOWS FOR THE DEVELOPMENT OF FOG TO FORM IN RIVER VALLEYS. HOWEVER...WINDS ALOFT ARE NOT VERY FAVORABLE FOR WIDESPREAD FOG TO DEVELOP AND THIS WILL KEEP NEAR SURFACE BOUNDARY LAYER MIX AFTER 06Z THURSDAY. WILL CONTINUE MENTION OF PATCHY FOG AT LSE TAF SITE BETWEEN 10-14Z. GRADIENT THEN TIGHTENS ACROSS THE AREA...AS FRONT SLOWLY MOVES INTO WESTERN MINNESOTA. EXPECT SOUTHERLY WINDS TO INCREASE AFTER 14Z THURSDAY AT BOTH TAF SITES. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...DTJ