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.
&&
$$
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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