399
FXUS62 KGSP 241511
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1011 AM EST MON FEB 24 2020
SYNOPSIS
A VIGOROUS LOW PRESSURE SYSTEM WILL MOVE FROM THE PLAINS TODAY TO
THE OHIO RIVER VALLEY ON TUESDAY SPREADING MOISTURE BACK ACROSS THE
SOUTHEAST. CONDITIONS WILL REMAIN UNSETTLED THROUGH THE MIDDLE OF
THE WEEK. EXPECT BREEZY CONDITIONS WEDNESDAY INTO THURSDAY WITH
BELOW NORMAL TEMPERATURES THROUGH THE END OF THE WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 1000 AM: STILL A FEW FLAKES OF SNOW FALLING IN THE HIGHEST
ELEVATIONS, BUT WITH LITTLE TO NO ACCUM SEEN ON WEBCAMS. OTHERWISE,
AREA RADARS SHOWING RELATIVELY WEAK ECHOES/VERY LIGHT RAIN THIS
MORNING. DEEPER MOISTURE AND STRONGER UPPER DIVERGENCE WILL
MOVE INTO THE AREA THIS AFTN, RESULTING IN MORE WIDESPREAD
LIGHT-TO-MODERATE RAIN. MEANWHILE, TEMPS ARE GENERALLY STILL
FALLING, AS AN IN-SITU WEDGE DEVELOPS. ALL OF THIS TO SAY THAT
THE FCST LOOKS TO BE IN GOOD SHAPE.
OTHERWISE, A COMPLEX LOW PRESSURE AND FRONTAL SYSTEM WILL MOVE OUT
OF THE PLAINS INTO THE MS RIVER VALLEY TODAY. DEEP MOISTURE AND
FORCING AHEAD OF THIS SYSTEM WILL MOVE INTO OUR AREA TODAY. SPOTTY
RAIN WILL MOVE ACROSS THE AREA THIS MORNING. PRECIP BECOMES
WIDESPREAD THIS AFTERNOON AS ISENTROPIC LIFT AND DEEP LAYER FORCING
DEVELOPS. WEAK HIGH PRESSURE REMAINING OVER THE AREA WILL HELP A
WEAK IN-SITU WEDGE DEVELOP AS PRECIP MOVES OVER THE AREA. PRECIP
RATES WILL PICK UP WEST OF THE I-26 CORRIDOR WHERE THE BETTER
FORCING MOVES IN DURING THE AFTERNOON. HOWEVER, CONVECTION IS NOT
EXPECTED AS THE WEDGE KEEPS THE ATMOSPHERE STABLE. THE PRECIP
AND DEVELOPING WEDGE WILL HELP KEEP HIGHS TO AROUND 10 DEGREES
BELOW NORMAL.
WIDESPREAD RAIN CONTINUES ACROSS THE AREA THROUGH THE EVENING THEN
BEGINS TO TAPER OFF FROM WEST TO EAST OVERNIGHT. EVEN WITH THE WEDGE
IN PLACE AND LITTLE CHANCE OF CONVECTION, PRECIP RATES INCREASE
DRAMATICALLY AS A WAVE OF LOW PRESSURE MOVES EAST ALONG THE WEDGE
BOUNDARY. RAINFALL AMOUNTS OF 1 TO 2 INCHES WILL BE COMMON ACROSS
THE AREA. WHILE NO WIDESPREAD FLOODING IS EXPECTED DUE TO THE RECENT
DRYING, ISOLATED FLOODING COULD DEVELOP IN AREAS WHERE RAINFALL
RATES ARE HIGHER OR UPSLOPE FLOW CAN INCREASE AMOUNTS. LOWS WILL
LIKELY BE EARLY IN THE EVENING WITH TEMPS SLOWLY WARMING OVERNIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 325 AM MONDAY: THE SHORT-TERM FCST PICKS UP AT 12Z ON
TUESDAY WITH VERY BROAD AND DEEP UPPER TROFING DIGGING DOWN
OVER THE SOUTHERN ROCKIES WHILE UPPER RIDGING REMAINS ANCHORED
TO OUR SOUTHEAST. OVER THE NEXT 48 HRS, THE TROF WILL STEADILY
APPROACH OUR AREA. THE TROF AXIS IS EXPECTED TO LIFT UP AND
OVER THE CWFA BY THE END OF THE PERIOD EARLY THURSDAY. AT THE
SFC, LOW PRESSURE WILL BE PASSING JUST TO OUR NW EARLY TUESDAY
AS ITS ASSOCIATED COLD FRONT MOVES EAST OF THE FCST AREA AND
DRIER AIR SPREADS OVER THE CWFA. ON WED, THE ABOVE MENTIONED
LOW DEEPENS AS IT SLOWLY LIFTS FARTHER NORTH AND AS IT DOES,
IT GENERATES ANOTHER COLD FRONT. THIS FRONT IS EXPECTED TO MOVE
THRU THE CWFA BY LATE WED, AND THEN OFFSHORE EARLY THURS AS
THE PERIOD ENDS. ABOVE NORMAL TEMPS WILL PREVAIL EARLY IN THE
PERIOD, BUT WILL FALL BACK BELOW NORMAL BEHIND THE FRONT AS
SKIES CLEAR. UPSLOPE FORCING WITHIN THE COLDER AIRMASS WILL
ALLOW POPS TO LINGER NEAR THE NC/TENN BORDER INTO EARLY THURS.
FALLING TEMPS SHOULD PERMIT A CHANGE TO SNOW, ALTHOUGH THE
MOISTURE IS RELATIVELY SHALLOW AND IS NOT EXPECTED TO PRODUCE
ADVISORY-LEVEL ACCUMULATIONS.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 255 AM MONDAY: THE EXTENDED FCST PICKS UP AT 12Z ON THURSDAY
WITH VERY BROAD UPPER TROFING OVER MUCH OF THE EASTERN AND CENTRAL
CONUS AND UPPER RIDGING OVER THE FAR WEST. THE LONG-RANGE GUIDANCE
HAS THE TROF AXIS LIFTING TO OUR NE AS THE PERIOD BEGINS EARLY THURS,
WITH A REINFORCING TROF AXIS DROPPING DOWN THE BACKSIDE OF THE BROADER
TROF EARLY FRIDAY. THE TROF WILL REMAIN OVER THE REGION WELL INTO
WEEKEND AND LIKELY AMPLIFY AS IT DRIFTS EASTWARD. AS THE PERIOD ENDS
EARLY NEXT MONDAY, THE HEIGHTS WILL FINALLY BE RECOVERING AS UPPER
RIDGING SPREADS OVER THE REGION. AT THE SFC, COOLER AND DRIER HIGH
PRESSURE WILL BE SPREADING OVER THE FCST AREA AS THE PERIOD BEGINS.
BY EARLY FRIDAY, A WEAK SECONDARY COLD FRONT MOVES THRU THE FCST
AREA FROM THE WEST. THE MODELS DEPICT SOME BRIEF DEEPER MOISTURE
ASSOCIATED WITH THIS FEATURE, BUT IT IS PRETTY TRANSITORY AND APPEARS
TO MOVE EAST OF THE CWFA BY EARLY SAT. SOME OF THE GUIDANCE DOES
MAINTAIN SHALLOW MOISTURE AND NWLY FLOW OVER THE NC/TENN BORDER
REGION THRU MUCH OF SAT, HOWEVER MODEL CONSISTENCY REMAINS MEDIOCRE
AT THIS TIME. THE REST OF THE PERIOD APPEARS TO BE DRY AS REINFORCING
HIGH PRESSURE SPREADS BACK OVER THE REGION.
AVIATION /15Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: SPOTTY LIGHT RAIN EARLY THIS MORNING AS CIGS
FALL TO LOW VFR EARLY. CIGS FALL TO MVFR BY LATE MORNING WITH SLOWLY
LOWERING VSBY AS PRECIP BECOMES WIDESPREAD. IFR CIGS AND VSBY
DEVELOP DURING THE AFTERNOON AS PRECIP SLOWLY BECOMES HEAVIER. LIFR
CIGS EXPECTED TO DEVELOP DURING THE EVENING AND CONTINUE OVERNIGHT.
VSBY DROPS TO MVFR BY AFTERNOON AS PRECIP RATES SLOWLY INCREASE.
VSBY DROPS TO IFR BY LATE AFTERNOON AND CONTINUES THROUGH THE NIGHT
AS MODERATE TO HEAVY PRECIP CONTINUES. LIFR VSBY POSSIBLE IN HEAVIER
SHOWERS. LIGHT S TO SW WIND THIS MORNING BECOMING E TO NE LATE IN
THE DAY THROUGH THE NIGHT FOR ALL BUT KCLT WHERE THEY GO SE. KAVL
WILL SEE SSE WIND THOUGHOUT. VSBY IMPROVES AFTER DAYBREAK TUESDAY AS
PRECIP TAPERS OFF. LIFR CIGS CONTINUE THROUGH THE MORNING.
OUTLOOK: IMPROVING CONDS ARE EXPECTED TUESDAY AFTERNOON, AS PRECIP
EXITS TO THE EAST. VFR CONDITIONS SHOULD RETURN ON WEDNESDAY AND
PERSIST THRU THE END OF THE WORK WEEK.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-12Z
KCLT HIGH 100% MED 71% HIGH 86% HIGH 90%
KGSP HIGH 95% HIGH 83% HIGH 90% MED 70%
KAVL HIGH 88% HIGH 81% HIGH 95% HIGH 86%
KHKY HIGH 98% HIGH 81% HIGH 93% HIGH 90%
KGMU HIGH 89% HIGH 83% MED 62% MED 65%
KAND MED 65% HIGH 85% HIGH 85% HIGH 94%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES ARE AVAILABLE AT
THE FOLLOWING LINK:
WWW.WEATHER.GOV/GSP/AVIATION
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...JPT
NEAR TERM...ARK/RWH
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...RWH
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