424
FXUS62 KGSP 181841
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
241 PM EDT WED SEP 18 2019
SYNOPSIS
COOL SURFACE HIGH PRESSURE WILL STEADILY BUILD OVER THE AREA
THROUGH THURSDAY AND THEN LINGER WELL INTO THE WEEKEND. THIS
WILL ALLOW TEMPERATURES TO GRADUALLY WARM AGAIN THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH THURSDAY/
AS OF 230 PM EDT WEDNESDAY: DRY HIGH PRESSURE WILL CONTINUE TO WEDGE
EAST OF THE APPALACHIANS THROUGH THURSDAY, SUPPORTING CONTINUED FALL-
LIKE AND NEAR TO BELOW NORMAL TEMPERATURES. THIS WILL SUPPORT LIGHT
EAST TO NORTHEAST WINDS WITH LOW CLOUDS AT TIMES, ESPECIALLY THROUGH
MID MORNING THURSDAY. TEMPERATURES GENERALLY IN THE 70S THIS
AFTERNOON WILL DROP DOWN TO THE 50S NEAR 60 TONIGHT, COOLEST ACROSS
THE NC PIEDMONT AND HIGHER ELEVATIONS. HIGHS WILL ONLY REBOUND INTO
THE 70S ONCE AGAIN ON THURSDAY DESPITE GRADUALLY CLEARING SKIES.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
AS OF 2:35 PM EDT WEDNESDAY: THE SHORT-TERM FCST PICKS UP AT 00Z
ON FRIDAY WITH STEEP UPPER RIDGING STILL IN PLACE OVER THE REGION
AS THE UPPER LOW ASSOCIATED WITH TC HUMBERTO MOVES FARTHER OFF THE
ATLANTIC COAST. UPPER RIDGING WILL REMAIN FIRMLY IN PLACE THRU THE
SHORT-TERM PERIOD AND INTO THE EXTENDED PERIOD. AT THE SFC, HIGH
PRESSURE FROM EASTERN CANADA WILL BE MOVING SOUTHWARD AND OVER THE
MID-ATLANTIC STATES BY THE START OF THE PERIOD. AS WE MOVE INTO
SATURDAY, THE CENTER OF THE HIGH WILL SLIDE OVER THE EASTERN CAROLINAS
AND THEN BEGIN TO SLOWLY DRIFT EASTWARD AS THE PERIOD ENDS. THIS
PATTERN WILL KEEP THINGS DRY OVER OUR AREA THRU THE PERIOD WITH
TEMPERATURES STEADILY WARMING THRU THE PERIOD.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
AS OF 2:25 PM EDT WEDNESDAY: THE EXTENDED FCST PICKS UP AT 00Z
ON SUNDAY WITH BROAD UPPER RIDGING DEAMPLIFYING, YET STILL OVER
THE SOUTHEAST. AS WE MOVE INTO EARLY NEXT WEEK, HEIGHTS WILL
STEADILY FALL AS BROAD UPPER TROFING DIGS DOWN ACROSS THE GREAT
LAKES AND TO OUR NORTH. AT THE SFC, ROBUST HIGH PRESSURE WILL
BE CENTERED JUST TO OUR EAST BY LATE SAT/EARLY SUN, WITH WARM
AND DRY SLY FLOW OVER THE AREA. OVER THE NEXT 24 TO 48 HRS,
THE HIGH WILL DRIFT OFFSHORE AS A COLD FRONT APPROACHES THE
CWFA FROM THE NORTH. THE LONG-RANGE MODELS VARY WRT WHEN THE
FRONT WILL MOVE THRU THE FCST AREA, BUT GENERALLY AGREE THAT
IT WILL WEAKEN TO SOME DEGREE AS IT APPROACHES FROM THE NW AND
WILL PASS THRU BY LATE TUES. MOST OF THE CURRENT GUIDANCE DOES
AGREE THAT IT SHOULD BE A MOSTLY DRY FROPA. IN THE FRONT'S
WAKE, REINFORCING HIGH PRESSURE IS EXPECTED TO MOVE BACK OVER
THE AREA AND LINGER FOR THE REMAINDER OF THE PERIOD. THE PERIOD
SHOULD BE DRY, EXCEPT FOR SOME SLIGHT CHANCE POPS OVER THE HIGHER
TERRAIN AS THE FRONT MOVES OVER THE AREA. TEMPS WILL STEADILY
CLIMB THRU THE PERIOD, REACHING 90 DEGREES AT SOME LOCATIONS BY
EARLY NEXT WEEK.
AVIATION /19Z WEDNESDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: A WEDGE OF HIGH PRESSURE ACROSS THE REGION
WILL SUPPORT LIGHT E/NE WINDS (S/SE KAVL) WITH VFR CIGS PREVAILING.
BRIEF MVFR CIGS ARE POSSIBLE BETWEEN 08Z AND 16Z WITH A 30 PERCENT
CHANCE OF BRIEF IFR CIGS AT KAVL DURING THIS TIME.
OUTLOOK: PATCHY MOUNTAIN FOG WILL GRADUALLY RETURN HEADING INTO THIS
WEEKEND WITH VFR CONDS PREVAILING OTHERWISE.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 91% HIGH 92% MED 68% MED 73%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% 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:
WWW.WEATHER.GOV/GSP/AVIATION
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...JPT
NEAR TERM...MUNROE
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...MUNROE
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