Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 241745
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
145 PM EDT SUN MAY 24 2015

.SYNOPSIS...
DRY CANADIAN HIGH PRESSURE WILL REMAIN ATOP THE REGION TODAY. THE
HIGH TAKES ON A SUMMERTIME BERMUDA HIGH PATTERN ON MEMORIAL DAY AND
REMAINS THERE THROUGH THE WEEK. A MOIST SOUTHERLY FLOW DEVELOPS WITH
INCREASING CHANCES FOR CONVECTION.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 140 PM EDT SUNDAY...CURRENT FCST REMAINS ON TRACK.  THEREFORE
OTHER THAN TWEAKS OF TEMPERATURES/DEWPOINTS...NO CHANGES MADE.  FULL
FCST DISCUSSION TO FOLLOW WITHIN THE HOUR.

PREVIOUS DISCUSSION...

AS OF 230 AM...A LARGE UPPER RIDGE WILL REMAIN OVER THE AREA
TODAY...WHILE THE CENTER OF THE SFC RIDGE SETS UP OFF THE MID
ATLANTIC COAST. THE INCREASING SOUTHEASTERLY LLVL FLOW ATOP THE CWFA
SHUD BEGIN TO TRANSPORT SOME SHALLOW ATLANTIC MOISTURE INTO THE
AREA. HOWEVER...MID LVL SUBSIDENCE WILL RESULT IN ANOTHER DRY DAY.
THICKNESSES WILL BE SIMILAR TO YESTERDAY...WITH MAX TEMPS ABOUT A
CATEGORY ABOVE NORMAL.

TONIGHT...MODELS IN GOOD AGREEMENT ON A SHALLOW MOIST LAYER REACHING
THE UPPER SAVANNAH VALLEY AND SOUTHERN BLUE RIDGE ESCARPMENT
OVERNIGHT. SO EXPECT STRATUS TO DEVELOP...AT LEAST ACRS THE WESTERN
HALF OF THE CWFA BY DAYBREAK MONDAY. MOST OF THE GUIDANCE TRIES TO
SQUEEZE OUT A FEW LIGHT SHWRS ALONG THE ESCARPMENT WITHIN THE
SOUTHEASTERLY UPSLOPE FLOW. HOWEVER...FCST SNDGS SHOW THE DEPTH OF
THE NEAR-SATURATED LAYER TO BE VERY SHALLOW. SO WILL GO WITH A DRY
FCST OVERNIGHT. TEMPS WILL BE A COUPLE CATEGORIES ABOVE NORMAL
WITHIN THE SE FLOW AND INCREASING CLOUDS LATE.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 155 AM SUNDAY...THE UPPER RIDGE AXIS OVER THE AREA SLIDES TO
THE COAST ON MONDAY ALLOWING A SWLY FLOW TO DEVELOP. THIS PATTERN
HOLDS ON TUE WITH A SERIES OF WEAK SHORT WAVES SLIDING THRU THE FLOW
AND OVER OR NEAR THE CWFA. AT THE SFC...RIDGING FROM THE BERMUDA
HIGH WEAKENS ALLOWING A LOW LEVEL SLY TO SWLY FLOW TO DEVELOP AS
WELL. THIS WILL HELP CREATE A DEEP PLUME OF GULF MOISTURE WHICH
MOVES INTO THE AREA...ESPECIALLY THE WRN CWFA DURING THIS PERIOD.
THEREFORE...EXPECT SCT CONVECTION TO DEVELOP OVER THE WRN CWFA
MONDAY DIMINISHING TO NO CONVECTION OVER THE I-77 CORRIDOR. PRECIP
CHC INCREASES ACROSS THE BOARD ON TUE AS MOISTURE AND FORCING
INCREASE. ALTHOUGH THERE WILL BE A DIURNAL TREND TO THE CONVECTIVE
COVERAGE...EXPECT AT LEAST SOME SHRA TO LINGER THRU THE NITE GIVEN
THE COPIOUS LOW LEVEL MOISTURE AND GENERAL UPSLOPE FLOW. THE THREAT
OF SEVERE WEATHER WILL BE MITIGATED BY POOR LAPSE RATES AND
RELATIVELY WEAK INSTABILITY. ABOVE NORMAL TEMPS MON WILL REMAIN
NEARLY STEADY OR RISE A COUPLE OF DEGREES TUE DEPENDING ON LOCATION.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 315 AM SUNDAY...THE UPPER RIDGE AXIS OVER THE EAST COAST
WEAKENS AND ALLOWS A SERIES OF SHORT WAVES TO MOVE OVER OR NEAR THE
AREA THRU THE PERIOD. AT THE SFC...A BERMUDA HIGH REMAINS IN PLACE
OVER THE AREA IN A PATTERN MORE TYPICAL OF SUMMER. THIS KEEPS A
MOIST SWLY FLOW OVER THE AREA. THIS PATTERN WILL LEAD TO MAINLY
DIURNAL CONVECTION EACH DAY...POSSIBLY LINGERING THRU THE NITE WED
NITE. COVERAGE WILL LIKELY BE HIGHER WED AND THU THEN ON FRI AND
SAT...DUE TO GREATER MOISTURE EARLY IN THE PERIOD. TEMPS WILL REMAIN
ABOVE NORMAL THRU THE PERIOD.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD.  TAF
INITIALIZES WITH LIGHT/MODERATE SOUTHEAST FLOW BENEATH LOW VFR CU
FIELD AND HIGH LEVEL BKN CIGS.  EXPECTING THIS TO PREVAIL THROUGH
THE AFTERNOON INTO EARLY EVENING BEFORE LOW CLOUDS ERODE AFTER
SUNSET.  AS SOUTHEASTERLY FLOW CONTINUES THROUGH THE
OVERNIGHT...MOISTURE WILL ADVECT NORTH FROM THE ATLANTIC AROUND THE
WESTERN PERIPHERY OF THE OFFSHORE MID ATLANTIC RIDGE.  THUS...SKY
COVER WILL INCREASE AROUND DAYBREAK WITH MID CLOUDS SPREADING IN
AHEAD OF LOW VFR.  MVFR CIGS WILL LIKELY BE JUST TO THE
WEST...THEREFORE FURTHER CIG DETERIORATION IS POSSIBLE IN LATER TAF
ISSUANCE.  WINDS WILL REMAIN OUT OF THE SOUTH/SOUTHEAST DURING THIS
TIMEFRAME.

ELSEWHERE...MUCH THE SAME AS KCLT ABOVE WITH SOUTHERLY FLOW
PREVAILING UNDER LOW VFR CU AND HIGH LEVEL CIRRUS THIS AFTERNOON.
CIGS WILL BUILD IN FROM THE SOUTHWEST OVERNIGHT AS MOISTURE
ADVECTION AROUND THE ABOVE MENTIONED HIGH INTRUDES.  THUS...CARRIED
MVFR CIGS AT ALL SC SITES AND KAVL BY MID/LATE MORNING WITH A PERIOD
OF IFR AT KAND.  NO RESTRICTIONS EXPECTED AT KHKY.  ALL RESTRICTIONS
WILL IMPROVE AFTER SUNSET ATOP OF INCREASING SOUTHERLY FLOW.
SHRA/TSRA CHANCES WILL ALSO INCREASE TOMORROW OVER THE
WEST...HOWEVER CONFIDENCE REMAINS LOW ENOUGH TO LEAVE OUT OF TAF.

OUTLOOK...MOISTURE WILL GRADUALLY RETURN OUT OF THE SOUTH THRU THE
MIDDLE OF THE WEEK. SO INCREASED MORNING STRATUS...AND A RETURN OF
ISOLD TO SCATTERED AFTN/EVE SHRA/TSRA CAN BE EXPECTED BY TUESDAY-
WEDNESDAY.

CONFIDENCE TABLE...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     LOW   58%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     LOW   58%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     LOW   58%

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...ARK/CDG
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...CDG


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