Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 280716
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
316 AM EDT THU MAY 28 2015

.SYNOPSIS...
A BERMUDA HIGH PATTERN WILL REMAIN ACROSS THE REGION INTO THE
WEEKEND BEFORE A COLD FRONT PUSHES IN FROM THE NORTH EARLY NEXT
WEEK.  THIS FRONT WILL THEN WEAKEN AND STALL OVER THE AREA THROUGH
THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 AM...CONVECTION OVER CENTRAL GA DIMINISHING AS IT SLOWLY
MOVES NE TOWARD THE SAVANNAH RIVER. HOWEVER...A FEW CELLS CONTINUE
TO REGENERATE ALONG THE LEADING EDGE OF THE WEAKENING COLD POOL. IF
THE CELLS CAN MAINTAIN THEMSELVES...THIS ACTIVITY WOULD MOVE INTO
OUR NE GA...AND POSSIBLY...WRN UPSTATE COUNTIES. IF THIS DOES
HAPPEN...THE CELLS SHOULD BE SHORT LIVED AND DISSIPATE BEFORE
DAYBREAK. OTHERWISE...EXPECT PATCHY FOG AND/OR LOW CLOUDS THIS
MORNING. SHOULD BE MORE DIURNAL CONVECTION TODAY AS PW VALUES RISE
ABOVE NORMAL AND A WEAK SHORT WAVE AND UPPER DIVERGENCE MOVE INTO
THE AREA. MODERATE INSTABILITY DEVELOPS BUT SHEAR IS WEAK. DCAPE
VALUES BETWEEN 500 J/KG AND 750 J/KG DEVELOP ALONG WITH DECENT SFC
DELTA THETA-E VALUES. HOWEVER...THERE WILL BE QUITE A BIT OF
CONVECTIVE DEBRIS CLOUDS ACROSS THE AREA TODAY WHICH COULD LIMIT
HEATING. ALL THAT SAID...ISOLATED SVR STORMS ARE POSSIBLE WITH
DAMAGING WINDS THE MAIN THREAT. THE CONVECTION SHOULD BE DIURNAL IN
NATURE...BUT COULD LINGER WELL INTO THE EVENING...AND POSSIBLY EARLY
OVERNIGHT...BEFORE DISSIPATING. HIGHS WILL BE NEAR TO 5 DEGREES
ABOVE NORMAL WITH LOWS AROUND 5 TO 10 DEGREES ABOVE NORMAL.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...AN UPPER RIDGE WILL PERSIST ALONG THE EAST
COAST...WHILE A WEAK TROF WILL SLOWLY CROSS THE CENTRAL-NORTHERN
PLAINS FRIDAY THRU SATURDAY. A SFC RIDGE AXIS WILL LINGER ACROSS THE
AREA...EXTENDING WESTWARD FROM THE NORTH ATLANTIC TO THE FL
PANHANDLE. THE MODELS AGREE THAT THIS RIDGE WILL HELP KEEP THINGS
MORE CAPPED...ESP ON SATURDAY. HOWEVER...THERE WILL STILL BE
SCATTERED MTN CONVECTION BOTH DAYS...WITH ISOLD CONVECTION POSSIBLE
ACRS THE PIEDMONT. SATURDAY WILL PROBABLY HAVE THE LEAST COVERAGE
PER MODEL CONSENSUS. TEMPS WILL BE A COUPLE CATEGORIES ABOVE NORMAL
FOR DAYTIME HIGHS...AND A FEW CATEGORIES ABOVE NORMAL FOR OVERNIGHT
LOWS...AS AIR MASS REMAINS HUMID. FCST SNDGS SHOW MODEST INSTBY ON
FRIDAY...WITH WEAK SHEAR. SO EXPECT SLOW-MOVING STORMS PRODUCING
HEAVY RAINFALL AS THE MAIN THREAT...WHILE A SEVERE WIND THREAT WILL
BE LOW. SATURDAY HAS EVEN LESS INSTBY...SO OVERALL HEAVY RAIN AND
SEVERE THREATS WILL BE VERY ISOLATED.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 245 AM THURSDAY...THE LATEST MEDIUM RANGE GUIDANCE HAS BEEN
TRENDING TOWARD BREAKING OFF THE SOUTHERN END OF THE APPROACHING
SHORTWAVE OVER THE MID MS VALLEY ON SUNDAY...CLOSING OFF A WEAK
CLOSED UPPER LOW INVOF THE MID SOUTH MONDAY THRU WEDNESDAY. THIS
ALLOWS THE EAST COAST RIDGE TO PERSIST THRU EARLY NEXT WEEK. THIS
SLOWS DOWN THE APPROACHING COLD FRONT. THE 00Z GFS AND ECMWF NOW
KEEP THE FRONT NORTH OF THE AREA THRU THE WEEKEND...THEN SLOWLY BACK
DOOR THE FRONT EARLY NEXT WEEK...AS HIGH PRES SETTLES IN ACRS THE
NORTHEAST STATES. IN ANY CASE...THERE BE A RETURN TO ABOVE CLIMO
POPS EACH DAY NEXT WEEK. TEMPS WILL BE ABOUT 5-8 DEG ABOVE NORMAL ON
SUNDAY...THEN BACK TO JUST A CATEGORY ABOVE NORMAL FOR MONDAY AND
TUESDAY...WITH INCREASED COVERAGE OF AFTN/EVE CONVECTION. OVERNIGHT
LOWS ARE NEARLY THE SAME EACH NIGHT WITHIN THE HUMID AIR MASS. THE
ATMOSPHERE WILL CONTINUE TO BE WEAKLY SHEARED ATOP THE CWFA...SO
EXPECT LOCALLY HEAVY RAIN TO BE THE MAIN THREAT AGAIN NEXT
WEEK...WITH A MARGINAL/ISOLATED SEVERE WIND/HAIL THREAT EACH DAY.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AT KCLT...GUIDANCE IS HOMING IN ON LOW CLOUDS AND NOT FOG CREATING
THE MVFR RESTRICTIONS EARLY THIS MORNING. HAVE GONE WITH MVFR BY 10Z
THEN LIFTING TO LOW VFR BY 14Z AND HIGHER VFR BY 17Z. PROB30
CONTINUES WITH DIURNAL CONVECTION EXPECTED. LIGHT SLY WIND BECOMES
CALM THIS MORNING THEN BACK TO SLY AFTER DAYBREAK.

ELSEWHERE...CONVECTION TO THE WEST DISSIPATING RAPIDLY AND TAKING ON
A NORTHWARD TRAJECTORY. DO NOT EXPECT ANY PRECIP THIS MORNING. MVFR
CLOUDS HAVE DEVELOPED AT KAVL...AND EXPECT CONDITIONS TO DETERIORATE
OVERNIGHT GIVEN THE EVENING RAIN AND FCST SOUNDINGS. STILL A
QUESTION OF HOW LOW WILL CONDITIONS FALL...BUT IFR SEEMS LIKELY.
HAVE LIMITED IT TO 1SM AND OVC005 FOR NOW...BUT LIFR OR EVEN VLIFR
POSSIBLE. ELSEWHERE...FCST SOUNDINGS LOOK LIKE FOG SO HAVE GONE
WITH MVFR FOR NOW...BUT IFR POSSIBLE. BETTER CHC AT KAND...SO HAVE
TEMPO IFR NEAR DAYBREAK. SHOULD BE A RELATIVELY QUICK RETURN TO VFR
AFTER DAYBREAK FOR ALL BUT KAVL WHERE MVFR CIGS LINGER THRU THE
MORNING. PROB30 CONTINUES WITH DIURNAL CONVECTION EXPECTED.
GENERALLY CALM WINDS THIS MORNING BECOME SLY OR SWLY THRU THE DAY.
KAVL THE EXCEPTION WHERE CALM WIND BECOMES NLY AFTER DAYBREAK THEN
SLY FOR THE AFTERNOON.

OUTLOOK...MOIST SW FLOW WILL CONTINUE TO AFFECT THE TERMINAL
FORECAST AREA THROUGH THE UPCOMING WEEKEND...AS A COLD FRONT LAYS
OVER TO THE NORTH OF THE AREA. EXPECT POCKETS OF MORNING FOG AND/OR
STRATUS MOST DAYS...WITH CONTINUED CHANCES OF AFTN/EVENING SHRA/TSRA
EACH DAY.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH  81%     HIGH  92%     HIGH 100%     HIGH 100%
KGSP       HIGH  96%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       LOW   55%     HIGH  85%     HIGH 100%     HIGH  96%
KHKY       HIGH  86%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH  92%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH  88%     HIGH  83%     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...ARK
NEAR TERM...RWH
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...RWH


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