Area Forecast Discussion
Issued by NWS Greer, SC

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS62 KGSP 021459
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1059 AM EDT SUN AUG 2 2015

.SYNOPSIS...
DRY HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE AREA THROUGH
MONDAY. LOW LEVEL MOISTURE WILL GRADUALLY RETURN THROUGH THE WEEK AS
ANOTHER COLD FRONT APPROACHES FROM THE NORTH THEN MOVES INTO THE
AREA AND STALLS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM EDT SUNDAY...DEWPOINTS ARE RUNNING A BIT LOWER THAN
FORECAST SO HAVE MADE SOME ADJUSTMENTS ACCORDINGLY. OTHER GRIDS IN
GOOD SHAPE FOR THE MOST PART. HRRR AND OTHER HIRES GUIDANCE DO STILL
WANT TO DEVELOP SOME CONVECTION OVER THE MOUNTAINS THIS AFTERNOON
DESPITE THE DRY DEWPOINTS...BUT ENOUGH LAPSE RATE ALOFT FOR SOME
MINIMAL CAPE VALUES...SO HAVE KEPT THE SLIGHT CHANCE POPS FOR THIS
AFTERNOON.

1045 UTC UPDATED...SKY COVER HAS BEEN UPDATED TO ACCOUNT FOR CIRRUS
CROSSING THE INTERSTATE 77 CORRIDOR AND MOVING INTO SW SN AND NE GA.
WINDS WERE UPDATED FROM THE LATEST NAM GUIDANCE.

AT 230 AM EDT SUNDAY...AN UPPER RIDGE WILL REMAIN OVER THE WESTERN
USA TODAY AND TONIGHT...WHILE A TROUGH PERSISTS OVER THE EAST.
WEAK...CHANNELED SHORTWAVE ENERGY WILL MOVE THROUGH BASE OF THE
TROUGH OVER VA TODAY. AT THE SURFACE...A STATIONARY FRONT WILL
REMAIN NEAR THE COASTS OF NC...SC AND GA. THE BULK OF MOISTURE
ASSOCIATED WITH THIS FEATURE WILL REMAIN SOUTHEAST OF OUR AREA...AS
WILL ASSOCIATED PRECIPITATION. MOISTURE IS EXPECTED TO INCREASE OVER
OUR AREA HOWEVER...AND FORECAST MODEL SOUNDINGS WILL BE SUPPORTIVE
OF CONVECTION THIS AFTERNOON AND EVENING IN THE MOUNTAINS.
TEMPERATURES WILL SLIGHTLY ABOVE NORMAL.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 205 AM SUNDAY...EXPECT ANOTHER QUITE DAY MONDAY BEFORE A
PATTERN CHANGE AND A RETURN THE MORE TYPICAL DIURNAL THUNDERSTORM
REGIME. AN UPPER TROF WILL BE OVER THE ERN US WITH DRY HIGH
PRESSURE IN PLACE AT THE SFC. EXPECT THE DEWPOINTS TO MIX OUT ONCE
AGAIN INTO THE 50S MOST PLACES...KEEPING INSTABILITY AT A MINIMUM.
THE GUIDANCE SHOWS A LOW PRESSURE SYSTEM FORMING OVER THE GULF AND
MOVING NE NEAR THE ATLANTIC COAST ALONG AN OLD FRONTAL BOUNDARY.
HOWEVER...MOST MDLS KEEP THE LOW SOUTH AND EAST OF THE AREA WITH
MINIMAL EFFECT OVER THE CWFA. THEREFORE...NO SIGNIFICANT CONVECTION
IS EXPECTED. TEMPERATURES WILL BE WELL ABOVE NORMAL.

THE UPPER TROF BEGINS TO LIFT TUE WITH A WLY FLOW DEVELOPING. AT THE
SFC...A WEAK FRONTAL SYSTEM SAGS INTO THE AREA FROM THE NORTH. A
MOIST LOW LEVEL FLOW RETURNS BRINGING INCREASE LOW LEVEL MOISTURE.
DEWPOINTS WILL MIX OUT...BUT ONLY TO AROUND 60. THIS WILL BRING AN
INCREASE IN INSTABILITY AND POTENTIAL FOR AFTERNOON CONVECTION.
STILL...COVERAGE APPEARS TO BE LIMITED TO ISOLATED...AND MAINLY OVER
NC. TEMPS WILL RISE A COUPLE OF DEGREES FROM MON.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 320 AM SUNDAY...THE PATTERN CHANGE IS FULLY UNDERWAY AT THE
BEGINNING OF THE MEDIUM RANGE. ZONAL FLOW ALOFT BRINGS A SERIES OF
SHORTWAVES ACROSS THE AREA THRU THU. STRONGER SHORT WAVES MOVE IN
BEGINNING FRI BRINGING A RETURN TO THE UPPER TROF TO THE EASTERN
CONUS. ANOTHER SHORTWAVE MOVES THRU ON SAT REINFORCING THE TROF. AT
THE SFC...A WEAK COLD FRONT SAGS SOUTH AND STALLS ACROSS THE AREA.
THE SHORTWAVES HELP DEVELOP A SERIES OF LOW PRESSURE CENTERS WHICH
THEN MOVE ALONG THE FRONT AND ACROSS THE AREA THRU FRI. THIS WILL
BRING INCREASING CHANCES OF MAINLY DIURNAL CONVECTION. THAT SAID...
CONVECTION COULD LINGER THRU THE NITE AS THE CWFA WILL BE IN THE
PATH OF ANY POTENTIAL MCS ACTIVITY. A STRONGER LOW PRESSURE CENTER
DEVELOPS ON SAT AND MOVES EAST OF THE AREA POSSIBLY DRAGGING THE
FRONT SOUTH OF THE AREA. HOWEVER...THE MOIST UNSTABLE AIR MASS WILL
LINGER...KEEPING THE CHC OF CONVECTION IN PLACE...ALTHOUGH WITH A
LOWER RESULTING POP. TEMPS SHOW A SLOW BUT STEADY COOLING TREND THRU
THE PERIOD...ENDING UP NEAR NORMAL BY SAT.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR. FEW TO OCCASIONALLY SCT CU GENERALLY 8-9KFT LATE THIS
MORNING AND WILL LIKELY LOWER SOME AS MIXING INCREASES...BUT
COVERAGE IS GENERALLY NOT EXPECTED TO BE SUFFICIENT FOR A CIG.
INSTABILITY WILL BE TOO LIMITED FOR CONVECTION. LIGHT WINDS WILL BE
FROM THE NE TODAY....VEERING SE TONIGHT. SOME GUIDANCE IS LEANING
TOWARD DAYBREAK FOG MONDAY MORNING AT SURROUNDING SITES...BUT OTHER
GUIDANCE IS LESS PESSIMISTIC.

ELSEWHERE...VFR. SO FAR MOUNTAIN FOG HAS BEEN LIMITED TO VALLEYS
WELL SW OF KAVL. HIGH VFR CIGS ARE POSSIBLE EARLY TODAY AS CIRRUS
MOVES OVERHEAD. LOW VFR CIGS LATER TODAY WILL BE POSSIBLE IN THE NC
MOUNTAINS WHERE CONVECTION WILL COULD OCCUR IN BETTER INSTABILITY.
LIGHT WINDS WILL BE FROM THE NE MORNING...EXCEPT AT KAVL WHERE THEY
WILL VEER FROM NW TO SE TODAY AND RETURN TO NW TONIGHT...AND KHKY
WHERE THEY BACK FROM NE TO N TONIGHT. GUIDANCE IS BECOMING MORE
SUPPORTIVE OF DAYBREAK FOG ON MONDAY...BUT THE BEST BET IS INITIALLY
IN MOUNTAIN VALLEYS WHERE COOL AIR WILL POOL.

OUTLOOK...GRADUALLY INCREASING PRECIPITATION/RESTRICTION CHANCES
THROUGH MID WEEK AS MOIST SOUTHERLY FLOW RETURNS.

CONFIDENCE TABLE...

            15-21Z        21-03Z        03-09Z        09-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     MED   66%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  94%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     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 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...TDP
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT/TDP


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.