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Area Forecast Discussion

336
FXUS62 KGSP 010748
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
348 AM EDT WED OCT 1 2014

.SYNOPSIS...
DRIER HIGH PRESSURE WILL LINGER OVER THE REGION THROUGH THURSDAY. A
STRONG COLD FRONT WILL THEN ARRIVE FROM THE NORTHWEST ON FRIDAY AND
MOVE OFFSHORE BY EARLY SATURDAY. IN THE FRONTS WAKE...A COOL AND DRY
AIRMASS WILL MOVE BACK OVER THE SOUTHEAST AND REMAIN IN PLACE OVER
THE WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE SOUTHERN
APPALACHIAN REGION FROM THE NORTHWEST ON TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
FOR THE REMAINDER OF THE PRE-DAWN HOURS...EXPECT AREAS OF FOG TO
EXPAND ACROSS THE REGION. FOG SHOULD BE DENSE IN SOME OF THE
MOUNTAIN VALLEYS. THE FOG SHOULD DISSIPATE AN HOUR OR TWO AFTER
SUNRISE.

THE NEXT 24 HOURS SHOULD BE RELATIVELY QUIET ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA. AN UPPER RIDGE WILL BUILD OVERHEAD
TODAY AND THEN THE AXIS OF THE RIDGE WILL MOVE EASTWARD TONIGHT AS
AN UPPER LOW ALONG THE NEW ENGLAND COAST MOVES FARTHER OFFSHORE. THE
RIDGE WILL SUPPORT WEAK HIGH PRESSURE AT THE SURFACE...AND A FAIRLY
SUBSTANTIVE SUBSIDENCE INVERSION. THE NAM IN PARTICULAR DEVELOPS
WIDELY SCATTERED SHOWERS THIS AFTERNOON ON THE BLUE RIDGE AND MOVES
THEM EAST THIS EVENING...AS THE CAP IS BROKEN OVER PARTS OF THE
PIEDMONT. THIS SEEMS UNLIKELY AND SUSPECT THE NAM SFC DEWPTS ARE TOO
HIGH AS USUAL. THINK THE GFS/ECMWF HAVE THE RIGHT IDEA THAT THE CAP
WILL BE FAR TOO STRONG AND THAT IT WILL REMAIN DRY. HAVE REMOVED ALL
MENTION OF SHOWERS FOR THAT REASON. TEMPS SHOULD BE A DEGREE OR TWO
WARMER THAN TUESDAY. HIGH PRESSURE REMAINS IN CONTROL TONIGHT WITH
PATCHY FOG POSSIBLE AGAIN AROUND DAYBREAK WEDNESDAY.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...ON THURSDAY...A RIDGE OF SFC HIGH PRESSURE
WILL REMAIN ACROSS THE REGION...UNDER THE AXIS OF A H5 RIDGE. H85
TEMPS ARE FORECAST TO RANGE FROM 16C ACROSS THE MTNS TO 15C ACROSS
THE PIEDMONT. THE COMBINATION OF MILD LLVL THICKNESSES AND PLENTIFUL
INSOLATION SHOULD SUPPORT HIGH TEMPERATURES NEAR 80 WITHIN THE MTN
VALLEYS TO MID 80S ACROSS THE PIEDMONT. FORECAST SOUNDINGS INDICATE
THAT A SIGNIFICANT H65 INVERSION WILL LINGER THROUGH THURSDAY. A
LAYER LLVL CIN SHOULD REMAIN THROUGH THE DAY...CAPPING SFC BASED
PARCELS.

ON FRIDAY...A DEEP MID LEVEL CLOSED LOW WILL TRACK SW ACROSS THE
NORTHERN PLAINS AND WESTERN GREAT LAKE REGION. SOUTH OF THE
LOW...THE AXIS OF THE MID LEVEL TROUGH WILL DIG EAST ACROSS THE
SOUTHEAST REGION. AT THE SFC...A STRONG COLD FRONT WILL PUSH FROM
MIDDLE TN 12Z FRIDAY TO THE CAROLINA COAST BY 12Z SATURDAY. MID AND
UPPER LEVEL FORCING WILL INCREASE AS A SHORT WAVE AND BAND OF JET
DIVERGENCE CROSSES THE SOUTHERN APPALACHIANS AFTER 12Z SATURDAY. THE
LOW LEVEL ENVIRONMENT WILL FEATURE CAPES BETWEEN 1000-1500 J/KG WITH
HELICITY VALUES BETWEEN 50-100 M2/S2. THIS ENVIRONMENT SHOULD
SUPPORT THE DAYTIME PASSAGE OF A PRE FRONTAL BAND OF CONVECTION
ACROSS THE HIGH TERRAIN. I WILL INCREASE POPS TO CATE TO HIGH LIKELY
ACROSS THE CWA...ESPECIALLY FRIDAY AFTERNOON. GIVEN THE
ENVIRONMENT...IT IS POSSIBLE THAT WELL ORGANIZED QLCS COULD DEVELOP
FRIDAY AFTERNOON OR EVENING. HOWEVER...THE POSSIBILITY OF SVR WEATHER
APPEARS TOO LIMITED TO HIGHLIGHT IN THIS MORNINGS HWO. TEMPERATURES
WILL BE LIMITED BY THICK CLOUDS AND RAINFALL...HIGHS SHOULD REMAIN
AROUND 5 DEGREES BELOW NORMAL.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...ON SATURDAY...STRONG H85 CAA WILL OCCUR
ACROSS THE REGION...FALLING FROM 10C OVER AVL AT 6Z TO 3C BY 12Z.
LOW TEMPERATURES ARE FORECAST TO RANGE FROM THE MID 40S ACROSS THE
HIGH TERRAIN TO THE MID 50S ACROSS THE PIEDMONT. HIGH TEMPERATURES
WILL LIKELY RANGE 5 TO 8 DEGREES BELOW NORMAL. SUNDAY SHOULD SEE THE
COOLEST TEMPERATURES OF THE PERIOD. THE CENTER SFC HIGH PRESSURE IS
FORECAST TO REACH THE AL/GA LINE BY 12Z SUNDAY. CONDITIONS ACROSS
THE REGION WILL FEATURE DRY...CALM...AND LIMITED SKY COVER. IN
ADDITION...CAA MAY PUSH H85 TEMPS ACROSS THE NRN MTNS FROM 0C TO
-1.5C. SUNDAY MORNING...MINS IN THE MID 30S SHOULD BE COMMON ACROSS
MTN RIDGES. ELSEWHERE....VALUES ARE FORECAST TO RANGE IN THE MID TO
U40S.

EARLY NEXT WEEK...THE CENTER OF HIGH PRESSURE WILL PUSH OFF THE
CAROLINA COAST AS ANOTHER COLD FRONT APPROACHES FROM THE WEST. THIS
PATTERN SHOULD ADVECT WARMER TEMPERATURES AND MOISTURE ACROSS THE
SOUTHERN APPALACHIAN REGION. TEMPERATURES WILL MODIFY THROUGH THE
LATE EXTENDED PERIOD...RETURN TO NEAR NORMAL BY TUESDAY. IN
ADDITION...I WILL MENTION DEVELOPING WIDELY SCATTERED SHOWERS ACROSS
THE CWA ON TUESDAY.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...FOG WAS GRADUALLY DEVELOPING ACROSS PARTS OF THE NC
PIEDMONT AS OF 06Z. THINK THAT EVENTUALLY THE MVFR VISIBILITY WILL
SURROUND KCLT AND WILL PROBABLY BE IFR/LIFR AT OUTLYING SPOTS.
HOWEVER...EXPECT KCLT TO BE SLOW TO SEE FOG DEVELOPMENT. DEWPT
DEPRESSION REMAINS 3 DEGREES ON THE MOST RECENT OBSERVATION. WILL
ADD A TEMPO PERIOD OF MVFR FOG IN THE 09Z-13Z TIME FRAME. IF
OBSERVATIONS DROP TO MVFR...THEN IFR WILL BE A DISTINCT POSSIBILITY
AND THE TAF WILL BE AMENDED TO INCLUDE THAT IN A TEMPO. THE FOG
SHOULD BURN OFF QUICKLY ONCE AGAIN. FROM MID MORNING ONWARD...EXPECT
FEW/SCT STRATOCU WITH BASES AROUND 050 AND A LIGHT S/SW WIND. KEPT
THOSE CONDITIONS THROUGH THE END OF THE CURRENT PERIOD.

ELSEWHERE...SIMILAR CONDITIONS AS KCLT...ESP KGSP/KGMU. KHKY/KAND
SHUD SEE MVFR FOG OVERNIGHT...WITH LITTLE TO NO CHC OF LOW CLOUDS.
KAVL THE MAJOR EXCEPTION...AS USUAL...WITH ANOTHER ROUND OF VLIFR
POSSIBLE. SHOULD BE A QUICK RETURN TO VFR BY MID MORNING...WITH
CONVECTIVE CU DEVELOPING ONCE AGAIN ALL AREAS. LIGHT WIND BECOMES
CALM OVERNIGHT THEN SSW WED AFTERNOON. KAVL WILL SEE AN UPVALLEY
WIND DURING THE MORNING AND INTO THE AFTERNOON...BECOMING DOWNVALLEY
IN THE LATE AFTERNOON AND EVENING.

OUTLOOK...FOG/VSBY CONCERNS REMAIN EARLY THURSDAY MORNING. A FRONT
WILL APPROACH ON FRIDAY WHICH COULD TRIGGER SOME SHOWERS AND
THUNDERSTORMS...WITH ASSOCIATED RESTRICTIONS POSSIBLE...AS IT MOVES
ACROSS THE REGION FRIDAY AFTERNOON AND NIGHT. VFR RETURNS ON
SATURDAY THROUGH THE REST OF THE WEEKEND.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-07Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       MED   65%     HIGH  86%     HIGH 100%     HIGH 100%
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: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...NED
NEAR TERM...PM
SHORT TERM...NED
LONG TERM...NED
AVIATION...PM






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