« Back
NWS Peachtree City, Ga » Text Product » GSP Area Forecast Discussion


Printer-friendly Version
Current Version              Previous Versions:   1  2  3  4  5  6  7  8  9  

Area Forecast Discussion

425
FXUS62 KGSP 260753
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
353 AM EDT THU MAR 26 2015

.SYNOPSIS...
WARM SOUTHERLY FLOW WILL GRADUALLY INCREASE AHEAD OF AN APPROACHING
COLD FRONT TODAY. THE COLD FRONT WILL CROSS THE WESTERN CAROLINAS
AND NORTHEAST GEORGIA TONIGHT. A TRAILING UPPER LEVEL DISTURBANCE
WILL THEN CROSS THE AREA FRIDAY THROUGH FRIDAY NIGHT. DRY AND COOL
HIGH PRESSURE WILL SETTLE IN OVER THE WEEKEND. A LOW PRESSURE
CLIPPER SYSTEM AND ASSOCIATED COLD FRONT WILL PASS OVER THE REGION
ON MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 345 AM...WEAK ISENTROPIC LIFT AT 295 K WILL SUPPORT WIDESPREAD
LOW CEILINGS AND PATCHY FOG EARLY THIS MORNING. THE THICK LOW CLOUDS
WILL LIKELY LINGER A FEW HOURS AFTER SUNRISE. IN ADDITION...SCT TI
WIDELY SCT -SHRA WILL CONTINUE ACROSS THE REGION THROUGH SUNRISE.
THE 0Z NAM INDICATES THAT LLVL WINDS WILL VEER FROM THE SOUTHWEST
SHORTLY AFTER SUNRISE...RESULTING LITTLE TO NO ISENTROPIC LIFT AND
ENDING UPSLOPE FLOW. CLOUD COVER MAY BEGIN TO THIN ONCE LLVL LIFT
HAS CEASED...ESPECIALLY FROM MID DAY THROUGH THE AFTERNOON.
INCREASING SUN AND MARGINALLY GUSTY SOUTHWEST WINDS SHOULD
RESULT IN MILD AFTERNOON TEMPERATURES ACROSS THE CWA. A BLEND OF
PREFERRED TEMPERATURE GUIDANCE YIELD HIGHS FROM AROUND 70 WITHIN THE
MTN VALLEYS TO THE MID TO UPPER 70S EAST OF I-85. DEWPOINTS WILL
RISE INTO THE 50S THIS AFTERNOON.

NEAR TERM MODELS INDICATE THAT A COLD FRONT WILL SLIDE ACROSS
EASTERN KY/TN THIS AFTERNOON...CROSSING THE SOUTHERN APPALACHIANS
BETWEEN 0Z-3Z...THEN PUSHING EAST OF THE PIEDMONT BY 9Z. POOLING
DEWPOINTS AND MILD TEMPERATURES SHOULD YIELD CAPE VALUES BETWEEN 500-
1000 J/KG ALONG AND AHEAD OF THE COLD FRONT. A BAND OF SHRA/TSRA IS
FORECAST TO REACH THE TN/NC LINE BETWEEN 0Z TO 3Z. I WILL INCREASE
POPS THROUGH THIS EVENING...PEAKING POPS AT 6Z IN THE HIGH LIKELY TO
CATEGORICAL RANGES. I WILL MENTION SHOWERS WITH CHC/SCHC OF TSRA. IN
THE WAKE OF THE FRONT...BRISK CAA WILL BUILD ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA. BY 12Z FRI...TN BORDER COUNTIES MAY
COOL H850 TEMPS TO 0 TO -2C. MIN TEMPERATURES ARE FORECAST TO RANGE
IN THE U30S WITHIN MTN VALLEYS TO MID TO UPPER 40S EAST. THE CAA
COULD SUPPORT A FEW TN BORDER -SHSN.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 315 AM THURSDAY...MODELS IN AGREEMENT THAT THERE WILL BE SOME
LINGERING PRECIP ACRS THE EASTERN HALF OF THE CWFA FRIDAY
MORNING...AS MOST UPGLIDE CONTINUES BEHIND THE SFC COLD FRONT. THIS
PRECIP WILL ALSO BE INCREASING DPVA...AS A SHARP UPPER TROF AXIS
APPROACHES FROM THE WEST. TEMPS WILL BE TRICKY...AS PRECIP/CLOUDS
DIMINISH FROM WEST TO EAST DURING THE AFTN HOURS. THICKNESSES FALL
QUICKLY AS WELL...SO EXPECT TEMPS TO ONLY RISE INTO THE 50S.

FRIDAY NIGHT...THERE WILL BE SOME LINGERING NW FLOW SHWR ACTIVITY AS
A VIGOROUS VORT MAX ROUNDS THE BASE OF THE UPPER TROF AS IT CROSSES
THE NC MTNS. MEANWHILE...850 MB TEMPS WILL FALL TO THE -4 TO -8C
RANGE. SO EXPECT MAINLY SNOW SHWRS WITH SOME MINOR ACCUMS. STILL
THINK IT WILL BE SUB-ADVISORY. THE MTNS WILL LIKELY EXPERIENCE AN
ADVECTIVE FREEZE OVERNIGHT...WITH LOW TEMPS IN THE 20S. THE PIEDMONT
WILL SEE TEMPS IN THE 30S...WITH ISOLD FREEZING TEMPS AND POSSIBLY
SOME PATCHY FROST...IF WINDS DECOUPLE.

SATURDAY...THE LLVL CAA WILL CONTINUE...AS ANOTHER SHORTWAVE ROUNDS
THE BASE OF THE UPPER TROF. EXPECT NW FLOW SHOWERS TO DIMINISH
HOWEVER...AS MOISTURE WANES. TEMPS WILL BE ABOUT 15-20 DEG BELOW
NORMAL...WITH A BREEZE IN THE MTNS MAKING IT FEEL EVEN COLDER.

SATURDAY NIGHT...THE CENTER OF CANADIAN HIGH PRES WILL SETTLE IN
ACRS THE CWFA...USHERING IN THE COLDEST TEMPS WE/VE SEEN IN A COUPLE
WEEKS. A HARD FREEZE IS EXPECTED ACRS THE ENTIRE MTN ZONES...AND A
LIGHT-MODERATE FREEZE ELSEWHERE. MIN TEMPS SUNDAY MORNING LOOK TO BE
IN THE TEENS TO MID 20S IN THE MTNS AND MID 20S TO LWR 30S ACRS THE
PIEDMONT. THESE MIN TEMPS WILL APPROACH RECORD LOWS ACRS THE
PIEDMONT (SEE CLIMATE SECTION BELOW).

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...THE UPPER TROF WILL EXIT OFF THE EAST COAST
SUNDAY...AND A SHARP REBOUND IN HEIGHTS IS EXPECTED. SUNDAY WILL
STILL BE A CHILLY DAY...BUT EXPECTED TO BE AT LEAST A COUPLE
CATEGORIES WARMER THAN SATURDAY AFTER A COLD START. AS THE CENTER OF
SFC HIGH PRES SHIFTS EAST...WEAK RETURN FLOW SHUD COMMENCE. SUNDAY
NIGHT SHUD BE BACK TO NEAR NORMAL WITH LOWS IN THE MAINLY IN THE MID-
UPR 30S IN THE MTNS AND UPR 30S TO LWR 40S ACRS THE PIEDMONT.

MONDAY THRU WEDNESDAY...ANOTHER SHORTWAVE TROF WILL DIG INTO THE
GREAT LAKES AND USHER IN A CLIPPER LOW TO THE REGION. THE TRAILING
COLD FRONT OF THAT SYSTEM WILL CROSS THE CWFA EITHER MONDAY MORNING
(PER GFS) OR MONDAY EVENING (PER ECMWF). BOTH SOLNS SHOW ENUF
MOISTURE FOR A BAND OF PRECIP WITH THE FROPA. TEMPS BEHIND THE FRONT
WILL NOT BE THAT COLD AS THE AIR MASS WILL BE FROM THE PACIFIC. THE
GFS BRINGS A MORE VIGOROUS SOUTHERN STREAM SHORTWAVE BY
WEDNESDAY...WITH A RETURN OF POPS. THE ECMWF KEEPS THE AREA DRY.
GOING WITH THE SUPERBLEND THAT INCLUDES THE LATEST WPC
GUIDANCE...HAVE A SLGT CHC TO CHC POP ON MONDAY WITH THE
FRONT...THEN CHC POPS RETURN TUESDAY NIGHT THRU WEDNESDAY (MORE IN
LINE WITH THE GFS). TEMPS WILL BE NEAR OR SLIGHTLY ABOVE NORMAL
DURING THIS PERIOD.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AT KCLT...WEAK LLVL LIFT AND DEEP MOISTURE WILL SUPPORT RESTRICTIVE
CEILINGS THROUGH MID MORNING ACROSS THE TERMINAL. AT 6Z...TCLT AND
KGSP DETECTED SEVERAL PATCHES OF -RA/-DZ ACROSS THE REGION...WITH
THE HIGHEST REFLECTIVITY VALUES EAST OF CLT. MODEL SOUNDING AND
CLIMO INDICATE THAT IFR CEILINGS WILL LIKELY DEVELOP BY
9Z...POSSIBLY A LITTLE EARLIER. IFR CEILINGS AND ROUNDS OF
-RA/-DZ WILL CONTINUE UNTIL 14Z. A COLD FRONT IS EXPECTED TO SWEEP
EAST ACROSS THE CAROLINAS THIS EVENING. AS THE FRONT
APPROACHES...SOUTHWEST WINDS WILL STRENGTHEN TO AROUND 10 KTS...WITH
GUSTS NEAR 20 KTS BETWEEN 16Z-02Z. CLOUD BASES SHOULD LIFT TO 035-
080 KFT THIS AFTERNOON AND EARLY EVENING. THE POSITION OF THE COLD
FRONT IS FORECAST TO REACH THE I-85 CORRIDOR AROUND 6Z FRI. IT
APPEARS THAT SOUTHWEST WINDS WILL REMAIN THROUGH THE 6Z TAF
PERIOD...A PERIOD OF MVFR CEILINGS COULD DEVELOP ALONG AND AHEAD OF
THE COLD FRONT.

ELSEWHERE...TERMINAL CONDITIONS WILL LIKELY REMAIN SIMILAR TO KCLT.
KAND/KGSP/KGMU/KAVL RECEIVED SOME RAINFALL WED AFTERNOON/EVENING. IT
IS POSSIBLE THAT VIS MAY FALL ACROSS AREAS OF WET SOIL.
OTHERWISE...WEAK LLVL LIFT AND UPSLOPE FLOW WILL SUPPORT IFR
CEILINGS THROUGH MID MORNING. CLOUDS ARE FORECAST TO IMPROVE TO VFR
BY MID DAY...AS SOUTHWEST WINDS BECOME MARGINALLY GUSTY. A COLD FRONT
WILL PUSH ACROSS THE MTNS LATE THIS AFTERNOON AND EVENING. A FIELD
OF WEAK CAPE IS EXPECTED TO DEVELOP ALONG AND AHEAD OF THE
FRONT...POSSIBLY SUPPORTING TSRA. THE COVERAGE AND TIME WINDOW OF
THE TSRA APPEAR TOO LIMITED TO MENTION IN THE 6Z TAFS.

OUTLOOK...IMPROVING CONDITIONS ARE LIKELY ON FRIDAY IN THE WAKE OF A
COLD FRONT...BUT SCATTERED SHOWERS WILL CONTINUE TO PRODUCE SOME
RESTRICTIONS. HIGH PRESSURE WILL BUILD OVER THE REGION BEGINNING
FRIDAY NIGHT PRODUCING VFR CONDITIONS.

CONFIDENCE TABLE...

            08-14Z        14-20Z        20-02Z        02-06Z
KCLT       HIGH  91%     HIGH  84%     HIGH 100%     HIGH  92%
KGSP       HIGH  88%     HIGH  91%     HIGH 100%     HIGH  82%
KAVL       HIGH  93%     MED   79%     HIGH 100%     MED   70%
KHKY       MED   65%     HIGH  81%     HIGH 100%     MED   75%
KGMU       HIGH  88%     HIGH  87%     HIGH 100%     HIGH  82%
KAND       HIGH  82%     HIGH  87%     HIGH 100%     HIGH  80%

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

&&

.CLIMATE...
RECORD MINIMUM TEMPERATURES FOR MARCH 28TH...

GSP  26  1982
CLT  25  1982
AVL  11  1887

RECORD MINIMUM TEMPERATURES FOR MARCH 29TH...

GSP  26  1899
CLT  26  2013
AVL  19  1982

&&

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

&&

$$
SYNOPSIS...ARK
NEAR TERM...NED
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...NED
CLIMATE...



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