Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 060555
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1255 AM EST FRI MAR 6 2015

.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL BUILD ACROSS THE REGION ON FRIDAY...
THEN GRADUALLY WARMING THROUGH THE WEEKEND. EXPECT A COUPLE OF LOW
PRESSURE SYSTEMS TO DEVELOP OUT OF THE GULF NEXT WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 920 PM...PRECIP WILL BE EAST OF THE AREA SOON. CANNOT RULE OUT
SOME LINGERING FLURRIES ACROSS THE TN BORDER COUNTIES...BUT NO
ADDITIONAL ACCUMS EXPECTED. ATTENTION TURNS TOWARD THE COLD
TEMPERATURES OVERNIGHT. WITH THE EARLIER SNOW/RAIN ACROSS THE NC
MTNS AND THE RAIN ACROSS THE NC FOOTHILLS AND PIEDMONT...THE VERY
COLD TEMPS MAY LEAD TO AREAS OF BLACK ICE OVERNIGHT. WILL ISSUE A
BLACK ICE ADVISORY FOR THESE AREAS. ALTHOUGH THERE WAS ALSO RAIN
ACROSS THE UPSTATE AND NE GA...TEMPS WILL NOT BE QUITE AS COLD OVER
THESE AREAS. THEREFORE...WILL ISSUE AN SPS FOR PATCHY BLACK ICE
HERE. OTHERWISE...GOING FCST OF DIMINISHING WINDS AND GRADUALLY
CLEARING SKIES IS ON TRACK WITH ONLY MINOR CHANGES.

AS OF 635 PM...MAIN AREA OF PRECIP MOVING INTO THE PIEDMONT ATTM AND
SHUD BE EAST OF THE AREA BY 10 PM. THERE WILL BE SOME LINGERING SNOW
ACROSS THE TN BORDER COUNTIES...BUT ONLY VERY LIGHT OR NO ADDITIONAL
ACCUMS ARE EXPECTED. GIVEN THE LINGERING WET ROADS AND VERY COLD
TEMPS ACROSS NC...WILL ISSUE A WSW FOR BLACK ICE AFTER THE PRECIP
ENDS...TO AVOID CONFUSION WITH ANY WINTRY PRECIP POTENTIAL. TEMPS
WILL BE A LITTLE WARMER OVER THE UPSTATE AND NE GA...SO EXPECT ONLY
PATCHY BLACK ICE THERE. WILL ISSUE AN SPS FOR THESE LOCATIONS.
OTHERWISE...EXPECT THE WINDY CONDITIONS ACROSS THE MTNS TO SLOWLY
DIMINISH OVERNIGHT...WITH WINDS ELSEWHERE DIMINISHING SOONER. CANNOT
COMPLETELY RULE OUT A SLEET PELLET OR SNOW FLAKE OUTSIDE OF THE
MTNS...BUT THEY WOULD BE VERY BRIEF WITH NO ACCUMS. HAVE UPDATED
TEMP TRENDS TO FOLLOW LATEST CONDITIONS AND GUIDANCE...WHICH KEEPS
LOWS AS IS...BUT SHOWS A SLOWER DECLINE UNTIL LATER THIS EVENING OR
OVERNIGHT.

AS OF 230 PM...PRECIP SHIELD SEEMS TO BE THINNING/WEAKENING...AS
BEST UPPER DIVERGENCE (RIGHT ENTRANCE JET REGION) SHIFTS EAST AND
UPGLIDE OVER THE SHALLOW FRONTAL ZONE DIMINISHES. THIS ON TOP OF
STILL NO REPORTS OF FREEZING RAIN OR SNOW IN THE MTNS HAS ME
SKEPTICAL THAT WE/LL HAVE ANY ISSUES IN THE NC MTNS/WSW AREA LATE
THIS AFTN. WITH THAT SAID...I STILL HAVE ENUF OVERLAP OF LIKELY POPS
AND SOME SUB-FREEZING TEMPS CREEPING IN ALONG THE TN LINE THAT I
WILL LET THE WSW RIDE WITH THIS UPDATE. IT IS SET TO EXPIRE AT 6 PM.

ELSEWHERE...THE FRONT IS SLOWLY PROGRESSING SOUTHWARD THRU THE
UPSTATE AND NE GA. SOME SITES HAVE REPORTED SOME STOUT GUSTY WINDS
WITH THE FROPA AND NOTABLE TEMP DROPS OF 10-20 DEG WITHIN AN HOUR OR
TWO/S TIME.

TONIGHT...MENTIONABLE POP COMPLETELY ENDS BY 06Z ACRS THE CWFA...BUT
CLOUDS AND SOMEWHAT BREEZY N/NE WINDS LINGER OVERNIGHT. TEMPS ARE
EXPECTED TO DROP INTO TEENS TO LWR 20S IN THE MTNS AND GENERALLY MID
20S TO LWR 30S ACRS THE PIEDMONT. THE MTNS WILL SEE TEMPS DROP BELOW
FREEZING FAIRLY QUICKLY THIS EVENING. SO SOME SORT OF BLACK ICE
THREAT IS POSSIBLE...AND AN SPS OR WSW MAY BE NEEDED.
HOWEVER...LITTLE OR NO SNOW HAS FALLEN SO FAR...SO THAT MAY HELP
LIMIT ICE POTENTIAL IF ROADS CAN DRY OFF THIS EVENING.

FRIDAY...THE AXIS OF A POSITIVELY-TILTED UPPER TROF WILL SWING THRU
THE AREA...WHILE COLD DRY HIGH PRES BUILDS IN FROM THE NORTH. TEMPS
WILL BE ABOUT 15-20 DEG BELOW NORMAL UNDER SUNNY TO MOSTLY SUNNY
SKIES.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
AS OF 1230 PM EST THURSDAY...THE SHORT RANGE PART OF THE FORECAST
APPEARS TO BE RATHER QUIET...WITH THE UPPER PATTERN SLOWLY
DEAMPLIFYING. THE PATTERN WILL SUPPORT WEAKENING HIGH PRESSURE
ACROSS MOST OF THE SOUTHEAST THROUGH THE BETTER PART OF THE
WEEKEND...WITH TEMPS REBOUNDING CLOSER TO NORMAL. ONCE WE GET TO
SUNDAY...THE CONFLUENT AREA OF THE SPLIT UPPER FLOW WILL MIGRATE EWD
OVER THE MID-ATLANTIC AND CAROLINAS. THIS DEVELOPMENT WILL MAKE THE
TIMING OF THE NEXT SYSTEM...IN THE SRN BRANCH OF THE SPLIT FLOW...A
BIT MORE PROBLEMATIC. FOR NOW...HAVE ELECTED TO KEEP THE DEVELOPMENT
OF PRECIP OFF TO THE WEST THROUGH THE END OF DAYLIGHT ON SUNDAY...
BUT THIS COULD EASILY HAVE TO BE MOVED UP.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 2 PM EST THURSDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
MONDAY WITH PERSISTENT BROAD UPPER TROFFING OVER THE NORTHEASTERN
CONUS AND WEAK UPPER RIDGING BEGINNING TO BUILD OVER THE SE REGION.
OVER THE NEXT COUPLE OF DAYS...A SOUTHERN STREAM TROF PERSISTS AND
AMPLIFIES OVER THE TX/NEW MEXICO REGION AND TRIES TO SPIN OFF A
CLOSED H5 LOW. AT THE SAME TIME...FLAT UPPER RIDGING PERSISTS OVER
THE FCST AREA THRU THE REMAINDER OF THE MEDIUM RANGE. IT IS
NOTEWORTHY THAT THE ECMWF MAINTAINS AN EMBEDDED H5 SHORTWAVE WITHIN
THE SOUTHERN STREAM AND MOVES THE FEATURE TO OUR DOORSTEP BY NEW DAY
7...YET THIS FEATURE IS NOT DEPICTED ON THE NEWER RUN OF THE GFS.

AT THE SFC...THE LONG RANGE MODELS ARE COMING INTO BETTER AGREEMENT
WITH REGARDS TO THE DEPARTURE OF THE HIGH TO OUR EAST EARLY MONDAY.
THE MODELS HAVE A BROAD AREA OF DEEP LYR MOISTURE OVERSPREADING THE
CWFA FROM THE SW THRU THE DAY. BY 00Z TUES...DEEP LYR MOISTURE IS
OVER THE MAJORITY OF THE FCST AREA AND REMAINS IN PLACE WELL INTO
WED. BEYOND THIS POINT...THE GFS STRENGTHENS THE PARENT HIGH TO OUR
NORTH AND DRIES THE CAROLINAS OUT FROM NORTH TO SOUTH SO BY 12Z
THURS...THE ENTIRE CWFA IS DRY. THE ECMWF...HOWEVER...KEEPS THE DEEP
MOISTURE OVER THE REGION THRU NEW DAY 7.

AS FOR THE SENSIBLE FCST...I INCREASED POPS TO SOLID CHANCE FOR MOST
OF THE CWFA BY MON EVENING ACCOUNTING FOR A MORE MOIST GFS SOLUTION.
I KEPT SOLID CHANCE POPS FOR TUES AND EARLY WED WITH SLIGHT TO SOLID
CHANCE FOR THE REMAINDER OF THE PERIOD OWING TO A PATTERN THAT IS
WEAKLY FORCED OVERALL. I LOWERED TEMPS A DEGREE OR 2 FOR TUES AND
WED WITH HIGHS NOW JUST BELOW CLIMATOLOGY.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AT KCLT...STRATOCU STUCK UNDER LLVL INVERSION SHOULD BE ABLE TO
LINGER IN SOME FORM UNTIL AFTER DAYBREAK. AREAS OF MVFR CIGS ARE
CURRENTLY SCATTERED ACRS THE PIEDMONT AND COULD EASILY DEVELOP
ATOP THE TERMINAL...WILL CONTINUE TO MONITOR THE TREND. BRISK NE
WINDS WITH EVEN LOW AMPLITUDE GUSTS WILL REMAIN THROUGH ABOUT
MID-MORNING. FROM LATE MORNING AND THROUGH THE REST OF THE
PERIOD...WINDS WILL BECOME LIGHTER AND SKIES WILL BECOME CLEAR.

ELSEWHERE...VARYING DEGREES AND MAGNITUDES OF STRATOCU WILL GIVE
WAY TO AN OVERALL SCATTERED TREND AFTER SUNRISE...WITH CLEAR SKIES
AND LIGHTER WINDS THIS AFTERNOON AND TONIGHT.

OUTLOOK...VFR CONDITIONS EXPECTED THROUGH THE WEEKEND.

CONFIDENCE TABLE...

            13-19Z        19-01Z        01-07Z        07-12Z
KCLT       HIGH  95%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       MED   74%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       MED   77%     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...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ033-
     035>037-048>053-056>059-062>065-068>072-082-501>510.
SC...NONE.

&&

$$
SYNOPSIS...NED
NEAR TERM...ARK/RWH
SHORT TERM...PM
LONG TERM...JPT
AVIATION...CSH/RWH


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