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 111456
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
956 AM EST THU FEB 11 2016

.SYNOPSIS...
HIGH PRESSURE WILL MOVE ACROSS THE REGION TODAY AND TONIGHT. A
FAST-MOVING UPPER DISTURBANCE WILL BRING A BRIEF CHANCE OF
PRECIPITATION TO PARTS OF THE AREA FRIDAY. A STRONGER DOME OF
CANADIAN HIGH PRESSURE WILL SETTLE IN FOR THE WEEKEND...USHERING
IN ANOTHER PERIOD OF COLD TEMPERATURES. THIS WILL BE FOLLOWED
BY ANOTHER WEATHER SYSTEM WHICH WILL PRODUCE A BETTER CHANCE OF
PRECIPITATION EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
1500 UTC UPDATE...SKY COVER WAS ADJUSTED PER INFRARED SATELLITE
IMAGERY...RESULTING IN A DECREASE EAST OF THE MOUNTAINS. WINDS WERE
UPDATED FROM A BLEND OF THE LATEST NAM AND ADJMAV...WITH ONLY A
SLIGHT DECREASE NOTED. MAXIMUM TEMPERATURES WERE LOWERED SLIGHTLY
BASED ON A MODEL BLEND. SNOWFALL ON THE TN BORDER WILL BE ALLOWED
TO DECREASE THIS MORNING PER RADAR TRENDS.

AS OF 615 AM...A RELATIVELY TIGHT UPPER HEIGHT GRADIENT PERSISTS
OVER THE CWFA TODAY...WITH UPPER TROUGH AXIS OVER THE ATLANTIC
COAST. NORTHWEST FLOW INTO THE APPALACHIANS WILL CONTINUE...BUT
WILL GRADUALLY WEAKEN IN RESPONSE TO WEAKENING GRADIENT BEHIND THE
DEPARTING TROUGH. BAND OF CLOUD COVER OVER KY/TN HAS SHIFTED NEWD
AS EXPECTED...AND WILL PROVIDE A CONTINUED SOURCE OF MOISTURE FOR
LIGHT SNOW SHOWERS IN THE UPSLOPE AREAS THRU THE FIRST HALF OF THE
DAY. PER RADAR MOSAIC...MOST PRONOUNCED BAND CURRENTLY POINTED
INTO MADISON CO IS SET TO SHIFT TOWARD THE NORTH...SO A BURST
OF SNOW IS EXPECTED IN THE NRN MTNS BEFORE THE SHOWERS FINALLY
TAPER OFF AT MIDDAY. THE DOWNSLOPE FLOW...RISING THICKNESSES...AND
PARTLY TO MOSTLY SUNNY SKIES WILL BRING MAX TEMPS UP A COUPLE OF
CATEGORIES FROM WEDNESDAY/S VALUES. THAT WILL STILL BE ABOUT 10
DEGREES BELOW CLIMO.

HEIGHTS RISE INTO THIS EVENING AS BROAD HIGH PRESSURE MOVES OUT OF
THE MID-MISSISSIPPI VALLEY...CENTERING OVER THE TIDEWATER REGION
BY EARLY FRI. HOWEVER...QUICKLY COMING IN THE WAKE OF THE HIGH IS A
WEAK SHORTWAVE PROGGED TO REACH THE OHIO VALLEY BY DAYBREAK. BACKING
LOW TO MIDLEVEL FLOW DOWNSTREAM OF THIS WAVE RESULTS IN SLIGHT
ISENTROPIC LIFT ACROSS OUR AREA IN THE WEE HRS OF THE MRNG. MOISTURE
IS MARGINAL...BUT IS DEEPEST OVER THE NRN HALF OF THE CWFA...SO I
WILL INTRODUCE A LOW POP THERE BEFORE 12Z. PTYPE EXPECTED TO BE ALL
SNOW...WITH WARM ADVECTION NOT HAVING OCCURRED LONG ENOUGH TO CREATE
A WARM NOSE IN PROFILES OVER THIS AREA. MINS WILL REMAIN SEVERAL
DEGREES BELOW NORMAL. NO WIND CHILL ISSUES ARE EXPECTED...WITH
LOWEST VALUES ALMOST ENTIRELY ABOVE ZERO EVEN ON RIDGES.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 220 AM THURSDAY...A SHORT WAVE DIVING INTO THE EAST COAST
TROUGH CROSSES THE AREA FRIDAY. A WEAK SURFACE WAVE FORMING NEAR THE
GA/SC COAST AND MOVING NORTH ALONG THE COAST IN RESPONSE. THE
GUIDANCE IS IN GOOD AGREEMENT THAT THERE WILL BE CLOUDS FORMING
OUTSIDE OF THE MOUNTAINS...ALONG WITH SOME FLURRIES OR SPRINKLES
OVER NC AND THE EASTERN UPSTATE. DO NOT EXPECT ANY ACCUMULATIONS
BUT CANNOT RULE OUT SOME BRIEFLY HEAVIER THAN FLURRY OR SPRINKLE
PRECIP. EXPECT ANOTHER ROUND OF NW FLOW SNOWFALL ACROSS THE
MOUNTAINS WITH GOOD LOW LEVEL MOISTURE...COLD ADVECTION AND
STRENGTHENING NW FLOW. EXPECT GENERALLY LIGHT ACCUMS IN THE USUAL
HIGH ELEVATION AREAS NEAR THE TN BORDER...BUT CANNOT RULE OUT A
COUPLE OF INCHES BY THE TIME SNOW ENDS LATE FRIDAY NIGHT OR EARLY
SATURDAY MORNING.

EXPECT VERY COLD AND DRY CONDITIONS TO DEVELOP SATURDAY AND SATURDAY
NIGHT AS A SPRAWLING 1040+ ARCTIC HIGH PRESSURE BUILDS INTO THE
REGION. HIGHS SATURDAY AND LOWS SATURDAY NIGHT WILL BE 15-20 DEGREES
BELOW NORMAL. ADVISORY LEVEL WIND CHILL VALUES WILL BE POSSIBLE
ACROSS THE MTNS...ALONG WITH THE POTENTIAL FOR A COLD WAVE.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 405 AM THURSDAY...GUIDANCE COMING INTO BETTER AGREEMENT
REGARDING THE FORECAST OF THE STORM SYSTEM MONDAY AND TUESDAY.

BUT FIRST...SUNDAY WILL BE COLD AND DRY AS ARCTIC HIGH PRESSURE
SETTLES IN OVER THE AREA. HIGHS WILL BE NEAR THE NORMAL LOWS FOR THE
DAY WITH VERY COLD WIND CHILL VALUES ACROSS THE MOUNTAINS IN THE
MORNING.

THE GUIDANCE IS TRENDING TOWARD A MILLER A TYPE SYSTEM...BUT THE
SURFACE LOW IS WELL INLAND WITH AN I-20 TO I-95 TRACK. MOISTURE
SPREADS INTO THE AREA LATE SUNDAY NIGHT AND REMAINS OVER THE AREA
MONDAY AND MONDAY NIGHT AS THE HIGH MOVES EAST ALONG THE AFORE
MENTIONED TRACK. WITH THE VERY COLD AIR IN PLACE AT PRECIP ONSET...
P-TYPE SHOULD START OUT AS SNOW. A WARM NOSE DEVELOPS AS LOW LEVEL
WARM ADVECTION TAKES PLACE MONDAY AS THE LOW MOVES SOUTH OF THE
AREA. THIS WILL CHANGE THE SNOW TO RAIN SOUTH OF I-85...AND PORTIONS
OF THE SW NC MOUNTAINS. THAT SAID...THE SURFACE TEMPS COULD REMAIN
NEAR OR BELOW FREEZING NORTH OF I-85 AND THE WARM NOSE COULD BE
STRONGER AND FARTHER NORTH. THIS WOULD MEAN A TRANSITION TO SLEET
AND FREEZING RAIN...CHANGING MAINLY TO RAIN SOUTH OF I-85. QPF COULD
BE QUITE HIGH CREATING THE POTENTIAL FOR SIGNIFICANT ACCUMULATIONS
OF A WINTRY MIX BEFORE PRECIPITATION TAPERS OFF TUESDAY AS DRIER AIR
MOVES IN BEHIND THE DEPARTING LOW PRESSURE SYSTEM. WILL KEEP THE HWO
MENTION...BUT UNCERTAINTY REMAINS AND THE FORECAST COULD CHANGE
SIGNIFICANTLY AS THE EVENT APPROACHES.

THE REST OF THE MEDIUM RANGE LOOKS RELATIVELY BENIGN. THERE WILL
LIKELY BE A PERIOD OF NW FLOW SNOW ON THE BACK SIDE OF THE SYSTEM
TUESDAY AND TUESDAY NIGHT...TAPERING OFF WEDNESDAY. HIGHS WILL WARM
BACK TO NORMAL LEVELS AS SEASONAL HIGH PRESSURE BUILDS IN.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT AND ELSEWHERE...VFR THRU THE TAF PERIOD. UPPER JET OVER
THE REGION WILL BRING A FEW HIGH CLOUDS THRU TODAY. EARLY ON SOME
MIDLEVEL CLOUDS WILL ALSO BE SEEN OVER THE MTNS...BUT THESE WILL
DISSIPATE THIS MORNING. AS LOW PRESSURE MOVES OFF THE EAST COAST
AND HIGH PRESSURE REPLACES IT FROM THE NW...INITIALLY WESTERLY
WINDS WILL BACK TO SW DURING THE DAYTIME...THEN VEER AROUND TO NE
TONIGHT AT ALL SITES EXCEPT KAVL. A LOWER VFR DECK IS EXPECTED TO
DEVELOP TONIGHT AS WARM ADVECTION DEVELOPS AHEAD OF A SHORTWAVE
MOVING OUT OF THE MID-MISSISSIPPI VALLEY. THERE IS SOME SUPPORT FOR
THE CIG FORMING AT MVFR INSTEAD...PARTICULARLY RIGHT AT THE END OF
THE PERIOD. KAND BEARS THE GREATEST CHANCE OF THIS OCCURRING PRIOR
TO 12Z SO MVFR IS INTRODUCED THERE. HOWEVER...AT OTHER SITES NO
RESTRICTION WILL BE INTRODUCED THIS FAR OUT...GIVEN LOW CONFIDENCE
ON TIMING.

OUTLOOK...A LOW PRESSURE SYSTEM CENTERED NEAR THE MOUTH OF THE
SAVANNAH RIVER MAY SPREAD LOWER MVFR CEILINGS OVER THE PIEDMONT
ON FRIDAY. AN ARCTIC AIR MASS WILL BUILD OVER THE REGION THIS
WEEKEND...RESULTING IN UPSLOPE CLOUDS ALONG THE WEST SIDE OF THE
APPALACHIANS. TEMPERATURES WELL BELOW NORMAL ARE FORECAST FOR
SATURDAY AND SUNDAY.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     MED   79%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     MED   79%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     MED   79%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     MED   79%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY.  COMPLET HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK:

WWW.WEATHER.GOV/GSP/AVIATION

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ033-
     048>052-058-059-062>064.
SC...NONE.

&&

$$
SYNOPSIS...WIMBERLEY
NEAR TERM...WIMBERLEY
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...WIMBERLEY


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