« 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

619
FXUS62 KGSP 051438
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
938 AM EST FRI FEB 5 2016

.SYNOPSIS...
A COLD FRONT WILL PUSH OFF THE CAROLINA COAST TODAY. LOW PRESSURE IS
EXPECTED TO FORM ON SUNDAY WELL OFFSHORE ALONG THIS FRONT...BRINGING
SHOWERS TO THE LOW COUNTRY. ANOTHER COLD FRONT ARRIVES FROM THE
WEST MONDAY...BRINGING FRIGID CANADIAN AIR INTO THE AREA WHICH
WILL LAST THROUGH MIDWEEK. SNOW SHOWERS WILL BE QUITE POSSIBLE IN
THE MOUNTAINS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM...NOT REALLY SEEING THE AMOUNT OF WIND THAT WE THOUGHT
WOULD LINGER ACROSS THE NRN MTNS AND BLUE RIDGE. WHILE YOU MIGHT
STILL CALL IT A WINDY MORNING...IT DOES NOT REALLY MEET WIND
ADVISORY CRITERIA. THUS...THE WIND ADVISORY WILL BE DROPPED WITH THE
MORNING UPDATE. THE OTHER DEFICIENCY APPEARS TO BE WITH THE
DEWPOINT. STRONG MIXING WAS PULLING DOWN MUCH DRIER AIR ALOFT...
RESULTING IN THE DEWPOINT BEING ABOUT FIVE DEGREES LOWER THAN FCST.
WILL MAKE A DOWNWARD ADJUSTMENT TO RH FOR THE REST OF THE DAY.
OTHERWISE...EXPECT A SUNNY DAY WITH SEASONALLY COOL TEMPS AS HIGH
PRESSURE BUILDS IN FROM THE WEST.

PRESSURE GRADIENT RELAXES QUICKLY THIS AFTERNOON OR EVENING AS HIGH
PRESSURE BUILDS IN THRU THE NITE. SKIES START OUT CLEAR...BUT SHUD
SEE INCREASING CIRRUS THRU THE NITE. THIS WILL KEEP THE AREA FROM
SEEING PERFECT RADIATIONAL COOLING CONDITIONS. HOWEVER...STILL
EXPECT LOWS TO BE AROUND 5 DEGREES BELOW NORMAL.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 AM FRI...UPPER HEIGHTS WILL BEGIN TO FALL SATURDAY
MORNING AS PHASED TROUGHS MOVE INTO THE EASTERN CONUS. MODEL
CONSENSUS CONTINUES TO BE THAT THE SRN STREAM SHORTWAVE WILL CUT
OFF SATURDAY NIGHT OVER THE SRN END OF THE APPALACHIANS...RAPIDLY
SPINNING UP A SFC LOW JUST OFF THE SOUTH ATLANTIC COAST. A SMALL
NUMBER OF SREF MEMBERS DO SPREAD SOME OF THE ASSOCIATED PRECIP
INTO THE SRN NC AND SC PIEDMONT...BUT THE REST OF THE CONSULTED
GUIDANCE KEEPS IT SOUTH AND EAST OF OUR CWFA. THESE ARE OUTLIERS
FROM THE OVERALL MODEL ENVELOPE...SO IT SEEMS BEST TO KEEP POPS
BELOW MENTIONABLE VALUES. THESE MINUSCULE CHANCES WILL DECLINE
SUNDAY AS THE LOW DEPARTS THE COAST. HEIGHTS RISE IN THE WAKE
OF THE SYSTEM ONLY BRIEFLY...WITH A MORE SUBSTANTIAL CUTOFF LOW
DIVING INTO THE MISSISSIPPI VALLEY SUNDAY AFTERNOON AND NIGHT. UPPER
DIVERGENCE AND DPVA WILL PROVIDE INCREASING LIFT OVER THE AREA BY
EARLY MONDAY MORNING...AND PRECIP CHANCES INCREASE FROM THE WEST
BY THIS TIME. SFC TEMPS WILL BE COLD ENOUGH TO EXPECT ANY PRECIP
TO FALL AS SNOW...THOUGH CHANCES DO NOT EXPAND BEYOND THE MTNS
BEFORE DAYBREAK.

TEMPS WILL BE ABOUT A CATEGORY BELOW NORMAL SATURDAY AND SATURDAY
NIGHT...TICKING UP SLIGHTLY SUNDAY UNDER GREATER THICKNESSES
BETWEEN THE TROUGHS...AND RETURNING TO NORMAL.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 315 AM FRI...DEEP UPPER TROUGH WILL SETTLE OVER THE EASTERN
CONUS MONDAY...REACHING ITS GREATEST EXTENT TUESDAY MORNING BEFORE
SLOWLY LIFTING TOWARD THE NORTHEAST MID-WEEK. VORT LOBES ROTATING
AROUND THE CLOSED CIRCULATION EMBEDDED WITHIN WILL BRING BOUTS
OF QG FORCING EACH DAY FROM MONDAY TO WEDNESDAY. ARRIVING ARCTIC
AIR WILL CAUSE TEMPS TO TREND DOWNWARD EACH DAY MON-WED...MAXES
AS MUCH AS 15-18 DEGREES BELOW NORMAL.

THE MOST ROBUST BOUT WILL OCCUR DURING THE DAY MONDAY...CONCURRENT
WITH STRONG 700-500MB LAPSE RATES AND DEEP MOISTURE. SOLID
CHANCE TO LIKELY POPS ARE WARRANTED ACROSS THE CWFA MONDAY AFTN
ACCORDINGLY. TEMPS WILL TOP OUT A FEW DEGREES BELOW CLIMO...BUT
NOT EXCEPTIONALLY COLD AT THE SFC. IN THE MTNS PRECIP WILL START
AND END AS SNOW...PERHAPS WITH ENOUGH WARMING DURING THE DAY TO
PERMIT RAIN FOR A TIME. EAST OF THE MTNS...IT WILL BE A LITTLE MORE
TRICKY. PARTIAL THICKNESS P-TYPE TECHNIQUE BASED ON EITHER GFS OR
EC SUGGESTS A TRANSITION FROM RAIN...TO RAIN-SNOW...TO ALL SNOW
OVER THE COURSE OF THE DAY. THE EXPECTED SFC TEMPS HOWEVER DO NOT
SUGGEST MUCH SNOW UNTIL LATE AFTN. THERE IS POTENTIAL FOR WET-BULB
EFFECTS TO SPEED THE TRANSITION EARLIER IN THE DAY...AND THIS IS
ESPECIALLY LIKELY IF CONVECTIVE SHOWERS DO DEVELOP. FOR NOW...WE
WILL ONLY ADVERTISE ACCUMULATING SNOW IN THE MTNS/FOOTHILLS...WHERE
TEMPS ARE MOST CONDUCIVE AND DOWNSLOPING WILL HAVE LESSER IMPACT.

CHANCES TAPER OFF FAIRLY QUICKLY MON EVENING BEHIND THE FIRST SHOT
OF FORCING. THE SUBSEQUENT LOBES TUE AND WED DO NOT BEAR QUITE AS
MUCH POTENTIAL TO PRODUCE SHOWERS EAST OF THE MTNS...MOSTLY DUE
TO A LACK OF MOISTURE AND WEAKER LAPSE RATES. HOWEVER...WITH NW
FLOW BEING AIDED BY THE QG FORCING...THE CHANCE FOR SNOW ALONG
THE TENN BORDER WILL PERSIST MORE OR LESS CONSTANTLY INTO THU.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...PRECIP HAS MOVED EAST AND SKIES ARE CLEARING BEHIND THE
DEPARTING SHORT WAVE. EXPECT CLEAR SKIES FOR THE REST OF THE DAY
WITH GUSTY NLY WINDS. WINDS DIMINISH THIS EVENING AND TURN NELY
OVERNIGHT. EXPECT INCREASING CIRRUS THIS EVENING AND OVERNIGHT.

ELSEWHERE...SIMILAR CONDITIONS TO KCLT...BUT WITH STRONGER GUSTY
WINDS AT KAVL AND LIGHTER MORE NWLY WINDS AT KAND.

OUTLOOK...LARGE HIGH PRESSURE WILL SLOWLY BUILD ACROSS THE REGION
THROUGH THE WEEKEND WITH UNRESTRICTED CONDITIONS EXPECTED. A STRONG
UPPER AIR DISTURBANCE COULD BRING ENOUGH MOISTURE TO WRING OUT A FEW
RAIN OR SNOW SHOWERS ON MONDAY.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-12Z
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%     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 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...NONE.
SC...NONE.

&&

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



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