Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 051423
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
923 AM EST THU MAR 5 2015

.SYNOPSIS...
A MOIST COLD FRONT WILL SLOWLY CROSS THE REGION FROM THE NORTHWEST
TODAY...BEFORE COOL AND DRY HIGH PRESSURE BUILDS IN FRIDAY AND
MODIFIES WARMER THROUGH THE WEEKEND. EXPECT A COUPLE OF LOW PRESSURE
SYSTEMS TO DEVELOP OUT OF THE GULF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 AM...SFC FRONT TRYING TO PUSH OFF THE BLUE RIDGE THIS
MORNING. THERE ARE SIGNS ITS FINALLY GOING TO START ITS TREK ACRS
THE FOOTHILLS AND PIEDMONT...AS METARS SHOWING WINDSHIFT TO NW ALONG
I-40. MEANWHILE...TEMPS ARE STILL UP IN THE MID 60S ACRS MOST OF THE
PIEDMONT...WITH GUSTY SW WINDS AND SPOTTY -RA. THE LATEST LAPS CAPE
SHOWS GENERALLY 50-100 J/KG OF SBCAPE ACRS THE UPR SAVANNAH VALLEY
TO THE GREENVILLE AREA. SO CANNOT RULE OUT AN EMBEDDED TSTM ACRS THE
PIEDMONT TODAY...BUT SEVERE THREAT LOOKS VERY LOW. I UPDATED THE
TEMPS/WX TO MATCH UP WITH THE LATEST TIMING OF THE FRONT. STILL NOT
SEEING ANY SUB-FREEZING TEMPS IN ANY OF OBS WITHIN THE CWFA.
HOWEVER...THE TEMPS IN THE MTNS NEAR THE TN LINE HAVE BEEN INCHING
DOWN INTO THE 30S. SO WHILE BACKING OFF TIMING OF PRECIP TYPE
CHANGES IN THE HIGH TERRAIN...STILL EXPECT SOME FREEZING RAIN THEN
SLEET/SNOW MIX FROM THE PEAKS DOWN THIS AFTN. THE VALLEYS BELOW 3500
FT WILL LIKELY STAY RAIN UNTIL LATE AFTN. TIMING OF PRECIP CUTTING
OFF THIS EVENING STILL LOOKS ON TRACK. WITH ALL THAT SAID...STILL
HAVE ENUF PATCHY ICE AND SNOW ACCUMS TO KEEP THE WINTER WX ADV AS IS
WITH THIS UPDATE.

AS OF 600 AM...SFC FRONT OOZING OUT OF THE BLUE RIDGE...AND WITH
RAIN CVRG INCREASING...SFC PRESSURE RISES AND A NE WIND SHOULD
DEVELOP THIS MORNING...INITIALLY ACRS THE NC FTHLS/PIEDMONT. BASED
ON THIS...WARM CONDITIONS SHOULD LINGER ALL MORNING ACRS THE UPSTATE
AND NE GA. IT DOES NOT SEEM TO BE AOB FREEZING ANYWHERE ACRS THE NC
MTNS JUST YET...BUT SLOW COOLING WILL CONTINUE TO EVOLVE FROM THE
TENN BORDER AND HIGHER ELEVATIONS...SLOWLY EXPANDING THE CVRG OF
FREEZING RAIN THROUGH MIDDAY.

AS OF 230 AM...WAVY COLD FRONT PASSED THROUGH KAVL SHORTLY AFTER 06
UTC AND WILL PROBABLY TAKE UNTIL AT LEAST MIDDAY TO CLEAR THE
BALANCE OF THE CWFA. STILL EXPECTING TO SEE WIDESPREAD DEVELOPMENT
OF PCPN IN THE WAKE OF THE FRONT IN A CLASSIC ANAFRONT ORIENTATION.

ADVANCEMENT OF SFC FREEZING LINE STILL UPSTREAM OF THE NC MOUNTAINS
AND ANYTHING MORE THEN LIGHT ICING IN THE HIGHEST ELEVATIONS IS
DOUBTFUL BY DAYBREAK. BUT AS THE MORNING WEARS ON...SUB-FREEZING
SFC TEMPS WILL WORK STEADILY SE INTO THE NC MTNS AND LOWER IN
ELEVATION. WITH MTN FCST SNDGS LINGERING PROMINENT WARM NOSE THROUGH
18Z...ANY WINTRY PCPN OTHER THAN FREEZING RAIN IS DOUBTFUL.

WITH CRITICAL MID-LVL THICKNESS VALUES ENCROACHING THIS AFTERNOON
THE CHANCES FOR MAINLY HIGHER ELEVATIONS TO PICK UP A LIGHT
ACCUMULATION OF SNOW AND/OR SLEET BECOMES MORE LIKELY.

WILL BANK ON THE BULK OF THE PCPN SHIELD TO CLEAR THE MTNS BY
SUNSET AND THE REST OF THE CWFA...MID-EVENING AT THE LATEST.

EXPECT A MORNING/NON-DIURNAL HIGH TEMPS FOR JUST ABOUT EVERYONE
TODAY WITHIN THE LLVL CAA REGIME AND PCPN.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AT 230 AM EST THURSDAY...ON FRIDAY MORNING A BROAD UPPER TROUGH WILL
BE CENTERED OVER THE CENTER OF THE NATION....WHILE AN UPPER LOW WILL
BE OVER NW MEXICO. A PAIR OF SHORTWAVES WILL BE MOVING THROUGH THE
BASE OF THE TROUGH AND ACROSS THE SOUTHERN APPALACHIANS LATER IN THE
DAY. THE TROUGH DEAMPLIFIES SOMEWHAT BY SATURDAY MORNING...RESULTING
IN NEARLY ZONAL FLOW OVER THE SOUTHEAST. A CHANNELED VORT MAX MOVES
THROUGH THE BASE OF THE TROUGH AND ACROSS THE CENTRAL APPALACHIANS
ON SATURDAY NIGHT.

AT THE SURFACE...ON FRIDAY MORNING A STRONG COLD FRONT WILL BE OVER
CENTRAL FL...WITH MOISTURE EXTENDING NORTH TO S GA AND THE SC COAST.
MEANWHILE...HIGH PRESSURE CENTERED OVER THE OH RIVER VALLEY WILL
EXTEND FORM NEW ENGLAND TO THE. BY FRIDAY EVENING THE FRONT IN FL
AND THE RIDGE TO THE N SETTLE SLOWLY S. BY SATURDAY MORNING THE
SURFACE HIGH WILL EXTEND FROM DE TO TX...WHILE THE COLD FRONT WILL
HAVE REACHES S FL.

A COLD FRONT APPROACHES THE SOUTHERN APPALACHIANS FROM THE NW LATE
SATURDAY...CROSSING THE REGION SATURDAY NIGHT. MOISTURE WITH THIS
BOUNDARY IS QUITE LIMITED...AN NOR PRECIPITATION IS EXPECTED WITH
IT. HIGH PRESSURE BUILDS BACK OVER THE AREA FROM IN THE WAKE OF THE
FRONT SATURDAY NIGHT.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 220 AM EST THURSDAY...THE EXT RANGE WILL BEGIN WITH A RATHER
NICE DAY ON SUN. DEVELOPING UPPER CONFLUENCE OFF THE ATL COAST WILL
FORCE A SFC HIGH PRESSURE AREA EAST ACROSS THE FA AND KEEP WINDS
LIGHT AND S/LY. MEANWHILE...MOISTURE LEVELS WILL REMAIN LOW EXCEPT
FOR SOME CI INCREASING FROM THE WEST. MAX TEMPS WILL BE RIGHT AROUND
OR A LITTLE ABOVE NORMAL.

THE FCST BECOMES MORE UNCERTAIN THROUGH THE WORK WEEK AS THE MODELS
HAVE VARYING IDEAS WITH THE SPLIT FLOW AND PLACEMENT OF THE H3 JET
CORE. THE 00Z ECMWF IS MORE AGGRESSIVE WITH BRINGING GOM MOISTURE
OVER THE SE AS IT DEVELOPS CYCLOGENESIS OVER THE NRN GULF IN
RESPONSE TO A BROAD BUT DEEPENING ULVL TROF THRU 12Z TUE. THE GFS ON
THE OTHER HAND...KEEPS DOMINATE HIPRES ANCHORED OVER THE MID ATL AND
A DRY NE/LY FLOW UNDER FLAT RIDGING ALOFT. THE CMC REG SIDES MORE
WITH THE GFS AND THIS WILL BE GIVEN MORE WEIGHT IN THE FCST GRIDS.
THUS...POPS WERE REDUCED MON/TUE TO SLT NORTH AND LOW/END CHANCE
SOUTH.

THERE REMAINS MUCH UNCERTAINTY FOR WED AS THE GFS TAKES THE
LEAD IN DEVELOPING A NORTHWARD MOVING GOM LOW OVER THE DEEP SOUTH
INSTIGATING WIDESPREAD ISENT/WEDGE -SHRA...WHILE THE ECMWF KEEPS A
STATIONARY FRONT AND DEEP MOISTURE FOCUSED SOUTH OF THE FA WITH
MINIMAL PRECIP MAKING IT TO THE SRN ZONES. SO...ONCE AGAIN POPS WERE
LOWERED MOST AREAS WITH NOTHING HIGHER THAN LOW END CHANCE THOUGH
THE DAY. WITH THE NON/ZERO POPS ACROSS THE NC MTNS MON THRU
WED....THERE COULD BE SOME DIURNAL HIGH ELEVATION -SNSH WITH NO
SIGFNT ACCUMS EACH MORNING. TEMPS ARE FCST/D RIGHT AROUND NORMAL
MON/WED...WHICH IS A LITTLE UNDER MOS GUIDANCE DUE TO UNCERTAINTY
WITH THE FLOW AND MOISTURE LEVELS.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT...RAIN WILL CONTINUE TO OVERSPREAD THE TERMINAL MORNING AS
SSW WINDS CONTINUE. GUIDANCE CONSENSUS DOES DIP CIGS TO IFR AROUND
MID-MORNING...BUT NOW DELAYS WIND SHIFT TO NORTHERLY UNTIL MIDDAY AT
THE EARLIEST. STEADY PCPN SHIELD SHOULD ROTATE OFF TO THE EAST BY
EARLY EVENING WITH CLOUDS SCATTERING OUT AT SOME POINT TONIGHT.

ELSEWHERE ACRS THE FA...WIDESPREAD RAIN AND IFR CIGS ARE ON TAP THIS
MORNING WITH FREEZING RAIN AREAS BECOMING MORE NUMEROUS ACRS THE NC
MTNS THRU MIDDAY. IT IS NOW DOUBTFUL THAT KAVL WILL EXPERIENCE ANY
FZRA...PERHAPS JUST A PERIOD OF FROZEN PCPN BY EARLY EVENING.
ANYWAY...PCPN SHIELD WILL MOVE EAST OF THE FA BY THIS EVENING WITH
EVENTUALLY CLEARING OVERNIGHT.

OUTLOOK...VFR CONDITIONS FRIDAY AND 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 6 PM EST THIS EVENING FOR NCZ033-
     048>053-058-059.
SC...NONE.

&&

$$
SYNOPSIS...SBK
NEAR TERM...ARK/CSH
SHORT TERM...JAT
LONG TERM...SBK
AVIATION...CSH



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