Area Forecast Discussion
Issued by NWS Greer, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 062115
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
515 PM EDT FRI MAY 6 2016

.SYNOPSIS...
A DEEP AREA OF UPPER LEVEL LOW PRESSURE WILL BEGIN TO MOVE OFF THE
EAST COAST TONIGHT. A FRONTAL BOUNDARY IS EXPECTED TO STALL JUST
TO OUR NORTH LATER IN THE WEEKEND. HIGH PRESSURE OFF THE SOUTHEAST
COAST EXPANDS INTO EARLY NEXT WEEK. WARM SOUTHERLY FLOW RETURNS
AT THAT TIME...FOLLOWED BY ANOTHER DISTURBANCE BRINGING CHANCES
OF SHOWERS TUESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
500 PM EDT UPDATE...MADE SOME MINOR TWEAKS TO THE SKY/POP GRIDS WITH
DRIER AIR WORKING IN ASSOCIATED WITH DNVA IN ULVL TROF. GUSTY CONDS
WILL CONTINUE ACROSS THE MTNS AND NRN FHILLS TILL SUNSET WITH WINDS
BACKING DOWN A COUPLE HRS SOONER ELSEWHERE. TEMPS AND TD/S ARE IN
GOOD SHAPE.

AS OF 200 PM...UPPER TROUGH REMAINS OVER THE EASTERN SEABOARD...WITH
EMBEDDED CLOSED LOW OVER THE DELMARVA PENINSULA. NAM/GFS RESOLVE
MESOSCALE LOBES OF VORTICITY SWINGING SOUTHWARD THRU THE CWFA
THIS AFTN. SPC MESOANALYSIS ALREADY SHOWS UPWARDS OF 250 J/KG
SBCAPE PRESENT OVER THE ERN HALF OF THE CWFA WHERE UPPER LEVELS
ARE COOLEST UNDER THE TROUGH...LOWER BUT NONZERO VALUES BEING
PRESENT ELSEWHERE.  STRATOCU LINGER OVER THE MTNS AND A FEW SHRA
ARE BEGINNING TO DEVELOP WITHIN THEM...LIKELY IN RESPONSE TO
THE DPVA ALOFT. PER CONSENSUS OF SHORT RANGE GUIDANCE...FURTHER
DESTABILIZATION AND SHRA ARE EXPECTED OVER MAINLY THE ERN HALF OF
THE AREA...TAPERING OFF DIURNALLY NEAR SUNSET. INSTABILITY LOOKS
TOO MARGINAL TO INCLUDE THUNDER IN FCST...BUT PERHAPS ONE OR TWO
LIGHTNING STRIKES WILL OCCUR. GUSTY WINDS WILL CONTINUE ACRS THE
AREA GIVEN TIGHT GRADIENT FLOW AROUND THE SFC/UPPER LOW.

A COUPLE MORE VORT LOBES WILL CROSS THE AREA TONIGHT...THOUGH
WITHOUT MUCH MOISTURE AND WITH CONTINUING DOWNSLOPING WINDS ACRS
MOST OF THE CWFA...NO QPF WILL BE GENERATED. THE LIGHT WIND SHOULD
KEEP LOW TEMPS FROM DIPPING TOO LOW...ENDING UP CLOSE TO FRI MRNG
READINGS. DURING THE DAY SATURDAY...THE OMEGA BLOCK OVER THE CONUS
WILL BREAK DOWN AS A POLAR TROUGH DIGS INTO THE GREAT LAKES. THE
PROGRESSION OF THE UPPER PATTERN LEADS TO HEIGHT RISES OVER THE
SOUTHEAST...AND THE MIDLEVELS WARM ACCORDINGLY. THIS WILL INHIBIT
DEEP CONVECTION. AS WINDS BACK TO A MORE WESTERLY DIRECTION...THEY
INITIATE WAA WHICH WILL BRING TEMPERATURES BACK TO MORE SEASONABLE
VALUES. GIVEN THE MORE TYPICAL SPRINGTIME PATTERN...I APPLIED A
SHARE OF BIAS CORRECTED TEMP DATA TO THE MAX TEMP FCST. THIS GIVES
ID 70S IN MTN VALLEYS AND THE NW NC PIEDMONT...AND NEAR 80 OVER
MOST OF THE UPSTATE AND NE GA.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 215 PM FRIDAY...WEAK SHORT WAVES CROSS THE AREA SUNDAY IN THE
NW FLOW DEVELOPING OVER THE AREA BETWEEN THE DEPARTING UPPER LOW AND
RIDGING OVER THE CENTRAL CONUS. A BACK DOOR COLD FRONT DROPS TOWARD
THE AREA SATURDAY NIGHT AND STALLS NEAR THE VA/NC BORDER ON SUNDAY.
GUIDANCE IS IN GOOD AGREEMENT WITH THE BEST PRECIP CHANCES
DEVELOPING NORTH OF THE FRONT. STILL...THERE COULD BE SOME ISOLATED
CONVECTION ACROSS THE NORTHERN PORTIONS OF THE TN BORDER COUNTIES
WHERE BEST MOISTURE AND FORCING EXIST. DESPITE MOISTURE POOLING
SOUTH OF THE FRONT OVER THE NC FOOTHILLS AND PIEDMONT...INSTABILITY
REMAINS LIMITED WITH A LOW LEVEL WARM NOSE LEADING TO VERY HIGH LFC
LEVELS. THE COLD FRONT MOVES BACK NORTH AS A WARM FRONT ON SUNDAY
ALLOWING A LOW LEVEL SOUTHWESTERLY FLOW TO DEVELOP. SOME WEAK SHORT
WAVE ENERGY UNDERCUTS THE RIDGE MOVING IN FROM THE WEST AND MOVES
ACROSS THE AREA MONDAY. DESPITE THE LOW LEVEL FLOW...MOISTURE
REMAINS LIMITED LEADING TO LIMITED INSTABILITY. BETTER MOISTURE AND
FORCING REMAIN ACROSS THE NORTHERN MOUNTAINS AND DIFFERENTIAL
HEATING COULD HELP KICK OFF SOME ISOLATED DIURNAL CONVECTION THERE.
OTHERWISE...A DRY FORECAST CONTINUES FOR THE REST OF THE CWFA. TEMPS
WILL REMAIN NEARLY STEADY AROUND 10 DEGREES ABOVE NORMAL BOTH DAYS.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 215 PM FRIDAY...WARM SECTOR WEATHER ACROSS THE REGION LOOKS
LIKE IT WILL CONTINUE THROUGH TUESDAY FEATURING MORE IN THE WAY OF
ABOVE NORMAL TEMPERATURES AND A SMALL INFLUX IN RETURN FLOW
MOISTURE.  THE INHERITED FCST FOR TUESDAY REMAINS ON TRACK FEATURING
DIURNAL MAINLY MOUNTAIN TSTM CHANCES.  THE PATTERN FOR WEDNESDAY
BECOMES A LITTLE FLATTER...MORE MOIST AND LESS SUPPRESSED.  WARM
TEMPERATURES SHOULD CONTINUE WITH WHAT SHOULD BE BETTER CHANCES AND
CVRG OF DIURNAL THUNDERSTORMS.

FOR THE LATTER HALF OF THE WEEK...THE TREND IS FOR THE PATTERN TO
GET A TAD WAVY AND HEIGHTS ATOP THE SE CONUS WILL START TO FALL.
WARM PERSISTENCE MAXIMUM TEMPERATURES WILL BE FCST FOR THURSDAY. IT
REMAINS TO BE SEEN IF S/WV CAN BE TIMED TO TRANSLATE DOWNSTREAM OF
THE REGION TO ACTUALLY RESULT IN A DIURNAL DEEP CONVECTIVE MINIMA AS
PER THE 06/12 UTC OP GFS RUN. THE NEW DAY 7 MAX TEMPERATURES ARE
PROGGED TO BE ABOUT A CATEGORY LESS WARM THAN THURSDAY.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...EXPECTING VFR TO PREVAIL THRU SATURDAY
MRNG...WITH EVEN THE ISOLD-SCTD SHRA THIS AFTN APPEARING UNLIKELY
TO PRODUCE RESTRICTIONS SAVE PERHAPS FOR BRIEF MVFR VSBY. THESE
SHOWERS ARE DEVELOPING IN THE UNSTABLE ENVIRONMENT FOSTERED BY
AN UPPER LOW OVER THE MID-ATLANTIC COAST...WHICH WILL DRIFT OFF
TO THE EAST TONIGHT. A POCKET OF MIDLEVEL MOISTURE MOVING THROUGH
MAY BRING A PERIOD OF VFR CIGS OVERNIGHT. THE MAIN IMPACT WEATHER
WILL BE WINDS...WHICH REMAIN RATHER GUSTY THIS AFTN WITHIN THE
GRADIENT AROUND THE SFC LOW TO THE NE OF THE REGION. THIS GRADIENT
WILL BE ALMOST AS STRONG SATURDAY...SO WINDS ARE EXPECTED TO PICK
UP QUICKLY AFTER DAYBREAK AND GUST ONCE AGAIN...SIMILAR TO TODAY.


OUTLOOK...DRYING WILL CONTINUE INTO SATURDAY. A COLD FRONT WILL
APPROACH FROM THE NORTH SUNDAY...WITH ASSOCIATED PRECIPITATION
LIKELY REMAINING NORTH OF ALL THE TERMINALS BEFORE THE FRONT
STALLS. WARMING CONDITIONS WITH A RETURN TO SW FLOW ARE EXPECTED
THROUGH EARLY NEXT WEEK.

CONFIDENCE TABLE...

            21-03Z        03-09Z        09-15Z        15-18Z
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...WIMBERLEY/SBK
SHORT TERM...RWH
LONG TERM...CSH
AVIATION...WIMBERLEY



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