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 230704
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
304 AM EDT SAT AUG 23 2014

.SYNOPSIS...
A BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE WILL CONTINUE TO BRING
VERY WARM TEMPERATURES TO MUCH OF THE REGION TODAY. A BACK DOOR COLD
FRONT WILL THEN PUSH INTO THE AREA FROM NORTHEAST USHERING IN COOLER
TEMPERATURES STARTING SUNDAY. TEMPERATURES WILL GRADUALLY RETURN TO
NORMAL THROUGH NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
FOR THE REMAINDER OF THE PRE-DAWN HOURS...EXPECT THE REMNANTS OF AN
MCS TO RAIN OUT ACROSS THE NRN MOUNTAINS AND NRN FOOTHILLS. AFTER
09Z OR SO...EXPECT EXTENSIVE CONVECTIVE DEBRIS CLOUDS...WITH PERHAPS
SOME FOG DEVELOPING ON THE ERN SIDE OF METRO CHARLOTTE WHERE IT
RAINED FRIDAY EVENING...IF THE SKY CAN CLEAR OUT A BIT.

OVER THE NEXT 24 HOURS...THE UPPER PATTERN WILL CONTINUE TO AMPLIFY
WITH THE CENTER OF AN UPPER ANTICYCLONE OVER THE ARKLATEX AND MS
DELTA REGIONS...AND A POSITIVELY TILTED UPPER TROF OFF THE MID
ATLANTIC COAST. A FAIRLY SUBSTANTIAL SHORT WAVE DROPPING DOWN INTO
THE TROF IS EXPECTED TO DRIVE A BACK DOOR COLD FRONT INTO THE AREA
TONIGHT. BEFORE THAT HAPPENS...ONE MORE HOT DAY ACROSS MOST OF THE
REGION WITH PERHAPS THE EXCEPTION OF THE NW PIEDMONT. MORE EXTENSIVE
CLOUDINESS MIGHT KEEP HIGH TEMPS A DEGREE OR TWO BELOW FRIDAYS
HIGHS. THE MODELS SUGGEST THAT THE BALANCE OF THE DAY WILL BE
DRY...PERHAPS FOR LACK OF A TRIGGER BEFORE THE COLD FRONT ARRIVES
FROM THE NE LATE IN THE DAY. AN MVC OR SHORT WAVE DROPS DOWN FROM
THE N BUT SHOULD REMAIN TO THE WEST THIS AFTERNOON. THIS MIGHT
SUPPORT SOME CONVECTION OVER THE MTNS...SO A CHANCE POP WAS KEPT
NEAR THE TN BORDER...BUT NE GEORGIA AND UPSTATE SC WERE KEPT IN THE
SLIGHT CHANCE RANGE UNTIL LATE AFTERNOON WHEN THE POP RAMPS UP TO
CHANCE AHEAD OF THE FRONT. THE TIMING OF THE FRONTAL PASSAGE IS HARD
TO PIN DOWN BECAUSE THE WIND SHIFT MIGHT BE A SUBTLE CHANGE FROM N
TO NE...BUT EXPECT THIS TO MAINLY HAPPEN AFTER SUNSET. A BAND OF LOW
LEVEL MOISTURE CONVERGENCE WILL SUPPORT KEEPING A CHANCE OF PRECIP
ACROSS THE ENTIRE AREA TONIGHT...WITH THE HIGHEST CHANCES NEAR THE
NC BLUE RIDGE AS AN EASTERLY UPSLOPE FLOW DEVELOPS. TEMPS WILL
REMAIN MILD WITH EXTENSIVE CLOUD COVER. CANNOT RULE OUT A FEW SEVERE
STORMS WHICH MAKES SENSE WITH THE EXPECTED AIR MASS CHANGE...BUT THE
POTENTIAL FOR FLASH FLOODING SHOULD ALSO BE HIGHER THAN PREVIOUS
DAYS E OF THE MTNS WITH THE INCREASED LOW LEVEL FORCING AND EASTERLY
UPSLOPE PERHAPS TRAPPING SOME CONVECTION NEAR THE BLUE RIDGE WHILE
WE MAINTAIN HIGH PW.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 245 AM SATURDAY...ON SUNDAY...THE WEDGE FRONT WILL REACH
ACROSS THE DEEP SOUTH BY SUNRISE. RIDGING HIGH PRESSURE WILL REMAIN
ACROSS THE FORECAST AREA ON SUNDAY. THE FORECAST WILL FEATURE
ABUNDANT CLOUD COVER AND STEADY ENE WINDS. POPS WILL REMAIN IN THE
CHC RANGE ACROSS THE MTNS AND NE GA...HIGHLIGHTING LINGERING WEAK
INSTABILITY AND UPSLOPE FLOW. ELSEWHERE...CONDITIONS SHOULD
GENERALLY REMAIN DRY. HIGH TEMPERATURES ARE FORECAST TO RANGE IN THE
70S ACROSS THE HIGH TERRAIN...LOW TO MID 80S ELSEWHERE.

MONDAY...SHORT RANGE MODELS SHOW DEEP DRY AIR ADVECTING SW ACROSS
THE FORECAST AREA. IN ADDITION...THE CENTER OF H5 RIDGE IS EXPECTED
LIFT NORTH ACROSS THE MID MISSISSIPPI RIVER VALLEY...WITH THE
EASTERN EDGE OF THE RIDGE ACROSS THE SOUTHERN APPALACHIANS. GFS
FORECAST SOUNDINGS APPEAR QUITE DRY...PW LESS THAN .75 AND WARM
TEMPERATURES ABOVE H8. SCHC POPS WILL BE LIMITED TO THE WESTERN NC
MTNS...NO MENTIONABLE POPS ACROSS THE REMAINDER OF THE CWA.
TEMPERATURES SHOULD RANGE CLOSELY TO SUNDAY/S VALUES.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...TUESDAY AND WEDNESDAY...SFC RIDGING WILL
CONTINUE ACROSS THE CWA...BUT TRENDING WEAKER WITH LIGHTER WINDS.
THE CENTER OF H5 590DM RIDGE WILL LIKELY SHIFT ACROSS THE SOUTHEAST.
TEMPERATURES SHOULD WARM TO NEAR NORMAL BY WEDNESDAY...AIDED BY
WARMING LLVL THICKNESSES AND INSOLATION. FORECAST SOUNDINGS INDICATE
THAT CONDITIONS WILL REMAIN DRY AND STABLE...SUPPORTING SINGLE DIGIT
POPS. THURSDAY AND FRIDAY...TROPICAL LOW IS EXPECTED TO TRACK OFF
THE CAROLINA COAST. THE GFS INDICATES THAT A COLD FRONT WILL SWEEP
ACROSS THE REGION ON FRIDAY...ACCOMPANIED BY A LONGWAVE TROF. THE
ECMWF KEEPS THE REGION UNDER MID LEVEL RIDGING AND SFC HIGH
PRESSURE...KEEPING ANY SFC BOUNDARIES WELL NORTH OF THE REGION.
NATIONAL GUIDANCE FAVORS THE ECMWF SOLUTION. I WILL INDICATE
SEASONABLE TEMPS WITH DIURNAL CHC POPS.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...KEPT CONDITIONS VFR THROUGH THE TAF PERIOD...BUT THERE IS
SOME CHANCE OF A FOG RESTRICTION DEVELOPING IN THE PRE-DAWN HOURS
DUE TO CONVECTION THIS PAST EVENING IN CLOSE PROXIMITY. LEFT FOG OUT
OF THE TAF BECAUSE RAIN DID NOT FALL OVER THE AIRFIELD...BUT THERE
WILL BE SOME FOG AROUND METRO CLT BY DAYBREAK. WIND SHOULD COME
AROUND TO LIGHT N OVERNIGHT...AND LIGHT NE ON SATURDAY. THINK FOR
THE MOST PART THE DAY WILL BE QUIET SIMILAR TO FRIDAY...WITH
CONVECTION NOT DEVELOPING UNTIL THE EVE AS A BACK DOOR COLD FRONT
APPROACHES. HANDLED THIS WITH A PROB30 TO ENCOMPASS A LARGER TIME
PERIOD. THIS WILL BE CHANGED TO A TEMPO FOR TSRA WHEN TIMING OF
STORMS WITH THE FRONTAL PASSAGE BECOMES CLEARER.

ELSEWHERE...SIMILAR TO KCLT. EXPECT WEAKENING MCS REMNANTS TO AFFECT
KHKY THROUGH THE PRE-DAWN HOURS...BUT PROBABLY STILL PREVAILING VFR.
THREW IN A VICINITY SHOWER AT KAVL AS WELL. SPEAKING OF KAVL...THE
GUIDANCE CONTINUES TO FCST FOG DEVELOPMENT THAT HAS NOT HAPPENED FOR
SEVERAL DAYS...SO THE TAF ONLY INCLUDES A TEMPO FOR MVFR VISIBILITY.
OTHERWISE...VFR EXPECTED THRU THE PERIOD. WINDS SHOULD BE LIGHT N OR
NE THROUGH SUNRISE...AND THEN BECOMING MORE NE LATE IN THE DAY.
ANOTHER ROUND OF SCT CONVECTION POSSIBLE LATER IN THE DAY BUT THIS
WAS PUSHED OFF UNTIL LATE AFTERNOON AND EVENING BASED ON THE NAM.

OUTLOOK...A BACKDOOR COLD FRONT WILL SAG INTO THE REGION SAT NITE
THROUGH SUN...WITH CHANCES OF RESTRICTIONS INCREASING AT KHKY AND
KAVL THROUGH SUNDAY. A MORE DIURNAL PATTERN OF EARLY MORNING LOW
CLOUDS/FOG AND ISOLD AFTN TSTMS MAY RETURN EARLY NEXT WEEK...WITH
STEADY DRYING.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-07Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  95%
KGSP       HIGH  91%     HIGH  97%     HIGH 100%     HIGH 100%
KAVL       MED   74%     HIGH  92%     HIGH 100%     HIGH  88%
KHKY       HIGH  91%     HIGH  97%     HIGH 100%     HIGH  97%
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...NONE.
SC...NONE.

&&

$$
SYNOPSIS...JOH/NED
NEAR TERM...PM
SHORT TERM...NED
LONG TERM...NED
AVIATION...PM






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