Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 291726
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
126 PM EDT WED JUL 29 2015

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST OVER THE REGION TODAY...WITH TEMPERATURES
REMAINING ABOVE NORMAL. A WEAK COLD FRONT WILL APPROACH THE AREA
FROM THE NORTHWEST ON THURSDAY AND SETTLE SOUTHEAST OF THE REGION ON
FRIDAY. THE FRONT AND ASSOCIATED DEEPER MOISTURE WILL LIKELY REMAIN
CONFINED TOWARD THE SOUTHEAST COASTLINE THROUGH THE WEEKEND...WITH
SLIGHTLY COOLER TEMPERATURES OVER THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA. LOW LEVEL MOISTURE WILL SLOWLY RETURN EARLY NEXT
WEEK.

&&

.NEAR TERM /THROUGH THURSDAY/...
OF 1245 PM...ADJUSTED THE POPS BASED ON LATEST RADAR TRENDS. SCT
SHOWERS DEVELOPING MANY AREAS. SHOULD START TO SEE SOME LIGHTNING
SOON. SLOW MOVING CELLS WILL PRODUCE LOCALLY HEAVY RAIN. OTHER
PARAMETERS ON TRACK.

AS OF 1000 AM...RADAR CURRENTLY CLEAR OF ECHOES SO ADJUSTED NEAR
TERM POPS DOWNWARD FOR THIS MORNING. CAMS STILL SHOW CONVECTION
DEVELOPING EARLY THIS AFTERNOON ALONG THE BLUE RIDGE WITH OUTFLOWS
TRIGGERING ADDITIONAL DEVELOPMENT ACROSS THE FOOTHILLS/PIEDMONT DURING
THE AFTERNOON HOURS. TWEAKED THE POP TRENDS TO BETTER DEPICT THIS
SCENARIO. WITH SLOW MOVEMENT OF THUNDERSTORMS...LOCALLY HEAVY RAIN
IS POSSIBLE. ALSO...CAN`T RULE OUT A COUPLE ISOLATED MOIST
MICROBURSTS. STILL EXPECT MAX TEMPS TO TOP OUT IN THE LOWER TO MID
90S OUTSIDE THE MOUNTAINS WITH MID 80S MOUNTAIN VALLEYS.

AS OF 635 AM...I WILL UPDATE THE FORECAST TO FINE TUNE FOG MENTION
TO LATEST OBSERVATIONS. OTHERWISE...IT APPEAR THAT CLOUD COVER WILL
INCREASE STEADILY WITH THE FORMATION OF STRATUS OVER THE NEXT TWO
HOURS. I WILL UPDATE THE SKY FORECAST.

AS OF 325 AM...RECENT WATER VAPOR IMAGES INDICATED A LARGE MCS AND
VORT MAX TRACKING SE ACROSS THE CORN BELT. IN ADDITION...ANOTHER
DISTURBANCE WILL TRACKING ACROSS THE AL/TN STATE LINE. THESE
FEATURES SHOULD CONTINUE TO MOVE SSE...AROUND A LARGE MID LEVEL HIGH
CENTERED OVER THE SOUTHERN PLAINS. BASED ON THE MID LEVEL PATTERN
AND NEAR TERM GUIDANCE...THE SYSTEM TRACKING FROM THE NW MAY REACH
THE SOUTHERN APPALACHIAN REGION THIS EVENING. THE ENVIRONMENT ACROSS
THE WESTERN CAROLINAS AND NE GA WILL CHANGE LITTLE FROM TUESDAY
AFTERNOON. FORECAST SOUNDING INDICATE THAT CAPES SHOULD PEAK BETWEEN
1500-2000 J/KG...SHEAR WILL REMAIN WEAK...AND LLVL DEWPOINTS WILL
REMAIN IN THE U60S TO L70S. CAMS AND OPERATIONAL MODELS INDICATE
THAT CONVECTION WILL INITIATE ACROSS THE EAST FACING SLOPES EARLY
THIS AFTERNOON...THEN TRACK EAST. ADDITIONAL SHRA AND TSRA MAY
DEVELOP DURING THE EVENING HOURS AS THE MID LEVEL FEATURE APPROACHES
FROM THE NW. SPC DY 1 OUTLOOK KEEP THE CWA WITHIN THE GENERAL TSRA.
WE WILL HIGHLIGHT LIGHTNING...HEAVY DOWNPOURS...AND GUSTY WINDS IN
THE HWO. HIGH TEMPERATURES SHOULD RANGE WITHIN 1 TO 2 DEGREES FROM
VALUES OBSERVED YESTERDAY.

TONIGHT...CONVECTION SHOULD GENERALLY DISSIPATE AFTER MIDNIGHT. IT
APPEARS THAT WAVES OF HIGH/DEBRIS CLOUDS WILL REMAIN ACROSS THE
REGION THROUGH THE OVERNIGHT HOURS. I WILL FOLLOW THE TREND OF THE
PAST SEVERAL NIGHTS...INDICATING PARTLY CLOUDY SKY...LIGHT TO CALM
WIND...AND PATCHES OF FOG. LOWS ARE FORECAST TO RANGE FROM THE U60S
WITHIN THE MTN VALLEYS TO L70S EAST.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 300 AM EDT WEDNESDAY...THE BROAD RIDGE OF HIGH PRESSURE OVER
THE SOUTHERN CONUS EARLY THURSDAY WILL CONTINUE TO RETROGRADE
WESTWARD THROUGH THE SHORT TERM PERIOD. UPPER HEIGHTS WILL BEGIN TO
FALL OVER THE EAST ON THURSDAY...ALLOWING A COLD FRONT TO ARRIVE
FROM THE NORTHWEST. DEEPER MOISTURE ALONG THE IMMEDIATE FRONTAL ZONE
WILL SLIDE INTO THE NC MTNS FROM 12Z TO 18Z...WITH THE BOUNDARY
ENCOUNTERING ADDITIONAL INSTABILITY AND LOW LEVEL DCAPE EAST OF THE
MOUTAINS THROUGH THURSDAY AFTERNOON AND EVENING. HOWEVER...FRONTAL
ZONE FORCING WILL BATTLE DRIER AIR ARRIVING FROM THE NW TO LIMIT
COVERAGE SOMEWHAT. WILL STILL FEATURE SOLID CHANCE POPS FOR
CONVECTION GIVEN THE STEEPENING LAPSE RATES ALOFT. EXPECT ONE MORE
DAY OF ABOVE CLIMO MAXES AHEAD OF THE FRONTAL ZONE.

A SHARPENING UPPER TROUGH WILL THEN DEVELOP SWD FROM A HUDSON BAY
CANADA CYCLONE INTO THE SOUTHEAST U.S. BY FRIDAY. MUCH DRIER AIR
WILL ALSO START TO ARRIVE FROM THE N AS SFC HIGH PRESSURE MOVES EAST
FROM THE LOWER OH VALLEY. TEMPERATURES WILL FALL CLOSER TO
CLIMO...WITH ISOLD SHOWER CHANCES MAINLY OVER THE SOUTHEAST PART OF
THE AREA.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 AM EDT WEDNESDAY...A WESTERN RIDGE/EASTERN TROUGH PATTERN
WILL REMAIN IN PLACE DURING THE SATURDAY THROUGH TUESDAY PERIOD.
MOISTURE WILL REMAIN FOCUSED MAINLY ALONG THE FRONT TO THE
SOUTHEAST...WITH THE NUMERICAL MODELS TRENDING TOWARD CONFINING THE
DEEPEST MOISTURE TO THE IMMEDIATE SOUTHEAST COASTLINE THROUGH THE
WEEKEND. A WEAKLY REINFORCING COLD FRONT WILL APPROACH FROM THE NW
SATURDAY NIGHT...BUT LIKELY STALL OR DISSIPATE JUST AS IT REACHES
THE FORECAST AREA. MEANWHILE...NUMEROUS SHORTWAVES WILL MOVE THROUGH
THE MEAN TROUGH DURING THE PERIOD. THESE WILL BE HARD TO TIME AND
GENERALLY HAVE LIMITED MOISTURE TO WORK WITH. WILL FEATURE A MOSTLY
DIURNAL TREND ON ANY LOW END AFTN/EVENING POPS EACH DAY. STEEP 850
TO 500 MB LAPSE RATES LINGER OVER THE AREA UNDER THE TROUGH
AXIS...BUT WITH SURPRISINGLY LITTLE CAPE KEEPING ANY CONVECTION
FAIRLY SHALLOW. TEMPERATURES WILL BE COOLER THROUGH THE
WEEKEND BEFORE SLOWLY REBOUNDING EARLY NEXT WEEK.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...CONVECTIVE CONCERNS THIS AFTERNOON INTO THE EVENING ARE
THE MAIN CONCERN. SCT SHRA/TSRA DEVELOPING WEST/NORTH OF THE
AIRFIELD BUT MOVING ONLY VERY SLOWLY SE. CAMS INDICATE THAT CELLS
WILL CONTINUE TO DEVELOP VICINITY AIRFIELD SO WILL CONTINUE WITH
TEMPO TSRA 19Z-23Z. COULD SEE SOME LIGHT FOG AT AIRFIELD CIRCA
SUNRISE.

ELSEWHERE...OVERALL CONDITIONS SIMILAR TO CLT WITH SCT TSRA
DEVELOPING. EXPECT THAT ALL AIRFIELDS WILL HAVE STORMS IN VICINITY
SO WILL CARRY TEMPO TSRA THIS AFTERNOON. SOME MVFR FOG AND PATCHY
IFR CONDITIONS LATE TONIGHT.

OUTLOOK...AN UPPER LEVEL TROUGH WILL AMPLIFY ACROSS THE ATLANTIC
STATES LATE IN THE WEEK...WITH THE PASSAGE OF A SURFACE COLD FRONT
THURSDAY NIGHT. THE POTENTIAL FOR CONVECTION WILL INCREASE THURSDAY
AFTERNOON AND EVENING WITH THE FRONTAL PASSAGE. GENERALLY DRY AND
QUIET WEATHER IS EXPECTED FRIDAY THROUGH THE WEEKEND.

CONFIDENCE TABLE...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       LOW   57%     HIGH 100%     HIGH 100%     MED   75%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     LOW   41%
KHKY       MED   64%     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...NONE.
SC...NONE.

&&

$$
SYNOPSIS...HG
NEAR TERM...LG
SHORT TERM...HG
LONG TERM...HG
AVIATION...LG



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