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 281047
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
647 AM EDT FRI AUG 28 2015

.SYNOPSIS...
WEAK HIGH PRESSURE WILL LINGER OVER THE EAST THROUGH THE UPCOMING
WEEKEND. MOISTURE WILL GRADUALLY RETURN FROM THE SOUTHWEST THROUGH
THE WEEKEND...ALONG WITH A PASSING UPPER LEVEL DISTURBANCE BY
SUNDAY. TROPICAL SYSTEM ERIKA WILL LIKELY BE SOMEWHERE IN THE
VICINITY OF FLORIDA MONDAY THROUGH TUESDAY...WITH HIGH UNCERTAINTY
ON HER LOCATION MID TO LATE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM...LATEST OBSERVATIONS INDICATED A PATCH OF LOW CLOUDS
ACROSS THE UPSTATE OF SC AND HIGHER MTN RIDGES. FORECAST SOUNDINGS
AND 11U-3.9U SATELLITE INDICATED A SIGNIFICANT LAYER OF STRATUS
ACROSS KAND...KGMU...KGSP...AND POSSIBLY KAVL DURING THE EARLY
DAYLIGHT HOURS THROUGH MID TO LATE MORNING. I WILL UPDATE THE
FORECAST TO REFLECT THE LATEST CLOUD TRENDS.

AS OF 540 AM...IR SATELLITE AND OBSERVATIONS INDICATED MOSTLY CLOUDY
CONDITIONS ACROSS THE MTNS...FOOTHILLS...AND UPPER SAVANNAH RIVER
VALLEY. I WILL UPDATE THE FORECAST TO INCREASE SKY COVER THROUGH
EARLY THIS MORNING. OTHERWISE...THE CURRENT FORECAST REMAINS ON
TRACK.

AS OF 315 AM...SFC HIGH PRESSURE WILL REMAIN CENTERED OVER
NY/PA TODAY...RIDGING SOUTH ACROSS THE WESTERN CAROLINAS. LLVL FLOW
IS FORECAST TO REMAIN FROM THE EAST...WITH SPEEDS GRADUALLY
DECREASING TO AFTERNOON VALUES BELOW 10 KTS. THE LLVL WINDS WILL
LIKELY RESULT IN UPSLOPE FLOW...YIELDING CLOUD COVER ACROSS THE MTNS
THROUGH MOST OF THE DAY. IN ADDITION...STRATUS OVER THE MIDLANDS ARE
FORECAST TO SLIDE OVER THE UPPER SAVANNAH RIVER VALLEY AND UPSTATE
EARLY THIS MORNING. CLOUD COVER SHOULD GRADUALLY THIN WITH THE
DECREASE IN LLVL EAST WINDS THIS AFTERNOON. FORECAST NAM SOUNDINGS
AND PLAIN VIEW OF CAPE INDICATE VERY WEAK VALUES ACROSS THE FORECAST
AREA THIS AFTERNOON. THE GREATEST CAPE VALUES SHOULD OCCUR ACROSS
THE MTNS...BUT LIKELY LESS THAN A 1000 J/KG. THE INSTABILITY WILL BE
LIMITED BY A SIGNIFICANT INVERSION AROUND H7. HOWEVER...FOLLOWING
THE NAM AND 4KM WRF...I WILL HIGHLIGHT THE MTN RIDGES WITH SCHC TO
LCHC POPS DURING THE HEAT OF THE AFTERNOON. OTHERWISE...THE REGION
WILL REMAIN DRY. HIGH TEMPERATURES SHOULD PEAK A DEGREE OR TWO BELOW
NORMALS.

TONIGHT...A BROAD MID LEVEL LOW IS EXPECTED TO REMAIN NEAR THE
MISSISSIPPI DELTA...AS A SLIGHT S/W RIDGE INCREASED FROM THE EAST
ACROSS THE CAROLINAS. H925 FLOW IS FORECAST TO VEER FROM SOUTHEAST
THIS EVENING TO SOUTH BY 12Z SAT. SKY COVER MAY INCREASE FROM SOUTH
TO NORTH DURING THE LATE NIGHT HOURS. I WILL KEEP POPS IN THE SINGLE
DIGITS TONIGHT. MIN TEMPERATURES ARE FORECAST TO RANGE FROM 2 TO 4
DEGREES BELOW NORMAL.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 255 AM FRIDAY...NRN STREAM ENERGY WILL MOVE ACROSS THE GREAT
LAKES ON SATURDAY AND REACH NEW ENGLAND LATE IN THE WEEKEND.
MEANWHILE...A SRN STREAM TROUGH WILL LINGER OVER THE MID AND DEEP
SOUTH WEST OF THE APPALACHIANS. A PIECE OF THIS SRN STREAM LOW...AND
AN ASSOCIATED UPPER JETLET...WILL LIKELY LIFT NWD THROUGH THE BASE
OF THE SRN APPALACHIANS SAT NIGHT INTO SUNDAY. AHEAD OF THIS
FEATURE...MOISTURE WILL START INCREASING FROM THE SW LATE
SATURDAY...WITH THE DEEPEST MOISTURE AND FORCING THEN CROSSING THE
REGION SATURDAY NIGHT INTO SUNDAY. WILL ADVERTISE MAINLY INCREASING
CLOUDS ON SATURDAY...WITH THE BEST SHOWER CHANCES ARRIVING FROM THE
SW SAT NIGHT INTO SUNDAY MORNING. DEWPOINTS WILL STEADILY RECOVER
ALONG WITH THUNDER CHANCES THROUGH SUNDAY. WILL FEATURE A SLIGHTLY
SMALLER THAN GUIDANCE DIURNAL RANGE ON TEMPS GIVEN THE ANTICIPATED
CLOUDS OVER THE WEEKEND.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 255 AM FRIDAY...A RESURGENT RIDGE AXIS IS EXPECTED TO DEVELOP
EARLY NEXT WEEK FROM THE SRN SHORES OF THE GREAT LAKES TO THE MID
ATLANTIC COAST...AS NRN STREAM ENERGY DEPARTS NEW ENGLAND...AND THE
REMAINING SRN STREAM LOW RETROGRADES WEST INTO THE SRN PLAINS/TX.
THE RESULTING RIDGE AXIS OVER THE EASTERN UNITED STATES WILL MAKE
FOR HIGH UNCERTAINTY IN THE TRACK OF TROPICAL SYSTEM ERIKA THROUGH
THE MEDIUM RANGE PERIOD. THERE IS REASONABLY GOOD CLUSTERING OF THE
MODEL SOLUTIONS IN THE VICINITY OF FLORIDA MON INTO TUE...BUT THEN
HIGH UNCERTAINTY BEYOND THAT. WILL THUS KEEP A MAINLY DIURNAL
PATTERN OF SLIGHTLY ABOVE CLIMO POPS GOING MON THROUGH THU GIVEN THE
ANTICIPATED MID ATLANTIC BLOCKING RIDGE AND POSSIBILITY OF GRADUALLY
INCREASING TROPICAL MOISTURE WITH THE ERIKA CIRCULATION...BUT WITH
HIGH UNCERTAINTY AT THIS POINT.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR. THE LATEST RUN OF THE NAM12 INDICATES THAT LOW LEVEL
MOISTURE WILL SPREAD WEST FROM THE MIDLANDS THIS MORNING...FAVORING
THE UPSTATE OF SC AND NC FOOTHILLS. FORECAST SOUNDING OVER CLT DOES
NOT INDICATE A RESTRICTIVE CEILING THROUGH THE 12Z TAF PERIOD. WEAK
HIGH PRESSURE WILL CONTINUE TO RIDGE ACROSS THE PIEDMONT THROUGH THE
PERIOD. I EXPECT A EAST-NORTHEAST THROUGH THE DAYLIGHT
HOURS...SPEEDS 8 KTS OR LESS. THE TERMINAL IS FORECAST TO REMAIN
DRY.

ELSEWHERE...LATEST OBSERVATIONS INDICATED A PATCH OF MVFR CLOUDS
ACROSS THE UPSTATE OF SC AND HIGHER MTN RIDGES. FORECAST SOUNDINGS
AND 11U-3.9U SATELLITE INDICATED A SIGNIFICANT LAYER OF STRATUS
ACROSS KAND...KGMU...KGSP...AND POSSIBLY KAVL DURING THE EARLY
DAYLIGHT HOURS THROUGH MID TO LATE MORNING. THE CASE FOR
RESTRICTIVE...MVFR...CEILINGS REMAIN THE GREATEST FOR KAND AND KAVL.
I WILL INDICATE WINDS BACKING FROM AN EAST WIND BEFORE SUNRISE...TO
EAST-NORTHEAST THROUGH THE DAYLIGHT HOURS FRIDAY...SPEEDS 8 KTS OR
LESS. KAVL WINDS WILL REMAIN FROM THE SOUTH. THE TERMINALS ARE
FORECAST TO REMAIN DRY.

OUTLOOK...MOISTURE WILL SLOWLY INCREASE FROM THE SOUTH AND EAST
THROUGH THE WEEKEND AND THEREFORE ISOLATED TO SCATTERED AFTERNOON
AND EVENING SHRA/TSRA CHANCES WILL INCREASE.

CONFIDENCE TABLE...

            10-16Z        16-22Z        22-04Z        04-06Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       MED   78%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       MED   75%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH  94%     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

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

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


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