Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 020712
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
312 AM EDT THU JUL 2 2015

.SYNOPSIS...
A BROAD UPPER LEVEL TROUGH WILL REMAIN OVER THE SOUTHEAST THROUGH
THE WEEKEND...STEERING A SERIES OF WEAK LOW PRESSURE SYSTEMS OVER
THE REGION. THESE SYSTEMS WILL INCREASE RAIN AND THUNDERSTORM
CHANCES EACH AFTERNOON AND EVENING. HIGH TEMPERATURES WILL BE NEAR
NORMAL THROUGH NEXT WEEK...WITH LOWS JUST ABOVE NORMAL.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT 230 AM EDT THURSDAY...AN ANOMALOUS UPPER TROUGH WILL PERSIST OVER
THE EASTERN HALF OF THE NATION TODAY AND TONIGHT...WITH A RIDGE OVER
THE WEST. CHANNELED SHORTWAVE ENERGY WILL ROUND THE BASE OF THE
TROUGH...MAINLY JUST TO OUR NORTH. A SURFACE COLD FRONT IS EXPECTED
TO STALL JUST TO OUR NORTH...WITH ABUNDANT MOISTURE TO ITS SOUTH.
CLOUD COVER WILL LIMIT HEATING AND INSTABILITY...AND WITH LIMITED
SHEAR AND LITTLE DRY AIR ALOFT FOR EVAPORATIVE COOLING...CONVECTION
IS EXPECTED TO SOMEWHAT TAME. RAINFALL COULD SOMEWHAT ROBUST... BUT
STEERING FLOW SHOULD KEEP CELLS MOVING...AND LOW LEVEL FLOW PARALLEL
TO THE BLUE RIDGE WILL LIMIT UPSLOPE FLOW. HIGH TEMPERATURES WILL
RUN AROUND 6 DEGREE BELOW NORMAL UNDER CLOUDS... BUT MINIMUM
TEMPERATURES WILL ONLY RUN SLIGHTLY BELOW NORMAL DUE TO MOISTURE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
OF 240 AM THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH THE UPPER TROF FLATTENING OUT WHILE NUMEROUS LOBES OF
SHORTWAVE ENERGY STREAM ACROSS THE FCST AREA FROM THE WEST.

ON FRIDAY...DEEP LYR MOISTURE WILL BE IN PLACE OVER THE REGION FRI
MORNING AS A COMPLEX SFC LOW DEVELOPS JUST TO THE NORTH. AS THE LOW
SLOWLY MOVES TOWARDS THE COAST...ANOTHER LEE TROF WILL SET UP OVER
THE CAROLINAS LATE FRI AND LINGER WELL INTO SAT. POPS STEADILY RAMP
UP THRU THE DAY/EVENING WITH HIGH END CHANCE TO LIKELY VALUES
CARRIED OVER THE ENTIRE CWFA BY THE AFTERNOON. QPF AMOUNTS HAVE BEEN
LOWERED A BIT SINCE YESTERDAYS FCST...HOWEVER A SOLID INCH OR SO IS
POSSIBLE OVER SOME OF THE UPSLOPE AREAS AND HIGHER TERRAIN. SPC
KEEPS OUR CWFA IN THE MARGINAL RISK AREA WITH THE BIGGEST THREAT
BEING SVR STRAIGHT LINE WINDS. AS WE MOVE INTO SAT...THE SFC
LOW BEGINS TO MOVE OFF THE COAST AND ANOTHER LEE TROF DEVELOPS IN
ITS WAKE KEEPING WINDS OUT OF THE SW AND TIGHTENING THE PRESSURE
GRADIENT. PW VALUES WILL REMAIN HIGH THRU SAT...SO FLASH FLOODING
CONTINUES TO BE A CONCERN GOING FORWARD. TEMPS START OUT ABOUT 2 TO
4 DEGREES BELOW CLIMO ON FRI AND WARM A FEW DEGREES OVER THE NEXT
FEW DAYS ENDING RIGHT AROUND NORMAL FOR EARLY JULY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
OF 240 AM THURSDAY...THE MEDIUM RANGE FCST PICKS UP AT 12Z ON
SUNDAY WITH HEIGHTS RISING AS BROAD UPPER RIDGING DEVELOPS OVER MUCH
OF THE SOUTHERN CONUS. THE MODELS GENERATE NUMEROUS WEAK UPPER
SHORTWAVES THRU THE PERIOD WITH WEAK UPPER WINDS PREVAILING THRU DAY
7. NO SIGNIFICANT PATTERN CHANGES ARE EXPECTED THRU THE MEDIUM RANGE
WITH RIDGING REMAINING IN PLACE WELL BEYOND DAY 7. AT THE SFC...THE
REGION WILL REMAIN UNSETTLED THRU MOST OF THE PERIOD WITH PREVAILING
SOUTH TO SWLY LOW LVL FLOW. THE CWFA IS EXPECTED TO REMAIN UNDER
WEAK LEE TROFFING ON SUN AND MON AS A SERIES OF SHORT LIVED MESO
LOWS ATTEMPT TO SPIN UP OVER THE CAROLINAS. THE LONG RANGE GUIDANCE
SUGGESTS THAT A MORE SUBSTANTIAL FRONT WILL APPROACH THE FCST AREA
FROM THE WEST ON WED AND THURS...HOWEVER THE STRENGTH AND TIMING OF
THE SYSTEM IS UNCLEAR. THE MODELS AGREE THAT DEEPER LYR MOISTURE WILL
PERSIST OVER THE REGION THRU MOST OF THE PERIOD WITH THE HIGHEST PW
VALUES GENERALLY OVER THE NORTHERN ZONES EARLY IN THE PERIOD AND
THEN SHIFTING SOUTHWARD ON MON AND TUES. AS FOR THE SENSIBLE
FCST...I KEPT DIURNAL HIGH END CHANCES FOR CONVECTION EACH
DAY/EVENING WITH SOME LIKELY POPS OVER THE NC/TENN BORDER REGION FOR
SUN. TEMPS START OUT AROUND CLIMATOLOGY ON SUN AND WARM SLIGHTLY
OVER THE NEXT FEW DAYS WITH HIGHS TOPPING OUT JUST ABOVE CLIMO BY
EARLY NEXT WEEK.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AT KCLT...RADAR SHOWS LIGHT SHOWERS MOVING ACROSS THE AREA...BUT THE
BACK EDGE IS NOW IN THE NC FOOTHILLS. GUIDANCE IS NOT VERY EXCITED
ABOUT FOG CHANCES AT DAYBREAK...AND WITH THE WIND UP A BIT AND A 7
DEGREE DEW POINT DEPRESSION...FOG IS NOT A SURE THING. GUIDANCE
FAVORS MID LEVEL CIGS UNTIL MIDDAY...WHEN MOISTURE AND CONVECTION
ASSOCIATED WITH A FRONT TO THE NORTH LOWERS THE CIG TO LOW
VFR...WHERE IT REMAINS THROUGH THURSDAY EVENING. WINDS WILL FAVOR THE
SW...INCREASING AND BECOMING GUSTY DURING DAYLIGHT HOURS.

ELSEWHERE...LIGHT SHOWERS CONTINUE TO CROSS MOST FOOTHILLS
SITES...AND MAY PERSIST AT KGSP AND KAND FOR SOME HOURS. GUIDANCE
SUPPORTS MVFR FOG AT KAVL AT DAYBREAK...BUT NOT AT FOOTHILLS
SITES. DEW POINT DEPRESSIONS AT FOOTHILL SITES AROUND RUNNING
BETWEEN 2 AND 10 DEGREES...WITH THE LOWEST AT KAND. IF THE WIND
CAN STAY UP ENOUGH OVERNIGHT...FOG MAY BE AVOIDED...BUT THE
SITUATION WARRANT A CLOSE WATCH. MID LEVEL CIGS ARE EXPECTED TO
LOWER TO LOW VFR BY MIDDAY IN ASSOCIATIONS WITH MOISTURE AND
CONVECTION WITH A FRONT TO THE NORTH. WINDS WILL FAVOR THE SW IN
THE FOOTHILLS..AND NW AT KAVL...INCREASING DURING DAYLIGHT HOURS
WHEN GUSTS CAN BE EXPECTED.

OUTLOOK...A GRADUALLY WEAKENING UPPER TROUGH WILL SUPPORT MAINLY
AFTERNOON AND EVENING THUNDERSTORMS THROUGH EARLY NEXT WEEK.
RESTRICTIONS MAY OCCUR WITH PASSING STORMS...AND EACH MORNING OVER
RAIN SOAKED AREAS.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  98%
KAVL       HIGH  96%     HIGH  94%     HIGH 100%     HIGH  96%
KHKY       HIGH  86%     HIGH 100%     HIGH  96%     HIGH 100%
KGMU       HIGH  98%     HIGH 100%     HIGH 100%     HIGH  94%
KAND       HIGH  95%     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...JAT
NEAR TERM...JAT
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...JAT


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