Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 021012
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
612 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 /THROUGH TONIGHT/...
1000 UTC UPDATE...POPS AND QPF HAVE BEEN ADJUSTED PER RADAR
TRENDS. WINDS WERE UPDATED TO INCORPORATE THE LATEST NAM GUIDANCE.
SKY COVER WAS INCREASED IN AREA AND TIME PER INFRARED SATELLITE
IMAGERY.

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 /FRIDAY THROUGH SATURDAY NIGHT/...
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 /SUNDAY 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 /10Z THURSDAY THROUGH MONDAY/...
AT KCLT...VFR. GUIDANCE STILL REFRAINS FROM GIVING THE FIELD A
DAYBREAK VSBY RESTRICTION...AND BETWEEN THE 4 DEGREE DEWPOINT
DEPRESSION AND THE WIND STAYING UP...THIS SEEMS TO BE THE RIGHT
MOVE. CIGS ARE NOW EXPECTED TO LOWER TO LOW VFR EARLIER IN THE DAY
PER OBSERVATION TRENDS. SHOWERS MOVING EAST OVER THE UPPER SAVANNAH
RIVER VALLEY APPEAR TO BE TRACKING TO ARES SOUTH OF KCLT...BUT BY
AFTERNOON MORE WIDESPREAD ACTIVITY IS EXPECTED WITH DAYTIME HEATING.
LIMITED INSTABILITY WILL NOT BE VERY SUPPORTIVE OF SEVERE
WEATHER...BUT A VERY MOIST ATMOSPHERIC COLUMN MAY SUPPORT MODERATE
RAINFALL AT TIMES. WIND WILL FAVOR THE SW...WITH DAYTIME GUSTS.
GUIDANCE BRINGS MVFR CIGS TOWARD KCLT AT DAYBREAK FRIDAY...BUT FOR
NOW CONFIDENCE IS LOW ENOUGH TO KEEP A LOW VFR CIG AT THE FIELD.
PREFERRED GUIDANCE DOES NOT FAVOR FOG FRIDAY MORNING.

ELSEWHERE...SHOWERS WILL IMPACT THE SC SITES...MAINLY KAND...THIS
MORNING...WITH LESSER CHANCES FOR ACTIVITY IN NC UNTIL MODEST
HEATING ENSUES. GUIDANCE FAVORS MVFR VSBY IN FOG AT KAVL THIS
MORNING. BY AFTERNOON MORE WIDESPREAD COVERAGE IS EXPECTED. LIMITED
INSTABILITY WILL MEAN LOW CHANCES FOR SEVERE WEATHER...BUT A MOIST
ATMOSPHERE COULD SUPPORT MODERATE RAINFALL AT TIMES. WINDS WILL
FAVOR THE SW WITH DAYTIME GUSTS...EXCEPT AT KAVL WHERE WINDS WILL
CHANNEL UP THE VALLEY FROM THE NW. GUIDANCE IS LESS CERTAIN OF VSBY
RESTRICTIONS FRIDAY MORNING.

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...

            09-15Z        15-21Z        21-03Z        03-06Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  91%     HIGH  98%     HIGH 100%     HIGH  97%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH  98%     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...JAT
NEAR TERM...JAT
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...JAT



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