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 240141
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
941 PM EDT SAT MAY 23 2015

.SYNOPSIS...
DRY CANADIAN HIGH PRESSURE WILL LINGER ATOP THE REGION THROUGH THE
HOLIDAY WEEKEND. MOIST SOUTHERLY FLOW AROUND THE BERMUDA HIGH WILL
GRADUALLY RETURN TO THE AREA BY TUESDAY WITH INCREASED CHANCES FOR
WIDESPREAD CONVECTION FOR THE LATER PORTION OF THE WORKWEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 935 PM...THE FORECAST REMAINS ON TRACK. I WILL ISSUE A UPDATE
TO ONCE AGAIN POPULATE THE HOURLY TEMPERATURES AND DEWPOINTS WITH
OBSERVATIONS. OTHERWISE...I WILL ADJUST THE WINDS A LITTLE LIGHTER
AND REDUCE POPS TO ZERO.

AS OF 745 PM...THE GOING FORECAST REMAINS IN GREAT SHAPE. I WILL
UPDATE THE FORECAST TO POPULATE HRLY TEMPS AND DEWPOINTS WITH
OBSERVATIONS. OTHERWISE...NO EDITS ARE NEED WITH THE CURRENT
FORECAST.

AS OF 120 PM EDT SATURDAY...CURRENT FCST REMAINS ON TRACK THEREFORE
NO SIGNIFICANT CHANGES WERE NEEDED/MADE WITH THIS UPDATE.  STARTING
TO SEE A FEW PATCHES OF LOW LEVEL CU OVER THE HIGH TERRAIN...WITH
MOSTLY CLEAR SKIES PREVAILING ELSEWHERE.  TEMPERATURES AROUND THE
REGION RANGE FROM MID/UPPER 60S ACROSS THE MOUNTAINS...TO MID/UPPER
70S OVER THE PIEDMONT.

PREVIOUS DISCUSSION...

AS OF 230 AM...AN UPPER RIDGE WILL CONTINUE TO BUILD ALONG A
NEGATIVELY-TILTED AXIS FROM FL TO TO MN. THE HEIGHT RISES ATOP THE
CWFA WILL HELP KEEP THINGS DRY WITH SUNNY TO MOSTLY SUNNY SKIES. THE
CENTER OF SFC HIGH PRESSURE WILL SHIFT FROM THE CENTRAL APPALACHIANS
THIS MORNING...TO JUST OFF THE MID ATLANTIC COAST TONIGHT. SO WITH
FLOW TURNING OUT OF THE SOUTHEAST...TEMPS WILL BE A CATEGORY OR TWO
WARMER TODAY THAN YESTERDAY...STILL ABOUT A CATEGORY BELOW NORMAL
FOR MOST LOCATIONS. LOWS TONIGHT UNDER MOSTLY CLEAR SKIES WILL BE
NEAR NORMAL.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 2 PM SATURDAY...EARLY NEXT WEEK LOOKS LIKE A TRANSITION INTO A
MORE SUMMER-LIKE WEATHER REGIME. THE CULPRIT WILL BE THE SLOW
EVOLUTION OF THE UPPER PATTERN THAT WILL SEE THE AXIS OF AN UPPER
RIDGE MOVE EAST OF THE FCST AREA BY MONDAY MORNING. AS THAT
HAPPENS...A GULF MOISTURE PLUME WILL MIGRATE EASTWARD RIGHT BEHIND
IT. THE RETURN FLOW OF MOISTURE FROM THE GULF/ATLANTIC WILL COMMENCE
TO THE WEST EARLY MONDAY MORNING...AND AN UPSLOPE COMPONENT AT LOW
LEVELS COULD FORCE SOME SHOWER ACTIVITY OVER THE NE GEORGIA/UPSTATE
SC BLUE RIDGE BY SUNRISE. FROM THERE...MOISTURE WILL CONTINUE TO
INCREASE OVER THE WESTERN HALF OF THE FCST AREA. THE MODEL TREND
SEEMS TO BE TO CREEP THE MOISTURE A BIT FARTHER E WITH EACH RUN...
SO THE SHOWER/TSTM CHANCE OVER THE NC MTNS/WRN UPSTATE/NE GEORGIA IS
LOOKING BETTER AND BETTER. TEMPS MIGHT BE A FEW DEGREES WARMER ON
MONDAY COMPARED TO SUNDAY. MONDAY NIGHT IS KIND OF INTERESTING IN
THAT WE MIGHT NOT SEE MUCH OF THE USUAL DIURNAL DROP IN CONVECTIVE
ACTIVITY. THE MODELS SHOW A WEAKENING BAND OF UPPER DIVERGENCE
MOVING IN FROM THE W/SW AFTER 00Z TUESDAY AS A JET STREAK LIFTS NWD
OVER THE MS VALLEY/MIDWEST...AND A WEAK VORT MAX ALSO LIFTS NE FROM
THE GULF COAST. THIS SUBTLE FORCING...ALONG WITH SOME STRENGTHENING
OF THE FLOW OUT OF THE GULF...SHOULD BE FAVORABLE FOR CONVECTION
OVERNIGHT...ESPECIALLY NEAR THE BLUE RIDGE. TUESDAY LOOKS LIKE A
DECENT CONVECTIVE PRECIP DAY AND A CHANCE WAS KEPT IN THE FCST. THE
THREAT OF SEVERE WEATHER WILL BE MITIGATED BY POOR LAPSE RATES AND
RELATIVELY WEAK INSTABILITY. TEMPS WILL CREEP ANOTHER DEGREE OR TWO
HIGHER...BUT THE INCREASE IN HUMIDITY MIGHT BE MORE NOTICEABLE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 2 PM EDT SATURDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
WEDNESDAY WITH A STEEP UPPER RIDGE AXIS CENTERED OVER THE EAST COAST
AND MULTIPLE UPPER SHORTWAVES MOVING ACROSS THE GREAT LAKES REGION.
OVER THE NEXT 24 TO 48 HOURS...THE RIDGE AXIS MOVES FARTHER EAST AND
OFFSHORE WHILE MULTIPLE UPPER SHORTWAVES PASS JUST TO OUR NORTH. THE
LONG RANGE MODELS ALSO MOVE A CLOSED UPPER LOW NW AND TOWARDS
BERMUDA ON FRI AND SAT...BUT THIS SYSTEM SHOULD NOT HAVE ANY SIG
IMPACT ON OUR FCST. ON SAT...HEIGHTS RECOVER TO SOME DEGREE AS THE
UPPER RIDGE APPEARS TO RESTRENGTHEN.

AT THE SFC...WE WILL BE UNDER THE INFLUENCE OF A TYPICAL SUMMERTIME
BERMUDA HIGH AT THE START OF THE PERIOD. THIS WILL KEEP MOIST SLY
LOW LVL FLOW OVER THE REGION THRU PRETTY MUCH THE ENTIRE PERIOD. THE
GUIDANCE INDICATES THAT SOME MINOR LOW TO MID LVL DRYING IS POSSIBLE
ON FRI AND SAT...YET IT DOES NOT APPEAR SUBSTANTIAL. THE MODELS ALSO
GENERATE AN ELONGATED COLD FRONT TO OUR NW BY THE END OF THE PERIOD.
THIS FRONT IS ASSOCIATED WITH A SFC LOW THAT DEEPENS AS IT MOVES NE
OF THE GREAT LAKES...HOWEVER IT PROBABLY WONT HAVE MUCH IMPACT ON
THE CAROLINAS UNTIL BEYOND DAY 7 IF AT ALL. AS FOR THE SENSIBLE
FCST...WE CAN EXPECT A TYPICAL WARM SUMMERTIME PATTERN WITH GOOD
CHANCES FOR WIDESPREAD SHOWERS AND TS ON WED AND THURS WITH SOMEWHAT
REDUCED CHANCES ON FRI AND SAT AS PROFILES SHOULD BE DRIER
OVERALL...BUT WITH GOOD AMOUNTS OF INSTABILITY STILL PRESENT.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...UNLIMITED VISIBILITY AND NO CEILINGS
EXPECTED THROUGH THE 0Z TAF PERIOD. THE TAFS WILL PRIMARILY FEATURE
SOUTHEAST WINDS THIS EVENING BECOMING CALM OVERNIGHT...THEN 5-10 KTS
FROM THE SOUTH-SOUTHEAST AFTER SUNRISE SUNDAY. A FEW CU MAY DEVELOP
DURING THE LATE AFTERNOON NEAR KCLT.

OUTLOOK...HIGH PRESSURE WILL SHIFT EAST OFF THE EAST COAST EARLY
NEXT WEEK...ALLOWING MOISTURE TO GRADUALLY RETURN OUT OF THE SOUTH.
CONDITIONS SHOULD REMAIN GENERALLY FAIR THROUGH THE PERIOD.

CONFIDENCE TABLE...

            01-07Z        07-13Z        13-19Z        19-00Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     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...JPT
NEAR TERM...NED
SHORT TERM...PM
LONG TERM...JPT
AVIATION...NED



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