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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
135 PM EDT WED JUL 30 2014

.SYNOPSIS...
CANADIAN HIGH PRESSURE OVER THE AREA WILL LEAD TO WELL BELOW NORMAL 
TEMPERATURES MORE TYPICAL OF LATE SUMMER OR EARLY AUTUMN. AS THE 
SURFACE HIGH WEAKENS...MOISTURE WILL RETURN FOR THE WEEKEND 
INCREASING THE CHANCES OF WIDESPREAD SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS 1215 PM...CURRENT FORECAST CONTINUES TO BE RIGHT ON THE MONEY. 
ONLY VERY MINOR ADJUSTMENTS TO TEMP/DEWPOINT TREND.

AS OF 940 AM...CURRENT GRID SUITE VERIFYING VERY WELL THIS MORNING. 
THIS UPDATE WILL MAKE ONLY VERY MINOR ADJUSTMENTS BASED ON LATEST 
CONSSHORT RUN.

AS OF 600 AM EDT WEDNESDAY...CURRENT FORECAST REMAINS ON TRACK.  
ALTHOUGH ALL TIME RECORD LOW AT KAVL HAS OFFICIALLY BEEN 
TIED...LATEST SATELLITE DIFFERENCE PRODUCT AND OBS INDICATE 
DEVELOPMENT OF LOW LEVEL STRATUS IN THE REGION.  THIS WILL LIKELY 
INHIBIT ANY FURTHER COOLING THUS PROTECTING THE RECORD.  TWEAKED 
TEMPERATURES AND DEWPOINTS IN THE EXTREME NEAR TERM TO REFLECT 
LATEST OBSERVATIONAL TRENDS.

PREVIOUS DISCUSSION... 

AS OF 300 AM EDT WEDNESDAY...UPPER VORTEX CENTERED OVER EASTERN 
ONTARIO CONTINUES TO ROTATE WHILE ITS TROF REMAINS DRAPED TO THE 
SOUTH ACROSS THE EASTERN UNITED STATES.  AS THE PRIMARY TROF AXIS 
SHIFTS EASTWARD...EXPECTING A SLOW RISE IN UPPER HEIGHTS ACROSS THE 
SOUTHERN/CENTRAL APPS.  AT THE SURFACE...HIGH PRESSURE BUILDING IN 
FROM THE NORTHWEST WILL SLOWLY SLIDE EAST THROUGH THE PERIOD.  THE 
COMBINATION OF DEPARTING UPPER TROF...RISING HEIGHTS ALOFT...AND 
DOMINATE HIGH PRESSURE AT THE SURFACE WILL ONCE AGAIN YIELD A NICE 
DAY ACROSS THE REGION.  FORECAST WILL FEATURE NO MENTIONABLE POPS 
THROUGH THE PERIOD WITH THE EXCEPTION OF A FEW HOURS THIS AFTERNOON 
WHERE WEAK UPSLOPE SHOWERS ARE POSSIBLE IN THE CLIMO FAVORED REGIONS 
OF THE UPPER FRENCH BROAD.  

ASIDE FROM THAT...EXPECTING PARTLY CLOUDY SKIES AS MOISTURE IN THE 
LOW LEVELS CONDENSES LEADING TO SCATTERED FAIR WX CU.  NORTHERLY 
WINDS THROUGH THE PERIOD WILL REMAIN IN THE 5-8KTS RANGE WITH SOME 
MINOR GUSTING POSSIBLE IN/AROUND THE FRENCH BROAD VALLEY DUE TO 
CHANNELING.  TEMPERATURES THROUGH THE NEAR TERM WILL REMAIN BELOW 
NORMAL.  THAT SAID...THERE WILL BE SOME MODERATION IN THE MOUNTAINS 
LATE IN THE PERIOD AS OVERNIGHT LOWS ON THURSDAY MORNING WILL BE A 
FEW DEGREES WARMER...YET STILL BELOW NORMAL.  THESE SLIGHTLY WARMER 
TEMPERATURES COMBINED WITH LIGHT/CALM WINDS OVERNIGHT COULD LEAD TO 
REEMERGENCE OF PATCHY MOUNTAIN VALLEY FOG BY MID MORNING THURSDAY.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 315 AM...THE DEEP BROAD UPPER TROF OVER THE ERN CONUS REMAINS 
THE DOMINANT WEATHER FEATURE THROUGH THE SHORT RANGE. THE AXIS OF 
THE TROF SETS UP OVER THE MS RIVER VALLEY AND SHARPENS THRU THE 
PERIOD. IN ADDITION...THE RIDGE OVER THE ATLANTIC BUILDS WEST TOWARD 
THE EAST COAST. THIS DEVELOPS THEN STRENGTHENS THE SWLY FLOW OVER 
THE CWFA THUR THE PERIOD. A SERIES OF SHORT WAVES MOVE THRU THE FLOW 
AND ACROSS THE AREA THRU THIS TIME...WHILE THE RIGHT ENTRANCE REGION 
OF THE UPPER JET SETS UP ACROSS THE AREA INCREASING UPPER 
DIVERGENCE. LOW LEVEL S TO SE FLOW DEVELOPS ACROSS THE AREA IN 
RESPONSE TO A WEAK H85 LOW SLOWLY MOVING INTO THE AREA. ALTHOUGH THE 
LOW LEVEL MOISTURE BECOMES WIDESPREAD...THE FLOW IS NOT VERY STRONG. 
AT THE SFC...THE PATTERN TAKES ON A WEDGE LIKE CONFIGURATION AS HIGH 
PRESSURE RIDGES OVER THE AREA FROM THE NE WHILE A SFC FRONT MOVES 
NORTH TO THE ATLANTIC COAST. THE FRONT BECOMES STATIONARY THERE AS 
WEAK WAVES OF LOW PRESSURE MOVE ALONG THE FRONT. ALL THIS LEADS TO 
SLOWLY INCREASING CHC POP ACROSS THE CWFA. HOWEVER...THERE IS STILL 
SOME QUESTION ON WHERE THE BEST PRECIP COVERAGE DEVELOPS. BETTER 
COVERAGE COULD DEVELOP TO OUR SE CLOSER TO THE SFC FRONT...IT COULD 
BE ALONG THE BLUE RIDGE IN THE BETTER UPSLOPE FLOW...OR IT COULD 
EVEN BE WEST OF THE BLUE RIDGE ACROSS THE NC MTNS WHERE BETTER 
FORCING FROM THE H85 LOW MOVES. FOR NOW...CHC POP MTNS AND SLIGHT 
CHC ELSEHWERE THU AS MOISTURE AND LIFT WILL ONLY BE SLOWLY RAMPING 
UP. POP BECOMES LIKELY ACROSS THE MTNS AND NRN TIER WITH SOLID CHC 
POP ELSEHWERE THU NITE...FRI AND FRI NITE. INSTABILITY DOES SLOWLY 
INCREASE THRU THE PERIOD AS MID LEVEL CAP ERODES LEADING TO AN 
INCREASE IN ISOLATED TO SCT TSRA. QPF AMOUNTS ARE IN QUESTION AS 
WELL. FOR NOW...HAVE THE HIGHEST QPF ALONG AND WEST OF THE BLUE 
RIDGE...BUT NO HEAVY RAIN. HIGHS AROUND 5 DEGREES BELOW NORMAL THU 
FALL TO AROUND 10 DEGREES BELOW NORMAL FRI. LOWS NEAR NORMAL THU 
NITE FALL TO AROUND 5 DEGREES BELOW FRI NITE.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 AM...SWLY FLOW REMAINS ACROSS THE AREA EARLY IN THE MEDIUM 
RANGE AS THE UPPER TROF AXIS ONLY SLOWLY MOVES EAST. THIS KEEPS THE 
MOIST SLY FLOW AND WEDGE LIKE RIDGE-FRONT PATTERN IN PLACE ON SAT 
THEN SLOWLY BREAKS IT DOWN ON SUN. THIS MEANS SOLID CHC TO LIKELY 
POP AND BELOW NORMAL TEMPS CONTINUE THUR SUN NITE. 

THE GUIDANCE THEN DEVELOPS AN UPPER LOW TO OUR WEST ON MON. THE GFS 
SLOWLY MOVES THE LOW INTO THE AREA BY TUE...WHILE THE ECMWF HAS THE 
LOW DEVELOPING NEAR THE GULF COAST AND RETROGRADES IT ON TUE. EVEN 
THOUGH THE GUIDANCE DIFFERS...BOTH MDLS SHOW SCT DIURNAL CONVECTION 
MON AND TUE. THE MAIN DIFFERENCE IS THE GFS HAS MUCH MORE QPF. FOR 
NOW...HAVE DIURNAL SCT COVERAGE EACH DAY. TEMPS SHOW A SLOW WARMING 
TREND BOTH DAYS.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD DESPITE 
INCREASING MOISTURE AS BOUNDARY LAYER WINDS TURN TO THE SE. LOW VFR 
CIGS ARE A GOOD BET BY LATE TONIGHT. SFC WINDS WILL BE LIGHT.

ELSEWHERE...MUCH THE SAME AS KCLT WITH VFR CONDITIONS PREVAILING 
THROUGH THE PERIOD WITH THE EXCEPTION OF POSSIBLE MVFR FOG AT KAVL 
EARLY THURSDAY MORNING. SHOWER CHANCES WILL BE INCREASING ON THU BUT 
POPS TOO LOW BEFORE 18Z TO MENTION IN TAFS.

OUTLOOK...MOISTURE WILL CONTINUE TO INCREASE THROUGH THE REMAINDER 
OF THE WORK WEEK AS A WARM FRONT APPROACHES FROM THE EAST AND
SOUTHEASTERLY FLOW CONTINUES. UNSETTLED WEATHER WITH ENHANCED 
PRECIPITATION CHANCES ALONG WITH MORNING FOG/STRATUS THROUGH THE 
WEEKEND.

CONFIDENCE TABLE...

            17-23Z        23-05Z        05-11Z        11-17Z 
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%     
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%     
KAVL       HIGH 100%     HIGH 100%     HIGH  91%     HIGH  95%     
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...RWH
NEAR TERM...LG
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...LG

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