Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 011835
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
235 PM EDT MON JUN 1 2015

.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST ACROSS THE REGION EARLY THIS
WEEK. AN UPPER LOW IS EXPECTED TO FORM OVER THE TENNESSEE VALLEY BY
TUESDAY...REMAINING JUST WEST OF OUR REGION FOR MUCH OF THE
WEEK...WHILE COOL CANADIAN HIGH PRESSURE WILL BUILD DOWN FROM THE
NORTH. THIS PATTERN WILL HELP ENHANCE LIFT AND MOISTURE RETURN INTO
THE AREA...CREATING ELEVATED CHANCES FOR SHOWERS AND
THUNDERSTORMS...AND KEEPING TEMPERATURES SLIGHTLY BELOW NORMAL.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 150 PM...AREA TEMPS REACHING THE UPR 70S TO MID 80S ARE
RESULTING IN CONVECTIVE INITIATION...WITH RADAR RETURNS BLOSSOMING
ACRS THE CWFA. A SHARP UPPER TROF WILL BEGIN TO CLOSE OFF INTO A
COMPACT UPPER LOW OVER THE TN VALLEY...ENHANCING THE LIFT ACRS THE
AREA. POPS RAMP UP TO THE HIGH-END CHC IN THE SOUTHEAST TO
CATEGORICAL ALONG THE TN BORDER BY LATE AFTN. THE 12Z GSO/FFC
SOUNDINGS SHOWED A LOT OF MID LVL MOISTURE...WITH WEAK SHEAR AND
MODERATE LAPSE RATES. SO EXPECTING MAINLY GARDEN VARIETY
CONVECTION...WITH A COUPLE OF MARGINAL PULSE SEVERE STORMS
POSSIBLE...WITH WIND BEING THE MAIN THREAT.

CONVECTION SHUD DIMINISH TO JUST ISOLD BY THE OVERNIGHT HOURS...WITH
PLENTY OF DEBRIS CLOUDINESS PERSISTING. THE MOIST GROUND FROM THE
EXPECTED CONVECTION WILL SUPPORT PATCHY FOG AND LOW STRATUS AGAIN
TUESDAY MORNING. MIN TEMPS WILL BE A COUPLE CATEGORIES ABOVE NORMAL.

TUESDAY...THE UPPER LOW WILL SLOW DOWN OVER THE TN VALLEY...KEEPING
OUR AREA UNDER THE Q-VECTOR CONVERGENCE SIDE OF THE CIRCULATION.
MEANWHILE...A SFC FRONT WILL SAG SOUTHEAST INTO THE AREA...WITH AXIS
OF DEEP MOISTURE STILL IN PLACE. SO ANOTHER ROUND OF NUMEROUS TO
WIDESPREAD SHOWERS AND TSTMS IS EXPECTED WITH DAYTIME HEATING. THE
SEVERE THREAT LOOKS EVEN MORE MARGINAL THAN MONDAY...WITH LOW DCAPE
AND WEAK SHEAR. TEMPS WILL ALSO BE HELD IN CHECK BY PLENTY OF CLOUD
COVER AND RELATIVELY EARLY CONVECTIVE INITIATION...GENERALLY A
CATEGORY OR SO BELOW NORMAL.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 215 PM MON...CLOSED UPPER LOW REMAINS NEARLY STATIONARY OVER
THE SRN APPALACHIANS WED THEN WEAKENS ON THU AS IT MOVES SLOWLY EAST
INTO THE CWFA. AT THE SFC...A WEAK SFC BOUNDARY MOVES EAST OF THE
AREA AS HIGH PRESSURE BUILDS IN FROM THE NE IN A CAD LIKE
CONFIGURATION. THIS SHOULD LEAD TO QUITE A BIT OF CONVECTIVE
COVERAGE EACH DAY...WITH A DIURNAL TREND. HOWEVER...COPIOUS LOW
LEVEL MOISTURE AND A SELY LOW LEVEL FLOW...ALONG WITH WEAK ELEVATED
INSTABILITY...WILL HELP KEEP CONVECTION AROUND DURING THE OVERNIGHTS
AND THE MORNINGS. THERE WILL BE A CHC OF ISOLATED SVR STORMS EACH
DAY WITH DAMAGING WINDS THE MAIN THREATS. HOWEVER...THE CHANCE OF
FLOODING WILL BE ON THE INCREASE GIVEN THE HIGH PW VALUES AND
POSSIBLE TRAINING OR BACK BUILDING OF CELLS. HIGHS WILL BE A LITTLE
BELOW NORMAL EACH DAY WHILE LOWS WILL BE A LITTLE ABOVE NORMAL.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 2 PM MON...SMALL DIFFERENCES IN SYNOPTIC FEATURES OF
THE GFS AND ECMWF FOR THE MEDIUM RANGE AT LEAST ON FRIDAY AND
SATURDAY. UPPER LOW OPENS INTO THE GENERAL TROFINESS THURSDAY NIGHT
INTO FRIDAY WITH THE AFTERNOON WARMTH HELPING TO FUEL THE MORE
CONVECTIVE ACTIVITY.  THE FORECAST THROUGH THE WEEKEND AND INTO
EARLY NEXT WEEK WILL DEPEND ON THE TIMING OF SHORTWAVES AND THE
BRIEF CALM OF HIGH PRESSURE RIDGING DOWN FROM THE NORTH.  THE GFS
AND ECMWF DIFFER THE MOST IN THE DAY 6 AND 7 PORTION OF THE
FORECAST WHERE THE GFS CONTINUES ALMOST NONSTOP ACTIVITY AND THE EC
HAS SUNDAY AND MONDAY UNDER HIGH PRESSURE. BEST NOT TO MAKE MUCH
CHANGE IN THE PRIOR FORECAST TO SEE MORE CONSISTENCY TOWARD THE
LATER PERIODS. PM INSTABILITY FORECASTS HAVE TRENDED LOWER SO
PERHAPS LESS THUNDER AROUND NEXT WEEKEND. TEMPERATURES REMAIN TO BE
A LITTLE BELOW NORMAL.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AT KCLT...A CLUSTER OF SHOWERS WITHIN A SFC TROF WILL LIKELY TRACK
NEAR THE TERMINAL EARLY THIS MORNING...DEPARTING BY 14Z. I WILL
HIGHLIGHT THE CONVECTION WITH A VCSH IN THE INTIAL LINE. FORECAST
SOUNDINGS AND PERSISTENCE FOR RECENT MORNINGS SUPPORT THE FORMATION
OF MVFR STRATUS AROUND DAYBREAK...DISSIPATING BY 14Z. THE SFC TROF
WILL REMAIN THROUGH THE DAYLIGHT HOURS...RESULTING IN SOUTHWEST
WINDS THROUGH THE DAY. CAM MODELS INDICATE THAT A LINE OF TSRA WILL
DEVELOP OVER NRN GA AND THE UPSTATE OF SC THIS AFTERNOON...TRACKING
TO THE NORTHEAST...SIMILAR TO EARLY THIS MORNING. I WILL HIGHLIGHT
THE POTENTIAL FOR TSRA WITH A TEMPO FROM 19Z-23Z.

ELSEWHERE...THE PRIMARY FORECAST CHALLENGE WILL BE THE FORMATION OF
FOG AND LOW CLOUDS OVER WET GROUND...AT EACH TAF SITE THIS MORNING.
KAND HAS ALREADY OBSERVED VLIFR FOG CONDITIONS...WITH NEARBORING
SITES LIMITED TO IFR. GUIDANCE REMAINS QUITE MIXED AT THIS
TIME...HOWEVER...BASED ON THE NAM AND PERSISTENCE I WILL MENTION AT
LEAST A TEMPO FOR MVFR CEILINGS DURING THE EARLY DAYLIGHT HOURS EAST
OF THE MTNS. SOUTHWEST WINDS AROUND 5 TO 10 KTS AND CU BASED AROUND
050 SHOULD OCCUR THIS AFTERNOON. ANOTHER ROUND OF LATE AFTERNOON TO
EARLY EVENING TSRA APPEARS POSSIBLE WITH THE ARRIVAL OF A MID LEVEL
VORT...HIGHLIGHTED WITH A TEMPO. AREAS THAT RECEIVE RAINFALL WILL BE
PRIMED FOR FOG DEVELOPMENT LATE TONIGHT.

OUTLOOK...A MID LEVEL LOW IS FORECAST TO REMAIN ACROSS THE DEEP
SOUTH THROUGH THE WORK WEEK. DEEP MOISTURE WILL LINGER ACROSS
THE SOUTHEAST CONUS THROUGH THE WEEK. SHOWERS AND THUNDERSTORMS MAY
DEVELOP EACH AFTERNOON AND EVENING. MORNING STRATUS AND FOG WILL
REMAIN A POSSIBILITY...ESPECIALLY OVER WET GROUND.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  83%
KAVL       HIGH 100%     HIGH 100%     HIGH  96%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH  89%     HIGH  80%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  86%
KAND       HIGH  92%     HIGH 100%     HIGH 100%     HIGH  97%

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...DEO
NEAR TERM...ARK
SHORT TERM...RWH
LONG TERM...DEO
AVIATION...ARK



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