750
FXUS62 KGSP 161458
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1058 AM EDT TUE JUL 16 2019
SYNOPSIS
HIGH PRESSURE WILL BE IN CONTROL OF THE WEATHER ACROSS THE AREA FOR
MUCH OF THE WEEK, WHILE THE REMNANTS OF BARRY REMAIN TO THE WEST OF
THE REGION. HOT AND HUMID CONDITIONS, WITH SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS CAN BE EXPECTED EACH DAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 10:45AM EDT TUESDAY: FORECAST ON TRACK WITH A FEW
THUNDERSTORMS POSSIBLE THIS AFTERNOON, PRIMARILY OVER THE
MOUNTAINS OF WESTERN NORTH CAROLINA. CURRENT RADAR IS CLEAR, AND
UPDATED POP TREND TO INCORPORATE LATEST HIGH-RES MODEL GUIDANCE
WHICH HAS SHOWERS INCREASING THIS AFTERNOON.
SHORT WAVE RIDGING WILL REMAIN OVER THE CAROLINAS TODAY, DOWNSTREAM
OF THE WEAKENING CIRCULATION OF TC BARRY REMNANTS. THIS FEATURE WILL
CONTINUE TO CREATE AN ENVIRONMENT THAT IS NOT IDEAL FOR CONVECTIVE
INITIATION, BUT AS WAS THE CASE YESTERDAY, SUFFICIENT INSTABILITY
AND LOW LEVEL MOISTURE WILL EXIST TO ALLOW ISOLATED TO WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP THIS AFTERNOON. THE
HRRR WAS THE ONLY GUIDANCE SOURCE THAT ACCURATELY INITIATED
CONVECTION ACROSS UPSTATE SC YESTERDAY AFTERNOON (AND EVEN IT DID
NOT DEVELOP CONVECTION FAR ENOUGH TO THE NORTH), AND IT IS DOING
SOMETHING SIMILAR AGAIN THIS AFTERNOON, IN THE VICINITY OF LINGERING
WEAK TROUGH AXIS/SUBTLE BOUNDARY.
MEANWHILE, TERRAIN DIFFERENTIAL HEATING SHOULD AGAIN WORK ITS MAGIC
IN ALLOWING ISOLATED TO WIDELY SCATTERED CELLS TO DEVELOP NEAR THE
PEAKS AND RIDGE TOPS DURING EARLY/MID AFTERNOON. ONE KEY INGREDIENT
THAT IS MISSING FROM YESTERDAY IS THAT WITH THE APPROACH OF THE
TROUGH ASSOCIATED WITH BARRY'S REMNANTS, MID-LEVEL FLOW SHOULD
INCREASE ENOUGH TO RESULT IN MEAN CLOUD-BEARING WINDS OF 10-15 KTS.
THEREFORE, WHILE MODEST LEVELS OF DCAPE WILL PROBABLY RESULT IN
DEVELOPMENT OF NOT-ESPECIALLY-ACTIVE OUTFLOW BOUNDARIES, FASTER CELL
MOTION SUGGESTS CONVECTION SHOULD HAVE BETTER SUCCESS IN MAKING IT
OFF THE HIGH TERRAIN INTO THE NC FOOTHILLS AND PIEDMONT THIS
AFTERNOON. ALL THAT'S TO SAY THAT WE CAN'T SEE ANY REASON WHY
ISOLATED CONVECTION WON'T BE POSSIBLE AT ANY LOCATION ACROSS THE CWA
LATER TODAY, AND SLIGHT CHANCE POPS ARE ADVERTISED EVERYWHERE EAST
OF THE MTNS. CONVECTION SHOULD AGAIN DIMINISH QUICKLY THIS
EVENING.
WITH LINGERING OUTFLOW CIRRUS BECOMING INCREASINGLY THIN ACROSS THE
AREA TODAY, AND HEIGHTS CONTINUING TO SLOWLY RISE, THE WARMING TREND
IS EXPECTED TO CONTINUE, AND MAXES ARE EXPECTED TO TOP OUT ABOUT A
CATEGORY ABOVE CLIMO. THIS MEANS MUCH OF THE PIEDMONT IS LIKELY TO
SEE THE MID-90S. HOWEVER, DEWPOINTS ARE FORECAST TO MIX OUT JUST
ENOUGH TO SEE MAXIMUM HEAT INDEX VALUES CONFINED TO THE 95-100
RANGE, WELL BELOW ADVISORY CRITERIA OF 105.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
AS OF 230 AM TUESDAY: THE REMNANT MID-LVL TROUGH FROM BARRY WILL
CROSS THE OHIO VALLEY ON WEDNESDAY AND INTO THE SOUTHERN
APPALACHIANS WEDNESDAY NIGHT. THIS WILL LIKELY ENHANCE CONVECTIVE
COVERAGE OVER THE MOUNTAINS LATE WEDNESDAY THRU THURSDAY. CONFIDENCE
ON HOW MUCH CONVECTION EAST OF THE MOUNTAINS IS STILL LOW, AS
GUIDANCE HAS TRENDED LESS EXCITED THAN PREVIOUS RUNS. STILL, WILL GO
WITH CHC POPS WEDNESDAY NIGHT EVERYWHERE, WITH SOME LIKELIES NEAR
THE TN BORDER. CONVECTIVE COVERAGE SHOULD REMAIN A LITTLE ELEVATED
ON THURSDAY, AS PWATS NEAR 2.0" FROM BARRY WILL STILL BE OVER THE
AREA. IT WILL BE HOT AND HUMID BOTH DAYS, WITH HIGHS MAINLY IN THE
LOWER TO MID 90S IN THE PIEDMONT AND MIDDLE TO UPPER 80S IN THE
MOUNTAIN VALLEYS. AS USUAL WITH SUMMERTIME CONVECTION, THERE WILL BE
A SMALL PULSE SEVERE AND LOCALIZED FLOODING THREAT.
LONG TERM /FRIDAY THROUGH MONDAY/
AS OF 300 AM TUESDAY: A MID-LEVEL RIDGE WILL BUILD AND PERSIST
ACROSS THE EASTERN CONUS FRIDAY THRU THE WEEKEND, THEN A LONGWAVE
TROUGH WILL BEGIN TO DIG ACROSS THE EASTERN CONUS EARLY NEXT WEEK.
THIS WILL RESULT IN MAX TEMPS BACK TO THE MID TO POSSIBLY SOME UPPER
90S, WITH DEWPTS IN THE 70S. THIS WILL COMBINE TO PRODUCE HEAT INDEX
VALUES IN THE 100-105 RANGE ACROSS THE PIEDMONT EACH AFTERNOON. SOME
LOCATIONS IN THE UPPER SAVANNAH VALLEY AND EASTERN UPSTATE MAY HAVE
HEAT INDEX VALUES ABOVE 105 FRIDAY THRU SUNDAY. DESPITE THE UPPER
RIDGE CENTERED NEARLY DIRECTLY OVER THE FORECAST AREA, DAILY DIURNAL
CONVECTION IS FORECAST TO TRIGGER ACROSS THE MOUNTAINS AND ALONG A
PERSISTENT "HEAT" PIEDMONT SFC TROUGH. GUIDANCE HAS SLIGHTLY ABOVE
CLIMO POPS, MAINLY IN THE CHC TO LOW LIKELY RANGE EACH DAY.
AVIATION /15Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: LIFR CONDITIONS ARE FORECAST TO PERSIST AT
KAVL THROUGH 13Z, AND POSSIBLY AS LATE AS 14Z. THERE HAVE BEEN BRIEF
PERIODS OF VLIFR THROUGHOUT THE MORNING HOURS, AND WOULDN'T RULE OUT
ADDITIONAL PERIODS OF SUCH, BUT IT'S NOT LIKELY. OTHERWISE, VFR
CONDITIONS ARE FORECAST AT THE TERMINALS THROUGH AT LEAST THIS
EVENING. ISOLATED TO WIDELY SCATTERED CONVECTION WILL DEVELOP OVER
THE AREA THIS AFTERNOON, WITH THE BEST CHANCES AGAIN EXPECTED NEAR
KAVL, WHERE VCTS/PROB30 FOR TSRA ARE CARRIED FROM MID-AFTERNOON INTO
THE EARLY EVENING. CONVECTION IS CERTAINLY POSSIBLE AT THE OTHER
SITES, BUT COVERAGE IS EXPECTED TO BE LIMITED ENOUGH TO PRECLUDE A
MENTION ATTM. ANY CONVECTION SHOULD DIMINISH QUICKLY THIS EVENING.
FOG/LOW STRATUS WILL BE PRIMARILY A CONCERN IN THE MTN VALLEYS WEST
OF KAVL EARLY WED MORNING, BUT IS NOT AT ALL OUT OF THE QUESTION AT
KAVL, ESPECIALLY IF THE SITE RECEIVES ANOTHER ROUND OF RAIN THIS
AFTERNOON (MVFR VISBY IS CARRIED THERE FOR THE TIME BEING). WINDS
WILL INCREASE OUT OF THE SW AT 5-10 KTS BY EARLY AFTERNOON BEFORE
BECMG LIGHT/VARIABLE AGAIN TUE EVENING.
OUTLOOK: TYPICAL SCATTERED DIURNAL CONVECTION IS EXPECTED THROUGH
THE WEEK, ESPECIALLY OVER THE MOUNTAINS. PATCHY MOUNTAIN VALLEY
FOG AND LOW CIGS REMAIN POSSIBLE DURING THE OVERNIGHT AND EARLY
MORNING HOURS.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-12Z
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 83%
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:
WWW.WEATHER.GOV/GSP/AVIATION
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...ARK
NEAR TERM...JDL/WJM
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...JDL
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page