000
FXUS62 KGSP 241813
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
213 PM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL MOVE OFF THE ATLANTIC COAST TONIGHT AND
SATURDAY WHILE SURFACE HIGH PRESSURE CONTINUES THE COOLER THAN
NORMAL TEMPERATURES THIS WEEKEND. EXPECT AFTERNOON SHOWERS AND
THUNDERSTORMS NEXT WEEK...MAINLY OVER THE MOUNTAINS. A RATHER STRONG
UPPER RIDGE WILL BRING VERY WARM TEMPERATURES FOR THE SECOND HALF
OF THE WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF MID AFTERNOON...GUSTY NW WINDS WILL CONTINUE THROUGH SUNSET
WITH A FEW CLOUDS...OTHERWISE COOL AND DRY LIKE LATE APRIL.
FOR TONIGHT...AN UPPER TROF AXIS WILL SWING OFF THE EAST COAST
LEAVING BEHIND A DEEP NW FLOW THAT WILL BRING DOWN HIGH PRESSURE AND
COOL TEMPS...MORE THAN TEN DEGREES BELOW NORMAL. THE WIND SHOULD
DIMINISH SIGNIFICANTLY BY EARLY SATURDAY MORNING. THIS COULD BE
ENOUGH TO ALLOW FOR PATCHY FROST TO DEVELOP IN SOME OF THE SHELTERED
MOUNTAIN VALLEYS...PARTICULARLY THE LITTLE TN RIVER VALLEY. THE AREA
IMPACTED DOES NOT LOOK LARGE ENOUGH FOR A FROST ADVISORY SO THE
MENTION WILL REMAIN RELEGATED TO THE HWO.
SATURDAY IS SHAPING UP TO BE A BRIGHT...SUNNY...COOL...AND DRY DAY
WITH A LIGHT BREEZE...COURTESY OF SURFACE HIGH PRESSURE RIDGING DOWN
FROM THE GREAT LAKES. CHAMBER OF COMMERCE WEATHER FOR THE FIRST PART
OF MEMORIAL DAY WEEKEND. OPEN UP THE WINDOWS AND ENJOY IT NOW
BECAUSE IT WILL NOT LAST. TEMPS WERE KEPT CLOSE TO A GUIDANCE
BLEND...WHICH IS A COMFORTABLE FIVE DEGREES OR SO BELOW NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRIDAY...NW FLOW ALOFT WILL CONTINUE THROUGH SUNDAY AS
AN INTENSE UPPER LOW MOVES THROUGH NEW ENGLAND. THE FLOW WILL
DE-AMPLIFY ON MONDAY WITH BUILDING HEIGHTS AS THE LOW MOVES OUT THE
PICTURE. AT THE SURFACE...HIGH PRESSURE WILL RIDGE SOUTH FROM THE
SOUTHERN GREAT LAKES WITH A WEAK BACKDOOR FRONT MOVING THROUGH THE
AREA ON SUNDAY. THIS FRONT WILL MOVE NORTH AS A WARM FRONT ON
MONDAY. A MORE DOMINATE HIGH IS FORECAST TO DEVELOP OFF THE SE COAST
ON MONDAY.
A SERIES OF IMPULSES EMBEDDED IN THE NW FLOW ARE FORECAST TO MOVE
ACROSS THE AREA SUNDAY AND MONDAY. THE AIRMASS OVER THE REGION WILL
BE QUITE DRY IN THE LOWER LEVELS INITIALLY WITH DEWPOINTS IN THE 30S
AND 40S ON SUNDAY. HENCE...THE LACK OF SIGNIFICANT QPF RESPONSE IN
THE MODEL FORECASTS FOR SUN/SUN NIGHT IS NOT SURPRISING. WOULD EXPECT
THAT ANY PRECIP THAT FALLS SUNDAY AND SUNDAY NIGHT WILL BE MAINLY
VIRGA OR PERHAPS SOME SPRINKLES IN THE MOUNTAINS. MONDAY IS A
SLIGHTLY DIFFERENT STORY AS LOW LEVEL MOISTURE IMPROVES WITH
DEWPOINTS RISING INTO THE 50S AS THE WARM FRONT LIFTS NE.
THEREFORE...WOULD EXPECT SOME SCATTERED SHOWERS DEVELOPING IN THE
MOUNTAINS IN THE MORNING...WITH SCATTERED SHOWERS AND PERHAPS EVEN
SOME THUNDERSTORMS IN THE AFTERNOON....MAINLY OVER THE MOUNTAINS AND
THE NC FOOTHILLS/PIEDMONT.
TEMPERATURES WILL BE BELOW AVERAGE SAT NIGHT AND SUNDAY...WITH
MODERATING TEMPS ON MONDAY APPROACHING SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 150 PM FRIDAY...STARTING AT 00Z TUESDAY ALL MODELS SHOW SOME
MID LEVEL MOISTURE BETWEEN THE DEPARTING UPPER TROUGH WITH AXIS JUST
OFF THE NEW ENGLAND COAST AND THE EXPANDING UPPER RIDGE WITH AXIS
OVER EAST TEXAS. THIS LINEAR AREA OF MOISTURE EXTENDS FROM KY TO NC
MONDAY NIGHT THEN SHIFTS EAST AS RIDGE BUILDS FROM SW. SOUTHWESTERLY
LOW LEVEL FLOW WILL BRING WARMER AIR INTO THE REGION AS TEMPERATURES
WILL BE A LITTLE ABOVE NORMAL TUESDAY AND WEDNESDAY AND THEN TWO
CATEGORIES ABOVE NORMAL FOR HIGHS THURSDAY AND FRIDAY. INSTABILITY
WILL SUPPORT PM SHOWERS AND STORMS BUT FAVORING DIFFERENTIAL HEATING
OF THE MOUNTAINS. CAPE VALUES ARE MOST UNSTABLE ON ECMWF WITH 1000
TO 2000 VALUES EACH AFTERNOON. GFS IS MORE REASONABLE WITH 800 TO
1200 TUES...DROPPING TO LESS THAN 1000 FOR THE REST OF THE WEEK WITH
HIGHEST VALUES NORTH OF CLT TOWARD VA. MODELS HAVE CENTER OF 500MB
RIDGE OVER WESTERN NC THURSDAY. SEEMS MORE STABLE ON THURSDAY AND
EVEN MORE STABLE FRIDAY WITH DRIER LOW TO MID LEVEL. UPPER RIDGE
BEGINS TO MOVE OFF THE EAST COAST GOING INTO NEXT WEEKEND.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD. A FEW STRATOCU WITH
BASES AT 050 TO 060 THROUGH SUNSET...THEN CLEAR AFTER 01Z. WIND WILL
REMAIN GUSTY FROM THE NW THROUGH SUNSET BUT WILL QUICKLY DIMINISH
AFTER THAT AS THE CENTER OF THE HIGH BUILDS IN. MOST PLACES WILL GO
LIGHT AND VARIABLE EARLY SATURDAY MORNING AND STAY THAT WAY THROUGH
THE REST OF THE TAF PERIOD...THE EXCEPTION BEING KAVL WHERE A NW
UPVALLEY WIND WILL BE MAINTAINED. COULD BE SOME FOG OR FROST IN THE
LITTLE TN RIVER VALLEY AROUND DAYBREAK SATURDAY...BUT NOT AROUND
KAVL.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED. A
RETURN TO DIURNAL THUNDERSTORMS IS EXPECTED FOR MONDAY THROUGH
WEDNESDAY WITH ASSOCIATED RESTRICTIONS IN THE VICINITY OF STORMS.
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 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
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA THIS AFTERNOON. AFTERNOON MINIMUM RELATIVE
HUMIDITY VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...PM
SHORT TERM...LG
LONG TERM...DEO
AVIATION...PM
FIRE WEATHER...
000
FXUS62 KGSP 241733
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
133 PM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL MOVE OFF THE ATLANTIC COAST TONIGHT AND
SATURDAY WHILE SURFACE HIGH PRESSURE CONTINUES THE COOLER THAN
NORMAL TEMPERATURES THIS WEEKEND. EXPECT AFTERNOON SHOWERS AND
THUNDERSTORMS NEXT WEEK...MAINLY OVER THE MOUNTAINS. A RATHER STRONG
UPPER RIDGE WILL BRING VERY WARM TEMPERATURES FOR THE SECOND HALF
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF EARLY AFTERNOON...THE FCST IS ON TRACK WITH TEMPS AND WITH
GUSTY NW WIND REMAINING BELOW ADVISORY LEVELS. NO CHANGES.
REMAINDER OF PREVIOUS DISCUSSION...
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 200 PM FRIDAY...NW FLOW ALOFT WILL CONTINUE THROUGH SUNDAY AS
AN INTENSE UPPER LOW MOVES UP THE EAST COAST. THE FLOW WILL
DE-AMPLIFY ON MONDAY WITH BUILDING HEIGHTS AS THE LOW MOVES OUT THE
PICTURE. AT THE SURFACE...HIGH PRESSURE WILL WILL RIDGE SOUTH FROM
THE SOUTHERN GREAT LAKES WITH A WEAK BACKDOOR FRONT MOVING THROUGH
THE AREA ON SUNDAY. THIS FRONT WILL MOVE NORTH AS A WARM FRONT ON
MONDAY. A MORE DOMINATE HIGH IS FORECAST TO DEVELOP OFF THE SE COAST
ON MONDAY.
A SERIES OF IMPULSES EMBEDDED IN THE NW FLOW ARE FORECAST TO MOVE
ACROSS THE AREA SUNDAY AND MONDAY. THE AIRMASS OVER THE REGION WILL
BE QUITE DRY IN THE LOWER LEVELS INITIALLY WITH DEWPOINTS IN THE 30S
AND 40S ON SUNDAY. HENCE...THE LACK OF SIGNIFICANT QPF RESPONSE IN
THE MODEL FORECASTS FOR SUNDAY IS NOT SURPRISING. WOULD EXPECT THAT
ANY PRECIP THAT FALLS SUNDAY AND SUNDAY NIGHT WILL BE MAINLY VIRGA
OR PERHAPS SOME SPRINKLES IN THE MOUNTAINS. MONDAY IS A DIFFERENT
STORY AS LOW LEVEL MOISTURE IMPROVES WITH DEWPOINGS RISING INTOT EH
50S AS THE WARM FRONT LIFTS NE. THEREFORE...WOULD EXPECT SOME
SCATTERED SHOWERS DEVELOPING INT HE MOUNTAINS IN THE MORNING...WITH
SCATTERED SHOWERS AND PERHAPS EVEN SOME THUNDERSTORMS IN THE
AFTERNOON....MAINLY OVER THE MOUNTAINS AND THE NC
FOOTHILLS/PIEDMONT.
TEMPERATURES WILL BE WELL BELOW AVERAGE THROUGH SAT NIGHT AND
SUNDAY...WITH MODERATING TEMPS ON MONDAY APPROACHING SEASONAL
LEVELS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD. A FEW STRATOCU WITH
BASES AT 050 TO 060 THROUGH SUNSET...THEN CLEAR AFTER 01Z. WIND WILL
REMAIN GUSTY FROM THE NW THROUGH SUNSET BUT WILL QUICKLY DIMINISH
AFTER THAT AS THE CENTER OF THE HIGH BUILDS IN. MOST PLACES WILL GO
LIGHT AND VARIABLE EARLY SATURDAY MORNING AND STAY THAT WAY THROUGH
THE REST OF THE TAF PERIOD...THE EXCEPTION BEING KAVL WHERE A NW
UPVALLEY WIND WILL BE MAINTAINED. COULD BE SOME FOG OR FROST IN THE
LITTLE TN RIVER VALLEY AROUND DAYBREAK SATURDAY...BUT NOT AROUND
KAVL.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED. A
RETURN TO DIURNAL THUNDERSTORMS IS EXPECTED FOR MONDAY THROUGH
WEDNESDAY WITH ASSOCIATED RESTRICTIONS IN THE VICINITY OF STORMS.
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 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
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK/PM
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...PM
FIRE WEATHER...
000
FXUS62 KGSP 241430
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1030 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TODAY...BRINGING
COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL
MODERATE BY THE BEGINNING OF NEXT WEEK...WITH A CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF MID MORNING...KMRX RADAR SHOWS LIGHT PRECIP ECHOES ON THE WANE
ALONG THE TN BORDER...SO IT WOULD APPEAR THAT ANY NW FLOW SHOWER
ACTIVITY IS ON SCHEDULE TO END DURING THE NEXT HOUR. SOME CLOUDINESS
WILL CONTINUE OVER THE HIGHER TERRAIN INTO THE EARLY AFTERNOON. THE
ONLY OTHER FEATURE OF INTEREST IS A PATCH OF CLOUDS MOVING ACROSS
METRO CLT...BUT THAT SHOULD ALSO MOVE OFF TO THE SOUTHEAST. TEMPS
LOOK OKAY FOR NOW...NO CHANGES TO THE HIGHS.
REMAINDER OF PREVIOUS DISCUSSION...
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...GENERALLY FAIR WEATHER SATURDAY THROUGH SUNDAY
NIGHT. CLOUD COVER WILL INCREASE SATURDAY NIGHT...WITH VARIABLY
CLOUDY CONDITIONS EXPECTED INTO SUNDAY NIGHT. THIS WILL BE THE
RESULT OF WARM ADVECTION ON THE BACK SIDE OF A STRONG LONG WAVE
TROUGH. OVERALL THE FORCING LOOKS WEAK AND MOST OF WHAT WE SHOULD
SEE DURING THIS PERIOD WILL BE AC/SC AND PERHAPS A FEW AREAS OF
HIGH-BASED SPRINKLES OR LIGHT SHOWERS...PARTICULARLY SATURDAY NIGHT.
MAX TEMPS SATURDAY WILL BE A COUPLE CATEGORIES BELOW
NORMAL...REBOUNDING A FEW DEGREES ON SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS THRU ABOUT 14Z. A NW
WIND EXPECTED THRU THE PERIOD...INCREASING INTO THE 10-15 KT RANGE
BY MID MORNING...WITH GUSTS IN THE 20-25 KT RANGE EXPECTED THRU THE
AFTN. WINDS DIMINISH AROUND SUNSET THIS EVENING.
AT KAVL...STRONG CHANNELED VALLEY WINDS WILL CONTINUE THRU THE DAY.
GENERALLY SUSTAINED 15-20 KTS AND GUSTS POSSIBLY IN THE 30-35 KT
RANGE. SOME MOISTURE WILL CONTINUE TO WORK UP THE VALLEY THRU ABOUT
MID MORNING...WITH ANY CIGS EXPECTED TO BE VFR. HOWEVER...BRIEF
PERIODS OF MVFR CIGS ARE POSSIBLE. SO WILL HAVE TEMPO FOR A COUPLE
HOURS. WINDS WILL BEGIN TO DIMINISH AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES THRU
THE PERIOD. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL
SITES TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS
FROM LATE MORNING THRU THE AFTN.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 99% 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
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK/PM
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...ARK
FIRE WEATHER...
000
FXUS62 KGSP 241125
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
725 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TODAY...BRINGING
COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL
MODERATE BY THE BEGINNING OF NEXT WEEK...WITH A CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM...STILL A FEW NW FLOW SHWRS ALONG THE TN BORDER...BUT
ON A DECREASING TREND. COLD AIR ADVECTION AND THE PASSAGE OF A
STRONG MID LVL SHORTWAVE IS FINALLY USHERING IN SOME BREEZY
CONDITIONS ALREADY IN THE MTNS...WITH THE FRENCH BROAD VALLEY IN A
FAVORABLE CHANNELED WIND DIRECTION THIS MORNING. STILL PLAN TO HOLD
OFF ANY WIND ADV ATTM...BUT TRENDS WILL BE WATCHED OVER NEXT COUPLE
HOURS.
AS OF 300 AM...CONDITIONS ARE GRADUALLY DRYING OUT BEHIND THE
PASSAGE OF A COLD FRONT EARLY THIS MORNING. THERE IS ENUF LLVL
MOISTURE IN THE NWLY FLOW FOR SCATTERED SHWRS TO DEVELOP AND AFFECT
THE UPSLOPE AREAS ALONG THE TN LINE. THIS ACTIVITY SHUD WANE BY MID
MORNING...AS UPPER SHORTWAVE TROF PASSES BY AND DRIER AIR WORKS IN.
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...GENERALLY FAIR WEATHER SATURDAY THROUGH SUNDAY
NIGHT. CLOUD COVER WILL INCREASE SATURDAY NIGHT...WITH VARIABLY
CLOUDY CONDITIONS EXPECTED INTO SUNDAY NIGHT. THIS WILL BE THE
RESULT OF WARM ADVECTION ON THE BACK SIDE OF A STRONG LONG WAVE
TROUGH. OVERALL THE FORCING LOOKS WEAK AND MOST OF WHAT WE SHOULD
SEE DURING THIS PERIOD WILL BE AC/SC AND PERHAPS A FEW AREAS OF
HIGH-BASED SPRINKLES OR LIGHT SHOWERS...PARTICULARLY SATURDAY NIGHT.
MAX TEMPS SATURDAY WILL BE A COUPLE CATEGORIES BELOW
NORMAL...REBOUNDING A FEW DEGREES ON SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS THRU ABOUT 14Z. A NW
WIND EXPECTED THRU THE PERIOD...INCREASING INTO THE 10-15 KT RANGE
BY MID MORNING...WITH GUSTS IN THE 20-25 KT RANGE EXPECTED THRU THE
AFTN. WINDS DIMINISH AROUND SUNSET THIS EVENING.
AT KAVL...STRONG CHANNELED VALLEY WINDS WILL CONTINUE THRU THE DAY.
GENERALLY SUSTAINED 15-20 KTS AND GUSTS POSSIBLY IN THE 30-35 KT
RANGE. SOME MOISTURE WILL CONTINUE TO WORK UP THE VALLEY THRU ABOUT
MID MORNING...WITH ANY CIGS EXPECTED TO BE VFR. HOWEVER...BRIEF
PERIODS OF MVFR CIGS ARE POSSIBLE. SO WILL HAVE TEMPO FOR A COUPLE
HOURS. WINDS WILL BEGIN TO DIMINISH AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES THRU
THE PERIOD. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL
SITES TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS
FROM LATE MORNING THRU THE AFTN.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 92% 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
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...ARK
FIRE WEATHER...
000
FXUS62 KGSP 240751
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
351 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TODAY...BRINGING
COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL
MODERATE BY THE BEGINNING OF NEXT WEEK...WITH A CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM...CONDITIONS ARE GRADUALLY DRYING OUT BEHIND THE
PASSAGE OF A COLD FRONT EARLY THIS MORNING. THERE IS ENUF LLVL
MOISTURE IN THE NWLY FLOW FOR SCATTERED SHWRS TO DEVELOP AND AFFECT
THE UPSLOPE AREAS ALONG THE TN LINE. THIS ACTIVITY SHUD WANE BY MID
MORNING...AS UPPER SHORTWAVE TROF PASSES BY AND DRIER AIR WORKS IN.
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...GENERALLY FAIR WEATHER SATURDAY THROUGH SUNDAY
NIGHT. CLOUD COVER WILL INCREASE SATURDAY NIGHT...WITH VARIABLY
CLOUDY CONDITIONS EXPECTED INTO SUNDAY NIGHT. THIS WILL BE THE
RESULT OF WARM ADVECTION ON THE BACK SIDE OF A STRONG LONG WAVE
TROUGH. OVERALL THE FORCING LOOKS WEAK AND MOST OF WHAT WE SHOULD
SEE DURING THIS PERIOD WILL BE AC/SC AND PERHAPS A FEW AREAS OF
HIGH-BASED SPRINKLES OR LIGHT SHOWERS...PARTICULARLY SATURDAY NIGHT.
MAX TEMPS SATURDAY WILL BE A COUPLE CATEGORIES BELOW
NORMAL...REBOUNDING A FEW DEGREES ON SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS FOR THE FIRST FEW HOURS
OF THE 06Z TAF. A NNW WIND EXPECTED THRU THE PERIOD...INCREASING
INTO THE 10-15 KT RANGE BY MID MORNING...WITH GUSTS IN THE 20-25 KT
RANGE EXPECTED THRU THE AFTN. WINDS DIMINISH AROUND SUNSET THIS
EVENING.
AT KAVL...STRONG GAP WINDS EXPECTED TO PICK UP BEFORE DAYBREAK...AND
CONTINUE THRU THE DAY. GENERALLY SUSTAINED 15-20 KTS AND GUSTS
POSSIBLY IN THE 30-35 KT RANGE. SOME MOISTURE WILL CONTINUE TO WORK
UP THE VALLEY THRU ABOUT MID MORNING...WITH ANY CIGS EXPECTED TO BE
VFR. HOWEVER...A BRIEF PERIOD OF MVFR CIG CANNOT BE RULED OUT...MOST
LIKELY RIGHT BEFORE OR DURING DAYBREAK. WINDS WILL BEGIN TO DIMINISH
AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES
THROUGH THE PERIOD...WITH MID CLOUDS EVENTUALLY CLEARING OUT BY
DAYBREAK. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL SITES
TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS FROM
LATE MORNING THRU THE AFTN.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 82% 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
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...ARK
FIRE WEATHER...MCAVOY
000
FXUS62 KGSP 240550
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
150 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1020 PM...CURRENT RADAR ANALYSIS PLACES A LINE OF CONVECTION
EXTENDING IN A NORTH/SOUTH ORIENTATION ACROSS THE SRN NORTH CAROLINA
PIEDMONT...TO INCLUDE CHARLOTTE METRO. THIS CONVECTION WILL
CONTINUE TO MOVE EASTWARD ACROSS CENTRAL NORTH CAROLINA BEFORE
EVENTUALLY DISSIPATING DUE TO LACK OF SURFACE ENERGY.
THUS...SLIGHTLY PULLED BACK POPS FURTHER ACROSS THE PIEDMONT TO END
SLIGHT CHANCE POPS A LITTLE SOONER THAN PREVIOUS FCST. WINDS STILL
LOOK TO BE SOMEWHAT GUSTY DURING THE DAY TOMORROW ACROSS THE ENTIRE
REGION AS SFC PRESSURE GRADIENT TIGHTENS. THUS FOR FRIDAY EXPECTING
SUSTAINED NNW WINDS NEARING 15-20KTS ACROSS THE HIGHER TERRAIN...AND
12-15KTS ELSEWHERE. LOOK FOR GUSTS IN THE MOUNTAINS TO REACH
25-30KTS AND AROUND 15-20KTS IN THE LOWER ELEVATIONS. THEREFORE NOT
FCST TO REACH WIND ADVISORY CRITERIA AT THIS TIME. FCST LOOKS TO BE
ON TRACK AND NO CHANGES WERE MADE.
REMAINDER OF PREVIOUS DISCUSSION...
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS FOR THE FIRST FEW HOURS
OF THE 06Z TAF. A NNW WIND EXPECTED THRU THE PERIOD...INCREASING
INTO THE 10-15 KT RANGE BY MID MORNING...WITH GUSTS IN THE 20-25 KT
RANGE EXPECTED THRU THE AFTN. WINDS DIMINISH AROUND SUNSET THIS
EVENING.
AT KAVL...STRONG GAP WINDS EXPECTED TO PICK UP BEFORE DAYBREAK...AND
CONTINUE THRU THE DAY. GENERALLY SUSTAINED 15-20 KTS AND GUSTS
POSSIBLY IN THE 30-35 KT RANGE. SOME MOISTURE WILL CONTINUE TO WORK
UP THE VALLEY THRU ABOUT MID MORNING...WITH ANY CIGS EXPECTED TO BE
VFR. HOWEVER...A BRIEF PERIOD OF MVFR CIG CANNOT BE RULED OUT...MOST
LIKELY RIGHT BEFORE OR DURING DAYBREAK. WINDS WILL BEGIN TO DIMINISH
AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES
THROUGH THE PERIOD...WITH MID CLOUDS EVENTUALLY CLEARING OUT BY
DAYBREAK. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL SITES
TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS FROM
LATE MORNING THRU THE AFTN.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 84% HIGH 97% 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...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...ARK
000
FXUS62 KGSP 240225
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1025 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 1020 PM...CURRENT RADAR ANALYSIS PLACES A LINE OF CONVECTION
EXTENDING IN A NORTH/SOUTH ORIENTATION ACROSS THE SRN NORTH CAROLINA
PIEDMONT...TO INCLUDE CHARLOTTE METRO. THIS CONVECTION WILL
CONTINUE TO MOVE EASTWARD ACROSS CENTRAL NORTH CAROLINA BEFORE
EVENTUALLY DISSIPATING DUE TO LACK OF SURFACE ENERGY.
THUS...SLIGHTLY PULLED BACK POPS FURTHER ACROSS THE PIEDMONT TO END
SLIGHT CHANCE POPS A LITTLE SOONER THAN PREVIOUS FCST. WINDS STILL
LOOK TO BE SOMEWHAT GUSTY DURING THE DAY TOMORROW ACROSS THE ENTIRE
REGION AS SFC PRESSURE GRADIENT TIGHTENS. THUS FOR FRIDAY EXPECTING
SUSTAINED NNW WINDS NEARING 15-20KTS ACROSS THE HIGHER TERRAIN...AND
12-15KTS ELSEWHERE. LOOK FOR GUSTS IN THE MOUNTAINS TO REACH
25-30KTS AND AROUND 15-20KTS IN THE LOWER ELEVATIONS. THEREFORE NOT
FCST TO REACH WIND ADVISORY CRITERIA AT THIS TIME. FCST LOOKS TO BE
ON TRACK AND NO CHANGES WERE MADE.
REMAINDER OF PREVIOUS DISCUSSION...
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AT KCLT...EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE ENTIRE TAF
PERIOD. LOOKS AS IF THERE MIGHT BE ENOUGH CONVECTIVE DEBRIS IN THE
REGION TO KEEP CIGS AT AROUND THE 12-15KFT LEVEL THROUGH MOST OF THE
EVENING BEFORE SCATTERING OUT BY DAYBREAK. WINDS WILL SHIFT TO A
MORE NNW COMPONENT AROUND THE 04Z TIMEFRAME AND SHOULD STAY AROUND
6-7KTS GENERALLY. OTHERWISE...WINDS WILL INCREASE AROUND 14Z FRIDAY
MORNING AS SFC PRESSURE GRADIENT TIGHTENS AND LOW LEVEL WINDS MIX
DOWN. THUS...WENT WITH PREVAILING 12KTS WITH 25KT GUSTS FOR THE
REMAINDER OF THE TAF PERIOD.
ELSEWHERE...VFR CONDITIONS CAN BE EXPECTED AT ALL TAF SITES THROUGH
THE PERIOD AND CIGS WILL IMPROVE THROUGHOUT THE EVENING. AS
WITH KCLT ABOVE...WINDS WILL BE THE GREATEST CONCERN ON FRIDAY AS
850MB FLOW ALOFT MIXES DOWN. THUS...ALL SITES HAVE GROUPS WITH
PREVAILING WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS.
KAVL LOOKS TO HAVE THE HIGHEST WIND POTENTIAL AS FLOW CHANNELS
THROUGH THE FRENCH BROAD VALLEY AND IS EXPECT TO GUST NEAR 30KTS.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 91% HIGH 85% HIGH 98% HIGH 100%
KHKY HIGH 100% HIGH 95% 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...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...CDG
000
FXUS62 KGSP 232352
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
752 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 800 PM...OVERALL COVERAGE OF SHOWERS AND THUNDERSTORMS HAS
DECREASED ACROSS THE UPSTATE AND THE NC PIEDMONT. SOME NEW SHOWER
ACTIVITY HAS TRIED TO GET GOING ACROSS THE HIGHER TERRAINS BUT LOOKS
TO BE STRUGGLING AS DAYTIME HEATING INDUCED INSTABILITY FALLS.
LATEST SURFACE OBSERVATIONS DO SHOW A FAIRLY EVIDENT WIND SHIFT TO
THE NNW ACROSS THE HIGHER TERRAINS AS THE BELOW MENTIONED FRONTAL
BOUNDARY MAKES ITS WAY INTO THE CWA. OTHERWISE...TOUCHED UP
TEMPERATURES AND MADE NO OTHER CHANGES TO THE FCST.
REMAINDER OF PREVIOUS DISCUSSION...
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AT KCLT...EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE ENTIRE TAF
PERIOD. LOOKS AS IF THERE MIGHT BE ENOUGH CONVECTIVE DEBRIS IN THE
REGION TO KEEP CIGS AT AROUND THE 12-15KFT LEVEL THROUGH MOST OF THE
EVENING BEFORE SCATTERING OUT BY DAYBREAK. WINDS WILL SHIFT TO A
MORE NNW COMPONENT AROUND THE 04Z TIMEFRAME AND SHOULD STAY AROUND
6-7KTS GENERALLY. OTHERWISE...WINDS WILL INCREASE AROUND 14Z FRIDAY
MORNING AS SFC PRESSURE GRADIENT TIGHTENS AND LOW LEVEL WINDS MIX
DOWN. THUS...WENT WITH PREVAILING 12KTS WITH 25KT GUSTS FOR THE
REMAINDER OF THE TAF PERIOD.
ELSEWHERE...VFR CONDITIONS CAN BE EXPECTED AT ALL TAF SITES THROUGH
THE PERIOD AND CIGS WILL IMPROVE THROUGHOUT THE EVENING. AS
WITH KCLT ABOVE...WINDS WILL BE THE GREATEST CONCERN ON FRIDAY AS
850MB FLOW ALOFT MIXES DOWN. THUS...ALL SITES HAVE GROUPS WITH
PREVAILING WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS.
KAVL LOOKS TO HAVE THE HIGHEST WIND POTENTIAL AS FLOW CHANNELS
THROUGH THE FRENCH BROAD VALLEY AND IS EXPECTED TO GUST NEAR 30KTS.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 98% MED 79% HIGH 91% HIGH 100%
KHKY HIGH 100% HIGH 94% 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...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...CDG
000
FXUS62 KGSP 232100
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
500 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 445 PM...SCATTERED CONVECTIVE ACTIVITY CONTINUES ACROSS
NORTHERN MOST PORTIONS OF THE UPSTATE...AND INTO THE THE NC
PIEDMONT. VISIBLE SATELLITE TRENDS ARE ACTUALLY SHOWING A DECREASE
IN THE CU FIELD ACROSS THE UPSTATE....THEREFORE ADJUSTED TEMPERATURE
TRENDS TO ACCOUNT FOR THIS AND ANY OUTFLOW COOLING FROM ADJACENT
CONVECTION. EXTENDED ZONE OF LIKELY POPS IN THE NEAR TERM FURTHER
WEST ACROSS THE PIEDMONT AS NEAR TERM GUIDANCE KEEPS CURRENT
ACTIVITY GOING IN THIS REGION FOR THE NEXT 3-4 HOURS. OTHERWISE...NO
OTHER CHANGES WERE MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...CANNOT RULE OUT ONE OR TWO SEVERE CELLS GIVEN
SUFFICIENT CAPE ON THE LATEST LAPS ANALYSIS AND SOME DCAPE AS
WELL...BUT NEITHER IS AS GOOD AS YESTERDAY. NE GEORGIA AND THE
UPSTATE WILL HAVE THE LEAST CHANCE OF PRECIP BECAUSE OF A LACK OF
TRIGGER.
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
AT KCLT FOR 21Z UPDATE...HAVE HELD ONTO A TWO HOUR WINDOW OF
THUNDERSTORMS FROM EARLIER TAF ISSUANCE IN THE 21Z TO 23Z TIME RANGE
PER THE 4KM WRF MODEL AND RECENT RADAR TRENDS. THUS...KEPT PREVIOUS
TEMPO GROUP AS IS WITH THE ONLY CHANGE BEING TO WINDS WITH MENTION
OF VRB10 GUSTING TO 20KTS ADJACENT TO ANY THUNDERSTORMS. THE FRONT
SHOULD FINALLY CROSS THE REGION DURING THE MIDDLE PART OF THE
EVENING WHICH WILL CLEAR OUT THE LOW CLOUDS AND SHIFT THE WIND FROM
SW TO NW...BY 04Z AT THE LATEST. CONDITIONS SHOULD BE VFR FROM THAT
POINT ONWARD. ON FRIDAY...ONCE THE WINDS COME UP DURING MID
MORNING...EXPECT FREQUENT GUSTS FROM THE NW.
ELSEWHERE...SIMILAR CHANCES FOR MVFR CEILING UNTIL 20Z OR SO WHEN
THE BOUNDARY LAYER LIFTS THE CLOUD BASES ABOVE 030. OTHERWISE...
LESS OF A CHANCE FOR CONVECTIVE ACTIVITY. ONLY KHKY WARRANTS A
VICINITY THUNDERSTORM FOR THE TIME BEING. EXPECT VFR CONDITIONS
AFTER FRONTAL PASSAGE...WHICH SHOULD BE LATE AFTERNOON TO EARLY
EVENING. SOME UPSLOPE SHOWERS COULD OCCUR ALONG THE TN BORDER...BUT
THIS IS NOT EXPECTED TO AFFECT KAVL. WINDS SHOULD BE STRONG AND
GUSTY FROM THE NW ON FRIDAY.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 92% MED 76% HIGH 85% 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 93% 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...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...CDG/PM
000
FXUS62 KGSP 231837
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
237 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF MID AFTERNOON...A FEW SHOWERS HAVE POPPED UP QUICKLY NEAR THE
BLUE RIDGE. THESE SHOULD BE DRIVEN EASTWARD OVER THE FOOTHILLS AND
WESTERN PIEDMONT THROUGH LATE AFTERNOON. SATELLITE IMAGERY SHOWS
SOME ENHANCED CU OVER THE RIDGETOPS...SO ADDITIONAL DEVELOPMENT IS
POSSIBLE. THE CURRENT POP FCST...WITH THE HIGHEST VALUES E OF
I-77... STILL LOOKS OKAY. CANNOT RULE OUT ONE OR TWO SEVERE CELLS
GIVEN SUFFICIENT CAPE ON THE LATEST LAPS ANALYSIS AND SOME DCAPE AS
WELL...BUT NEITHER IS AS GOOD AS YESTERDAY. NE GEORGIA AND THE
UPSTATE WILL HAVE THE LEAST CHANCE OF PRECIP BECAUSE OF A LACK OF
TRIGGER.
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...MVFR CIG RESTRICTION SHOULD NOT LAST MORE THAN ONE OR TWO
HOURS AS THE BOUNDARY LAYER WARMS AND DEEPENS...LIFTING ANY CLOUD
BASES UP IN TO THE 035 TO 050 RANGE. THINK THAT AT LEAST A TEMPORARY
LOW CLOUD VFR CEILING WILL CONTINUE THROUGH THE AFTERNOON GIVEN
SUFFICIENT MOISTURE IN THE BOUNDARY LAYER. HAVE HELD ONTO A TWO HOUR
WINDOW OF THUNDERSTORMS PER THE 4KM WRF MODEL IN THE 21Z TO 23Z TIME
RANGE...BUT CONFIDENCE IS DROPPING. THE FRONT SHOULD FINALLY CROSS
THE REGION DURING THE MIDDLE PART OF THE EVENING WHICH WILL CLEAR
OUT THE LOW CLOUDS AND SHIFT THE WIND FROM SW TO NW...BY 04Z AT THE
LATEST. CONDITIONS SHOULD BE VFR FROM THAT POINT ONWARD. ON
FRIDAY...ONCE THE WINDS COME UP DURING MID MORNING...EXPECT FREQUENT
GUSTS FROM THE NW.
ELSEWHERE...SIMILAR CHANCES FOR MVFR CEILING UNTIL 20Z OR SO WHEN
THE BOUNDARY LAYER LIFTS THE CLOUD BASES ABOVE 030. OTHERWISE...
LESS OF A CHANCE FOR CONVECTIVE ACTIVITY. ONLY KHKY WARRANTS A
VICINITY THUNDERSTORM FOR THE TIME BEING. EXPECT VFR CONDITIONS
AFTER FRONTAL PASSAGE...WHICH SHOULD BE LATE AFTERNOON TO EARLY
EVENING. SOME UPSLOPE SHOWERS COULD OCCUR ALONG THE TN BORDER...BUT
THIS IS NOT EXPECTED TO AFFECT KAVL. WINDS SHOULD BE STRONG AND
GUSTY FROM THE NW ON FRIDAY.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 85% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% MED 79% HIGH 81% HIGH 95%
KHKY HIGH 89% HIGH 100% HIGH 83% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% 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...LEV
NEAR TERM...PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...PM
000
FXUS62 KGSP 231758
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
158 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF EARLY AFTERNOON...MOST OF THE CONVECTIVE DEVELOPMENT HAS TAKEN
PLACE JUST EAST OF THE CLT METRO AREA. OTHERWISE...KGSP RADAR IS
NEARLY QUIET ACROSS THE FCST AREA. SEEING SOME ENHANCEMENT TO THE CU
NEAR THE BLUE RIDGE...SO AM NOT READY TO GIVE UP ON THE PRECIP
CHANCES FOR THE AFTERNOON...PER THE OLD RUN OF THE 4KM WRF. TEMPS
LOOK OKAY.
PREVIOUS DISCUSSION...
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 145 PM THURSDAY...THE 06Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
BUILDS OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK IMPULSES
TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A RATHER
UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS THE
RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUN.
HPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR OFFICIAL/GFS/ECM WHICH WOULD PUT
A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...MVFR CIG RESTRICTION SHOULD NOT LAST MORE THAN ONE OR TWO
HOURS AS THE BOUNDARY LAYER WARMS AND DEEPENS...LIFTING ANY CLOUD
BASES UP IN TO THE 035 TO 050 RANGE. THINK THAT AT LEAST A TEMPORARY
LOW CLOUD VFR CEILING WILL CONTINUE THROUGH THE AFTERNOON GIVEN
SUFFICIENT MOISTURE IN THE BOUNDARY LAYER. HAVE HELD ONTO A TWO HOUR
WINDOW OF THUNDERSTORMS PER THE 4KM WRF MODEL IN THE 21Z TO 23Z TIME
RANGE...BUT CONFIDENCE IS DROPPING. THE FRONT SHOULD FINALLY CROSS
THE REGION DURING THE MIDDLE PART OF THE EVENING WHICH WILL CLEAR
OUT THE LOW CLOUDS AND SHIFT THE WIND FROM SW TO NW...BY 04Z AT THE
LATEST. CONDITIONS SHOULD BE VFR FROM THAT POINT ONWARD. ON
FRIDAY...ONCE THE WINDS COME UP DURING MID MORNING...EXPECT FREQUENT
GUSTS FROM THE NW.
ELSEWHERE...SIMILAR CHANCES FOR MVFR CEILING UNTIL 20Z OR SO WHEN
THE BOUNDARY LAYER LIFTS THE CLOUD BASES ABOVE 030. OTHERWISE...
LESS OF A CHANCE FOR CONVECTIVE ACTIVITY. ONLY KHKY WARRANTS A
VICINITY THUNDERSTORM FOR THE TIME BEING. EXPECT VFR CONDITIONS
AFTER FRONTAL PASSAGE...WHICH SHOULD BE LATE AFTERNOON TO EARLY
EVENING. SOME UPSLOPE SHOWERS COULD OCCUR ALONG THE TN BORDER...BUT
THIS IS NOT EXPECTED TO AFFECT KAVL. WINDS SHOULD BE STRONG AND
GUSTY FROM THE NW ON FRIDAY.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 85% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% MED 79% HIGH 81% HIGH 95%
KHKY HIGH 89% HIGH 100% HIGH 83% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% 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...JAT/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...PM
000
FXUS62 KGSP 231340
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
940 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF MID MORNING...THE KGSP RADAR SHOWED A PATCH OF VERY LIGHT RAIN
MOVING ACROSS METRO CLT AND SOME OTHER SHOWER ACTIVITY SKIRTING THE
NRN MOUNTAINS. THE POP FOR THE NEXT HOUR OR TWO WAS ADJUSTED
ACCORDINGLY. AS FOR THE REST OF THE DAY...THE LATEST RUNS OF THE
CONVECTION ALLOWING MODELS ARE NOT AS EXCITED COMPARED TO YESTERDAY.
THINK THE MOST LIKELY SCENARIO WILL BE FOR SCATTERED SHOWERS
DEVELOPING OVER THE PIEDMONT DURING THE MIDDLE PART OF THE DAY AND
THEN MOVING OFF TO THE EAST BEFORE BECOMING MORE NUMEROUS. THESE
MODELS WERE VERY GOOD YESTERDAY. WITH THAT IN MIND...HAVE LOWERED
THE EXPECTATIONS FOR THIS AFTERNOON AND TRIMMED POP BACK TO THE
CHANCE RANGE ACROSS ALL BUT THE NORTHERNMOST ZONES. TEMP TRENDS WERE
ALSO ADJUSTED DOWNWARD FOR THE MORNING BECAUSE OF THE EXTENSIVE
CONVECTIVE DEBRIS CLOUDS.
PREVIOUS DISCUSSION...
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AT KCLT...MVFR CIG RESTRICTION HAS FINALLY DEVELOPED AND WILL BE
CARRIED INITIALLY. THE LATEST GUIDANCE SUPPORTS VFR...SO THE
RESTRICTION WILL ONLY BE TEMPORARY FOR NOW. SW WINDS WILL APPROACH
10 KNOTS THIS MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE
RESTRICTIONS IS EXPECTED THIS AFTERNOON AS A COLD FRONT MOVES
THROUGH FROM THE W... AND ANOTHER APPROACHES FROM THE NW. CONVECTION
WILL MOVE OFF TO THE EAST BY THIS EVENING....WHILE SW WINDS VEER TO
NW AND BECOME GUSTY. MODEL TIME HEIGHTS SUGGEST THE A LOW VFR CIG
WILL PERSIST INTO THIS EVENING.
ELSEWHERE...RESTRICTIONS WILL END BY MID MORNING AS WINDS COME UP
FROM THE SW IN THE FOOTHILLS AND NW IN THE MOUNTAINS. ADDITIONAL
CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY BETWEEN A
DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING FROM THE
NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE FOOTHILLS AND
BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE EVENING.
OVERNIGHT PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
BORDERING TN THIS EVENING IN NW UPSLOPE FLOW.
OUTLOOK...VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-13Z
KCLT HIGH 97% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 95% HIGH 100% HIGH 95% MED 79%
KHKY HIGH 88% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 97% 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...JAT/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 231144
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
744 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1155 UTC UPDATE...POPS HAVE BEEN INCREASED IN THE NORTHERN NC
MOUNTAINS AND SOUTHEAST OF KCLT PER RADAR TRENDS.
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AT KCLT...MVFR CIG RESTRICTION HAS FINALLY DEVELOPED AND WILL BE
CARRIED INITIALLY. THE LATEST GUIDANCE SUPPORTS VFR...SO THE
RESTRICTION WILL ONLY BE TEMPORARY FOR NOW. SW WINDS WILL APPROACH
10 KNOTS THIS MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE
RESTRICTIONS IS EXPECTED THIS AFTERNOON AS A COLD FRONT MOVES
THROUGH FROM THE W... AND ANOTHER APPROACHES FROM THE NW. CONVECTION
WILL MOVE OFF TO THE EAST BY THIS EVENING....WHILE SW WINDS VEER TO
NW AND BECOME GUSTY. MODEL TIME HEIGHTS SUGGEST THE A LOW VFR CIG
WILL PERSIST INTO THIS EVENING.
ELSEWHERE...RESTRICTIONS WILL END BY MID MORNING AS WINDS COME UP
FROM THE SW IN THE FOOTHILLS AND NW IN THE MOUNTAINS. ADDITIONAL
CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY BETWEEN A
DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING FROM THE
NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE FOOTHILLS AND
BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE EVENING.
OVERNIGHT PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
BORDERING TN THIS EVENING IN NW UPSLOPE FLOW.
OUTLOOK...VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 87% HIGH 98% HIGH 100% HIGH 100%
KGSP HIGH 87% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 94% HIGH 100% HIGH 98% HIGH 83%
KHKY HIGH 83% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 92% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 92% 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...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 231014
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
614 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1015 UTC UPDATE...VISIBILITY HAS BEEN UPDATED FROM OBSERVATIONS...
RESULTING IN LESS FOG COVERAGE...AND GREATER VISIBILITY VALUES.
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
10-16Z 16-22Z 22-04Z 04-10Z
KCLT HIGH 92% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 90% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 90% HIGH 100% HIGH 100% HIGH 86%
KHKY HIGH 90% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 94% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 92% 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...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 230938
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
538 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
0930 UTC UPDATE...POPS HAVE BEEN ADJUSTED PER RADAR TRENDS...WITH
GREATER COVERAGE IN THE SC PIEDMONT.
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-09Z
KCLT HIGH 94% HIGH 98% HIGH 100% HIGH 100%
KGSP HIGH 86% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 84% HIGH 100% HIGH 100% HIGH 90%
KHKY HIGH 87% HIGH 100% HIGH 100% HIGH 100%
KGMU MED 79% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 90% 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...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 230751
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
351 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 86% HIGH 94% HIGH 100% HIGH 100%
KGSP MED 78% HIGH 98% HIGH 100% HIGH 100%
KAVL MED 79% HIGH 94% HIGH 100% HIGH 92%
KHKY MED 71% HIGH 92% HIGH 100% HIGH 100%
KGMU MED 67% HIGH 97% HIGH 100% HIGH 100%
KAND MED 76% HIGH 97% 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...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 230521
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
121 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
0500 UTC UPDATE...POPS WERE REALIGNED TO CONCUR WITH RADAR
TRENDS...MOVING A LINE OF CONVECTION ACROSS INTERSTATE 77 OVER THE
NET FEW HOURS...ANOTHER CLUSTER OF STORMS ACROSS THE UPPER SAVANNAH
RIVER VALLEY...AND A THIRD GROUP OF STORMS FROM THE GA MOUNTAINS
INTO SC. WINDS WERE UPDATED WITH A BLEND OF THE LATEST ADJMAV AND
NAM...FAVORING THE LATER FOR HIGHER WINDS IN THE MOUNTAINS.
VISIBILITY WAS UPDATED FORM OBSERVATIONS AND A BLEND OF THE ADJMAV
AND ADJMET...LOWERED SLIGHTLY TOWARD THE LAMP GUIDANCE.
AS OF 1045 PM...BROKEN MULTICELL LINE OF THUNDERSTORMS CONTINUES TO
MOVE TO THE EAST NORTHEAST ACROSS THE UPSTATE IN ASSOCIATION WITH
CONVERGENCE NEAR FRONTAL BOUNDARY. ELSEWHERE...DISCRETE PULSE
SHOWERS AND THUNDERSTORMS WERE PRESENT ACROSS PORTIONS OF THE NORTH
CAROLINA FOOTHILLS/PIEDMONT. THE MAIN THREATS WITH ANY OF THESE
THUNDERSTORMS ARE BRIEF HEAVY RAINFALL...LARGE HAIL...DAMAGING
WINDS...AND FREQUENT CLOUD TO GROUND LIGHTNING. AS FOR THE
FCST...THE ACTIVITY CURRENTLY EXTENDING ACROSS THE WESTERN CWFA
SHOULD MOVE EASTWARD ACROSS THE CWFA GRADUALLY DIMINISHING IN
INTENSITY AS INSTABILITY WANES. GENERALLY CHANGED POPS TO REFLECT
THIS WAVE OF ACTIVITY BEING FOLLOWED BY MUCH LOWER POPS IN SCHC TO
LOW CHC RANGE DUE TO CONTINUED PRESENCE OF UPSTREAM ACTIVITY.
ADJUSTED TEMPERATURE TRENDS FURTHER BY LOWERING TEMPS ACROSS THE
NORTH CAROLINA PIEDMONT DUE TO OUTFLOW BOUNDARIES FROM EARLIER
CONVECTION SPREADING ACROSS THIS REGION.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF 800 PM...TOUCHED UP EVENING TEMP TRENDS...WHICH HAVE BEEN
IMPACTED GREATLY BY THUNDERSTORMS AND THEIR COOL OUTFLOW. RADAR
INDICATES SEVERAL BOUNDARIES SPREADING ACROSS THE PIEDMONT...WHERE
TEMPS REMAIN IN THE MID TO UPPER 70S. THINK THESE WILL BE IMPACTED
BY BOTH DIURNAL COOLING AS WELL AS THE OUTFLOW. LAMP TEMPS SEEM TO
REFLECT THE CURRENT SITUATION FAIRLY WELL AND THESE ARE IN DECENT
AGREEMENT WITH LATE EVENING TEMPS...SO NO CHANGES MADE OTHER THAN TO
UPDATE FIRST FEW HRS.
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
A FEW DEGREES COOLER.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 84% HIGH 90% HIGH 100% HIGH 100%
KGSP MED 79% HIGH 88% HIGH 100% HIGH 100%
KAVL MED 70% HIGH 88% HIGH 100% HIGH 97%
KHKY LOW 56% HIGH 83% HIGH 100% HIGH 100%
KGMU MED 73% HIGH 83% HIGH 100% HIGH 100%
KAND MED 69% HIGH 94% 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...SBK
NEAR TERM...CDG/JAT/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...JAT
000
FXUS62 KGSP 230248
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1048 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 1045 PM...BROKEN MULTICELL LINE OF THUNDERSTORMS CONTINUES TO
MOVE TO THE EAST NORTHEAST ACROSS THE UPSTATE IN ASSOCIATION WITH
CONVERGENCE NEAR FRONTAL BOUNDARY. ELSEWHERE...DISCRETE PULSE
SHOWERS AND THUNDERSTORMS WERE PRESENT ACROSS PORTIONS OF THE NORTH
CAROLINA FOOTHILLS/PIEDMONT. THE MAIN THREATS WITH ANY OF THESE
THUNDERSTORMS ARE BRIEF HEAVY RAINFALL...LARGE HAIL...DAMAGING
WINDS...AND FREQUENT CLOUD TO GROUND LIGHTNING. AS FOR THE
FCST...THE ACTIVITY CURRENTLY EXTENDING ACROSS THE WESTERN CWFA
SHOULD MOVE EASTWARD ACROSS THE CWFA GRADUALLY DIMINISHING IN
INTENSITY AS INSTABILITY WANES. GENERALLY CHANGED POPS TO REFLECT
THIS WAVE OF ACTIVITY BEING FOLLOWED BY MUCH LOWER POPS IN SCHC TO
LOW CHC RANGE DUE TO CONTINUED PRESENCE OF UPSTREAM ACTIVITY.
ADJUSTED TEMPERATURE TRENDS FURTHER BY LOWERING TEMPS ACROSS THE
NORTH CAROLINA PIEDMONT DUE TO OUTFLOW BOUNDARIES FROM EARLIER
CONVECTION SPREADING ACROSS THIS REGION.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF 800 PM...TOUCHED UP EVENING TEMP TRENDS...WHICH HAVE BEEN
IMPACTED GREATLY BY THUNDERSTORMS AND THEIR COOL OUTFLOW. RADAR
INDICATES SEVERAL BOUNDARIES SPREADING ACROSS THE PIEDMONT...WHERE
TEMPS REMAIN IN THE MID TO UPPER 70S. THINK THESE WILL BE IMPACTED
BY BOTH DIURNAL COOLING AS WELL AS THE OUTFLOW. LAMP TEMPS SEEM TO
REFLECT THE CURRENT SITUATION FAIRLY WELL AND THESE ARE IN DECENT
AGREEMENT WITH LATE EVENING TEMPS...SO NO CHANGES MADE OTHER THAN TO
UPDATE FIRST FEW HRS.
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
A FEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AT KCLT...PREVAILING VFR THIS EVENING BUT THERE REMAINS THE
POSSIBILITY OF RESTRICTIONS FROM THUNDERSTORMS. STABILIZING OUTFLOW
FROM UPSTREAM TS MAY PUT A STOP TO CONVECTION BUT ITS LEADING EDGE
COULD BE THE FOCUS FOR NEW DEVELOPMENT FOR A TIME TONIGHT. INCLUDED
A TEMPO THRU 04Z FOR MVFR TSRA...BUT WILL CLOSELY WATCH TRENDS OVER
NEXT COUPLE OF HOURS AND MAY BE ABLE TO REMOVE IT. PROFILES BECOME
INCREASINGLY MOIST OVERNIGHT AHEAD OF FRONTAL BOUNDARY. PER MODEL RH
FIELDS EXPECT A LOWERING TO SOLID MVFR LATE...WITH SUFFICIENT
ELEVATED INSTABILITY TO WARRANT ANOTHER TEMPO FOR TSRA. LULL IN
ACTIVITY EXPECTED NEAR DAYBREAK WITH LOW MVFR PERSISTING UNTIL
MIXING GETS UNDERWAY MID MORNING. DECENT THUNDER CHANCES AGAIN WITH
DIURNAL HEATING WARRANTING -TSRA BUT VFR.
ELSEWHERE...CONVECTION CONTINUES THIS EVENING ACROSS MAINLY THE
MTNS/FOOTHILLS. MUCH OF THE PIEDMONT WILL BE STABILIZED BY TS
OUTFLOW WITH UPSTREAM ACTIVITY LIKELY TO DIMINISH TOO QUICKLY WITH
LOSS OF HEATING TO HAVE EFFECTS. OVERNIGHT FROPA WILL BRING BACK TS
OR SHRA CHANCES. HANDLED THIS WITH VCTS OR TEMPOS AS APPROPRIATE.
PLENTY OF MOISTURE TO THINK RESTRICTIVE CIGS WILL DEVELOP BEHIND THE
FRONT AND PERSIST THRU DAYBREAK. DIURNAL CU WILL QUICKLY GROW IN
UNSTABLE ATMOSPHERE BY LATE MORNING. CU BASES EXPECTED TO BE WELL
WITHIN VFR TERRITORY...WITH SOME LOW TS CHANCES ALSO THROUGH PEAK
HEATING.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT MED 60% HIGH 86% HIGH 80% HIGH 100%
KGSP LOW 58% MED 72% HIGH 82% HIGH 100%
KAVL MED 71% HIGH 97% HIGH 98% HIGH 100%
KHKY LOW 45% MED 77% HIGH 91% HIGH 100%
KGMU LOW 58% MED 73% HIGH 100% HIGH 100%
KAND MED 65% MED 76% 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...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/WIMBERLEY
000
FXUS62 KGSP 230022
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
822 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 800 PM...TOUCHED UP EVENING TEMP TRENDS...WHICH HAVE BEEN
IMPACTED GREATLY BY THUNDERSTORMS AND THEIR COOL OUTFLOW. RADAR
INDICATES SEVERAL BOUNDARIES SPREADING ACROSS THE PIEDMONT...WHERE
TEMPS REMAIN IN THE MID TO UPPER 70S. THINK THESE WILL BE IMPACTED
BY BOTH DIURNAL COOLING AS WELL AS THE OUTFLOW. LAMP TEMPS SEEM TO
REFLECT THE CURRENT SITUATION FAIRLY WELL AND THESE ARE IN DECENT
AGREEMENT WITH LATE EVENING TEMPS...SO NO CHANGES MADE OTHER THAN TO
UPDATE FIRST FEW HRS.
AS OF 430 PM...INCREASED POPS ACROSS THE UPSTATE OF SOUTH CAROLINA
AND THE PIEDMONT OF NORTH CAROLINA DURING THE OVERNIGHT HOURS AS
SHORT TERM CONVECTIVE MODEL GUIDANCE CONTINUES WIDESPREAD CONVECTION
ACROSS THE ABOVE MENTIONED REGIONS THROUGH 10Z THURSDAY. ALSO
TOUCHED UP SKY AND TEMP GRIDS. OTHERWISE...NO OTHER CHANGES WERE
MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
A FEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
AT KCLT...PREVAILING VFR THIS EVENING BUT THERE REMAINS THE
POSSIBILITY OF RESTRICTIONS FROM THUNDERSTORMS. STABILIZING OUTFLOW
FROM UPSTREAM TS MAY PUT A STOP TO CONVECTION BUT ITS LEADING EDGE
COULD BE THE FOCUS FOR NEW DEVELOPMENT FOR A TIME TONIGHT. INCLUDED
A TEMPO THRU 04Z FOR MVFR TSRA...BUT WILL CLOSELY WATCH TRENDS OVER
NEXT COUPLE OF HOURS AND MAY BE ABLE TO REMOVE IT. PROFILES BECOME
INCREASINGLY MOIST OVERNIGHT AHEAD OF FRONTAL BOUNDARY. PER MODEL RH
FIELDS EXPECT A LOWERING TO SOLID MVFR LATE...WITH SUFFICIENT
ELEVATED INSTABILITY TO WARRANT ANOTHER TEMPO FOR TSRA. LULL IN
ACTIVITY EXPECTED NEAR DAYBREAK WITH LOW MVFR PERSISTING UNTIL
MIXING GETS UNDERWAY MID MORNING. DECENT THUNDER CHANCES AGAIN WITH
DIURNAL HEATING WARRANTING -TSRA BUT VFR.
ELSEWHERE...CONVECTION CONTINUES THIS EVENING ACROSS MAINLY THE
MTNS/FOOTHILLS. MUCH OF THE PIEDMONT WILL BE STABILIZED BY TS
OUTFLOW WITH UPSTREAM ACTIVITY LIKELY TO DIMINISH TOO QUICKLY WITH
LOSS OF HEATING TO HAVE EFFECTS. OVERNIGHT FROPA WILL BRING BACK TS
OR SHRA CHANCES. HANDLED THIS WITH VCTS OR TEMPOS AS APPROPRIATE.
PLENTY OF MOISTURE TO THINK RESTRICTIVE CIGS WILL DEVELOP BEHIND THE
FRONT AND PERSIST THRU DAYBREAK. DIURNAL CU WILL QUICKLY GROW IN
UNSTABLE ATMOSPHERE BY LATE MORNING. CU BASES EXPECTED TO BE WELL
WITHIN VFR TERRITORY...WITH SOME LOW TS CHANCES ALSO THROUGH PEAK
HEATING.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT MED 60% MED 78% MED 79% HIGH 96%
KGSP LOW 57% MED 65% MED 73% HIGH 100%
KAVL HIGH 80% HIGH 94% HIGH 94% HIGH 100%
KHKY LOW 58% MED 60% HIGH 82% HIGH 100%
KGMU LOW 57% MED 68% HIGH 91% HIGH 100%
KAND MED 65% HIGH 86% HIGH 91% 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...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/WIMBERLEY
000
FXUS62 KGSP 222355
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
755 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 430 PM...INCREASED POPS ACROSS THE UPSTATE OF SOUTH CAROLINA
AND THE PIEDMONT OF NORTH CAROLINA DURING THE OVERNIGHT HOURS AS
SHORT TERM CONVECTIVE MODEL GUIDANCE CONTINUES WIDESPREAD CONVECTION
ACROSS THE ABOVE MENTIONED REGIONS THROUGH 10Z THURSDAY. ALSO
TOUCHED UP SKY AND TEMP GRIDS. OTHERWISE...NO OTHER CHANGES WERE
MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
AFEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AT KCLT...PREVAILING VFR THIS EVENING BUT THERE REMAINS THE
POSSIBILITY OF RESTRICTIONS FROM THUNDERSTORMS. STABILIZING OUTFLOW
FROM UPSTREAM TS MAY PUT A STOP TO CONVECTION BUT ITS LEADING EDGE
COULD BE THE FOCUS FOR NEW DEVELOPMENT FOR A TIME TONIGHT. INCLUDED
A TEMPO THRU 04Z FOR MVFR TSRA...BUT WILL CLOSELY WATCH TRENDS OVER
NEXT COUPLE OF HOURS AND MAY BE ABLE TO REMOVE IT. PROFILES BECOME
INCREASINGLY MOIST OVERNIGHT AHEAD OF FRONTAL BOUNDARY. PER MODEL RH
FIELDS EXPECT A LOWERING TO SOLID MVFR LATE...WITH SUFFICIENT
ELEVATED INSTABILITY TO WARRANT ANOTHER TEMPO FOR TSRA. LULL IN
ACTIVITY EXPECTED NEAR DAYBREAK WITH LOW MVFR PERSISTING UNTIL
MIXING GETS UNDERWAY MID MORNING. DECENT THUNDER CHANCES AGAIN WITH
DIURNAL HEATING WARRANTING -TSRA BUT VFR.
ELSEWHERE...CONVECTION CONTINUES THIS EVENING ACROSS MAINLY THE
MTNS/FOOTHILLS. MUCH OF THE PIEDMONT WILL BE STABILIZED BY TS
OUTFLOW WITH UPSTREAM ACTIVITY LIKELY TO DIMINISH TOO QUICKLY WITH
LOSS OF HEATING TO HAVE EFFECTS. OVERNIGHT FROPA WILL BRING BACK TS
OR SHRA CHANCES. HANDLED THIS WITH VCTS OR TEMPOS AS APPROPRIATE.
PLENTY OF MOISTURE TO THINK RESTRICTIVE CIGS WILL DEVELOP BEHIND THE
FRONT AND PERSIST THRU DAYBREAK. DIURNAL CU WILL QUICKLY GROW IN
UNSTABLE ATMOSPHERE BY LATE MORNING. CU BASES EXPECTED TO BE WELL
WITHIN VFR TERRITORY...WITH SOME LOW TS CHANCES ALSO THROUGH PEAK
HEATING.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT MED 60% MED 78% MED 79% HIGH 96%
KGSP LOW 57% MED 65% MED 73% HIGH 100%
KAVL HIGH 80% HIGH 94% HIGH 94% HIGH 100%
KHKY LOW 58% MED 60% HIGH 82% HIGH 100%
KGMU LOW 57% MED 68% HIGH 91% HIGH 100%
KAND MED 65% HIGH 86% HIGH 91% 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...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/WIMBERLEY
000
FXUS62 KGSP 222106
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
506 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 430 PM...INCREASED POPS ACROSS THE UPSTATE OF SOUTH CAROLINA
AND THE PIEDMONT OF NORTH CAROLINA DURING THE OVERNIGHT HOURS AS
SHORT TERM CONVECTIVE MODEL GUIDANCE CONTINUES WIDESPREAD CONVECTION
ACROSS THE ABOVE MENTIONED REGIONS THROUGH 10Z THURSDAY. ALSO
TOUCHED UP SKY AND TEMP GRIDS. OTHERWISE...NO OTHER CHANGES WERE
MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
AFEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT FOR 21Z UPDATE...THINK CONDITIONS WILL REMAIN VFR INTO THE
EARLY EVENING...WITH BKN CLOUD BASES AROUND THE 035 TO 045 RANGE.
THE LATEST GUIDANCE...INCLUDING THE CONVECTIVE MODELS...IS FOCUSING
MORE ON THE MID TO LATE EVENING ACROSS THE NC PIEDMONT FOR WHEN A
BROKEN BAND OF STORMS WILL MOVE THROUGH. REMOVED PREVIOUS PROB30 AND
WENT WITH A 4HR TEMPO GROUP FOR TSRA WITH MVFR VISB. THE FRONT
SHOULD STAY WEST OF THE TERMINAL THROUGH EARLY AFTERNOON AND WILL
SERVE AS A TRIGGER FOR NEW DEVELOPMENT BY LATE MORNING
THURSDAY...THUS ANOTHER PROB30 GROUP TOWARD THE END OF THE PERIOD.
AS A RESULT...WIND DIRECTION SHOULD REMAIN S TO SW.
ELSEWHERE...VFR FOR THE TIME BEING. CONVECTIVE CLOUD BASES SHOULD
REMAIN IN THE 035 TO 050 RANGE...MAINLY FEW TO SCT...AND THEN SHOULD
DROP INTO THE MVFR RANGE THIS EVENING AS CONVECTION BECOMES MORE
NUMEROUS. THE FRONT WILL PROBABLY MAKE IT INTO THE MTNS THURSDAY
MORNING SO THE WIND AT KAVL WAS SHIFTED TO NW. ANOTHER ROUND OF
SHOWERS AND STORMS IS POSSIBLE OVER NC THURSDAY LATE IN THE PERIOD.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 100% HIGH 87% HIGH 88% MED 79%
KGSP HIGH 92% MED 71% HIGH 91% HIGH 100%
KAVL MED 77% HIGH 81% HIGH 86% HIGH 100%
KHKY HIGH 80% LOW 56% MED 72% HIGH 83%
KGMU HIGH 92% MED 69% HIGH 88% HIGH 100%
KAND HIGH 93% MED 74% HIGH 88% 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...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/PM/WIMBERLEY
000
FXUS62 KGSP 221845
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
245 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
AFEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...THINK CONDITIONS WILL REMAIN VFR INTO THE EARLY
EVENING...WITH SCT CLOUD BASES AROUND THE 035 TO 045 RANGE. THE
LATEST GUIDANCE...INCLUDING THE CONVECTIVE MODELS...IS FOCUSING MORE
ON THE MID TO LATE EVENING ACROSS THE NC PIEDMONT FOR WHEN A BROKEN
BAND OF STORMS WILL MOVE THROUGH. WILL CARRY A PROB30 FOR THIS IN
THE 03Z TO 06Z TIME FRAME. EXPECT ADJUSTMENTS TO THE PROB AND MIGHT
HAVE TO INCLUDE A TEMPO LATER IN THE DAY. WITH COOLING...THE CLOUD
BASES SHOULD FALL INTO MVFR RANGE LATE THIS EVENING AND STAY THERE
THROUGH EARLY AFTERNOON ON THURSDAY. FOG COULD BECOME A PROBLEM
AROUND DAYBREAK IF SIGNIFICANT RAIN HAPPENS LATE TONIGHT.
OTHERWISE...THE VSBY WAS KEPT ABOVE 5 MILES. THE FRONT SHOULD STAY
WEST OF THE TERMINAL THROUGH EARLY AFTERNOON AND WILL SERVE AS A
TRIGGER FOR NEW DEVELOPMENT BY LATE MORNING THURSDAY...THUS ANOTHER
PROB30 GROUP TOWARD THE END OF THE PERIOD. AS A RESULT...WIND
DIRECTION SHOULD REMAIN S TO SW.
ELSEWHERE...VFR FOR THE TIME BEING. CONVECTIVE CLOUD BASES SHOULD
REMAIN IN THE 035 TO 050 RANGE...MAINLY FEW TO SCT...AND THEN SHOULD
DROP INTO THE MVFR RANGE THIS EVENING AS CONVECTION BECOMES MORE
NUMEROUS. THE FRONT WILL PROBABLY MAKE IT INTO THE MTNS THURSDAY
MORNING SO THE WIND AT KAVL WAS SHIFTED TO NW. ANOTHER ROUND OF
SHOWERS AND STORMS IS POSSIBLE OVER NC THURSDAY LATE IN THE PERIOD.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 86% HIGH 100% HIGH 86% HIGH 90%
KGSP HIGH 100% MED 79% HIGH 87% HIGH 97%
KAVL HIGH 93% MED 77% HIGH 81% HIGH 97%
KHKY HIGH 93% MED 73% LOW 54% HIGH 80%
KGMU HIGH 100% MED 79% HIGH 83% HIGH 94%
KAND HIGH 100% HIGH 80% HIGH 82% HIGH 95%
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...SBK
NEAR TERM...PM
SHORT TERM...TS
LONG TERM...SBK
AVIATION...PM
000
FXUS62 KGSP 221756
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
156 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF EARLY AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS
HAD DEVELOPED ALONG THE BLUE RIDGE IN NC FROM I-40 NWD...WITH OTHER
STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY DIFFERENTIAL
HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS ACROSS THE MTNS
THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING EAST OVER THE
FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN ADJUSTED
ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL AND
DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
PREVIOUS DISCUSSION...
AT 300 AM EST WEDNESDAY...AN UPPER TROUGH AXIS WILL SLOWLY CROSS THE
MS RIVER VALLEY TODAY AND TONIGHT. A SHORTWAVE ROUNDING THIS UPPER
TROUGH WILL REACH THE SOUTHERN APPALACHIANS THIS EVENING...CROSSING
OUR AREA OVERNIGHT. A WEAKENING COLD FRONT WILL APPROACH OUR AREA
FROM THE WEST TODAY...PRECEDED BY A BAND OF GULF MOISTURE...WHILE
ATLANTIC MOISTURE MOVES NORTH INTO THE PIEDMONT. THESE MOISTURE BAND
CONVERGE OVER OUR AREA TONIGHT. THE FRONT AND MOISTURE ALONG IT
REACH THE INTERSTATE 77 CORRIDOR BY THURSDAY MORNING. ALTHOUGH
INSTABILITY WILL PEAK DURING THE DAYLIGHT HOURS...WINDS SHEAR WILL
INCREASE THIS EVENING...OPENING A WIDER WINDOW FOR SEVERE WEATHER
POTENTIAL. THE MOISTENING AIR MASS WILL SUPPORT HEAVIER RAINFALL
WITH TIME. STEERING FLOW WILL INITIALLY MOVE CELLS INTO THE BLUE
RIDGE ESCARPMENT...BUT BY THE TIME THE BEST MOISTURE ARRIVES...CELL
MOVEMENT SHOULD BE MORE PARALLEL TO THE HIGHER TERRAIN. THIS WILL
LIMIT PRECIPITATION ACCUMULATION...AND NO LARGE SCALE HYDROLOGICAL
PROBLEMS ARE FORESEEN AT THIS TIME. TEMPERATURES WILL RUN A CATEGORY
OR TWO ABOVE NORMAL IN WARM ADVECTION.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM WEDNESDAY...SHORT WAVES MOVING THRU AN UPPER TROF PUSH
THE TROF AXIS TOWARD THU THEN INTO THE AREA THU NITE. AT THE SFC...
A PRE-FRONTAL TROF STARTS THE DAY OVER THE AREA WITH A COLD FRONT TO
OUR WEST. THIS FRONT JUMPS INTO THE TROF BY THE END OF THE DAY AND
MOVES EAST OF THE AREA THU NITE. THIS SETS UP TWO AREAS OF FORCING.
ONE OVER THE ERN CWFA ALONG THE TROF AND OVER THE MTNS AHEAD OF THE
FRONT. NE GA AND MUCH OF THE UPSTATE WILL BE BETWEEN THESE 2 AREAS.
THEREFORE...HAVE PUT THE HIGHEST POP OVER THE AREAS WITH BEST
FORCING...BUT DID KEEP LOW CHC POP OVER NE GA AND THE UPSTATE AS
THERE WILL BE WEAK INSTABILITY IN PLACE. BEST INSTABILITY AND SHEAR
WILL BE EAST OF THE AREA...SO DO NOT EXPECT ANY SIGNIFICANT COVERAGE
OF SVR STORMS. PRECIP CHC DIMINISHES OUTSIDE OF THE MTNS DURING THE
EVENING AS THE FRONT MOVES EAST. HOWEVER...SCT SHRA WILL LINGER OVER
THE NC MTNS IN THE DEVELOPING NW FLOW AND CONTINUED LOW LEVEL
MOISTURE. HIGHS THU AROUND 5 DEGREES ABOVE NORMAL WITH LOWS A COUPLE
OF DEGREES ABOVE NORMAL THU NITE.
THE UPPER TROF AXIS MOVES EAST OF THE AREA FRI WITH NWLY FLOW
REMAINING IN PLACE FRI NITE...WHILE SFC HIGH PRESSURE SLOWLY BUILDS
TOWARD THE AREA. ANY LINGERING NW FLOW SHRA END BY AFTERNOON. THE
BIGGER STORIES WILL BE THE WINDS AND COLD AIR MASS MOVING IN. EXPECT
WINDY CONDITIONS TO DEVELOP AS MIXING TAPS SIGNIFICANT LOW LEVEL
WINDS. THAT SAID...IT LOOKS LIKE WINDS AND GUSTS WILL REMAIN BELOW
WIND ADV LEVELS. HIGHS FRI WILL BE 5 TO 10 DEGREES BELOW NORMAL
WHILE LOWS FRI NITE END UP 10 TO 15 DEGREES BELOW NORMAL. RIGHT NOW
IT LOOKS LIKE WINDS WILL REMAIN TOO STRONG FOR ANY SIGNIFICANT FROST
FORMATION OVER THE NC MTNS. HOWEVER...WILL HAVE TO KEEP AN EYE ON
THIS AS TEMPS APPROACH FROSTY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 355 AM WEDNESDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
THRU THE MEDIUM RANGE. HOWEVER...THERE ARE SOME DETAIL DIFFERENCES.
NWLY UPPER FLOW REMAINS OVER THE AREA SAT AND SUN AS THE CWFA WILL
BE BETWEEN A TROF TO OUR EAST AND A RIDGE TO OUR WEST. THE FLOW
BECOMES ZONAL FOR MONDAY WITH WEAK RIDGING TUE. ALL THIS TIME...
SERIES OF SHORT WAVES MOVE THRU THE FLOW AND ACROSS THE AREA. AT THE
SFC...HIGH PRESSURE RIDGES IN FROM THE NW...BUT IS SPLIT BY A WEAK
BACK DOOR COLD FRONT. THIS FRONT REMAINS OVER OR NEAR THE AREA MON
AND TUE. PRECIP ACTIVATES ALONG THE FRONT FROM TIME TO TIME AS THE
WAVES MOVE OVER. HOWEVER...THE ECMWF IS MUCH MORE WIDESPREAD WITH
PRECIP THAN THE GFS. FOR NOW...HAVE FOLLOWED NATIONAL GUIDANCE AND
KEEP PRECIP LIMITED TO SLIGHT CHC XCPT ACROSS THE NRN MTNS FROM MON
NITE ON. HIGHS AROUND 5 DEGREES BELOW NORMAL SAT AND SUN...NEAR
NORMAL MON...THEN ABOUT 5 DEGREES ABOVE NORMAL TUE. LOWS 5 TO 10
DEGREES BELOW NORMAL SAT NITE...NEAR NORMAL SUN NITE...THEN A LITTLE
ABOVE NORMAL MON NITE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...THINK CONDITIONS WILL REMAIN VFR INTO THE EARLY
EVENING...WITH SCT CLOUD BASES AROUND THE 035 TO 045 RANGE. THE
LATEST GUIDANCE...INCLUDING THE CONVECTIVE MODELS...IS FOCUSING MORE
ON THE MID TO LATE EVENING ACROSS THE NC PIEDMONT FOR WHEN A BROKEN
BAND OF STORMS WILL MOVE THROUGH. WILL CARRY A PROB30 FOR THIS IN
THE 03Z TO 06Z TIME FRAME. EXPECT ADJUSTMENTS TO THE PROB AND MIGHT
HAVE TO INCLUDE A TEMPO LATER IN THE DAY. WITH COOLING...THE CLOUD
BASES SHOULD FALL INTO MVFR RANGE LATE THIS EVENING AND STAY THERE
THROUGH EARLY AFTERNOON ON THURSDAY. FOG COULD BECOME A PROBLEM
AROUND DAYBREAK IF SIGNIFICANT RAIN HAPPENS LATE TONIGHT.
OTHERWISE...THE VSBY WAS KEPT ABOVE 5 MILES. THE FRONT SHOULD STAY
WEST OF THE TERMINAL THROUGH EARLY AFTERNOON AND WILL SERVE AS A
TRIGGER FOR NEW DEVELOPMENT BY LATE MORNING THURSDAY...THUS ANOTHER
PROB30 GROUP TOWARD THE END OF THE PERIOD. AS A RESULT...WIND
DIRECTION SHOULD REMAIN S TO SW.
ELSEWHERE...VFR FOR THE TIME BEING. CONVECTIVE CLOUD BASES SHOULD
REMAIN IN THE 035 TO 050 RANGE...MAINLY FEW TO SCT...AND THEN SHOULD
DROP INTO THE MVFR RANGE THIS EVENING AS CONVECTION BECOMES MORE
NUMEROUS. THE FRONT WILL PROBABLY MAKE IT INTO THE MTNS THURSDAY
MORNING SO THE WIND AT KAVL WAS SHIFTED TO NW. ANOTHER ROUND OF
SHOWERS AND STORMS IS POSSIBLE OVER NC THURSDAY LATE IN THE PERIOD.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 86% HIGH 100% HIGH 86% HIGH 90%
KGSP HIGH 100% MED 79% HIGH 87% HIGH 97%
KAVL HIGH 93% MED 77% HIGH 81% HIGH 97%
KHKY HIGH 93% MED 73% LOW 54% HIGH 80%
KGMU HIGH 100% MED 79% HIGH 83% HIGH 94%
KAND HIGH 100% HIGH 80% HIGH 82% HIGH 95%
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...JAT/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...PM
000
FXUS62 KGSP 221418
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1018 AM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF MID MORNING...A FEW SHOWERS AND THUNDERSTORMS ALREADY
DEVELOPING ALONG A LINEAR FEATURE STRETCHING N TO S ACROSS NE
GEORGIA. HAVE TWEAKED THE POP TO ACCOUNT FOR THIS EARLY
DEVELOPMENT...AND LACK OF DEVELOPMENT ACROSS THE PIEDMONT. RAISED
THE PRECIP CHANCES A BIT OVER THE WEST FOR LATE IN THE DAY WITH THE
EXPECTATION THAT A LINE OR BAND OF STORMS WILL DEVELOP OVER THE TN
VALLEY AND MAKE IT INTO THE FCST AREA. TEMPS LOOK OKAY.
PREVIOUS DISCUSSION...
AT 300 AM EST WEDNESDAY...AN UPPER TROUGH AXIS WILL SLOWLY CROSS THE
MS RIVER VALLEY TODAY AND TONIGHT. A SHORTWAVE ROUNDING THIS UPPER
TROUGH WILL REACH THE SOUTHERN APPALACHIANS THIS EVENING...CROSSING
OUR AREA OVERNIGHT. A WEAKENING COLD FRONT WILL APPROACH OUR AREA
FROM THE WEST TODAY...PRECEDED BY A BAND OF GULF MOISTURE...WHILE
ATLANTIC MOISTURE MOVES NORTH INTO THE PIEDMONT. THESE MOISTURE BAND
CONVERGE OVER OUR AREA TONIGHT. THE FRONT AND MOISTURE ALONG IT
REACH THE INTERSTATE 77 CORRIDOR BY THURSDAY MORNING. ALTHOUGH
INSTABILITY WILL PEAK DURING THE DAYLIGHT HOURS...WINDS SHEAR WILL
INCREASE THIS EVENING...OPENING A WIDER WINDOW FOR SEVERE WEATHER
POTENTIAL. THE MOISTENING AIR MASS WILL SUPPORT HEAVIER RAINFALL
WITH TIME. STEERING FLOW WILL INITIALLY MOVE CELLS INTO THE BLUE
RIDGE ESCARPMENT...BUT BY THE TIME THE BEST MOISTURE ARRIVES...CELL
MOVEMENT SHOULD BE MORE PARALLEL TO THE HIGHER TERRAIN. THIS WILL
LIMIT PRECIPITATION ACCUMULATION...AND NO LARGE SCALE HYDROLOGICAL
PROBLEMS ARE FORESEEN AT THIS TIME. TEMPERATURES WILL RUN A CATEGORY
OR TWO ABOVE NORMAL IN WARM ADVECTION.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM WEDNESDAY...SHORT WAVES MOVING THRU AN UPPER TROF PUSH
THE TROF AXIS TOWARD THU THEN INTO THE AREA THU NITE. AT THE SFC...
A PRE-FRONTAL TROF STARTS THE DAY OVER THE AREA WITH A COLD FRONT TO
OUR WEST. THIS FRONT JUMPS INTO THE TROF BY THE END OF THE DAY AND
MOVES EAST OF THE AREA THU NITE. THIS SETS UP TWO AREAS OF FORCING.
ONE OVER THE ERN CWFA ALONG THE TROF AND OVER THE MTNS AHEAD OF THE
FRONT. NE GA AND MUCH OF THE UPSTATE WILL BE BETWEEN THESE 2 AREAS.
THEREFORE...HAVE PUT THE HIGHEST POP OVER THE AREAS WITH BEST
FORCING...BUT DID KEEP LOW CHC POP OVER NE GA AND THE UPSTATE AS
THERE WILL BE WEAK INSTABILITY IN PLACE. BEST INSTABILITY AND SHEAR
WILL BE EAST OF THE AREA...SO DO NOT EXPECT ANY SIGNIFICANT COVERAGE
OF SVR STORMS. PRECIP CHC DIMINISHES OUTSIDE OF THE MTNS DURING THE
EVENING AS THE FRONT MOVES EAST. HOWEVER...SCT SHRA WILL LINGER OVER
THE NC MTNS IN THE DEVELOPING NW FLOW AND CONTINUED LOW LEVEL
MOISTURE. HIGHS THU AROUND 5 DEGREES ABOVE NORMAL WITH LOWS A COUPLE
OF DEGREES ABOVE NORMAL THU NITE.
THE UPPER TROF AXIS MOVES EAST OF THE AREA FRI WITH NWLY FLOW
REMAINING IN PLACE FRI NITE...WHILE SFC HIGH PRESSURE SLOWLY BUILDS
TOWARD THE AREA. ANY LINGERING NW FLOW SHRA END BY AFTERNOON. THE
BIGGER STORIES WILL BE THE WINDS AND COLD AIR MASS MOVING IN. EXPECT
WINDY CONDITIONS TO DEVELOP AS MIXING TAPS SIGNIFICANT LOW LEVEL
WINDS. THAT SAID...IT LOOKS LIKE WINDS AND GUSTS WILL REMAIN BELOW
WIND ADV LEVELS. HIGHS FRI WILL BE 5 TO 10 DEGREES BELOW NORMAL
WHILE LOWS FRI NITE END UP 10 TO 15 DEGREES BELOW NORMAL. RIGHT NOW
IT LOOKS LIKE WINDS WILL REMAIN TOO STRONG FOR ANY SIGNIFICANT FROST
FORMATION OVER THE NC MTNS. HOWEVER...WILL HAVE TO KEEP AN EYE ON
THIS AS TEMPS APPROACH FROSTY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 355 AM WEDNESDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
THRU THE MEDIUM RANGE. HOWEVER...THERE ARE SOME DETAIL DIFFERENCES.
NWLY UPPER FLOW REMAINS OVER THE AREA SAT AND SUN AS THE CWFA WILL
BE BETWEEN A TROF TO OUR EAST AND A RIDGE TO OUR WEST. THE FLOW
BECOMES ZONAL FOR MONDAY WITH WEAK RIDGING TUE. ALL THIS TIME...
SERIES OF SHORT WAVES MOVE THRU THE FLOW AND ACROSS THE AREA. AT THE
SFC...HIGH PRESSURE RIDGES IN FROM THE NW...BUT IS SPLIT BY A WEAK
BACK DOOR COLD FRONT. THIS FRONT REMAINS OVER OR NEAR THE AREA MON
AND TUE. PRECIP ACTIVATES ALONG THE FRONT FROM TIME TO TIME AS THE
WAVES MOVE OVER. HOWEVER...THE ECMWF IS MUCH MORE WIDESPREAD WITH
PRECIP THAN THE GFS. FOR NOW...HAVE FOLLOWED NATIONAL GUIDANCE AND
KEEP PRECIP LIMITED TO SLIGHT CHC XCPT ACROSS THE NRN MTNS FROM MON
NITE ON. HIGHS AROUND 5 DEGREES BELOW NORMAL SAT AND SUN...NEAR
NORMAL MON...THEN ABOUT 5 DEGREES ABOVE NORMAL TUE. LOWS 5 TO 10
DEGREES BELOW NORMAL SAT NITE...NEAR NORMAL SUN NITE...THEN A LITTLE
ABOVE NORMAL MON NITE.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...IFR CIGS HAS BROKEN UP...BUT A TEMPO FOR IFR CIG WILL BE
CARRIED IN THE TAF EARLY THIS MORNING. MVFR VSBY HAS BEEN FAIRLY
STABLE FOR SEVERAL HOURS...AND WILL BE MAINTAINED FOR ANOTHER HOUR.
BY MID MORNING LOW VFR CLOUDS AND UNRESTRICTED VSBY ARE EXPECTED.
MODEL SOUNDINGS SUPPORT AFTERNOON AND EARLY EVENING CONVECTION WITH
MOISTURE MOVING IN FROM THE SOUTH. SOUTHERLY WINDS WILL APPROACH 10
KNOTS THIS AFTERNOON...WITH GUSTS. A BLEND OF MODEL GUIDANCE DOES
NOT SUPPORT RESTRICTIONS EARLY THURSDAY.
ELSEWHERE...RESTRICTIONS WILL BE CARRIED FOR THE FIRST HOUR AT KGSP
AND KHKY PER OBSERVATION...AND AT KAVL WHERE TOW VERY LOW CLOUDS
LAYERS ARE PRESENT. KGMU AND KAND APPEAR TO HAVE LESS OF A CHANCE OF
RESTRICTIONS. LOW VFR CLOUDS WILL PREVAIL MOST OF TODAY...WITH
CONVECTION DEVELOPING BY THIS AFTERNOON AS A WEAKENING COLD FRONT
APPROACHES. ALTHOUGH CONVECTION WILL TAPER OFF TONIGHT...IT MAY
CONTINUE AT A DIMINISHED RATE AS THE FRONT GETS CLOSER...ESPECIALLY
IN THE MOUNTAINS. THE TAFS WILL FOCUS ON THE MOST LIKELY TIMING OF
CONVECTION. SSW WINDS WILL APPROACH 10 KNOTS TODAY...WITH GUSTS. A
BLEND OF MODEL GUIDANCE SUPPORTS MVFR FOG AT KAVL EARLY THURSDAY
MORNING...WITH LOW VFR AT ALL OTHER SITES BUT KAND.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 97% HIGH 100% HIGH 95% HIGH 96%
KGSP HIGH 97% HIGH 100% HIGH 90% MED 69%
KAVL HIGH 98% HIGH 98% HIGH 82% MED 64%
KHKY HIGH 94% HIGH 100% HIGH 86% LOW 56%
KGMU HIGH 96% HIGH 100% HIGH 93% MED 69%
KAND HIGH 96% HIGH 100% HIGH 93% MED 78%
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...JAT/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 221041
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
641 AM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 300 AM EST WEDNESDAY...AN UPPER TROUGH AXIS WILL SLOWLY CROSS THE
MS RIVER VALLEY TODAY AND TONIGHT. A SHORTWAVE ROUNDING THIS UPPER
TROUGH WILL REACH THE SOUTHERN APPALACHIANS THIS EVENING...CROSSING
OUR AREA OVERNIGHT. A WEAKENING COLD FRONT WILL APPROACH OUR AREA
FROM THE WEST TODAY...PRECEDED BY A BAND OF GULF MOISTURE...WHILE
ATLANTIC MOISTURE MOVES NORTH INTO THE PIEDMONT. THESE MOISTURE BAND
CONVERGE OVER OUR AREA TONIGHT. THE FRONT AND MOISTURE ALONG IT
REACH THE INTERSTATE 77 CORRIDOR BY THURSDAY MORNING. ALTHOUGH
INSTABILITY WILL PEAK DURING THE DAYLIGHT HOURS...WINDS SHEAR WILL
INCREASE THIS EVENING...OPENING A WIDER WINDOW FOR SEVERE WEATHER
POTENTIAL. THE MOISTENING AIR MASS WILL SUPPORT HEAVIER RAINFALL
WITH TIME. STEERING FLOW WILL INITIALLY MOVE CELLS INTO THE BLUE
RIDGE ESCARPMENT...BUT BY THE TIME THE BEST MOISTURE ARRIVES...CELL
MOVEMENT SHOULD BE MORE PARALLEL TO THE HIGHER TERRAIN. THIS WILL
LIMIT PRECIPITATION ACCUMULATION...AND NO LARGE SCALE HYDROLOGICAL
PROBLEMS ARE FORESEEN AT THIS TIME. TEMPERATURES WILL RUN A CATEGORY
OR TWO ABOVE NORMAL IN WARM ADVECTION.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM WEDNESDAY...SHORT WAVES MOVING THRU AN UPPER TROF PUSH
THE TROF AXIS TOWARD THU THEN INTO THE AREA THU NITE. AT THE SFC...
A PRE-FRONTAL TROF STARTS THE DAY OVER THE AREA WITH A COLD FRONT TO
OUR WEST. THIS FRONT JUMPS INTO THE TROF BY THE END OF THE DAY AND
MOVES EAST OF THE AREA THU NITE. THIS SETS UP TWO AREAS OF FORCING.
ONE OVER THE ERN CWFA ALONG THE TROF AND OVER THE MTNS AHEAD OF THE
FRONT. NE GA AND MUCH OF THE UPSTATE WILL BE BETWEEN THESE 2 AREAS.
THEREFORE...HAVE PUT THE HIGHEST POP OVER THE AREAS WITH BEST
FORCING...BUT DID KEEP LOW CHC POP OVER NE GA AND THE UPSTATE AS
THERE WILL BE WEAK INSTABILITY IN PLACE. BEST INSTABILITY AND SHEAR
WILL BE EAST OF THE AREA...SO DO NOT EXPECT ANY SIGNIFICANT COVERAGE
OF SVR STORMS. PRECIP CHC DIMINISHES OUTSIDE OF THE MTNS DURING THE
EVENING AS THE FRONT MOVES EAST. HOWEVER...SCT SHRA WILL LINGER OVER
THE NC MTNS IN THE DEVELOPING NW FLOW AND CONTINUED LOW LEVEL
MOISTURE. HIGHS THU AROUND 5 DEGREES ABOVE NORMAL WITH LOWS A COUPLE
OF DEGREES ABOVE NORMAL THU NITE.
THE UPPER TROF AXIS MOVES EAST OF THE AREA FRI WITH NWLY FLOW
REMAINING IN PLACE FRI NITE...WHILE SFC HIGH PRESSURE SLOWLY BUILDS
TOWARD THE AREA. ANY LINGERING NW FLOW SHRA END BY AFTERNOON. THE
BIGGER STORIES WILL BE THE WINDS AND COLD AIR MASS MOVING IN. EXPECT
WINDY CONDITIONS TO DEVELOP AS MIXING TAPS SIGNIFICANT LOW LEVEL
WINDS. THAT SAID...IT LOOKS LIKE WINDS AND GUSTS WILL REMAIN BELOW
WIND ADV LEVELS. HIGHS FRI WILL BE 5 TO 10 DEGREES BELOW NORMAL
WHILE LOWS FRI NITE END UP 10 TO 15 DEGREES BELOW NORMAL. RIGHT NOW
IT LOOKS LIKE WINDS WILL REMAIN TOO STRONG FOR ANY SIGNIFICANT FROST
FORMATION OVER THE NC MTNS. HOWEVER...WILL HAVE TO KEEP AN EYE ON
THIS AS TEMPS APPROACH FROSTY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 355 AM WEDNESDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
THRU THE MEDIUM RANGE. HOWEVER...THERE ARE SOME DETAIL DIFFERENCES.
NWLY UPPER FLOW REMAINS OVER THE AREA SAT AND SUN AS THE CWFA WILL
BE BETWEEN A TROF TO OUR EAST AND A RIDGE TO OUR WEST. THE FLOW
BECOMES ZONAL FOR MONDAY WITH WEAK RIDGING TUE. ALL THIS TIME...
SERIES OF SHORT WAVES MOVE THRU THE FLOW AND ACROSS THE AREA. AT THE
SFC...HIGH PRESSURE RIDGES IN FROM THE NW...BUT IS SPLIT BY A WEAK
BACK DOOR COLD FRONT. THIS FRONT REMAINS OVER OR NEAR THE AREA MON
AND TUE. PRECIP ACTIVATES ALONG THE FRONT FROM TIME TO TIME AS THE
WAVES MOVE OVER. HOWEVER...THE ECMWF IS MUCH MORE WIDESPREAD WITH
PRECIP THAN THE GFS. FOR NOW...HAVE FOLLOWED NATIONAL GUIDANCE AND
KEEP PRECIP LIMITED TO SLIGHT CHC XCPT ACROSS THE NRN MTNS FROM MON
NITE ON. HIGHS AROUND 5 DEGREES BELOW NORMAL SAT AND SUN...NEAR
NORMAL MON...THEN ABOUT 5 DEGREES ABOVE NORMAL TUE. LOWS 5 TO 10
DEGREES BELOW NORMAL SAT NITE...NEAR NORMAL SUN NITE...THEN A LITTLE
ABOVE NORMAL MON NITE.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...IFR CIGS EXTEND FROM THE FIELD NORTH ALONG INTERSTATE
77...WHILE SOME LIFR CIGS WERE NOTED TO THE SOUTH. MVFR VSBY HAS
BEEN FAIRLY STABLE FOR SEVERAL HOURS. THE FORECAST WILL MAINTAIN
CONTINUITY WITH THE CURRENT OBSERVATIONS UNTIL MID MORNING...WHEN
GUIDANCE SUPPORTS LOW VFR CLOUDS. MODEL SOUNDINGS SUPPORT AFTERNOON
AND EARLY EVENING CONVECTION WITH MOISTURE MOVING IN FROM THE SOUTH.
SOUTHERLY WINDS WILL APPROACH 10 KNOTS THIS AFTERNOON. A BLEND OF
MODEL GUIDANCE DOES NOT SUPPORT RESTRICTIONS EARLY THURSDAY.
ELSEWHERE...OTHER THAN AN MVFR CIG AT KAVL...RESTRICTIONS ARE
LOOKING LESS LIKELY EARLY THIS MORNING. LOW VFR CLOUDS WILL PREVAIL
MOST OF TODAY...WITH CONVECTION DEVELOPING BY THIS AFTERNOON AS A
WEAKENING COLD FRONT APPROACHES. ALTHOUGH CONVECTION WILL TAPER OFF
TONIGHT...IT MAY CONTINUE AT A DIMINISHED RATE AS THE FRONT GETS
CLOSER...ESPECIALLY IN THE MOUNTAINS. THE TAFS WILL FOCUS ON THE
MOST LIKELY TIMING OF CONVECTION. SSW WINDS WILL APPROACH 10 KNOTS
TODAY. A BLEND OF MODEL GUIDANCE SUPPORTS MVFR FOG AT KAVL EARLY
THURSDAY MORNING...WITH LOW VFR AT ALL OTHER SITES BUT KAND.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
10-16Z 16-22Z 22-04Z 04-10Z
KCLT HIGH 81% HIGH 100% HIGH 100% HIGH 97%
KGSP HIGH 92% HIGH 100% HIGH 98% HIGH 91%
KAVL MED 76% HIGH 98% HIGH 93% HIGH 82%
KHKY MED 74% HIGH 98% HIGH 98% HIGH 82%
KGMU HIGH 84% HIGH 100% HIGH 98% HIGH 91%
KAND MED 74% HIGH 100% HIGH 98% HIGH 90%
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...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 220758
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
358 AM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 300 AM EST WEDNESDAY...AN UPPER TROUGH AXIS WILL SLOWLY CROSS THE
MS RIVER VALLEY TODAY AND TONIGHT. A SHORTWAVE ROUNDING THIS UPPER
TROUGH WILL REACH THE SOUTHERN APPALACHIANS THIS EVENING...CROSSING
OUR AREA OVERNIGHT. A WEAKENING COLD FRONT WILL APPROACH OUR AREA
FROM THE WEST TODAY...PRECEDED BY A BAND OF GULF MOISTURE...WHILE
ATLANTIC MOISTURE MOVES NORTH INTO THE PIEDMONT. THESE MOISTURE BAND
CONVERGE OVER OUR AREA TONIGHT. THE FRONT AND MOISTURE ALONG IT
REACH THE INTERSTATE 77 CORRIDOR BY THURSDAY MORNING. ALTHOUGH
INSTABILITY WILL PEAK DURING THE DAYLIGHT HOURS...WINDS SHEAR WILL
INCREASE THIS EVENING...OPENING A WIDER WINDOW FOR SEVERE WEATHER
POTENTIAL. THE MOISTENING AIR MASS WILL SUPPORT HEAVIER RAINFALL
WITH TIME. STEERING FLOW WILL INITIALLY MOVE CELLS INTO THE BLUE
RIDGE ESCARPMENT...BUT BY THE TIME THE BEST MOISTURE ARRIVES...CELL
MOVEMENT SHOULD BE MORE PARALLEL TO THE HIGHER TERRAIN. THIS WILL
LIMIT PRECIPITATION ACCUMULATION...AND NO LARGE SCALE HYDROLOGICAL
PROBLEMS ARE FORESEEN AT THIS TIME. TEMPERATURES WILL RUN A CATEGORY
OR TWO ABOVE NORMAL IN WARM ADVECTION.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM WEDNESDAY...SHORT WAVES MOVING THRU AN UPPER TROF PUSH
THE TROF AXIS TOWARD THU THEN INTO THE AREA THU NITE. AT THE SFC...
A PRE-FRONTAL TROF STARTS THE DAY OVER THE AREA WITH A COLD FRONT TO
OUR WEST. THIS FRONT JUMPS INTO THE TROF BY THE END OF THE DAY AND
MOVES EAST OF THE AREA THU NITE. THIS SETS UP TWO AREAS OF FORCING.
ONE OVER THE ERN CWFA ALONG THE TROF AND OVER THE MTNS AHEAD OF THE
FRONT. NE GA AND MUCH OF THE UPSTATE WILL BE BETWEEN THESE 2 AREAS.
THEREFORE...HAVE PUT THE HIGHEST POP OVER THE AREAS WITH BEST
FORCING...BUT DID KEEP LOW CHC POP OVER NE GA AND THE UPSTATE AS
THERE WILL BE WEAK INSTABILITY IN PLACE. BEST INSTABILITY AND SHEAR
WILL BE EAST OF THE AREA...SO DO NOT EXPECT ANY SIGNIFICANT COVERAGE
OF SVR STORMS. PRECIP CHC DIMINISHES OUTSIDE OF THE MTNS DURING THE
EVENING AS THE FRONT MOVES EAST. HOWEVER...SCT SHRA WILL LINGER OVER
THE NC MTNS IN THE DEVELOPING NW FLOW AND CONTINUED LOW LEVEL
MOISTURE. HIGHS THU AROUND 5 DEGREES ABOVE NORMAL WITH LOWS A COUPLE
OF DEGREES ABOVE NORMAL THU NITE.
THE UPPER TROF AXIS MOVES EAST OF THE AREA FRI WITH NWLY FLOW
REMAINING IN PLACE FRI NITE...WHILE SFC HIGH PRESSURE SLOWLY BUILDS
TOWARD THE AREA. ANY LINGERING NW FLOW SHRA END BY AFTERNOON. THE
BIGGER STORIES WILL BE THE WINDS AND COLD AIR MASS MOVING IN. EXPECT
WINDY CONDITIONS TO DEVELOP AS MIXING TAPS SIGNIFICANT LOW LEVEL
WINDS. THAT SAID...IT LOOKS LIKE WINDS AND GUSTS WILL REMAIN BELOW
WIND ADV LEVELS. HIGHS FRI WILL BE 5 TO 10 DEGREES BELOW NORMAL
WHILE LOWS FRI NITE END UP 10 TO 15 DEGREES BELOW NORMAL. RIGHT NOW
IT LOOKS LIKE WINDS WILL REMAIN TOO STRONG FOR ANY SIGNIFICANT FROST
FORMATION OVER THE NC MTNS. HOWEVER...WILL HAVE TO KEEP AN EYE ON
THIS AS TEMPS APPROACH FROSTY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 355 AM WEDNESDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
THRU THE MEDIUM RANGE. HOWEVER...THERE ARE SOME DETAIL DIFFERENCES.
NWLY UPPER FLOW REMAINS OVER THE AREA SAT AND SUN AS THE CWFA WILL
BE BETWEEN A TROF TO OUR EAST AND A RIDGE TO OUR WEST. THE FLOW
BECOMES ZONAL FOR MONDAY WITH WEAK RIDGING TUE. ALL THIS TIME...
SERIES OF SHORT WAVES MOVE THRU THE FLOW AND ACROSS THE AREA. AT THE
SFC...HIGH PRESSURE RIDGES IN FROM THE NW...BUT IS SPLIT BY A WEAK
BACK DOOR COLD FRONT. THIS FRONT REMAINS OVER OR NEAR THE AREA MON
AND TUE. PRECIP ACTIVATES ALONG THE FRONT FROM TIME TO TIME AS THE
WAVES MOVE OVER. HOWEVER...THE ECMWF IS MUCH MORE WIDESPREAD WITH
PRECIP THAN THE GFS. FOR NOW...HAVE FOLLOWED NATIONAL GUIDANCE AND
KEEP PRECIP LIMITED TO SLIGHT CHC XCPT ACROSS THE NRN MTNS FROM MON
NITE ON. HIGHS AROUND 5 DEGREES BELOW NORMAL SAT AND SUN...NEAR
NORMAL MON...THEN ABOUT 5 DEGREES ABOVE NORMAL TUE. LOWS 5 TO 10
DEGREES BELOW NORMAL SAT NITE...NEAR NORMAL SUN NITE...THEN A LITTLE
ABOVE NORMAL MON NITE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...LIFR CIG AND MVFR VSBY WILL LKELY BE AROUDN FOR MUCH OF
THE EARLY MORNING. OTHERWISE A LOW VFR CIG IS EXPECTED FROM MID
MORING UNTIL THIS EVENING...WHEN GUIDANCE WOULD SUGGEST A MID TO
UPPER LEVEL CIG. ONCE AGAIN...MODEL SOUNDINGS SUPPORT ROBUST
CONVECTION... AND MODEL DATA SHOWS MOISTURE MOVING IN FROM THE
SOUTH. A MENTION OF THUNDERSTORMS WILL BE MADE IN THE TAF LATE THIS
AFTERNOON AND EARLY THIS EVENING. SOUTHERLY WINDS WILL APPROACH 10
KNOTS THIS AFTERNOON.
ELSEWHERE...GUIDANCE SUPPORTS MVFR CIGS AT FOOTHILL SITES TOWARD
DAWN...AND MVFR VSBY AT ALL SITES BUT KGSP AND KGMU...WHERE LOW VFR
VSBY IS SUPPORTED. IF KAVL CAN FOG UP TO IFR...A LOW CIG WOULD
PROBABLY FORM. VFR RETURNS BY MID MORNING. ANOTHER AFTERNOON OF
ROBUST CONVECTION IS EXPECTED AS AN UPPER TROUGH APPROACHES...WITH
THE BEST COVERAGE IN THE MOUNTAINS. CONVECTION MAY DIMINISH SOME IN
THE EVENING WITH THE LOSS OF HEATING...BUT NOT ENTIRELY...AS COLD
FRONT ARRIVES FROM THE WEST. SSW WINDS WILL APPROACH 10 KNOTS THIS
AFTERNOON.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 82% HIGH 97% HIGH 100% HIGH 100%
KGSP HIGH 86% HIGH 98% HIGH 100% HIGH 100%
KAVL HIGH 83% HIGH 100% HIGH 95% HIGH 82%
KHKY HIGH 86% HIGH 93% HIGH 100% HIGH 94%
KGMU MED 79% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 88% HIGH 97% HIGH 96% 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...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 220757
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
357 AM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
0515 UTC UPDATE...POPS HAVE BEEN RAISED IN THE NORTHERN NC MOUNTAINS
AND THE NE GA MOUNTAINS BASED ON RADAR TRENDS...EVEN THROUGH
CONVECTION IN THOSE AREAS IS DIMINISHING. WINDS WERE UPDATE TO
INCLUDE THE 00Z NAM. SKY COVER WAS INCREASED PER SATELLITE IMAGERY.
AS OF 1030 PM...CONVECTION CONTINUES TO GRADUALLY WANE WITH LOSS OF
DAYTIME HEATING. A FEW LINGERING SUB-SEVERE STORMS WILL CONTINUE TO
AFFECT MAINLY THE NRN MTNS AND NRN NC FOOTHILLS...BUT EXPECTING ALL
ACTIVITY TO DIE OFF BY AROUND 06Z. EXPECTING SIMILAR CONDITIONS TO
LAST NIGHT WITH PATCHY FOG DEVELOPING IN THE MTN VLYS AND LWR
PIEDMONT WHERE THE RAIN WAS HEAVIEST. MAY BE LOCALLY DENSE. TEMPS
LOOK ON TRACK.
AS OF 800 PM...A LITTLE BIT OF SHORTWAVE ENERGY CROSSING THE WRN
THIRD OF THE CWFA IS WORKING TO ENHANCE CONVECTION.
FORTUNATELY...SHEAR IS STILL WEAK AND THE LAST OF THE UN-OVERNTURNED
AIR MASS IS CURRENTLY BEING WORKED OVER. SO STILL EXPECT THINGS TO
WIND DOWN OVER THE NEXT 2-4 HOURS. THE REST OF THE CWFA SHUD REMAIN
TRANQUIL. POPS WERE ADJUSTED ACCORDINGLY...WITH OTHER CHANGES BEING
FOR 00Z AVIATION GRIDS.
AS OF 530 PM...CONVECTION HAS BEEN FAVORING THE WESTERN SITE OF THE
CWFA IN THE LAST HOUR OR SO...AS DECENT WWD PROPAGATING OUTFLOW
BNDRYS ARE WORKING INTO 3500 J/KG CAPE AIR MASS. THE PULSE
CONVECTION HAS BEEN FAIRLY ROBUST...WITH LARGE HAIL AND DAMAGING
WIND THREATS. HAVE UPDATED THE POPS...BLENDING IN THE 18Z NAM AND
LATEST HRRR...WHICH AGREE ON CONVECTION WORKING OVER THE UPPER
SAVANNAH VALLEY AND SW NC MTNS DURING THE EARLY EVENING HOURS.
MEANWHILE...CONVECTION IS TRYING TO ORGANIZE OVER ERN TN WHERE THE
BETTER UPPER FORCING AND DEEP LAYER SHEAR EXISTS. I/M EXPECTING MOST
OF THIS TO STRUGGLE TO REACH THE SRN APPALACHIANS...DUE TO THE LACK
OF SHEAR AND FORCING OVER OUR AREA.
AT 230 PM EST TUESDAY...STILL SEEING AN EVOLVING CONVECTIVE
SITUATION ACROSS THE CWFA AS WEAK FORCING IS MAINTAINED WITHIN A
VERY BROAD H5 TROF. STILL EXPECT PULSE SEVERE LATER THIS AFTERNOON
MAINLY ACROSS THE ERN UPSTATE ALIGNED WITH A LINE OF VORT ENERGY AND
ACROSS NC MTNS WHERE RATHER STEEP LAPSE RATES ARE MOVING IN FROM THE
WEST. THESE STORMS WILL BE MAINLY DIURNALLY DRIVEN...BUT SOME -SHRA
WILL BE MAINTAINED ACROSS THE NC MTNS IN UPSLOPE FLOW THROUGH THE
MID MORNING. DEBRIS CLOUDS WILL PERSIST OVERNIGHT...BUT ENOUGH
CLEARING SHOULD BE HAD TO ENABLE MORNING FG...AND PATCHY/AREAS OF
DENSE FG THROUGH 13Z OR SO. NOT MUCH CHANGE IS IN STORE WITH THE
SYNOPTIC PATTERN WED. THE WRN UPPER TROF IMPINGES UPON THE AREA AND
THE WRN ZONES WILL HAVE A BETTER CHANCE FOR AFTERNOON PRECIP/CONV
THAN THE ERN ZONES AND HAVE MAINTAINED HIGH END CHANCES ACROSS THE
MTNS. A GOOD HEATING DAY IN SW/LY FLOW WITH MAXES A COUPLE DEGREES
ABOVE NORMAL WILL SET THE STAGE FOR ANOTHER HIGH CAPE ENVIRONMENT
AND PULSE SEVERE STORMS POSSIBLE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM WEDNESDAY...SHORT WAVES MOVING THRU AN UPPER TROF PUSH
THE TROF AXIS TOWARD THU THEN INTO THE AREA THU NITE. AT THE SFC...
A PRE-FRONTAL TROF STARTS THE DAY OVER THE AREA WITH A COLD FRONT TO
OUR WEST. THIS FRONT JUMPS INTO THE TROF BY THE END OF THE DAY AND
MOVES EAST OF THE AREA THU NITE. THIS SETS UP TWO AREAS OF FORCING.
ONE OVER THE ERN CWFA ALONG THE TROF AND OVER THE MTNS AHEAD OF THE
FRONT. NE GA AND MUCH OF THE UPSTATE WILL BE BETWEEN THESE 2 AREAS.
THEREFORE...HAVE PUT THE HIGHEST POP OVER THE AREAS WITH BEST
FORCING...BUT DID KEEP LOW CHC POP OVER NE GA AND THE UPSTATE AS
THERE WILL BE WEAK INSTABILITY IN PLACE. BEST INSTABILITY AND SHEAR
WILL BE EAST OF THE AREA...SO DO NOT EXPECT ANY SIGNIFICANT COVERAGE
OF SVR STORMS. PRECIP CHC DIMINISHES OUTSIDE OF THE MTNS DURING THE
EVENING AS THE FRONT MOVES EAST. HOWEVER...SCT SHRA WILL LINGER OVER
THE NC MTNS IN THE DEVELOPING NW FLOW AND CONTINUED LOW LEVEL
MOISTURE. HIGHS THU AROUND 5 DEGREES ABOVE NORMAL WITH LOWS A COUPLE
OF DEGREES ABOVE NORMAL THU NITE.
THE UPPER TROF AXIS MOVES EAST OF THE AREA FRI WITH NWLY FLOW
REMAINING IN PLACE FRI NITE...WHILE SFC HIGH PRESSURE SLOWLY BUILDS
TOWARD THE AREA. ANY LINGERING NW FLOW SHRA END BY AFTERNOON. THE
BIGGER STORIES WILL BE THE WINDS AND COLD AIR MASS MOVING IN. EXPECT
WINDY CONDITIONS TO DEVELOP AS MIXING TAPS SIGNIFICANT LOW LEVEL
WINDS. THAT SAID...IT LOOKS LIKE WINDS AND GUSTS WILL REMAIN BELOW
WIND ADV LEVELS. HIGHS FRI WILL BE 5 TO 10 DEGREES BELOW NORMAL
WHILE LOWS FRI NITE END UP 10 TO 15 DEGREES BELOW NORMAL. RIGHT NOW
IT LOOKS LIKE WINDS WILL REMAIN TOO STRONG FOR ANY SIGNIFICANT FROST
FORMATION OVER THE NC MTNS. HOWEVER...WILL HAVE TO KEEP AN EYE ON
THIS AS TEMPS APPROACH FROSTY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 355 AM WEDNESDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
THRU THE MEDIUM RANGE. HOWEVER...THERE ARE SOME DETAIL DIFFERENCES.
NWLY UPPER FLOW REMAINS OVER THE AREA SAT AND SUN AS THE CWFA WILL
BE BETWEEN A TROF TO OUR EAST AND A RIDGE TO OUR WEST. THE FLOW
BECOMES ZONAL FOR MONDAY WITH WEAK RIDGING TUE. ALL THIS TIME...
SERIES OF SHORT WAVES MOVE THRU THE FLOW AND ACROSS THE AREA. AT THE
SFC...HIGH PRESSURE RIDGES IN FROM THE NW...BUT IS SPLIT BY A WEAK
BACK DOOR COLD FRONT. THIS FRONT REMAINS OVER OR NEAR THE AREA MON
AND TUE. PRECIP ACTIVATES ALONG THE FRONT FROM TIME TO TIME AS THE
WAVES MOVE OVER. HOWEVER...THE ECMWF IS MUCH MORE WIDESPREAD WITH
PRECIP THAN THE GFS. FOR NOW...HAVE FOLLOWED NATIONAL GUIDANCE AND
KEEP PRECIP LIMITED TO SLIGHT CHC XCPT ACROSS THE NRN MTNS FROM MON
NITE ON. HIGHS AROUND 5 DEGREES BELOW NORMAL SAT AND SUN...NEAR
NORMAL MON...THEN ABOUT 5 DEGREES ABOVE NORMAL TUE. LOWS 5 TO 10
DEGREES BELOW NORMAL SAT NITE...NEAR NORMAL SUN NITE...THEN A LITTLE
ABOVE NORMAL MON NITE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...LIFR CIG AND MVFR VSBY WILL LKELY BE AROUDN FOR MUCH OF
THE EARLY MORNING. OTHERWISE A LOW VFR CIG IS EXPECTED FROM MID
MORING UNTIL THIS EVENING...WHEN GUIDANCE WOULD SUGGEST A MID TO
UPPER LEVEL CIG. ONCE AGAIN...MODEL SOUNDINGS SUPPORT ROBUST
CONVECTION... AND MODEL DATA SHOWS MOISTURE MOVING IN FROM THE
SOUTH. A MENTION OF THUNDERSTORMS WILL BE MADE IN THE TAF LATE THIS
AFTERNOON AND EARLY THIS EVENING. SOUTHERLY WINDS WILL APPROACH 10
KNOTS THIS AFTERNOON.
ELSEWHERE...GUIDANCE SUPPORTS MVFR CIGS AT FOOTHILL SITES TOWARD
DAWN...AND MVFR VSBY AT ALL SITES BUT KGSP AND KGMU...WHERE LOW VFR
VSBY IS SUPPORTED. IF KAVL CAN FOG UP TO IFR...A LOW CIG WOULD
PROBABLY FORM. VFR RETURNS BY MID MORNING. ANOTHER AFTERNOON OF
ROBUST CONVECTION IS EXPECTED AS AN UPPER TROUGH APPROACHES...WITH
THE BEST COVERAGE IN THE MOUNTAINS. CONVECTION MAY DIMINISH SOME IN
THE EVENING WITH THE LOSS OF HEATING...BUT NOT ENTIRELY...AS COLD
FRONT ARRIVES FROM THE WEST. SSW WINDS WILL APPROACH 10 KNOTS THIS
AFTERNOON.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 82% HIGH 97% HIGH 100% HIGH 100%
KGSP HIGH 86% HIGH 98% HIGH 100% HIGH 100%
KAVL HIGH 83% HIGH 100% HIGH 95% HIGH 82%
KHKY HIGH 86% HIGH 93% HIGH 100% HIGH 94%
KGMU MED 79% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 88% HIGH 97% HIGH 96% 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...JAT
SHORT TERM...CDG/RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KGSP 220515
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
115 AM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH MIDWEEK. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
0515 UTC UPDATE...POPS HAVE BEEN RAISED IN THE NORTHERN NC MOUNTAINS
AND THE NE GA MOUNTAINS BASED ON RADAR TRENDS...EVEN THROUGH
CONVECTION IN THOSE AREAS IS DIMINISHING. WINDS WERE UPDATE TO
INCLUDE THE 00Z NAM. SKY COVER WAS INCREASED PER SATELLITE IMAGERY.
AS OF 1030 PM...CONVECTION CONTINUES TO GRADUALLY WANE WITH LOSS OF
DAYTIME HEATING. A FEW LINGERING SUB-SEVERE STORMS WILL CONTINUE TO
AFFECT MAINLY THE NRN MTNS AND NRN NC FOOTHILLS...BUT EXPECTING ALL
ACTIVITY TO DIE OFF BY AROUND 06Z. EXPECTING SIMILAR CONDITIONS TO
LAST NIGHT WITH PATCHY FOG DEVELOPING IN THE MTN VLYS AND LWR
PIEDMONT WHERE THE RAIN WAS HEAVIEST. MAY BE LOCALLY DENSE. TEMPS
LOOK ON TRACK.
AS OF 800 PM...A LITTLE BIT OF SHORTWAVE ENERGY CROSSING THE WRN
THIRD OF THE CWFA IS WORKING TO ENHANCE CONVECTION.
FORTUNATELY...SHEAR IS STILL WEAK AND THE LAST OF THE UN-OVERNTURNED
AIR MASS IS CURRENTLY BEING WORKED OVER. SO STILL EXPECT THINGS TO
WIND DOWN OVER THE NEXT 2-4 HOURS. THE REST OF THE CWFA SHUD REMAIN
TRANQUIL. POPS WERE ADJUSTED ACCORDINGLY...WITH OTHER CHANGES BEING
FOR 00Z AVIATION GRIDS.
AS OF 530 PM...CONVECTION HAS BEEN FAVORING THE WESTERN SITE OF THE
CWFA IN THE LAST HOUR OR SO...AS DECENT WWD PROPAGATING OUTFLOW
BNDRYS ARE WORKING INTO 3500 J/KG CAPE AIR MASS. THE PULSE
CONVECTION HAS BEEN FAIRLY ROBUST...WITH LARGE HAIL AND DAMAGING
WIND THREATS. HAVE UPDATED THE POPS...BLENDING IN THE 18Z NAM AND
LATEST HRRR...WHICH AGREE ON CONVECTION WORKING OVER THE UPPER
SAVANNAH VALLEY AND SW NC MTNS DURING THE EARLY EVENING HOURS.
MEANWHILE...CONVECTION IS TRYING TO ORGANIZE OVER ERN TN WHERE THE
BETTER UPPER FORCING AND DEEP LAYER SHEAR EXISTS. I/M EXPECTING MOST
OF THIS TO STRUGGLE TO REACH THE SRN APPALACHIANS...DUE TO THE LACK
OF SHEAR AND FORCING OVER OUR AREA.
AT 230 PM EST TUESDAY...STILL SEEING AN EVOLVING CONVECTIVE
SITUATION ACROSS THE CWFA AS WEAK FORCING IS MAINTAINED WITHIN A
VERY BROAD H5 TROF. STILL EXPECT PULSE SEVERE LATER THIS AFTERNOON
MAINLY ACROSS THE ERN UPSTATE ALIGNED WITH A LINE OF VORT ENERGY AND
ACROSS NC MTNS WHERE RATHER STEEP LAPSE RATES ARE MOVING IN FROM THE
WEST. THESE STORMS WILL BE MAINLY DIURNALLY DRIVEN...BUT SOME -SHRA
WILL BE MAINTAINED ACROSS THE NC MTNS IN UPSLOPE FLOW THROUGH THE
MID MORNING. DEBRIS CLOUDS WILL PERSIST OVERNIGHT...BUT ENOUGH
CLEARING SHOULD BE HAD TO ENABLE MORNING FG...AND PATCHY/AREAS OF
DENSE FG THROUGH 13Z OR SO. NOT MUCH CHANGE IS IN STORE WITH THE
SYNOPTIC PATTERN WED. THE WRN UPPER TROF IMPINGES UPON THE AREA AND
THE WRN ZONES WILL HAVE A BETTER CHANCE FOR AFTERNOON PRECIP/CONV
THAN THE ERN ZONES AND HAVE MAINTAINED HIGH END CHANCES ACROSS THE
MTNS. A GOOD HEATING DAY IN SW/LY FLOW WITH MAXES A COUPLE DEGREES
ABOVE NORMAL WILL SET THE STAGE FOR ANOTHER HIGH CAPE ENVIRONMENT
AND PULSE SEVERE STORMS POSSIBLE.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
AS OF 210 PM TUESDAY...MODEL GUIDANCE REMAINS IN FAIRLY GOOD
AGREEMENT WITH REGARDS TO THE WEATHER ACROSS NORTHEAST GEORGIA AND
THE CAROLINAS FOR THE REMAINDER OF THE WORK WEEK. DEEP UPPER LEVEL
TROF AND AN ASSOCIATED SURFACE COLD FRONT WILL SLOWLY MIGRATE
EASTWARD OVER THE NEXT 24 HOURS. SURFACE RIDGING TO THE SOUTHEAST
WILL ALLOW FOR SOUTHERLY FLOW...THUS SETTING UP A MODEST WARM SECTOR
ACROSS THE REGION ON THURSDAY LEADING TO ABOVE NORMAL TEMPERATURES.
EXPECTING COLD FRONT TO MOVE INTO FAR WESTERN PORTIONS OF THE CWA BY
AROUND 12Z THURSDAY MORNING. PRECIPITATION CHANCES WILL INCREASE
NEAR AND ALONG THIS BOUNDARY AS IT MOVES ACROSS THE NORTH CAROLINA
MOUNTAINS...AND THEN SPREADS EASTWARD ACROSS THE PIEDMONTS. HIGHEST
POPS WILL BE ACROSS THE NORTH CAROLINA FOOTHILLS/PIEDMONT DUE TO
CLOSER PROXIMITY TO BOTH UPPER AND SFC LOWS. EXPECTING ANY ACTIVITY
ACROSS THE ABOVE MENTIONED REGIONS DURING THE MID TO LATE MORNING
HOURS ON THURSDAY TO REMAIN SUBSEVERE AS LOW LEVEL INVERSION REMAINS
IN PLACE. LATER IN THE AFTERNOON AS SURFACE TEMPS INCREASE INTO THE
80S NEAR AND ALONG THE I85 CORRIDOR...AND SHEAR PROFILES IMPROVE
SOMEWHAT ALONG THE PASSING FRONTAL BOUNDARY...A SVR STORM OR TWO
CANNOT BE RULED OUT. CONDITIONS WILL IMPROVE ACROSS THE REGION LATE
ON THURSDAY AS DIURNAL HEATING IS LOST...AND DRIER AIR BEGINS TO
ADVECT IN BEHIND THE FRONT.
SLIGHT CHANCE POPS REMAIN IN THE FCST ACROSS THE HIGHER TERRAIN
DURING THE EARLY MORNING HOURS ON FRIDAY MORNING. BY DAYBREAK...ALL
PRECIPITATION SHOULD HAVE DISSIPATED AND SKIES WILL BEGIN TO CLEAR
AS HIGH PRESSURE BUILDS. UPPER LEVEL RIDGING ACROSS THE MIDWEST
WILL ADVECT TO THE EAST DURING THE DAY ON FRIDAY ALLOWING HEIGHTS TO
BUILD OVER NORTHEAST GEORGIA AND THE CAROLINAS...LEADING TO PLEASANT
WEATHER CONDITIONS FOR THE REMAINDER OF FRIDAY EVENING.
TEMPERATURES ON FRIDAY WILL BE ON AVERAGE ABOUT TEN DEGREES COOLER
THAN PREVIOUS DAYS AS NORTHWEST FLOW USHERS IN A COOLER/DRIER
AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 220 PM TUESDAY...THE SHORTWAVE TROUGH MOVES OFF THE EAST COAST
FRIDAY NIGHT AND DRIER COOLER AIR FILTERS IN FROM THE NORTHWEST.
DRIEST AIR VARIES PER MODEL FROM FRIDAY NIGHT THROUGH THE DAY
SATURDAY. AS THE UPPER RIDGE SLOWLY BUILDS FROM THE WEST AND WARM
FRONT CHANNELS SHOWERS CLOSER TO THE NC MTNS TO START THE NEW
WEEK...POPS WILL INCREASE AT LEAST INTO THE SLIGHT RANGE. BASED ON
THE BLEND OF THE MODELS...LOOKS LIKE THE BEST TIME FOR RAIN WILL BE
GOING INTO MID WEEK. SEEMS BEST ORGANIZED BANDS OF CONVECTION WOULD
BE LATE TUESDAY. CONSIDERED GOING TO LOW CHANCE POPS AT THAT
TIME...BUT THAT IS A WEEK AWAY AND MUCH COULD CHANGE. CAPES ON THE
GFS FOR TUES PM ARE 1100 TO 1400 AND WINDS GOING UP FROM SURFACE NOT
TOO BAD FOR THAT TIME. TEMPERATURES...HIGHS NEAR NORMAL OR SLIGHTLY
BELOW AND LOWS COOLER THAN NORMAL EARLY IN WEEKEND AND GOING ABOVE
INTO NEW WEEK.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...A BLEND OF THE ADJMAV AND ADJMET SUPPORTS AN MVFR CIG
BRIEFLY AROUND DAWN...OTHERWISE A LOW VFR CIG WILL PERSIST UNTIL
THIS EVENING...WHEN GUIDANCE WOULD SUGGEST A MID LEVEL CIG. GUIDANCE
ONLY SUPPORTS LOW VFR VSBY AT DAYBREAK...WHICH SEEMS REASONABLE
BASED ON THE ABSENCE OF PRECIPITATION AT THE FIELD. VFR SHOULD
RETURN BY MID MORNING. ONCE AGAIN...MODEL SOUNDINGS SUPPORT ROBUST
CONVECTION... AND MODEL DATA SHOWS MOISTURE MOVING IN FROM THE
SOUTH. A MENTION OF THUNDERSTORMS WILL BE MADE IN THE TAF LATE THIS
AFTERNOON AND EARLY THIS EVENING. SOUTHERLY WINDS WILL APPROACH 10
KNOTS THIS AFTERNOON.
ELSEWHERE...GUIDANCE SUPPORTS MVFR CIGS AT FOOTHILL SITES TOWARD
DAWN...AND MVFR VSBY AT ALL SITES BUT KGSP AND KGMU...WHERE LOW VFR
VSBY IS SUPPORTED. IF KAVL CAN FOG UP TO IFR...A LOW CIG WOULD
PROBABLY FORM. VFR RETURNS BY MID MORNING. ANOTHER AFTERNOON OF
ROBUST CONVECTION IS EXPECTED AS AN UPPER TROUGH APPROACHES...WITH
THE BEST COVERAGE IN THE MOUNTAINS. CONVECTION MAY DIMINISH SOME IN
THE EVENING WITH THE LOSS OF HEATING...BUT NOT ENTIRELY...AS COLD
FRONT ARRIVES FROM THE WEST. SSW WINDS WILL APPROACH 10 KNOTS THIS
AFTERNOON.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 94% HIGH 94% HIGH 100% HIGH 100%
KGSP HIGH 94% HIGH 88% HIGH 100% HIGH 100%
KAVL HIGH 97% HIGH 97% HIGH 100% HIGH 91%
KHKY HIGH 91% HIGH 81% HIGH 100% HIGH 100%
KGMU HIGH 82% HIGH 95% HIGH 100% HIGH 100%
KAND HIGH 94% HIGH 86% 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...LEV
NEAR TERM...ARK/JAT/SBK
SHORT TERM...CDG
LONG TERM...DEO
AVIATION...ARK/JAT
000
FXUS62 KGSP 220231
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1031 PM EDT TUE MAY 21 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH MIDWEEK. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1030 PM...CONVECTION CONTINUES TO GRADUALLY WANE WITH LOSS OF
DAYTIME HEATING. A FEW LINGERING SUB-SEVERE STORMS WILL CONTINUE TO
AFFECT MAINLY THE NRN MTNS AND NRN NC FOOTHILLS...BUT EXPECTING ALL
ACTIVITY TO DIE OFF BY AROUND 06Z. EXPECTING SIMILAR CONDITIONS TO
LAST NIGHT WITH PATCHY FOG DEVELOPING IN THE MTN VLYS AND LWR
PIEDMONT WHERE THE RAIN WAS HEAVIEST. MAY BE LOCALLY DENSE. TEMPS
LOOK ON TRACK.
AS OF 800 PM...A LITTLE BIT OF SHORTWAVE ENERGY CROSSING THE WRN
THIRD OF THE CWFA IS WORKING TO ENHANCE CONVECTION.
FORTUNATELY...SHEAR IS STILL WEAK AND THE LAST OF THE UN-OVERNTURNED
AIR MASS IS CURRENTLY BEING WORKED OVER. SO STILL EXPECT THINGS TO
WIND DOWN OVER THE NEXT 2-4 HOURS. THE REST OF THE CWFA SHUD REMAIN
TRANQUIL. POPS WERE ADJUSTED ACCORDINGLY...WITH OTHER CHANGES BEING
FOR 00Z AVIATION GRIDS.
AS OF 530 PM...CONVECTION HAS BEEN FAVORING THE WESTERN SITE OF THE
CWFA IN THE LAST HOUR OR SO...AS DECENT WWD PROPAGATING OUTFLOW
BNDRYS ARE WORKING INTO 3500 J/KG CAPE AIR MASS. THE PULSE
CONVECTION HAS BEEN FAIRLY ROBUST...WITH LARGE HAIL AND DAMAGING
WIND THREATS. HAVE UPDATED THE POPS...BLENDING IN THE 18Z NAM AND
LATEST HRRR...WHICH AGREE ON CONVECTION WORKING OVER THE UPPER
SAVANNAH VALLEY AND SW NC MTNS DURING THE EARLY EVENING HOURS.
MEANWHILE...CONVECTION IS TRYING TO ORGANIZE OVER ERN TN WHERE THE
BETTER UPPER FORCING AND DEEP LAYER SHEAR EXISTS. I/M EXPECTING MOST
OF THIS TO STRUGGLE TO REACH THE SRN APPALACHIANS...DUE TO THE LACK
OF SHEAR AND FORCING OVER OUR AREA.
AT 230 PM EST TUESDAY...STILL SEEING AN EVOLVING CONVECTIVE
SITUATION ACROSS THE CWFA AS WEAK FORCING IS MAINTAINED WITHIN A
VERY BROAD H5 TROF. STILL EXPECT PULSE SEVERE LATER THIS AFTERNOON
MAINLY ACROSS THE ERN UPSTATE ALIGNED WITH A LINE OF VORT ENERGY AND
ACROSS NC MTNS WHERE RATHER STEEP LAPSE RATES ARE MOVING IN FROM THE
WEST. THESE STORMS WILL BE MAINLY DIURNALLY DRIVEN...BUT SOME -SHRA
WILL BE MAINTAINED ACROSS THE NC MTNS IN UPSLOPE FLOW THROUGH THE
MID MORNING. DEBRIS CLOUDS WILL PERSIST OVERNIGHT...BUT ENOUGH
CLEARING SHOULD BE HAD TO ENABLE MORNING FG...AND PATCHY/AREAS OF
DENSE FG THROUGH 13Z OR SO. NOT MUCH CHANGE IS IN STORE WITH THE
SYNOPTIC PATTERN WED. THE WRN UPPER TROF IMPINGES UPON THE AREA AND
THE WRN ZONES WILL HAVE A BETTER CHANCE FOR AFTERNOON PRECIP/CONV
THAN THE ERN ZONES AND HAVE MAINTAINED HIGH END CHANCES ACROSS THE
MTNS. A GOOD HEATING DAY IN SW/LY FLOW WITH MAXES A COUPLE DEGREES
ABOVE NORMAL WILL SET THE STAGE FOR ANOTHER HIGH CAPE ENVIRONMENT
AND PULSE SEVERE STORMS POSSIBLE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 210 PM TUESDAY...MODEL GUIDANCE REMAINS IN FAIRLY GOOD
AGREEMENT WITH REGARDS TO THE WEATHER ACROSS NORTHEAST GEORGIA AND
THE CAROLINAS FOR THE REMAINDER OF THE WORK WEEK. DEEP UPPER LEVEL
TROF AND AN ASSOCIATED SURFACE COLD FRONT WILL SLOWLY MIGRATE
EASTWARD OVER THE NEXT 24 HOURS. SURFACE RIDGING TO THE SOUTHEAST
WILL ALLOW FOR SOUTHERLY FLOW...THUS SETTING UP A MODEST WARM SECTOR
ACROSS THE REGION ON THURSDAY LEADING TO ABOVE NORMAL TEMPERATURES.
EXPECTING COLD FRONT TO MOVE INTO FAR WESTERN PORTIONS OF THE CWA BY
AROUND 12Z THURSDAY MORNING. PRECIPITATION CHANCES WILL INCREASE
NEAR AND ALONG THIS BOUNDARY AS IT MOVES ACROSS THE NORTH CAROLINA
MOUNTAINS...AND THEN SPREADS EASTWARD ACROSS THE PIEDMONTS. HIGHEST
POPS WILL BE ACROSS THE NORTH CAROLINA FOOTHILLS/PIEDMONT DUE TO
CLOSER PROXIMITY TO BOTH UPPER AND SFC LOWS. EXPECTING ANY ACTIVITY
ACROSS THE ABOVE MENTIONED REGIONS DURING THE MID TO LATE MORNING
HOURS ON THURSDAY TO REMAIN SUBSEVERE AS LOW LEVEL INVERSION REMAINS
IN PLACE. LATER IN THE AFTERNOON AS SURFACE TEMPS INCREASE INTO THE
80S NEAR AND ALONG THE I85 CORRIDOR...AND SHEAR PROFILES IMPROVE
SOMEWHAT ALONG THE PASSING FRONTAL BOUNDARY...A SVR STORM OR TWO
CANNOT BE RULED OUT. CONDITIONS WILL IMPROVE ACROSS THE REGION LATE
ON THURSDAY AS DIURNAL HEATING IS LOST...AND DRIER AIR BEGINS TO
ADVECT IN BEHIND THE FRONT.
SLIGHT CHANCE POPS REMAIN IN THE FCST ACROSS THE HIGHER TERRAIN
DURING THE EARLY MORNING HOURS ON FRIDAY MORNING. BY DAYBREAK...ALL
PRECIPITATION SHOULD HAVE DISSIPATED AND SKIES WILL BEGIN TO CLEAR
AS HIGH PRESSURE BUILDS. UPPER LEVEL RIDGING ACROSS THE MIDWEST
WILL ADVECT TO THE EAST DURING THE DAY ON FRIDAY ALLOWING HEIGHTS TO
BUILD OVER NORTHEAST GEORGIA AND THE CAROLINAS...LEADING TO PLEASANT
WEATHER CONDITIONS FOR THE REMAINDER OF FRIDAY EVENING.
TEMPERATURES ON FRIDAY WILL BE ON AVERAGE ABOUT TEN DEGREES COOLER
THAN PREVIOUS DAYS AS NORTHWEST FLOW USHERS IN A COOLER/DRIER
AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 220 PM TUESDAY...THE SHORTWAVE TROUGH MOVES OFF THE EAST COAST
FRIDAY NIGHT AND DRIER COOLER AIR FILTERS IN FROM THE NORTHWEST.
DRIEST AIR VARIES PER MODEL FROM FRIDAY NIGHT THROUGH THE DAY
SATURDAY. AS THE UPPER RIDGE SLOWLY BUILDS FROM THE WEST AND WARM
FRONT CHANNELS SHOWERS CLOSER TO THE NC MTNS TO START THE NEW
WEEK...POPS WILL INCREASE AT LEAST INTO THE SLIGHT RANGE. BASED ON
THE BLEND OF THE MODELS...LOOKS LIKE THE BEST TIME FOR RAIN WILL BE
GOING INTO MID WEEK. SEEMS BEST ORGANIZED BANDS OF CONVECTION WOULD
BE LATE TUESDAY. CONSIDERED GOING TO LOW CHANCE POPS AT THAT
TIME...BUT THAT IS A WEEK AWAY AND MUCH COULD CHANGE. CAPES ON THE
GFS FOR TUES PM ARE 1100 TO 1400 AND WINDS GOING UP FROM SURFACE NOT
TOO BAD FOR THAT TIME. TEMPERATURES...HIGHS NEAR NORMAL OR SLIGHTLY
BELOW AND LOWS COOLER THAN NORMAL EARLY IN WEEKEND AND GOING ABOVE
INTO NEW WEEK.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR WITH A LIGHT S/SE WIND UNDER CONVECTIVE DEBRIS CLOUDS
OVERNIGHT. GUIDANCE IS SHOWING STRATUS AND FOG DEVELOPING AGAIN ACRS
THE REGION DURING THE PRE-DAWN HOURS. WILL GO WITH AN IFR CIG RIGHT
AROUND DAYBREAK...SIMILAR TO LAST MORNING. THE CLOUDS SHUD
QUICKLY LIFT AND SCATTER AFTER SUNRISE. SCATTERED CONVECTION
EXPECTED AGAIN WEDNESDAY AFTN. WILL GO WITH A PROB30.
ELSEWHERE...VFR EXPECTED THIS EVENING...AS CONVECTION GRADUALLY
WANES TO THE WEST. EXPECTING SIMILAR CONDITIONS OVERNIGHT TO WHAT
OCCURRED THE PREVIOUS NIGHT. FOG AND STRATUS EXPECTED TO DEVELOP
FIRST INT HE MTNS VLYS...THEN ACRS THE PIEDMONT CLOSER TO DAYBREAK.
FOG AND STRATUS SHUD DISSIPATE AFTER SUNRISE WEDNESDAY. SCATTERED TO
NUMEROUS SHRA/TSRA EXPECTED WEDNESDAY AFTN. WILL GO WITH PROB30 FOR
TS AT ALL SITES FROM 18Z TO 00Z.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 91% HIGH 98% HIGH 100%
KGSP HIGH 100% HIGH 86% HIGH 96% HIGH 100%
KAVL HIGH 97% HIGH 90% HIGH 100% HIGH 100%
KHKY HIGH 88% MED 74% HIGH 96% HIGH 100%
KGMU HIGH 100% HIGH 86% HIGH 96% HIGH 100%
KAND HIGH 100% HIGH 81% HIGH 93% 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...LEV
NEAR TERM...ARK/SBK
SHORT TERM...CDG
LONG TERM...DEO
AVIATION...ARK
000
FXUS62 KGSP 220002
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
802 PM EDT TUE MAY 21 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH MIDWEEK. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 800 PM...A LITTLE BIT OF SHORTWAVE ENERGY CROSSING THE WRN
THIRD OF THE CWFA IS WORKING TO ENHANCE CONVECTION.
FORTUNATELY...SHEAR IS STILL WEAK AND THE LAST OF THE UN-OVERNTURNED
AIR MASS IS CURRENTLY BEING WORKED OVER. SO STILL EXPECT THINGS TO
WIND DOWN OVER THE NEXT 2-4 HOURS. THE REST OF THE CWFA SHUD REMAIN
TRANQUIL. POPS WERE ADJUSTED ACCORDINGLY...WITH OTHER CHANGES BEING
FOR 00Z AVIATION GRIDS.
AS OF 530 PM...CONVECTION HAS BEEN FAVORING THE WESTERN SITE OF THE
CWFA IN THE LAST HOUR OR SO...AS DECENT WWD PROPAGATING OUTFLOW
BNDRYS ARE WORKING INTO 3500 J/KG CAPE AIR MASS. THE PULSE
CONVECTION HAS BEEN FAIRLY ROBUST...WITH LARGE HAIL AND DAMAGING
WIND THREATS. HAVE UPDATED THE POPS...BLENDING IN THE 18Z NAM AND
LATEST HRRR...WHICH AGREE ON CONVECTION WORKING OVER THE UPPER
SAVANNAH VALLEY AND SW NC MTNS DURING THE EARLY EVENING HOURS.
MEANWHILE...CONVECTION IS TRYING TO ORGANIZE OVER ERN TN WHERE THE
BETTER UPPER FORCING AND DEEP LAYER SHEAR EXISTS. I/M EXPECTING MOST
OF THIS TO STRUGGLE TO REACH THE SRN APPALACHIANS...DUE TO THE LACK
OF SHEAR AND FORCING OVER OUR AREA.
AT 230 PM EST TUESDAY...STILL SEEING AN EVOLVING CONVECTIVE
SITUATION ACROSS THE CWFA AS WEAK FORCING IS MAINTAINED WITHIN A
VERY BROAD H5 TROF. STILL EXPECT PULSE SEVERE LATER THIS AFTERNOON
MAINLY ACROSS THE ERN UPSTATE ALIGNED WITH A LINE OF VORT ENERGY AND
ACROSS NC MTNS WHERE RATHER STEEP LAPSE RATES ARE MOVING IN FROM THE
WEST. THESE STORMS WILL BE MAINLY DIURNALLY DRIVEN...BUT SOME -SHRA
WILL BE MAINTAINED ACROSS THE NC MTNS IN UPSLOPE FLOW THROUGH THE
MID MORNING. DEBRIS CLOUDS WILL PERSIST OVERNIGHT...BUT ENOUGH
CLEARING SHOULD BE HAD TO ENABLE MORNING FG...AND PATCHY/AREAS OF
DENSE FG THROUGH 13Z OR SO. NOT MUCH CHANGE IS IN STORE WITH THE
SYNOPTIC PATTERN WED. THE WRN UPPER TROF IMPINGES UPON THE AREA AND
THE WRN ZONES WILL HAVE A BETTER CHANCE FOR AFTERNOON PRECIP/CONV
THAN THE ERN ZONES AND HAVE MAINTAINED HIGH END CHANCES ACROSS THE
MTNS. A GOOD HEATING DAY IN SW/LY FLOW WITH MAXES A COUPLE DEGREES
ABOVE NORMAL WILL SET THE STAGE FOR ANOTHER HIGH CAPE ENVIRONMENT
AND PULSE SEVERE STORMS POSSIBLE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 210 PM TUESDAY...MODEL GUIDANCE REMAINS IN FAIRLY GOOD
AGREEMENT WITH REGARDS TO THE WEATHER ACROSS NORTHEAST GEORGIA AND
THE CAROLINAS FOR THE REMAINDER OF THE WORK WEEK. DEEP UPPER LEVEL
TROF AND AN ASSOCIATED SURFACE COLD FRONT WILL SLOWLY MIGRATE
EASTWARD OVER THE NEXT 24 HOURS. SURFACE RIDGING TO THE SOUTHEAST
WILL ALLOW FOR SOUTHERLY FLOW...THUS SETTING UP A MODEST WARM SECTOR
ACROSS THE REGION ON THURSDAY LEADING TO ABOVE NORMAL TEMPERATURES.
EXPECTING COLD FRONT TO MOVE INTO FAR WESTERN PORTIONS OF THE CWA BY
AROUND 12Z THURSDAY MORNING. PRECIPITATION CHANCES WILL INCREASE
NEAR AND ALONG THIS BOUNDARY AS IT MOVES ACROSS THE NORTH CAROLINA
MOUNTAINS...AND THEN SPREADS EASTWARD ACROSS THE PIEDMONTS. HIGHEST
POPS WILL BE ACROSS THE NORTH CAROLINA FOOTHILLS/PIEDMONT DUE TO
CLOSER PROXIMITY TO BOTH UPPER AND SFC LOWS. EXPECTING ANY ACTIVITY
ACROSS THE ABOVE MENTIONED REGIONS DURING THE MID TO LATE MORNING
HOURS ON THURSDAY TO REMAIN SUBSEVERE AS LOW LEVEL INVERSION REMAINS
IN PLACE. LATER IN THE AFTERNOON AS SURFACE TEMPS INCREASE INTO THE
80S NEAR AND ALONG THE I85 CORRIDOR...AND SHEAR PROFILES IMPROVE
SOMEWHAT ALONG THE PASSING FRONTAL BOUNDARY...A SVR STORM OR TWO
CANNOT BE RULED OUT. CONDITIONS WILL IMPROVE ACROSS THE REGION LATE
ON THURSDAY AS DIURNAL HEATING IS LOST...AND DRIER AIR BEGINS TO
ADVECT IN BEHIND THE FRONT.
SLIGHT CHANCE POPS REMAIN IN THE FCST ACROSS THE HIGHER TERRAIN
DURING THE EARLY MORNING HOURS ON FRIDAY MORNING. BY DAYBREAK...ALL
PRECIPITATION SHOULD HAVE DISSIPATED AND SKIES WILL BEGIN TO CLEAR
AS HIGH PRESSURE BUILDS. UPPER LEVEL RIDGING ACROSS THE MIDWEST
WILL ADVECT TO THE EAST DURING THE DAY ON FRIDAY ALLOWING HEIGHTS TO
BUILD OVER NORTHEAST GEORGIA AND THE CAROLINAS...LEADING TO PLEASANT
WEATHER CONDITIONS FOR THE REMAINDER OF FRIDAY EVENING.
TEMPERATURES ON FRIDAY WILL BE ON AVERAGE ABOUT TEN DEGREES COOLER
THAN PREVIOUS DAYS AS NORTHWEST FLOW USHERS IN A COOLER/DRIER
AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 220 PM TUESDAY...THE SHORTWAVE TROUGH MOVES OFF THE EAST COAST
FRIDAY NIGHT AND DRIER COOLER AIR FILTERS IN FROM THE NORTHWEST.
DRIEST AIR VARIES PER MODEL FROM FRIDAY NIGHT THROUGH THE DAY
SATURDAY. AS THE UPPER RIDGE SLOWLY BUILDS FROM THE WEST AND WARM
FRONT CHANNELS SHOWERS CLOSER TO THE NC MTNS TO START THE NEW
WEEK...POPS WILL INCREASE AT LEAST INTO THE SLIGHT RANGE. BASED ON
THE BLEND OF THE MODELS...LOOKS LIKE THE BEST TIME FOR RAIN WILL BE
GOING INTO MID WEEK. SEEMS BEST ORGANIZED BANDS OF CONVECTION WOULD
BE LATE TUESDAY. CONSIDERED GOING TO LOW CHANCE POPS AT THAT
TIME...BUT THAT IS A WEEK AWAY AND MUCH COULD CHANGE. CAPES ON THE
GFS FOR TUES PM ARE 1100 TO 1400 AND WINDS GOING UP FROM SURFACE NOT
TOO BAD FOR THAT TIME. TEMPERATURES...HIGHS NEAR NORMAL OR SLIGHTLY
BELOW AND LOWS COOLER THAN NORMAL EARLY IN WEEKEND AND GOING ABOVE
INTO NEW WEEK.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR WITH A LIGHT S/SE WIND UNDER CONVECTIVE DEBRIS CLOUDS
OVERNIGHT. GUIDANCE IS SHOWING STRATUS AND FOG DEVELOPING AGAIN ACRS
THE REGION DURING THE PRE-DAWN HOURS. WILL GO WITH AN IFR CIG RIGHT
AROUND DAYBREAK...SIMILAR TO LAST MORNING. THE CLOUDS SHUD
QUICKLY LIFT AND SCATTER AFTER SUNRISE. SCATTERED CONVECTION
EXPECTED AGAIN WEDNESDAY AFTN. WILL GO WITH A PROB30.
ELSEWHERE...VFR EXPECTED THIS EVENING...AS CONVECTION GRADUALLY
WANES TO THE WEST. EXPECTING SIMILAR CONDITIONS OVERNIGHT TO WHAT
OCCURRED THE PREVIOUS NIGHT. FOG AND STRATUS EXPECTED TO DEVELOP
FIRST INT HE MTNS VLYS...THEN ACRS THE PIEDMONT CLOSER TO DAYBREAK.
FOG AND STRATUS SHUD DISSIPATE AFTER SUNRISE WEDNESDAY. SCATTERED TO
NUMEROUS SHRA/TSRA EXPECTED WEDNESDAY AFTN. WILL GO WITH PROB30 FOR
TS AT ALL SITES FROM 18Z TO 00Z.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 100% HIGH 91% HIGH 90% HIGH 100%
KGSP HIGH 100% HIGH 91% HIGH 85% HIGH 100%
KAVL HIGH 100% HIGH 89% HIGH 94% HIGH 100%
KHKY HIGH 100% MED 62% HIGH 91% HIGH 100%
KGMU HIGH 100% HIGH 89% HIGH 87% HIGH 100%
KAND HIGH 100% HIGH 89% HIGH 86% 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...LEV
NEAR TERM...ARK/SBK
SHORT TERM...CDG
LONG TERM...DEO
AVIATION...ARK
000
FXUS62 KGSP 212145
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
545 PM EDT TUE MAY 21 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH MIDWEEK. SOUTHERLY FLOW WILL KEEP THE AREA WARM AND
GENERALLY UNSETTLED WITH STORM CHANCES EACH AFTERNOON. A COOLER AND
DRIER AIRMASS SETTLES IN FOR THE WEEKEND AFTER A COLD FRONT MOVES
THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 530 PM...CONVECTION HAS BEEN FAVORING THE WESTERN SITE OF THE
CWFA IN THE LAST HOUR OR SO...AS DECENT WWD PROPAGATING OUTFLOW
BNDRYS ARE WORKING INTO 3500 J/KG CAPE AIR MASS. THE PULSE
CONVECTION HAS BEEN FAIRLY ROBUST...WITH LARGE HAIL AND DAMAGING
WIND THREATS. HAVE UPDATED THE POPS...BLENDING IN THE 18Z NAM AND
LATEST HRRR...WHICH AGREE ON CONVECTION WORKING OVER THE UPPER
SAVANNAH VALLEY AND SW NC MTNS DURING THE EARLY EVENING HOURS.
MEANWHILE...CONVECTION IS TRYING TO ORGANIZE OVER ERN TN WHERE THE
BETTER UPPER FORCING AND DEEP LAYER SHEAR EXISTS. I/M EXPECTING MOST
OF THIS TO STRUGGLE TO REACH THE SRN APPALACHIANS...DUE TO THE LACK
OF SHEAR AND FORCING OVER OUR AREA.
AT 230 PM EST TUESDAY...STILL SEEING AN EVOLVING CONVECTIVE
SITUATION ACROSS THE CWFA AS WEAK FORCING IS MAINTAINED WITHIN A
VERY BROAD H5 TROF. STILL EXPECT PULSE SEVERE LATER THIS AFTERNOON
MAINLY ACROSS THE ERN UPSTATE ALIGNED WITH A LINE OF VORT ENERGY AND
ACROSS NC MTNS WHERE RATHER STEEP LAPSE RATES ARE MOVING IN FROM THE
WEST. THESE STORMS WILL BE MAINLY DIURNALLY DRIVEN...BUT SOME -SHRA
WILL BE MAINTAINED ACROSS THE NC MTNS IN UPSLOPE FLOW THROUGH THE
MID MORNING. DEBRIS CLOUDS WILL PERSIST OVERNIGHT...BUT ENOUGH
CLEARING SHOULD BE HAD TO ENABLE MORNING FG...AND PATCHY/AREAS OF
DENSE FG THROUGH 13Z OR SO. NOT MUCH CHANGE IS IN STORE WITH THE
SYNOPTIC PATTERN WED. THE WRN UPPER TROF IMPINGES UPON THE AREA AND
THE WRN ZONES WILL HAVE A BETTER CHANCE FOR AFTERNOON PRECIP/CONV
THAN THE ERN ZONES AND HAVE MAINTAINED HIGH END CHANCES ACROSS THE
MTNS. A GOOD HEATING DAY IN SW/LY FLOW WITH MAXES A COUPLE DEGREES
ABOVE NORMAL WILL SET THE STAGE FOR ANOTHER HIGH CAPE ENVIRONMENT
AND PULSE SEVERE STORMS POSSIBLE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 210 PM TUESDAY...MODEL GUIDANCE REMAINS IN FAIRLY GOOD
AGREEMENT WITH REGARDS TO THE WEATHER ACROSS NORTHEAST GEORGIA AND
THE CAROLINAS FOR THE REMAINDER OF THE WORK WEEK. DEEP UPPER LEVEL
TROF AND AN ASSOCIATED SURFACE COLD FRONT WILL SLOWLY MIGRATE
EASTWARD OVER THE NEXT 24 HOURS. SURFACE RIDGING TO THE SOUTHEAST
WILL ALLOW FOR SOUTHERLY FLOW...THUS SETTING UP A MODEST WARM SECTOR
ACROSS THE REGION ON THURSDAY LEADING TO ABOVE NORMAL TEMPERATURES.
EXPECTING COLD FRONT TO MOVE INTO FAR WESTERN PORTIONS OF THE CWA BY
AROUND 12Z THURSDAY MORNING. PRECIPITATION CHANCES WILL INCREASE
NEAR AND ALONG THIS BOUNDARY AS IT MOVES ACROSS THE NORTH CAROLINA
MOUNTAINS...AND THEN SPREADS EASTWARD ACROSS THE PIEDMONTS. HIGHEST
POPS WILL BE ACROSS THE NORTH CAROLINA FOOTHILLS/PIEDMONT DUE TO
CLOSER PROXIMITY TO BOTH UPPER AND SFC LOWS. EXPECTING ANY ACTIVITY
ACROSS THE ABOVE MENTIONED REGIONS DURING THE MID TO LATE MORNING
HOURS ON THURSDAY TO REMAIN SUBSEVERE AS LOW LEVEL INVERSION REMAINS
IN PLACE. LATER IN THE AFTERNOON AS SURFACE TEMPS INCREASE INTO THE
80S NEAR AND ALONG THE I85 CORRIDOR...AND SHEAR PROFILES IMPROVE
SOMEWHAT ALONG THE PASSING FRONTAL BOUNDARY...A SVR STORM OR TWO
CANNOT BE RULED OUT. CONDITIONS WILL IMPROVE ACROSS THE REGION LATE
ON THURSDAY AS DIURNAL HEATING IS LOST...AND DRIER AIR BEGINS TO
ADVECT IN BEHIND THE FRONT.
SLIGHT CHANCE POPS REMAIN IN THE FCST ACROSS THE HIGHER TERRAIN
DURING THE EARLY MORNING HOURS ON FRIDAY MORNING. BY DAYBREAK...ALL
PRECIPITATION SHOULD HAVE DISSIPATED AND SKIES WILL BEGIN TO CLEAR
AS HIGH PRESSURE BUILDS. UPPER LEVEL RIDGING ACROSS THE MIDWEST
WILL ADVECT TO THE EAST DURING THE DAY ON FRIDAY ALLOWING HEIGHTS TO
BUILD OVER NORTHEAST GEORGIA AND THE CAROLINAS...LEADING TO PLEASANT
WEATHER CONDITIONS FOR THE REMAINDER OF FRIDAY EVENING.
TEMPERATURES ON FRIDAY WILL BE ON AVERAGE ABOUT TEN DEGREES COOLER
THAN PREVIOUS DAYS AS NORTHWEST FLOW USHERS IN A COOLER/DRIER
AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 220 PM TUESDAY...THE SHORTWAVE TROUGH MOVES OFF THE EAST COAST
FRIDAY NIGHT AND DRIER COOLER AIR FILTERS IN FROM THE NORTHWEST.
DRIEST AIR VARIES PER MODEL FROM FRIDAY NIGHT THROUGH THE DAY
SATURDAY. AS THE UPPER RIDGE SLOWLY BUILDS FROM THE WEST AND WARM
FRONT CHANNELS SHOWERS CLOSER TO THE NC MTNS TO START THE NEW
WEEK...POPS WILL INCREASE AT LEAST INTO THE SLIGHT RANGE. BASED ON
THE BLEND OF THE MODELS...LOOKS LIKE THE BEST TIME FOR RAIN WILL BE
GOING INTO MID WEEK. SEEMS BEST ORGANIZED BANDS OF CONVECTION WOULD
BE LATE TUESDAY. CONSIDERED GOING TO LOW CHANCE POPS AT THAT
TIME...BUT THAT IS A WEEK AWAY AND MUCH COULD CHANGE. CAPES ON THE
GFS FOR TUES PM ARE 1100 TO 1400 AND WINDS GOING UP FROM SURFACE NOT
TOO BAD FOR THAT TIME. TEMPERATURES...HIGHS NEAR NORMAL OR SLIGHTLY
BELOW AND LOWS COOLER THAN NORMAL EARLY IN WEEKEND AND GOING ABOVE
INTO NEW WEEK.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
AT KCLT...EXPECT LOW VFR CIGS THIS AFTERNOON WITH PERIODIC PULSE
CONVECTION DEVELOPING WITHIN THE TAF ZONE BY 21Z AND PERSISTING
THROUGH 01Z. DEBRIS CLOUDS OVERNIGHT WILL LOWER...SIMILAR TO THIS
MORNING...AND SHUD HELP CREATE MVFR CIGS BY DAYBREAK. ALSO
ANTICIPATE MVFR VSBY AFT 07Z THROUGH 13Z.
ELSEWHERE...VFR CONDS...BUT RESTRICTIVE CONVECTION WILL BECOME MORE
WIDESPREAD THIS AFTERNOON...THUS ALL TAF SITES WERE GIVEN A TEMPO
TSRA THROUGH MID EVENING. A MOIST ATMOS WILL PERSIST OVERNIGHT WITH
DEBRIS CLOUDS LOWERING AND ANTICIPATE MVFR CIGS NON/MTNS AND IFR
CIGS/VSBY AT KAVL DEVELOPING A FEW HRS BEFORE DAYBREAK.
OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS
AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER
FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 100% HIGH 100% LOW 59% HIGH 100%
KGSP HIGH 100% HIGH 100% MED 73% HIGH 100%
KAVL HIGH 95% MED 66% MED 69% HIGH 93%
KHKY HIGH 100% HIGH 100% MED 78% HIGH 97%
KGMU HIGH 100% HIGH 100% MED 76% HIGH 100%
KAND HIGH 100% HIGH 100% MED 78% 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...LEV
NEAR TERM...ARK/SBK
SHORT TERM...CDG
LONG TERM...DEO
AVIATION...SBK
| 
