[top]
000
FXUS62 KCAE 230022
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
822 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA INTENSIFYING PAST COUPLE
OF HOURS IN AREA OF STRONG INSTABILITY. LIFT ENHANCED BY
APPROACHING SHORT WAVE TROUGH NOW MOVING INTO WESTERN GEORGIA.
CONVECTION MAY MOVE INTO WESTERN CSRA/PIEDMONT THIS EVENING. WILL
INCREASE POPS IN THAT AREA. DECREASED POPS ACROSS REST OF REGION
WITH LITTLE FORCING FOR CONVECTION THIS EVENING.
SKIES WILL BECOME MOSTLY CLOUDY TONIGHT WITH SOME LOW CLOUDS
EXPECTED. FRONT APPROACHING LATE CANT RULE OUT A SHOWERS LATE
TONIGHT...BUT SHOULD REMAIN ISOLATED. OVERNIGHT LOWS WILL
GENERALLY BE IN THE MID 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIR MASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE EAST MIDLANDS.
WILL RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST
ON THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE
THE COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING. CUT POPS AFTER 18Z FROM PREVIOUS FORECAST BASED
ON LATEST MODEL TRENDS.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
RADAR INDICATES CONVECTIVE ACTIVITY AT A MINIMUM ACROSS OUR FA. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC AND N/CENT GA. HIGH
RES MODELS INDICATE ACTIVITY DEVELOPING TO OUR WEST NEAR AN UPPER
IMPULSE AND SURFACE TROUGH...WEAKENING AS IT MOVES EAST AND
APPROACHES THE FA LATE TONIGHT. GUIDANCE INDICATING CIG RESTRICTIONS
LATE TONIGHT...IN A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW. FOR
NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL MONITOR LATEST
GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED. UPPER IMPULSE
AND SURFACE TROUGH WILL MOVE THROUGH THURSDAY...POSSIBLY LEADING
TO SCT SHRA/TSRA...BUT CHANCES TOO LOW...ALONG WITH SOME TIMING
QUESTIONS...TO INCLUDE MENTION IN THE TAF AT THIS TIME.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
[top]
000
FXUS62 KFFC 222353 AAA
AFDFFC
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
753 PM EDT WED MAY 22 2013
.UPDATE...
QUICK UPDATE TO GRIDS. APPEARS COVERAGE OF TSRA OVER ERN AL AND
WRN GA LOWER THAN MODEL FCSTS. WILL BACK OFF ON POPS. MLCAPE
PRETTY STOUT WITH VALUES 1500-2000 J/KG AND 0-6KM BULK SHEAR
AROUND 20-30KTS. APPARENTLY FORCING AND LOCALIZED LIFT IS LACKING.
WILL CONTINUE TO MONITOR.
SNELSON
&&
.PREV DISCUSSION... /ISSUED 350 PM EDT WED MAY 22 2013/
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AFTERNOON CONVECTION EXPECTED TO INCREASE IN COVERAGE AND PERSIST
INTO THE EVENING AND OVERNIGHT HOURS AS UPPER LEVEL TROUGH MOVES
THROUGH THE MISSISSIPPI VALLEY. CONVECTION EXPECTED TO BECOME MORE
ORGANIZED AS ASSOCIATED SHORT WAVE FOCUSES DEVELOPMENT. MODELS A
LITTLE INCONSISTENT WITH THE DEVELOPMENT AND/OR PROGRESSION OF THE
ORGANIZED PRECIPITATION...BUT WITH INCREASING
INSTABILITIES...DIURNAL HEATING...AND INCREASING SHEAR ACROSS THE
AREA...FEEL THERE IS ENOUGH TO SUPPORT GOOD CHANCE TO LIKELY
POPS...ESPECIALLY ACROSS NORTH GEORGIA. HAVE CONTINUED MENTION OF
POSSIBLE SEVERE STORMS...ACCOMPANIED WITH GUSTY WINDS AND SMALL
HAIL...IN THE GRIDS THROUGH 02Z TONIGHT ACROSS NORTH
GEORGIA...GENERALLY NORTH OF THE ATL METRO AREA. HAVE ALSO
QUICKLY TAPERED OFF EVENING AND OVERNIGHT POPS INTO THURSDAY
MORNING...WITH GENERALLY SLIGHT CHANCE POPS ACROSS THE AREA THROUGH
THE DAY THURSDAY AS SHORT WAVE PUSHES INTO THE CAROLINAS.
AS PREVIOUSLY MENTIONED...THE SEVERE THREAT IS PRIMARILY CONFINED TO
NORTH GEORGIA...THOUGH STRONG STORMS CAN BE EXPECTED ACROSS MUCH OF
THE CWA. THE PRIMARY CONCERNS IN SEVERE ACTIVITY WILL BE GUSTY WINDS
TO 60 MPH OR HIGHER...1 INCH HAIL OR HIGHER...FREQUENT LIGHTNING AND
PERIODS OF HEAVY RAINFALL. GUSTY WINDS AND SMALL HAIL ARE ALSO
POSSIBLE IN THE STRONGER STORMS.
PRESSURE GRADIENT TIGHTENS THURSDAY AFTERNOON AND INTO FRIDAY...WITH
WINDS 10 TO 15 MPH WITH GUSTS NEAR 20 MPH...ESPECIALLY ACROSS NORTHERN
AND EASTERN GEORGIA.
FOR THE TEMPERATURES..HAVE GENERALLY GONE WITH A GUIDANCE BLEND.
TEMPERATURES THURSDAY MORNING ARE EXPECTED TO BE IN THE 60S...AND
DEPENDING ON THE TIMING OF THE DIMINISHING CONVECTION AND CLOUDS OUT
OF THE AREA...THIS COULD IMPACT MORNING LOWS BY A FEW DEGREES.
TEMPERATURES WILL BE BACK IN THE LOW TO MID 80S THURSDAY AFTERNOON
BEFORE COOLING BY FRIDAY.
31
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO MAJOR CHANGES MADE TO THE EXTENDED PORTION OF THE FORECAST. A MUCH
DRIER AIRMASS MOVES OVER THE AREA FRIDAY WITH DRY NW FLOW ALOFT
AND SURFACE HIGH PRESSURE BUILDING OVER THE OH/TN VALLEYS DURING
THE DAY. GRADIENT WINDS WILL INCREASE GETTING CLOSE TO WIND
ADVISORY CRITERIA(20 MPH SUSTAINED) FOR SOME AREAS. DRY CONDITIONS
SHOULD CONTINUE THROUGH THE WEEKEND EVEN WITH SLIGHT DIFFERENCES
BETWEEN THE GFS AND ECMWF. THE NW FLOW ALOFT N OF THE AREA IS
EXPECTED TO BECOME MORE ACTIVE WITH INCREASED PRECIP CHANCES NORTH
OF THE STATE...BUT IT SHOULD STAY DRY ACROSS GA. LOOKS LIKE THE
BETTER MOISTURE FINALLY MOVES IN ACROSS THE AREA BY THE BEGINNING
OF NEXT WEEK SO WILL SLOWLY INCREASE CHANCES OF POPS MON THROUGH DAY
7. TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF NORMAL
THROUGH THE PERIOD EXCEPT SATURDAY ND SUNDAY MORNING LOWS ARE
RUNNING 10-15 DEGREES BELOW NORMAL.
01
&&
.AVIATION...
00Z UPDATE...
CONFIDENCE ON WIDESPREAD TSRA DROPPING OVER MUCH OF THE AREA. WILL
CONTINUE TEMPO TSRA BUT BASED ON TRENDS...MAY HAVE TO PULL THIS
OUT LATER THIS EVENING. ANY PRECIP SHOULD END OR BE EAST OF FCST
POINTS BY 06Z. WINDS WILL SHIFT TO WEST AFTER 07Z AND NW AFTER
SUNRISE. NOT MUCH CHANCE FOR RADIATIONAL FOG UNLESS PRECIP BECOMES
MORE WIDESPREAD. HAVE BACKED OFF ON FOG FOR MOST SITES. COULD SEE
SOME GUSTS TO 25KTS THURS AFTERNOON WITH GOOD VERTICAL MIXING.
//ATL CONFIDENCE...00Z UPDATE...
LOW CONFIDENCE ON LIKELIHOOD OF TSRA THIS EVENING.
LOW CONFIDENCE ON RADIATIONAL FOG THURS MORNING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 85 59 79 / 60 20 5 0
ATLANTA 66 83 59 76 / 70 10 5 0
BLAIRSVILLE 61 78 54 71 / 70 20 10 0
CARTERSVILLE 64 83 57 76 / 70 10 5 0
COLUMBUS 68 89 63 82 / 70 10 5 0
GAINESVILLE 64 82 57 75 / 70 10 5 0
MACON 66 89 60 83 / 60 20 5 0
ROME 64 84 57 77 / 50 10 5 0
PEACHTREE CITY 64 85 58 77 / 70 10 5 0
VIDALIA 68 89 65 88 / 40 20 5 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....BAKER
AVIATION...SNELSON
[top]
000
FXUS62 KCHS 222339
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
734 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
QUITE A CHANGE IN THE PATTERN SINCE YESTERDAY...WITH MUCH OF THE
AREA VOID OF ANY CONVECTION EARLIER TODAY. WE/RE FINISHED FOR THE
EVENING FOR ANY SHOWERS OR T-STORMS IN THE LOCAL ZONES...WITH THE
SEA BREEZE HAVING CLEARED OUR NW TIER. IN ITS WAKE A STABILIZED
ENVIRONMENT HAS ENSUED AND WILL PERSIST.
FOR TONIGHT... THERE IS SOME CHANGES THAT WILL TAKE PLACE IN THE
LARGER SCALE...AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA COAST
TO GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE MISSISSIPPI
VALLEY SHIFTS EAST. AS THIS TRANSPIRES...IT FORCES THE LAST GRIPS OF
THE ATLANTIC RIDGE TO PULL OFFSHORE AFTER MIDNIGHT...AS A
PRE-FRONTAL TROUGH IN EASTERN ALABAMA AND WESTERN GEORGIA APPROACHES
LATE. THE FORECAST AREA WILL THEN LIE SANDWICHED BETWEEN THE FIRST
SHORT WAVE IN THE NEARBY ATLANTIC AND THE SECOND IMPULSE AND ITS
REFLECTION AT THAT SURFACE. WHILE THERE IS SOME INCREASE IN LOW
LEVEL CONVERGENCE TO THE EAST...THE SYNOPTIC FLOW MAY VEER TOO FAR
TO THE SW TO ALLOW FOR ANYTHING MORE THAN LOW END POPS OVER
CHARLESTON COUNTY CLOSE TO DAYBREAK. UPSTREAM IT APPEARS THAT THE
BEST FORCING WILL STAY TO THE WEST...SO LESS THAN 14 POPS HAVE BEEN
FORECAST ELSEWHERE.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE OPTED TO ADD PATCHY FOG TO OUR NW
TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR CROSS-OVER
TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
WHILE WE HAVE MAINTAINED PREVAILING VFR THROUGH 00Z FRIDAY...THERE
IS THE RISK OF MVFR CONDITIONS IN LIGHT FOG/STRATUS A FEW HOURS
EITHER SIDE OF DAYBREAK...AND ALSO MARGINAL MVFR CONDITIONS IN
ISOLATED TO SCATTERED SHRA/TSRA WITH A PRE-FRONTAL TROUGH IN THE
LATE MORNING THROUGH MID AFTERNOON. IF THE TROUGH IS QUICKER THAN
ANTICIPATED THERE COULD BE SOME GUSTY WINDS LATE IN THE TAF CYCLE.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE DROPPING OFF TO 10 OR LESS LATE. SEAS WON/T
CHANGE MUCH...AVERAGING 2-4 FT AND HIGHEST ACROSS THE OUTER GA
WATERS. WE/LL NEED TO MONITOR FOR SOME GUSTY SHOWERS/T-STORMS
OVERNIGHT AS LOW LEVEL CONVERGENCE INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCHS 222334
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
734 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
QUITE A CHANGE IN THE PATTERN SINCE YESTERDAY...WITH MUCH OF THE
AREA VOID OF ANY CONVECTION EARLIER TODAY. WE/RE FINISHED FOR THE
EVENING FOR ANY SHOWERS OR T-STORMS IN THE LOCAL ZONES...WITH THE
SEA BREEZE HAVING CLEARED OUR NW TIER. IN ITS WAKE A STABILIZED
ENVIRONMENT HAS ENSUED AND WILL PERSIST.
FOR TONIGHT... THERE IS SOME CHANGES THAT WILL TAKE PLACE IN THE
LARGER SCALE,,,AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA
COAST TO GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE
MISSISSIPPI VALLEY SHIFTS EAST. AS THIS TRANSPIRES...IT FORCES
THE LAST GRIPS OF THE ATLANTIC RIDGE TO PULL OFFSHORE AFTER
MIDNIGHT...AS A PRE-FRONTAL TROUGH IN EASTERN ALABAMA AND WESTERN
GEORGIA APPROACHES LATE. THE FORECAST AREA WILL THEN LIE
SANDWICHED BETWEEN THE FIRST SHORT WAVE IN THE NEARBY ATLANTIC AND
THE SECOND IMPULSE AND ITS REFLECTION AT THAT SURFACE. WHILE THERE
IS SOME INCREASE IN LOW LEVEL CONVERGENCE TO THE EAST...THE
SYNOPTIC FLOW MAY VEER TOO FAR TO THE SW TO ALLOW FOR ANYTHING
MORE THAN LOW END POPS OVER CHARLESTON COUNTY CLOSE TO DAYBREAK.
UPSTREAM IT APPEARS THAT THE BEST FORCING WILL STAY TO THE
WEST...SO LESS THAN 14 POPS HAVE BEEN FORECAST ELSEWHERE.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE OPTED TO ADD PATCHY FOG TO OUR NW
TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR CROSS-OVER
TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
WHILE WE HAVE MAINTAINED PREVAILING VFR THROUGH 00Z FRIDAY...THERE
IS THE RISK OF MVFR CONDITIONS IN LIGHT FOG/STRATUS A FEW HOURS
EITHER SIDE OF DAYBREAK...AND ALSO MARGINAL MVFR CONDITIONS IN
ISOLATED TO SCATTERED SHRA/TSRA WITH A PRE-FRONTAL TROUGH IN THE
LATE MORNING THROUGH MID AFTERNOON. IF THE TROUGH IS QUICKER THAN
ANTICIPATED THERE COULD BE SOME GUSTY WINDS LATE IN THE TAF CYCLE.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE DROPPING OFF TO 10 OR LESS LATE. SEAS WON/T
CHANGE MUCH...AVERAGING 2-4 FT AND HIGHEST ACROSS THE OUTER GA
WATERS. WE/LL NEED TO MONITOR FOR SOME GUSTY SHOWERS/T-STORMS
OVERNIGHT AS LOW LEVEL CONVERGENCE INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 222323
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
723 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
LESS MOISTURE THIS AFTERNOON THAN YESTERDAY...AND RESULTING
INSTABILITY WEAKER. SHOWERS ALONG SEA BREEZE FRONT WEAKENING AS
THEY MOVE INTO MIDLANDS. STRONGER CONVECTION IN NORTH
GEORGIA/UPSTATE BUT LITTLE MOVEMENT INTO MIDLANDS. WILL CUT POPS
BACK FROM PREVIOUS FORECAST...SLIGHT CHANCE REST OF AFTERNOON AND EVENING.
SKIES WILL BECOME MOSTLY CLOUDY TONIGHT AS THE FRONT APPROACHES
FROM THE WEST WITH CHANCES OF SHOWERS INCREASING FROM WEST TO EAST
DURING THE PRE-DAWN HOURS. OVERNIGHT LOWS WILL GENERALLY BE IN THE
MID 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIR MASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE MIDLANDS. WILL
RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST ON
THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE THE
COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
RADAR INDICATES CONVECTIVE ACTIVITY AT A MINIMUM ACROSS OUR FA. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC AND N/CENT GA. HIGH
RES MODELS INDICATE ACTIVITY DEVELOPING TO OUR WEST NEAR AN UPPER
IMPULSE AND SURFACE TROUGH...WEAKENING AS IT MOVES EAST AND
APPROACHES THE FA LATE TONIGHT. GUIDANCE INDICATING CIG RESTRICTIONS
LATE TONIGHT...IN A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW. FOR
NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL MONITOR LATEST
GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED. UPPER IMPULSE
AND SURFACE TROUGH WILL MOVE THROUGH THURSDAY...POSSIBLY LEADING
TO SCT SHRA/TSRA...BUT CHANCES TOO LOW...ALONG WITH SOME TIMING
QUESTIONS...TO INCLUDE MENTION IN THE TAF AT THIS TIME.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 222126
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
526 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
LESS MOISTURE THIS AFTERNOON THAN YESTERDAY...AND RESULTING
INSTABILITY WEAKER. SHOWERS ALONG SEA BREEZE FRONT WEAKENING AS
THEY MOVE INTO MIDLANDS. STRONGER CONVECTION IN NORTH
GEORGIA/UPSTATE BUT LITTLE MOVEMENT INTO MIDLANDS. WILL CUT POPS
BACK FROM PREVIOUS FORECAST...SLIGHT CHANCE REST OF AFTERNOON AND EVENING.
SKIES WILL BECOME MOSTLY CLOUDY TONIGHT AS THE FRONT APPROACHES
FROM THE WEST WITH CHANCES OF SHOWERS INCREASING FROM WEST TO EAST
DURING THE PRE-DAWN HOURS. OVERNIGHT LOWS WILL GENERALLY BE IN THE
MID 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIR MASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE MIDLANDS. WILL
RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST ON
THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE THE
COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
CURRENT MESOANALYSIS INDICATES GENERALLY MODERATE INSTABILITY OVER
THE REGION. SCATTERED SHOWERS AND A FEW THUNDERSTORMS CURRENTLY
ALONG A SEA BREEZE...BUT COVERAGE HAS BEEN DECREASING IN THE LAST
HOUR OR SO. OTHER CONVECTIVE ACTIVITY OVER THE UPSTATE AND PORTIONS
OF N/NE GA...MOVING SLOWLY. WILL EXPECT ACTIVITY TO GRADUALLY
DISSIPATE AND NOT AFFECT TERMINALS. OBS INDICATE MAINLY SCT CU
WITH BASES ABOVE VFR. HIGH RES MODELS INDICATE MORE SIGNIFICANT
ACTIVITY DEVELOPING TO OUR WEST NEAR AN UPPER IMPULSE AND SURFACE
TROUGH...WEAKENING AS IT APPROACHES THE FA LATE TONIGHT. GUIDANCE
INDICATING CIG RESTRICTIONS LATE TONIGHT...IN A CONTINUED MOIST
SOUTHERLY LOW LEVEL FLOW. UPPER IMPULSE AND SURFACE TROUGH WILL
MOVE THROUGH THURSDAY...POSSIBLY LEADING TO SCT SHRA/TSRA...BUT
CHANCES TOO LOW...ALONG WITH SOME TIMING QUESTIONS...TO INCLUDE
MENTION IN THE TAF AT THIS TIME.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS POSSIBLE FRIDAY.
OTHERWISE...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KFFC 221950
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
350 PM EDT WED MAY 22 2013
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AFTERNOON CONVECTION EXPECTED TO INCREASE IN COVERAGE AND PERSIST
INTO THE EVENING AND OVERNIGHT HOURS AS UPPER LEVEL TROUGH MOVES
THROUGH THE MISSISSIPPI VALLEY. CONVECTION EXPECTED TO BECOME MORE
ORGANIZED AS ASSOCIATED SHORT WAVE FOCUSES DEVELOPMENT. MODELS A
LITTLE INCONSISTENT WITH THE DEVELOPMENT AND/OR PROGRESSION OF THE
ORGANIZED PRECIPITATION...BUT WITH INCREASING
INSTABILITIES...DIURNAL HEATING...AND INCREASING SHEAR ACROSS THE
AREA...FEEL THERE IS ENOUGH TO SUPPORT GOOD CHANCE TO LIKELY
POPS...ESPECIALLY ACROSS NORTH GEORGIA. HAVE CONTINUED MENTION OF
POSSIBLE SEVERE STORMS...ACCOMPANIED WITH GUSTY WINDS AND SMALL
HAIL...IN THE GRIDS THROUGH 02Z TONIGHT ACROSS NORTH
GEORGIA...GENERALLY NORTH OF THE ATL METRO AREA. HAVE ALSO
QUICKLY TAPERED OFF EVENING AND OVERNIGHT POPS INTO THURSDAY
MORNING...WITH GENERALLY SLIGHT CHANCE POPS ACROSS THE AREA THROUGH
THE DAY THURSDAY AS SHORT WAVE PUSHES INTO THE CAROLINAS.
AS PREVIOUSLY MENTIONED...THE SEVERE THREAT IS PRIMARILY CONFINED TO
NORTH GEORGIA...THOUGH STRONG STORMS CAN BE EXPECTED ACROSS MUCH OF
THE CWA. THE PRIMARY CONCERNS IN SEVERE ACTIVITY WILL BE GUSTY WINDS
TO 60 MPH OR HIGHER...1 INCH HAIL OR HIGHER...FREQUENT LIGHTNING AND
PERIODS OF HEAVY RAINFALL. GUSTY WINDS AND SMALL HAIL ARE ALSO
POSSIBLE IN THE STRONGER STORMS.
PRESSURE GRADIENT TIGHTENS THURSDAY AFTERNOON AND INTO FRIDAY...WITH
WINDS 10 TO 15 MPH WITH GUSTS NEAR 20 MPH...ESPECIALLY ACROSS NORTHERN
AND EASTERN GEORGIA.
FOR THE TEMPERATURES..HAVE GENERALLY GONE WITH A GUIDANCE BLEND.
TEMPERATURES THURSDAY MORNING ARE EXPECTED TO BE IN THE 60S...AND
DEPENDING ON THE TIMING OF THE DIMINISHING CONVECTION AND CLOUDS OUT
OF THE AREA...THIS COULD IMPACT MORNING LOWS BY A FEW DEGREES.
TEMPERATURES WILL BE BACK IN THE LOW TO MID 80S THURSDAY AFTERNOON
BEFORE COOLING BY FRIDAY.
31
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO MAJOR CHANGES MADE TO THE EXTENDED PORTION OF THE FORECAST. A MUCH
DRIER AIRMASS MOVES OVER THE AREA FRIDAY WITH DRY NW FLOW ALOFT
AND SURFACE HIGH PRESSURE BUILDING OVER THE OH/TN VALLEYS DURING
THE DAY. GRADIENT WINDS WILL INCREASE GETTING CLOSE TO WIND
ADVISORY CRITERIA(20 MPH SUSTAINED) FOR SOME AREAS. DRY CONDITIONS
SHOULD CONTINUE THROUGH THE WEEKEND EVEN WITH SLIGHT DIFFERENCES
BETWEEN THE GFS AND ECMWF. THE NW FLOW ALOFT N OF THE AREA IS
EXPECTED TO BECOME MORE ACTIVE WITH INCREASED PRECIP CHANCES NORTH
OF THE STATE...BUT IT SHOULD STAY DRY ACROSS GA. LOOKS LIKE THE
BETTER MOISTURE FINALLY MOVES IN ACROSS THE AREA BY THE BEGINNING
OF NEXT WEEK SO WILL SLOWLY INCREASE CHANCES OF POPS MON THROUGH DAY
7. TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF NORMAL
THROUGH THE PERIOD EXCEPT SATURDAY ND SUNDAY MORNING LOWS ARE
RUNNING 10-15 DEGREES BELOW NORMAL.
01
&&
.AVIATION...
18Z UPDATE...
CONVECTION WILL CONTINUE TO INCREASE IN COVERAGE ACROSS THE STATE
THIS AFTERNOON AND EVENING. HAVE GENERALLY TEMPO TS FOR THE ATL
AREA AND AHN TAF SITES TO ACCOUNT FOR TS IN THE AREA THIS
AFTERNOON...AND PREVAILING TS AS MORE ORGANIZED CONVECTION MOVES
IN 00-02Z. CSG AND MCN AREAS LOOK TO BE PRIMARILY IMPACTED THIS
EVENING WITH THE MAIN CONVECTION LINE. OVERALL...ANTICIPATING VFR
CONDITIONS...WITH SOME RESTRICTED VSBYS IN THE TS. AHN COULD SEE
SCT-BKN IFR 08-13Z WITH LINGERING MOISTURE IN THE AREA. WINDS WILL
BE GENERALLY SOUTHWESTERLY THIS AFTERNOON...SWITCHING TO THE WEST
OR NORTHWEST WITH THE FRONTAL PASSAGE TONIGHT. VRB GUSTY WINDS
EXPECTED IN CONVECTION TODAY. GUSTY NW WINDS EXPECTED BY THURSDAY
AFTERNOON...GENERALLY G18-24KT.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON CONVECTION TIMING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 65 85 59 79 / 60 20 5 0
ATLANTA 66 83 59 76 / 60 10 5 0
BLAIRSVILLE 61 78 54 71 / 60 20 10 0
CARTERSVILLE 63 83 57 76 / 60 10 5 0
COLUMBUS 68 89 63 82 / 60 10 5 0
GAINESVILLE 64 82 57 75 / 60 10 5 0
MACON 65 89 60 83 / 60 20 5 0
ROME 63 84 57 77 / 50 10 5 0
PEACHTREE CITY 63 85 58 77 / 60 10 5 0
VIDALIA 68 89 65 88 / 40 20 5 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....01
AVIATION...31
000
FXUS62 KCHS 221927
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
327 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONGOING SCATTERED CONVECTION ALONG THE SEABREEZE WILL GRADUALLY
SHIFT INLAND THROUGH THE REMAINDER OF THE AFTERNOON HOURS...THEN
STEADILY DIMINISH IN COVERAGE AS THE MARGINAL INSTABILITY THIS
AFTERNOON FURTHER DECREASES WITH SUNSET. HAVE THUS INDICATED 20 TO
30 PERCENT RAIN CHANCES DECREASING FROM EAST TO WEST TOWARD THE
EVENING HOURS. LATEST MESOANALYSIS REVEALS RATHER UNIMPRESSIVE
INSTABILITY THIS AFTERNOON...AND WHEN CONSIDERING WEAK LAPSE
RATES AND VERTICAL WIND PROFILES...SEVERE THUNDERSTORM POTENTIAL
IS LOW THROUGH THIS EVENING.
THE SOUTHEAST STATES WILL BECOME LOCATED ALONG THE PERIPHERY OF A
BROAD UPPER TROUGH STRETCHING FROM THE GREAT LAKES REGION INTO THE
LOWER MISSISSIPPI VALLEY TONIGHT. SOUTH/SOUTHEAST FLOW AROUND
PERSISTENT ATLANTIC SURFACE HIGH PRESSURE WILL CONTINUE TO
SUPPORT DECENT LOW LEVEL MOISTURE OVERNIGHT. BEST INSTABILITY AND
CONVERGENCE WILL SHIFT INTO THE COASTAL WATERS AFTER
MIDNIGHT...AND NUMERICAL MODEL SOLUTIONS SUGGEST ISOLATED SHOWERS
COULD DEVELOP IN THE MARINE ZONES DURING THE EARLY MORNING HOURS.
CONSIDERING AN ONSHORE COMPONENT TO THE SURFACE FLOW...THERE
REMAINS A SLIGHT CHANCE THAT SHOWERS COULD SHIFT LOCALLY ONSHORE
MAINLY ALONG THE CHARLESTON COUNTY COASTLINE. A COLD FRONT WILL
ALSO BE APPROACHING FROM THE WEST...AND A PRE FRONTAL TROUGH
FEATURE WILL ENHANCE MOISTURE/CONVERGENCE DOWNSTREAM...PERHAPS
SUPPORTING THE INTRUSION OF SHOWERS INTO FAR INLAND ZONES JUST
BEFORE SUNRISE. HAVE THUS PINNED THE FORECAST AREA BETWEEN SLIGHT
CHANCE POPS TO THE WEST AND SLIGHT CHANCES ALONG THE NORTHERN
COAST BY DAYBREAK. OVERALL HOWEVER...THE MAJORITY OF THE AREA WILL
REMAIN DRY OVERNIGHT. TEMPERATURES WILL FALL INTO THE MID TO UPPER
60S.
ALTHOUGH PATCHY FOG DEVELOPMENT IS POSSIBLE AFTER MIDNIGHT...MODEL
GUIDANCE REMAINS RATHER CONSERVATIVE IN DEPICTING ANY REDUCED
VISIBILITIES. CONSIDERING SOME UNCERTAINTY IN THE POTENTIAL FOR
CLOUD COVER TO RETURN OVERNIGHT...AS WELL AS LESS RAIN COVERAGE
TODAY...PREFER TO KEEP FOG OUT OF THE FORECAST AT THIS TIME.
SUBSEQUENT FORECAST SHIFTS WILL BE ABLE TO REASSESS TRENDS WITH
THE EVENING UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR IS EXPECTED TO PREVAIL THROUGH THE AFTERNOON. SOME ISOLATED
SHOWERS COULD IMPACT MAINLY KSAV DURING THE FIRST FEW HOURS OF
THE VALID TAF PERIOD...WITH BRIEF PERIODS OF REDUCED VSBYS/CIGS
WITHIN HEAVIER RAINFALL. ACTIVITY WILL DIMINISH AFTER SUNSET. LATE
TONIGHT...RESTRICTIONS WILL BE POSSIBLE ONCE AGAIN DUE TO FOG
AND/OR STRATUS GIVEN SMALL SURFACE T/TD SPREADS...LIGHT
WINDS...AND MODEL SOUNDINGS INDICATING DECENT LOW LEVEL MOISTURE.
DUE TO LOW CONFIDENCE HAVE DECIDED TO KEEP VFR FOR NOW...BUT
SHOWED THE GENERAL DOWNWARD TREND IN THE TAF. AFTER SUNRISE...VFR
SHOULD RETURN. SHOWERS/THUNDERSTORMS WILL BE POSSIBLE IN THE
MORNING.
EXTENDED AVIATION...THERE COULD BE A BRIEF PERIOD OF MVFR/IFR IN
CONVECTION THURSDAY AFTERNOON...BUT VFR CONDITIONS ARE EXPECTED
OTHERWISE...CONTINUING INTO THE WEEKEND. THE WINDS COULD GET A BIT
GUSTY FRIDAY AFTERNOON BEHIND THE SECONDARY FRONT.
&&
.MARINE...
MARINE CONDITIONS WILL BE FAIRLY BENIGN THROUGH TONIGHT...AS THE
AREA REMAINS ON THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE.
EXPECT A GENERAL SOUTHERLY FLOW TO PREVAIL...WITH WIND SPEEDS
BELOW 15 KT.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...ECT
MARINE...FWA/WMS
TIDES/COASTAL FLOODING...
000
FXUS62 KFFC 221837
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
237 PM EDT WED MAY 22 2013
.PREV DISCUSSION... /ISSUED 745 AM EDT WED MAY 22 2013/
SHORT TERM /TODAY THROUGH THURSDAY/...
UPPER TROUGH WILL MOVE THROUGH THE UPPER MISSISSIPPI VALLEY TODAY
INTO TONIGHT. AN ASSOCIATED SHORT WAVE TRAILING INTO THE SOUTHERN
STATES WILL HELP FOCUS SHOWERS AND THUNDERSTORMS ACROSS THE CWA
THROUGH TONIGHT. AREA OF THUNDERSTORMS CURRENTLY MOVING INTO ALABAMA
MAY REACH NORTHWEST GEORGIA BY SUNRISE IF THEY HOLD TOGETHER. THIS
COMBINED WITH VARIOUS OUTFLOW BOUNDARIES WILL MAKE TIMING OF
CONVECTION DIFFICULT. HOWEVER THE BEST CHANCES WOULD SEEM TO BE THIS
AFTERNOON AND EVENING WITH DIURNAL HEATING. HAVE CONTINUED WITH THE
SEVERE WORDING ACROSS PORTIONS OF NORTH THIS AFTERNOON. THIS FITS
WELL WITH THE SPC SLIGHT RISK AREA. DIMINISHING POPS OVERNIGHT AS
THE SHORT WAVE MOVES INTO THE CAROLINAS. SOME DRYING INDICATED FOR
THURSDAY BUT WITH APPROACHING UPPER TROUGH...HAVE LEFT LOW POPS IN
ACROSS THE CWA. BASED ON TUESDAYS TEMPERATURES...HAVE STAYED ON THE
WARM SIDE OF MAV/MET. HOWEVER WITH ADDITIONAL CLOUDS AND
PRECIPITATION EXPECTED FOR TODAY...TEMPERATURES MAY VARY MORE ACROSS
THE CWA.
41
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A WEAK COLD FRONT AND MAIN UPPER SUPPORT WILL BE EXITING THE AREA
THURSDAY NIGHT. IT IS UNCLEAR HOW MUCH CONVECTIVE ACTIVITY THERE
WILL BE WITH THE GFS AND NAM INDICATING LITTLE OR NO MEASURABLE
RAIN AMOUNTS. LOOKS LIKE NO MORE THAN A SLIGHT CHANCE OF SHOWERS OR
THUNDERSTORMS FOR THE FIRST PART OF THURSDAY NIGHT.
MUCH DRIER AIRMASS MOVES OVER THE AREA ON FRIDAY WITH DRY NW FLOW
ALOFT AND SURFACE HIGH PRESSURE BUILDING OVER THE OH/TN VALLEYS
DURING THE DAY. GRADIENT WINDS WILL INCREASE GETTING CLOSE TO WIND
ADVISORY CRITERIA(20 MPH SUSTAINED) FOR SOME AREAS. DRY CONDITIONS
CONTINUE SATURDAY AND MOSTLY SUNDAY. HOWEVER THE NW FLOW ALOFT N OF
THE AREA IS BECOMING MORE ACTIVE WITH PRECIP CHANCES AND WHILE THE
GFS IS DRY FOR OUR AREA ON SUNDAY...MOISTURE IS SKIRTING NE GA. THE
EUROPEAN MEANWHILE IS INDICATING LIGHT PRECIP AMOUNTS OVER FAR N AND
E GA ON SUNDAY. A SIMILAR PATTERN CONTINUES FOR MONDAY AND TUESDAY
AS WELL. HIGH PRESSURE ALOFT BUILDS FOR WEDNESDAY AND EVEN WILL
SOUTHERLY FLOW OVER THE AREA...HIGH PRESSURE ALOFT WILL KEEP ANY
PRECIP CHANCES TO A MINIMUM. FOR NOW WILL FAVOR THE DRIER GFS.
TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH
THE PERIOD EXCEPT SATURDAY MORNING LOWS ARE RUNNING 10-15 DEGREES
BELOW NORMAL AND SUNDAY MORNING LOWS ARE RUNNING CLOSE TO 10
DEGREES BELOW NORMAL.
BDL
&&
.AVIATION...
18Z UPDATE...
CONVECTION WILL CONTINUE TO INCREASE IN COVERAGE ACROSS THE STATE
THIS AFTERNOON AND EVENING. HAVE GENERALLY TEMPO TS FOR THE ATL
AREA AND AHN TAF SITES TO ACCOUNT FOR TS IN THE AREA THIS
AFTERNOON...AND PREVAILING TS AS MORE ORGANIZED CONVECTION MOVES
IN 00-02Z. CSG AND MCN AREAS LOOK TO BE PRIMARILY IMPACTED THIS
EVENING WITH THE MAIN CONVECTION LINE. OVERALL...ANTICIPATING VFR
CONDITIONS...WITH SOME RESTRICTED VSBYS IN THE TS. AHN COULD SEE
SCT-BKN IFR 08-13Z WITH LINGERING MOISTURE IN THE AREA. WINDS WILL
BE GENERALLY SOUTHWESTERLY THIS AFTERNOON...SWITCHING TO THE WEST
OR NORTHWEST WITH THE FRONTAL PASSAGE TONIGHT. VRB GUSTY WINDS
EXPECTED IN CONVECTION TODAY. GUSTY NW WINDS EXPECTED BY THURSDAY
AFTERNOON...GENERALLY G18-24KT.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON CONVECTION TIMING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 65 85 59 / 40 60 20 5
ATLANTA 86 66 83 59 / 50 60 10 5
BLAIRSVILLE 80 61 78 54 / 60 60 20 10
CARTERSVILLE 84 63 83 57 / 60 60 10 5
COLUMBUS 90 68 89 63 / 40 60 10 5
GAINESVILLE 85 64 82 57 / 70 60 10 5
MACON 90 65 89 60 / 50 60 20 5
ROME 84 63 84 57 / 70 50 10 5
PEACHTREE CITY 86 63 85 58 / 50 60 10 5
VIDALIA 88 68 89 65 / 30 40 20 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....01
AVIATION...31
000
FXUS62 KCAE 221829
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
229 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE OFF THE ATLANTIC COAST CONTINUES TO PUSH MOISTURE
INTO THE FORECAST AREA WITH SATELLITE IMAGERY SHOWING CUMULUS
DEVELOPING ACROSS THE REGION. CAE WSR-88D RETURNS SHOWS SHOWERS
DEVELOPING THROUGH THE CSRA AS WELL AS ACTIVITY ALONG THE
INTENSIFYING SEA BREEZE. EXPECT THE SHOWERS TO INCREASE IN
COVERAGE OVER THE NEXT COUPLE OF HOURS...WITH SOME BECOMING
THUNDERSTORMS. SEVERE THREAT REMAINS LOW WITH ISOLATED HAIL AND
GUSTY WINDS THE MAIN CONCERNS. CONVECTION WILL DIMINISH WITH LOSS
OF HEATING THIS EVENING AND CEASE OVERNIGHT. SKIES WILL REMAIN
MOSTLY CLOUDY THROUGH THE NIGHT AS THE FRONT APPROACHES FROM THE
WEST WITH CHANCES OF SHOWERS INCREASING FROM WEST TO EAST DURING
THE PRE-DAWN HOURS. OVERNIGHT LOWS WILL GENERALLY BE IN THE MID
60S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIRMASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE MIDLANDS. WILL
RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST ON
THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE THE
COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS THROUGH THE TAF PERIOD.
SATELLITE IMAGERY SHOWS THE STRATUS ASSOCIATED WITH MORNING FOG
HAS BURNED OFF WITH CUMULUS DEVELOPING AS TEMPERATURES RISING INTO
THE LOWER 80S. WSR-88D IMAGERY SHOWS SHOWERS TO THE SOUTHWEST OF
AGS/DNL WITH ADDITIONAL SHOWERS ALONG THE DEVELOPING SEA BREEZE
TOWARD THE COAST. EXPECT THE SHOWERS TO INCREASE IN COVERAGE OVER
THE NEXT COUPLE OF HOURS WITH SOME INTENSIFYING INTO
THUNDERSTORMS. AS SUCH HAVE INCLUDED A TEMPO FOR SHOWERS IN THE
AGS/DNL AREA WHILE CONFIDENCE IN OTHER LOCATIONS REMAINS TOO LOW
ATTM. OVERNIGHT FOG DEVELOPMENT THREAT ALSO REMAINS LOW AS THE
COLD FRONT APPROACHES FROM THE WEST PREVENTING A STRONG INVERSION
FROM DEVELOPING. FRONT WILL CROSS THE AREA THURSDAY MORNING AND
WITH THE FRONT WEAKENING AS IT MOVES INTO THE AREA CONFIDENCE IN
RAIN WITH THE FRONT IS LOW.
EXTENDED AVIATION OUTLOOK...
INCREASING CONFIDENCE IN STRONG AND GUSTY WINDS FRIDAY LATE
MORNING INTO FRIDAY EVENING.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 221741
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
141 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE WEAK UPPER LEVEL PATTERN WILL GRADUALLY TRANSITION TODAY...AS
THE BAGGY TROUGH OVER THE SOUTHEAST STATES BECOMES MORE ABSORBED
INTO THE PERIPHERY OF A STRONGER TROUGH CURRENTLY OVER THE
MISSISSIPPI VALLEY. DEEP MOISTURE STILL LINGERS OVER THE
AREA...SEEN IN VERTICAL SOUNDINGS WITH PRECIPITABLE WATER VALUES
AROUND 1.5 INCHES. WITH THE FORECAST AREA STILL UNDER THE
INFLUENCE OF ATLANTIC SURFACE HIGH PRESSURE...SOUTH/SOUTHEAST
FLOW WILL PREVAIL AND HAS ALLOWED THE SEABREEZE TO DEVELOP EARLY.
SEABREEZE FORCING WITHIN ABUNDANT MOISTURE HAS SUPPORTED THE
INITIATION OF ISOLATED TO SCATTERED SHOWERS.
LACKING ANY OTHER NOTABLE FORCING MECHANISMS...CONVECTIVE
DEVELOPMENT AND EVOLUTION TODAY IS MAINLY DRIVEN BY THE SEABREEZE
PROGRESSION AND TYPICAL DIURNAL HEATING AND INSTABILITY. THE
PRECIPITATION FORECAST WILL THUS INDICATE SHOWERS CURRENTLY ALONG
THE SEABREEZE SPREADING INLAND AS THE AFTERNOON PROGRESSES. HAVE
MAINTAINED RAIN CHANCES IN THE 20 TO 30 PERCENT RANGE. LATEST
MESOANALYSIS REVEALS RATHER UNIMPRESSIVE INSTABILITY BY EARLY
AFTERNOON...AND WHEN CONSIDERING WEAK LAPSE RATES AND VERTICAL
WIND PROFILES...SEVERE THUNDERSTORM POTENTIAL APPEARS LOW. IN
FACT...ONGOING CONVECTION HAS STRUGGLED TO PRODUCE LIGHTNING BY 1
PM EDT. HOWEVER...AS COMMON THIS TIME OF YEAR...AN ISOLATED STRONG
TO SEVERE THUNDERSTORM CANNOT BE RULED OUT WHERE BOUNDARY
INTERACTIONS OCCUR. OTHERWISE...THE MAIN HAZARD ASSOCIATED WITH
SHOWERS/THUNDERSTORMS WILL BE HEAVY DOWNPOURS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
DIURNAL CONVECTION WILL TAPER OFF EARLY THIS EVENING OVER
LAND...WHILE ISOLATED SHOWERS OR STORMS WILL REMAIN POSSIBLE OVER
THE COASTAL WATERS TONIGHT. SOME FOG IS POSSIBLE LATE
TONIGHT/EARLY THURSDAY MORNING...ESPECIALLY IN AREAS WHERE RAIN
OCCURS TODAY.
THURSDAY...ATLANTIC HIGH PRESSURE WILL PREVAIL WHILE WEAK TROUGHING
PERSISTS INLAND. A SHORTWAVE EMBEDDED WITHIN BROAD UPPER LEVEL
TROUGHING WILL CROSS THE REGION AND PUSH THE DEEP LAYERED MOISTURE
OFFSHORE AS THE DAY PROGRESSES. THERE IS THE POTENTIAL FOR ISOLATED
CONVECTION ACROSS THE AREA IN THE MORNING AHEAD OF THE SHORT
WAVE...WITH THE COVERAGE INCREASING TO SCATTERED IN THE AFTERNOON
ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA WHERE PRECIPITABLE WATER
VALUES AND LOW LEVEL CONVERGENCE WILL BE MAXIMIZED. A
WESTERLY/DOWNSLOPE FLOW ALOFT WILL PUSH TEMPERATURES TO HIGHS IN THE
UPPER 80S TO AROUND 90 AWAY FROM THE IMMEDIATE COAST.
THURSDAY NIGHT...AN UPPER LEVEL TROUGH WILL DIG TOWARD THE
APPALACHIANS...PUSHING A COLD FRONT ACROSS THE AREA. OTHER THAN SOME
ISOLATED CONVECTION EARLY IN THE EVENING MAINLY ACROSS THE
CHARLESTON TRI-COUNTY AREA...THE FRONT SHOULD PASS THROUGH RELATIVE
RAIN-FREE DUE TO A LACK OF DEEP LAYERED MOISTURE. LOWS WILL BE IN
THE LOWER TO MID 60S.
FRIDAY...THE UPPER LEVEL TROUGH WILL MOVE OVER THE MID-ATLANTIC AS
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE GREAT LAKES REGION
IN WAKE OF THE DEPARTING COLD FRONT. MUCH DRIER AIR WILL FILTER INTO
THE AREA WITH A STRONG NORTHWEST/DOWNSLOPE WIND COMPONENT. THERE
WILL BE CONSIDERABLE SUNSHINE ALONG WITH BREEZY CONDITIONS IN THE
AFTERNOON. THE DOWNSLOPE FLOW WILL NEGATE MUCH OF THE COLD AIR
ADVECTION...ALLOWING TEMPERATURES TO REACH HIGHS IN THE MID AND
UPPER 80S ACROSS THE AREA AWAY FROM THE IMMEDIATE COAST.
FRIDAY NIGHT...RADIATIONAL COOLING WILL BE LIMITED BY A COUPLED
NORTHERLY FLOW THROUGH MUCH OF THE NIGHT...BUT THE DRY AIR MASS AND
CLEAR SKIES SHOULD STILL ALLOW TEMPERATURES TO FALL INTO THE THE MID
AND UPPER 50S...WITH SOME LOWER 50S POSSIBLE WELL INLAND.
SATURDAY...AN EXTREMELY DRY AIR MASS WILL BE IN PLACE TO START THE
WEEKEND...WITH PRECIPITABLE WATER VALUES AS LOW AS .25 TO .50 INCHES
WHICH IS MORE THAN 2 STANDARD DEVIATIONS BELOW NORMAL FOR THIS TIME
OF YEAR. GIVEN THIS DRY AIR MASS...THERE WILL BE CONSIDERABLE
SUNSHINE BUT A NORTH-NORTHEAST FLOW WILL LIMIT HIGHS TO THE UPPER
70S TO LOWER 80S ACROSS SOUTHEAST SOUTH CAROLINA AND THE LOWER TO
MID 80S ACROSS SOUTHEAST GEORGIA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR IS EXPECTED TO PREVAIL THROUGH THE AFTERNOON. SOME ISOLATED
SHOWERS COULD IMPACT MAINLY KSAV DURING THE FIRST FEW HOURS OF
THE VALID TAF PERIOD...WITH BRIEF PERIODS OF REDUCED VSBYS/CIGS
WITHIN HEAVIER RAINFALL. ACTIVITY WILL DIMINISH AFTER SUNSET. LATE
TONIGHT...RESTRICTIONS WILL BE POSSIBLE ONCE AGAIN DUE TO FOG
AND/OR STRATUS GIVEN SMALL SURFACE T/TD SPREADS...LIGHT
WINDS...AND MODEL SOUNDINGS INDICATING DECENT LOW LEVEL MOISTURE.
DUE TO LOW CONFIDENCE HAVE DECIDED TO KEEP VFR FOR NOW...BUT
SHOWED THE GENERAL DOWNWARD TREND IN THE TAF. AFTER SUNRISE...VFR
SHOULD RETURN. SHOWERS/THUNDERSTORMS WILL BE POSSIBLE IN THE
MORNING.
EXTENDED AVIATION...ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH
THURSDAY. A COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT
WITH HIGH PRESSURE THEN BUILDING OVER THE REGION THROUGH EARLY
NEXT WEEK.
&&
.MARINE...
MARINE CONDITIONS WILL BE FAIRLY BENIGN THROUGH TONIGHT...AS THE
AREA REMAINS ON THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE.
THE SEABREEZE WILL DEVELOP BY LATE MORNING...HOWEVER WIND SPEEDS
AT THE COAST ARE STILL EXPECTED TO GENERALLY REMAIN BELOW 15 KT.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...JAQ
LONG TERM...JAQ
AVIATION...ECT
MARINE...JAQ/JRL
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 221512
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1112 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...SATELLITE IMAGERY AND SURFACE OBS SHOW FOG CONTINUES TO
LIFT ACROSS THE AREA WITH LOW CLOUDS CONTINUING TO LINGER ACROSS
MUCH OF THE AREA. EXPECT THE CLOUDS TO BREAK UP A BIT PRODUCING
PARTLY SUNNY SKIES DURING THE LATE MORNING TO EARLY AFTERNOON
HOURS. WITH HIGH PRESSURE OFFSHORE AND SOUTHERLY WINDS PERSISTING
OVER THE AREA THERE WILL BE ANOTHER CHANCE OF AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS. THE MAIN THREAT WILL AGAIN BE
HEAVY RAIN AS PWAT VALUES REMAIN 1.6 INCHES OR GREATER. SEVERE
THUNDERSTORM POTENTIAL REMAINS LOW...HOWEVER AN ISOLATED SEVERE
CELL IS POSSIBLE WITH GUSTY WINDS AND LARGE HAIL. WITH THE CLOUD
COVER ACROSS THE FORECAST AREA THIS MORNING HAVE LOWERED HIGH
TEMPERATURES A DEGREE OR TWO WITH AFTERNOON HIGH TEMPERATURES IN
THE MIDDLE 80S.
PREVIOUS DISCUSSION...HIGH PRESSURE OFF THE SOUTHEAST COAST WILL
CONTINUE TO CIRCULATE MOIST AIR INTO THE FORECAST AREA TODAY. THE
NAM AND GFS CONTINUE TO INDICATE A WEAK MID-LEVEL SHORTWAVE TROUGH
LINGERING OVER THE FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS
MAINLY DURING THE TIME OF MAXIMUM HEATING. USED AN AVERAGE OF THE
GFS AND NAM MOS POPS. PRECIPITABLE WATER NEAR 1.7 OF AN INCH AND
SLOW STORM MOVEMENT SUPPORTS HEAVY RAIN WILL SOME OF THE
THUNDERSTORMS. HEAVY PRECIPITATION LOADINGS AND POSSIBLY MODERATE
INSTABILITY WITH H5 TEMPERATURES AROUND -10 SUPPORT A POSSIBILITY
OF DAMAGING WIND. USED THE WARMER TEMPERATURE GUIDANCE FOR TODAY
BASED ON YESTERDAY/S VERIFICATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
A CONTINUED MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH
PLUS A PRE-FRONTAL TROUGH SUPPORT THUNDERSTORMS TONIGHT. COVERAGE
WILL LIKELY BE LIMITED BY DIURNAL COOLING AND PREVIOUS CONVECTION.
THE NAM AND GFS MOS ARE IN GOOD AGREEMENT WITH POPS 30 TO 40 PERCENT.
THE MODELS SHOW THE PRE-FRONTAL TROUGH LINGERING THURSDAY BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE FORECAST AREA EARLY
AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE NAM AND GFS MOS
INDICATE VERY LOW POPS...BUT MAINTAINED CHANCE POPS BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE PRE-FRONTAL TROUGH THURSDAY AND
THE COLD FRONT THURSDAY EVENING. FURTHER DRYING SHOULD OCCUR
BEHIND THE FRONT BY LATE THURSDAY NIGHT. THE TEMPERATURE GUIDANCE
WAS CLOSE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
AND TUESDAY. THE GFS AND ECMWF MOS PLUS GFS ENSEMBLE MEAN SUPPORTS
VERY LOW POPS. EXPECT BELOW NORMAL TEMPERATURES DURING THE
WEEKEND AND NEAR NORMAL DURING THE REST OF THE MEDIUM RANGE
PERIOD.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
MAINLY VFR CONDITIONS THROUGH THE TAF PERIOD.
FOG HAS ERODED ACROSS THE AREA WITH SOME LOW CLOUDS
REMAINING...WHICH WILL DISSIPATE OVER THE NEXT HOUR OR SO. MAIN
CONCERN THROUGH THE PERIOD WILL BE AFTERNOON AND EVENING
CONVECTION. EXPECT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
TO DEVELOP THIS AFTERNOON AND LINGER INTO THIS EVENING. CONFIDENCE
IN COVERAGE AND TIMING REMAIN TOO LOW TO INCLUDE IN TAFS ATTM.
POTENTIAL FOR FOG OVERNIGHT REMAINS LOW AS FRONT APPROACHES FROM
THE WEST...HOWEVER WITH A 25 KNOT LOW LEVEL JET ACROSS THE AREA
LOW STRATUS WILL BE POSSIBLE. MUCH OF THE STRATUS POTENTIAL WILL
DEPEND ON AFTERNOON SHOWERS SO HAVE KEPT STRATUS OUT OF TAFS ATTM.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
THURSDAY NIGHT. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO
POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 221445
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1045 AM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE WEAK UPPER LEVEL PATTERN WILL GRADUALLY TRANSITION TODAY...AS
THE BAGGY TROUGH OVER THE SOUTHEAST STATES BECOMES MORE ABSORBED
INTO THE PERIPHERY OF A STRONGER TROUGH CURRENTLY OVER THE
MISSISSIPPI VALLEY. DEEP MOISTURE STILL LINGERS OVER THE
AREA...SEEN IN VERTICAL SOUNDINGS WITH PRECIPITABLE WATER VALUES
AROUND 1.5 INCHES. WITH THE FORECAST AREA STILL UNDER THE
INFLUENCE OF ATLANTIC SURFACE HIGH PRESSURE...SOLID SOUTHERLY FLOW
WILL PREVAIL AND HAS ALLOWED THE SEABREEZE TO DEVELOP EARLY.
SEABREEZE FORCING BY LATE MORNING WITHIN ABUNDANT MOISTURE HAS
ALREADY SUPPORTED THE INITIATION OF ISOLATED SHOWERS ACROSS
COASTAL COUNTIES BY 10 AM EDT.
LACKING ANY OTHER NOTABLE FORCING MECHANISMS...CONVECTIVE
DEVELOPMENT AND EVOLUTION TODAY IS EXPECTED TO BE MAINLY DRIVEN
BY THE SEABREEZE PROGRESSION AND TYPICAL DIURNAL HEATING AND
INSTABILITY. THE PRECIPITATION FORECAST WILL THUS INDICATE
THUNDERSTORMS DEVELOPING ALONG AND INLAND OF THE SEABREEZE BY LATE
MORNING...THEN SPREADING INLAND INTO THE AFTERNOON HOURS. HAVE
MAINTAINED RAIN CHANCES IN THE 20 TO 30 PERCENT RANGE. MODIFYING
THE MORNING SOUNDING AT KCHS FOR HIGH TEMPERATURES IN THE MID TO
UPPER 80S STILL INDICATES RATHER UNIMPRESSIVE INSTABILITY BY THIS
AFTERNOON...AND WHEN CONSIDERING WEAK LAPSE RATES AND VERTICAL
WIND PROFILES...SEVERE THUNDERSTORM POTENTIAL APPEARS LOW.
HOWEVER...AS COMMON THIS TIME OF YEAR...AN ISOLATED STRONG TO
SEVERE THUNDERSTORM CANNOT BE RULED OUT WHERE BOUNDARY
INTERACTIONS OCCUR. OTHERWISE...THE MAIN HAZARD ASSOCIATED WITH
THUNDERSTORMS WILL BE HEAVY DOWNPOURS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
DIURNAL CONVECTION WILL TAPER OFF EARLY THIS EVENING OVER
LAND...WHILE ISOLATED SHOWERS OR STORMS WILL REMAIN POSSIBLE OVER
THE COASTAL WATERS TONIGHT. SOME FOG IS POSSIBLE LATE
TONIGHT/EARLY THURSDAY MORNING...ESPECIALLY IN AREAS WHERE RAIN
OCCURS TODAY.
THURSDAY...ATLANTIC HIGH PRESSURE WILL PREVAIL WHILE WEAK TROUGHING
PERSISTS INLAND. A SHORTWAVE EMBEDDED WITHIN BROAD UPPER LEVEL
TROUGHING WILL CROSS THE REGION AND PUSH THE DEEP LAYERED MOISTURE
OFFSHORE AS THE DAY PROGRESSES. THERE IS THE POTENTIAL FOR ISOLATED
CONVECTION ACROSS THE AREA IN THE MORNING AHEAD OF THE SHORT
WAVE...WITH THE COVERAGE INCREASING TO SCATTERED IN THE AFTERNOON
ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA WHERE PRECIPITABLE WATER
VALUES AND LOW LEVEL CONVERGENCE WILL BE MAXIMIZED. A
WESTERLY/DOWNSLOPE FLOW ALOFT WILL PUSH TEMPERATURES TO HIGHS IN THE
UPPER 80S TO AROUND 90 AWAY FROM THE IMMEDIATE COAST.
THURSDAY NIGHT...AN UPPER LEVEL TROUGH WILL DIG TOWARD THE
APPALACHIANS...PUSHING A COLD FRONT ACROSS THE AREA. OTHER THAN SOME
ISOLATED CONVECTION EARLY IN THE EVENING MAINLY ACROSS THE
CHARLESTON TRI-COUNTY AREA...THE FRONT SHOULD PASS THROUGH RELATIVE
RAIN-FREE DUE TO A LACK OF DEEP LAYERED MOISTURE. LOWS WILL BE IN
THE LOWER TO MID 60S.
FRIDAY...THE UPPER LEVEL TROUGH WILL MOVE OVER THE MID-ATLANTIC AS
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE GREAT LAKES REGION
IN WAKE OF THE DEPARTING COLD FRONT. MUCH DRIER AIR WILL FILTER INTO
THE AREA WITH A STRONG NORTHWEST/DOWNSLOPE WIND COMPONENT. THERE
WILL BE CONSIDERABLE SUNSHINE ALONG WITH BREEZY CONDITIONS IN THE
AFTERNOON. THE DOWNSLOPE FLOW WILL NEGATE MUCH OF THE COLD AIR
ADVECTION...ALLOWING TEMPERATURES TO REACH HIGHS IN THE MID AND
UPPER 80S ACROSS THE AREA AWAY FROM THE IMMEDIATE COAST.
FRIDAY NIGHT...RADIATIONAL COOLING WILL BE LIMITED BY A COUPLED
NORTHERLY FLOW THROUGH MUCH OF THE NIGHT...BUT THE DRY AIR MASS AND
CLEAR SKIES SHOULD STILL ALLOW TEMPERATURES TO FALL INTO THE THE MID
AND UPPER 50S...WITH SOME LOWER 50S POSSIBLE WELL INLAND.
SATURDAY...AN EXTREMELY DRY AIR MASS WILL BE IN PLACE TO START THE
WEEKEND...WITH PRECIPITABLE WATER VALUES AS LOW AS .25 TO .50 INCHES
WHICH IS MORE THAN 2 STANDARD DEVIATIONS BELOW NORMAL FOR THIS TIME
OF YEAR. GIVEN THIS DRY AIR MASS...THERE WILL BE CONSIDERABLE
SUNSHINE BUT A NORTH-NORTHEAST FLOW WILL LIMIT HIGHS TO THE UPPER
70S TO LOWER 80S ACROSS SOUTHEAST SOUTH CAROLINA AND THE LOWER TO
MID 80S ACROSS SOUTHEAST GEORGIA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
ISOLATED CONVECTION IS EXPECTED TO DEVELOP IN THE VICINITY OF THE
TERMINALS BY LATE MORNING/EARLY AFTERNOON ALONG THE SEA
BREEZE...THEN SHIFT INLAND OF THE TERMINALS LATER THIS AFTERNOON.
COVERAGE/TIMING UNCERTAINTIES PRECLUDE ANY MENTION IN THE TAFS
OTHER THAN VICINITY SHOWERS THROUGH MID-AFTERNOON AT KCHS AND LATE
AFTERNOON AT KSAV. ABUNDANT LOW LEVEL MOISTURE COULD RESULT IN
SOME REDUCED CEILINGS/VISIBILITIES LATE TONIGHT.
EXTENDED AVIATION...ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH
THURSDAY. A COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT
WITH HIGH PRESSURE THEN BUILDING OVER THE REGION THROUGH EARLY
NEXT WEEK.
&&
.MARINE...
MARINE CONDITIONS WILL BE FAIRLY BENIGN THROUGH TONIGHT...AS THE
AREA REMAINS ON THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE.
THE SEABREEZE WILL DEVELOP BY LATE MORNING...HOWEVER WIND SPEEDS
AT THE COAST ARE STILL EXPECTED TO GENERALLY REMAIN BELOW 15 KT.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...JAQ
LONG TERM...JAQ
AVIATION...JAQ
MARINE...JAQ/JRL
TIDES/COASTAL FLOODING...WMS
000
FXUS62 KCAE 221419
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1019 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE
MOIST AIR INTO THE FORECAST AREA THIS AFTERNOON. THE NAM AND GFS
CONTINUE TO INDICATE A WEAK MID-LEVEL SHORTWAVE TROUGH LINGERING
OVER THE FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS MAINLY
DURING THE TIME OF MAXIMUM HEATING. USED AN AVERAGE OF THE GFS AND
NAM MOS POPS. PRECIPITABLE WATER NEAR 1.7 OF AN INCH AND SLOW
STORM MOVEMENT SUPPORTS HEAVY RAIN WILL SOME OF THE THUNDERSTORMS.
HEAVY PRECIPITATION LOADINGS AND POSSIBLY MODERATE INSTABILITY
WITH H5 TEMPERATURES AROUND -10 SUPPORT A POSSIBILITY OF DAMAGING
WIND. USED THE WARMER TEMPERATURE GUIDANCE FOR THIS AFTERNOON BASED
ON YESTERDAY/S VERIFICATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
A CONTINUED MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH
PLUS A PRE-FRONTAL TROUGH SUPPORT THUNDERSTORMS TONIGHT. COVERAGE
WILL LIKELY BE LIMITED BY DIURNAL COOLING AND PREVIOUS CONVECTION.
THE NAM AND GFS MOS ARE IN GOOD AGREEMENT WITH POPS 30 TO 40 PERCENT.
THE MODELS SHOW THE PRE-FRONTAL TROUGH LINGERING THURSDAY BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE FORECAST AREA EARLY
AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE NAM AND GFS MOS
INDICATE VERY LOW POPS...BUT MAINTAINED CHANCE POPS BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE PRE-FRONTAL TROUGH THURSDAY AND
THE COLD FRONT THURSDAY EVENING. FURTHER DRYING SHOULD OCCUR
BEHIND THE FRONT BY LATE THURSDAY NIGHT. THE TEMPERATURE GUIDANCE
WAS CLOSE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
AND TUESDAY. THE GFS AND ECMWF MOS PLUS GFS ENSEMBLE MEAN SUPPORTS
VERY LOW POPS. EXPECT BELOW NORMAL TEMPERATURES DURING THE
WEEKEND AND NEAR NORMAL DURING THE REST OF THE MEDIUM RANGE
PERIOD.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
EXPECT PERIODS OF MVFR/IFR AT MOST OF THE TAF SITES UNTIL AROUND 16Z.
STRATUS EXPECTED TO LIFT/DIMINISH BY MIDDAY. LOW LEVEL MOISTURE
WILL REMAIN HIGH. MAINLY VFR CONDITIONS THIS AFTERNOON WITH
SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z. GIVEN THE EXPECTED
SCATTERED NATURE OF THE CONVECTION...NOT ENOUGH CONFIDENCE TO
MENTION THUNDER IN THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND THUNDERSTORMS...
MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH FRIDAY. LATE NIGHT/EARLY
MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 221318
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
918 AM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK UPPER TROUGH WILL PERSIST OVER THE REGION AGAIN
TODAY...WHILE ATLANTIC SURFACE HIGH PRESSURE EXTENDS INTO THE
SOUTHEAST STATES. DEEP LAYER MOISTURE REMAINS IN PLACE...WITH
PRECIPITABLE WATER VALUES AROUND 1.5 INCHES ACCORDING TO THE
UPPER AIR SOUNDINGS AT CHS AND JAX. DEEP LAYERED SOUTHERLY FLOW
WILL ALLOW THE SEABREEZE TO DEVELOP FAIRLY EARLY. WITH
TEMPERATURES PEAKING IN THE MID TO UPPER 80S...MODERATE
INSTABILITY WILL DEVELOP BY LATE MORNING/EARLY AFTERNOON. SHOWERS
AND THUNDERSTORMS WILL THUS INCREASE IN COVERAGE FROM LATE MORNING
INTO THE AFTERNOON...WITH THE ACTIVITY LIKELY SHIFTING GRADUALLY
INLAND FOLLOWING THE MOVEMENT OF THE SEABREEZE. CONVECTIVE
PARAMETERS ARE NOT IMPRESSIVE...HOWEVER AN ISOLATED SEVERE STORM
CANNOT BE RULED OUT WHERE BOUNDARY INTERACTIONS OCCUR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
DIURNAL CONVECTION WILL TAPER OFF EARLY THIS EVENING OVER
LAND...WHILE ISOLATED SHOWERS OR STORMS WILL REMAIN POSSIBLE OVER
THE COASTAL WATERS TONIGHT. SOME FOG IS POSSIBLE LATE
TONIGHT/EARLY THURSDAY MORNING...ESPECIALLY IN AREAS WHERE RAIN
OCCURS TODAY.
THURSDAY...ATLANTIC HIGH PRESSURE WILL PREVAIL WHILE WEAK TROUGHING
PERSISTS INLAND. A SHORTWAVE EMBEDDED WITHIN BROAD UPPER LEVEL
TROUGHING WILL CROSS THE REGION AND PUSH THE DEEP LAYERED MOISTURE
OFFSHORE AS THE DAY PROGRESSES. THERE IS THE POTENTIAL FOR ISOLATED
CONVECTION ACROSS THE AREA IN THE MORNING AHEAD OF THE SHORT
WAVE...WITH THE COVERAGE INCREASING TO SCATTERED IN THE AFTERNOON
ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA WHERE PRECIPITABLE WATER
VALUES AND LOW LEVEL CONVERGENCE WILL BE MAXIMIZED. A
WESTERLY/DOWNSLOPE FLOW ALOFT WILL PUSH TEMPERATURES TO HIGHS IN THE
UPPER 80S TO AROUND 90 AWAY FROM THE IMMEDIATE COAST.
THURSDAY NIGHT...AN UPPER LEVEL TROUGH WILL DIG TOWARD THE
APPALACHIANS...PUSHING A COLD FRONT ACROSS THE AREA. OTHER THAN SOME
ISOLATED CONVECTION EARLY IN THE EVENING MAINLY ACROSS THE
CHARLESTON TRI-COUNTY AREA...THE FRONT SHOULD PASS THROUGH RELATIVE
RAIN-FREE DUE TO A LACK OF DEEP LAYERED MOISTURE. LOWS WILL BE IN
THE LOWER TO MID 60S.
FRIDAY...THE UPPER LEVEL TROUGH WILL MOVE OVER THE MID-ATLANTIC AS
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE GREAT LAKES REGION
IN WAKE OF THE DEPARTING COLD FRONT. MUCH DRIER AIR WILL FILTER INTO
THE AREA WITH A STRONG NORTHWEST/DOWNSLOPE WIND COMPONENT. THERE
WILL BE CONSIDERABLE SUNSHINE ALONG WITH BREEZY CONDITIONS IN THE
AFTERNOON. THE DOWNSLOPE FLOW WILL NEGATE MUCH OF THE COLD AIR
ADVECTION...ALLOWING TEMPERATURES TO REACH HIGHS IN THE MID AND
UPPER 80S ACROSS THE AREA AWAY FROM THE IMMEDIATE COAST.
FRIDAY NIGHT...RADIATIONAL COOLING WILL BE LIMITED BY A COUPLED
NORTHERLY FLOW THROUGH MUCH OF THE NIGHT...BUT THE DRY AIR MASS AND
CLEAR SKIES SHOULD STILL ALLOW TEMPERATURES TO FALL INTO THE THE MID
AND UPPER 50S...WITH SOME LOWER 50S POSSIBLE WELL INLAND.
SATURDAY...AN EXTREMELY DRY AIR MASS WILL BE IN PLACE TO START THE
WEEKEND...WITH PRECIPITABLE WATER VALUES AS LOW AS .25 TO .50 INCHES
WHICH IS MORE THAN 2 STANDARD DEVIATIONS BELOW NORMAL FOR THIS TIME
OF YEAR. GIVEN THIS DRY AIR MASS...THERE WILL BE CONSIDERABLE
SUNSHINE BUT A NORTH-NORTHEAST FLOW WILL LIMIT HIGHS TO THE UPPER
70S TO LOWER 80S ACROSS SOUTHEAST SOUTH CAROLINA AND THE LOWER TO
MID 80S ACROSS SOUTHEAST GEORGIA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
ISOLATED CONVECTION IS EXPECTED TO DEVELOP IN THE VICINITY OF THE
TERMINALS LATE THIS MORNING ALONG THE SEA BREEZE...THEN SHIFT
INLAND OF THE TERMINALS LATER THIS AFTERNOON. COVERAGE/TIMING
UNCERTAINTIES PRECLUDE ANY MENTION IN THE TAFS OTHER THAN
VICINITY SHOWERS THROUGH MID-AFTERNOON AT KCHS AND LATE AFTERNOON
AT KSAV. ABUNDANT LOW LEVEL MOISTURE COULD RESULT IN SOME REDUCED
CEILINGS/VISIBILITIES LATE TONIGHT.
EXTENDED AVIATION...ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH
THURSDAY. A COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT
WITH HIGH PRESSURE THEN BUILDING OVER THE REGION THROUGH EARLY
NEXT WEEK.
&&
.MARINE...
MARINE CONDITIONS LOOK PRETTY QUIET THROUGH TONIGHT AS THE AREA
REMAINS ON THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE. THE
SEABREEZE SHOULD DEVELOP LATE THIS MORNING...BUT WIND SPEEDS AT
THE COAST ARE STILL EXPECTED TO GENERALLY REMAIN BELOW 15 KT.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL MOVE ACROSS THE AREA THURSDAY NIGHT WITH HIGH PRESSURE THEN
BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS/JRL
SHORT TERM...JAQ
LONG TERM...JAQ
AVIATION...JAQ
MARINE...JAQ/JRL
TIDES/COASTAL FLOODING...
000
FXUS62 KCHS 221153
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
753 AM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL MOVE ACROSS THE AREA THURSDAY NIGHT WITH HIGH PRESSURE THEN
BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A DENSE FOG ADVISORY IS IN EFFECT FOR PARTS OF THE AREA THROUGH 9
AM AS VISIBILITIES HAVE FALLEN TO 1/4 MILE OR LESS IN AREAS MAINLY
WEST OF THE I-95 CORRIDOR. VISIBILITIES WILL GRADUALLY IMPROVE
THROUGH MID-MORNING.
WEAK SHORTWAVE TROUGHING AT UPPER LEVELS TO PERSIST TODAY WHILE
ATLANTIC HIGH PRESSURE EXTENDS WEST INTO THE SOUTHEAST STATES AT
THE SURFACE. THE IN-SITU AIRMASS REMAINS QUITE MOIST WITH PW
VALUES HOVERING AT OR ABOVE 1.60 INCHES. A FEW SHOWERS ARE
POSSIBLE OVER THE COASTAL WATERS AND IMMEDIATE SC COAST MAINLY
NORTHEAST OF CHARLESTON IN SOME WEAK MOISTURE CONVERGENCE THROUGH
MID-MORNING. THEN...THE DEEP-LAYERED SOUTHEAST FLOW WILL ALLOW
THE SEABREEZE TO DEVELOP FAIRLY EARLY. WITH TEMPS PUSHING INTO THE
MIDDLE TO UPPER 80S...MODERATE INSTABILITY WILL DEVELOP YET AGAIN.
SHOWERS AND TSTMS WILL INCREASE IN COVERAGE FROM LATE MORNING INTO
THE AFTERNOON WITH THE ACTIVITY LIKELY SHIFTING GRADUALLY INLAND.
CONVECTIVE PARAMETERS ARE NOT TERRIBLY IMPRESSIVE BUT AN ISOLATED
SEVERE STORM OR TWO CANNOT BE RULED OUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
DIURNAL CONVECTION WILL TAPER OFF EARLY THIS EVENING OVER LAND BUT
ISOLATED SHOWERS OR STORMS WILL REMAIN POSSIBLE OVER THE COASTAL
WATERS OVERNIGHT. SOME FOG IS POSSIBLE LATE TONIGHT...ESPECIALLY
IN AREAS WHERE RAIN OCCURS TODAY.
THURSDAY...ATLANTIC HIGH PRESSURE WILL PREVAIL WHILE WEAK TROUGHING
PERSISTS INLAND. A SHORTWAVE EMBEDDED WITHIN BROAD UPPER LEVEL
TROUGHING WILL CROSS THE REGION AND PUSH THE DEEP LAYERED MOISTURE
OFFSHORE AS THE DAY PROGRESSES. THERE IS THE POTENTIAL FOR ISOLATED
CONVECTION ACROSS THE AREA IN THE MORNING AHEAD OF THE SHORT
WAVE...WITH THE COVERAGE INCREASING TO SCATTERED IN THE AFTERNOON
ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA WHERE PRECIPITABLE WATER
VALUES AND LOW LEVEL CONVERGENCE WILL BE MAXIMIZED. A
WESTERLY/DOWNSLOPE FLOW ALOFT WILL PUSH TEMPERATURES TO HIGHS IN THE
UPPER 80S TO AROUND 90 AWAY FROM THE IMMEDIATE COAST.
THURSDAY NIGHT...AN UPPER LEVEL TROUGH WILL DIG TOWARD THE
APPALACHIANS...PUSHING A COLD FRONT ACROSS THE AREA. OTHER THAN SOME
ISOLATED CONVECTION EARLY IN THE EVENING MAINLY ACROSS THE
CHARLESTON TRI-COUNTY AREA...THE FRONT SHOULD PASS THROUGH RELATIVE
RAIN-FREE DUE TO A LACK OF DEEP LAYERED MOISTURE. LOWS WILL BE IN
THE LOWER TO MID 60S.
FRIDAY...THE UPPER LEVEL TROUGH WILL MOVE OVER THE MID-ATLANTIC AS
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE GREAT LAKES REGION
IN WAKE OF THE DEPARTING COLD FRONT. MUCH DRIER AIR WILL FILTER INTO
THE AREA WITH A STRONG NORTHWEST/DOWNSLOPE WIND COMPONENT. THERE
WILL BE CONSIDERABLE SUNSHINE ALONG WITH BREEZY CONDITIONS IN THE
AFTERNOON. THE DOWNSLOPE FLOW WILL NEGATE MUCH OF THE COLD AIR
ADVECTION...ALLOWING TEMPERATURES TO REACH HIGHS IN THE MID AND
UPPER 80S ACROSS THE AREA AWAY FROM THE IMMEDIATE COAST.
FRIDAY NIGHT...RADIATIONAL COOLING WILL BE LIMITED BY A COUPLED
NORTHERLY FLOW THROUGH MUCH OF THE NIGHT...BUT THE DRY AIRMASS AND
CLEAR SKIES SHOULD STILL ALLOW TEMPERATURES TO FALL INTO THE THE MID
AND UPPER 50S...WITH SOME LOWER 50S POSSIBLE WELL INLAND.
SATURDAY...AN EXTREMELY DRY AIRMASS WILL BE IN PLACE TO START THE
WEEKEND...WITH PRECIPITABLE WATER VALUES AS LOW AS .25 TO .50 INCHES
WHICH IS MORE THAN 2 STANDARD DEVIATIONS BELOW NORMAL FOR THIS TIME
OF YEAR. GIVEN THIS DRY AIRMASS...THERE WILL BE CONSIDERABLE
SUNSHINE BUT A NORTH-NORTHEAST FLOW WILL LIMIT HIGHS TO THE UPPER
70S TO LOWER 80S ACROSS SOUTHEAST SOUTH CAROLINA AND THE LOWER TO
MID 80S ACROSS SOUTHEAST GEORGIA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
ISOLATED CONVECTION IS EXPECTED TO DEVELOP IN THE VICINITY OF THE
TERMINALS LATE THIS MORNING ALONG THE SEA BREEZE...THEN SHIFT
INLAND OF THE TERMINALS LATER THIS AFTERNOON. COVERAGE/TIMING
UNCERTAINTIES PRECLUDE ANY MENTION IN THE TAF/S OTHER THAN
VICINITY SHOWERS THROUGH MID-AFTERNOON AT KCHS AND LATE AFTERNOON
AT KSAV. ABUNDANT LOW LEVEL MOISTURE COULD RESULT IN SOME REDUCED
CEILINGS/VISIBILITIES LATE TONIGHT.
EXTENDED AVIATION...ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH
THURSDAY. A COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT
WITH HIGH PRESSURE THEN BUILDING OVER THE REGION THROUGH EARLY
NEXT WEEK.
&&
.MARINE...
MARINE CONDITIONS LOOK PRETTY QUIET THROUGH TONIGHT AS THE AREA
REMAINS ON THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE. THE
SEABREEZE SHOULD DEVELOP LATE THIS MORNING BUT WIND SPEEDS AT THE
COAST ARE NOT EXPECTED TO BE TERRIBLY IMPRESSIVE.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL MOVE ACROSS THE AREA THURSDAY NIGHT WITH HIGH PRESSURE THEN
BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GAZ087-088-
099>101-114>116-137-138-140.
SC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR SCZ040-042.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JRL
SHORT TERM...JAQ
LONG TERM...JAQ
AVIATION...JAQ
MARINE...JRL/JAQ
TIDES/COASTAL FLOODING...
000
FXUS62 KFFC 221151
AFDFFC
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
745 AM EDT WED MAY 22 2013
.SHORT TERM /TODAY THROUGH THURSDAY/...
UPPER TROUGH WILL MOVE THROUGH THE UPPER MISSISSIPPI VALLEY TODAY
INTO TONIGHT. AN ASSOCIATED SHORT WAVE TRAILING INTO THE SOUTHERN
STATES WILL HELP FOCUS SHOWERS AND THUNDERSTORMS ACROSS THE CWA
THROUGH TONIGHT. AREA OF THUNDERSTORMS CURRENTLY MOVING INTO ALABAMA
MAY REACH NORTHWEST GEORGIA BY SUNRISE IF THEY HOLD TOGETHER. THIS
COMBINED WITH VARIOUS OUTFLOW BOUNDARIES WILL MAKE TIMING OF
CONVECTION DIFFICULT. HOWEVER THE BEST CHANCES WOULD SEEM TO BE THIS
AFTERNOON AND EVENING WITH DIURNAL HEATING. HAVE CONTINUED WITH THE
SEVERE WORDING ACROSS PORTIONS OF NORTH THIS AFTERNOON. THIS FITS
WELL WITH THE SPC SLIGHT RISK AREA. DIMINISHING POPS OVERNIGHT AS
THE SHORT WAVE MOVES INTO THE CAROLINAS. SOME DRYING INDICATED FOR
THURSDAY BUT WITH APPROACHING UPPER TROUGH...HAVE LEFT LOW POPS IN
ACROSS THE CWA. BASED ON TUESDAYS TEMPERATURES...HAVE STAYED ON THE
WARM SIDE OF MAV/MET. HOWEVER WITH ADDITIONAL CLOUDS AND
PRECIPITATION EXPECTED FOR TODAY...TEMPERATURES MAY VARY MORE ACROSS
THE CWA.
41
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A WEAK COLD FRONT AND MAIN UPPER SUPPORT WILL BE EXITING THE AREA
THURSDAY NIGHT. IT IS UNCLEAR HOW MUCH CONVECTIVE ACTIVITY THERE
WILL BE WITH THE GFS AND NAM INDICATING LITTLE OR NO MEASURABLE
RAIN AMOUNTS. LOOKS LIKE NO MORE THAN A SLIGHT CHANCE OF SHOWERS OR
THUNDERSTORMS FOR THE FIRST PART OF THURSDAY NIGHT.
MUCH DRIER AIRMASS MOVES OVER THE AREA ON FRIDAY WITH DRY NW FLOW
ALOFT AND SURFACE HIGH PRESSURE BUILDING OVER THE OH/TN VALLEYS
DURING THE DAY. GRADIENT WINDS WILL INCREASE GETTING CLOSE TO WIND
ADVISORY CRITERIA(20 MPH SUSTAINED) FOR SOME AREAS. DRY CONDITIONS
CONTINUE SATURDAY AND MOSTLY SUNDAY. HOWEVER THE NW FLOW ALOFT N OF
THE AREA IS BECOMING MORE ACTIVE WITH PRECIP CHANCES AND WHILE THE
GFS IS DRY FOR OUR AREA ON SUNDAY...MOISTURE IS SKIRTING NE GA. THE
EUROPEAN MEANWHILE IS INDICATING LIGHT PRECIP AMOUNTS OVER FAR N AND
E GA ON SUNDAY. A SIMILAR PATTERN CONTINUES FOR MONDAY AND TUESDAY
AS WELL. HIGH PRESSURE ALOFT BUILDS FOR WEDNESDAY AND EVEN WILL
SOUTHERLY FLOW OVER THE AREA...HIGH PRESSURE ALOFT WILL KEEP ANY
PRECIP CHANCES TO A MINIMUM. FOR NOW WILL FAVOR THE DRIER GFS.
TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH
THE PERIOD EXCEPT SATURDAY MORNING LOWS ARE RUNNING 10-15 DEGREES
BELOW NORMAL AND SUNDAY MORNING LOWS ARE RUNNING CLOSE TO 10
DEGREES BELOW NORMAL.
BDL
&&
.AVIATION...
12Z UPDATE...
EXPECTING VFR TODAY OUTSIDE OF AREAS OF SHOWERS/THUNDERSTORMS. THERE
MAY BE CONVECTION AROUND THE FORECAST AREA MUCH OF THE DAY BUT THE
BEST CHANCE FOR THUNDER AT ANY OF THE TAF SITES APPEARS TO BE 18Z
AND INTO THE EARLY EVENING UNTIL AROUND 02Z. VARIABLE TO LIGHT
SOUTHEAST WINDS THIS MORNING BECOMING SOUTHWEST 10KT AFTER 14Z.
VARIABLE TO GUSTY WINDS IN THUNDERSTORMS.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF CONVECTION.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 65 87 59 / 40 40 30 20
ATLANTA 86 66 85 60 / 50 40 30 20
BLAIRSVILLE 80 61 80 55 / 60 60 30 20
CARTERSVILLE 84 63 84 57 / 60 60 30 20
COLUMBUS 90 67 89 63 / 30 30 30 20
GAINESVILLE 85 65 83 57 / 50 50 30 20
MACON 90 65 89 61 / 30 30 30 10
ROME 84 63 85 57 / 60 60 30 20
PEACHTREE CITY 86 62 86 59 / 40 30 30 20
VIDALIA 88 67 89 67 / 30 30 30 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....BDL
AVIATION...41
000
FXUS62 KCAE 221046
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
646 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH LOW-LEVEL MOISTURE HAS HELPED CAUSE AREAS OF STRATUS AND FOG
EARLY THIS MORNING. DENSE FOG WAS OCCURRING IN PARTS OF THE AREA.
WE HAVE ISSUED A DENSE FOG ADVISORY FOR EARLY THIS MORNING.
DIURNAL HEATING SHOULD BEGIN TO DIMINISH ANY FOG BY 900 AM.
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE
MOIST AIR INTO THE FORECAST AREA TODAY. THE NAM AND GFS CONTINUE TO
INDICATE A WEAK MID-LEVEL SHORTWAVE TROUGH LINGERING OVER THE
FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS MAINLY DURING THE
TIME OF MAXIMUM HEATING. USED AN AVERAGE OF THE GFS AND NAM MOS
POPS. PRECIPITABLE WATER NEAR 1.7 OF AN INCH AND SLOW STORM
MOVEMENT SUPPORTS HEAVY RAIN WILL SOME OF THE THUNDERSTORMS. HEAVY
PRECIPITATION LOADINGS AND POSSIBLY MODERATE INSTABILITY WITH H5
TEMPERATURES AROUND -10 SUPPORT A POSSIBILITY OF DAMAGING WIND.
USED THE WARMER TEMPERATURE GUIDANCE FOR TODAY BASED ON
YESTERDAY/S VERIFICATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
A CONTINUED MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH
PLUS A PRE-FRONTAL TROUGH SUPPORT THUNDERSTORMS TONIGHT. COVERAGE
WILL LIKELY BE LIMITED BY DIURNAL COOLING AND PREVIOUS CONVECTION.
THE NAM AND GFS MOS ARE IN GOOD AGREEMENT WITH POPS 30 TO 40 PERCENT.
THE MODELS SHOW THE PRE-FRONTAL TROUGH LINGERING THURSDAY BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE FORECAST AREA EARLY
AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE NAM AND GFS MOS
INDICATE VERY LOW POPS...BUT MAINTAINED CHANCE POPS BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE PRE-FRONTAL TROUGH THURSDAY AND
THE COLD FRONT THURSDAY EVENING. FURTHER DRYING SHOULD OCCUR
BEHIND THE FRONT BY LATE THURSDAY NIGHT. THE TEMPERATURE GUIDANCE
WAS CLOSE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
AND TUESDAY. THE GFS AND ECMWF MOS PLUS GFS ENSEMBLE MEAN SUPPORTS
VERY LOW POPS. EXPECT BELOW NORMAL TEMPERATURES DURING THE
WEEKEND AND NEAR NORMAL DURING THE REST OF THE MEDIUM RANGE
PERIOD.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
EXPECT PERIODS OF MVFR/IFR AT MOST OF THE TAF SITES UNTIL AROUND
13Z...WITH POSSIBLE LIFR AT AGS. STRATUS AND FOG EXPECTED TO BURN
OFF DURING THE EARLY TO MID MORNING. LOW LEVEL MOISTURE WILL
REMAIN HIGH. VFR CONDITIONS DURING THE LATE MORNING AND AFTERNOON
WITH SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z. GIVEN THE
EXPECTED SCATTERED NATURE OF THE CONVECTION...NOT ENOUGH
CONFIDENCE TO MENTION THUNDER IN THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
GA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GAZ040-
063>065-077.
&&
$$
000
FXUS62 KCAE 221009
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
609 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH LOW-LEVEL MOISTURE AND LIGHT WIND HAS HELPED CAUSE AREAS OF
FOG EARLY THIS MORNING. DENSE FOG WAS REPORTED AT AUGUSTA AND
ORANGEBURG. WE HAVE ISSUED A DENSE FOG ADVISORY FOR THE SOUTH PART
FOR EARLY THIS MORNING. DIURNAL HEATING SHOULD BEGIN TO DIMINISH
THE FOG BY 900 AM.
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE
MOIST AIR INTO THE FORECAST AREA TODAY. THE NAM AND GFS CONTINUE TO
INDICATE A WEAK MID-LEVEL SHORTWAVE TROUGH LINGERING OVER THE
FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS MAINLY DURING THE
TIME OF MAXIMUM HEATING. USED AN AVERAGE OF THE GFS AND NAM MOS
POPS. PRECIPITABLE WATER NEAR 1.7 OF AN INCH AND SLOW STORM
MOVEMENT SUPPORTS HEAVY RAIN WILL SOME OF THE THUNDERSTORMS. HEAVY
PRECIPITATION LOADINGS AND POSSIBLY MODERATE INSTABILITY WITH H5
TEMPERATURES AROUND -10 SUPPORT A POSSIBILITY OF DAMAGING WIND.
USED THE WARMER TEMPERATURE GUIDANCE FOR TODAY BASED ON
YESTERDAY/S VERIFICATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
A CONTINUED MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH
PLUS A PRE-FRONTAL TROUGH SUPPORT THUNDERSTORMS TONIGHT. COVERAGE
WILL LIKELY BE LIMITED BY DIURNAL COOLING AND PREVIOUS CONVECTION.
THE NAM AND GFS MOS ARE IN GOOD AGREEMENT WITH POPS 30 TO 40 PERCENT.
THE MODELS SHOW THE PRE-FRONTAL TROUGH LINGERING THURSDAY BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE FORECAST AREA EARLY
AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE NAM AND GFS MOS
INDICATE VERY LOW POPS...BUT MAINTAINED CHANCE POPS BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE PRE-FRONTAL TROUGH THURSDAY AND
THE COLD FRONT THURSDAY EVENING. FURTHER DRYING SHOULD OCCUR
BEHIND THE FRONT BY LATE THURSDAY NIGHT. THE TEMPERATURE GUIDANCE
WAS CLOSE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
AND TUESDAY. THE GFS AND ECMWF MOS PLUS GFS ENSEMBLE MEAN SUPPORTS
VERY LOW POPS. EXPECT BELOW NORMAL TEMPERATURES DURING THE
WEEKEND AND NEAR NORMAL DURING THE REST OF THE MEDIUM RANGE
PERIOD.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
EXPECT PERIODS OF MVFR/IFR AT MOST OF THE TAF SITES UNTIL AROUND
13Z...WITH POSSIBLE LIFR AT AGS. STRATUS AND FOG EXPECTED TO BURN
OFF DURING THE EARLY TO MID MORNING. LOW LEVEL MOISTURE WILL
REMAIN HIGH. VFR CONDITIONS DURING THE LATE MORNING AND AFTERNOON
WITH SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z. GIVEN THE
EXPECTED SCATTERED NATURE OF THE CONVECTION...NOT ENOUGH
CONFIDENCE TO MENTION THUNDER IN THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR SCZ030-
035>038-041.
GA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GAZ063>065-
077.
&&
$$
000
FXUS62 KCAE 220914
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
514 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH LOW-LEVEL MOISTURE AND LIGHT WIND HAS HELPED CAUSE AREAS OF
FOG EARLY THIS MORNING. DENSE FOG WAS REPORTED AT AUGUSTA AND
ORANGEBURG. WE HAVE ISSUED A DENSE FOG ADVISORY FOR THE SOUTH PART
FOR EARLY THIS MORNING. DIURNAL HEATING SHOULD BEGIN TO DIMINISH
THE FOG BY 900 AM.
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO CIRCULATE
MOIST AIR INTO THE FORECAST AREA TODAY. THE NAM AND GFS CONTINUE TO
INDICATE A WEAK MID-LEVEL SHORTWAVE TROUGH LINGERING OVER THE
FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS MAINLY DURING THE
TIME OF MAXIMUM HEATING. USED AN AVERAGE OF THE GFS AND NAM MOS
POPS. PRECIPITABLE WATER NEAR 1.7 OF AN INCH AND SLOW STORM
MOVEMENT SUPPORTS HEAVY RAIN WILL SOME OF THE THUNDERSTORMS. HEAVY
PRECIPITATION LOADINGS AND POSSIBLY MODERATE INSTABILITY WITH H5
TEMPERATURES AROUND -10 SUPPORT A POSSIBILITY OF DAMAGING WIND.
USED THE WARMER TEMPERATURE GUIDANCE FOR TODAY BASED ON
YESTERDAY/S VERIFICATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
A CONTINUED MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH
PLUS A PRE-FRONTAL TROUGH SUPPORT THUNDERSTORMS TONIGHT. COVERAGE
WILL LIKELY BE LIMITED BY DIURNAL COOLING AND PREVIOUS CONVECTION.
THE NAM AND GFS MOS ARE IN GOOD AGREEMENT WITH POPS 30 TO 40 PERCENT.
THE MODELS SHOW THE PRE-FRONTAL TROUGH LINGERING THURSDAY BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE FORECAST AREA EARLY
AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE NAM AND GFS MOS
INDICATE VERY LOW POPS...BUT MAINTAINED CHANCE POPS BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE PRE-FRONTAL TROUGH THURSDAY AND
THE COLD FRONT THURSDAY EVENING. FURTHER DRYING SHOULD OCCUR
BEHIND THE FRONT BY LATE THURSDAY NIGHT. THE TEMPERATURE GUIDANCE
WAS CLOSE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
AND TUESDAY. THE GFS AND ECMWF MOS PLUS GFS ENSEMBLE MEAN SUPPORTS
VERY LOW POPS. EXPECT BELOW NORMAL TEMPERATURES DURING THE
WEEKEND AND NEAR NORMAL DURING THE REST OF THE MEDIUM RANGE
PERIOD.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
EXPECT SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS SHOULD DIMINISH
DURING THE EARLY MORNING HOURS. WITH CLEARING SKIES EXPECT AREAS OF
FOG AND STRATUS TO DEVELOP WHERE MOST OF THE RAIN FELL YESTERDAY.
EXPECT PERIODS OF MVFR/IFR AT MOST OF THE TAF SITES UNTIL AROUND
13Z...WITH POSSIBLE LIFR AT AGS. STRATUS AND FOG EXPECTED TO BURN
OFF DURING THE EARLY TO MID MORNING. LOW LEVEL MOISTURE WILL REMAIN
HIGH. VFR CONDITIONS DURING THE LATE MORNING AND AFTERNOON WITH
SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z. GIVEN THE EXPECTED
SCATTERED NATURE OF THE CONVECTION...NOT ENOUGH CONFIDENCE TO
MENTION THUNDER IN THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR SCZ030-
035>038-041.
GA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR GAZ063>065-
077.
&&
$$
000
FXUS62 KCHS 220835
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
435 AM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL MOVE ACROSS THE AREA THURSDAY NIGHT WITH HIGH PRESSURE THEN
BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK SHORTWAVE TROUGHING AT UPPER LEVELS TO PERSIST TODAY WHILE
ATLANTIC HIGH PRESSURE EXTENDS WEST INTO THE SOUTHEAST STATES AT
THE SURFACE. THE IN-SITU AIRMASS REMAINS QUITE MOIST WITH PW
VALUES HOVERING AT OR ABOVE 1.60 INCHES. THROUGH DAYBREAK A FEW
SHOWERS ARE POSSIBLE OVER THE COASTAL WATERS AND IMMEDIATE SC
COAST MAINLY NORTHEAST OF CHARLESTON IN SOME WEAK MOISTURE
CONVERGENCE. AFTER SUNRISE...THE DEEP-LAYERED SOUTHEAST FLOW WILL
ALLOW THE SEABREEZE TO DEVELOP FAIRLY EARLY. WITH TEMPS PUSHING
INTO THE MIDDLE TO UPPER 80S...MODERATE INSTABILITY WILL DEVELOP
YET AGAIN. SHOWERS AND TSTMS WILL INCREASE IN COVERAGE FROM LATE
MORNING INTO THE AFTERNOON WITH THE ACTIVITY LIKELY SHIFTING
GRADUALLY INLAND. CONVECTIVE PARAMETERS ARE NOT TERRIBLY
IMPRESSIVE BUT AN ISOLATED SEVERE STORM OR TWO CANNOT BE RULED
OUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
DIURNAL CONVECTION WILL TAPER OFF EARLY THIS EVENING OVER LAND BUT
ISOLATED SHOWERS OR STORMS WILL REMAIN POSSIBLE OVER THE COASTAL
WATERS OVERNIGHT. SOME FOG IS POSSIBLE LATE TONIGHT...ESPECIALLY
IN AREAS WHERE RAIN OCCURS TODAY.
THURSDAY...ATLANTIC HIGH PRESSURE WILL PREVAIL WHILE WEAK TROUGHING
PERSISTS INLAND. A SHORTWAVE EMBEDDED WITHIN BROAD UPPER LEVEL
TROUGHING WILL CROSS THE REGION AND PUSH THE DEEP LAYERED MOISTURE
OFFSHORE AS THE DAY PROGRESSES. THERE IS THE POTENTIAL FOR ISOLATED
CONVECTION ACROSS THE AREA IN THE MORNING AHEAD OF THE SHORT
WAVE...WITH THE COVERAGE INCREASING TO SCATTERED IN THE AFTERNOON
ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA WHERE PRECIPITABLE WATER
VALUES AND LOW LEVEL CONVERGENCE WILL BE MAXIMIZED. A
WESTERLY/DOWNSLOPE FLOW ALOFT WILL PUSH TEMPERATURES TO HIGHS IN THE
UPPER 80S TO AROUND 90 AWAY FROM THE IMMEDIATE COAST.
THURSDAY NIGHT...AN UPPER LEVEL TROUGH WILL DIG TOWARD THE
APPALACHIANS...PUSHING A COLD FRONT ACROSS THE AREA. OTHER THAN SOME
ISOLATED CONVECTION EARLY IN THE EVENING MAINLY ACROSS THE
CHARLESTON TRI-COUNTY AREA...THE FRONT SHOULD PASS THROUGH RELATIVE
RAIN-FREE DUE TO A LACK OF DEEP LAYERED MOISTURE. LOWS WILL BE IN
THE LOWER TO MID 60S.
FRIDAY...THE UPPER LEVEL TROUGH WILL MOVE OVER THE MID-ATLANTIC AS
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE GREAT LAKES REGION
IN WAKE OF THE DEPARTING COLD FRONT. MUCH DRIER AIR WILL FILTER INTO
THE AREA WITH A STRONG NORTHWEST/DOWNSLOPE WIND COMPONENT. THERE
WILL BE CONSIDERABLE SUNSHINE ALONG WITH BREEZY CONDITIONS IN THE
AFTERNOON. THE DOWNSLOPE FLOW WILL NEGATE MUCH OF THE COLD AIR
ADVECTION...ALLOWING TEMPERATURES TO REACH HIGHS IN THE MID AND
UPPER 80S ACROSS THE AREA AWAY FROM THE IMMEDIATE COAST.
FRIDAY NIGHT...RADIATIONAL COOLING WILL BE LIMITED BY A COUPLED
NORTHERLY FLOW THROUGH MUCH OF THE NIGHT...BUT THE DRY AIRMASS AND
CLEAR SKIES SHOULD STILL ALLOW TEMPERATURES TO FALL INTO THE THE MID
AND UPPER 50S...WITH SOME LOWER 50S POSSIBLE WELL INLAND.
SATURDAY...AN EXTREMELY DRY AIRMASS WILL BE IN PLACE TO START THE
WEEKEND...WITH PRECIPITABLE WATER VALUES AS LOW AS .25 TO .50 INCHES
WHICH IS MORE THAN 2 STANDARD DEVIATIONS BELOW NORMAL FOR THIS TIME
OF YEAR. GIVEN THIS DRY AIRMASS...THERE WILL BE CONSIDERABLE
SUNSHINE BUT A NORTH-NORTHEAST FLOW WILL LIMIT HIGHS TO THE UPPER
70S TO LOWER 80S ACROSS SOUTHEAST SOUTH CAROLINA AND THE LOWER TO
MID 80S ACROSS SOUTHEAST GEORGIA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
BETTER CHANCES FOR VSBY/CEILING RESTRICTIONS AT BOTH TERMINALS DUE
TO SUBSTANTIAL RAINFALL ON TUESDAY. KSAV WILL LIKELY CONTINUE AT
LEAST MVFR CEILINGS WITH POSSIBLE BRIEF DROPS TO IFR BEFORE
DAYBREAK. WE STILL SHOW KCHS DROPPING TO MVFR CIG/VSBY PRIOR TO
DAYBREAK AS WELL. THE BEST CHANCE OF DENSE FOG OR THE LIKE WILL BE
INLAND FROM EITHER TERMINAL.
FOR THE REST OF TODAY THE MAIN ISSUE IS ANOTHER ROUND OF CONVECTION
DEVELOPING ALONG THE SEABREEZE. WE INCLUDED PROB30 SHRA AT BOTH
TERMINALS FOR THE AFTERNOON HOURS GIVEN PRETTY GOOD INDICATIONS
THAT A LINE OF SHOWERS/STORMS WILL ROLL THROUGH THE AIRPORTS.
EXTENDED AVIATION...ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH
THURSDAY. A COLD FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT
WITH HIGH PRESSURE THEN BUILDING OVER THE REGION THROUGH EARLY
NEXT WEEK.
&&
.MARINE...
MARINE CONDITIONS LOOK PRETTY QUIET THROUGH TONIGHT AS THE AREA
REMAINS ON THE WESTERN PERIPHERY OF ATLANTIC HIGH PRESSURE. THE
SEABREEZE SHOULD DEVELOP LATE THIS MORNING BUT WIND SPEEDS AT THE
COAST ARE NOT EXPECTED TO BE TERRIBLY IMPRESSIVE.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL MOVE ACROSS THE AREA THURSDAY NIGHT WITH HIGH PRESSURE THEN
BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JRL
SHORT TERM...JAQ
LONG TERM...JAQ
AVIATION...JAQ/JRL
MARINE...JAQ/JRL
TIDES/COASTAL FLOODING...JAQ
000
FXUS62 KFFC 220800
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
400 AM EDT WED MAY 22 2013
.SHORT TERM /TODAY THROUGH THURSDAY/...
UPPER TROUGH WILL MOVE THROUGH THE UPPER MISSISSIPPI VALLEY TODAY
INTO TONIGHT. AN ASSOCIATED SHORT WAVE TRAILING INTO THE SOUTHERN
STATES WILL HELP FOCUS SHOWERS AND THUNDERSTORMS ACROSS THE CWA
THROUGH TONIGHT. AREA OF THUNDERSTORMS CURRENTLY MOVING INTO ALABAMA
MAY REACH NORTHWEST GEORGIA BY SUNRISE IF THEY HOLD TOGETHER. THIS
COMBINED WITH VARIOUS OUTFLOW BOUNDARIES WILL MAKE TIMING OF
CONVECTION DIFFICULT. HOWEVER THE BEST CHANCES WOULD SEEM TO BE THIS
AFTERNOON AND EVENING WITH DIURNAL HEATING. HAVE CONTINUED WITH THE
SEVERE WORDING ACROSS PORTIONS OF NORTH THIS AFTERNOON. THIS FITS
WELL WITH THE SPC SLIGHT RISK AREA. DIMINISHING POPS OVERNIGHT AS
THE SHORT WAVE MOVES INTO THE CAROLINAS. SOME DRYING INDICATED FOR
THURSDAY BUT WITH APPROACHING UPPER TROUGH...HAVE LEFT LOW POPS IN
ACROSS THE CWA. BASED ON TUESDAYS TEMPERATURES...HAVE STAYED ON THE
WARM SIDE OF MAV/MET. HOWEVER WITH ADDITIONAL CLOUDS AND
PRECIPITATION EXPECTED FOR TODAY...TEMPERATURES MAY VARY MORE ACROSS
THE CWA.
41
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A WEAK COLD FRONT AND MAIN UPPER SUPPORT WILL BE EXITING THE AREA
THURSDAY NIGHT. IT IS UNCLEAR HOW MUCH CONVECTIVE ACTIVITY THERE
WILL BE WITH THE GFS AND NAM INDICATING LITTLE OR NO MEASURABLE
RAIN AMOUNTS. LOOKS LIKE NO MORE THAN A SLIGHT CHANCE OF SHOWERS OR
THUNDERSTORMS FOR THE FIRST PART OF THURSDAY NIGHT.
MUCH DRIER AIRMASS MOVES OVER THE AREA ON FRIDAY WITH DRY NW FLOW
ALOFT AND SURFACE HIGH PRESSURE BUILDING OVER THE OH/TN VALLEYS
DURING THE DAY. GRADIENT WINDS WILL INCREASE GETTING CLOSE TO WIND
ADVISORY CRITERIA(20 MPH SUSTAINED) FOR SOME AREAS. DRY CONDITIONS
CONTINUE SATURDAY AND MOSTLY SUNDAY. HOWEVER THE NW FLOW ALOFT N OF
THE AREA IS BECOMING MORE ACTIVE WITH PRECIP CHANCES AND WHILE THE
GFS IS DRY FOR OUR AREA ON SUNDAY...MOISTURE IS SKIRTING NE GA. THE
EUROPEAN MEANWHILE IS INDICATING LIGHT PRECIP AMOUNTS OVER FAR N AND
E GA ON SUNDAY. A SIMILAR PATTERN CONTINUES FOR MONDAY AND TUESDAY
AS WELL. HIGH PRESSURE ALOFT BUILDS FOR WEDNESDAY AND EVEN WILL
SOUTHERLY FLOW OVER THE AREA...HIGH PRESSURE ALOFT WILL KEEP ANY
PRECIP CHANCES TO A MINIMUM. FOR NOW WILL FAVOR THE DRIER GFS.
TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH
THE PERIOD EXCEPT SATURDAY MORNING LOWS ARE RUNNING 10-15 DEGREES
BELOW NORMAL AND SUNDAY MORNING LOWS ARE RUNNING CLOSE TO 10
DEGREES BELOW NORMAL.
BDL
&&
.AVIATION...
06Z UPDATE...
SOME MID/HIGH CLOUDS LINGERING INTO THE MORNING HOURS. VISIBILITY
SHOULD REMAIN ABOVE 6SM...BUT MAY DROP TO MVFR MAINLY ATHENS AND
MACON. VFR DURING THE DAY TODAY EXCEPT IN SHOWERS AND THUNDERSTORMS.
THERE MAY BE CONVECTION AROUND THE FORECAST AREA MUCH OF THE DAY BUT
THE BEST CHANCE FOR THUNDER AT ANY OF THE TAF SITES APPEARS TO BE
18Z AND INTO THE EARLY EVENING. VARIABLE TO LIGHT SOUTHEAST WINDS
THIS MORNING BECOMING SOUTHWEST 10KT AFTER 14Z.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF CONVECTION.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 65 87 59 / 40 40 30 20
ATLANTA 86 66 85 60 / 50 40 30 20
BLAIRSVILLE 80 61 80 55 / 60 60 30 20
CARTERSVILLE 84 63 84 57 / 60 60 30 20
COLUMBUS 90 67 89 63 / 30 30 30 20
GAINESVILLE 85 65 83 57 / 50 50 30 20
MACON 90 65 89 61 / 30 30 30 10
ROME 84 63 85 57 / 60 60 30 20
PEACHTREE CITY 86 62 86 59 / 40 30 30 20
VIDALIA 88 67 89 67 / 30 30 30 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....BDL
AVIATION...41
000
FXUS62 KCAE 220720
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
320 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REST OF TONIGHT...CONTINUED HIGH LOW-LEVEL MOISTURE SHOULD SUPPORT
STRATUS AND AREAS OF FOG DURING THE EARLY MORNING HOURS. THE
CLOUDINESS SHOULD HELP HOLD UP TEMPERATURES. THE TEMPERATURE
FORECAST APPEARS ON TRACK WITH LOWS IN THE MIDDLE 60S.
TODAY...HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO
CIRCULATE MOIST AIR INTO THE FORECAST AREA. THE NAM AND GFS
CONTINUE TO INDICATE A WEAK MID-LEVEL SHORTWAVE TROUGH LINGERING
OVER THE FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS MAINLY
DURING THE TIME OF MAXIMUM HEATING. USED AN AVERAGE OF THE GFS AND
NAM MOS POPS. PRECIPITABLE WATER NEAR 1.7 OF AN INCH AND SLOW
STORM MOVEMENT SUPPORTS HEAVY RAIN WILL SOME OF THE THUNDERSTORMS.
HEAVY PRECIPITATION LOADINGS AND POSSIBLY MODERATE INSTABILITY
WITH H5 TEMPERATURES AROUND -10 SUPPORT A POSSIBILITY OF DAMAGING
WIND. USED THE WARMER TEMPERATURE GUIDANCE FOR TODAY BASED ON
YESTERDAY/S VERIFICATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
A CONTINUED MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH
PLUS A PRE-FRONTAL TROUGH SUPPORT THUNDERSTORMS TONIGHT. COVERAGE
WILL LIKELY BE LIMITED BY DIURNAL COOLING AND PREVIOUS CONVECTION.
THE NAM AND GFS MOS ARE IN GOOD AGREEMENT WITH POPS 30 TO 40 PERCENT.
THE MODELS SHOW THE PRE-FRONTAL TROUGH LINGERING THURSDAY BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE FORECAST AREA EARLY
AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE NAM AND GFS MOS
INDICATE VERY LOW POPS...BUT MAINTAINED CHANCE POPS BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE PRE-FRONTAL TROUGH THURSDAY AND
THE COLD FRONT THURSDAY EVENING. FURTHER DRYING SHOULD OCCUR
BEHIND THE FRONT BY LATE THURSDAY NIGHT. THE TEMPERATURE GUIDANCE
WAS CLOSE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
AND TUESDAY. THE GFS AND ECMWF MOS PLUS GFS ENSEMBLE MEAN SUPPORTS
VERY LOW POPS. EXPECT BELOW NORMAL TEMPERATURES DURING THE
WEEKEND AND NEAR NORMAL DURING THE REST OF THE MEDIUM RANGE
PERIOD.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
EXPECT SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS SHOULD DIMINISH
DURING THE EARLY MORNING HOURS. WITH CLEARING SKIES EXPECT AREAS OF
FOG AND STRATUS TO DEVELOP WHERE MOST OF THE RAIN FELL YESTERDAY.
EXPECT PERIODS OF MVFR/IFR AT MOST OF THE TAF SITES UNTIL AROUND
13Z...WITH POSSIBLE LIFR AT AGS. STRATUS AND FOG EXPECTED TO BURN
OFF DURING THE EARLY TO MID MORNING. LOW LEVEL MOISTURE WILL REMAIN
HIGH. VFR CONDITIONS DURING THE LATE MORNING AND AFTERNOON WITH
SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z. GIVEN THE EXPECTED
SCATTERED NATURE OF THE CONVECTION...NOT ENOUGH CONFIDENCE TO
MENTION THUNDER IN THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
000
FXUS62 KCHS 220614
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
214 AM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A
COLD FRONT WILL MOVE THROUGH THE AREA ON FRIDAY WITH DRY HIGH
PRESSURE BUILDING IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE FORECAST AREA LIES UNDERNEATH A WELL-DEFINED MID LEVEL
IMPULSE ACROSS FLORIDA WITH STRUNG OUT VORTICITY STRETCHING NORTH
AND NE OVERHEAD TO OFF THE COAST OF NC AND SE VA. THIS FEATURE
WILL MOVE LITTLE THROUGH THE NIGHT. MEANWHILE...THE BERMUDA HIGH
WILL LIE ATOP THE REGION AS A SUBTLE TROUGH DEVELOPS OVER THE
NEARBY ATLANTIC LATE.
MUCH OF THE NIGHT WILL BE RAIN FREE...ALTHOUGH WITH THE SHORT WAVE
ALOFT AND SOME CONVERGENCE DOWNSTAIRS...GIVEN THAT PWATS ARE NEAR
2 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE MAY...WE LOOK FOR AN
INCREASE IN CONVECTION AGAIN OVER THE ATLANTIC OVERNIGHT. WE/RE
ALREADY SEEING SIGNS OF THAT OUT NEAR THE GULF STREAM. WITHIN THE
SOUTHERLY SYNOPTIC FLOW WE ANTICIPATE SOME OF THIS ACTIVITY WILL
MOVE INTO CHARLESTON AND FAR SE BERKELEY COUNTY BY SUNRISE.
GIVEN THE COPIOUS AMOUNT OF RAINS FROM EARLIER TODAY...FOG WILL
BECOME PROBLEMATIC AGAIN OVERNIGHT AS THE MID/HIGH LEVEL
CONVECTIVE DEBRIS CLOUD COVER DIMINISHES. WE HAVE EXPANDED THE
PATCHY FOG A LITTLE FURTHER SE WITH THE LATE EVENING UPDATE...AND
INCLUDED AREAS OF FOG ALONG PARTS OF THE NW TIER WHERE SOME OF THE
BETTER RAINFALL OCCURRED. LOCALLY DENSE FOG IS CERTAINLY A CONCERN
AND WE WILL RE-EVALUATE AGAIN WITH FUTURE UPDATES.
CONDITIONS WILL BE STICKY AND BALMY TONIGHT...WITH MINIMUM TEMPS
NO LOWER THAN THE MID-UPPER 60S INLAND AND AROUND 70 NEAR THE SHORE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY AND THURSDAY WITH
BROAD UPPER TROUGHING INLAND AND HIGH PRESSURE OVER THE ATLANTIC.
THIS PATTERN WILL MAINTAIN DEEP MOISTURE OVER THE AREA WITH DECENT
RAIN CHANCES THROUGH THE PERIOD...MOSTLY CONFINED INLAND DURING THE
DAY AND OVER THE ATLANTIC AT NIGHT. THE RISK FOR SEVERE WEATHER
APPEARS LOW GIVEN THE LACK OF ORGANIZATION POTENTIAL...ALTHOUGH
HEAVY RAINFALL COULD RESULT IN LOCALIZED FLOODING. HIGH/LOW
TEMPERATURES WILL ULTIMATELY DEPEND ON CLOUD COVER/RAINFALL BUT
GENERALLY SHOULD BE CLOSE TO SLIGHTLY ABOVE NORMAL.
A COLD FRONT SHOULD PUSH THROUGH FRIDAY MORNING...ALTHOUGH THE
NORTHWEST DOWNSLOPE FLOW WILL HELP TO OFFSET THE COLD ADVECTION.
THIS SHOULD LEAD TO TEMPERATURES CLOSE TO NORMAL IN THE MID 80S. THE
BIGGER CHANGE WILL BE THE DRIER AIR WHICH WILL MAKE IT FEEL A LOT
MORE COMFORTABLE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
BETTER CHANCES FOR VSBY/CEILING RESTRICTIONS AT BOTH TERMINALS DUE
TO SUBSTANTIAL RAINFALL ON TUESDAY. KSAV WILL LIKELY CONTINUE AT
LEAST MVFR CEILINGS WITH POSSIBLE BRIEF DROPS TO IFR BEFORE
DAYBREAK. WE STILL SHOW KCHS DROPPING TO MVFR CIG/VSBY PRIOR TO
DAYBREAK AS WELL. THE BEST CHANCE OF DENSE FOG OR THE LIKE WILL BE
INLAND FROM EITHER TERMINAL.
FOR THE REST OF TODAY THE MAIN ISSUE IS ANOTHER ROUND OF CONVECTION
DEVELOPING ALONG THE SEABREEZE. WE INCLUDED PROB30 SHRA AT BOTH
TERMINALS FOR THE AFTERNOON HOURS GIVEN PRETTY GOOD INDICATIONS
THAT A LINE OF SHOWERS/STORMS WILL ROLL THROUGH THE AIRPORTS.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
TONIGHT...THE TYPICAL SUB-TROPICAL RIDGE OF HIGH PRESSURE WILL
CONTINUE TO STRETCH ACROSS THE COASTAL WATERS...GENERATING SE AND
SOUTH WINDS OF LESS THAN 10 OR 15 KT. SEAS WILL HOLD IN A FAIRLY
STEADY STATE AT 2-4 FT...MAINLY IN A SE SWELL. WHILE THE RISK IS NOT
PARTICULARLY HIGH...THERE IS NONETHELESS A CHANCE OF ISOLATED
STRONGER STORMS MOVING IN AFTER 06Z.
WEDNESDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES THROUGH FRIDAY. THE
MUCH COOLER AND DRIER AIR MASS BEHIND THE FRONT WILL MOVE IN AND
LEAD TO INCREASING WINDS AND BUILDING SEAS...POSSIBLY REACHING
ADVISORY LEVELS...AT LEAST ACROSS THE WATERS BEYOND 20 NM.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AS WELL AS MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE BUT MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JRL
SHORT TERM...RJB
LONG TERM...JRL
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KFFC 220540
AFDFFC
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
135 AM EDT WED MAY 22 2013
.UPDATE...
UPDATED TO INCLUDE SOME POPS THROUGH MIDNIGHT FOR WEST CENTRAL GA AS
WESTWARD MOVING OUTFLOW BOUNDARY LIKELY TO SPAWN A FEW MORE
THUNDERSTORMS. WATCHING CLOSELY STORMS ACROSS NORTH GA FOR
POSSIBLE LOCALIZED FF THREAT AS WELL. MOST STORMS HAVE BEEN
PRODUCING PEA TO NICKEL SIZED HAIL THIS EVE AND EXPECT TREND TO
CONTINUE THROUGH 4Z TO 5Z.
OTHER UPDATE WAS TO GRIDS WED AFTN AND EVE TO INCLUDE SMALL HAIL
AND GUSTY WINDS AS THERE APPEARS TO BE A MARGINAL SEVERE THREAT
DUE TO SLIGHTLY INCREASING DEEP LAYER SHEAR
PROFILES....PARTICULARLY ACROSS NW AND NE GA. WILL NEED TO MONITOR
FOR POTENTIALLY INCREASING SEVERE THREAT AFTER 3 PM WED.
&&
.PREV DISCUSSION... /ISSUED 805 PM EDT TUE MAY 21 2013/
PREV DISCUSSION... /ISSUED 314 PM EDT TUE MAY 21 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE IN GOOD AGREEMENT THROUGH THE SHORT TERM. AIRMASS
SHOWERS/TSTORMS DEVELOPING ACROSS THE CWA...MAINLY ACROSS THE
EXTREME NORTH AND EASTERN PARTS OF THE CWA. THESE WILL DISSIPATE
SHORTLY AFTER SUNSET THIS EVENING. THERE IS A POSSIBILITY THAT THE
STORMS OVER NORTHWEST AL AND CENTRAL TN COULD MAKE IT TO EXTREME
NORTHWEST GA BEFORE DIMINISHING THIS EVENING. THE H5 RIDGE OVER THE
EASTERN U.S. WILL WEAKEN AS THE CENTRAL U.S. TROUGH MOVES INTO THE
MISSISSIPPI VALLEY. THIS WILL PUSH A COLD FRONT INTO THE TENNESSEE
VALLEY WEDNESDAY WHICH WILL BRING A BETTER CHANCE OF THUNDERSTORMS
TO THE CWA...MAINLY ACROSS NORTH GA. INSTABILITY INCREASES WEDNESDAY
ACROSS NORTH GA AND THIS COULD PRODUCE A FEW STRONG STORMS. GUIDANCE
TEMPS LOOK GOOD FOR TONIGHT...ALTHOUGH TRICKY FOR WEDNESDAY WITH
ADDITIONAL CLOUDS. WILL TREND TO THE COOLER SIDE OF GUIDANCE ACROSS
NORTH GA FOR HIGHS ON WEDNESDAY DUE TO INCREASED CLOUDS AND PRECIP.
17
LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
BY WEDNESDAY EVENING...BOTH THE GFS AND ECMWF INDICATE THAT THE
FRONT WILL BE WEAKENING SIGNIFICANTLY. GFS REMAINS AB IT ON THE
STRONG SIDE WITH A SLIGHTLY MORE EAST WITH THE GREAT LAKES SURFACE
LOW. BOTH ARE TRANSITIONING THE UPPER LOW TO MORE OF A SHARP OPEN
TROUGH PHASING WITH THE LONGWAVE TROUGH IN CANADA. WEAK SHORTWAVE
OFF THE SOUTH CAROLINA COAST WILL LIFT NORTHEAST AND BE ABSORBED
BY THE LONGWAVE TROUGH AS WELL. SPC CONTINUES THE AREA IN GENERAL
THUNDER FOR THURSDAY...WITH MUCAPE VALUES 500-1000 J/KG EARLY IN
THE DAY...DECREASING BY MID-MORNING...AND INCREASING AGAIN IN
EXTREME SOUTHERN ZONES JUST AHEAD OF THE FRONT AFTER 18Z TO OVER
1000 J/KG. WILL HAVE TO MONITOR THE AREA FOR THE POTENTIAL FOR
ISOLATED STRONG STORMS BUT NOTHING TO SIGNIFICANT.
COLD FRONT SHOULD BE PUSHED THROUGH THE AREA BY LATE THURSDAY...
AND HAVE DECREASED TEMPS NORTHWEST SOMEWHAT TO LINE UP WITH THAT
TIMING A LITTLE BETTER. SHOULD SEE A SIGNIFICANT DECREASE IN TEMPS
TOWARD THE END OF THE WEEK WITH SURFACE HIGH PRESSURE BUILDING IN
AND NORTHWEST FLOW ALOFT...CURRENT FORECAST HAS HIGHS ON FRIDAY
ABOUT 5 DEGREES COOLER THAN HIGHS ON THURSDAY EXCEPT IN CENTRAL
GEORGIA. SEE PREVIOUS LONG TERM DISCUSSION BELOW.
TDP
AVIATION...
06Z UPDATE...
SOME MID/HIGH CLOUDS LINGERING INTO THE MORNING HOURS. VISIBILITY
SHOULD REMAIN ABOVE 6SM...BUT MAY DROP TO MVFR MAINLY ATHENS AND
MACON. VFR DURING THE DAY TODAY EXCEPT IN SHOWERS AND THUNDERSTORMS.
THERE MAY BE CONVECTION AROUND THE FORECAST AREA MUCH OF THE DAY BUT
THE BEST CHANCE FOR THUNDER AT ANY OF THE TAF SITES APPEARS TO BE
18Z AND INTO THE EARLY EVENING. VARIABLE TO LIGHT SOUTHEAST WINDS
THIS MORNING BECOMING SOUTHWEST 10KT AFTER 14Z.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF CONVECTION.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 84 64 84 / 30 40 40 30
ATLANTA 67 83 66 82 / 20 40 40 30
BLAIRSVILLE 60 77 60 78 / 30 60 60 30
CARTERSVILLE 64 84 62 82 / 20 60 60 30
COLUMBUS 68 89 67 87 / 20 30 30 30
GAINESVILLE 65 83 64 81 / 20 50 50 30
MACON 63 87 65 86 / 20 30 30 30
ROME 64 84 61 83 / 30 60 60 30
PEACHTREE CITY 63 85 63 84 / 20 40 30 30
VIDALIA 68 89 69 88 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...30
LONG TERM....SNELSON
AVIATION...41
000
FXUS62 KCAE 220453
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1253 AM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
REST OF TONIGHT...CONTINUED HIGH LOW-LEVEL MOISTURE SHOULD SUPPORT
STRATUS AND AREAS OF FOG DURING THE EARLY MORNING HOURS. THE
CLOUDINESS SHOULD HELP HOLD UP TEMPERATURES. THE TEMPERATURE
FORECAST APPEARS ON TRACK WITH LOWS IN THE MIDDLE 60S.
TODAY...HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CONTINUE TO
CIRCULATE MOIST AIR INTO THE FORECAST AREA. THE NAM AND GFS
CONTINUE TO INDICATE A WEAK MID-LEVEL SHORTWAVE TROUGH LINGERING
OVER THE FORECAST AREA. EXPECT SCATTERED THUNDERSTORMS MAINLY
DURING THE TIME OF MAXIMUM HEATING. USED AN AVERAGE OF THE GFS AND
NAM MOS POPS. PRECIPITABLE WATER NEAR 1.7 OF AN INCH AND SLOW
STORM MOVEMENT SUPPORTS HEAVY RAIN WILL SOME OF THE THUNDERSTORMS.
HEAVY PRECIPITATION LOADINGS AND POSSIBLY MODERATE INSTABILITY
WITH H5 TEMPERATURES AROUND -10 SUPPORT A POSSIBILITY OF DAMAGING
WIND. USED THE WARMER TEMPERATURE GUIDANCE FOR TODAY BASED ON
YESTERDAY/S VERIFICATION.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
A CONTINUED MOIST SOUTH FLOW ASSOCIATED WITH THE OFFSHORE HIGH
PLUS A PRE-FRONTAL TROUGH SUPPORT THUNDERSTORMS TONIGHT. COVERAGE
WILL LIKELY BE LIMITED BY DIURNAL COOLING AND PREVIOUS CONVECTION.
THE NAM AND GFS MOS ARE IN GOOD AGREEMENT WITH POPS 30 TO 40 PERCENT.
THE MODELS SHOW THE PRE-FRONTAL TROUGH LINGERING THURSDAY BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE FORECAST AREA EARLY
AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE NAM AND GFS MOS
INDICATE VERY LOW POPS...BUT MAINTAINED CHANCE POPS BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE PRE-FRONTAL TROUGH THURSDAY AND
THE COLD FRONT THURSDAY EVENING. FURTHER DRYING SHOULD OCCUR
BEHIND THE FRONT BY LATE THURSDAY NIGHT. THE TEMPERATURE GUIDANCE
WAS CLOSE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
AND TUESDAY. THE GFS AND ECMWF MOS PLUS GFS ENSEMBLE MEAN SUPPORTS
VERY LOW POPS. EXPECT BELOW NORMAL TEMPERATURES DURING THE
WEEKEND AND NEAR NORMAL DURING THE REST OF THE MEDIUM RANGE
PERIOD.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
EXPECT SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS SHOULD DIMINISH
DURING THE EARLY MORNING HOURS. WITH CLEARING SKIES EXPECT AREAS OF
FOG AND STRATUS TO DEVELOP WHERE MOST OF THE RAIN FELL. WILL HAVE
FOG AND STRATUS IN ALL TAFS STARTING AROUND 09Z UNTIL 13Z...ALTHOUGH
LATEST OBS SUGGEST THAT IFR CONDITIONS MAY DEVELOP AT AGS SOONER
THAN 09Z. STRATUS AND FOG EXPECTED TO BURN OFF DURING THE EARLY TO
MID MORNING. LOW LEVEL MOISTURE WILL REMAIN HIGH. VFR CONDITIONS
DURING THE LATE MORNING AND AFTERNOON WITH SCATTERED THUNDERSTORMS
DEVELOPING AFTER 18Z.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KFFC 220252
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1052 PM EDT TUE MAY 21 2013
.UPDATE...
UPDATED TO INCLUDE SOME POPS THROUGH MIDNIGHT FOR WEST CENTRAL GA AS
WESTWARD MOVING OUTFLOW BOUNDARY LIKELY TO SPAWN A FEW MORE
THUNDERSTORMS. WATCHING CLOSELY STORMS ACROSS NORTH GA FOR
POSSIBLE LOCALIZED FF THREAT AS WELL. MOST STORMS HAVE BEEN
PRODUCING PEA TO NICKEL SIZED HAIL THIS EVE AND EXPECT TREND TO
CONTINUE THROUGH 4Z TO 5Z.
OTHER UPDATE WAS TO GRIDS WED AFTN AND EVE TO INCLUDE SMALL HAIL
AND GUSTY WINDS AS THERE APPEARS TO BE A MARGINAL SEVERE THREAT
DUE TO SLIGHTLY INCREASING DEEP LAYER SHEAR
PROFILES....PARTICULARLY ACROSS NW AND NE GA. WILL NEED TO MONITOR
FOR POTENTIALLY INCREASING SEVERE THREAT AFTER 3 PM WED.
&&
.PREV DISCUSSION... /ISSUED 805 PM EDT TUE MAY 21 2013/
PREV DISCUSSION... /ISSUED 314 PM EDT TUE MAY 21 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE IN GOOD AGREEMENT THROUGH THE SHORT TERM. AIRMASS
SHOWERS/TSTORMS DEVELOPING ACROSS THE CWA...MAINLY ACROSS THE
EXTREME NORTH AND EASTERN PARTS OF THE CWA. THESE WILL DISSIPATE
SHORTLY AFTER SUNSET THIS EVENING. THERE IS A POSSIBILITY THAT THE
STORMS OVER NORTHWEST AL AND CENTRAL TN COULD MAKE IT TO EXTREME
NORTHWEST GA BEFORE DIMINISHING THIS EVENING. THE H5 RIDGE OVER THE
EASTERN U.S. WILL WEAKEN AS THE CENTRAL U.S. TROUGH MOVES INTO THE
MISSISSIPPI VALLEY. THIS WILL PUSH A COLD FRONT INTO THE TENNESSEE
VALLEY WEDNESDAY WHICH WILL BRING A BETTER CHANCE OF THUNDERSTORMS
TO THE CWA...MAINLY ACROSS NORTH GA. INSTABILITY INCREASES WEDNESDAY
ACROSS NORTH GA AND THIS COULD PRODUCE A FEW STRONG STORMS. GUIDANCE
TEMPS LOOK GOOD FOR TONIGHT...ALTHOUGH TRICKY FOR WEDNESDAY WITH
ADDITIONAL CLOUDS. WILL TREND TO THE COOLER SIDE OF GUIDANCE ACROSS
NORTH GA FOR HIGHS ON WEDNESDAY DUE TO INCREASED CLOUDS AND PRECIP.
17
LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
BY WEDNESDAY EVENING...BOTH THE GFS AND ECMWF INDICATE THAT THE
FRONT WILL BE WEAKENING SIGNIFICANTLY. GFS REMAINS AB IT ON THE
STRONG SIDE WITH A SLIGHTLY MORE EAST WITH THE GREAT LAKES SURFACE
LOW. BOTH ARE TRANSITIONING THE UPPER LOW TO MORE OF A SHARP OPEN
TROUGH PHASING WITH THE LONGWAVE TROUGH IN CANADA. WEAK SHORTWAVE
OFF THE SOUTH CAROLINA COAST WILL LIFT NORTHEAST AND BE ABSORBED
BY THE LONGWAVE TROUGH AS WELL. SPC CONTINUES THE AREA IN GENERAL
THUNDER FOR THURSDAY...WITH MUCAPE VALUES 500-1000 J/KG EARLY IN
THE DAY...DECREASING BY MID-MORNING...AND INCREASING AGAIN IN
EXTREME SOUTHERN ZONES JUST AHEAD OF THE FRONT AFTER 18Z TO OVER
1000 J/KG. WILL HAVE TO MONITOR THE AREA FOR THE POTENTIAL FOR
ISOLATED STRONG STORMS BUT NOTHING TO SIGNIFICANT.
COLD FRONT SHOULD BE PUSHED THROUGH THE AREA BY LATE THURSDAY...
AND HAVE DECREASED TEMPS NORTHWEST SOMEWHAT TO LINE UP WITH THAT
TIMING A LITTLE BETTER. SHOULD SEE A SIGNIFICANT DECREASE IN TEMPS
TOWARD THE END OF THE WEEK WITH SURFACE HIGH PRESSURE BUILDING IN
AND NORTHWEST FLOW ALOFT...CURRENT FORECAST HAS HIGHS ON FRIDAY
ABOUT 5 DEGREES COOLER THAN HIGHS ON THURSDAY EXCEPT IN CENTRAL
GEORGIA. SEE PREVIOUS LONG TERM DISCUSSION BELOW.
TDP
AVIATION...
00Z UPDATE...
MOST OF THE SCATTERED CONVECTION AROUND ATL HAS DIED DOWN WITH
SUNSET...HOWEVER...OUTFLOW BOUNDARY WHICH SHOWS UP ON ATL TDWR AS
WELL AS BOUNDARY ON JGX RADAR NEAR MCN STILL INGNITING A FEW STORMS.
HAVE LEFT TS OUT FOR THE EVENING EXCEPT FOR ATL AND MCN WHICH
SHOULD GET A GLANCING BLOW OF THE CELLS IN EAST GA MOVING SW. HIGH
RES HRRR AND WRF INDICATING SOME DECENT STORM DEVELOPMENT AROUND
THE METRO ATL AIRPORTS BETWEEN 01Z AND 02Z ALONG THE WESTWARD
MOVING OUTFLOW BOUNDARY BUT NOT CONFIDENT ENOUGH IN THAT SCENARIO
TO INSERT INTO TAF...BUT WILL MONITOR FOR POSSIBLE AMD. HAVE
INTRODUCED PROB30 TO ALL TAF SITES TOMORROW AFTERNOON BETWEEN 19Z
AND 20Z AS 4 KM WRF SHOWING CONVECTIVE INITIATION AROUND THAT TIME
AS WEAK COLD FRONT AND REMNANT OUTFLOW MOVE INTO GA. WINDS SHOULD
GO GENERALLY CALM TONIGHT AND PICK UP OUT OF THE SSW BETWEEN 6 TO
10KTS AFTER AROUND 13Z WED.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON CONVECTION THIS EVENING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
KSTELLMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 84 64 84 / 30 40 40 30
ATLANTA 67 83 66 82 / 20 40 40 30
BLAIRSVILLE 60 77 60 78 / 30 60 60 30
CARTERSVILLE 64 84 62 82 / 20 60 60 30
COLUMBUS 68 89 67 87 / 20 30 30 30
GAINESVILLE 65 83 64 81 / 20 50 50 30
MACON 63 87 65 86 / 20 30 30 30
ROME 64 84 61 83 / 30 60 60 30
PEACHTREE CITY 63 85 63 84 / 20 40 30 30
VIDALIA 68 89 69 88 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...30
LONG TERM....SNELSON
AVIATION...SNELSON
000
FXUS62 KCHS 220203
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1003 PM EDT TUE MAY 21 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A
COLD FRONT WILL MOVE THROUGH THE AREA ON FRIDAY WITH DRY HIGH
PRESSURE BUILDING IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE FORECAST AREA LIES UNDERNEATH A WELL-DEFINED MID LEVEL
IMPULSE ACROSS FLORIDA WITH STRUNG OUT VORTICITY STRETCHING NORTH
AND NE OVERHEAD TO OFF THE COAST OF NC AND SE VA. THIS FEATURE
WILL MOVE LITTLE THROUGH THE NIGHT. MEANWHILE...THE BERMUDA HIGH
WILL LIE ATOP THE REGION AS A SUBTLE TROUGH DEVELOPS OVER THE
NEARBY ATLANTIC LATE.
MUCH OF THE NIGHT WILL BE RAINFREE...ALTHOUGH WITH THE SHORT WAVE
ALOFT AND SOME CONVERGENCE DOWNSTAIRS...GIVEN THAT PWATS ARE NEAR
2 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE MAY...WE LOOK FOR AN
INCREASE IN CONVECTION AGAIN OVER THE ATLANTIC OVERNIGHT. WE/RE
ALREADY SEEING SIGNS OF THAT OUT NEAR THE GULF STREAM. WITHIN THE
SOUTHERLY SYNOPTIC FLOW WE ANTICIPATE SOME OF THIS ACTIVITY WILL
MOVE INTO CHARLESTON AND FAR SE BERKELEY COUNTY BY SUNRISE.
GIVEN THE COPIOUS AMOUNT OF RAINS FROM EARLIER TODAY...FOG WILL
BECOME PROBLEMATIC AGAIN OVERNIGHT AS THE MID/HIGH LEVEL
CONVECTIVE DEBRIS CLOUD COVER DIMINISHES. WE HAVE EXPANDED THE
PATCHY FOG A LITTLE FURTHER SE WITH THE LATE EVENING UPDATE...AND
INCLUDED AREAS OF FOG ALONG PARTS OF THE NW TIER WHERE SOME OF THE
BETTER RAINFALL OCCURRED. LOCALLY DENSE FOG IS CERTAINLY A CONCERN
AND WE WILL RE-EVALUATE AGAIN WITH FUTURE UPDATES.
CONDITIONS WILL BE STICKY AND BALMY TONIGHT...WITH MINIMUM TEMPS
NO LOWER THAN THE MID-UPPER 60S INLAND AND AROUND 70 NEAR THE SHORE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY AND THURSDAY WITH
BROAD UPPER TROUGHING INLAND AND HIGH PRESSURE OVER THE ATLANTIC.
THIS PATTERN WILL MAINTAIN DEEP MOISTURE OVER THE AREA WITH DECENT
RAIN CHANCES THROUGH THE PERIOD...MOSTLY CONFINED INLAND DURING THE
DAY AND OVER THE ATLANTIC AT NIGHT. THE RISK FOR SEVERE WEATHER
APPEARS LOW GIVEN THE LACK OF ORGANIZATION POTENTIAL...ALTHOUGH
HEAVY RAINFALL COULD RESULT IN LOCALIZED FLOODING. HIGH/LOW
TEMPERATURES WILL ULTIMATELY DEPEND ON CLOUD COVER/RAINFALL BUT
GENERALLY SHOULD BE CLOSE TO SLIGHTLY ABOVE NORMAL.
A COLD FRONT SHOULD PUSH THROUGH FRIDAY MORNING...ALTHOUGH THE
NORTHWEST DOWNSLOPE FLOW WILL HELP TO OFFSET THE COLD ADVECTION.
THIS SHOULD LEAD TO TEMPERATURES CLOSE TO NORMAL IN THE MID 80S. THE
BIGGER CHANGE WILL BE THE DRIER AIR WHICH WILL MAKE IT FEEL A LOT
MORE COMFORTABLE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
MAINLY VFR CONDITIONS AT BOTH TERMINALS THROUGH THE NIGHT AND
EARLY WEDNESDAY. COULD SEE A FEW HOURS OF MVFR CONDITIONS AS LOW
STRATUS AND LIGHT FOG ATTEMPT TO FORM CLOSER TO DAYBREAK.
ANOTHER ROUND OF SCATTERED CONVECTION WILL OCCUR LATE WEDNESDAY
MORNING INTO THE AFTERNOON...BRINGING WITH IT THE POSSIBILITY OF
SHRA AND TSRA. FOR NOW PROB30 GROUPS WILL SUFFICE UNTIL TRENDS
PAINT A BETTER PICTURE. PERIODIC MVFR CONDITIONS WITH GUSTY WINDS
CAN OCCUR IN ANY TSRA THAT DOES IMPACT THE TERMINALS.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
TONIGHT...THE TYPICAL SUB-TROPICAL RIDGE OF HIGH PRESSURE WILL
CONTINUE TO STRETCH ACROSS THE COASTAL WATERS...GENERATING SE AND
SOUTH WINDS OF LESS THAN 10 OR 15 KT. SEAS WILL HOLD IN A FAIRLY
STEADY STATE AT 2-4 FT...MAINLY IN A SE SWELL. WHILE THE RISK IS NOT
PARTICULARLY HIGH...THERE IS NONETHELESS A CHANCE OF ISOLATED
STRONGER STORMS MOVING IN AFTER 06Z.
WEDNESDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES THROUGH FRIDAY. THE
MUCH COOLER AND DRIER AIR MASS BEHIND THE FRONT WILL MOVE IN AND
LEAD TO INCREASING WINDS AND BUILDING SEAS...POSSIBLY REACHING
ADVISORY LEVELS...AT LEAST ACROSS THE WATERS BEYOND 20 NM.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AS WELL AS MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE BUT MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...RJB
LONG TERM...JRL
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 220111
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
911 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SHOWERS AND THUNDERSTORMS HAVE DISSIPATED ACROSS THE AREA. MOSTLY
CLOUDY THIS EVENING WITH SOME CLEARING AFTER MIDNIGHT MAY LEAD TO
LOW CLOUDS AND FOG TOWARD MORNING DUE TO HIGH LOW-LEVEL MOISTURE
AND LIGHT WINDS. TEMPERATURES FALLING INTO THE MIDDLE 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY AND WEDNESDAY NIGHT...LOW PRESSURE WILL CONTINUE MOVING
THROUGH THE CENTRAL GREAT LAKES WITH HIGH PRESSURE OFF THE MID
ATLANTIC COAST. THIS WILL CONTINUE THE SOUTHERLY WINDS AND
MOISTURE ADVECTION INTO THE AREA ALONG WITH INSTABILITY. RESULT
WILL BE ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION WITH THE
GREATEST POTENTIAL ACROSS THE EASTERN MIDLANDS. WITH PWAT VALUES
REMAINING IN THE 1.6 TO 1.7 INCH RANGE THE POSSIBILITY OF HEAVY
RAINFALL WILL BE THE MAIN THREAT CAUSING STANDING WATER IN LOW
LYING AND POOR DRAINAGE AREAS. WITH THE UPPER TROUGH MOVING AWAY
FROM THE AREA AND UPPER HEIGHTS RISING SLIGHTLY TEMPERATURES WILL
BE SLIGHTLY HIGHER WITH MID 80S FOR MOST LOCATIONS. CONVECTION
WILL DIMINISH WITH SUNSET...HOWEVER WITH THE COLD FRONT
APPROACHING FROM THE WEST THERE IS SOME POTENTIAL FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT MAINLY OVER THE WESTERN MIDLANDS.
OVERNIGHT LOWS WILL GENERALLY BE IN THE MID 60S.
THURSDAY AND THURSDAY NIGHT...THURSDAY WILL SEE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT CROSSES THE REGION.
ALTHOUGH MODELS DIFFER SLIGHTLY ON TIMING OF FROPA INDICATIONS ARE
FOR LATE MORNING TO EARLY AFTERNOON. THIS WILL ALLOW THE BEST
HEATING OVER THE EASTERN MIDLANDS ALONG WITH THE BEST CHANCE OF
CONVECTION. PWAT VALUES WILL AGAIN BE IN EXCESS OF 1.6 INCHES
CONTINUING THE THREAT FOR HEAVY RAIN. THE FRONT WILL MOVE OFFSHORE
DURING THE AFTERNOON HOURS WITH THE CHANCES OF SHOWERS DIMINISHING
RAPIDLY THROUGH THE EVENING HOURS AS DRIER AIR BEGINS TO PUSH INTO
THE FORECAST AREA. DAYTIME HIGHS WILL BE IN THE MID 80S WITH
OVERNIGHT LOWS IN THE MID 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
LOCATION DIFFERENCES APPEARING FOR SUNDAY INTO TUESDAY. PATTERN
WILL REMAIN ACTIVE AS HIGH PRESSURE AND DRIER AIR MOVE INTO THE
AREA ON FRIDAY AND FRIDAY NIGHT. ON SATURDAY AFTERNOON THE HIGH
WILL SLIDE SO THE SOUTHEAST AS THE NEXT LOW PRESSURE SYSTEM SLOWLY
TRIES TO DEVELOP OVER THE CENTRAL US. THIS WILL PUSH A FRONTAL
BOUNDARY TOWARD THE REGION ON SUNDAY...WITH THE GFS KEEPING THE
FRONT FURTHER NORTH AND THE ECMWF HAVING THE FRONT ALONG THE NC/SC
BORDER. BY MONDAY THE GFS HAS PUSHED THE FRONT INTO SOUTHERN NC
WITH THE ECMWF OVER THE NORTHERN MIDLANDS. HAVE GONE WITH A
COMPROMISE OF THE ECMWF AND GFS FOR THE LATTER HALF OF THE LONG
TERM WHICH CURRENTLY KEEPS THE AREA RAIN FREE THROUGH THE END OF
THE LONG TERM...HOWEVER CONFIDENCE IS LOW FOR SUNDAY THROUGH
TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
EXPECT SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS SHOULD
DIMINISH AFTER MIDNIGHT. WITH CLEARING SKIES EXPECT AREAS OF FOG
AND STRATUS TO DEVELOP WHERE MOST OF THE RAIN FELL. WILL HAVE FOG
AND STRATUS IN ALL TAFS STARTING AROUND 09Z UNTIL 13Z. STRATUS AND
FOG EXPECTED TO BURN OFF DURING THE EARLY TO MID MORNING. LOW LEVEL
MOISTURE WILL REMAIN HIGH. VFR CONDITIONS DURING THE LATE MORNING
AND AFTERNOON WITH SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
000
FXUS62 KCAE 220028
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
828 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SATELLITE AND RADAR TRENDS AT 2145Z INDICATE SCATTERED THUNDERSTORM
FOCUS NOW IN THE CSRA EARLY THIS EVENING. POPS DECREASING TO THE
NORTH ACROSS THE MIDLANDS. THUNDERSTORMS SHOULD DIMINISH DURING
THE NEXT COUPLE OF HOURS.
LOWS WILL FALL INTO THE MIDDLE 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY AND WEDNESDAY NIGHT...LOW PRESSURE WILL CONTINUE MOVING
THROUGH THE CENTRAL GREAT LAKES WITH HIGH PRESSURE OFF THE MID
ATLANTIC COAST. THIS WILL CONTINUE THE SOUTHERLY WINDS AND
MOISTURE ADVECTION INTO THE AREA ALONG WITH INSTABILITY. RESULT
WILL BE ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION WITH THE
GREATEST POTENTIAL ACROSS THE EASTERN MIDLANDS. WITH PWAT VALUES
REMAINING IN THE 1.6 TO 1.7 INCH RANGE THE POSSIBILITY OF HEAVY
RAINFALL WILL BE THE MAIN THREAT CAUSING STANDING WATER IN LOW
LYING AND POOR DRAINAGE AREAS. WITH THE UPPER TROUGH MOVING AWAY
FROM THE AREA AND UPPER HEIGHTS RISING SLIGHTLY TEMPERATURES WILL
BE SLIGHTLY HIGHER WITH MID 80S FOR MOST LOCATIONS. CONVECTION
WILL DIMINISH WITH SUNSET...HOWEVER WITH THE COLD FRONT
APPROACHING FROM THE WEST THERE IS SOME POTENTIAL FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT MAINLY OVER THE WESTERN MIDLANDS.
OVERNIGHT LOWS WILL GENERALLY BE IN THE MID 60S.
THURSDAY AND THURSDAY NIGHT...THURSDAY WILL SEE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT CROSSES THE REGION.
ALTHOUGH MODELS DIFFER SLIGHTLY ON TIMING OF FROPA INDICATIONS ARE
FOR LATE MORNING TO EARLY AFTERNOON. THIS WILL ALLOW THE BEST
HEATING OVER THE EASTERN MIDLANDS ALONG WITH THE BEST CHANCE OF
CONVECTION. PWAT VALUES WILL AGAIN BE IN EXCESS OF 1.6 INCHES
CONTINUING THE THREAT FOR HEAVY RAIN. THE FRONT WILL MOVE OFFSHORE
DURING THE AFTERNOON HOURS WITH THE CHANCES OF SHOWERS DIMINISHING
RAPIDLY THROUGH THE EVENING HOURS AS DRIER AIR BEGINS TO PUSH INTO
THE FORECAST AREA. DAYTIME HIGHS WILL BE IN THE MID 80S WITH
OVERNIGHT LOWS IN THE MID 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
LOCATION DIFFERENCES APPEARING FOR SUNDAY INTO TUESDAY. PATTERN
WILL REMAIN ACTIVE AS HIGH PRESSURE AND DRIER AIR MOVE INTO THE
AREA ON FRIDAY AND FRIDAY NIGHT. ON SATURDAY AFTERNOON THE HIGH
WILL SLIDE SO THE SOUTHEAST AS THE NEXT LOW PRESSURE SYSTEM SLOWLY
TRIES TO DEVELOP OVER THE CENTRAL US. THIS WILL PUSH A FRONTAL
BOUNDARY TOWARD THE REGION ON SUNDAY...WITH THE GFS KEEPING THE
FRONT FURTHER NORTH AND THE ECMWF HAVING THE FRONT ALONG THE NC/SC
BORDER. BY MONDAY THE GFS HAS PUSHED THE FRONT INTO SOUTHERN NC
WITH THE ECMWF OVER THE NORTHERN MIDLANDS. HAVE GONE WITH A
COMPROMISE OF THE ECMWF AND GFS FOR THE LATTER HALF OF THE LONG
TERM WHICH CURRENTLY KEEPS THE AREA RAIN FREE THROUGH THE END OF
THE LONG TERM...HOWEVER CONFIDENCE IS LOW FOR SUNDAY THROUGH
TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
EXPECT SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS SHOULD
DIMINISH AFTER MIDNIGHT. WITH CLEARING SKIES EXPECT AREAS OF FOG
AND STRATUS TO DEVELOP WHERE MOST OF THE RAIN FELL. WILL HAVE FOG
AND STRATUS IN ALL TAFS STARTING AROUND 09Z UNTIL 13Z. STRATUS AND
FOG EXPECTED TO BURN OFF DURING THE EARLY TO MID MORNING. LOW LEVEL
MOISTURE WILL REMAIN HIGH. VFR CONDITIONS DURING THE LATE MORNING
AND AFTERNOON WITH SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
000
FXUS62 KFFC 220005
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
805 PM EDT TUE MAY 21 2013
.PREV DISCUSSION... /ISSUED 314 PM EDT TUE MAY 21 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE IN GOOD AGREEMENT THROUGH THE SHORT TERM. AIRMASS
SHOWERS/TSTORMS DEVELOPING ACROSS THE CWA...MAINLY ACROSS THE
EXTREME NORTH AND EASTERN PARTS OF THE CWA. THESE WILL DISSIPATE
SHORTLY AFTER SUNSET THIS EVENING. THERE IS A POSSIBILITY THAT THE
STORMS OVER NORTHWEST AL AND CENTRAL TN COULD MAKE IT TO EXTREME
NORTHWEST GA BEFORE DIMINISHING THIS EVENING. THE H5 RIDGE OVER THE
EASTERN U.S. WILL WEAKEN AS THE CENTRAL U.S. TROUGH MOVES INTO THE
MISSISSIPPI VALLEY. THIS WILL PUSH A COLD FRONT INTO THE TENNESSEE
VALLEY WEDNESDAY WHICH WILL BRING A BETTER CHANCE OF THUNDERSTORMS
TO THE CWA...MAINLY ACROSS NORTH GA. INSTABILITY INCREASES WEDNESDAY
ACROSS NORTH GA AND THIS COULD PRODUCE A FEW STRONG STORMS. GUIDANCE
TEMPS LOOK GOOD FOR TONIGHT...ALTHOUGH TRICKY FOR WEDNESDAY WITH
ADDITIONAL CLOUDS. WILL TREND TO THE COOLER SIDE OF GUIDANCE ACROSS
NORTH GA FOR HIGHS ON WEDNESDAY DUE TO INCREASED CLOUDS AND PRECIP.
17
LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
BY WEDNESDAY EVENING...BOTH THE GFS AND ECMWF INDICATE THAT THE
FRONT WILL BE WEAKENING SIGNIFICANTLY. GFS REMAINS AB IT ON THE
STRONG SIDE WITH A SLIGHTLY MORE EAST WITH THE GREAT LAKES SURFACE
LOW. BOTH ARE TRANSITIONING THE UPPER LOW TO MORE OF A SHARP OPEN
TROUGH PHASING WITH THE LONGWAVE TROUGH IN CANADA. WEAK SHORTWAVE
OFF THE SOUTH CAROLINA COAST WILL LIFT NORTHEAST AND BE ABSORBED
BY THE LONGWAVE TROUGH AS WELL. SPC CONTINUES THE AREA IN GENERAL
THUNDER FOR THURSDAY...WITH MUCAPE VALUES 500-1000 J/KG EARLY IN
THE DAY...DECREASING BY MID-MORNING...AND INCREASING AGAIN IN
EXTREME SOUTHERN ZONES JUST AHEAD OF THE FRONT AFTER 18Z TO OVER
1000 J/KG. WILL HAVE TO MONITOR THE AREA FOR THE POTENTIAL FOR
ISOLATED STRONG STORMS BUT NOTHING TO SIGNIFICANT.
COLD FRONT SHOULD BE PUSHED THROUGH THE AREA BY LATE THURSDAY...
AND HAVE DECREASED TEMPS NORTHWEST SOMEWHAT TO LINE UP WITH THAT
TIMING A LITTLE BETTER. SHOULD SEE A SIGNIFICANT DECREASE IN TEMPS
TOWARD THE END OF THE WEEK WITH SURFACE HIGH PRESSURE BUILDING IN
AND NORTHWEST FLOW ALOFT...CURRENT FORECAST HAS HIGHS ON FRIDAY
ABOUT 5 DEGREES COOLER THAN HIGHS ON THURSDAY EXCEPT IN CENTRAL
GEORGIA. SEE PREVIOUS LONG TERM DISCUSSION BELOW.
TDP
&&
.AVIATION...
00Z UPDATE...
MOST OF THE SCATTERED CONVECTION AROUND ATL HAS DIED DOWN WITH
SUNSET...HOWEVER...OUTFLOW BOUNDARY WHICH SHOWS UP ON ATL TDWR AS
WELL AS BOUNDARY ON JGX RADAR NEAR MCN STILL INGNITING A FEW STORMS.
HAVE LEFT TS OUT FOR THE EVENING EXCEPT FOR ATL AND MCN WHICH
SHOULD GET A GLANCING BLOW OF THE CELLS IN EAST GA MOVING SW. HIGH
RES HRRR AND WRF INDICATING SOME DECENT STORM DEVELOPMENT AROUND
THE METRO ATL AIRPORTS BETWEEN 01Z AND 02Z ALONG THE WESTWARD
MOVING OUTFLOW BOUNDARY BUT NOT CONFIDENT ENOUGH IN THAT SCENARIO
TO INSERT INTO TAF...BUT WILL MONITOR FOR POSSIBLE AMD. HAVE
INTRODUCED PROB30 TO ALL TAF SITES TOMORROW AFTERNOON BETWEEN 19Z
AND 20Z AS 4 KM WRF SHOWING CONVECTIVE INITIATION AROUND THAT TIME
AS WEAK COLD FRONT AND REMNANT OUTFLOW MOVE INTO GA. WINDS SHOULD
GO GENERALLY CALM TONIGHT AND PICK UP OUT OF THE SSW BETWEEN 6 TO
10KTS AFTER AROUND 13Z WED.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON CONVECTION THIS EVENING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
KSTELLMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 84 64 84 / 30 40 40 30
ATLANTA 67 83 66 82 / 20 40 40 30
BLAIRSVILLE 60 77 60 78 / 30 60 50 30
CARTERSVILLE 64 84 62 82 / 20 60 40 30
COLUMBUS 68 89 67 87 / 20 30 30 30
GAINESVILLE 65 83 64 81 / 20 50 40 30
MACON 63 87 65 86 / 20 30 30 30
ROME 64 84 61 83 / 30 60 40 30
PEACHTREE CITY 63 85 63 84 / 20 40 30 30
VIDALIA 68 89 69 88 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...30
LONG TERM....SNELSON
AVIATION...SNELSON
000
FXUS62 KCHS 212344
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
744 PM EDT TUE MAY 21 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A
COLD FRONT WILL MOVE THROUGH THE AREA ON FRIDAY WITH DRY HIGH
PRESSURE BUILDING IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
GIVEN THE LOSS OF DAYTIME HEATING AND DECREASING
INSTABILITY...LINGERING CONVECTION WEST OF I-95 IN SE GA WILL COME
TO AN END BY 10 PM. AN ISOLATED STRONG STORM CAN STILL OCCUR WEST
AND NW OF KSAV BEFORE ENDING.
THE FORECAST AREA LIES UNDERNEATH A WELL-DEFINED MID LEVEL IMPULSE
ACROSS FLORIDA WITH STRUNG OUT VORTICITY STRETCHING NORTH AND NE
OVERHEAD TO OFF THE COAST OF NC AND SE VA. THIS FEATURE WILL MOVE
LITTLE THROUGH THE NIGHT. MEANWHILE...THE BERMUDA HIGH WILL LIE
ATOP THE REGION AS A SUBTLE TROUGH DEVELOPS OVER THE NEARBY
ATLANTIC LATE.
MUCH OF THE REST OF THE NIGHT WILL BE RAINFREE...ALTHOUGH WITH THE
SHORT WAVE ALOFT AND SOME CONVERGENCE DOWNSTAIRS...GIVEN THAT
PWATS ARE NEAR 2 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE
MAY...WE LOOK FOR SOME CONVECTION TO BREAK OUT AGAIN OVER THE
ATLANTIC OVERNIGHT. WE/RE ALREADY SEEING SIGNS OF THAT OUT NEAR
THE GULF STREAM. SOME OF THIS ACTIVITY WILL MOVE INTO CHARLESTON
AND FAR SE BERKELEY COUNTY BY SUNRISE.
GIVEN THE COPIOUS AMOUNT OF RAINS FROM EARLIER TODAY...FOG WILL
BECOME PROBLEMATIC AGAIN OVERNIGHT WHERE CLOUD COVER DIMINISHES.
WE HAVE ADDED PATCHY FOG TO THE GRIDDED FORECAST OVER THE WESTERN
HALF OF THE CWFA...GIVEN THE ONSHORE SYNOPTIC FLOW. LOCALLY DENSE
FOG IS CERTAINLY A CONCERN AND WE WILL RE-EVALUATE AGAIN WITH
FUTURE UPDATES.
CONDITIONS WILL BE STICKY AND BALMY TONIGHT...WITH MINIMUM TEMPS
NO LOWER THAN THE MID-UPPER 60S INLAND AND AROUND 70 NEAR THE SHORE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY AND THURSDAY WITH
BROAD UPPER TROUGHING INLAND AND HIGH PRESSURE OVER THE ATLANTIC.
THIS PATTERN WILL MAINTAIN DEEP MOISTURE OVER THE AREA WITH DECENT
RAIN CHANCES THROUGH THE PERIOD...MOSTLY CONFINED INLAND DURING THE
DAY AND OVER THE ATLANTIC AT NIGHT. THE RISK FOR SEVERE WEATHER
APPEARS LOW GIVEN THE LACK OF ORGANIZATION POTENTIAL...ALTHOUGH
HEAVY RAINFALL COULD RESULT IN LOCALIZED FLOODING. HIGH/LOW
TEMPERATURES WILL ULTIMATELY DEPEND ON CLOUD COVER/RAINFALL BUT
GENERALLY SHOULD BE CLOSE TO SLIGHTLY ABOVE NORMAL.
A COLD FRONT SHOULD PUSH THROUGH FRIDAY MORNING...ALTHOUGH THE
NORTHWEST DOWNSLOPE FLOW WILL HELP TO OFFSET THE COLD ADVECTION.
THIS SHOULD LEAD TO TEMPERATURES CLOSE TO NORMAL IN THE MID 80S. THE
BIGGER CHANGE WILL BE THE DRIER AIR WHICH WILL MAKE IT FEEL A LOT
MORE COMFORTABLE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
DIMINISHING CONVECTION NEAR KSAV WILL END THIS EVENING...OTHERWISE
MAINLY VFR AT BOTH TERMINALS THROUGH THE NIGHT AND EARLY
WEDNESDAY. COULD SEE A FEW HOURS OF MVFR CONDITIONS AS LOW STRATUS
AND LIGHT FOG ATTEMPT TO FORM CLOSER TO DAYBREAK.
ANOTHER ROUND OF SCATTERED CONVECTION WILL OCCUR LATE WEDNESDAY
MORNING INTO THE AFTERNOON...BRINGING WITH IT THE POSSIBILITY OF
SHRA AND TSRA. FOR NOW PROB30 GROUPS WILL SUFFICE UNTIL TRENDS
PAINT A BETTER PICTURE. PERIODIC MVFR CONDITIONS WITH GUSTY WINDS
CAN OCCUR IN ANY TSRA THAT DOES IMPACT THE TERMINALS.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
TONIGHT...THE TYPICAL SUB-TROPICAL RIDGE OF HIGH PRESSURE WILL
CONTINUE TO STRETCH ACROSS THE COASTAL WATERS...GENERATING SE AND
SOUTH WINDS OF LESS THAN 10 OR 15 KT. SEAS WILL HOLD IN A FAIRLY
STEADY STATE...AVERAGING 2-4 FT. WHILE THE RISK IS NOT
PARTICULARLY HIGH...THERE IS NONETHELESS A CHANCE OF ISOLATED
STRONGER STORMS MOVING IN AFTER MIDNIGHT.
WEDNESDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES THROUGH FRIDAY. THE
MUCH COOLER AND DRIER AIR MASS BEHIND THE FRONT WILL MOVE IN AND
LEAD TO INCREASING WINDS AND BUILDING SEAS...POSSIBLY REACHING
ADVISORY LEVELS...AT LEAST ACROSS THE WATERS BEYOND 20 NM.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AS WELL AS MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE BUT MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...RJB
LONG TERM...JRL
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 212306
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
706 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SATELLITE AND RADAR TRENDS AT 2145Z INDICATE SCATTERED THUNDERSTORM
FOCUS NOW IN THE CSRA EARLY THIS EVENING. POPS DECREASING TO THE
NORTH ACROSS THE MIDLANDS. THUNDERSTORMS SHOULD DIMINISH DURING
THE NEXT COUPLE OF HOURS.
LOWS WILL FALL INTO THE MIDDLE 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY AND WEDNESDAY NIGHT...LOW PRESSURE WILL CONTINUE MOVING
THROUGH THE CENTRAL GREAT LAKES WITH HIGH PRESSURE OFF THE MID
ATLANTIC COAST. THIS WILL CONTINUE THE SOUTHERLY WINDS AND
MOISTURE ADVECTION INTO THE AREA ALONG WITH INSTABILITY. RESULT
WILL BE ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION WITH THE
GREATEST POTENTIAL ACROSS THE EASTERN MIDLANDS. WITH PWAT VALUES
REMAINING IN THE 1.6 TO 1.7 INCH RANGE THE POSSIBILITY OF HEAVY
RAINFALL WILL BE THE MAIN THREAT CAUSING STANDING WATER IN LOW
LYING AND POOR DRAINAGE AREAS. WITH THE UPPER TROUGH MOVING AWAY
FROM THE AREA AND UPPER HEIGHTS RISING SLIGHTLY TEMPERATURES WILL
BE SLIGHTLY HIGHER WITH MID 80S FOR MOST LOCATIONS. CONVECTION
WILL DIMINISH WITH SUNSET...HOWEVER WITH THE COLD FRONT
APPROACHING FROM THE WEST THERE IS SOME POTENTIAL FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT MAINLY OVER THE WESTERN MIDLANDS.
OVERNIGHT LOWS WILL GENERALLY BE IN THE MID 60S.
THURSDAY AND THURSDAY NIGHT...THURSDAY WILL SEE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT CROSSES THE REGION.
ALTHOUGH MODELS DIFFER SLIGHTLY ON TIMING OF FROPA INDICATIONS ARE
FOR LATE MORNING TO EARLY AFTERNOON. THIS WILL ALLOW THE BEST
HEATING OVER THE EASTERN MIDLANDS ALONG WITH THE BEST CHANCE OF
CONVECTION. PWAT VALUES WILL AGAIN BE IN EXCESS OF 1.6 INCHES
CONTINUING THE THREAT FOR HEAVY RAIN. THE FRONT WILL MOVE OFFSHORE
DURING THE AFTERNOON HOURS WITH THE CHANCES OF SHOWERS DIMINISHING
RAPIDLY THROUGH THE EVENING HOURS AS DRIER AIR BEGINS TO PUSH INTO
THE FORECAST AREA. DAYTIME HIGHS WILL BE IN THE MID 80S WITH
OVERNIGHT LOWS IN THE MID 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
LOCATION DIFFERENCES APPEARING FOR SUNDAY INTO TUESDAY. PATTERN
WILL REMAIN ACTIVE AS HIGH PRESSURE AND DRIER AIR MOVE INTO THE
AREA ON FRIDAY AND FRIDAY NIGHT. ON SATURDAY AFTERNOON THE HIGH
WILL SLIDE SO THE SOUTHEAST AS THE NEXT LOW PRESSURE SYSTEM SLOWLY
TRIES TO DEVELOP OVER THE CENTRAL US. THIS WILL PUSH A FRONTAL
BOUNDARY TOWARD THE REGION ON SUNDAY...WITH THE GFS KEEPING THE
FRONT FURTHER NORTH AND THE ECMWF HAVING THE FRONT ALONG THE NC/SC
BORDER. BY MONDAY THE GFS HAS PUSHED THE FRONT INTO SOUTHERN NC
WITH THE ECMWF OVER THE NORTHERN MIDLANDS. HAVE GONE WITH A
COMPROMISE OF THE ECMWF AND GFS FOR THE LATTER HALF OF THE LONG
TERM WHICH CURRENTLY KEEPS THE AREA RAIN FREE THROUGH THE END OF
THE LONG TERM...HOWEVER CONFIDENCE IS LOW FOR SUNDAY THROUGH
TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
LOW CLOUDS HAVE DEVELOPED OVER MUCH OF THE AREA EARLY THIS MORNING.
CIGS MOSTLY IN THE IFR/LIFR RANGE...WITH LIFR VSBYS AT AGS. CAE VWP
INDICATING 20 KT LOW-LEVEL JET. FOG AND LOW STRATUS SHOULD DISSIPATE
BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE PERIOD.
WINDS WILL PICK UP OUT OF THE SOUTH TO SOUTHEAST AROUND 5-7 KNOTS.
WIDELY SCTD CONVECTION POSSIBLE LATER THIS AFTERNOON BUT NOT ENOUGH
CONFIDENCE TO MENTION AT ANY OF THE TAF SITES AT THIS TIME. MODEL
DATA SEEMS TO INDICATE THAT BULK OF CONVECTION THAT MAY DEVELOP
LATER THIS AFTERNOON MAY BE EAST OF THE TAF SITES. SOME MVFR FOG MAY
DEVELOP EARLY WEDNESDAY MORNING TOWARDS THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
000
FXUS62 KCAE 212251
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
651 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SATELLITE AND RADAR TRENDS AT 2145Z INDICATE SCATTERED THUNDERSTORM
FOCUS NOW IN THE CSRA EARLY THIS EVENING. POPS DECREASING TO THE
NORTH ACROSS THE MIDLANDS. THUNDERSTORMS SHOULD DIMINISH DURING
THE NEXT COUPLE OF HOURS.
LOWS WILL FALL INTO THE MIDDLE 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WEDNESDAY AND WEDNESDAY NIGHT...LOW PRESSURE WILL CONTINUE MOVING
THROUGH THE CENTRAL GREAT LAKES WITH HIGH PRESSURE OFF THE MID
ATLANTIC COAST. THIS WILL CONTINUE THE SOUTHERLY WINDS AND
MOISTURE ADVECTION INTO THE AREA ALONG WITH INSTABILITY. RESULT
WILL BE ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION WITH THE
GREATEST POTENTIAL ACROSS THE EASTERN MIDLANDS. WITH PWAT VALUES
REMAINING IN THE 1.6 TO 1.7 INCH RANGE THE POSSIBILITY OF HEAVY
RAINFALL WILL BE THE MAIN THREAT CAUSING STANDING WATER IN LOW
LYING AND POOR DRAINAGE AREAS. WITH THE UPPER TROUGH MOVING AWAY
FROM THE AREA AND UPPER HEIGHTS RISING SLIGHTLY TEMPERATURES WILL
BE SLIGHTLY HIGHER WITH MID 80S FOR MOST LOCATIONS. CONVECTION
WILL DIMINISH WITH SUNSET...HOWEVER WITH THE COLD FRONT
APPROACHING FROM THE WEST THERE IS SOME POTENTIAL FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT MAINLY OVER THE WESTERN MIDLANDS.
OVERNIGHT LOWS WILL GENERALLY BE IN THE MID 60S.
THURSDAY AND THURSDAY NIGHT...THURSDAY WILL SEE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT CROSSES THE REGION.
ALTHOUGH MODELS DIFFER SLIGHTLY ON TIMING OF FROPA INDICATIONS ARE
FOR LATE MORNING TO EARLY AFTERNOON. THIS WILL ALLOW THE BEST
HEATING OVER THE EASTERN MIDLANDS ALONG WITH THE BEST CHANCE OF
CONVECTION. PWAT VALUES WILL AGAIN BE IN EXCESS OF 1.6 INCHES
CONTINUING THE THREAT FOR HEAVY RAIN. THE FRONT WILL MOVE OFFSHORE
DURING THE AFTERNOON HOURS WITH THE CHANCES OF SHOWERS DIMINISHING
RAPIDLY THROUGH THE EVENING HOURS AS DRIER AIR BEGINS TO PUSH INTO
THE FORECAST AREA. DAYTIME HIGHS WILL BE IN THE MID 80S WITH
OVERNIGHT LOWS IN THE MID 60S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
LOCATION DIFFERENCES APPEARING FOR SUNDAY INTO TUESDAY. PATTERN
WILL REMAIN ACTIVE AS HIGH PRESSURE AND DRIER AIR MOVE INTO THE
AREA ON FRIDAY AND FRIDAY NIGHT. ON SATURDAY AFTERNOON THE HIGH
WILL SLIDE SO THE SOUTHEAST AS THE NEXT LOW PRESSURE SYSTEM SLOWLY
TRIES TO DEVELOP OVER THE CENTRAL US. THIS WILL PUSH A FRONTAL
BOUNDARY TOWARD THE REGION ON SUNDAY...WITH THE GFS KEEPING THE
FRONT FURTHER NORTH AND THE ECMWF HAVING THE FRONT ALONG THE NC/SC
BORDER. BY MONDAY THE GFS HAS PUSHED THE FRONT INTO SOUTHERN NC
WITH THE ECMWF OVER THE NORTHERN MIDLANDS. HAVE GONE WITH A
COMPROMISE OF THE ECMWF AND GFS FOR THE LATTER HALF OF THE LONG
TERM WHICH CURRENTLY KEEPS THE AREA RAIN FREE THROUGH THE END OF
THE LONG TERM...HOWEVER CONFIDENCE IS LOW FOR SUNDAY THROUGH
TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
LOW CLOUDS HAVE DEVELOPED OVER MUCH OF THE AREA EARLY THIS MORNING.
CIGS MOSTLY IN THE IFR/LIFR RANGE...WITH LIFR VSBYS AT AGS. CAE VWP
INDICATING 20 KT LOW-LEVEL JET. FOG AND LOW STRATUS SHOULD DISSIPATE
BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE PERIOD.
WINDS WILL PICK UP OUT OF THE SOUTH TO SOUTHEAST AROUND 5-7 KNOTS.
WIDELY SCTD CONVECTION POSSIBLE LATER THIS AFTERNOON BUT NOT ENOUGH
CONFIDENCE TO MENTION AT ANY OF THE TAF SITES AT THIS TIME. MODEL
DATA SEEMS TO INDICATE THAT BULK OF CONVECTION THAT MAY DEVELOP
LATER THIS AFTERNOON MAY BE EAST OF THE TAF SITES. SOME MVFR FOG MAY
DEVELOP EARLY WEDNESDAY MORNING TOWARDS THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
000
FXUS62 KCAE 212145
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
545 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
SATELLITE AND RADAR TRENDS AT 2145Z INDICATE SCATTERED THUNDERSTORM
FOCUS NOW IN THE CSRA EARLY THIS EVENING. POPS DECREASING TO THE
NORTH ACROSS THE MIDLANDS. THUNDERSTORMS SHOULD DIMINISH DURING
THE NEXT COUPLE OF HOURS.
OVERNIGHT...WHICH SHOULD AID IN AT LEAST SOME PATCHY FOG
FORMATION LATE TONIGHT. LOWS WILL FALL INTO THE MIDDLE 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WEDNESDAY AND WEDNESDAY NIGHT...LOW PRESSURE WILL CONTINUE MOVING
THROUGH THE CENTRAL GREAT LAKES WITH HIGH PRESSURE OFF THE MID
ATLANTIC COAST. THIS WILL CONTINUE THE SOUTHERLY WINDS AND
MOISTURE ADVECTION INTO THE AREA ALONG WITH INSTABILITY. RESULT
WILL BE ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION WITH THE
GREATEST POTENTIAL ACROSS THE EASTERN MIDLANDS. WITH PWAT VALUES
REMAINING IN THE 1.6 TO 1.7 INCH RANGE THE POSSIBILITY OF HEAVY
RAINFALL WILL BE THE MAIN THREAT CAUSING STANDING WATER IN LOW
LYING AND POOR DRAINAGE AREAS. WITH THE UPPER TROUGH MOVING AWAY
FROM THE AREA AND UPPER HEIGHTS RISING SLIGHTLY TEMPERATURES WILL
BE SLIGHTLY HIGHER WITH MID 80S FOR MOST LOCATIONS. CONVECTION
WILL DIMINISH WITH SUNSET...HOWEVER WITH THE COLD FRONT
APPROACHING FROM THE WEST THERE IS SOME POTENTIAL FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT MAINLY OVER THE WESTERN MIDLANDS.
OVERNIGHT LOWS WILL GENERALLY BE IN THE MID 60S.
THURSDAY AND THURSDAY NIGHT...THURSDAY WILL SEE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT CROSSES THE REGION.
ALTHOUGH MODELS DIFFER SLIGHTLY ON TIMING OF FROPA INDICATIONS ARE
FOR LATE MORNING TO EARLY AFTERNOON. THIS WILL ALLOW THE BEST
HEATING OVER THE EASTERN MIDLANDS ALONG WITH THE BEST CHANCE OF
CONVECTION. PWAT VALUES WILL AGAIN BE IN EXCESS OF 1.6 INCHES
CONTINUING THE THREAT FOR HEAVY RAIN. THE FRONT WILL MOVE OFFSHORE
DURING THE AFTERNOON HOURS WITH THE CHANCES OF SHOWERS DIMINISHING
RAPIDLY THROUGH THE EVENING HOURS AS DRIER AIR BEGINS TO PUSH INTO
THE FORECAST AREA. DAYTIME HIGHS WILL BE IN THE MID 80S WITH
OVERNIGHT LOWS IN THE MID 60S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
LOCATION DIFFERENCES APPEARING FOR SUNDAY INTO TUESDAY. PATTERN
WILL REMAIN ACTIVE AS HIGH PRESSURE AND DRIER AIR MOVE INTO THE
AREA ON FRIDAY AND FRIDAY NIGHT. ON SATURDAY AFTERNOON THE HIGH
WILL SLIDE SO THE SOUTHEAST AS THE NEXT LOW PRESSURE SYSTEM SLOWLY
TRIES TO DEVELOP OVER THE CENTRAL US. THIS WILL PUSH A FRONTAL
BOUNDARY TOWARD THE REGION ON SUNDAY...WITH THE GFS KEEPING THE
FRONT FURTHER NORTH AND THE ECMWF HAVING THE FRONT ALONG THE NC/SC
BORDER. BY MONDAY THE GFS HAS PUSHED THE FRONT INTO SOUTHERN NC
WITH THE ECMWF OVER THE NORTHERN MIDLANDS. HAVE GONE WITH A
COMPROMISE OF THE ECMWF AND GFS FOR THE LATTER HALF OF THE LONG
TERM WHICH CURRENTLY KEEPS THE AREA RAIN FREE THROUGH THE END OF
THE LONG TERM...HOWEVER CONFIDENCE IS LOW FOR SUNDAY THROUGH
TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
ENHANCE CU FIELD IN NORTH/SOUTH MOISTURE BAND SITUATED CLOSE TO
ALL TAF SITES THIS AFTERNOON WILL HELP AID IN ISOLATED AND
SCATTERED SHOWER/STORM DEVELOPMENT THROUGH THE AFTERNOON AND EARLY
EVENING HOURS. CONFIDENCE NOT ENOUGH TO PUT IN ANY TAFS AT THIS
TIME. WOULD LOOK LIKE THE BEST CHANCE FOR ANY ACTIVITY WOULD FALL
ACROSS THE CAE/CUB/OGB SITES...WITH SLIGHTLY LOWER CHANCES AT AGS/DNL.
SCATTERED TO BROKEN CLOUDS AROUND 3KFT SHOULD DIMINISH AFTER
SUNSET...WITH MOSTLY SCATTERED CLOUDS THROUGH MIDNIGHT. LATE
TONIGHT...LOW-LEVEL MOISTURE WILL REMAIN HIGH. BUFKIT SOUNDINGS
INDICATE THAT A LOW-LEVEL JET AROUND 20 KNOTS WILL SETUP ACROSS THE
TAF SITES...WHICH SHOULD HELP LIMIT ANY WIDESPREAD FOG FORMATION.
SHOULD SEE SOME SCATTERED LOW CLOUDS DEVELOP ONCE AGAIN TOWARDS
MORNING...AND WOULD NOT BE SURPRISED TO SEE A STRATUS DECK DEVELOP
AT SUNRISE. WILL HINT AT THAT IN TAFS WITH LOW SCATTERED CLOUDS.
LATER SHIFTS SHOULD BE ABLE TO ANALYZE THE LOW STRATUS/FOG
POTENTIAL BETTER.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFTERNOON AND EVENING...POSSIBLE THROUGH FRIDAY. LATE NIGHT/EARLY
MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
000
FXUS62 KCAE 211958
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
358 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THIS AFTERNOON...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL CONTINUE ACROSS THE AREA. BEST MOISTURE IS SITUATED IN A
NORTH/SOUTH BAND ACROSS THE CENTER OF THE FORECAST AREA...AND THAT
IS WHERE SATELLITE INDICATES TOWERING CU FIELD AND RADAR INDICATES
SOME SHOWER DEVELOPMENT. CONVERGENCE ASSOCIATED WITH THE SEA-
BREEZE FRONT SHOULD ALSO AID COVERAGE IN THE EAST PART LATE THIS
AFTERNOON.
TONIGHT...EXPECTING SHOWER ACTIVITY TO DIMINISH BEFORE MIDNIGHT.
PLENTY OF LOW-LEVEL MOISTURE WILL REMAIN ACROSS THE REGION
OVERNIGHT...WHICH SHOULD AID IN AT LEAST SOME PATCHY FOG FORMATION
LATE TONIGHT. LOWS WILL FALL INTO THE MIDDLE 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WEDNESDAY AND WEDNESDAY NIGHT...LOW PRESSURE WILL CONTINUE MOVING
THROUGH THE CENTRAL GREAT LAKES WITH HIGH PRESSURE OFF THE MID
ATLANTIC COAST. THIS WILL CONTINUE THE SOUTHERLY WINDS AND
MOISTURE ADVECTION INTO THE AREA ALONG WITH INSTABILITY. RESULT
WILL BE ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION WITH THE
GREATEST POTENTIAL ACROSS THE EASTERN MIDLANDS. WITH PWAT VALUES
REMAINING IN THE 1.6 TO 1.7 INCH RANGE THE POSSIBILITY OF HEAVY
RAINFALL WILL BE THE MAIN THREAT CAUSING STANDING WATER IN LOW
LYING AND POOR DRAINAGE AREAS. WITH THE UPPER TROUGH MOVING AWAY
FROM THE AREA AND UPPER HEIGHTS RISING SLIGHTLY TEMPERATURES WILL
BE SLIGHTLY HIGHER WITH MID 80S FOR MOST LOCATIONS. CONVECTION
WILL DIMINISH WITH SUNSET...HOWEVER WITH THE COLD FRONT
APPROACHING FROM THE WEST THERE IS SOME POTENTIAL FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT MAINLY OVER THE WESTERN MIDLANDS.
OVERNIGHT LOWS WILL GENERALLY BE IN THE MID 60S.
THURSDAY AND THURSDAY NIGHT...THURSDAY WILL SEE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT CROSSES THE REGION.
ALTHOUGH MODELS DIFFER SLIGHTLY ON TIMING OF FROPA INDICATIONS ARE
FOR LATE MORNING TO EARLY AFTERNOON. THIS WILL ALLOW THE BEST
HEATING OVER THE EASTERN MIDLANDS ALONG WITH THE BEST CHANCE OF
CONVECTION. PWAT VALUES WILL AGAIN BE IN EXCESS OF 1.6 INCHES
CONTINUING THE THREAT FOR HEAVY RAIN. THE FRONT WILL MOVE OFFSHORE
DURING THE AFTERNOON HOURS WITH THE CHANCES OF SHOWERS DIMINISHING
RAPIDLY THROUGH THE EVENING HOURS AS DRIER AIR BEGINS TO PUSH INTO
THE FORECAST AREA. DAYTIME HIGHS WILL BE IN THE MID 80S WITH
OVERNIGHT LOWS IN THE MID 60S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
LOCATION DIFFERENCES APPEARING FOR SUNDAY INTO TUESDAY. PATTERN
WILL REMAIN ACTIVE AS HIGH PRESSURE AND DRIER AIR MOVE INTO THE
AREA ON FRIDAY AND FRIDAY NIGHT. ON SATURDAY AFTERNOON THE HIGH
WILL SLIDE SO THE SOUTHEAST AS THE NEXT LOW PRESSURE SYSTEM SLOWLY
TRIES TO DEVELOP OVER THE CENTRAL US. THIS WILL PUSH A FRONTAL
BOUNDARY TOWARD THE REGION ON SUNDAY...WITH THE GFS KEEPING THE
FRONT FURTHER NORTH AND THE ECMWF HAVING THE FRONT ALONG THE NC/SC
BORDER. BY MONDAY THE GFS HAS PUSHED THE FRONT INTO SOUTHERN NC
WITH THE ECMWF OVER THE NORTHERN MIDLANDS. HAVE GONE WITH A
COMPROMISE OF THE ECMWF AND GFS FOR THE LATTER HALF OF THE LONG
TERM WHICH CURRENTLY KEEPS THE AREA RAIN FREE THROUGH THE END OF
THE LONG TERM...HOWEVER CONFIDENCE IS LOW FOR SUNDAY THROUGH
TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
ENHANCE CU FIELD IN NORTH/SOUTH MOISTURE BAND SITUATED CLOSE TO
ALL TAF SITES THIS AFTERNOON WILL HELP AID IN ISOLATED AND
SCATTERED SHOWER/STORM DEVELOPMENT THROUGH THE AFTERNOON AND EARLY
EVENING HOURS. CONFIDENCE NOT ENOUGH TO PUT IN ANY TAFS AT THIS
TIME. WOULD LOOK LIKE THE BEST CHANCE FOR ANY ACTIVITY WOULD FALL
ACROSS THE CAE/CUB/OGB SITES...WITH SLIGHTLY LOWER CHANCES AT AGS/DNL.
SCATTERED TO BROKEN CLOUDS AROUND 3KFT SHOULD DIMINISH AFTER
SUNSET...WITH MOSTLY SCATTERED CLOUDS THROUGH MIDNIGHT. LATE
TONIGHT...LOW-LEVEL MOISTURE WILL REMAIN HIGH. BUFKIT SOUNDINGS
INDICATE THAT A LOW-LEVEL JET AROUND 20 KNOTS WILL SETUP ACROSS THE
TAF SITES...WHICH SHOULD HELP LIMIT ANY WIDESPREAD FOG FORMATION.
SHOULD SEE SOME SCATTERED LOW CLOUDS DEVELOP ONCE AGAIN TOWARDS
MORNING...AND WOULD NOT BE SURPRISED TO SEE A STRATUS DECK DEVELOP
AT SUNRISE. WILL HINT AT THAT IN TAFS WITH LOW SCATTERED CLOUDS.
LATER SHIFTS SHOULD BE ABLE TO ANALYZE THE LOW STRATUS/FOG
POTENTIAL BETTER.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFTERNOON AND EVENING...POSSIBLE THROUGH FRIDAY. LATE NIGHT/EARLY
MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
000
FXUS62 KCHS 211954
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
354 PM EDT TUE MAY 21 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A
COLD FRONT WILL MOVE THROUGH THE AREA ON FRIDAY WITH DRY HIGH
PRESSURE BUILDING IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
GENERALLY ALONG AND WEST OF INTERSTATE 95 BY LATE
AFTERNOON...WHILE THE PERSISTENT CONVECTION OVER THE CHARLESTON
TRI COUNTY AREA HAS STEADILY DISSIPATED INTO LIGHT SHOWERS.
EARLIER HEAVY RAIN AND THUNDERSTORMS WORKED OVER THE ENVIRONMENT
NORTH OF BEAUFORT COUNTY FAIRLY WELL...AND LATEST THINKING IS
THAT STRONGEST CONVECTION WILL REMAIN WEST AND SOUTH OF THE TRI
COUNTY. NORTH/NORTHWEST LOW TO MID LEVEL FLOW WILL CONTINUE TO
STEER STORMS FARTHER SOUTH AS THE AFTERNOON PROGRESSES.
MESOANALYSIS REVEALS THAT BEST INSTABILITY STILL PERSISTS ACROSS
THE SOUTHWEST PORTION OF THE FORECAST AREA...AND WILL THUS NEED TO
MONITOR ONGOING CONVECTION ACROSS INLAND AREAS FOR BRIEF
INTENSIFICATION...ESPECIALLY WHERE MESOSCALE BOUNDARY INTERACTIONS
OCCUR. THE OVERALL SEVERE WEATHER POTENTIAL IS LOW CONSIDERING
THAT BEST LAPSE RATES ARE CONFINED WEST OF THE AREA AND THE WIND
PROFILE IS RATHER WEAK. HOWEVER...AN ISOLATED SEVERE THUNDERSTORM
CANNOT BE RULED OUT WHERE BOUNDARIES MERGE WITHIN THE MORE
UNSTABLE AIR WEST OF INTERSTATE 95. OTHERWISE...HEAVY RAIN DUE TO
SLOW STORM MOTIONS STILL SEEMS TO BE THE MAIN HAZARD INTO EARLY
EVENING.
THUNDERSTORM ACTIVITY IS EXPECTED TO GRADUALLY DISSIPATE AND
BECOME FURTHER CONFINED TO THE WESTERN ZONES WITHIN WANING
HEATING/INSTABILITY AROUND SUNSET. HAVE MAINTAINED A SLIGHT
CHANCE OF RAIN MOST AREAS BY AROUND 00Z...WITH RAIN POTENTIAL
DIMINISHING FROM EAST TO WEST LATER IN THE EVENING INTO THE
OVERNIGHT PERIOD. THE MEANDERING BAGGY UPPER TROUGH WILL STEADILY
WEAKEN AND BECOME ABSORBED INTO A LARGER TROUGH TO THE WEST
THROUGH THE PERIOD. CONSIDERING SOME SHORTWAVE ENERGY WILL LINGER
OVER THE AREA TO MAINTAIN A RIBBON OF DEEP MOISTURE...ONSHORE FLOW
ON THE PERIPHERY OF THE ATLANTIC SURFACE HIGH COULD ALLOW ISOLATED
MARINE SHOWERS TO PUSH LOCALLY ONSHORE AFTER MIDNIGHT.
FOG POTENTIAL IS A BIT DIFFICULT TO DETERMINE...AS MUCH DEPENDS ON
THE PERSISTENCE AND LOCATION OF ANY CLOUD COVER OVERNIGHT. SREF
AND NAM MODEL SOLUTIONS DO NOT INDICATE SIGNIFICANT FOG FORMATION
DESPITE WET SOIL WHERE RAIN OCCURRED THIS AFTERNOON. WILL KEEP
MENTION OF FOG OUT OF THE FORECAST AT THIS POINT AND ALLOW
SUBSEQUENT FORECAST UPDATES TO REASSESS THE ENVIRONMENT LATER THIS
EVENING. EXPECT LOW TEMPERATURES TO RANGE FROM THE MID 60S TO NEAR
70 ALONG THE COAST.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY AND THURSDAY WITH
BROAD UPPER TROUGHING INLAND AND HIGH PRESSURE OVER THE ATLANTIC.
THIS PATTERN WILL MAINTAIN DEEP MOISTURE OVER THE AREA WITH DECENT
RAIN CHANCES THROUGH THE PERIOD...MOSTLY CONFINED INLAND DURING THE
DAY AND OVER THE ATLANTIC AT NIGHT. THE RISK FOR SEVERE WEATHER
APPEARS LOW GIVEN THE LACK OF ORGANIZATION POTENTIAL...ALTHOUGH
HEAVY RAINFALL COULD RESULT IN LOCALIZED FLOODING. HIGH/LOW
TEMPERATURES WILL ULTIMATELY DEPEND ON CLOUD COVER/RAINFALL BUT
GENERALLY SHOULD BE CLOSE TO SLIGHTLY ABOVE NORMAL.
A COLD FRONT SHOULD PUSH THROUGH FRIDAY MORNING...ALTHOUGH THE
NORTHWEST DOWNSLOPE FLOW WILL HELP TO OFFSET THE COLD ADVECTION.
THIS SHOULD LEAD TO TEMPERATURES CLOSE TO NORMAL IN THE MID 80S. THE
BIGGER CHANGE WILL BE THE DRIER AIR WHICH WILL MAKE IT FEEL A LOT
MORE COMFORTABLE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP NEAR THE
TERMINALS THROUGH THE AFTERNOON...WITH REDUCED VSBYS AND CIGS
LIKELY WITHIN HEAVIER RAINFALL. AMENDMENTS WILL LIKELY BE NEEDED
TO ACCOUNT FOR RADAR TRENDS DURING THE NEXT SEVERAL HOURS...WITH
MOST THUNDERSTORM ACTIVITY DIMINISHING AFTER SUNSET. GIVEN PRIOR
RAINFALL AND LIGHT WINDS...MVFR OR LOWER CIGS/VSBYS WILL BE
POSSIBLE OVERNIGHT. HOWEVER...DUE TO LOW CONFIDENCE IN TIMING AND
DURATION...HAVE OPTED TO NOT INCLUDE MENTION IN THE TAFS AT THIS
TIME AND ALLOW SUBSEQUENT ISSUANCES TO ADDRESS THIS POTENTIAL.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
TONIGHT...THE OFFSHORE RIDGE OF HIGH PRESSURE WILL CONTINUE TO
EXTEND WEST ACROSS THE COASTAL WATERS...SUPPORTING SOUTHEAST TO
SOUTH WINDS LESS THAN 15 KT AND SEAS IN THE 2 TO 4 FT
RANGE...HIGHEST OVER OUTER GEORGIA WATERS BEYOND 20 NM.
WEDNESDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES THROUGH FRIDAY. THE
MUCH COOLER AND DRIER AIR MASS BEHIND THE FRONT WILL MOVE IN AND
LEAD TO INCREASING WINDS AND BUILDING SEAS...POSSIBLY REACHING
ADVISORY LEVELS...AT LEAST ACROSS THE WATERS BEYOND 20 NM.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AS WELL AS MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE BUT MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...RJB
LONG TERM...JRL
AVIATION...ECT/RJB
MARINE...RJB/WMS
000
FXUS62 KFFC 211914
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
314 PM EDT TUE MAY 21 2013
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MODELS CONTINUE IN GOOD AGREEMENT THROUGH THE SHORT TERM. AIRMASS
SHOWERS/TSTORMS DEVELOPING ACROSS THE CWA...MAINLY ACROSS THE
EXTREME NORTH AND EASTERN PARTS OF THE CWA. THESE WILL DISSIPATE
SHORTLY AFTER SUNSET THIS EVENING. THERE IS A POSSIBILITY THAT THE
STORMS OVER NORTHWEST AL AND CENTRAL TN COULD MAKE IT TO EXTREME
NORTHWEST GA BEFORE DIMINISHING THIS EVENING. THE H5 RIDGE OVER THE
EASTERN U.S. WILL WEAKEN AS THE CENTRAL U.S. TROUGH MOVES INTO THE
MISSISSIPPI VALLEY. THIS WILL PUSH A COLD FRONT INTO THE TENNESSEE
VALLEY WEDNESDAY WHICH WILL BRING A BETTER CHANCE OF THUNDERSTORMS
TO THE CWA...MAINLY ACROSS NORTH GA. INSTABILITY INCREASES WEDNESDAY
ACROSS NORTH GA AND THIS COULD PRODUCE A FEW STRONG STORMS. GUIDANCE
TEMPS LOOK GOOD FOR TONIGHT...ALTHOUGH TRICKY FOR WEDNESDAY WITH
ADDITIONAL CLOUDS. WILL TREND TO THE COOLER SIDE OF GUIDANCE ACROSS
NORTH GA FOR HIGHS ON WEDNESDAY DUE TO INCREASED CLOUDS AND PRECIP.
17
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
BY WEDNESDAY EVENING...BOTH THE GFS AND ECMWF INDICATE THAT THE
FRONT WILL BE WEAKENING SIGNIFICANTLY. GFS REMAINS AB IT ON THE
STRONG SIDE WITH A SLIGHTLY MORE EAST WITH THE GREAT LAKES SURFACE
LOW. BOTH ARE TRANSITIONING THE UPPER LOW TO MORE OF A SHARP OPEN
TROUGH PHASING WITH THE LONGWAVE TROUGH IN CANADA. WEAK SHORTWAVE
OFF THE SOUTH CAROLINA COAST WILL LIFT NORTHEAST AND BE ABSORBED
BY THE LONGWAVE TROUGH AS WELL. SPC CONTINUES THE AREA IN GENERAL
THUNDER FOR THURSDAY...WITH MUCAPE VALUES 500-1000 J/KG EARLY IN
THE DAY...DECREASING BY MID-MORNING...AND INCREASING AGAIN IN
EXTREME SOUTHERN ZONES JUST AHEAD OF THE FRONT AFTER 18Z TO OVER
1000 J/KG. WILL HAVE TO MONITOR THE AREA FOR THE POTENTIAL FOR
ISOLATED STRONG STORMS BUT NOTHING TO SIGNIFICANT.
COLD FRONT SHOULD BE PUSHED THROUGH THE AREA BY LATE THURSDAY...
AND HAVE DECREASED TEMPS NORTHWEST SOMEWHAT TO LINE UP WITH THAT
TIMING A LITTLE BETTER. SHOULD SEE A SIGNIFICANT DECREASE IN TEMPS
TOWARD THE END OF THE WEEK WITH SURFACE HIGH PRESSURE BUILDING IN
AND NORTHWEST FLOW ALOFT...CURRENT FORECAST HAS HIGHS ON FRIDAY
ABOUT 5 DEGREES COOLER THAN HIGHS ON THURSDAY EXCEPT IN CENTRAL
GEORGIA. SEE PREVIOUS LONG TERM DISCUSSION BELOW.
TDP
PREV DISCUSSION...
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 351 AM EDT TUE MAY 21 2013/
WEAK COLD FRONT APPROACHING WITH AN UPPER LEVEL TROUGH/SHORT WAVE
FORECAST TO MOVE INTO THE AREA WEDNESDAY NIGHT AND WITH ASSOCIATED
MOISTURE AND INSTABILITY...SCATTERED SHOWERS AND THUNDERSTORMS
ARE REASONABLE...MOST SO FOR THE EVENING HOURS. THE WEAK COLD
FRONT MOVES INTO THE AREA ON THURSDAY. IT IS UNCLEAR HOW MUCH
CONVECTION WILL BE ASSOCIATED WITH THE FRONT. THE BEST INSTABILITY
IS FORECAST OVER CENTRAL GA WITH THE BEST UPPER SUPPORT OVER N GA.
AT THIS TIME IT SEEMS REASONABLE THAT THERE WILL BE A CHANCE OF
SHOWERS AND THUNDERSTORMS...MOST SO IN THE AFTERNOON. THE MAIN
UPPER TROUGH MOVES E FOR FRIDAY WITH A DRIER AIRMASS MOVING OVER
THE AREA BEHIND THE FRONT AS SURFACE HIGH PRESSURE BUILDS ALONG
WITH A MUCH DRIER NW FLOW. DRY CONDITIONS CONTINUE SATURDAY AS
HIGH PRESSURE MOVES ACROSS THE EASTERN STATES. SUNDAY LOOKS TO BE
MAINLY DRY AS WELL EXCEPT THE NW FLOW ALOFT BEGINS TO BECOME MORE
ACTIVE TO THE N WITH SOME MOISTURE SKIRTING BY THE AREA. MOISTURE
CONTINUES TO SKIRT BY MONDAY AND TUESDAY WITH A SHARP GRADIENT OF
SIGNIFICANT MOISTURE AT THE GA/SC LINE. FOR NOW WILL LEAVE A DRY
FORECAST FOR MONDAY/TUESDAY AND CONTINUE TO MONITOR THE PROGRESS
OF THE NW FLOW. TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF
NORMAL THROUGH THE PERIOD EXCEPT SATURDAY AND SUNDAY MORNING LOWS
RUNNING 5-10 DEGREES BELOW NORMAL.
BDL
&&
.AVIATION...
18Z UPDATE...
CU FIELD HAS DEVELOPED ACROSS THE REGION WITH BASES BETWEEN 4000 AND
5000. THESE WILL DISSIPATE SHORTLY AFTER SUNSET. REDEVELOPMENT OF A
STRATO-CU DECK WEDNESDAY MORNING WITH 3500 TO 5000 FT CIGS SPREADING
ACROSS THE REGION FROM NORTHWEST TO SOUTHEAST. BY 18Z MOST AREAS
WILL SEE CIGS AROUND 4000 TO 5000 FT. WINDS WILL BE NEAR CALM TO
LIGHT WESTERLY THIS AFTERNOON...CALM TONIGHT...THEN SOUTHWEST 10KTS
OR LESS WEDNESDAY. ISOLATED SHOWERS DEVELOPING ACROSS EXTREME NORTH
GA. SHOULD CONTINUE TO SEE SCATTERED SHOWERS/TSTORMS DEVELOP THIS
AFTERNOON IN THIS AREA WITH THE CELLS MOVING NORTHEAST. OTHER
SHOWERS DEVELOPING OVER WESTERN SC MOVING SOUTHWEST AND THIS WILL
ALSO CONTINUE THIS AFTERNOON. CONVECTION WILL DISSIPATE THIS EVENING
WITH REDEVELOPMENT...MAINLY WEDNESDAY AFTERNOON AND MAINLY ACROSS
NORTH GEORGIA AS THE COLD FRONT GETS CLOSER.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON AREA OF CONVECTION THIS AFTERNOON.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 84 64 84 / 30 40 40 30
ATLANTA 67 83 66 82 / 20 40 40 30
BLAIRSVILLE 60 77 60 78 / 30 60 50 30
CARTERSVILLE 64 84 62 82 / 20 60 40 30
COLUMBUS 68 89 67 87 / 20 30 30 30
GAINESVILLE 65 83 64 81 / 20 50 40 30
MACON 63 87 65 86 / 20 30 30 30
ROME 64 84 61 83 / 30 60 40 30
PEACHTREE CITY 63 85 63 84 / 20 40 30 30
VIDALIA 68 89 69 88 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...17
LONG TERM....TDP
AVIATION...17
000
FXUS62 KCAE 211842
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
242 PM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...EXPECTING ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TO CONTINUE TO DEVELOP ACROSS THE AREA. BEST
MOISTURE IS SITUATED IN A NORTH/SOUTH BAND ACROSS THE CENTER OF
THE FORECAST AREA...AND THAT IS WHERE SATELLITE INDICATES TOWERING
CU FIELD AND RADAR INDICATES SOME SHOWER DEVELOPMENT. CONVERGENCE
ASSOCIATED WITH THE SEA-BREEZE FRONT SHOULD ALSO AID COVERAGE IN
THE EAST PART LATE THIS AFTERNOON.
TONIGHT...EXPECTING SHOWER ACTIVITY TO DIMINISH BEFORE MIDNIGHT.
PLENTY OF LOW-LEVEL MOISTURE WILL REMAIN ACROSS THE REGION
OVERNIGHT...WHICH SHOULD AID IN AT LEAST SOME PATCHY FOG FORMATION
LATE TONIGHT. LOWS WILL FALL INTO THE MIDDLE 60S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
WEDNESDAY AND WEDNESDAY NIGHT...LOW PRESSURE WILL CONTINUE MOVING
THROUGH THE CENTRAL GREAT LAKES WITH HIGH PRESSURE OFF THE MID
ATLANTIC COAST. THIS WILL CONTINUE THE SOUTHERLY WINDS AND
MOISTURE ADVECTION INTO THE AREA ALONG WITH INSTABILITY. RESULT
WILL BE ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION WITH THE
GREATEST POTENTIAL ACROSS THE EASTERN MIDLANDS. WITH PWAT VALUES
REMAINING IN THE 1.6 TO 1.7 INCH RANGE THE POSSIBILITY OF HEAVY
RAINFALL WILL BE THE MAIN THREAT CAUSING STANDING WATER IN LOW
LYING AND POOR DRAINAGE AREAS. WITH THE UPPER TROUGH MOVING AWAY
FROM THE AREA AND UPPER HEIGHTS RISING SLIGHTLY TEMPERATURES WILL
BE SLIGHTLY HIGHER WITH MID 80S FOR MOST LOCATIONS. CONVECTION
WILL DIMINISH WITH SUNSET...HOWEVER WITH THE COLD FRONT
APPROACHING FROM THE WEST THERE IS SOME POTENTIAL FOR SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT MAINLY OVER THE WESTERN MIDLANDS.
OVERNIGHT LOWS WILL GENERALLY BE IN THE MID 60S.
THURSDAY AND THURSDAY NIGHT...THURSDAY WILL SEE ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT CROSSES THE REGION.
ALTHOUGH MODELS DIFFER SLIGHTLY ON TIMING OF FROPA INDICATIONS ARE
FOR LATE MORNING TO EARLY AFTERNOON. THIS WILL ALLOW THE BEST
HEATING OVER THE EASTERN MIDLANDS ALONG WITH THE BEST CHANCE OF
CONVECTION. PWAT VALUES WILL AGAIN BE IN EXCESS OF 1.6 INCHES
CONTINUING THE THREAT FOR HEAVY RAIN. THE FRONT WILL MOVE OFFSHORE
DURING THE AFTERNOON HOURS WITH THE CHANCES OF SHOWERS DIMINISHING
RAPIDLY THROUGH THE EVENING HOURS AS DRIER AIR BEGINS TO PUSH INTO
THE FORECAST AREA. DAYTIME HIGHS WILL BE IN THE MID 80S WITH
OVERNIGHT LOWS IN THE MID 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE LONG TERM WITH SOME
LOCATION DIFFERENCES APPEARING FOR SUNDAY INTO TUESDAY. PATTERN
WILL REMAIN ACTIVE AS HIGH PRESSURE AND DRIER AIR MOVE INTO THE
AREA ON FRIDAY AND FRIDAY NIGHT. ON SATURDAY AFTERNOON THE HIGH
WILL SLIDE SO THE SOUTHEAST AS THE NEXT LOW PRESSURE SYSTEM SLOWLY
TRIES TO DEVELOP OVER THE CENTRAL US. THIS WILL PUSH A FRONTAL
BOUNDARY TOWARD THE REGION ON SUNDAY...WITH THE GFS KEEPING THE
FRONT FURTHER NORTH AND THE ECMWF HAVING THE FRONT ALONG THE NC/SC
BORDER. BY MONDAY THE GFS HAS PUSHED THE FRONT INTO SOUTHERN NC
WITH THE ECMWF OVER THE NORTHERN MIDLANDS. HAVE GONE WITH A
COMPROMISE OF THE ECMWF AND GFS FOR THE LATTER HALF OF THE LONG
TERM WHICH CURRENTLY KEEPS THE AREA RAIN FREE THROUGH THE END OF
THE LONG TERM...HOWEVER CONFIDENCE IS LOW FOR SUNDAY THROUGH
TUESDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE NEAR NORMAL.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
ENHANCE CU FIELD IN NORTH/SOUTH MOISTURE BAND SITUATED CLOSE TO
ALL TAF SITES THIS AFTERNOON WILL HELP AID IN ISOLATED AND
SCATTERED SHOWER/STORM DEVELOPMENT THROUGH THE AFTERNOON AND EARLY
EVENING HOURS. CONFIDENCE NOT ENOUGH TO PUT IN ANY TAFS AT THIS
TIME. WOULD LOOK LIKE THE BEST CHANCE FOR ANY ACTIVITY WOULD FALL
ACROSS THE CAE/CUB/OGB SITES...WITH SLIGHTLY LOWER CHANCES AT AGS/DNL.
SCATTERED TO BROKEN CLOUDS AROUND 3KFT SHOULD DIMINISH AFTER
SUNSET...WITH MOSTLY SCATTERED CLOUDS THROUGH MIDNIGHT. LATE
TONIGHT...LOW-LEVEL MOISTURE WILL REMAIN HIGH. BUFKIT SOUNDINGS
INDICATE THAT A LOW-LEVEL JET AROUND 20 KNOTS WILL SETUP ACROSS THE
TAF SITES...WHICH SHOULD HELP LIMIT ANY WIDESPREAD FOG FORMATION.
SHOULD SEE SOME SCATTERED LOW CLOUDS DEVELOP ONCE AGAIN TOWARDS
MORNING...AND WOULD NOT BE SURPRISED TO SEE A STRATUS DECK DEVELOP
AT SUNRISE. WILL HINT AT THAT IN TAFS WITH LOW SCATTERED CLOUDS.
LATER SHIFTS SHOULD BE ABLE TO ANALYZE THE LOW STRATUS/FOG
POTENTIAL BETTER.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFTERNOON AND EVENING...POSSIBLE THROUGH FRIDAY. LATE NIGHT/EARLY
MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 211752
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
152 PM EDT TUE MAY 21 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL DROP THROUGH THE AREA ON FRIDAY WITH DRY HIGH PRESSURE BUILDING
IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO IMPACT THE
CHARLESTON TRI COUNTY REGION BY EARLY AFTERNOON...WHILE ISOLATED
TO SCATTERED CONVECTION HAS ALSO INITIATED ALONG AND INLAND OF THE
SEABREEZE FARTHER SOUTH. HAVE UPDATED FORECAST TO INCLUDE LATEST
RADAR TRENDS...INDICATING HIGHEST COVERAGE OF THUNDERSTORMS ACROSS
MUCH OF THE SOUTH CAROLINA ZONES AND GENERALLY WEST OF INTERSTATE
95 IN SOUTHEAST GEORGIA.
LATEST STORM PREDICTION CENTER MESOANALYSIS SHOWS INSTABILITY
MAXIMIZED TO THE WEST...WEAKENING CLOSER TO THE COASTLINE. AS A
RESULT...THE MAIN HAZARD ASSOCIATED WITH AFTERNOON CONVECTION HAS
BEEN HEAVY AND PERSISTENT DOWNPOURS. UPPER AIR SOUNDINGS INDICATE
LITTLE WIND IN THE LOW TO MID LEVELS...ALLOWING STORM MOTIONS TO
BE QUITE SLOW WITHIN A HIGH PRECIPITABLE WATER ENVIRONMENT. THE
POTENTIAL FOR LOCALIZED FLOODING WITHIN SLOW MOVING THUNDERSTORMS
WILL LINGER THROUGH THE AFTERNOON INTO THE EARLY EVENING...WHEN
THE MAJORITY OF THE CONVECTION WILL PUSH INLAND WITH THE SEABREEZE
AND DISSIPATE WITH WANING HEATING/INSTABILITY. ALTHOUGH THE SEVERE
THREAT LOOKS MARGINAL OVERALL DUE TO RATHER WEAK WIND FIELDS AND
BEST LAPSE RATES CONFINED WEST OF THE AREA...WILL CONTINUE TO
MONITOR THE SOUTHWEST ZONES...WHERE MORNING INSOLATION ALLOWED
FOR IMPROVED INSTABILITY. HOWEVER...IT WILL LIKELY TAKE BOUNDARY
INTERACTIONS TO SUPPORT ANY ISOLATED SEVERE STORM DEVELOPMENT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
INLAND CONVECTIVE RAIN WILL BE ENDING EARLY IN THE EVENING...AS
THE SEA BREEZE PUSHES WELL INLAND AND CONVERGENCE DIMINISHES. NO
CHANGES TO THE FORECAST TONIGHT...WITH CLOUDS GRADUALLY THINNING
AND LOW TEMPERATURES RANGING FROM 65 TO 70 DEGREES. MAY NEED TO
EVENTUALLY ADD SOME PATCHY FOG TO THE FORECAST AGAIN
TONIGHT...DEPENDENT ON TRENDS WITH CLOUD DISSIPATION.
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY INTO THURSDAY WITH
BROAD UPPER TROUGHING AND ATLANTIC HIGH PRESSURE. SOUTHERLY
LOW-LEVEL FLOW WILL MAINTAIN A FAIRLY MOIST ATMOSPHERE AND HELP PUSH
A SEABREEZE INLAND EACH DAY. THE UPPER TROUGHING WILL CREATE A
SOMEWHAT MORE FAVORABLE ENVIRONMENT FOR CONVECTION TO DEVELOP...
PRIMARILY DRIVEN BY THE SEABREEZE AND BOUNDARY INTERACTIONS. WE KEPT
POPS IN THE 20-30 PERCENT RANGE BOTH DAYS.
THE MODELS ARE NOW QUITE A BIT FASTER AND IN BETTER AGREEMENT
REGARDING A COLD FRONT PUSHING THROUGH FRIDAY MORNING. WE REMOVED
POPS ON FRIDAY AND SHOW DEWPOINTS DROPPING INTO THE UPPER 50S TO
AROUND 60 DURING THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP NEAR THE
TERMINALS THROUGH THE AFTERNOON...WITH REDUCED VSBYS AND CIGS
LIKELY WITHIN HEAVIER RAINFALL. AMENDMENTS WILL LIKELY BE NEEDED
TO ACCOUNT FOR RADAR TRENDS DURING THE NEXT SEVERAL HOURS...WITH
MOST THUNDERSTORM ACTIVITY DIMINISHING AFTER SUNSET. GIVEN PRIOR
RAINFALL AND LIGHT WINDS...MVFR OR LOWER CIGS/VSBYS WILL BE
POSSIBLE OVERNIGHT. HOWEVER...DUE TO LOW CONFIDENCE IN TIMING AND
DURATION...HAVE OPTED TO NOT INCLUDE MENTION IN THE TAFS AT THIS
TIME AND ALLOW SUBSEQUENT ISSUANCES TO ADDRESS THIS POTENTIAL.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
THROUGH TONIGHT...THE STEADY STATE SYNOPTIC PATTERN CONTINUES UNABATED.
THE OFFSHORE RIDGE OF HIGH PRESSURE EXTENDS WEST ACROSS THE
COASTAL WATERS...GENERATING SOUTHEAST AND SOUTH WINDS LESS THAN 15
KT AND SEAS IN THE 2-4 FT RANGE...HIGHEST OVER OUTER GEORGIA
WATERS BEYOND 20 NM.
HIGH PRESSURE WILL SIT OVER THE WESTERN ATLANTIC UNTIL FRIDAY WHEN A
CANADIAN HIGH DROPS SOUTHEAST. WE MAY SEE A BRIEF PERIOD OF SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT INTO SATURDAY AS THE GRADIENT
TIGHTENS AND COLD ADVECTION MIXES SOME DECENT WINDS TO THE SURFACE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...ECT
MARINE...WMS/JRL
000
FXUS62 KFFC 211726
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
126 PM EDT TUE MAY 21 2013
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
/ISSUED AT 351 AM EDT TUE MAY 21 2013/
UPPER RIDGE CONTINUES BUILDING OVER THE SOUTHEAST TODAY WITH AN
UPPER LOW NEAR SOUTHEAST GA/NORTHEAST FL. THE AIR MASS REMAINS
UNSTABLE HOWEVER WATER VAPOR SHOWS SOME DRIER AIR HAS WORKED INTO
NORTHWEST GA. HAVE KEPT A SLIGHT CHANCE/LOW CHANCE POPS MAINLY OVER
THE EASTERN HALF OF THE CWA THIS AFTERNOON AND EVENING...CLOSER TO
THE UPPER LOW AND BETTER MOISTURE. TONIGHT LOOKS LIKE A LULL BETWEEN
SYSTEMS AND HAVE ONLY INCLUDED SLIGHT CHANCE POPS ACROSS THE EXTREME
NORTH. THE GFS HINTS AT A SHORT WAVE CROSSING THE TN VALLEY
OVERNIGHT. A CLOSED UPPER LOW MOVING INTO THE GREAT LAKES REGION BY
WEDNESDAY SHOULD PUSH A FRONT INTO THE LOWER MISSISSIPPI VALLEY
TOWARD GEORGIA. THE MODELS WANT TO KEEP THE FRONT WEST OF THE CWA
DURING THE DAY...BUT AN INCREASE IN MOISTURE AND INSTABILITY SHOULD
SUPPORT BETTER CHANCES OF THUNDERSTORMS ACROSS THE CWA BY WEDNESDAY
AFTERNOON. MAV/MET TEMPERATURES ARE CLOSE AND HAVE TAKEN A
COMPROMISE.
41
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 351 AM EDT TUE MAY 21 2013/
WEAK COLD FRONT APPROACHING WITH AN UPPER LEVEL TROUGH/SHORT WAVE
FORECAST TO MOVE INTO THE AREA WEDNESDAY NIGHT AND WITH ASSOCIATED
MOISTURE AND INSTABILITY...SCATTERED SHOWERS AND THUNDERSTORMS
ARE REASONABLE...MOST SO FOR THE EVENING HOURS. THE WEAK COLD
FRONT MOVES INTO THE AREA ON THURSDAY. IT IS UNCLEAR HOW MUCH
CONVECTION WILL BE ASSOCIATED WITH THE FRONT. THE BEST INSTABILITY
IS FORECAST OVER CENTRAL GA WITH THE BEST UPPER SUPPORT OVER N GA.
AT THIS TIME IT SEEMS REASONABLE THAT THERE WILL BE A CHANCE OF
SHOWERS AND THUNDERSTORMS...MOST SO IN THE AFTERNOON. THE MAIN
UPPER TROUGH MOVES E FOR FRIDAY WITH A DRIER AIRMASS MOVING OVER
THE AREA BEHIND THE FRONT AS SURFACE HIGH PRESSURE BUILDS ALONG
WITH A MUCH DRIER NW FLOW. DRY CONDITIONS CONTINUE SATURDAY AS
HIGH PRESSURE MOVES ACROSS THE EASTERN STATES. SUNDAY LOOKS TO BE
MAINLY DRY AS WELL EXCEPT THE NW FLOW ALOFT BEGINS TO BECOME MORE
ACTIVE TO THE N WITH SOME MOISTURE SKIRTING BY THE AREA. MOISTURE
CONTINUES TO SKIRT BY MONDAY AND TUESDAY WITH A SHARP GRADIENT OF
SIGNIFICANT MOISTURE AT THE GA/SC LINE. FOR NOW WILL LEAVE A DRY
FORECAST FOR MONDAY/TUESDAY AND CONTINUE TO MONITOR THE PROGRESS
OF THE NW FLOW. TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF
NORMAL THROUGH THE PERIOD EXCEPT SATURDAY AND SUNDAY MORNING LOWS
RUNNING 5-10 DEGREES BELOW NORMAL.
BDL
&&
.AVIATION...
18Z UPDATE...
CU FIELD HAS DEVELOPED ACROSS THE REGION WITH BASES BETWEEN 4000 AND
5000. THESE WILL DISSIPATE SHORTLY AFTER SUNSET. REDEVELOPMENT OF A
STRATO-CU DECK WEDNESDAY MORNING WITH 3500 TO 5000 FT CIGS SPREADING
ACROSS THE REGION FROM NORTHWEST TO SOUTHEAST. BY 18Z MOST AREAS
WILL SEE CIGS AROUND 4000 TO 5000 FT. WINDS WILL BE NEAR CALM TO
LIGHT WESTERLY THIS AFTERNOON...CALM TONIGHT...THEN SOUTHWEST 10KTS
OR LESS WEDNESDAY. ISOLATED SHOWERS DEVELOPING ACROSS EXTREME NORTH
GA. SHOULD CONTINUE TO SEE SCATTERED SHOWERS/TSTORMS DEVELOP THIS
AFTERNOON IN THIS AREA WITH THE CELLS MOVING NORTHEAST. OTHER
SHOWERS DEVELOPING OVER WESTERN SC MOVING SOUTHWEST AND THIS WILL
ALSO CONTINUE THIS AFTERNOON. CONVECTION WILL DISSIPATE THIS EVENING
WITH REDEVELOPMENT...MAINLY WEDNESDAY AFTERNOON AND MAINLY ACROSS
NORTH GEORGIA AS THE COLD FRONT GETS CLOSER.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON AREA OF CONVECTION THIS AFTERNOON.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 64 86 64 / 30 30 40 40
ATLANTA 86 67 84 66 / 10 10 50 40
BLAIRSVILLE 82 60 81 60 / 30 30 50 50
CARTERSVILLE 86 64 85 63 / 10 10 50 40
COLUMBUS 90 68 88 68 / 10 10 30 30
GAINESVILLE 85 66 84 64 / 30 30 50 40
MACON 89 64 88 65 / 20 20 30 30
ROME 86 63 85 62 / 10 20 50 40
PEACHTREE CITY 87 61 86 63 / 10 10 50 30
VIDALIA 88 69 88 68 / 30 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....BDL
AVIATION...41
000
FXUS62 KCHS 211433
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1033 AM EDT TUE MAY 21 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL DROP THROUGH THE AREA ON FRIDAY WITH DRY HIGH PRESSURE BUILDING
IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A BAGGY UPPER TROUGH WILL CONTINUE TO LINGER ACROSS THE MID
ATLANTIC AND SOUTHEAST STATES TODAY...WHILE ATLANTIC HIGH PRESSURE
REMAINS IN CONTROL OF THE SURFACE PATTERN. DEEPEST MOISTURE
APPEARS CONCENTRATED OVER THE COASTAL WATERS AND SOUTH CAROLINA
ZONES ACCORDING TO LATEST WATER VAPOR AND IR SATELLITE IMAGERY BY
MID MORNING...SETTING UP A NOTABLE DIFFERENTIAL HEATING GRADIENT
BETWEEN THE COASTAL LOCATIONS/CHARLESTON TRI COUNTY REGION AND
MUCH OF THE GEORGIA ZONES. LIGHT TO MODERATE SHOWERS PERSIST ACROSS
THE FAVORED CHARLESTON TRI COUNTY AREA...AND ALTHOUGH COVERAGE OF
THIS ACTIVITY WILL EVENTUALLY DIMINISH TOWARD NOON...LATEST
FORECAST MODELS INDICATE CONVECTION QUICKLY INITIATING ALONG AND
INLAND OF THE SEABREEZE WITHIN THE SAME PERIOD. AS WITH THE
PREVIOUS DAYS...EXPECT MOST OF THE AFTERNOON THUNDERSTORMS TO BE
CONCENTRATED ALONG THE SEABREEZE AND PUSH WEST WITH ITS INLAND
PROGRESSION.
LATEST STORM PREDICTION CENTER MESOANALYSIS SHOWS INSTABILITY
STEADILY INCREASING ACROSS THE INLAND GEORGIA ZONES...WHERE CLEAR
SKIES FOR MUCH OF THE MORNING HAS SUPPORTED BETTER INSOLATION AND
SURFACE HEATING. ALTHOUGH THE SEVERE THREAT LOOKS MARGINAL OVERALL
DUE TO RATHER WEAK WIND FIELDS AND BEST LAPSE RATES CONFINED WEST
OF THE AREA...THESE SOUTHWEST ZONES WILL NEED TO BE MONITORED FOR
ISOLATED SEVERE THUNDERSTORMS LATER TODAY WITHIN ENHANCED
INSTABILITY...ESPECIALLY CONSIDERING BOUNDARY INTERACTIONS AND
EFFECTS OF THE MORNING DIFFERENTIAL HEATING GRADIENT.
OTHERWISE...LOCALIZED DOWNPOURS AND SOME LIGHTNING WILL BE THE
MAIN IMPACTS FROM THE MAJORITY OF STORMS.
HAVE MADE ONLY MINOR CHANGES TO THE FORECAST DETAILS TO ADJUST FOR
HOURLY TRENDS. WILL ADVERTISE TEMPERATURES PEAKING IN THE MID 80S
CHARLESTON TRI COUNTY REGION TO THE UPPER 80S SOUTH OF THE
SAVANNAH RIVER...EXCEPT FOR COASTAL LOCATIONS WHERE TEMPERATURES
WILL REMAIN SUPPRESSED IN THE LOWER 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
INLAND CONVECTIVE RAIN WILL BE ENDING EARLY IN THE EVENING...AS
THE SEA BREEZE PUSHES WELL INLAND AND CONVERGENCE DIMINISHES. NO
CHANGES TO THE FORECAST TONIGHT...WITH CLOUDS GRADUALLY THINNING
AND LOW TEMPERATURES RANGING FROM 65 TO 70 DEGREES. MAY NEED TO
EVENTUALLY ADD SOME PATCHY FOG TO THE FORECAST AGAIN
TONIGHT...DEPENDENT ON TRENDS WITH CLOUD DISSIPATION.
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY INTO THURSDAY WITH
BROAD UPPER TROUGHING AND ATLANTIC HIGH PRESSURE. SOUTHERLY
LOW-LEVEL FLOW WILL MAINTAIN A FAIRLY MOIST ATMOSPHERE AND HELP PUSH
A SEABREEZE INLAND EACH DAY. THE UPPER TROUGHING WILL CREATE A
SOMEWHAT MORE FAVORABLE ENVIRONMENT FOR CONVECTION TO DEVELOP...
PRIMARILY DRIVEN BY THE SEABREEZE AND BOUNDARY INTERACTIONS. WE KEPT
POPS IN THE 20-30 PERCENT RANGE BOTH DAYS.
THE MODELS ARE NOW QUITE A BIT FASTER AND IN BETTER AGREEMENT
REGARDING A COLD FRONT PUSHING THROUGH FRIDAY MORNING. WE REMOVED
POPS ON FRIDAY AND SHOW DEWPOINTS DROPPING INTO THE UPPER 50S TO
AROUND 60 DURING THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
KCHS...ISOLATED SHOWERS LINGER IN THE VICINITY OF THE TERMINAL BY
MID MORNING...WHILE CEILINGS GENERALLY REMAIN VFR. ADDITIONAL
SHOWERS/THUNDERSTORMS ARE LIKELY WITH THE SEABREEZE THIS
AFTERNOON...YET SHOULD EVENTUALLY PUSH WEST OF KCHS BY LATER IN
THE DAY. BRIEF REDUCTIONS TO MVFR WITHIN ANY CONVECTION IS
POSSIBLE...HOWEVER PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH
TONIGHT. WILL STILL NEED TO MONITOR TRENDS FOR POTENTIAL LATE
NIGHT LOW CLOUDS AND PATCHY FOG DUE TO WET SOILS AND LIGHT WINDS.
KSAV...A FEW SHOWERS COULD DEVELOP WITH THE INITIATION OF THE SEA
BREEZE BY EARLY AFTERNOON. THE BEST CHANCES FOR SHOWERS/TSTMS WILL
BE WITH AFTERNOON CONVECTION THAT COULD BE MOVING SOUTHWEST ALONG
OR JUST WEST OF INTERSTATE 95. MAINLY VFR CONDITIONS THROUGH
TONIGHT OUTSIDE OF ANY ISOLATED CONVECTION...YET CANNOT RULE OUT
THE POTENTIAL FOR LATE NIGHT MVFR/IFR CEILINGS AND POSSIBLY LIGHT
FOG...ESPECIALLY IF SKIES CLEAR.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
THROUGH TONIGHT...THE STEADY STATE SYNOPTIC PATTERN CONTINUES UNABATED.
THE OFFSHORE RIDGE OF HIGH PRESSURE EXTENDS WEST ACROSS THE
COASTAL WATERS...GENERATING SOUTHEAST AND SOUTH WINDS LESS THAN 15
KT AND SEAS IN THE 2-4 FT RANGE...HIGHEST OVER OUTER GEORGIA
WATERS BEYOND 20 NM.
HIGH PRESSURE WILL SIT OVER THE WESTERN ATLANTIC UNTIL FRIDAY WHEN A
CANADIAN HIGH DROPS SOUTHEAST. WE MAY SEE A BRIEF PERIOD OF SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT INTO SATURDAY AS THE GRADIENT
TIGHTENS AND COLD ADVECTION MIXES SOME DECENT WINDS TO THE SURFACE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...WMS/JRL
MARINE...JRL
000
FXUS62 KCAE 211151
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
751 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /TODAY/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC
WILL DOMINATE TODAY. A MOIST SOUTH FLOW IS ASSOCIATED WITH THIS
FEATURE. STRATUS AND FOG EXPECTED TO BURN OFF ACROSS CENTRAL AND
WESTERN AREAS LATER IN THE MORNING. A MID-LEVEL SHORTWAVE TROUGH
WILL SUPPORT SHOWERS AND THUNDERSTORMS IN THE EXTREME NORTHEAST
PART EARLY THIS MORNING. THE MOISTURE PLUS HEATING SHOULD SUPPORT
ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS MAINLY THIS
AFTERNOON. EXPECT THE GREATER THUNDERSTORM COVERAGE IN THE EAST
PART CLOSER TO THE TROPICAL PLUME OF MOISTURE SHOWN BY THE WATER
VAPOR IMAGERY. CONVERGENCE ASSOCIATED WITH THE SEA- BREEZE FRONT
SHOULD ALSO AID COVERAGE IN THE EAST PART LATER THIS AFTERNOON.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM GENERALLY INDICATES
WEAK TO MODERATE INSTABILITY AND WEAK SHEAR. THE THREAT OF SEVERE
THUNDERSTORMS APPEARS LOW AT THIS TIME. THE GUIDANCE CONSENSUS
SUPPORTS HIGHS IN THE MIDDLE 80S WHICH IS NEAR CLIMATOLOGY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
THE HIGH OFF THE SOUTHEAST COAST WILL CONTINUE TO DOMINATE
THROUGH WEDNESDAY NIGHT. THE MODELS SHOW CONSIDERATE MOISTURE IN
THE SOUTHERLY FLOW ON THE BACKSIDE OF THE OFFSHORE HIGH. EXPECT
SCATTERED THUNDERSTORMS ESPECIALLY DURING THE TIME OF MAXIMUM
HEATING. THE GUIDANCE CONSENSUS SUPPORTS CHANCE POPS. ALSO USED
THE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING COLD FRONT SUPPORTS
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT BUT THE MODELS SHOW
DEEPER MOISTURE SHIFTING FARTHER EASTWARD AHEAD OF THE FRONT. THE
GFS ENSEMBLE MEAN PLUS OPERATIONAL GFS AND ECMWF MOS SUPPORT
CHANCE POPS. THE DRY AIR MASS BEHIND THE FRONT SHOULD DOMINATE
DURING THE REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
LOW CLOUDS HAVE DEVELOPED OVER MUCH OF THE AREA EARLY THIS MORNING.
CIGS MOSTLY IN THE IFR/LIFR RANGE...WITH LIFR VSBYS AT AGS. CAE VWP
INDICATING 20 KT LOW-LEVEL JET. FOG AND LOW STRATUS SHOULD DISSIPATE
BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE PERIOD.
WINDS WILL PICK UP OUT OF THE SOUTH TO SOUTHEAST AROUND 5-7 KNOTS.
WIDELY SCTD CONVECTION POSSIBLE LATER THIS AFTERNOON BUT NOT ENOUGH
CONFIDENCE TO MENTION AT ANY OF THE TAF SITES AT THIS TIME. MODEL
DATA SEEMS TO INDICATE THAT BULK OF CONVECTION THAT MAY DEVELOP
LATER THIS AFTERNOON MAY BE EAST OF THE TAF SITES. SOME MVFR FOG MAY
DEVELOP EARLY WEDNESDAY MORNING TOWARDS THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KFFC 211147
AFDFFC
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
735 AM EDT TUE MAY 21 2013
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
UPPER RIDGE CONTINUES BUILDING OVER THE SOUTHEAST TODAY WITH AN
UPPER LOW NEAR SOUTHEAST GA/NORTHEAST FL. THE AIR MASS REMAINS
UNSTABLE HOWEVER WATER VAPOR SHOWS SOME DRIER AIR HAS WORKED INTO
NORTHWEST GA. HAVE KEPT A SLIGHT CHANCE/LOW CHANCE POPS MAINLY OVER
THE EASTERN HALF OF THE CWA THIS AFTERNOON AND EVENING...CLOSER TO
THE UPPER LOW AND BETTER MOISTURE. TONIGHT LOOKS LIKE A LULL BETWEEN
SYSTEMS AND HAVE ONLY INCLUDED SLIGHT CHANCE POPS ACROSS THE EXTREME
NORTH. THE GFS HINTS AT A SHORT WAVE CROSSING THE TN VALLEY
OVERNIGHT. A CLOSED UPPER LOW MOVING INTO THE GREAT LAKES REGION BY
WEDNESDAY SHOULD PUSH A FRONT INTO THE LOWER MISSISSIPPI VALLEY
TOWARD GEORGIA. THE MODELS WANT TO KEEP THE FRONT WEST OF THE CWA
DURING THE DAY...BUT AN INCREASE IN MOISTURE AND INSTABILITY SHOULD
SUPPORT BETTER CHANCES OF THUNDERSTORMS ACROSS THE CWA BY WEDNESDAY
AFTERNOON. MAV/MET TEMPERATURES ARE CLOSE AND HAVE TAKEN A
COMPROMISE.
41
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
WEAK COLD FRONT APPROACHING WITH AN UPPER LEVEL TROUGH/SHORT WAVE
FORECAST TO MOVE INTO THE AREA WEDNESDAY NIGHT AND WITH ASSOCIATED
MOISTURE AND INSTABILITY...SCATTERED SHOWERS AND THUNDERSTORMS
ARE REASONABLE...MOST SO FOR THE EVENING HOURS. THE WEAK COLD
FRONT MOVES INTO THE AREA ON THURSDAY. IT IS UNCLEAR HOW MUCH
CONVECTION WILL BE ASSOCIATED WITH THE FRONT. THE BEST INSTABILITY
IS FORECAST OVER CENTRAL GA WITH THE BEST UPPER SUPPORT OVER N GA.
AT THIS TIME IT SEEMS REASONABLE THAT THERE WILL BE A CHANCE OF
SHOWERS AND THUNDERSTORMS...MOST SO IN THE AFTERNOON. THE MAIN
UPPER TROUGH MOVES E FOR FRIDAY WITH A DRIER AIRMASS MOVING OVER
THE AREA BEHIND THE FRONT AS SURFACE HIGH PRESSURE BUILDS ALONG
WITH A MUCH DRIER NW FLOW. DRY CONDITIONS CONTINUE SATURDAY AS
HIGH PRESSURE MOVES ACROSS THE EASTERN STATES. SUNDAY LOOKS TO BE
MAINLY DRY AS WELL EXCEPT THE NW FLOW ALOFT BEGINS TO BECOME MORE
ACTIVE TO THE N WITH SOME MOISTURE SKIRTING BY THE AREA. MOISTURE
CONTINUES TO SKIRT BY MONDAY AND TUESDAY WITH A SHARP GRADIENT OF
SIGNIFICANT MOISTURE AT THE GA/SC LINE. FOR NOW WILL LEAVE A DRY
FORECAST FOR MONDAY/TUESDAY AND CONTINUE TO MONITOR THE PROGRESS
OF THE NW FLOW. TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF
NORMAL THROUGH THE PERIOD EXCEPT SATURDAY AND SUNDAY MORNING LOWS
RUNNING 5-10 DEGREES BELOW NORMAL.
BDL
&&
.AVIATION...
12Z UPDATE...
EXPECTING VFR TODAY WITH SCT TO BKN CLOUDS AT OR ABOVE 040. IFR
VISIBILITIES WILL IMPROVE QUICKLY THIS MORNING AS MOST AREAS OF FOG
ARE SHALLOW. WIDELY SCATTERED CONVECTION POSSIBLE THIS AFTERNOON AND
EVENING. PROBABILITY OF HAVING A THUNDERSTORM AFFECT THE TAF SITES
IS LOW SO HAVE LEFT THUNDER OUT OF FORECAST FOR NOW. WINDS EXPECTED
TO BECOME SOUTHWEST LATER THIS MORNING AROUND 5 TO 8KT. WINDS WILL
GRADUALLY SWITCH BACK AROUND TO THE SSE AGAIN BY 00Z THIS EVENING
BUT WILL BE GENERALLY LESS THAN 5KT. .
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF SW WINDS. HIGH CONFIDENCE ON ALL
OTHER ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 64 86 64 / 30 30 40 40
ATLANTA 86 67 84 66 / 10 10 50 40
BLAIRSVILLE 82 60 81 60 / 30 30 50 50
CARTERSVILLE 86 64 85 63 / 10 10 50 40
COLUMBUS 90 68 88 68 / 10 10 30 30
GAINESVILLE 85 66 84 64 / 30 30 50 40
MACON 89 64 88 65 / 20 20 30 30
ROME 86 63 85 62 / 10 20 50 40
PEACHTREE CITY 87 61 86 63 / 10 10 50 30
VIDALIA 88 69 88 68 / 30 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....BDL
AVIATION...41
000
FXUS62 KCHS 211145
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
745 AM EDT TUE MAY 21 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL DROP THROUGH THE AREA ON FRIDAY WITH DRY HIGH PRESSURE BUILDING
IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NEAR DAWN...ANOTHER MILD MORNING ACROSS THE REGION AS A MOIST
ATMOSPHERE PERSISTS OVER THE FORECAST AREA. WATER VAPOR SATELLITE
IMAGERY INDICATES A WEAK MID LOW LEVEL LOW PRESSURE NOT FAR FROM
JACKSONVILLE FLORIDA...EMBEDDED IN A 500 MB TROUGH AXIS THAT RUNS
N THROUGH CHARLESTON TO GREENSBORO NC. AREAS OF LAYERED CLOUDS
EARLY THIS MORNING WITH POCKETS OF STRATUS AND FOG OVER INLAND
AREAS. WEAK UPPER DIFLUENCE AND MOIST COASTAL CONVERGENCE NOTED
ON LATEST MESOANALYSIS OVER EASTERN SOUTH CAROLINA AND AN AREA OF
HEAVY RAINFALL WAS EASING INTO NE CHARLESTON COUNTY AND WEAKENING
AFTER DUMPING PLENTY OF RAIN OVER SOUTHERN BERKELEY COUNTY. RADAR
ESTIMATED RAINFALL OVER 4 INCHES OF RAIN SE OF CYPRESS GARDENS.
TODAY...THE UPPER TROUGH DOES NOT MOVE MUCH AND EMBEDDED FEATURES
TEND TO WEAKEN WITH TIME. THE DEEPEST MOISTURE CONTINUES TO RESIDE
OVER SE SOUTH CAROLINA ALONG AND E OF INTERSTATE 95 INCLUDING THE
CHARLESTON AND CENTRAL SOUTH CAROLINA COASTAL AREAS. THROUGH MIDDAY
CONVECTIVE RAINS WILL BEGIN TO DEVELOP AS THE LAND MASS QUICKLY
WARMS WITH THE STEEP SUN ANGLE THIS TIME OF YEAR. THERE COULD BE A
FEW HEAVY DOWNPOURS ALONG THE COAST N OF BEAUFORT IF RECENT TRENDS
FROM THE RAP MODEL PAN OUT. CONVECTIVE TEMPS ARE PRETTY LOW TODAY
AND WE THINK SCATTERED CONVECTIVE RAINS WILL DEVELOP SOUTH ALONG
THE GEORGIA SEA BREEZE AND PROPAGATE W AND SW THIS AFTERNOON. 00Z
MODELS PROGS DIFFER ON THE AMOUNT OF INSTABILITY THIS AFTERNOON
BUT THE OPERATIONAL 13K RUC SHOWS DECENT POTENTIAL FOR SHORT-LIVED
BUT STRONG UPDRAFT POTENTIAL. OUR THINKING FOR SIGNIFICANT WEATHER
TODAY IS SIMILAR TO YESTERDAY/S REASONING...LOCALIZED DOWNPOURS
MORE LIKELY AND ONLY AN ISOLATED SEVERE WEATHER POTENTIAL AS BEST
MID LEVEL INSTABILITY AND LOW AND MID LEVEL LAPSE RATES LINGER W
OF THE AREA.
A COUPLE OF CHANGES WE MADE TO OUR FORECAST TODAY. WE RAISED POPS
TO 40-50 PERCENT IN THE CHARLESTON QUAD-COUNTY REGION AND RAISING
HIGH TEMPS OVER INLAND SE GEORGIA ZONES FURTHER INTO THE UPPER
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
INLAND CONVECTIVE RAINS WILL BE ENDING EARLY IN THE EVENING AS
THE SEA BREEZE GETS WELL INLAND AND CONVERGENCE DIMINISHES. NO
CHANGES TO THE FORECAST TONIGHT WITH CLOUDS GRADUALLY THINNING
AND LOWS 65-70 DEGREES. WE MAY NEED TO EVENTUALLY ADD SOME PATCHY
FOG IN AGAIN TONIGHT...DEPENDENT ON TRENDS WITH CLOUD DISSIPATION.
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY INTO THURSDAY WITH
BROAD UPPER TROUGHING AND ATLANTIC HIGH PRESSURE. SOUTHERLY
LOW-LEVEL FLOW WILL MAINTAIN A FAIRLY MOIST ATMOSPHERE AND HELP PUSH
A SEABREEZE INLAND EACH DAY. THE UPPER TROUGHING WILL CREATE A
SOMEWHAT MORE FAVORABLE ENVIRONMENT FOR CONVECTION TO DEVELOP...
PRIMARILY DRIVEN BY THE SEABREEZE AND BOUNDARY INTERACTIONS. WE KEPT
POPS IN THE 20-30 PERCENT RANGE BOTH DAYS.
THE MODELS ARE NOW QUITE A BIT FASTER AND IN BETTER AGREEMENT
REGARDING A COLD FRONT PUSHING THROUGH FRIDAY MORNING. WE REMOVED
POPS ON FRIDAY AND SHOW DEWPOINTS DROPPING INTO THE UPPER 50S TO
AROUND 60 DURING THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
KCHS...THE MORNING IS LOOKING WETTER AND WETTER WITH EACH PASSING
HOUR THIS MORNING. PATCHY MVFR/IFR CIGS WILL LINGER THROUGH MID MORNING
OR UNTIL RAINS DIMINISH. ADDITIONAL RAINS ARE LIKELY WITH THE SEA
BREEZE THIS AFTERNOON BUT SHOULD EVENTUALLY DEVELOP W OF THE
TERMINAL BY LATER IN THE DAY. TONIGHT...MAINLY VFR BUT WILL WATCH
FOR LATE NIGHT LOW CLOUDS AND PATCHY FOG WITH WET SOILS AND LIGHT
WINDS.
KSAV...A FEW SHOWERS MAY DEVELOP WITH THE INITIATION OF THE SEA
BREEZE LATE MORNING OR EARLY AFTERNOON ALONG WITH BRIEF MORNING
MVFR CIGS POSSIBLE. BEST CHANCES FOR SHOWERS/TSTMS WILL BE WITH
AFTERNOON CONVECTION WHICH COULD BE MOVING SW ALONG OR JUST W OF
INTERSTATE 95. MAINLY VFR TONIGHT BUT THERE ARE CHANCES OF LATE
NIGHT MVFR/IFR CIGS AND POSSIBLY LIGHT FOG...ESPECIALLY IF SKIES
CLEAR.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
THROUGH TONIGHT...THE STEADY STATE SYNOPTIC PATTERN CONTINUES UNABATED.
OFFSHORE RIDGE OF HIGH PRESSURE EXTENDS W ACROSS THE COASTAL WATERS...
GENERATING SE AND S WINDS LESS THAN 15 KT AND SEAS IN THE 2-4 FOOT
RANGE...HIGHEST OVER OUTER GEORGIA WATERS BEYOND 20 NM.
HIGH PRESSURE WILL SIT OVER THE WESTERN ATLANTIC UNTIL FRIDAY WHEN A
CANADIAN HIGH DROPS SOUTHEAST. WE MAY SEE A BRIEF PERIOD OF SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT INTO SATURDAY AS THE GRADIENT
TIGHTENS AND COLD ADVECTION MIXES SOME DECENT WINDS TO THE SURFACE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL
000
FXUS62 KCAE 211028
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
628 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC
WILL DOMINATE TODAY. A MOIST SOUTH FLOW IS ASSOCIATED WITH THIS
FEATURE. THE HIGH LOW-LEVEL MOISTURE WILL SUPPORT STRATUS AND
AREAS OF FOG EARLY THIS MORNING. A MID-LEVEL SHORTWAVE TROUGH WILL
SUPPORT SHOWERS AND THUNDERSTORMS IN THE EXTREME NORTHEAST PART
EARLY THIS MORNING. THE MOISTURE PLUS HEATING SHOULD SUPPORT
ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS MAINLY THIS
AFTERNOON. EXPECT THE GREATER THUNDERSTORM COVERAGE IN THE EAST
PART CLOSER TO THE TROPICAL PLUME OF MOISTURE SHOWN BY THE WATER
VAPOR IMAGERY. CONVERGENCE ASSOCIATED WITH THE SEA-BREEZE FRONT
SHOULD ALSO AID COVERAGE IN THE EAST PART LATER THIS AFTERNOON.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM GENERALLY INDICATES
WEAK TO MODERATE INSTABILITY AND WEAK SHEAR. THE THREAT OF SEVERE
THUNDERSTORMS APPEARS LOW AT THIS TIME. THE GUIDANCE CONSENSUS
SUPPORTS HIGHS IN THE MIDDLE 80S WHICH IS NEAR CLIMATOLOGY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE HIGH OFF THE SOUTHEAST COAST WILL CONTINUE TO DOMINATE
THROUGH WEDNESDAY NIGHT. THE MODELS SHOW CONSIDERATE MOISTURE IN
THE SOUTHERLY FLOW ON THE BACKSIDE OF THE OFFSHORE HIGH. EXPECT
SCATTERED THUNDERSTORMS ESPECIALLY DURING THE TIME OF MAXIMUM
HEATING. THE GUIDANCE CONSENSUS SUPPORTS CHANCE POPS. ALSO USED
THE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING COLD FRONT SUPPORTS
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT BUT THE MODELS SHOW
DEEPER MOISTURE SHIFTING FARTHER EASTWARD AHEAD OF THE FRONT. THE
GFS ENSEMBLE MEAN PLUS OPERATIONAL GFS AND ECMWF MOS SUPPORT
CHANCE POPS. THE DRY AIR MASS BEHIND THE FRONT SHOULD DOMINATE
DURING THE REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
LOW CLOUDS HAVE DEVELOPED OVER MUCH OF THE AREA EARLY THIS MORNING.
CIGS MOSTLY IN THE IFR/LIFR RANGE...WITH LIFR VSBYS AT AGS. CAE VWP
INDICATING 20 KT LOW-LEVEL JET. FOG AND LOW STRATUS SHOULD DISSIPATE
BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE PERIOD.
WINDS WILL PICK UP OUT OF THE SOUTH TO SOUTHEAST AROUND 5-7 KNOTS.
WIDELY SCTD CONVECTION POSSIBLE LATER THIS AFTERNOON BUT NOT ENOUGH
CONFIDENCE TO MENTION AT ANY OF THE TAF SITES AT THIS TIME. MODEL
DATA SEEMS TO INDICATE THAT BULK OF CONVECTION THAT MAY DEVELOP
LATER THIS AFTERNOON MAY BE EAST OF THE TAF SITES. SOME MVFR FOG MAY
DEVELOP EARLY WEDNESDAY MORNING TOWARDS THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 210802
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
402 AM EDT TUE MAY 21 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD FRONT
WILL DROP THROUGH THE AREA ON FRIDAY WITH DRY HIGH PRESSURE BUILDING
IN NEXT WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE-DAWN...ANOTHER MILD MORNING ACROSS THE REGION AS A MOIST
ATMOSPHERE PERSISTS OVER THE FORECAST AREA. WATER VAPOR SATELLITE
IMAGERY INDICATES A WEAK MID LOW LEVEL LOW PRESSURE NOT FAR FROM
JACKSONVILLE FLORIDA...EMBEDDED IN A 500 MB TROUGH AXIS THAT RUNS
N THROUGH CHARLESTON TO GREENSBORO NC. AREAS OF LAYERED CLOUDS
EARLY THIS MORNING WITH POCKETS OF STRATUS EXPECTED TO DEVELOP
OVER INLAND AREAS. WE MAINTAINED PATCHY FOG MENTIONS IN OUR
FORECAST WHERE SKIES CLEARED OVERNIGHT. WEAK UPPER DIFLUENCE AND
MOIST COASTAL CONVERGENCE NOTED ON LATEST MESOANALYSIS OVER EASTERN
SOUTH CAROLINA AND WE MAINTAINED 20/30 POPS ACROSS THE CHARLESTON
TRI-COUNTY AREA AS DAYBREAK NEARS...ELSEWHERE MAINLY DRY EARLY ON.
TODAY...THE UPPER TROUGH DOES NOT MOVE MUCH AND EMBEDDED FEATURES
TEND TO WEAKEN WITH TIME. THE DEEPEST MOISTURE CONTINUES TO RESIDE
OVER SE SOUTH CAROLINA ALONG AND E OF INTERSTATE 95 INCLUDING THE
CHARLESTON AND CENTRAL SOUTH CAROLINA COASTAL AREAS. THROUGH MIDDAY
CONVECTIVE RAINS WILL BEGIN TO DEVELOP AS THE LAND MASS QUICKLY
WARMS WITH THE STEEP SUN ANGLE THIS TIME OF YEAR. THERE COULD BE A
FEW HEAVY DOWNPOURS ALONG THE COAST N OF BEAUFORT IF RECENT TRENDS
FROM THE RAP MODEL PAN OUT. CONVECTIVE TEMPS ARE PRETTY LOW TODAY
AND WE THINK SCATTERED CONVECTIVE RAINS WILL DEVELOP SOUTH ALONG
THE GEORGIA SEA BREEZE AND PROPAGATE W AND SW THIS AFTERNOON. 00Z
MODELS PROGS DIFFER ON THE AMOUNT OF INSTABILITY THIS AFTERNOON
BUT THE OPERATIONAL 13K RUC SHOWS DECENT POTENTIAL FOR SHORT-LIVED
BUT STRONG UPDRAFT POTENTIAL. OUR THINKING FOR SIGNIFICANT WEATHER
TODAY IS SIMILAR TO YESTERDAY/S REASONING...LOCALIZED DOWNPOURS
MORE LIKELY AND ONLY AN ISOLATED SEVERE WEATHER POTENTIAL AS BEST
MID LEVEL INSTABILITY AND LOW AND MID LEVEL LAPSE RATES LINGER W
OF THE AREA.
A COUPLE OF CHANGES WE MADE TO OUR FORECAST TODAY. WE RAISED POPS
TO 40-50 PERCENT IN THE CHARLESTON QUAD-COUNTY REGION AND RAISING
HIGH TEMPS OVER INLAND SE GEORGIA ZONES FURTHER INTO THE UPPER
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
INLAND CONVECTIVE RAINS WILL BE ENDING EARLY IN THE EVENING AS
THE SEA BREEZE GETS WELL INLAND AND CONVERGENCE DIMINISHES. NO
CHANGES TO THE FORECAST TONIGHT WITH CLOUDS GRADUALLY THINNING
AND LOWS 65-70 DEGREES. WE MAY NEED TO EVENTUALLY ADD SOME PATCHY
FOG IN AGAIN TONIGHT...DEPENDENT ON TRENDS WITH CLOUD DISSIPATION.
A FAIRLY SIMILAR PATTERN WILL PERSIST WEDNESDAY INTO THURSDAY WITH
BROAD UPPER TROUGHING AND ATLANTIC HIGH PRESSURE. SOUTHERLY
LOW-LEVEL FLOW WILL MAINTAIN A FAIRLY MOIST ATMOSPHERE AND HELP PUSH
A SEABREEZE INLAND EACH DAY. THE UPPER TROUGHING WILL CREATE A
SOMEWHAT MORE FAVORABLE ENVIRONMENT FOR CONVECTION TO DEVELOP...
PRIMARILY DRIVEN BY THE SEABREEZE AND BOUNDARY INTERACTIONS. WE KEPT
POPS IN THE 20-30 PERCENT RANGE BOTH DAYS.
THE MODELS ARE NOW QUITE A BIT FASTER AND IN BETTER AGREEMENT
REGARDING A COLD FRONT PUSHING THROUGH FRIDAY MORNING. WE REMOVED
POPS ON FRIDAY AND SHOW DEWPOINTS DROPPING INTO THE UPPER 50S TO
AROUND 60 DURING THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THERE IS GOOD MODEL AGREEMENT THAT DRY CANADIAN HIGH PRESSURE WILL
EXPAND SOUTHEAST INTO THE FORECAST AREA OVER THE WEEKEND THEN SHIFT
OFFSHORE. DEWPOINTS LOOK TO DROP INTO THE LOWER 50S SATURDAY AND
SUNDAY...WHICH COMBINED WITH HIGHS IN THE LOWER 80S WILL RESULT IN
PLEASANT SPRING WEATHER. OVERNIGHT LOWS WILL PROBABLY DROP INTO THE
UPPER 50S IN SPOTS. LOW-LEVEL MOISTURE INCREASES EARLY NEXT WEEK AS
THE SURFACE HIGH SHIFTS OFFSHORE...BUT WE DID NOT SEE ANY STRONG
SYNOPTIC SCALE FEATURES TO WARRANT ADDING PRECIP.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
KCHS...ISOLATED SHOWERS AND BRIEF MVFR CIGS POSSIBLE OVERNIGHT...
OTHERWISE VFR UNTIL DAYBREAK. A RICH TROPICAL-LIKE FEED OF
MOISTURE AND COASTAL CONVERGENCE WILL INTERACT WITH THE SEA BREEZE
DURING THE LATE MORNING AND AFTERNOON HOURS TODAY...PRODUCING
SCATTERED SHRA AND POSSIBLE TSRA. FOR NOW WE MAINTAINED A PROB30
GROUP FOR SHRA AND MVFR CONDITIONS FROM 15-21Z UNTIL TRENDS CAN BE
BETTER DEFINED.
KSAV...WE ANTICIPATE A FEW HOURS OF MVFR CONDITIONS IN LIGHT
LOW STRATUS/STRATOCUMULUS OVERNIGHT AND CONTINUE TO INDICATE THAT
TREND. ISOLATED TO SCATTERED CONVECTION WILL FORM ALONG THE SEA
BREEZE BOUNDARY DURING LATE MORNING THROUGH MID AFTERNOON...THUS
A PROB30 GROUP FROM 16-21Z WAS MAINTAINED.
EXTENDED AVIATION...SPORADIC REDUCTIONS IN CEILINGS/VSBYS MAINLY IN
AFTERNOON/EVENING SHOWERS OR STORMS THROUGH THURSDAY.
&&
.MARINE...
THROUGH TONIGHT...THE STEADY STATE SYNOPTIC PATTERN CONTINUES UNABATED.
OFFSHORE RIDGE OF HIGH PRESSURE EXTENDS W ACROSS THE COASTAL WATERS...
GENERATING SE AND S WINDS LESS THAN 15 KT AND SEAS IN THE 2-4 FOOT
RANGE...HIGHEST OVER OUTER GEORGIA WATERS BEYOND 20 NM.
HIGH PRESSURE WILL SIT OVER THE WESTERN ATLANTIC UNTIL FRIDAY WHEN A
CANADIAN HIGH DROPS SOUTHEAST. WE MAY SEE A BRIEF PERIOD OF SMALL
CRAFT ADVISORY CONDITIONS FRIDAY NIGHT INTO SATURDAY AS THE GRADIENT
TIGHTENS AND COLD ADVECTION MIXES SOME DECENT WINDS TO THE SURFACE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL
000
FXUS62 KCAE 210755
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
355 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC
WILL DOMINATE TODAY. A MOIST SOUTH FLOW IS ASSOCIATED WITH THIS
FEATURE. THE HIGH LOW-LEVEL MOISTURE WILL SUPPORT STRATUS AND
AREAS OF FOG EARLY THIS MORNING. THE MOISTURE PLUS HEATING SHOULD
SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS MAINLY THIS
AFTERNOON. EXPECT THE GREATER THUNDERSTORM COVERAGE IN THE EAST
PART CLOSER TO THE TROPICAL PLUME OF MOISTURE SHOWN BY THE WATER
VAPOR IMAGERY. CONVERGENCE ASSOCIATED WITH THE SEA-BREEZE FRONT
SHOULD ALSO AID COVERAGE IN THE EAST PART LATER THIS AFTERNOON.
CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM GENERALLY INDICATES
WEAK TO MODERATE INSTABILITY AND WEAK SHEAR. THE THREAT OF SEVERE
THUNDERSTORMS APPEARS LOW AT THIS TIME. THE GUIDANCE CONSENSUS
SUPPORTS HIGHS IN THE MIDDLE 80S WHICH IS NEAR CLIMATOLOGY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE HIGH OFF THE SOUTHEAST COAST WILL CONTINUE TO DOMINATE
THROUGH WEDNESDAY NIGHT. THE MODELS SHOW CONSIDERATE MOISTURE IN
THE SOUTHERLY FLOW ON THE BACKSIDE OF THE OFFSHORE HIGH. EXPECT
SCATTERED THUNDERSTORMS ESPECIALLY DURING THE TIME OF MAXIMUM
HEATING. THE GUIDANCE CONSENSUS SUPPORTS CHANCE POPS. ALSO USED
THE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING COLD FRONT SUPPORTS
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT BUT THE MODELS SHOW
DEEPER MOISTURE SHIFTING FARTHER EASTWARD AHEAD OF THE FRONT. THE
GFS ENSEMBLE MEAN PLUS OPERATIONAL GFS AND ECMWF MOS SUPPORT
CHANCE POPS. THE DRY AIR MASS BEHIND THE FRONT SHOULD DOMINATE
DURING THE REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
LOW CLOUDS HAVE DEVELOPED OVER MUCH OF THE AREA EARLY THIS MORNING.
CIGS MOSTLY IN THE IFR/LIFR RANGE...ALTHOUGH AGS/DNL REMAIN VFR.
CAE VWP INDICATING 25-30 KT LOW-LEVEL JET. LIGHT TO CALM WINDS
OVERNIGHT WILL ALLOW SOME RADIATIONAL COOLING AND EXPECT SOME FOG
TO DEVELOP DURING THE PRE- DAWN HOURS...BUT CONFIDENCE IS LOW AT
THIS TIME AS TO HOW LOW CIGS WILL GO. ANY FOG AND LOW STRATUS
SHOULD DISSIPATE BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE PERIOD. WINDS WILL PICK UP OUT OF THE SOUTH TO
SOUTHEAST AROUND 5-7 KNOTS. WIDELY SCTD CONVECTION POSSIBLE LATER
THIS AFTERNOON BUT NOT ENOUGH CONFIDENCE TO MENTION AT ANY OF THE
TAF SITES AT THIS TIME. MODEL DATA SEEMS TO INDICATE THAT BULK OF
CONVECTION THAT MAY DEVELOP LATER THIS AFTERNOON MAY BE EAST OF
THE TAF SITES.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KFFC 210751
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
351 AM EDT TUE MAY 21 2013
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
UPPER RIDGE CONTINUES BUILDING OVER THE SOUTHEAST TODAY WITH AN
UPPER LOW NEAR SOUTHEAST GA/NORTHEAST FL. THE AIR MASS REMAINS
UNSTABLE HOWEVER WATER VAPOR SHOWS SOME DRIER AIR HAS WORKED INTO
NORTHWEST GA. HAVE KEPT A SLIGHT CHANCE/LOW CHANCE POPS MAINLY OVER
THE EASTERN HALF OF THE CWA THIS AFTERNOON AND EVENING...CLOSER TO
THE UPPER LOW AND BETTER MOISTURE. TONIGHT LOOKS LIKE A LULL BETWEEN
SYSTEMS AND HAVE ONLY INCLUDED SLIGHT CHANCE POPS ACROSS THE EXTREME
NORTH. THE GFS HINTS AT A SHORT WAVE CROSSING THE TN VALLEY
OVERNIGHT. A CLOSED UPPER LOW MOVING INTO THE GREAT LAKES REGION BY
WEDNESDAY SHOULD PUSH A FRONT INTO THE LOWER MISSISSIPPI VALLEY
TOWARD GEORGIA. THE MODELS WANT TO KEEP THE FRONT WEST OF THE CWA
DURING THE DAY...BUT AN INCREASE IN MOISTURE AND INSTABILITY SHOULD
SUPPORT BETTER CHANCES OF THUNDERSTORMS ACROSS THE CWA BY WEDNESDAY
AFTERNOON. MAV/MET TEMPERATURES ARE CLOSE AND HAVE TAKEN A
COMPROMISE.
41
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
WEAK COLD FRONT APPROACHING WITH AN UPPER LEVEL TROUGH/SHORT WAVE
FORECAST TO MOVE INTO THE AREA WEDNESDAY NIGHT AND WITH ASSOCIATED
MOISTURE AND INSTABILITY...SCATTERED SHOWERS AND THUNDERSTORMS
ARE REASONABLE...MOST SO FOR THE EVENING HOURS. THE WEAK COLD
FRONT MOVES INTO THE AREA ON THURSDAY. IT IS UNCLEAR HOW MUCH
CONVECTION WILL BE ASSOCIATED WITH THE FRONT. THE BEST INSTABILITY
IS FORECAST OVER CENTRAL GA WITH THE BEST UPPER SUPPORT OVER N GA.
AT THIS TIME IT SEEMS REASONABLE THAT THERE WILL BE A CHANCE OF
SHOWERS AND THUNDERSTORMS...MOST SO IN THE AFTERNOON. THE MAIN
UPPER TROUGH MOVES E FOR FRIDAY WITH A DRIER AIRMASS MOVING OVER
THE AREA BEHIND THE FRONT AS SURFACE HIGH PRESSURE BUILDS ALONG
WITH A MUCH DRIER NW FLOW. DRY CONDITIONS CONTINUE SATURDAY AS
HIGH PRESSURE MOVES ACROSS THE EASTERN STATES. SUNDAY LOOKS TO BE
MAINLY DRY AS WELL EXCEPT THE NW FLOW ALOFT BEGINS TO BECOME MORE
ACTIVE TO THE N WITH SOME MOISTURE SKIRTING BY THE AREA. MOISTURE
CONTINUES TO SKIRT BY MONDAY AND TUESDAY WITH A SHARP GRADIENT OF
SIGNIFICANT MOISTURE AT THE GA/SC LINE. FOR NOW WILL LEAVE A DRY
FORECAST FOR MONDAY/TUESDAY AND CONTINUE TO MONITOR THE PROGRESS
OF THE NW FLOW. TEMPERATURES GENERALLY RUNNING WITHIN 5 DEGREES OF
NORMAL THROUGH THE PERIOD EXCEPT SATURDAY AND SUNDAY MORNING LOWS
RUNNING 5-10 DEGREES BELOW NORMAL.
BDL
&&
.AVIATION...
06Z UPDATE...
SCATTERED CLOUDS AT OR ABOVE 050 THIS MORNING. LOW CONFIDENCE ON
MVFR STRATUS FORMING THIS MORNING...HOWEVER SOME MVFR VISIBILITY
IS POSSIBLE UNTIL 14Z. VFR EXPECTED THROUGH THE AFTERNOON EXCEPT IN
SOME WIDELY SCATTERED CONVECTION. PROBABILITY OF HAVING A
THUNDERSTORM AFFECT THE TAF SITES IS LOW SO HAVE LEFT THUNDER OUT
OF FORECAST FOR NOW. SSE WINDS EXPECTED OVERNIGHT AT 5KT OR
LESS...WITH SSW EXPECTED BY LATE MORNING. WINDS WILL GRADUALLY
SWITCH BACK AROUND TO THE SSE AGAIN BY 23-00Z THIS EVENING.
//ATL CONFIDENCE...06Z UPDATE...
LOW TO MEDIUM CONFIDENCE ON MVFR CIGS THIS MORNING. HIGH CONFIDENCE
ON ALL OTHER ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 64 86 64 / 30 30 40 40
ATLANTA 86 67 84 66 / 10 10 50 40
BLAIRSVILLE 82 60 81 60 / 30 30 50 50
CARTERSVILLE 86 64 85 63 / 10 10 50 40
COLUMBUS 90 68 88 68 / 10 10 30 30
GAINESVILLE 85 66 84 64 / 30 30 50 40
MACON 89 64 88 65 / 20 20 30 30
ROME 86 63 85 62 / 10 20 50 40
PEACHTREE CITY 87 61 86 63 / 10 10 50 30
VIDALIA 88 69 88 68 / 30 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....BDL
AVIATION...41
000
FXUS62 KCAE 210720
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
320 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC
WILL DOMINATE TODAY. A MOIST SOUTH FLOW IS ASSOCIATED WITH THIS
FEATURE. THE HIGH LOW-LEVEL MOISTURE WILL SUPPORT STRATUS AND
AREAS OF FOG EARLY THIS MORNING. THE MOISTURE PLUS HEATING SHOULD
SUPPORT SCATTERED THUNDERSTORMS THIS AFTERNOON. EXPECT THE GREATER
THUNDERSTORM COVERAGE IN THE EAST PART CLOSER TO THE TROPICAL
PLUME OF MOISTURE SHOWN BY THE WATER VAPOR IMAGERY. CONVERGENCE
ASSOCIATED WITH THE SEA-BREEZE FRONT SHOULD ALSO AID COVERAGE IN
THE EAST PART. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
GENERALLY INDICATES WEAK TO MODERATE INSTABILITY AND WEAK SHEAR.
THE THREAT OF SEVERE THUNDERSTORMS APPEARS LOW AT THIS TIME. THE
GUIDANCE CONSENSUS SUPPORTS HIGHS IN THE MIDDLE 80S WHICH IS NEAR
CLIMATOLOGY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE HIGH OFF THE SOUTHEAST COAST WILL CONTINUE TO DOMINATE
THROUGH WEDNESDAY NIGHT. THE MODELS SHOW CONSIDERATE MOISTURE IN
THE SOUTHERLY FLOW ON THE BACKSIDE OF THE OFFSHORE HIGH. EXPECT
SCATTERED THUNDERSTORMS ESPECIALLY DURING THE TIME OF MAXIMUM
HEATING. THE GUIDANCE CONSENSUS SUPPORTS CHANCE POPS. ALSO USED
THE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING COLD FRONT SUPPORTS
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT BUT THE MODELS SHOW
DEEPER MOISTURE SHIFTING FARTHER EASTWARD AHEAD OF THE FRONT. THE
GFS ENSEMBLE MEAN PLUS OPERATIONAL GFS AND ECMWF MOS SUPPORT
CHANCE POPS. THE DRY AIR MASS BEHIND THE FRONT SHOULD DOMINATE
DURING THE REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
LOW CLOUDS HAVE DEVELOPED OVER MUCH OF THE AREA EARLY THIS MORNING.
CIGS MOSTLY IN THE IFR/LIFR RANGE...ALTHOUGH AGS/DNL REMAIN VFR.
CAE VWP INDICATING 25-30 KT LOW-LEVEL JET. LIGHT TO CALM WINDS
OVERNIGHT WILL ALLOW SOME RADIATIONAL COOLING AND EXPECT SOME FOG
TO DEVELOP DURING THE PRE- DAWN HOURS...BUT CONFIDENCE IS LOW AT
THIS TIME AS TO HOW LOW CIGS WILL GO. ANY FOG AND LOW STRATUS
SHOULD DISSIPATE BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE PERIOD. WINDS WILL PICK UP OUT OF THE SOUTH TO
SOUTHEAST AROUND 5-7 KNOTS. WIDELY SCTD CONVECTION POSSIBLE LATER
THIS AFTERNOON BUT NOT ENOUGH CONFIDENCE TO MENTION AT ANY OF THE
TAF SITES AT THIS TIME. MODEL DATA SEEMS TO INDICATE THAT BULK OF
CONVECTION THAT MAY DEVELOP LATER THIS AFTERNOON MAY BE EAST OF
THE TAF SITES.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 210600
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
200 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC
WILL DOMINATE TODAY. A MOIST SOUTH FLOW IS ASSOCIATED WITH THIS
FEATURE. THE HIGH LOW-LEVEL MOISTURE WILL SUPPORT STRATUS AND
AREAS OF FOG EARLY THIS MORNING. THE MOISTURE PLUS HEATING SHOULD
SUPPORT SCATTERED THUNDERSTORMS THIS AFTERNOON. EXPECT THE GREATER
THUNDERSTORM COVERAGE IN THE EAST PART CLOSER TO THE TROPICAL
PLUME OF MOISTURE SHOWN BY THE WATER VAPOR IMAGERY. CONVERGENCE
ASSOCIATED WITH THE SEA-BREEZE FRONT SHOULD ALSO AID COVERAGE IN
THE EAST PART. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
GENERALLY INDICATES WEAK TO MODERATE INSTABILITY AND WEAK SHEAR.
THE THREAT OF SEVERE THUNDERSTORMS APPEARS LOW AT THIS TIME. THE
GUIDANCE CONSENSUS SUPPORTS HIGHS IN THE MIDDLE 80S WHICH IS NEAR
CLIMATOLOGY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
THE HIGH OFF THE SOUTHEAST COAST WILL CONTINUE TO DOMINATE
THROUGH WEDNESDAY NIGHT. THE MODELS SHOW CONSIDERATE MOISTURE IN
THE SOUTHERLY FLOW ON THE BACKSIDE OF THE OFFSHORE HIGH. EXPECT
SCATTERED THUNDERSTORMS ESPECIALLY DURING THE TIME OF MAXIMUM
HEATING. THE GUIDANCE CONSENSUS SUPPORTS CHANCE POPS. ALSO USED
THE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING COLD FRONT SUPPORTS
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT BUT THE MODELS SHOW
DEEPER MOISTURE SHIFTING FARTHER EASTWARD AHEAD OF THE FRONT. THE
GFS ENSEMBLE MEAN PLUS OPERATIONAL GFS AND ECMWF MOS SUPPORT
CHANCE POPS. THE DRY AIR MASS BEHIND THE FRONT SHOULD DOMINATE
DURING THE REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SCTD SHOWERS/STORMS HAVE ENDED ACROSS THE AREA WITH MAINLY
CONVECTIVE DEBRIS CLOUDS REMAINING. THESE CLOUDS SHOULD THIN DURING
THE EARLY MORNING HOURS. LOW LEVEL JET IS NOT AS STRONG AND LOW
LEVEL MOISTURE REMAINS PLENTIFUL SO FOG FIGURES TO BE A MORE FAVORED
THREAT. LIGHT TO CALM WINDS OVERNIGHT WILL ALLOW SOME RADIATIONAL
COOLING AND EXPECT SOME FOG TO DEVELOP AFTER 07Z-09Z. WILL INCLUDE
SOME IFR VSBYS AT AGS/OGB AND POSSIBLE THEY COULD OCCUR AT CAE
09Z-12Z. CONFIDENCE IS A LITTLE HIGHER TONIGHT THAN PREVIOUS NIGHTS
BUT GUIDANCE HAS NOT BEEN GREAT AS OF LATE. ANY FOG SHOULD BURN OFF
BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE PERIOD.
WINDS WILL PICK UP OUT OF THE SOUTH TO SOUTHEAST AROUND 5-7 KNOTS.
WIDELY SCTD CONVECTION POSSIBLE LATER THIS AFTERNOON BUT NOT ENOUGH
CONFIDENCE TO MENTION AT ANY OF THE TAF SITES AT THIS TIME. MODEL
DATA SEEMS TO INDICATE THAT BULK OF CONVECTION THAT MAY DEVELOP
LATER THIS AFTERNOON MAY BE EAST OF THE TAF SITES.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KFFC 210542
AFDFFC
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
135 AM EDT TUE MAY 21 2013
.UPDATE...
OVERALL...FORECAST LOOKS TO BE ON TRACK WITH A FEW MINOR UPDATES.
HAVE MODIFIED TUESDAY POPS SLIGHTLY TO ACCOUNT FOR LATEST MODEL
TRENDS...BUT GENERALLY KEEPING CHANCE AND SLIGHT CHANCE POPS
CONCENTRATED OVER THE EASTERN PORTIONS OF THE CWA. LATEST MODELS
HAVE ALSO SCALED BACK ON LOW LEVEL MOISTURE FOR TUESDAY
MORNING...SO HAVE MADE SOME ADJUSTMENTS TO SKY COVER GRIDS. STILL
EXPECTING PATCHY TO AREAS OF FOG ACROSS LARGE PORTIONS OF THE
AREA AT THIS TIME. NO ADDITIONAL UPDATES ARE PLANNED AT THIS TIME.
31
&&
.PREV DISCUSSION... /ISSUED 814 PM EDT MON MAY 20 2013/
PREV DISCUSSION... /ISSUED 338 PM EDT MON MAY 20 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY/...
MODELS ALL IN GOOD AGREEMENT THROUGH THE SHORT TERM. THE UPPER LOW
THAT BROUGHT THE PRECIP TO THE REGION OVER THE WEEKEND IS SLOW TO
EXIT BUT IT IS DOING SO. SOME LINGERING CONVECTION SOUTH OF THE FALL
LINE WHERE THE CAP IS THE WEAKEST THIS AFTERNOON SHOULD DISSIPATE
AFTER SUNSET. EXPECT ANOTHER AREA OF LOW CLOUDS TUESDAY MORNING
ALONG WITH SOME LIGHT FOG BUT THIS SHOULD DISSIPATE AFTER SUNSET.
THE UPPER RIDGE CONTINUES TO BUILD INTO THE SOUTHEAST
TUESDAY...BECOMING MORE LIKE OUR SUMMER PATTERN WITH AFTERNOON AND
EVENING CONVECTION. ALL MODELS FORECAST PLENTY OF CAPE WITH LITTLE
CIN OVER THE AREA TUESDAY AFTERNOON WITH THE BEST INSTABILITY OVER
THE MOUNTAINS AND THE EASTERN PARTS OF THE CWA. WILL MAINTAIN SLIGHT
CHANCE/CHANCE POPS ACROSS MUCH OF THE CWA TUESDAY AFTERNOON. A
LITTLE MORE SUNSHINE WILL HELP TEMPS PUSH WELL INTO THE 80S WITH
SOME LOWER 90S ACROSS WEST CENTRAL GA ON TUESDAY.
17
LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
NO MAJOR CHANGES MADE TO THE EXTENDED FORECAST. UPPER LEVEL TROUGH
APPROACHING ON WEDNESDAY AND COMBINED WITH ASSOCIATED MOIST AND
INSTABILITY WILL GIVE POTENTIAL FOR NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS ACROSS MAINLY N GA AND MAINLY SCATTERED SHOWERS AND
STORMS FOR CENTRAL GA. A WEAK COLD FRONT GETS INTO THE AREA LATE
THURSDAY...POSSIBILITY ASSOCIATED WITH SOME UPPER LEVEL
SUPPORT...WILL GIVE THE CHANCE FOR SHOWERS AND STORMS. BEST
MOISTURE AND UPPER SUPPORT DRIFTING EAST ON FRIDAY ALLOWING FOR
ONLY A SLIGHT CHANCE OF SHOWERS AND STORMS. OVERALL MOISTURE AND
INSTABILITY APPEAR LACKING SATURDAY INTO MONDAY AND WHILE PRECIP
POTENTIAL IS NOT ZERO IT LOOKS TO BE LESS THAN 20 PERCENT AT THIS
TIME. TEMPERATURES RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH THE
PERIOD.
01
AVIATION...
06Z UPDATE...
SCATTERED CLOUDS AT OR ABOVE 050 THIS MORNING. LOW CONFIDENCE ON
MVFR STRATUS FORMING THIS MORNING...HOWEVER SOME MVFR VISIBILITY IS
POSSIBLE UNTIL 14Z. VFR EXPECTED THROUGH THE AFTERNOON EXCEP IN SOME
WIDELY SCATTERED CONVECTION. PROBABILITY OF HAVING A THUNDERSTORM
AFFECT THE TAF SITES IS LOW SO HAVE LEFT THUNDER OUT OF FORECAST FOR
NOW. SSE WINDS EXPECTED OVERNIGHT AT 5KT OR LESS...WITH SSW EXPECTED
BY LATE MORNING. WINDS WILL GRADUALLY SWITCH BACK AROUND TO THE SSE
AGAIN BY 23-00Z THIS EVENING.
//ATL CONFIDENCE...06Z UPDATE...
LOW TO MEDIUM CONFIDENCE ON MVFR CIGS THIS MORNING. HIGH CONFIDENCE
ON ALL OTHER ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 87 64 84 / 20 30 30 40
ATLANTA 67 86 67 82 / 10 20 20 50
BLAIRSVILLE 58 83 63 75 / 30 40 40 60
CARTERSVILLE 64 88 66 83 / 10 20 20 60
COLUMBUS 69 92 67 89 / 20 20 20 30
GAINESVILLE 64 85 66 81 / 20 30 40 60
MACON 65 89 64 88 / 30 20 20 30
ROME 63 89 66 82 / 10 10 20 70
PEACHTREE CITY 63 88 63 83 / 10 20 20 50
VIDALIA 68 89 68 87 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....11
AVIATION...41
000
FXUS62 KCHS 210535
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
135 AM EDT TUE MAY 21 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER THE AREA WILL DISSIPATE THROUGH
MID WEEK WHILE ATLANTIC HIGH PRESSURE PREVAILS UNTIL LATE WEEK. A
COLD FRONT WILL DROP THROUGH THE AREA FRIDAY...FOLLOWED BY HIGH
PRESSURE THROUGH NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WE HAVE EXPANDED SLIGHT CHANCE OF SHOWERS EASTWARD OF I-95 ACROSS A
LARGER PORTION OF SOUTHERN SOUTH CAROLINA OVERNIGHT...OTHERWISE
FEW CHANGES ON THE UPDATE EARLY THIS MORNING. DEBRIS CLOUDS HAVE
DECREASED BUT AREAS OF STRATUS AND STRATOCUMULUS EXPECTED TO
INCREASE OVER SE GEORGIA INTO SOUTHERN SOUTH CAROLINA.
IT/LL BE ANOTHER WARM AND VERY HUMID NIGHT...AND THUS RESTRICTING
LOWEST TEMPS ONLY IN THE MID AND UPPER 60S AWAY FROM THE BEACHES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
ATLANTIC HIGH PRESSURE WILL BE THE DOMINANT FEATURE AT THE SURFACE
TUESDAY AND WEDNESDAY. THE PERSISTENT UPPER SHORTWAVE MEANDERING
OVER THE SOUTHEAST STATES WILL GRADUALLY BECOME ABSORBED BY A TROUGH
AXIS TO THE WEST MID WEEK. THE UPPER TROUGH WILL THEN CONTINUE TO
SWING TOWARD THE AREA ON THURSDAY...WITH A COLD FRONT APPROACHING
THE WESTERN ZONES BY THE EVENING HOURS.
DEEP MOISTURE AND PRECIPITABLE WATER VALUES WILL BE HIGHEST
TUESDAY UNDER THE INFLUENCE OF THE LINGERING SHORTWAVE
ENERGY...BEFORE SYNOPTIC SCALE FORCING DIMINISHES A BIT BY
WEDNESDAY. EXPECT SCATTERED COVERAGE OF MAINLY DIURNAL SHOWERS
AND THUNDERSTORMS BOTH TUESDAY AND WEDNESDAY...HIGHEST DURING THE
FAVORED AFTERNOON AND EVENING PERIODS. CONVECTION WILL MAINLY BE
DRIVEN BY A COMBINATION OF DAYTIME HEATING/INSTABILITY...SEABREEZE
CONVERGENCE...AND ANY BOUNDARY INTERACTIONS. WILL THUS ADVERTISE
BEST THUNDERSTORM POTENTIAL ALONG AND INLAND OF THE
SEABREEZE...HOWEVER THERE ARE STILL SOME INDICATIONS THAT
ISOLATED SHOWERS/WEAK THUNDERSTORMS COULD PUSH FROM THE MARINE
ZONES LOCALLY ONSHORE EACH NIGHT AND EARLY MORNING. THE
APPROACHING FRONT COULD SUPPORT BETTER CONVECTIVE COVERAGE ON
THURSDAY...YET PREFER TO MAINTAIN PERSISTENCE BY KEEPING RAIN
CHANCES IN THE 30 PERCENT RANGE TO ACCOUNT FOR SOME TIMING
DIFFERENCES SEEN IN FORECAST MODEL SOLUTIONS.
EXPECT A STEADY WARMING TREND TUESDAY THROUGH THURSDAY. HIGH
TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S FOR THE MAJORITY
OF THE FORECAST AREA ON TUESDAY...WITH THE EXCEPTION OF THE FAR
SOUTHWEST COUNTIES WHERE TEMPERATURES COULD CLIMB INTO THE UPPER
80S. HIGH TEMPERATURES WILL THEN PEAK IN THE UPPER 80S MOST INLAND
LOCATIONS FOR THURSDAY...WHILE BEING SUPPRESSED IN THE LOW TO MID
80S CLOSER TO THE COASTLINE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FAIRLY GOOD MODEL CONSISTENCY REGARDING AN UPPER TROUGH SHIFTING
SOUTHEAST AND A COLD FRONTAL PASSAGE FRIDAY OR FRIDAY NIGHT. DRY AND
SLIGHTLY COOLER CANADIAN HIGH PRESSURE LOOKS TO BUILD IN FOR THE
WEEKEND BEFORE SHIFTING OFFSHORE EARLY NEXT WEEK.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
KCHS...ISOLATED SHOWERS AND BRIEF MVFR CIGS POSSIBLE OVERNIGHT...
OTHERWISE VFR UNTIL DAYBREAK. A RICH TROPICAL-LIKE FEED OF
MOISTURE AND COASTAL CONVERGENCE WILL INTERACT WITH THE SEA BREEZE
DURING THE LATE MORNING AND AFTERNOON HOURS TODAY...PRODUCING
SCATTERED SHRA AND POSSIBLE TSRA. FOR NOW WE MAINTAINED A PROB30
GROUP FOR SHRA AND MVFR CONDITIONS FROM 15-21Z UNTIL TRENDS CAN BE
BETTER DEFINED.
KSAV...WE ANTICIPATE A FEW HOURS OF MVFR CONDITIONS IN LIGHT
LOW STRATUS/STRATOCUMULUS OVERNIGHT AND CONTINUE TO INDICATE THAT
TREND. ISOLATED TO SCATTERED CONVECTION WILL FORM ALONG THE SEA
BREEZE BOUNDARY DURING LATE MORNING THROUGH MID AFTERNOON...THUS
A PROB30 GROUP FROM 16-21Z WAS MAINTAINED.
EXTENDED AVIATION...THE MAIN CONCERN WILL BE SPORADIC REDUCTIONS
IN CEILINGS AND VISIBILITIES...MAINLY ASSOCIATED WITH SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. THE GREATEST CHANCES
WILL BE IN THE AFTERNOON HOURS WED AND THU...ALTHOUGH EARLY MORNING
FLIGHT RESTRICTIONS CANNOT BE RULED OUT EACH DAY.
&&
.MARINE...
TONIGHT...A STRONG RIDGE OF HIGH PRESSURE CENTERED OVER THE
ATLANTIC WILL EXTEND W ACROSS THE COASTAL WATERS...GENERATING SE
AND S WINDS AT OR BELOW 10 OR 12 KT AND SEAS IN THE 2-4 FOOT
RANGE. COULD SEE SOME STRONGER STORMS MOVING IN FROM THE SOUTH
OVERNIGHT.
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH
THURSDAY NIGHT...MAINTAINING A GENERAL SOUTHERLY FLOW AND
ALLOWING SEABREEZE CIRCULATIONS TO DEVELOP EACH AFTERNOON. A COLD
FRONT WILL DROP THROUGH THE REGION EARLY FRIDAY...WITH A NORTHEAST
FLOW DEVELOPING AS CANADIAN HIGH PRESSURE BUILDS IN ITS WAKE.
WINDS AND SEAS WILL LIKELY INCREASE OVER THE WEEKEND AS A RESULT.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...WMS
LONG TERM...JRL
AVIATION...
MARINE...
000
FXUS62 KCAE 210437
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1237 AM EDT TUE MAY 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE ATLANTIC
WILL DOMINATE TODAY. A MOIST SOUTH FLOW IS ASSOCIATED WITH THIS
FEATURE. HIGH LOW-LEVEL MOISTURE AND LIGHT WIND WILL SUPPORT
AT LEAST PATCHY FOG EARLY THIS MORNING. THE MOISTURE PLUS HEATING
SHOULD SUPPORT SCATTERED THUNDERSTORMS THIS AFTERNOON. EXPECT THE
GREATER THUNDERSTORM COVERAGE IN THE EAST PART CLOSER TO THE
TROPICAL PLUME OF MOISTURE SHOWN BY THE WATER VAPOR IMAGERY.
CONVERGENCE ASSOCIATED WITH THE SEA-BREEZE FRONT SHOULD ALSO AID
COVERAGE IN THE EAST PART. SOME CLOUDINESS SHOULD LIMIT
INSTABILITY. THE NAM GENERALLY INDICATES WEAK TO MODERATE
INSTABILITY AND WEAK SHEAR. THE THREAT OF SEVERE THUNDERSTORMS
APPEARS LOW AT THIS TIME. THE GUIDANCE CONSENSUS SUPPORTS HIGHS IN
THE MIDDLE 80S WHICH IS NEAR CLIMATOLOGY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
THE HIGH OFF THE SOUTHEAST COAST WILL CONTINUE TO DOMINATE
THROUGH WEDNESDAY NIGHT. THE MODELS SHOW CONSIDERATE MOISTURE IN
THE SOUTHERLY FLOW ON THE BACKSIDE OF THE OFFSHORE HIGH. EXPECT
SCATTERED THUNDERSTORMS ESPECIALLY DURING THE TIME OF MAXIMUM
HEATING. THE GUIDANCE CONSENSUS SUPPORTS CHANCE POPS. ALSO USED
THE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING COLD FRONT SUPPORTS
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT BUT THE MODELS SHOW
DEEPER MOISTURE SHIFTING FARTHER EASTWARD AHEAD OF THE FRONT. THE
GFS ENSEMBLE MEAN PLUS OPERATIONAL GFS AND ECMWF MOS SUPPORT
CHANCE POPS. THE DRY AIR MASS BEHIND THE FRONT SHOULD DOMINATE
DURING THE REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
SCTD SHOWERS/STORMS HAVE ENDED ACROSS THE AREA WITH MAINLY
CONVECTIVE DEBRIS CLOUDS REMAINING. THESE CLOUDS SHOULD THIN DURING
THE EARLY MORNING HOURS. LOW LEVEL JET IS NOT AS STRONG AND LOW
LEVEL MOISTURE REMAINS PLENTIFUL SO FOG FIGURES TO BE A MORE FAVORED
THREAT. LIGHT TO CALM WINDS OVERNIGHT WILL ALLOW SOME RADIATIONAL
COOLING AND EXPECT SOME FOG TO DEVELOP AFTER 07Z-09Z. WILL INCLUDE
SOME IFR VSBYS AT AGS/OGB AND POSSIBLE THEY COULD OCCUR AT CAE
09Z-12Z. CONFIDENCE IS A LITTLE HIGHER TONIGHT THAN PREVIOUS NIGHTS
BUT GUIDANCE HAS NOT BEEN GREAT AS OF LATE. ANY FOG SHOULD BURN OFF
BY 14Z WITH VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE PERIOD.
WINDS WILL PICK UP OUT OF THE SOUTH TO SOUTHEAST AROUND 5-7 KNOTS.
WIDELY SCTD CONVECTION POSSIBLE LATER THIS AFTERNOON BUT NOT ENOUGH
CONFIDENCE TO MENTION AT ANY OF THE TAF SITES AT THIS TIME. MODEL
DATA SEEMS TO INDICATE THAT BULK OF CONVECTION THAT MAY DEVELOP
LATER THIS AFTERNOON MAY BE EAST OF THE TAF SITES.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KFFC 210211
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1011 PM EDT MON MAY 20 2013
.UPDATE...
OVERALL...FORECAST LOOKS TO BE ON TRACK WITH A FEW MINOR UPDATES.
HAVE MODIFIED TUESDAY POPS SLIGHTLY TO ACCOUNT FOR LATEST MODEL
TRENDS...BUT GENERALLY KEEPING CHANCE AND SLIGHT CHANCE POPS
CONCENTRATED OVER THE EASTERN PORTIONS OF THE CWA. LATEST MODELS
HAVE ALSO SCALED BACK ON LOW LEVEL MOISTURE FOR TUESDAY
MORNING...SO HAVE MADE SOME ADJUSTMENTS TO SKY COVER GRIDS. STILL
EXPECTING PATCHY TO AREAS OF FOG ACROSS LARGE PORTIONS OF THE
AREA AT THIS TIME. NO ADDITIONAL UPDATES ARE PLANNED AT THIS TIME.
31
&&
.PREV DISCUSSION... /ISSUED 814 PM EDT MON MAY 20 2013/
PREV DISCUSSION... /ISSUED 338 PM EDT MON MAY 20 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY/...
MODELS ALL IN GOOD AGREEMENT THROUGH THE SHORT TERM. THE UPPER LOW
THAT BROUGHT THE PRECIP TO THE REGION OVER THE WEEKEND IS SLOW TO
EXIT BUT IT IS DOING SO. SOME LINGERING CONVECTION SOUTH OF THE FALL
LINE WHERE THE CAP IS THE WEAKEST THIS AFTERNOON SHOULD DISSIPATE
AFTER SUNSET. EXPECT ANOTHER AREA OF LOW CLOUDS TUESDAY MORNING
ALONG WITH SOME LIGHT FOG BUT THIS SHOULD DISSIPATE AFTER SUNSET.
THE UPPER RIDGE CONTINUES TO BUILD INTO THE SOUTHEAST
TUESDAY...BECOMING MORE LIKE OUR SUMMER PATTERN WITH AFTERNOON AND
EVENING CONVECTION. ALL MODELS FORECAST PLENTY OF CAPE WITH LITTLE
CIN OVER THE AREA TUESDAY AFTERNOON WITH THE BEST INSTABILITY OVER
THE MOUNTAINS AND THE EASTERN PARTS OF THE CWA. WILL MAINTAIN SLIGHT
CHANCE/CHANCE POPS ACROSS MUCH OF THE CWA TUESDAY AFTERNOON. A
LITTLE MORE SUNSHINE WILL HELP TEMPS PUSH WELL INTO THE 80S WITH
SOME LOWER 90S ACROSS WEST CENTRAL GA ON TUESDAY.
17
LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
NO MAJOR CHANGES MADE TO THE EXTENDED FORECAST. UPPER LEVEL TROUGH
APPROACHING ON WEDNESDAY AND COMBINED WITH ASSOCIATED MOIST AND
INSTABILITY WILL GIVE POTENTIAL FOR NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS ACROSS MAINLY N GA AND MAINLY SCATTERED SHOWERS AND
STORMS FOR CENTRAL GA. A WEAK COLD FRONT GETS INTO THE AREA LATE
THURSDAY...POSSIBILITY ASSOCIATED WITH SOME UPPER LEVEL
SUPPORT...WILL GIVE THE CHANCE FOR SHOWERS AND STORMS. BEST
MOISTURE AND UPPER SUPPORT DRIFTING EAST ON FRIDAY ALLOWING FOR
ONLY A SLIGHT CHANCE OF SHOWERS AND STORMS. OVERALL MOISTURE AND
INSTABILITY APPEAR LACKING SATURDAY INTO MONDAY AND WHILE PRECIP
POTENTIAL IS NOT ZERO IT LOOKS TO BE LESS THAN 20 PERCENT AT THIS
TIME. TEMPERATURES RUNNING WITHIN 5 DEGREES OF NORMAL THROUGH THE
PERIOD.
01
AVIATION...
00Z UPDATE...
CLEARING CONDITIONS EXPECTED THROUGH THE EARLY OVERNIGHT HOURS
BEFORE LOW LEVEL MOISTURE RESULTS IN MVFR CIGS AND RESTRICTED
VSBYS....GENERALLY 09-15Z. CONFIDENCE IS LOW-MEDIUM THAT LOW END
MVFR CIGS WILL DEVELOP IN THE ATL METRO AREA. EXPECT PATCHY TO AREAS
OF FOG...WITH MOST SITES SEEING 3-5SM. EXPECT QUICKLY IMPROVING
CIGS TO SCT CU VFR BY 16-17Z. SSE WINDS EXPECTED OVERNIGHT AT 5KT
OR LESS...WITH SSW EXPECTED BY LATE MORNING. WINDS WILL GRADUALLY
SWITCH BACK AROUND TO THE SSE AGAIN BY 23-00Z TUESDAY EVENING.
ISOLATED TO SCATTERED AFTERNOON CONVECTION EXPECTED ESPECIALLY
ACROSS EASTERN GEORGIA...BUT CHANCES NOT HIGH ENOUGH TO MENTION IN
TAF AT THIS TIME.
//ATL CONFIDENCE...00Z UPDATE...
LOW TO MEDIUM CONFIDENCE ON MVFR CIGS TUESDAY MORNING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 64 87 64 84 / 20 30 30 40
ATLANTA 67 86 67 82 / 10 20 20 50
BLAIRSVILLE 58 83 63 75 / 30 40 40 60
CARTERSVILLE 64 88 66 83 / 10 20 20 60
COLUMBUS 69 92 67 89 / 20 20 20 30
GAINESVILLE 64 85 66 81 / 20 30 40 60
MACON 65 89 64 88 / 30 20 20 30
ROME 63 89 66 82 / 10 10 20 70
PEACHTREE CITY 63 88 63 83 / 10 20 20 50
VIDALIA 68 89 68 87 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....11
AVIATION...31
000
FXUS62 KCAE 210211
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1011 PM EDT MON MAY 20 2013
.SYNOPSIS...
PERSISTENT UPPER LEVEL TROUGH WILL REMAIN OVER THE REGION THROUGH
TUESDAY CONTINUING THE CHANCE OF SHOWERS AND THUNDERSTORMS. A
STRONGER UPPER LEVEL TROUGH WILL CROSS THE CENTRAL US DURING THE
MIDDLE OF THE WEEK AND INTO THE EASTERN US ON FRIDAY RESULTING IN
ADDITIONAL CHANCES OF SHOWERS AND THUNDERSTORMS. DRIER WEATHER IS
EXPECTED BY NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
ISOLATED SHOWER ACROSS PEE DEE OTHERWISE POPS LESS THAN 15 PERCENT
REST OF NIGHT. PATCHY FOG POSSIBLE TOWARD DAYBREAK AS PLENTY OF
MOISTURE WILL BE TRAPPED UNDER THE DEVELOPING INVERSION AND WINDS
WILL BE LIGHT...ALTHOUGH CONSIDERABLE CLOUDINESS EAST WILL LIMIT
FOG. TEMPERATURES WILL GENERALLY BE IN THE MIDDLE 60S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
THE CURRENT WEAK UPPER LEVEL TROUGH THAT HAS PERSISTED ACROSS THE
REGION IS EXPECTED TO REMAIN ACROSS THE SOUTHEAST INTO THURSDAY.
THEN A STRONGER/DEEPER TROUGH WILL PUSH IN FROM THE WEST THURSDAY
AND THURSDAY NIGHT. UNTIL THE MAIN TROUGH PASSES...EXPECT TYPICAL
AFTERNOON SHOWERS AND THUNDERSTORMS TO DEVELOP AND LAST INTO THE
EVENING HOURS BEFORE DISSIPATING. RAIN CHANCES WILL BE MOSTLY
DEPENDENT UPON THE STRENGTH AND MOVEMENT OF THE SEA-BREEZE...ALONG
WITH THE POSITION OF THE UPPER TROUGH. FOR NOW HAVE GENERALLY GOING
WITH CHANCE POPS ACROSS THE FORECAST AREA DURING THE
AFTERNOON/EVENING HOURS. AS FOR TEMPS...WITH A LITTLE MORE
SUNSHINE...EXPECTING HIGHS TO REACH THE MID 80S. OVERNIGHT LOWS IN
THE 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE MAIN UPPER TROUGH WILL BE SWINGING EAST OF THE REGION BY
FRIDAY...WHILE AT THE SURFACE...DRIER HIGH PRESSURE WILL BEGIN
BUILDING BACK INTO THE REGION FROM THE NORTH. UPPER FLOW WILL BE
OUT OF THE NORTHWEST. SURFACE FLOW ALSO OUT OF THE NORTH. THIS
LEADS TO A DRY WEATHER PATTERN AS WE MOVE THROUGH THE WEEKEND.
HIGHS STILL GENERALLY IN THE MID 80S. LOWS WILL BE SLIGHTLY COOLER
WITH READINGS IN THE UPPER 50S TO LOWER 60S.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
ATMOSPHERE IS A LITTLE DRIER TODAY THAN YESTERDAY AND AFTERNOON
CONVECTION HAS SHIFTED SOUTHEAST OF THE TERMINALS. SKIES WILL BE
PARTLY TO MOSTLY CLOUDY THIS EVENING AS CONVECTIVE DEBRIS CLOUDS
REMAIN OVER THE AREA BUT SHOULD THIN LATER TONIGHT. LOW LEVEL JET
IS NOT AS STRONG TONIGHT AND LOW LEVEL MOISTURE REMAINS PLENTIFUL
SO FOG FIGURES TO BE A MORE FAVORED THREAT. LIGHT TO CALM WINDS
OVERNIGHT WILL ALLOW SOME RADIATIONAL COOLING AND EXPECT SOME FOG
TO DEVELOP AFTER 07Z-09Z. WILL INCLUDE SOME IFR VSBYS AT AGS/OGB
AND POSSIBLE THEY COULD OCCUR AT CAE 09Z-12Z. CONFIDENCE IS A
LITTLE HIGHER TONIGHT THAN PREVIOUS NIGHTS BUT GUIDANCE HAS NOT
BEEN GREAT AS OF LATE. ANY FOG SHOULD BURN OFF BY 14Z WITH VFR
CONDITIONS EXPECTED FOR THE REMAINDER OF THE PERIOD. WINDS WILL
PICK UP OUT OF THE SOUTH TO SOUTHEAST AROUND 5-7 KNOTS.
EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND
THUNDERSTORMS...MAINLY AFTERNOON AND EVENING...POSSIBLE THROUGH
FRIDAY. LATE NIGHT/EARLY MORNING FOG/STRATUS ALSO POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 210156
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
956 PM EDT MON MAY 20 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER THE AREA WILL DISSIPATE THROUGH
MID WEEK WHILE ATLANTIC HIGH PRESSURE PREVAILS UNTIL LATE WEEK. A
COLD FRONT WILL DROP THROUGH THE AREA FRIDAY...FOLLOWED BY HIGH
PRESSURE THROUGH NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
ANY LINGERING CONVECTION WEST OF KSAV EARLY TONIGHT WILL DISSIPATE
BEFORE MIDNIGHT WITH THE NOCTURNAL ENVIRONMENT IN PLACE. A NARROW
BUT ELONGATED MID LEVEL IMPULSE WILL LIE OVERHEAD THROUGH THE
NIGHT WITH ITS ASSOCIATED PVA. THAT ALONG WITH LOW LEVEL
CONVERGENCE INCREASING OVER THE ATLANTIC AND NEAR THE SHORELINE
LATE WILL ALLOW FOR A BAND OF SCATTERED CONVECTION TO FORM CLOSE
TO DAYBREAK. WE HAVE LIMITED COVERAGE TO NO MORE THAN 20-30
PERCENT OVER CHARLESTON COUNTY AFTER 4 AM...WITH LITTLE TO NO RISK
ELSEWHERE. PWATS UP NEAR 1.75 INCHES SUGGESTS THAT LOCALLY HEAVY
RAINS CAN OCCUR...ALTHOUGH THE BEST CHANCES REMAINS OUT OVER THE
OCEAN.
CONVECTIVE DEBRIS CLOUDINESS WILL STEADILY DIMINISH IN OPAQUENESS
AND AREAL COVERAGE...BUT WHERE ANY CLEARING SETTLES IN WE LOOK FOR
LOWER STRATUS TO FILL THE VOID. THUS WE HAVE MAINTAINED A MOSTLY
CLOUDY SKY COVER AREA WIDE. GIVEN THE SOUPY AIR MASS...WET GROUNDS
FROM EARLIER RAINS...THE LACK OF WINDS AND FOG STABILITY INDICES
LESS THAN 15 IN MANY LOCALES...FOG WILL BECOME A WEATHER
PHENOMENON. WE/LL CARRY PATCHY COVERAGE AFTER 2 AM INLAND FROM
US-17.
IT/LL BE ANOTHER WARM AND VERY HUMID NIGHT...AND THUS RESTRICTING
LOWEST TEMPS ONLY IN THE MID AND UPPER 60S AWAY FROM THE BEACHES.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ATLANTIC HIGH PRESSURE WILL BE THE DOMINANT FEATURE AT THE SURFACE
TUESDAY AND WEDNESDAY. THE PERSISTENT UPPER SHORTWAVE MEANDERING
OVER THE SOUTHEAST STATES WILL GRADUALLY BECOME ABSORBED BY A TROUGH
AXIS TO THE WEST MID WEEK. THE UPPER TROUGH WILL THEN CONTINUE TO
SWING TOWARD THE AREA ON THURSDAY...WITH A COLD FRONT APPROACHING
THE WESTERN ZONES BY THE EVENING HOURS.
DEEP MOISTURE AND PRECIPITABLE WATER VALUES WILL BE HIGHEST
TUESDAY UNDER THE INFLUENCE OF THE LINGERING SHORTWAVE
ENERGY...BEFORE SYNOPTIC SCALE FORCING DIMINISHES A BIT BY
WEDNESDAY. EXPECT SCATTERED COVERAGE OF MAINLY DIURNAL SHOWERS
AND THUNDERSTORMS BOTH TUESDAY AND WEDNESDAY...HIGHEST DURING THE
FAVORED AFTERNOON AND EVENING PERIODS. CONVECTION WILL MAINLY BE
DRIVEN BY A COMBINATION OF DAYTIME HEATING/INSTABILITY...SEABREEZE
CONVERGENCE...AND ANY BOUNDARY INTERACTIONS. WILL THUS ADVERTISE
BEST THUNDERSTORM POTENTIAL ALONG AND INLAND OF THE
SEABREEZE...HOWEVER THERE ARE STILL SOME INDICATIONS THAT
ISOLATED SHOWERS/WEAK THUNDERSTORMS COULD PUSH FROM THE MARINE
ZONES LOCALLY ONSHORE EACH NIGHT AND EARLY MORNING. THE
APPROACHING FRONT COULD SUPPORT BETTER CONVECTIVE COVERAGE ON
THURSDAY...YET PREFER TO MAINTAIN PERSISTENCE BY KEEPING RAIN
CHANCES IN THE 30 PERCENT RANGE TO ACCOUNT FOR SOME TIMING
DIFFERENCES SEEN IN FORECAST MODEL SOLUTIONS.
EXPECT A STEADY WARMING TREND TUESDAY THROUGH THURSDAY. HIGH
TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S FOR THE MAJORITY
OF THE FORECAST AREA ON TUESDAY...WITH THE EXCEPTION OF THE FAR
SOUTHWEST COUNTIES WHERE TEMPERATURES COULD CLIMB INTO THE UPPER
80S. HIGH TEMPERATURES WILL THEN PEAK IN THE UPPER 80S MOST INLAND
LOCATIONS FOR THURSDAY...WHILE BEING SUPPRESSED IN THE LOW TO MID
80S CLOSER TO THE COASTLINE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FAIRLY GOOD MODEL CONSISTENCY REGARDING AN UPPER TROUGH SHIFTING
SOUTHEAST AND A COLD FRONTAL PASSAGE FRIDAY OR FRIDAY NIGHT. DRY AND
SLIGHTLY COOLER CANADIAN HIGH PRESSURE LOOKS TO BUILD IN FOR THE
WEEKEND BEFORE SHIFTING OFFSHORE EARLY NEXT WEEK.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
KCHS...VFR WEATHER TONIGHT INTO TUESDAY MORNING...UNLESS CLOUDS
THIN OUT ENOUGH THEN THERE WOULD BE A RISK OF LIGHT FOG DEVELOPING.
A RICH TROPICAL-LIKE FEED OF MOISTURE AND COASTAL CONVERGENCE WILL
INTERACT WITH THE SEA BREEZE DURING THE LATE MORNING AND AFTERNOON
HOURS ON TUESDAY...PRODUCING SCATTERED SHRA AND POSSIBLE TSRA. FOR
NOW WE HAVE INCLUDED A PROB30 GROUP FOR SHRA AND MVFR CONDITIONS
FROM 15-21Z UNTIL TRENDS CAN BE BETTER DEFINED.
KSAV...PROVIDED THAT CLOUD COVER DECREASES ENOUGH LATE TONIGHT/TUESDAY
MORNING...WE ANTICIPATE A FEW HOURS OF MVFR CONDITIONS IN LIGHT
FOG/LOW STRATUS. OTHERWISE VFR CONDITIONS TO PREVAIL TONIGHT. ISOLATED
TO SCATTERED CONVECTION WILL FORM ALONG THE SEA BREEZE BOUNDARY
DURING TUESDAY AFTERNOON...THUS A PROB30 GROUP FROM 16-21Z.
EXTENDED AVIATION...THE MAIN CONCERN WILL BE SPORADIC REDUCTIONS
IN CEILINGS AND VISIBILITIES...MAINLY ASSOCIATED WITH SCATTERED
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. THE GREATEST CHANCES
WILL BE IN THE AFTERNOON HOURS WED AND THU...ALTHOUGH EARLY MORNING
FLIGHT RESTRICTIONS CANNOT BE RULED OUT EACH DAY.
&&
.MARINE...
TONIGHT...A STRONG RIDGE OF HIGH PRESSURE CENTERED OVER THE
ATLANTIC WILL EXTEND W ACROSS THE COASTAL WATERS...GENERATING SE
AND S WINDS AT OR BELOW 10 OR 12 KTS AND SEAS IN THE 2-4 FOOT
RANGE. COULD SEE SOME STRONGER STORMS MOVING IN FROM THE SOUTH
OVERNIGHT.
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC THROUGH
THURSDAY NIGHT...MAINTAINING A GENERAL SOUTHERLY FLOW AND
ALLOWING SEABREEZE CIRCULATIONS TO DEVELOP EACH AFTERNOON. A COLD
FRONT WILL DROP THROUGH THE REGION EARLY FRIDAY...WITH A NORTHEAST
FLOW DEVELOPING AS CANADIAN HIGH PRESSURE BUILDS IN ITS WAKE.
WINDS AND SEAS WILL LIKELY INCREASE OVER THE WEEKEND AS A RESULT.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...WMS
LONG TERM...JRL
AVIATION...
MARINE...
| 
