National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS62 KCAE 180700
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
300 AM EDT TUE JUN 18 2013

.SYNOPSIS...
MOISTURE WILL REMAIN HIGH TODAY AND TONIGHT ASSOCIATED WITH A WEST
TO EAST ORIENTED FRONTAL ZONE. THE FRONT WILL BEGIN TO SHIFT A
LITTLE FARTHER SOUTH WEDNESDAY AND MOISTURE WILL DIMINISH
SOMEWHAT.

&&

.NEAR TERM /THROUGH TODAY/...
HIGH MOISTURE WILL CONTINUE TODAY AHEAD OF THE SLOW MOVING FRONT.
CONVERGENCE ASSOCIATED WITH THE FRONT...HEATING...PLUS ANOTHER IN
A SERIES OF MID-LEVEL SHORTWAVE TROUGHS SHOULD SUPPORT NUMEROUS
SHOWERS AND THUNDERSTORMS. THE HIGH RESOLUTION MODELS SUPPORT THE
GREATEST COVERAGE IN THE AFTERNOON. PRECIPITABLE WATER AROUND 2
INCHES AND POSSIBLE TRAINING SUPPORT VERY HEAVY RAIN WITH SOME OF
THE THUNDERSTORMS. CLOUDINESS SHOULD LIMIT INSTABILITY. THE NAM
DISPLAYS SURFACE-BASED LI/S -3 TO -4 TODAY. HOWEVER...BOTH THE NAM
AND ESPECIALLY THE GFS SHOW SIGNIFICANT SHEAR. THE NAM SHOWS H85
WIND INCREASING TO 25 TO 30 KNOTS. THE GFS DISPLAYS 35 TO 40
KNOTS. THE GFS MAY BE OVERDONE...BUT IT HAS SUPPORT FROM THE 12Z
YESTERDAY RUN OF THE ECMWF. HEAVY PRECIPITATION LOADING AND THE
SHEAR SUPPORTS POSSIBLE SEVERE THUNDERSTORMS THIS AFTERNOON.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BECAUSE OF
CLOUDINESS TODAY. USED AN AVERAGE OF THE NAM AND GFS FOR THE WIND
FORECAST.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
CONVERGENCE ASSOCIATED WITH THE SLOW MOVING FRONT SUPPORTS NUMEROUS
SHOWERS AND THUNDERSTORMS TONIGHT. LEANED TOWARD THE HIGHER POP
GUIDANCE. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING WILL
SUPPORT VERY HEAVY RAIN WITH SOME OF THE THUNDERSTORMS.
SIGNIFICANT SHEAR MAY ALSO SUPPORT ORGANIZED THUNDERSTORMS WITH
DAMAGING WIND POSSIBLE. THE THREAT OF SEVERE THUNDERSTORMS SHOULD
DIMINISH LATE BECAUSE OF DIMINISHED INSTABILITY ASSOCIATED WITH
PREVIOUS CONVECTION AND NOCTURNAL COOLING. THE NAM AND GFS KEEP
THE FRONT NEAR THE FORECAST AREA WEDNESDAY AND WEDNESDAY NIGHT BUT
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA. THE GFS MOS
INDICATED LOWER POPS COMPARED TO THE NAM AND MAY BE CORRECT
BECAUSE OF THE DIMINISHED MOISTURE AND WIDESPREAD CONVECTION THAT
SHOULD HAVE OCCURRED EARLIER. HOWEVER...BASED ON THE FRONT
LINGERING IN THE AREA AND ANOTHER MID-LEVEL SHORTWAVE TROUGH WE
MAINTAINED CHANCE POPS. THE TEMPERATURE GUIDANCE WAS CLOSE.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
THE GFS AND ECMWF GENERALLY SHOWED AN ONSHORE FLOW INTO THE
FORECAST AREA ASSOCIATED WITH HIGH PRESSURE CENTERED OFF THE
MIDDLE ATLANTIC COAST. THERE MAY BE A WEAKNESS IN THE UPPER
RIDGING DURING MUCH OF THE PERIOD. EXPECT SCATTERED MAINLY DIURNAL
THUNDERSTORMS WITH TEMPERATURES NEAR CLIMATOLOGY. THE GFS AND
ECMWF MOS PLUS GFS ENSEMBLE MEANS SUPPORT CHANCE POPS AND NORMAL
TEMPERATURES.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
CONVECTIVE ACTIVITY HAS DIMINISHED. EXPECT MOST CONVECTIVE
ACTIVITY TO DISSIPATE DURING THE EARLY MORNING HOURS AFTER AN
UPPER DISTURBANCE MOVES THROUGH. CONCERN WILL THEN SHIFT TO ANY
FOG/STRATUS POTENTIAL. RAINFALL HAS OCCURRED AT ALL THE TERMINALS
AND CURRENT DEWPOINT DEPRESSIONS LOW. HOWEVER...LATEST CAE VAD
WIND PROFILE INDICATING A SW 25 KT LOW LEVEL JET...AND SATELLITE
SUGGESTS CONSIDERABLE UPPER LEVEL CONVECTIVE DEBRIS CLOUD COVER
COULD LINGER...WHICH WOULD WORK AGAINST FOG FORMATION. LATEST HIGH
RES MODEL GUIDANCE SUGGESTING LOWER CLOUDS POSSIBLE WITH MVFR TO
IFR CIGS. FOR NOW...WILL INDICATE PERIOD OF MVFR CONDITIONS LATE
TONIGHT/EARLY TUESDAY MORNING.

AFTER ANY MORNING RESTRICTIONS...EXPECT VFR TUESDAY OUTSIDE OF
SCATTERED TO POSSIBLY NUMEROUS MAINLY AFTERNOON/EVENING
THUNDERSTORMS.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$