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.
&&

$$