Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 291826
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
226 PM EDT MON JUN 29 2015

.SYNOPSIS...
A DRIER AIR MASS WILL SPREAD ACROSS THE AREA TODAY. CONDITIONS
REMAIN DRY THROUGH TONIGHT WITH CHANCES OF AFTERNOON AND EVENING
THUNDERSTORMS RETURNING FOR TUESDAY THROUGH THE REST OF THE
WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
A LONGWAVE UPPER TROUGH REMAINS CENTERED OVER THE GREAT LAKES REGION
THIS AFTERNOON WITH HIGH PRESSURE BUILDING IN OVER THE FORECAST AREA
AT THE SURFACE. MUCH DRIER AIR THAN IN RECENT DAYS IS IN PLACE WITH
PWAT VALUES GENERALLY BELOW AN INCH AND DEWPOINTS IN THE MIDDLE 50S.
MODEL FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW A CAP WHICH SHOULD
PREVENT ANY DIURNAL CONVECTION. TEMPERATURES ARE EXPECTED TO TOP OUT
NEAR NORMAL...IN THE LOWER 90S. OVERNIGHT LOWS ARE FORECAST IN THE
UPPER 60S TO NEAR 70.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
THE UPPER LEVEL TROUGH AMPLIFIES TUESDAY AND SHIFTS SLIGHTLY
EASTWARD. THE FA WILL LIE UNDER THE RIGHT ENTRANCE REGION OF THE
JET ALLOWING FOR UPPER LEVEL DIVERGENCE AND SYNOPTIC SCALE LIFT.
BOTH THE NAM AND GFS INDICATE SHORTWAVES MOVING ACROSS THE
SOUTHEAST TUESDAY AFTERNOON.

THERE IS SOME DISAGREEMENT BETWEEN MODELS ON THE TIMING OF THE
MAIN VORTICITY LOBE AND SURFACE DEWPOINTS. THE GFS IS DRIER AND
BRINGS THE SHORTWAVE NEAR THE FA TUESDAY EVENING. THE NAM IS MORE
FAVORABLE FOR AFTERNOON CONVECTION WITH GREATER LOWER LEVEL
MOISTURE. IT ALSO PLACES THE SHORTWAVE SW OF THE FA IN THE
AFTERNOON WHICH COULD TRIGGER STORMS AT THE TIME OF PEAK HEATING.
NAM LI VALUES RANGE FROM -5 TO -7 TUESDAY AFTERNOON WHILE THE GFS
IS MORE MODEST. BOTH MODELS INDICATE DEEP LAYER SHEAR VALUES FROM
20 TO 25 KTS SUGGESTING A STORM STRUCTURE THAT IS MORE ORGANIZED
THAN TYPICAL SUMMERTIME CELLS. HI RES MODELS TEND TO FAVOR THE
NAM...PRODUCING MULTICELL CLUSTERS MOVING FROM THE WEST INTO THE
CWA BY LATE AFTERNOON.

SCATTERED THUNDERSTORMS ARE POSSIBLE TUESDAY AFTERNOON INTO THE
EVENING. WITH A LARGE SPREAD IN INSTABILITY AND MOISTURE IT IS
UNCERTAIN WHETHER CONVECTION WILL BE WIDESPREAD.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THE UPPER LEVEL TROUGH WILL PERSIST THROUGH THE WEEK BECOMING
MORE ZONAL THIS WEEKEND. THE WEATHER RETURNS TO A MORE TYPICAL
SUMMERTIME REGIME FOR THE REMAINDER OF THE WEEK INTO THE WEEKEND
WITH DIURNAL AFTERNOON CONVECTION. MODELS INDICATE STRONG MOISTURE
ADVECTION OVER THE FA THURSDAY AS LOW PRESSURE MOVES INTO THE MID
ATLANTIC STATES. SOUTHERLY FLOW AND STRONG MOISTURE ADVECTION MAY
ALLOW FOR WIDESPREAD AFTERNOON CONVECTION. TEMPERATURES WILL
GRADUALLY WARM THROUGH THE PERIOD WITH MAX TEMPS IN THE LOWER 90S
ON WED AND THU...MID 90S FRI THRU MON.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED THROUGHOUT THE TAF PERIOD.

HIGH PRESSURE AND A DRY AIRMASS SHOULD PREVENT CONVECTIVE ACTIVITY
THIS AFTERNOON AND EVENING. VISIBLE SATELLITE IMAGERY SHOWING SOME
FAIR WEATHER CUMULUS AND CIRRUS OVER THE TERMINALS. A 20-KT
NOCTURNAL LOW LEVEL JET AND LIMITED MOISTURE NEAR THE SURFACE SHOULD
PRECLUDE FOG DEVELOPMENT TUESDAY MORNING. SOME FOG WAS OBSERVED AT
FOG PRONE AGS/OGB LAST NIGHT AND CANNOT BE RULED OUT TONIGHT
ALTHOUGH CONFIDENCE IS TOO LOW TO INCLUDE. WINDS WILL GENERALLY BE
OUT OF THE WEST AT AROUND 10 TO 12 KNOTS WITH GUSTS UP TO 18 KNOTS
AND WILL BECOME LIGHT THIS EVENING.

SHORTWAVE ENERGY AND INCREASING MOISTURE WILL PROMOTE A CHANCE OF
DIURNAL CONVECTION ON TUESDAY WITH THE BEST CHANCE MAINLY AFTER THE
END OF THE 24-HR TAF PERIOD. CONFIDENCE IN TIMING AND COVERAGE IS
TOO LOW TO INCLUDE IN TAFS AT THIS TIME. WINDS WILL PICK UP OUT OF
THE SOUTHWEST BY 15Z TUESDAY AT AROUND 10 TO 12 KNOTS.

EXTENDED AVIATION OUTLOOK...INCREASING CHANCES OF RESTRICTIONS
TUESDAY THROUGH FRIDAY IN MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS.

&&

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

&&

$$
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