Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 030118
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
918 PM EDT MON MAY 2 2016

.SYNOPSIS...
A MOIST SOUTHERLY FLOW WILL CONTINUE INTO THE FORECAST AREA
THROUGH TONIGHT AHEAD OF A SLOW MOVING COLD FRONT. THE FRONT WILL
BE IN THE FORECAST AREA TUESDAY AND TUESDAY NIGHT. DRYING WILL
OCCUR BEHIND THE FRONT WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
MOST CONVECTION OVER OUR FORECAST AREA (FA) IN THE PROCESS OF
WEAKENING/DISSIPATING...EXCEPT FOR SOME ACTIVITY OVER THE CSRA
WHERE INSTABILITIES ARE HIGHER. FARTHER WEST...CONVECTION
DEVELOPING OVER CENT GA AHEAD OF AN UPPER DISTURBANCE...AND
ASSOCIATED BAND OF CONVECTIVE ACTIIVTY CURRENTLY TO OUR WEST
STRETCHING ACROSS N GA INTO ALA. ARRAY OF HIGH RESOLUTION MODELS
CONSISTENT WITH INDICATING THIS ACTIVITY MOVING EAST AND
TRAVERSING OUR FA TONIGHT MAINLY 04Z- 08Z. SO...HAVE TRENDED POPS
ACCORDINGLY.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
DIGGING UPPER LEVEL TROUGH WILL STRETCH FROM THE GREAT LAKES TO
THE CENTRAL PLAINS. THIS FEATURE WILL DIG SOUTH AND EASTWARD AS
IT MOVES APPROACHES THE AREA BY WEDNESDAY. AT THE SURFACE...A COLD
FRONT WILL APPROACH FROM THE WEST ON TUESDAY. THE FRONT WILL
GRADUALLY PUSH ACROSS THE AREA TUESDAY NIGHT AND OFF THE COAST BY
WEDNESDAY. A REINFORCING COLD FRONT ASSOCIATED WITH STRONGER UPPER
LEVEL CLOSED LOW WILL PASS ACROSS THE AREA WEDNESDAY NIGHT. THE
BEST CHANCE OF SHOWERS/THUNDERSTORMS IN THE SHORT TERM PERIOD WILL
CONTINUE TO BE ALONG/AHEAD OF THE COLD FRONT TUESDAY THROUGH
TUESDAY NIGHT. CONVERGENCE ASSOCIATED WITH THE COLD FRONT IN THE
AREA PLUS THE DEEPENING UPPER TROUGH SUPPORTS SHOWERS AND
THUNDERSTORMS. HOWEVER...COVERAGE MAY BE LIMITED AS ALL OF THE
MODELS INDICATE THAT THE DEEPEST MOISTURE WILL BEGIN TO MOVE
NORTHEAST OF THE CWA EARLY TUESDAY. THE GUIDANCE CONSENSUS
SUPPORTS CHANCE POPS. COOLING ALOFT ASSOCIATED WITH THE DEEPENING
UPPER TROUGH MAY HELP CAUSE MODERATE INSTABILITY TUESDAY INTO
TUESDAY NIGHT. THIS WILL INCREASE THE CHANCES FOR THE POSSIBILITY
OF SOME HAIL WITH THE STRONGER STORMS. BOTH THE NAM/GFS SHOW
TOTALS VALUES IN THE MID/UPPER 40S/NEAR 50 TUESDAY. THE STRONGER
THUNDERSTORMS COULD PRODUCED DAMAGING WIND AND HAIL. BELIEVE THESE
STORMS WILL BE WIDELY SCATTERED BUT POTENTIAL EXIST. GUIDANCE POPS
HAVE BEEN RATHER CONSISTENT FOR CHANCE/HIGH CHANCE POPS ON TUESDAY
WITH LOWER POPS FOR TUESDAY NIGHT WITH A CONTINUAL DECLINE INTO
WEDNESDAY/WED NIGHT. TEMPERATURES ALSO HAVE BEEN CONSISTENT OVER
THE PAST SEVERAL MODEL RUNS AND HAVE STAYED WITH CONSENSUS.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
THE GFS/ECMWF ARE IN GENERAL AGREEMENT THAT AN UNUSUALLY STRONG
UPPER LEVEL CLOSED LOW WILL DIVE SOUTHEASTWARD OVER THE
CAROLINAS/VIRGINIA THURSDAY AND FRIDAY. THE CLOSED LOW WILL
CONTINUE TO MOVE EAST/NORTHEAST OFF THE MID-ATLANTIC COAST BY THE
WEEKEND. THIS WILL SUPPORT A CHANCE OF A SHOWER/ISOLATED
THUNDERSTORM ALONG THE NC/SC BORDER. MODELS DO DIFFER ON HOW FAR
SOUTHWARD CLOSED LOW WILL PROGRESS. VERY COLD AIR ALOFT WITH H5
TEMPERATURES RANGING FROM -20 C TO -25 C COULD HELP SUPPORT LOW-
TOPPED CONVECTION WITH GRAUPEL OR SMALL HAIL MAINLY THURSDAY. THIS
COULD BE A FACTOR FRIDAY...JUST DEPENDS ON SPEED AND POSITION OF
CLOSED LOW. THE GFS...ECMWF...AND EKD MOS INDICATE TEMPERATURES
MUCH BELOW NORMAL THURSDAY AND FRIDAY...AND MODERATION BEGINNING
SATURDAY THEN RISING TO AT/ABOVE NORMAL BY SUNDAY/MONDAY.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
MOST CONVECTION OVER OUR FORECAST AREA (FA) IN THE PROCESS OF
WEAKENING/DISSIPATING...EXCEPT FOR SOME ACTIVITY OVER THE CSRA
NEAR DNL/AGS WHERE INSTABILITIES ARE HIGHER. FARTHER
WEST...CONVECTION DEVELOPING OVER CENT GA AHEAD OF AN UPPER
DISTURBANCE...AND ASSOCIATED BAND OF CONVECTIVE ACTIIVTY CURRENTLY
TO OUR WEST STRETCHING ACROSS N GA INTO ALA. ARRAY OF HIGH
RESOLUTION MODELS CONSISTENT WITH INDICATING THIS ACTIVITY MOVING
EAST AND TRAVERSING OUR FA TONIGHT MAINLY 04Z- 08Z.

WILL CONCENTRATE ON THE NEAR TERM AND HANDLE CONVECTIVE ACTIVITY AS
APPROPRIATE BASED ON RADAR TRENDS AND CONFIDENCE LEVEL. MVFR TO
IFR CONDITIONS POSSIBLE AT TIMES WITH THE CONVECTIVE
ACTIVITY...AND THEN MORE WIDESPREAD LOWER CLOUDINESS WITH MVFR
CIGS POSSIBLE LATE TONIGHT INTO EARLY TUESDAY MORNING.

ADDITIONAL CONVECTION EXPECTED TUESDAY AFTN/EVE. WILL HANDLE WITH
VCTS FOR NOW.

EXTENDED AVIATION OUTLOOK...MVFR RESTRICTIONS IN LOW CLOUDINESS
POSSIBLE LATE TUE NT INTO EARLY WED MORNING. CHANCE OF
SHOWERS/ISOLATED THUNDERSTORMS THURSDAY. VFR EXPECTED FRI/SAT.

&&

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

&&

$$



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