Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 301228
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
828 AM EDT SAT APR 30 2016

.SYNOPSIS...
A STATIONARY FRONT NEAR THE NORTH AND SOUTH CAROLINA BORDER TODAY
WILL LIFT NORTH AS A WARM FRONT TONIGHT. A MOIST SOUTHERLY FLOW
WILL OCCUR INTO THE FORECAST AREA THROUGH SUNDAY. A SLOW MOVING
COLD FRONT WILL NEAR THE REGION MONDAY. AN AREA OF LOW PRESSURE
WILL LIKELY DEVELOP ALONG THE FRONT NEAR THE FORECAST AREA
TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE NAM AND GFS DISPLAY A STATIONARY FRONT NEAR THE NORTH AND
SOUTH CAROLINA BORDER TODAY RETREATING NORTHWARD AS A WARM FRONT
TONIGHT. SOUTH OF THE FRONT...MOISTURE HAS INCREASED IN THE LOW-
LEVEL SOUTHEAST FLOW INTO THE FORECAST AREA. SATELLITE TRENDS
AND OBSERVATIONS INDICATE STRATUS AND FOG HAVE OVERSPREAD MUCH OF
THE AREA EARLY THIS MORNING...ESPECIALLY THE SOUTHEAST SECTION
WHERE LOW-LEVEL MOISTURE WAS GREATEST. WE HAVE ISSUED A DENSE FOG
ADVISORY FOR THE SOUTHEAST PART. HEATING AND MIXING SHOULD
DISSIPATE THE FOG AND LEAD TO BREAKS IN THE STRATUS LATER THIS
MORNING. HEATING AND THE MOISTURE INCREASE SHOULD HELP CAUSE
AFTERNOON THUNDERSTORMS BUT LINGERING H5 RIDGING SHOULD LIMIT
COVERAGE. THE HRRR AND ARW DISPLAYED SCATTERED COVERAGE MAINLY IN
THE NORTHWEST SECTION CLOSER TO DEEPER MOISTURE AND CONVERGENCE
NEAR THE FRONT. SHOWER AND THUNDERSTORM COVERAGE MAY INCREASE
TONIGHT AHEAD OF A MID- LEVEL SHORTWAVE TROUGH. THERE WAS HIGH
SPREAD IN THE GUIDANCE POPS. WE FORECASTED CHANCE POPS BECAUSE OF
NOCTURNAL COOLING AND THE INCONSISTENT GUIDANCE. THE NAM INDICATED
SURFACE-BASED LI/S ABOUT -7 AND TOTAL TOTALS AROUND 51. THE
MODERATE INSTABILITY INDICATES POSSIBLE DAMAGING WIND WITH THE
THUNDERSTORMS THIS AFTERNOON AND EVENING. WET BULB ZERO HEIGHTS
FAVOR HAIL. LEANED TOWARD THE HIGHER TEMPERATURE GUIDANCE TODAY
SOUTH OF THE FRONT. THE TEMPERATURE GUIDANCE WAS CLOSE TONIGHT.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE MODELS CONTINUED TO DISPLAY HIGH MOISTURE IN THE SOUTHERLY
FLOW AHEAD OF THE SLOWLY APPROACHING COLD FRONT. THE MODELS
DEPICTED WEAK H85 WARM ADVECTION. THERE SHOULD BE CONSIDERABLE
CLOUDINESS. A WELL DEFINED MID-LEVEL FEATURE WAS NOT INDICATED.
FOLLOWED THE GUIDANCE CONSENSUS AND FORECASTED CHANCE POPS. THE
TEMPERATURE GUIDANCE WAS CLOSE.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
THE GFS AND ECMWF DISPLAYED INCREASED MOISTURE AHEAD OF A SLOW
MOVING COLD FRONT MONDAY. THERE HAS NOT BEEN CONSISTENCY WITH THE
PLACEMENT OF DEEPEST MOISTURE OR A WAVE FORECAST TO DEVELOP ALONG
THE FRONT TUESDAY THROUGH THURSDAY. THE MODELS ALSO WERE NOT
CONSISTENT WITH THE POSITION OF AN H5 CUT-OFF LOW FRIDAY. THE GFS
AND ECMWF MOS HAVE MAINLY INDICATED HIGHEST POPS MONDAY NIGHT OR
TUESDAY WITH THE FORECAST AREA POSITIONED UNDER THE RIGHT ENTRANCE
REGION OF AN H25 JET. THE GFS...ECMWF...AND EKD MOS HAD
TEMPERATURE ABOVE NORMAL AHEAD OF THE FRONT MONDAY. THE MOS
TEMPERATURES WERE NEAR NORMAL TUESDAY AND WEDNESDAY...AND BELOW
NORMAL THURSDAY AND FRIDAY.

&&

.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
HIGH CONFIDENCE IN LIFR/IFR CONDITIONS THROUGH 14Z.

STRATUS AND FOG DEVELOPMENT HAS SPREAD OVER ALL TERMINALS THIS
MORNING WITH VSBYS AS LOW AS 1/4SM AND CIGS AROUND 200-300 FT.
EXPECT RESTRICTIONS TO SLOWLY IMPROVE THROUGH 14Z THEN BECOME VFR
AS MIXING AND DAYTIME HEATING ERODE THE FOG/STRATUS.
UPPER RIDGE AXIS REMAINS OVER THE AREA BUT ABUNDANT LOW LEVEL
MOISTURE IN PLACE COMBINED WITH DAYTIME HEATING WILL RESULT IN ISOLATED
TO SCATTERED CONVECTION THIS AFTERNOON. BEST COVERAGE IS EXPECTED
TO BE NORTHWEST OF THE TERMINALS SO CONFIDENCE IS TOO LOW TO
INCLUDE IN TAFS AT THIS TIME. SOME IFR CIGS POSSIBLE AFTER 04Z
SUNDAY AS AN UPPER LEVEL SHORTWAVE APPROACHES. SHOWERS MAY ALSO
BE POSSIBLE AT AGS/DNL/CAE BY THAT TIME AS WELL.

EXTENDED AVIATION OUTLOOK...SCATTERED AFTERNOON/EVENING CONVECTION
COULD CAUSE SOME TEMPORARY RESTRICTIONS THROUGH MONDAY. EARLY
MORNING LOW CIGS LOOK POSSIBLE AT ALL THE TERMINALS SUNDAY/MONDAY
MORNING WITH MOISTURE INCREASING AND LOW LEVEL WINDS REMAINING
LIGHT. BETTER CHANCES FOR CONVECTIVELY INDUCED MVFR/IFR CONDITIONS
SEEM TO BE IN LINE FOR TUESDAY.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR SCZ022-
     027>031-035>038-041.

&&

$$

AVIATION...HC



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