Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 060624
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
124 AM EST SAT FEB 6 2016

.SYNOPSIS...
HIGH PRESSURE OVER THE MISSISSIPPI RIVER VALLEY WILL BUILD EAST
INTO THE AREA TONIGHT AND SATURDAY. LOW PRESSURE WILL DEVELOP OFF
THE SOUTHEAST COAST SATURDAY NIGHT AND PULL FARTHER AWAY FROM THE
AREA SUNDAY NIGHT. MOST OF THE PRECIPITATION ASSOCIATED WITH THE
LOW IS EXPECTED TO REMAIN EAST OF THE FORECAST AREA.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
STRONG NET RADIATIONAL COOLING WILL OCCUR TONIGHT. THE LOCAL
RADIATION TECHNIQUE AND GUIDANCE CONSENSUS SUPPORT LOWS IN THE
MIDDLE 20S TO NEAR 30. EXPECT JUST THIN UPPER CLOUDINESS AHEAD OF
AN UPPER TROUGH.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
SURFACE HIGH PRESSURE WILL REMAIN ANCHORED OVER THE FORECAST AREA
THROUGH THE WEEKEND WHILE ANOTHER POSITIVELY TILTED...HIGHLY
AMPLIFIED UPPER TROUGH MOVES INTO THE REGION SATURDAY NIGHT AND
CROSSES THE FORECAST AREA AS A CLOSED LOW SUNDAY. THE APPROACHING
UPPER TROUGH WILL INDUCE STRONG CYCLOGENESIS OFF THE SOUTHEAST
COAST FROM LATE SATURDAY AFTERNOON THROUGH SATURDAY NIGHT AND
THEN THE LOW WILL BEGIN TO LIFT NORTHEAST AWAY FROM THE REGION
SUNDAY. THE LATEST GFS AND ECMWF WERE REASONABLY CLOSE WITH
PLACEMENT OF THE SURFACE LOW OFF THE CAROLINA COAST ALTHOUGH THE GFS
MAY BE JUST A BIT FARTHER TO THE WEST.

ATMOSPHERIC MOISTURE WILL REMAIN QUITE LOW WITH ONLY THE EASTERN
MIDLANDS SEEING PRECIPITABLE WATER VALUES RISE ABOVE 0.25 OF AN
INCH TO AS HIGH AS 0.60 OF AN INCH LATE SATURDAY NIGHT INTO EARLY
SUNDAY MORNING. ISENTROPIC LIFT WILL INCREASE ALONG THE COAST AND
EXPECT LIGHT RAIN TO DEVELOP AND LIFT NORTHWARD...POSSIBLY
IMPACTING MAINLY THE EASTERN MIDLANDS SATURDAY NIGHT INTO SUNDAY.
WILL CONTINUE TO CARRY LOW CHANCE POPS AT THIS TIME. THE NAM WAS A
LITTLE COOLER COMPARED TO THE GFS INDICATING A GREATER CHANCE OF
SNOW. SOME SREF MEMBERS INDICATED SNOW. THE CONSENSUS INDICATES
LIGHT AMOUNTS AND MARGINAL TEMPERATURES. WE HAVE FORECASTED A
SLIGHT CHANCE OF A RAIN AND SNOW MIX LATE SATURDAY NIGHT INTO
SUNDAY MORNING IN THE EAST PART OF THE FORECAST AREA.

THE UPPER LOW WILL PUSH OFF THE COAST SUNDAY AFTERNOON WITH ZONAL
FLOW RESUMING OVER THE REGION. TEMPERATURES WILL BE BELOW NORMAL
THIS PERIOD. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FORECAST.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
A DEEP AND EXPANSIVE UPPER TROUGH WILL SINK SOUTHEASTWARD INTO
THE OHIO VALLEY AND TAKE RESIDENCE OVER MUCH OF THE EASTERN PART
OF THE COUNTRY THROUGH MID WEEK. SEVERAL WAVES OF VORTICITY MOVING
THROUGH THE TROUGH WILL APPROACH THE REGION MONDAY THROUGH
WEDNESDAY BUT THE STRONGEST OF THEM WILL ARRIVE MONDAY AFTERNOON.
THIS WILL COINCIDE WITH VERY STRONG HEIGHT FALLS AND STEEP LAPSE
RATES AS 500 MB TEMPS FALL TO -25C TO -29 C. ATMOSPHERIC MOISTURE
WILL NOT BE OVERLY GREAT BUT PRECIPITABLE WATER VALUES WILL
INCREASE TO NEAR 0.50 OF AN INCH AND BE SUFFICIENT TO SUPPORT
SOME DIURNAL SHOWERS. MODEL SOUNDINGS AND BUFKIT P-TYPE TABLES
PLUS METEOGRAMS INDICATE THE PREDOMINATE PRECIPITATION TYPE WOULD
BE ALL RAIN ACROSS THE FORECAST AREA...ALTHOUGH THE CLT BUFKIT
SOUNDING WAS INDICATING A POSSIBLE RAIN/SNOW MIX. SO IT CANNOT BE
TOTALLY RULED OUT THAT THERE COULD BE A POSSIBLE MIX OF SOME SNOW
WITH THE RAIN ACROSS THE NORTHERN PART OF THE FORECAST AREA BY
MONDAY EVENING AS COOLER AIR ARRIVES. WILL CARRY LOW CHANCE POPS
AT THIS POINT WITH RAIN AS THE PRECIPITATION TYPE.

MONDAY NIGHT THE LOW-LEVEL FLOW BECOMES NORTHWESTERLY AND
PROVIDES A DOWNSLOPING COMPONENT WHICH WOULD INHIBIT PRECIPITATION
MAKING IT INTO THE FORECAST AREA. A MUCH COLDER AIR MASS WILL
BUILD INTO THE AREA MONDAY NIGHT WITH STRONG COLD ADVECTION
OCCURRING AND 850 MB TEMPERATURES FALLING TO -6 TO -8 C BY
TUESDAY MORNING. THE UPPER FLOW REMAINS NORTHWESTERLY THROUGHOUT
THE REMAINDER OF THE MEDIUM-RANGE PERIOD WITH PERIODIC
DISTURBANCES MOVING THROUGH THE FLOW BUT HAVING LITTLE IMPACT ON
OUR WEATHER BECAUSE OF DOWNSLOPING AND THE LACK OF MOISTURE.
TEMPERATURES DURING THIS PERIOD WILL BE QUITE COOL AND WELL BELOW
NORMAL WITH HIGHS IN THE 40S AND LOWS IN THE 20S. TEMPERATURES
MODERATE A BIT FRIDAY WITH HIGHS IN THE 50S AND LOWS THURSDAY
NIGHT AROUND 30.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...

VFR CONDITIONS EXPECTED THROUGH THIS AFTERNOON.

SURFACE HIGH PRESSURE CURRENTLY OVER THE REGION. DRY LOW LEVEL AIR
IN PLACE. FRIDAY AFTERNOON CROSSOVER TEMPS/DEWPOINTS WERE GENERALLY
IN THE TEENS...PRECLUDING FOG CONCERNS TONIGHT DESPITE MOSTLY CLEAR
SKIES AND LIGHT WINDS. SATELLITE INDICATING SOME THIN HIGH LEVEL
CLOUDINESS WILL STREAM IN OVERNIGHT. STRONG UPPER TROUGH CURRENTLY
OVER THE CENTRAL CONUS WILL DIVE INTO THE SE CONUS TONIGHT. STRONG
UPPER LIFT AND DIVERGENCE OVER TOP OF LOW LEVEL BAROCLINIC ZONES
ASSOCIATED WITH OLD FRONTAL BOUNDARY AND THE GULF STREAM ALLOWS A
LOW PRESSURE AREA TO BEGIN DEVELOPING OFFSHORE LATE TODAY AND THIS
EVENING WHICH IS EXPECTED TO RAPIDLY INTENSIFY AND SHIFT NE. MODEL
CONSENSUS HAS MOISTURE SHIFTING NORTH INTO MAINLY THE SOUTHERN AND
EASTERN PORTIONS OF OUR FORECAST AREA THIS EVENING AND TONIGHT. THIS
WILL FAVOR BETTER PRECIPITATION CHANCES AND ASSOCIATED RESTRICTIONS
AT OGB AND POINTS TO THE SOUTH AND EAST OF THERE. FOR NOW...WILL
INTRODUCE RAIN AND MVFR CONDITIONS AT OGB THIS EVENING. JUST BEYOND
THE CURRENT TAF PERIOD FOR LATE SATURDAY NIGHT INTO EARLY SUNDAY
MORNING...THERE IS THE PREMISE FOR BETTER PRECIP CHANCES AND SOME
LOWER RESTRICTIONS AND A RAIN/SNOW MIX...MAINLY AT OGB. CURRENT
INDICATIONS ARE THAT LOW LEVEL AND SURFACE TEMPS WILL BE WARM ENOUGH
THAT IF SNOW FELL IT WOULD MELT WITHOUT SIGNIFICANT ACCUMULATION.

EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE SAT NT/SUNDAY
MORNING...FAVORING OGB.  A COLD FRONT WILL MOVE THROUGH MONDAY WITH
A SLIGHT CHANCE OF SHOWERS AND POSSIBLE RESTRICTIONS. BREEZY
CONDITIONS POSSIBLE AT TIMES MON THRU WED.

&&

.HYDROLOGY...
MANY RIVERS STILL REMAIN HIGH ACROSS THE AREA DUE TO HEAVY
RAINFALL OVER THE PAST 48 HOURS. MINOR FLOODING CONTINUES ON THE
CONGAREE RIVER AT CAROLINA EASTMAN AND FOR THE NORTH FORK OF THE
EDISTO RIVER AT ORANGEBURG. BOTH RIVERS ARE EXPECTED TO GRADUALLY
FALL BELOW FLOOD STAGE SATURDAY NIGHT THROUGH SUNDAY.

&&

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

&&

$$



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