Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 142358
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
658 PM EST SUN FEB 14 2016

.SYNOPSIS...
A SURFACE RIDGE EXTENDING THROUGH THE FORECAST WILL SHIFT OFF THE
COAST TONIGHT. A WARM FRONT WILL DEVELOP SOUTH OF THE FORECAST
AREA TONIGHT. THE FRONT WILL LIFT NORTHWARD AND INTO THE AREA
MONDAY AHEAD OF A COLD FRONT. THE COLD FRONT WILL MOVE THROUGH THE
REGION LATE MONDAY NIGHT AND EARLY TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
COLD AND DRY HIGH PRESSURE CENTERED OVER NEW ENGLAND CONTINUES TO
RIDGE INTO THE SOUTHEASTERN STATES. CLOUDS EXPECTED TO CONTINUE
TO INCREASE THROUGH THE NIGHT AS LOW LEVEL FLOW BECOMES MORE
SOUTHEASTERLY OFF THE ATLANTIC...AND WEAK ISENTROPIC UPGLIDE
OVERSPREADS THE COLD DOME OF HIGH PRESSURE IN PLACE. THE CLOUD
COVER WILL ACTUALLY HELP TEMPERATURES REMAIN SOMEWHAT STEADY
OVERNIGHT ALTHOUGH PERSISTENT NORTHEASTERLY FLOW WILL USHER IN
SOME COOLER AIR ACROSS THE NORTHERN MIDLANDS AS AN IN SITU COLD
AIR DAMMING WEDGE DEVELOPS. MOISTURE WILL REMAIN VERY SHALLOW IN
THE LOWEST 4000-5000FT WITH DRY AIR ALOFT AND NO MOISTURE IN THE
SNOW GROWTH AREA. NO DYNAMICAL FORCING OVERNIGHT WITH THE ONLY
LIFT OCCURRING FROM ISENTROPIC UPGLIDE. THINK MUCH OF ANY
PRECIPITATION OVERNIGHT WILL FALL AS VIRGA AND GO INTO SATURATING
THE NEAR SURFACE LAYER WITH LITTLE IF ANY REACHING THE GROUND.
POPS INCREASE AFTER 06Z INTO THE CHANCE RANGE BY EARLY MORNING AND
SOUNDINGS INDICATE PREDOMINATE PTYPE WOULD BE FREEZING
RAIN/DRIZZLE BUT MINIMAL IMPACTS EXPECTED.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
MODEL FORECAST THERMAL PROFILES CONTINUE TO SUPPORT VERY LIGHT
FREEZING RAIN/DRIZZLE MAINLY ALONG AND NORTH OF A LINE FROM
MANNING TO AIKEN TO MCCORMICK DURING THE 12Z-15Z TIME FRAME
BEFORE SURFACE TEMPS BEGIN TO WARM ABOVE FREEZING FROM SOUTHEAST
TO NORTHWEST AS STRONG WARM ADVECTION AHEAD OF THE APPROACHING
SYSTEM ERODES THE WEDGE. CANNOT RULE OUT A TRACE OF ICE
ACCUMULATION ACROSS THE NORTHERN MIDLANDS AND AFTER COLLABORATION
WITH NEIGHBORING OFFICES DECIDED TO POST A FREEZING RAIN ADVISORY
FOR LANCASTER AND CHESTERFIELD COUNTIES ENDING AT 17Z. THINK
IMPACTS WILL BE MINIMAL WITH ANY ICING OCCURRING ON ELEVATED
SURFACES AND THERE IS A POSSIBILITY THAT LITTLE ACCUMULATION
OCCURS AT ALL GIVEN THE LACK OF DEEPER MOISTURE AVAILABLE.

CHANCES OF RAIN INCREASE THROUGH THE AFTERNOON INTO EVENING AS THE
UPPER TROUGH AMPLIFIES TO OUR WEST AND UPPER FORCING/ASCENT
INCREASE FROM WEST TO EAST. GENERALLY EXPECT A LULL IN PRECIP FROM
MID MORNING THROUGH LATE AFTERNOON AND THEN POPS RAMP UP TO
CATEGORICAL OVERNIGHT. POTENTIAL FOR PERIODS OF HEAVY RAIN AS
STRONG SOUTHERLY 50-55KT LOW LEVEL JET PROVIDES AMPLE MOISTURE
TRANSPORT INTO THE REGION. CANNOT RULE OUT AN ISOLATED ELEVATED
THUNDERSTORM AS LAPSE RATES BECOME STEEP AND CROSS TOTALS REMAIN
HIGH...ALTHOUGH SURFACE BASED INSTABILITY IS RELATIVELY
NON-EXISTENT. AVERAGE RAINFALL AMOUNTS COULD RANGE FROM A QUARTER
INCH TO AS MUCH AS 0.75 INCHES DUE TO INCREASED FORCING AS THE
UPPER TROUGH TAKES A NEGATIVE TILT.

NON STANDARD TEMPERATURE TREND EXPECTED WITH TEMPS RISING LATE
AFTERNOON AND OVERNIGHT MONDAY NIGHT DUE TO WARM ADVECTION AHEAD
OF THE SURFACE LOW. BREEZY CONDITIONS ALSO LIKELY AND A LAKE WIND
ADVISORY MAY BE NEEDED.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
A SHORTWAVE TROUGH EMBEDDED IN THE UPPER TROUGH OVER THE EASTERN
PART OF THE COUNTRY WILL EJECT EAST ACROSS THE FORECAST AREA TUESDAY
MORNING. THIS WILL DRIVE A COLD FRONT EAST THROUGH THE FORECAST AREA
EARLY TUESDAY. THE GFS MOVES THE MOISTURE OUT OF THE AREA MORE
QUICKLY THAN THE NAM AND IS WARMER WITH HIGH TEMPERATURES ON
TUESDAY. LEANED TOWARD THE GFS AND HAVE POPS GRADUALLY DECREASING
AFTER 12Z AND POPS LESS THAN 15 BY 18Z. THE MODELS CONTINUE TO SHOW
MUCH OF THE MOISTURE AND LIFT ASSOCIATED WITH ANOTHER MID-LEVEL
SHORTWAVE TROUGH REMAINING NORTH OF THE FORECAST AREA TUESDAY
NIGHT. WEAK HIGH PRESSURE WILL BUILD INTO THE SOUTHEASTERN US
BEHIND THE FRONT WITH A MUCH DRIER AIRMASS RETURNING THROUGH THE
END OF THE WORK WEEK. SURFACE LOW PRESSURE OVER SOUTHEASTERN
CANADA IS EXPECTED TO BRING THE NEXT FRONTAL BOUNDARY NEAR THE
AREA THIS WEEKEND. TEMPERATURES WILL GENERALLY BE NEAR TO ABOVE
NORMAL THROUGH THE LONG TERM PERIOD WITH HIGHS IN THE UPPER 50S TO
60S AND LOWS IN THE 30S AND 40S.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
MVFR CIGS DEVELOPING ACROSS THE TAF SITES THIS EVENING.

MOISTURE AND ISENTROPIC LIFT WILL INCREASE ACROSS THE AREA TONIGHT
AS WEDGE CONDITIONS DEVELOP. THERE IS A SLIGHT CHANCE OF RAIN AT
AGS/DNL/OGB AND FREEZING RAIN AT CAE/CUB BEGINNING JUST BEFORE
DAYBREAK MONDAY. THE CHANCE OF RAIN WILL INCREASE THROUGH THE
MORNING HOURS BUT AS TEMPERATURES RISE AT CAE/CUB...THE THREAT OF
ANY FROZEN PRECIP WILL DIMINISH. HAVE LEFT OUT MENTION OF PRECIP
DUE TO LOW CONFIDENCE IN TIMING AND MINIMAL IF ANY VISIBILITY
IMPACTS.

CIGS LOWERING TO MVFR IN THE 02Z-06Z TIME-FRAME. THE HRRR AND GFS
MODELS MORE PESSIMISTIC WITH CIGS LOWERING TO IFR 12Z-14Z. GIVEN
LOW CONFIDENCE WILL KEEP CIGS AT OR ABOVE 1000 FEET. WINDS WILL BE
EASTERLY 10 KNOTS OR LESS. NO FOG EXPECTED TO DEVELOP TONIGHT DUE
TO WIND AND CLOUDS. THE NAM MODEL DOES INDICATE THE POSSIBILITY OF
LLWS AFTER 06Z AS A 30 TO 40 KNOT LOW LEVEL JET MOVES INTO THE
AREA.

EXTENDED AVIATION OUTLOOK...WIDESPREAD CIG/VSBY RESTRICTIONS MONDAY
NIGHT INTO TUESDAY MORNING AS A SOUTHERN STREAM LOW PRESSURE SYSTEM
CROSSES THE REGION. STRONG GUSTY WINDS ALSO EXPECTED MONDAY NIGHT
INTO TUESDAY.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...FREEZING RAIN ADVISORY FROM 1 AM TO NOON EST MONDAY FOR SCZ015-
     016.

&&

$$


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