Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 282102
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
500 PM EDT SAT MAR 28 2015

.SYNOPSIS...
A COLD AIR MASS OVER THE NORTHERN AND CENTRAL PLAINS WILL MOVE
SOUTHEAST AND SETTLE OVER THE REGION SUNDAY...THEN SHIFT OFF THE
COAST SUNDAY NIGHT. NEAR OR BELOW FREEZING TEMPERATURES EXPECTED LATE
TONIGHT AND EARLY SUNDAY MORNING...AS THE CENTER OF A COLD AIR
MASS SETTLES IN OVERHEAD. A FRONT IS EXPECTED TO MOVE THROUGH
EARLY MONDAY AFTERNOON PROVIDING A CHANCE OF SHOWERS. SOME
MOISTURE RETURN EXPECTED MID TO LATE NEXT WEEK AND WARMING
TEMPERATURES.

&&

.NEAR TERM /THROUGH TONIGHT/...
LONGWAVE UPPER TROUGH OVER THE EASTERN STATES. WEAK SURFACE
TROUGH ACROSS THE AREA. A FEW SCATTERED CLOUDS THROUGH THE
AFTERNOON WITH COLD ADVECTION. DESPITE COLD ADVECTION WITH
DOWNSLOPE FLOW EXPECT TEMPERATURES TO RISE INTO THE LOWER TO
MIDDLE 50S MOST AREAS.

UPPER LEVEL LONGWAVE TROUGH WILL SHIFT OFF THE COAST TONIGHT.
SURFACE RIDGE TO THE NORTHWEST WILL BE BUILDING ACROSS THE REGION
OVERNIGHT. CLOUDINESS ACROSS THE LOWER MISSISSIPPI VALLEY AND GULF
COAST AREA ASSOCIATED WITH UPPER LEVEL JET STREAK WILL REMAIN
SOUTH AND WEST OF THE AREA OVERNIGHT. MODELS INDICATE AIR MASS
QUITE DRY. WEAK SURFACE BASED INVERSION OVERNIGHT AND LOW- LEVEL
JET NEAR 25 KTS THROUGH ABOUT MIDNIGHT...THEN WEAKENS TOWARD
MORNING. SO STRONG RADIATIONAL COOLING CONDITIONS EXPECTED. MOS
CONSENSUS GUIDANCE HAS BEEN CONSISTENT WITH FREEZING TEMPERATURES
ACROSS THE REGION FOR SEVERAL RUNS. LOCAL RADIATION SCHEME IS IN
AGREEMENT WITH FREEZING CONDITIONS. HIGHEST PROBABILITY FOR HARD
FREEZE REMAINS ACROSS THE PIEDMONT WHERE RIDGE AXIS WILL BE
LOCATED AND ACROSS THE NORTHERN MIDLANDS AND PEE DEE. FREEZE
WARNING IN EFFECT LATE TONIGHT THROUGH EARLY SUNDAY MORNING.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
TEMPERATURES SHOULD CLIMB BACK UP ABOVE FREEZING ACROSS THE AREA
BY 14Z...THEN WITH PLENTY OF SUNSHINE AFTERNOON WITH SHORT WAVE
RIDGE ALOFT. READINGS WILL RISE INTO THE 50S...WHICH IS STILL ABOUT 15
DEGREES BELOW NORMAL. AN UPPER LEVEL TROUGH IN THE NORTHERN PLAINS
EARLY IN THE DAY WILL TRACK EAST AND DE-AMPLIFY...HOWEVER TROUGH
WILL DRIVE A WEAK COLD FRONT/TROUGH TOWARD THE REGION SUNDAY
NIGHT. THE AIR MASS WILL BEGIN TO MODIFY AS WINDS TURN MORE
SOUTH/SOUTHWEST ON THE BACKSIDE OF THE HIGH...ALLOWING WARM/MOIST
ADVECTION TO DEVELOP AHEAD OF THE FRONT SUNDAY NIGHT. MODERATING
OVERNIGHT TEMPERATURES EXPECTED. LOW LEVEL MOISTURE
ADVECTION/ISENTROPIC LIFT INCREASES BRIEFLY MONDAY MORNING AIDED
BY 35-50 KTS 850MB JETMAX AND STRONG SPEED CONVERGENCE NOTED
ACROSS THE MIDLANDS. IN ADDITION MID LEVEL SHORT WAVE ROTATING
THRU UPPER TROUGH WILL PROVIDE ADDITIONAL LIFT. PRECIPITABLE WATER
SHOULD BE SOMEWHAT LIMITED WITH WEST LOW LEVEL FLOW AND QPF MOSTLY
LIGHT. MOS SUPPORTS CHANCE POPS WITH HIGHEST PROBABILITY RAIN IN
THE NORTHERN MIDLANDS WHERE UPPER LEVEL DYNAMICS A LITTLE
STRONGER. MODEL SOUNDINGS SUGGEST INSTABILITY WEAK...ALTHOUGH
THUNDER POSSIBLE/MAINLY CSRA...NOTED SHOWALTER INDEX AROUND -1.
HOWEVER SREF CAPE PROBABILITY LOW. CLEARING EXPECTED DURING THE
AFTERNOON AS FRONT...LIKELY UNDERGOING FRONTOLYSIS MOVES SOUTHEAST
OF AREA. WITH WARM ADVECTION TEMPERATURES IN THE 60S...POSSIBLY
WARMER CSRA BUT STILL BELOW NORMAL.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODEL TIMING DIFFERENCES NOTED LATE IN THE PERIOD...
DRY CONDITIONS BACK FOR MONDAY NIGHT AND FOR MUCH OF WEDNESDAY.
ANOTHER SYSTEM WILL MOVE TOWARDS THE AREA LATE WEDNESDAY NIGHT
INTO THURSDAY...WHICH WILL BRING YET ANOTHER RAINFALL CHANCE TO
THE AREA. A COLD FRONT MOVES TOWARD THE REGION FRIDAY OR SATURDAY...HOWEVER
MODEL TIMING DIFFERENCES NOTED AND CONFIDENCE REMAINS LOW ON
DETAILS. WILL CONTINUE WITH LOW CHANCE TO CHANCE POPS THROUGH THE
END OF THE PERIOD. WARMING TREND THROUGH THE PERIOD...WITH
TEMPERATURES POSSIBLY ABOVE NORMAL LATE IN THE PERIOD.

&&

.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
HIGH CONFIDENCE FOR VFR CONDITIONS THROUGH THE 24 HOUR TAF PERIOD AS
HIGH PRESSURE BUILDS INTO THE AREA. SCATTERED CLOUDS WITH BASES NEAR
7000 FEET EXPECTED TO DISSIPATE WITH SUNSET. W TO NW WINDS
AROUND 12 KNOTS WITH GUST UP TO 20 KNOTS WILL DIMINISH AROUND
SUNSET. WINDS BECOMING LIGHT AND VARIABLE OR CALM BY LATE TONIGHT
INTO SUNDAY MORNING AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD.

EXTENDED AVIATION OUTLOOK...A BRIEF PERIOD OF SHOWERS AND ASSOCIATED
RESTRICTIONS MONDAY AS A FAST MOVING COLD FRONT CROSSES THE REGION.
NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED TUE. INCREASING MOISTURE
AND RESTRICTIONS EXPECTED LATE WED INTO THU.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FREEZE WARNING FROM 2 AM TO 10 AM EDT SUNDAY FOR SCZ015-016-
     018-020>022-025>031-035>038-041.
GA...FREEZE WARNING FROM 2 AM TO 10 AM EDT SUNDAY FOR GAZ040-
     063>065-077.
&&

$$





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