Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 280552
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1252 AM EST SAT FEB 28 2015

.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL BUILD INTO THE AREA OVER THE WEEKEND
WITH TEMPERATURES REMAINING BELOW NORMAL. A WARMING TREND IS
EXPECTED NEXT WEEK WITH SOUTHERLY FLOW DEVELOPING. A SERIES OF
FRONTS AFFECTING THE REGION WILL BRING PERIODS OF SHOWERS AND
POSSIBLY SOME THUNDERSTORMS.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HIGH PRESSURE WILL EXTEND FROM THE OHIO VALLEY TO MID-ATLANTIC
REGION TONIGHT. THE SYSTEM WILL DIRECT A NORTHEAST LOW-LEVEL FLOW
INTO THE FORECAST AREA. THE NAM AND GFS INDICATE ISENTROPIC LIFT
DEVELOPING TOWARD MORNING...BUT THE UPGLIDE SHOULD REMAIN WEAK
WITH SHALLOW MOISTURE. ALL OF THE GFS AND NAM MOS PLUS SREF
GUIDANCE INDICATE CONTINUED DRY CONDITIONS. WIND ASSOCIATED WITH
HIGH PRESSURE BUILDING NORTH OF THE REGION SHOULD HELP PREVENT FOG
TONIGHT DESPITE HIGH LOW-LEVEL MOISTURE FROM THE RECENT RAIN
EVENT. THE NAM AND GFS MOS PLUS SREF GUIDANCE WERE IN AGREEMENT
WITH LOW FOG PROBABILITIES. THE WARMER LOW TEMPERATURE GUIDANCE
MAY VERIFY BECAUSE OF WIND...BUT WE KEPT THE FORECAST CONSISTENT
AND LEANED TOWARD THE COOLER MAV MOS BECAUSE OF THE COLD AIR AND
SNOW COVER UPSTREAM.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SUNDAY/...
A LARGE 1044 MB SURFACE HIGH PRESSURE SYSTEM ACROSS THE OHIO RIVER
VALLEY TO THE EAST COAST WILL RIDGE DOWN THE EASTERN SEABOARD
SATURDAY INTO SATURDAY NIGHT. WEDGE CONDITIONS WILL DEVELOP LATE
SATURDAY WITH SOUTHWESTERLY FLOW ATOP THE SHALLOW NORTHEASTERLY
FLOW NEAR SURFACE. WEAK ISENTROPIC LIFT WILL OCCUR LATE SATURDAY
AFTERNOON AND SATURDAY NIGHT ACROSS THE REGION. THE NAM IS MOST
AGGRESSIVE AND BRINGS SOME LIGHT PRECIPITATION LATE SATURDAY
NIGHT. THE 12Z GFS IS BEGINNING TO LOOK MORE LIKE THE NAM. KEPT
DRY CONDITIONS FOR SATURDAY. INCREASING MOISTURE WILL RESULT IN
LOW CLOUDS ACROSS THE REGION. HAVE INDICATED A CHANCE FOR
PRECIPITATION DEVELOPING LATE SATURDAY NIGHT. IF SOME
PRECIPITATION DOES DEVELOP...THERE IS SOME POSSIBILITY OF LIGHT
FREEZING RAIN ACROSS THE NORTH MIDLANDS. CONFIDENCE REMAINS LOW SO
ONLY INDICATED A SLIGHT CHANCE FOR LIGHT FREEZING RAIN.

MOS GUIDANCE FOR HIGHS SATURDAY INDICATES UPPER 40S TO AROUND 50.
OUR FORECAST HIGHS REMAIN BELOW GUIDANCE DUE TO DEVELOPING WEDGE
CONDITIONS. OVERNIGHT LOWS SATURDAY NIGHT RANGING FROM NEAR 30
NORTH TO THE MID 30S SOUTH.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
THE EXTENDED FORECAST FEATURES A TRANSITION FROM THE PERSISTENT
COLD WEATHER TO A WARMING PATTERN WITH TEMPERATURES EXPECTED IN
THE 70S BY WEDNESDAY.

THE RELATIVELY FLAT UPPER PATTERN EARLY IN THE WEEK WILL ALLOW A
FAST MOVING SHORTWAVE TROUGH TO MOVE INTO NEW ENGLAND AND PUSH A
FRONT INTO THE FORECAST AREA SUNDAY NIGHT INTO MONDAY.
SIGNIFICANT UPPER HEIGHT FALLS ACROSS THE WESTERN STATES TUESDAY
WILL RESULT IN DOWNSTREAM RIDGING EAST OF THE MISSISSIPPI
RIVER...BRINGING QUITE THE WARM UP FOR OUR AREA. NEAR NORMAL
TEMPERATURES IN THE 60S EXPECTED MONDAY AND TUESDAY...THEN WELL
ABOVE NORMAL TEMPERATURES WEDNESDAY AS HIGHS SURGE INTO THE 70S.

THE WEATHER MAY REMAIN UNSETTLED THROUGH THE EXTENDED PERIOD AS
WAVES OF ENERGY MOVE THROUGH THE UPPER FLOW IMPACTING THE REGION
BUT THESE FAST MOVING DISTURBANCES ARE DIFFICULT TO TIME AND NOT
HANDLED WELL BY THE MODELS SO WHILE THERE WILL BE A CHANCE OF RAIN
IN THE FORECAST FOR MUCH OF THE PERIOD...IT WILL NOT BE RAINING
THE ENTIRE TIME.

A MORE SUBSTANTIAL STORM SYSTEM IS EXPECTED TO IMPACT MUCH OF THE
CENTRAL AND EASTERN PART OF THE COUNTRY WEDNESDAY INTO THURSDAY AS
THE UPPER TROUGH SHARPENS OVER THE MIDDLE OF THE COUNTRY WEDNESDAY...
DRIVING A COLD FRONT INTO THE REGION SOMETIME WEDNESDAY NIGHT
INTO THURSDAY. AHEAD OF THE FRONT...WARM AND MOIST SOUTHWESTERLY
FLOW IS EXPECTED WEDNESDAY CREATING BREEZY CONDITIONS AND MUCH
WARMER TEMPS THAN WE HAVE OBSERVED IN QUITE A WHILE. SOME
THUNDERSTORMS ARE EXPECTED TO ACCOMPANY THE FRONT BECAUSE OF THE
STRENGTH OF THE VIGOROUS UPPER TROUGH.

ONCE THE COLD FRONT CROSSES THE REGION...WE SHOULD SEE DRY AND
COOL CONDITIONS RETURN FOR FRIDAY.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...

HIGH PRESSURE CENTERED OVER THE MIDWEST IS RIDGING DOWN THE MID
ATLANTIC COAST. NE WINDS AND AN INFLUX OF DRIER LOW LEVEL AIR WILL
CONTINUE OVERNIGHT. MEANWHILE...SOME MID AND HIGH LEVEL CLOUDINESS
WILL STREAM EAST ACROSS THE REGION. COMBINATION OF WIND AND DRIER LOW
LEVEL AIR WILL PRECLUDE FOG DEVELOPMENT. ONLY EXCEPTION MAY BE IN
THE IMMEDIATE NEAR TERM AT FOG PRONE AGS WHERE DRIER AIR AND WIND
INCREASE HAS NOT REACHED THAT LOCATION YET. ISENTROPIC LIFT EXPECTED
TO COMMENCE LATE TODAY AND TONIGHT...WITH STRATOCU CLOUDINESS
DEVELOPING AND SPREADING NORTH INTO THE REGION...WITH BASES AT HIGH
END MVFR TO LOW END VFR EXPECTED. SOME LIGHT RAIN ALSO POSSIBLE.
PROVIDED VCSH MENTION AT AGS/DNL AFT 23Z.

EXTENDED AVIATION OUTLOOK...MVFR TO IFR CIG/VSBY RESTRICTIONS
EXPECTED LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH WEAK IN SITU
WEDGE OVER THE REGION. RESTRICTIONS AND A CHANCE OF PRECIPITATION
POSSIBLE AT TIMES MONDAY THROUGH THURSDAY AS A SERIES OF SYSTEMS
AFFECTS OUR REGION.

&&

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

$$






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