Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 250829
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
429 AM EDT SAT APR 25 2015

.SYNOPSIS...
A WARM FRONT LIFTING NORTHWARD INTO THE AREA TODAY WILL BE THE FOCUS
FOR SHOWERS AND SOME THUNDERSTORMS TODAY. DRIER WEATHER RETURNS FOR
SUNDAY AS A COLD FRONT MOVES ACROSS THE REGION. THE NEXT CHANCE FOR
SIGNIFICANT RAIN MOVES IN FOR THE MIDDLE OF NEXT WEEK AS MOISTURE
INCREASES AHEAD OF A LOW PRESSURE SYSTEM COMING OUT OF THE GULF OF
MEXICO.

&&

.NEAR TERM /THROUGH TONIGHT/...
A WARM FRONT WILL LIFT NORTHWARD INTO THE AREA TODAY. PRECIPITABLE
WATER VALUES RAPIDLY INCREASE TO OVER ONE INCH BY SUNRISE...AND
NEAR 1.80 INCHES FOR THIS AFTERNOON. ISENTROPIC LIFT AND WARM
ADVECTION THIS MORNING WILL BRING WIDESPREAD SHOWERS TO THE AREA.
CATEGORICAL POPS LOOK IN ORDER FOR THIS MORNING. AS THE WARM FRONT
LIFTS NORTH THE AIRMASS WILL DESTABILIZE WITH INCREASING SPEED AND
DIRECTIONAL SHEAR...WHICH SUPPORT ROTATION STORMS. INSTABILITY
WILL BE LIMITED UNTIL LATE AFTERNOON AND TONIGHT WHEN LI VALUES
REACH MINUS 4C TO MINUS 5C AND CAPE AROUND 1500 J/KG.

POTENTIAL FOR SEVERE STORMS WITH TWO WAVES POSSIBLE. THE FIRST
IS ASSOCIATED WITH AN MCS COMPLEX PUSHING EASTWARD TO ARRIVE
AROUND MIDDAY INTO EARLY AFTERNOON...WITH FAVORABLE JET STREAM
DYNAMICS. ANOTHER ROUND EXPECTED TO ARRIVE THIS EVENING WHEN DRIER
AIR ALOFT REACHES THE AREA...COMBINED WITH THE BEST INSTABILITY.
SPC HAS OUR ENTIRE AREA IN A SLIGHT RISK WITH AN AREA OF ENHANCED
RISK ACROSS TN/KY.

TEMPERATURES TODAY WILL BE LIMITED BY THE CLOUDS AND RAINFALL FOR
MUCH OF THE DAY BUT THERE IS SOME UNCERTAINTY ABOUT SOME POSSIBLE
RECOVERY LATE. WE SHOULD SEE A GRADIENT IN TEMPS FROM THE 60S
NORTH TO 70S SOUTH.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
SOME LINGERING SHOWERS/STORMS POSSIBLE INTO SUNDAY WITH THE NORTHERN
MIDLANDS LIKELY TO BE MORE FAVORED ON SUNDAY AS THE SURFACE LOW
SINKS SOUTHEASTWARD ACROSS VA/NC AND OFFSHORE BY SUNDAY EVENING.
MODERATE TO STRONG INSTABILITY AND COLD 500MB TEMPS NOTED ON SUNDAY
BUT MOISTURE MAY BE LACKING TO SUPPORT MUCH CONVECTION SO WILL
CONTINUE WITH LOW CHANCE POPS ACROSS THE NORTHERN MIDLANDS.

SUNDAY LOOKS TO BE A WARM DAY WITH SOME SUNSHINE AND DOWNSLOPING
NORTHWESTERLY FLOW WITH HIGHS BACK INTO THE 80S. THE EXCEPTION
WILL BE THE EXTREME NORTHERN MIDLANDS WHERE COOLER BEHIND THE AREA
OF LOW PRESSURE SHOULD HOLD TEMPERATURES IN THE 70S.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
MEDIUM RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH THE OVERALL
PATTERN NEXT WEEK. ON MON/TUE THE FORECAST AREA WILL BE BETWEEN
THE DEPARTING SYSTEM OFF THE EAST COAST AND YET ANOTHER SLOW
MOVING CLOSED UPPER LOW EJECTING EASTWARD OUT OF THE SOUTHWESTERN
STATES. EXPECT DRY WEATHER AND BELOW NORMAL TEMPERATURES WITH A
PERSISTENT NORTHERLY FLOW AND SURFACE HIGH PRESSURE RIDGING INTO
THE AREA FROM THE NORTH. THE SOUTHERN STREAM CLOSED LOW WILL BEGIN
TO OPEN AND DRIFT EASTWARD EVENTUALLY PHASING WITH NORTHERN STREAM
ENERGY BRINGING UNSETTLED WEATHER TO OUR AREA TUESDAY INTO
THURSDAY. LATEST GFS SHOWS DRY HIGH PRESSURE BUILDING IN FROM THE
WEST FRIDAY. TEMPERATURES GENERALLY AT OR JUST BELOW NORMAL
THROUGH THE EXTENDED PERIOD.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH AROUND 12Z THEN LOWER
CONFIDENCE AS MVFR RESTRICTIONS EXPECTED TO DEVELOP ALL TERMINALS
AS WIDESPREAD RAIN OVERSPREADS THE REGION ASSOCIATED WITH WARM
ADVECTION AS A WARM FRONT LIFTS NORTHWARD. LIGHT RAIN EXPECTED TO
IMPACT THE TERMINALS AFTER 12Z WITH MVFR CIGS/VSBYS SETTING IN
BETWEEN 14Z-16Z. LIGHT SOUTH TO SOUTHEASTERLY WINDS SHOULD
DEVELOP BY 12Z AND GRADUALLY SHIFT TO THE SOUTH AND EVENTUALLY
SOUTHWEST AS A WARM FRONT LIFTS NORTH THROUGH THE REGION THOUGH
THE DAY. SOME CONVECTION WITH STRONG THUNDERSTORMS POSSIBLE AFTER
16Z THROUGH 03Z-06Z TONIGHT BUT TIMING AND LOCATION STILL
UNCERTAIN SO WILL ONLY MENTION RAIN FOR NOW. CIGS SHOULD BECOME
MORE BROKEN OR SCATTERED LATE AFTERNOON AS THE WARM FRONT LIFTS
NORTHWARD BUT TIMING REMAINS UNCERTAIN.

LOW-LEVEL WIND SHEAR MAY BE AN ISSUE BEFORE WARM FRONTAL PASSAGE.
HIGH SHEAR AND INSTABILITY NEAR THE WARM FRONT MAY HELP SUPPORT
SEVERE THUNDERSTORMS WITH DAMAGING WIND AND HAIL SATURDAY
AFTERNOON.

EXTENDED AVIATION OUTLOOK...SHOWERS AND THUNDERSTORMS WITH
ASSOCIATED RESTRICTIONS WILL BE POSSIBLE INTO SATURDAY EVENING.
BREEZY CONDITIONS POSSIBLE SUNDAY. NO SIGNIFICANT IMPACTS EXPECTED
MONDAY AND TUESDAY. AN APPROACHING WARM FRONT MAY RESULT IN
WIDESPREAD RESTRICTIONS WEDNESDAY.

&&

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

$$






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