Area Forecast Discussion
Issued by NWS Columbia, SC

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994
FXUS62 KCAE 042324
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
724 PM EDT WED MAY 4 2016

.SYNOPSIS...
COLD FRONT CONTINUES DEPARTING THE REGION ALLOWING A COOLER AND
DRIER AIRMASS TO OVERSPREAD THE AREA. A REINFORCING COLD FRONT
WILL CROSS THE AREA TONIGHT WITH MUCH COOLER TEMPERATURES ALONG
WITH A CHANCE OF SHOWERS FOR THURSDAY AND FRIDAY. DRY CONDITIONS
AND A WARMING TREND WILL DOMINATE THE AREA FOR THE WEEKEND INTO
EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
FAIR WEATHER IN THE NEAR TERM WITH DIURNAL CUMULUS EXPECTED TO
DISSIPATE EARLY THIS EVENING. BAND OF PRECIPITATION CURRENTLY TO
OUR NW ACROSS PORTIONS OF KY/TN ALONG AND AHEAD OF APPROACHING
UPPER LOW AND SURFACE BOUNDARY...SHIFTING TO THE SE. ARRAY OF
LATEST HIGH RESOLUTION MODELS AGREE IN INDICATING THE ACTIVITY
DISSIPATING AS IT APPROACHES AND MOVES INTO OUR NW FORECAST AREA
(FA)...BUT SLIGHT CHANCE POPS MAY BE IN ORDER ACROSS OUR NW FA
AROUND 03Z-05Z TONIGHT.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
CLOSED UPPER LOW WILL DROP SOUTH OVER THE CAROLINAS ON THURSDAY WITH
A SIGNIFICANT COLD POOL ALOFT WITH 500MB TEMPS AROUND -25C.  SURFACE
LOW PRESSURE OVER EASTERN NORTH CAROLINA WILL SHIFT OFFSHORE WHILE
PREDOMINANT SURFACE AND LOW LEVEL FLOW OVER THE FORECAST AREA WILL
BE FROM THE NORTHWEST.  0-3KM LAPSE RATES EXPECTED TO BECOME VERY
STEEP BY LATE MORNING THROUGH THE AFTERNOON AROUND 8-9 C/KM WITH
LIFTED INDEX VALUES FALLING TO AROUND -2C.  WHILE PRECIPITABLE WATER
VALUES WILL BE MARGINAL AROUND 0.5 TO 0.6 INCHES...IT SHOULD BE
SUFFICIENT ALONG WITH THE INSTABILITY TO PROVIDE DIURNAL CONVECTIVE
SHOWERS AND MAYBE ISOLATED THUNDERSTORMS.  CANNOT RULE OUT THE
POSSIBILITY OF A FEW SMALL HAIL OR GRAUPEL REPORTS DUE TO THE
SIGNIFICANT COLD POOL ALOFT AND STRONGER WIND GUSTS WITH EVAPORATIVE
COOLING THAT WILL TAKE PLACE WITH DRY AIR ALOFT AND A BIT OF AN
INVERTED-V SOUNDING NEAR THE SURFACE. HAVE INCREASED THE POPS A
BIT ACROSS THE NORTHERN MIDLANDS TO SOLID CHANCE POPS AND TAKE THE
SLIGHT CHANCE POPS INTO THE CSRA.

SHOWERS SHOULD WANE DURING THE EVENING HOURS AS THE ATMOSPHERE
RESTABILIZES WITH THE LOSS OF HEATING BUT COULD SEE SOME LINGERING
SHOWERS ACROSS THE NORTHERN MIDLANDS CLOSER TO THE CENTER OF THE
UPPER LOW AND BETTER FORCING.  THE UPPER LOW WILL LIFT INTO EASTERN
NC/VA THURSDAY NIGHT AND BECOME NEARLY STATIONARY AS MORE SHORTWAVE
ENERGY DIVES DOWN THE BACK SIDE OF THE UPPER LOW FOR FRIDAY WHICH
WILL WARRANT KEEPING SOME POPS ACROSS THE PEE DEE REGION AND
MIDLANDS NORTH OF A LINE FROM NEWBERRY TO COLUMBIA TO LAKE MARION.
THE UPPER LOW WILL PULL AWAY FROM THE REGION FRIDAY NIGHT AS SKIES
CLEAR WITH NO PRECIPITATION EXPECTED.

TEMPERATURES WILL BE WELL BELOW NORMAL THIS PERIOD WITH HIGHS
STRUGGLING TO GET INTO THE 70S ON THURSDAY DUE TO CLOUD COVER AND
COOL AIR MASS AND SHOWERS ASSOCIATED WITH THE UPPER LOW.  SLIGHTLY
WARMER TEMPERATURES EXPECTED ON FRIDAY WITH HIGHS IN THE LOWER TO
MID 70S.  LOWS THURSDAY NIGHT WILL BE IN THE UPPER 40S AND FURTHER
COOLING LIMITED BY A MIXED BOUNDARY LAYER FOLLOWED BY SLIGHTLY
WARMER TEMPERATURES FRIDAY NIGHT IN THE LOWER 50S.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
NOT TOO MUCH CHANGE IN THE FORECAST THIS PERIOD FROM PREVIOUS
FORECAST AS PATTERN TRANSITIONS A BIT WITH THE CLOSED UPPER LOW
OPENING UP AND LIFTING AWAY FROM THE MID-ATLANTIC AS ANOTHER
SHORTWAVE MOVES ACROSS THE NORTHEAST AND UPPER FLOW BECOMES MORE
ZONAL OVER THE FORECAST AREA.

NORTHWEST TO WESTERLY DOWNSLOPING MID LEVEL FLOW TRANSITIONS TO MORE
WESTERLY FLOW AND A DEVELOPING SOUTHERLY SURFACE FLOW WILL ALLOW FOR
MODERATING TEMPERATURES OVER THE WEEKEND WITH TEMPS RISING BACK
ABOVE NORMAL IN THE UPPER 80S TO AROUND 90 EARLY NEXT WEEK. SOME
GENERAL AGREEMENT AMONG THE MEDIUM RANGE MODELS SHOW UPPER RIDGING
OVER THE SOUTHEASTERN STATES WHILE A DEEP CLOSED LOW SLOWLY DRIFTS
EASTWARD OUT OF THE INTERMOUNTAIN WEST.  THIS WILL SET UP A SERIES
OF SHORTWAVES MOVING THROUGH THE SOUTHWESTERLY FLOW TO TRACK OUT OF
THE MISSISSIPPI VALLEY NORTHEASTWARD TOWARDS THE FORECAST AREA MID
WEEK. THERE REMAINS SOME DIFFERENCES AMONG THE MODELS REGARDING
MOISTURE AVAILABLE AND HOW THAT MAY RESULT IN PRECIPITATION FOR OUR
AREA SO WILL CONTINUE A DRY FORECAST THROUGH TUESDAY AND INTRODUCE
SLIGHT CHANCE POPS ON WEDNESDAY.

TEMPERATURES THROUGH THIS PERIOD WILL BE SLIGHTLY BELOW TO NEAR
NORMAL ON SATURDAY WITH HIGHS IN THE LOWER 80S BUT THEN WARM ABOVE
NORMAL SUNDAY THROUGH WEDNESDAY WITH HIGHS IN THE UPPER 80S TO
AROUND 90 DEGREES.  LOWS WILL GENERALLY BE IN THE 60S.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS THROUGH THE PERIOD.

A COLD FRONT WILL MOVE ACROSS THE REGION OVERNIGHT...AROUND 09Z.
MID LEVEL CLOUDS EXPECTED WITH THE FRONT. VERY LIGHT RAIN POSSIBLE
MAINLY AT THE CAE/CUB TERMINALS BUT NOT EXPECTED TO RESULT IN
RESTRICTIONS. DEEP UPPER LEVEL LOW OVER THE REGION THURSDAY.
BROKEN STRATO-CUMULUS DECK EXPECTED AT TIMES ALTHOUGH VFR. A FEW
SHOWERS POSSIBLE AT BUT CONFIDENCE NOT HIGH ENOUGH TO INCLUDE IN
TERMINALS. WINDS WEST-NORTHWEST THURSDAY AND POSSIBLY GUSTY TO
AROUND 20 KNOTS.

EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.

&&

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

&&

$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99



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