Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 010011
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
811 PM EDT FRI OCT 31 2014

.SYNOPSIS...
A STRONG UPPER LEVEL LOW WILL MOVE TOWARDS THE REGION THIS
EVENING...HELPING TO PUSH A COLD FRONT THROUGH THE FORECAST AREA
TONIGHT. BEHIND THIS FRONT...MUCH COLDER AIR WILL FOLLOW ALONG
WITH BREEZY CONDITIONS. THE FIRST WIDESPREAD FROST ALONG WITH THE
FIRST FREEZE OF THE SEASON FOR SOME AREAS WILL LIKELY OCCUR SUNDAY
NIGHT/MONDAY MORNING.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
REGIONAL RADAR LOOP EARLY THIS EVENING SHOWS LIGHT ISOLATED
SHOWERS MOVING EAST ACROSS THE AREA. MODELS REMAIN IN GOOD
AGREEMENT WITH THE EVOLUTION OF THE COMPLEX WEATHER PATTERN ACROSS
THE EASTERN U.S. THE DEEP UPPER LEVEL TROUGH WILL CONTINUE ACROSS
THE REGION...WITH A STRONG SHORTWAVE MOVING AROUND THE BASE OF THE
TROUGH HELPING TO CUTOFF THE LOW OVERNIGHT AS IT MOVES THROUGH TN
AND NRN GA. GIVEN THE STRONG DYNAMICS OF THIS SYSTEM...WITH A
STRONG COLD POOL ALOFT MOVING TOWARDS THE REGION...THE MODELS
CONTINUE THE TREND OF BRINGING SHOWERS INTO THE WESTERN AND
NORTHERN MIDLANDS TONIGHT...WITH THE HIGHEST RAIN CHANCES NORTH.
THE LEADING EDGE OF THE FRONT ASSOCIATED WITH THIS SYSTEM SHOULD
PUSH THROUGH TONIGHT...WITH WINDS INCREASING LATE TONIGHT AND
TOWARDS MORNING. ALTHOUGH THERE WILL BE A NOTICEABLE COOLDOWN
BEHIND THE LEADING EDGE...THE MAIN COLD SURGE WILL NOT MOVE IN
UNTIL TOMORROW. OVERNIGHT LOWS RIGHT NOW FORECAST GENERALLY AROUND
40.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
THE CLOSED OFF UPPER LOW WILL CONTINUE TO MOVE EAST INTO THE
UPPER SAVANNAH RIVER VALLEY BY SATURDAY MORNING...THEN RAPIDLY
MOVE TOWARDS THE COAST BY EARLY SATURDAY AFTERNOON.

HAVE GONE WITH LIKELY POPS ON SATURDAY ACROSS THE NORTHERN
MIDLANDS WITH A GRADUAL TAPER IN POPS SOUTHWARD THROUGH THE
PERIOD. THE LOCAL TOP-DOWN PRECIP TOOL KEEPS THE CWA IN ALL RAIN
THROUGH THE DAY. SIGNIFICANT COLD POOL ALOFT WITH THIS
SYSTEM...AND THUS WITH SUCH COLD TEMPERATURES ALOFT...WOULD NOT
BE SURPRISED TO SEE A FEW REPORTS OF FROZEN PRECIPITATION MIXED IN
WITH THE LIGHT RAIN EARLY/MIDDAY SATURDAY. ALSO CAN NOT RULE OUT
SHALLOW CONVECTION WITH THE STRENGTH OF THE LOW...WHICH COULD ALSO
BRING SOME GRAUPLE TO THE AREA.  NO ACCUMS...AND CONFIDENCE NOT
HIGH. EXPECT RAIN TO BE THE MAIN PRECIPITATION TYPE THROUGH THE
EVENT.

TEMPERATURES ON SATURDAY WILL BE SIGNIFICANTLY COLDER...NEARLY
15-20 DEGREES COLDER THAN RECENT DAYS...WITH HIGHS STRUGGLING TO
REACH 50 DEGREES IN THE MIDLANDS. MAX TEMPERATURES WILL RANGE FROM
THE MID TO UPPER 40S ACROSS MUCH OF THE NORTHERN MIDLANDS...THE
POSSIBLY THE LOWER 50S IN THE CSRA. THE OTHER FORECAST ISSUE TO
DEAL WITH DURING THIS PERIOD WILL BE THE INCREASING SURFACE
GRADIENT AND THE STRONG 40 TO 50 KNOT LOW LEVEL JET MOVING ACROSS
THE REGION SATURDAY AFTERNOON AND EVENING. THE STRONGEST WINDS
WILL DEVELOP ACROSS THE CWA ON SATURDAY AND CONTINUE SATURDAY
EVENING WITH A GRADUAL DECREASE TOWARD SUNDAY MORNING. WITH THE
LAKE WATER TEMPERATURES IN THE UPPER 60S TO AROUND 70 DEGREES AND
STRONG COLD AIR ADVECTION...EXPECT WINDS TO REMAIN RATHER BREEZY
ACROSS THE LAKES FROM SATURDAY MORNING TO SUNDAY MORNING. WILL
CONTINUE WITH THE CURRENT LAKE WIND ADVISORY WHICH RUNS FROM 10 AM
EDT SATURDAY UNTIL 10 AM EST SUNDAY. SUSTAINED WINDS 15 TO 25 MPH
WITH GUSTS AS HIGH AS 30 TO 40 MPH EXPECTED ON SATURDAY/SATURDAY
EVENING.

AS THE UPPER LOW MOVES OFFSHORE BY SATURDAY EVENING...HIGH PRESSURE
ASSOCIATED WITH A COLD DRY CANADIAN AIRMASS WILL SETTLE OVER THE
AREA FOR THE REMAINDER OF THE WEEKEND. A STRONG PRESSURE GRADIENT
WILL PERSIST THROUGH THE OVERNIGHT HOURS SATURDAY NIGHT WHICH WILL
PREVENT IDEAL STRONG RADIATIONAL COOLING FROM OCCURRING BY
KEEPING MUCH OF THE BOUNDARY LAYER WELL MIXED. THIS MEANS THAT
LOWS SATURDAY NIGHT AND SUNDAY MORNING WILL GENERALLY BE DETERMINED
BY THE COLD ADVECTION TAKING PLACE INSTEAD OF BY RADIATIONAL
COOLING. THIS PUTS LOWS GENERALLY IN THE MID 30S.

SUNDAY WILL FEATURE DECREASING CLOUDINESS AND MOSTLY SUNNY SKIES
WITH SLIGHTLY WARMER BUT STILL WELL BELOW NORMAL TEMPERATURES WITH
HIGHS IN THE 50S. THE BEST NIGHT FOR WIDESPREAD FROST AND THE
POTENTIAL FOR FREEZING TEMPERATURES APPEARS TO BE LATE SUNDAY
NIGHT AND MONDAY MORNING. WINDS SHOULD DIMINISH UNDER LOW-LEVEL
INVERSION...SKIES WILL BE CLEAR...AND AIRMASS WILL BE DRY. THIS
CREATES IDEAL RADIATIONAL COOLING CONDITIONS. OVERNIGHT LOWS WILL
FALL INTO THE LOWER TO MID 30S...WITH UPPER 20S REMAINING POSSIBLE
IN THE TYPICAL COLD SPOTS. SOME OF THE NUMBERS FOR BUSH FIELD
STILL TRY TO TAKE THE TEMPERATURE DOWN INTO THE MID/UPPER
20S...WHICH IS QUITE IMPRESSIVE AND SEASONABLY COLD FOR EARLY
NOVEMBER.

FOR SUNDAY NIGHT...AT A MINIMUM WILL LIKELY NEED A FROST
ADVISORY...BUT IF GUIDANCE CONTINUES THE DOWNWARD TREND...AND IT
CONTINUES TO SHOW IDEAL RADIATIONAL CONDITIONS...A FREEZE WARNING
MAN BE NEEDED INSTEAD FOR PORTIONS OF THE CWA. THESE WOULD BE
ISSUED WITH LATER PACKAGES IF NEEDED.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
BEHIND THIS SYSTEM...COOL AND DRY WEATHER SHOULD PERSIST AT LEAST
INTO WEDNESDAY. MONDAY MORNING TEMPERATURES WILL START OFF WELL
BELOW NORMAL IN THE LOWER TO MID 30S...WITH WIDESPREAD FROST
EXPECTED ALONG WITH SOME AREAS OF FREEZING/BELOW FREEZING
TEMPERATURES. FULL SUNSHINE EXPECTED WITH A DRY AIRMASS IN PLACE
WILL YIELD SLIGHTLY WARMER TEMPERATURES COMPARED TO SUNDAY BUT
STILL REMAINING WELL BELOW NORMAL. THE SURFACE RIDGE WILL SHIFT
OFFSHORE ON TUESDAY WITH A RETURN SOUTHERLY FLOW EXPECTED AROUND
THE SURFACE HIGH...WHICH WILL PROVIDE WARMER TEMPERATURES AND
INCREASED LOW LEVEL MOISTURE. NEAR NORMAL TEMPERATURES EXPECTED
TUESDAY WITH HIGHS IN THE UPPER 60S TO LOWER 70S AND MUCH WARMER
MIN TEMPERATURES TUESDAY NIGHT IN THE UPPER 40S.

THE FORECAST BECOMES A BIT MORE CHALLENGING AND LESS CONFIDENT BY
MID WEEK...DUE TO TIMING AND STRENGTH ISSUES. WILL CARRY SLIGHT
CHANCE POPS WED NGT/THU WITH APPROACHING FRONT. TEMPERATURES WILL
WARM BACK TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT. SCATTERED SHOWERS
HAVE FORMED AHEAD OF THE COLD FRONT AND WILL BE IN THE VICINITY OF
ORANGEBURG FOR THE NEXT FEW HOURS. NORTHWESTERLY WINDS WILL BEGIN TO
STRENGTHEN AS THE FRONT PASSES BRINGING LOWERED CEILINGS AND THE
POSSIBILITY OF SHOWERS AFTER 09Z. ON SATURDAY... THE BEST CHANCE FOR
WIDESPREAD SHOWERS REMAINS IN THE PEE DEE AND NORTHERN MIDLANDS.
CONFIDENCE HAS INCREASED TO ADD -SHRA AFTER 15Z FOR THE COLUMBIA
AIRPORTS.

NORTHWEST SURFACE WINDS NEAR 15 KNOTS WITH GUSTS UP TO 30 KNOTS ARE
LIKELY THROUGHOUT THE DAY WITH THE STRONGEST WINDS EXPECTED IN THE
LATE AFTERNOON.

.EXTENDED AVIATION OUTLOOK...
BREEZY CONDITIONS EXPECTED TO CONTINUE INTO SUNDAY MORNING WHICH
WILL INHIBIT FOG AND FROST FORMATION FOR SUNDAY MORNING. DRY AIR
BEHIND THE FRONT WILL ALLOW FOR CLEAR SKIES INTO MONDAY. THERE IS A
POSSIBILITY FOR FROST MONDAY MORNING AS TEMPERATURES DROP NEAR
FREEZING WITH LIGHT WINDS.

&&

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

$$






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