Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 010730
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
330 AM EDT SAT NOV  1 2014

.SYNOPSIS...
A STRONG UPPER LEVEL LOW WILL CONTINUE PUSHING TOWARDS THE REGION
OVERNIGHT...PUSHING A COLD FRONT THROUGH THE FORECAST AREA.
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/...
BASED ON LATEST OBSERVATIONS UPSTREAM GUSTY WINDS
EXPECTED ON AREA LAKES OVERNIGHT..ESPECIALLY CLARKS HILL. LAKE
WIND ADVISORY IN EFFECT AT 4AM.

AS OF 02Z...REGIONAL RADAR LOOP SHOWING MOST OF THE SHOWERS AND
THUNDERSTORMS ALONG AND AHEAD OF THE FRONT HAVE SHIFTED INTO THE
EASTERN HALF OF THE FORECAST AREA. HAVE RECEIVED REPORTS OF SOME
SMALL HAIL ASSOCIATED WITH THESE STORMS WHICH IS NOT SURPRISING
DUE TO THE RELATIVELY LOW FREEZING LEVEL AND WEAK INSTABILITY.
STORMS WILL TAPER OFF WITHIN THE NEXT COUPLE OF HOURS WITH MAINLY
RAIN SHOWERS THROUGH THE OVERNIGHT PERIOD.

THE DEEP UPPER LEVEL CUT OFF LOW WILL CONTINUE DIGGING TOWARD THE
CSRA OVERNIGHT. SURFACE ANALYSIS SHOWS THE COLD FRONT CURRENTLY
STRETCHED ACROSS THE UPSTATE OF SOUTH CAROLINA. THE FRONTAL
BOUNDARY WILL SHIFT EAST ACROSS THE FORECAST AREA TONIGHT. THE
HIGHEST RAIN CHANCES WILL BE IN THE NORTHERN MIDLANDS AND PEE DEE
REGIONS DURING THE OVERNIGHT PERIOD WHERE THE BEST MOISTURE IS
LOCATED. WINDS HAVE ALREADY PICKED UP ACROSS THE AREA TONIGHT AND
WILL CONTINUE TO INCREASE TOWARD SATURDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS AND COLD AIR ADVECTION INCREASES. OVERNIGHT
LOWS IN THE UPPER 30S WEST TO LOWER 40S EAST.

&&

.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. 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 SATURDAY. HAVE INTRODUCED RAIN MIXED WITH SNOW IN THE FAR
WESTERN MIDLANDS AND CSRA DURING THE 10Z TO 14Z TIME FRAME. BELIEVE
THIS AREA MAY HAVE THE BEST CHANCE TO SEE A MIX DUE TO THE COOLER
TEMPERATURES WRAPPING AROUND THE LOW IN THIS AREA AND THE BETTER
MOISTURE. 850 TEMPS ARE EXTREMELY IMPRESSIVE AT -5 TO -6 IN PARTS
OF THE CSRA. THE 18Z NAM HAS MOISTURE AND UPWARD VERTICAL MOTION
IN THE SNOW GROWTH REGION...WHILE THE GFS IS MORE MARGINAL. ALSO
CAN NOT RULE OUT SHALLOW CONVECTION WITH THE STRENGTH OF THE
LOW...WHICH COULD ALSO BRING SOME GRAUPEL 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 /07Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT CROSSING THE MIDLANDS THIS MORNING WAS EAST OF THE TAF
SITES. SCATTERED TO NUMEROUS RAIN SHOWERS WILL MOVE ACROSS THE TAF
SITES THIS MORNING AS AN UPPER LOW CURRENTLY OVER TN MOVES INTO THE
AREA. GIVEN COLD AIR ALOFT COULD SEE A FEW FLAKES OF SNOW MIX WITH
RAIN AT CAE/CUB DURING THE MORNING.

MVFR CONDITIONS SHOULD BE WIDESPREAD ACROSS THE MIDLANDS TODAY.
HIGH RESOLUTION MODEL AND SREF INDICATE A PERIOD OF IFR CIGS
10Z-18Z. AT THIS TIME CONFIDENCE TOO LOW TO INCLUDE IFR. VFR AT
AGS/DNL EXPECTED TO LOWER TO MVFR BY SUNRISE. NORTHWEST WINDS WILL
INCREASE THROUGH SUNRISE...BECOMING 15 KNOTS WITH GUSTS NEAR 30
KNOTS. AS THE LOW PRESSURE SYSTEM LIFTS OUT OF THE AREA WILL SEE VFR
CONDITIONS RETURN AFTER 21Z. STRONG AND GUSTY WINDS TO SUBSIDE AFTER
SUNSET.

.EXTENDED AVIATION OUTLOOK...
BREEZY CONDITIONS WILL SUBSIDE SUNDAY AFTERNOON. OTHERWISE...NO
SIGNIFICANT IMPACTS TO AVIATION EXPECTED THROUGH WEDNESDAY.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 4 AM EDT SATURDAY TO 10 AM EST SUNDAY
     FOR SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM 4 AM EDT SATURDAY TO 10 AM EST SUNDAY
     FOR GAZ040-063>065-077.
&&

$$





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