458
FXUS62 KCAE 162308
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
608 PM EST WED JAN 16 2019
SYNOPSIS
DRY HIGH PRESSURE WILL BE OVER THE AREA TONIGHT WITH LOWS IN THE
UPPER 20S TO LOW 30S. A LOW PRESSURE SYSTEM WILL CROSS THE
REGION THURSDAY NIGHT AND FRIDAY, FOLLOWED BY A MORE POWERFUL
STORM SYSTEM OVER THE WEEKEND AND MUCH COLDER TEMPERATURES EARLY
NEXT WEEK.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
HIGH PRESSURE OVER THE FORECAST AREA WILL LEAD TO LIGHT OR CALM
WINDS OVERNIGHT. MODELS HAVE BEEN SUGGESTING HIGH CLOUDS WILL
MOVE OVER THE FORECAST AREA EARLY THURSDAY MORNING INTERRUPTING
IDEAL RADIATIONAL COOLING CONDITIONS. ALTHOUGH RECENT RUNS HAVE
SHOWN A TREND IN DELAYING SIGNIFICANT CLOUD COVER UNTIL AFTER
SUNRISE. THEREFORE LOWS TONIGHT WILL DEPEND ON THE TIMING OF
THE HIGH CLOUDS MOVING OVER A WEAK UPPER RIDGE. THE TREND
TOWARDS THE LATER ARRIVAL OF THE CLOUDS SUPPORTS A LONGER
DURATION OF RADIATIONAL COOLING AND COOLER TEMPERATURES. IN
ADDITION THE ECMWF VERIFIED BETTER FOR YESTERDAY'S LOWS UNDER
SIMILAR CONDITIONS. THEREFORE WE EXPECT LOWS ON THE COOLER END
OF THE TEMPERATURE GUIDANCE SPECTRUM WITH LOWS FROM THE UPPER
20S TO LOW 30S. PATCHY FOG DEVELOPMENT IS EXPECTED, MAINLY ALONG
AREA RIVERS AND OTHER FOG PRONE SITES.
SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/
A FAST MOVING UPPER TROUGH WILL MOVE ACROSS THE OHIO VALLEY
THURSDAY AND INTO THE MID-ATLANTIC BY THURSDAY NIGHT. THE MAIN
UPPER LIFT ASSOCIATED WITH THE SHORTWAVE REMAINS WELL OFF TO THE
NORTH OF THE AREA, AND DEEPER MOISTURE REMAINS LIMITED WITH
THIS SYSTEM AS IT PUSHES EAST OF THE APPALACHIANS AND INTO THE
CWA. STILL ONLY EXPECTING MAINLY ISOLATED TO SCATTERED SHOWERS
WITH THIS FAST MOVING SYSTEM. RAINFALL TOTALS EXPECTED TO BE
LIGHT.
BEHIND THIS SYSTEM ON FRIDAY, SHORTWAVE RIDGING WILL BUILD OVER
THE FORECAST AREA, KEEPING THE AREA DRY FROM FRIDAY THROUGH
THE MAJORITY OF FRIDAY NIGHT. HIGHS ON THURSDAY WILL BE NEAR
NORMAL IN THE MID 50S TO LOWER 60S. FRIDAY SHOULD SEE WARMING
TEMPERATURES INTO THE 60S AS WARM ADVECTION TRIES TO RETURN.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
BY SATURDAY MORNING, A STRONGER SHORTWAVE WILL BE MOVING INTO
THE AREA FROM THE WEST. BOTH THE GFS AND ECMWF SHOWING BOTH
STRONG WARM ADVECTION AND MOISTURE ADVECTION INTO THE REGION.
SURFACE LOW DEVELOPS AND MOVES NORTHEASTWARD OUT OF THE LOWER
MS VALLEY DURING THE DAY SATURDAY, MOVING TOWARDS THE MID-ATLANTIC
BY SUNDAY MORNING. BEST CHANCE FOR RAINFALL ON SATURDAY SHOULD
BE ACROSS THE WESTERN CWA AND THE UPSTATE. RAINFALL SHOULD
OVERSPREAD THE ENTIRE CWA SATURDAY NIGHT INTO SUNDAY MORNING AS
THE BEST MOISTURE TRANSPORT AND UPPER DYNAMICS MOVE INTO THE
AREA. RAINFALL EXPECTED TO BE A LITTLE HEAVIER WITH THIS SYSTEM
DUE TO IT TAPPING INTO DEEPER MOISTURE PROFILES. THE WINDOW FOR
RAINFALL SHOULD BE ENDING BY LATE SUNDAY MORNING AS THE UPPER
TROUGH MOVES IN AND THE SURFACE FRONT PUSHES THROUGH.
BEHIND THE FRONT, WINDS WILL BE BREEZY ON SUNDAY AND MAY RESULT
IN THE NEED FOR A LAKE WIND ADVISORY.
COLD AND DRY ARCTIC HIGH PRESSURE SETTLES TOWARDS THE AREA
SUNDAY NIGHT INTO THE EARLY PORTIONS OF NEXT WEEK. COLD AIR
REMAINS INTO TUESDAY, WITH SOME MODERATION OF TEMPERATURES
BEGINNING BY WEDNESDAY.
AVIATION /00Z THURSDAY THROUGH MONDAY/
EXPECT MAINLY VFR CONDITIONS THROUGH THE 24-HOUR TAF PERIOD.
DRY HIGH PRESSURE RIDGING INTO THE FORECAST AREA WILL DOMINATE
TONIGHT. THE DRY AIR MASS SHOULD HELP PREVENT FOG EXCEPT
POSSIBLY AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. WE
CONTINUED TO FORECAST A PERIOD OF IFR FOG AT THESE TERMINALS.
THERE WILL BE INCREASED MOISTURE AHEAD OF A WEAK FRONT THURSDAY.
THE GFS AND NAM MOS SUPPORTED A VFR CEILING DEVELOPING DURING
THE AFTERNOON. THE MODELS DEPICT THE MORE SIGNIFICANT LIFT AND
MOISTURE STAYING NORTH OF THE TERMINALS. THE SHOWER CHANCE
TOWARD THE END OF THE PERIOD WAS TOO LOW TO INCLUDE IN THE
TERMINAL FORECASTS AT THIS TIME. WIND WILL BE LIGHT AND VARIABLE
ASSOCIATED WITH THE RIDGING THROUGH THE MORNING. THE NAM AND GFS
MOS SUPPORT SOUTH TO SOUTHWEST WIND 5 TO 10 KNOTS DEVELOPING
AHEAD OF THE FRONT DURING THE AFTERNOON.
EXTENDED AVIATION OUTLOOK...A WEAK FRONT LINGERING IN THE AREA
MAY BRING RESTRICTIONS DURING THE REST OF THURSDAY NIGHT AND
FRIDAY. A MORE POTENT STORM SYSTEM WILL CROSS THE AREA SATURDAY
AND SUNDAY WITH WIDESPREAD IFR ESPECIALLY SATURDAY NIGHT INTO
SUNDAY MORNING. BREEZY CONDITIONS MAY OCCUR SATURDAY NIGHT
THROUGH SUNDAY.
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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