798
FXUS62 KGSP 232353
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
653 PM EST SAT FEB 23 2019
SYNOPSIS
THE WET PATTERN WILL CONTINUE THROUGH TONIGHT BEFORE A ROBUST
COLD FRONT FINALLY MOVES THROUGH THE REGION LATE TONIGHT THROUGH
SUNDAY MORNING. THE EARLY PART OF THE WEEK SHOULD BE DOMINATED
BY DRY HIGH PRESSURE. A COLD FRONT MAY MOVE THROUGH THE REGION FROM
THE NORTHWEST ON WEDNESDAY, BUT MOISTURE WITH THIS FRONT REMAINS
HIGHLY UNCERTAIN. BETTER MOISTURE COULD ARRIVE TOWARD NEXT WEEKEND.
NEAR TERM /THROUGH SUNDAY/
630 PM UPDATE...ADJUSTED BROAD AREAS OF COOLER THAN FCST/D TEMPS AND
TD/S. WEDGE IS HOLDING STRONG AND GOOD MOISTURE ADV WILL KEEP LOW
CLOUDS AND OCCASIONAL LOWER VSBY OVER THE FA THIS EVENING. PRECIP
HAS DROPPED OFF AND LOWERED POPS A BIT UNTIL UPSLOPE ENHANCED
PRE/FRONTAL -SHRA BEGINS ACROSS THE WRN NC MTNS LATER THIS EVENING.
AS OF 250 PM: WITH NOT MUCH OF A CHANGE FROM YESTERDAY, IT'S BEEN
QUITE THE DREARY LAST SATURDAY OF FEBRUARY, WITH EXPANSIVE CLOUD
COVER, ISOLATED TO SCATTERED SHOWERS/DRIZZLE, AND BELOW NORMAL
TEMPERATURES. THIS ALL A RESULT OF THE CAD SET UP IN PLACE ACROSS
THE CAROLINAS (AND UPGLIDE OVER THIS FEATURE), WITH SFC HIGH
PRESSURE OFF TO THE NORTHEAST, AND UPPER RIDGING IN PLACE. THOUGH
LATEST RADAR IMAGERY CONTINUES TO DEPICT A LULL IN PRECIPITATION
ACROSS THE FA THIS AFTERNOON, WITH THE HEAVIER RAINFALL CURRENTLY
ACROSS MUCH OF TN INTO VA, DO EXPECT RAINFALL COVERAGE TO PICK UP
TONIGHT AS A STRONG COLD FRONT PUSHES THROUGH THE AREA OVERNIGHT
INTO SUNDAY MORNING, WITH IT'S PARENT SFC LOW EJECTING FROM THE
CENTRAL PLAINS INTO THE UPPER MIDWEST. WITH ANOTHER ROUND OF HEAVY
RAINFALL (THOUGH QPF AMOUNTS REMAIN AT OR BELOW 0.50"), ALREADY
SATURATED SOILS FROM THE PAST FEW DAYS, AND AREA RIVERS AND STREAMS
ALREADY NEARING THEIR BANKS, WITH SOME ALREADY IN MINOR FLOOD STAGE,
A FLOOD WATCH REMAINS IN EFFECT FOR PORTIONS OF THE FA THROUGH INTO
SUNDAY. WITH THE WEDGE SLOW TO RETREAT, EXPECT OVERNIGHT LOW
TEMPERATURES IN THE MID TO UPPER 40S ACROSS THE SOUTHERN MOUNTAINS,
NORTHEAST GA, AND MOST OF THE UPSTATE, COOLER INTO THE LOWER 40S
ACROSS THE NW PIEDMONT.
BEHIND THE COLD FRONT, CONDITIONS WILL DRY QUICKLY WITH THE RETURN
OF NW FLOW, WITH CLEARING SKIES INTO LATE MORNING/EARLY AFTERNOON ON
SUNDAY. WITH THE PROJECTED TIGHTENING PRESSURE GRADIENT PER LATEST
GUIDANCE, A WIND ADVISORY AS WELL AS A HIGH WIND WARNING ARE IN
EFFECT FOR PORTIONS OF WESTERN NC, WITH A WIND ADVISORY BEGINNING AS
EARLY AS TONIGHT FOR THE HIGHER ELEVATIONS AHEAD OF THE APPROACHING
COLD FRONT, EXPANDING TO ALL ACROSS ACROSS THE NC MOUNTAINS ON
SUNDAY. PLEASE SEE CURRENT PRODUCTS FOR ADDITIONAL INFORMATION.
ELSEWHERE, ACROSS THE UPSTATE AND NW PIEDMONT, EXPECT GUSTY WINDS
THROUGHOUT THE DAY. THOUGH WINDS ARE EXPECTED TO REMAIN BELOW
ADVISORY CRITERIA, WITH SATURATED SOILS, WOULD NOT ENTIRELY RULE OUT
THE POTENTIAL FOR A FEW WEAK DOWNED TREES. HIGH TEMPERATURES ON
SUNDAY WILL REBOUND TO ABOVE NORMAL.
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
AS OF 1248 PM EST SATURDAY: AFTER THE WEEK WE'VE HAD, THE FIRST
PART OF NEXT WEEK WILL BE A WELCOME BREAK. THE ONLY ISSUE WILL BE
THE WIND, WHICH STILL LOOKS VERY STRONG ACROSS THE RIDGETOPS AND
PEAKS OF THE NORTHERN MOUNTAINS OF NC, BUT PROBABLY NOT A PROBLEM
OUTSIDE THE MTNS. FCST SOUNDINGS SHOW THE BOUNDARY LAYER DECOUPLING
SUNDAY EVENING ACROSS THE FOOTHILLS, SO WE LOSE THE DEEPER MIXING
THAT WOULD ALLOW THE STRONGER WINDS TO REACH THE GROUND. BY THE
TIME WE WARM UP ON MONDAY MORNING, THE STRONG WINDS WILL BE PULLING
OUT TO THE NORTH. THE REST OF THE FORECAST WILL BE FAIR AND DRY,
COURTESY OF A NEARLY-ZONAL UPPER PATTERN THAT SUPPORTS HIGH PRESSURE
RIDGING DOWN FROM THE NW ON MONDAY AND THEN MOVING BY TO THE NORTH
ON TUESDAY. TEMPS SHOULD BE ABOUT A CATEGORY ABOVE NORMAL WITH A
SLIGHT WARMING TREND FROM MONDAY INTO TUESDAY.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
AS OF 204 PM EST SATURDAY: STILL NOT A LOT OF CONFIDENCE IN THE
FORECAST FOR THE LATTER HALF OF THE WEEK, AS THERE ISN'T MUCH OF A
COHERENT SIGNAL IN THE MODEL GUIDANCE AND CONSISTENCY/CONSENSUS
ARE FAIRLY POOR, ALTHO IT ACTUALLY IMPROVES AS WE HEAD INTO
NEXT WEEKEND. THE UPPER FLOW PATTERN STAYS RELATIVELY FLAT FOR
WEDNESDAY AND THURSDAY, THEN STARTS TO BUCKLE INTO FRIDAY AS AN
UPPER LOW MOVES DOWN FROM CANADA INTO THE NRN PLAINS AND A RIDGE
STARTS TO BUILD OFF THE EAST COAST AND OVER THE NEW ENGLAND STATES
IN RESPONSE. PERIODIC WEAK BITS OF MID/UPPER FORCING WILL PASS
ACROSS THE SOUTHEAST STATES DURING THIS TIME, ALONG WITH A LIGHT
EASTERLY FLOW AT LOW LEVELS, BUT NO REAL COLD AIR DAMMING SIGNAL
IS INDICATED UNTIL FRIDAY. THIS FAVORS KEEPING A LOW PRECIP PROB
EACH DAY WITH TEMPS CLOSE TO NORMAL, BUT WARM ENOUGH OVERNIGHT
TO KEEP ALL THE LIGHT PRECIP AS RAIN. ONCE WE GET INTO FRIDAY AND
BEYOND, CONFIDENCE ACTUALLY GOES ON AN UPWARD TREND. BOTH MODELS
HAVE THE SAME IDEA...THAT BEING A WEAK COASTAL LOW DEVELOPING
ON FRIDAY WITH A COLD AIR DAMMING WEDGE EAST OF THE BLUE RIDGE,
AND THE NEXT LOW PRESSURE SYSTEM ORGANIZING OVER THE PLAINS. WE
SEE REMARKABLY GOOD AGREEMENT WITH BRINGING ANOTHER STRONG COLD
FRONT EASTWARD FRIDAY NIGHT AND THEN MOVING IT ACROSS THE REGION
ON SATURDAY, BUT WE LIMIT OUR PRECIP PROB TO THE CHANCE RANGE FOR
THE TIME BEING AS THIS IS THE NEW DAY 7 AND THE TIMING COULD EASILY
SLIP. FORTUNATELY, TEMPS WILL REMAIN TOO WARM FOR ANY PRECIP-TYPE
ISSUES EXCEPT AT THE HIGHEST PEAKS OVER NEXT WEEKEND.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
AT KCLT AND ELSEWHERE: A STG SFC WEDGE WILL REMAIN PLACE ACROSS THE
AREA WHILE VERY LOW CIGS IN GOOD MOISTURE ADV CONTINUES THRU THE
OVERNIGHT. CIGS WILL REMAIN IN THE IFR RANGE WITH SOME TEMPORARY
MVFR OVER THE UPSTATE SC SITES POSSIBLE. VSBY WILL BE TRICKY AS
PERIODS OF -SHRA HAVE BEEN SCOURING OUT THE LLVLS. VFR VSBY
CURRENTLY OVER THE KCLT, KAVL, KAND, AND KGSP TERMINALS...BUT A
GENERAL DECREASE INTO MVFR OR IFR THRU THE OVERNIGHT IS EXPECTED AND
WILL ADDRESS WITH TEMPOS A STG COLD FRONT PUSHES IN FROM THE WEST
TONIGHT AND HAVE TIMED LLWS ACROSS ALL SITES BEG AFT 04Z ACROSS
THE MTNS AND ARND 06Z AT KCLT. SKIES WILL CLEAR UP RATHER QUICKLY
ARND NOON TO VFR CONDS...WITH MODERATE NW/LY TO SW/LY GUSTS
DEVELOPING AND CONTINUING THRU THE PERIOD.
OUTLOOK: EXPECT VFR TO PREVAIL THROUGH THE MIDDLE OF NEXT WEEK.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-00Z
KCLT HIGH 89% MED 76% MED 78% HIGH 100%
KGSP HIGH 84% MED 77% MED 75% HIGH 100%
KAVL MED 78% HIGH 87% HIGH 97% HIGH 100%
KHKY HIGH 85% HIGH 85% HIGH 81% HIGH 100%
KGMU HIGH 81% MED 65% MED 71% HIGH 100%
KAND MED 70% MED 71% HIGH 90% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK:
WWW.WEATHER.GOV/GSP/AVIATION
GSP WATCHES/WARNINGS/ADVISORIES
GA...FLOOD WATCH THROUGH SUNDAY MORNING FOR GAZ010-017-018-026-028.
NC...HIGH WIND WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR
NCZ033-049-050-501-503-505.
FLOOD WATCH THROUGH SUNDAY MORNING FOR NCZ033-035>037-048>053-
056>059-062>065-068>072-501>510.
WIND ADVISORY UNTIL 7 PM EST SUNDAY FOR NCZ048-051-052-058-059-
062>064.
WIND ADVISORY FROM 7 AM TO 7 PM EST SUNDAY FOR NCZ053-065.
WIND ADVISORY UNTIL 7 AM EST SUNDAY FOR NCZ033-049-050.
SC...FLOOD WATCH THROUGH SUNDAY MORNING FOR SCZ001>010.
SYNOPSIS...DEO
NEAR TERM...SBK/SGL
SHORT TERM...PM
LONG TERM...PM
AVIATION...SBK
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