511
FXUS62 KGSP 171143
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
643 AM EST MON FEB 17 2025
SYNOPSIS
DRY HIGH PRESSURE BUILDS IN TODAY AND LINGERS THROUGH TUESDAY.
WINTRY WEATHER IS LIKELY FOR PARTS OF THE AREA ON WEDNESDAY AS A
FAST-MOVING LOW PRESSURE SYSTEM PASSES ACROSS THE SOUTHEAST. DRY
HIGH PRESSURE RETURNS THURSDAY BRINGING VERY COLD WEATHER TO END THE
WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
1) A WIND ADVISORY REMAINS IN EFFECT FOR THE NORTHERN NC MTNS AND
ADJACENT ESCARPMENT ZONES, CONTINUING UNTIL NOON TODAY.
2) ISOLATED NW FLOW SNOW SHOWERS CONTINUE ALONG THE NC/TN BORDER
THRU DAYBREAK. LITTLE TO NO ADDITIONAL ACCUMULATIONS EXPECTED.
AS OF 6:30 AM EST MONDAY: NO MAJOR CHANGES NEEDED WITH THIS
UPDATE. FLURRIES CONTINUE TO AFFECT THE TN BORDER AREAS, WHILE AN
AREA OF CIRRUS HAS SPREAD OVER THE FORECAST AREA. BREEZY CONDITIONS
CONTINUE IN THE MOUNTAINS, AND THE NO CHANGES WERE MADE TO THE
WIND ADVISORY WITH THIS UPDATE.
OTHERWISE...DEEP SFC LOW CONTINUES TO SLOWLY DRIFT NE INTO THE
CANADIAN MARITIMES, WHILE A LARGE AREA OF ARCTIC HIGH PRESSURE
BUILDS IN FROM THE NORTHWEST. THE PRESSURE GRADIENT ACROSS THE
REGION IS SLOWLY WEAKENING, SO WINDS WILL FOLLOW SUIT. NOT SEEING
MANY GUSTS NEAR WIND ADVISORY CRITERIA IN THE MOUNTAINS, SO WILL
CANCEL MOST OF THE ADVISORY, EXCEPT IN THE NORTHERN MOUNTAINS WHERE
GUSTS REMAIN STRONG. MEANWHILE, STRATOCU DECK CONTINUES TO HOLD ON
ACROSS MUCH OF THE MOUNTAINS WITHIN THE WEST-NORTHWESTERLY FLOW,
WITH SOME CLOUDS STILL BREAKING CONTAINMENT IN THE NC FOOTHILLS AND
PIEDMONT. AN AREA OF CIRRUS WILL STREAM THRU THE AREA THIS MORNING,
BUT OVERALL, CLOUD COVER IS EXPECTED TO DECREASE TODAY. TEMPS WILL
BE ABOUT 5-8 DEG BELOW NORMAL, EXCEPT 10-15 DEG BELOW NORMAL ALONG
THE TN BORDER.
TONIGHT, WINDS BECOME LIGHT AS THE NOSE OF A LARGE AREA OF HIGH
PRESSURE WORKS FURTHER INTO THE REGION FROM THE NORTHWEST. CIRRUS
WILL INCREASE AND THICKEN WITHIN A WESTERLY UPPER JET STREAK
OVERNIGHT. MIN TEMPS ARE EXPECTED TO BE NEAR OR A CATEGORY BELOW
NORMAL.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 320 AM MON: A DRY FORECAST IS EXPECTED TUESDAY AS A SFC RIDGE
EXTENDS ACROSS THE OHIO VALLEY AND TO THE MID-ATLANTIC COAST. HIGHS
WILL BE UP TO 5 DEGREES BELOW NORMAL.
CONDITIONS CHANGE TUESDAY NIGHT INTO WEDNESDAY AS A SHORT WAVE
CARVES OUT AN UPPER LOW THAT MOVES INTO THE OH VALLEY WITH A SHORT
WAVE ROTATING AROUND THE LOW AND ACROSS THE AREA WEDNESDAY NIGHT. AT
THE SURFACE, MOISTURE BEGINS INCREASING AHEAD OF A GULF LOW AND
INVERTED TROUGH THAT MOVE TOWARD THE AREA TUESDAY NIGHT. THE LOW
MOVES ALONG THE GULF COAST TO THE SC COAST WEDNESDAY IN MILLER A
TYPE FASHION. DEEP MOISTURE AND FORCING QUICKLY RAMP UP WITH
CATEGORICAL POP EXPECTED ACROSS THE AREA THROUGH MUCH OF THE DAY
WEDNESDAY. THE ISSUE REMAINS THE AMOUNT AND DEPTH OF COLD AIR, QPF,
AND THE RESULTANT P-TYPES. GUIDANCE OVERALL HAS COME IN WITH LOWER
QPF GIVEN THE FAST MOVEMENT OF THIS SYSTEM. THERMAL PROFILES ALSO
DIFFER WITH WITH SOME HAVING DEEP COLD AIR AS FAR SOUTH AS THE I-85
CORRIDOR AND SOME CLOSER TO THE I-40 CORRIDOR. GIVEN THE CONTINUED
UNCERTAINTY WITH QPF AND COLD AIR, WILL HOLD OFF ON ANY WATCH
ISSUANCES AT THIS TIME. IN FACT, THE CHANCE OF WARNING CRITERIA SNOW
OR ICE HAS FALLEN TO LESS THAN 30 PERCENT FOR OUR AREA. PRECIP MAY
START OUT AS SNOW OR A RAIN/SNOW MIX FOR THE I-85 CORRIDOR WITH
MAINLY SNOW FOR THE I-40 CORRIDOR INTO THE NORTHERN MOUNTAINS AND
HIGH ELEVATIONS OF THE REST OF THE MOUNTAINS. AS A WARM NOSE
DEVELOPS, PRECIP CHANCES TO RAIN FOR THE I-85 CORRIDOR AND
SLEET/SNOW FOR I-40. MAINLY SNOW CONTINUES FOR THE NORTHERN
MOUNTAINS AND HIGH ELEVATIONS OF THE REST OF THE NC MOUNTAINS. A
BRIEF PERIOD OF FREEZING RAIN MAY MIX IN ALONG THE I-77 CORRIDOR AS
RAIN CHANGES BACK TO SNOW EARLY IN THE EVENING. AN OVERALL CHANGE TO
SNOW BEGINS BUT PRECIP CHANCES ARE MOVING OUT AS THE LOW MOVES UP
THE CAROLINA COAST. PRECIP THEN ENDS OUTSIDE OF THE MOUNTAINS
OVERNIGHT AS NW FLOW SNOW SHOWERS BEGIN ACROSS THE MOUNTAINS.
AS YOU CAN SEE, THIS IS A COMPLICATED WEATHER SCENARIO AND EVEN
SMALL CHANGES IN TEMPS OR QPF COULD HAVE A BIG DIFFERENCE IN P-TYPES
AND ACCUMS. FOR NOW, HAVE GONE NEAR THE LOWER END OF THE GUIDANCE
BLEND FOR TEMPS GIVEN THE COLD AIR DAMMING. THIS GIVES US 1 TO 2
INCHES OF SNOW FOR THE I-40 CORRIDOR DROPPING TO HALF AN INCH OR
LESS FOR THE I-85 CORRIDOR AND A DUSTING AT BEST TO THE SOUTH. FOR
THE NC MOUNTAINS, GENERALLY AN INCH OR LESS FOR THE CENTRAL AND
SOUTHERN VALLEYS AND 1 TO 2 INCHES FOR THE NORTHERN VALLEYS WITH 2 TO
4 INCHES FOR THE HIGHER ELEVATIONS. GENERALLY A LIGHT GLAZE OF ICE
IS EXPECTED WHERE FREEZING RAIN DEVELOPS, MAINLY THE I-77 CORRIDOR
AND PORTIONS OF THE BLUE RIDGE ESCARPMENT. OF COURSE, THIS IS
SUBJECT TO CHANGE, SO CONTINUE TO MONITOR THE FORECAST.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 240 AM MON: SOME FLURRIES COULD LINGER THURSDAY MORNING ALONG
THE TN BORDER BUT ANY ACCUMULATING SNOW SHOULD BE OVER BY THEN. A
VERY COLD HIGH PRESSURE AREA BUILDS IN THU AND THU NITE WITH TEMPS
AROUND 20 DEGREES BELOW NORMAL. TEMPERATURES MODERATE FRI AND FRI
NITE AS THE CENTER OF THE ASSOCIATED DRY HIGH PRESSURE MOVES INTO
THE AREA. STILL, OUR DEFINITION OF A "COLD WAVE" MAY BE MET THURSDAY-
FRIDAY. THE HIGH SLOWLY TRANSLATES ACROSS THE AREA THROUGH SUNDAY,
WITH TEMPERATURES MODERATING TO A LITTLE BELOW NORMAL. GUIDANCE
SHOWS THE POTENTIAL FOR ANOTHER GULF LOW TO MOVE NEAR THE AREA
SUNDAY. HOWEVER, OPERATIONAL AND ENSEMBLE GUIDANCE DIFFER GREATLY ON
THE LOW TRACK AND ANY ASSOCIATED PRECIP CHANCES. GIVEN THE
UNCERTAINTY, HAVE KEPT THE FORECAST DRY FOR NOW.
AVIATION /12Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS TO PREVAIL THRU THE TAF
PERIOD, EXCEPT FOR SOME MVFR CIGS AT KAVL IN THE FIRST COUPLE HOURS
OF THE 12Z TAF. THE STRATOCU ALONG THE TN LINE SHOULD GRADUALLY
DECREASE THRU THE MORNING HOURS, LEAVING JUST CIRRUS STREAMING BY
TODAY. WINDS WILL REMAIN GUSTY AT KAVL THRU THE DAY, GRADUALLY
WEAKENING AND LOSING GUSTS THIS EVENING. GENERALLY LIGHT WINDS
ELSEWHERE, ALTHOUGH, CANNOT RULE OUT A FEW BRIEF GUSTS AT KGSP
AND KHKY AN HOUR OR TWO AFTER SUNRISE.
OUTLOOK: EXPECT VFR CONDITIONS TO CONTINUE THRU TUESDAY. A
QUICK-MOVING LOW PRESSURE SYSTEM MAY BRING WINTRY PRECIPITATION
AND RESTRICTIONS TO THE REGION ON WEDNESDAY. DRY HIGH PRESSURE
RETURNS THURSDAY AND CONTINUES THRU THE END OF THE WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...WIND ADVISORY UNTIL NOON EST TODAY FOR NCZ033-049-050-501-503-
505.
SC...NONE.
SYNOPSIS...RWH
NEAR TERM...ARK
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...ARK
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