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FXUS62 KGSP 210018
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
818 PM EDT MON APR 20 2026
WHAT HAS CHANGED
RED FLAG WARNING AND FIRE DANGER STATEMENT HAVE EXPIRED.
KEY MESSAGES
1. DRY BUT NOT AS WINDY TUESDAY. A FIRE DANGER STATEMENT MAY BE
NEEDED FOR NORTHEAST GEORGIA.
2. A FREEZE WARNING REMAINS IN EFFECT FOR THE NORTHERN MOUNTAINS
OF NC AND A FROST ADVISORY REMAINS IN EFFECT FOR REMAINDER OF NC
MOUNTAINS, THE NORTHERN FOOTHILLS, AND THE NORTHWEST PIEDMONT FROM
MIDNIGHT TONIGHT THROUGH 9 AM TUESDAY. FROST AND FREEZE CONDITIONS
COULD KILL CROPS, OTHER SENSITIVE VEGETATION AND POSSIBLY DAMAGE
UNPROTECTED OUTDOOR PLUMBING.
3. TEMPERATURES RETURN TO ABOVE NORMAL DURING THE LATTER HALF
OF THE WEEK, WHILE VERY DRY CONDITIONS CONTINUE. VERY LOW OR
EVEN CRITICAL AFTERNOON RH WILL ENHANCE FIRE DANGER THROUGH THE
END OF THE WORK WEEK. A FRONTAL SYSTEM WILL BRING RAIN CHANCES
NEXT WEEKEND.
DISCUSSION
KEY MESSAGE 1: DRY BUT NOT AS WINDY TUESDAY. A FIRE DANGER STATEMENT
MAY BE NEEDED FOR NORTHEAST GEORGIA.
DRY HIGH PRESSURE BUILDS INTO THE AREA ON TUESDAY. THIS WILL HELP
RELATIVE HUMIDITY VALUES DROP INTO THE 25 PERCENT RANGE ONCE AGAIN.
WINDS WILL BE MUCH LIGHTER; HOWEVER, A FIRE DANGER STATEMENT MAY
STILL BE NEEDED FOR NORTHEAST GEORGIA WHERE ONLY LOW RH IS NEEDED.
WITH BURN BANS IN EFFECT UNTIL FURTHER NOTICE ACROSS THE CAROLINAS,
OPEN BURNING OF ANY KIND IS ILLEGAL.
KEY MESSAGE 2: A FREEZE WARNING REMAINS IN EFFECT FOR THE NORTHERN
MOUNTAINS OF NC AND A FROST ADVISORY REMAINS IN EFFECT FOR REMAINDER
OF NC MOUNTAINS, THE NORTHERN FOOTHILLS, AND THE NORTHWEST
PIEDMONT FROM MIDNIGHT TONIGHT THROUGH 9 AM TUESDAY. FROST AND
FREEZE CONDITIONS COULD KILL CROPS, OTHER SENSITIVE VEGETATION
AND POSSIBLY DAMAGE UNPROTECTED OUTDOOR PLUMBING.
ANOTHER COOL NIGHT ACROSS THE REGION TONIGHT AS HIGH PRESSURE
SETTLES OVER THE CENTRAL APPALACHIANS. THE 12Z MODEL RUNS CONTINUE
TO SHOW GOOD RADIATIONAL COOLING CONDITIONS TONIGHT, WITH CLEAR SKY
AND VERY LIGHT N/NE SFC FLOW. GIVEN THAT LOW TEMPS THIS MORNING WERE
UNDER THE FORECAST LOWS BY SEVERAL DEGREES IN MANY SPOTS, WE WILL
MIX IN THE COOLER TEMPS FROM THE ENSEMBLE TO UNDERCUT THE NBM,
ESPECIALLY OVER THE NC PORTION. THE RESULT IS A LOW TEMP FCST ABOUT
TEN DEGREES BELOW NORMAL. THIS KEEPS MUCH OF THE NRN MOUNTAINS IN
THE FREEZE WARNING, SO NO CHANGES TO THAT PART. OUTSIDE OF THE NRN
MOUNTAINS, WE'RE STILL STRUGGLING TO GET MUCH IN THE WAY OF FROST IN
THE FCST USING OUR USUAL TECHNIQUES, POSSIBLY BECAUSE THE AIR MASS
REMAINS SO VERY DRY. BOTTOM LINE IS THAT OUR FROST ADVISORY WILL BE
LEFT ALONE FOR NOW.
TAKE STEPS NOW TO PROTECT TENDER PLANTS FROM THE COLD. IN-GROUND
SPRINKLER SYSTEMS SHOULD BE DRAINED. REMOVE HOSES AND COVER ABOVE-
GROUND PIPES.
TONIGHT SHOULD BE THE LAST NIGHT WITH THE FROST/FREEZE THREAT,
AS WE HAVE A WARMING TREND WITH THE SFC HIGH CENTER SHIFTING OFF
THE CAROLINA COAST ON TUESDAY AFTERNOON.
KEY MESSAGE 3: TEMPERATURES RETURN TO ABOVE NORMAL DURING THE LATTER
HALF OF THE WEEK, WHILE VERY DRY CONDITIONS CONTINUE. VERY LOW OR
EVEN CRITICAL AFTERNOON RH WILL ENHANCE FIRE DANGER THROUGH THE
END OF THE WORK WEEK. A FRONTAL SYSTEM WILL BRING RAIN CHANCES
NEXT WEEKEND.
HIGH PRESSURE WILL PERSIST OVER THE SOUTHEAST CONUS WEDNESDAY
THROUGH FRIDAY, INITIALLY SUPPORTED BY A LOW TO MIDLEVEL RIDGE ALOFT
AS UPPER RIDGE REMAINS CENTERED TO OUR WEST. AIRMASS MODIFICATION
AND GENERALLY LIGHT SW'LY WINDS WILL PROMOTE SLIGHT WARMING SUCH
THAT TEMPS REMAIN 7-10 DEGREES ABOVE NORMAL EACH AFTERNOON, BUT
THE WARMING OUTPACES MOISTURE RETURN AND MIN RH NEAR OR BELOW
THE CRITICAL 30% FIRE WEATHER THRESHOLD STILL IS EXPECTED EACH
AFTERNOON. MODELS STILL DEPICT A WEAK FRONT PUSHING SOUTH INTO THE
MID-ATLANTIC WEDNESDAY, EAST OF THE UPPER RIDGE, AND PUSHING INTO
OUR AREA LATE WED AFTERNOON OR EVENING. WHILE MOISTURE LOOKS MUCH
TOO PALTRY FOR THIS TO RESULT IN A MENTIONABLE POP, WINDS STILL
LOOK TO TURN NORTHWESTERLY AND DOWNSLOPE, SUGGESTING DEEP MIXING
AND A BRIEF RETURN OF WEST TO NORTHWEST WINDS, ALONG WITH SOME
GUST POTENTIAL OVER THE AREA WED AFTERNOON. THUS THAT DAY ARGUABLY
LOOKS THE MOST CRITICAL FOR FIRE WEATHER, THOUGH UNSEASONABLY HIGH
FIRE DANGER IS EXPECTED TO CONTINUE AT LEAST INTO THE WEEKEND,
WHEN PATTERN CHANGE APPEARS LIKELY TO OCCUR.
AN UPPER LOW WILL MOVE FROM THE PACIFIC COAST TO THE CANADIAN
PRAIRIE AND NORTHERN PLAINS STATES BY FRIDAY, SPAWNING CYCLOGENESIS,
REACTIVATING THE BOUNDARY TO OUR NORTH, AND PUSHING A COLD FRONT
INTO THE MISSISSIPPI VALLEY BY FRIDAY NIGHT. SOME SOLUTIONS DEPICT
A TRIPLE-POINT LOW DEVELOPING NEAR THE GREAT LAKES, AND THOSE
SOLUTIONS ARE FASTER IN BRINGING THE FRONT TO THE APPALACHIANS,
GENERALLY SATURDAY VERSUS SUNDAY. CONFIDENCE REMAINS RELATIVELY
LOW ON THE SPECIFICS, BUT THERE IS ENOUGH OF A CONSENSUS AS TO THE
PATTERN CHANGE FOR US TO FEATURE 40-60% POPS SATURDAY AND SUNDAY,
WITH THE HIGHEST VALUES BEING NEAR THE TN BORDER. TEMPS TREND
SLIGHTLY COOLER SUNDAY AND MONDAY WITH THE FRONT NEAR THE AREA
AND ENHANCED CLOUD COVER, ALONG WITH REDUCED THICKNESSES.
AVIATION /00Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: VFR AT ALL TERMINALS THROUGH THE PERIOD.
WINDS HAVE BEEN ALL OVER THE PLACE WITH A WEAK BOUNDARY MOVING
SOUTHEAST ACROSS THE REGION. HAVE STARTED WITH CURRENT WINDS THEN
TURN THEM LIGHT NE LATER IN THE EVENING. WIND BECOMES ENE NEAR
DAYBREAK THEN SW FOR THE AFTERNOON. KAVL KEEPS LOW END GUSTS EARLY
THIS EVENING THEN LIGHT OVERNIGHT, BEFORE PICKING BACK UP FROM THE N
AFTER DAYBREAK, THEN GOING S FOR THE AFTERNOON. ALTOCU OVER THE AREA
DISSIPATES DURING THE EVENING WITH SKC FOR THE REST OF THE PERIOD.
OUTLOOK: VFR AND DRY THROUGH THE WORK WEEK THANKS TO HIGH PRESSURE.
A FRONTAL SYSTEM MAY BRING SHOWERS AND ASSOCIATED RESTRICTIONS FOR
THE WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR
NCZ033-049-050.
FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR
NCZ035>037-048-051>053-056>059-062>065-501>507.
SC...NONE.
JCW/PM/RWH
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