071
FXUS62 KGSP 290803
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
303 AM EST MON NOV 29 2021
SYNOPSIS
HIGH PRESSURE WILL CONTROL OUR WEATHER THROUGH THE BETTER PART OF
THE WEEK, WITH A WARMING TREND AFTER WEDNESDAY. THE NEXT CHANCE
FOR RAIN MAY NOT COME UNTIL NEXT WEEKEND WHEN THE NEXT FRONT MAY
IMPACT THE REGION.
NEAR TERM /THROUGH TONIGHT/
AS OF 220 AM EST MONDAY: A DEEP TROUGH AXIS IS SITUATED EAST OF THE
FORECAST AREA, ROUGHLY ALIGNED WITH THE COAST AND GRADUALLY DRIFTING
EAST, AS A DECAYING COLD FRONT SAGS SOUTH AND EAST OF THE CAROLINA
PIEDMONT. SATELLITE IMAGERY INDICATES A SLUG OF UPSTREAM MOISTURE
AND IN THE LAST HOUR OR TWO HAS BEGUN TO SHOW EVIDENCE OF THE
EXPECTED OROGRAPHIC CIRRUS FORMATION JUST TO THE EAST OF THE
APPALACHIANS. A FEW WIND GUSTS HAVE POPPED UP IN STATION
OBSERVATIONS, BUT THE BRUNT OF THE WIND GUST THREAT HAS NOT YET
MATERIALIZED.
HEIGHTS SHOULD GENTLY RISE THROUGH THE PERIOD AS THE TROUGH
CONTINUES TO LIFT EASTWARD, GIVING WAY TO BROAD RIDGING OUT OF THE
HIO VALLEY. 850MB FLOW LOOKS TO PEAK AT ABOUT 40-45KTS IN THE NEXT
FEW HOURS AS DEEP CAA BUILDS IN BEHIND THE FRONT, BUT THIS IS LIKELY
TO AFFECT ONLY THE HIGHER ELEVATIONS IN THE APPALACHIANS, AS THE
BOUNDARY LAYER SHOULD BE DECOUPLED ENOUGH TO PREVENT THOSE WINDS
FROM MIXING DOWN THE SURFACE. A MODEST 6-7MB PRESSURE GRADIENT
ACROSS THE SPINE OF THE MOUNTAINS SHOULD STEADILY DISSIPATE THROUGH
THE MORNING AND EARLY AFTERNOON, SO THE SECOND HALF OF MONDAY SHOULD
SEE WIND GUSTS DROP OFF.
WHILE CAMS DEPICT SOME DEGREE OF LEE TROUGHING WELL
INTO THE LATE MORNING MONDAY, PROFILES ACROSS THE REGION ARE TOO DRY
FOR THIS TO MANIFEST AS ANYTHING MORE THAN SOME SCATTERED MID- AND
UPPER-LEVEL CLOUDS. DOWNSLOPING FLOW SHOULD BOOST AFTERNOON TEMPS
TOWARD THE HIGH END OF GUIDANCE, THOUGH THIS WILL STILL BE 2-3
CATEGORIES BELOW NORMAL, AS WELL AS FURTHER DRYING THE MOISTURE-
STARVED CP AIR FILTERING IN FROM THE NORTHWEST. AFTERNOON RHS WILL
LIKELY DROP INTO THE MID/UPPER 20S ACROSS THE PIEDMONT AND UPSTATE,
WELL INTO THE AREA OF CONCERN FOR FIRE DANGER; LUCKILY, THE OVERLAP
BETWEEN THE DRIEST HUMIDITIES AND GUSTIEST WINDS WILL BE MINIMAL IN
BOTH SPACE AND TIME. BY EVENING, NW FLOW AND ACCOMPANYING CAA
SHOULD CEASE, AS LOW-LEVEL FLOW GRADUALLY TURNS SW OVERNIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 1225 AM EST MONDAY...THE WEAKLY POSITIVE PNA PATTERN LOOKS
LIKE IT WILL CONTINUE INTO THE MIDDLE OF THE WEEK, WITH THE WESTERN
CAROLINAS REMAINING NEAR THE BOTTOM OF A BROAD LOW-AMPLITUDE
MID/UPPER TROF. FOR THE MOST PART, THIS WILL KEEP OUR WEATHER FAIR,
WHILE THE FAVORABLE ORIENTATION OF A SFC RIDGE ALONG THE GULF
COAST EXTENDING OFF THE SOUTHEAST COAST SHOULD PROVIDE FOR WEAK
WARM ADVECTION AND MOISTURE ADVECTION. AS A RESULT, TEMPS WILL
CLIMB ABOVE NORMAL FOR TUESDAY AND WEDNESDAY. MORE IMPORTANTLY,
ENOUGH OF AN UPWARD BUMP IN DEWPT IS EXPECTED TO BRING AFTERNOON
MIN RH INTO THE 30 PCT RANGE TUESDAY AND 40 PCT RANGE WEDNESDAY,
TEMPORARILY ALLEVIATING SOME OF OUR FIRE WEATHER CONCERNS. WHERE
THIS COULD ALL GO WRONG IS ACROSS THE NRN TIER, OWING TO A STREAM OF
MID-LEVEL VORTS MOVING PAST ACROSS THE OH VALLEY/MID-ATLANTIC. MODEL
GUIDANCE KEEPS THIS ACTIVITY TO OUR NORTH THROUGH THE PERIOD,
BUT IT WOULDN'T TAKE MUCH OF A SOUTHWARD SHIFT TO BRING SOME OF
THE FORCING DOWN INTO OUR AREA, ESPECIALLY WITH THE FINAL WAVE IN
THE TRAIN WEDNESDAY NIGHT. GUIDANCE DEVELOPS SOME WESTERLY UPSLOPE
PRECIP AROUND DAYBREAK THURSDAY, BUT JUST TO OUR NORTH. AT ANY RATE,
TEMPS SHOULD BE WARM ENOUGH THAT ANY PRECIP WOULD BE LIGHT RAIN.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 235 AM EST MONDAY...THE SECOND HALF OF THE WEEK CONTINUES
TO FEATURE A WARMING TREND AS THE UPPER PATTERN DEAMPLIFIES AND
HEIGHTS RISE OVER THE CAROLINAS. WE END UP IN THE FAST-MOVING
CONFLUENCE OF THE SPLIT FLOW ALOFT BY FRIDAY. WHETHER OR NOT
THIS PERMITS A DRY COLD FRONT TO PASS LATE IN THE WEEK MIGHT NOT
MATTER MUCH. TEMPS WILL BE WELL ABOVE NORMAL, PERHAPS MORE THAN
TEN DEGREES, FOR HIGHS THURSDAY AND FRIDAY, WITH HIGH PRESSURE
IN CONTROL OVER THE SOUTHEAST. SOME ENERGY COMING THROUGH THE SRN
BRANCH OF THE SPLIT COMPLICATES THE ISSUE, BUT CONFIDENCE IS LOW AS
THESE FEATURES ARE DIFFICULT TO PIN DOWN WITH THE TIMING. A CHANCE
OF PRECIP WILL DEVELOP OVER THE MTNS FRIDAY NIGHT AND SATURDAY,
WITH TEMPS TOO WARM FOR ANYTHING BUT RAIN. HOW THE WEAK SRN STREAM
SYSTEM INTERACTS WITH A NRN STREAM SHORT WAVE HAS AN IMPACT ON THE
FCST FOR THE REST OF NEXT WEEKEND. THE GFS TAKES A SFC LOW ACROSS
THE CUMBERLAND PLATEAU AND CENTRAL APPALACHIANS WHICH WOULD BRING
A SWATH OF PRECIP INTO THE FCST AREA SUNDAY NIGHT, WHILE THE ECMWF
FAVORS A LESS-INTERACTIVE SOLUTION WITH LOW PRESSURE ALONG THE GULF
COAST BY MONDAY MORNING AND SFC HIGH PRESSURE IN A FAVORABLE COLD
AIR DAMMING CONFIGURATION. EITHER WAY, LIGHT PRECIP WOULD BE FALLING
BY DAYBREAK MONDAY. PATTERN RECOGNITION DOES NOT FAVOR ANYTHING
BUT RAIN, SO THE HIGH-ELEVATION MIX THAT MIGHT APPEAR OVER THE
MTNS COMES OUT AS SOMETHING OF A LOW CONFIDENCE ARTIFACT. CHANGES
ARE LIKELY.
AVIATION /08Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: NW FLOW HAS BEGUN IN EARNEST AT ALL THE TAF
SITES, AS DRY HIGH PRESSURE BUILDS IN BEHIND A DEPARTING COLD FRONT.
WIND SPEEDS SHOULD BE SLIGHTLY ELEVATED OVERNIGHT, WITH A CHANCE
FOR GUSTING AT KAVL AND EVEN TO SOME EXTENT AT KGSP AND KGMU OWING
TO GAP WINDS. THE GUST THREAT SHOULD GRADUALLY DIMINISH BY LATE
MORNING/EARLY AFTERNOON MONDAY, AS WINDS OVERALL DIE DOWN AND BECOME
MORE WESTERLY. SOME OROGRAPHIC CIRRUS IS STILL IN STORE FOR THE LEE
OF THE MOUNTAINS OVERNIGHT AND INTO MONDAY MORNING, BUT ANY MINIMAL
CEILINGS WHICH FORM WILL BE VFR BY A LONG SHOT. SKIES SHOULD GO TO
SKC BY EARLY AFTERNOON AT ALL THE TAF SITES, AND TOWARD MONDAY
EVENING, A WIND SHIFT TO SW MAY BE IN STORE. WINDS SHOULD REMAIN
LIGHT THROUGH THE END OF THE PERIOD.
OUTLOOK: DRY HIGH PRESSURE AND VFR CONDITIONS WILL PERSIST THROUGH
TUESDAY NIGHT. ANOTHER DRY FRONT MAY ARRIVE FROM THE NORTH
WEDNESDAY THROUGH THURSDAY, AND LINGER NEARBY THROUGH FRIDAY,
BUT WITH RESTRICTIONS VERY UNLIKELY GIVEN LIMITED MOISTURE.
FIRE WEATHER
AN ELEVATED FIRE RISK WILL CONTINUE INTO MONDAY. RELATIVE HUMIDITY
SHOULD DROP WELL INTO 20S WITH DOWNSLOPE WARMING, WHILE FUELS REMAIN
VERY DRY. WINDS MAY BE GUSTY ON MONDAY, BUT MAINLY OVER THE
MOUNTAINS AND ALSO BRIEFLY ACROSS THE PIEDMONT MID TO LATE MORNING
WHEN MIXING STARTS, YET WINDS WILL LIKELY NOT OVERLAP WITH THE LOWER
AFTERNOON RH VALUES. THUS, A FIRE DANGER STATEMENT (FDS) REMAINS IN
EFFECT FOR NE GA AND WESTERN NC MONDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...FIRE DANGER STATEMENT FROM 10 AM EST THIS MORNING THROUGH THIS
AFTERNOON FOR GAZ010-017-018-026-028-029.
NC...FIRE DANGER STATEMENT FROM 10 AM EST THIS MORNING THROUGH THIS
EVENING FOR NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510.
SC...NONE.
SYNOPSIS...PM
NEAR TERM...MPR
SHORT TERM...PM
LONG TERM...PM
AVIATION...MPR
FIRE WEATHER...
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page