887
FXUS62 KRAH 160738
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
235 AM EST THU JAN 16 2025
SYNOPSIS
ARCTIC HIGH PRESSURE WILL BUILD ACROSS NC TONIGHT. A DRY FRONTAL
ZONE WILL THEN WAVER OVER THE CAROLINAS THURSDAY THROUGH FRIDAY.
.NEAR TERM /TODAY AND TONIGHT/
AS OF 235 AM THURSDAY...
..MODERATING TO NEAR NORMAL WITH BREEZY CONDITIONS
SURFACE HIGH PRESSURE ACROSS THE AREA WILL SINK SOUTH TOWARDS THE
NORTHERN GULF COAST AND DEEP SOUTH, WHICH WILL ALLOW SURFACE WINDS
TO BECOME SWLY AFTER DAYBREAK. WINDS WILL INCREASE AHEAD OF AN
AMPLIFYING NORTHERN STREAM MID-LEVEL TROUGH THAT WILL SWING THROUGH
THE AREA DURING THE AFTERNOON. EXPECT FREQUENT SWLY GUSTS OF 20-30
MPH BEGINNING FROM LATE MORNING/MIDDAY AND CONTINUING INTO THE MID
AFTERNOON BEFORE DIMINISHING. THE UPPER TROUGH WILL ALSO LEAD TO A
FLEETING PERIOD OF 5-10KFT BROKEN CEILINGS ACROSS THE NORTHERN HALF
OF THE FORECAST AREA. LOW-LEVEL THICKNESSES REBOUND ~30 METERS FROM
YESTERDAY, WHICH SHOULD TRANSLATE IN ~10 DEGREES OF WARMING. HIGHS
RANGING FROM MID/UPPER 40S NORTH TO LOWER 50S SOUTH.
GUSTS WILL SUBSIDE AND SKIES WILL CLEAR OUT IN THE EVENING FOLLOWING
THE PASSAGE OF THE UPPER TROUGH. WINDS WILL BACK TO NWLY AS THE
SURFACE TROUGH/WEAK FRONT MOVES EAST AND OFF THE COAST DURING THE
LATE EVENING. NOT AS COLD. LOWS 25-30.
SHORT TERM /FRIDAY AND FRIDAY NIGHT/
AS OF 235 AM THURSDAY...
TRANSITORY SFC HIGH AND SHORTWAVE RIDGING ALOFT BRIEFLY BUILDS EAST
ACROSS THE CAROLINAS AND THEN QUICKLY OFFSHORE FRIDAY EVENING/NIGHT,
AHEAD OF A DEAMPLIFYING SOUTHERN STREAM SHORTWAVE TROUGH THAT
ADVANCES INTO THE SOUTHERN APPALACHIANS AROUND DAYBREAK SATURDAY.
SUNNY/MOSTLY CLEAR SKIES WILL PREVAIL THROUGH THE EVENING. GIVEN
LITTLE TO THERMAL ADVECTION INTO THE AREA, LOW-LEVEL THICKNESSES
FRIDAY ARE SIMILAR TO THURSDAY/TODAY. HIGHS AGAIN RANGING FROM
MID/UPPER 40S NORTH TO LOWER 50S SOUTH.
CLOUDS WILL THICKEN FROM THE WEST AFTER MIDNIGHT. WITH THE STRONGEST
MOISTURE TRANSPORT EXPECTED TO REMAIN WELL SOUTH OF THE AREA, IN
CLOSER PROXIMITY TO A WEAK SURFACE WAVE/LOW MOVING THROUGH THE DEEP
SOUTH, RAIN CHANCES AND PRECIP AMOUNTS ACROSS THE AREA ARE LOOKING
INCREASINGLY MINIMAL. CANNOT RULE OUT SOME VERY LIGHT PRECIP AND
SLIGHT CHANCES MOVING INTO THE FAR NW PIEDMONT TOWARDS DAYBREAK.
CURRENTLY, DON'T EXPECT ANY P-TYPE CONCERNS WITH PARTIAL THICKNESSES
AND SFC WET-BULBS INDICATING RAIN AT THE SFC. LOWS RANGING FROM
LOWER 30S ACROSS THE NORTHERN COASTAL PLAIN WHERE CLOUDS WILL BE
LATEST TO ARRIVE, TO MID 30S ELSEWHERE.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
AS OF 315 PM WEDNESDAY...
HIGHLIGHTS:
-THERE ARE TWO POTENTIAL WEATHER SYSTEMS THAT COULD
CREATE WINTRY WEATHER BETWEEN FRIDAY AND THE MIDDLE TO LATE NEXT
WEEK, WITH AN ARCTIC BLAST IN BETWEEN.
-THE FIRST WEATHER SYSTEM COMES ON SATURDAY WITH A HIGH PROBABILITY
OF RAIN, FOLLOWED BY THE POTENTIAL FOR ANOTHER PERIOD OF LIGHTER
RAIN THAT COULD MIX WITH SOME SNOW, ESPECIALLY ACROSS NORTHERN AREAS
ON SUNDAY.
-BEHIND THIS SYSTEM WILL BE AN ARCTIC BLAST THAT MAY RIVAL
TEMPERATURES IN LATE DECEMBER 2022 WHEN LOW TEMPERATURES REACHED THE
SINGLE DIGITS AND HIGHS WERE IN THE 20S.
-THE NEXT WEATHER SYSTEM HAS THE POTENTIAL TO BE A COASTAL LOW WITH
WINTRY PRECIPITATION ACROSS INTERIOR NORTH CAROLINA MID TO LATE
WEEK. HOWEVER, CONFIDENCE IS VERY LOW AT THIS POINT DUE TO
SIGNIFICANT DIFFERENCES IN MODEL RUNS REGARDING HOW FAR EAST OR WEST
THE LOW TRACKS
MORE DETAILS:
THE OVERALL WEATHER PATTERN WILL FEATURE A BRIEF PERIOD OF SHORTWAVE
RIDGING ON FRIDAY AHEAD OF THE REESTABLISHMENT OF A VERY DEEP AND
COLD LONGWAVE TROUGH OVER THE EASTERN US THAT PERSISTS THROUGH NEXT
WEEK. ON THE FRONT END, A LEAD SOUTHERN STREAM SHORTWAVE IS
FORECAST TO RACE ACROSS THE DEEP SOUTH ON FRIDAY AND BRING
WIDESPREAD RAIN TO THE REGION SATURDAY. MODELS HAVE BEEN CONSISTENT
AND INDICATING THAT THE HEAVIER QPF WILL SPREAD ACROSS GEORGIA AND
SOUTH CAROLINA, MORE ASSOCIATED WITH A WAVE OF LOW PRESSURE TRACKING
ACROSS A SLOWLY NORTHWARD RETREATING POLAR FRONT AND EVENTUALLY
DEVELOPING INTO A SURFACE LOW OFF THE CAROLINA COAST SATURDAY NIGHT,
WHILE THERE IS A DRYING TREND AS THE PRECIPITATION REACHES NORTH
CAROLINA INTO VIRGINIA. OVERALL QPF IS FORECAST TO BE IN THE 0.25-
0.5 RANGE ON SATURDAY.
BEHIND THIS AREA OF RAIN THE ARCTIC FRONT IS FORECAST TO CROSS
CENTRAL NORTH CAROLINA ON SUNDAY. MODELS HAVE BEEN FAIRLY CONSISTENT
IN SHOWING A WAVE OF LOW PRESSURE DEVELOPING ALONG THE FRONT IN
RESPONSE TO THE DEEP UPPER LEVEL TROUGH, WHICH CONSEQUENTLY CAUSES
PRECIPITATION TO BREAK OUT OVER THE PIEDMONT SUNDAY OR SUNDAY NIGHT.
THIS IS TYPICALLY A SCENARIO WHERE THE ARRIVAL OF COLD AIR THAT
COULD CAUSE A CHANGE OVER TO SNOW IS TOO LATE, BUT GIVEN THE
POTENTIAL FOR A WAVE OF LOW PRESSURE AND STRONG DEEP LAYER LIFT, IT
SEEMS MORE PLAUSIBLE THAT A MIX OF RAIN AND SNOW COULD DEVELOP,
ESPECIALLY ACROSS COUNTIES CLOSER TO VIRGINIA. THE GFS EVEN
INDICATES SOME LOCALLY HIGHER QPF NEAR A QUARTER OF AN INCH ACROSS
NORTHEAST NORTH CAROLINA, SO THERE ARE DETAILS THAT WILL BE WORTH
WATCHING OVER THE NEXT SEVERAL MODEL RUNS.
FOLLOWING THE ARCTIC FRONT, THE ARCTIC AIR MASS USHERED IN AHEAD OF
A 1050 MB HIGH-PRESSURE OVER THE CENTRAL PLAINS IS FORECAST TO HAVE
THICKNESSES THAT BOTTOM OUT BELOW 1230 M. GUIDANCE IS INDICATING
LOWS WELL INTO THE TEENS IF NOT NOT SINGLE DIGITS IN SOME AREAS BY
TUESDAY AND HIGHS IN THE 20S.
THE NEXT BIG QUESTION IS HOW SHORTWAVES MOVING THROUGH THE LONGWAVE
TROUGH COULD CAUSE CYCLOGENESIS IN THE GULF OF MEXICO OR ALONG THE
SOUTH EAST COAST, AND HOW FAR WEST PRECIPITATION EXTENDS INTO A
SIGNIFICANTLY COLD AIR MASS ACROSS THE CAROLINAS. MODELS HAVE BEEN
BACK-AND-FORTH BETWEEN OFFSHORE PRECIPITATION AND PRECIPITATION
EXTENDING WELL INTO NORTH CAROLINA, WITH ALMOST REGULAR FLIP-
FLOPPING BETWEEN MODEL CYCLES. PROBABILISTIC FORECASTS BASICALLY
SHOW AT LEAST A SLIGHT CHANCE OF SNOW BETWEEN TUESDAY AND THURSDAY,
WHICH HIGHLIGHTS THE UNCERTAINTY, AS IS VERY UNLIKELY TO SNOW FOR
THAT LONG. INSTEAD, THE MODELS ARE HAVING A HARD TIME, FOCUSING ON
ONE SPECIFIC PERIOD OF PRECIPITATION. FOR NOW, WE WILL CONTINUE TO
INDICATE A SLIGHT CHANCE OF SNOW WITH THE CAVEAT THAT THIS WILL
DEFINITELY CHANGE AND THE SYSTEM COULD HAVE ANYWHERE FROM NO IMPACT
TO SIGNIFICANT IMPACT.
AVIATION /06Z THURSDAY THROUGH MONDAY/
AS OF 1225 AM THURSDAY...
24 HOUR TAF PERIOD: HIGH CONFIDENCE VFR CONDITIONS WILL PREVAIL
THROUGH THE TAF PERIOD.
SURFACE HIGH PRESSURE ACROSS THE AREA WILL SINK SOUTH TOWARDS THE
NORTHERN GULF COAST AND DEEP SOUTH, WHICH WILL ALLOW SURFACE WINDS
TO BECOME SWLY AFTER DAYBREAK. WINDS WILL INCREASE AHEAD OF AN
AMPLIFYING NORTHERN STREAM MID-LEVEL TROUGH THAT WILL SWING THROUGH
THE AREA DURING THE AFTERNOON. EXPECT FREQUENT SWLY GUSTS OF 20-
30KTS BEGINNING MIDDAY AND CONTINUING INTO THE MID AFTERNOON BEFORE
DIMINISHING. THE UPPER TROUGH WILL ALSO LEAD TO A FLEETING PERIOD OF
5-10KFT BROKEN CEILINGS ACROSS THE NORTHERN TERMINALS DURING THE
AFTERNOON.
GUSTS WILL SUBSIDE AND SKIES WILL CLEAR OUT IN THE EVENING. A 30-
40KT WLY LLJ AT 2000 FT AGL WILL RESULT IN A CHANCE OF LOW-LEVEL
WIND SHEAR THROUGH AROUND 06Z, BEFORE DIMINISHING.
OUTLOOK: DRY VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY. A COUPLE OF
FRONTAL SYSTEMS AND ACCOMPANYING RAIN, SUB-VFR FLIGHT RESTRICTIONS,
AND MARGINAL LOW-LEVEL WIND SHEAR ACROSS CENTRAL NC THIS WEEKEND.
FIRE WEATHER
AS OF 235 AM THURSDAY...
STRENGTHENING SWLY SURFACE WINDS WITH AFTERNOON GUSTS BETWEEN 20-30
MPH WITH MIN RH BETWEEN 25-35 PERCENT MAY LEAD TO INCREASED FIRE
DANGER THIS AFTERNOON. FUEL MOISTURE ON THE 1 HOUR AND 10 HOUR TIME
SCALE DO NOT LOOK OVERLY DRY. HOWEVER, WILL COORDINATE WITH THE NCFS
FOR ANY FIRE CONCERNS.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...MWS
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...BLS
AVIATION...CBL/MWS
FIRE WEATHER...CBL
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