305
FXUS62 KRAH 181918
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
218 PM EST FRI JAN 17 2025
SYNOPSIS
AN AREA OF LOW PRESSURE AND ASSOCIATED WARM FRONT WILL LIFT THROUGH
THE AREA ON SUNDAY. ARCTIC HIGH PRESSURE WILL BUILD IN BEHIND A COLD
FRONT LATE SUNDAY AFTERNOON AND BRING BITTER COLD TEMPERATURES INTO
THE REGION THROUGH THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 210 PM SATURDAY...
* MILD OVERNIGHT TEMPERATURES AND AREAS OF FOG EXPECTED TONIGHT.
* RAIN SPREADS BACK INTO THE AREA EARLY SUNDAY MORNING.
REGIONAL SATELLITE AND RADAR DATA SHOW THE BACK EDGE OF MID/UPPER
LEVEL CLOUDS AND PRECIPITATION HAS ALREADY PUSHED THROUGH THE TRIAD
AND IS RAPIDLY APPROACHING THE TRIANGLE AS OF 19Z. IN ITS WAKE,
MAINLY LOW CLOUDS WHICH WILL CONTINUE TO ERODE THROUGH THE LATE
AFTERNOON HOURS AND PA FEW HOURS OF PARTLY CLOUDY TO MOSTLY SUNNY
CONDITIONS. A LULL IN PRECIPITATION CHANCES IS EXPECTED TO CONTINUE
THROUGH THE EVENING HOURS AS VERY DRY MID-LEVEL AIR BEHIND THE
DEPARTING SHORTWAVE TROUGH SPREADS OVER THE AREA.
CLOUD COVER IS EXPECTED TO RETURN THROUGH THE EVENING AND OVERNIGHT
HOURS AS THE BOUNDARY LAYER BEGINS TO COOL. AREAS OF FOG WILL BE
POSSIBLE TONIGHT INTO EARLY SUN MORNING AS THIS CLOUD LAYER LOWERS
THROUGH THE OVERNIGHT PERIOD, BUT ALSO ENHANCED BY SURFACE MOISTURE
ADVECTION WITH THE APPROACHING SURFACE LOW AND ASSOCIATED WARM
FRONT. THE MOST LIKELY LOCATIONS THAT MAY EXPERIENCE DENSE FOG
TONIGHT WILL BE ALONG AND JUST NORTH OF THE NORTHWARD RETREATING
WARM FRONT AND HOW THAT PROGRESSES THROUGH THE OVERNIGHT PERIOD.
TONIGHT WILL BE THE LAST NIGHT OF MILD OVERNIGHT TEMPERATURES BEFORE
DANGEROUS COLD TEMPERATURES SPILL ACROSS THE AREA BEHIND THE PASSAGE
OF AN ARCTIC FRONT ON SUNDAY.
SHORT TERM /SUNDAY AND SUNDAY NIGHT/
AS OF 340 AM SATURDAY...
...WIDELY SCATTERED RAIN SHOWERS THROUGH THE AFTERNOON WITH ARCTIC
AIR ARRIVING LATE SUNDAY...
THE NEXT SHORTWAVE TROUGH DIVING SEWD THROUGH THE BASE OF THE DEEP
LONG WAVE TROUGH WILL PROVIDE A GLANCING SHOT OF MOISTURE AND LIFT
ACROSS THE AREA. AS THE SUBTROPICAL AND POLAR JET STREAMS CONVERGE
AND STRENGTHEN OVER THE REGION, THE INCOMING COLD FRONT WILL
TEMPORARILY SLOW DOWN/STALL WITH A WEAK AREA OF LOW PRESSURE
DEVELOPING OVER THE CAROLINAS SUNDAY MORNING. THE FRONT WILL
PROGRESS SLOWLY EAST AND OFFSHORE DURING THE EVENING WITH THE LOW
DEEPENING AS IT TRACKS UP THE MID-ATLANTIC COAST.
THE BETTER RAIN CHANCES LOOK TO OCCUR OVERNIGHT/EARLY MORNING HOURS,
FOLLOWED BY MULTIPLE ROUNDS OF WIDELY SCATTERED RAIN SHOWERS THROUGH
THE AFTERNOON, LIMITED IN COVERAGE AND QPF AMOUNTS DUE TO
ENTRAINMENT OF MID-LEVEL DRY AIR. THE DRYING ALOFT WILL ALSO
SIGNIFICANTLY DECREASE CHANCES OF ICE IN THE CLOUD TO SUPPORT A
CHANGE-OVER TO SNOW ACROSS THE NORTHERN COUNTIES DURING THE LATE
AFTERNOON/EARLY EVENING AS THE ARCTIC AIR POURS INTO THE AREA. THUS,
WILL NOT CARRY ANY SNOW ACCUMULATIONS.
HIGHS SUNDAY WILL DEPEND ON THE ACTUAL TIMING OF THE FRONTAL
PASSAGE. HOWEVER, GIVEN THE SLOWNESS OF THE PASSAGE, EXPECT A LARGE
TEMPERATURE GRADIENT ACROSS THE AREA, RANGING FROM MID/UPPER 40S
NORTH TO LOWER 60 SE. TEMPERATURES WILL CRASH FROM NW TO SE DURING
THE AFTERNOON AND EVENING AS THE FRIGID ARCTIC AIRMASS BEGINS TO
POUR INTO THE AREA. SKIES WILL CLEAR OUT OVERNIGHT WITH LOWS RANGING
FROM MIDDLE TEENS IN THE NW PIEDMONT TO LOWER/MID 20S SE.
LONG TERM /MONDAY THROUGH FRIDAY/
AS OF 300 AM SATURDAY...
ON MONDAY MORNING, STRONG HIGH PRESSURE WILL BE CENTERED OVER
MONTANA AND EXTEND SOUTHEAST ALL THE WAY INTO FLORIDA. MONDAY WILL
BE A SUNNY BUT SHARPLY COLDER DAY. HIGHS ON MONDAY WILL BE ANYWHERE
BETWEEN 20 AND 25 DEGREES COLDER THAN SUNDAY AND WILL ONLY REACH THE
MID 20S TO THE UPPER 30S. CLOUDS WILL BEGIN TO INCREASE MONDAY
NIGHT, AND SLIGHTLY GREATER CLOUD COVER IS THE PRIMARY REASON THAT
MONDAY NIGHT'S LOWS HAVE COME UP EVER SO SLIGHTLY FROM THE PREVIOUS
FORECAST - WHILE TEENS ARE STILL FORECAST, SINGLE DIGIT LOWS HAVE
BEEN REMOVED FROM THE FORECAST.
FOCUS THEN SHIFTS TO THE STORM THAT WILL DEVELOP IN THE GULF OF
MEXICO TUESDAY, CROSS FLORIDA, AND MOVE UP THE ATLANTIC SHORELINE
TUESDAY NIGHT INTO WEDNESDAY. OVER THE LAST SEVERAL DAYS, THE
EUROPEAN ENSEMBLE HAS CONSISTENTLY BEEN THE FARTHEST NORTHWEST
(INLAND) WITH PRECIPITATION, AND WHILE THAT REMAINS THE CASE, THE
DETERMINISTIC EUROPEAN, GFS, AND GEFS HAVE ALL SHIFTED PRECIPITATION
FARTHER TO THE NORTHWEST NOW AS WELL. THERE IS RATHER GOOD AGREEMENT
NOW THAT TUESDAY NIGHT WILL BE THE PERIOD WITH THE GREATEST
PRECIPITATION, AND CONSIDERING THE COLD TEMPERATURES THAT WILL BE IN
PLACE, THE PRECIPITATION WOULD BE ALL SNOW. HAVE BUMPED UP POPS TO
LIKELY TUESDAY EVENING GENERALLY ALONG AND EAST OF THE US-1
CORRIDOR, BUT WE DO NOT PRODUCE SNOWFALL ACCUMULATION FORECASTS THAT
FAR OUT. SOME SNOW COULD LINGER WEDNESDAY MORNING, BUT CONDITIONS
SHOULD BE DRY BY WEDNESDAY AFTERNOON. TEMPERATURES TUESDAY, TUESDAY
NIGHT, AND WEDNESDAY SHOULD BE SIMILAR TO THE MONDAY AND MONDAY
NIGHT PERIOD, WITH HIGHS RANGING FROM THE MID 20S TO THE MID 30S AND
LOWS IN THE TEENS.
AS LOW PRESSURE MOVES OVER THE ATLANTIC OCEAN, THERE SHOULD BE A
BRIEF RESPITE FROM PRECIPITATION AS HIGH PRESSURE BECOMES CENTERED
OVER THE MID-ATLANTIC STATES BY THURSDAY MORNING. THE ECMWF AND GFS
BOTH SHOW YET ANOTHER SYSTEM DEVELOPING OFF THE SOUTHEASTERN COAST,
AND VARY IN TIMING AND HOW FAR INLAND PRECIPITATION WILL SPREAD. THE
GFS IS QUICKER AND GIVES MORE OF A GLANCING BLOW TO THE EASTERN HALF
OF THE STATE THURSDAY AND THURSDAY NIGHT, WHILE THE ECMWF IS SLOWER
(THURSDAY NIGHT AND FRIDAY) AND IS MUCH FARTHER INLAND WITH ITS
PRECIPITATION. WHILE THERE WILL BE SOME MODERATING OF TEMPERATURES
FROM THE FIRST HALF OF THE WEEK, THE HIGH TO THE NORTH WILL STILL
HAVE COLD AIR IN PLACE BEFORE THE PRECIPITATION AND ALLOW FOR
ANOTHER ROUND OF SNOW MIXING WITH RAIN. WON'T GET TOO CUTE WITH
DETAILS FOR NOW, BUT DO HAVE CHANCE POPS APPROXIMATELY EAST OF US-1.
HIGHS WILL BE IN THE 30S ON THURSDAY AND IN THE 40S ON FRIDAY, WITH
LOWS IN THE MID TEENS TO MID 20S THURSDAY NIGHT.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
AS OF 1245 PM SATURDAY...
A BAND OF LIGHT RAIN IS BEGINNING TO EXIT THE COASTAL PLAIN AS OF
1745Z. FORECAST GUIDANCE CONTINUES TO HIGHLIGHT A LULL IN
PRECIPITATION THIS EVENING, BUT AN AREA OF MVFR CIGS OVER THE
WESTERN PIEDMONT IS EXPECTED TO SPREAD EASTWARD AND LOWER AHEAD OF
THE NEXT ROUND OF RAIN. CONFIDENCE IS HIGH ON CIGS LOWERING TO IFR
TO LIFR, BUT MEDIUM-LOW ON WHEN THIS LOWERING WILL TAKE PLACE. AREAS
OF FOG, POTENTIALLY DENSE, WILL ALSO BE POSSIBLE AS CIGS LOWER TO
LESS THAN 500 FEET AND NORTH OF A WARM FRONT LIFTING INTO CENTRAL
NC. THE NEXT AREA OF RAIN WILL LIFT NORTH FROM SC LATE TONIGHT INTO
EARLY SUN MORNING WITH SCATTERED SHOWERS POSSIBLE ON ITS NORTHERN
PERIPHERY (SHOWERS MOST PROBABLE AT GSO, INT, AND RWI, WHILE STEADY
RAIN MOST PROBABLE AT FAY AND RWI). REACHING AIRPORT LANDING MINIMUM
THRESHOLDS WILL BE POSSIBLE AT ANY TAF SITE, BUT HIGHEST PROBABILITY
AT INT, GSO, AND POSSIBLY FAY.
OUTLOOK: WIDESPREAD IFR TO LIFR RESTRICTIONS WILL LINGER THROUGH
MIDDAY SUNDAY AS A COLD FRONT AND ASSOCIATED SCATTERED RAIN SHOWERS
MOVE THROUGH THE AREA. CONDITIONS WILL IMPROVE AND EVENTUALLY RETURN
TO VFR FROM SW TO NE DURING THE AFTERNOON AND EVENING. ADDITIONALLY,
PRECIP COULD END AS A BRIEF CHANGEOVER TO SNOW ACROSS THE NORTHERN
TAF SITES LATE SUNDAY AFTERNOON AND EVENING.
VFR CONDITIONS ARE EXPECTED MONDAY AND TUESDAY. FORECAST
UNCERTAINTY IS HIGH, HOWEVER A POTENTIAL WINTER STORM SYSTEM COULD
BRING SUB-VFR RESTRICTIONS IN THE FORM OF SNOW TUESDAY AFTERNOON
THROUGH EARLY WEDNESDAY.
CLIMATE
RECORD LOW MAXIMUM TEMPERATURES:
JANUARY 20:
KGSO: 29/1983
KRDU: 28/1970
JANUARY 21:
KFAY: 31/1983
JANUARY 22:
KGSO: 29/2014
KRDU: 27/1970
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...SWIGGETT/CBL
NEAR TERM...SWIGGETT
SHORT TERM...CBL
LONG TERM...GREEN
AVIATION...SWIGGETT/CBL
CLIMATE...RAH
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page