306
FXUS62 KRAH 170828
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
328 AM EST SAT JAN 17 2026
WHAT HAS CHANGED
AS OF 320 AM SATURDAY...
* FORECAST LIQUID EQUIVALENT PRECIPITATION AMOUNTS FOR TONIGHT
AND SUNDAY HAVE INCREASED.
* LOCATIONS IN WHICH A COATING OF SNOW IS EXPECTED HAVE BEEN
REDUCED AND ARE FOCUSED ACROSS THE NORTHERN PIEDMONT.
* THE PROBABILITIES AND RISK OF A HIGHER END/WORST CASE EVENT
WITH SNOW TOTALS OF 1 OR 2 INCHES HAVE DECREASED GREATLY.
KEY MESSAGES
AS OF 320 AM SATURDAY...
1) A DECAYING BAND OF PRECIPITATION MOVING FROM THE NC MOUNTAINS
INTO THE FOOTHILLS AND WESTERN PIEDMONT COULD BRING SOME SPOTTY
LIGHT RAIN AND A FEW SLEET PELLETS TO THE TRIAD AROUND DAYBREAK
THIS MORNING.
2) A STRONG UPPER-LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION
LATE TONIGHT AND SUNDAY PRODUCING A SHIELD OF PRECIPITATION
ACROSS CENTRAL NC. THE RAIN WILL MIX WITH SNOW AT TIMES, MAINLY
ACROSS NORTHERN AREAS, AND THEN CHANGE TO ALL SNOW BEFORE ENDING
FROM WEST TO EAST DURING THE AFTERNOON. A SLUSHY COATING OF
SNOW IS POSSIBLE, MAINLY ON ELEVATED SURFACE WITH THE GREATEST
CHANCE ACROSS THE NORTHERN AND NORTHWESTERN PIEDMONT.
3) A MODIFIED, ARCTIC COLD AIR MASS IS EXPECTED EARLY-MID NEXT
WEEK, WITH TEMPERATURES IN THE TEENS AND 10 TO 15 DEGREES BELOW
NORMAL FOR CONSECUTIVE MORNINGS.
DISCUSSION
AS OF 320 AM SATURDAY...
KEY MESSAGE 1... A DECAYING BAND OF PRECIPITATION MOVING FROM
THE NC MOUNTAINS INTO THE FOOTHILLS AND WESTERN PIEDMONT COULD
BRING SOME SPOTTY LIGHT RAIN AND A FEW SLEET PELLETS TO THE
TRIAD AROUND DAYBREAK THIS MORNING.
THE PRECIPITATION BAND ACROSS THE NC MOUNTAINS IS EXPECTED TO
CONTINUE TO WEAKEN AND DIMINISH AS IT MOVES INTO THE WESTERN
PIEDMONT AND TRIAD AREA AROUND DAYBREAK. ANY PRECIPITATION THAT
FALLS IN THE TRIAD WILL BE LIGHT AND SHORT LIVED. WITH A DRY
AIRMASS IN PLACE, A FEW SLEET PELLETS MAY BE OBSERVED BUT NO
ACCUMULATION IS EXPECTED. TEMPERATURES IN THE TRIAD WILL RANGE
NEAR OR JUST ABOVE FREEZING EARLY THIS MORNING AND WARM INTO THE
MID 30S BY MID MORNING. DRY CONDITIONS ARE EXPECTED THIS MORNING
ACROSS THE REMAINDER OF CENTRAL NC.
KEY MESSAGE 2...A STRONG UPPER-LEVEL DISTURBANCE WILL MOVE
ACROSS THE REGION LATE TONIGHT AND SUNDAY PRODUCING A SHIELD OF
PRECIPITATION ACROSS CENTRAL NC. THE RAIN WILL MIX WITH SNOW AT
TIMES, MAINLY ACROSS NORTHERN AREAS, AND THEN CHANGE TO ALL SNOW
BEFORE ENDING FROM WEST TO EAST DURING THE AFTERNOON. A SLUSHY
COATING OF SNOW IS POSSIBLE, MAINLY ON ELEVATED SURFACE WITH THE
GREATEST CHANCE ACROSS THE NORTHERN AND NORTHWESTERN PIEDMONT.
A 100+ KT JET AT 500 MB ACROSS MONTANA AND WYOMING EARLY THIS
MORNING WILL DIVE SOUTH AND AID IN CARVING OUT A VIGOROUS UPPER-
LEVEL TROUGH EXTENDING FROM THE WESTERN OH VALLEY INTO THE LOWER MS
VALLEY LATE TONIGHT. THE TROUGH WILL ADVANCE EAST ACROSS THE
SOUTHERN APPALACHIANS AROUND MIDDAY SUNDAY AND THEN BECOME NEGATIVELY
TILTED AS IT REACHES THE SOUTHEAST COAST BY SUNDAY EVENING. A STRONG
SOUTHWESTERLY JET AT 250 MB WILL DEVELOP ACROSS THE EASTERN U.S.
WITH A 175+ KT JET CORE DEVELOPING ACROSS THE MID ATLANTIC EARLY
SUNDAY MORNING. MOISTURE WILL STREAM NORTH ALONG THE SOUTHEAST COAST
ON SUNDAY WITH PW VALUES EXCEEDING 135% OF NORMAL. GLOBAL AND
MESOSCALE MODELS DEPICT THIS SCENARIO BUT DIFFERENCES IN THE TROUGH
CONFIGURATION AND THE AVAILABILITY OF COLD AIR ARE DRIVING CRITICAL
DIFFERENCES IN THE POTENTIAL FOR ACCUMULATING SNOW.
WE EXPECT PATCHES OF LIGHT RAIN TO DEVELOP ACROSS THE PIEDMONT OF
GA/SC/NC DURING THE LATE EVENING AND GROW INTO A SOUTHWEST TO
NORTHEAST ORIENTED PRECIPITATION SHIELD AFTER MIDNIGHT AND TOWARD
DAYBREAK. GIVEN THE JET CONFIGURATION, A SHARP CUT-OFF TO THE
PRECIPITATION SHIELD WITH LITTLE TO NOW PRECIPITATION OBSERVED TO
THE WEST IS EXPECTED WITH THIS LINE STRETCHING FROM CHARLOTTE
NORTHEAST TO THE TRIAD. THE PRECIPITATION SHIELD WILL TRANSLATE
EASTWARD ON SUNDAY WITH PRECIP ENDING IN THE TRIAD AROUND MIDDAY,
ENDING IN THE TRIANGLE TOWARD MID AFTERNOON AND THE COASTAL PLAIN
TOWARD LATE AFTERNOON. ALL OF THE PRECIPITATION SHOULD HAVE EXITED
BY DINNER TIME.
LIQUID EQUIVALENT PRECIPITATION AMOUNTS HAVE GENERALLY TRENDED UP
DURING THE RECENT CYCLES AND WITH MORE MESOSCALE MODELS CAPTURING
THE EVENT, A FEW OUTLIERS ARE SHOWING SOME NOTABLY HIGHER AMOUNTS.
WPC GUIDANCE AND ENSEMBLES OF VARIOUS MODELING SYSTEMS GENERALLY
PROVIDE A CONSENSUS 0.05-0.10 INCHES IN THE TRIAD, 0.2 TO 0.3 INCHES
ACROSS THE REST OF THE PIEDMONT INCLUDING THE TRIANGLE, AND 0.3 TO
0.5 ACROSS THE COASTAL PLAIN AND SANDHILLS.
MOST OF THE GUIDANCE NOTES THAT THE MID AND UPPER LEVELS ARE
SUFFICIENTLY SATURATED AND COLD ENOUGH TO BECOME GLACIATED AND
GENERATE SNOW ALOFT. A KEY DIFFERENCE LIES IN HOW WARM THE BOUNDARY
LAYER TEMPERATURES WILL BE. SO IT WILL BE SNOWING ACROSS MUCH OF THE
AREA JUST A FEW THOUSAND FEET ABOVE THE SURFACE BUT THE MILD
BOUNDARY LAYER WILL MELT MUCH OF THE SNOW. AS NOTED IN PREVIOUS
DISCUSSIONS, THE COLD AIR HIGH IS NOT IN A FAVORED LOCATION WHICH
RAISES DOUBTS ABOUT THE AVAILABILITY OF SUFFICIENTLY COLD AND DRY
LOW-LEVEL AIR FOR SNOW. ANOTHER CONCERN IS HOW WARM IT WILL GET
TODAY WITH CLOUD COVER AND A SOUTHERLY WIND THIS EVENING KEEP
TEMPERATURES MILD, ANOTHER INAUSPICIOUS ELEMENT AHEAD OF ANY
POTENTIAL SNOW EVENT.
FOR THE SNOW LOVERS, THE NAM PROVIDES SOME HOPE AS IT HOLDS ONTO THE
STABLE COLD AIRMASS ACROSS THE WESTERN AND NORTHERN PIEDMONT AND
PROVIDES TEMPERATURES IN THE MID 30S AHEAD OF THE ARRIVAL OF
PRECIPITATION. IN ADDITION, IT IS VERY GENEROUS WITH THE
PRECIPITATION AMOUNTS, NEARLY DOUBLE THE CONSENSUS AMOUNTS NOTED
ABOVE, WHICH PROVIDES ENOUGH DIABATIC COOLING FROM MELTING SNOW TO
GET TEMPS DOWN TO 33 AND ALLOW FOR MORE GENEROUS ACCUMULATIONS.
THE MOST LIKELY SCENARIO WITH THIS EVENT IS FOR PATCHY LIGHT RAIN TO
DEVELOP ACROSS SOUTHERN NC LATE SATURDAY EVENING AND THEN EXPAND
NORTHEAST OVERNIGHT WITH A SHARP EDGE/CUT OFF TO THE WEST.
TEMPERATURES WILL LIKELY BE IN THE UPPER 30S AND LOWER 40S AS THE
PRECIPITATION STARTS AND THEN SLOWLY COOL AS COLDER AIR FILTERS IN
FROM THE NORTHWEST AND DIABATIC COOLING FROM MELTING SNOW COOLS THE
BOUNDARY LAYER. WITH TEMPERATURES STARTING OFF COLDER IN THE TRIAD,
THE RAIN WILL MIX WITH WET SNOW TOWARD DAYBREAK. DURING THE EARLY
AND MID MORNING, MIXED RAIN AND SNOW WILL BE FALLING ACROSS THE
TRIAD WITH MORE WIDESPREAD RAIN TO THE EAST WHICH COULD MIX WITH A
LITTLE WET SNOW NEAR THE VA BORDER AND I-85 REGION. SURFACE
TEMPERATURES WILL GRADUALLY COOL AS COLDER AIR FILTERS IN FROM THE
NORTHWEST AS WELL AS DIABATIC COOLING FROM MELTING SNOW. THE MIXED
RAIN AND SNOW IN THE TRIAD WILL LIKELY END AS A BRIEF PERIOD OF WET
SNOW DURING THE LATE MORNING AND MIDDAY HOURS. THE TRANSITION TO
MIXED RAIN AND SNOW AND EVENTUALLY MOSTLY SNOW WILL SHIFT EAST
REACHING THE TRIANGLE AND VA BORDER COUNTIES DURING THE EARLY TO MID
AFTERNOON. STILL THINK IT IS DOUBTFUL THAT MUCH IF ANY SNOW WILL BE
OBSERVED IN THE SANDHILLS.
WHILE MUCH OF THE PIEDMONT AND VA BORDER COUNTIES SHOULD OBSERVE
SOME MIXED RAIN AND SNOW OR EVEN A CHANGE OVER TO MOSTLY SNOW FOR A
TIME, SURFACE TEMPERATURES JUST ABOVE FREEZING AND A DAYTIME EVENT
SHOULD LIMIT THE ACCUMULATION EFFICIENCY. BUT A COATING OF SNOW,
MAINLY ON ELEVATED AND GRASSY LOCATIONS SEEMS POSSIBLE/REASONABLE
NORTH OF U.S. ROUTE 64 WITH A FEW SPOTS HITTING JACK POT AMOUNTS OF
A HALF INCH ALONG THE VA BORDER AND EXTENDING INTO THE I-85 CORRIDOR
EAST OF THE TRIAD.
ALL OF THE PRECIPITATION SHOULD WRAP UP BY EARLY SUNDAY EVENING.
TEMPERATURES SHOULD FALL BELOW FREEZING BY DINNER TIME SUNDAY AND
THEN CRASH INTO THE LOWER 20S WHICH MAY RESULT IN SOME REFREEZING
AND ICY PATCHES ON ROADWAYS SUNDAY NIGHT. -BLAES
KEY MESSAGE 3...A MODIFIED, ARCTIC COLD AIR MASS IS EXPECTED EARLY-MID NEXT
WEEK, WITH TEMPERATURES IN THE TEENS AND 10 TO 15 DEGREES BELOW
NORMAL FOR CONSECUTIVE MORNINGS.
DOWNSTREAM OF A HIGHLY AMPLIFIED RIDGE OVER THE ERN PACIFIC AND AK,
THE LATTER WHERE 500 MB STANDARDIZED HEIGHT ANOMALIES OF 3-4 SIGMA
ARE FORECAST, A PERSISTENT POLAR VORTEX OVER HUDSON BAY WILL ANCHOR
A BROAD TROUGH OVER THE REST OF CNTL AND ERN NOAM. A SERIES OF
SHORTWAVE PERTURBATIONS WILL NAVIGATE THE ASSOCIATED CYCLONIC FLOW
AND AMPLIFY MOST SHARPLY FROM THE NORTHWEST TERRITORIES TO THE
MIDDLE ATLANTIC THROUGH TUE, WITH RELAXATION OF THE TROUGH AND
INCREASING INTERACTION FROM THE SRN STREAM MID-LATE WEEK.
AT THE SURFACE, A CLIPPER TYPE LOW, ONE RELATED TO ONE OF THE
AFOREMENTIONED SHORTWAVE PERTURBATIONS IN HIGHLY AMPLIFIED, NWLY
FLOW ALOFT, WILL SWEEP AN ARCTIC COLD FRONT ACROSS CNTL NC MON
NIGHT. A FOLLOWING ARCTIC HIGH, INITIALLY ~1045 MB OVER THE
NORTHWEST TERRITORIES, WILL WEAKEN ABOUT 10 MB AS IT SETTLES ACROSS
THE MIDDLE ATLANTIC THROUGH MID-WEEK. MODIFICATION OF THE ASSOCIATED
AIRMASS WILL OCCUR MOST MARKEDLY AS IT PROGRESSES BEYOND SNOW COVER
SURROUNDING THE GREAT LAKES, FROM THE NRN PLAINS AND UPR MS VALLEY
TO THE INTERIOR MIDDLE ATLANTIC AND NORTHEAST. THE RESULT FOR CNTL
NC WILL BE AN UNSEASONABLY COLD TUE, WITH HIGHS ABOUT 15 F BELOW
AVERAGE AND MOSTLY IN THE 30S (TO AROUND 40 ACROSS SRN COUNTIES),
FLANKED BY A PAIR OF MORNINGS WITH TEMPERATURES MOSTLY IN THE
TEENS.
AVIATION /08Z SATURDAY THROUGH WEDNESDAY/
AS OF 145 AM SATURDAY...
MOISTURE TRANSPORT AND LIFT, FOCUSED ALONG THE AXIS OF A STRONG LOW-
LEVEL JET, WILL RESULT IN A GOOD CHANCE OF MVFR CEILINGS OVER THE NC
PIEDMONT LATER THIS MORNING, ESPECIALLY AT INT/GSO. VERY LIGHT RAIN,
WITH MINIMAL TO NO VISIBILITY RESTRICTIONS, WILL ALSO PROBABLY
ACCOMPANY THE MVFR CLOUD BAND. OTHERWISE, THE AFOREMENTIONED LOW-
LEVEL JET WILL FAVOR LOW-LEVEL WIND SHEAR AND/OR MECHANICAL
TURBULENCE UNTIL SURFACE WINDS STRENGTHEN, AND THE NOCTURNAL
TEMPERATURE INVERSION BREAKS, WITH DAYTIME HEATING BETWEEN 14-16Z.
SSWLY WINDS MAY THEN GUST INTO THE LOW-MID 20S KTS AT TIMES THROUGH
THE AFTERNOON, THEN SUBSTANTIALLY LESSEN/DIMINISH AROUND SUNSET.
OUTLOOK: A PRECIPITATION BAND, AND ASSOCIATED FLIGHT RESTRICTIONS,
WILL LIKELY BLOSSOM ALONG AND EQUATORWARD OF AN INTENSE UPR-LEVEL
JET STREAK OVER THE SOUTHEAST TONIGHT, INCLUDING OVER CNTL NC. THE
PRECIPITATION BAND WILL THEN GRADUALLY EDGE AND PIVOT EWD AND OUT OF
CNTL NC THROUGH SUN-AFTERNOON-EVENING. WHILE A COLD RAIN WILL BE THE
PREDOMINANT PRECIPITATION TYPE, A MIXING WITH OR CHANGEOVER TO SNOW
AT TIMES WILL BE POSSIBLE WITHIN HEAVIER INTENSITY PORTIONS OF THE
BAND ON SUNDAY, MOST LIKELY AT RDU, AND NEAR AND EAST OF GSO.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...BLAES/MWS
AVIATION...MWS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page