533
FXUS62 KRAH 200520
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1220 AM EST THU FEB 20 2025
SYNOPSIS
LOW PRESSURE WILL TRACK NORTHEASTWARD JUST OFF THE CAROLINA COAST
THROUGH TONIGHT, THEN AN UPPER LEVEL DISTURBANCE WILL CROSS THE
REGION THURSDAY MORNING. OTHERWISE, ARCTIC HIGH PRESSURE OVER THE
CENTRAL PORTION OF THE UNITED STATES WILL GRADUALLY WEAKEN AS IT
DRIFTS EAST THEN SOUTHEAST OVER THE MISSISSIPPI RIVER VALLEY AND
INTO THE SOUTHEAST TONIGHT THROUGH SATURDAY.
NEAR TERM /THROUGH THURSDAY/
AS OF 905 PM WEDNESDAY...
* WINTER STORM WARNINGS AND ADVISORIES REMAIN IN EFFECT UNTIL 1 PM
THURSDAY.
MINIMAL CHANGES ARE NEEDED TO THE FORECAST TRENDS FOR THE REMAINDER
OF THE NIGHT. THE BACK EDGE OF THE HEAVIER PRECIP (MOSTLY SNOW WITH
A LITTLE SLEET EXCEPT PARTLY OR MOSTLY FREEZING RAIN IN THE FAR SE)
HAS PUSHED INTO THE COASTAL PLAIN, WITH LIGHTER AND MORE SPORADIC
PRECIP ALONG THE HWY 1 CORRIDOR, WHERE CURRENT GOES LAYER WV IMAGERY
SHOWS CONSIDERABLE DRYING WITHIN THE MIXED PHASE REGION ALOFT,
CAUSING A LOSS OF ICE IN THE CLOUDS AND A TRANSITION TO FREEZING
DRIZZLE OR SNOW GRAINS, AND VERY LITTLE TO NO PRECIP OVER THE FAR W
PIEDMONT WHERE THE DRIER AIR ALOFT IS DEEPER. THE CURRENT FORECAST
MATCHES WELL WITH THE OBSERVED P-TYPES AND THE PACE OF PRECIP EXIT.
ACCUMULATION STILL ONGOING IN THE E (ALBEIT MUCH LESS THAN EARLIER
RATES), WHILE WESTERN SECTIONS ARE STILL EXPECTED TO SEE THE ARRIVAL
OF A BATCH OF LIGHT SNOW TOWARD MORNING WITH THE INCOMING STRONG
DPVA. AS SUCH, WILL KEEP THE WARNING AND ADVISORY IN PLACE. ADJUSTED
LOWS TONIGHT DOWN SLIGHTLY TO MATCH THE TEMP TRENDS, TO THE UPPER
TEENS TO MID 20S. -GIH
EARLIER DISCUSSION FROM 300 PM: REGIONAL RADAR IMAGERY SHOWS THE
WELL ADVERTISED MIXED P-TYPE WINTRY EVENT IS WELL UNDERWAY WITH
WIDESPREAD PRECIPITATION ACROSS CENTRAL NC. KRAX DUAL POLARIZATION
DATA SHOWS THE FROZEN/LIQUID LINE STRETCHING FROM THE SOUTHERN
SANDHILLS, THROUGH HARNETT COUNTY, INTO SOUTHERN JOHNSTON, AND
NORTHERN WAYNE COUNTY. PRECIPITATION ACROSS THE AREA IS EXPECTED TO
INCREASE IN INTENSITY AS A BETTER OVERLAP OF WAA AND ISENTROPIC
ASCENT DEVELOPS OVER THE AREA THROUGH 8 TO 10 PM.
FREEZING RAIN: SOUTH OF THIS DELINEATING LINE, SPC MESOANALYSIS DATA
SHOWS THE WETBULB FREEZING LINE JUST SOUTH OF OUR AREA AND WILL
LIKELY RESULT IN A SWATH OF ACCUMULATING FREEZING RAIN. DIURNAL
TIMING IS NOT PARTICULARLY FAVORABLE FOR EFFICIENT ICE ACCRUAL, BUT
ICE IS EXPECTED TO BE MARGINALLY SUFFICIENT ESPECIALLY ON ELEVATED
SURFACES THROUGH THIS AFTERNOON. ICE ACCRUAL WILL BECOME MORE
EFFICIENT AFTER SUNSET AND THROUGH ROUGHLY 8 PM TO 10 PM ACROSS THIS
AREA AND RESULT IN ADDITIONAL ACCUMULATIONS OF A TENTH TO UP TO A
THIRD OF AN INCH, HIGHEST IN WAYNE AND SAMPSON COUNTIES. OVERALL
PRECIPITATION RATES WILL BEGIN TO LESSEN AFTER 8 PM, BUT POINT
SOUNDINGS STILL SHOW A RELATIVELY DEEP SATURATED LAYER AND INFERRED
WAA THROUGHOUT, SO LINGERING LIGHT DRIZZLE AND/OR FREEZING DRIZZLE
WILL BE POSSIBLE.
SNOW AND SLEET: ACCOMPANYING THE INCREASED WAA WILL BE WARMING
TEMPERATURES ALOFT AND RESULT IN A SWATH OF MOSTLY SLEET WINTRY MIX
DEVELOPING ACROSS CENTRAL NC FROM CHARLOTTE, THROUGH THE TRIANGLE
AND INTO THE NORTHERN COASTAL PLAIN, MAINLY NORTH OF THE SNOW/LIQUID
LINE DESCRIBED ABOVE. A SIGNIFICANT AMOUNT OF SLEET WILL BE POSSIBLE
WITHIN THIS AREA AND WAS A LARGE CONTRIBUTOR TO THE UPGRADE TO A
WINTER STORM WARNING FOR RALEIGH AND WAYNE COUNTIES EARLIER THIS
MORNING. WE COULD SEE SLEET ACCUMULATIONS OF A COUPLE TENTHS TO
UPWARDS OF OVER 0.5". ADDITIONALLY, WPC SNOWBAND PROBABILITY TOOL
SHOWS THE POTENTIAL FOR A BAND OF EFFICIENT SNOW/SLEET RATES THAT
MAY LEAD TO A NARROW CORRIDOR OF ENHANCED TOTALS AND LOCALIZED
GREATER IMPACTS. ADDITIONAL SNOW/SLEET ACCUMULATIONS 1 TO 4 INCHES
ARE EXPECTED, MAINLY FROM RALEIGH NORTH AND EAST INTO NORTHEASTERN
NC.
THE MAIN SHIELD OF WINTRY PRECIPITATION WILL BEGIN TO SHIFT EASTWARD
LATE TONIGHT WITH AN OVERALL LULL IN MEASURABLE PRECIPITATION WITH
LINGERING DRIZZLE/FREEZING-DRIZZLE POSSIBLE INTO EARLY THURS
MORNING. SOME TRIMMING OF THE WINTER WEATHER WARNINGS/ADVISORIES MAY
BE ABLE TO BE DONE OVERNIGHT TO BETTER CAPTURE THE THREAT INTO THURS
MORNING. AN APPROACHING STRONG UPPER TROUGH AND STEEPENING LAPSE
RATES WILL RESULT IN THE REDEVELOPMENT OF SNOW SHOWERS THURS MORNING
WITH GREATEST CHANCES TOWARDS THE NORTHWEST PIEDMONT INTO THE
TRIANGLE AND TOWARDS THE NC/VA BORDER. OVERALL SNOW ACCUMULATIONS
WILL BE MINOR, BUT A VERY COLD GROUND, DEEP SATURATION IN THE DGZ,
AND HIGH SNOW RATIOS CAN RESULT IN EFFICIENT AND QUICK ACCUMULATIONS
UP TO AN INCH IN SPOTS, BUT MOSTLY A DUSTING IS EXPECTED. AS THIS
AREA MOVES EAST AND DOWNSLOPING DRYING TAKES OVER BEHIND A COLD
FRONT, STRONG WIND GUSTS OF 20 TO 30 MPH WITH INFREQUENT GUSTS UP TO
35 MPH POSSIBLE. SOME GUSTINESS MAY CONTINUE OVERNIGHT DUE TO
CONTINUED CAA, BUT MAY BE MORE INFREQUENT AND LOWER THAN DURING THE
AFTERNOON/EVENING. LOWS TONIGHT WILL SETTLE IN THE 20S WITH HIGHS ON
THURS IN THE 30S. INCREASING SUNSHINE THROUGH THE AFTERNOON WILL
HELP TO MELT SOME SNOW/ICE BEFORE SUNSET.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/
AS OF 150 PM WEDNESDAY...
* VERY COLD CONDITIONS THURSDAY AND FRIDAY NIGHTS WITH LOWS 10 TO 20
DEGREES BELOW AVERAGE.
* LOWEST WIND CHILL VALUES ON FRIDAY MORNING WILL RANGE BETWEEN 6
AND 12 DEGREES.
ALOFT, THE LOW ALONG THE NRN MID-ATLANTIC COAST THU EVE WILL MOVE
ENEWD OUT OVER THE NRN ATLANTIC THU NIGHT/FRI, WHILE THE TROUGH
GRADUALLY SHIFTS EWD OUT OF THE REGION. WNWLY FLOW WILL PREVAIL OVER
THE AREA THROUGH FRI NIGHT. AT THE SURFACE, ARCTIC HIGH PRESSURE
WILL RIDGE INTO CENTRAL NC AS IT DRIFTS SLOWLY EWD ACROSS THE
MIDWEST THU NIGHT/FRI. THE HIGH MAY SPLIT IN TWO FRI NIGHT, WITH
ONCE CENTER LINGERING OVER THE MIDWEST AND THE OTHER MOVING EWD INTO
THE MID-ATLANTIC FRI NIGHT. THE WEATHER SHOULD REMAIN DRY THROUGH
FRI NIGHT. HIGHS ON FRIDAY STILL EXPECTED TO BE INFLUENCED BY ANY
LINGERING SNOW/ICE ON THE GROUND, ESPECIALLY IN THE EAST AND
NORTHEAST PORTIONS OF CENTRAL NC WHERE HIGHS IN THE UPPER 30S ARE
EXPECTED. ELSEWHERE STILL EXPECT HIGHS IN THE LOW/MID 40S FRI.
THU NIGHT: SKIES SHOULD BE CLEAR, HOWEVER WINDS WILL GENERALLY BE IN
THE 3-8 KT RANGE THROUGH THE NIGHT. LOW-LEVEL THICKNESSES IN THE
1255-1265M RANGE ARE EXPECTED. THE CONTINUED STIRRING MAY SLIGHTLY
LIMIT RADIATIONAL COOLING, BUT WITH THE FORECAST THICKNESSES AND
CLEAR SKIES EXPECT LOWS TO DROP INTO THE MID/UPPER TEENS ACROSS
CENTRAL NC. HOWEVER, THE WINDS WILL RESULT IN WIND CHILL VALUES OF
GENERALLY 6-12 DEGREES.
FRI NIGHT: THE LOW-LEVEL THICKNESSES SHOULD INCREASE INTO THE 1280M-
1290M RANGE, HOWEVER WITH THE HIGH NOW OVERHEAD, WINDS SHOULD BE
CALM. THE QUESTION FOR FRI NIGHT WILL BE IF/HOW EXPANSIVE SOME CLOUD
COVER MAY BE, WHICH WOULD IMPACT HOW MUCH RADIATIONAL COOLING WILL
OCCUR. FOR NOW, EXPECT LOWS GENERALLY IN THE MID TEENS TO LOW 20S.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
AS OF 1220 AM THURSDAY...
LARGELY DRY WEATHER IS EXPECTED, WITH A GRADUAL WARMING TREND AS THE
INCOMING ARCTIC HIGH SLOWLY MODIFIES, WEAKENS, AND SHIFTS TO OUR S.
BROAD MID LEVEL TROUGHING WILL PERSIST ACROSS CENTRAL AND WESTERN
NOAM, AS A SERIES OF SHORTWAVE TROUGHS PASSES THROUGH OUR REGION,
BRINGING BOUTS OF CLOUDS. THE FIRST OF THESE, A PERTURBATION NOW
OVER THE PACNW, WILL DIVE THROUGH THE CENTRAL PLAINS AND CROSS THE
CAROLINAS SAT AFTERNOON/EVENING. THIS SHOULD BRING A SHOT OF HIGH
AND MID CLOUDS, BUT LITTLE ELSE, GIVEN THE LACK OF OPPORTUNITY TO
DRAW IN ANY LOWER LEVEL MOISTURE. THE SECOND PERTURBATION WILL MOVE
FROM THE DESERT SOUTHWEST FRI NIGHT AND CROSS OUR REGION LATE SUN
NIGHT INTO MON MORNING, POTENTIALLY PHASING WITH A NORTHERN STREAM
WAVE. SOME DETERMINISTIC MODELS LIKE THE NAM/GFS DEVELOP A COASTAL
LOW OFF THE SOUTHEAST AND SHOW IT DEEPENING IT AS IT HEADS NE JUST
OFF THE CAROLINA COAST. THE NBM SHOWS A NON-ZERO BUT VERY LOW (UNDER
20%) CHANCE OF PRECIP OVER OUR FAR E, CLOSE TO THE GEFS AND ENS
MEAN, WHILE THE GEPS IS ENTIRELY DRY. WILL KEEP THE FORECAST DRY BUT
SHOW A SHOT OF THICK MID-LEVEL CLOUDS ACCOMPANYING THIS FEATURE LATE
SUN NIGHT INTO EARLY MON. LASTLY, THE NBM/LREF AND DETERMINISTIC
MODELS TAKE A THIRD SHORTWAVE THROUGH THE MID ATLANTIC REGION,
EITHER CROSSING NC OR PASSING JUST TO OUR N, AND WHILE THE PWS WILL
BE CREEPING UP, THE EXPECTED SURFACE RIDGE ALONG THE GULF COAST WILL
GREATLY LIMIT ANY INFLUX OF LOW LEVEL MOISTURE INTO CENTRAL NC. WILL
MAINTAIN A DRY FORECAST, BUT AGAIN WITH AN UPTICK IN CLOUDS TUE.
THIS LAST WAVE WIL DRAG A WEAK SURFACE COLD FRONT THROUGH THE AREA,
BUT THE WEAK SURFACE RIDGE MOVING IN BEHIND IT IS ONLY SLIGHTLY
COOLER. OVERALL, MUCH BELOW NORMAL TEMPS SAT WILL WARM TO NEAR
NORMAL BY MON, AND BE 1-2 CATEGORIES ABOVE NORMAL TUE/WED, WITH
HIGHS IN THE 60S. -GIH
AVIATION /00Z THURSDAY THROUGH MONDAY/
AS OF 644 PM WEDNESDAY...
THE BACK EDGE OF THE SNOW HAS LARGELY PUSHED EAST OF THE TRIAD
TERMINALS (GSO/INT), WITH PREVAILING MVFR CEILINGS BEHIND IT. THERE
IS THE POTENTIAL SOME OFF AND ON LIGHT SNOW MAY STILL BE AROUND TILL
ABOUT 02Z AT THESE TERMINALS, BUT CONFIDENCE WAS TOO LOW TO INCLUDE
ANY IFR SNOW. SNOW IS STILL FALLING AT RDU, BUT THE BACK EDGE SHOULD
PUSH EAST OF THIS TERMINAL AROUND 03-04Z. CONDITIONS SHOULD IMPROVE
TO MVFR, ESPECIALLY ONCE THE SNOW TAPERS OFF. A MIXTURE OF SNOW AND
SLEET IS FAVORED AT RWI TILL ABOUT 05Z, WITH CONDITIONS RANGING FROM
IFR TO MVFR. FREEZING RAIN IS STILL EXPECTED TO PREVAIL AT FAY WITH
IFR CONDITIONS LIKELY TO PREVAIL BEFORE IMPROVING TO MVFR AFTER THE
FREEZING RAIN TAPERS OFF AT 04-05Z. SOME GUIDANCE SUGGESTS CEILINGS
LOWERING TO IFR OR LIFR OVERNIGHT AS PRECIPITATION COMES TO AN END
ACROSS ALL TERMINALS, BUT CONFIDENCE WAS TOO LOW GIVEN FORECAST
SOUNDINGS SHOWING PREDOMINANT MVFR STRATUS, WITH PERHAPS EVEN SOME
BRIEF VFR. SOME ISOLATED FREEZING DRIZZLE MAY OCCUR OVERNIGHT WITH
WEAK FORCING ALOFT BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN ANY TAF.
A BAND OF LIGHT SNOW IS EXPECTED TO REACH THE TERMINALS THU MORNING
INTO EARLY AFTERNOON WITH AN UPPER-LEVEL SYSTEM. CONDITIONS ARE
LIKELY TO RANGE FROM IFR TO MVFR, WITH LOWEST VISIBILITIES AT
GSO/INT/RDU. VFR RETURNS AT OR BEFORE THU MIDDAY, WITH NW WINDS
GUSTING TO 25-30 KT.
OUTLOOK: GUSTY NW WINDS WILL CONTINUE THU NIGHT, BUT GRADUALLY
DIMINISH BY EARLY FRI. VFR SHOULD PREVAIL THROUGH THE PERIOD.
RAH WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING UNTIL 1 PM EST THURSDAY FOR NCZ007>011-
026>028-041>043-078-089.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THURSDAY FOR NCZ021>025-
038>040-073>077-083>086-088.
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/SWIGGETT
SHORT TERM...KC
LONG TERM...HARTFIELD
AVIATION...KREN
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