509
FXUS62 KRAH 271755
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
155 PM EDT THU MAR 27 2025
SYNOPSIS
CANADIAN HIGH PRESSURE WILL BUILD OVER AND OFFSHORE THE CAROLINAS
TODAY. A WARM FRONT WILL LIFT NORTHEAST ACROSS THE CAROLINAS AND
MIDDLE ATLANTIC ON FRIDAY, WITH FOLLOWING BERMUDA HIGH PRESSURE THAT
WILL EXTEND ACROSS THE SOUTH ATLANTIC STATES THROUGH THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 1010 AM THURSDAY...
SOME ADJUSTMENTS HAVE BEEN MADE TO (LOWER) FORECAST SURFACE
DEWPOINTS AND ASSOCIATED RH, WITH THE LATTER LIKELY TO DECREASE INTO
THE MID TEENS TO LOW 20S PERCENT WITH HEATING INTO THE MID-UPR 60S
THIS AFTERNOON. THERE MAY ALSO BE AT LEAST OCCASIONAL GUSTINESS OF
WLY TO WSWLY WINDS INTO THE TEENS KTS.
CANADIAN HIGH PRESSURE AND ASSOCIATED DRY, CONTINENTAL AIR SITUATED
SQUARELY OVER THE NC PIEDMONT THIS MORNING WILL DRIFT ACROSS CNTL
AND ERN NC THROUGH THIS AFTERNOON, THEN OFFSHORE BY THIS EVENING.
THE 12Z-OBSERVED GSO SOUNDING SAMPLED A STRONGER HYDROLAPSE (IE.
DECREASING MOISTURE WITH HEIGHT) AND A DRIER MEAN MIXING RATIO THAN
WED; AND OBSERVED SURFACE DEWPOINTS THIS MORNING HAVE ALREADY BEEN
SEVERAL DEGREES LOWER THAN 24 HOURS AGO - ALL SUGGESTIVE OF SURFACE
DEWPOINTS THAT SHOULD BE LOWER (ON AVERAGE) TODAY THAN ON WED. BOTH
THE GSO AND MHX OBSERVED SOUNDINGS THIS MORNING ALSO SAMPLED 15-20
KTS OF WLY TO NWLY FLOW WITHIN THE FORECAST MIXED/BOUNDARY LAYER
DEPTH OF 7-8 THOUSAND FT AGL, WHICH SUGGESTS OCCASIONAL GUSTS OF
SIMILAR STRENGTH WILL PROBABLY RESULT WITH CONTINUED HEATING AND
MIXING THROUGH THE AFTERNOON. THE HRRR AND RAP TYPICALLY REPRESENT
BOTH SURFACE DEWPOINTS AND SURFACE WINDS/GUSTS WELL AND WERE
CONSEQUENTLY UTILIZED HEAVILY IN THE OFFICIAL GRIDDED FORECAST
UPDATE.
PREV DISCUSSION
/ISSUED 250 AM EDT THU MAR 27 2025/
* INCREASED FIRE DANGER IN EFFECT THROUGH THIS EVENING
NORTHWEST FLOW WILL PERSIST AGAIN FOR MUCH OF TODAY AT MID-LEVELS
WITH TROUGHING OFF THE COAST AND OVER THE NORTHWEST ATLANTIC.
RIDGING OVER THE CENTRAL PLAINS WILL SHIFT INTO THE MID MS VALLEY
TOWARD 12Z SAT. ROUGHLY 1028 MB HIGH PRESSURE WILL BE SITUATED RIGHT
OVERTOP NC TO START OUR DAY. AFTER A COLD START WITH AREAS OF FROST,
HIGHS SHOULD REBOUND NEAR NORMAL INTO THE MID 60S TO AROUND 70,
WARMEST IN THE SW. HIGH PRESSURE WILL GRADUALLY SHIFT OFFSHORE LATER
THIS AFTERNOON AND EVENING, WITH A LIGHT WEST-SOUTHWEST WIND AT 5-10
MPH. AN INCREASED FIRE DANGER WILL BE IN EFFECT THROUGH THIS EVENING
WITH RH LEVELS AROUND 20-24 PERCENT AND CONTINUED DRYNESS AND FIRE
ACTIVITY ACROSS THE CAROLINAS. SOUTHERLY FLOW WILL BE IN FULL SWING
TONIGHT WITH THE HIGH OFF THE COAST. CLOUDS WILL INCREASE TONIGHT,
ESPECIALLY ACROSS THE NORTH AS A WARM FRONT LIFTS INTO THE TN/OH
VALLEY REGION. SOUNDINGS SHOW SATURATION AROUND THE 700-MB LAYER.
THE CONTINUED STIRRING AND CLOUDS WILL FAVOR MUCH WARMER LOWS IN THE
LOW TO MID 40S.
SHORT TERM /FRIDAY AND FRIDAY NIGHT/
AS OF 250 AM THURSDAY...
HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL SHIFT TOWARD BERMUDA.
CONTINUED SSW SURFACE FLOW WILL BE IN PLACE, ALONG WITH CONTINUED
WARMING OF THE AIRMASS. MOISTURE RIDING AROUND THE NORTHERN
PERIPHERY OF THE 850-700 MB RIDGE WILL FAVOR MORNING MID-LEVEL
CLOUDS, ESPECIALLY ACROSS THE NORTH. THESE CLOUDS SHOULD THIN OR
ADDITIONALLY LIFT NORTHEAST AS FLOW AT 700-MB BECOMES MORE WESTERLY
AS OPPOSED TO NW. THUS, WHILE SOME CLOUDS MAY INITIALLY INHIBIT
WARMING, SUNSHINE SHOULD TAKE OVER AS THE AFTERNOON WEARS ON. THIS
ALONG WITH LOW-LEVEL THICKNESS CLOSE TO VALUES TYPICAL FOR EARLY MAY
SHOULD FAVOR MUCH ABOVE NORMAL HIGHS TO CLOSE OUT THE WEEK IN THE
MID TO UPPER 70S. SOME 80-DEGREE READINGS MAY BE POSSIBLE OVER THE
TRIANGLE AND SOUTHERN PIEDMONT TO SANDHILLS. WITH THE HIGH WELL
OFFSHORE AND TROUGHING OVER THE NORTHERN PLAINS, SOUTHWEST WINDS
WILL BE A LITTLE GUSTY, WITH GUSTS OF 15-22 MPH. WHILE DEWPOINTS
WILL RECOVER FROM THU INTO THE UPPER 30S NW TO MID 40S SE, RH LEVELS
WILL STILL BE SOMEWHAT DRY IN THE MID 20S TO LOW 30S. AN INCREASED
FIRE DANGER STATEMENT MAY BE NEEDED.
CLOUDS WILL BUILD BACK IN FRI NIGHT AS GUIDANCE SHOWS AN OPEN WAVE
REACHING THE LOWER MS VALLEY OVERNIGHT. THIS WITH CONTINUED
SOUTHERLY FLOW AND RISING DEWPOINTS SHOULD FAVOR 15-18 DEGREES ABOVE
NORMAL FOR LOWS IN THE MID/UPPER 50S.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
AS OF 250 AM THURSDAY...
SATURDAY THROUGH SUNDAY NIGHT: UNDER THE INFLUENCE OF BERMUDA HIGH
PRESSURE, THE WEEKEND WILL START OUT DRY AND VERY WARM. A SOUTHERN
STREAM SHORTWAVE TROUGH OVER THE LOWER MS VALLEY AND MID SOUTH WILL
CAST AMPLE MID AND HIGH CLOUDS OVER THE AREA. UNDER PARTLY TO MOSTLY
CLOUDS SKIES AND A MILD BREEZE, HIGHS SATURDAY ONCE AGAIN TOPPING
OUT IN THE 75-80 DEGREES, WHICH IS 10-12 DEGREES ABOVE NORMAL.
CLOUDS WILL THICKEN SATURDAY NIGHT WITH RAIN CHANCES INCREASING FROM
SW TO NE DURING THE DAY SUNDAY AS THE AFOREMENTIONED SOUTHERN STREAM
TROUGH EJECTS NE ACROSS THE AREA SUNDAY AFTERNOON, BEFORE EXITING
SUNDAY EVENING/NIGHT. WEAK INSTABILITY OF ONLY 100-200 J/KG SHOULD
LIMIT THUNDER CHANCES. RAINFALL AMOUNTS ARE EXPECTED TO BE LIGHT,
AVERAGING AROUND 0.25". HIGHS IN THE LOWER/MID 70S. LOWS SUNDAY
NIGHT IN THE 60S.
MONDAY AND MONDAY NIGHT: A SERIES OF CLOSELY SPACED MID/UPPER
SHORTWAVE TROUGHS WILL EJECT EAST FROM THE CENTRAL PLAINS AND INTO
THE NORTH-CENTRAL EASTERN US MONDAY AND TUESDAY. ASSOCIATED COLD
FRONT WILL SWEEP EAST THROUGH THE AREA LATE MONDAY AND MONDAY NIGHT.
CLOUDS AND RAIN FROM SUNDAY'S TROUGH LIFTING THROUGH THE REGION
COULD LINGER INTO MONDAY, AND POTENTIALLY TEMPER/LIMIT DAYTIME
HEATING AND DESTABILIZATION ACROSS CENTRAL NC MONDAY
AFTERNOON/EVENING. WILL HAVE TO CLOSELY MONITOR THESE DETAILS.
OTHERWISE, IF SUFFICIENT INSTABILITY CAN BE REALIZED SHEAR WILL BE
SUFFICIENTLY STRONG TO SUPPORT A THREAT FOR SEVERE STORMS ACROSS
CENTRAL NC. HIGHS RANGING FROM MID/UPPER 70S NW TO LOWER 80S SE.
LOWS MONDAY NIGHT WILL DEPEND ON THE TIMING OF THE FROPA. LOWS IN
THE MID/UPPER 40S NW TO LOWER/MID 50S SE.
TUESDAY THROUGH WEDNESDAY: A STRONG TRANSITORY ~1035MB SFC HIGH WILL
BRING A BRIEF STINT OF COOLER, NEAR-NORMAL TEMPS THROUGH MID WEEK.
THE NEXT RAIN PRODUCING SYSTEM WILL APPROACH THE AREA LATE WEDNESDAY
NIGHT INTO THURSDAY.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
AS OF 155 PM THURSDAY...
THE INFLUENCE FROM DRY, CANADIAN HIGH PRESSURE THAT WILL DRIFT OFF
THE COAST OF THE CAROLINAS BY TONIGHT WILL FAVOR CONTINUED VFR
CONDITIONS IN CNTL NC THROUGH FRI. A LITTLE VIRGA MAY ACCOMPANY A
BAND OF MID-LEVEL, 8-11 THOUSAND FT AGL CEILINGS THAT WILL
OVERSPREAD CNTL NC OVERNIGHT-FRI MORNING, BUT WITH NO OPERATIONALLY
SIGNIFICANT IMPACTS AT THE SURFACE.
A MODEST LOW-LEVEL JET AND RELATED STRONG TEMPERATURE INVERSION
TONIGHT WILL ALSO FAVOR MARGINAL LOW-LEVEL WIND SHEAR CONDITIONS
OVERNIGHT-FRI MORNING, ESPECIALLY ALONG THE AXIS OF THE JET NEAR RDU
AND GSO. SWLY SURFACE WINDS WILL THEN STRENGTHEN AND BECOME GUSTY TO
AROUND 20 KTS WITH DAYTIME HEATING BY MID TO LATE MORNING FRIDAY.
OUTLOOK: LOW-LEVEL MOISTURE WILL INCREASE, CHARACTERIZED BY SURFACE
DEWPOINTS IN THE 50S, SUCH THAT AREAS OF IFR STRATUS WILL BE
POSSIBLE BOTH SATURDAY AND SUNDAY MORNING. ADDITIONALLY, A NOCTURNAL
LOW-LEVEL JET COUPLED WITH A MODEST TEMPERATURE INVERSION WILL
PROMOTE A RISK OF MARGINAL LOW-LEVEL WIND SHEAR CONDITIONS THIS
WEEKEND. A CHANCE OF SHOWERS AND STORMS WILL RETURN SUN AND
ESPECIALLY WITH THE PASSAGE OF A COLD FRONT ON MON .
FIRE WEATHER
AS OF 1020 AM THURSDAY...
..INCREASED FIRE DANGER REMAINS IN EFFECT THROUGH THIS EVENING
LOW AFTERNOON RH VALUES IN THE MID TEENS TO LWR 20S PERCENT,
OCCASIONAL WIND GUSTS UP TO 15-20 MPH, AND DRY FUELS WILL YIELD
INCREASED FIRE DANGER TODAY.
ON FRIDAY, DEWPOINTS ARE EXPECTED TO MINIMALLY RISE AND SUPPORT
RECOVERY OF AFTERNOON RH IN THE MID 20S TO MID 30S PERCENT.
ADDITIONALLY, SWLY WINDS WILL STRENGTHEN AND BECOME MORE-FREQUENTLY
GUSTY TO AROUND 20 MPH. WHEN COMBINED WITH WARMER THAN PREVIOUS DAYS
AIR AND FUEL TEMPERATURES, ANOTHER DAY OF INCREASED FIRE DANGER
APPEARS LIKELY, ESPECIALLY OVER THE PIEDMONT AND WRN SANDHILLS.
COORDINATION OF SUCH WILL BE NEEDED WITH SURROUNDING NWS FORECAST
OFFICES AND THE NCFS LATER TODAY.
GRADUALLY RECOVERING RH LEVELS ARE EXPECTED SATURDAY AND ESPECIALLY
SUNDAY INTO EARLY NEXT WEEK, AS A STORM SYSTEM BRINGS POTENTIAL WET
WEATHER AND A REDUCED FIRE DANGER THREAT.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...MWS
NEAR TERM...MWS/KREN
SHORT TERM...KREN
LONG TERM...CBL
AVIATION...MWS
FIRE WEATHER...MWS/KREN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page