024
FXUS62 KRAH 291619
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1220 PM EDT TUE SEP 29 2026
WHAT HAS CHANGED
* ABOVE AVERAGE UNCERTAINTY EXISTS WITH TIMING AND AMOUNTS FROM THE
NEXT CHANCE OF RAIN: THIS WEEKEND.
KEY MESSAGES
AS OF 245 AM TUESDAY...
1) WELL ABOVE AVERAGE AND UNSEASONABLY HOT TEMPERATURES WILL DEVELOP
THIS WEEK AND CONTINUE UNTIL A FRONT WAVERS OVER THE SRN MIDDLE
ATLANTIC WITH A CHANCE OF RAIN THIS WEEKEND.
DISCUSSION
AS OF 245 AM TUESDAY...
KEY MESSAGE 1... WELL ABOVE AVERAGE AND UNSEASONABLY HOT
TEMPERATURES WILL DEVELOP THIS WEEK AND CONTINUE UNTIL A FRONT
WAVERS OVER THE SRN MIDDLE ATLANTIC WITH A CHANCE OF RAIN THIS
WEEKEND.
A SUB-TROPICAL RIDGE WILL PROGRESS AND STRENGTHEN ACROSS THE SOUTH
ATLANTIC STATES THIS WEEK. THE RIDGE WILL THEN LOSE INFLUENCE THIS
WEEKEND, AS A WEAKENING, POSITIVELY-TILTED TROUGH SETTLES ACROSS THE
REGION AHEAD OF A VIGOROUS NRN STREAM TROUGH FORECAST TO AMPLIFY AND
PIVOT ACROSS THE GREAT LAKES.
AT THE SURFACE, A CANADIAN HIGH NOW CENTERED ACROSS THE OH VALLEY
AND GREAT LAKES WILL PROGRESS ACROSS AND OFFSHORE THE MIDDLE
ATLANTIC THROUGH MIDWEEK, THEN TO NEAR BERMUDA BY FRI. SLY FLOW
AROUND THE BERMUDA HIGH, AND AHEAD OF A WAVY FRONT THAT WILL SETTLE
INTO AND PROBABLY WAVER OVER THE SRN MIDDLE ATLANTIC THIS WEEKEND,
WILL CONTRIBUTE TO WARMING TEMPERATURES THROUGH THE WEEK AND TO
NEAR/AROUND 90 F BY THU AND ESPECIALLY FRI.
WHILE HOTTER, THE PRE-FRONTAL AIRMASS WILL NOT BECOME PARTICULARLY
HUMID, WITH ONLY MODEST LOW-LEVEL MOISTURE CHARACTERIZED BY SURFACE
DEWPOINTS IN THE LWR-MID 60S FORECAST AHEAD OF THE FRONT ON SAT.
WHEN COMBINED WITH WEAK MID-LEVEL LAPSE RATES OF GENERALLY LESS THAN
5.5 C/KM, INSTABILITY SHOULD REMAIN WEAK AND SUPPORTIVE OF MOSTLY
SCATTERED CONVECTION DURING THE AFTERNOON. A BETTER CHANCE OF RAIN
WILL RESULT BEHIND THE FRONT, PROBABLY LATER IN THE WEEKEND FOR CNTL
NC, WHEN AND WHERE SLY AND STRENGTHENING 850 MB FLOW WILL FAVOR
ISENTROPIC LIFT AND RAIN. SOME DEGREE OF COLD AIR DAMMING WOULD ALSO
RESULT, BUT UNCERTAINTY FOR THIS WEEKEND REMAINS REGARDING THE
FRONTAL LOCATION, POSSIBLE WEAK WAVE DEVELOPMENT ALONG THE FRONT,
AND THE EXTENT OF POST-FRONTAL CAD. REGARDLESS, THERE IS A
CONSISTENT SIGNAL IN MODEL GUIDANCE FOR THE FRONT TO MOVE OFFSHORE
BY EARLY MON, WITH ANOTHER CANADIAN HIGH POISED TO BUILD ACROSS MUCH
OF THE ERN US EARLY TO MID NEXT WEEK.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
AS OF 1220 PM TUESDAY...
HIGH CONFIDENCE IN VFR CONDITIONS HOLDING ACROSS CENTRAL NC
TERMINALS THROUGH AT LEAST THIS EVENING, ALTHOUGH AREAS OF SCATTERED
TO BROKEN CLOUDS BASED AT 5K-8KFT AGL WILL PERSIST ACROSS NE
SECTIONS (INCLUDING RWI AND RDU) THROUGH THE AFTERNOON, AS A MID
LEVEL DISTURBANCE SWINGS THROUGH. LATER TONIGHT, THE COMBINATION OF
LIGHT WINDS AND INCREASING LOW LEVEL MOISTURE OVER EASTERN AREAS
WILL PROMPT DEVELOPMENT OF PATCHY FOG PRODUCING A PERIOD OF IFR/LIFR
VSBYS 08Z-12Z, MAINLY AT RWI/RDU/FAY, WITH THE HIGHEST CONFIDENCE AT
RWI. ANY FOG SHOULD QUICKLY LIFT AND DISSIPATE BY 15Z. ELSEWHERE, AT
INT/GSO, FAIR SKIES SHOULD PREVAIL THROUGH MIDDAY WED. SURFACE WINDS
WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD.
LOOKING BEYOND 18Z WED, VFR CONDITIONS ARE LIKELY TO HOLD THROUGH AT
LEAST FRI, ALTHOUGH AREAS OF SUB-VFR VSBYS IN FOG ARE POSSIBLE EACH
MORNING ESPECIALLY IN THE EAST, WITH THE HIGHEST POTENTIAL FOR FOG
EARLY FRI MORNING. THE CHANCE FOR SHOWERS AND STORMS PRODUCING SUB-
VFR CONDITIONS WILL INCREASE BY SAT AND REMAIN HIGH THROUGH SUN,
AHEAD OF AN APPROACHING FRONT. -GIH
CLIMATE
RECORD HIGH TEMPERATURES:
SEPTEMBER 30:
KRDU: 89/1954
OCTOBER 1:
KGSO: 90/1986
KRDU: 90/1986
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...MWS
AVIATION...HARTFIELD
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