025 FXUS62 KRAH 141120 AFDRAHArea Forecast Discussion National Weather Service Raleigh NC 720 AM EDT Tue Oct 14 2025
.SYNOPSIS... Low pressure will meander off the Middle Atlantic coast today, while high pressure will build from the OH and TN Valleys to the southern Appalachians. A dry, backdoor cold front will move south across the region Wednesday evening, followed by Canadian high pressure that will build across and offshore the Middle Atlantic Thursday through Saturday.
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.NEAR TERM /THROUGH TONIGHT/... As of 355 AM Tuesday...
The models indicate a shortwave perturbation, now evident over ern PA in GOES-E WV data, will dig sewd and across and offshore the Middle Atlantic coast this morning and become absorbed by a closed mid/upr-level low cyclone centered about 250 miles east of the DelMarVA. Upstream, a sub-tropical high centered at 591 dam at 500 mb over ern TX will strengthen another few decameters and probably shatter daily record 500 mb heights from the srn Plains to the mid MS Valley today, as standardized 500 mb height anomalies there reach 3 sigma. A ridge extending newd from the high will progress across the Middle Atlantic today and Carolinas tonight. Associated rising heights and subsidence will cause an already-pronounced subsidence inversion, evident around 10 thousand ft on 00Z-observed RAOBs over the region, to strengthen and lower with time.
At the surface, multi-centered low pressure, anchored this morning by a ~1006 mb low about 275 miles east of HSE, will wobble generally ewd and away from the Middle Atlantic coast through 12Z Wed, while deepening 10-12 millibars.
Moisture in generally nly flow trapped beneath the lowering subsidence inversion, between the offshore cyclone and strengthening sub-tropical ridge, will maintain multi-layered ceilings over the ern two thirds of cntl NC through early to mid-afternoon (all but the srn and nw Piedmont), followed by east to west clearing mid- afternoon through evening. Those ceilings will be accompanied by an area of light rain and drizzle, now evident in regional radar data wrapping cyclonically in regional radar data from NJ swwd through cntl-ern MD and nrn VA, then swd through ern VA and most recently nern NC. The area of rain appears to be forced primarily by isentropic upglide/moisture transport centered in the 295-300 K (925- 850 mb) layer; and the models suggest this upglide will continue swd into the nrn and cntl Coastal Plain of NC this morning, where a chance of light rain and drizzle will remain in the forecast through ~15Z.
High temperatures will again follow a similar distribution as the clouds/ceilings and range from generally persistence mid/upr 70s in the srn and wrn Piedmont to mid/upr 60s in the Coastal Plain, followed by low temperatures in the 50s.
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.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 400 AM Tuesday...
The mid-level shortwave and associated surface low will push ENE farther into the Atlantic on Wednesday and Wednesday night. Meanwhile mid-level ridging will build east from the Southern Plains to the lower MS Valley, with a Canadian surface high slowly drifting SE over the Upper Great Lakes. NW flow aloft between these two features will result in dry weather and sunny skies across central NC on Wednesday. High temperatures will be slightly above normal, in the mid-to-upper-70s. Meanwhile a backdoor cold front will drop south through the Mid-Atlantic, reaching central NC on Wednesday night, but it will be dry. This will keep northerly winds elevated overnight, and some brief gustiness is possible with the frontal passage. Lows will be in the upper-40s to lower-50s.
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.LONG TERM /THURSDAY THROUGH MONDAY/... As of 400 AM Tuesday...
Thursday through Saturday will be dry and mostly sunny across central NC under the continued influence of the Canadian surface high and NW flow aloft between ridging to our west and troughing to our east. The mid/upper ridge axis will move east to the TN Valley and Great Lakes by Friday, then begin to flatten on Saturday as it moves across the Northeast US and Mid-Atlantic. This is in response to a closed mid/upper low that tracks from south-central Canada to the Upper Great Lakes this weekend, with associated deep troughing over the Eastern US. While the typical timing differences exist in the models this far out, a cold front to the south of the low looks to pass through central NC on Sunday night. Some showers are possible with its passage, but with its progressive movement, the best upper forcing to our north, and meager instability (a few hundred J/kg of CAPE or less), rainfall amounts don`t look too impressive. GFS/ECM ensemble mean QPF continues to be only in the tenth to quarter inch range, and even the 90th percentile is only around half an inch. This likely won`t be enough to make a significant dent in the ongoing abnormally dry and drought conditions across our region. Monday should turn clear and dry behind the front.
As for temperatures, they will turn much cooler on Thursday and Friday behind the backdoor front, with highs ranging from mid-60s NE to lower-70s SW. Dew points will only be in the 30s and 40s. Thursday night will be the coolest of the period owing to good radiational cooling conditions from the surface high which will be centered over the northern Appalachians. With low-level thicknesses in the 1340-1350 m range, forecast lows are in the upper-30s to lower-40s, and isolated frost can`t be ruled out in the coolest outlying spots of the Piedmont. As the surface high moves off the coast of the Carolinas and we get SW flow ahead of the next cold front, conditions will turn warmer on Saturday and Sunday with highs in the mid-to-upper-70s. Lows will be in the mid-40s to lower-50s on Friday night and mid-to-upper-50s on Saturday night. Monday will turn cooler again behind the front with highs in the upper-60s to lower-70s.
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.AVIATION /11Z TUESDAY THROUGH SATURDAY/... As of 720 AM Tuesday...
Moist, nly flow and associated IFR-MVFR ceilings over ern VA/NC, lowest nearest the coast, will spread sswwd and across RDU and FAY by around 15Z. Those ceilings, ones which may be accompanied by patchy light rain or drizzle at RWI this morning, will then gradually lift and scatter/clear to VFR from west to east through the day, first at RDU and last at RWI and FAY. VFR conditions are meanwhile expected to persist at GSO and INT. Nly surface winds will strengthen and become gusty into the teens to around 20 kts, strongest at RWI, with daytime heating around 14Z. Surface winds will continue to gust, at least occasionally so, through sunset.
Outlook: Stratocumulus based around 2500-3500 ft AGL will probably linger for most of the night over ern NC; and some may redevelop wswwd to near and especially just east of RWI and RDU Wed morning. A prolonged period of VFR conditions will otherwise be likely throughout cntl NC the rest of the week.
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.RAH WATCHES/WARNINGS/ADVISORIES... None.
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SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...Danco LONG TERM...Danco AVIATION...MWS
NWS RAH Office Area Forecast Discussion