973 FXUS62 KRAH 151102 AFDRAHArea Forecast Discussion National Weather Service Raleigh NC 702 AM EDT Wed Oct 15 2025
.SYNOPSIS... Weak high pressure will extend across the southern Appalachians and Carolinas ahead of a moisture-starved, backdoor cold front that will move south through the area tonight. Canadian high pressure will follow and build across and offshore the Middle Atlantic Thursday through Saturday.
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.NEAR TERM /THROUGH TONIGHT/... As of 335 AM Wednesday...
A weak and moisture-starved mid-level trough will progress across NC this afternoon and evening, in nwly flow between a cyclone forecast to develop over ME by the end of the period and a srn Plains sub- tropical high that featured observed 500 mb heights of 594-596 dam last evening that exceeded most on record outside of the summer months from the srn Plains to the lwr-mid MS Valley.
At the surface, high pressure will weaken over the Southeast today, while a trough will develop and strengthen in the lee of the srn Appalachians. Meanwhile, Canadian high pressure will build from the upr MS Valley to the Carolinas, led southward by an ill-defined and moisture-starved backdoor cold front that will move south through the area early tonight.
While skies should average partly to mostly sunny throughout cntl NC, continued moist, nnely flow and the wrn edge of stratocumulus ceilings now over ern NC will probably develop wwd into the ern reaches of RAH`s Coastal Plain later this morning, before collapsing toward the coast through the afternoon-evening. While that cloud cover will likely keep temperatures there several degrees cooler than across the rest of cntl and wrn NC through early this afternoon, 2-3 hours of afternoon sunshine there allow high temperatures to warm into the mid 70s, ranging to upr 70s and to around 80 from INT to AFP and especially points wwd to CLT and HKY.
The passage of the backdoor cold front early tonight will probably be a mostly uneventful one, as it will be a dry one; and point forecast soundings indicate stronger nely flow/momentum will ride atop a nocturnally-cooled and stable near surface layer (ie. post- frontal gustiness will be isolated if at all). There will, however, be several degree cooling behind the front, with low temperatures in the mid 40s to lwr 50s.
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.SHORT TERM /THURSDAY AND THURSDAY NIGHT/... As of 350 AM Wednesday...
Dry, nwly to nnwly flow aloft will persist over cntl NC, between a progressive ridge that will extend from the cntl Gulf Coast to the Great Lakes by 12Z Fri and a cyclone that will dig across the nwrn Atlantic.
At the surface, the center of Canadian high pressure will progress from the Great Lakes to the cntl Appalachians, while its associated ridge will extend throughout the Middle and South Atlantic states. Dry and cool, and cooler than average, nly flow will result across cntl NC, with high temperatures in the mid 60s to lwr 70s and lows mostly in the upr 30s to lwr 40s.
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.LONG TERM /FRIDAY THROUGH TUESDAY/... As of 340 AM Wednesday...
Dry and mostly sunny conditions will continue on Friday under the influence of NW flow aloft between a high-amplitude ridge over the TN/OH Valleys and a deep cyclone in the Atlantic. At the surface, a Canadian high will move SE from the northern Appalachians to the southern Mid-Atlantic. This will bring another cool day to central NC with highs only ranging from lower-to-mid-60s in the far NE to near 70 in the far SW. Dew points will also be quite low, in the 30s to lower-40s. A weak mid-level perturbation will result in some high clouds on Friday night, but no precipitation is expected. Lows will be a bit milder than Thursday night and close to normal, generally in the 40s.
Saturday will again be dry and sunny, but the mid/upper ridge will then begin to flatten as it moves across the Northeast US and Mid- Atlantic. This is in response to phasing shortwaves over the Central US that result in a deep trough (possibly even closed low) that moves east and stretches across the Upper Great Lakes and TN Valley by Sunday. This will induce a surface cyclone over the Upper Great Lakes early Sunday which deepens and moves NNE into Canada. A cold front to its south will move east and cross central NC on Sunday night. So clouds will increase on Saturday night and Sunday, with a chance of showers from Sunday afternoon into Sunday night. Models are in fairly good agreement on timing, so increased POPs to 30-50% (highest north) on Sunday evening, which is when a majority of GFS/ECM/CMC ensemble members depict precipitation. Guidance has trended a bit wetter compared to last night, particularly the ECMWF which depicts a deeper trough and secondary low developing over the Mid-Atlantic. Still, rainfall amounts should be limited with the best upper forcing to our north and meager instability (less than 500 J/kg of CAPE). Even the 90th percentile of ensemble members is a half inch to an inch on the ECM and a quarter to half an inch on the GFS and CMC. So not expecting a significant dent in the ongoing abnormally dry and drought conditions across our region. As for temperatures, the surface high moving to our east and SW flow ahead of the front will turn us warmer on Saturday and Sunday with highs in the 70s. Lows will be in the upper-40s to mid-50s.
Monday and Tuesday will turn sunny and cooler behind the front. Forecast highs are in the upper-60s to lower-70s on Monday and lower- to-mid-70s on Tuesday, with lows in the mid-40s to 50 on Monday night.
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.AVIATION /11Z WEDNESDAY THROUGH MONDAY/... As of 700 AM Wednesday...
A band of MVFR ceilings, in continued moist, nnely flow over ern NC and sern VA, may edge swwd and across RWI for a few hours later this morning. Otherwise, nly surface winds will strengthen with daytime heating and may gust at times mainly between 13-18Z at the ern three TAF sites.
Outlook: Canadian high pressure will favor VFR conditions in cntl NC as it builds across and offshore the Middle Atlantic Thu through Sat. A chance of showers and flight restrictions will result ahead of and along a cold front that will move across the area late Sun and Sun night.
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.RAH WATCHES/WARNINGS/ADVISORIES... None.
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SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...MWS LONG TERM...Danco AVIATION...MWS
NWS RAH Office Area Forecast Discussion