Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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909 FXUS62 KRAH 201856 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 256 PM EDT Sun Sep 20 2026 .WHAT HAS CHANGED... * No major changes. && .KEY MESSAGES... As of 255 PM Sunday... 1) Can`t rule out an isolated shower or storm in the NW Piedmont late this afternoon and early this evening. 2) An approaching cold front will bring the potential for strong to severe thunderstorms on Monday, followed by a chance for heavy rainfall on Tuesday. 3) Cold-air damming will develop by the middle of the week, bringing several days of well below normal temperatures. && .DISCUSSION... As of 255 PM Sunday... KEY MESSAGE 1... Can`t rule out an isolated shower or storm in the NW Piedmont late this afternoon and early this evening. Subtropical ridging extends from TX into the mid MS Valley as a mid/upper low is centered over the eastern Gulf. Scattered convection is beginning to develop over the western NC mountains, while an area of decaying showers associated with a ripple in the flow aloft is located over southern WV and northwestern VA. Many high-res models have some more isolated showers and storms developing over SW VA and NW NC later this afternoon, perhaps being enhanced by the previously mentioned upper disturbance. Given SBCAPE of 1000-2000 J/kg and a tongue of relatively higher PW values around 1.7" across the NW Piedmont, a few of these showers and storms may make it as far as our NW Piedmont before diminishing with loss of daytime heating. The best chance will be from about 6-10 PM. No organized severe weather is expected, but can`t rule out isolated gusty winds given marginal DCAPE of 600-800 J/kg. KEY MESSAGE 2... An approaching cold front will bring the potential for strong to severe thunderstorms on Monday, followed by a chance for heavy rainfall on Tuesday. As a cold front slowly moves south across the Appalachians, Monday should be the last day with widespread upper 80 and 90 degree temperatures across central North Carolina. Although Monday morning will start off sunny, as the front begins to drop to the south, cloud cover will increase and showers/storms will begin to fire early in the afternoon along the VA/NC border. The greatest chance for rain will be along the state border, although most locations will have at least some chance for rain, particularly in the evening. The wind shear that could provide better organization for thunderstorms should remain to the north across Virginia, although MUCAPE locally will range from 1000 to 2000 J/kg. There will still be the potential for some isolated strong to severe thunderstorms across central North Carolina, particularly to the west of US-1. The most likely timing for severe thunderstorms should be between 2-6pm with the threat coming from damaging winds. In addition, cannot rule out the potential for some flash flooding near and around the Triad with the urban environment allowing for a better chance of excessive rainfall occurring. With the front moving south into North Carolina Monday night into Tuesday, that will put the forecast area onto the cool side of the boundary, which should reduce/eliminate the chance for severe weather on Tuesday. However, widespread rainfall is expected, and along the cool side of the boundary, high rainfall rates will still be possible, with the entire area will be under a marginal (level 1 of 4) risk for excessive rainfall, primarily Tuesday afternoon. KEY MESSAGE 3... Cold-air damming will develop by the middle of the week, bringing several days of well below normal temperatures. With the front slipping to the south of the area late Tuesday, a ridge of high pressure will extend south into the Carolinas from a strong high that will remain over Quebec for several days. While models are coming into better agreement that a low pressure system will develop off the Atlantic coast Thursday and move north, there is good model agreement that a sustained period of northeast wind and widespread cloud cover will occur Wednesday and Thursday. Wednesday will be the first full day of fall, and it will feel like it - locations north and west of I-85 are unlikely to rise out of the 60s both Wednesday and Thursday, with the rest of the area only rising into the 70s. Widespread light rain is likely on Wednesday, with conditions beginning to dry out on Thursday. The pattern, both with temperature and precipitation, should begin to moderate for Friday through Sunday, primarily based on model predictions of the Atlantic low moving towards New England and pushing the ridge of high pressure to the west. The end of this week looks to favor mostly sunny skies, minimal chances for rainfall, and highs in the 70s. Roxboro could see its temperature dip into the 40s on Saturday morning for the first time in several months. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... As of 220 PM Sunday... Through 18Z Monday: VFR conditions will prevail across central NC through this evening, with mainly just some fair weather cumulus. The only chance of precipitation is the potential for an isolated shower or storm in the NW Piedmont (including INT and GSO) around 22z-02z. Late tonight and early Monday morning, patchy fog and very low stratus will be possible once again, with the best chance in the Sandhills and Coastal Plain (including FAY and RWI). However, guidance differs on the extent of fog and low stratus, and its occurrence was isolated this morning with RWI the only TAF site reporting any restrictions. So confidence is fairly low at this time. Outlook: A cold front approaching Monday will bring a better chance of showers and storms to the entire area. Unsettled weather may persist under a CAD-regime developing Tuesday-Wednesday, where periods of sub-VFR stratus and fog may exist into late week, especially each early morning. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Danco/Green AVIATION...Danco/np