Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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039 FXUS62 KRAH 181046 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 646 AM EDT Fri Sep 18 2026 .WHAT HAS CHANGED... * Locations where strong to severe thunderstorms will be possible this afternoon and evening has been expanded to cover areas along and west of the I-95 corridor, including the Triangle, Fayetteville, and the Triad. && .KEY MESSAGES... As of 215 AM Friday... 1) Scattered to locally numerous showers and storms will be possible this afternoon/evening and be capable of strong to severe straight- line wind gusts and locally heavy rainfall amounts of > 1". 2) Monday into Tuesday will likely feature scattered to numerous showers and thunderstorms. Beneficial rain possible for some areas. Hot Monday, cooling by Tuesday especially north. 3) A NE flow and cold air damming will yield much cooler and cloudier conditions, possibly accompanied by periods of light rain and drizzle, by the middle of next week. && .DISCUSSION... As of 215 AM Friday... KEY MESSAGE 1... Scattered to locally numerous showers and storms will be possible this afternoon/evening and be capable of strong to severe straight-line wind gusts and locally heavy rainfall amounts of > 1". A pair of fronts are expected the shift across our area over the next 24 to 36 hours. The lead boundary will be a pre-frontal trough, currently stretching roughly from Richmond to Charlotte in the 05z obs, which will mix southeast throughout the morning and bring atypical hot and humid conditions within northerly flow across the forecast area. Trailing this boundary will be the synoptic cold front, which will likely be working through the Virginias and southern Ohio Valley through the daylight hours. In between these two boundaries, surface dew points should remain in the mid/upper 60s to low 70s throughout peak heating as temperatures rise well into the 90s. This should provide a moderately unstable air mass with instability ranging from 1000-2000 J/kg. Although isolated pulse air mass showers/storms can`t be ruled out anywhere through the afternoon (with convective temps in the low 90s), the greatest convective coverage will likely be along a the track of upstream showers and storms currently working through Ohio as of 06z. Mean-wind steering flow should continue to track this cluster towards the central Appalachians by early afternoon and then track generally south and into central NC during peak heating. Poor mid-lvl lapse rates and related marginal instability should preclude a more widespread severe threat, however, steep low-lvl lapse rates in excess of 9 C/km over the Piedmont could favor storms organizing along a common cold-pool and result in localized strong to severe straight-line wind gusts, despite weak tropospheric wind shear (5-10 kts). The synoptic cold front should start to working into the area from the north around or shortly after midnight and may support a continuation of shallow showers through the overnight period. KEY MESSAGE 2... Monday into Tuesday will likely feature scattered to numerous showers and thunderstorms. Beneficial rain possible, remaining hot Monday. Turning cooler later Tuesday, especially over north-central areas. Models continue to suggest a potentially moist period for our region Monday into Tuesday. This is due to the mid/upper trough approaching from the Midwest and Ohio Valley. One cold front is expected to reach NC Monday afternoon and possibly stall, with another cold front expected to backdoor the region late Tuesday into Tuesday night. There should be a couple of rounds of showers/storms, especially during the afternoon and evening Monday into Tuesday night. Some beneficial rainfall is expected, but as is typical with thunderstorms some areas will get the beneficial rainfall of 1 to locally 2 inches, while some others may be left out. Much more on this forecast through the weekend updates. It will likely continue very warm and humid Monday, with some cooler conditions Tuesday across the north (due to clouds/showers/storms). Monday highs should be in the mid 80s to lower 90s south. Highs Tuesday will be around 80 north to near 90 south. Lows in the mid 60s to around 70. KEY MESSAGE 3... A NE flow and cold air damming will yield much cooler and cloudier conditions, possibly accompanied by periods of light rain and drizzle, Tuesday night into Thursday. Once the cold front settles south of the region later Tuesday and Tuesday night, a low level NE flow will continue to feed low level moisture into the region. This would bring stable conditions and would mean that stratus, fog, and periods of light rain/drizzle or light showers will be likely Tuesday night into Wednesday and Thursday. The combination of the NE flow, moisture, cloudiness, and some light rain will keep daily highs in the 70s (or much below normal for the first time in weeks). Lows in the 60s, with some 50s possible north-central Wed-Fri. && .AVIATION /11Z FRIDAY THROUGH TUESDAY/... As of 640 AM Friday... No major changes on timing of showers/storms this afternoon and evening based on limited new hi-res guidance and time-of-arrival tracking of the ongoing storm cluster in WV this morning. Did introduce MVFR/IFR cigs towards the end of the TAF period when confidence was greatest, although it may develop earlier than currently forecast. Previous discussion as of 215 AM follows... The primary driver in otherwise prevailing VFR conditions will come from early afternoon convection that may linger into the evening. Showers and storms are likely to develop around the central Appalachians aided by prior convection currently moving through the Ohio Valley and shift southeast into this evening, although preceding air mass showers/storms will also be possible. Scattered to locally numerous showers/storms will be possible at any terminal and bring the risk for lightning, strong gusty and erratic winds (25- 40 kts), and heavy downpours reducing vsby. Outlook: A risk of convection will linger along the passing fronts on Saturday, especially over the srn half of NC and including at FAY. Nely flow behind the fronts will otherwise increase the likelihood of IFR-MVFR ceilings, lowest and most prolonged over the Piedmont (especially at INT/GSO), both Saturday and Sunday mornings. Stronger nely flow, and an increasing likelihood of cold air damming, will favor additional sub-VFR conditions and periods of light rain during the middle of next week (as early as Tue). && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...AS/Badgett AVIATION...AS/MWS