Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 250159 AFDRAH AREA FORECAST DISCUSSION National Weather Service Raleigh NC 959 PM EDT Fri May 24 2019 .SYNOPSIS... A backdoor cold front will move through central NC tonight, bringing a slightly cooler airmass to the area for Saturday but a strong upper level ridge will help to keep persistent hot and mostly dry conditions through the weekend and well into next week. && .NEAR TERM /THROUGH TONIGHT/... As of 1000 PM Friday... A backdoor cold front is right on the doorstep of the northeastern border of the CWA this evening. This will continue to advance southwestward through the area overnight and is anticipated to make it to near the South Carolina border by sunrise on Saturday. Not enough moisture to support any more precipitation overnight therefore expect mostly clear skies and temperatures bottoming out in the mid to upper 60s with a few 70 degree readings possible in the south. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 320 PM Friday... The NW flow aloft today backs to a more wly direction Saturday as the ridge axis drifts east and extends across our region. While this will tend to suppress convective development, a minor perturbation currently approaching the crest of the ridge over the TN Valley is projected to cross our region Saturday afternoon. This system, interacting with the available moisture and weak-moderate instability will support the development of a few t-storms late Saturday into Saturday night. The main factor that would inhibit convective development will be a pocket of warm air aloft. Some model forecast soundings have this "lid" weakening by early evening, potentially allowing isolated convection to fire. if this occurs, potential for isolated convection to occur across the region into the overnight hours. Light nly flow initially behind the departing backdoor cold front will lead to slightly cooler afternoon temperatures Saturday across the far north-northeast. Meanwhile, late summer-like temperatures expected again across the south. Highs Saturday will vary from around 90 north, to the low-mid 90s south. Overnight temperatures Saturday night in the upper 60s to around 70. && .LONG TERM /SUNDAY THROUGH FRIDAY/... As of 330 PM Friday... Hot weather and generally low pops will continue during much of this period, with the heat likely peaking Tue/Wed, but a trend toward more seasonable temps and an uptick in pops will emerge late in the week. We should see a lingering small chance of showers/storms in the far E early Sun morning as the isolated storms Sat night depart to the E. Otherwise, the mean mid level ridge will hold firm over the Gulf States and Southeast through at least mid week, albeit with minor wavering of its axis to the W then to the E. A shortwave trough (likely convectively induced) over the central Plains Sat night will cross IN/OH Sun before sliding off the Mid Atlantic coast late Sun night. A surface low and backdoor front will accompany this feature, but the front is not expected to dip into NC, holding just to our N through Mon morning. Nevertheless, the preceding surface trough will push SE through central NC to near the coast, potentially bringing some slight cooling to far N and NE sections, and a few showers or storms can`t be ruled out near the VA border late Mon into Mon night given the relative height weakness near the Eastern Seaboard. The front retreats well back to the N and NE by early Tue, with a strong low level thermal ridge setting up through central NC, along and E of the surface pressure trough, as the mid level ridge axis inches back E and strengthens overhead. While Tue/Wed look like the hottest days, the strong heating and mixing may hold dewpoints down just enough during the hottest part of the day to keep heat indices just under advisory threshold over much of the area. Still, E and S portions of the CWA may need a heat advisory given the consecutive days of high heat and decreasing cooling at night, creating extra stressors on people and pets. The Western US low/trough finally shows signs of filling midweek, with a portion ejecting NE and merging with burgeoning polar low pressure over south central Canada. The exact placement and depth of this low varies quite a bit among the models as we head into Thu/Fri, but it appears likely that it will be deep enough as it shifts E to tamp down and flatten the SE ridge, allowing a mid level shear axis and corresponding surface cold front to push ESE into and across VA/NC Thu/Fri. Strengthening mid level flow, an erosion of warm capping aloft, and increasing low level moisture influx should help prompt better shower/storm coverage as the column moistens and stabilizes, better supporting convection. Will bring in chance pops (still at or below climatology) late Thu through Fri. Highs are expected to be generally in the 90s areawide through Thu, but readings should approach or perhaps exceed 100F over S and E sections Tue and Wed. Thicknesses drop but stay above normal late in the week, so still expect highs in the upper 80s to near 90. Daily lows will be in the upper 60s to lower 70s, but mid 70s will be common in many areas Wed and Thu mornings. -GIH && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 755 PM Friday... High confidence in VFR conditions dominating over the next 24 hours, although a couple of time periods present a small chance of adverse aviation weather. Isolated pockets of fog are possible early Sat morning 10z-12z at RDU/RWI/FAY, but the potential of it being a prevailing condition appears low at this time. By late Sat, isolated storms are possible, tracking NW to SE over central NC, mainly after 19z at INT/GSO and after 21z at RDU/RWI/FAY. Any storms are expected to be few in number and circumnavigable and are unlikely to be a prevailing condition for more than a half hour. Otherwise, any cigs will be well into VFR territory. Surface winds will become light mainly from the NW shifting to N then NE overnight as a frontal zone drops SW into the area. This front will dissipate on Sat, allowing surface winds to be from the SW for much of the day. Looking beyond 00z Sun: MVFR stratus is possible early Sun morning, mainly 08z-13z at RWI/FAY/RDU. Otherwise, aside from low chances of a passing shower or storm, VFR conditions will prevail over central NC through Wed. -GIH && .CLIMATE... Here are the record high temperatures and the year they were set for the period May 24th-29th: DATE RDU GSO FAY MAY 24TH 95/1944 93/1915 99/1938 MAY 25TH 93/2011 96/1926 98/2011 MAY 26TH 94/1953 95/1926 98/1926 MAY 27TH 96/1916 100/1911 100/1953 MAY 28TH 99/1941 98/1916 102/1941 MAY 29TH 98/1941 99/1914 102/1941 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Ellis NEAR TERM...Ellis SHORT TERM...WSS LONG TERM...Hartfield AVIATION...Hartfield CLIMATE...RAH

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