Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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104 FXUS62 KRAH 081808 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 209 PM EDT Sat Jun 8 2024 .SYNOPSIS... Weak high pressure will remain over the region through tonight, then shift offshore tomorrow. A cold front will move through the area late in the day Sunday, bringing showers and storms to the area along with a return of drier air to start the week. && .NEAR TERM /THROUGH TONIGHT/... As of 209 PM Saturday... Early afternoon water vapor imagery shows a trough and an area of decaying convection over central KY/TN, with increasing high clouds downstream over the Carolinas. At the surface, high pressure remains in place to our west which has kept NC within an airmass featuring well below normal dewpoints for early June. Temperatures have risen well into the low to mid 80s as of 18Z, on their way to the mid/upper 80s before the day is over. For the rest of the day/tonight, expect varying amounts of high clouds as the decaying complex of storms moves through the area. Deep convection has long since dissipated and the remaining showers that are present on radar west the mountains should fall apart quickly as they cross the mountains and downslope into the Piedmont of NC. As such, PoPs remain in the lower single digits for the evening/overnight hours. Aside from an increase in cloud cover, and a corresponding increase in temperatures overnight, sensible weather impacts should be minimal. Temps tonight will be a bit warmer than those seen this morning with lows bottoming out in the mid/upper 60s. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 209 PM Saturday... ...Marginal Risk of severe storms across central/southern NC on Sunday... A slow moving upper low over the Great Lakes will move into eastern Canada during the day Sunday. A shortwave will round the base of the trough, cross the mountains, and arrive in central NC some time mid/late afternoon on Sunday. Ahead of the attendant surface cold front, temps will rise well into the low to mid 90s but more noticeably, moisture will return to the area as the aforementioned surface ridge shifts offshore and return flow sets up. PW`s will climb from around 1.0 inches today to nearly 1.75+ inches tomorrow afternoon. While there will be some remnant cloud cover across the area tomorrow from upstream convection, it still appears that there will be sufficient time and breaks in the clouds to support MLCAPEs in the 500-1000 J/KG range immediately ahead of the surface front as it moves through the area. Deep layer shear isn`t the most impressive but 0-6km values should reach 30-40 kt so there should be some amount of organization to whatever storms form along and ahead of the front. Primary threat with any storms that develop tomorrow will be in the form of damaging winds. As the front moves through the area, precip chances should taper off from northwest to southeast through the evening/overnight hours, eventually drying out completely by daybreak. Lows tomorrow night will range from the low 60s in the north to the upper 60s in the south. && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 145 PM Saturday... Monday through Wednesday: Aloft, as the amplifying upper trough swings eastward through the East Coast Mon and Tue, a pair of s/w disturbances will move through the base of the trough over central NC. The second s/w will be more potent, however with limited moisture to work with, chances for any showers with it are low. As the trough moves offshore Wed, weak, transient ridging will move through the area ahead of the next disturbance(s). At the surface, a weak area of low pressure may trail behind the cold front and linger over central NC on Monday, then shift eastward offshore as a reinforcing cold front pushes through the area Mon night/Tue. The low should sit offshore through Tue as the surface high builds eastward from the OH Valley to the northern mid-Atlantic/Northeast US. As the high shifts offshore Wed, it should finally push the low away from the coast. Expect a warm front to lift toward/into the area Wed night. Best chances for a shower or storm should be confined to the southern and eastern portions of central NC Mon night and Tue aft, coincident with the s/w passages aloft and somewhat favorable diurnal timing. Otherwise, the forecast remains dry through Wed. Temperatures should be near to slightly below normal for Mon and Tue, increasing back to slightly above normal by Wed. Thursday onward: Model solutions begin to diverge for the latter half of the week. Aloft, a disturbance over the lower MS Valley/Deep South could deepen if/as it moves over the Gulf Thu/Fri and meets up with a northward lifting disturbance over the eastern Gulf. There is disagreement wrt what happens to the low(s) Fri night/Sat, either lingering over the Gulf or lifting newd through FL to off the Southeast US coast. Meanwhile to the north, a northern stream s/w will track eastward through southeast Canada Wed/Thu as a secondary low follows behind it Thu/Fri. If these lows merge over Hudson Bay, the attendant trough could amplify southward through the mid- Atlantic Fri/Sat. There could be some interaction between the northern stream trough and the disturbance over the Gulf/Southeast, but for now there is too much uncertainty to say for sure how it will play out. Chances for showers/storms will depend on this interaction, so will err toward climatology until there is better agreement one way or the other. Temperatures should remain above normal Thu through Sat. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... As of 1226 PM Saturday... High confidence in VFR weather at all TAF sites through mid day Sunday. High clouds will thicken later this afternoon into tonight but cigs will only fall to around 15kft. There will be an increasing chance of showers on Sunday as a cold front approaches the area but this won`t occur until after the TAF period. Light winds generally less than 5-7 kts through the period. Outlook: Showers and isolated storms associated with he cold front could bring intermittent periods of non-VFR weather Sunday night through early Monday morning. Otherwise, much of the upcoming week should feature VFR conditions. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Leins NEAR TERM...Leins SHORT TERM...Leins LONG TERM...KC AVIATION...Leins