Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 310615 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 215 AM EDT WED AUG 31 2016 .SYNOPSIS...
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Tropical Depression 8 will track northeast into the Atlantic today as central NC remains in a relatively warmer and drier pattern. A cold front will move in for Thursday, before Tropical Depression 9 will move northeast near and along the front on Friday and Saturday.
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&& .NEAR TERM /THROUGH TONIGHT/... As of 920 PM Tuesday... Latest surface analysis shows a meager Tropical Depression 8 off the NC coast with a ridge of surface high pressure extending southwest into the Mid Atlantic. A light east to northeast flow at persists at the low to mid levels which has resulted in an increase in moisture across central NC. Further aloft, an upper level low was located across central SC and was drifting slowly northwest with weak ridging across central NC. This setup should result in generally fair weather overnight with isolated convection confined to the coastal region with partly to mostly clear skies overnight. Lows Wednesday morning will range in the upper 60s to lower 70s. -Blaes && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 1245 PM Tuesday... As Tropical Depression 8 tracks NE away from the Carolina coast, a baroclinic low attendant a weakening upper level low just offshore the Southeast coast and strengthening cyclonic flow aloft over the Mid-Atlantic is expected to track NE along/just offshore the Carolina coast Wed/Wed night. By 12Z Thu, the low is progged to be centered just south of Cape Lookout. Although the best potential for precipitation attendant the aforementioned low will remain in immediate vicinity of the Carolina coast, 12Z model guidance suggests isolated or scattered convection (primarily showers) may develop as far inland as the Coastal Plain. Additionally, diurnal convection is expected to develop in the higher terrain of the NC mountains in assoc/w differential heating and diffluent flow aloft Wed aft/eve, and some of this activity could drift into portions of the NW piedmont before dissipating Wed evening. With the above in mind, will continue to indicate a slight chance of showers/storms during the aft/eve hours in southeast portions of the Coastal Plain and in the Northwest Piedmont. Expect highs on Wed in the upper 80s to near 90F, lows Wed night in the lower 70s. -Vincent && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 245 PM Tuesday... Thursday-Thursday night: Amplifying northern stream trough and attendant cold front will progress southeast into the region late Thursday afternoon/evening and at the same time should cause what is now T.D. 9 or possibly soon to be Tropical Storm Hermine to to bend northeastward and move across northern Florida and along the Southeast Coast. At this time, minimal to no impact from this tropical system. Instead, frontal lifting underneath the entrance region of a seasonably strong 90kt jet streak extending down the Mid- Atlantic States will provide sufficient forcing within the moist 1.8- 2.0" PWAT airmass in place to support scattered to possibly numerous showers and storms across Central NC between 18z to 06z. With afternoon temps in the upper 80s to lower 90s and continued BL dewpoints in the lower to mid 70s, steep low-level lapse rates will result in 1000-2000 J/KG of MLCAPE across the area Thursday afternoon, highest across the southeast. Thus, could see a uptick in coverage and intensity late in the day as convection moves east-southeast into the Sandhills and coastal plain. Given 25 to 30kts of deep layer shear, can`t rule a few strong to severe storms during the afternoon/early evening, before nocturnal stabilization sets in. In the wake of the frontal passage, cooler air begins to seep into the area Thursday night with lows 65 to 70. Friday through Tuesday: While there are some differences in the forward speed/timing of what is now T.D. 9 as it interacts/merges with amplifying trough into the Eastern US, the official NHC track moves the system up the Southeast Coast and out into the Western Atlantic Friday and into Saturday. Central NC could see some lingering showers in the east on Friday as the front could temporary stall along the coast with the approach of the tropical cyclone from the south. Thereafter, will forecast dry conditions with cooler temps as Canadian high pressure builds south in the area. Highs Friday and through the weekend in the lower 80s north to mid 80s south. Lows in the lower to mid 60s. Temperatures should start to rebound early next week as upper ridging builds back into the region from the west. -CBL && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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As of 745 PM Tuesday... 24 hour TAF period: A few more MVFR visibilities already popping up this morning compared to yesterday as dewpoint depressions near zero are in place across the east. This would lead me to believe the KRWI will be soon to experience MVFR visibilities but all other TAF sites are carrying at least a 5 degree dewpoint depression so if KFAY or KRDU were to go down to MVFR it will be much later this morning. Otherwise another mostly dry day is expected although models do show a little more shower activity after 21 Z through the end of the TAF period. Will keep showers out of the TAFs at this time as the probability is less than 30 percent. Winds will begin easterly and shift to a more southeasterly direction by the end of the period. Wind speeds near 5 kts. Long Term: An uptick in convection is in order for Thursday as a cold front approaches from the northwest and then the influence of tropical depression 9 will affect at least eastern terminals on Friday through Saturday morning with some gusty winds and rain possible.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Ellis NEAR TERM...Blaes SHORT TERM...Vincent LONG TERM...CBL AVIATION...Ellis

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