Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 260751 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 351 AM EDT FRI AUG 26 2016 .SYNOPSIS...
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A strong upper level ridge will extend across the region through the weekend.
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&& .NEAR TERM /THROUGH TONIGHT/...
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As of 345 AM Friday... A strong 595dm ridge at 500mb will shift overhead today, while a 850mb thermal ridge characterized by temps around 20C sets up from the TN Valley to central VA. 1000-850mb thicknesses are expected to start out around 1420m this morning, 15m higher than Friday, which supports the warmer MET guidance and highs in the mid to maybe even some upper 90s. Dewpoints in the lower 70s will push heat indices back toward 105 in the coastal plain. Forcing for convection is generally non- existent, but a few storms may strong within a ribbon of moisture, noted on water vapor, shifting from the blue ridge toward the southern Piedmont. Any convection would be very isolated and barely warrants any mention in the forecast. The upper ridge will continue its migration toward the northeast tonight, while a weak surface trough slips into the area form the north and winds begin to turn to northeasterly late. Lows 70-73
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&& .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
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As of 345 AM Friday... With the upper ridge to our north on Saturday, northeasterly flow will set in, though with very little change in airmass and highs again in the mid 90s. A slight dip in 850mb temps and reduction of the mid-level cap should allow isolated to widely scattered convection to fire during the afternoon, mainly with an axis of weak to moderate instability across the southern Piedmont and coastal plain. Convection will be diurnally driven and dissipate by early evening, with northeasterly flow supporting a chance of some low clouds over the coastal plain by early Sunday morning. Lows 70-73.
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&& .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 235 PM Thursday... Saturday through Sunday night: The weekend is setting up to be mostly dry as an upper level ridge sits directly on top of central NC. At the surface a high pressure system will start Saturday over the Great Lakes before progressing to the northeast through New England and the Canadian Maritimes. Models try to generate a few showers, particularly on Saturday afternoon across the western portion of the CWA. Will put slight chance in the forecast but confidence on this actually occurring is fairly low given the strong subsidence overhead. Saturday will be hot with maximum temperatures in the mid 90s but dewpoints should stay in the low 70s. This will result in heat indices creeping into the 100-105 degree range but probably wont be enough for a heat advisory. Temperatures will drop back to near 90 degrees on Sunday afternoon. Monday through Thursday: Model solutions begin diverging early next week so details will be hard to pin down at this point but we do know that the upper level ridge should relax and upper flow will become more zonal north of the area. To the south, the pattern will largely be dictated by where the current tropical invest winds up. Forecast model track spread is very large at this point as is the intensity guidance. Have increased chances for precipitation into the chance range for the end of the forecast period to account for any possible effects of the tropical system. Once the ridge breaks down the storm will be allowed to recurve the question is how far west will it be by that time and how quickly will it recurve. If the storm recurves before reaching the Florida Peninsula we could see dry weather here in NC as the storm goes out to sea. However if the storm recurves in the Gulf further west, then we could see rainfall ahead of the storm as early as Thursday morning. Highs near 90 each day with lows in the lower 70s. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... As of 200 AM Friday... Strong high pressure over the region will lead to light/variable predominately VFR conditions today an tonight, with just some scattered clouds above 4k ft drifting east across the Piedmont this morning. A chance for some isolated pockets of MVFR vsbys also continue this morning, particularly after 09z at FAY AND RWI. Outlook: This area of high pressure is expected to maintain its influence over our region through early next week. A weak backdoor cold front early Saturday will be followed by a northeast wind that could lead to some sub-VFR ceilings across the coastal plain on Sunday morning. Otherwise, VFR conditions are expected to prevail. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BS NEAR TERM...BS SHORT TERM...BS LONG TERM...RE AVIATION...BS

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