Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 241942 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 340 PM EDT Mon Jul 24 2017 .SYNOPSIS... A surface trough will extend from central Virginia southwest into central North Carolin through tonight. A cold front will drop south into the region late tonight and on Tuesday. The front will stall across the Carolinas on Wednesday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 340 PM Monday... The latest surface analysis shows a surface trough extending southwest from the northern Chesapeake Bay into the Piedmont of NC. A cold front extends from southern New Jersey west to southern Ohio and then into western Kentucky. Further aloft, a moderate amplitude trough extends south from the eastern Great Lakes into the Carolinas with the last short wave trough sweeping across western VA and NC early this afternoon. The air mass across central NC continues to dry out from the northwest with precipitable water values now ranging from 1.3" near KGSO to around 1.8" near KFAY. The air mass has also cooled down with the 1000-850 MB thickness values about 20m lower than yesterday day at this time at KGSO and KRNK with less cooling, around 10m at KMHX. The radar this afternoon is rather quiet with fairly widespread convection across portions of GA and SC and scattered storms across parts of VA and WV associated with the cold front. Convection allowing models suggest storms will be isolated across central NC this afternoon and evening. GOES-16 visible satellite imagery shows some cumulus enhancements in the U.S. route 1 corridor, a few of these are apt to develop into showers and perhaps a few thunderstorms with the greatest storm threat across the southern Coastal Plain and Sandhills. Convection upstream in VA and WV are apt to weaken before reaching central NC. The atmosphere today is less unstable than previous days with afternoon MLCAPE values ranging between 800 and 1800 J/Kg range. Bulk shear values range between 15 and 20 kts. Storm coverage will be less than previous days with much weaker intensity. Skies should average partly cloudy overnight with lows similar or perhaps a degree or two cooler than previous nights, bottoming out in the 71 to 77 range. -Blaes
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&& .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 230 PM Monday... The main portion of the upper level trough across the Northeast and Mid Atlantic shifts east and lifts on Tuesday and Tuesday night while a shear axis lays down east-northeast to west-southwest from near Cape Hatteras to central GA. The latest GFS and EC both try to close off a portion of the shear axis over eastern GA and the SC coast. At the same time, the associated cold front drops south into NC on Tuesday afternoon and evening and then stalls toward the NC and SC border by daybreak Wednesday. This is a more aggressive and southward solution than recent model runs. This trend would tend to confine precipitation further south and east and could result in additional cooling across our northern tier with the possibility of a layering of additional stratus and then some clearing near the VA border. Not ready to jump all in on this solution, but have trended the forecast that way. Highs on Tuesday will range in the lower 90s but could be cooler near the VA border if the cooler air is aggressive. Lows Tuesday night will range in the 68 to 75 range. -Blaes && .LONG TERM /WEDNESDAY THROUGH SUNDAY/...
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As of 220 PM Monday... Surface high pressure over the northeastern CONUS will extend into the region on Wednesday as a frontal zone lingers south of the CWA. This will be our first break from 90 degree temperatures as highs are expected to be in the mid to upper 80s. This high will remain over the area on Thursday as well although max temperatures will climb into lower 90s. Although diurnal showers and a possible thunderstorm cannot be ruled out, these days should be fairly dry. By Friday, a developing low pressure system, spurred on by a shortwave upper trough, will cross the mid-Atlantic states and move off the coast. As it does so, an east-west oriented front will sag southward towards central NC. Timing in both the GFS and ECMWF solutions is fairly similar and it looks like enhanced precipitation will begin at some point Friday afternoon/evening and continue through the weekend. Highest chance for rain will lie across eastern areas Sunday and Monday. After a brief stint back in the 90s on Friday, temperatures will return to the mid to upper 80s through Monday.
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&& .AVIATION /18Z MONDAY THROUGH SATURDAY/... As of 210 PM Monday... 24-Hour TAF period... VFR conditions are expected to be common across central NC outside of some residual stratus in the Coastal Plain near the KFAY terminal early this afternoon, areas of morning stratus in the Coastal Plain on Tuesday morning, and local restrictions in an isolated shower or thunderstorm. isolated showers and storms will develop this afternoon and could persist into the evening, mainly across the Coastal Plain and Sandhills. West to southwest winds at 5 to 10kts will become light northerly after midnight. Looking ahead... Primarily VFR conditions are expected through much of the work week with scattered, mainly afternoon and evening showers and thunderstorms expected, especially toward the end of the period. Areas of late night and morning stratus can be expected, especially Thursday into Saturday. -Blaes && .EQUIPMENT... The KRAX WSR-88D will be down for the Service Life Extension Upgrade (SLEP) beginning this morning and likely lasting through Thursday or Friday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BLAES NEAR TERM...BLAES SHORT TERM...BLAES LONG TERM...RE/Franklin AVIATION...BLAES EQUIPMENT...BLAES

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