Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 200646 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 240 AM EDT Tue Jun 20 2017 .SYNOPSIS... A cold front will track east across the mountains this evening, then stall over the Carolinas tonight. The front will gradually dissipate over the region on Tuesday. && .NEAR TERM /Today and Tonight/... As of 1010 PM Monday... A lead cold front, and relatively deep convergence axis that extends through around 850 mb per proximity RAOB and regional VWP data, is roughly aligned with the wsw to ene-oriented band of training convection now over the nrn NC Piedmont. Low level moisture transport, analyzed to be strongest from the nrn NC Piedmont to the nrn Middle Atlantic coast per RAP/SPC-mesoanalysis 850 moisture transport data, is forecast to lift newd with a llj now traversing those areas through 06Z. Low level shear resulting from the presence of the llj --characterized by 0-1 km bulk shear values of 25-35 kt and effective SRH around 200 m2/s2-- will remain supportive of transient supercell/bowing structures along the convective line. However, the associated risk of severe wind gusts will likely remain limited due to the presence of weak mid level lapse rates of around 5.5 C/km or less and associated generally weak MLCape of aob 1500 J/KG - and associated limited updraft strength/depth. As such, heavy rain and a risk of flash flooding will instead pose the primary hazard overnight. && .SHORT TERM /Tuesday and Tuesday night/... As of 200 PM Monday... The cold front progressing into the region late this evening is expected to stall over central NC tonight and persist during the day Tue, amidst broad cyclonic flow aloft and rich moisture (PWAT ~2.00"). With the above in mind, expect numerous showers/storms in vicinity of the stalled front Tue/Tue night, primarily east of Hwy 1 and south of Hwy 64. Little potential for convection is expected north of the front in the far N/NW Piedmont near the VA border where a drier airmass (PWAT ~1.50" and dewpoints in the lower 60s) is progged to be in place during the day Tue. However, even in the northern Piedmont, isold to sct convection will be possible AOA ~00Z as the front washes out and moisture returns N/NW toward the Appalachians. With cloud cover and convection, expect highs in the lower 80s across most of central NC. Lows Tue night should range from the mid 60s far N/NW to lower 70s far S/SE. -Vincent && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... As of 147 AM EDT Tuesday... The chance of showers and thunderstorms will increase again Thursday as deep subtropical moisture surges northward again around the Bermuda surface high pressure. The influx of deep subtropical moisture will be aided by the remnants of the tropical disturbance that is forecast to get pulled NW into the western Gulf Coast states Thursday. A broad southerly flow from a wide open Gulf of Mexico will lead to PW`s increasing again to 2+ inches by Thursday and Friday, into the weekend and early next week. Convection should be largely diurnally driven, with likely POP during the afternoon and evening, then high chance POP`s overnight Thursday into Monday. Rainfall may be enhanced by a cold front that is expected to slowly move SE into the region Sunday into Monday. QPF of 2-4 inches is expected late week into the weekend into Monday. With the recent heavy rain over portions of the Triad, Triangle, and the Piedmont in general, a flooding threat may develop. Temperatures should be above normal given the very high dew points in the 70s, keeping nightly lows 70+ and possible 75 in the SE. Highs should be in the mid 80s NW ranging to lower 90s SE each day, with some cooling aided by the expected heavy rain and cloudiness early next week. && .AVIATION /06Z Tuesday through Saturday/...
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As of 240 AM Tuesday... A large area of convection extending from near Roanoke Rapids southwest through the Triangle to near Charlotte NC is associated with an approaching cold front. The showers and storms will slowly shift southeast through daybreak with reduced cigs and vsbys and an embedded thunderstorm or two. Expect cigs to fall into the MVFR and possibly IFR range by daybreak in most location with most of the convection dissipated by this time. Conditions will improve after sunrise with VFR conditions expected behind the front in the Triad today at the KINT and KGSO terminals. Near and southeast of the front, after a periof of VFR conditions this morning, scattered convection is expected to redevelop this around midday and this afternoon with the greatest coverage across the Sandhills and southern Coastal Plain near the KFAY terminal. Another round of low stratus is likely to develop late tonight. Looking beyond the 24 hour TAF period...a typical summertime regime is expected with perhaps greater than climatological coverage during the period. This pattern will feature scattered diurnal afternoon and evening convection with periods of early morning stratus. During the period it appears convective coverage will be more limited on Wednesday into Thursday and increase into the weekend. -Blaes
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Vincent NEAR TERM...MWS SHORT TERM...Vincent LONG TERM...Badgett AVIATION...Blaes

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