Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 170812 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 411 AM EDT Mon Jul 17 2017 .SYNOPSIS...
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A weak cold front will gradually dissipate today. High pressure aloft will build east from the Plains states Tuesday through Friday, leading to increasingly hot and humid weather.
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&& .NEAR TERM /TODAY AND TONIGHT/...
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As of 410 AM Monday... The stalled shear axis on the lee of an amplifying trof will produce a wide range of both temperature and PoPs today. Convection will become more widespread in the east this morning as an upper short wave lifts up the coastal plain where moisture is deepest (PW`s ~2 inches) and will bump the PoPs in the southern coastal plain to the 60% range. Coverage will be maximized through early afternoon, with scattered storms redeveloping through evening due to mesoscale forcing from earlier outflow boundaries. Meanwhile, forcing will be weaker with dry mid levels (PW`s of ~1 inch) in the northwest piedmont and will maintain ongoing 20-30 PoPs. Temps will be hampered by cloudiness and precip in the southeast, and highs will stall in the mid 80s, while plentiful sun will allow the northwest to reach upper 80s. Activity will wane early tonight with loss of diurnal heating, and a second short wave will be digging into the upper trof...nudging the deeper moisture plume east of the area by late day. As such, PoPs will be falling off over all but the far southeast counties after midnight. Mins will be persistence...within a degree or two either side of 70.
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&& .SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
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As of 410 AM EDT Monday... Surface and mid level troffing will be slow to exit the Atlantic coast, but some reduction in cloudiness due to mid level drying in the east will allow highs to reach very low 90s. Convectin will be less widespread, being diurnally driven and leaning a little more numerous in the southeast where residual moisture will be more available. Isolated showers could persist into Tuesday night, with mins again around 70.
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&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 400 AM Monday... A pair of shortwave troughs evident in WV imagery over wrn NC and central IN this morning will contribute to the development of a mid- upper low over the middle Atlantic states during the next 24-48 hours, which will move slowly east and off the middle Atlantic coast by 00Z Thu. Meanwhile, an upper ridge now over the central Plains will strengthen and expand/build esewd across the middle MS and TN Valleys through the weekend. Central NC will consequently lie on the far srn fringe of a belt of initially nwly flow aloft that will gradually back to wly, as the ridge becomes situated over the southeastern U.S. by Sun. At the surface, a trough will become established in the lee of the srn and central Appalachians, on the wrn periphery of high pressure over the central and wrn N. Atlantic. Meanwhile, a frontal zone will settle swd, into VA by Fri night-Sat, before retreating nwd by Sun- Sun night. This frontal zone may become briefly modulated swd into nrn NC by convective outflow Fri night-Sat; and precipitation chances will be maximized (in the chance range) then and there. Otherwise and elsewhere, the presence and influence of the sub- tropical ridge will likely restrict diurnal convection to differential heating zones over the mountains and along the sea breeze. The bigger story will likely become another round of heat and high heat indices, as temperatures beneath the ridge climb into the middle 90s to around 100 degrees - hottest Fri-Sat. When combined with surface dewpoints ranging from the middle to upper 60s west of the Appalachian-lee trough (over the nw NC piedmont) to lower to middle 70s to the east of that feature (over the Coastal Plain) heat index values between 100 and 110 degrees are expected to result. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... As of 140 AM Monday... 24 hour TAF period: Widely scattered light showers continue to pop up periodically in the moisture laden airmass over the area. Coverage is too sparse to include as a prevailing or tempo group outside of FAY where coverage will be enhanced by a mid level wave lifing up the coastal plain this morning. Predawn MVFR fog and perhaps some stratus is expected with humidities at 100% with light southerly flow, with improvement by 13Z except perhaps at FAY where MVFR ceilings are possible through mid day. Diurnal convection on Monday will be mainly focused in the east...FAY & RWI. Long term: Diurnal showers and storms will be possible through midweek and along with that the possibility for fog/low stratus each morning through the period. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...mlm SHORT TERM...mlm LONG TERM...MWS AVIATION...mlm

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