Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 261931 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 330 PM EDT TUE JUL 26 2016 .Synopsis... Strong high pressure aloft will extend over the Southeast U.S. through the work week, as weak disturbances pass by just north of the region. A cold front will approach from the northwest on Friday, then stall out just to our north and west next weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 330 PM Tuesday... Scattered showers and storms have already begun to fire over the mountains, foothills, and into the northern and western Piedmont, where CINH has vanished and MLCAPE has already risen well over 2000 J/kg. Deep layer bulk shear still isn`t great but is better than in the last several days, as shortwave energy tracks eastward across the OH valley and mid-Atlantic, nudging the westerlies slightly to the south and inducing sufficient acceleration aloft to boost values to around 20 kts across northern NC this evening. Have retained isolated to scattered showers and storms through the evening, starting first over the Piedmont (better coverage north and fewer storms south), then shifting eastward into the NE Piedmont and northern/central Coastal Plain through the evening before weakening and dissipating with loss of heating overnight. This scenario is supported by the latest CAM runs. A few storms could become strong, given the degree of instability, improving wind field aloft, and high downdraft CAPE over 1000 J/kg, but the mid level lapse rates remain meager with no good low level mass convergence, so widespread strong storms aren`t expected. Persistence will be followed for lows tonight, in the lower to mid 70s. Temps over much of the CWA won`t drop below 80 until well after midnight, exacerbating the adverse health effects of this ongoing hot spell. -GIH && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 325 AM TUESDAY... Persistent mid/upper level ridge located just to the south/southeast of central NC will continue to provide the region with hot and humid conditions with another day of highs in the mid to upper 90s and heat index values in the 100-107 degree range (highest east and south again). Thus, another heat advisory will likely be needed again on Wednesday afternoon/evening. With a similar pattern to today, we will again see the best chance of scattered showers and storms across the northern half of the area, with less across the south (closer to the center of the ridge). Deep layer shear is a bit stronger with around 20-25 KTS of 500 MB westerly flow. Thus, think we could see a few more clusters of storms across northern portions of the area. In addition a weak cold front will stall across southern VA on Wednesday afternoon, helping to increase coverage near the VA/NC border as well. More of the same is expected on Wednesday night, with warm lows in the mid to upper 70s and generally dry conditions. However, as will be the case tonight, we can`t completely rule out isolated showers/storms associated with possible weak disturbance(s) tracking across northern portions of the area. Confidence is too low to include any mention of precip in the forecast at this time though. && .LONG TERM /Thursday through Tuesday/... As of 230 PM Tuesday... Beginning Thursday, the high pressure system gets suppressed ever so slightly to the southeast and allows the remnants of the frontal boundary over VA to creep southward, increasing pops a bit for the northern tier of the CWA but otherwise points south should remain fairly dry but afternoon showers and thunderstorms will be favorable east of the Piedmont trough. Thursday night a wave is expected to develop just north of the area and move northeastward leaving Friday fairly dry. Afternoon convection will be possible again Friday and Saturday afternoons as the upper level flow turns more southwesterly. By Sunday, central NC becomes increasingly squeezed between a surface high to our southeast and another to our northwest. This will set up a more active pattern over the area which will funnel moisture into the area. This should help keep skies cloudier and bring temps down a few degrees for the beginning of next week. Early next week an upper trough develops to help push the frontal boundary through the area and hopefully provide some relief to temperatures. Until then expect continued highs in the mid 90s with heat index values approaching 105 degrees. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... As of 100 PM Tuesday... VFR conditions are likely to dominate through Wed afternoon, although scattered storms may produce localized enhanced wind gusts and brief sub-VFR conditions late today through this evening, mainly at INT/GSO/RDU/RWI. Strong, dry, and deep ridge of high pressure in the middle and upper levels of the atmosphere will hold overhead for the 24 hours and beyond. Any cloudiness will be VFR, mostly scattered except for a period of broken clouds late today into tonight at INT/GSO/RDU/RWI, as well as in/near any storms. Light fog (MVFR) is possible late tonight into Wed morning, mainly at RWI/FAY, and isolated banks of shallow, more dense fog may occur, mainly near RWI. The overall threat of sub-VFR fog is low, but places that see a shower or storm later today will have a better chance of seeing fog late tonight into Wed morning. Surface winds will be light from the southwest at 6-10 kts through Wed. Looking beyond 18z Wed: Mostly VFR conditions are anticipated, although late night and early morning MVFR fog is possible each day through Fri, with a better chance of sub-VFR fog/stratus Sat/Sun. Scattered showers/storms are again expected Wed afternoon, mainly at the northern TAF sites. Storm chances will drop once again for Thu and Fri, before rising again over the weekend. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... Heat Advisory from noon today to 8 PM EDT this evening for NCZ007>011-024>028-040>043-074>078-083>086-088-089. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM...BSD LONG TERM...Ellis AVIATION...Hartfield

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