Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 231142 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 742 AM EDT Sun Jul 23 2017 .SYNOPSIS... Hot high pressure will remain across the mid-South and southern Appalachians through today, then gradually weaken by early next week. && .NEAR TERM /THROUGH SUNDAY NIGHT/... As of 320 AM Sunday... Dangerously hot conditions will continue across central NC through this evening. The surface trough will persist over the region on Sunday. The upper level trough over the Northeast U.S. will begin to amplify throughout the day. Meanwhile, a shortwave low will dive southeast out of Canada and through the Great Lakes within the upper level trough through tonight. Continued strong southwesterly flow will result in temperatures again in the 95-100 range for Sunday, although if convection gets going early in the afternoon it could dampen temperatures a bit. Regardless, expect the combination of heat and humidity to result in heat indices around 105 in the northeast and in the 109-112 range across the southeast. Overnight lows won`t be much relief, bottoming out at a balmy 73 to 77 degrees. The most recent convection allowing models suggest the weather will stay dry through mid morning across much of central NC. Showers and thunderstorms will ramp up quickly during the afternoon, mainly along and southeast of US-1, though a secondary band could develop in the west later in the aft/eve. Shear will remain relatively weak in the south and east where the instability is maximized, though MLCAPE values are around 1500 J/Kg, give or take 500 J/Kg. PWATs in that region will remain around 2.00" and as a result expect heavy rainfall with the storms that develop, with isolated strong winds. Another round of convection could move into the region from the northwest Sunday night as the upper level disturbance encroaches on the region. However, the unfavorable diurnal timing could limit convective development and intensity. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... As of 330 AM Sunday... The upper level trough will remain over the region through Monday night, as will the surface trough. The difference will be more cloud cover expected over the region, resulting in high temps slightly lower than previous days. Highs in the low to mid 90s expected, resulting in heat indices of 95-102. Lows still expected to be in the low to mid 70s. Expect more showers and thunderstorms Monday aft/eve, better chances in the south and east, decreasing overnight. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 310 AM SUNDAY... On Tuesday the upper trough begins to lift out to the northeast as surface high pressure resides over the great lakes. The residual frontal boundary will still remain over the southern part of the state and the Piedmont trough will remain active through the week as diurnal showers and thunderstorms will be prevalent through much if not all of the period. Several weak disturbances will periodically propagate along the frontal boundary providing some extra forcing for ascent. The most notable of these will be Tuesday night into Wednesday which could increase chances for rain overnight. Late in the week a second frontal system will push down from the northwest and will affect the area by next weekend. Expect high temperatures in the upper 80s to lower 90s with lows in the low 70s. && .AVIATION /12Z SUNDAY THROUGH FRIDAY/... As of 740 AM Sunday... 24-Hour TAF period: Expect mainly VFR conditions through the TAF period. The exception will be where storms develop late this afternoon and evening. Best chances for convection and the associated increase in winds and decrease in cigs and visbys may begin around 18Z at KFAY, however the models have backed off a bit and restrict most convective activity to the NC/VA border region after 21Z. Have kept the PROB30 mention of such in at KINT, KGSO, KRDU, and KRWI for this issuance. Some low stratus may develop toward daybreak Monday, however chances and confidence in sub-vfr cigs is low at this time. Looking ahead: Mainly VFR conditions expected through Tuesday, with the primary sub-VFR risk coming courtesy of showers and storms that will grow in coverage each successive day through Tue. Chances for early morning stratus increase Wednesday through Friday, but otherwise expect VFR conditions to prevail. && .CLIMATE... RDU Records: Date | High Year | High Min Year ------------------------------------------ 23 July | 105 1952 | 78 2011 24 July | 101 2011 | 79 2011 GSO Records: Date | High Year | High Min Year ------------------------------------------ 23 July | 99 1952 | 78 2010 24 July | 99 1914 | 78 2010 FAY Records: Date | High Year | High Min Year ------------------------------------------- 23 July | 103 2011 | 79 1998 24 July | 105 1952 | 79 1945 && .RAH WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 7 PM EDT Sunday for NCZ010-011- 026>028-041>043-077-078-085-086-088-089. Heat Advisory until 7 PM EDT Sunday for NCZ007>009-021>025- 038>040-073>076-083-084. && $$ SYNOPSIS...BADGETT/MWS NEAR TERM...KC SHORT TERM...KC LONG TERM...Ellis AVIATION...KC CLIMATE...RAH is the U.S. government's official web portal to all federal, state and local government web resources and services.