Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 252259 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 659 PM EDT MON JUL 25 2016 .Synopsis... Strong high pressure aloft will extend across the region through much of the work week, bringing continued hot and humid conditions to central NC. The chances for afternoon storms will increase by mid week. && .NEAR TERM /through tonight/... As of 305 PM Monday... Isolated storms along the Yadkin River valley and NW Piedmont are having a tough time staying alive as they face very warm and dry mid levels and very weak deep layer bulk shear. See little change in this regime over the next several hours, so any convection should be fairly short-lived, isolated, and not very strong. Otherwise, the surface dewpoints remain rather high across the area, still in the lower-mid 70s except around 70 in the Triad region, having not mixed out very much yet again today. As a result, heat indices have easily approached or exceeded 105 degrees over the advisory area. Expect a few more clouds this evening and tonight as compared to past nights, as upstream convective debris clouds drift into the area before dissipating. Expect muggy lows on par with last night`s lows, mainly in the mid 70s, which will afford no real relief from the heat. Isolated pockets of mostly light fog may form late tonight. -GIH && .SHORT TERM /Tuesday and Tuesday night/... As of 325 PM Monday... Shortwave energy over the central part of the country will push eastward into the OH valley toward the mid-Atlantic/Northeast through Tue night. While the primary bound of mid level westerlies will stay well to our north, this wave will help push both the surface frontal zone and the slightly deeper moisture (as noted on water vapor imagery) to the SSE toward NC, not quite reaching the NC/VA border but making enough southward progress to bring a scattered showers and storms to northern NC. Mid level lapse rates should be a bit better than today, in the 5.7-6.0 C/km range, although deep layer shear will remain miniscule as the mid-upper level ridge axis will continue to extend across the region. Model forecast CAPE values are expected to remain muted with the continued warmth aloft, particularly across the southern two-thirds of NC, closest to the ridge axis. Will bring in late-day low chance pops across the northern sections of the CWA Tue into early Tue evening, before coverage drops off through the evening with loss of heating. See little reason to depart from persistence regarding temps, with thicknesses remaining well above normal, topped by anomalously high temps and heights through the column, and high surface dewpoints holding at or above the low-mid 70s for a good portion of the day. Will retain highs in the mid-upper 90s, as statistical guidance supports, with lows again in the mid 70s. These temps again equate to heat indices near or above 105 over the south and east, so will go with another heat advisory for Tue for the same areas. These successive days of hot temps and high humidity without much recovery at night will exacerbate the risk of heat illnesses heading into mid week. -GIH && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 300 PM Monday... Stacked high pressure remains over the southeast for the middle part of the week bringing no relief to the oppressive heat that has been plaguing the area for the last several days. Heat indices will be near or above the 105 degree mark each afternoon across counties east of highway 1 and heat advisories will most likely be necessary. There will be a chance for some afternoon showers and thunderstorms especially in northern and western areas as the remnants of a frontal boundary will be across southern VA. Models differ for the end of the week regarding a low pressure system that the GFS develops over the mid-Atlantic states which could provide some opportunity for an increase in shower and thunderstorm activity, particularly across the north, but the ECMWF solution is far removed from our area and thus it remains drier. Models are are also indicating a drop in dewpoints for the weekend and into early next week which while the highs are still expected to be in the mid-90s the heat indices fall slightly below advisory criteria with with perhaps of only a high near 90 next Monday with a cold front on the doorstep to hopefully provide a break from the heat. && .AVIATION /00Z Tuesday through Saturday/... As of 700 pm Monday... 24-hr TAF Period: Aside from isolated convection that could potentially affect the RDU/GSO/INT terminals for a brief period of time prior to ~01Z this evening, in addition to a 1-2 period of IFR fog/stratus that may develop at the RWI terminal (persistence), there is high confidence that VFR conditions and light or variable winds will dominate the TAF period in association with an upper level ridge centered over the region. Looking ahead: High confidence in VFR conditions prevailing through mid-week as an upper level ridge remains in place over the southern CONUS. Diurnal convection will become increasingly possible as the ridge weakens /week progresses/, with chances near climatology by late week. -Vincent && .RAH WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM EDT this evening for NCZ007>011- 024>028-040>043-074>078-083>086-088-089. Heat Advisory from noon to 8 PM EDT Tuesday for NCZ007>011- 024>028-040>043-074>078-083>086-088-089. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...Ellis AVIATION...Vincent

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