Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 231050 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 650 AM EDT Mon May 23 2016 .SYNOPSIS...An upper level low will move across the area today, before tracking along the East Coast and away from the region on Tuesday. A strong upper level ridge will then build over the Southeast through the remainder of the week. && .NEAR TERM /through tonight/... As of 335 AM Monday... An upper level low centered over south-central VA will continue to move southeast over eastern NC this morning and then quickly offshore today. The last in a series of disturbances rounding the upper low is currently over eastern KY and will swing across th Carolinas today. Some convection will be possible again, with higher probability in the northern Coastal Plain as a slug of deeper moisture drops south out of VA this morning, before height rises strengthen in earnest behind the departing low this evening. Despite moderately steep mid-level lapse rates of 6.5-7 C/km within the upper low, instability is projected to be weak, especially int he northeast CWA given cloud cover and limited heating. Deep layer shear will generally be weak within the upper low, but 20-30kt around the southern/western fringe of the CWA could support an isolated strong storm capable of producing hail with the freezing level down below 8k ft. Highs are expected to range from the mid/upper 60s east, where clouds and the 850mb thermal trough will have the most impact, to the lower 70s in the west. Height rise aloft and high pressure building in from the west will rapidly diminish precip coverage this evening, while skies slowly clear behind the departing upper trough. lows in the low/mid 50s. && .SHORT TERM /Tuesday and Tuesday Night/... As of 340 AM Monday... While the center of the mid/upper-level low will be in the process of lifting up the coast of the northern Middle Atlantic and Northeast...a couple of low amplitude impulses are forecast to wrap, in NW flow on the WSW periphery of the departing low, across eastern VA/NC through early-mid afternoon Tue. Residually steep mid-level lapse rates /6 to 6.5 C/KM/ over the NE Piedmont and Coastal Plain, and diurnal heating into the lower 80s, will contribute to perhaps a couple of hundred J/KG of MLCAPE there, where an isolated shower/sprinkle (POP of only 10-15 %) may occur before following strong height rises aloft and an associated subsidence inversion overspread the region. One more night in the 50s, to around 60 degrees, is expected in continued height rises in NW flow aloft Tue night. && .LONG TERM /Wednesday through Sunday/... As of 355 AM Monday... Increasingly hot, but mainly dry. Within a relatively highly amplified flow pattern consisting of a western CONUS trough and eastern CONUS ridge, a couple of low amplitude southern stream perturbations will migrate across the Middle Atlantic late Wed-Fri. These perturbations will get trapped and stretched in a deformation zone aloft between the center of a couple of sub-tropical highs over Mexico and offshore the SE U.S coast, and may contribute to the development of diurnal convection across the Appalachians and/or along the sea breeze in coastal areas during that time. While an associated shower or storm cannot entirely be ruled out even over central NC, a lack of any more appreciable focusing mechanism suggests that probability will be low. Temperatures will climb into the upper 80s to around 90 degrees mid-late week, with perhaps slightly cooler conditions owing to a slightly onshore component to the low level flow, this weekend. && .AVIATION /12Z Monday through Friday/...
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As of 650 AM Monday... The main aviation concern today is an area of low clouds moving south out of VA early this morning, which will impact areas east of KRDU through at least mid-morning. MVFR ceilings are most likely at KRWI, with a period of IFR and scattered showers possible. Showers will be more isolated to the west, especially west of KRDU, where cloud bases are more likely to be in the 3000-4000ft range. An 8- 12kt northerly wind will prevail for much of the day, becoming light and variable tonight as low pressure moves off the NC coast and VFR conditions return areawide. Long term: VFR conditions will be predominate this week as high pressure builds over the region.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...22 NEAR TERM...22 SHORT TERM...26 LONG TERM...26 AVIATION...22

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