Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 271416 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 1010 AM EDT Mon Mar 27 2017 .SYNOPSIS... A warm moist southerly flow will hold over the area through Wednesday. An upper level trough will cross the region beginning late tonight through Tuesday, bringing unsettled weather. A backdoor cold front will drop southward through the area late Wednesday through Wednesday night. Another storm system will cross the area Thursday night and Friday. && .NEAR TERM /THROUGH TONIGHT/... As of 1010 AM Monday... The band of light showers was slowly weakening and dissipating over the eastern Piedmont and northern Coastal Plain late morning. Rainfall this morning has been generally less than a tenth of an inch with this band. We will update the weather and POP grids to indicate scattered showers closer to the Interstate 95 corridor with a few isolated showers possible over the western Piedmont through around 18Z. This afternoon, it appears that a lull in showers will occur, supported by current data and by the Hi-Res convection allowing models, as the focus for storms will shift well to our west over the Tennessee Valley with the next short wave trough. This trough will set off strong to severe thunderstorms over TN/AL this afternoon and evening with weakening storms likely advancing into the NC mountains tonight. Before that time, a few showers/isolated thunderstorms may develop this afternoon - with a low chance POP warranted into the Triad region. Satellite data indicated some breaks developing over much of the Piedmont, with stratus confined to the NW Piedmont and Foothills. This is expected to burn off by early afternoon. Partly sunny skies will lead to increased mixing with SSW winds 10-15 mph. Highs should warm into the 70s to near 80 in the Sandhills. Readings in the N and E Piedmont and N Coastal Plain may be tempered a few degrees due to the slower clearing. Tonight, increasing POP later over the western third of the region with the convective threat increasing. Otherwise, very mild SW flow and at least partly cloudy skies will lead to lows around 60 (15-20 degrees above normal). && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 330 AM Monday... Tuesday and Tuesday night low pressure currently over the Arklatex area will track north of the area through the mid-Atlantic states and bring a very weak cool front with it. Maybe a bit better chance for thunder Tuesday afternoon, especially in the central and eastern portions of the forecast area as instability look a little better than on Monday afternoon and low-level lapse rates remain very steep. The proximity of the low to the north will provide upwards of 25-30 kts of bulk shear to work with. As a result SPC, currently has the forecast area in a marginal risk for severe thunderstorms. While damaging wind should remain the primary threat, some better CAPE values aloft could result in some small hail. Temperatures will continue to be in the upper 70 to low 80s across the forecast area on Tuesday afternoon with lows in the mid 50s. && .LONG TERM /Wednesday through Sunday/... As of 205 AM Monday... Wed-Thu: Behind the departing shortwave through, the mid level ridge axis will shift eastward over the Southeast through Thu, although by Thu it will be deamplifying as the next mid level low tracks through the central CONUS. NC will remain in the warm sector for much of Wed, as the backdoor front holds to our north until late in the day, when energy dropping into the polar low SE of the Canadian Maritimes helps drive the cool dense surface high pressure area southward into NC, with the front dropping through NC NNE to SSW Wed evening/night and settling south of the forecast area by Thu morning. Expect partly to mostly sunny skies Wed with flat cumulus beneath the warm layer focused around 700 mb. The low levels will cool/stabilize Wed night with increased moisture pooling around 900-800 mb, so expect cloudy skies, thickest in the west where moist isentropic upglide will be deepest. While a uniform northeasterly low level flow into the area will set up behind the front, the 850 mb anticyclone will shift off the Carolina coast, resulting in increasing 850 mb winds and strengthening moist overrunning atop the cool stable pool Thu, most evident over the NW CWA. Will keep skies mostly cloudy to cloudy with a chance of light rain or drizzle in the W from late Wed night through Thu. Highs Wed from lower 70s NE to around 80 SW. Lows 45-55 NE-SW Wed night as cooler air pushes into the NE. Highs Thu from mid 50s NW to the mid 60s SE within a wedge regime. Thu night through Fri night: A volatile period as another strong mid level shortwave moves from the central Plains through the Miss Valley and Ohio Valley before crossing the Mid Atlantic region. At the surface, models depict the primary surface low tracking NE over or just south of SE MI through Fri, while the front to our south shifts back northward as a warm front, and a triple-point low forms over SW VA. While we would normally be skeptical about the complete passage of a warm front through NC immediately following a wedge regime, the parent high is rather weak and progressive and may be unlikely to put up much of a fight, so will depict a northward surge of higher dewpoints through much of the forecast area (excluding the far NW) on Fri. The primary low will then track up the St. Lawrence Valley Fri night while filling, as the triple-point low crosses WV and N VA and becomes the primary low near or just off the Delmarva peninsula, with W-to-E cold frontal passage through central NC. In terms of sensible weather, given the improving mechanisms to force ascent including mid level DPVA, strengthening upper divergence, and increasing 850 mb moisture transport, expect numerous showers and thunderstorms starting Thu night, peaking in coverage and intensity Fri, then exiting to our east Fri night as the mid level trough moves off the coast. A few strong storms are possible Fri, although the DPVA will have weakened a bit by the time the trough gets here, and we`re lacking the instability and strong kinematics that might prompt greater concern. Lows Thu night mid 40s to low 50s, highs Fri 62-72, and lows Fri night 49-55. Sat-Sun: Weak modified surface high pressure builds in behind the front with another rough of shortwave ridging in the wake of Friday`s trough and ahead of the next system moving from the Four Corners into the S Plains. Expect dry weather and partly cloudy to mostly clear skies. Thicknesses are projected to stay a bit above normal through the weekend, so expect highs from around 70 to the mid 70s. -GIH && .AVIATION /15Z MONDAY THROUGH FRIDAY/... As of 1010 AM Monday... 24 Hour TAF Period: Generally VFR CIGS expected this afternoon, with MVFR CIGS and VSBYS with showers/isolated thunderstorms expected to spread eastward into the region after 06Z/tonight. Lower IFR CIGS with showers likely between 06Z-12z/Tue, especially at KINT/KGSO/KRDU. This should spread into the KFAY and KRWI areas Tuesday. A return to VFR conditions is expected Tuesday night and Wednesday, with the exception of IFR to LIFR fog and stratus potential during the early morning Wed. Long term: A storm system is expected to push into the region Thursday night and Friday with showers, low CIGS, and fog. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...Badgett SHORT TERM...Ellis LONG TERM...Hartfield AVIATION...Badgett

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