Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 220038 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 838 PM EDT SUN AUG 21 2016 .SYNOPSIS...
-- Changed Discussion --
A cold front will progress east through our area tonight. In the wake of the front, dry high pressure will build into the region from the west through mid-week.
-- End Changed Discussion --
&& .NEAR TERM /TONIGHT/... As of 320 PM Sunday... An upper level trough progressing east through the Great Lakes today and into New England tonight will push a seasonably strong cold front across the area late this evening and overnight. Westerly flow aloft preceding the front and late unfavorable diurnal timing will limit convective pops/coverage across the area with the the highest pops expected over the NW Piedmont and northern Piedmont during the 21z-01z, with rapid weakening thereafter owing to boundary layer cooling/stabilization. There is a small and narrow window for strong to severe storms across Central NC, confined primarily north of Highway 64 and west of the Triangle, between the hours of 3pm to 8 pm. Along the southern fringes of the westerlies, 30kts of shear combined with moderate instability ~1000 to 1200 J/Kg of MLCAPE could support an isolated potential for damaging winds (aided by precip loading and downward momentum transport) and marginally severe hail. Expect convection to end from west-east between 03 to 06z as the surface front /low-level trough/ progress toward the Carolina coast. CAA in the wake of the front will drive overnight lows with temps falling into the mid to upper 60s over the Piedmont and lower 70s across the Sandhills and Coastal Plain. For many places across the area, tonight will be the first time in 4 to 6 weeks in which temps fall below 70 degrees. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... As of 320 PM Sunday... Parent high center over the Middle MS valley will strengthen as it builds eastward into the Mid-Atlantic States Monday-Monday night as heights increase aloft under quasi-zonal flow aloft. While daytime temperatures will only be slightly below normal, nwly flow will advect considerably drier air into the regional with PWATS well below normal, between 0.6-0.75", and bl dewpoints falling into the 50s. Capped aloft by the warm temperatures aloft a stable and dry airmass will yield mostly sunny/clear skies with strong radiational cooling will support some of the coolest temperatures we`ve since early June. Highs in the 84 to 89. Lows in the upper 50 north to lower/mid 60s south. && .LONG TERM /TUESDAY THROUGH SUNDAY/... As of 320 PM Sunday... Surface high pressure over the Mid Atlantic states on Tuesday will move off the east coast on Wednesday. Upper level ridging will build over the Southeast from Wednesday through the end of the week, leading to increasing temperatures, with highs in the low 90s by Thursday. Shortwave energy moving along the Canadian border Thursday and Friday will bring a cold front in to the the Mid Atlantic, but with most of the energy lifting northwestward the front will weaken considerably and seems unlikely to make a push in to central NC. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
As of 830 PM Sunday... Showers and storms have kicked east of RWI and FAY as of 00z, leaving areas to the west in VFR conditions. A cold front moving into the mountains will cross the area after 06Z, and some patchy fog/stratus seems plausible ahead of the front and arrival of lower dewpoints, despite little support from model guidance. Northwest winds will, however, bring that drier air and prevailing VFR on Monday as high pressure builds over the region. Outlook: VFR conditions and light winds will prevail through mid- week as dry high pressure builds eastward from the OH Valley into the Mid-Atlantic.
-- End Changed Discussion --
&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BS NEAR TERM...CBL SHORT TERM...CBL LONG TERM...SEC AVIATION...CBL/BS

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.