Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 290739 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 340 AM EDT Sat Apr 29 2017 .SYNOPSIS... A warm moist southerly flow will continue through the weekend, as a strong high pressure remains anchored off the Southeast U.S. coast. && .NEAR TERM /THROUGH TONIGHT/... As of 340 AM Saturday... It will definitely feel like summer today as central NC as an area of high pressure at the surface and aloft extends across our region. This abnormally strong high for this time of year will support high temps a solid 10-15 degrees above normal ranging from the upper 80s- lower 90s. The heating of the marginally moist and unstable air mass may trigger an isolated shower or storm in vicinity of the Yadkin/Pee Dee River Valley, though a mid level subsidence inversion will provide a decent cap to prevent convection from popping across the region. Another night of warm/muggy conditions anticipated tonight. Skies will start out mostly clear-partly cloudy though expect a deck of low clouds to overspread the region from the south late this evening into the overnight. Min temps upper 60s-near 70. && .SHORT TERM /Sunday and Sunday night/... As of 340 AM Saturday... Main adjustment to the Sunday-Sunday night period was to adjust max temps up a few degrees from the previous forecast. Finding it difficult to justify high temps as much as 7-8 degrees, primarily over the western Piedmont, Sunday afternoon with little notable change in the low level air mass. Surface and upper level ridge does weaken with upper heights 30-50m lower than today, but warm/moist sly flow will maintain the summer-like air mass. Morning clouds will slowly depart in the afternoon, which should allow for at least partial sun in the western Piedmont by mid afternoon. With temperatures starting out near 70, should see temps recover into the mid 80s across the west, upper 80s-near 90 in the east. Some weakening of the mid level subsidence inversion and slightly deeper moisture and instability will support isolated convection in the late afternoon-early evening across the western half of central NC. May see an uptick in isolated showers late Sunday night, mainly across the far west, as a s/w approaches from the southwest. This system will may enhance convective coverage on Monday. Continued warm and muggy with overnight temperatures once again in the 60s to near 70. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 330 AM Saturday... A shift in the longwave pattern next week will ultimately result in lower heights over the eastern US and a ridge over the west. The sub-tropical ridge over the Southeast this weekend will shift east Monday as a deep upper low lifts from the Southern Plains to the Great Lakes. The associated cold front and convective line will be crossing the mountains early Monday, encountering more favorable heating/instability in the west Monday afternoon before undergoing a general downward trend in intensity as it progresses east Monday night owing to a loss of better forcing and heating. Still expect PW over 1.5" and 60-80m height falls to support at least scattered showers through central NC Monday night before moving to the coast early Tuesday. Highs Monday in the upper 70s to mid 80s. Lows in the mid 50s to lower 60s. Temps will be knocked back top near normal briefly on Tuesday, but with the secondary polar front holding to the north across VA, temps will rebound into the mid 80s and above normal Wednesday. the next shortwave moving through the longwave trough is forecast to strongly amplify over the Deep South Thursday, with medium range guidance showing the potential for another cut off low near Tenn Thursday night. Models diverge quickly regarding out the eventual track of the low, but the pattern will favor widespread precip late Thursday and Friday, some of which could be heavy if the low slows and tracks closer to the Southern Ablutions. Temps are most likely to be below normal int he upper 60s and low/mid 70s. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... As of 120 AM Saturday... Low level southerly flow around an area of high pressure anchored offshore will advect moisture off the Atlantic overnight. This will spread a deck of low stratus northward across central NC, resulting in widespread IFR/LIFR ceilings across central NC. These ceilings will likely persist through 14Z-16Z, afterwhich ceilings will lift and dissipate with VFR parameters highly probable this afternoon- early evening. An isolated shower or storm cannot be ruled out across the western Piedmont, though probability of a shower or storm affecting the Triad terminals is too remote to mention in the TAF at this time. Another round of IFR/LIFR ceilings are highly probable late this evening through late morning Sunday. A few more isolated showers or storms are possible Sunday afternoon, primarily over the western Piedmont. IFR/LIFR ceilings are again likely late Sunday night through Monday morning. Scattered showers and an isolated thunderstorm and associated sub VFR ceilings/visibility are possible across central NC Monday afternoon into Monday night as a cold front approaches then crosses the region. VFR conditions appear likely Tuesday and Wednesday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS LONG TERM...Smith AVIATION...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.