Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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545 FXUS62 KRAH 200630 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 230 AM EDT Wed Sep 20 2017 .SYNOPSIS... A weak upper level trough will move into central NC later today, then drift sewd through Thursday. Otherwise, an upper level high over the Ohio Valley and Tropical Cyclone Jose meandering off the southern New England coast will result in warm and dry conditions across central NC through the rest of the week. && .NEAR TERM /TONIGHT/... As of 925 PM Tuesday... Quiet weather as central NC sits between Hurricane Jose which is spinning off of the Delmarva Peninsula this evening and a short wave moving through eastern TN and northern GA. Calm winds and clear skies will prevail overnight with some MVFR fog possible across the north and possibly at KRWI. Overnight lows will be in the middle 60s with a few lower 60s possible due to the great radiational cooling conditions. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 307 PM Tuesday... A weak shortwave upper trough, comprised of several individual shortwaves that currently extend from the Ohio Valley SW into the Middle/Lower MS Valley will progress slowly ESE, moving into Central NC Wednesday afternoon and evening, before stalling out near the NC/SC late Wednesday night and Thursday. Limited by the lack of support/lift in the low-levels and the deep NWLY flow preceding the trough, convective coverage should be no greater than isolated to widely scattered Wednesday afternoon and evening, and largely driven by daytime heating. Weak deep layer shear of 10 kts or less coupled with MLCAPE values of 700 to 1500 MLCAPE will keep any convection sub-severe. The real story on Wednesday will be the return of near to 90 degree heat across central and southern portions of the state as low-level thicknesses and H8 temps increase to 1420-1425 meters and 17-18 C respectively. This should support highs a full category warmer than today, with highs ranging 85 to 90. Lows in the mid to upper 60s. && .LONG TERM /FRIDAY THROUGH TUESDAY/...
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As of 230 AM Wednesday... Central NC will generally be under the influence of high pressure through much of the extended forecast period, resulting in a predominantly dry forecast. However, a weak trough over the region could result in some showers on Friday, primarily in the southwest, but chances are no more than slight. Also, expect skies to be mostly sunny/partly cloudy through the weekend with highs in the mid to upper 80s and lows in the low to mid 60s. The forecast for Sunday onward remains somewhat uncertain, but the medium-range models are starting to trend closer to one another. The forecast will still depend on the track of Maria, which will depend on what happens with Jose. As a result, still have below average confidence in the forecast for Monday and Tuesday. Jose is still progged to meander off the NE U.S. coast through the weekend. Meanwhile, Maria will be moving through the Caribbean, northwestward toward the CONUS. As mentioned above, Maria`s impacts from Sunday onward are still highly uncertain as they will depend heavily on Jose and if/how the two systems interact with one another. For now, expect increasing cloud cover across eastern portions of Central NC Monday and Tuesday. Depending on if Jose comes back inland over VA and how close Maria gets to the NC coast will determine the strength of the winds and chances for convection Monday and Tuesday. Too much uncertainty still exists to speculate on either at this time.
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&& .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... As of 210 AM Wednesday... VFR parameters are generally expected across central NC through Sunday with a few exceptions. Early this morning, pockets of MVFR visibility are probable through 13Z. After 18Z, a few showers and an isolated thunderstorm may develop as an upper disturbance approaches from the west. The threat for scattered convection will persist into the evening hours, primarily in vicinity of KFAY. In proximity of the heavier showers and storms, expect brief instances of MVFR ceilings and visibilities. On Thursday, there is a small threat for a shower or storm near or south of KFAY. Otherwise VFR parameters should persist at the TAF sites Thursday through the weekend. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...ELLIS SHORT TERM...CBL LONG TERM...KC AVIATION...WSS

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