Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 240253 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 750 PM EST Thu Nov 23 2017 .SYNOPSIS... High pressure extending from the Chesapeake Bay southwest to the lower Mississippi Valley tonight will persist across the region through early Saturday. A dry cold front will move through the region late Saturday with high pressure building back into the region for Sunday and early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 750 PM Thursday... Latest surface analysis shows high pressure centered near the Hampton Roads area of VA with a surface low east of Jacksonville FL. Water vapor imagery shows a slowing eastward translating upper-level trough extending near and just east of the Appalachians with a plume of high level clouds zipping northeast. The western edge of this cloud shield is edging east very slowly east this evening. Current forecast is in good shape. Fair weather and dry conditions are expected overnight. Have made some minor adjustments to hourly sky, temp and dew point grids but nothing too significant. -Blaes Previous forecast from 218 PM Thursday... A short wave trough with embedded sheared vort max is lifting NE along the SE states coastal region. A shield of mainly light rain along and ahead of this disturbance is ongoing across coastal sections of GA and SC. It is slowly lifting NE, but according to the latest mesoanalysis...is running into much drier air located north of the SC/NC boundary and thus is making very slow progress NEWD as the northern edge is drying up in the process. Nevertheless, the latest HRRR shows that eventually this light rain shield will lift into coastal sections of NC as the atmos there eventually moistens enough to allow very light rain to reach the ground there. While earlier runs of the HRRR showed that the NW edge of the rain could get into southern Sampson Co, the latest runs and most recent mesoanalysis moisture fields suggests otherwise. So for now, will keep rain out of our SE zones and will monitor closely. Farther west, it`s just a matter of cirrus and how much of it, and it`s effects on temps tonight. The thickest cirrus, now along and east of the I-95 corridor, is expected to remain east of I-95 and gradually shift east of there overnight as the aforementioned short wave trough axis shifts east. Otherwise, at the sfc, high pressure now centered to our north over VA will continue building southward, becoming centered over NC by 12Z Friday. Consequently, winds should go calm across our entire CWA after midnight, and when combined with clearing skies, will set up good radiational cooling conditions overnight. Latest sfc dwpts and low level thickness, when combined with radiational cooling, suggest lows in the upper 20s to lower 30s. Chilly temps for those venturing out tonight or early Friday morning! && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... As of 218 PM Thursday... High pressure and a dry airmass with westerly flow aloft and a seasonable airmass is the weather story for Friday. Look for plenty of sunshine during the day Friday with highs in the upper 50s to around 60. Friday night, the next short wave embedded in the longwave trough over the East will be crossing the Ohio Valley. While it`s assoc cold frontal passage won`t occur until late Saturday, we will see an increase in high clouds Friday night in advance of it. Thus with these high clouds, low temps Friday night should be a little warmer than tonight`s lows. Low temps Friday night in the mid 30s, under increasing high clouds. && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 150 PM EDT Thursday... Little change in longer range forecast. A mild day is in store for Saturday with a westerly flow ahead of an advancing, rather dry, cold front. Next area of high pressure will settle over the region Sunday through the middle of next week. The cooler temperatures behind the cold front Sunday and Monday will be rather short-lived as the upper ridge over the Western US transitions eastward atop the Eastern US by Tuesday/Wednesday. Highs Sunday and Monday in the low to mid 50s north to upper 50s south, then warming back up into the 60s and possibly even near 70 across the southern coastal plain and Sandhills by Wednesday. Model spread increases Wednesday and Thursday with the timing of upper trough ejecting out of the Rockies into the southeastern US. It still does not appear that this system will produce significant rainfall across the Carolina region. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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As of 715 PM Thursday... 24 Hour TAF Period: VFR conditions are expected to continue for the 24 hour TAF period. Surface high pressure will build into and settle over the area tonight into Friday. Meanwhile, high level moisture moisture over the eastern half of the area will shift to the east this evening as a slow moving mid level trough axis shifts eastward and over the area. Otherwise, skies will remain clear/mostly clear with generally light and variable winds. Outlook: A cold front will move across the region late Saturday and may bring a brief period of sub-VFR conditions during that time. Otherwise, VFR conditions expected through Tuesday.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Blaes NEAR TERM...Blaes SHORT TERM...Blaes/np LONG TERM...CBL/Franklin AVIATION...bsd/np

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