Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 180835 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 335 AM EST Sun Feb 18 2018 .SYNOPSIS... A weak cold front will continue to cross our region this morning. High pressure will build into the area this afternoon, then quickly drift offshore later tonight. && .NEAR TERM /THROUGH TONIGHT/...
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As of 330 AM Sunday... GOES-16 1-minute infrared satellite imagery shows continued orographic enhancement along the back edge of the cloud cover. This is supported by the 00z observational soundings with a strong low level inversion and unidirectional flow out of the southwest increasing with height. While northwesterly would be the optimal flow for orographic enhancement, southwesterly flow cases are well documented and not unusual. Forecast soundings show extremely dry airmass aloft that will eventually penetrate to the surface and clear things out but that might not be until 15z or so. Until then expect low ceilings and reduced visibilities. Once clearing occurs expect winds to gradually swing around to northeasterly by this afternoon. Despite the northerly component to the winds most of the day, insolation will be plenty and temperatures will rise back into the upper 50s to mid 60s, quite a bit warmer than yesterday. After 00z this evening expect clouds to start filling back in from the southwest. Pops will begin to increase in association with another shortwave expected to move through early Monday morning with showers possible as it does. Lows in the 40s with lowest temps in the northeast.
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&& .SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
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As of 330 AM Sunday... After the shortwave moves out on Monday morning, central NC will enter an extended period of summer like conditions with a strong Bermuda high in place bringing southerly return flow and warm air advection to the area. While it may take a CAD wedge a little while to break down, southern locales will see high temperatures pushing the 70 degree mark by Monday afternoon. The airmass will be fairly moist with dewpoints in the upper 50s across the south. If the wedge scours out sooner, temperatures in the Triad could be underdone. As is the case with moist southerly return flow, pockets of showers will be possible throughout the day on monday but largely inconsequential. Lows Monday night will be quite a bit more moderate, only reaching the low to middle 50s.
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&& .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 257 AM Sunday... A 595 ridge centered off the SE coast and resulting warm southerly flow over our area will give us unseasonably warm conditions during the middle of the week, with perhaps some record highs. This ridge will flatten and shift south during the latter half of the week, which will allow a cold front to approach from the north (perhaps in backdoor fashion) on Thursday, dropping southward to roughly the I- 85 corridor. Thereafter, model solutions diverge regarding whether the front pushes all the way through our CWA on Friday per the GFS, or lifts back north early Friday per the ECMWF. Either way, it appears that low-end PoPs will be needed for at least the northern half of our CWA for late Wednesday through Thursday. Thereafter, if the front lifts back north on Fri per the ECMWF, that would result in a drier forecast for Fri and Sat. However, if it pushes through on Fri then lifts back north on Sat per the GFS, that would result in lingering rain chances both days. As for temps...There`s decent agreement in the guidance through at least Thursday with thickness profiles, which suggest highs in the upper 70s to around 80. Readings this warm would break some high temp records Tue, Wed, perhaps Thu. (see climate section below). Overnight lows in the 50s to around 60 will also come close to record warm lows. && .AVIATION /00Z SATURDAY THROUGH THURSDAY/... As of 633 PM Sunday... 24 Hour TAF Period: A line of showers has made it half way through the CWA this morning and will continue to move southeastward exiting the area by 8 or 9 z. Moderate showers at KRWI may also affect KFAY later but will move through quickly. Precipitation is over at KINT, KGSO, and KRDU and ceilings will clear out and followed by some brief patchy dense fog before much drier air moves into the area. After any fog lifts, the main story will be the wind direction as winds will gradually swing around to northeasterly by this afternoon. Some gusts to 15 kts will be possible, particularly in the south. MVFR ceilings may creep into the southern areas by the end of the TAF period. Long term: Another shortwave will move through Sunday night presenting a good chance of sub-VFR conditions and precipitation. A frontal zone will reside northwest of the area for much of the work week and could present some problems for aviation conditions in the Triad on Thursday before the front sinks south for next weekend. && .CLIMATE... RDU Records: Date | High Year | High Min Year ------------------------------------------ 02/20 75 1939 62 1939 02/21 76 2011 55 1939 02/22 75 1897 60 1897 02/23 79 1980 57 1962 02/24 81 1982 58 1985 GSO Records: Date | High Year | High Min Year ------------------------------------------ 02/20 74 1922 56 1939 02/21 74 2011 50 1954 02/22 74 1925 57 1980 02/23 74 2017 52 1922 02/24 79 1982 55 1985 FAY Records: Date | High Year | High Min Year ------------------------------------------- 02/20 82 2014 60 1939 02/21 80 1991 61 1953 02/22 77 2003 56 1989 02/23 80 1922 55 1922 02/24 83 1930 60 1975 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Ellis NEAR TERM...Ellis SHORT TERM...Ellis LONG TERM...np AVIATION...Ellis CLIMATE...Badgett

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