Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 300626 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 120 AM EST Wed Nov 30 2016 .SYNOPSIS...
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A cold front will cross the area this evening through early Thursday. Behind the front, high pressure will build into the region over the remainder of the week.
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&& .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 942 PM Tuesday... Central NC is currently in a forcing lull as we wait for the next shortwave trough(currently over the Southern Plains)to rotate newd through the base of the synoptic upper trough that will move slowly eastward into Central US. As such, with weak WAA in the continued deep swly flow the primary forcing mechanism overnight, rain chances will be pretty limited, with only isolated showers expected. Probably the biggest question overnight is whether we will see areas of dense fog develop across the western piedmont as is indicated by some of the NCAR and HRRR guidance. While the moisture profile is supportive, it appears that there should be a sufficient pressure gradient to keep sustained winds at least in the 5 to 10 kt range which should mitigate the potential for widespread fog. Mild overnight lows in the 60s. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... As of 300 PM Tuesday... A series of shortwave perturbations will help amplify the longwave trough over the Midwest and enhance the line of pre-frontal convection over western NC on Wednesday. Given the slow progression of the convection as the parent upper low re-develops over the eastern Great Lakes/southeast Canada, Wednesday could remain dry for much of central NC. Strong southerly flow will continue to usher warm moist air into the area (highs in the low to mid 70s), however the persistent mid-level dry air will remain in place until the convection moves in. The majority of the rain is expected to occur after 7 PM and will be quick hitting, moving from the NW (Triad) to the SE (NC coast) by early Thursday morning. Rainfall totals will likely be highest in the NW and lowest in the southeast ranging from quarter of an inch to an inch. The cold front will also progress eastward through Central NC overnight. As a result of the current fropa timing, lows should bottom out in the mid 40s to upper 50s given that the winds will remain in the 5-10 mph range. The low-mid level flow will be rather strong ahead of the front and could result in fairly strong wind gusts, however instability, even during peak heating, is low and decreases prior to the arrival of the convective line. Central NC is in a marginal risk for Wednesday, however if thunderstorms are able to become strong/severe, the main threat would be isolated damaging wind, though the confidence is low at this time. && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 315 PM Tuesday... Expect a return to more seasonable temperatures behind the cold front, though highs Thursday may still be in the mid 60s across the southeast, as surface high pressure builds into and over the region. Highs will be mainly in the low to mid 50s through the weekend and lows in the low to mid 30s should prevail into early next week. Though westerly winds may remain a bit breezy on Thursday, the pressure gradient should slacken as the high builds in from the west. The result will be a trend toward clear skies and light winds through Friday Night. The big forecast problem continues to be how the next weather system evolves. The models are coming into slightly better agreement, trending toward each other. Generally, an upper level low cuts off over the southwest U.S on Saturday. It gets absorbed into the next trough as it amplifies over the Rockies. The resultant shortwave energy will help precip develop over the Midwest as it impinges on the upper level ridge. Though the amplitude, speed, and timing of this system are still highly uncertain, expect precipitation chances to increase Sunday into early next week, though for now it appears the surface high may hold over the region through the weekend. && .AVIATION /06Z Wednesday Through Sunday/...
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As of 120 AM Wednesday... Moist southerly flow continues across central NC this morning with a broken band of light showers moving north through the area. Ceilings, which are VFR from RWI to FAY and IFR/LIFR from RDU to GSO/INT, should lower further prior to 12Z. An area of IFR ceilings will likely spread north through the coastal plain to RWI and FAY, while LIFR ceilings should remain in place at GSO/INT. Light southerly winds will prevail, and local wind profile data suggests any low level wind shear wind 00Z has diminished as winds aloft weaken. The forecast for today is a little uncertain regarding the timing of improvements in conditions, but ceilings are expected to lift to VFR at RWI/FAY/RDU by this afternoon, with MVFR potentially holding on that GSO/INT. Winds will increase to near 15kt out of the south and gust to near 30kt, increasing as ceilings lift. A cold front and a strong line of storms will be approaching from the west this evening, and is expected to move east across central NC between 00Z and 06Z (this evening). The line should lose some of its vigor with time, but a few strong storms and gusts to 40-45kt are possible, along with heavy rain and very low ceilings/vsbys. Outlook: High pressure with fair weather is expected for thursday into Saturday. A storm system will approach the region for Sunday with a period of adverse aviation conditions.
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&& .CLIMATE... Record high minimums for 11/29 RDU 62 1934 FAY 66 1990 GSO 57 1957 Record highs for 11/30 RDU 77 2006 FAY 80 1927 GSO 74 1991 Record high minimums for 11/30 RDU 62 1934 FAY 62 2001 GSO 62 1934 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...KDS NEAR TERM...CBL SHORT TERM...KCP LONG TERM...KCP AVIATION...Smith CLIMATE...RAH is the U.S. government's official web portal to all federal, state and local government web resources and services.