Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 131926 AFDRAH AREA FORECAST DISCUSSION National Weather Service Raleigh NC 226 PM EST Fri Dec 13 2019 .SYNOPSIS... Weak low pressure will move through the Southeast today. High pressure will build in Sunday through Monday. Another frontal system will approach the area Tuesday, moving through central NC mid-week. && .NEAR TERM /THROUGH SATURDAY/... As of 225 PM Friday... A developing off the GA coast this aft/eve will slide northeast along the Southeast and mid-Atlantic coastline through tonight. Even as the low approaches the Carolinas, the wedge may linger over portions of the Triad and NW Piedmont of NC this evening, eroding as this first low exits to the northeast. Meanwhile, the initial Gulf low will follow the same track as the initial low, along the Carolina coast. There may also be a brief lull in the precipitation around midnight or so between the two lows. However, another round of rain is expected overnight before the Gulf low finally lifts through and out of the area Saturday. When all is said and done, 1- 2.5 inches of rain is expected to have fallen since early this morning. Areas of fog are likely to develop overnight, becoming dense at times. Any fog that develops will lift and scour out on Saturday. Lows tonight will be very similar to highs, mid 30s NW to around 50 degrees SE. Highs on Saturday expected to be in the 50s as long as the wedge completely erodes tonight. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 205 PM Friday... The mid level shortwave trough will pivot ENE away from NC Sat night, leaving 100-150 m height rises and clearing/drying conditions as the steering flow flattens briefly to a fast nearly zonal flow. We are likely to see mid-high clouds streaming across the area overnight as a 140+ kt upper jet noses into the region, but overall skies should be fair with nearly normal lows in the 30s. Sun into Mon should be dry and warm, as mild surface high pressure builds from the Gulf over FL/GA early Sun, then shifts E off the Southeast coast late Sun into Mon, in response to a large mid level trough digging over the western and central CONUS and accompanied by an approaching surface cold front. The approach of this trough will result in growing ridging aloft over the Southeast. The cold front looks likely to move into the Mid South region by late Mon; recent GFS runs have sped up slightly, but all models are in fairly good agreement on this timing. Models generally agree that appreciable precip will hold well to our W and NW through 00z Tue. But the low levels will be moistening as the prefrontal warm/moist conveyor belt pumps Gulf moisture into the region, so we can`t rule out a few sprinkles or drizzle late Sun night into Mon. Expect partly cloudy skies Sun trending to cloudy Sun night/Mon with areas of fog and low clouds especially Sun night/Mon morning. Expect temps to be steady or rising Sun night then peaking well above normal Mon, although warming may be delayed a bit in the NW as the cooler/stable air retreats. -GIH && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 220 PM Friday... Rain chances will increase Mon evening and peak late Mon night and Tue along and just behind the cold front passage, as the upper trough slowly pushes eastward with a positive tilt. The GFS has sped up in recent runs, while the ECMWF has trended slower, attributable in part to their differences in northern stream low/trough progression over/N of the Great Lakes, so there is still a lot of uncertainty about timing. But it looks likely that everywhere will see some measurable rain during this window, and will retain high pops. The front should be pushing offshore late Tue or Tue evening, with improving but cooling weather late Tue night/early Wed as an expansive, chilly high starts to build in from the W. Thicknesses drop to 25-30 m below normal, so Wed temps should be cool, although the true Arctic air will hold to our N. Dry weather and fair skies should hold through Fri, with moderating temps, as the departing trough leads to rising heights with the surface ridge holding over the Eastern Seaboard. A mid level shortwave trough may approach from the W late Fri, however with timing differences and the lack of available moisture, impacts should be minimal. -GIH && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... As of 1225 PM Friday... 24 hour TAF period: Primarily LIFR/VLIFR conditions expected through tonight as the rain continues over central NC and areas of fog develop overnight. Brief improvements to IFR (primarily visbys) are possible, but not likely. Some improvement is expected after daybreak Saturday as visbys improve to MVFR/VFR and cigs begin to lift. Rain will gradually move out of the area during the aft/eve, but cigs could remain MVFR or lower through the remainder of the TAF period. Looking ahead: Expect periods of MVFR cigs on Saturday eve/night as a trailing shortwave moves through the area. Some patchy fog will be possible in the pre-dawn hours Sunday morning, but otherwise VFR conditions should prevail Sunday and Monday. Another frontal system will approach from the west mid-week, resulting in a return to sub- VFR aviation conditions and rain. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...KC NEAR TERM...KC SHORT TERM...Hartfield LONG TERM...Hartfield AVIATION...KC is the U.S. government's official web portal to all federal, state and local government web resources and services.