Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 080859 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 359 AM EST Fri Dec 8 2017 .SYNOPSIS...
-- Changed Discussion --
A stationary front will linger just off the Southeast coast through Saturday. A potent upper-level trough near the Mississippi River this morning will move east and approach the Southeast on Saturday. A cold front will move east across the region late Saturday. High pressure will extend into the region on Sunday and Monday before another cold front moves through the region late Tuesday.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH SATURDAY/...
-- Changed Discussion --
As of 330 AM Friday... ...Will be issuing a Winter Weather Advisory for the Northwest and Northern Piedmont including the Triad area for 1 to possibly 2 inches of wet snow... Key changes with this forecast cycle... 1) Light rain will change to mostly wet snow across the Piedmont during the mid/late morning to around midday. 2) Temperatures will be steady or slowly falling today into the mid 30s across the interior Piedmont by early afternoon. 3) We have increased the snow accumulations to 1 to possibly 2 inches. A few localized spots could experience higher amounts in so called snow island where precipitation rates are higher. 4) A warm nose in the lower atmosphere across the eastern Piedmont and Coastal Plain will change any wet snow back to rain tonight. National radar composite shows a large area of rain extending from southern Texas northeast across the Deep South into the Carolinas associated with a very active 150kt jet across ahead of a high amplitude trough across the Central U.S. The air mass across central NC has been modified with surface dewpoints in the lower 30s near the VA border and near 40 toward the SC border. An Arctic cold front is trying to cross the higher terrain of the Appalachians and is just reaching the Blue Ridge with colder and drier air. Regional radar imagery is showing the northern edge of the multiple batches of precipitation across the Southeast now as far north as Atlanta, Charlotte and Raleigh. A few locations across the northern fringe of the precipitation are reporting snow in northern GA and AL. Most of the 00Z model guidance has trended toward a more amplified solution which results in significantly more precipitation (around double the guidance from 24 hours ago for central NC). The stronger forcing also generates greater low level warming and the development of a warm nose of nearly +3C across the eastern Piedmont on Friday evening. The greater precipitation amounts and rates should allow more snow to penetrate the warm boundary layer, chill it and eventually lead to increased snow accumulation amounts. We do not expect the precipitation to be continuous but rather come in waves with periods of light or no precipitation at times. In fact, some guidance is suggesting a lull period moving northeast across the region late this afternoon and evening associated with some sort of gravity wave feature. The precipitation breaks will contribute to diminished accumulation efficiency along with the warm ground temperatures and surface temperatures near but just above freezing. After a minimum this evening, the precipitation is likely to redevelop from the west overnight and Saturday morning as the upper trough approaches. Low and mid level cooling should allow the mixed wet snow and rain across parts of the eastern Piedmont to change to wet snow. All of the precipitation will shift east and diminish during the afternoon. Lows tonight will range from 32/33 in the Triad to 33 to 35 in the Triangle to the mid 30s further southeast. Highs on Saturday will range in the mid 30s to around 40. -Blaes
-- End Changed Discussion --
&& .SHORT TERM /SATURDAY NIGHT/...
-- Changed Discussion --
As of 330 AM Friday... To be updated shortly.
-- End Changed Discussion --
&& .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 155 AM Friday... Dry weather is expected for the medium range period, with below normal temps (some days much colder than others). Surface high pressure will build/extend into the area from the Deep South/Gulf Coast States behind the exiting deep trough Sunday. This will result in a brief warm up through Monday and dry weather, with highs on Sunday in the upper 30s NW to the lower to mid 40s SE. Highs Monday are expected to be in the mid to upper 40s, with some lower 50s across the south. The mid/upper level trough across the eastern half of the country is expected to reload by Tuesday, sending another deep/potent mid/upper disturbance and associated generally dry cold front through the area Tuesday. This will result in a renewed push of cold and dry air on Wednesday, with high temps again plummeting into the 30s and 40s. Moderating surface high pressure will build into the area again on Thursday, resulting in moderating temps by Thursday, with highs in the 40s and 50s. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... As of 120 AM Friday... 24 Hour TAF Period: Another round of rain is overspread the area this morning, with precip expected to expand and continue on an off through the day. Precip has move into southern and eastern portions of the already this morning, with precip expected to spread into the Piedmont through around daybreak Friday. Sub-VFR conditions are expected to develop as the dry low level air mass saturates this morning, allowing for cigs to fall into the IFR/MVFR range. Cigs may fall into the LIFR range late today/this evening. With regard to precip type, we will likely see a rain/snow mix at KGSO/KINT this morning, before changing over to all snow on by mid morning. We may see a brief period of rain mixing in again with the snow during the late afternoon/early evening at KGSO/KINT, before turning over to all snow again late in the evening. Further east at KRDU, a mixture of rain/sleet is expected by early this morning, changing to a rain/snow mix by daybreak (with possibly bursts of all snow), with all rain expected by late afternoon/evening. At KRWI and KFAY, only rain is expected. For locations that see snow, expect we`ll see IFR and possibly LIFR visbys in addition to the cigs. Outlook: Sub-VFR conditions and precip will continue tonight into Saturday. Snow may mix with the rain at the eastern TAF sites on Saturday morning as well, before ending on Saturday afternoon. A return to VFR conditions are expected by late weekend into early next week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BLAES NEAR TERM...BLAES SHORT TERM...KCP LONG TERM...BLAES/BSD AVIATION...BADGETT/BSD

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.