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. --
531 FXUS62 KRAH 191921 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 221 PM EST Fri Jan 19 2018 .SYNOPSIS... Arctic high pressure over the southeastern United States will slowly move south through Saturday. This will allow a much milder southwest flow, especially noticeable this weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Friday... Little change required to the near term forecast. May cancel the winter weather advisory for black ice prior to 12 PM expiration as sfc temperatures warm well above freezing. 12Z GSO upper air sounding depicts a strong sfc based inversion. While temperatures at the surface were in the lower 20s, at 300 ft AGL, temperatures were in the upper 30s. In addition, the sounding depicted a deep wly flow overhead. A minor s/w passing to our north and a weak area of high pressure to our south will maintain this wly flow through tonight. the mild air mass aloft coupled with abundant sunshine will go a long way in eroding the snowpack over portions of central NC today. Still, the relatively deep snowpack over portions of the northern Piedmont will still modify temperatures. So while areas that have bare ground will see afternoon temperatures in the lower 50s, temperatures in the low-mid 40s will be common where widespread snow covers the ground. Tonight, while the air mass will continue to experience modification thanks to the wly flow, residual snowpack will continue to influence temperatures. Thus, expect another night/early morning with a wide variance in minimum temperatures, ranging from the mid 20s where the ground is bare, to the upper teens/around 20 where the snow is still several inches deep. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 255 AM Friday... Continued moderation as the arctic high and residual cold air mass gets lifted out by increasing SW flow and continued melting snow. Sunny skies Saturday will allow warming into the mid 50s to near 60. The snow melt regions should continue to struggle with highs in the lower 50s. Clear and chilly Saturday night, but not as cold with more moderation. Lows 25-30 north-central Piedmont ranging into the mid 30s south. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 220 PM EDT Friday... Southern stream shortwave trough traversing the northeastern GOM and Florida Peninsula will provide little more in the way of some thin high clouds across central NC on Sunday. Meanwhile, sfc high over the SE US will eventually shift offshore Sunday night/early Monday. This will translate into a continuation of dry and moderating conditions, with highs Sunday afternoon ranging from mid/upper 50s NW to to lower/mid 60s SE. Milder min temps Sunday night as well, owing to strengthening southerly return flow and extensive high level cloud spreading east of the mountains, well downstream of the closed low and highly amplified trough advancing east through the nation`s mid-section. The closed low will track NE from the Upper MS Valley to SE Canada by Tuesday, which is coincident with the timing of the trailing cold frontal passage through the region. Models currently indicate a band of showers will accompany the frontal passage, but given how far removed central NC is from the better forcing, expect precipitation amounts to be on the light side, driven primarily by the WCB. Highs Monday, just ahead of the front, will be similar to Sunday`s mild temps, followed by a brief cool done behind the cold front Wednesday and Thursday. Temperatures will begin to moderate on Friday, with the approach of yet another amplified long wave trough advancing east into the Central US. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... As of 120 PM Friday... There is a high likelihood that VFR parameters will persist across central NC through 00Z Sunday as high pressure to our south maintains good to excellent aviation conditions. The caveat to this is that a few model members are hinting at the possibility of patchy low clouds and/or fog early Saturday morning in vicinity of the snowpack across the Piedmont of central NC. At this time believe this probability is low tonight, though a better potential for low clouds and fog may exists late Saturday night-early Sunday morning. In the long term, expect mainly VFR parameters through Monday afternoon, aside from the chance for late night/early morning fog early Sunday morning. An approaching frontal system may bring enough moisture to lower ceilings into the MVFR category Monday night through early Tuesday morning along with a few rain showers. Otherwise VFR parameters anticipated Tuesday afternoon through Wednesday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...WSS SHORT TERM...Badgett/BSD LONG TERM...CBL AVIATION...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.