Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 050216 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 916 PM EST Sun Dec 4 2016 .SYNOPSIS... A weak system is crossing the area tonight. A low pressure system crosses Monday night and Tuesday. Briefly milder in its wake mid week. Colder after a cold front passes Thursday. && .NEAR TERM /THROUGH MONDAY/... As of 900 PM Sunday... Increased PoPs as upper level short waves transits area. Radar and obs showing widespread rain over the area. Weak front passes in the early morning hours of Monday. Not expecting a lot of QPF, but what does fall in the mountains may fall as freezing rain as a tongue of warm layer aloft slides into the region, so maintaining winter storm advisory there. Slick roads are the main concern. As of 230 PM Sunday... Warm air advection aloft and weak isentropic lift is bringing light rain to Southwest Virginia this afternoon. The rain has been confined mostly to our south with just mid and upper level clouds currently across the forecast region. Fairly dry air in the low levels has mostly kept precip at bay and seeing just mid level clouds across much of the region for now. Low level southeast flow this afternoon and into the evening will likely produce upslope clouds and an isolated shower in the Eastern Mountains but not expecting widespread PoPs to enter the region until later this evening with approaching short wave. The weak shortwave moves through late tonight into tomorrow morning. Dewpoints are mostly in the mid to upper 20s and as precip moves in this drier air at the surface will likely allow for some evaporational cooling. Although confidence is still fairly low at this time, there is certainly still some potential for a wintry mix, including periods freezing rain overnight, mostly across the parts of Randolph and Pocahontas counties. Not expecting significant impacts, but a trace to a couple of hundredths of ice accumulation could make for slick travel. Have decided to leave current winter weather advisory as is for now. High pressure builds back in for a brief period tomorrow and conditions should improve late morning into the early afternoon. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 315 PM Sunday... No major changes to the short term forecast with decent model run to run consistency. Trickiest part of the forecast will be the cold air trapped in the far northern mountain valleys at the onset of precipitation, as this would likely translate to another marginal freezing rain issue in isolated areas. Will transition to rain eventually, and this will be more of a liquid precipitation event as opposed to the onset freezing rain potential. For the timing, isentropic lift on the 295K surface arrives after 06Z Tuesday over the Tug Fork Valley and will overspread the rest of the CWA fairly quickly. Frontogenetic forcing will also pass through quickly, while the center of low pressure passes and drags a cold front through into Tuesday night. Still looking at around an inch of liquid precipitation for the system. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 325 AM Sunday... Cold front for Thursday is looking a bit weaker in latest model runs with the closed 500mb low not as deep as previous runs. Southward penetration of the 850mb thermal trough will be less as a result of the weaker system overall, but will still get near -16C down into the middle Ohio Valley for the end of the week. Post frontal/cold advection snow possible behind the front. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... As of 900 PM Sunday.... Cold front moving through bringing light rain and a good chance for IFR conditions at all sites. For this package, trended lower due to upstream obs and the NAM suggesting lower ceilings. Kept IFR in through early monday when conditions should improve as high pressure builds again. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of precipitation and MVFR/IFR conditions tonight may vary. May have the visibilities in TAFs too high. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE MON UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 CRW CONSISTENCY H H H H H H H H M H H L HTS CONSISTENCY H H H H H H H H H H H L BKW CONSISTENCY H H H H L H L L M M L L EKN CONSISTENCY H H M H H H M H M M M L PKB CONSISTENCY M H H H M M M M M M H M CKB CONSISTENCY H H M M M H H M M M M M AFTER 00Z TUESDAY... IFR possible in rain on Tuesday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Winter Weather Advisory until 6 AM EST Monday for WVZ523-524- 526. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JW/MPK/26 NEAR TERM...JW/MPK SHORT TERM...26 LONG TERM...26 AVIATION...JW

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