Area Forecast Discussion
Issued by NWS Charleston, WV

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356 FXUS61 KRLX 180316 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 1016 PM EST Wed Jan 17 2018 .SYNOPSIS... High pressure passes south of the area through Thursday. Southwest flow of milder air Friday through the weekend, with a warm front passing Saturday. Cold front Monday. && .NEAR TERM /THROUGH THURSDAY/... As of 1015 PM Wednesday... Seeing some readings close to zero in the outlying locations where it has cleared and some decoupling has occurred. It remains a challenging low temperature forecast overnight for the reasoning laid in the earlier discussion. Case in point, LHQ was -3 a few hours ago and has now jumped 13 degrees upon receiving a puff of wind. As of 700 PM Wednesday... Clearing line is progressing eastward this evening, with southeast Ohio, northeast Kentucky, and western West Virginia under a starry sky. This clearing will continue to progress east through the evening, though likely slowing up once east of the I79 corridor. A challenging temperature forecast exists overnight. A clearing sky and good snowpack would typically scream tank overnight, scoring big points on MOS guidance. However, surface high resides across the southern states and winds in the H925 to H85 layer will be increasing late the 25 to 35 kt range. This would help to mitigate the freefall especially on the hilltops, while the high ridges actually rise late with WAA. I did not get too carried away with lows as a result, but I did allow significant drops in the valleys and hollers. The thinking there is that a significant inversion will setup this evening that should be able to stiff arm the increase in boundary layer winds overnight. In these locations, -3 to -5 below was coded up, with lower single digits elsewhere. This may be conservative, and I will likely have to further adjust later this evening depending on the trends. As of 1110 AM Wednesday... Guidance show a broad high pressure located over the south central states, with a ridge extending northeast into KY and WV through Thursday. SFC obs indicate flurries still occurring at some sites. Models suggest that there still enough sfc to low level moisture over the area tonight. This moisture will continue squeezing against the mountains to produce flurries or light snow tonight. No additional snow accumulations expected. Weather charts show a broad sfc high pressure centered over the south central states, with a ridge extending northeast into KY and WV. This feature will keep light to calm flow overnight. With snow on the ground, and skies trying to clear from west to east overnight, temperatures are expected to plummet into the lower single digits lowlands, and below zero over the higher elevations northeast mountains. With the wind factor, over the elevated terrain will produce wind chill values from -3F to -20F. These conditions prompt the issuance of a Winter Weather advisory for dangerous wind chills tonight through 14Z Thursday. Went with the coldest guidance tweaking down some degrees over the classic cold spots. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 230 PM Wednesday... Overall, short term forecast is very quiet with a warming trend as we head into the weekend. Ridging and high pressure is basically overhead through the entire period. This will moderate our temperatures nicely, with highs climbing into the low to mid 40s on Friday and mid to upper 40s on Saturday. Clouds will be on the increase Saturday afternoon as a warm front approaches from the southwest. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 240 PM Wednesday... Fairly good agreement among the guidance now with a warm front crossing on Saturday night into early Sunday morning. May see a few light rain showers through the day on Sunday, but for the most part we will be within the warm sector and relatively stable conditions aloft. Strong low pressure will track into the Great Lakes region by early Monday morning. This system will drag a cold front across the forecast area on Monday, with widespread rainfall looking more and more likely. PWATs are showing to be slightly anomalous in the latest GEFS runs so with the decent moisture, would not be surprised to see some spots get an inch of rain out of this. Rivers remain quite high with some ice jams in spots. There is some potential for some minor flooding, but generally not thinking any major issues at this time. Any lingering precipitation will change over to light rain and possibly snow showers Monday night, with light accumulations possible as colder air presses in behind the front. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... As of 705 PM Wednesday... Clearing has worked east of PKB/HTS as of 00Z. MVFR stratus and flurries will gradually erode elsewhere this evening. This will take longest across the mountain terminals, perhaps until after 06Z. VFR conditions Thursday with southwesterly surface winds 10 to 15 kts in the afternoon. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of clearing overnight may vary a few hours at BKW/EKN. 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 THU 01/18/18 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09 CRW CONSISTENCY M M M M M M M M M M H M HTS CONSISTENCY H H H H H H H H H H H M BKW CONSISTENCY M M M M M M M M M M H M EKN CONSISTENCY H M M M M M H M M M H M PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY M M M M M M M M M M H M AFTER 00Z FRIDAY... None. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Wind Chill Advisory until 9 AM EST Thursday for WVZ520-522>526. OH...None. KY...None. VA...None. && $$ SYNOPSIS...ARJ/SL NEAR TERM...ARJ/30 SHORT TERM...MPK LONG TERM...MPK AVIATION...30 is the U.S. government's official web portal to all federal, state and local government web resources and services.