Area Forecast Discussion
Issued by NWS Charleston, WV

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740 FXUS61 KRLX 121117 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 617 AM EST Tue Dec 12 2017 .SYNOPSIS... Strong upper trough brings cold air and snow showers today. Another system arrives by late week with another chance for snow showers. && .NEAR TERM /THROUGH TONIGHT/... As of 415 AM Tuesday... As of 09Z, the cold front was almost through the area and will likely be east of the mountains by daybreak. Looking at upstream observations early this morning, the cold air is rushing in very quickly behind the front as previously forecast. High temperatures for the day have been hit already this morning and we can expect our temperatures to now continue to drop through the day today. Radar is not showing much now, but there have been a few flakes falling at Snowshoe with the front approaching, and we can expect snow showers to become more widespread in the mountains in the NW upslope flow after the front passes. Elsewhere, snow showers/squalls will become more widespread by later this morning to early this afternoon as deep upper trough sinks southward over the area. Decent fetch across Lake Michigan with the NW flow will advect lake moisture to the SE. Current forecast soundings this afternoon indicate a fairly saturated dendritic growth zone, and lapse rates become quite steep this afternoon...not surprising with an 18 decimeters h500 fall from this morning through this afternoon with the negatively tilted upper trough. As mentioned in the previous forecast, expecting to see areas of lake streamers set up and bring short/intense periods of snow at times. This will likely make for interesting travel today, as snow squalls could cause very rapidly changing travel conditions with areas of reduced visibilities and slick roads. Have slightly tweaked snowfall totals overall and as such I decided to include Southeast Raleigh County into the Winter Weather Advisory. Although they don`t necessarily reach snowfall criteria, the thought is that strong wind gusts causing blowing snow with reduced visibilities and wind chills below zero overnight warranted an advisory. All other areas are highlighted in the HWO today, and we will likely handle heavier snow showers this afternoon with Special Weather Statements. Snow showers across the Lowlands will wind down tonight, but upslope mountain snow should continue through the overnight hours. Forecast accumulations across the Lowlands will likely be spotty depending on where the heaviest squalls hit, but definitely not unlikely for a few jackpot areas that see 1 to 2 inches. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... As of 233 AM Tuesday... High pressure builds into the area on Wednesday bringing any remaining mountain snows to an end. As the high builds in, winds should diminish allowing the wind chill advisories to come to an end as well. The dry weather does not last long. An upper level trough and surface low pressure will push east Wednesday night into Thursday bringing another round of wintry precipitation to the region. Another upper level trough and surface low will bring yet another period of unsettled weather from late Thursday night into Friday night. Went with model blends for temperatures through the period. && .LONG TERM /SATURDAY THROUGH MONDAY/... As of 233 AM Tuesday... Another area of high pressure will build in Saturday. As a result, dry weather is anticipated for much of Saturday into early Sunday. Another low pressure system will approach the area from the southwest on Sunday and then push east Sunday night. Expect precipitation associated with this feature to spread into the area on Sunday with precipitation chances expected to continue into Monday. With southwesterly winds in place ahead of the low, expect temperatures to rebound with daytime temperatures above normal on Saturday. The airmass immediately behind the low is not that cold. So expect afternoon readings on Sunday to be close to normal. && .AVIATION /11Z TUESDAY THROUGH SATURDAY/... As of 620 AM Tuesday... A strong upper level system will be pushing into the region today. In the NW flow, we will see lake effect streamers of snow spread across the area and bring periods of heavy snow. In the mountains the snow will be more persistent and IFR conditions will be more likely at EKN and BKW today, while other sites will be more hit or miss. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of snow showers and deteriorating conditions on today will vary from forecast. Conditions may be worse than currently forecast. 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 TUE 12/12/17 UTC 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 EST 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16 CRW CONSISTENCY H M H M M M L H H H M M HTS CONSISTENCY H H H M L M M M H H M M BKW CONSISTENCY H H M H M L L L L L L L EKN CONSISTENCY H M M M L L L L L L L L PKB CONSISTENCY H H M M M M M H H H M M CKB CONSISTENCY H M M M L M M M M L L L AFTER 12Z WEDNESDAY... Scattered snow showers and gusty winds will result in continued areas of IFR into Wednesday morning particularly across the mountains. Another round of snow is expected Wednesday night and Thursday, particularly across the north, with IFR conditions possible. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Winter Weather Advisory until 7 AM EST Wednesday for WVZ516- 518-520-522>526. Wind Chill Advisory from 4 PM this afternoon to 1 PM EST Wednesday for WVZ518-520-522>526. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JSH/MPK NEAR TERM...JB/MPK SHORT TERM...JSH LONG TERM...JSH AVIATION...MPK

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