Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 131037 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 637 AM EDT Tue Mar 13 2018 .SYNOPSIS... Cold upslope flow continues through Thursday, with upper level disturbances, the strongest crossing tonight into Wednesday. A warming trend is on tap for the upcoming weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 635 AM Tuesday... Forecast on track. As of 450 AM Tuesday... Northern stream upper level low digging into the Great Lakes, and a southern stream low moving northeast off the east coast, dumbbell about each other, before nearly merging by 12Z Wednesday. Meanwhile, a pair of short wave troughs, moving down the back side of the northern stream low, cross this evening, and overnight tonight. The second one is stronger, but both track near the southern end of the forecast area. This places the area on the cyclonic shear side of the jet, and southern portions of the area under the strongest lift. Upslope snow showers continue in and along the west slopes of the mountains, enhanced this afternoon on diurnal heating beneath falling heights, and then the short wave troughs tonight. Also expect the radar will be dotted with snow showers throughout the area this afternoon, and then bands of snow showers occur across southern to central portions of the area tonight, including out across the lowlands, with the help of a Lake Michigan trajectory. Snow squalls are also possible as the first short wave approaches late today, with the heating of the day providing added instability. Model snow squall parameters support the potential for snow squalls with the the second short wave overnight tonight as well, as well as generally in, and along the western slopes of, the mountains, later today and tonight. Temperatures needed little adjustment in light of the latest near term guidance blends, with colder air on tap tonight. This, with favorable dendritic growth, will support efficient snow accumulation. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... As of 255 AM Tuesday... Exiting trough axis embedded in the closed low aloft reinforces the cold air and upslope northwesterly flow snow showers for the mountains. This feature, beginning in the last few hours of the near term period and lasting into the short term, will likely be the source of the best snow potential in the pattern. One last surface trough rotates southward through the region giving one last enhancement to the snow for the mountains Wednesday night, and then the closed low finally kicks out to the northeast. Temperatures remain well below normal. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 255 AM Tuesday... Height recovery occurs, as well as 850mb temperature recovery, heading into the end of the week with weak high pressure influences briefly making an appearance. Another closed upper low pushes into the Ohio Valley west to east, but will be filling as it does so, along with its surface low counterpart. POPs are representative of a decaying precipitation shield as it enters our CWA. The next chances for precipitation come from another low pressure system Monday. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... As of 635 AM Tuesday... Low level northwest upslope flow will continue through the period, with gusty surface winds. This will bring stratocu that will be MVFR at times at night, but the mixing layer will grow deep enough by day for VFR ceilings. The upslope flow will also lead to snow showers at times in, and just west of, the mountains, with MVFR to IFR conditions. The greatest coverage of snow showers will be this afternoon on diurnal heating, and tonight, as an upper level disturbance crosses. Snow showers could also affect the lowlands this afternoon and night. The afternoon coverage will dot much of the radar, while overnight coverage tonight is more likely to set up in a band somewhere through central and southern WV. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of MVFR stratocu and snow showers may vary. TAFs may need updated as individual snow showers or bands develop. Gusty winds will tend to vary. 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. UTC 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 EDT 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY H H H H H H H H H M M M HTS CONSISTENCY H H H H H H H H H H M M BKW CONSISTENCY H H H M M M H H H H M M EKN CONSISTENCY H H H M M M M L L L L M PKB CONSISTENCY H H M M M M H L M M M M CKB CONSISTENCY M H H H H M M L M H M M AFTER 12Z WEDNESDAY... IFR conditions possible in snow showers at times through Wednesday night. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Winter Weather Advisory until 2 PM EDT Wednesday for WVZ520>523-525-526. Winter Weather Advisory until 8 AM EDT Wednesday for WVZ033- 034-515>519. OH...None. KY...None. VA...Winter Weather Advisory until 8 AM EDT Wednesday for VAZ004. && $$ SYNOPSIS...TRM/26 NEAR TERM...TRM SHORT TERM...26 LONG TERM...26 AVIATION...TRM is the U.S. government's official web portal to all federal, state and local government web resources and services.