Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 191724 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 124 PM EDT Mon Mar 19 2018 .SYNOPSIS... High pressure with increasing clouds today. Another system arrives Monday night through mid week with periods of rain and snow. Similar system next weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1215 PM Monday... Latest surface analysis indicates temperatures are several degrees warmer than expected. In addition, fewer clouds are evident. Have gone ahead and lowered sky grids for this afternoon and in response, have raised afternoon readings a few degrees. As of 310 AM Monday... Dry for much of the day today, although clouds will be on the increase ahead of approaching shortwave and surface low. Most precipitation will hold off until later this evening, but a slight chance cannot be completely ruled out later this afternoon across the higher terrain, as southeasterly flow increases across the area. With the southeasterly flow, temperatures will warm nicely, particularly across the WV lowlands, where high temps in the upper 50s to mid 60s will be common. Low pressure, and associated precipitation move into the region this evening, with mostly rain forming across the area. There is the possibility of a wintry mix across the northern mountains late tonight and early Tuesday, mainly in the form of sleet/snow/rain. For now, in coordination with other offices, have elected to hold off on any headlines across that area for tonight based on lack of significant accumulations/possible timing issues, and will have the day shift reevaluate, and highlight the wintry precip in the HWO. Dry slot takes hold across the area towards dawn, as the system moves east through the region, but precipitation coverage will increase again towards the end of the near term period into the short period. Still could see a rumble of thunder across the far south later today, but chances are low, with better instability south of the CWA. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... As of 345 AM Monday... As a surface low passes by to our south, a portion of it breaks off and gets picked up by an upper level low across the middle Ohio River Valley Tuesday into Wednesday. Not a lot of confidence in just how this will evolve -- such as where any heavier bands of snow may set up. For the day on Tuesday, have mostly rain, with a brief wintry mix across the northern mountains early on. Cold air then surges in Tuesday night, changing precipitation over to snow for everyone by Wednesday morning. This Tuesday night time period has a decent bust potential on snow amounts due to temperatures. Specifically, just how quickly will temperatures fall after a warm day on Tuesday, and how soon will snow be able to start accumulating. The NAM shows very robust frontogenesis on the NW side of the surface low -- which should drive a mesoscale band of precip across the Tri-state and coal fields Tuesday night. Think temperatures will be too warm for significant accumulations with this, but intensity could partially overcome that. Other area of concern is SE Ohio...where the changeover to snow will happen first. Models showing very wide range of accumulations here, with a low end near 2 inches and high end over 6 inches. Went with amounts of 2-4 inches for now, with the hope that details will resolve better with future models runs and totals can be trended toward higher confidence solutions. Will go with a broad HWO mention of snow Tuesday night into Wednesday. The surface low opens up and exits to the east Wednesday into Thursday with northwest flow snow showers lingering. Could get another decent area of snow across the southern mountains and coal fields Wednesday night, but again models have some variability, ranging from around 2 inches to over 4 inches. Did not put a whole lot of faith in model based snow accumulations during the daylight hours, as the late March sun angle and warm ground has a tendency to greatly reduce accumulations during the day. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... As of 345 AM Monday... Brief high pressure will pass Thursday night and Friday...although the GFS does try to keep some NW flow upslope snow showers across the northern mountains. Did not bite on that with limited moisture. The next system arrives Friday night into Saturday, and could contain a wintry mix on the front side, with rain Saturday and then changing over to snow as colder air rushes in Saturday night into Sunday. && .AVIATION /18Z MONDAY THROUGH FRIDAY/...
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As of 124 PM Monday... VFR conditions with light surface winds through 00Z, although areas of MVFR cigs will likely develop across the mountains after 21Z. Clouds should thicken and lower with MVFR conditions in rainshowers will spread north after 00Z. By 08z, MVFR conditions will prevail across much of the area with patchy IFR or even LIFR conditions in the mountains as well as the southern coalfields. After 09Z, the precipitation will changeover to a wintry mix of sleet and freezing rain across the higher elevations of the northern West Virginia mountains. After 12Z, conditions across the lowland counties to the west of the mountains should improve as southeast downslope winds prevail. Gusty southeasterly winds will develop after 02Z particularly across the higher terrain, with occasional gusts in the teens to lower 20 kt range. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: High through 00Z, then Medium. ALTERNATE SCENARIOS: Timing of precipitation and associated restrictions may vary from 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. UTC 1HRLY 17 18 19 20 21 22 23 00 01 02 03 04 EDT 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H H M L L HTS CONSISTENCY H H H H H H H H H M L L BKW CONSISTENCY H H H H H M M M M L L L EKN CONSISTENCY H H H H H H H H H M M M PKB CONSISTENCY H H H H H H H H H M M M CKB CONSISTENCY H H H H H H H H H M M M AFTER 18Z TUESDAY... IFR possible in precipitation Tuesday afternoon through Thursday.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...MZ/SL NEAR TERM...JSH/SL SHORT TERM...MZ LONG TERM...MZ AVIATION...JSH is the U.S. government's official web portal to all federal, state and local government web resources and services.