Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 230644 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 244 AM EDT Sun Jul 23 2017 .SYNOPSIS... Strong to severe thunderstorms are still possible Sunday with risk for heavy rainfall and potential flooding. Fronts cross late Sunday and again late Monday. High pressure midweek. && .NEAR TERM /THROUGH TONIGHT/... As of 230 AM Sunday... Thunderstorm clusters tracking east-southeast along the OH River into southwest WV/northeast KY have been exhibiting a general weakening trend. Updated POPS based on the latest HRRR which indicates the southern 1/2 to 1/3 of the CWA will see rain through the predawn and into the early morning hours. Well-defined shortwave over northern MN early this morning will move east through the Great Lakes with general synoptic trough amplification into the central Appalachians by the end of the period. Several vorticity maxima will rotate through the southern edge of the trough and ahead of a cold front pressing southeast through the OH Valley. The combination of increasing large scale forcing/ascent associated with vort maxes, residual outflow boundaries, rich moisture (70+ dewpoints) and moderate instability should all prove effective in generating more storms this afternoon into tonight. Much like yesterday, storms will be capable of isolated damaging winds and localized heavy rainfall. 1-3hr FFG is quite low (an inch or less) across the northern 1/2 of the CWA and may need to extend FFA beyond 12z expiration. Lastly, max HX values approach 100F around the Tri-State area and will need to monitor convective/cloud trends for possible advisory. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 315 PM Saturday... Models in good agreement in a significant short wave amplifying the northern stream over the eastern U.S., which finally drives the very deep and moist unstable air with the cold front eastward across most the area Sunday night. Even though the front gets hung up in the mountains by Monday morning, the really deep moisture and convection should continue eastward with the main departing short wave. By Monday morning, we expect most of the area to be dry, except across the far southern coal fields and southern mountains where some lingering convection may continue. Thereafter, models have another short wave and cold front dropping southeast through the Great Lakes and across the area Monday afternoon and night. Even though moisture will be more limited with this feature, there will be enough moisture to combine with diurnal heating to fire up a band of convection with the front. Things will finally die down Monday night, with most areas dry by Tuesday morning. However, again, this new front will struggle to exit the far south and have left a few showers possible there Monday night into Tuesday morning. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 340 PM Saturday... High pressure builds in briefly Tuesday and Tuesday night with slightly cooler but drier air. However, models agree in another short wave and front diving southeast across the area Wednesday and Wednesday night, with enough dynamics, moisture and instability to fire yet another band of convection ahead of the front. But it will be a bit cooler and less on the summer heat and humidity. But despite this latest short wave and front, the models quickly lift out the upper trough and return the front northward Thursday, which meanders across the area for the later part of the work week. Again, lots of moisture will be available to keep things very unsettled with the meandering front, although temperatures are progged to be tempered by the clouds and precip. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... As of 230 AM Sunday... Upstream thunderstorm clusters tracking east-southeast along the OH River will bring rain to the southern 1/2 to 1/3 of the airspace during the predawn hours and into the early morning. Can`t rule out a few showers/storms into the northern airspace but these would be more isolated in coverage. Restrictions in the northern airspace should be related to fog/low cigs with thunderstorm with rain brief mod-hvy rain at KHTS/KCRW. High res guidance shows a break in convection 12-15z. Additional storms are expected to develop across the airspace during the afternoon and evening and have indicated VCTS after 17z. Storm could persist into tonight but confidence is low on the evolution. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Convection could be less widespread than currently forecast. Conditions on Sunday may not improve as quickly as 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 SUN 07/23/17 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10 CRW CONSISTENCY H H H H H H H H H M H M HTS CONSISTENCY H H H H H H H H H H M M BKW CONSISTENCY H H H H H H H H H H H M EKN CONSISTENCY L H M M M L M L M M M L PKB CONSISTENCY M L L L L L M L M M M L CKB CONSISTENCY M M M M M M M M M M L L AFTER 06Z MONDAY... IFR possible Sunday night in heavy showers and thunderstorms. Fog and low ceilings possible early monday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Flash Flood Watch until 8 AM EDT this morning for WVZ007>011- 014>020-027>032-039-040-517>526. OH...Flash Flood Watch until 8 AM EDT this morning for OHZ066-067- 075-076-083>086. KY...None. VA...None. && $$ SYNOPSIS...JMV/SL/99 NEAR TERM...SL/99 SHORT TERM...ARJ/JMV LONG TERM...JMV AVIATION...SL/99

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