Area Forecast Discussion
Issued by NWS Charleston, WV

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451 FXUS61 KRLX 230247 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 1047 PM EDT Sat Jul 22 2017 .SYNOPSIS...
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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.
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&& .NEAR TERM /THROUGH SUNDAY/...
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As of 1042 PM Saturday... Sent an update to adjust PoPs according to latest radar images. Radar shows like a boundary sinking south with convection along it. Frequent lightning, brief torrential rain, and strong gusty winds are possible with these storms. These storms will affect the southern half of the area through at least midnight. As of 845 PM Saturday... Adjusted hourly temperatures since cooling showers/storms and clouds have decrease temperatures about 10 degrees across the northern third of the area since this afternoon. Rest of forecast remains on track. As of 710 PM Saturday... Sent update to remove some counties out of the severe thunderstorm watch. Rest of forecast remains on track. As of 354 PM Saturday... A severe thunderstorm watch has been issued for parts of southeast OH and portions of the northern half of WV until 10 PM. As of 155 PM Saturday... MCS moved across northern zones this morning, producing generally an inch or so of precipitation. Area in the warm sector of a low pressure system moving across Great Lakes region, with sct showers and thunderstorms popping up area wide in the warm, humid, unstable conditions. With the lower FFG/wetter soils across the north, and the potential for additional MCS overnight, went ahead an hoisted a flash flood watch for the area through Sunday morning. This may need to be expanded in area or even in time as we progress, but for now, just decided to issue for the wetter areas/greatest threat region. In addition to flooding issues, the potential for severe exists through much of the night, with strong shear on the order of 40+ kts. SPC has issued a slight risk for most of the CWA through 12Z Sunday, with a slight risk area wide on Sunday for an additional severe thunderstorm threat, as the cold front approaches the area from the north. Frontal boundary should be entering SE Ohio zones towards the end of the period.
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&& .SHORT TERM /SUNDAY NIGHT 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 /03Z SUNDAY THROUGH THURSDAY/...
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As of 730 PM Saturday... Numerous showers and scattered thunderstorms, some with heavy rain will continue to affect the northern sites at least through 01Z. Mostly MVFR conditions will prevail outside brief periods of IFR/LIFR along their path. Uncertain whether convection will affect northern sites directly, so coded VCTS overnight. Expect MVFR and IFR conditions in vicinity of storms, along with strong gusty winds. A look at boundary layer winds indicate 15-20 knots across the south, and 5-10 knots across the north. The stronger winds and expected cloud cover could prevent dense fog from development. However, the northern sites have received enough rain during the afternoon and evening hours. Post fog will be possible once the pcpn ends but should not last much. For Sunday, another stormy day. SPC has the area under a slight risk for severe weather. Damaging winds will be the main threat. IFR or worst conditions can be expected along convection path. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z 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 00Z MONDAY... IFR possible Sunday night in heavy showers and thunderstorms.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...Flash Flood Watch until 8 AM EDT Sunday for WVZ007>011-014>020- 027>032-039-040-517>526. OH...Flash Flood Watch until 8 AM EDT Sunday for OHZ066-067-075-076- 083>086. KY...None. VA...None. && $$ SYNOPSIS...JMV/SL NEAR TERM...SL SHORT TERM...ARJ/JMV LONG TERM...JMV AVIATION...SL

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