Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 200012 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 812 PM EDT Fri May 19 2017 .SYNOPSIS... Cold front moves in from the west tonight, and then lifts back north, keeping area unstable this weekend. A new cold front crosses from the west Sunday night. High pressure Monday night. && .NEAR TERM /THROUGH SATURDAY/...
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As of 810 PM... Canceled watch 247 showers and thunderstorms move east and weaken. Severe wording removed from grids / forecast. As of 515 PM Friday Surface low pressure located just northwest of the CWA with a cold front extending south-southwestward from it, eventually tailing back to the southwest through the lower Ohio River Valley as of 5 PM. CAPE values were up around 2500 J/kg ahead of the storms but the shear was largely north of the low pressure center and most of the storms. However, 15 to 20 kts h85 flow and 25 to 30 kts mean h85-h5 flow could still support some storm organization. Adjusted PoPs, clouds and thunder to better reflect line of storms along cold front traversing east across the area overnight. Severe weather wording added where watch 247 is in effect until 11 pm over much of the middle Ohio Valley, then the intensity and coverage decrease overnight. As of 205 PM Friday... The convection that moved into the southern CWA this morning has completely disrupted the overall synoptic setup, so there is some disarray to the activity this afternoon and what is expected later tonight. Got a mesohigh developed where the decaying convection/stratiform rain shield resides from the morning activity, with a northerly moving outflow boundary sparking the next round of convection across the northern tier. This has made the warm front over the area all but impossible to locate. The cool mesohigh has either made a pocket within the warm sector that is trying to move north, or it is holding up the front. Either way, modification of what is left over of heating today could be enough to get another round of isolated convection into the evening as the synoptic flow of the warm sector gets going again. High res models indicating another wave of activity moving in from the northwest heading into early tonight, so ramp the POPs up to likely in this area. Overall the activity has remained largely below severe limits, and expect that trend to continue, although given the slight risk that was extended into the area, isolated severe cannot be ruled out. Flow aloft still remains a limiting factor here. Will need to watch the coal fields for additional rain with well over an inch falling earlier this morning.
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&& .SHORT TERM /SATURDAY NIGHT/... As of 230 PM Friday... Saturday night will feature a lifting warm front to the northeast. Showers and thunderstorms will be possible during this time. Any storm that does move across the area will be capable of heavy rain. Additional rain will accompany the cold front on Sunday. As the frontal system moves east, rainfall will diminish during the overnight hours Sunday. Areas that have already received heavy rainfall from Friday morning and afternoons storms should be closely monitored for potential flash flooding during this weekend. && .LONG TERM /SUNDAY THROUGH FRIDAY/... As of 230 PM Friday... A period of cooler and drier air will follow the exiting cold front early Monday. However, the chances for rain return by midweek with the next frontal system. Temperatures will return to a more seasonable level during this period. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
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As of 810 PM Friday... Showers and thunderstorms associated with a cold front were approaching the Ohio River from the west as of 00Z. These showers and thunderstorms will likely affect HTS and PKB during the first 3 or 4 hours of the forecast, arriving by about 01Z. MVFR ceilings and MVFR to IFR visibility are possible, along with gusty winds. The showers and thunderstorms will weaken as they move east, possibly affecting CRW and CKB 03-08Z. By the time the precipitation reaches the WV mountains after 06Z, only showers with minimal aviation impacts are expected. As the cold front moves into the area, MVFR stratocu is likely overnight into Saturday morning, but not quite making it as far southeast as CRW and BKW. Also, valley fog forming overnight may become dense, depending on the rain. Conditions should improve to VFR by late Saturday morning, except MVFR stratocu may hang on at PKB into the afternoon. Also, showers and thunderstorms are likely to be around Saturday afternoon, on account of the front still being in the area, and beginning to retreat north. Light southwest flow early on, with possible strong gusts in thunderstorms over the middle Ohio Valley, will become light and variable overnight and basically remain so on Saturday. Light to moderate west flow aloft will become light west to southwest on Saturday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE: Low. ALTERNATE SCENARIOS: Amendments likely for changing environments from thunderstorm/rain passage, and post rain nocturnal fog. 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 22 23 00 01 02 03 04 05 06 07 08 09 EDT 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 CRW CONSISTENCY H H H H H H H H H H L L 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 L L L EKN CONSISTENCY H H H H H H M M L L M M PKB CONSISTENCY H H H H H H H H L H M L CKB CONSISTENCY H H H H H H H H H H L L AFTER 00Z SUNDAY... Isolated IFR possible in fog Saturday, Sunday and Monday nights, and in showers and thunderstorms Sunday into Sunday night.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...ARJ/TRM/26 NEAR TERM...TRM/26 SHORT TERM...JB LONG TERM...JB AVIATION...TRM

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