Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 231950 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 250 PM EST Fri Feb 23 2018 .SYNOPSIS... Nearly stationary front meanders about the area into Sunday, as surface waves pass. Areas of significant rainfall possible into the weekend. The front finally charges through on Sunday. && .NEAR TERM /THROUGH SATURDAY/... As of 250 PM Friday... The front that has been oscillating about the area the past few days, surged northward, as a warm front, today. In the warm unstable air, quick-standing convection has fired up, with brief heavy downpours and gusty winds, taking advantage of 45 kts deep layer bulk shear, and nearly a kj/kg CAPE. The convective nature of the precipitation should wane this evening. However, the front sags southward tonight, ahead of several waves that will moves northeastward across the area tonight through Saturday. These frontogenetic waves increase low level convergence along the front overnight tonight, the front and associated convergence then moving back north Saturday, This will bring increasing area coverage of rain, which could be heavy because of elevated convection in strong moisture transport that increases PW values toward 1.25 inches, near the climatological max. Convection may become closer to surface based Saturday, south of the front, with up to 60 kts deep layer bulk shear at times, so strong heavy thunderstorms are possible. Temperatures continue to reflect the baroclinic zone, with daytime insolation south of the front increasing the contrast during the peak heating hours. Guidance was having a somewhat difficult time with this. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 415 AM Friday... We continue to highlight the flooding potential over the weekend. An impressive low level moisture feed into the Ohio Valley will interact with a quasi stationary baroclinic zone to produce rounds of downpours and some storms. It appears there will be two significant rounds of heavy rain. One mid to late morning Saturday into early afternoon across much of the area. The other slated for Saturday night, with the focus across southeast Ohio, as the frontal boundary pivots northwestward as a warm front. This will be followed by a cold frontal passage during the day Sunday, with a continued threat for showers. Qpf amounts around 2 inches are forecast across southeast Ohio, tailing off as once progresses east of the Ohio River. This will result in a renewed threat for flooding across southeast Ohio, with main stem rivers in the zone for significant flooding come Sunday night and Monday. This is especially true for the Ohio River, where major flooding is forecast along many of our official forecast points. The current forecast levels compare closely to Ivan in 2004, which produced significant flooding along the Mighty Ohio. Temperatures will remain very warm over the weekend, with a slight cool down behind the front for Monday. Some showers may linger across the mountains on Monday before the upper trof finally sweeps everything east. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 435 AM Friday... A brief lull in the active weather early next week before another wet system crosses mid to late week. It will remain very mild for this time of year. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... As of 115 PM Friday... Scattered showers and thunderstorms forming this afternoon can bring MVFR tom IFR conditions, along with strong, gusty winds, if one directly impacts a TAF site. The chance for rain, and associated low MVFR to IFR conditions, increases overnight tonight, and then is likely to continue on Saturday, as waves of low pressure move northeastward, along a front over the area. Strong, gusty southwest surface winds will become light and variable tonight, and then remain so for the most part on Saturday. Moderate to strong southwest flow aloft will become light to moderate south to southwest overnight tonight, and then moderate to strong southwest again by Saturday afternoon. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing and degree of lower flight categories may vary with timing of rain, and with possible fog and stratus overnight tonight into Saturday. TAFs may need updated if a thunderstorm approaches this afternoon or early this evening. 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 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H H H H M HTS CONSISTENCY M M M M M M M M H L L L BKW CONSISTENCY M M H H H H H H H H H M EKN CONSISTENCY M M M M M M M M L L M M PKB CONSISTENCY M M M M H H M L L H M M CKB CONSISTENCY H H H H H H M L L M L L AFTER 18Z SATURDAY... IFR possible at times in showers Saturday afternoon into Sunday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Flood Watch through Sunday afternoon for WVZ005>011. OH...Flood Watch through Sunday afternoon for OHZ066-067-075-076- 083>087. KY...Flood Watch through Sunday afternoon for KYZ101>103-105. VA...None. && $$ SYNOPSIS...TRM/RPY/30 NEAR TERM...TRM SHORT TERM...30 LONG TERM...30 AVIATION...TRM

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