Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 271332 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 932 AM EDT FRI MAY 27 2016 .SYNOPSIS... A few weak disturbances aloft within upper level ridge. Slow moving convection with heavy downpours today and Saturday. Southeast flow will raise shower chance Sunday mainly mountains. && .NEAR TERM /THROUGH TONIGHT/... 930 AM significant changes. -shra this morning near the Ohio River gradually starting to dissipate. Still looking at diurnal convection firing up this afternoon in the warm moist unstable atmosphere...with brief heavy downpours. PREVIOUS DISCUSSION BELOW... As for today...The upper ridge just off the SE coast tries to flex more of its muscle into the region. There appears to be a weak axis of lift/moisture on the w peripheral of said ridge which will try to push into the mountains later this aftn as the ridge flexes into the area. This in conjunction with some SE flow providing for some orographic enhancement...will mean for sct shra/tsra this aftn and early eve in the mountains. Not much change in pops inherited from the day shift with a solid 40 to 50 pop in the mountains with isolated mention outside of the mountains. The mountain convection will try to spill off westward into central WV during the early eve hrs. Hard to figure out just how much will survive but current thinking is best chance may lie over E KY...but confidence is too low to insert any higher than low chance. Being under the influence of the upper ridge means for a very light flow regime up thru a portion of the mid levels. As such initial convection over the mountains this aftn will stand up and struggle to maintain updrafts...essentially raining themselves out...meaning downpours are likely in any mountain convection. As for temps today...elected to go a few degrees below guidance outside of the mountains...mainly due to soil moisture from the wet month thus far. Light SE flow will try to counteract that a bit with compressional warming...but still think 88 to 90 will be tough to breach. Any eve shra/tsra over NE KY/SE OH this evening will quickly wane with another summer like night in store. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... A summer like pattern with weak and ill defined upper flow continues for Saturday. Despite the summer like warmth and moisture in a deep but weak south to southeasterly flow...with surface high pressure centered off the Mid Atlantic looks like the dominant synoptic feature will an upper ridge over the area. Thus...with little discernible upper disturbances to help set convection off...will try to be deterministic and focus on diurnal summertime climatology for Saturday...with emphasis on the mountains in southeasterly flow. Thus...will go with slight chance of afternoon convection in the west...and the best chance for afternoon convection in the mountains. Any convection that forms over the mountains will tend to propagate northwestward into the low lands before dissipating Saturday evening. Should be more sunshine Saturday to go on the higher end of temperature the mid to upper 80s...but still tempered by the lush vegetation and moisture. A muggy and uneventful Saturday night is in store once any lingering convection dies Saturday evening. For Sunday...a bit of a change per general model agreement. The long forecast system drifting northwestward to the southeast U.S. Coast saturday will then drift north northwestward Sunday. Whether the surface system makes it to us or not...the supporting weak negatively tilted upper trough pulls even deeper moisture into our region. This brings a better chance for showers and storms...again mainly over the mountain counties. More clouds and showers mean slightly cooler highs on Sunday. For Sunday night...the northern stream looks to drop south just enough to keep the best chance for convection over the mountains. A weak cool front will accompany the amplifying northern stream...pushing southeast across the area Monday. Again...the best chance for convection remains over the mountains in the deepest moisture. Finally some drying looks likely from northwest to southeast during Monday behind the front...but still quite warm with highs in the 80s. && .LONG TERM /TUESDAY THROUGH THURSDAY/... Upper level ridging rebuilds for a dog day summer pattern in the middle of next week, with diurnally driven thunderstorms. An upper level low is progged to roll across southern Canada later next week. It may get close enough to drive a cold front toward the area Day 7 night, so have chance pops persisting next Thursday night. Trended temperatures, mainly highs, down a bit per national guidance in this dirty ridge pattern. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... Scattered convection is expected this afternoon across the mountains...perhaps spilling into the lowlands this evening before waning. At this distance...given only modest confidence of hitting a mountain taf site...have kept mention out of taf attm. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY... FORECAST CONFIDENCE: Medium to high. ALTERNATE SCENARIOS: Timing mountain convection may vary an hour or two. KBKW/KEKN could be impacted by convection late this afternoon. 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 12 13 14 15 16 17 18 19 20 21 22 23 EDT 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 CRW CONSISTENCY M H H H H H H H H H H H HTS CONSISTENCY M M H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M H H H H H H H H H H PKB CONSISTENCY M M H H H H H H H H H H CKB CONSISTENCY M H H H H H H H H H H H AFTER 12Z SATURDAY... No widespread IFR conditions expected. && .HYDROLOGY... The river gauge...and forecast the South Side Bridge in downtown Charleston has not be reading correctly. The NWS hydrologist is working to correct this problem. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JMV/30 NEAR TERM...SL/30 SHORT TERM...JMV LONG TERM...TRM AVIATION...30 HYDROLOGY... is the U.S. government's official web portal to all federal, state and local government web resources and services.