563 FXUS61 KRLX 031741 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 141 PM EDT Mon Jul 3 2017 .SYNOPSIS... A frontal boundary will sag south through tonight, stalling out across the area through mid week, when it will move back north, with increased heat and humidity. Cold front Thursday night. && .NEAR TERM /THROUGH TONIGHT/... As of 1030 AM Monday...' Previous forecast remains on track. No changes necessary. As of 235 AM Monday... No significant changes were necessary to the near term forecast period. Much of the area should remain dry today under weak high pressure, although there will be a slight chance for showers and thunderstorms across southwest Virginia counties, from a passing upper disturbance, and a slight chance to chance for showers and storms later this evening across the far north as a frontal boundary gradually sags south into the region. Any showers or storms that develop later on in association with this front should gradually dissipate after sunset with the loss of heating. There is a marginal risk just to the north of the CWA and clipping Perry county Ohio for today, but overall, think any sort of severe threat looks to be quite low, particularly with the late in the day timing of convection. The frontal boundary will eventually stall out across the cwa late tonight, and linger through mid week. With the high pressure in control, expecting another hot day, with little breeze. Patchy river valley fog possible again Tuesday morning. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... As of 420 AM Monday... A large upper level ridge builds over the intermountain west this period, while troughiness dominates over the east. That troughiness manifests as split flow, the northern stream over eastern Canada, and an active southern stream passing more or less right over the forecast area. A weak front settles into the area Tuesday and Tuesday night, establishing low level easterly flow. This, and a weak upper level low in the southern stream, may lead to showers and thunderstorms over the mountains, mainly along the eastern slopes, Tuesday afternoon and evening. The low level flow veers to southeast Wednesday and then south Wednesday night. Models otherwise differ on whether the upper level short wave moves on to the east, or slows over the area, or is followed by a second, with a surface reflection possibly developing. Consensus guidance has chance pops over much of the area Wednesday, mainly diurnally driven convection. Yet another upper level short wave trough and surface reflection approach Thursday and cross Thursday night, as the northern stream trough begins to amplify. This will bring a better chance, even likelihood, of showers and thunderstorms Thursday afternoon through Thursday night. The weather pattern beneath the southern stream this period is mainly convectively driven on the mesoscale, with a pair of convective complexes coming down the east side of the developing western ridge, over the plains early this morning. These loosely represent the Tuesday and Wednesday systems, but forecast uncertainty increases with time. Thunderstorms can become a bit strong and heavy Wednesday and Thursday afternoons given CAPE as high as 2 kj/kg and deep layer bulk shear over 30 kts. The flow strengthens Thursday, so Wednesday carries more of a heavy rain threat with slower storm motion and PW values as high as 1.8, while Thursday carries the higher strong wind threat. Neither appear to warrant a hazardous mention at this time. Temperatures and dew points in line with central guidance, with values typical of summer. && .LONG TERM /FRIDAY THROUGH SUNDAY/... As of 420 AM Monday... The upper level pattern amplifies further this period. A short wave trough, and surface low pressure and cold front, move out Friday morning. One or two northern stream short wave troughs then dig southeastward through the area later Friday into Saturday, pushing a surface cold front through the area. This is likely to bring a round of showers and thunderstorms through the area late Friday through Friday night. The weather dries out Saturday once the surface cold front moves through. Canadian high pressure, with its less humid air, should bring a splendid close to the weekend next Sunday. Temperatures and dew points in line with central guidance, and fall a little below normal during the period. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... As of 130 PM Monday... Widespread VFR conditions will prevail today under high pressure. No showers or storms are anticipated to affect any of the terminals. Models suggest an approaching cold front will stall across the extreme northern portions of WV today. None of the models bring associated QPF into our CWA with this feature. Expect once again patchy MVFR and IFR river valley fog tonight from 09 to 12Z. An upper level wave will cross from the south tonight to bring some convection across the southern third of the CWA. Isolated thunderstorms will be possible with brief periods of IFR conditions along their patch. The front will slowly drift south to reach the southern parts of WV Tuesday. Again, IFR/LIFR conditions expected along the heavier showers. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing and development of river valley fog tonight may vary from 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. UTC 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 EDT 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 CRW CONSISTENCY H H H H H H H H H H H M HTS CONSISTENCY H H H H H H H H H H H M BKW CONSISTENCY H H H H H H H H H H H M EKN CONSISTENCY H H H H H H H H H H H M PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H M AFTER 18Z TUESDAY... IFR possible in showers and thunderstorms on Thursday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/SL NEAR TERM...ARJ/SL SHORT TERM...TRM LONG TERM...TRM AVIATION...ARJ