835 FXUS61 KRLX 260239 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 1039 PM EDT Wed Aug 25 2021 .SYNOPSIS... Hefty upper level disturbance keeps showers and storms going tonight. High pressure in control Thursday with afternoon shower activity possible. Upper level ridge builds Friday into the weekend. && .NEAR TERM /THROUGH THURSDAY/... As of 1038 PM Wednesday... Precipitation has mainly tapered off across the region, but a shortwave trough across OH and any lingering outflow boundaries may allow for an isolated shower/storm overnight in these warm and muggy conditions. However, have removed PoPs from the forecast for overnight as confidence is low in location and timing of any activity if anything is even able to develop. Otherwise, main concern overnight will be the potential of fog, which could become dense in some areas, especially locations that received heavy rainfall from earlier today. While some mid level cloud cover will likely linger for most of the night due to the aforementioned shortwave trough, the recent precipitation and small dewpoint depression should still favor the development of fog in many areas. As of 629 PM Wednesday... Temperatures have fallen quickly this evening in the wake of the convection that has occurred. As a result, the Heat Advisory from today has been cancelled as heat index values have fallen below criteria. As of 447 PM Wednesday... Made a quick update to PoPs as latest radar imagery shows a line of showers and storms pushing eastward across the region. The overall severe risk is low with this activity, but an isolated strong gust can't be completely ruled out given the high DCAPE values in place. However, this threat appears to be quickly diminishing based on recent trends which shows a lot of this activity weakening. As of 210 PM Wednesday... A compact but strong upper level shortwave will arrive to the OH River by 00Z. With ample moisture, expect showers and storms continuing tonight. The strongest showers or storms could produce heavy rain. Localized water issues can not be ruled out tonight. Conditions should improve towards the early hours Thursday morning when shower activity is expected to end. Periods of dense fog are possible over areas that received rain this afternoon and early tonight. Any fog or low stratus will dissipate by 13Z Thursday. A strong mid-level ridge extending from the central plains through the Ohio Valley will continue to provide hot and humid conditions on Thursday. A daily chance of storms continues in this pattern, with more confidence along the mountains. Lows tonight will be above normal, generally around 70 degrees. Highs on Thursday should range from the upper 80s lowlands, into the mid 70s highest elevations of our northeast mountains. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 230 PM Wednesday... An upper level ridge strengthens over the eastern US late this week and then persists into the weekend. Continued ridging over the area will allow temperatures to remain hot with highs in the upper 80s to low 90s in the lowlands, and mid 70s to upper 80s in the mountains. In the lowlands, heat indices are projected to rise into the mid to upper 90s during the afternoons, which is just shy of advisory criteria for now. While mainly diurnally driven showers and storms are expected each day, shortwave energy crossing through the area may provide additional support for shower or storm development. Precipitable water values in the 1.5-2" range indicate heavy downpours may be possible within any showers or storms. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 130 PM Wednesday... Ridging remains in control of the area through Sunday, but begins to degrade early next week as an upper level trough develops to the north. The trough is projected to deepen into the eastern US and will push a cold front into the area by mid week. Diurnally driven shower and storm activity is expected for Sunday, then shower and storm chances increase into the middle of the work week as the cold front approaches and then moves through the area. After a hot start to the long term period, temperatures are expected to gradually lower back towards normal during the work week. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... As of 808 PM Wednesday... Scattered showers and thunderstorms will continue to taper off with the loss of daytime heating with VFR conditions to start the TAF period at most terminals, but conditions will be IFR at KBKW due to a cluster of showers and storms from earlier have brought VSBY values down significantly. Eventually, fog is expected to develop overnight and conditions are expected to deteriorate area-wide, especially at terminals that received heavy rainfall from the convection earlier today. Depending on how much cloud cover can decrease, fog could become dense in some places with a prolonged period of IFR/LIFR conditions possible overnight. Any fog across the region should dissipate around 12Z-13Z Thursday, and conditions should mostly return to VFR across the region on Thursday afternoon. However, isolated to scattered showers and thunderstorms will be possible during the day as an upper disturbance crosses the area. Thus, brief flight restrictions will be possible if any thunderstorms directly impact any terminals. Most of the thunderstorm activity should generally taper off by Thursday evening, but a few storms may linger through the end of the period due to the humid conditions that will remain in place. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Location, duration, and intensity of valley fog forming overnight tonight may vary from forecast, depending on rain from earlier today and potential clearing of some cloud cover overnight. 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 THU 08/26/21 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H L M M M M M HTS CONSISTENCY H H H H H H H L M L M L BKW CONSISTENCY H H H H H H M M M M M M EKN CONSISTENCY H H H H H H L L L M M M PKB CONSISTENCY H H H M H H L M M M M M CKB CONSISTENCY H H H H H H M L L M L L AFTER 00Z FRIDAY... IFR valley fog possible each morning through this weekend. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...ARJ/JLB NEAR TERM...ARJ/RG SHORT TERM...JLB LONG TERM...JLB AVIATION...RG