927 FXUS61 KRLX 061408 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 1008 AM EDT Thu Jul 6 2023 .SYNOPSIS... Prefrontal trough this afternoon and cold front overnight into Friday bring unsettled weather. Another cold front brings more unsettled weather late Saturday through Sunday night. && .NEAR TERM /THROUGH TONIGHT/... As of 1008 AM Thursday... Temperatures and sky conditions remain on track with the inherited forecast this morning so little to no changes were necessary. As of 600 AM Thursday... No changes needed at this time. Fog remained patchy/thin enough this morning, so no morning commute highlights required. As of 145 AM Thursday... Patchy fog will be possible, primarily confined to the valleys this morning, although approaching upper level cloudiness associated with a prefrontal trough will put a timer on developing anything across our western counties. Any fog that does develop dissipates through 8- 9AM. A few elevated showers are noted across SE OH early this morning, these will continue to shift off to the NNE brushing by Vinton and Perry County. Otherwise, dry conditions are expected for the remainder of the overnight and well into the daytime hours as temperatures across the lowlands rise to near 90. This afternoon some diurnal convection will be possible near the higher terrain with additional showers and storms forming in advance of a prefrontal trough across SE OH, NE KY and W WV. Additional showers and storms will be possible as a cold front begins working into the region overnight. Overall, forcing with these features is relatively weak, although precipitable water values pooling ahead of the cold front edge up toward 2 inches with fairly deep convective warm cloud depths. This should yield some efficient rainfall production in any convective cores with some localized high water issues possible. Weak column flow limits deep layer shear to 10-15KTs, but this will also make for rather slow storm motions, especially for the more diurnally driven storms. Some patchy fog will be possible ahead of the cold front heading into Friday morning, especially where any measurable rain occurs today/this evening. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... As of 310 AM Thursday... Any fog dissipates first thing Friday morning, and showers and thunderstorms refiring Friday afternoon will be most numerous in the mountains, as a cold front pushes east across the area. However, as the mid-upper level short wave trough driving the cold front through the area lifts through the upper Ohio Valley, meager forcing, light mid level flow and drying of all but the low levels should preclude both severe and excessive rainfall threats. With weak high pressure sailing by to the north, light flow surface and aloft is likely to lead to valley fog overnight Friday night into early Saturday morning, especially where it rains on Friday. How long dry weather lats into Saturday depends upon the timing of the next cold front approaching from the west, but a weak mid-level short wave trough ahead of the main short wave trough driving the cold front toward the area, should aid in at least afternoon pop-up showers and thunderstorms. The threat for strong, heavy storms may increase a bit along the western flank of the forecast area late Saturday, as the main short wave trough approaches, yielding a modest increase in flow/shear, and PW values. Central guidance reflects temperatures settling back to normal for Friday and Friday night as the cold front pushes east, and then a bit above normal ahead of the next cold front on Saturday. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 310 AM Thursday... A cold front crosses Sunday night into Monday, as mid-upper level short wave troughs cross Saturday night and again Sunday night. The timing of the associated mid-level forcing is at odds with diurnal timing, with unsettled weather possible anytime Saturday night into Monday. The environment during this time will feature light flow and shear, and ample mid-summer moisture with dew points north of 70F and PW values north of 1.5 inches, perhaps as high as 1.8 inches. This spells a low severe threat but the potential for heavy downpours, and the threat for localized flash flooding. The weather pattern settles into a more diurnally driven pop-up shower/thunderstorm pattern heading into the middle of the next work week, as the area resides along the southern edge of a mid-upper level cyclonic circulation, its center wobbling about the James Bay, Canada, area. Central guidance reflects suppressed high temperatures Sunday and Monday amid clouds and showers, recovering to at least normal heading into midweek. Lows are forecast to be near to slightly below normal through the period. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... As of 600 AM Thursday... Patchy fog dissipates through 13Z this morning. Low level moisture may briefly lift into a MVFR deck for an hour or two before convective cloud bases increase to VFR. Mostly dry conditions are expected through early this afternoon - thereafter pop-up convection is expected near the mountains with additional convection approaching from the west ahead of a pre-frontal trough. Best chances for terminal impacts with this activity will be PKB and HTS, but still too far out/too low confidence for any TEMPO/PROB30 TS groups. Will code SHRA VCTS with minimal impacts to visibility for now, but if a convective core crosses a field could reasonably expect a brief period of IFR visibility in locally heavy rainfall. Activity settles down overhead even as a trailing cold front approaches from the west. Ahead of this feature pooling of moisture may yield some IFR ceilings or patchy fog heading into daybreak Friday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Flight category may temporarily lower if a shower or storm develops at a terminal 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 L M H H H H H H H H H HTS CONSISTENCY H M M H H H H H H H H H BKW CONSISTENCY H M M H H H H H H H H H EKN CONSISTENCY L L M H H H H H H H H H PKB CONSISTENCY H M M H H H H H H H H H CKB CONSISTENCY H M M H H H H H H H H H AFTER 12Z FRIDAY... IFR valley fog possible early Saturday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/JP NEAR TERM...JP/MEK SHORT TERM...TRM LONG TERM...TRM AVIATION...JP