Area Forecast Discussion
Issued by NWS Charleston, WV
Issued by NWS Charleston, WV
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581 FXUS61 KRLX 231821 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 221 PM EDT Sun Jun 23 2024 .SYNOPSIS... A cold front brings showers and thunderstorms into this evening, with the front crossing tonight. More seasonable air can be expected behind the front on Monday. Heating up again midweek. && .NEAR TERM /THROUGH MONDAY/... As of 215 PM Sunday... After an initial band of showers fell apart as it entered the area this morning, a new band of showers fired up just west of, and slicing into northwest portions of, the forecast area early this afternoon, ahead of a cold front and beneath a broad, loosely defined mid level short wave trough. While there is limited opportunity for surface heating due to cloud cover, temperatures were off to a high start this morning, and were already at or near convective temperatures, in the mid to upper 80s, across much of the middle Ohio valley. SPC analysis showed modest CAPE of under a KJ/kg over much of the forecast area, but as high as 1.5 KJ/kg along the western flank, and 2 KJ/kg just upstream, where the convection was starting to fire up. This and deep layer bulk shear to 30 kts or so should be just enough for strong to marginally severe thunderstorm wind gusts, especially in clusters or short line segments. SPC has maintained the slight risk of severe thunderstorms for the middle Ohio Valley, with a marginal risk elsewhere. While rainfall rates have not been high at all yet, PW values in the 1.75 to 2 inch range should lead to heavy downpours as storms intensify this afternoon. WPC continues the marginal risk for locally excessive rainfall for the area. Showers and thunderstorms will gradually decrease in intensity and coverage as they move east across the mountains tonight. Once the cold front crosses, low clouds may form, mainly in and near the mountains, but there should be enough gradient low level flow to keep fog formation limited, and the clouds will mix into an afternoon cumulus field atop the deepening mixing layer on Monday. After a warm evening ahead of the front, save for wet-bulb cooling, lows Monday morning will be perceptibly lower across northwest portions of the forecast area, and slightly lower southeast, compared with this notably warm morning. Monday brings relief from the heat with highs down around normal. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 220 PM Sunday... Tuesday looks to remain mainly dry across the area, although an isolated shower or storm cannot be completely ruled out from any passing disturbance, overall, we should be stable enough to prevent much of anything from developing. Temperatures on Tuesday will likely top out in the lower 90s once again for many lowland locations. By Wednesday, showers and storms will be on the increase once again, possibly in multiple rounds, with one round possible in the morning, and another later in the day as an upper trough and cold front start to move through the area. Some of these storms could be strong to severe, and will contain heavy downpours. && .LONG TERM /THURSDAY THROUGH SATURDAY/... As of 1148 AM Sunday... Frontal boundary and upper trough will move east of the area late Wednesday night or early Thursday, with high pressure building into the region behind it. This should usher in a brief period of cooler and drier weather for Thursday. By Friday into the weekend, heat returns, as southerly flow increases out ahead of the next system, which will move into the area over the weekend, with additional rounds of showers and storms. A bit early to say for sure, but heat headlines may be needed during this time period. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... As of 215 PM Sunday... Some of the showers developing just west of the area ahead of a cold front early this afternoon will grow into thunderstorms that could be strong and heavy as the cross the area later this afternoon. The best chance for a strong, heavy thunderstorm will be 20-24Z and mainly over the middle Ohio Valley, versus the central Appalchians. Showers and thunderstorms should decrease in strength and coverage tonight. MVFR stratocu is likely to settle in east of the Ohio River overnight, and may lower to IFR in the mountains before dawn Monday, before lifting and breaking up into a cumulus field later Monday morning. Visibility may lower to MVFR in and near the mountains toward dawn Monday, before improving after sunrise. Gusty southwest surface flow outside thunderstorms this afternoon will become light west behind the cold front tonight, and then light northwest on Monday. Light to moderate southwest flow aloft this afternoon will become light to moderate northwest behind the front aloft tonight, and then light north to northwest on Monday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing and intensity of showers and thunderstorms could vary, and amendments may be needed for brief IFR conditions. 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 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H M H H H M L HTS CONSISTENCY H H H M H H H H H H H H BKW CONSISTENCY H H H H H H H H H H M H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H M M H H H H H H H H CKB CONSISTENCY H H H M M H M M M H H H AFTER 18Z MONDAY... IFR possible in fog overnight Monday night into early Tuesday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM SHORT TERM...SL LONG TERM...SL AVIATION...TRM