Area Forecast Discussion
Issued by NWS Charleston, WV
Issued by NWS Charleston, WV
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247 FXUS61 KRLX 220457 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 1257 AM EDT Sat Jun 22 2024 .SYNOPSIS... The heat wave continues today courtesy of a broad upper level ridge. A cold front crosses Sunday night, bringing showers and storms to the area, and an end to the heat wave. && .NEAR TERM /THROUGH TONIGHT/... As of 1255 AM Saturday... A ridge of high pressure will continue to provide above normal temperatures across the area. Although the airports have not been hitting Heat Advisory criteria, some of the warmer valleys have been, especially in cities. Therefore, will continue the Heat Advisory for the lowlands. Models indicating a small chance of afternoon thunderstorms along the mountains. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 255 PM Friday... The upper level ridge associated with the current heat wave gets shunted off to the deep south/southwestern U.S. this weekend, as a mid-upper level short wave trough approaches. Increasing forcing and modest 0-6 km bulk shear of 20-30kts acting on the afternoon instability amid the hot, humid air mass, with CAPE building to 2-3 KJ/kg in an axis ahead of the front, leads to the potential for strong to marginally severe thunderstorms Sunday afternoon and evening across the lowlands. The severe threat decreases as convection crosses the mountains overnight Sunday night, as instability decreases. Showers and thunderstorms will have modest motion so, while PW values up around two inches could result in locally excessive downpours, widespread high water instances are not expected. Central guidance evinces a very arm and humid Saturday night, with rising temperatures on Sunday intercepted by increasing clouds and developing convection, soon enough to preclude extending the heat advisory into Sunday. Lows Monday morning will be perceptibly lower across northwest portions of the forecast area, slightly lower southeast, compared with Sunday morning. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 255 PM Friday... A cold front exits the forecast area Monday morning, bringing an end to the prolonged heat wave. Its trailing positively-tilted short wave trough, extending southwestward from a mid-upper level low crossing northern New York and New England Monday, crosses Monday morning and midday. Showers will be limited to the mountains by dawn Monday, where there may still also be a thunderstorm, depending upon the timing of the front. This precipitation will gradually dissipate during the day, with little if any opportunity for a diurnal resurgence, as cooler and much drier air advects in beneath the crossing short wave trough, with a strong post- frontal/subsidence inversion. High pressure builds in Monday afternoon, crosses Monday night, and then exits Tuesday morning. This will bring about a clear, comfortably cool night Monday night, with calm conditions allowing valley fog to form. The upper level ridge associated with the current heat wave remains shunted off to the deep south/southwestern U.S. next week, allowing west to northwest mid-upper level flow with embedded short wave troughs/convective complexes over the area. With low level south to southwest gradient flow behind the exiting high feeding increasing warmth and moisture back into the area, showers and thunderstorms become possible Tuesday night, and then remain so until a deep enough short wave trough pushes a cold front through the area Wednesday night or Thursday. Central guidance reflects temperatures and dew points lower by several degrees compared with those during the current heat wave, but enough to bring perceptible relief. The heat returns Tuesday and Wednesday of next week as heights rebuild, but with the ridging off to the southwest of the area, it will not be as hot as this week. The heat will also be not as persistent, given the passage of cold front later in the week. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... As of 1255 AM Saturday... Some patchy fog can be expected early this morning, mainly in mountain river valleys. There is also a small chance of afternoon thunderstorms along the mountains, but chances are too small to include in the TAFs. Outside of these 2 items, expect VFR conditions. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY... FORECAST CONFIDENCE: Medium with fog, otherwise high. ALTERNATE SCENARIOS: Timing and density of fog could vary. 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 SAT 06/22/24 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10 CRW CONSISTENCY H H H H M L M M L H H H HTS CONSISTENCY H H H H H M L M H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H M L L M M L L H H H PKB CONSISTENCY H H H H M L L M H H H H CKB CONSISTENCY H H M M M L M M H H H H AFTER 06Z SUNDAY... No widespread IFR conditions are expected at this time. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Heat Advisory until 8 PM EDT this evening for WVZ005>011- 013>020-024>032-039-040. OH...Heat Advisory until 8 PM EDT this evening for OHZ066-067-075- 076-083>087. KY...Heat Advisory until 8 PM EDT this evening for KYZ101>103-105. VA...None. && $$ SYNOPSIS...RPY/TRM NEAR TERM...RPY SHORT TERM...TRM LONG TERM...TRM AVIATION...RPY