Area Forecast Discussion
Issued by NWS Charleston, WV
Issued by NWS Charleston, WV
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654 FXUS61 KRLX 200635 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 235 AM EDT Fri Sep 20 2024 .SYNOPSIS... A few showers and storms may develop along the mountains this afternoon, but otherwise mostly dry and warm under high pressure. A weak system passes through over the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 235 AM Friday... Surface high pressure slides slightly eastward today, but retaining enough influence over the forecast area that will yield mostly dry weather through the period. Early morning microphysics satellite imagery shows river valley fog underway along the higher terrain and is expected to spread further down into the lowlands before dawn. Any fog development this morning will gradually erode after sunrise and give way to afternoon cumulus, especially along the mountains. Additional growth along the higher terrain may foster isolated showers and storms during peak heating hours. Otherwise, above seasonable temperatures prevail across the Central Appalachians today, with a few areas within the Tri- State area and along the I-64 corridor reaching the low 90s. A slight dip in dew points during the afternoon will bring relative humidity values down into the 30 percent range across the lower elevations. Light surface flow will be present throughout the day, but dry fuels may attempt to stimulate fire weather concerns in areas that have not received measurable precipitation in quite some time. A cold front marching into the Ohio Valley late tonight will stem from a weakening disturbance north of the United States border. Latest model runs depict a delay in showers entering the forecast area within the valid forecast period, so opted to trend back POPs overnight. Otherwise, another decent signal for mountain fog seems plausible for late tonight into early Saturday morning. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... As of 1207 PM Thursday... The pattern to start this weekend will feature a weakening upper- level low across northern New England, a ridge over the Ohio Valley, and another low pressure system developing in the Rockies. Saturday should be dry for the most part, but there is a small chance of a few afternoon pop- up showers over the West Virginia higher elevations with weak shortwave energy passing through the ridge. We only give this a 20-30% chance of occurring. The summer- like heat will be back in full force with highs expected to reach the lower 90s across the lowlands. The more comfortable spots will be in the higher mountain ridges, where afternoon temperatures will be in the 70s-80s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 1208 PM Thursday... A warm front will pass through the area Sunday into Monday as the aforementioned low pressure system, which developed over the Rockies Saturday, tracks eastward. Models are generally dry over our area for Sunday, with rain chances returning Monday as a stronger mid- level wave of energy from the aforementioned low approaches from the northwest. Rain chances will continue into Tuesday as a cold front approaches from the west. Models begin to diverge from Wednesday onward, but we opted to forecast near central guidance, which suggests at least some chances of rain Wednesday and Thursday next week. After starting the week unseasonably hot across the lowlands, temperatures may trend a few degrees below average for mid-to-late week with a potential upper- level low somewhere over the East. Plenty of uncertainty in the long-term forecast, so our confidence remains low. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... As of 140 AM Friday... Nighttime satellite imagery at the time of writing exposed river valley fog taking shape across the higher terrain of West Virginia. This trend is expected to ooze down into the lowlands as the overnight period progresses, impacting most TAF sites outside of BKW. IFR/LIFR were included at most airfields for early Friday morning, then branching out into VFR once more after daybreak. Little to no obstructions are expected during the day Friday, but a few afternoon showers/storms may sprout along the mountains. There is another decent signal for fog late tonight into Saturday morning that will be mentioned in more detail with future issuances. Winds remain light and variable today. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY... FORECAST CONFIDENCE: Low this morning within fog; becoming High after daybreak. ALTERNATE SCENARIOS: Timing and extent of dense fog 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. DATE FRI 09/20/24 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY H L L M M M M L H H H H HTS CONSISTENCY H H L L L L L H H H H H BKW CONSISTENCY H H L L L L H H H H H H EKN CONSISTENCY L L L M M M M L H H H H PKB CONSISTENCY H H L M M M M L H H H H CKB CONSISTENCY H H L M L L L H H H H H AFTER 06Z SATURDAY... IFR conditions possible Saturday and Sunday morning along the higher terrain from river valley fog. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JRM/MEK NEAR TERM...MEK SHORT TERM...JMC LONG TERM...JMC AVIATION...MEK