Area Forecast Discussion
Issued by NWS Charleston, WV
Issued by NWS Charleston, WV
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
489 FXUS61 KRLX 220710 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 310 AM EDT Sun Sep 22 2024 .SYNOPSIS... Dry and hot today. Unsettled weather returns late tonight into the new work week, bringing beneficial rainfall back into the area. && .NEAR TERM /THROUGH TONIGHT/... As of 215 AM Sunday... Satellite imagery early this morning reveals river valley fog growing in coverage and intensity across northeast West Virginia and along the southern Ohio River Valley. These two areas were noted to have received measurable rainfall on Saturday from a cold front and will likely festering through the predawn hours into daybreak this morning. A Dense Fog Advisory could be warranted later on this morning if half mile to quarter mile visibilities continue down into our more populated areas. The frontal boundary planted directly over the forecast area early this morning is progged to shift slightly northward today as a warm front. This will place the Central Appalachians in the warm sector of an encroaching disturbance slated to arrive late tonight into early Monday morning. In the meantime, afternoon temperatures in the Tri-State area and into the central lowlands will once again topple over the 90 degree mark. Minimum relative humidity values will bottom out into the 20 to 30 percent range during peak heating hours this afternoon in the lower elevations and down into the 30 to 40 percent range along the mountains and southern coalfields. This will be the last day through the foreseeable future for these low RH values as low level moisture becomes present over the next several days. We should lack the wind component today when it comes to fire weather concerns. A low pressure system tracking through the Ohio Valley today will invade the forecast area by dusk this evening. Clouds will first arrive this evening, followed by a line of broken showers and thunderstorms late tonight into the overnight hours. This marks the revival of unsettled weather for the start of the new work week and brings beneficial rainfall to the area. Within this portion of the forecast, QPF totals range from a few hundredths to a tenth of an inch across southeast Ohio and eastern Kentucky, where POPs will first arrive overnight. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... As of 305 AM Sunday... A moist airmass is forecast to be in place Monday through Tuesday as the region sits in the open warm sector of a slow moving surface low transiting the Mid-West. Diffluent flow aloft should allow for both nocturnal elevated convection as well as diurnally enhanced surface based storms Monday. Initially, deep layer shear will be on the weaker so not expecting too much in the way of storm organization Monday. The main threat with any activity will be locally heavy downpours. While any rain would be largely beneficial, could see some localized drainage issues over built up areas should one of these downpours dwell too long. Deep layer flow increases on Tuesday in response to the parent upper trough approaching the region. Contingent on diurnal destabilization could see a severe threat emerge for Tuesday afternoon with locally damaging winds, and perhaps a low end tornado threat as the primary hazards, most likely focused from the Metro Valley down the Tug Fork, although confidence is low this far out. Cold frontal passage is then expected Wednesday. At present this looks to occur relatively early in the day and not yield as much of a chance to destabilize diurnally. Ensemble guidance is reasonably confident in the combination of this activity to produce widespread beneficial rain, which should help take the edge off very dry unsheltered fine fuels, even if it won`t put much of a dent in our rainfall deficit. Interquartile 72hr amounts ending Thursday morning range from around half an inch to near 2 inches, highest in the northeast with our current deterministic forecast generally falling in this range. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... As of 305 AM Sunday... Confidence is low for the the long term period with a wide range in model solutions. Generally most confident in amplification of the northern stream that would help to shunt any potential tropical moisture from development in the Gulf of Mexico east of us keeping our region mainly dry, but a non-trivial number of ensemble members are subdued enough with this feature to allow tropical moisture this far west. This is reflected in a significant interquartile spread in QPF values for the latter half of the week. For the deterministic forecast will continue to defer to central guidance advertising some lower end PoPs each day into next weekend for now. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... As of 143 AM Sunday... River valley fog has grown more prevalent early this morning across northern West Virginia and parts of the Ohio Valley. At the time of writing, PKB had just joined CKB and EKN down into IFR. Forecast soundings show just enough of a breeze in the lower levels at CRW and HTS that will cause a delay in fog production for a few more hours before IFR or worse conditions encroach on their airfields. For BKW, an area of low level stratus was developing to their north and could spread some MVFR CIGs down into the area before daybreak. The combination of low vsbys/ceilings will gradually improve after sunrise, returning all sites to VFR for the daytime hours. Ceilings will begin to lower late Sunday night into early Monday morning with the encroachment of a disturbance that will open up the new work week. Winds will light and variable through the TAF period. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY... FORECAST CONFIDENCE: Low this morning, then becoming Medium/High. ALTERNATE SCENARIOS: Timing and location of overnight fog/stratus may vary from the 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 SUN 09/22/24 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY L M M M M L H H H H H H HTS CONSISTENCY L L L L H L H H H H H H BKW CONSISTENCY H L L L H H H H H H H H EKN CONSISTENCY M M M M M L H H H H H H PKB CONSISTENCY L L L L M L H H H H H H CKB CONSISTENCY M H H H H L M H H H H H AFTER 06Z MONDAY... Brief IFR possible in any heavier showers and thunderstorms Monday afternoon through early Wednesday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Dense Fog Advisory until 10 AM EDT this morning for WVZ009>011- 017>020-028>032-039-040-521>526. OH...Dense Fog Advisory until 10 AM EDT this morning for OHZ076. KY...None. VA...None. && $$ SYNOPSIS...MEK/JP NEAR TERM...MEK SHORT TERM...JP LONG TERM...JP AVIATION...MEK