Area Forecast Discussion
Issued by NWS Wilmington, OH
Issued by NWS Wilmington, OH
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
385 FXUS61 KILN 181716 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 116 PM EDT Wed Sep 18 2024 .SYNOPSIS... An upper level low pressure system over the southern Appalachians will slowly migrate to the east today. This system will offer clouds and perhaps a sprinkle or light rain shower. High pressure and dry weather will then persist into the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 18.12Z sounding had fairly decent mid and high level moisture - and this is manifested in areas of mid cloud/cirrus that are on a slow diminishing trend per visible satellite loop this morning. With increased - but shallow - low level moisture over previous days, expect some cumulus to develop later this morning or early this afternoon amidst light easterly/northeasterly low level flow. Some residual showers are working southwestward across southeast Ohio/West Virginia around the departing upper trough/vertically stacked cyclone to our southeast, a few sprinkles or very light showers may still clip the Scioto Valley and northeast Kentucky. In addition, forecast soundings for late this afternoon indicated some very weak instability, and in combination with some semblance of cyclonic flow/upper troughing, a number of CAMs continue to show a couple of isolated updrafts trying to form later this afternoon into this evening, in no particular or favored location. Given concerns of low level moisture mixing out per ongoing drought conditions, confidence in these forming is not high enough to mention, and may be tied to models continued overforecast of low level moisture in recent weeks. Bumped up afternoon high temps just a bit based on low level thermals on morning sounding under a mix of sun and clouds. Rest of forecast on track. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Mid level low over the southern Appalachians to open up and track east overnight into Thursday. Clouds decrease this evening with skies becoming mostly clear. This will result in more favorable radiational cooling conditions leading to lows dipping into the upper 50s to the lower 60s. With a light low level northeast flow and mainly clear skies - some fog and stratus development will be possible. The best threat for stratus looks to be over the northeast counties but there is still is a fair amount of uncertainty on placement. A vort lobe rotating around the western periphery of mid level trof and an axis of marginal instability may result in the threat for a shower or thunderstorm east of ILN/s area Thursday afternoon. This activity should remain well east of ILN/s area with partly cloudy to mostly sunny sky conditions. Sunshine will aid warm temperatures reaching highs in the mid and upper 80s. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... Period starts under high pressure with dry weather expected to persist from Thursday night through Sunday. Unsettled weather begins Sunday night with the arrival of mid level short wave energy and moisture convergence ahead of a boundary, bringing a chance of showers and a few thunderstorms to northwestern locations. The threat for showers and storms spreads across the area Monday and Tuesday as additional short waves and moisture advection coincide over the Ohio Valley. Severe weather threat is hard to determine at this point but any measurable rainfall will notable during our drought. Temperatures begin hot with highs around 90 Friday and Saturday. Potential clouds and precip should help curtail readings a bit for the rest of the long term, with highs in the mid and upper 80s Sunday and Monday, and the upper 70s to low 80s Tuesday. && .AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... Scattered to locally broken VFR cumulus continues to develop early this afternoon, but expect cloud bases to lift a little more through the day due to heating so no MVFR potential with these clouds even if they go broken/ceiling for a brief period. Most will be scattered in coverage. Light northeast winds will sometimes go variable in direction due to weak pressure gradient. Winds should go calm or light/variable before sunset with vast majority of cumulus dissipating. With clear/mostly clear skies tonight, think valley fog will develop and affect LUK as it usually does on clear/calm autumn nights, and have TEMPO for IFR visibility there. A separate signal for more widespread / areal fog is showing up across the area. Confidence is low in how this may manifest, but felt confident enough to bring some MVFR visibilities via TEMPO groups into all TAF sites between 08-12Z. Coverage and favored location is not high, and future forecasts may need to consider lower visibility based on observational trends. Background setup (clear skies, longer nights, light northeast wind, shallow moisture recently having moved into the area) makes areas of fog (or perhaps low clouds) more probable later tonight. Any remaining fog should lift/mix out on Thursday morning with more scattered cumulus by 18Z, and continued light northeast or easterly winds. OUTLOOK...No significant weather expected. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...AR NEAR TERM...Binau SHORT TERM...AR LONG TERM...Coniglio AVIATION...Binau