textproduct: Wilmington

SYNOPSIS

A low pressure system will bring rain to the area today, with temperatures remaining above normal. A cold front will move through the area Sunday, bringing snow showers, and much cooler temperatures heading into next week.

NEAR TERM /THROUGH TODAY/

Conditions on this Saturday morning are starting out quite a bit cooler than on Friday, but still above normal for early to mid January. With a fairly amplified upper level pattern still in place, a shortwave is expected to move northeast through the area today, with a very weak surface low tracking on a trajectory perhaps just outside the ILN forecast area to the west and north. This will keep the ILN CWA on the warm side of the system, and as forcing and moisture increase over the region, temperatures will be warm enough to keep precipitation all rain. Precipitation amounts look to remain generally a quarter inch or less, so no significant impacts are expected.

Behind the track of the surface low, a cold front will then move east through the ILN forecast area, ushering in some drier air and westerly winds that may gust into the 20-25 knot range.

SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/

Main concern for Sunday is the potential for snow showers (possibly snow squalls) and gusty winds.

While the initial cold front late Saturday afternoon into Saturday evening will indicate the start of a period of cold advection, it will be a second push of cold air early Sunday morning that may bring some impactful weather to the area. A mid-level low, initially over Wisconsin on Saturday evening, will move southeast into the Ohio Valley by Sunday morning. This low will be associated with a PV anomaly, which will be sliding ESE into the ILN CWA during the 06Z-18Z time frame. Initially late Saturday night, temperatures will be in 30s, but the cold advection should bring temps into the 20s within a couple hours. As this occurs, the boundary layer will become mixed, with steep lapse rates, wind gusts of 20-25 knots (possibly as high as 30 knots), and small amounts of convective instability. While the air mass will not be particularly moist, the forcing and instability appear to be sufficient to produce snow showers, as indicated by the CAM suite.

At the very least, a few heavy snow showers with gusty winds appear likely, and depending on their track some light accumulations of up to an inch are a possibility. There is certainly some chance that legitimate snow squalls could develop -- the PV anomaly, steep lapse rates, and instability that just nudges into the DGZ would support this suggestion. Two limiting factors (lowering confidence in this becoming an impactful snow squall event) are the relatively warm starting point, and the lack of a sharp / well-defined secondary cold front. In terms of timing, the greatest potential for heavy snow showers / snow squalls will be from midnight to 8AM.

By late Sunday morning into Sunday afternoon, the majority of the impactful snow showers should be ending, but light snow / flurries may persist for a while. In addition, a synoptic pressure gradient may bring some additional 20-30 knot gusts to the area, with the strongest winds in central Ohio.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Precipitation chances expected to diminish Sunday night as the mean trough shifts to the east. Surface high pressure will briefly build back in before active weather returns for the majority of the work week. The area of high pressure will be positioned to our south, resulting in return flow on Monday. This will help temperatures trend back to near or just above seasonal normals.

Warming trend will continue into Tuesday, which is expected to be the mildest day in the extended forecast period with highs ranging into the middle 40s to lower 50s. Breezy conditions are likely to develop on Tuesday, with the strongest wind gusts primarily during the afternoon and early evening. Still a bit of range in peak gusts, but probabilities are pretty low for widespread gusts above 40 MPH at this juncture.

While conditions are likely to remain dry during the daylight hours Tuesday, a shortwave will drop down through the Midwest region Tuesday night, resulting in periods of light rain. On Wednesday, a more robust longwave trough will dive southward and provide forcing for more pcpn. Precip will primarily start as rain early in the day, but there will be some snow mixing in by the afternoon and into Wednesday night as thermal profiles cool. Quite a bit of variability in snow accumulations amongst global models, but some accumulations certainly possible, especially Wednesday evening/overnight.

Thursday briefly offers a dry spell before another H5 shortwave ejects through the upper Ohio Valley on Friday. Overall, the pattern looks to remain active heading into next weekend.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

VFR conditions are currently in place at the TAF sites, which should last through the overnight hours.

After 12Z, chances for rain will begin to increase from south to north, and low clouds will also begin to build. Over the course of the morning, aviation conditions will deteriorate, with ceilings dropping to MVFR and then IFR, and MVFR visibilities with rain. These diminished aviation conditions will continue through the afternoon. As this occurs, winds will shift from the northeast to the south, and then eventually to the west by early to mid afternoon, with some westerly wind gusts of around 20 knots expected.

The rain should move out of the area by 00Z, with visibilities improving to VFR, and ceilings improving to VFR with some patchy MVFR still in the area. After 06Z, snow showers are expected to move into the area.

OUTLOOK...Snow showers are expected early Sunday morning, with MVFR to IFR ceilings and visibilities. MVFR conditions are possible again on Wednesday.

ILN WATCHES/WARNINGS/ADVISORIES

OH...None. KY...None. IN...None.