textproduct: Wilmington

SYNOPSIS

A low pressure system moving east through the Great Lakes will bring some snow to the Ohio Valley today, along with colder temperatures. While temperatures will warm up slightly on Tuesday, another system will bring rain and snow on Wednesday, and colder temperatures for the end of the week.

NEAR TERM /THROUGH TONIGHT/

Update (647 AM)... Will continue to see snow showers developing across the area this morning. The intensity of these snow showers has thus far been variable, with one of the more intense showers impacting Delaware County OH (between 5AM and 6AM) with gusty winds and quick accumulations, while other snow showers have not been as strong. Over the next few hours, conditions will remain favorable for a few of the snow showers to be heavy. While road surfaces have thus far been slower to accumulate than grassy areas, there is definitely some refreezing potential on road surfaces as temperatures continue to drop, particularly after initially becoming wet.

Previous discussion (106 AM) > An upper low and weak surface trough are currently in place across the Great Lakes. Water vapor satellite imagery nicely depicts the location of a maxima in vorticity, spinning aloft over northern Illinois as of 100 AM. Well ahead of this feature, a band of snow has been moving east across Indiana, and will move across the ILN forecast area during the 06Z-12Z time frame. The radar depiction of this band has been slightly weakening over the past hour or two, but it will still be capable of producing some light accumulations, particularly on grassy or raised surfaces. However, greater snowfall amounts of up to two inches (as previously indicated by some models) now seem to be unlikely.

Immediately behind this band of snow, there will be a brief period of clearing, before additional moisture and forcing rotates into the area. CAM depictions suggest scattered snow showers will envelop much of the forecast area, with some confidence that the far southern ILN CWA could miss out on any additional snow. Although there will be cold advection, with temperatures continuing to fall, there does not appear to be a single sharp temperature gradient -- keeping the snow showers more scattered than focused. Confidence in truly getting snow squalls is not very high at this point, although there may still be some steep lapse rates and small amounts of CAPE overlapping with the DGZ. At the least, a few heavy snow showers may be capable of producing quick accumulations of a half inch or so, especially as ground conditions will be getting colder.

Gusty westerly winds (25-30 mph) will also occur through the day today -- starting with the initial band of snow, and continuing through afternoon with any additional snow showers.

Precipitation chances should end across much of the area between 18Z-22Z.

SHORT TERM /MONDAY/

High pressure will build into the area tonight, with clearing skies and weakening winds allowing lows to drop into the lower to mid 20s.

Dry conditions are expected to continue on Monday, with highs in the upper 30s to mid 40s.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

Broad surface high pressure will continue to hold its influence across the Ohio Valley Monday night into Tuesday. The location of the surface high will promote return flow, resulting in a mild air mass across the region on Tuesday. Models continue to suggest high temps peaking in the middle 40s to lower 50s. Breezy conditions also expected on Tuesday with gusts of 25-35 MPH possible.

The focus then shifts to the shortwave energy that will dive through the Midwest region Tuesday night into Wednesday. Periods of rainfall can be expected Tuesday night. A cold front will eventually sweep through our fa on Wednesday, resulting in CAA behind the frontal passage. Precip is expected to linger throughout the day Wednesday and perhaps Wednesday night. As thermal profiles begin to cool, snow will mix in before a full transition to snow is expected. Still looking at the potential for at least some light snow accumulations with this particular system, primarily Wednesday night.

A brief lull in activity will ensue Thursday into Thursday night as we remain in-between a series of shortwaves. In the northwesterly flow regime however, cannot rule out some snowflakes falling during the daytime with some moisture transported from the Great Lakes. Temperatures will be notably cooler on Thursday as an Arctic air mass settles into the region, with highs primarily in the 20s.

The next H5 shortwave is expected to move through the Ohio Valley early next weekend, but there is some discrepancy amongst global models on the timing and placement of the trough.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Snow showers will be the main concern for the TAFs through the next 6-9 hours.

Scattered snow showers will continue to move through the area this morning, possibly into the early afternoon. Conditions outside of the snow showers may be VFR, but the snow showers will be capable of MVFR to IFR visibilities, and may also be accompanied by MVFR ceilings and gusty westerly winds of 20-30 knots. Given some uncertainty in where exactly the snow showers will impact, the TEMPO groups in the TAFs are generally MVFR, but this may need to be updated to IFR once it becomes more clear that snow showers would impact a given TAF site.

By late afternoon / early evening, clouds should scatter out to VFR, with winds diminishing to 10 knots or less after 00Z. Some 15-20 knot wind gusts are possible on Monday.

OUTLOOK...MVFR conditions are possible from Wednesday through Thursday.

ILN WATCHES/WARNINGS/ADVISORIES

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