textproduct: Wilmington

WHAT HAS CHANGED

Minor adjustments continue to be made for the snowfall expected Tuesday.

KEY MESSAGES

1) Another bitter morning with some very light snow possible today.

2) Accumulating snow across southeast Indiana, southern Ohio, and northern Kentucky Tuesday into Tuesday evening.

3) Clipper moving across the area Thursday and Friday. Bitterly cold temperatures return for the weekend.

DISCUSSION

KEY MESSAGE 1) Another bitter morning with some very light snow possible today.

As clouds slowly creep in from the west this morning, areas that remained clear most of the night have seen temperatures drop in the single digits to below zero. Meanwhile, areas that saw temperatures drop early in the overnight are now beginning to see temperatures rebound with the clouds moving in. The weak system approaching the area provides southwesterly flow, which will help temperatures rise a bit more today, however, still expecting the majority of the area to remain below freezing.

A stretched out shortwave moves across the area today, with a north to south aligned band of light snow occurring as it does so. Across the southern portions of the area (a line from Richmond, IN -> Wilmington, OH -> Chillicothe, OH and south), moisture is bit lackluster into the DGZ and lift is weaker compared to the north. Therefore have focused the highest PoPs across northern portions of the area, along with the light accumulations up to a half inch. As the main band moves away during the late afternoon and early evening, moisture into the DGZ decreases. Weak lift may support a period of freezing drizzle for a couple of hours. Opted to not include a mention in the forecast at this time given the low potential, but it will be something to watch for as the day progresses.

KEY MESSAGE 2) Accumulating snow across southeast Indiana, southern Ohio, and northern Kentucky Tuesday into Tuesday evening.

Much of the guidance is now in fairly good agreement that a locally enhanced snowfall event is probable across a portion of the area starting late Tuesday morning, ending during the evening hours. NBM probabilities are now 30-50% for 3" or greater, primarily from eastern/southeast Indiana into southwest/southern Ohio and northern Kentucky. As a result, accumulations were increased across this area with 2-3" of snow now forecast. Chances remain much less to the north from Dayton to Columbus, but some minor accumulations up to an inch are advertised.

Confidence has increased with the snowfall accumulations, however, the forecast remains very sensitive to the mesoscale banding that is expected to develop late Tuesday morning. As the shortwave moves into the lower Ohio Valley, lift through frontogenesis increases locally. This means that instead of seeing the snow band move into the area from Iowa/Illinois, the band of snow may visually develop and expand primarily over the Wilmington and Indianapolis CWAs. Forecast soundings show some of the best forcing within the DGZ, favoring efficient snowfall rates where the bands develop. While likely localized to where the best banding forms, warning criteria snow (4" in these locations) is on the table given the unique scenario over the local area. No headline decisions planned for this shift, but will continue to message the potential in the HWO. Additional confidence with another set of CAM guidance will help drive headline decisions in future shifts. Confidence in where the highest snow may fall likely will not occur until the banding develops Tuesday morning.

Snow pulls away to the southeast during the evening hours with temperatures dropping into the lower 20s and teens through Tuesday night and into Wednesday morning.

KEY MESSAGE 3) Clipper moving across the area Thursday and Friday. Bitterly cold temperatures return for the weekend.

The Thursday night/Friday system is still expected, but guidance continues to waffle around the exact position of the surface low and better upper level forcing. Trends overall have been for the system to be a little farther to the northeast of the region, reducing probabilities for snowfall accumulations. With the latest NBM, chances for 3" of snow or more are highest across the Columbus area, but they have dropped from 30% to around 10% over the last few cycles of the NBM.

Even if the snow does not come to fruition, the next blast of bitterly cold temperatures is of higher confidence. While brief, temperatures in the single digits along with wind chills below zero are once again likely. It is nearly a week away, but it does appear as though temperatures may quickly rebound into the following work week.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Delayed the onset of MVFR restrictions by a few hours from the previous TAFs with satellite showing VFR CIGs will arrive ahead of the better chances for MVFR. Removed the potential for overnight visibility restrictions with recent guidance trending more optimistic for higher visibility.

As MVFR restrictions move in throughout the morning, a band of light snow will move west to east across the area, with PROB30s for this and reduced visibility mentioned for DAY/LCK/CMH. Chances are a bit lower toward ILN/CVG/LUK. Expect MVFR restrictions to remain through much of the TAF period, but some breaks to VFR are possible late. Winds are generally southwest and less than 10 knots for much of the period, but a gradual shift toward more westerly winds is expected near the end of the TAF.

OUTLOOK...MVFR to IFR ceilings will continue into Tuesday night. MVFR to IFR visibilities are possible Tuesday. MVFR CIGs linger into Wednesday.

ILN WATCHES/WARNINGS/ADVISORIES

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