textproduct: Indianapolis

KEY MESSAGES

- Peak wind gusts at 45 to 50 mph across the northern half of central Indiana at times through the first half of today

- Wind chill values near zero early this morning and again tonight and early Tuesday

- Return to seasonable winter temperatures the rest of the week with chances for flurries and light snow Tuesday and Wednesday evenings

SHORT TERM (Today and Tonight)

Issued at 310 AM EST Mon Dec 29 2025

After record warmth on Sunday and a line of convection that produced wind damage across parts of the region...winter has returned with a vengeance early this morning. Westerly winds have been consistently gusting at 45 to 50mph over much of the forecast area since last evening. Temperatures which just a scant 6-8 hours ago were in the mid and upper 60s now range from the mid 20s to lower 30s at 07Z.

Low pressure is in the process of reaching its peak intensity near 980mb over Lake Huron early this morning. The Ohio Valley is now firmly in the backwash of the intense low but a surface trough extending west from the low is set to pivot across the region later this morning into the afternoon before high pressure finally begins to exert its influence tonight.

The strong cold advection in the postfrontal environment was aiding in flurries and narrow bands of light snow showers over central Illinois in the vicinity of the elongated wave aloft to the southwest of the upper low. The ongoing flurries and light snow showers to the west will shift across the northeast half of the forecast area over the next several hours then continue through the morning as the upper wave swings through in tandem with the surface trough. Steepening lapse rates within the boundary layer will aid in coverage as well with snowflakes persisting into the early afternoon before diminishing from the southwest as drier air aloft advects into the region. Expecting little if any impact from the snow with no accumulation as snow remains light and winds continue to efficiently blow flakes around. Flurries may linger over northeast counties until near sunset with dry conditions going forward into tonight.

Sustained winds currently are at 20-30mph across the northern half of the forecast area with gusts routinely hitting 50mph. Further south...gusts have generally been no higher than 40mph. Plan to continue the Wind Advisory over the entire forecast area but may be able to remove southern counties by midday should gusts remain at current levels. As the surface low pulls away to the northeast this afternoon...gusts will begin to decrease with the pressure gradient relaxing.

Finally...have kept cloud coverage high through tonight as model soundings show moisture remaining trapped beneath an inversion. Drier air aloft will work down into the boundary layer by tonight but it may be the predawn hours Tuesday before lower stratus significantly diminishes from the west.

Temps...should fall into the teens and lower 20s after daybreak before subtle recovery occurs later today. Low level thermals support highs largely in the mid 20s. Lows tonight will be in the teens.

Next Weekend

Going into the weekend, high pressure extending from NW Canada into the Ohio Valley slowly shifts eastward; however low level temperatures will be slow to respond as the colder, dense airmass at the surface slowly retreats. Longer range guidance and ensembles continue to show a system developing in the Plains then moving across the Southern CONUS this weekend. Coming out of a blocking northwest flow pattern, it is expected that guidance will not handle this transition well, so low confidence remains in the forecast for next weekend. Trends today have pushed any mention of precip further south, so have trended drier with this weekend's forecast. Keeping the forecast on the drier side with temperatures moderating back above freezing for the weekend.

Beyond next weekend, a progressive weather pattern looks to continue to variable weather conditions and temperatures as each system passes through.

AVIATION (12Z TAF Issuance)

Issued at 601 AM EST Mon Dec 29 2025

Impacts:

- Westerly wind gusts peaking at 35 to 40kts through midday then decreasing slowly into this evening

- Scattered flurries/light snow possible this morning, especially at KLAF

- MVFR ceilings lingering through tonight

Discussion:

MVFR ceilings will remain through much if not all of the forecast period with winds continuing as the primary impact for aviators. Westerly winds gusting at 35 to 40kts at times early this morning will persist through midday along with scattered flurries or light snow showers. Visibilities may briefly lower at times with snow showers.

As the surface pressure gradient relaxes in the afternoon...wind gusts will gradually decrease down to around 20kts by this evening before completely diminishing late tonight. Moisture will remain trapped beneath a boundary layer inversion with stratus likely to linger into tonight.

IND WATCHES/WARNINGS/ADVISORIES

Wind Advisory until 5 PM EST this afternoon for INZ021-028>031- 035>049-051>057-060>065-067>072.