textproduct: Indianapolis

KEY MESSAGES

- Becoming Mostly clear this evening. Widespread fog possible late tonight into Monday morning, locally dense.

- Mostly Sunny and warmer on Monday.

- Ice Jam development remains a concern this week...as temperatures continue to moderate through 50s to around 60 by middle of next week

- Wind gusts up to 35 mph possible Wednesday

FORECAST UPDATE

Issued at 748 PM EST Sun Feb 15 2026

For the most part, the going forecast remains in good shape. Have hit fog a bit harder in the grids based on latest high resolution guidance, particularly HRRR visibility progs which tend to be fairly reliable in widespread fog situations.

Moist and cool ground, light winds, and clear skies will set the stage for fog development overnight. Confidence is highest across the southern half of the area, where guidance is most consistent, and nearest the axis of high pressure along the Ohio River, where calm winds are most likely - and have gone ahead with a Dense Fog Advisory in this area from midnight to 10 AM Monday, augmenting with an SPS elsewhere.

The advisory may need to be expanded northward depending upon how fog develops as the night wears on, but uncertainty becomes a bit higher with northward extent.

SHORT TERM (This evening through Monday)

Issued at 156 PM EST Sun Feb 15 2026

Surface analysis early this afternoon shows deep low pressure over Mississippi, quickly entering Alabama. High pressure was found over the TX/OK panhandles nosing northeast to IL and NW Indiana. The low to the south was providing cyclonic lower level flow across southern Central Indiana. A large cloud shield was still impacting the SE half of Indiana and was moving southeast quickly as the surface high and subsidence was building from the northwest. Aloft, water vapor shows moderate ridging across the western plains states, with lee side northwest flow building across Illinois and Indiana.

Tonight...

Models suggest the ridging from the west will continue to build across Central Indiana, providing subsidence and mostly clear skies. The broad and narrow high pressure system stretching from TX to northern Indiana will pass across our state tonight. Clear skies and light winds will be the result. Dew point depressions are shown to fall to less than 2F, which should allow for fog development. Also aiding fog development is recent rain and snowmelt, adding moisture to the lower levels. Patchy dense fog will be possible in more rural areas. Look for lows in the middle 30s.

Monday...

After the morning fog breaks, a pleasant, mild day is expected. Models show broad but mild ridging in place over the plains to the Ohio Valley. Meanwhile the surface high will have drifted southeast of Indiana allowing for the return of southerly winds and warm air advection. Forecast soundings show a dry column through the day with unreachable convective temperatures. Thus will expect a mostly sunny day after the fog clears. Given the ongoing warm air advection, high should reach the middle and upper 50s.

LONG TERM (Monday night through Sunday)

Issued at 156 PM EST Sun Feb 15 2026

The hemispheric pattern shows a very active jet stream aloft for this week, with a wave number of 7 as of this morning. This will lead to a strongly meridional jet stream for this upcoming week. Despite the large number of amplified waves, the general pattern will remain similar through the work week, with primarily synoptic ridging over the Appalachian region and troughing over the Inter- Mountain West. The aforementioned waves will push through this broader pattern providing bouts of variable surface conditions throughout the week, but with the influence of ridging to the east of central Indiana, overall temperatures will remain well above normal through the long term.

The first of these amplified troughs will reach the western coast late today into Monday, shifting the general flow southwesterly for Tuesday and Wednesday. Initially, temperatures will be slow to respond with frontogenetical forcing keeping conditions in the 50s under cloud cover for Tuesday, but as the warm front lifts northward, temperatures will quickly rise on Wednesday. The record high for Wednesday is 66, of which there is high potential to reach or even break depending on how quickly central Indiana can reach an uninhibited warm sector. A second wave within the broader flow will keep conditions warm for Thursday before weak CAA "cools" temperatures down to end the work week. Despite the cooling, temperatures will still stay well above normal for Friday and this weekend.

In regards to precipitation chances, there will be multiple possibilities. The first of which will be late Tuesday night into Wednesday morning with the passage of the prior mentioned warm front. Any rain with this should be light with the SW flow coming off a drier airmass over the southern Plains. As the low level disturbance nears later on Wednesday, there could be enough forcing to break through a low level convective inhibition layer and for isolated to scattered thunderstorms to develop. Confidence in this occurring is low, but the possibility cannot be ruled out. The greater threat for precipitation will be on Thursday, as moisture return increases within a shift to southerly flow from the Gulf. There is ensemble variability in surface low track with both systems, providing enough uncertainty to keep PoPs below 70% at this time, but this could increase in the coming days if consistency increases. Strong flow aloft along with modest instability will provide the potential for severe conditions within any thunderstorms Wednesday or Thursday, but we are still too far out to pinpoint any specifics.

After Thursday's system, conflicting forcing will work to push the synoptic flow more towards zonal, of which is leading to high uncertainty in surface conditions for the weekend, especially regarding precipitation. General consensus is for temperatures to remain near to above normal, but specifics will depend on smaller, low level disturbances in the wake of the more amplified pattern earlier in the week, and how far east the western trough pushes into the central CONUS.

AVIATION (00Z TAF Issuance)

Issued at 618 PM EST Sun Feb 15 2026

Impacts:

- Widespread fog expected tonight with areas of dense fog producing LIFR or worse conditions

Discussion:

An axis of high pressure along the Ohio River overnight will allow for light to calm winds and clear skies, which will promote the development of fog from south to north across the area in the 05-09Z time frame. At least periods of LIFR or worse conditions are likely in the couple hours either side of daybreak Monday, with visibilities 1/2SM or less and vertical visibility limited to a couple hundred feet.

This fog will gradually mix out in typical diurnal fashion Monday morning, with some low cloud lingering until VFR conditions return fully by midday.

Winds will be light and variable to calm overnight, becoming southwesterly during the day Monday. Gusts of 17-20KT will be possible.

IND WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory from midnight tonight to 10 AM EST Monday for INZ051>057-060>065-067>072.