Marine Weather and Tide Forecast for Indianapolis, IN

FORECAST UPDATE
Issued at 847 AM EDT Mon Apr 28 2025

Forecast is in good shape this morning. An area of mid cloud is moving across the eastern forecast area, but only some high clouds are behind it. Adjusted sky cover to reflect this. Otherwise, just made some tweaks to hourly temperatures as needed.

.SHORT TERM (Today and tonight)...
Issued at 259 AM EDT Mon Apr 28 2025

Current satellite and surface observations show quiet weather conditions across the region with a broken mid-level cloud deck passing through. These clouds have helped to slightly limit diurnal cooling overnight so temperatures were increased by a few degrees.
At the surface, ridging remains in place which has promoted dry weather.

Quiet weather will is expected to continue through most of the period due to the aforementioned surface ridging. However, increasing return flow as surface high pressure shifts east should continue to advect moisture northward late today into tonight. This will lead to increasing cloud cover. Temperatures are also going to warm up very quickly during the day, generally ranging from the upper 70s to low 80s.

Much of tonight should remain dry as forecast soundings suggest top- down saturation will take time overcome a low-level dry airmass. By late tonight, sufficient saturation throughout the column combined with increasing dynamics from a low pressure system moving through the Upper Midwest could support isolated showers or storms. Most guidance shows measurable precipitation holding off until after daybreak Tuesday, but low POPs were added to account for the low potential.

Winds will become gusty late today and tonight as the MSLP gradient tightens and a strong LLJ moves in. Look for increasing winds/clouds to significantly limit diurnal cooling. Lows in the mid-upper 60s tonight will be near normal highs for this of year.

.LONG TERM (Tuesday through Sunday)...
Issued at 259 AM EDT Mon Apr 28 2025

A cold front will track into the region on Tuesday ushering in a period of unsettled weather along with the potential for scattered severe storms. Periodic chances for rain and thunderstorms will persist as the front stalls then lifts back north into Thursday. The passage of a stronger low pressure system will finally force the front to the east of the region by early Friday and bring an end to the threat for rain. After a brief cooldown into the first part of the weekend as an upper trough passes through...ridging aloft and at the surface will bring a return to warm and dry weather into early next week.

Tuesday through Thursday Night

The cold front will move into the area on early Tuesday with convection increasing in coverage into the afternoon as the boundary drops through the forecast area. Model trends continue to favor an earlier impact to storms across central Indiana...perhaps as early as mid to late morning within the moist and unstable airmass over the region. Ample instability with SBCAPEs peaking near 2000 j/kg and sufficient low level moisture with precip water values in excess of 1.5 inches remain supporting factors for more intense convection.
Model soundings showing unidirectional shear and broad instability profiles through the depth of the column suggesting damaging winds as the most likely threat from convection with elevated cores capable of producing large hail. Isolated tornadoes are possible but the lack of more substantial directional shear and overall low level storm relative helicity make it a secondary concern that will likely be predicated on boundary interactions.

The core of the low level jet will lift away to the northeast by early afternoon resulting in a more favorable setup for severe weather from central Ohio northeast into New York. The tail end of the stronger 850mb flow will linger over the forecast area through the afternoon...sufficient for widespread showers and storms but likely serving as a limiting factor to greater intensity and coverage of more intense convection
At this point
anticipate scattered severe storms in a messy convective mode that will likely be multicellular clusters with a few embedded supercells.

Periodic showers and storms will continue as the front stalls near the Ohio River Tuesday night then lifts back north across the entire forecast area by late Wednesday as high pressure passes by to the north over the Great Lakes. Locally heavy rainfall will become the primary concern Tuesday night into Wednesday night focused especially across southern counties with an axis of deeper low level moisture and enhanced forcing in the vicinity of the oscillating boundary. The presence of the high to the north may aid in an extended period of dry weather north of I-70 late Tuesday night through much of Wednesday before the front returns north.

Strengthening low pressure will track into the Great Lakes Thursday with another round of stronger storms impacting the forecast area ahead of the cold front. Abundant cloud cover though will hamper overall instability and consequently convective intensity. The front will clear the region early Friday. Highs near 80 Tuesday will fall back into the 70s Wednesday and Thursday.

Friday through Sunday

An upper trough will swing across the area Friday with the potential for scattered showers during peak heating in the afternoon and early evening. The arrival of high pressure Friday night will set the stage for a dry weekend with mainly clear skies. Highs will only be in the 60s for much of the area Friday and Saturday as the upper trough passes through. The center of the high will move into the Mid Atlantic Saturday night then off the coast Sunday enabling return southerly flow into the Ohio Valley and warmer temperatures. Highs near 70 Sunday will rise to around 80 early next week and possibly warmer than that as next week progresses.

.AVIATION (18Z TAF Issuance)...
Issued at 1255 PM EDT Mon Apr 28 2025

Impacts:

- Some wind gusts up to around 25kt at times through the period

- Non-convective LLWS possible overnight

- Scattered to numerous convection Tuesday

Discussion:

VFR conditions are expected through much of tonight, with high and mid clouds at times.

Winds will gust this afternoon, especially at the western sites.
Wind gusts may diminish some this evening before increasing again overnight into Tuesday with a low level jet moving in.

This jet will also support the potential for non-convective LLWS from 210-230 degrees with winds generally around 40-55 kts at 1500-2500ft.

High uncertainty on the specifics of convection on Tuesday, but scattered to numerous convection is possible at times during the day. MVFR and worse conditions are possible with those.

IND WATCHES/WARNINGS/ADVISORIES
None.