textproduct: Indianapolis

KEY MESSAGES

- Pleasant and dry through Monday Morning.

- Severe thunderstorms possible from mid afternoon Monday into Monday night

- Cooler temperatures expected Tuesday through Saturday.

DISCUSSION (This evening through Saturday)

Issued at 131 PM EDT Sat Apr 25 2026

Surface analysis this morning shows moderate high pressure in place over WI and Ontario, providing cooler northerly flow across Central Indiana. GOES16 shows earlier lake cloud was dissipating. A stream of higher clouds had exited Indiana, leading to mostly sunny skies across the state along with cool north winds. Aloft, water vapor showed deep low pressure aloft over Saskatchewan, and ridging in place over Illinois, Indiana and the Great Lakes. This was resulting in west-southwest flow aloft over the plains streaming toward Indiana.

Tonight through Monday Morning...

Quiet weather along with slightly below normal temperatures will be expected tonight, Sunday and Monday morning. This will be primarily due to the moderate upper ridge found over IL and the Great Lakes. This feature will slowly pass across Indiana tonight and Sunday, before reaching the Appalachians on Monday. Within the lower levels, Indiana will remain caught between surface low pressure over Central Canada and low pressure east of the Carolinas. This will allow influence from a surface high over Quebec to spill southwest toward Indiana tonight and Sunday. Forecast soundings remain dry tonight and Sunday with subsidence in play due to the ridging aloft. Thus mostly clear skies and the continued cool temperatures with easterly flow are expected.

Monday afternoon and Monday Night...

During this period, there will be severe weather potential. Although timing can change between now and then, the best chances appear to be on Monday night. By Monday afternoon, upper ridging will be found east of Indiana, allowing a more progressive southwesterly flow aloft to flow across Indiana A moderate trough axis over the plains will advance toward Central Indiana on Monday afternoon and Night, providing lift. Associated surface low pressure will be moving into the upper midwest on Monday afternoon, placing Indiana within the warm sector. Best areas for convective initiation appear to be over Illinois, with expected propagation east-northeastward through the evening. Forecast soundings suggest a favorable column for convection on Monday Night. Furthermore, a favorable LLJ around 50 knts will be streaming across Indiana, also aiding lift. At this point best confidence for severe weather modes will be straight line wind damage, but as often found in these situations, QLCS tornado spin-ups may also be possible. Monday Night continues to be a weather day to watch.

Tuesday through Saturday...

A cooler pattern with daily chances for showers and storms is expected. Models suggest the upper flow will be dominated by a deep area of low pressure over Ontario. This system will provide a steady cyclonic flow aloft across Indiana and the Great Lakes during this time. Several weak short wave are expected to pinwheel around the low and across Indiana, providing occasional forcing for showers and storms most days. It is too soon for precise timing of these waves. However within the lower levels, a cold front is expected to pass on Tuesday morning, followed by another surface low pushing across Indiana on Wednesday. Forecast soundings each day show favorable lower level lapse rates that could lead toward diurnal convection. This along with the previously mentioned ingredients will require continued daily chances for rain each day.

Regarding temperatures, a cooler than normal temperatures will be expected through the period as northwest to west flow remains predominate due to the deep upper flow aloft.

Smaller chances for a dry day exist on Saturday as the upper low may move east to Quebec by that time, allowing some weaker upper ridging to build across Indiana through the day.

AVIATION (18Z TAF Issuance)

Issued at 134 PM EDT Sat Apr 25 2026

Impacts:

- VFR conditions the rest of today. - Patchy MVFR ceilings late tonight/early Sunday at KLAF, KIND

Discussion:

Partly cloudy conditions are expected this afternoon with scattered to broken clouds in the 030-040 range. Expecting low clouds to clear out some this evening with some high clouds moving in from the MS valley. Later tonight, a reinforcement of low level moisture on easterly winds will bring back in a period of MVFR ceilings from 015- 020 to both KIND and KLAF. These conditions are expected to last until mid-morning Sunday. VFR conditions are then expected at all terminals Sunday afternoon.

Winds from the N-NE from 6-10 kts with a few higher gusts this afternoon gradually shift to easterly by Sunday morning.

IND WATCHES/WARNINGS/ADVISORIES

None.