textproduct: Louisville

KEY MESSAGES

* Isolated showers and storms are possible across southern KY through late this evening.

* Warm and breezy conditions are expected Sunday, with highs in the 80s across the area.

* Strong to severe storms are possible Sunday evening into Sunday night, with a Slight Risk (Level 2/5) issued along and north of I- 64. Hail and gusty winds are the primary severe hazards.

* Cooler and mainly dry conditions are expected early next week. Milder temperatures and rain chances return by Thursday.

SHORT TERM /THROUGH TONIGHT/

Issued at 403 PM EDT Sat Mar 21 2026

This Afternoon through Tonight...

At this hour, a narrow band of showers extends from central into southeast KY. This area of showers, which briefly produced a few lightning strikes as it moved across portions of central KY over the past 2-3 hours, has developed right along a remnant cold frontal zone. Dewpoints are in the upper 40s and low 50s to the northeast of this boundary, with dewpoints in the upper 50s and low 60s to the southwest. Model soundings indicate that these showers were able to develop in a pocket of instability between 10-20k ft AGL, with convective towers struggling above this level. Mid-level temperatures are beginning to increase from the west, which should help to limit additional development later this afternoon. With this being said, greater moisture and lingering cooler temperatures aloft may be sufficient for isolated convection across southern KY this evening, particularly around Lake Cumberland. We'll keep an isolated shower/storm chance in the forecast through around 03Z, with dry conditions expected elsewhere this evening. After midnight, all locations in the CWA should be dry as upper-level temperatures continue to warm and stability increases.

A broad area of low pressure is expected to develop from the central Plains up into the Great Lakes tonight as a H5 jet max moves across the northern US. As this area of low pressure gradually approaches the Ohio Valley, winds will gradually increase out of the S/SW overnight, with speeds still remaining at/below 10 mph in most areas. This southerly flow will spread the higher dewpoints back across the entire area, limiting the amount of cooling overnight. In spite of mostly clear skies, lows Sunday morning should only fall into the upper 50s and low 60s across the area.

Sunday and Sunday Night...

With height/pressure falls expected to the NW of the region tomorrow, a strengthening pressure gradient should bring a return of breezy SW winds across southern IN and central KY. At least intermittent sunshine should allow for good mixing during the day, bringing stronger winds and gusts down to the surface. From late morning through the mid-afternoon hours, sustained winds of 10-20 mph with gusts of 20-30 mph are expected across the area. This flow regime will also support strong WAA, with high temperatures rising into the 80s Sunday afternoon.

The main period of impactful weather is expected Sunday evening into Sunday night as a cold front begins to drop from north to south across the region. While model soundings show a capped thermodynamic profile through much of the afternoon tomorrow, as the front moves toward southern IN and northern KY in the evening hours, some weakening in the warm layer aloft is expected. When combined with lift from the convergence along the front, hi-res guidance suggests that forcing should be sufficient for showers and storms to develop.

The potential for strong to severe storms remains relatively unchanged for Sunday evening into Sunday night, with SPC maintaining a Slight Risk (Level 2/5) for areas along and north of the I-64 corridor. While the probabilities of damaging winds and hail are almost identical in the SPC outlook, would tend to see hail as being the primary threat across our area, with damaging winds as a secondary (but still noteworthy) risk. Model soundings show steep mid-level lapse rates within an EML, with 7.5-8 deg C/km mid-level lapse rates and 1000-1500 J/kg CAPE supporting robust updrafts, especially within the Slight Risk area. While low-level lapse rates will be steep with high DCAPEs tomorrow afternoon, there is a consistent signal in hi-res guidance in convection firing slightly behind the front, resulting in elevated convective initiation and a much more stable low-level thermal profile. If convection can fire closer to/ahead of the front, then some stronger cores may be able to bring gusty winds down to the surface. Out of all the severe hazard type, the tornado threat looks to be really low, and it will be zero if convection is elevated as depicted in hi-res guidance.

Residence time of showers and thunderstorms should be fairly short, and precipitation amounts are not expected to cause significant flooding concerns at this time. The main time for strong to severe storms is still in the late evening and early overnight hours Sunday night, or between 8 PM and 3 AM EDT. Behind the front, northerly winds will cause temperatures to drop quickly, falling into the 40s and low 50s by Monday morning.

LONG TERM /SUNDAY THROUGH SATURDAY/

Issued at 403 PM EDT Sat Mar 21 2026

Monday - Tuesday Night...

The cold front which will bring the chance for showers and storms Sunday evening into Sunday night is expected to quickly drop to the south and east of the area, with clearing conditions expected by Monday morning. In the wake of the front, 1034 mb sfc high pressure is progged to drop into the lower Great Lakes and Midwest on Monday, bringing a drier and cooler air mass into the region. NW flow in the mid-to-upper troposphere should continue into the day on Tuesday over the Ohio Valley, with upper ridging over the western CONUS flattening out a bit. This should help to nudge the sfc high to the east toward the mid-Atlantic by Tuesday afternoon, as the low-level flow transitions from CAA/northerly on Monday to light easterly. Expect temperatures to moderate as a result, with temperatures on Tuesday being near climatological norms for late March. Scattered mid- and high-level clouds are expected through the period.

Wednesday - Friday...

Through the middle portion of the upcoming week, the synoptic pattern over North America is expected to become more zonal as upper level energy attempts to lift up and over western US ridging. Initial mid-level disturbances within the broader NW flow pattern are expected to approach the region Wednesday evening into the first half of the day on Thursday. There has been a fairly consistent signal in this wave bringing a chance of rain somewhere over the lower-to-middle Ohio Valley during this time period; however, exact timing and specific locations are variable among the different ensembles. As a result, forecast confidence is only medium in these precipitation chances, with higher confidence in a continued warming trend next Wednesday into Thursday.

A stronger/higher confidence signal for rain and storm chances arrives later on Thursday into Friday as a second shortwave rides across the northern US. This disturbance is expected to bring a cold front into the Ohio Valley, with temperatures and moisture surging ahead of the front on Thursday. Thursday should be the warmest day of the upcoming week, with highs currently expected to return to the upper 70s and low 80s. With moisture expected to increase along the front and faster deep-layer flow expected in the vicinity of the upper shortwave, the ingredients appear reasonably favorable for organized convection with this system. Although it's still a ways out, and ensemble spread is considerable, we are seeing a weak- moderate signal for severe storms in the AI/ML guidance for the Thursday night-Friday period, so we'll have to keep an eye on this over coming days.

By the end of the week, medium-range guidance begins to diverge in its handling of the upper shortwave and sfc cold front. Some guidance amplifies the shortwave into a deeper east coast trough, allowing cooler and drier air into the area Friday into Saturday. Other guidance keeps the front over the region for a longer period of time, which would keep a chance for rain lingering Friday, and possibly into the first part of next weekend. As a result, forecast confidence in specifics is low at this time beyond Thursday night.

AVIATION /00Z TAFS THROUGH 06Z MONDAY/

Issued at 742 PM EDT Sat Mar 21 2026

VFR conditions are expected to remain through at least the next 24 hours as winds remain out of the south to southwest. Light winds tonight will increase and become gusty around midday tomorrow. Gusts to near 25 knots are expected. Towards the end of SDF's extended period, a west to east oriented cold front dropping south will bring some convection towards the airfield. This could drop ceilings to IFR levels for 2-3 hours near 6z Monday.

LMK WATCHES/WARNINGS/ADVISORIES

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