textproduct: Louisville

KEY MESSAGES

* Hot and humid conditions will continue through the end of the week and into the holiday weekend. Afternoon temps will climb into the lower 90s with heat indices in the 105-110 range. Extreme Heat Warning will continue through Friday. A Heat Advisory will be in effect late Friday night through Saturday evening.

* There is a risk of afternoon/evening storms this afternoon through the weekend and into next week. A few strong storms with gusty winds, heavy rainfall, and intense lightning will be possible.

* Unsettled, muggy weather continues through early-to-mid next week with modest relief from hot temperatures likely.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 245 PM EDT Thu Jul 2 2026

Afternoon satellite imagery clearly shows our upper high centered over west-central KY. Another decent Cu field has developed and temperatures are in the lower 90s across the region with dewpoints in the mid-upper 70s. This combination of T/Td is yielding heat index values around 100 in the Bluegrass and in the 105-107 degree range in areas west of I-65. For the remainder of the afternoon, not expecting much convective coverage across the region. This is due to a capping inversion which will likely keep convection at a minimum. The best chance of convection looks to be on the southwest/western side of the upper ridge where satellite imagery shows an agitated Cu field in swing from middle TN into western KY. MLCIN in this region is much weaker and with low-mid level lapse rates around 7.5 C/km, and PWATs up around 1.75 inches, there is a risk of strong/severe storms that fire. Main weather hazard would be wet microbursts with damaging wind potential. Our current thinking is the best chances of storms this afternoon/evening would be west of a line from roughly Bowling Green to Owensboro. Elsewhere, we expect afternoon temps to top out in the lower 90s with heat index readings in the 100-110 range.

For this evening, with the loss of heating, any convection that fires looks to quickly diminish after sunset as the boundary layer stabilized. Another muggy night is expected with temperatures falling into the lower 80s this evening before settling down into the mid-upper 70s during the overnight. Patchy fog development will be possible across southern KY, especially in the river valley locations.

Moving into Friday, very warm and humid conditions are expected to continue across the region as upper level ridging will still hold reign across the region, though with a decreasing influence. With the ridge moving off to the east, we expect to see a bit less capping in the afternoon which would allow a higher chance of convection across the region in the late afternoon/evening. Model soundings continue to show plenty of buoyancy across the region. However, synoptic scale forcing will remain rather nebulous. So we'll likely have to rely on left over mesoscale boundaries and differential heating for convective initiation. At this time, we'll continue to run chance PoPs in the afternoon across the central and western areas. Across the Bluegrass region, residual capping with the departing ridge will likely keep convection at a relative min in this area. Flow aloft will be weak, so storms that go up will not move too much until they become outflow dominant. Given ample instability tomorrow afternoon, wet microbursts with gusty winds will be the primary threat. Heavy rainfall and lightning will be possible. Widespread flooding is not expected. However, RFC guidance suggests that we can handle about 1.75-2 inch/hr rates before flooding may commence. Thus, isolated hydro issues could crop up where slow moving storms could fire. Convection will likely diminish rather quickly after sunset with lows dipping back into the mid-upper 70s toward dawn Saturday.

After coordinating with surrounding offices, we will continue the Extreme Heat Warning through Friday evening as we'll have another day of heat and offensive humidity. The recent rainfall has led to a saturated soil across the region. Despite nearly 4 days of nearly full sun, we have not dried out and most of the radiation coming in has gone to dry the soil and not heating the air. Additionally, our vegetative cover is lush and green which is helping drive evapotranspiration producing this high humidity. Given that we've underachieved the last couple of days, have opted to let the Extreme Heat Warning go until expiration Friday night, but it will revert to a plain Heat Advisory for Friday Night and into Saturday. This was done to keep the public's attention on heat as there are a number of outdoor celebrations this weekend and potential for additional heat related stress on folks out and about.

..Saturday through Wednesday

The dominant upper-level ridge over the Eastern US begins to weaken and shift slightly eastward. Surface high pressure continues to pump ample moisture and fuel into the region. While instability remains relatively high with SBCAPE values ranging from 3500-4000 J/kg, there isn't much force behind this surge in moisture. Rounds of summertime-like pulse convection are likely to develop throughout Saturday and Sunday, but a complete washout is not expected. PWAT values continue to remain high (1.75-2.0") so isolated shower or storm that does develop have plenty of moisture to work with. Along with potential isolated heavy downpours from these convective showers and storms, the SPC has included much of the region in a Marginal (1/5) risk for severe weather on Saturday, as the increased instability could support isolated wet microbursts within these storms.

A Heat Advisory was issued for Friday 9 PM EDT/8 PM CDT to Saturday 9 PM EDT/ 8 PM CDT as hot and humid conditions remain for much of the weekend. High temperatures remain in the low to mid 90s and dewpoints in the mid-70s, making for another sizzling day. However, depending on the coverage of isolated convection, some areas could remain cooler with temperatures in the upper 80s.

By Sunday afternoon, upper-level ridging is expected to build over the Northern Great Plains, and an upper-level shortwave is expected to swing a cold front across the region. A better forcing mechanism along this front and diurnal heating supports the development of scattered showers. The front is expected to slowly sag southward, keeping much of the region locked under ample moisture and instability (roughly 2500-3000 J/kg SBCAPE).

By Monday and Tuesday, some deterministic models favor the front stalling to the south, keeping the northern CWA drier on Tuesday as surface high pressure builds behind. However, others keep the front locked over the region, continuing to allow showers and storms to develop for much of the CWA. Nevertheless, afternoon and evening rain chances look to remain in the forecast throughout the first half of the week with 35-50% PoPs across the region. Hot and humid conditions are still expected for through the next work week, but slightly lower temperatures follow behind the front with afternoon highs in the upper 80s to low 90s across the CWA.

AVIATION /18Z TAFS THROUGH 00Z SATURDAY/

Issued at 118 PM EDT Thu Jul 2 2026

VFR conditions are expected to remain for most of the region throughout the forecast period. Isolated showers and storms are expected to develop along the KY/TN border this afternoon, resulting in a PROB30 for BWG from 20Z to 23Z. These showers and storms are expected to dissipate heading into the evening, with BWG returning to light and variable winds. Elsewhere, light and variable winds are also expected for much of the period before calming throughout the night.

LMK WATCHES/WARNINGS/ADVISORIES

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