textproduct: Louisville

KEY MESSAGES

* Warming trend begins today with breezy southwest winds this afternoon and continuing into the overnight hours.

* Widespread showers and possibly some thunderstorms will come late in the weekend and into early next week.

UPDATE

Issued at 945 PM EST Tue Nov 11 2025

Nighttime microphysics satellite imagery shows the last of the mid- level clouds which have persisted across the region today clearing out of the Bluegrass and heading into eastern KY. Mostly clear skies are expected to continue through the overnight hours tonight and into Wednesday morning. While this kind of a setup would typically favor strong radiational cooling, a tight pressure gradient over the region and a seasonally strong LLJ just off the surface should keep moderate, occasionally gusty S/SW winds going through the nighttime hours. While the LLJ is not advecting moisture into the region, there is strong WAA just above the boundary layer, which will keep temperatures much milder across the area tonight. In fact, temperatures remain within a few degrees of the afternoon highs at this time, and any cooling overnight will be very gradual.

For this forecast update, we've nudged overnight temps upward based on latest trends, while suppressing overnight wind gusts slightly as a result of ACARS soundings showing a modest near-sfc inversion, limiting momentum transfer. Sustained winds of 10-15 mph, with occasional gusts of 20-25 mph, should continue overnight, with low temperatures Wednesday morning expected to range from the mid 30s to around 40 degrees.

SHORT TERM /THROUGH WEDNESDAY/

Issued at 241 PM EST Tue Nov 11 2025

Weak troughing and moisture is moving just north of the region today, bringing mid-level clouds and virga. Since there is such a dry layer near the surface, it is preventing precipitation from making it to the surface. It is possible that someone may see a sprinkle or two, but should all remain as virga this afternoon. Additionally, a 45-50kt LLJ is pushing into the region from the west and afternoon mixing is helping to bring gusty winds up to 30mph down to the surface.

These conditions will continue until sunset, where a nocturnal inversion will allow wind gusts to relax. Not expecting the atmosphere to remain mixed overnight, where the LLJ winds could transfer to the surface. Though, the inversion does not look as strong over the Bluegrass, so wind gusts may remain overnight. Clouds will move east of the region during the first half of the night, keeping the rest of the night clear. Low temperatures are expected to be in the low to mid 30s.

On Wednesday, we will begin a warming trend where high temperatures will be in the upper 50s and low 60s. High pressure to the south and quiet northwesterly flow will keep our skies clear and winds breezy up to 20mph.

LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/

Issued at 241 PM EST Tue Nov 11 2025

=====Wednesday Night through Friday Night=====

We will remain under quiet northwesterly flow and surface high pressure through the end of the work week. Temperatures will continue to warm each day into the upper 60s by the weekend. Should be a pleasant week.

On Friday morning, a weak vort lobe and LLJ will move into the region and bring a small chance for some light showers west of I-65. Though trends have decreased over the last several forecast periods, given shallow low-level moisture.

=====Saturday through Early Next Week=====

On Saturday, ridging will move over the Ohio Valley, leading to the warmest day of the week. We are looking at temperatures about 10 degrees above normal in the upper 60s and low 70s. Expecting continued dry conditions for Saturday.

On Sunday, an upper low will shift southeast into the eastern Great Lakes, bringing a surface low pressure with it. A cold front will drag behind the low pressure and begin to stall in the Ohio Valley. Not expecting much for showers and storms along this front, given the drier airmass over the region. But a few showers will be possible.

On Monday, ridging will build over the region, ahead of an incoming trough and surface low pressure system. We should see good moisture return and therefore a chance for showers and storms as the cold front pushes through the region on Tuesday.

====(From Previous Forecast) Extended Forecast Discussion====

Aforementioned upper level wave looks to move through the region on Tuesday with unsettled weather. A broad southwest flow will develop across the southeastern US as a major upper level trough axis drops into the four corners region. A secondary perturbation looks to move across the region on Wednesday bringing another round of showers and possible storms.

High latitude blocking is expected to grow stronger across northern Canada and into Greenland as the NAO becomes quite negative. Aforementioned upper trough axis over the four corners will eject into the Plains by next Thursday and amplify significantly as it approaches the Ohio Valley/Midwest by Friday. Signal analysis has been highlighting the 11/21-22 time frame for the last several weeks. The 11/00Z Euro solution is quite impressive with a negative tilt trough axis and deepening low pressure sliding west of the region. If this evolution should occur, an outbreak of severe weather will be possible from the Ohio Valley southward into the Gulf coast states. We'll need to watch this period of time very closely.

An overall active weather pattern looks to continue into late November. There are increasing signals that the pattern is likely to grow increasingly colder as we move from late November and into December. This is due to several hemispheric conditions that may develop. High latitude blocking is forecast to continue across northern Canada and Greenland. Model teleconnection forecasts show a rather strong -AO/-NAO pattern developing with the EPO likely going negative as well. At the same time, the MJO which is currently in phase 6 is forecast to migrate over into phase 7 as we close out November and head into December. The push into phase 7 is likely being aided by strong stratospheric warming over the Antarctic regions which will shove the MJO into the western Pacific/Western hemisphere. Not to be outdone, there is growing forecast confidence, at least from the Euro model, that we may see some significant stratospheric warming over Canada toward the end of November. To be honest, this is one of the earliest SSW events that I've seen coming out of the models. SSW events usually precede some perturbation of the PV which can unleash colder air masses into the US. The Euro weeklies out through December have been showing the development of a ridge west, trough east pattern for much of December which is in line with historical Decembers that feature La Nina in the Pacific. Bottom line here is that a quick start to winter is becoming increasingly likely and December on a whole may be quite cold for our region.

AVIATION /00Z TAFS THROUGH 06Z THURSDAY/

Issued at 644 PM EST Tue Nov 11 2025

During the upcoming forecast period, winds and wind shear will be the primary driver of new forecast lines as VFR conditions are expected through the current forecast period. As a 50+ kt LLJ moves over the area this evening into tonight, it is expected that a near- sfc inversion will keep most of the stronger winds aloft. However, this inversion is somewhat weak, so forecast confidence is only medium in keeping 20+ kt wind gusts out of the forecast overnight. LLWS is expected from around the beginning of the forecast period through 08-11Z Wednesday, with the stronger winds aloft exiting from west to east tomorrow morning.

Tomorrow, while the pressure gradient will be weakening through the day, gusty winds are likely during the late morning and early afternoon hours. Winds should gradually veer from the SW to the W during the day, with winds relaxing around sunset Wednesday.

LMK WATCHES/WARNINGS/ADVISORIES

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