The latest on the Sunday night frost potential

About the frost chances for Monday morning.......

First of all, NO advisories have been issued for the local area.

NWS Louisville says:  Temperatures will drop into the mid to upper 30s across the area, with low 40s in the typically warmer Louisville metro. There is still the concern for frost potential Monday morning. The coldest spots across the Bluegrass and portions of southern Indiana may see areas of frost while it looks to be more patchy across the rest of the region. Winds and cloud cover across the Bluegrass are still a bit in question however, so ideal radiational cooling may not occur and frost potential would be lower.

NWS Indianapolis says:  HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY SUNDAY NIGHT BRINGING LIGHT WINDS AND MOSTLY CLEAR SKIES TO OUR REGION. THIS MAY ALLOW FOR SOME FROST DEVELOPMENT ACROSS THE AREA...ESPECIALLY LOCATION FARTHER NORTH IN THE CWA. HAVE LEFT IN MENTIONED OF PATCHY TO AREAS OF FROST IN THE FORECAST AND WILL CONTINUE TO HIGHLIGHT THE THREAT IN THE HWO. VERY UNCERTAIN THAT TEMPERATURES AND CONDITIONS WARRANT ANY FREEZE HEADLINES AT THIS TIME...BUT THIS IS CERTAINLY SOMETHING TO KEEP AN EYE ON FOR FUTURE FORECAST UPDATES.

You may need to cover your plants Sunday night. Be sure and check on the latest forecasts.


It is pretty hard to break record lows anymore in Louisville because the weather station is at the airport and there has been so much construction in the last 25 years. This is typical for many cities in the U.S. Urbanization keeps the night time temperatures from getting as cold as they used to decades ago.

The map below shows the average date of the last frost in the spring. For Louisville it is in the last half of April while the countryside is early May.

Average date of latest Spring frost (36 degrees)

At my house just outside the city, I live in a cool valley where morning temps are sometimes as much as 10 degrees colder than the airport. The latest I have ever had frost has been May 5 and I have lived in the same location for over 20 years.
Here is the frost and freeze data for the city of Louisville......
Records:
Latest spring frost (36°):  May 27, 1961
Latest spring freeze (32°):  May 10, 1966
Latest spring hard freeze (28°):  April 23, 1986
Earliest final spring frost (36°):  March 15, 1884
Earliest final spring freeze (32°):  March 5, 1927
Earliest final spring hard freeze (28°):  February 19, 1905
Earliest fall frost (36°):  September 25, 1950
Earliest fall freeze (32°):  October 3, 1974
Earliest fall hard freeze (28°):  October 10, 1964
Latest first fall frost (36°):  November 23, 1902
Latest first fall freeze (32°):  November 28, 1899 and November 28, 2009
Latest first fall hard freeze (28°):  December 13, 1939
Longest growing season:  257 days in 1884
Shortest growing season:  166 days in 1976
Averages:
Average last spring frost (36°):  April 19
Average last spring freeze (32°):  April 6
Average last spring hard freeze (28°):  March 25
Average first fall frost (36°):  October 20
Average first fall freeze (32°):  November 1
Average first fall hard freeze (28°):  November 12



A FREEZE WATCH has been issued for northern Indiana including South Bend and Fort Wayne.

This is a potentially very costly situation for the Great Lakes and northeast for a frost and freeze. Hopefully this will not be the case in the Ohio Valley.


This is the coolest start to spring across the U.S. in a long time and may end up as the coolest.