Frost and Freeze Threat Continues

I consider September a "lagging month".  Yes, fall officially arrives around the 21st of the month each year, but summer's heat can hang on stubbornly, and not simply in the South.

This year, this heat lagged into the first few days of October.  Then came a dramatic reality-check.  

An upper-level wind pattern tapping Arctic air is shoving a cold front south into the U.S.  Check out these amazing changes:

- Billings, Mont. went from a high of 82° Tuesday to just over 2" of snow the following day, their first snow of the season.

- According to the National Weather Service in Boulder, Colo., the town of Sedgwick, Colo. had a daytime high of 90° Wednesday followed by a freeze the following morning.  Talk about wardrobe confusion!

- Grand Forks picked up its first snow of the season (2-3") Thursday, just two days after a high of 80°. 

- Similarly, Denver registered two straight days with highs in the low 80s Tuesday and Wednesday.  Then, a light, slushy coating of snow fell before sunrise Friday morning.

(PHOTOS:  An Early Taste of Winter)

Considering this is only the first weekend of October, the magnitude and scope of the cold air is quite impressive.  Let's hit the chilly details.

Frost/Freeze Potential

Freezing or near-freezing temperatures, the first of the season for some, occurred Sunday morning as far south as eastern New Mexico, the Texas Panhandle, northern Oklahoma, Kansas, and southern Missouri.

Selected record-low temperatures tied or broken Sunday morning included:

• Sioux City, Iowa:  15° (old record 23º in 2000; coldest on record so early in season)
• Mason City, Iowa:  19° (old record 20° in 1896)
• Scottsbluff, Nebr.:  21° (tied record from 1952)
• Waterloo, Iowa:  24° (tied record from 1988)
• Ottumwa, Iowa: 25° (old record 26° in 2000)
• Grand Junction, Colo.: 30° (old record 31° in 2007)
• Tulsa, Okla.: 32° (old record 33° in 1952; also earliest autumn freeze on record)

Grab a jacket for the bus stop Monday morning in the Southern Plains, Ohio Valley, and Great Lakes.  A frost or freeze is possible in those areas. And of course, if you have tender plants or vegetation outdoors, you'll want to either cover them or bring them indoors.

(LOWS MAPS:  Monday)

"Highs" in Name Only

Behind the cold front, high temperatures won't be all that, well, high this weekend in the Midwest, Rockies and increasingly in the South.

We'll see some recovery in the Plains Sunday, with 50s and 60s for highs replacing some of the stubborn 30s and 40s in the High Plains and northern Plains.  

However, by local standards, it will still be a chilly day in parts of the southern Plains, including another day in the 50s in Dallas.  More clammy 50s will be the best we can do Sunday in St. Louis and Chicago.

The cold front will also sweep into the East.  Its attendant clouds and precipitation will hold high temperatures in the 50s or even upper 40s in the Northeast Sunday.