What happens when the snow melts in the middle of winter? I made a brief video to show you:

Some roads and a few low bridges have flooded, forcing early school closings and rerouting traffic.

A thaw in January is common, but rain doesn’t always accompany it. Sometimes it is brilliantly sunny, inspiring snowball fights in shirt sleeves. A thaw like this is similar to what happens in mud season–except we know winter isn’t over yet. Despite warming up to over 50F today, it will drop below freezing tonight and there’s a chance of snow flurries.

Yesterday, the low here was 8F (-13C). That’s not too surprising. But Dee Nash of Red Dirt Ramblings told me her low that same day was 5F (-15C) in Oklahoma. Whoa! What’s going on here? Check out Eric Berger’s explanation in the Houston Chronicle. It turns out a lot of factors have contributed to the south being colder than the north in many cases.

Of course, today the low was -7F (-22C) this morning, the coldest it’s been all winter. But we’re used to it (whether or not we like it) and those Southerners are not.

Last night it snowed. That, in itself, is not unusual for the second half of October. But normally we get flurries mixed with rain, and no accumulation. Yesterday a weather record for snow accumulation was broken. The official new record is 1.2 inches accumulation. The old record was “trace.” And unofficial reports coming in tell of as much as twice that accumulation.

The view from the porch around 7:30am. (Click to enlarge)

The hillside was past peak color two days ago, but still looked pretty.

Of course, this is all child’s play compared to Buffalo’s October 2006 snowstorm, so I’m trying hard to keep things in perspective. I generally figure there will be one mild day the first week in November to get the final clean up done, and they are predicting temperatures in the sixties next week, so I’m hoping I will still get to plant the box of a hundred crocuses I bought. So I’m trying hard not to panic. But it is disconcerting.

Yikes! Snow predicted for Friday! This is happening too fast for me. Just had first hard frost (26F) last night.

Last night the National Weather Service issued a frost advisory for our area, and we did indeed get a frost. They are issuing a freeze warning for tonight. What’s the difference?

I contacted a member of the local weather station staff. He told me that

Both [the frost advisory and the freeze warning] are only issued during the growing season. A Frost Advisory is issued when the predicted temperature is expected to fall to 36 degrees or lower in the next 3 to 30 hours during the growing season. So temperatures 35 to 40 range would also dictate a frost advisory. A Freeze Warning is issued when there is an 80% or greater chance that the temperatures are expected to fall to 32 degrees (F) or lower in the next 3 to 30 hours during the growing season. If the temperature is expected to fall below 28 degrees (F) this is considered a Hard Freeze.

Radiational Cooling

Another way to look at it is that a frost is caused by radiational cooling, that is, the earth loses enough heat that temperatures drop below the freezing point at ground level. Sometimes when there is a very light frost, the freezing temperature occurs just a bit above ground level. Our first frost this year was a very light one, where the tops of the basil plants got damaged, but the plants themselves survived.

Advective Cooling

A freeze, on the other hand, is caused by advective cooling, where a mass of cold air comes into the area from somewhere else (like the Arctic). This usually signals the end of the growing season for all but the hardiest plants. When the weather service issues a freeze advisory, they are telling you the party’s over. It’s time to get serious about fall clean up and winter preparation.

Time to Get Serious with the Chores

I need to empty and wash the bird bath and bring it in. Oh, and I better make sure the rain gauge is empty. What’s on your must-do list?

I saw frost in shady lawn this a.m., but coleus, cosmos, dahlias all look fine. Just that one spot, I guess.

Today is a gorgeous autumn day. Yes, autumn.

3 inches of rain in last 24hrs. Bet the late blight loved that. Humid & hot today-does it like heat?

Update

Another 1.3 inches of rain fell that afternoon

In the past 4 days have gotten almost 3in rain. Now it’s supposed to warm up. I see weeds in my future. Weeds and blooms.