Advertisement

LJWorld.com weblogs Lawrence Weather Watch

The Fog Blog

Advertisement

Saying that this past week has been a little bit foggy is like saying that we were a little cold in early January. Gross understatements. However, the two are very much related.

I've been asked many times in the last few days why we've been so foggy. Seems that no one has the foggiest idea (shameless pun) as to why we've been stuck with day after day of fog, some lasting all day long. The answer lies in what is currently lying on the ground...our snowpack.

After the Arctic chill in early January, the ground was extremely cold and snow covered. Although the air temperatures have returned to the 30s, not all of the ground temperatures have. That means you've got warmer air right on top of cooler ground. That warmer air keeps melting a little bit more of our snow and that adds more and more moisture to an already saturated air mass.

As that moisture is added to the air situated on top of the snowpack, the dewpoint is increase. Recall that the dewpoint is a very good measure of how much moisture there is in the air. As the air remains situated over a cold layer of snow on the ground, the air itself is cooled down a little bit.

As the air cools down, the temperature becomes closer and closer to the dewpoint. When the two numbers meet, you have widespread condensation since you've reached 100% relative humidity. That leads to fog, heavy frost (like earlier this week when we had freezing fog) and we are left sitting with our heads literally in a cloud.

There is some hope that we'll have fewer fog episodes later in the week as rain should help clear the air of some of the suspended particles that are easily forming into fog droplets each day and also help to melt away more of the snow and let the ground warm back up a touch.

Comments

cj123 4 years, 11 months ago

Thanks for the information! I still find it slighty creepy!

jjt 4 years, 11 months ago

Would all the "blanking "idiots who are driving around at dusk in fog without their "blanking" lights please turn them on?

devobrun 4 years, 11 months ago

"As the air remains situated over a cold layer of snow on the ground, the air itself is cooled down a little bit. "

If it was windy, the fog would blow away or not form. So don't forget the lack of wind as a contributor to the fog.

Stagnant, humid air on top of snow-pack. Fog.

bearded_gnome 4 years, 11 months ago

As that moisture is added to the air situated on top of the snowpack, the dewpoint is increase. Recall that the dewpoint is a very good measure of how

... edit.


Miller pens a blog, in which he bemoans the fog.

Our heads literally in a cloud, living under a perpetual shrowd.

I would not I could not choose the fog.

I would not take it, it is sog.

but here we sit under the fog, feeling like a lost wet dog.

Our weather seers proclaim, clearing coming with a rain.

But we just ponder, are they just stuck in maunder?

I would not I could not choose the fog.

mwmiller 4 years, 11 months ago

devobrun - I almost put that in there, but didnt feel it was applicable this time. There is also advection fog in addition to the more typical radiation fog (the type without the wind). Even though this more humid air advected in a day or two ago with the southeast winds we had, the fog thickened back up Sunday evening, when the winds increased to 5-10mph around the area.

Normally, I'd be right there with you about the lack of wind, but with cloud cover overhead the winds (or lack thereof) aren't the culprit this time. If anything, they are what set up this stagnant pattern to begin with.

Fred Whitehead Jr. 4 years, 11 months ago

GTURN ON YOUR LIGHTS!

TURN ON YOUR LIGHTS!

TURN ON YOUR LIGHTS!

MAYBE YOU ARE A BIG HE MAN OR WOMAN THAT CAN SEE IN TOTAL DARKNESS, BUT OTHERS CANNOT SEE YOU!! GET IT?????

TURN ON YOUR LIGHTS!!

grammaddy 4 years, 11 months ago

Kinda feels like we're stuck in a bad Stephen King movie!

Commenting has been disabled for this item.