Cold front on IR

[Jeff Duda]

Ever wonder what a cold front looks like on infrared satellite? Many of them are too weak to be seen, but the stronger ones in the cold season occasionally show up on IR imagery. It's pretty cool when they do. I was able to capture the cold front from the big system that is traversing the country this week as it blew through Texas and Oklahoma.

The two links are animated GIFs for the same loops, but one of them has higher temporal resolution than the other, but also lower spatial resolution (in terms of the images).

Higher temporal resolution, lower spatial resolution (5.28 MB)

Better resolution, but lower temporal resolution

 

[Connor McCrorey]

What I love is the lakes clearly showing up as warm spots across TX, E OK, and AR. Thanks for putting this together!

 

[MClarkson]

Thats pretty cool looking.

 

[Jeff Duda]

Dewpoint animation

I spend a lot of time analyzing data from WRF simulations that I'm doing for my masters thesis. I made this animation today when I noticed many significant meteorological events occurring in it. The animation in the link is a 24-hour animation of surface dewpoint in 15-minute intervals. The model run uses the WRF-ARW with 3km horizontal grid spacing. It is initialized using NAM Analysis data starting at 12Z on 22 May 2007.

Dewpoint animation (6.93 MB)

Things to note:
-solid southerly moist flow in the eastern half of the domain throughout most of the simulation
-the dryness over NM, SE CO, SW KS, and the TX/OK PHs that oozes eastward throughout the simulation. This is the traditional SGP dryline and the gradient becomes quite tight in the late afternoon (2000 UTC) as would be expected. Note also the dryline bulge that forms in W KS. Thunderstorms do indeed form north/east of this bulge, as you can see by puffs of drying just in front of the gradient.
-the extreme dryness in S WY that flows E/SE through CO, NE, and KS throughout the simulation. This is a cold front. Notice how the dewpoint gradient along it is not as tight as it is along the dryline.
-in far SE CO and SW KS, notice how some areas start relatively moist, then dry as the dryline passes, then remoistens as the cold front approaches, then finally redries in its wake. That would be some hell of a roller coaster ride in dewpoints in places like Dodge City.

You can also see the diurnal cycle of heating as the plot generally becomes messier with rougher gradients and contours during the day, then smoothing at night. This shows the flux of latent and sensible heat at the surface during the day being forced by solar radiation.