Western US Storms, Inverted V variety

 A few weeks back, Arizona was taken over by quite a few "Haboobs". You can go back in my older posts to see some images of this. A Haboob is a major dust/sand storm and in the US deserts areas are most commonly associated with the outflow of thunderstorms.

Older blog posts: http://chicagoirishmatt.blogspot.com/2011/07/photos-haboob-moves-across-south-valley.html or  http://chicagoirishmatt.blogspot.com/2011/07/haboob-part-ii.html  

Today, a few inverted-V profiles (named so because of the temperature/moisture profiles that are plotted from the weather balloon data ... images to follow in this blog post.) were around in Arizona and thunderstorms did result. Click on the next image to see the radar animation.

Click to see this animated gif!

    About pic: The lines of blue moving around are called radar fine lines. In this case, they show the leading edge of thunderstorm outflow moving around. More about this in this next paragraph...

Basically, the situation exists where at the surface and the low levels of the atmosphere, it is very warm or hot and quite dry, thus a very low relative humidity. However, moisture in the mid levels of the atmosphere over the area allow for storms to form. What happens? You get storms to form and produce rain. The rain sinks into air that becomes drier and drier (increasingly lower relative humidity as rain gets closer to the ground.) Most of the rain evaporates in the very dry air. When water evaporates, the air cools. (See subjects like Latent Heat, Specific Heat, etc, for an understanding of this process.). The colder the air, the more dense it is. Dense air sinks as it is surrounded by less dense air. This cool, dense, air sinks to the ground and spreads out. This process is simply named "thunderstorm outflow". In the case of the Inverted-V, you get very strong evaporation and thus can get very strong outflows. And because it is so dry and so little rain hits the ground, this can be a huge fire hazard! Why? Imagine lightning strikes with little rain and lots of wind? Bad bad news!

About the Haboob situation. When you have these strong storms, and "dry" storms at that, over an arid/desert type ground, guess what happens? Lots of wind over a surface with lots of dust and sand means walls of sand/dust moving along. A Haboob is born! :)  (Again, see more in my blog or just check out Google for images/info on Haboob storms.)

So, lets see a few soundings (weather balloon data.) First, what is called a STUVE. It is more easily understood by the non meteorological minded viewer. And I put a few labels on there to show you what is going on. The next 2 will be the more common Skew-T profiles for both the mets that might care about this blog as well as show you why it is called an inverted-V. Notice the upside-down V profile at the lower part of the sounding. The Tuscon Skew-T really shows the Inverted-V profile well.

Couple of notes for non-mets. When red and green lines are close, that means the RH is high. When they are far apart, it is dry -- the RH is quite low. The lines might be confusing but just know this is a plot of temperature w/ height and moisture w/ height.

Stuve type sounding for Flagstaff

Skew-T for Flagstaff

Skew-T for Tuscon

Thank you College of Dupage/NexLab http://weather.cod.edu for much of this weather data. Also thank you GrLevelX.com for the radar images.

Been a hot one in Chicago..

What a week in Chicago with the heat! Today ended 7 straight days (at Midway Airport, on the south side) of 90+ with 2 days over 100, and heat indexes around 110. Some southern suburban locations got near 115 with the heat index and the streak of 90's continues. Today is the cool day of the bunch but heat indexes are still well into the mid 90's. The only reason today wasn't that bad is we had our largest calendar day precipitation event in recorded history...almost 7" of rain at O'hare airport. 7 days of heat followed with a day of flooding! Phew!

Working at Midway the day of the 101 F high, I took a picture of the ASOS's temperature sensor 1-minute update. This wasn't when the 101 was recorded, but I just loved all the 100's and 1 minute hits at 101 (you would need a 5 min avg of 101 for it to be official, which it was later on.)

This is nothing compared to the heat that has gone on in much of the country the past few weeks, and the east coast the last few days, but hot none-the-less.

Heavy rainstorms are Chicago's latest weather nightmare - chicagotribune.com

Heavy rainstorms are Chicago's latest weather nightmare - chicagotribune.com

Even northern Maine gets supercells and tornadoes :)

A zoomed-out view of the storm to show the location in the far northern parts of Maine.

Zooming into the base-reflectivity

Zoomed in Storm-Relative Velocity. There was about 85 kts of shear in this at the time.

Amarillo is baking in this heat! 100 degrees, anyone?

060   
NOUS44 KAMA 151329  
PNSAMA  
OKZ001>003-TXZ001>020-152300-  
  
PUBLIC INFORMATION STATEMENT  
NATIONAL WEATHER SERVICE AMARILLO TX  
828 AM CDT FRI JUL 15 2011  
  
YESTERDAY...JULY 14...AMARILLO...BORGER...DALHART AND GUYMON REACHED  
100 DEGREES OR MORE. THIS BRINGS THE NUMBER OF 100 DEGREE DAYS IN  
AMARILLO IS UP TO 22. THIS IS 4 DAYS SHY OF THE RECORD OF 26 DAYS IN  
1953. IN ADDITION...AMARILLO TIED A DAILY RECORD HIGH MINIMUM OF 74  
DEGREES THAT WAS LAST SET IN 1940. 

And today, July 15th, it hit 100 again. So that makes 23.  

Thanks to NEXLAB (http://weather.cod.edu/) for the text info, 

via the Amarillo NWS. Also thanks to The Weather Channel for 

tweeting out the info to clue me in, to look for it. :) 

Summer Surprise in Nebraska

Interesting to see tornado watches in CO and NE today. Well, maybe not so much in CO but through NE. It is far  from a synoptically evident area this time of year, normally, and today's morning analysis (from what I went back and looked at) showed nothing to depart from this norm.


First, I see the watch ....

So then I take a look at radar and see the storm ..

and am immediately impressed. It had about 90 kts of shear (delta-v) at the time of this image (I didn't save the velocity image..just trust me.) and a report, via Fire Dept and Rescue, of a tornado 15 minutes prior to this.

So naturally I wanted to look at what the total shear looked like and the VWP (VAD Wind Profile -- you can look that up if you don't know what that is :) ) to see what the profile looks like. Very impressive low levels, while the mid/upr levels are average, at best. But this is an isolated cell in a fairly capped envioronment so it had plenty of time to spin. No contamination, no cell interactions, etc. 

I figured I would look at the surface data. Is there a front? I haven't looked at anything all day so I have no idea what's going on!

Click to enlarge!

It isn't super obvious to the naked eye what the boundaries are, but you can see a nice moisture axis from KS into the NE PH with nice backed winds along southern Nebraska.  This would certainly be a case to prove that one needs to break out the colored pencils and dive into the data and analyze it to death. Again, this isn't synoptically evident! This requires some real meteorological analysis ...and no model would help you here, for sure!






So, what are some of SPC's mesoanalysis magic numbers saying? First, the SRH ...

 Certainly a lot of Shear in the low levels! You could see that from the VWP profile from above -- and this storm was very close to that radar, but nice to see the analysis in this image match that thought.

What about CAPE/CIN?

Clearly, a lot of CIN around but this is after 9pm. I'm sure, earlier, it was a little less capped and I would think the fact there are storms in the area proves that. If it doesn't, then, well, I give up. But it does show a max cape area, in an area of high low level shear. Not bad! When you have isolated storms that aren't going to encounter a ton of outflow/contamination/mergers, etc, they can survive as supercells even if the total shear isn't all that grand. What they need is time and an isolated storm has nothing but time.



I certainly didn't do a long, detailed, analysis of what was going on today/tonight -- and maybe this tornado was bogus -- but it certainly goes to show you the atmosphere likes to surprise us! 

Chasing this, though, would be impossible. No one in their right mind would have driven to that location today to see this unless you lived within a couple of hours or so and really were on top of things.

Very cool stuff today!

Lake Superior is really cold!

I do NOT plan on swimming in Lake Superior, anytime soon. The following image is provided by CIMMS/UW. Thanks to them for this image! Click image to get a full sized image.

http://cimss.ssec.wisc.edu/goes/blog/archives/430

Haboob Part II

I'm not sure when this was, but this gif was created by the National Weather Service in Lubbock, TX, from an event they obviously had in their county warning area. It explains how a haboob can form very well. In AZ, the monsoon season kicks in. You get thunderstorms around, cool rain falls..producing cool/dense outflow. The air spreads out, and if the downdraft is strong enough, results in rather high winds. Those high winds pick up sand/dust and create the haboob event (a strong sandstorm.)

edit: found the event on the Lubbock, TX NWS page:
http://www.srh.noaa.gov/lub/?n=events-2006-20060622_haboob

Click for a larger image

PHOTOS: Haboob moves across south Valley

PHOTOS: Haboob moves across south Valley

Dust/Sand storms are plowing into Arizona right now as Monsoon season kicks in. I don't know if this link/picture is time sensitive or not but hopefully you'll see it soon. If not, just do a google search for Haboob and enjoy :)

Pretty bad forecasting

I continue to realize more and more just how hard it is for "regular people" to think highly of meteorologists. I forecast less and less now and thus rely on the forecasting of those who are paid to do so. Generally, I check the Chicago National Weather Service's zones or point forecast for my area.

This weekend was brutally bad ..
Friday July 1st: Forecast of mid to upper 90's with Heat Index Values of 105-110. Thunderstorms formed along the lake keeping the city and most of the metro area in the 70's much of the day with a cool breeze. It finally warmed up towards late afternoon for a high of 89. But, the dewpoints never got that high (in the mid 60's instead of the low 70's) and the heat index was far from bad. A heat warning had been issued the night before but obviously, did not verify.

Saturday July 2nd: No heat warning today. High of "near 90". Result? It was 94 at Midway with a heat index above 100. Kankakee had a heat index of 110! Almost everyone was into the low 90's with heat indexes at or around 100. Painfully hot. Given the bust the day before, the heat on this day was magnified. Heat warning day, cool..non heat warning day, brutally hot.

Sunday was fine ...

Monday July 4th: High in the low 80's, mid 70's near the lake. It was 89 at O'Hare (same as Friday!!) and 90 in many suburban locations. Waukegan, a northern suburb right on the lake, got up to 82! So it was as hot on this day for most people as it was on the heat warning day. Big difference between low 80's and around 90!

Not a good weekend. I heard numerous complains at various places I was at and since I was relying on the same forecasts, I felt their pain.

Do I know how hard it is? Did I used to mess up? Of course. But I get it! I get why people say 'weatherman are always wrong". This weekend was a big weekend for outdoor plans and for the weather service to be this bad? Lets just say it .. "EPIC FAIL". With a Cubs-Sox series, the Taste, Ribfest in Naperville, and the 4th of July all going on, anyone that made plans revolving around a forecast would have been screwed. Luckily, most people have just resigned to this motto.
"It is the weather, you can't control it so just go with it". Simply put, they ignore the forecast and just hope.

I made the mistake of trusting the forecast because I was a part of it so long. Turns out, ignorance IS bliss.

Hudson Bay, Ice

It may be July but Hudson Bay still has plenty of ice! The animated gif below and far more about this can be found at the  CIMMS Satellite Blog