Midwest heat wave generates a heat index of 131° in Iowa; Bret no threat

By: Dr. Jeff Masters , 1:18 PM GMT on July 19, 2011

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A unusually intense, long-lasting, and widespread heat wave with high humidities continues to plague the Central U.S. The heat index--how hot the air feels when factoring in both the temperature and the humidity--exceeded 100°F in twelve states on Monday and thirteen on Sunday, with the dangerous heat extending from Texas northwards to North Dakota, Minnesota, and Wisconsin. At least thirteen deaths are being blamed on the heat in the Midwest. The heat index hit a remarkable 131°F at Knoxville, Iowa on Monday, and a heat index in excess of 120° was recorded at numerous locations in Iowa, Minnesota, and Illinois.


Figure 1. Predicted maximum heat index for Thursday, July 21, 2011. Portions of 33 states are predicted to have a heat index in excess of 100°F. Image credit: NOAA.

A 1-in-7-year heat wave coming for the Eastern U.S.
The extreme heat will shift slowly eastwards this week, peaking in Chicago on Wednesday, Detroit and Pittsburgh on Thursday, and New York City and the mid-Atlantic states on Friday. Temperatures near 100°F are expected in Detroit on Thursday and New York City on Friday. Detroit has hit 100°F 18 different years in its 137-year record, and New York City 22 years out of the past 140 years, so this heat wave is expected to be about a 1 in 7 year event. While that makes it a notable heat wave, the most remarkable feature of this July 2011 U.S. heat wave is the humidity that has accompanied the heat. A heat index over 130°F, such as was observed yesterday in Iowa, is very rare in the U.S., and extremely dangerous. According to Christopher C. Burt, wunderground's weather historian, the only place in the world where a heat index over 130°F is common is along the shores of the Red Sea in the Middle East. A major reason for the remarkably high humidities accompanying the July 2011 Midwest heat wave is the record flooding the region experienced over the past three months. As pointed out by wunderground's climate change blogger Dr. Ricky Rood in his latest post, with hundreds of thousands of acres of farmland still inundated by flood waters, and soils saturated over much of the Upper Midwest, there has been plenty of water available to evaporate into the air and cause remarkably high humdities. This makes for a very dangerous situation, as the human body is not able to cool itself as efficiently when the humidity is high. The extreme heat will last through Sunday in the mid-Atlantic, but should end on Monday, when a cold front is expected to sweep across the region. However, the latest models suggest the heat will re-amplify over the Midwest next week.


Figure 2. Tropical Storm Bret at peak intensity, at 5:15 pm EDT on Monday, July 18, 2011. At the time, Bret was building an eyewall and had begun to clear out an eye. Image credit: NASA/GSFC.

Tropical Storm Bret weakens
Tropical Storm Bret enjoyed a brief burst of intensification yesterday afternoon that brought the storm's winds up to 65 mph. However, Bret has sucked in a lot of dry air today, and is now a much weaker storm with winds of just 50 mph. Satellite imagery shows that Bret has not improved in organization this morning, thanks to dry air to the northwest that has been blown into the storm's core by upper-level northwesterly winds. Wind shear is a high 20 - 25 knots, and is expected to remain in the high range for the next three days. The combination of high wind shear and dry air nearby should act to keep Bret from strengthening, and the storm should slowly decay as it heads out to sea over the next few days. Bret is not a threat to any land areas.

None of the reliable models predict tropical cyclone development over the remainder of the Atlantic through July 26.

Weakened Typhoon Ma-on nearing Japan
Typhoon Ma-on has weakened to minimal Category 1 typhoon with 75 mph winds, and is battering a large swath of the south coast of Japan with tropical storm-force winds, as the storm slides northeast along the coast. Ma-on is expected to turn eastwards out to sea by Wednesday, and is not likely to bring tropical storm-force winds to the troubled Fukushima Nuclear Plant.

Jeff Masters

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African disturbance showing up a the 'small' probability tab...at the moment.
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Quoting CaneHunter031472:
I couldn't see the GFS forming anything on this link is there any better link to the models? can someone share them with me pls?

Link


I can't get that site to work anymore. Found this link to it. May help. :)
Link
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Quoting CaneHunter031472:
I couldn't see the GFS forming anything on this link is there any better link to the models? can someone share them with me pls?

Link



You can try this one. If there's something better I'd like to know also.

Link
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I think its safe to say that the wave in the Central Atlantic is gathering steam, moisture, etc...
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I couldn't see the GFS forming anything on this link is there any better link to the models? can someone share them with me pls?

Link
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.
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BTW, Bubble Guppies comes on Nick right before Dora. If they could name a Hurricane Bubble Guppies my daughter would freak out!
Member Since: May 26, 2011 Posts: 0 Comments: 1193
Quoting TropicalAnalystwx13:


Timing is everything, and you may be right about this season setting up like last year's, but I find it unlikely the USA will go unscathed this season.
It would be a miracle..jmo
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Quoting CybrTeddy:
If the ECMWF is right, Cindy would develop off North Carolina from a trough similar to Bret - but stronger in intensity. We'll see what happens.


Huh? I think the ECMWF shows that storm developing from the wave in CATL
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Hey Flood!! How's it going Bro?

It looks like a few good waves moving around out there today.

D.
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The models are all dancing around the possibility the wave off Africa will continue westward and attempt to develop as soon as perhaps Monday. The ECMWF is starting to show in the long range another trough split off the East Coast, though remember this is the first run showing this and the ECMWF can spin up ghost storms. I do think though it is possible we'll see another named storm next week.
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Quoting Floodman:


Yep, we just had a good one blow through here (NW San Antonio) a little while ago
Hello Floodman...Interesting loop Ted posted...Link
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Quoting CybrTeddy:
The ECMWF just posted isn't updated - this one is, Storm off North Carolina and stronger from the 00z. If the ECMWF is right, we could be staring at an invest as soon as Saturday.
Link
Wow...Has it over Miami..Thank you for da link..:)
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If the ECMWF is right, Cindy would develop off North Carolina from a trough similar to Bret - but stronger in intensity. We'll see what happens.
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Quoting hydrus:
The 240 hour frame has a storm on or near the Cape Canaveral...

Look at the surface isobars.. thats not a storm, thats a spot of high vort.
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Quoting Floodman:
Good afternoon, by the way, everyone...


Good afternoon. And I'm glad you got a giggle. That always makes your day a little bit brighter. Gotta love the blog. :)
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Quoting SLU:


That's the same wave at 35W!
I thought you noticed that already..It reminded me of 1985,s Gloria, just closer to Florida...And in July instead of September...
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Does not make any sense. Recon is finding pressures near 1000 mb, with winds between 55-65 mph. Yet, the satellite below has the appearance of a weak tropical storm/tropical depression.

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The ECMWF just posted isn't updated - this one is, Storm off North Carolina.
Link
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Member Since: July 15, 2006 Posts: 192 Comments: 59571
Quoting AllStar17:
Bret down to 1000 mb this vortex pass. Was at 1002 mb last vortex.


According to recion, Bret is strengthening. According to satellite, Bret is weakening. It will be interesting to see what the National Hurricane Center does with this.
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Quoting bohonkweatherman:
There is good Texas weather news, Pretty good scattered storms developing in South Central Texas due to high heat and area of rain around Houston has maintained itself, so a little relief.


Yep, we just had a good one blow through here (NW San Antonio) a little while ago
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Q: When will Cindy develop in the Atlantic?

A. This week
B. Next week
C. First week of August
D. Second week of August

Q: Will we see another named storm in July?

A. Yes
B. Maybe/Probably
C. Yes

Q: How many named storms will we see in August?

A. None
B. 1
C. 2
D. 3
E. 4 or more
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359. SLU
Quoting hydrus:
The 240 hour frame has a storm on or near the Cape Canaveral...


That's the same wave at 35W!
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Bret down to 1000 mb this vortex pass. Was at 1002 mb last vortex.
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Good afternoon, by the way, everyone...
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356. SLU
Quoting stoormfury:
SLU you are so correct. have more faith in the euro model than the rest. the euro model was the only one that nailed Tomas last year. it had repeated runs on that system. SLU the patois is good lol


lol. yeh.

Thr GFS has been very erratic this year so i'm sticking to the EURO
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I've seen some interesting posts in the years I've been here, some funny, some not, some that were intended to make people angry and succeeding and some that only caused a few raised eyeborws, but in all my time here, coming into the blog flatfooted with no context upon which to interpet a post, this one takes the cake:

"My favorite show on TV is Dora The Explorer. I watch it with my daughter almost every day."...excuse me, I have to clean the coffee off my screen now...

I have no explanation for why the mere mention of Dora the Explorer sends me into paroxysmal laughter; I have no idea, but nevertheless, thank you FrankZapper
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Quoting SLU:


Here you go hydrus

12z ECMWF
The 240 hour frame has a storm on or near the Cape Canaveral...
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Quoting AtHomeInTX:


Things looking a lot like last year steering wise. Big east coast trough. Of course that's far off. And timing is everything. Still definitely time to pay attention.


Timing is everything, and you may be right about this season setting up like last year's, but I find it unlikely the USA will go unscathed this season.
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SLU you are so correct. have more faith in the euro model than the rest. the euro model was the only one that nailed Tomas last year. it had repeated runs on that system. SLU the patois is good lol
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351. SLU
Quoting AtHomeInTX:


Things looking a lot like last year steering wise. Big east coast trough. Of course that's far off. And timing is everything. Still definitely time to pay attention.


... and if this system forms as the EURO is hinting then that will be bad news for the rest of the year since you don't normally get July storms in the deep tropics outside of extremely active seasons.
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Quoting SLU:


Here you go hydrus

12z ECMWF
Mucho Gracias...
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349. SLU
Quoting hydrus:
Could you provide that link please.?


Here you go hydrus

12z ECMWF
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Quoting SLU:


Things looking a lot like last year steering wise. Big east coast trough. Of course that's far off. And timing is everything. Still definitely time to pay attention.
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347. SLU
Quoting prcane4you:

Maybe they are death.



pe' chu-ou!
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Quoting FrankZapper:
My favorite show on TV is Dora The Explorer. I watch it with my daughter almost every day.


who knew Dora was a storm.....
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Quoting SLU:



yep
Maybe they are death.

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My favorite show on TV is Dora The Explorer. I watch it with my daughter almost every day.
Member Since: May 26, 2011 Posts: 0 Comments: 1193
goodbye troll
Member Since: July 15, 2006 Posts: 192 Comments: 59571
Quoting SLU:
Could you provide that link please.?
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341. SLU
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Quoting prcane4you:

Dry air ahead may delay development.


But not for long...
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Large line of showers and thunderstorms heading for the Lesser Antilles...
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338. SLU
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Quoting prcane4you:




Quoting SLU:
here we go again ...
Tw lovers,too excited.
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the wave in the catl is very large and will take sometime to consolidate. the apparent llc is at 11n 36w moving west. as long as the circulation continues to be weak ,it will travel west with the shallow steering currents. i cannot see this wave moving north of the islands, unless it is a stonger system. the only impediment to this system developing is the dry air to its northwest, however the system is so large that it will be able to create and envelope of moisture which will negate the effects of the dry air. no matter what happens the wave has the potential to organise,only that it will be slow to occur because of its large size
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Quoting KEEPEROFTHEGATE:


amazing how the mountains in calfornia hadso much snow this year and that theystill have snow.... they might have snow year around
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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