Dr. Jeff Masters' WunderBlog

U.S. heat wave blamed for 22 deaths; Bret and Cindy no threat
Posted by: Dr. Jeff Masters, 3:07 PM GMT on July 21, 2011 +8
The dangerous U.S. heat wave of July 2011 will continue to bring another day of exceptionally humid heat to over 100 million Americans today, with 33 states plus the District of Columbia currently under heat advisories. The heat index--how hot the air feels when factoring in both the temperature and the humidity--exceeded 100° in twenty states in the Central and Eastern U.S. on Wednesday, peaking at 123° in Council Bluffs, Iowa. At least 22 deaths are being blamed on the heat in the Midwest. The extreme humidity that has accompanied this heat has made it a very dangerous one, since the body is much less able to cool itself when the humidity is high. The high humidities are due, in great part, to the record rains and flooding in the Midwest over the past few months that have saturated soils and left farmlands flooded. Accompanying the heat has been high levels of air pollution, which also contributes to mortality. Air pollution is expected exceed federal standards and reach code orange, "Unhealthy for Sensitive Groups", in at least 22 states today, according to the latest forecasts from EPA.

The extreme heat peaked in Chicago yesterday, where the temperature hit 100° at Midway Airport and the Chicago Lakefront station. Rockford, Illinois hit 100°, the first time in 22 years that city had seen 100° temperatures. Detroit is expected to hit 100° for the first time in sixteen years today, and I think I'm going to skip the Ann Arbor Art Fair! New York City and the mid-Atlantic states are expected to be near 100° on Friday. The forecast high of 103° in Washington D.C. for Friday is just 3° below the hottest temperature ever recorded in the city, 106°. The heat will continue in the mid-Atlantic states through Sunday, then ease on Monday when a cold front is expected to pass through. Wunderground's climate change blogger Dr. Ricky Rood has some good insights on the current heat wave in his latest post. A few notable highlights from this week:

Omaha, Nebraska has been above 80° for a four-day period beginning on July 17. This is the 2nd longest such stretch on record, next to the 8-day period that ended July 25, 1934. Multi-day periods when the low temperatures do not cool off below 75° are associated with high heat wave death rates.

Amarillo, Texas recorded its 26th day of 100° temperatures yesterday, tying the city's record for most 100° days in a year, last set in 1953. Record keeping in the city goes back to 1892.

Minneapolis, Minnesota, recorded its highest dew point ever, 82°, on Tuesday. The heat index hit a remarkable 118° in the city, which tied July 11, 1966 for the highest heat index on record in the city. Minnesota's all-time highest dew point temperature of 86° was tied on Sunday, in Madison. The previous record was in St. James and Pipestone in July of 2005.

The latest National Weather Service storm summary has a list of cities where the heat index exceeded 100° yesterday.


Figure 1. On Wednesday, heat advisories for this dangerous heat wave covered portions of 33 states plus the District of Columbia, an area with 141 million people--about half the population of the U.S.

Tropical Storm Bret no threat
Tropical Storm Bret continues to struggle with high wind shear of 20 - 30 knots, and high shear is expected to affect the storm the remainder of the week. The combination of high wind shear and dry air nearby should act to destroy Bret by Sunday, and the storm is not a threat to any land areas.

Tropical Storm Cindy forms
Tropical Storm Cindy formed yesterday 600 miles to the east of Bermuda. Cindy's formation was 24 days ahead of the usual formation date for the third named storm of the Atlantic hurricane season, which is August 13. This year has the most early season activity since 2008, when Hurricane Dolly got named on July 20. Wind shear is a moderate 10 - 20 knots, and is expected to remain moderate for several days. However, Cindy has moved over cool ocean waters of 25°C this morning, and this temperature is 1.5°C below the threshold of 26.5°C that tropical storms typically need in order to maintain their strength. With Cindy predicted to move over waters of just 21°C by Friday morning, the storm doesn't have long to live. Cindy is not a threat to any land areas.

An African wave worth watching
An African wave near 12N 50W, 700 miles east of the Lesser Antilles Islands, is moving west to west-northwest at about 15 mph, and is generating a limited amount of heavy thunderstorms due to the presence of a large amount of dust and dry air from the Sahara. This wave will spread heavy rain showers and strong gusty winds to the northern Lesser Antilles beginning on Saturday. The wave has a modest degree of spin to it, and is under low wind shear, 5 - 10 knots. Once it finds a moister environment near the Bahama Islands early next week, it could develop. Of the latest 00Z and 06Z runs of the four reliable models for predicting formation of a tropical depression, only the NOGAPS model shows development of the wave. The NOGAPS predicts the wave could attain tropical depression status on Wednesday, just off the coast of South Carolina. The other models generally depict too much wind shear over the Bahamas for the wave to develop. The eventual track of the wave once it reaches the Bahamas early next week is uncertain; there will be a trough of low pressure located off the U.S. East Coast that will be capable of turning the wave to the north, along the East Coast. However, it is also quite possible that the wave would be too weak and to far south to feel the influence of this trough, and instead would enter the Gulf of Mexico.


Figure 2. Morning satellite image of Hurricane Dora.

Hurricane Dora in the Eastern Pacific close to Category 5
Hurricane Dora in the Eastern Pacific put on an impressive burst of intensification over the past 24 hours, and is now a very impressive Category 4 storm with 155 mph winds, just 1 mph short of Category 5 status. Dora is expected to move parallel to the coast of Mexico, and should not cause any major trouble in that country. Dora is the second major hurricane in the East Pacific this year; Hurricane Adrian topped out as a Category 4 storm with 140 mph winds in early June.

Think cold. Way cold!
Those of us sweltering in today's heat would do well to consider that on this date in 1983, Vostok, Antarctica shivered at -128°F--the coldest temperature ever measured on Earth. The low tonight in Vostok is expected to be a relatively balmy -80°F.

Jeff Masters
Categories: Heat
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352. AtHomeInTX 7:28 PM GMT on July 21, 2011    
Quoting duajones78413:
What is this about some blob and Texas?


I'd link it for you but my puter sux. The noon ECMWF doesn't develop the yellow circle blob but sends it this way. For this run. Lol.
Member Since: August 24, 2010 Posts: 0 Comments: 3887
354. Slamguitar 7:29 PM GMT on July 21, 2011    
Quoting WeatherNerdPR:

OK, HOW is it possible for it to be hotter in MICHIGAN than in Puerto Rico?


As a MI resident, I would also like an answer to this. Dewpoint just hit 80 in my parts. What a week it's been...
Member Since: July 2, 2011 Posts: 0 Comments: 1021
355. prcane4you 7:29 PM GMT on July 21, 2011    

Quoting MrstormX:


People who care about meteorological processes more then watching TCs make landfall.
Landfalls a meteorological process more interesting than a fish storm.
Member Since: June 23, 2011 Posts: 0 Comments: 277
356. PalmBeachWeatherBoy 7:30 PM GMT on July 21, 2011    
quick-curious question about the "heat wave": Why are their never any heat advisories in florida? is it because temperatures this high (it is currently 94 degrees with 104 degree heat index in west palm beach)are not far from normal?

also in the winter, florida receives similar "cold weather advisories" when wind chills reach the 30's but northern states do not.
Member Since: August 30, 2006 Posts: 1 Comments: 433
357. Neapolitan 7:31 PM GMT on July 21, 2011    
Quoting SuperYooper:


Ask people who live in Hell, MI.

According to the NWS, Hell, MI, has only reached 97 so far today. Ann Arbor, then, truly is hotter than Hell.
Member Since: November 8, 2009 Posts: 4 Comments: 11166
359. tkeith 7:33 PM GMT on July 21, 2011    
Quoting Neapolitan:

According to the NWS, Hell, MI, has only reached 97 so far today. Ann Arbor, then, truly is hotter than Hell.
New Orleans, Louisiana (Airport)
Updated: 39 min 23 sec ago
92 °F Scattered Clouds
Humidity: 52%
Dew Point: 72 °F
Wind: 4 mph from the North

well at least New Orleans aint hotter than Hell...
Member Since: November 1, 2004 Posts: 25 Comments: 8839
360. SuperYooper 7:34 PM GMT on July 21, 2011    
Quoting Neapolitan:

According to the NWS, Hell, MI, has only reached 97 so far today. Ann Arbor, then, truly is hotter than Hell.


I was under the impression that only happened when the Wolverines lost football games. I was proven wrong again.

LOL Nea.
Member Since: August 18, 2010 Posts: 14 Comments: 1591
362. mrpuertorico 7:34 PM GMT on July 21, 2011    
Quoting WeatherNerdPR:

OK, HOW is it possible for it to be hotter in MICHIGAN than in Puerto Rico?


well we are lucky enough to have the trade winds sweep in cool air during the summer from the Atlantic ocean it does get bad here when the wind comes from the south (caribbean) that water is hot so the wind comes in hot hope that helps. God bless the trade winds!!!
Member Since: July 10, 2006 Posts: 0 Comments: 833
363. islander101010 7:35 PM GMT on July 21, 2011    
not much convection with the tropical wave yet lets see if it likes warmer water tomorrow.
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364. yonzabam 7:35 PM GMT on July 21, 2011    
Quoting PalmBeachWeatherBoy:
quick-curious question about the "heat wave": Why are their never any heat advisories in florida? is it because temperatures this high (it is currently 94 degrees with 104 degree heat index in west palm beach)are not far from normal?

also in the winter, florida receives similar "cold weather advisories" when wind chills reach the 30's but northern states do not.


I live in a very cool part of the world, but I know heat advisories are mainly aimed at people not acclimatised to extreme heat. Those are the ones most likely to die.

So, Michigan may issue heat advisories even though expected temps there are below those expected in Florida or Texas.
Member Since: July 20, 2008 Posts: 0 Comments: 1734
365. SuperYooper 7:36 PM GMT on July 21, 2011    
Quoting DestinJeff:


"You gotta let your boys breathe, Jerry!"


LMAO!
Member Since: August 18, 2010 Posts: 14 Comments: 1591
367. Some1Has2BtheRookie 7:37 PM GMT on July 21, 2011    
Quoting Neapolitan:

According to the NWS, Hell, MI, has only reached 97 so far today. Ann Arbor, then, truly is hotter than Hell.


LOL +10
Member Since: August 24, 2010 Posts: 0 Comments: 4104
370. ncstorm 7:38 PM GMT on July 21, 2011    
Quoting Neapolitan:

According to the NWS, Hell, MI, has only reached 97 so far today. Ann Arbor, then, truly is hotter than Hell.


LOL!!
Member Since: August 19, 2006 Posts: 7 Comments: 8468
371. CaicosRetiredSailor 7:38 PM GMT on July 21, 2011    
Giant Earth Fart Triggered Mass Extinctions, Spurring Rise of Dinosaurs: Study

July 21, 2011 3:27 PM EDT

A huge release of methane gas may have triggered the prehistoric mass extinctions that allowed dinosaurs to become the dominant life form on earth, according to a new study.

About 201 million years ago, half of known species vanished in an event that signaled the end of the Triassic period and created the lack of natural competition necessary for the ascendance of dinosaurs. The oldest known dinosaur fossiles date back Fto about 230 million years ago, but they do not take over until about 30 million years later....

http://www.ibtimes.com/articles/184628/20110721/m ethane-burp-methane-fart-methane-release-mass-exti nction-climate-change-carbon-dioxide.htm
Member Since: July 12, 2007 Posts: 0 Comments: 5133
373. mrpuertorico 7:41 PM GMT on July 21, 2011    

Actually the SST's are higher ahead of the wave so yeah hoter water
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374. mrpuertorico 7:42 PM GMT on July 21, 2011    
ok the blog is acting funny again quoting people i dont want to quote lol
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375. ncstorm 7:43 PM GMT on July 21, 2011    
HPC Sea Level Pressures and Fronts.3-7 day forecast

Member Since: August 19, 2006 Posts: 7 Comments: 8468
377. HurricaneDean07 7:45 PM GMT on July 21, 2011    
My forecast for the 5 pm update:
Bret:
40 mph
1006 MB
NE to ENE at 11 mph

Cindy:
65 Mph
995 MB
NNE at 30 mph
Member Since: October 3, 2010 Posts: 39 Comments: 4053
378. KeysieLife 7:45 PM GMT on July 21, 2011    
Quoting DestinJeff:
Somebody alert the Storm Whisperer (ike)! We may need his skills in about a week or so.
We all need to BE SAFE!
Member Since: September 10, 2010 Posts: 2 Comments: 359
379. BaltOCane 7:45 PM GMT on July 21, 2011    

View Options
Baltimore WeatherSave This Location Updated: Jul 21, 2011, 3:25pm EDTUPDATE DATANearby TruPoint Locations: Baltimore-Washington I... | Mt. Royal Cultural Cen...


Partly Cloudy
Extreme heat index. Outdoor exposure should be limited.
Clear Mostly Sunny Isolated T-Storms
103°F
Feels Like: 118°

Oy, I know this is what Baltimore feels like in the summer, but this is crazy. And August isn't even here yet!

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380. HurricaneDean07 7:46 PM GMT on July 21, 2011    
Be back later...
Member Since: October 3, 2010 Posts: 39 Comments: 4053
381. winter123 7:46 PM GMT on July 21, 2011    
-80 sounds pretty good right now. These popcorn storms like bret and Cindy make me nervous cause later in the season they will move west, not east.
Member Since: July 29, 2006 Posts: 28 Comments: 1700
385. 47n91w 7:48 PM GMT on July 21, 2011    
Quoting yonzabam:


I live in a very cool part of the world, but I know heat advisories are mainly aimed at people not acclimatised to extreme heat. Those are the ones most likely to die.

So, Michigan may issue heat advisories even though expected temps there are below those expected in Florida or Texas.


A cold front moved through last night across Lake Superior and has brought drier air and cooler temps to the region. 82 degrees for a high today after 97 degrees yesterday and a heat index of 113. I was under a Excessive Heat Warning for the last five days. My local NWS office uses this criteria for issuing excessive heat warnings:

issued for a 24-hour period where the heat index exceeds 110 for 3 hours or more during daytime and statys at or above 80 at night

I know some offices tweak their guidelines for things like windchill and winter storm criteria. I wonder if the criteria for heat is the same?
Member Since: August 13, 2009 Posts: 0 Comments: 230
386. CybrTeddy 7:48 PM GMT on July 21, 2011    
Cindy has been sporting an eye all morning, as such if it was closer to land it would probably be a hurricane.
Member Since: July 8, 2005 Posts: 253 Comments: 20262
387. BaltOCane 7:48 PM GMT on July 21, 2011    
Baltimore, Inner Harbor
Lat: 39.28 Lon: -76.61 Elev: 19
Last Update on Jul 21, 2:54 pm EDT


NA

103 °F
(39 °C) Humidity: 41 %
Wind Speed: Calm
Barometer: 29.80" (1009.1 mb)
Dewpoint: 75 °F (24 °C)
Heat Index: 117 °F (47 °C)
Visibility: 0.00 mi.
More Local Wx: 3 Day History:


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389. nigel20 7:49 PM GMT on July 21, 2011    
Member Since: November 6, 2010 Posts: 2 Comments: 4544
390. KeysieLife 7:51 PM GMT on July 21, 2011    
Quoting DestinJeff:
378 ...

yeah forgot about that. Or is STAY SAFE? I never can remember.
Depends on the weather, and if there are cashews involved...
Member Since: September 10, 2010 Posts: 2 Comments: 359
394. KeysieLife 7:56 PM GMT on July 21, 2011    
Quoting P451:
As the huge stubborn high continues to bake the US in heat....


Sheesh, this sounds like we've got an after-school special "When Weather, Gone Wild"
Member Since: September 10, 2010 Posts: 2 Comments: 359
395. weathermanwannabe 7:58 PM GMT on July 21, 2011    
Quoting PalmBeachWeatherBoy:
quick-curious question about the "heat wave": Why are their never any heat advisories in florida? is it because temperatures this high (it is currently 94 degrees with 104 degree heat index in west palm beach)are not far from normal?

also in the winter, florida receives similar "cold weather advisories" when wind chills reach the 30's but northern states do not.


Tallahassee NWS did issue heat advisories a few weeks ago when we had a string of several really hot days here and D. M mentioned it in one his blogs; our Airport had a record 105 reading on that particular afternoon.................The typical advisory then talks about hydration and outside activities in the early morning/late evening, etc....
Member Since: August 8, 2006 Posts: 0 Comments: 6702
396. nigel20 7:59 PM GMT on July 21, 2011    
Member Since: November 6, 2010 Posts: 2 Comments: 4544
397. TomTaylor 8:00 PM GMT on July 21, 2011    
x
Member Since: August 24, 2010 Posts: 18 Comments: 3904
399. weaverwxman 8:02 PM GMT on July 21, 2011    
Even though Florida is HOT today in the 90's with hunidity at near 100% and dewpoints in the 70 and 80's because it has oceans on both sides albeit the oceans are relatively warm the sea breeze does help control our tempuratures. We have afternoon t-storms usually on one side of the state on any given day because of the sea breeze. Temps after and sometimes before a t-storm drop very sharply sometimes into the 70's. It is very dynamical weather in So Fla especially. I will miss this when I leave here. I think....
Member Since: November 17, 2009 Posts: 0 Comments: 332
400. DFWjc 8:04 PM GMT on July 21, 2011    
Quoting prcane4you:

Who cares about Cindy?


The people in the Iceland or the British Isles
Member Since: July 19, 2011 Posts: 1 Comments: 967
401. midgulfmom 8:05 PM GMT on July 21, 2011    
Ummm...Hello...This is Alice. Am I in wonderland or wunderground, or both?
Member Since: July 9, 2005 Posts: 2 Comments: 1002

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About JeffMasters
Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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