A heat wave recap; generally quiet tropics

By: Dr. Jeff Masters , 4:45 PM GMT on July 25, 2011

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Last week's U.S. heat wave has finally subsided, and most of the Northeast will see some cool highs in the 70s today. Unfortunately, the Midwest, and mid-Atlantic will continue to see high temperatures in the 90s for the rest of this week, and the southern Plains will be forced to continue to endure triple-digits.

According to the National Climatic Data Center (NCDC), 2,100 daily high maximum temperature records have been set so far in July 2011, and 51% of those were set last week. 4,734 daily high minimum temperature records have been set so far this month, and 55% of those were set last week. Here's a breakdown of last week's records for the period July 18 through July 24:

High Maximum:

• 1,076 warmest maximum temperature for the date
• 90 warmest maximum temperature for the month of July
• 56 warmest maximum temperature of all time

High Minimum:

• 2,595 warmest minimum temperature for the date
• 207 warmest minimum temperature for the month of July
• 123 warmest minimum temperature of all time

The number of warm minimum temperatures is especially disturbing, as these tend to have more of an impact on health than the high maximums. When the temperature remains high at night, it prevents the body from being able to recover from the day's heat. According to NOAA, from July 1 through July 19, there were 22 heat-related deaths in the United States. Reuters is reporting that 34 deaths resulted from this heat wave. In an average year, heat remains the number one weather-related killer in this country. In some ways, the overnight low temperatures are the best way to quantify a heat wave, possibly even better than the heat index.


Figure 1. Map of daily high maximum temperature records for the period July 1 through July 25 from NCDC. Red circles without an X denote a broken record; red circles with an X denote a tied record.

Tropical Overview

The wave formerly known as Invest 90L

The wave formerly known as Invest 90L is moving slowly west through the Caribbean near Jamaica. A new burst of convection started this morning, which will undoubtedly produce some heavy rain over southern Cuba and Jamaica. While low-level circulation has remained about the same since late last week, the wave has become top-heavy with increased circulation at higher levels (700-500mb). None of the models (GFS, ECMWF, CMC, NGPS, UKMET) are developing this wave as tracks into the Gulf of Mexico, and they're all in agreement that the path will be toward far southern Texas or northern Mexico, except for the ECMWF deterministic run, which hints that it will take a turn toward the northern Gulf. However, this model hasn't shown actual development from the wave since Tuesday or Wednesday of last week.

NHC has dropped this invest as of Saturday afternoon, but it remains on their radar. They're giving the wave a 0% chance to form over the next 48 hours. Given the recent uptick in mid-level circulation, I'd imagine they're still a little concerned about the potential for this wave to fire-up again once it's in the Gulf, and it will surely be of concern for Cuba as it tracks westward. However, given the lack of model support for almost 7 days in a row now, I'd say this wave has seen its glory come and go.


Figure 2. Visible tropical Atlantic satellite captured at 11:14am EDT on Monday.

Other North Atlantic waves

There are a couple other waves to speak of that have left the coast of Africa in the past few days, one located near 40W and the other closer to Africa, around 30W, which is tangled up in the monsoon trough. The former is expected to take a southerly track, skirting northern South America, and possibly into the Bay of Campeche. Given this track, none of the models are suggesting it will develop. However, tropical cyclones that spin up in the Bay of Campeche generally have a short forecast lead time, so it's something to watch. The latter wave could take a slightly more northern track through the Caribbean islands, and a couple of the models seem to favor this wave for development at the end of their runs.

Tropical wave activity has been lacking so far this season, but climatologically we should see an increase in African easterly waves in August and September.

Angela

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1956. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128648
Quoting Tazmanian:
poll time

what will 90L be at 2pm


A 30%

B 40%

C 50%

D higher

E the chart


I'm thinking E

The CHART....

Member Since: Posts: Comments:
1949. hydrus
Does not look like it is moving very fast...
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For hours and hours watching a tropical wave to grow.This blog is the bigger NHC i ever seen.
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Without surface convergence the current convection will collapse in due time.
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If this storm takes the most northern computer model looks like Texas will be in for it. Wow,from drought to flash flooding that ain't good!
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Quoting hydrus:
lol...Time to speed my wings in the face of St Peters air space...



there she is
Member Since: May 21, 2006 Posts: 5091 Comments: 115239
1942. Matt74
Quoting P451:






Looks pretty good to me. Why no SSD or Rammb floaters for it? Found RAMSDIS regional floater for it but not storm relative. NRL has it. NHC is still stubborn only giving it 20% now. What are they doing? "saving face" because of their 0% last night minutes before reactivating 90L? So they'll do what up it slowly lol? Makes no sense. This system looks good.



P451.. Where do you think the coc is? just curious on what you are thinking. Thanks
Member Since: Posts: Comments:
Quoting FLdewey:

Could be... it's sneaking into prime time territory for sure.

Everyone keep an eye out for strange ant movement.


Haha, you know something's going down when the ants are running away.
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Is it me or did the dash line get longer at the end?

Member Since: August 23, 2008 Posts: 0 Comments: 1918
1936. hydrus
Quoting DestinJeff:
Hydrus, with all the good you have done simply by alerting people to 100-yr trends of hurricane activity I'm sure you will be just fine.

Unless Taz is St Peter.
lol...Time to speed my wings in the face of St Peters air space...
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1935. ackee
we are going into AUG seem like some models are weaken the HIGH and most model arent deloping any storms yet maybe 2011 might not end up to be a bad year after all I hope.
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Complete Update

TS BUSTED FORECAST ALIBI





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Quoting ackee:
what will become of the 90L

A TD
B TS
c STRONG LOW
D REMAIN AN INVEST
More polls.
Member Since: Posts: Comments:

Quoting Tazmanian:
poll time

what will 90L be at 2pm


A 30%

B 40%

C 50%

D higher

E the chart
Ask NHC.
Member Since: Posts: Comments:
some one plzs post the be loveing chart it will help us tell where 90L will go
Member Since: May 21, 2006 Posts: 5091 Comments: 115239
1927. ackee
what will become of the 90L

A TD
B TS
c STRONG LOW
D REMAIN AN INVEST
Member Since: Posts: Comments:
1926. Buhdog
Quoting P451:


This thing has never liked the 850mb level. Yet it has more 850mb vort than I've ever seen it have. It looks good to me.



200/500/750/850 vort




It is continuing to fight some mid-level shear. Deep layer shear looks to be okay for now.



mid/deep shear





It once again is devoid of surface convergence - something that has plagued this system forever.

converge/diverge



slower speed should help that no? 90l is really giving the nhc the business right now.
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1924. WxLogic
Good Morning...
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Quoting neutralenso:
Lets all be honest! Am i the only one who had faith in 90L? i mean when is disspated by the islands to when it got ripped apart over Hispanola to it now i always said this blob would try to develop somewhere down the road and here we are today :) anyone else though like me?
Having faith in a tropical wave?Wow I wonder if FAITH is for that.Some people likes faith in bad things.
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1922. hydrus
This is sorta interesting..NOGAPS showing a swath of precip probably from 90L..
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Quoting FLdewey:

Could be... it's sneaking into prime time territory for sure.

Everyone keep an eye out for strange ant movement.


We took out the ants last night..boiling water, etc. I have no ants to watch! Doom!
Member Since: Posts: Comments:
Quoting P451:


This thing has never liked the 850mb level. Yet it has more 850mb vort than I've ever seen it have. It looks good to me.



200/500/750/850 vort




It is continuing to fight some mid-level shear. Deep layer shear looks to be okay for now.



mid/deep shear





It once again is devoid of surface convergence - something that has plagued this system forever.

converge/diverge



Ah that is so cool!
Member Since: August 23, 2008 Posts: 0 Comments: 1918
1917. Jax82
Quoting Tazmanian:
poll time

what will 90L be at 2pm


A 30%

B 40%

C 50%

D higher

E the chart


E. The chart, because you love it so much!
Member Since: Posts: Comments:
1910. hydrus
Quoting FLdewey:

Look at that huge hole in Florida. Oh man this is not good. 2012 is upon us!!!
Good mornin Dewey..yes 12/21/12 will be here right soon..I hope my affiliation with The Almighty is in good order...:)
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Quoting breeezee:
in reality the nhc is not giving 90L much of a chance to do anything but stay at blob status are maybe blob1


LOL; blob1 looks alitte stronger then dat this morning
maybe blob 2 or 3, what are the blob catagorys anyway?
Member Since: August 23, 2008 Posts: 0 Comments: 1918
Good Morning.
I see 90L got better. Still can't see much of a surface circulation, but at least it's something.
Member Since: Posts: Comments:
poll time

what will 90L be at 2pm


A 30%

B 40%

C 50%

D higher

E the chart
Member Since: May 21, 2006 Posts: 5091 Comments: 115239

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