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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Quoting TampaSpin:
Time for Dinner..........will be on late tonite for an update .........gotta a lot more out there besides 90L to start watching!


beating a dead horse has come to mind more than twice.

Basically, right now, I don't think 90L has a deep enough vortex to go significantly northward, though depending on how long this weakness hangs around, it could assuming the vortex gains some vertical integrity while traversing the Gulf. -- Korintheman

This makes sense, thanks.
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This is "current" [more or less]:




This is tomorrow morning:



This is 24 hours from now:



I think NHC is expecting some short-term moderation of the high... but long term impact seems to be amelierated by the high building back in later in the week...

I suggest u go look yourself... interesting low pressure showing up at about 50W by the weekend....
Member Since: October 25, 2005 Posts: 19 Comments: 21570
Quoting TropicalAnalystwx13:
Who thinks that 90L will fizzle out tonight?
It has a center currently located just between Cayman & Jamaica in some very warm ocean heat content. I doubt it would totally fizzle out, but most likely continue to progress slowly in further development, just my opinion of course here. Had some ominous squalls lining up here today, but not a lot of rain.Heavy overcast now but still not much in rainfall. Have a good night everyone.
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Quoting bobbbo:
It must be the heat…well, of course it is, and this dad-gummed drought, too.
I finally have to send a note to my WU comrades.
I’ve lurked here for years and soaked up so much info that now I can actually understand 70% of the charts and have a feel for your unique, singular, and interesting personalities.
Also, I can’t count how many photos I’ve used over the years as my desktop background and have sent to my loved ones pertinent to their home towns.
WU has been the nicest thing to come my way since folding money and at this time I’m gonna ask y’all to do just one little thing for me…

Here in central TX (Austin), we are having a worse summer than 2009.
If it's not too much trouble, what I’d like everybody to do, is at 1700Z on 7/27, is a teensey little group rain dance.

No…nothing spectacular with any smoke and feathers… maybe just get up from your office chair, throw your hands over your head, dance around that chair, sing up to the acoustic ceiling …
”PLEASE MOTHER NATURE BRING A LITTLE BLESSED RAIN TO THE POOR SOULS AND ANIMALS IN GOD’S OWN COUNTRY, TEXAS, AMEN!

If that’s a little much then you can leave out the AMEN.

Thank you most kindly.
AMEN

I have done about 1,000 rain dances in the past 10 months. :) You want to get real depressed drive to West Texas and Back from South Central Texas, the Land is Devastated and there are still thousands of animals trying to survive with No water and little to No food. I just got back, it is the worst i have seen in my 53 years of living in Texas. Temps are averaging 105 for highs the past several days so having a systme that even may come here is Positive News but I will not get excited until it is raining.
Member Since: July 5, 2009 Posts: 0 Comments: 1348
Link

Member Since: June 9, 2007 Posts: 4 Comments: 15790
Quoting louisianaboy444:


Well beings that it is shortwaves perubations they will be more pronounced at 500mb but can this still overall affect the orientation and strength of the ridge?


My point was that, regardless of the wavelength of the respective impulses, yesterday's models pointed toward the ridge being weakest at 500 mb. As a rule, a deeper vortex tends to travel more poleward, as the Bermuda/Azores high is typically weaker at the mid levels than the lower ones, hence why weaker systems tend to travel westward within the lower tropospheric flow despite the mid-level flow being weaker.

Basically, right now, I don't think 90L has a deep enough vortex to go significantly northward, though depending on how long this weakness hangs around, it could assuming the vortex gains some vertical integrity while traversing the Gulf.
Member Since: March 7, 2007 Posts: 558 Comments: 20000
Time for Dinner..........will be on late tonite for an update .........gotta a lot more out there besides 90L to start watching!
Member Since: September 2, 2007 Posts: 178 Comments: 20439
1249. Patrap
If you switch to FireFox as a Browser, it automatizes those bad HTML sized images.

Most if not all scripts here are developed with FF in mind
Member Since: July 3, 2005 Posts: 421 Comments: 127647
Quoting jeebsa:
Some of the images posted on here stretch the screen if you hide them after viewing them it fixes itself It works for internet explorer and my Evo


The F5 button usually works for me.
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1247. Patrap
Tropical Cyclone Heat Potential




Depth 26.C Isotherm

Member Since: July 3, 2005 Posts: 421 Comments: 127647
1246. jeebsa
Some of the images posted on here stretch the screen if you hide them after viewing them it fixes itself It works for internet explorer and my Evo
Quoting TropicalAnalystwx13:


Get firefox or google chrome.

There needs to be a message at the top that says this. Seems like A LOT of people are having this problem.
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Quoting TropicalAnalystwx13:


Yeah, sure, but has 90L ever shown any real organization before now?


No but you're assuming a lot.
LinkIRLoopCarib

If it goes clear west then it will run into Yucatan.
But there is an anticyclone over there so who knows.
North it hits Cuban mountains and oh yeah a ridge.
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It's possible the GFDL and HWRF aren't run for 90L tonight due to it's poor organization.
Member Since: June 9, 2007 Posts: 4 Comments: 15790
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting louisianaboy444:
Question: How do you stretch the blog..its cutting off the end of people's posts
The only solution I came up with was to use smaller Fonts
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Quoting Tropicsweatherpr:
Now we wait for the 00z run from GFDL and HWRF. GFDL has been good so far this year.


When do they come out?
Member Since: July 6, 2010 Posts: 113 Comments: 31547
1240. Patrap
00z Early Cycle NHC model tracks
Invest90
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)





Member Since: July 3, 2005 Posts: 421 Comments: 127647
Who thinks that 90L will fizzle out tonight?
Member Since: July 6, 2010 Posts: 113 Comments: 31547
Quoting KoritheMan:


As far as the weakness is concerned, that would in theory be able to bend it more poleward, but according to yesterday's set of model runs, the height of the weakness was confined to the 500 mb level.

Don't know about today's runs, though. I'm in the process of analyzing things right now.


Well beings that it is shortwaves perubations they will be more pronounced at 500mb but can this still overall affect the orientation and strength of the ridge?
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Quoting EasttexasAggie:
850 is tightening up. Wondering what the surface winds are showing.



yes the 850 is matching up and i think its about to get rollin
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Quoting louisianaboy444:
Question: How do you stretch the blog..its cutting off the end of people's posts


Get firefox or google chrome.

There needs to be a message at the top that says this. Seems like A LOT of people are having this problem.
Member Since: July 6, 2010 Posts: 113 Comments: 31547
Quoting stormwatcherCI:
+1 You took the words right out of my mouth.


I agree right or wrong, I like someone who's not afraid to go out on a limb!
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Quoting Chicklit:

NHC has gone from 20% to 10% to 0% over the past 4 days. And there are more interesting features to watch out east, coming from Cape Verde.
At this point, it may make it to Yucatan and Mexico in its present state, but what do I know. Nuthin.
Agreed. I'm still waiting to see if it still looks like anything in the a.m. I've seen this fizzle too many times to be excited just yet. And IMO to make the GoM crossing, it needs more than just a moisture envelope....
Member Since: October 25, 2005 Posts: 19 Comments: 21570
Quoting BahaHurican:
Hmm.... don't know about that curry... unless you mean the Vindaloo red curry... regular West Indian style might not work as well...

I'd be in line for the Jerk or stormwatchers curry crow myself, but decided this morning to hold off on joining the 'RIP 90L' band-wagon, good thing LOL ?
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Question: How do you stretch the blog..its cutting off the end of people's posts
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Now we wait for the 00z run from GFDL and HWRF. GFDL has been good so far this year.
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1230. yoboi
Quoting alluvion1134:
I'm glad 90L is back. Our good friends in Texas need the rain in a major way.
i think it will hitt fla
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Quoting louisianaboy444:


I see your point but the southern end of this ridge is rather suspect right now with energy from the North creating several weaknesses in it, thus the showers and thunders over LA today...if your indeed correct though i can see this system increasing in forward speed and bending westward once in the SE Gulf


As far as the weakness is concerned, that would in theory be able to bend it more poleward, but according to yesterday's set of model runs, the height of the weakness was confined to the 500 mb level.

Don't know about today's runs, though. I'm in the process of analyzing things right now.
Member Since: March 7, 2007 Posts: 558 Comments: 20000
Quoting bobbbo:
It must be the heat…well, of course it is, and this dad-gummed drought, too.
I finally have to send a note to my WU comrades.
I’ve lurked here for years and soaked up so much info that now I can actually understand 70% of the charts and have a feel for your unique, singular, and interesting personalities.
Also, I can’t count how many photos I’ve used over the years as my desktop background and have sent to my loved ones pertinent to their home towns.
WU has been the nicest thing to come my way since folding money and at this time I’m gonna ask y’all to do just one little thing for me…

Here in central TX (Austin), we are having a worse summer than 2009.
If it's not too much trouble, what I’d like everybody to do, is at 1700Z on 7/27, is a teensey little group rain dance.

No…nothing spectacular with any smoke and feathers… maybe just get up from your office chair, throw your hands over your head, dance around that chair, sing up to the acoustic ceiling …
”PLEASE MOTHER NATURE BRING A LITTLE BLESSED RAIN TO THE POOR SOULS AND ANIMALS IN GOD’S OWN COUNTRY, TEXAS, AMEN!

If that’s a little much then you can leave out the AMEN.

Thank you most kindly.
AMEN



Sure, no problem.

You guys will get rain eventually, I know you will.
Member Since: July 6, 2010 Posts: 113 Comments: 31547
Quoting louisianaboy444:
Interesting that the EURO and 18Z GFS both send this system more Northwestward after entering the gulf where the Euro is pushing much needed rainfall into the big bend of Texas and the GFS hinting at the TX/La border...thats two pretty big outliers there
Was about to post that the extensive high that has been driving 90L due west is forecast to shift eastward under the influence of an admittedly weak trough tomorrow and Wed. [Well that was yesterday... haven't looked at the high forecast so far today.] So I'd expect some northerly component to 90L's movement to be built in, even if it eventually ends up on the W coast of the GoM... Hopefully the result is some much needed rain for TX, but without the unneeded hurricane impact...
Member Since: October 25, 2005 Posts: 19 Comments: 21570
All in all i still only forsee about a 20% chance of developing as of now although i am not too big on percentages. I would not be surprised if this looks way better by morning though. 90L might have a few more tricks up its sleeve.
Member Since: Posts: Comments:
Quoting bobbbo:
It must be the heat…well, of course it is, and this dad-gummed drought, too.
I finally have to send a note to my WU comrades.
I’ve lurked here for years and soaked up so much info that now I can actually understand 70% of the charts and have a feel for your unique, singular, and interesting personalities.
Also, I can’t count how many photos I’ve used over the years as my desktop background and have sent to my loved ones pertinent to their home towns.
WU has been the nicest thing to come my way since folding money and at this time I’m gonna ask y’all to do just one little thing for me…

Here in central TX (Austin), we are having a worse summer than 2009.
If it's not too much trouble, what I’d like everybody to do, is at 1700Z on 7/27, is a teensey little group rain dance.

No…nothing spectacular with any smoke and feathers… maybe just get up from your office chair, throw your hands over your head, dance around that chair, sing up to the acoustic ceiling …
”PLEASE MOTHER NATURE BRING A LITTLE BLESSED RAIN TO THE POOR SOULS AND ANIMALS IN GOD’S OWN COUNTRY, TEXAS, AMEN!

If that’s a little much then you can leave out the AMEN.

Thank you most kindly.
AMEN



OK Done and I mean "No Problem"

I hope it helps you all out :o)


Taco :o)
Member Since: Posts: Comments:
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting bobbbo:
It must be the heat…well, of course it is, and this dad-gummed drought, too.
I finally have to send a note to my WU comrades.
I’ve lurked here for years and soaked up so much info that now I can actually understand 70% of the charts and have a feel for your unique, singular, and interesting personalities.
Also, I can’t count how many photos I’ve used over the years as my desktop background and have sent to my loved ones pertinent to their home towns.
WU has been the nicest thing to come my way since folding money and at this time I’m gonna ask y’all to do just one little thing for me…

Here in central TX (Austin), we are having a worse summer than 2009.
If it's not too much trouble, what I’d like everybody to do, is at 1700Z on 7/27, is a teensey little group rain dance.

No…nothing spectacular with any smoke and feathers… maybe just get up from your office chair, throw your hands over your head, dance around that chair, sing up to the acoustic ceiling …
”PLEASE MOTHER NATURE BRING A LITTLE BLESSED RAIN TO THE POOR SOULS AND ANIMALS IN GOD’S OWN COUNTRY, TEXAS, AMEN!

If that’s a little much then you can leave out the AMEN.

Thank you most kindly.
AMEN



Can do!
Member Since: March 7, 2007 Posts: 558 Comments: 20000
This 90L is headed to the area where Camille blew up from nothing to the strongest ever to make landfall back in 69.
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Quoting TropicalAnalystwx13:


I agree with you about the broad nature of the circulation, but that has plenty of time to tighten up. Shear won't be a problem:

SHEAR (KT) 19 20 19 7 10 10 1 11 5 12 10 12 3


If you took that from SHIPS, I've seen it wrong before. Rarely are two models identical in their respective vertical shear forecasts.
Member Since: March 7, 2007 Posts: 558 Comments: 20000
anyway, goodnight. 90L is a sleeper except it's dropping a lot of rain. that's it.
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Quoting Chicklit:

NHC has gone from 20% to 10% to 0% over the past 4 days. And there are more interesting features to watch out east, coming from Cape Verde.
At this point, it may make it to Yucatan and Mexico in its present state, but what do I know. Nuthin.


Yeah, sure, but has 90L ever shown any real organization before now?
Member Since: July 6, 2010 Posts: 113 Comments: 31547
Quoting TropicalAnalystwx13:


I agree with you about the broad nature of the circulation, but that has plenty of time to tighten up. Shear won't be a problem:

SHEAR (KT) 19 20 19 7 10 10 1 11 5 12 10 12 3



Yes Shear drops under 20Kts it appears here!


Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting stormwatcherCI:
I suggested curry .
Hmm.... don't know about that curry... unless you mean the Vindaloo red curry... regular West Indian style might not work as well...

Member Since: October 25, 2005 Posts: 19 Comments: 21570
Quoting KoritheMan:


What, you think I don't have a reason other than being bored by this one? Come on, Cody! ;)

Seriously though, it's because the the GFS keeps some unfavorable upper-level easterlies (20 to 30 kt) associated with the eastern United States ridge over the Gulf for the next 48-60 hours, which may not allow much in the way of organization. Another factor is the broad nature of the circulation, which was never well organized.


I see your point but the southern end of this ridge is rather suspect right now with energy from the North creating several weaknesses in it, thus the showers and thunders over LA today...if your indeed correct though i can see this system increasing in forward speed and bending westward once in the SE Gulf
Member Since: Posts: Comments:
1214. bobbbo
It must be the heat…well, of course it is, and this dad-gummed drought, too.
I finally have to send a note to my WU comrades.
I’ve lurked here for years and soaked up so much info that now I can actually understand 70% of the charts and have a feel for your unique, singular, and interesting personalities.
Also, I can’t count how many photos I’ve used over the years as my desktop background and have sent to my loved ones pertinent to their home towns.
WU has been the nicest thing to come my way since folding money and at this time I’m gonna ask y’all to do just one little thing for me…

Here in central TX (Austin), we are having a worse summer than 2009.
If it's not too much trouble, what I’d like everybody to do, is at 1700Z on 7/27, is a teensey little group rain dance.

No…nothing spectacular with any smoke and feathers… maybe just get up from your office chair, throw your hands over your head, dance around that chair, sing up to the acoustic ceiling …
”PLEASE MOTHER NATURE BRING A LITTLE BLESSED RAIN TO THE POOR SOULS AND ANIMALS IN GOD’S OWN COUNTRY, TEXAS, AMEN!

If that’s a little much then you can leave out the AMEN.

Thank you most kindly.
AMEN

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Quoting TropicalAnalystwx13:
Just a question for the ones who do not believe 90L will develop.

What is your reasoning behind this?

NHC has gone from 20% to 10% to 0% over the past 4 days. And there are more interesting features to watch out east, coming from Cape Verde.
At this point, it may make it to Yucatan and Mexico in its present state, but what do I know. Nuthin.
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One thing is for certain......90L is not deprived of moisture.......there is plenty in the area.



Member Since: September 2, 2007 Posts: 178 Comments: 20439
Thank you!Tampa
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Quoting KoritheMan:


What, you think I don't have a reason other than being bored by this one? Come on, Cody! ;)

Seriously though, it's because the the GFS keeps some unfavorable upper-level easterlies (20 to 30 kt) associated with the eastern United States ridge over the Gulf for the next 48-60 hours, which may not allow much in the way of organization. Another factor is the broad nature of the circulation, which was never well organized.


I agree with you about the broad nature of the circulation, but that has plenty of time to tighten up. Shear won't be a problem:

SHEAR (KT) 19 20 19 7 10 10 1 11 5 12 10 12 3
Member Since: July 6, 2010 Posts: 113 Comments: 31547
Quoting louisianaboy444:


I dont know if you seen my post earlier but some of the factors going into this is that the airmass around the system is becoming more and more unstable...What looks like some sort of upper level perbuation is ushering in cooler air in the upper levels along with this wave approaching very high TCHP and water temps which will all but increase buoyant energy and thus evaporation which will all but increase lapse rates and instability..It also looks like these system is starting to show some signs of 750-800mb spin and working down it will only take a little forced lifting such as an outflow boundary from Cuba's dying storms to start the convection process...I am not saying it will develop but i do expect it to have a good night...IMO


Yeah, you're correct about the instability. I was kind of expecting it to encounter better relative humidity values as it entered this general area. That being said, I refer you to my recent post to Cody.
Member Since: March 7, 2007 Posts: 558 Comments: 20000
Quoting alfabob:

Ok
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Quoting JrWeathermanFL:


Whats at 80W?


Lots of "Warm Water"

Taco :o)
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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.

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