Dr. Jeff Masters' WunderBlog

A heat wave recap; generally quiet tropics
Posted by: Dr. Jeff Masters, 04:45 PM GMT am 25. Juli 2011 +6
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
Categories: Hurricane Heat
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1651. scott39 05:33 AM GMT am 26. Juli 2011    
NHC-10%
Member Since: Juni 13, 2009 Posts: 0 Comments: 6207
1653. Slamguitar 05:34 AM GMT am 26. Juli 2011    
Can't believe I'm staying up this late for a wave, lol. It does seem to be sustaining a good amount of convection. I also don't see it hitting the Yucatan, more likely to skirt the western tip of Cuba or shoot the gap from the looks of it. 20% for the TWO, but I feel like they'll play it more conservative and give 90L a 10% in the next 48.
Member Since: Juli 2, 2011 Posts: 0 Comments: 1021
1654. Stormchaser2007 05:34 AM GMT am 26. Juli 2011    
Quoting muddertracker:
Orange at the next TWO? Could be...hmmmm...
Quoting KEEPEROFTHEGATE:
30 percent chance coming up


HOWERS AND THUNDERSTORMS ASSOCIATED WITH A TROPICAL WAVE OVER THE
NORTHWESTERN CARIBBEAN SEA HAVE INCREASED SLIGHTLY DURING THE PAST
SEVERAL HOURS. DEVELOPMENT...IF ANY...OF THIS SYSTEM IS EXPECTED
TO BE SLOW TO OCCUR AS IT MOVES TO THE WEST-NORTHWEST AT 10 TO 15
MPH. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
Member Since: Juni 9, 2007 Posts: 4 Comments: 15248
1656. scott39 05:35 AM GMT am 26. Juli 2011    
NHC doesnt like what they see in the GOM for developement.
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1657. muddertracker 05:35 AM GMT am 26. Juli 2011    
No love for 90l...I'm off...have a good evening everyone.
Member Since: August 16, 2007 Posts: 1 Comments: 2119
1658. traumaboyy 05:36 AM GMT am 26. Juli 2011    
Morning night shift!! Coffee is ready!!
Member Since: August 18, 2008 Posts: 0 Comments: 2176
1659. bigwes6844 05:37 AM GMT am 26. Juli 2011    
Quoting muddertracker:

It seems to be moving about 10/12 right now? (guess)?
true u right but the wind shear i saw on the front page of wunderground shows that the shear is decreasing by the day after wednesday. we shall see.
Member Since: Juli 25, 2010 Posts: 0 Comments: 1384
1660. AtHomeInTX 05:37 AM GMT am 26. Juli 2011    
FWIW CMC takes the 850 vort into South Texas. Not developed and faint. Looks like maybe some part of Texas will get this whatever it may be.

Member Since: August 24, 2010 Posts: 0 Comments: 3874
1661. HurricaneHunterJoe 05:38 AM GMT am 26. Juli 2011    
Quoting KoritheMan:


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.
Vertical Integrity WooooooooDoggggies I like that!
Member Since: September 18, 2010 Posts: 0 Comments: 2690
1663. bigwes6844 05:39 AM GMT am 26. Juli 2011    
Quoting scott39:
It is... The last 6 hours is the slowest it has moved...14.6mph
Yeah cuz at once it was moving at 20 mph. I saw definetly hardly no shear for thursday maybe 5-10knts the most.
Member Since: Juli 25, 2010 Posts: 0 Comments: 1384
1664. lazerpointernerd 05:40 AM GMT am 26. Juli 2011    
10%
Member Since: April 12, 2006 Posts: 0 Comments: 44
1667. stillwaiting 05:40 AM GMT am 26. Juli 2011    
20%
Member Since: Oktober 5, 2007 Posts: 20 Comments: 4970
1669. AtHomeInTX 05:41 AM GMT am 26. Juli 2011    
Quoting muddertracker:
No love for 90l...I'm off...have a good evening everyone.


The Rodney Dangerfield of the Atlantic basin! LOL. Night everyone. :) Don't be surprised if I show back up later. :)
Member Since: August 24, 2010 Posts: 0 Comments: 3874
1671. bigwes6844 05:42 AM GMT am 26. Juli 2011    
Quoting jasonweatherman2011:
That looks pretty impressive on the close up. I believe the NHC is really smoking on something. It should be 30% by the next advisory. HOPEFULLY!
Member Since: Juli 25, 2010 Posts: 0 Comments: 1384
1673. scott39 05:44 AM GMT am 26. Juli 2011    
I think the NHC sees more land interaction with W Cuba instead of moving in the open NW Caribbean and then into wind shear once it reaches the GOM. I still think it has a shot. Its all going to be about forward speed and the timing of wind shear.
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1674. HurricaneHunterJoe 05:44 AM GMT am 26. Juli 2011    
Quoting Patrap:
Multiplatform Satellite Surface Wind Analysis

Time of Latest Image: 201107260000
what exactly does this chart imply?
Member Since: September 18, 2010 Posts: 0 Comments: 2690
1675. AtHomeInTX 05:45 AM GMT am 26. Juli 2011    
Quoting traumaboyy:
Morning night shift!! Coffee is ready!!


Have a good night trauma. Hate to bail but I guess I oughta try for a couple hours. :)
Member Since: August 24, 2010 Posts: 0 Comments: 3874
1676. aspectre 05:45 AM GMT am 26. Juli 2011    
1622 scott39 "90L is heading WNW at 184 degrees."
1624 muddertracker "Might 'shoot the gap'."
1625 scott39 "Yea, I dont see it touching the Yucatan."
1627 muddertracker "Me either...if anything, I think it might brush Cuba...}
1629 scott39 "I see it going over the very tip of West Cuba before going over the Yucatan. Its already at 19.5N"

From its last reported center position of 19.2n79.8, a heading of 184degrees takes the center between Cancun and Cozumel to a QuintanaRoo landfall on the YucatanPeninsula.
Copy&paste 19.2n79.8w-cun, 19.2n79.8-czm, gcm into the GreatCircleMapper for more info
Member Since: August 21, 2007 Posts: 0 Comments: 4846
1679. bigwes6844 05:47 AM GMT am 26. Juli 2011    
Quoting scott39:
I think the NHC sees more land interaction with W Cuba instead of moving in the open NW Caribbean and then into wind shear once it reaches the GOM. I still think it has a shot. Its all going to be about forward speed and the timing of wind shear.
exactly!
Member Since: Juli 25, 2010 Posts: 0 Comments: 1384
1681. bigwes6844 05:55 AM GMT am 26. Juli 2011    
Quoting alfabob:
And I believe it will shoot the gap, at the very least being on the edge of Cuban coastline; not going to inhibit it much though. Has been traveling W/WNW for a while now.
I just saw the model intensity not too long ago and it showed the SHIPS model having it as a 75 mph storm. Could that be true?
Member Since: Juli 25, 2010 Posts: 0 Comments: 1384
1682. HurricaneHunterJoe 05:56 AM GMT am 26. Juli 2011    
Quoting JrWeathermanFL:
Who thinks 90L will form?
Who thinks not?
I have been on the side of development since the beginning of 90L. Always thought it would take a few days for it to get going,but not his long. I still see it topping out as a moderate Tropical Storm, with landfall from S Texas to the LA border.....JMI !
Member Since: September 18, 2010 Posts: 0 Comments: 2690
1683. Stormchaser2007 05:58 AM GMT am 26. Juli 2011    
RGEM (Regional GGEM/CMC) develops 90L.

48 hours down to 999mbs

Member Since: Juni 9, 2007 Posts: 4 Comments: 15248
1684. scott39 05:59 AM GMT am 26. Juli 2011    
Quoting aspectre:
1622 scott39 "90L is heading WNW at 184 degrees."
1624 muddertracker "Might 'shoot the gap'."
1625 scott39 "Yea, I dont see it touching the Yucatan."
1627 muddertracker "Me either...if anything, I think it might brush Cuba...}
1629 scott39 "I see it going over the very tip of West Cuba before going over the Yucatan. Its already at 19.5N"

From its last reported center position of 19.2n79.8, 184degrees takes the center between Cancun and Cozumel to a QuintanaRoo landfall on the YucatanPeninsula.
Copy&paste 19.2n79.8w-cun, 19.2n79.8-czm, gcm into the GreatCircleMapper for more info
Your right, If 90L stays at exactly 184 degrees and doesnt change any... it will go where you pointed out. Mine is just a guess based on how often a wave can fluctuate in direction, and how crazy 90L has been.
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1686. scott39 06:03 AM GMT am 26. Juli 2011    
Looks like 90L maybe starting to take advantage of some Dmax...right at the center.
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1687. scott39 06:03 AM GMT am 26. Juli 2011    
NHC Please put a floater on 90L.
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1689. scott39 06:06 AM GMT am 26. Juli 2011    
Quoting alfabob:

Something even better Link
Thanks Saved
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1690. OracleDeAtlantis 06:10 AM GMT am 26. Juli 2011    
As requested ...
Member Since: August 27, 2009 Posts: 0 Comments: 288
1691. stillwaiting 06:14 AM GMT am 26. Juli 2011    
The spin on Cuban radar is in the mid level
Member Since: Oktober 5, 2007 Posts: 20 Comments: 4970
1692. scott39 06:16 AM GMT am 26. Juli 2011    
I think 90L is slowing down even more
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1694. aspectre 06:30 AM GMT am 26. Juli 2011    
aspectre "From its last reported center position of 19.2n79.8, 184degrees takes the center between Cancun and Cozumel to a QuintanaRoo landfall on the YucatanPeninsula."
1684 scott39 "You're right. If 90L stays at exactly 184 degrees and doesnt change any... it will go where you pointed out.
Mine is just a guess based on how often a wave can fluctuate in direction, and how crazy 90L has been.
"

Closer to an estimate than a guess. 90L's path over the most recently reported 18hours has shown a slight curvature evermore northward.
Just wanted folks to know where 184degrees was pointing.

Speaking of which, new ATCF numbers are overdue.
Member Since: August 21, 2007 Posts: 0 Comments: 4846
1696. TampaSpin 06:33 AM GMT am 26. Juli 2011    


WOW! Vorticity has improved a great deal the last 3 hours!




But, still no Convergence! Gotta have the Convergence before 90L is a player!
Member Since: September 2, 2007 Posts: 175 Comments: 19747
1698. OracleDeAtlantis 06:41 AM GMT am 26. Juli 2011    
Quoting TampaSpin:


WOW! Vorticity has improved a great deal the last 3 hours!




But, still no Convergence! Gotta have the Convergence before 90L is a player!
It's called being behind the curve .... A LOT.

This thing looked like a skater hitting the ice, only it's not ice.
Member Since: August 27, 2009 Posts: 0 Comments: 288
1701. OracleDeAtlantis 06:48 AM GMT am 26. Juli 2011    
Hard to go to sleep watching one like this, because it's moving so FAST. It's by far the fastest development we've seen since last year.

It just comes screaming out of the gate.
Member Since: August 27, 2009 Posts: 0 Comments: 288

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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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