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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2106. Patrap
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Quoting muddertracker:
There really isn't much going on at the surface with 90l...will that change soon?


Was wondering the same thing.
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Quoting jeffs713:

Actually.. its pretty close to that. My wife and I drove to NOLA and back, and as soon as you pass beltway 8 on I-10 going east out of houston, it starts getting more and more green. by the time you're solidly in Chambers county, its green all over.


Yea, I drove to Lake Charles and noticed the exact thing 2 weeks ago
Member Since: July 14, 2008 Posts: 1 Comments: 9630
2103. Patrap
Elvis has left da blog
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There really isn't much going on at the surface with 90l...will that change soon?
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Quoting atmoaggie:
I think that's a bit of a reach...

We might get 10 inches from a average local TC event and 35 inches for the year.

I wouldn't say that our current set up is due to a tropical wave or cyclone, but a number of places got 10 inches in the last 2 weeks and the whole area (SE LA), by eyeball averaging, about 5 inches.
I don't know anything about 10inches of rain here just north of the Woodlands. We are still begging for rain. Got about half an inch yesterday but the area is still in very bad shape. Houston is looking to Lake Conroe for water now.
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2100. Levi32
Gotta head to work now. Later all.
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2099. ncstorm
Days 1-5 rain totals

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Quoting barbados246:
Levi you need to come to Barbados enjoy this lovely sunshine, a couple Banks Beers and you would be fine. you would not even remember the heat :)
We had discussed the upper air obs from Barbados last week.

I found out that the hydrogen generator (for inflating the weather balloons, giving buoyancy) was not functioning. Supposedly will be fixed soon.
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2097. Patrap
POD wars?
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Quoting Levi32:


That got a laugh out of me lol.



But now, you're what, a CAT V hurricane? LOL
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Quoting atmoaggie:
On the topic of drought/flood, we are getting close to 600% of normal rainfall for the last 2 weeks (with more expected).

In Texas, in the width of one county, they go from 300% of normal to 5% of normal, in places. Very green to totally brown in 30 minutes on the highway, I'd imagine.


Actually.. its pretty close to that. My wife and I drove to NOLA and back, and as soon as you pass beltway 8 on I-10 going east out of houston, it starts getting more and more green. by the time you're solidly in Chambers county, its green all over.
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Quoting Levi32:


Nope. I would love to go sometime and experience the weather (namely thunderstorms). The only thing I dread is the heat.


People adapt. I went from the Panhandle of Florida to North Dakota (colder than Anchorage) and survived. First year was rough, but got acclimated to the point that when I visited here one winter I thought I was going to die in the 70 degree heat wave. Cold front then came through and I was in shorts in 50 degree weather. :)
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.
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WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT TUE 26 JULY 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 27/1100Z TO 28/1100Z JULY 2011
TCPOD NUMBER.....11-056

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (NEAR TIP OF YUCATAN)
FLIGHT ONE -- TEAL 70
A. 27/1800Z
B. AFXXX 01DDA INVEST
C. 27/1530Z
D. 22.0N 87.0W
E. 27/1730Z TO 27/2130Z
F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: BEGIN 6-HRLY FIXES
AT 28/1200Z NEAR 23.0N 91.5W IF SYSTEM DEVELOPS.
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Quoting louisianaboy444:


Yes, and the Gulf coast which gets the majority of its rain a year from TCs and TWs has been void of anything the past few years....everything going into Mexico or elsewhere..i never seen anything like it before...surely not like it was when i was growing up i dont know whats going on
I think that's a bit of a reach...

We might get 10 inches from an average local TC event and 35 inches for the year.

I wouldn't say that our current set up is due to a tropical wave or cyclone, but a number of places got 10 inches in the last 2 weeks and the whole area (SE LA), by eyeball averaging, about 5 inches.
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2090. Patrap
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2088. Levi32
Quoting BobinTampa:
Good to see we're working on the projected path and intensity of Levi's career.

j/k. Look forward to the day when we can all say we knew Levi (in and Internetty sort of way) when he was just an invest.



That got a laugh out of me lol.

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Quoting Levi32:


Nope. I would love to go sometime and experience the weather (namely thunderstorms). The only thing I dread is the heat.
Levi you need to come to Barbados enjoy this lovely sunshine, a couple Banks Beers and you would be fine. you would not even remember the heat :)
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2086. Patrap
Updated: 4:05 am CDT on July 26, 2011
Flash Flood Watch in effect for New Orleans until 7 PM CDT this evening...


Area forecast discussion
National Weather Service New Orleans la
332 am CDT Tuesday Jul 26 2011


Discussion...
the main concern for this forecast package is the potential for
localized heavy rainfall again today and perhaps tomorrow and the
resulting flash flood threat. A middle level weak short wave trough
or weakness over the southeast Continental U.S. Will continue to plague the
Gulf Coast region for the next two or three days. This feature
..along with a tropical airmass in place across the region with
precipitable water values well in excess of two inches...will be
conducive for widespread showers and scattered thunderstorms with
locally heavy rainfall amounts. Some areas have seen several
inches of rain over the past week or so...in some cases over
ten inches...and additional rainfall on saturated or nearly
saturated ground could result in flooding issues. As a result...a
Flash Flood Watch will be issued for today for the entire forecast
with a general one to two inches of rain possible...although
localized rainfall amounts of three to four inches will certainly be
possible in a few areas. This watch may have to be extended or
reissued for Wednesday as the threat for localized heavy rainfall
amounts will likely continue. Rain chances will begin to decrease
at the end of the week and especially over the weekend as the
short wave trough weakens and ridging aloft builds over the Gulf
region and somewhat drier air works into the area. A tropical wave
over the northwest Caribbean is forecast to move west across the
Gulf during the week. At this time it appears that this feature
will stay south of the coast and have minimal impact on the
forecast area. 11

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Good to see we're working on the projected path and intensity of Levi's career.

j/k. Look forward to the day when we can all say we knew Levi (in and Internetty sort of way) when he was just an invest.

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2084. Levi32
Presumably due to invest 90L, GOES-13 has gone into rapid-scan mode, and will now deliver 8 images per hour.

High-res Visible loop of 90L
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Quoting MrstormX:
I'm pretty sure Texans will take any TC at this point, even if it is a cane.


Yes, and the Gulf coast which gets the majority of its rain a year from TCs and TWs has been void of anything the past few years....everything going into Mexico or elsewhere..i never seen anything like it before...surely not like it was when i was growing up i dont know whats going on
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On the topic of drought/flood, we are getting close to 600% of normal rainfall for the last 2 weeks (with more expected).

In Texas, in the width of one county, they go from 300% of normal to 5% of normal, in places. Very green to totally brown in 30 minutes on the highway, I'd imagine.

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2081. Patrap
2km Storm Relative IR Imagery with BD Enhancement Curve




2km Storm Relative IR Imagery with BD Enhancement Curve

The same infrared imagery shown in the earth relative framework is displayed in a storm relative framework, with a 2km resolution and enhanced with the "BD Curve" which is useful for directly inferring intensity via the Dvorak Enhanced IR (EIR) technique. Scaling is provided by two lightly hatched circles around the center. The two circles have radii of 1 and 2 degrees latitude, respectively.
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Quoting Minnemike:
my tropical cyclone knowledge is fairly minimal in comparison to some here, so what are the factors against 90L, that seem to convince the NHC to 'low ball' it? is it just model guidance? it looks to me like it has a real potential to become trouble, or maybe that's just flare ups from all the TCHP it's over... seems to be organizing, gaining vorticity, and perhaps stalling a little.

good question! i would like to know this as well
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2079. Levi32
Quoting muddertracker:

If it stays south is it more likely to develop? Less sheer?


It doesn't appear here that track will make a huge amount of difference in its environmental conditions, but farther north may be slightly more favorable, as the system could slip a little bit more beneath the wings of the southern U.S. 200mb ridge, perhaps lightening the upper winds slightly.
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2078. Patrap
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I'm pretty sure Texans will take any TC at this point, even if it is a cane.
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AL, 90, 2011072612, 200N, 830W, 25, 1010, DB
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Quoting Levi32:


Nope. I would love to go sometime and experience the weather (namely thunderstorms). The only thing I dread is the heat.
I sometimes really miss the snow storms i only have seen one so far in my life and i'm 27 already .
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Quoting Levi32:


BAM suite still thinks northern Mexico, but the few GFS ensemble members that develop it think Texas. It'll be a close call either way, probably not that far away from the border based on when that high is supposed to slip eastward. A trough digging into the Pacific northwest right now should push it far enough east to allow 90L to gain some latitude before coming ashore.

I hadn't seen the ensemble members yet, thank you for adding that. The GFS has done decently well so far this year (at least locally with our rare rain events, and the tropical stuff so far in the ATL), so I'll put more faith (and desperate hope) in it for now.

Of course, at the moment, any model projections are barely better than a shot in the dark, since the models don't have a good grip on the center.
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Quoting Levi32:


BAM suite still thinks northern Mexico, but the few GFS ensemble members that develop it think Texas. It'll be a close call either way, probably not that far away from the border based on when that high is supposed to slip eastward. A trough digging into the Pacific northwest right now should push it far enough east to allow 90L to gain some latitude before coming ashore.


If it stays south is it more likely to develop? Less sheer?
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Quoting RitaEvac:


That's our hope! bring rain, but this needs to be watched, this one could spin up fast


Yeah but the models look pointed at you no where again...Mexico...this year is playing just like the last few this must be absolutely frustrating for Texas along with TC bring rain its the balance of the planet
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Just woke up, seems that 90l is looking good this morning. I think there is a good chance it enters the gulf as a TD.
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2069. Levi32
Quoting belizeit:
Levi have you ever been to the Tropics?


Nope. I would love to go sometime and experience the weather (namely thunderstorms). The only thing I dread is the heat.
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2068. Levi32
Quoting jeffs713:

for sure. beautiful country up in Boulder.

Has anyone seen updated model runs for steering of 90L? (ie: will the high move east enough at the right time to allow a weak-ish system to come ashore on the TX coast?)


BAM suite still thinks northern Mexico, but the few GFS ensemble members that develop it think Texas. It'll be a close call either way, probably not that far away from the border based on when that high is supposed to slip eastward. A trough digging into the Pacific northwest right now should push it far enough east to allow 90L to gain some latitude before coming ashore.

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2067. Patrap
Multiplatform Satellite Surface Wind Analysis





Multi-Platform Tropical Cyclone Surface Wind Analysis

Currently, this product combines information from five data sources to create a mid-level (near 700 hPa) wind analysis using a variational approach described in Knaff and DeMaria (2006). The resulting mid-level winds are then adjusted to the surface applying a very simple single column approach. Over the ocean an adjustment factor is applied, which is a function of radius from the center ranging from 0.9 to 0.7, and the winds are turned 20 degrees toward low pressure. Over land, the oceanic winds are reduced by an additional 20% and turned an additional 20 degrees toward low pressure.

The five datasets currently used are the ASCAT scatterometer, which is adjusted upward to 700 hPa in the same manner as the surface winds are adjusted downward, feature track winds in the mid-levels from the operational satellite centers, 2-d flight-level winds estimated from infrared imagery (see Mueller et al 2006 ) and 2-d winds created from Advanced Microwave Sounding Unit (AMSU)- derived height fields and solving the non-linear balance equations as described in Bessho et al (2006). Past analyses also made use of the QuickSCAT scatterometer (i.e., prior to November 2009), but this satellite is no longer producing observations of surface vector winds.

Each of the input data are shown in subpanels following the analysis (i.e., storm-relative). Shown are AMSU winds, Cloud-drift/IR/WV winds, IR-proxy winds and Scatterometer winds; QuikSCAT, when available for past analyses (BLUE) and ASCAT (RED). All input data in these panels has been reduced to a 10-m land or oceanic exposure depending on the location (i.e., non-surface data has been reduced to a 10-m exposure).

How good are the wind estimates? Here is the verification based upon 2007 data . These statistics were based on 1) H*Wind data when available and 2) best track wind radii estimates from NHC. In interpreting the wind radii verification it is important to not that the zero wind radii are included in the verification, which both skews and inflates the MAE verification statistics. Note however detection is improved over climatology provided by Knaff et al. (2007).
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Quoting CybrTeddy:
Invest 90L a possible threat to develop 7/26/11

Enjoy!

Thanks for the Texas love, CT. We definitely need some rain mojo.
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You guys might not like it (and Levi might wish we would stop arranging his career), but I could envision him either with The Fleet Weather Center in San Diego or
The Naval Maritime Forecast Center in Pearl Harbor. Both support the JTWC.

More tropical activity in their purview, and better local weather, than NHC/Miami.
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It will be interesting to see exactly where the Surface Low is and where it starts. That will be huge in what 90L becomes!
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Quoting Chucktown:


The Weather Channel is what it is. Its now owned by a major network and driven by advertisement. Granted its quality has dropped significantly since it first came on, but so has a lot of mainstream America. I have a few friends that work there, it is run just like any other business. Cut costs where you can and make as much as you can with minimal staffing.


I concur with you 100%, quality has been slipping. I noticed it got worse after NBC purchased it, better as an independent entity.
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Quoting Levi32:
It's true...I would melt. 75 degrees F at 15% humidity in the height of summer here is too much for me. Miami gets the same temp at 70% humidity in the middle of winter lol.
Levi have you ever been to the Tropics?
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Quoting jeffs713:

for sure. beautiful country up in Boulder.

Has anyone seen updated model runs for steering of 90L? (ie: will the high move east enough at the right time to allow a weak-ish system to come ashore on the TX coast?)


That's our hope! bring rain, but this needs to be watched, this one could spin up fast
Member Since: July 14, 2008 Posts: 1 Comments: 9630
2060. Patrap
The GOES-13 Floater is active on the RAMMB Page


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Invest 90L a possible threat to develop 7/26/11

Enjoy!
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Quoting atmoaggie:
I think that entirely depends on when/where it pops, relative to landmasses.
(Assuming it pops at all...I *think* it will, but is certainly speculative.)


You don't see a good surface Low either yet as i do. Its getting close, but just not to the Surface yet.
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Quoting Abacosurf:


No question.

But wait...Levi's tropical tidbit stories....ahhh. forget it. Too restricting.


The Weather Channel is what it is. Its now owned by a major network and driven by advertisement. Granted its quality has dropped significantly since it first came on, but so has a lot of mainstream America. I have a few friends that work there, it is run just like any other business. Cut costs where you can and make as much as you can with minimal staffing.
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Quoting Levi32:
It's true...I would melt. 75 degrees F at 15% humidity in the height of summer here is too much for me. Miami gets the same temp at 70% humidity in the middle of winter lol.


Except for that one day in Feb when it gets to 70. We have two seasons here: blazin' hot and a little toasty.
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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.