The Northeast Heatwave

By: Dr. Jeff Masters , 9:08 AM GMT on July 07, 2010

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Hi, Dr. Rob Carver, filling in for Jeff while he's on vacation.

The most significant weather event in the US on July 6, 2010 didn't show up on any radar. The geostationary satellites didn't see it in their constant watch over the Earth's atmosphere. Instead, the tale of this event was told by the thermometers, because the heatwave in the Northeast was the most significant event for July 6, and it will likely be the most important weather story for July 7.

The heat wave covers Pennsylvania to Maine, but Tuesday's worst was centered over New York City. All six of the stations used by the New York NWS office for climate reports (Central Park, La Guardia, JFK, Islip, Bridgeport, and Newark) set or tied the daily high temperature record. Newark and Central Park both reached 103 degrees F.

How unusual is this heat wave?
Figures 1 and 2 show how warm the highs and lows are compared to 30 year averages. Unless you were at the Great Lakes, the Midwest and Northeast have highs well above normal, with 10-15+ degree F differences over the coastal cities of the Northeast. Using my gridded temperature data, the low for New York City was 6 degrees F above normal, which should happen 30% of the time (1.1 standard deviations away from normal). The high was roughly 20 degrees above normal, which should happen only 0.29% of the time (3.04 standard deviations away from normal). This is an unusually strong heat wave.

Why it's hot
Basically, it's because there is "the Bull of a high pressure ridge [over the NE US]" to quote the Mount Holly NWS office forecast discussion. The large ridge of high pressure is forcing air to slowly descend across the Northeast, preventing clouds from forming. Without no clouds and plenty of daylight, the Sun heats the ground which then heats the air.

When will it cool down?
That's an excellent question. A trough of low pressure off the coast will bring onshore winds to the Tri-State area and MA by Thursday, so they should cool down a bit. The southern part of the heat wave, DC and Philadelphia, will have to wait for a cold front to arrive from the Great Lakes sometime Saturday to get relief.

Population affected
As Figure 3 shows, heat advisories covered most of the urban areas of the northeastern US. By my calculations, over 32 million people were under a heat advisory. Different offices have different guidelines for heat advisories. The NWS office responsible for New York issues a heat advisory if the heat index will be above 95 deg. F for two or more days or if the index will be above 100 deg. F for any length of time.


Fig.1 Plot of the difference between maximum temperature (the high for the day) and average maximum temperature in degrees F for July 6.


Fig.2 Plot of the difference between minimum temperature (the low for the day) and average minimum temperature in degrees F for July 6.


Fig.3 Plot of the active heat advisories across the northeastern US for July 6.

Heatwave impacts
The predominant impact from heat waves is increased mortality. CDC estimates that over 8,000 people died during heat waves from 1979 to 2003. That's more than all of the deaths due to lightning, flooding, tornadoes, hurricanes, and earthquakes. The elderly, sick, poor, and very young face the worst of the effects of the heat. Wikipedia has an interesting article describing the Chicago Heat Wave of 1995, a modern heat wave with a large number of fatalities due to the heat.

Heatwave coping strategies
The Centers for Disease Control have some tips for dealing with the heat. In summary, drink plenty of water, spend time in air-conditioned buildings, and wear light-colored clothing.

Is this heat wave due to global warming?
Ah, the $64,000 question. In the absence of detailed analysis, it's hard to specify the exact cause for this heat wave, from a meteorological or climatological view point. However, events like this are consistent with research showing that heat waves are more likely with
global warming
. I like the metaphor of loaded dice, global warming is not specifically responsible for any heat wave, but it will make them happen more often.

Tropics
My thinking on Invest 96L is unchanged from this blog entry. In summary, I believe that 96L has a <50 % chance becoming a tropical cyclone before it makes landfall. If it does so, it will likely be near the coast when that happens. In any event though, the winds and waves it generates will likely disrupt oil spill recovery efforts. Also, I would expect a broad area of showers and 20+ mph winds will affect the Gulf coast somewhere from south Texas to Louisiana.

Next update
I'll have an update this afternoon to talk about the tropics.

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Quoting StormW:


Well, right now, until I get updated steering for tonight, there are 2 possible scenarios...it continues SSW, and crosses into FL., or it continues SSW, stalls, does a semi-cyclonic loop, and heads back out to sea.
Hopefully not a loop thing like Jeanne in 04. Thanks
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Quoting extreme236:


Agreed. Probably similar intensity to what TS Erin was (One good analogy Reed used for this).
That's a really good example as far as intensity and track goes.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting extreme236:


No I was talking about 96L and then the "Reed Low" lol
Hokay. Since 95L went inland, I wasn't aware there was much of anything else, besides 96L, to look at...but I have been fairly busy, lately.

And, here I go to busy-land, L8R, y'all.
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The CPC forecast in the green circle labled as "4" shows a high chance for rainfall in these areas, suggesting the potential for some type of disturbances (whether or not they are or become tropical cyclones) to be around.
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Quoting PtownBryan:


I think that is a pretty good guess. And it starts raining harder as I say that LOL.


Yep -- she's going to be a rain machine. Not Alex's caliber, but more than I think most people are expecting.
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Quoting txalwaysprepared:


Yep. We rode the west side of the eye for a good bit. And the back side of the storm was much worse. I never expected that!!


Me either. I know that at 3 or 4 am I wanted to get a little rest...as I lay in the recliner...I sit up and say..this ain't normal! lol. No sleep for me until about 8 or 9 that morning...I was so tired I slept in the heat and didn't care how much I sweated!
Member Since: July 5, 2010 Posts: 0 Comments: 170
Quoting StormW:


Well, right now, until I get updated steering for tonight, there are 2 possible scenarios...it continues SSW, and crosses into FL., or it continues SSW, stalls, does a semi-cyclonic loop, and heads back out to sea.


The wave in the Bahamas may cross into Florida?
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting StormChaser81:
Most of all NOAA crew where military and now work for NOAA, which falls under federal. Atleast thats what I've been told could be wrong.
Yep. I know of one that went from AF HH to NOAA just a year or 2 ago.
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Quoting MiamiHurricanes09:
Agree. Short-term focus is on 96L, once this system is gone we focus on the non-tropical low by the Bahamas. From what I'm seeing 96L will become Bonnie, but will likely not exceed the 40mph threshold. Then again, it doesn't have much time over water so we aren't going to see a strong system.


Agreed. Probably similar intensity to what TS Erin was (One good analogy Reed used for this).
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Quoting btwntx08:
i think we will get a weak 40-45 ts out of this


I think that is a pretty good guess. And it starts raining harder as I say that LOL.
Member Since: July 5, 2010 Posts: 0 Comments: 170
Quoting PtownBryan:


Ike did go just east of downtown. I know, I live south of downtown in a city called Pearland...the eye went to our east and we never had calm winds except before Ike started and when he decided to leave like 10 hours later! lol. Crazy how the second half of the storm was worse than the first part. If Ike would have hit my county(brazoria) instead of Glaveston county, Galveston would have been in far worse shape and it was bad enough just taking the direct hit, less dirty part!


Yep. We rode the west side of the eye for a good bit. And the back side of the storm was much worse. I never expected that!!
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Quoting atmoaggie:
??? whiskey tango foxtrot? I think you just described the same system twice...


No I was talking about 96L and then the "Reed Low" lol
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Quoting extreme236:
I'd rather keep an eye on 96L which has a very good chance to develop into a cyclone in the short term rather than a weak non-tropical low that most likely will not develop in the short couple day window it has.
Agree. Short-term focus is on 96L, once this system is gone we focus on the non-tropical low by the Bahamas. From what I'm seeing 96L will become Bonnie, but will likely not exceed the 40mph threshold. Then again, it doesn't have much time over water so we aren't going to see a strong system.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting angiest:


No, last week was Alex. 95L was a couple of days ago .

True. My bad. They're coming thick and fast this year. But please, no more Katrina's, Rita's, or Ike's--except the blogger, of course!
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Next week's most likely focus will be in the area shaded red on the map. Perhaps if this CV storm starts to begin to take shape late in the week that could be of interest as well.

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Quoting extreme236:
I'd rather keep an eye on 96L which has a very good chance to develop into a cyclone in the short term rather than a weak non-tropical low that most likely will not develop in the short couple day window it has.
??? whiskey tango foxtrot? I think you just described the same system twice...
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96L is looking better on satellite.. it feels as if it's beginning to concentrate the convection on a spin
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Hurricane hunter missions:

In the United States, the Air Force, Navy, and NOAA units have all participated in this mission.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
Quoting kelley9:


Agreed. Been a "watcher" for many years, (I'm asperger's and kinda anti-social) but finally decided to join the blogging masses, so I kinda already know who to avoid, who's alright and who's talking out of their... um, behind. Ya know?
Yep, I do...
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Quoting louisianaweatherguy:


yeah Rita hit the LA/TX border... Ike pretty hit Houston head on, right?


Ike did go just east of downtown. I know, I live south of downtown in a city called Pearland...the eye went to our east and we never had calm winds except before Ike started and when he decided to leave like 10 hours later! lol. Crazy how the second half of the storm was worse than the first part. If Ike would have hit my county(brazoria) instead of Glaveston county, Galveston would have been in far worse shape and it was bad enough just taking the direct hit, less dirty part!
Member Since: July 5, 2010 Posts: 0 Comments: 170
Lots of low level convergence associated with 96L as well
Member Since: October 28, 2006 Posts: 57 Comments: 30841
I'd rather keep an eye on 96L which has a very good chance to develop into a cyclone in the short term rather than a weak non-tropical low that most likely will not develop in the short couple day window it has.
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Quoting AllBoardedUp:
Thanks, and that ain't good for us. Looks no end in sight, whether it develops, or not!


I got 2 inches so far today -- that's on top of the 10 last week from Alex.
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Quoting OracleDeAtlantis:
I've never seen so many [snip] over 95L not being classified as tropical.
??? Was the tone there really necessary?

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Quoting OracleDeAtlantis:
I've never seen so many crybaby wannabe whiners over 95L not being classified as tropical.
Hey! We resent that! We're not whiners! LOL
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Quoting atmoaggie:
Even the NOAA crews? (pretty sure they are not)


Most of all NOAA crew where military and now work for NOAA, which falls under federal. Atleast thats what I've been told could be wrong.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
Quoting btwntx08:

really looks good to me lol


I say we send in a boat. Got plenty of 'em out that way these days, ya know? ;)
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Quoting Hurricanes101:


It can be both, he said no TD tonight

Last I checked, none of us said that either lol
He was continuously saying that it isn't going to develop and that everyone is hyping it. Now he changed his mind. Oh well.

CIMSS 18:00 UTC 850mb vorticity product.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
For those curious as to what the track and intensity of this storm means to the people of the Rio Grande: the current river forecast peak for Laredo is ~38 feet. If the river crests six feet lower than that:

THE LOWEST BUSINESSES NEAR THE RIVER FLOOD IN DOWNTOWN LAREDO. RUNOFF DOWN FROM CHACON AND ZACATE CREEKS ADD TO THE RIO GRANDE RIVER BACKFLOW...AND CAN FLOOD HOMES ALONG THESE CREEKS. STREETS AND BRIDGES ARE FLOODED AND ARE EXTREMELY DANGEROUS TO TRAFFIC


If the river crests six feet higher than that:

MASSIVE RESIDENTIAL AND COMMERCIAL FLOODING OCCURS. NEAR THE RIVER...AND ALONG CHACON AND ZACATE CREEKS...FLOODING CAN BE LIFE THREATENING...AS THE RIO GRANDE RIVER BACKS THEM UP. THE SEWAGE PLANT IS UNDER SEVERAL FEET OF WATER. THE INTERNATIONAL BRIDGE FLOOR FLOOR FLOODS...AND LIVESTOCK ARE CUT OFF AND POTENTIALLY DROWNED IN THE FLOOD PLAIN...ABOVE EAGLE PASS TO FALCON RESERVOIR


So what this storm does is very relevant, even if it never becomes super-windy.
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Quoting IKE:


96L.
Thanks, and that ain't good for us. Looks no end in sight, whether it develops, or not!
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Quoting lhwhelk:

96L. 95L is what hit us last week, bringing 5" of rain on Wed, Thurs, & Fri to Lake Jackson. So far today, just 1" here.


No, last week was Alex. 95L was a couple of days ago (though I am not convinced all the moisture has left).
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Quoting StormW:


The Atlantic Ocean. (Just kidding) an upper low that has entrained energy from a tropical wave. We are waiting to see if it can organize at the surface.
and----if it did organize, what direction would it be heading, other than my direction?
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Quoting NttyGrtty:
Nah, none taken. When I get offended, I just add the offender to my ignore list...LOL. Life's too short to type angry...


Agreed. Been a "watcher" for many years, (I'm asperger's and kinda anti-social) but finally decided to join the blogging masses, so I kinda already know who to avoid, who's alright and who's talking out of their... um, behind. Ya know?
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Quoting StormW:


Oh, no...not NOAA, they work for the Dept. of Commerce...I was talking about the 53rd Recon Air Wing.
Regardless, I'd wager that the required personnel are not dependent on tasked missions to have a salary. Probably paid the same, regardless, and should be. (Would you want the part-timer worried about his real job being the one analyzing onboard radar?)
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Quoting BenInHouTX:


Thanks for the response. I may have to check it out.

I guess if we ever want to have a gathering of all the Houston area Wunderground folks, that could be a cool place to meet up.


Pharr, TX. here.......it would be fun to meet and put faces with the blog handles. OK, back to lurking.
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Quoting MiamiHurricanes09:
So which one is it?


Whomever is on at the time.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting reedzone:
I'm out, I will check on 96L and the NON-TROPICAL Low when I get back, take it easy guys, nothing too organized, no red on the next TWO, no TD tonight... Look at reality.


Red on the next TWO is only a 10% increase. I find it incredibly hard to believe it would not increase at least 10% more. Probably more like 70-80% in my opinion.
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Quoting AllBoardedUp:
Is all this rain in SE Texas coming from remnants of 95L, or 96L? Or neither?

96L. 95L is what hit us last week, bringing 5" of rain on Wed, Thurs, & Fri to Lake Jackson. So far today, just 1" here.
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Quoting MiamiHurricanes09:
So which one is it?


It can be both, he said no TD tonight

Last I checked, none of us said that either lol
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting angiest:


That would have put landfall at roughly the same area as the 1900 storm, and as it was the Sea Wall was topped by the combination of surge proper and waves on top. That would have also created a major disaster on the Ship Channel, and would have put downtown Houston and the west side of Houston in the eastern eyewall. Did you see houstonhidefromthewind.org? It was created by HCOEM to inform people of what types of wind to expect (from Ike). The website is still there with the data from advisory 49A. Where-ever landfall was expected at that time, my zip code was still going to receive sustained winds in excess of hurricane force. On an earlier advisory (around the time I made the decision to leave and not trust my tract home), we were a lot closer to the forecast track of the eye and we were going to have sustained winds of almost 100mph. The 1900 storm was our best analogue at that time.
I can't imagine a Katrina type of storm surge hitting south of Galveston/Houston area! I know Katrina was probably the exception and not the rule, but it still possible. It's a matter of when, not it it'll happen. But of course, the "when" might not happen in our life times.
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Quoting reedzone:
I'm out, I will check on 96L and the NON-TROPICAL Low when I get back, take it easy guys, nothing too organized, no red on the next TWO, no TD tonight... Look at reality.
Quoting reedzone:


Thats what I'm thinking, TD right before landfall, maybe a weak TS at best. I don't see anything stronger then that. It's moving at a good clip. Back later, great video update btw.
So which one is it?
Member Since: September 2, 2009 Posts: 130 Comments: 21194
837. IKE
Quoting AllBoardedUp:
Is all this rain in SE Texas coming from remnants of 95L, or 96L? Or neither?


96L.
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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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