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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Weds. July 7th. Tropical Update w/ Video
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264: Do I see west winds in the southern recon pass?
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Quoting MahFL:
The two halfs of convection seem to be gradually trying to meet up.....like segments of an orange.


Look at the area on water vapor loop and see that odd dry slot..96L has had plenty of moisture in it's in environs but there is that dry slot...must of slept through a "dry air encounter"...
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Quoting aquak9:
MahFL- advanced skywarn spotter, ARIES...hmmm. we've probably met.

Oksana is braver than ever before, ya'll. Don't get sucked in.


Good call!!!
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Quoting HurricaneSwirl:


Repost. Maybe it's a dumb question but I'm curious :)


im just se of richmond, and the dewpoint has been creeping up overnight and are now in the mid 60s to low 70's...70 here at the house...and the dewpoint in places like albany are only a few degrees higher at 73-76...so, im fairly confused as well...according to weather.gov....albany is only getting up to 96-98 with heat index of 103-105...while its gonna be 103-105 here today with an index of 106-108...lol...ive always wondered what the criteria has been...lol
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Heat Advisory - Extreme heat index making it feel hot, typically between 105 °F to 115 °F (41 °C to 46 °C) for up to 3 hours during the day and at or above 80 °F (24 °C) at night for two consecutive nights. Specific criteria varies over different county warning areas.[26]

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MahFL- advanced skywarn spotter, ARIES...hmmm. we've probably met.

Oksana is braver than ever before, ya'll. Don't get sucked in.
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Quoting StormW:


Look harder.


It's hard to tell what this thing is doing. I see giant elongated vortices, I seen what I think are mid-level vortices, I see phantom vortices. Take your pick this A.M.
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Who are you?I have never seen you on here before.
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277. MahFL
Quoting aquak9:
repeat question-

MahFL- are you in Jacksonville?


13 miles SW of JAX.
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274. MahFL
Quoting StormW:


Go here to visible, put it in motion, and zoom in to near where I've posted.

NASA


Ok I see it now, but I also see a coc further SE, so I see two....
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repeat question-

MahFL- are you in Jacksonville?
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Storm.....thanks.
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Quoting HurricaneSwirl:


Repost. Maybe it's a dumb question but I'm curious :)


Not a dumb question. The only anser I can give is that heat advisories are up to the local NWS offices as Dr. Carver pointed out. I would think if you are in an area that routinely gets that hot - there wouldn't be an advisory.
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Quoting MahFL:


Maybe you need to look harder !

I am not saying your wrong though, could be multiple coc's of course....


You are seeing the different layers of circulation there...check the low cloud product and see the area Storm is discussing...then note the IR view on the Goes12.
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1 Dr. Peppa,,and one box-o-raisinet's please.

TYVM.
Member Since: July 3, 2005 Posts: 426 Comments: 128871
267. MahFL
The two halfs of convection seem to be gradually trying to meet up.....like segments of an orange.
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Quoting StormW:


No...just come in a little further north...the way it's looking, maybe even less chance of development...we'll have to see what happens next.


Less chance of development would be good :)

I feel like Texas has a target on her back this year
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Quoting StormW:


Look harder.


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Quoting tkeith:
And a secret not published yet: Tarballs found west of the I-10 bridge)

not surprised Atmo...it was inevitable. a few more days of east/southeast winds like we've had and they'll find 'em at Manchac...

I heard a report on the radio this morning that tarballs have been found in the surf off Galveston. They have mostly been cleaned up now and officials suspect that either they were dragged here unknowingly by freighters or washed this way by the "freakish currents" created by Alex.
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Quoting HurricaneSwirl:
I have a question about what warrants heat advisories, they seem awful inconsistent to me..

Albany, NY will likely get to 95 today, but it is going to humid enough to put the heat index between 101 and 104. They are under a heat advisory.

Richmond, VA will likely get to 101-104 today, but it is dry enough so that the heat index probably won't surpass 106 or 107. They are not under a heat advisory.

Macon, GA will likely get to 95-98 today, but it is humid enough that the dew point will likely push heat indexes to around 105. They are not under a heat advisory.

When I saw Richmond wasn't under a heat advisory, yet it was going to be 10 degrees warmer than places that were, I thought it would be a humidity thing. But if it was a humidity thing then us in Macon would be under one too, so it can't be that... Man I'm confused.


Repost. Maybe it's a dumb question but I'm curious :)
Member Since: July 7, 2008 Posts: 2 Comments: 3237
oksana??

you gotta be kidding me...
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260. MahFL
Quoting StormW:


Look harder.


Maybe you need to look harder !

I am not saying your wrong though, could be multiple coc's of course....
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Quoting MahFL:


I can't see that myself, it's further south, just offshore the Yucatan, which means if it develops it's going to be stonger and proberbly further south towards MX.


Vertical stacking of the circulation is not complete with surface, mid and upper lows not moving fully together yet. There is also an unusual dry slot in the center layers of the "storm"....interesting...Alex seemed to have a similar dry issue but then he was pulling in dry air from the west most of his life span...where did this dry air come from in 96L"
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Thank you so much Helovetotrack.And you are right all things are possibe.
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Storm... what would that mean.. obviously less time over water?
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Good morning StormW, MahFL, Ike, everyone else.
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And a secret not published yet: Tarballs found west of the I-10 bridge)

not surprised Atmo...it was inevitable. a few more days of east/southeast winds like we've had and they'll find 'em at Manchac...
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with God anythings possible granny I will pray that God will heal her
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It seems 96l has really gotten ill.It seems like you worked some magic afterall Storm.LOL!!!!!
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248. MahFL
Quoting StormW:
Visible satellite loop imagery indicates the center of 96L may be further north, and coincides with the ATCF site near 23.3N;93.3W


I can't see that myself, it's further south, just offshore the Yucatan, which means if it develops it's going to be stonger and proberbly further south towards MX.
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Quoting atmoaggie:

Word is that what they have actually found in Lake P is a little sheen and tar balls (that probably passing under the barricading).

Tough to imagine any big reason to leave major channels open. Almost completely pleasure craft going through there. No industry/commercial reason to leave the Rigolets open. There is no major port of any kind in the lake...

(And a secret not published yet: Tarballs found west of the I-10 bridge)



1600 tar balls picked up yesterday alone and thousands more visible along SE end of lake.
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Storm....if you are still online, would you please go back to my post at 184 and comment?
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Quoting mrsalagranny:
Good morning Storm.And good morning blog friends.I know this off topic,but I really need those of you who beleive in prayer to please pray for my mother.She got some really bad news yesterday from her doctor.I really appreciate it everyone.Please forgive me for going off topic.


Peace for you and prayers for her and all around her.
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Storm I want get banned for my comments will I?I hope not. I meant to do no harm.
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Quoting Neapolitan:


My feelings about hurricanes--and tornadoes, and earthquakes, and volcanic eruptions, and tsunamis, etc.--is similar to how I feel about major crashes at, say, the Indy 500*: I'd rather they not take place at all, but since they are a natural byproduct of the way things are set up, and since they are therefore going to occur no matter how much we may wish it were otherwise, I want to at least be there to see it happen. And judging from the amount of enthusiasm--and, for some, obvious salivating--that appears on this blog anytime something big is building in the tropics, I'm not alone in my thinking. :-)

(BTW: Among others, I was in David in '79, Andrew in '92, Charley and Ivan in '04, and both Katrina and Wilma in '05, so I'm not talking completely out of one of my non-mouth orofices.)

* - Yes, I'm aware I'm comparing natural phenomena with a manmade activity. But I think the comparison holds true anyway.

I don't think the comparison is too much of a reach. The scale is vastly different, but the feeling is similar. I was one of those who always wanted to go through a hurricane... until Ike. Yes, I was over 60 miles inland, but when you are laying down on the floor of your apartment, and feel the entire building swaying with the wind gusts.. yeah. Or when I look out, and see a sweet gum tree bent at a 90 degree angle from the winds... yeah. OR go out after the storm, and just standing on my patio, can count 7 cars crushed from tree branches, 10 trees down, and debris everywhere... yeah. I still have the occasional nightmare (almost 2 years later) about Ike, and every time I hear a chainsaw and smell freshly cut wood, I have a momentary flashback.

Those same kind of feelings (especially the nightmares and flashbacks) come with any kind of traumatic event, such as hurricanes, tornadoes, car crashes and airplane crashes.

As I have a tendency to say, "Its all fun and games until you get hurt".
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Thank you Storm,Sweetpea,Pensacoladoug,Kristina,Mobilebay,and to any I may have missed.I know we all serve a God who can heal her.
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Quoting aspectre:
aspectre "How is crude getting into LakePontchartrain? Storm waves upon high tide overtopping the coast? Or leaving Rigolets/etc open for boat traffic instead of blocking the passages?
120 tkeith "both... Oh, and the booms dont work either. I spent 2 years building the new Rigolets Bridge and the currents at the Rigolets are comparative to river currents. I've spent alot of time on Pontchatrain, it makes me physically ill to see this."

My experiences were the coastal areas west of NewOrleans. It tightens my gut to think about them getting slimed... and about what it must be doing to the people who made their living/lifestyle there (though I s'pose things have changed so much that the lifestyle in my memories is mostly a thing of the past).
But I was thinking in terms of totally blocking inflow: eg dredging LakePonchartrain and dumping the mud&shells&etc into the passages. Too strong a current?

I'd say yes, too strong a current...
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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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