Dr. Jeff Masters' WunderBlog

The Northeast Heatwave

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

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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301. wunderkidcayman 2:45 PM GMT on July 07, 2010
Here you go Funkadelic 00z GFS 18Z GFS 12Z GFS Member Since: June 13, 2009 Posts: 2 Comments: 5450

303. HurricaneSwirl 2:46 PM GMT on July 07, 2010
Quoting Dakster: 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. Thanks, that's probably the best explanation for it. Still strange tho considering that even though our NWS in Peachtree City is used to it, I don't think the NWS in Wakefield(?) is. Member Since: July 7, 2008 Posts: 2 Comments: 3237

304. Squid28 2:46 PM GMT on July 07, 2010
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) Local news reported last night, that they have now found tarballs at Matagorda beach as well. Just a quick hop over to Corpus and they will have covered all of the Texas coast as well. Member Since: May 23, 2006 Posts: 0 Comments: 343

305. mrsalagranny 2:47 PM GMT on July 07, 2010
Oh im being nice.I really mean no harm.I thought it was funny i have a mrgranny Member Since: June 6, 2010 Posts: 0 Comments: 732

306. Orcasystems 2:47 PM GMT on July 07, 2010
Ok, last one for a bit.. some of us have to pretend we are getting ready for work :) AOI AOI AOI AOI TS BUSTED FORECAST ALIBI Member Since: October 1, 2007 Posts: 77 Comments: 26077

307. nrtiwlnvragn 2:47 PM GMT on July 07, 2010
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. Depends on area of the coutry, max & min heat index, plus local health care partners. Link pages 3,4 and 5 Member Since: September 23, 2005 Posts: 11 Comments: 8937

308. txsweetpea 2:47 PM GMT on July 07, 2010
Quoting mrsalagranny: Thank you Sweetpea.I dont know who this mralagranny is.He is disquising himself as my husband,And my husband doesnt een get on this blog,LOL!!!!!!I needed a good laugh today. Yea my husband thinks I am obsessed with Hurricane season...and he never gets on here ..dont worry about whoever it is.. it will come out! Keep the prayer going and have faith! Member Since: June 7, 2010 Posts: 0 Comments: 546

310. txsweetpea 2:49 PM GMT on July 07, 2010
BBL...have errands to run. Member Since: June 7, 2010 Posts: 0 Comments: 546

311. mrsalagranny 2:49 PM GMT on July 07, 2010
My husband does too.He said I should study weather.And when i say something about the weather he calls me meterologist Brenda.LOL Member Since: June 6, 2010 Posts: 0 Comments: 732

312. watchingnva 2:50 PM GMT on July 07, 2010
Quoting HurricaneSwirl: Yeah your place is probably gonna be the hotspot today, even places like Phoenix, AZ probably won't match your high heat index wise, because their heat is so dry. I dunno what's up with your local NWS, all I can find are Air Quality Alerts. i dont understand how they can have severe air quality alerts and ozone alerts, and all this...but not put an advisory out...lol...maybe bc weve already had like 7-10 days of 100+ days here this summer that they think we are use to it:))...and my family and i were the smart ones who when to the beach on monday...and the river in downtown richmond yesterday...never again going to belle isle on a 100+ days...the boulders were scorching...you could fry an egg on them if you wanted to, and there are freaking river rocks with rapids around them...lol...too hot...dry heat i dont usually have a problem with...but 103-105 with a dewpoint higher than 65...no thank you...lol Member Since: September 7, 2005 Posts: 3 Comments: 1310

314. Kristina40 2:50 PM GMT on July 07, 2010
Quoting mrsalagranny: My husband does too.He said I should study weather.And when i say something about the weather he calls me meterologist Brenda.LOL My husband is beginning to feel that way as well. He is somewhat fascinated with weather himself although he doesn't go so far as to dig into the whys and hows. He likes to photograph it. Member Since: June 27, 2010 Posts: 0 Comments: 681

315. watchingnva 2:51 PM GMT on July 07, 2010
Quoting mobilebayal: Watchingnva, I have no idea. I just copied and posted the definition I found. lol...oh i know mobile...lol:P...i was just saying, ya gotta wonder how they think sometimes...lol Member Since: September 7, 2005 Posts: 3 Comments: 1310

316. Squid28 2:52 PM GMT on July 07, 2010
Quoting Patrap: 1 Dr. Peppa,,and one box-o-raisinet's please. TYVM. I prefer a glass of milk and a Charleston Chew myself.... Member Since: May 23, 2006 Posts: 0 Comments: 343

317. mrsalagranny 2:52 PM GMT on July 07, 2010
LOL Kristina.I bet he has some good pics. Member Since: June 6, 2010 Posts: 0 Comments: 732

318. PensacolaDoug 2:52 PM GMT on July 07, 2010
Just another troll. Member Since: July 25, 2006 Posts: 0 Comments: 4828

319. AussieStorm 2:52 PM GMT on July 07, 2010
Quoting Orcasystems: Ok, last one for a bit.. some of us have to pretend we are getting ready for work :) Oh, sux to be you, I am not long home from work.,,,, Have a good day at work. Don't work to hard, or just make it look like your working hard but really are not. Member Since: September 30, 2007 Posts: 5 Comments: 13351

320. Orcasystems 2:54 PM GMT on July 07, 2010
Quoting AussieStorm: Oh, sux to be you, I am not long home from work.,,,, Have a good day at work. Don't work to hard, or just make it look like your working hard but really are not. I hired the daughter to take over... so I am there...sort of...maybe...but not really. Hmm sort of like be before she started :) Member Since: October 1, 2007 Posts: 77 Comments: 26077

321. watchingnva 2:55 PM GMT on July 07, 2010
Quoting HurricaneSwirl: Thanks, that's probably the best explanation for it. Still strange tho considering that even though our NWS in Peachtree City is used to it, I don't think the NWS in Wakefield(?) is. not at all...lol....we do have hot summers...but usually maybe a few days around 100...and 90's the rest of the time...not day after day of 103 ...this week is going to be our second stretch of these high of temps...lol Member Since: September 7, 2005 Posts: 3 Comments: 1310

323. mrsalagranny 2:56 PM GMT on July 07, 2010
Did someone say something about another wave coming to the Carribean? Member Since: June 6, 2010 Posts: 0 Comments: 732

324. Kristina40 2:57 PM GMT on July 07, 2010
Quoting mrsalagranny: LOL Kristina.I bet he has some good pics. My avatar is one he took with his cell phone. Member Since: June 27, 2010 Posts: 0 Comments: 681

325. mrsalagranny 2:58 PM GMT on July 07, 2010
That is beautiful. Member Since: June 6, 2010 Posts: 0 Comments: 732

326. TxGrandma 3:00 PM GMT on July 07, 2010
Quoting LoneStarWeather: 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. My personal favorite, that they were stuck on a ship and dropped in Galveston. I know they have to protect the tourist industry as best they can, but these tarballs have been confirmed to come from the Deepwater Horizon, and Galveston just isn't that far from Louisiana. I have serious doubts that those danged things came from a ship bringing oil to a refinery, not when they've been washing ashore for 2 days now. It breaks my heart, but I can't bring myself to swim in those waters anymore, and I feel like I'd better go dolphin watching while there are still any to watch. Member Since: August 29, 2008 Posts: 0 Comments: 29

328. CybrTeddy 3:03 PM GMT on July 07, 2010
Daily update: 96L Highly disorganized, CV storm possible, La Nina arrives 7/7/10 Member Since: July 8, 2005 Posts: 253 Comments: 20259

331. angiest 3:04 PM GMT on July 07, 2010
From NWS Houston/Galveston, containing one of the biggest "duh" statements I have seen... A deep tropical air mass is in the process of filtering back into the region. As this occurs...conditions will be somewhat favorable for short lived funnel clouds for the next few days. Although the vast majority of these features do not make it all the way to the ground to produce tornados it is not completely out of the question. Should you see any funnels begin to descend close to the ground...take shelter because they can produce damage. We will continue to monitor radar and issue warnings if necessary. They are going to monitor radar? Really? Shocking, I tell you! Member Since: August 26, 2006 Posts: 16 Comments: 4766

332. HurricaneSwirl 3:05 PM GMT on July 07, 2010
Quoting watchingnva: i dont understand how they can have severe air quality alerts and ozone alerts, and all this...but not put an advisory out...lol...maybe bc weve already had like 7-10 days of 100+ days here this summer that they think we are use to it:))...and my family and i were the smart ones who when to the beach on monday...and the river in downtown richmond yesterday...never again going to belle isle on a 100+ days...the boulders were scorching...you could fry an egg on them if you wanted to, and there are freaking river rocks with rapids around them...lol...too hot...dry heat i dont usually have a problem with...but 103-105 with a dewpoint higher than 65...no thank you...lol Lol I don't understand it either. But you better be used to it today as this is gonna be the worst of it for you guys. Then it's our turn come thursday :(, although we're still only forecast to hit 101-102, which is still a nice couple of degrees cooler than what you're getting today so im fine :) Man and on the topic of scorching boulders I remember going to Jekyll island last year during a heat wave that brought heat indexes up to around 120 degrees.. I literally burnt my feet on the sand, and I thought the water would cool me down. It didn't :( Member Since: July 7, 2008 Posts: 2 Comments: 3237

333. HurricaneSwirl 3:06 PM GMT on July 07, 2010
Quoting watchingnva: not at all...lol....we do have hot summers...but usually maybe a few days around 100...and 90's the rest of the time...not day after day of 103 ...this week is going to be our second stretch of these high of temps...lol Yeah I know your used to the 90's but 105 with 70 dewpoint I don't think anyplace along the East Coast is used to that! haha Member Since: July 7, 2008 Posts: 2 Comments: 3237

334. wunderkidcayman 3:06 PM GMT on July 07, 2010
yes waves waves and waves will be coming into the Caribbean it is a normal thing its not like every will develop if it did happen we wolud have between 80-100 storms per year but yeah more wave are comming into the Caribbean Member Since: June 13, 2009 Posts: 2 Comments: 5450

335. CybrTeddy 3:07 PM GMT on July 07, 2010
Quoting jasoniscoolman2010x: wow Trough split combined with a tropical wave. Possibility of a sub-tropical low exists. Member Since: July 8, 2005 Posts: 253 Comments: 20259

336. AussieStorm 3:09 PM GMT on July 07, 2010
Well all, I am off to bed. But I will leave you with this.... Currently at Homebush, Sydney, Australia. Temperature 47.1°F falling Dew Point 39.9°F falling Feels Like 47.1°F Relative Humidity 76% Wind Wind Gusts - Pressure - Fire Danger - Rain since 9am/last hr 0.0mm / ______________________________________________________________________________________________ Alice shivers through coldest day on record Alice Springs has had its coldest day on record, shivering through single digit temperatures yesterday. Sally Cutter from the weather bureau says Alice Springs reached a maximum of just 6.4 degrees celsius yesterday afternoon(43.5F). "That makes it the coldest on record for Alice Springs and those records are fairly old," she said. "I think it was 1948 was the coldest July day and 1966 was the previous coldest day on record." The Northern Territory's previous coldest day was 5.9 degrees celsius(42.6F) , recorded in Yulara in 1997. The wet conditions are continuing in Alice Springs, with the airport recording almost 70 millimetres(2.7inches) of rain since the start of the month. The average rainfall for July in Alice Springs is 14 millimetres(0.5inches). © ABC 2010 Member Since: September 30, 2007 Posts: 5 Comments: 13351

337. atmoaggie 3:10 PM GMT on July 07, 2010
Want to never be overly hot again? Had a job one summer at Texas A&M tending to cotton fields. All work by hand, no machines. Weeks of ~100 F and just under 70F dewpoints and out in it 10 hours a day. Try it and no amount of hot will actually bother you ever again... Member Since: August 16, 2007 Posts: 6 Comments: 12461

338. hurricanehanna 3:12 PM GMT on July 07, 2010
Quoting Squid28: I prefer a glass of milk and a Charleston Chew myself.... my hubby and I went to the movies with our 9 year old. matinee mind ya - $28 to sit and watch. Popcorn and drink extra. Geezum Member Since: September 5, 2007 Posts: 0 Comments: 3214

339. angiest 3:14 PM GMT on July 07, 2010
Quoting atmoaggie: Want to never be overly hot again? Had a job one summer at Texas A&M tending to cotton fields. All work by hand, no machines. Weeks of ~100 F and just under 70F dewpoints and out in it 10 hours a day. Try it and no amount of hot will actually bother you ever again... In blue jeans and a long sleeve button up shirt, right? But of course, the clothes were probably cotton, not synthetic. Member Since: August 26, 2006 Posts: 16 Comments: 4766

340. OneDay 3:18 PM GMT on July 07, 2010
Hey atmo...I did A/c work laying ducts in new home construction in central TX for a summer. That'll put hair on your chest, let me tell you. 100-102 outside everyday and I was in the attic. Member Since: July 13, 2005 Posts: 35 Comments: 929

341. Inyo 3:19 PM GMT on July 07, 2010
yeah heat advisories are in theory based on how the heat affects people. True, it is often this hot in Florida and Death Valley and such. However, I live in Vermont and am currently in Pittsburgh - in both places a lot of people do not have AC at all and in Pittsburgh it is also really difficult to find a place to sleep outside. So it is pretty much miserable here... it would be hard to find anyone on the Gulf Coast without AC and anyone without it hopefully at least has an outdoor patio with a bug net to sleep on. Kind of like flash flood warnings - 2 inches of rain in a few hours won't necessarily cause a flash flood in Georgia and no amount of rain can cause one in most of Florida since it is flat, but an inch of rain or less in a short period of time can cause flash flooding in the Southwest due to lack of vegetation, rock outcroppings, steepness, etc etc. Also a forecast of 1 inch of snow in January will trigger 'winter weather headlines' in Sacramento, California, because it is extremely rare to get snow there. If we had those warnings in Vermont every time we had 1 inch of snow they would be in effect for months and totally meaningless. It doesn't make sense to have nationwide standards for these things. Member Since: September 3, 2002 Posts: 42 Comments: 765

342. OneDay 3:20 PM GMT on July 07, 2010
then again, I've never had to shovel snow in a blizzard either.... Member Since: July 13, 2005 Posts: 35 Comments: 929

343. NRAamy 3:20 PM GMT on July 07, 2010
cold and rainy here..... Member Since: January 24, 2007 Posts: 315 Comments: 31937

344. help4u 3:20 PM GMT on July 07, 2010
Jim williams said at this time in 2005 we already had 4 named storms,with dry air and cooler tchp i would say 2005 is safe to keep it's record. Member Since: September 18, 2006 Posts: 0 Comments: 1071

345. ElConando 3:20 PM GMT on July 07, 2010
Wade and Bosh to Miami!!!! Erm I mean hows 96L? Member Since: September 6, 2009 Posts: 2 Comments: 3703

346. Dakster 3:21 PM GMT on July 07, 2010
Quoting AussieStorm: Well all, I am off to bed. But I will leave you with this.... Currently at Homebush, Sydney, Australia. Temperature 47.1°F falling Dew Point 39.9°F falling Feels Like 47.1°F Relative Humidity 76% Wind Wind Gusts - Pressure - Fire Danger - Rain since 9am/last hr 0.0mm / ______________________________________________________________________________________________ Alice shivers through coldest day on record Alice Springs has had its coldest day on record, shivering through single digit temperatures yesterday. Sally Cutter from the weather bureau says Alice Springs reached a maximum of just 6.4 degrees celsius yesterday afternoon(43.5F). "That makes it the coldest on record for Alice Springs and those records are fairly old," she said. "I think it was 1948 was the coldest July day and 1966 was the previous coldest day on record." The Northern Territory's previous coldest day was 5.9 degrees celsius(42.6F) , recorded in Yulara in 1997. The wet conditions are continuing in Alice Springs, with the airport recording almost 70 millimetres(2.7inches) of rain since the start of the month. The average rainfall for July in Alice Springs is 14 millimetres(0.5inches). © ABC 2010 You are not winning any sympathy's here... I'd take 40's over 100's any day. Member Since: March 10, 2006 Posts: 0 Comments: 4938

347. NRAamy 3:21 PM GMT on July 07, 2010
DestinJeff.....I love it!!!!! :) Member Since: January 24, 2007 Posts: 315 Comments: 31937

348. tropicfreak 3:22 PM GMT on July 07, 2010
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. You're right about Richmond, all the local forecasts in my area say at least 103! Heat indexs won't be a big factor because its not going to be humid. Member Since: September 2, 2006 Posts: 110 Comments: 6566

350. tropicfreak 3:25 PM GMT on July 07, 2010
Quoting watchingnva: 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 Morning watch!! Today will be our last day in the triple digits! Wohoo!! Member Since: September 2, 2006 Posts: 110 Comments: 6566

351. help4u 3:25 PM GMT on July 07, 2010
You know the tropics are dead when the talk is anything but tropics.Good day to go christmas shopping.lol Member Since: September 18, 2006 Posts: 0 Comments: 1071

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