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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Hope everyone is ok who were near the earthquake.
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Quoting HaboobsRsweet:

yea 95L barely looked like a thunderstorm. It was a said excuse for an invest. I think 96L could easily make TD status tonight but I just dont think it has the time to get to Bonnie...it will be close and could go either way. def leaning towards it having near zero chance for hurricane.


oh yea I think all of us think a hurricane is very very slim

TD, or 50mph TS at best, keep in mind with the way the Texas coastline is shaped, if it comes in a bit further north it may allow 96L another 6-12 hours over water
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I'm wondering if it's the same fault as the easter quake. And I certainly hope that's not a foreshock. Looks like it's going to be a long night.
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1534. Drakoen
AL, 96, 2010070800, , BEST, 0, 235N, 938W, 30, 1005,
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1533. centex
I can assume we will see a model shift to right and it may get out of the coolest Alex waters.
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Quoting StormW:


Oh please! Give it a rest. 95L didn't have half the structure of this...totally different critter anyway...95 L was from a baroclinic process, this is purely tropical.

yea 95L barely looked like a thunderstorm. It was a said excuse for an invest. I think 96L could easily make TD status tonight but I just dont think it has the time to get to Bonnie...it will be close and could go either way. def leaning towards it having near zero chance for hurricane.
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1531. Jynni99
Quoting zoomiami:


That's ridiculous - tons of people don't have AC - I grew up in a house without ac and managed to survive.


LOL I have 2...
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Quoting WatchingThisOne:
Prelim mag 5.9

* 22 km (13 miles) NNW (332°) from Borrego Springs, CA
* 23 km (14 miles) SE (131°) from Anza, CA
* 33 km (20 miles) NE (52°) from Lake Henshaw, CA
* 45 km (28 miles) S (174°) from Palm Springs, CA
* 94 km (58 miles) NE (41°) from San Diego, CA


I'm watching the USGS site and see nothing other than a 2.7 for the L.A. area.

There was this - yesterday or very early today: MAP 5.4 2010/07/07 23:53:33 33.417 -116.483 11.7 SOUTHERN CALIFORNIA
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1528. USSINS
Quoting Drakoen:






Funny, Drak. Humor. WTG! LOL.

And, Ike, don't feel bad. I'm blind in one eye and can't see with the other either. ;)

But, imo, 96L should have already warranted TD status. I'm not saying TS by any means. But, a TD, yes.
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somehow, I knew this thing was gonna get going at the last minute.. I know u experts r probably thinking it doesnt have time to be a cane but I have this gut feeling it will be at least a category 1. from past canes what warrants mandatory evacuations ? man the clouds here in corpus christi looks ominous !!
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1526. SLU


80% chance


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Quoting Drakoen:





LOL poor horse
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Quoting TxMarc71:


How can you live anywhere in the contental U.S. and not have an A/C?? Thats suicide by ignorance in my opinion. I've lived all over the U.S. during my time in the Navy and I know for a fact that it gets hot enough in the East every year to demand an A/C plain and simple..

Seems like the headline should be .. "record number of heatwave residients have NO A/C"?

Its summer time in the USA... you need an A/C I dont care where u live unless its Alaska or Hawaii..

Fact stil remains.. record heat OR record cold here never makes national news nor should any other area getting a good taste of summer right now..



Our grandparents didnt have A/C either yet you and I still managed to somehow materialize..

Think about it...


That's ridiculous - tons of people don't have AC - I grew up in a house without ac and managed to survive.
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1523. Levi32
Quoting Drakoen:





LOL
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looks like a TD to me NOW.... so I would be surprised if it wasn't upgraded soon...

TD tonight 90% ... named TS tomorrow 70%..

Cat1 at landfall --- 20%
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Earthquake in California:

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Quoting StormW:


NW.


so is it still going to the Brownsville area?
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Quoting Drakoen:



LOL!!
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Wow... 80%!!
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Quoting HouGalv08:
Per the NWS forecast discussion issued at 15:13 this afternoon, I'd imagine so--"HOWEVER IT WAS IN-
TERESTING TO NOTE THAT MODELS ARE NOW KEEPING THESE ELEVATED RAIN
CHANCES IN FOR M0ST OF SE TX ON FRI. IT APPEARS THAT THE MOISTURE
FROM THAT WEAK TROPICAL WAVE WILL BE APPROACHING FROM THE S/SW AS
IT MOVES FURTHER INLAND."


Thats what I was wondering about. Does that mean they think the whole system will swing NE after landfall? I didn't notice any model but the 18z CMC showing this.
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NRA - funny how that happens - still a bit quesy. HEARD that one coming before it hit.
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80% Almost a TD... if it gets an update to TD before 2:00AM is there a consolation prize??
1320
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1512. Drakoen
Quoting StormW:


Oh please! Give it a rest. 95L didn't have half the structure of this...totally different critter anyway...95 L was from a baroclinic process, this is purely tropical.



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1511. KEEPEROFTHEGATE (Mod)
NMFC Norfolk Tropical Feed
Atlantic Tropical Cyclone Formation Alert (TCFA) 96L
By Maritime.CDO@navy.mil (NMFC CDO) from Naval Maritime Forecast Center Norfolk Virginia. Published on .

Issued: Wed 07 Jul 2010 20:00Z
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Click me!

Looks like the NHC lost their conservitive side,lol.
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1508. IKE
*Called in to my optometrist and made an appt.*

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1506. NRAamy
I'm good, Dak...just feel seasick...


:)
Member Since: January 24, 2007 Posts: 316 Comments: 31944
Quoting HurricaneSwirl:


I agree, it should have been red regardless, but it looks like this team is putting out higher percentages than we expect, just like some (kimberlain?) put out lower than we expect. Just something to throw out there!
LOL, yup.
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1504. KEEPEROFTHEGATE (Mod)
UNCLAS
MSGID/NMFC/OVLY2/0087/JUL
OVLY/TCFA/072000Z9/JUL/1OF1/TCFA AL9610/METOC
LINE/2//G/234800N7/0933600W1/260600N4/0984800W9
LINE/2//G/251200N0/0924800W3/221800N3/0943000W6
LINE/2//G/221800N3/0943000W6/243600N5/0994200W4
LINE/2//G/243600N5/0994200W4/273000N2/0980000W7
LINE/2//G/273000N2/0980000W7/251200N0/0924800W3
TEXT/20//G/211800N2/0961200W8/TCFA AL9610
TEXT/20//G/201800N1/0961200W8/VALID UNTIL 082100Z
TEXT/20//G/191800N9/0961200W8/WINDS: 20-25 KTS
TEXT/20//G/181800N8/0961200W8/MVG: WNW AT 13 KNOTS
ENDAT
BT
NNNN

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1502. Levi32
The dropsondes the recon plane has been dropping have confirmed a nice, closed, well-defined circulation at the surface, though they haven't gotten really close to the surface center yet to see how tight it is. The plane is up at the 640mb level and thus the winds being reported here are in the mid-levels. The mid-level center appears elongated based on these observations, which is expected since it's still trying to get stacked over the surface center to the north.

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Quoting Inactivity:
I think we will wake up to TD2,this will most likely become a TS with 50 mph winds.


Thats sounds about right.. based of the storms recent intensification
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1500. Levi32
Quoting duajones78413:
Levi, does this change your thoughts on the possibility of this thing becomine a cane?


Nope. It won't.
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Navy Tropical Cyclone Formation Alert
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Quoting MiamiHurricanes09:
Regardless of who wrote the TWO, "red" was expected by many. I also like Avila.


I agree, it should have been red regardless, but it looks like this team is putting out higher percentages than we expect, just like some (kimberlain?) put out lower than we expect. Just something to throw out there!
Member Since: July 7, 2008 Posts: 2 Comments: 3237
1497. NRAamy
I'm in Southern Calif., Orange County....the whole court rocked and rolled....
Member Since: January 24, 2007 Posts: 316 Comments: 31944
Quoting StormW:


Oh please! Give it a rest. 95L didn't have half the structure of this...totally different critter anyway...95 L was from a baroclinic process, this is pruely tropical.


Hi storm, is 96L moving WNW or NW?
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1495. Dakster
Quoting NRAamy:
here, Dak! here! SoCal!!!!


You seem to be ok since you can still blog... Is everything ok?
Member Since: March 10, 2006 Posts: 0 Comments: 9673
Quake downgraded to mag 5.4

Info on CA quake
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I think we will wake up to TD2,this will most likely become a TS with 50 mph winds.
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Quoting IKE:


And?


highly doubt 1 has anything to do with the other

if you actually look in depth at both systems you would see that in terms of tropical development, 96L is better organized than 95L was
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Maybe NHC is getting something like this in real time from the P3 3D Doppler Radar, This image is from this mornings mission.


Member Since: September 23, 2005 Posts: 13 Comments: 10458
Last time we had 80% on TWO was Alex.. we saw an upgrade at 5 pm.
Member Since: July 8, 2005 Posts: 259 Comments: 23012
Quoting HurricaneSwirl:


Yup! From now on we know that the "FORECASTER STEWART/CANGIALOSI" is the less conservative team IMO.
Regardless of who wrote the TWO, "red" was expected by many. I also like Avila.
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1487. IKE
Quoting Hurricanes101:


and??


And?
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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.