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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WTNT01 KNGU 072000
SUBJ/TROPICAL CYCLONE FORMATION ALERT 072000Z JUL 10//
RMKS/1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 23.8N 93.6W TO 26.1N 98.8W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNING AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 20 TO 25 KNOTS. METSAT
IMAGERY AT 071930Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 23.8N 93.6W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 13
KNOTS.
2. REMARKS: A BROAD AREA OF LOW PRESSURE LOCATED JUST WEST OF THE
YUCATAN PENINSULA TRACKS WEST-NORTHWEST TOWARDS THE NORTHEAST COAST
OF MEXICO. THE LATEST METSAT IMAGERY INDICATES INCREASED CONVECTION,
WHICH IS INDICATIVE OF STRENGTHENING. INCREASED SEA SURFACE TEMPERATURES
IN THE REGION AND LIGHT UPPER LEVEL WIND SHEAR WILL PROVIDE FAVORABLE
CONDITIONS FOR TROPICAL CYCLONE DEVELOPMENT.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 082000Z.//
Member Since: Posts: Comments:
Quoting Tazmanian:

when dos this site update next???


ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/
At around 8:30 PM EDT or 5:30 PM PDT.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1035. USSINS
Folks, we're not talking about giving these systems a name if they don't meet the TS criteria. But these systems with all their tropical aptitude, and especially when they are closer to shore, imo, really should be expedited towards a TD status, whether conditions meet the letter of the criteria or not.

Anything that creates better awareness, preparedness for public safety is helpful. Waiting until the last minute to even declare a TD is just being intentionally omissive and treading closely towards malfeasance.
Member Since: Posts: Comments:
Quoting Hurricanes101:


wow way to take his statement out of context; he is right though

a weak system can kill thousands in Mexico while likely would not do that in the US, it isnt like he is wishing a CAT 5 on a major city; lighten up

It wasn't taken out of context. I know what he meant but wishing any kind of storm on your own country is asinine at best. Wish it to go back to sea but don't wish it here.
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Naked swirl center near 27N... 70W.
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when dos this site update next???


ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/
Member Since: May 21, 2006 Posts: 5091 Comments: 115436
Latest GFS still showing the cape Verde season starting around July 18 2 possible storms. Been consistent at least, just something to look for in the next two weeks.

Link
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WOW

there is no warning image on the navy site so where are you getting this
Member Since: Posts: Comments:
Quoting MississippiWx:


Ha, thanks. I try. I guess this is my 4th year on WU, and I've learned a lot in that time because of people like Drak, Storm, Ike, Pat, and Levi. I'm leaving some people out, I know, but I know so much more about tropics now than I did when I first started.
I came in September of last year and learned a lot from all of them. Hope to see you here for many more years...
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting LoneStarWeather:

You are a serious idiot. I'm sorry but wishing a storm to hit your own country over another is twisted. You don't think thousands of people could be killed here? What's wrong with you?


wow way to take his statement out of context; he is right though

a weak system can kill thousands in Mexico while likely would not do that in the US, it isnt like he is wishing a CAT 5 on a major city; lighten up
Member Since: March 10, 2010 Posts: 1 Comments: 7874
1025. CJC111
All these . posts. What's the point? (Sorry, couldn't resist)
Member Since: Posts: Comments:
Quoting IKE:


I've got 52 year-old teeth....oatmeal cookies are easier on them.

I like chocolate chip cookies if their soft:)


yeah, soft ones are the best. Right out of the oven...
Member Since: Posts: Comments:
1023. IKE
Quoting TexasHurricane:


aaawww coke. My favorite drink. I however prefer chocolate chip cookies. :)


I've got 52 year-old teeth....oatmeal cookies are easier on them.

I like chocolate chip cookies if their soft:)
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting StormW:


However, I have to commend Stacy Stewart for doing what he did, cause had it stalled, it most likely would have become classified.


True. It was very close. I think if it would have had one more day over water, it would have been a no brainer.
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1020. IKE
Convection waning a little on 96L.

Just reporting what I see.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:
*Oatmeal cookies and iced Coke this afternoon. Carry on.*


aaawww coke. My favorite drink. I however prefer chocolate chip cookies. :)
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i say 96L is now a TD or a weak TS
Member Since: May 21, 2006 Posts: 5091 Comments: 115436
Quoting IKE:
*Oatmeal cookies and iced Coke this afternoon. Carry on.*


you sure it wasn't iced oatmeal cookies and coke? lol

Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting MiamiHurricanes09:
Oh I never knew it detached from the frontal boundary. But it also lacked deep convection. Either way the past is gone and it never was classified.


atcf took off the "TD" classification it had for 95L in that one advisory
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting MiamiHurricanes09:
Lol, naaa your much more intelligent that many on here so I'm sure you've gotten many more things right.


Ha, thanks. I try. I guess this is my 4th year on WU, and I've learned a lot in that time because of people like Drak, Storm, Ike, Pat, and Levi. I'm leaving some people out, I know, but I know so much more about tropics now than I did when I first started.
Member Since: Posts: Comments:
Quoting IKE:
*Oatmeal cookies and iced Coke this afternoon. Carry on.*
I think you might want some pepto bismol with that one...
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1012. NRAamy
kelley...even I don't go that far....
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1011. Patrap
Yup,

..nice lil after tropical day here.

Got da weed wacking done and now Im going to Polish my toes.

Clear of course.

C-yas tomorrow
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Quoting StormW:


Well, prior to landfall, it detached from the front...however per NHC criteria, it lacked deep organized convection for the time requirement, radar representation showed an open SW side, and visible satellite showed the convection it did have, was to the SE of the center.
Oh I never knew it detached from the frontal boundary. But it also lacked deep convection. Either way the past is gone and it never was classified.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1009. Squid28
Who knows, you could be right, or the buoy could have been vandalized, taken a rogue wave or just had the effects of continious saltwater exposure working it over for too long.

A few year ago, I followed a buoy around that broke loose just to see how long it drifted and where before being recaptured. I think it blew around for like 3 or 4 months just reporting data back the whole time. kinda cool to watch actually, if you ever see some of the really big ones in person, they are impressive to what they stand up to out at sea.
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1008. IKE
*Oatmeal cookies and iced Coke this afternoon. Carry on.*
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting StormW:


Well, prior to landfall, it detached from the front...however per NHC criteria, it lacked deep organized convection for the time requirement, radar representation showed an open SW side, and visible satellite showed the convection it did have, was to the SE of the center.


Once again, you were correct with 95L. Props to you! Glad the NHC stayed consistent and didn't classify it.
Member Since: Posts: Comments:
Quoting Hurricanes101:


was it ever tagged an invest? lol


it was labeled invest "sninty seven L".
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting Patrap:
Seems da Boyz are alil touchy after they blew 95L

LOL


.."Hooper drives da boat!"..
I think we're going to need a bigger gulf of mexico." Afternoon, Patrap. Ya'll drying out in LA yet?
Member Since: August 16, 2007 Posts: 1 Comments: 2351
Quoting kelley9:


.

Got you all beat. I actually have a period. :P OK. Maybe that's taking it too far.


Kelley, that's just wrong, okay?
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Quoting MississippiWx:


Seems like you and me had this nailed yesterday. This is the first time I've checked on 96L today and I figured it would develop from the circulation over the Yucatan. I got it right, for once!
Lol, naaa your much more intelligent that many on here so I'm sure you've gotten many more things right.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
Guess you didn't see the ASCAT or surface analysis.


Seems like you and me had this nailed yesterday. This is the first time I've checked on 96L today and I figured it would develop from the circulation over the Yucatan. I got it right, for once!
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Quoting ElConando:
The only thing that has been blown recently is my nose.


was it ever tagged an invest? lol
Member Since: March 10, 2010 Posts: 1 Comments: 7874
What the analog dogs dont ever see..its not whatcha call it,..its what it does.

Ciao..

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The only thing that has been blown recently is my nose.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting Patrap:
Seems da Boyz are alil touchy after they blew 95L

LOL


.."Hooper drives da boat!"..
It was attached to a frontal boundary, thus non-tropical. So we didn't really blow it, it just didn't meet the requirements to be called a tropical or subtropical cyclone.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting StormW:


Well, nobody blew 95l...it didn't meet the criteria...period.


agreed 100%
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Seems its time for a cool breeze..


Anchors aweigh,.....to Henry's




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Good afternoon wx undergrounders!
UUL and a tropical southerly component slowly getting together SSW of Bermuda?

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Seems da Boyz are alil touchy after they blew 95L

LOL


.."Hooper drives da boat!"..
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Quoting StormW:
They don't issue TCFA for open waves.



thats telling him lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115436
SSD floater overlays are the least accurate depiction of the actual surface map drawn up by the NHC, and update quite late most of the time. Surface maps show 96L is a closed low that is on its way to becoming a tropical depression.
Member Since: November 24, 2005 Posts: 635 Comments: 26698
Quoting Patrap:
The 96L is a Open wave..

Click FRONTS and MSLP

Gulf Of Mexico - Rainbow Loop
Guess you didn't see the ASCAT or surface analysis.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting jeffs713:

Thats not what I meant. Stronger systems tend to come from the S or SE, since they are usually longer-track systems. Generally, the longer the track, the more likely it is to strike perpendicular to the coast.
Interesting point.
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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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