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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I’m not going to give a percentage, but I think they will raise 96L to code red., just to play it safe since they cancelled recon. And speaking of recon, won’t 96 pretty much be close to making landfall by the time they get out there tomorrow?
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1135. USSINS
It's funny, really, to me. Now, we're teetering on percentages for a TD. Just call it a TD and put out TD alerts and create some general awareness ahead of time. Is the NHC gonna bat percentage balls around to within a few miles of shore?

I'm sorry, that's a complete lack of judgment and blatant disregard for public safety, imo.

I think I've made myself abundantly clear on the subject, so, much to many's liking probably, I'll shut up now and let those that enjoy getting technical get with it.
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Quoting TropicalAnalystwx13:


It depends on who does the Tropical Weather Outlook.
That might vary the percentage by 10% or so but doesn't give reason to not take 96L to red.
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Quoting CybrTeddy:
NHC will go with 60 or 70% IMO. Convection waning means very little.
Especially since they know that the SSTs left by Alex are effecting convection. Also, DMIN is having its effect on 96L.
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Quoting MiamiHurricanes09:
Still doesn't give enough reason to keep it the same. An anticyclone seems to be re-establishing itself aloft, and ASCAT showed a closed, but broad circulation. Also CIMSS vorticity products show that 96L is trying to align vertically through the 850mb-500mb levels. From what I see, the NHC should take 96L to a 70% chance at 8PM.


It depends on who does the Tropical Weather Outlook.
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NHC will go with 60 or 70% IMO. Convection waning means very little.
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1130. leo305
convection is waning due to DMIN, and some dry air, BUT the surface circulation seems to be consolidating and organzing with the convection, as the entire thing pulls to the NW, DMAX should really help it turn into a TD and potentially a TS before it hits land
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Quoting IKE:
I'll go with 50% on 96L the next TWO....convection is waning....

Still doesn't give enough reason to keep it the same. An anticyclone seems to be re-establishing itself aloft, and ASCAT showed a closed, but broad circulation. Also CIMSS vorticity products show that 96L is trying to align vertically through the 850mb-500mb levels. From what I see, the NHC should take 96L to a 70% chance at 8PM. Anyways it's probably the cold SSTs left by Alex and DMIN what is warming cloud tops.
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I been a pro subscriber for 5 years at least.
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Quoting IKE:
I'll go with 50% on 96L the next TWO....convection is waning....



Diurnal effects most likely taking effect here, along with cooler SSTs from Alex. Structurally, it's becoming better organized.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1125. Drakoen
Quoting Levi32:
Hey for those of you who love the ECMWF like me.....Accuweather Professional site is adding a host of new data to their ECMWF model page that you can't find anywhere else. The video on it is here.

I'm happy!!


Very nice. I might join for that sole purpose.
Member Since: October 28, 2006 Posts: 57 Comments: 30562
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1123. IKE
I'll go with 50% on 96L the next TWO....convection is waning....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
1122. IKE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
320 PM EDT WED JUL 7 2010

.SYNOPSIS...
-- Changed Discussion --
A WEAK AREA OF OFFSHORE LOW PRESSURE WILL APPROACH FROM THE EAST
TONIGHT AND THURSDAY THEN LIFT NORTH AND SLOWLY DISSIPATE FRIDAY.

A COLD FRONT WILL APPROACH FROM THE NORTHWEST SATURDAY THEN STALL
OVER THE REGION SUNDAY BEFORE DISSIPATING OR MOVING BACK NORTH AS
A WARM FRONT ON MONDAY. HIGH PRESSURE BUILDS OFF THE COAST ON
TUESDAY AND WEDNESDAY. ANOTHER COLD FRONT APPROACHES FROM THE WEST
LATE WEDNESDAY.
-- End Changed Discussion --

Member Since: June 9, 2005 Posts: 23 Comments: 37858
GFS degenerates the low after that though
Member Since: March 10, 2010 Posts: 1 Comments: 7816
42 hours, low off the NC coast

Member Since: March 10, 2010 Posts: 1 Comments: 7816
1119. Levi32
Quoting JamesGalloway:


Thanks. Does it only scan once a day?


2 passes a day.
Member Since: November 24, 2005 Posts: 635 Comments: 26652
Quoting Levi32:


Menu on top can take you to previous dates.

ASCAT


Thanks. Does it only scan once a day?
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1117. Levi32
Quoting JamesGalloway:
Hey guys, is there site that stores old ASCAT maps? I can only find the current one.


Menu on top can take you to previous dates.

ASCAT
Member Since: November 24, 2005 Posts: 635 Comments: 26652
Hey guys, is there site that stores old ASCAT maps? I can only find the current one.
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1115. Levi32
Alex's cool SST wake looks like it is playing a part in limiting 96L's convective development near the center:

Member Since: November 24, 2005 Posts: 635 Comments: 26652
1114. IKE
Operational GFS has 96L on land by hour 30...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
am going out like a bat an saying we may see 5 name storms in july with one un name storm
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1112. 7544
Quoting wunderkidcayman:
ok nice found it I refreshed the page

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.//

on other tropical notes we may get 97L 98L and 99L soon one being that non-tropical low near the E coast another being off the coast of Africa and the other that wave near 45W



agree and the blob east of fla is just sitting there gaining conv . this could get taggged latter 97l first imo

also now nootice the blow up just north of cuba and south of the bahamas getting convection there too . stay tuned
Member Since: May 6, 2007 Posts: 0 Comments: 6855
1111. USSINS
Quoting calder:
oh and USSINS, i wasn't trying to be inflammatory at all, I just believe differently, no disrespect intended


None taken. Feel the same way. We just disagree.
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Interesting, 18 hours we have possible TD 2 and the low off the NC coast looks to have intensified

Member Since: March 10, 2010 Posts: 1 Comments: 7816
1109. USSINS
Quoting calder:


The only headline that would be needed would be something along the lines of "Extremely dangerous rain event to occur in southern louisiana"


Yeah, buddy. I'm sure that'd get a "concerted" effort to create awareness. Headline? Who buys a paper anymore?
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1107. calder
oh and USSINS, i wasn't trying to be inflammatory at all, I just believe differently, no disrespect intended
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1106. Levi32
Quoting StormW:


Yeah...I saw that earlier and played around with the model...one of the best things they've done!


Indeed!

EDIT: Nevermind they do have the 12z run up...you just have to select it from the menu and ignore the "latest run is 00z July 7th" message.
Member Since: November 24, 2005 Posts: 635 Comments: 26652
Quoting Levi32:
Hey for those of you who love the ECMWF like me.....Accuweather Professional site is adding a host of new data to their ECMWF model page that you can't find anywhere else. The video on it is here.

I'm happy!!
Awesome! I purchased the Accuweather Professional a couple days ago, but have yet to use it. I'll make sure to check it out later this evening.
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Quoting Inyo:


how do you know he doesn't live in Mexico? Maybe he isn't wishing a storm on his own country. Anyway, it is true that storms often kill more people in Mexico. I hope no hurricanes hit any populated areas at all, myself.


and I bet if you asked that person they would much rather have a system go out to sea instead of hitting the US too. Just think there was way too much gray area there to warrant calling someone an idiot.

Either way, probably went on way longer than it should, going to look at some things on 96L
Member Since: March 10, 2010 Posts: 1 Comments: 7816
1103. calder
Quoting USSINS:


Yeah, and as much as I travel, I don't often even have time to watch TV, much less find TWC or even listen to the right radio station. But, if there were some general TD classification in these situations, a more concerted effort would be made within the media to create a better awareness - no matter which station one might be watching or listening.

What's the harm in the TD classification? Especially, when it could save lives?

Enough. It is what it is. Doesn't mean anyone has to agree with me, or that the NHC will take a different perspective. I just think a little different perspective and a bit less stringency and disrespect for the value of life and property could be helpful.

It's weather. It's not a finite science. It can be dangerous anytime, classified or not. But, certainly some general classification, imo, could be more helpful.


The only headline that would be needed would be something along the lines of "Extremely dangerous rain event to occur in southern louisiana"
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1101. Inyo
Quoting LoneStarWeather:

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.


how do you know he doesn't live in Mexico? Maybe he isn't wishing a storm on his own country. Anyway, it is true that storms often kill more people in Mexico. I hope no hurricanes hit any populated areas at all, myself.
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Quoting btwntx08:

barely


yeah, well, I did say a little... :)
Member Since: July 2, 2009 Posts: 0 Comments: 2811
ok nice found it I refreshed the page

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.//

on other tropical notes we may get 97L 98L and 99L soon one being that non-tropical low near the E coast another being off the coast of Africa and the other that wave near 45W
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1098. Levi32
Hey for those of you who love the ECMWF like me.....Accuweather Professional site is adding a host of new data to their ECMWF model page that you can't find anywhere else. The video on it is here.

I'm happy!!
Member Since: November 24, 2005 Posts: 635 Comments: 26652
FXUS64 KLCH 071751
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1251 PM CDT WED JUL 7 2010

UPDATE...ISSUED A FLOOD WATCH FOR LOWER SOUTHEAST TEXAS AS BANDS
OF HEAVY SHOWERS ARE MOVING IN TRAIN AND BACK BUILDING OVER THAT AREA.
AMOUNTS RANGING FROM 3 TO 5 INCHES ARE POSSIBLE THERE WITH SOME
LOCATIONS RECEIVING UP TO 10 INCHES TODAY. ALSO EXPECTING HEAVY
RAIN POISED NEAR THE COAST AND OFFSHORE OF ACADIANA TO MOVE INLAND
AND PRODUCE 1 TO 2 INCHES OF ADDITIONAL WITH ISOLATED AMOUNTS OF
UP TO 5 INCHES OVER AREAS WHICH ALREADY FLOODED YESTERDAY WHILE
DRAINAGE IN ESTUARY AREAS WILL BE COMPROMISED BY TIDES RUNNING 1
TO 2 FEET ABOVE NORMAL.
UPDATE...ADDED BACK IN TO REMARKS THE ONGOING FLOOD WATCH FOR
EASTERN PORTIONS OF ACADIANA. ALSO A MARINE WEATHER STATEMENT HAS
BEEN ISSUED FOR THE POSSIBILITY OF TROPICAL FUNNEL CLOUDS, WATER
SPOUTS, AND WINDS OF 30 KNOTS WITH GUSTS IN SQUALLS.

UPDATE...A VERY WELL DEVELOPED TROPICAL WAVE EAST OF CORPUS
CHRISTI AND SOUTH OF SABINE PASS HAS CONVECTION WRAPPED AROUND
THREE QUARTERS OF THE DISTURBANCE. MINOR COASTAL FLOODING IS
ONGOING AT COASTAL LOCATIONS SUCH AS CAMERON AROUND HIGH TIDE.
SINCE TIDES ARE GOING OUT...CANCELLED THE COASTAL FLOOD WATCH FOR
TODAY AND REPLACED IT WITH A COASTAL FLOOD ADVISORY. WE WILL
PROBABLY BE REISSUING THE COASTAL FLOOD WATCH FOR TONIGHT AS THE
TROPICAL WAVE CONTINUES TO SHOW SIGNS OF DEVELOPMENT.

UPDATE...DEEP TROPICAL MOISTURE WILL CONTINUE TO FLOW INTO THE
REGION BETWEEN HIGH PRESSURE OVER THE EASTERN CONUS AND AN
EASTERLY WAVE OVER THE WESTERN GULF.
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Hey StormW... yeah, my internet was acting up. Took Comcast a few days to get out here and switch out the modem. Now I'm back online... :-)

Glad I didn't miss too much.
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Quoting weathermancer:


We need more names.
How about Zwahili and German?


Hurricane Adolf....
uh, maybe not.
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Quoting weathermancer:


We need more names.
How about Zwahili and German?



good ones
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1067. That looks like it would devastate Key West, Jamaica and the Bahamas.
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1089. IKE
SYNOPSIS FOR THE GULF OF MEXICO
430 PM CDT WED JUL 07 2010

.SYNOPSIS...AN ELONGATED AREA OF LOW PRESSURE IS OVER THE
WESTERN GULF OF MEXICO NEAR 24N94W MOVING W-NW AT 8 KT. A TROUGH
EXTENDS FROM THE LOW PRES TO NEAR 29N95W. A TROPICAL DEPRESSION
COULD FORM BEFORE THE SYSTEM REACHES THE COAST OF NORTHEASTERN
MEXICO OR SOUTHERN TEXAS ON THURSDAY. HIGH PRES WILL BUILD FROM
THE E ALONG 28N FRI THROUGH MON.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Tazmanian:
you no it would be funny if they where too name evere blob out there


We need more names.
How about Zwahili and German?
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Quoting StormW:
img src="Photobucket" alt="" />

img src="Photobucket" alt="" />

img src="Photobucket" alt="" />


seems it may be going a little furthur north...
Member Since: July 2, 2009 Posts: 0 Comments: 2811

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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.