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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1437. Dakster
Nraamy? Where?
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How much crow we grillin tonight?? LOL
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Red and at 80%!
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1433. JLPR2
dang 80% that surprised me a little considering 96L's weak convection, maybe the LLC is doing better than the convection :P
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yeah - that Line of T-storms was probably worse than what we're going to get out of this guy - we had a couple wx stations report gusts to 90mph.
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1431. Levi32
Apparently the NHC is impressed. The only thing keeping this from being classified right now is the lack of deep convection, as cloud tops are rather shallow right now. As they mention, if the current rate of organization continues it should be a TD later tonight or tomorrow morning.
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1430. IKE
LMAO!

80%!

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Quoting Hurricanes101:


The buoy in the west central Gulf already found a closed center earlier today, also the NHC has the percentage at 50% already

ah fair enough...didnt see buoy data. They still typically dont call it until the HH do an invest mission and find the center themselves. Looks like they are going in to look for it.
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Where's my cookie?
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1427. NRAamy
EARTHQUAKE!!!!!!!
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Just experienced an EQ in SoCal. Looking it up ...
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im actually shocked. but i posted the outlook first. :D
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1424. Daveg
Wow, went to 80%.... I was leaning 60%....

Definitely pulling itself together.
Member Since: September 23, 2005 Posts: 0 Comments: 426
.

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96L has been organizing thru-out the day,make no mistake about it,TD tomorrow,maybe TS IMO....
Member Since: October 5, 2007 Posts: 20 Comments: 4970
Quoting Daveg:


Definitely not moving West or WNW.


I thought it was going to stay on a wnw track.
Member Since: July 2, 2009 Posts: 0 Comments: 2811
1419. Drakoen
WOW 80& chance
Member Since: October 28, 2006 Posts: 57 Comments: 30575
1418. Becca36
Wow! 80%!
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1416. IKE
Well...I must be an idiot. Glad I don't do this for a living.
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Quoting IKE:
F5...F5.....refresh...refresh...F5....F5....

Hi Ike, I like the way you always hype these systems....LOL
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Quoting StSimonsIslandGAGuy:
TxMarc many people in the northeast have no air conditioning, and they are not as used to triple digit temperatures. By such logic, the 1995 Chicago heat disaster did not happen.

I am a south GA native, and inland especially prolonged heat is common. But I recognize that record heat such as has been happening in the northeast can be extremely dangerous.


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...
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Up to 80%!
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Quoting txwxnut2:
Corpus christi - wind and lots of rain. kinda like an april day, but add rain - LOL! recall the 50mph winds we had this past April/May w/ no storm. Also, tides 2-4ft above normal; unless this thing pulls a claudette or humberto...


we had areas with 70 plus gusts here not long ago. Even had some people lose power
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wow 80% lmao
Member Since: March 10, 2010 Posts: 1 Comments: 7829
lol 80%
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Quoting MiamiHurricanes09:
The same could have been said about 95L... Please stop with those type of comments unless you want to be banned.

banned because he doesnt think it will be a TD before it gets inland? whew.
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80%!
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1406. Dakster
RED ALERT, RED ALERT....

This is not a drill.
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1405. Levi32
.
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96L could remain 96L until landfall.
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1403. SLU
000
ABNT20 KNHC 072353
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT WED JUL 7 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A LARGE LOW PRESSURE SYSTEM LOCATED ABOUT 290 MILES SOUTHEAST OF THE
TEXAS/MEXICO BORDER IS MOVING WEST-NORTHWESTWARD AT 10 TO 15 MPH.
THIS SYSTEM HAS BECOME MUCH BETTER ORGANIZED THIS AFTERNOON AND
EVENING...AND THUNDERSTORM ACTIVITY HAS BECOME MORE CONCENTRATED
NEAR THE CENTER. TWO NOAA RECONNAISSANCE AIRCRAFT ARE CURRENTLY
CONDUCTING A RESEARCH MISSION IN AND AROUND THE DISTURBANCE...AND
INFORMATION RECEIVED SO FAR SUGGESTS THAT A TROPICAL DEPRESSION MAY
BE FORMING. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR FURTHER
DEVELOPMENT AND IF ADDITIONAL ORGANIZATION CONTINUES...THEN
FORECAST ADVISORIES WILL BE INITIATED LATER TONIGHT OR THURSDAY
MORNING...WHICH WOULD REQUIRE THAT TROPICAL STORM WATCHES OR
WARNINGS BE ISSUED FOR PORTIONS OF THE COASTAL REGIONS OF CENTRAL
AND LOWER TEXAS AND NORTHEASTERN MEXICO. THERE IS A HIGH
CHANCE...80 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE.
THIS DISTURBANCE IS FORECAST TO BRING LOCALLY HEAVY RAINS AND GUSTY
WINDS TO PORTIONS OF EASTERN AND SOUTHERN TEXAS AND NORTHEASTERN
MEXICO OVER THE NEXT FEW DAYS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
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Quoting HaboobsRsweet:
This system will not be a TD until the HH fly and find a closed low which at the moment doesnt look good. I doubt we see red either. It might go to 50% orange or something along those lines but got to watch for the flight. There is little progress and its only hope is if they find a closed center.


The buoy in the west central Gulf already found a closed center earlier today, also the NHC has the percentage at 50% already
Member Since: March 10, 2010 Posts: 1 Comments: 7829
000
ABNT20 KNHC 072353
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT WED JUL 7 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A LARGE LOW PRESSURE SYSTEM LOCATED ABOUT 290 MILES SOUTHEAST OF THE
TEXAS/MEXICO BORDER IS MOVING WEST-NORTHWESTWARD AT 10 TO 15 MPH.
THIS SYSTEM HAS BECOME MUCH BETTER ORGANIZED THIS AFTERNOON AND
EVENING...AND THUNDERSTORM ACTIVITY HAS BECOME MORE CONCENTRATED
NEAR THE CENTER. TWO NOAA RECONNAISSANCE AIRCRAFT ARE CURRENTLY
CONDUCTING A RESEARCH MISSION IN AND AROUND THE DISTURBANCE...AND
INFORMATION RECEIVED SO FAR SUGGESTS THAT A TROPICAL DEPRESSION MAY
BE FORMING. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR FURTHER
DEVELOPMENT AND IF ADDITIONAL ORGANIZATION CONTINUES...THEN
FORECAST ADVISORIES WILL BE INITIATED LATER TONIGHT OR THURSDAY
MORNING...WHICH WOULD REQUIRE THAT TROPICAL STORM WATCHES OR
WARNINGS BE ISSUED FOR PORTIONS OF THE COASTAL REGIONS OF CENTRAL
AND LOWER TEXAS AND NORTHEASTERN MEXICO. THERE IS A HIGH
CHANCE...80 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE.
THIS DISTURBANCE IS FORECAST TO BRING LOCALLY HEAVY RAINS AND GUSTY
WINDS TO PORTIONS OF EASTERN AND SOUTHERN TEXAS AND NORTHEASTERN
MEXICO OVER THE NEXT FEW DAYS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
Member Since: Posts: Comments:
LARGE LOW PRESSURE SYSTEM LOCATED ABOUT 290 MILES SOUTHEAST OF THE
TEXAS/MEXICO BORDER IS MOVING WEST-NORTHWESTWARD AT 10 TO 15 MPH.
THIS SYSTEM HAS BECOME MUCH BETTER ORGANIZED THIS AFTERNOON AND
EVENING...AND THUNDERSTORM ACTIVITY HAS BECOME MORE CONCENTRATED
NEAR THE CENTER. TWO NOAA RECONNAISSANCE AIRCRAFT ARE CURRENTLY
CONDUCTING A RESEARCH MISSION IN AND AROUND THE DISTURBANCE...AND
INFORMATION RECEIVED SO FAR SUGGESTS THAT A TROPICAL DEPRESSION MAY
BE FORMING. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR FURTHER
DEVELOPMENT AND IF ADDITIONAL ORGANIZATION CONTINUES...THEN
FORECAST ADVISORIES WILL BE INITIATED LATER TONIGHT OR THURSDAY
MORNING...WHICH WOULD REQUIRE THAT TROPICAL STORM WATCHES OR
WARNINGS BE ISSUED FOR PORTIONS OF THE COASTAL REGIONS OF CENTRAL
AND LOWER TEXAS AND NORTHEASTERN MEXICO. THERE IS A HIGH
CHANCE...80 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE.
THIS DISTURBANCE IS FORECAST TO BRING LOCALLY HEAVY RAINS AND GUSTY
WINDS TO PORTIONS OF EASTERN AND SOUTHERN TEXAS AND NORTHEASTERN
MEXICO OVER THE NEXT FEW DAYS.
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@HouGalv08,are you anticipating ongoing showers there even if it makes landfall in Mexico?
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I love yellow :) Time for a 10%
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1397. Daveg
Quoting TexasHurricane:


It is moving NW now?


Definitely not moving West or WNW.
Member Since: September 23, 2005 Posts: 0 Comments: 426
This system will not be a TD until the HH fly and find a closed low which at the moment doesnt look good. I doubt we see red either. It might go to 50% orange or something along those lines but got to watch for the flight. There is little progress and its only hope is if they find a closed center.
Member Since: Posts: Comments:
Corpus christi - wind and lots of rain. kinda like an april day, but add rain - LOL! recall the 50mph winds we had this past April/May w/ no storm. Also, tides 2-4ft above normal; unless this thing pulls a claudette or humberto...
Member Since: Posts: Comments:
1394. leo305
It looks bad convectively sure.. but at the surface it's becoming better organized.. and that matters alot when it comes to development
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I think a few are over-analyzing the analysis of 96L lol

I guess watching 96L means we all think it will be a hurricane lol
Member Since: March 10, 2010 Posts: 1 Comments: 7829
1392. IKE
Quoting reedzone:


I agree, I"m still not impressed with 96L. I'm looking to see a yellow circle over the NON-TROPICAL (Reed) Low.


Convection has waned....yeah, I know about DMIN...plus it looks stretched out still. It looked better earlier this afternoon then it does now.
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Quoting Levi32:


Nearly impossible, I would go so far as to say.


That is good news
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1390. IKE
F5...F5.....refresh...refresh...F5....F5....
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Quoting IKE:
If this is 70% I'm either blind or an idiot or both....





I agree, I"m still not impressed with 96L. I'm looking to see a yellow circle over the NON-TROPICAL (Reed) Low.
Member Since: July 1, 2008 Posts: 13 Comments: 7396
just a trace of rain in Corpus so far.
Houston looked like it got some heavy rain earlier on the radar
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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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