Dr. Jeff Masters' WunderBlog

The Northeast Heatwave

Posted by: Dr. Jeff Masters, 09:08 GMT le 07 juillet 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.

Categories: Heat

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901. angiest 20:15 GMT le 07 juillet 2010
Quoting KarenRei: Oh great... thanks, ECMWF: 2010's goal is apparently to wash Laredo and Brownsville off the map. That forecast is most of a week old now. It looks wrong on the intensity but the location is fairly good, it would appear. Member Since: 26 août 2006 Posts: 16 Comments: 4766

902. Hurricanes101 20:15 GMT le 07 juillet 2010
............ Member Since: 10 Mars 2010 Posts: 1 Comments: 6902

903. IKE 20:16 GMT le 07 juillet 2010
87.6 at my location....humid and sunny. Member Since: 9 juin 2005 Posts: 23 Comments: 37044

904. ElConando 20:16 GMT le 07 juillet 2010
Quoting StormW: No...if the upper level low organizes to the surface, it may cross FL., or it may stall and head out to sea. If the area of convection to the south of that becomes the feature to watch, it should head out to sea. my bad got crossed up between the two. Thank you for the clarification though. Member Since: 6 septembre 2009 Posts: 2 Comments: 3703

905. KarenRei 20:16 GMT le 07 juillet 2010
Quoting MiamiHurricanes09: That graph is from July 2nd. I caught my ECMWF bookmark's mistake right after I submitted the post... but apparently I couldn't edit it fast enough for all of you ;) Member Since: 7 septembre 2007 Posts: 1 Comments: 934

906. whipster 20:16 GMT le 07 juillet 2010
Quoting wunderkidcayman: HEY GUYS GUESS WHAT JUST HAPPEN TO ME I WAS GIVING A FRIEND OF MINE A WEATHER REPORT SHE IS A HAIR DRESSER AND SHE HAD THE PHONE ON SPEAKER SO EVERYONE COULD HEAR AND THIS GUY THAT HEARD IT CAME UP AND SPOKE TO ME ON THE PHONE HE IS THE DIRECTOR OF CITN/WESTSTAR OUR TV/NEWS NETWORK HERE IN CAYMAN AND HE ASKED ME TO MEET WITH HIM SO THIS IS JUST GREAT Sounds like a nice job...most days are "sunny and warm, light breeze" Member Since: 14 août 2007 Posts: 0 Comments: 422

907. sebastianflorida 20:17 GMT le 07 juillet 2010
So, my luck is bahama feature develops, does a loop, lands in my yard Member Since: 5 août 2007 Posts: 0 Comments: 509

908. MiamiHurricanes09 20:17 GMT le 07 juillet 2010
Quoting ElConando: Hopefully it won't re intensify over land. I'm sure it won't. But hey, ya' never know with these systems. Member Since: 2 septembre 2009 Posts: 129 Comments: 19976

909. watchingnva 20:17 GMT le 07 juillet 2010
Quoting FLdewey: wunderkidcayman... caps lock key is usually below the tab key, above the shift key. Hit it. ...there was excitement involved...cut some slack... Member Since: 7 septembre 2005 Posts: 3 Comments: 1310

910. CoopsWife 20:17 GMT le 07 juillet 2010
Quoting watchingnva:F my ac is too old for this...lol... Mine was too, but the install of the new one is complete and we're now below 80 in the house - WOO HOO! Member Since: 19 juin 2006 Posts: 63 Comments: 4167

911. angiest 20:17 GMT le 07 juillet 2010
Area forecast discussion National Weather Service Houston/Galveston Texas 1227 PM CDT Wednesday Jul 7 2010 Aviation... deja vu all over again. Deep tropical airmass and associated waves of rainfall moving through the region expect this to continue for the next 36 hours. Tough to impossible to pin down timing as to specifics regarding timing/intensity at each individual taf site. Overall...expect the heaviest rainfall to occur overnight and Thursday as increased moisture and better surface convergence/ boundary in the area. Generally advertised MVFR/IFR ceilings and light rain as prevailing along with vcts's. There's no doubt there will be several amendments necessary (most likely for the worse) once timing/confidence is somewhat better but didn't want to go with 24-36 hours Worth of tempos. 47 && Discussion... went ahead and started the Flash Flood Watch to begin now instead of this evening considering coverage/intensity of precipitation. Still think flood issues will be more isolated in nature during the day with an increasing threat overnight and Thursday. Member Since: 26 août 2006 Posts: 16 Comments: 4766

912. Squid28 20:18 GMT le 07 juillet 2010
Quoting AllBoardedUp: I can't imagine a Katrina type of storm surge hitting south of Galveston/Houston area! I know Katrina was probably the exception and not the rule, but it still possible. It's a matter of when, not it it'll happen. But of course, the "when" might not happen in our life times. One thing that a lot of people do not realize also is that while being on the western side of the eyewall is worse, the angle of the storms approach/landfall also has some effect on the severity of the surge as well. Member Since: 23 mai 2006 Posts: 0 Comments: 343

913. itrackstorms 20:18 GMT le 07 juillet 2010
Sure looks like she is getting close.... Member Since: 20 juillet 2008 Posts: 0 Comments: 152

914. SavannahStorm 20:18 GMT le 07 juillet 2010
Pretty good pressure drop in the Bahamas wave/ ULL area. Member Since: 22 septembre 2005 Posts: 18 Comments: 2135

915. atmoaggie 20:19 GMT le 07 juillet 2010
. (since it seems that everyone else is having a lot of fun posting a period) Member Since: 16 août 2007 Posts: 6 Comments: 12461

917. AllBoardedUp 20:20 GMT le 07 juillet 2010
Quoting extreme236: GOTTA LOVE THAT CAPS LOCK BUTTON, HUH? I see it both ways on here! Some people don't ever use the caps and type in all lower case letters. What ever happened to beginning a sentence with a upper case letter. In both instances, I believe it is laziness. Anyway, congratulations on your opportunity. Member Since: 25 juillet 2008 Posts: 0 Comments: 585

918. angiest 20:21 GMT le 07 juillet 2010
Quoting Squid28: One thing that a lot of people do not realize also is that while being on the western side of the eyewall is worse, the angle of the storms approach/landfall also has some effect on the severity of the surge as well. Storms striking Texas seem to hit at close to perpendicular to the coast. You can look through the database and see some that hit at odd angles, but they appear to be the exception. Member Since: 26 août 2006 Posts: 16 Comments: 4766

921. atmoaggie 20:22 GMT le 07 juillet 2010
Quoting Squid28: One thing that a lot of people do not realize also is that while being on the western side of the eyewall is worse, the angle of the storms approach/landfall also has some effect on the severity of the surge as well. ? east side is normally the worst for a south to north mover. That said, west side can sometimes have higher individual gust instances due to the turbulence of winds flowing over the land than on-shore winds on the east side. And the west side commonly has drier air, which can raise wind gusts in the presence of downbursts higher than if in moist air. Member Since: 16 août 2007 Posts: 6 Comments: 12461

922. hydrus 20:23 GMT le 07 juillet 2010
Member Since: 27 septembre 2007 Posts: 1 Comments: 14297

923. DellOperator 20:24 GMT le 07 juillet 2010
Quoting atmoaggie: . (since it seems that everyone else is having a lot of fun posting a period) .. I see your period and raise you one. Member Since: 31 mai 2007 Posts: 0 Comments: 175

924. AllBoardedUp 20:24 GMT le 07 juillet 2010
Temporary slack in the rain! Need to run errands. Member Since: 25 juillet 2008 Posts: 0 Comments: 585

926. SavannahStorm 20:25 GMT le 07 juillet 2010
The East Coast ULL is considerably moist, and is in the vicinity of some low and dropping surface pressures. It may have a shot at working itself to the surface. Member Since: 22 septembre 2005 Posts: 18 Comments: 2135

927. Drakoen 20:25 GMT le 07 juillet 2010
Member Since: 28 octobre 2006 Posts: 57 Comments: 29010

928. Levi32 20:26 GMT le 07 juillet 2010
Quoting atmoaggie: ? east side is normally the worst for a south to north mover. That said, west side can sometimes have higher individual gust instances due to the turbulence of winds flowing over the land than on-shore winds on the east side. And the west side commonly has drier air, which can raise wind gusts in the presence of downbursts higher than if in moist air. Great point. Member Since: 24 novembre 2005 Posts: 586 Comments: 25450

929. extreme236 20:26 GMT le 07 juillet 2010
Quoting Drakoen: Convection becoming more concentrated. Looks like it's developing into a tropical cyclone. Member Since: 2 août 2007 Posts: 19 Comments: 19234

930. MiamiHurricanes09 20:26 GMT le 07 juillet 2010
After checking out latest satellite imagery, surface observations, CIMSS 18:00 UTC products, and ASCAT, the NHC should raise the chance of development in the next 48 hours to 70%. Member Since: 2 septembre 2009 Posts: 129 Comments: 19976

931. hydrus 20:26 GMT le 07 juillet 2010
Link.....96L is moving fast. Wont have much time. Member Since: 27 septembre 2007 Posts: 1 Comments: 14297

932. atmoaggie 20:27 GMT le 07 juillet 2010
Quoting DellOperator: .. I see your period and raise you one. All in. Member Since: 16 août 2007 Posts: 6 Comments: 12461

933. ccSparky 20:27 GMT le 07 juillet 2010
Where are you all thinking this 96L is going to hit. Have not seen anything recent.

934. extreme236 20:28 GMT le 07 juillet 2010
Quoting MiamiHurricanes09: After checking out latest satellite imagery, surface observations, CIMSS 18:00 UTC products, and ASCAT, the NHC should raise the chance of development in the next 48 hours to 70%. If the NHC does say a tropical depression is forming...the chances would be 90%-nearly 100%. But that's only if they use that wording. Member Since: 2 août 2007 Posts: 19 Comments: 19234

935. DellOperator 20:28 GMT le 07 juillet 2010
Quoting atmoaggie: ? east side is normally the worst for a south to north mover. That said, west side can sometimes have higher individual gust instances due to the turbulence of wins flowing over the land than on-shore winds on the east side. And the west side commonly has drier air, which can raise wind gusts in the presence of downbursts higher than if in moist air. I was always instructed to use RFQ (right front quadrant) instead of using east and west terminology. It all depends on the relative motion of the circulation. And depending on where you are on this oblique spheroid we live on, that can make a difference. Member Since: 31 mai 2007 Posts: 0 Comments: 175

936. MiamiHurricanes09 20:28 GMT le 07 juillet 2010
Quoting ccSparky: Where are you all thinking this 96L is going to hit. Have not seen anything recent. Interests along northern Mexico, southern Texas, and central Texas should all watch 96L with southern Texas having the highest chance of landfall. Member Since: 2 septembre 2009 Posts: 129 Comments: 19976

938. atmoaggie 20:29 GMT le 07 juillet 2010
Quoting DellOperator: I was always instructed to use RFQ (right front quadrant) instead of using east and west terminology. It all depends on the relative motion of the circulation. And depending on where you are on this oblique spheroid we live on, that can make a difference. Correct! Procrastination time exhausted, back at it. L8R. Member Since: 16 août 2007 Posts: 6 Comments: 12461

939. DellOperator 20:29 GMT le 07 juillet 2010
Quoting atmoaggie: All in. I fold. :) Looks like a Monte Carlo distribution pattern. Nice one ATMO. Member Since: 31 mai 2007 Posts: 0 Comments: 175

940. USSINS 20:29 GMT le 07 juillet 2010
Reading "intermittently", but looks like it's spitting out some data at least. And, considering the location and the recent high traffic volume, this bouy would be a good tool to have up and working. Station 42002 (LLNR 1405) - W GULF 207 NM East of Brownsville, TX 10-meter discus buoy ARES payload 25.790 N 93.666 W Site elevation: sea level Air temp height: 10 m above site elevation Anemometer height: 10 m above site elevation Barometer elevation: sea level Sea temp depth: 1 m below site elevation Water depth: 3566.16 m Watch circle radius: 3523 yards 42002 is transmitting intermittently. *This buoy will be serviced when it can be worked into the schedule. When the service date is known, it will be posted in the maintenance report.* Wind Speed (WSPD): 19.4 kts Wind Gust (GST): 21.4 kts Atmospheric Pressure (PRES): 29.78 in Pressure Tendency (PTDY): +0.02 in ( Rising ) Air Temperature (ATMP): 80.6 °F Water Temperature (WTMP): 84.4 °F

941. MiamiHurricanes09 20:30 GMT le 07 juillet 2010
Quoting extreme236: If the NHC does say a tropical depression is forming...the chances would be 90%-nearly 100%. But that's only if they use that wording. Probably. Honestly I would give 96L a 90% chance in the next 48 hours, but considering how the NHC might want to tone it down a bit since recon has not investigated, 70% would be a good bet. Member Since: 2 septembre 2009 Posts: 129 Comments: 19976

942. Drakoen 20:30 GMT le 07 juillet 2010
Quoting extreme236: Convection becoming more concentrated. Looks like it's developing into a tropical cyclone. Yup Member Since: 28 octobre 2006 Posts: 57 Comments: 29010

943. ccSparky 20:31 GMT le 07 juillet 2010
Thank you - MiamiHurricanes09

944. extreme236 20:31 GMT le 07 juillet 2010
If this becomes classified as I expect, then it will be done before recon I'm sure. Hopefully we get the chance to put recon in it before landfall though. Member Since: 2 août 2007 Posts: 19 Comments: 19234

945. atmoaggie 20:32 GMT le 07 juillet 2010
Quoting USSINS: Reading "intermittently", but looks like it's spitting out some data at least. And, considering the location and the recent high traffic volume, this bouy would be a good tool to have up and working. But, without a wind direction reading, I have trouble trusting the wind speeds. What if the anemometer isn't swinging the face the winds correctly? And how come we don't have wind direction? I know for a fact that this one is supposed to have 2 anemometers. Are they both not functioning correctly? Member Since: 16 août 2007 Posts: 6 Comments: 12461

946. AustinTXWeather 20:33 GMT le 07 juillet 2010
Quoting MiamiHurricanes09: Interests along northern Mexico, southern Texas, and central Texas should all watch 96L with southern Texas having the highest chance of landfall. What's the thinking on Central Texas watching? Welcome the info - Member Since: 13 septembre 2008 Posts: 0 Comments: 241

947. Squid28 20:34 GMT le 07 juillet 2010
Quoting atmoaggie: ? east side is normally the worst for a south to north mover. That said, west side can sometimes have higher individual gust instances due to the turbulence of winds flowing over the land than on-shore winds on the east side. And the west side commonly has drier air, which can raise wind gusts in the presence of downbursts higher than if in moist air. DOOOH, You are right, I flubbed that pretty good. I was thinking angle of approach when typing the original entry and somehow combined the two into one tangled mess. Member Since: 23 mai 2006 Posts: 0 Comments: 343

949. USSINS 20:35 GMT le 07 juillet 2010
Quoting atmoaggie: But, without a wind direction reading, I have trouble trusting the wind speeds. What if the anemometer isn't swinging the face the winds correctly? And how come we don't have wind direction? I know for a fact that this one is supposed to have 2 anemometers. Are they both not functioning correctly? Great questions, Atmo. I certainly dunno. Checked the maintenance chart, didn't see a date scheduled for repair yet either. May be kind of tough to dart out there in between TDs. Oh, wait, this one's not a TD yet either. ;P

950. MiamiHurricanes09 20:35 GMT le 07 juillet 2010
Quoting AustinTXWeather: What's the thinking on Central Texas watching? Welcome the info - They should definitely watch 96L but probably won't get the "brunt" of it. Up there you'll probably get some rain and gusts nothing big though. 18z (statistical) and 12z (dynamic) model runs. Member Since: 2 septembre 2009 Posts: 129 Comments: 19976

951. DellOperator 20:36 GMT le 07 juillet 2010
Quoting atmoaggie: But, without a wind direction reading, I have trouble trusting the wind speeds. What if the anemometer isn't swinging the face the winds correctly? And how come we don't have wind direction? I know for a fact that this one is supposed to have 2 anemometers. Are they both not functioning correctly? Ever hear of birds resting on the instruments out at sea? Hard to believe redundancy has failed. Member Since: 31 mai 2007 Posts: 0 Comments: 175

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