Dr. Jeff Masters' WunderBlog

The Northeast Heatwave

Posted by: Dr. Jeff Masters, 9:08 AM GMT on July 07, 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.

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1551. WatchingThisOne 12:17 AM GMT on July 08, 2010
Quoting Houstonia: 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 Trust me it was now :-) 2010 July 07 23:53:33 UTC mag 5.4 Here's the USGS link again Cali quake Member Since: July 15, 2005 Posts: 3 Comments: 1249

1553. IKE 12:18 AM GMT on July 08, 2010
248NM Brownsville radar.... Member Since: June 9, 2005 Posts: 23 Comments: 37044

1554. Drakoen 12:18 AM GMT on July 08, 2010
Quoting zoomiami: Drak - with a closed low doesn't that make it a TD? Hi everyone - forgot my manners, was a little riled by the ignorance of no AC etc. Its amazing how many people think the way they live is the only way to live. 96L is pretty much on the verge of becoming a tropical depression Member Since: October 28, 2006 Posts: 57 Comments: 29010

1555. MiamiHurricanes09 12:18 AM GMT on July 08, 2010
Quoting Drakoen: 96L is pretty much on the verge of becoming a tropical depression I would expect a renumber at any time... Member Since: September 2, 2009 Posts: 129 Comments: 19976

1556. TxMarc71 12:19 AM GMT on July 08, 2010
Quoting btwntx08: if it upgraded at 11 then more than likely we will see bonnie out this I'm almost sure this will be at least TS Bonnie by landfall..

1557. RobertM320 12:19 AM GMT on July 08, 2010
80%...hmmmm Member Since: September 27, 2007 Posts: 0 Comments: 111

1558. sailingallover 12:19 AM GMT on July 08, 2010
Quoting MiamiHurricanes09: You are only looking at convection. There are a lot of things in favor of that percentage, and if the convection was good than 96L would be a TD. Ditto.. I had just got on and looked at the Visible only when I said TD@8:00 Organization was good, vertically integrated as Levi has been waiting for all day, nice circulation. Of course when I saw the convection afterwards I said $#@!$.. Member Since: September 1, 2009 Posts: 23 Comments: 982

1559. IKE 12:19 AM GMT on July 08, 2010
Quoting MiamiHurricanes09: I would expect a renumber at any time... I'm holding my breath. Member Since: June 9, 2005 Posts: 23 Comments: 37044

1560. 900MB 12:19 AM GMT on July 08, 2010
Quoting AstroHurricane001: Earthquake in California: 5.9 is not a biggie, but very active down there lately and this one is further North than the last series, hopefully not a foreshock! Member Since: June 11, 2006 Posts: 0 Comments: 609

1561. zoomiami 12:19 AM GMT on July 08, 2010
Hi Storm-- sure you could tell a lot of stories of places without AC -- military was never one to see to all the creature comforts. By highlighting that area are you indicating that you believe it is a TD? Member Since: August 13, 2007 Posts: 10 Comments: 4064

1562. WatchingThisOne 12:19 AM GMT on July 08, 2010
Quoting melwerle: 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. Nope different spot. Member Since: July 15, 2005 Posts: 3 Comments: 1249

1563. zoomiami 12:21 AM GMT on July 08, 2010
Drak - thanks. One question I had the other day, that sad to say I've forgotten. Why is that an area will get the circle with a percentage of development, but not get an invest category? Member Since: August 13, 2007 Posts: 10 Comments: 4064

1564. MiamiHurricanes09 12:21 AM GMT on July 08, 2010
Quoting RobertM320: But you know, MH09, Hardcore's got a point. When everyone along the LA/MS coast was watching 95L, we were told to stop wasting time, it wasn't anything. Well, other than the actual breadth of the storm, 96L's pressure is no lower, winds are no higher, and circulation is no more closed than 95L's was, and yet everyone's in a tizzy.....not arguing here, just making a legitimate point. I completely understand especially considering the oil spill recovery efforts. But 96L is more organized that 95L and warrants our attention, 95L is the past, and now we have to look at the future. Member Since: September 2, 2009 Posts: 129 Comments: 19976

1565. HurricaneSwirl 12:21 AM GMT on July 08, 2010
AL, 96, 2010070800, , BEST, 0, 235N, 938W, 30, 1005, LO, 34, NEQ, 0, 0, 0, 0, 1009, 200, 65, 0, 0, L, 0, , 0, 0, INVEST, D, Those are the major changes in this ATCF update.. Member Since: July 7, 2008 Posts: 2 Comments: 3237

1566. melwerle 12:21 AM GMT on July 08, 2010
Quoting WatchingThisOne: Nope different spot. I know it's a different spot but is it the same fault line. btw 1560 - a 5.9 is big as far as I'm concerned. At least it felt that way to me! Member Since: June 28, 2006 Posts: 12 Comments: 1837

1567. IKE 12:22 AM GMT on July 08, 2010
That's got to be frightening experiencing an earthquake. Never went through one here in Florida. Apparently it wasn't a serious one...from what I've read on here. Member Since: June 9, 2005 Posts: 23 Comments: 37044

1569. HurricaneSwirl 12:23 AM GMT on July 08, 2010
They might a little while to see any start of impressive convection, it'll probably have high enough winds to be classified Bonnie by then too. Member Since: July 7, 2008 Posts: 2 Comments: 3237

1570. WatchingThisOne 12:23 AM GMT on July 08, 2010
Quoting cccidojr1: 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 !! try not to use those words: "gut feeling" Member Since: July 15, 2005 Posts: 3 Comments: 1249

1571. IKE 12:24 AM GMT on July 08, 2010
Updated image....0015UTC... Member Since: June 9, 2005 Posts: 23 Comments: 37044

1572. KarenRei 12:25 AM GMT on July 08, 2010
I just now noticed -- TS-strength winds on the northeast side: Time: 21:36:00Z Coordinates: 25.7667N 90.4167W Acft. Static Air Press: 638.8 mb (~ 18.86 inHg) Acft. Geopotential Hgt: 3,915 meters (~ 12,844 feet) Extrap. Sfc. Press: 1008.1 mb (~ 29.77 inHg) D-value: - Flt. Lvl. Wind (30s): From 136° at 35 knots (From the SE at ~ 40.2 mph) Air Temp: 5.7°C (~ 42.3°F) Dew Pt: 5.7°C (~ 42.3°F) Peak (10s) Flt. Lvl. Wind: 37 knots (~ 42.5 mph) SFMR Peak (10s) Sfc. Wind: 36 knots (~ 41.4 mph) SFMR Rain Rate: 10 mm/hr (~ 0.39 in/hr) () Denotes suspect data Pretty far from the COC, but then again, the COC on this storm is quite large currently. Member Since:* September 7, 2007 Posts: 1 Comments: 934

1573. Drakoen 12:25 AM GMT on July 08, 2010
Quoting zoomiami: Drak - thanks. One question I had the other day, that sad to say I've forgotten. Why is that an area will get the circle with a percentage of development, but not get an invest category? Whether or not something gets invest status is completely up to the forecaster. Invest status allows the forecaster to get additional information on a system such as computer models. Member Since: October 28, 2006 Posts: 57 Comments: 29010

1574. Hurricanes101 12:25 AM GMT on July 08, 2010
Quoting IKE: Updated image....0015UTC... your pic shows me 96L now has excellent structure Member Since: March 10, 2010 Posts: 1 Comments: 6902

1575. HurricaneSwirl 12:25 AM GMT on July 08, 2010
07/2345 UTC 23.8N 93.6W T1.5/1.5 Member Since: July 7, 2008 Posts: 2 Comments: 3237

1576. Levi32 12:25 AM GMT on July 08, 2010
Quoting zoomiami: Drak - thanks. One question I had the other day, that sad to say I've forgotten. Why is that an area will get the circle with a percentage of development, but not get an invest category? Invests have no required criteria and are a completely subjective declaration. Forecasters can declare an invest whenever they feel that they want to investigate a disturbance and run model forecasts on it. Member Since: November 24, 2005 Posts: 586 Comments: 25441

1577. MiamiHurricanes09 12:25 AM GMT on July 08, 2010
96L moving towards the NW between 18z and 00z ATCF coordinate fixes. Member Since: September 2, 2009 Posts: 129 Comments: 19976

1578. IKE 12:25 AM GMT on July 08, 2010
96L..looped. Member Since: June 9, 2005 Posts: 23 Comments: 37044

1579. jamesrainier 12:26 AM GMT on July 08, 2010
Quoting HurricaneSwirl: AL, 96, 2010070800, , BEST, 0, 235N, 938W, 30, 1005, LO, 34, NEQ, 0, 0, 0, 0, 1009, 200, 65, 0, 0, L, 0, , 0, 0, INVEST, D, Those are the major changes in this ATCF update.. What does LO stand for? Member Since: June 1, 2010 Posts: 0 Comments: 61

1580. zoomiami 12:26 AM GMT on July 08, 2010
Thanks Drak & Levi -- makes sense (I guess) Member Since: August 13, 2007 Posts: 10 Comments: 4064

1581. CybrTeddy 12:26 AM GMT on July 08, 2010
Quoting KarenRei: I just now noticed -- TS-strength winds on the northeast side: Time: 21:36:00Z Coordinates: 25.7667N 90.4167W Acft. Static Air Press: 638.8 mb (~ 18.86 inHg) Acft. Geopotential Hgt: 3,915 meters (~ 12,844 feet) Extrap. Sfc. Press: 1008.1 mb (~ 29.77 inHg) D-value: - Flt. Lvl. Wind (30s): From 136° at 35 knots (From the SE at ~ 40.2 mph) Air Temp: 5.7°C (~ 42.3°F) Dew Pt: 5.7°C (~ 42.3°F) Peak (10s) Flt. Lvl. Wind: 37 knots (~ 42.5 mph) SFMR Peak (10s) Sfc. Wind: 36 knots (~ 41.4 mph) SFMR Rain Rate: 10 mm/hr (~ 0.39 in/hr) () Denotes suspect data Pretty far from the COC, but then again, the COC on this storm is quite large currently. They might make this directly to TS Bonnie if this is the case. Member Since:* July 8, 2005 Posts: 253 Comments: 20179

1582. MiamiHurricanes09 12:26 AM GMT on July 08, 2010
SAB up to 1.5. Let's see what the TAFB and CIRA show. Member Since: September 2, 2009 Posts: 129 Comments: 19976

1583. MiamiHurricanes09 12:27 AM GMT on July 08, 2010
Quoting jamesrainier: What does LO stand for? Low. Member Since: September 2, 2009 Posts: 129 Comments: 19976

1584. skkippboo 12:27 AM GMT on July 08, 2010
Wind shifted to the NNE this morning here in S. Tex. I knew then the low was getting deeper and closer. Have had some passing showers today. Skeeters are loving it!! Member Since: April 19, 2009 Posts: 0 Comments: 132

1586. houstongator 12:28 AM GMT on July 08, 2010
Quoting zoomiami: Hi Storm-- sure you could tell a lot of stories of places without AC -- military was never one to see to all the creature comforts. By highlighting that area are you indicating that you believe it is a TD? I spent my childhood growing up in Army housing and we only had AC when we got down in Alabama. In Illinois we had to put in our own window units. The day my dad bought a cheap one and put in my room is one of the most memorable days of my life. Member Since: August 28, 2005 Posts: 0 Comments: 109

1587. HurricaneSwirl 12:28 AM GMT on July 08, 2010
Quoting jamesrainier: What does LO stand for? Low. Other abbreviations they use: DB=Disturbance WV=Wave TD=Tropical Depression TS=Tropical Storm HU=Hurricane Member Since: July 7, 2008 Posts: 2 Comments: 3237

1588. HaboobsRsweet 12:28 AM GMT on July 08, 2010
Quoting CybrTeddy: They might make this directly to TS Bonnie if this is the case. depends...if it is far from center and just associated with a thunderstorm and not gradient winds they will throw that one out. Its a tough call. Member Since: May 20, 2009 Posts: 0 Comments: 1640

1589. CybrTeddy 12:28 AM GMT on July 08, 2010
Alright, if they do call 96L a TD (or maybe even a TS, judging by recon's SFMR reading) at 11 you'll want to look for these things. 1) ATCF saying 'renumber from al96 to al02 2) NRL taking down 96L 3) NRL putting up 02L.NONAME Member Since: July 8, 2005 Posts: 253 Comments: 20179

1590. Levi32 12:29 AM GMT on July 08, 2010
".....ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS. $$ FORECASTER STEWART/CANGIALOSI NNNN" I could be brain-glitching but I don't recall seeing this guy before. Member Since: November 24, 2005 Posts: 586 Comments: 25441

1591. BahaHurican 12:29 AM GMT on July 08, 2010
Evening everybody... interesting to see 96L look like it may finally get something together.... Quoting weatherman12345: I think they should have put the area east of the Bahamas on a low potential. Maybe tomorrow if it's still there they'll consider it. Such areas really need to persist long enough to develop a LLC, and while there is some vorticity in the area, I have a feeling it's not down to the surface. BTW, did anybody look at the Discussion? TROPICAL WAVE IS APPROACHING THE W AFRICA COAST ALONG 15W/16W S OF 17N. A NORTHERN LOW-LEVEL DRY VORTICITY CENTER IS NEAR THE NRN EXTEND OF THE WAVE AXIS ANALYZED AS A 1006 MB LOW NEAR 17N15W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-9N BETWEEN 12W-19W. This one already has a low analysed at the northern end! I have a feeling this is going to help pull the ITCZ up towards or over 10, and may in fact signal the beginning of CV season.... but we shall see what we shall see.... Member Since: October 25, 2005 Posts: 19 Comments: 17588

1592. zoomiami 12:29 AM GMT on July 08, 2010
Quoting houstongator: I spent my childhood growing up in Army housing and we only had AC when we got down in Alabama. In Illinois we had to put in our own window units. The day my dad bought a cheap one and put in my room is one of the most memorable days of my life. Yep -- in NJ we could only have window units. However, I refused to move to Key West unless they had central air! lol Member Since: August 13, 2007 Posts: 10 Comments: 4064

1593. Story 12:29 AM GMT on July 08, 2010
The last mandatory evac for the Corpus Christi area was for Rita. I have lived in Corpus all my life and they will evac the island for a Cat 1 that comes too close... they base the evac warning on the tides for the Kennedy Causeway, usually several days in advance. They will can a county-wide evac if we are landfall, for anything North of a strong Cat 2, or massive rains that will inhibit city functions. At least that is how they have worked it in the past. I for one, seldom leave the area... it would take a Rita to move me out again...

1594. Patrap 12:29 AM GMT on July 08, 2010
00z Early Cycle NHC model tracks Invest96 Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models) Dynamic Models (More sophisticated models) Early Model Wind Forecasts Member Since: July 3, 2005 Posts: 370 Comments: 111244

1595. HurricaneSwirl 12:30 AM GMT on July 08, 2010
Quoting Levi32: ".....ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS. $$ FORECASTER STEWART/CANGIALOSI NNNN" I could be brain-glitching but I don't recall seeing this guy before. He's been paired up with Stewart for a while I think. I know for sure he was with Stewart during that Special TWO when 95L got upped to 60%. Member Since: July 7, 2008 Posts: 2 Comments: 3237

1596. txwxnut2 12:30 AM GMT on July 08, 2010
notice the nice outflow/expansion on the north side of the center. Member Since: August 26, 2006 Posts: 0 Comments: 68

1597. CybrTeddy 12:30 AM GMT on July 08, 2010
Quoting HaboobsRsweet: depends...if it is far from center and just associated with a thunderstorm and not gradient winds they will throw that one out. Its a tough call. Yea Hal, that might be what they're dealing with. Member Since: July 8, 2005 Posts: 253 Comments: 20179

1598. IKE 12:30 AM GMT on July 08, 2010
Quoting Levi32: ".....ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS. $$ FORECASTER STEWART/CANGIALOSI NNNN" I could be brain-glitching but I don't recall seeing this guy before. He's 1 of the 2 that raised 95L from near 0 to 60. Member Since: June 9, 2005 Posts: 23 Comments: 37044

1599. JLPR2 12:30 AM GMT on July 08, 2010
Quoting IKE: Updated image....0015UTC... Well lol, there goes the convection :O Member Since: September 4, 2007 Posts: 7 Comments: 7487

1600. Levi32 12:31 AM GMT on July 08, 2010
Quoting IKE: He's 1 of the 2 that raised 95L from near 0 to 60. Right ok but anyone recall seeing him prior to that? It looks like a new face to me, but I'm not completely familiar with the NHC staff and who all's on it besides the forecasters who regularly write the TC advisories/outlooks/discussions. Member Since: November 24, 2005 Posts: 586 Comments: 25441

1601. CybrTeddy 12:31 AM GMT on July 08, 2010
96L has good structure. Reminds me of Erin 2007. Member Since: July 8, 2005 Posts: 253 Comments: 20179

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