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.

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1201. Daveg 22:37 GMT le 07 juillet 2010
Well it ain't purty... but it is starting to effect more and more of the gulf... Member Since: 23 septembre 2005 Posts: 0 Comments: 426

1203. Drakoen 22:38 GMT le 07 juillet 2010
Quoting nrtiwlnvragn: I think thats the P3. G-IV only reports dropsondes. Yes Member Since: 28 octobre 2006 Posts: 57 Comments: 29012

1204. KoritheMan 22:38 GMT le 07 juillet 2010
Quoting calder: i appreciate that too, im just saying that there are actually very few people on this blog that give a balanced and non-bias prediction usually. I agree weak TS at worst case. Ppl this week been calling for cat 3 tho consistently... None of the really knowledgeable people would say that. Are you sure you've been studying the right people? Member Since: 7 Mars 2007 Posts: 421 Comments: 15643

1205. reedzone 22:38 GMT le 07 juillet 2010
Quoting calder: i appreciate that too, im just saying that there are actually very few people on this blog that give a balanced and non-bias prediction usually. I agree weak TS at worst case. Ppl this week been calling for cat 3 tho consistently... When 96L was in the Caribbean, I didn't rule out a Hurricane for Texas/LA, I thought models were too south, which for the first circulation, they were. Now my thinking is South Texas. It hasn't been able to get going much, I have my doubts, but we'll see what tonight brings. Member Since: 1 juillet 2008 Posts: 13 Comments: 7249

1206. Hurricanes101 22:39 GMT le 07 juillet 2010
Quoting nrtiwlnvragn: From Brownsville WFO FINALLY...THERE WILL BE A SMALL RISK FOR ISOLATED TROPICAL FUNNELS AND TORNADOES IN RAINBANDS DURING THE DAY ON THURSDAY ACROSS SOUTH TEXAS. Tropical Funnels = ? Tornado vortex that does not reach the ground? Wonder if tropical funnels have little paper umbrellas in them :P Member Since: 10 Mars 2010 Posts: 1 Comments: 6930

1207. hurricaster 22:39 GMT le 07 juillet 2010
Anybody have a guesstimate of the surface center location and current movement. Member Since: 22 juillet 2008 Posts: 0 Comments: 109

1208. calder 22:40 GMT le 07 juillet 2010
Quoting KoritheMan: None of the really knowledgeable people would say that. Are you sure you've been studying the right people? maybe it was taz messing about, but i stick to what i said, it's been really apparent over the last few weeks.. Anyways, im out, bedtime in scotland. night Member Since: 26 juillet 2006 Posts: 0 Comments: 412

1210. Daveg 22:41 GMT le 07 juillet 2010
Quoting hurricaster: Anybody have a guesstimate of the surface center location and current movement. Last NHC fix was Coordinates: 23.8N 93.6W It hasn't moved just a ton since that last fix. Member Since: 23 septembre 2005 Posts: 0 Comments: 426

1211. WindynEYW 22:41 GMT le 07 juillet 2010
Quoting StormW: Tropical Funnel: Def. A device for pouring a tropical drink into ones person. lmao ttf Member Since: 13 septembre 2007 Posts: 0 Comments: 331

1212. GeoffreyWPB 22:41 GMT le 07 juillet 2010
Quoting KoritheMan: None of the really knowledgeable people would say that. Are you sure you've been studying the right people? I agree. I do not recall any of the knowledgeable bloggers calling for a Cat. 3. Member Since: 10 septembre 2007 Posts: 0 Comments: 9248

1214. MiamiHurricanes09 22:41 GMT le 07 juillet 2010
Quoting calder: i appreciate that too, im just saying that there are actually very few people on this blog that give a balanced and non-bias prediction usually. I agree weak TS at worst case. Ppl this week been calling for cat 3 tho consistently... I haven't heard anyone say that 96L will become a CAT 3. (except for Taz but he is just kidding). Member Since: 2 septembre 2009 Posts: 129 Comments: 20003

1215. CJC111 22:41 GMT le 07 juillet 2010
Have to agree with calder. Usually, I'm lurking because I find the knowledge here and the weather fascinating. I do remember a couple of days ago there was more than 1 that called for a moderate to severe hurricane.

1216. wxvoyeur 22:42 GMT le 07 juillet 2010
Quoting StormW: Tropical Funnel: Def. A device for pouring a tropical drink into ones person. So the Brownsville WFO is spot on then! ;) Member Since: 26 juin 2010 Posts: 0 Comments: 100

1217. TxMarc71 22:42 GMT le 07 juillet 2010
Quoting calder: i appreciate that too, im just saying that there are actually very few people on this blog that give a balanced and non-bias prediction usually. I agree weak TS at worst case. Ppl this week been calling for cat 3 tho consistently... REALLY??? I've been lurking everyday and have not seen ANYONE saying anything about 96l becoming a cat3?? You sure your reading the correct blog.. or maybe your just making stuff up for the sake of the argument?

1218. hurricaster 22:42 GMT le 07 juillet 2010
Awesome. Should be something to see. Member Since: 22 juillet 2008 Posts: 0 Comments: 109

1219. Houstonia 22:43 GMT le 07 juillet 2010
Statement as of 5:39 PM CDT on July 07, 2010 The National Weather Service in League City has issued an * Urban and Small Stream Flood Advisory for... central Harris County in southeast Texas... * until 645 PM CDT * at 538 PM CDT... National Weather Service Doppler radar indicated very heavy rain was falling in and around the city of Houston. Flooded roadways have been reported in the Bellaire area and in The Heights as of 530 PM CDT. Precautionary/preparedness actions... Excessive runoff from heavy rainfall may cause elevated water levels on small creeks... streams... and bayous. Additionally... ponding of water will occur on highways... streets... and underpasses as well as other poor drainage areas and low lying areas. A Flood Watch remains in effect through 7pm Thursday for the warned area. Please report flooding to the County sheriff... local police... or department of public safety and ask them to relay your report to the National Weather Service. Lat... Lon 2965 9556 3010 9573 3010 9567 3011 9565 3014 9550 3011 9549 3011 9543 3009 9539 3007 9534 3003 9529 3005 9525 3012 9516 2974 9503 Member Since: 20 mai 2003 Posts: 0 Comments: 71

1220. TexasHurricane 22:43 GMT le 07 juillet 2010
Quoting StormW: Got some overshooting tops going up. meaning it is developing? Member Since: 2 juillet 2009 Posts: 0 Comments: 2811

1221. hurricaster 22:44 GMT le 07 juillet 2010
Is there such thing as a goofcaster? Seem to have a few in our midst. Member Since: 22 juillet 2008 Posts: 0 Comments: 109

1223. TxMarc71 22:45 GMT le 07 juillet 2010
Quoting TexasHurricane: meaning it is developing? Higher the cloud tops are the more severe the storm is.... thus the more potential for development...

1224. txwxnut2 22:45 GMT le 07 juillet 2010
I'm seeing low level inflow, circulation on visible. Right now in Corpus Christi, the pressure is 29.82 North East Winds @ 28 gusting to 40 with a squal that just came through. The winds have been out of the northeast since noon. I think we have a surface low at this point, especially given our pressure - 1009.7mb Member Since: 26 août 2006 Posts: 0 Comments: 68

1225. TexasHurricane 22:47 GMT le 07 juillet 2010
Quoting StormW: Yes...in fact, IR2 loop imagery indicates the LLC is pretty much under the convection...96L is becoming increasingly vertically stacked. oh ok. So what do you think this will become? If it does get a little stronger can it go a little furthur north? Member Since: 2 juillet 2009 Posts: 0 Comments: 2811

1226. MiamiHurricanes09 22:47 GMT le 07 juillet 2010
Quoting StormW: Yes...in fact, IR2 loop imagery indicates the LLC is pretty much under the convection...96L is becoming increasingly vertically stacked. That's even more reason to upgrade the percentage at 8PM. Member Since: 2 septembre 2009 Posts: 129 Comments: 20003

1227. KoritheMan 22:47 GMT le 07 juillet 2010
Quoting hurricaster: Awesome. Should be something to see. Better get those fish shower curtains ready. Member Since: 7 Mars 2007 Posts: 421 Comments: 15643

1228. TexasHurricane 22:47 GMT le 07 juillet 2010
Quoting TxMarc71: Higher the cloud tops are the more severe the storm is.... thus the more potential for development... Thanks... Member Since: 2 juillet 2009 Posts: 0 Comments: 2811

1231. TxMarc71 22:48 GMT le 07 juillet 2010
Heavy topical rain here in Houston for the last couple hours.. almost no thunder and lightning.. very little wind .. just flat out heavy tropical rain

1232. Daveg 22:48 GMT le 07 juillet 2010
Quoting TexasHurricane: oh ok. So what do you think this will become? If it does get a little stronger can it go a little furthur north? Personally, I think at best a TS....going in somewhere around or just south of Corpus Christi. Then again, these storms never cease to amaze and surprise me. Member Since: 23 septembre 2005 Posts: 0 Comments: 426

1234. Patrap 22:50 GMT le 07 juillet 2010
Member Since: 3 juillet 2005 Posts: 377 Comments: 112973

1235. KEEPEROFTHEGATE (Mod) 22:50 GMT le 07 juillet 2010
Member Since: 15 juillet 2006 Posts: 147 Comments: 41332

1236. MiamiHurricanes09 22:50 GMT le 07 juillet 2010
Quoting StormW: Upper level anticyclone now over 96L Impressive. Member Since: 2 septembre 2009 Posts: 129 Comments: 20003

1237. Patrap 22:50 GMT le 07 juillet 2010
Member Since: 3 juillet 2005 Posts: 377 Comments: 112973

1238. KEEPEROFTHEGATE (Mod) 22:51 GMT le 07 juillet 2010
ALERT ATCF MIL 96X XXX 100707180000 2010070718 23.8 266.4 26.1 261.2 100 23.8 266.4 072100 1007072000 2 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.// 9610070306 159N 760W 25 9610070312 162N 775W 25 9610070318 150N 799W 25 9610070400 154N 808W 25 9610070406 157N 816W 25 9610070412 160N 822W 30 9610070418 164N 826W 30 9610070500 168N 831W 30 9610070506 174N 837W 30 9610070512 182N 846W 30 9610070518 188N 853W 30 9610070600 197N 868W 30 9610070606 205N 881W 30 9610070612 213N 895W 30 9610070618 220N 907W 25 9610070700 224N 916W 25 9610070706 228N 924W 25 9610070712 232N 930W 25 9610070718 238N 936W 30 Member Since: 15 juillet 2006 Posts: 147 Comments: 41332

1239. Patrap 22:52 GMT le 07 juillet 2010
Gulf Of Mexico - Water Vapor Loop Member Since: 3 juillet 2005 Posts: 377 Comments: 112973

1240. MiamiHurricanes09 22:52 GMT le 07 juillet 2010
What percentage will the NHC give 96L of tropical cyclone formation in the next 48 hours on the 8PM TWO? The person that guesses correctly gets a cookie. Lol. By the way I went with a 70% chance. Member Since: 2 septembre 2009 Posts: 129 Comments: 20003

1241. CybrTeddy 22:54 GMT le 07 juillet 2010
I'll be conservative and say 60%. Member Since: 8 juillet 2005 Posts: 255 Comments: 20633

1242. oakland 22:55 GMT le 07 juillet 2010
Keeper- Where is that data from? Member Since: 4 septembre 2005 Posts: 41 Comments: 7520

1243. KarenRei 22:55 GMT le 07 juillet 2010
Oy -- does every storm this year have to try to spin up the entire Gulf? :P Member Since: 7 septembre 2007 Posts: 1 Comments: 934

1244. Patrap 22:55 GMT le 07 juillet 2010
Member Since: 3 juillet 2005 Posts: 377 Comments: 112973

1246. OneDay 22:56 GMT le 07 juillet 2010
Quoting Patrap: Gulf Of Mexico - Water Vapor Loop So much for the dry air in the W GOM... Member Since: 13 juillet 2005 Posts: 35 Comments: 930

1247. HurricaneSwirl 22:56 GMT le 07 juillet 2010
Quoting MiamiHurricanes09: What percentage will the NHC give 96L of tropical cyclone formation in the next 48 hours on the 8PM TWO? The person that guesses correctly gets a cookie. By the way I went with a 70% chance. 60% chance. That cookie will be MINE! Although 70% chance is what it SHOULD be. Member Since: 7 juillet 2008 Posts: 2 Comments: 3237

1248. Hurricanes101 22:56 GMT le 07 juillet 2010
I will say 73% chance oh wait they don't break it down that far yet? oh right that will be next season lol I am on the fence, I guess it depends on how well organized they see it, I could see them going anywhere from 60-80%, but if I had to guess I would say 60% Member Since: 10 Mars 2010 Posts: 1 Comments: 6930

1249. CJC111 22:57 GMT le 07 juillet 2010
Hi Storm, does the tropical funnle come with a small umbrella?

1250. OracleDeAtlantis 22:57 GMT le 07 juillet 2010
"The usually dry Santa Catarina river that runs through the centre of Monterrey turned into a raging torrent, flooding major highways and paralysing Mexico's third-biggest city." Member Since: 27 août 2009 Posts: 0 Comments: 323

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