Official Hurricane Irene Live OBS/Discussion Part II

[winterwarlock]

going to try and fit in to cut some lawns tomorrow morning...any chance the steady showers dont develop until after the noon hour? Whats the timeline here...thanks

[pazzo83]

from twitter

NOAA42: Flight level winds have picked up a bit, we're about 80 nm N of center

Seems to be reorganizing a bit, colder cloud tops. Makes sense given its location. Perhaps it will bump up 5-10mph. I don't think that will really matter for us, as this probably will take a while to weaken as it moves northward past NC unless it goes well west over land.

[RCNYILWX]

I think something that hasn't been mentioned enough is that the guidance is suggesting an extratropical transition (ET) with Irene as it makes to the vicinity of nyc/li. http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_850_048l.gif

On this plot from 18z gfs, you can see that by that point, cool advection is starting at 850 mb as the strong upper trough deepens over the region, so clearly the system will be becoming baroclinic. You can probably infer that that process might be getting started between hour 42 and hour 48. An extratropical transition might be a bad thing in this case because it'll lead to a further expansion of the already huge wind field and also even the western side of the storm is liable to get strong gusts mixing down. In my synoptic meteorology class at Stony Brook I learned that the 1938 hurricane was likely undergoing explosive ET when it made landfall on LI. Some storms weaken quickly when they start to lose tropical characteristics, but some maintain or even strengthen a bit when they become hybrid or baroclinic. Being in the right entrance region of the strengthening 250 mb jet streak consistently progged over the northeast as Irene moves north might also aid in this process. The sometimes explosive ET is why there's been several examples, most notably Hurricane Igor last summer, of hurricanes that have done very significant damage to the Atlantic Provinces of Canada. I hope I'm wrong, but I think that Irene will have a significant impact on the metro region and that trying to downplay it is a big mistake at this point.

[gkrangers]

Steve d thinking possible RI can occur

Just like winter.

[CooL]

Seems to be reorganizing a bit, colder cloud tops. Makes sense given its location. Perhaps it will bump up 5-10mph. I don't think that will really matter for us, as this probably will take a while to weaken as it moves northward past NC unless it goes well west over land.

agree fully.

btw, check out the shear size of this storm. Its about to engulf the whole east coast

http://www.ssd.noaa.gov/goes/east/eaus/flash-rb.html

[viking70]

lmao Tropical Storm Warnings for NW NJ and Hudson Valley now.

Hurricane Warning for Southern and Northern Westchester!!

[KEITH L.I]

I think something that hasn't been mentioned enough is that the guidance is suggesting an extratropical transition (ET) with Irene as it makes to the vicinity of nyc/li. http://www.nco.ncep....fs_850_048l.gif

On this plot from 18z gfs, you can see that by that point, cool advection is starting at 850 mb as the strong upper trough deepens over the region, so clearly the system will be becoming baroclinic. You can probably infer that that process might be getting started between hour 42 and hour 48. An extratropical transition might be a bad thing in this case because it'll lead to a further expansion of the already huge wind field and also even the western side of the storm is liable to get strong gusts mixing down. In my synoptic meteorology class at Stony Brook I learned that the 1938 hurricane was likely undergoing explosive ET when it made landfall on LI. Some storms weaken quickly when they start to lose tropical characteristics, but some maintain or even strengthen a bit when they become hybrid or baroclinic. Being in the right entrance region of the strengthening 250 mb jet streak consistently progged over the northeast as Irene moves north might also aid in this process. The sometimes explosive ET is why there's been several examples, most notably Hurricane Igor last summer, of hurricanes that have done very significant damage to the Atlantic Provinces of Canada. I hope I'm wrong, but I think that Irene will have a significant impact on the metro region and that trying to downplay it is a big mistake at this point.

Best post of the day!..totally agree

[pazzo83]

SLOSH modeling showing the areas of storm surge potential

The geography of the NY harbor presents a rather frightening scenario for a direct hit like this, especially if we get hurricane force+ winds pushing water into the harbor.

[pazzo83]

I think something that hasn't been mentioned enough is that the guidance is suggesting an extratropical transition (ET) with Irene as it makes to the vicinity of nyc/li. http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_850_048l.gif

On this plot from 18z gfs, you can see that by that point, cool advection is starting at 850 mb as the strong upper trough deepens over the region, so clearly the system will be becoming baroclinic. You can probably infer that that process might be getting started between hour 42 and hour 48. An extratropical transition might be a bad thing in this case because it'll lead to a further expansion of the already huge wind field and also even the western side of the storm is liable to get strong gusts mixing down. In my synoptic meteorology class at Stony Brook I learned that the 1938 hurricane was likely undergoing explosive ET when it made landfall on LI. Some storms weaken quickly when they start to lose tropical characteristics, but some maintain or even strengthen a bit when they become hybrid or baroclinic. Being in the right entrance region of the strengthening 250 mb jet streak consistently progged over the northeast as Irene moves north might also aid in this process. The sometimes explosive ET is why there's been several examples, most notably Hurricane Igor last summer, of hurricanes that have done very significant damage to the Atlantic Provinces of Canada. I hope I'm wrong, but I think that Irene will have a significant impact on the metro region and that trying to downplay it is a big mistake at this point.

Very interesting and makes a lot of sense. Perhaps this explains some of the pressure drops that were being seen on the models as the storm moved away from the Delmarva.

[CooL]

http://www.weatheroffice.gc.ca/model_forecast/animateweb_e.html?imagetype=model_forecast&imagename=18_054_R1_north@america_I_4PAN_CLASSIC@012_....jpg

RGEM.. Very scary track, basically due north right into the city

[Thunderdude]

I think something that hasn't been mentioned enough is that the guidance is suggesting an extratropical transition (ET) with Irene as it makes to the vicinity of nyc/li. http://www.nco.ncep....fs_850_048l.gif

On this plot from 18z gfs, you can see that by that point, cool advection is starting at 850 mb as the strong upper trough deepens over the region, so clearly the system will be becoming baroclinic. You can probably infer that that process might be getting started between hour 42 and hour 48. An extratropical transition might be a bad thing in this case because it'll lead to a further expansion of the already huge wind field and also even the western side of the storm is liable to get strong gusts mixing down. In my synoptic meteorology class at Stony Brook I learned that the 1938 hurricane was likely undergoing explosive ET when it made landfall on LI. Some storms weaken quickly when they start to lose tropical characteristics, but some maintain or even strengthen a bit when they become hybrid or baroclinic. Being in the right entrance region of the strengthening 250 mb jet streak consistently progged over the northeast as Irene moves north might also aid in this process. The sometimes explosive ET is why there's been several examples, most notably Hurricane Igor last summer, of hurricanes that have done very significant damage to the Atlantic Provinces of Canada. I hope I'm wrong, but I think that Irene will have a significant impact on the metro region and that trying to downplay it is a big mistake at this point.

If that is case will this then if this true will then be consider a noreaster for us instead of a tropical storm or hurricane?

[earthlight]

[psv88]

goosebumps.

[RCNYILWX]

Very interesting and makes a lot of sense. Perhaps this explains some of the pressure drops that were being seen on the models as the storm moved away from the Delmarva.

Agreed, and again, I hope I'm wrong, but it's possible that by landfall, Irene will be a massive hybrid part warm core part baroclinic cyclone. Like a massive noreaster with strong tropical storm or hurricane strength sustained with higher gusts instead of lower end tropical storm force winds and higher gusts (12/92 and 3/10 being more extreme examples). The cool advection is a worry because cooler temperatures aloft will lead to steepening lapse rates and destabilize the profile, possibly enhancing downward momentum transfer of stronger winds aloft, especially in convection around the cyclone. A really interesting read is the Wikipedia entry on Igor: http://en.wikipedia.org/wiki/Hurricane_Igor. Its winds actually increased from 75 mph to 85 mph by the time it made landfall over Newfoundland and tropical storm force winds had a 340 mile radius, even larger than Irene's current 290. Not saying that exact thing is going to happen, but an example of what can happen when a tropical cyclone undergoes ET. The upper trough diving in on Saturday and Sunday is a worrying thing for the potential an ET of Irene might hold.

[nycsnow]

The Port Authority will close John F. Kennedy International Airport to incoming international flights beginning at noon tomorrow

Seesmic • 8/26/11 7:04 PM

[RCNYILWX]

If that is case will this then if this true will then be consider a noreaster for us instead of a tropical storm or hurricane?

If it actually happens, it'll still have some warm core left and if the winds are still strong TS or hurricane strength, NHC will not downgrade from a hurricane or TS because it'll give the public the wrong impression that the situation is less serious. But technically, which was the case with Igor in the other post I made, the storm would be a very powerful hybrid warm core/mid-latitude cyclone. Igor had almost completely become baroclinic when it made landfall, but it was still classified as a hurricane to not confuse things. And it's impacts were indeed extreme for Newfoundland.

[IsentropicLift]

big improvements from a few hours ago

[wkd]

If it actually happens, it'll still have some warm core left and if the winds are still strong TS or hurricane strength, NHC will not downgrade from a hurricane or TS because it'll give the public the wrong impression that the situation is less serious. But technically, which was the case with Igor in the other post I made, the storm would be a very powerful hybrid warm core/mid-latitude cyclone. Igor had almost completely become baroclinic when it made landfall, but it was still classified as a hurricane to not confuse things. And it's impacts were indeed extreme for Newfoundland.

I may have missed your previous posts but the last few have been excelent. Hope to get a lot more of your input

[Thunderdude]

If it actually happens, it'll still have some warm core left and if the winds are still strong TS or hurricane strength, NHC will not downgrade from a hurricane or TS because it'll give the public the wrong impression that the situation is less serious. But technically, which was the case with Igor in the other post I made, the storm would be a very powerful hybrid warm core/mid-latitude cyclone. Igor had almost completely become baroclinic when it made landfall, but it was still classified as a hurricane to not confuse things. And it's impacts were indeed extreme for Newfoundland.

So this even it is undergoes its ET transition will be really a noreaster will it makes landfall from NYC to LI? When I think of coastal ET system I think noreaster. What will be the difference between this storm and regular noreaster?

[A-L-E-X]

Agreed, and again, I hope I'm wrong, but it's possible that by landfall, Irene will be a massive hybrid part warm core part baroclinic cyclone. Like a massive noreaster with strong tropical storm or hurricane strength sustained with higher gusts instead of lower end tropical storm force winds and higher gusts (12/92 and 3/10 being more extreme examples). The cool advection is a worry because cooler temperatures aloft will lead to steepening lapse rates and destabilize the profile, possibly enhancing downward momentum transfer of stronger winds aloft, especially in convection around the cyclone. A really interesting read is the Wikipedia entry on Igor: http://en.wikipedia..../Hurricane_Igor. Its winds actually increased from 75 mph to 85 mph by the time it made landfall over Newfoundland and tropical storm force winds had a 340 mile radius, even larger than Irene's current 290. Not saying that exact thing is going to happen, but an example of what can happen when a tropical cyclone undergoes ET. The upper trough diving in on Saturday and Sunday is a worrying thing for the potential an ET of Irene might hold.

Excellent points and it sounds like those storms you often see in the middle of the Atlantic that were once hurricanes. They are often bigger and more dangerous then when they were hurricanes.

[RCNYILWX]

I may have missed your previous posts but the last few have been excelent. Hope to get a lot more of your input

Thanks! I'll probably chime in here and there over the next few days. I'm from Queens, but I live in Illinois, Met Intern at WFO Chicago. My family is still there, so I'm very concerned with Irene. It'll be interesting to see how this works out, the interaction with the strong 250 mb jet expected to form over the northeast, and the other stuff I wrote about. I hope Irene takes the farther inland track and weakens enough before any ET to reduce the tree damage and power outage potential, but the fresh water and coastal flooding is probably still going to be major.

[earthlight]

Amazing differences in timing for a 42 hour forecast. The GFS at 42 hours has the center of the storm a few miles off Long Beach Island...while the NAM is still east of Ocean City, MD.

[cut]

I remember Frank Strait talking about difluence (sp?) at 200 millibars. Perhaps this is also playing a roll?

Agreed, and again, I hope I'm wrong, but it's possible that by landfall, Irene will be a massive hybrid part warm core part baroclinic cyclone. Like a massive noreaster with strong tropical storm or hurricane strength sustained with higher gusts instead of lower end tropical storm force winds and higher gusts (12/92 and 3/10 being more extreme examples). The cool advection is a worry because cooler temperatures aloft will lead to steepening lapse rates and destabilize the profile, possibly enhancing downward momentum transfer of stronger winds aloft, especially in convection around the cyclone. A really interesting read is the Wikipedia entry on Igor: http://en.wikipedia..../Hurricane_Igor. Its winds actually increased from 75 mph to 85 mph by the time it made landfall over Newfoundland and tropical storm force winds had a 340 mile radius, even larger than Irene's current 290. Not saying that exact thing is going to happen, but an example of what can happen when a tropical cyclone undergoes ET. The upper trough diving in on Saturday and Sunday is a worrying thing for the potential an ET of Irene might hold.

[RCNYILWX]

So this even it is undergoes its ET transition will be really a noreaster will it makes landfall from NYC to LI? When I think of coastal ET system I think noreaster. What will be the difference between this storm and regular noreaster?

I still think it'll have tropical characteristics, so if the guidance is right it'll probably be hybrid tropical/extratropical at or shortly after landfall, but if it were to actually complete ET, it would technically be an extremely strong and large mid-latitude cyclone or noreaster, yes. But the NHC won't classify it as extratropical until it's well to the north of the US likely even if that were to occur because the impacts will still be ongoing.

[salbers]

Regarding the evacuation zones on Long Island, I think they cover areas below 10 feet elevation. This sounds reasonably prudent.

[earthlight]

[riverrat]

This is not good for the Passaic River basin.

[A-L-E-X]

Regarding the evacuation zones on Long Island, I think they cover areas below 10 feet elevation. This sounds reasonably prudent.

Perhaps east of Rockville Centre, but Im in a Cat 4 zone and my elevation is 17 feet. I'm a few miles south of Sunrise Hwy. They were probably keeping it simple not to confuse the public though-- their surge maps are rather inaccurate with the labeling and I had to have a second map handy to figure out exactly what surge zone I am in. It would have been better if one could just input an address and get the info.

[RCNYILWX]

I remember Frank Strait talking about difluence (sp?) at 200 millibars. Perhaps this is also playing a roll?

That diffluence or upper level divergence may first aid in maintaining Irene's intensity for longer farther north over cooler waters (should it remain over water during that time) by enhancing the northern outflow and also Irene will be sitting in the right entrance region of that jet, a favored region for enhanced upward motion. The enhanced upward motion would mean a stronger system and also explain the extreme rainfall amounts being progged universally by the models. Then as the jet intensifies a s the UL trough deepens over the Northeast, the favorable jet structure may lead or contribute to a strong hybrid or ET cyclone if I'm correct about this ET stuff. A transition would also up the ante for wind damage across large swaths of the interior Northeast (especially higher elevations) as well because baroclinic processes would favor the very strong winds aloft being mixed down in all quadrants of the cyclone away from the center.

[RCNYILWX]

This is not good for the Passaic River basin.

And all the deciduous trees around the area.