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Tropical Storm Chris


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Any doubts I had about Chris being a TC have been erased. MIMIC-TPW and even the geostationary satellites show it completely separated from the frontal system. Convection is wrapped 3/4 of the way around the center and has persisted for almost 24 hours. It's even down to 38 degrees latitude.

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Chris should be upped to 60mph at 5pm

AL, 03, 2012062018, , BEST, 0, 382N, 502W, 50, 997, TS, 50, NEQ, 0, 30, 0, 0, 1012, 250, 30, 55, 0, L, 0, , 0, 0, CHRIS, M, 12, NEQ, 90, 140, 220, 60

a few hours of decent environment and ssts are left

post-29-0-99369700-1340224511_thumb.jpg

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The intensification of Chris over the past 24 hours is quite impressive considering how cool the waters are, and is just another example of how cool waters and high latitudes don't necessarily limit tropical cyclones, there are other factors. I think the northerly outflow jet of Chris is key right now, it appears to be coupled with a mid-latitude jet stream and is evacuating quite a bit of mass from the center, and thus leading to intensification. Read more on my blog http://weather.schematical.com/

post-645-0-46733200-1340227818_thumb.jpg

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From the AOML TC FAQ. The key point the NHC uses for classication is how tight the RMW is/how tight the convective bands are. Of course that's up for debate and I think we need a new classification system that's more natural.

http://www.aoml.noaa...d/tcfaq/A6.html

A sub-tropical cyclone is a low-pressure system existing in the tropical or subtropical latitudes (anywhere from the equator to about 50°N) that has characteristics of both tropical cyclones and mid-latitude (or extratropical) cyclones. Therefore, many of these cyclones exist in a weak to moderate horizontal temperature gradient region (like mid-latitude cyclones), but also receive much of their energy from convective clouds (like tropical cyclones). Often, these storms have a radius of maximum winds which is farther out (on the order of 100-200 km [60-125 miles] from the center) than what is observed for purely "tropical" systems. Additionally, the maximum sustained winds for sub-tropical cyclones have not been observed to be stronger than about 33 m/s (64 kts, 74 mph)).

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We will see how long it can hang on to that eye signature, but it looks pretty nice right now. If it could stay like this for 6-12 hours, an argument could be made for upgrading it to a hurricane.

192ijt.jpg

Yeah the NHC saying it had peaked at the 5pm is probably what gave the storm the extra boost it needs. It looks similar to beryl, but with the quick motion it may have stronger winds.

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I must be the only person on here that doesn't understand why so many are "disappointed" or "upset" when the NHC names systems like this.

I've asked NHC to up the TS threashold to at least 60mph after last year .They ignored me so it's not happening unfortunately but it was worth a shot.

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The definition of TS comes from the Beaufort scale, Gale = 39 mph = TS. It would be logical to change the definiton of a TS to a "storm" or 55 mph.

The direction of the science is in the opposite direction. I believe they are now testing track ad intensity forecasts for invests now, although of course the defintions would not be changed, it acknowledges that a rapidly developing invest near land poses a threat.

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We will see how long it can hang on to that eye signature, but it looks pretty nice right now. If it could stay like this for 6-12 hours, an argument could be made for upgrading it to a hurricane.

That northern outflow channel is really "supercharging" Chris, but I think it's pretty much beginning extratropical transition as well which isn't really conducive for maintaining a tropical cyclone-like inner core. Still might attain hurricane force winds when extratropical transition peaks.

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If the current convection wraps around the southeast side of the eye, I'd say it's a Hurricane. NHC probably won't admit it until post analysis though. The small core and fast movement are giving it a little wind speed boost.

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I think we will see upgrade at 11am... its maintained the eye feature for a full 12 hours now, and the convection surrounding the core has only grown stronger. Microwave indicates the convection is now nearly wrapping around the center. I'm a little perplexed the satellite estimates haven't gotten higher, but ADT seems to have not switched into an embedded eye pattern which is causing the T# to suffer. SATCON has been dancing around 55-60 knots which may be closer to the real intensity. Certainly didn't expect this satellite presentation when I woke up.

2v30pqq.jpg

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Pretty impressive sat image this morning. Got to be one of the best look 60mph TS with an eye i've ever seen.

The cool SSTs/low near surface instabilty/not mxing winds down effectively from NHC seems to me like a good argument not to assume an eye means a hurricane.

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:lmao:

AL, 03, 2012062112, , BEST, 0, 405N, 439W, 65, 987, HU, 34, NEQ, 60, 90, 70, 50, 1008, 180, 20, 0, 0, L, 0, , 0, 0, CHRIS, M,

AL, 03, 2012062112, , BEST, 0, 405N, 439W, 65, 987, HU, 50, NEQ, 40, 40, 40, 30, 1008, 180, 20, 0, 0, L, 0, , 0, 0, CHRIS, M,

AL, 03, 2012062112, , BEST, 0, 405N, 439W, 65, 987, HU, 64, NEQ, 20, 20, 0, 0, 1008, 180, 20, 0, 0, L, 0, , 0, 0, CHRIS, M,

201206210946windsatWINDSAT_NRL_6GHz_VISwind03LCHRIS3993_084pc_50kts-995mb_394N_456W_sft20120621_0600.jpg

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There have been other "cold SST" hurricanes, like Vince and Epsilon in 2005

Yep I immediately thought of those. Both were late season though. Vince probably is more unusual than Chris. 2007 Humberto was also a big surprise but is a completely different case.

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There have been other "cold SST" hurricanes, like Vince and Epsilon in 2005

I was just gonna say this pulled an Epsilon on the NHC/every other forecaster. Amazing this can happen over 25 °C water. As I've been harping on I think the answer lies in the coupling of Chris' outflow with a mid-latitude jetstream, as can be seen in the below chart. I wrote more about it on my blog http://weather.schematical.com/

post-645-0-97026000-1340288755_thumb.png

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