ATL: CHRIS - Post-Tropical

[TropicalAnalystwx13]

I do not usually disagree with the National Hurricane Center, but this is one of those rare cases. Infrared imagery reveals that TS Chris is obviously not a 60 mph. In fact, it's likely pushing hurricane status. Convection has been further wrapping around the eye and deepening with time. I guess we'll see what happens at 5AM EDT, but it'll probably be weakening by that time.

This is probably a post-season analysis case.

[ozonepete]

Yeah, it certainly has been surprising how it keeps improving its core convective circulation over surface temps like that. I wonder if the SSTs there may be underestimated a little, since it appears to still be very tropical and doesn't appear that the convection is due to baroclinic causes.

[SouthDadeFish]

I think the case for Chris being a hurricane can be made. Satellite presentation only continues to improve:



Reminds me of Epsilon in 2005. Keeps strengthening unexpectedly.

[Cainer]

I'd say even without the winds mixing fully to the surface, Chris is flirting with hurricane intensity. Convection is still deepening and wrapping around the center along with the eye becoming warmer. If it keeps it up till the 5 AM advisory, I'd say there's a decent chance the NHC will upgrade. If not, wouldn't surprise me to see it looked at in the post-season review.

My posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Zanthe]

Lots and lots and lots of work to do in the post season.

[DanieleItalyRm]

Very interesting CHRIS. It moves on water of 22 °C. It had a tropical transition process (extratropical->subtropical->tropical) the same process that produced many tropical cyclones over Mediterranean Sea (and Karl, Vince, Epsilon, Grace ecc).


CHRIS 50 Kt:


But 'even the recent Invest 92L May 2012 was a clear tropical storm (deserved at least subtropical), although very small; it occurred under conditions similar to CHRIS...

[brunota2003]

When was the last time anyone saw a 50 knot tropical storm that had a fully formed eye for over 12 hours?

And of course...ADT keeps going with a curved band scene type, and keeps putting the center marker well to the west of the eye (going off of forecast interpretation)...

[cycloneye]

TROPICAL STORM CHRIS DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032012
500 AM AST THU JUN 21 2012

CHRIS HAS MAINTAINED AN EYE-LIKE FEATURE SURROUNDED BY A RING OF
CONVECTION WITH CLOUD TOP TEMPERATURES OF -50C TO -60C DURING THE
PAST FEW HOURS. SUBJECTIVE AND OBJECTIVE DVORAK T-NUMBERS ARE
ESSENTIALLY UNCHANGED SINCE THE LAST ADVISORY AND DO NOT SUPPORT A
HIGHER INTENSITY...SO THE INITIAL INTENSITY IS KEPT AT 50 KT. EVEN
IF CHRIS IS STRONGER THAN ESTIMATED...THE PASSAGE OF THE CYCLONE
OVER SUB-22C SEA SURFACE TEMPERATURES COULD BE INHIBITING AN
EFFICIENT CONVECTIVE TRANSPORT OF THE STRONGEST WINDS TO THE
OCEAN SURFACE.

THE INITIAL MOTION IS 065/17...WHICH IS A BIT SLOWER AND TO THE LEFT
OF THE PREVIOUS ESTIMATE. CHRIS IS EXPECTED TO TURN NORTH-
NORTHEASTWARD AND THEN NORTHWARD AS IT DECELERATES AND DUMBBELLS
CYCLONICALLY AROUND A LARGE MID- TO UPPER-LEVEL LOW FORECAST TO CUT
OFF SOUTHEAST OF THE CANADIAN MARITIME PROVINCES DURING THE NEXT
24-36 HOURS. MODEL GUIDANCE GENERALLY SHOWS CHRIS BEING ABSORBED BY
THIS WEATHER FEATURE IN 36-48 HOURS...WITH THE NEW ENTITY
COMPLETING A CYCLONIC LOOP AND THEN MOVING EASTWARD TO EAST-
NORTHEASTWARD OVER THE FAR NORTH ATLANTIC. GLOBAL MODELS ARE IN
GOOD AGREEMENT WITH REGARD TO THIS SCENARIO...AND THE TRACK
FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE.

DESPITE THE FACT THAT CHRIS IS MOVING OVER RATHER COOL WATERS...
A 0505 UTC AMSU PASSES STILL SHOWED THE PRESENCE OF A WELL-DEFINED
MODERATE TO DEEP WARM CORE IN ASSOCIATION WITH THE CYCLONE.
ALTHOUGH CHRIS IS EXPECTED TO MAINTAIN WARM-CORE CHARACTERISTICS
DURING THE NEXT 24 HOURS OR SO...IT COULD LOSE ITS DEEP CONVECTION
WHILE MOVING OVER EVEN COOLER WATERS AND BE DECLARED POST-TROPICAL.
SHOULD IT MAINTAIN DEEP CONVECTION LONGER...EITHER ITS INTERACTION
WITH A LOW-LEVEL BAROCLINIC ZONE TO THE NORTH AND/OR ITS
INTERACTION WITH THE CUT-OFF LOW TO ITS WEST SHOULD RESULT IN
EXTRATROPICAL TRANSITION IN ABOUT 36 HOURS.


FORECAST POSITIONS AND MAX WINDS

INIT 21/0900Z 39.9N 44.8W 50 KT 60 MPH
12H 21/1800Z 41.6N 43.1W 50 KT 60 MPH
24H 22/0600Z 43.6N 43.0W 50 KT 60 MPH...POST-TROPICAL
36H 22/1800Z 44.3N 44.8W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 23/0600Z 43.0N 46.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 24/0600Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW

$$
FORECASTER KIMBERLAIN

[cycloneye]

Hurricane Chris on 12z Best Track

AL, 03, 2012062112, , BEST, 0, 405N, 439W, 65, 987, HU

http://ftp.nhc.noaa.gov/atcf/tcweb/inve ... 012.invest

[Aric Dunn]

about time. must of been some ship report. because the discussion really sounded like they were not going to upgrade.

[RL3AO]

about time. must of been some ship report. because the discussion really sounded like they were not going to upgrade.

Couldn't find it with an NDBC search. Wonder what it is?

[RL3AO]

BT has changed.

55kt at 0z
60kt at 6z
65kt at 12z

[northjaxpro]

Amazing that the first designated cane of the season developed that far north in the Atlantic. Also, I can't wait to see the post-season analysis from NHC. I still think there is a possibility Beryl will be classified as a minimal hurricane as well.

[ozonepete]

When was the last time anyone saw a 50 knot tropical storm that had a fully formed eye for over 12 hours?

And of course...ADT keeps going with a curved band scene type, and keeps putting the center marker well to the west of the eye (going off of forecast interpretation)...

Very good point my friend. I was wondering why their numbers were so low but didn't get a chance to look at the analysis until now. Wonder if they realized what was going on and that had something to do with the upgrade as well...

[HurrMark]

Awww...too bad...I was hoping we could make a run for beating last year's record of the msot tropical storms without a hurricane (If Debby forms in the Gulf, in my opinion...not official...I don't think it will be a hurricane). But yeah, it looks stronger than 60 mph...like an Epsilon or other late season storms.

[ozonepete]

Really nice presentation on satellite. And it made hurricane just in the nick of time. You can't believe it will be able to hang onto such a good convective core for much longer given those water temps.

[Zanthe]

What a weird hurricane. But it looks like it would be hard to argue about it. A nice outflow band to the north, deep convection encircling a beautiful eye, and for a system north of 40 degrees. Just wow.

[ozonepete]

When was the last time anyone saw a 50 knot tropical storm that had a fully formed eye for over 12 hours?

And of course...ADT keeps going with a curved band scene type, and keeps putting the center marker well to the west of the eye (going off of forecast interpretation)...

Very good point my friend. I was wondering why their numbers were so low but didn't get a chance to look at the analysis until now. Wonder if they realized what was going on and that had something to do with the upgrade as well...

And there you go: CIMSS just changed the positioning method to RING/SPIRAL COMBINATION and - BINGO! - the program has found the center! Notice how the raw T# jumped to 4.5 from a 3. Shows how important the initialization type is.

[hurricaneCW]

Chris looks better than many storms existing in the deep tropics.

[brunota2003]

4.5 is close to 75 knots, right? I could see them going with 70 knots with that presentation.