ATL: DORIAN - Post-Tropical - Discussion

[KWT]

The drier air is pretty obvious in that Sat.imagery, you can see the Cirrus deck starting to become embedded into the western side of the circulation. However from now on, the system will be getting ever warming waters to help it try and overcome the dry air.

[tolakram]

14:15Z

[cycloneye]

BULLETIN
TROPICAL STORM DORIAN ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
1100 AM AST THU JUL 25 2013

...DORIAN MOVING WEST-NORTHWESTWARD OVER THE CENTRAL TROPICAL
ATLANTIC WITH NO CHANGE IN STRENGTH...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.0N 35.9W
ABOUT 1800 MI...2900 KM E OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 AM AST...1500 UTC...THE CENTER OF TROPICAL STORM DORIAN WAS
LOCATED NEAR LATITUDE 16.0 NORTH...LONGITUDE 35.9 WEST. DORIAN IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 17 MPH...28 KM/H. HIS GENERAL
MOTION IS EXPECTED TO CONTINUE TODAY...FOLLOWED BY A GRADUAL TURN
TOWARD THE WEST ON FRIDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 60 MPH...95 KM/H...WITH HIGHER
GUSTS. SOME FLUCTUATIONS IN STRENGTH ARE LIKELY DURING THE NEXT
48 HOURS.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB...29.50 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 PM AST.

$$
FORECASTER STEWART


TROPICAL STORM DORIAN DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
1100 AM AST THU JUL 25 2013

CONVENTIONAL AND MICROWAVE SATELLITE IMAGERY INDICATE THAT THERE HAS
BEEN NO SIGNIFICANT CHANGE IN THE OVERALL CONVECTIVE PATTERN OR
STRUCTURE OF DORIAN SINCE THE PREVIOUS ADVISORY. THE COMPACT
TROPICAL CYCLONE HAS MAINTAINED A SMALL BUT SYMMETRIC OUTFLOW
PATTERN...ALONG WITH GOOD LOW-LEVEL EQUATORIAL INFLOW. SATELLITE
INTENSITY ESTIMATES ARE 55 KT FROM TAFB AND AND 45 KT FROM TAFB...
SO THE INITIAL INTENSITY IS BEING MAINTAINED AT 50 KT. THE INITIAL
POSITION IS A LITTLE SOUTH OF THE CONVENTIONAL SATELLITE FIX
POSITIONS BASED ON MICROWAVE IMAGERY OVER THE PAST 6 HOURS.

THE INITIAL MOTION ESTIMATE IS 285/15. THERE IS ESSENTIALLY NO
CHANGE TO PREVIOUS FORECAST TRACK OR REASONING. THE NHC MODEL
GUIDANCE CONTINUES TO BE IN EXCELLENT AGREEMENT ON DORIAN MOVING IN
A GENERAL WEST-NORTHWESTWARD DIRECTION THROUGHOUT THE FORECAST
PERIOD. THE MAIN DIFFERENCE BETWEEN THE MODELS CONTINUES TO BE THE
FORWARD SPEED OF DORIAN...WITH THE ECMWF AND HWRF BEING THE FASTEST
MODELS WITH A WEAKER CYCLONE...WHILE THE GFS AND GFS-ENSEMBLE MEAN
MODELS ARE THE SLOWEST DUE TO THEIR FORECASTING A STRONGER VORTEX.
BASED ON THE BETTER PERFORMANCE OF THE GFS MODEL INTENSITY
FORECASTS OVER THE PAST FEW DAYS...THE OFFICIAL FORECAST LEANS
TOWARD THE LATTER SOLUTION AND SHOWS A GRADUAL DECREASE IN FORWARD
SPEED TO BEGIN BY 48-72 HOURS AS DORIAN APPROACHES A WEAKNESS IN
THE SUBTROPICAL RIDGE. THE NEW TRACK FORECAST IS JUST AN EXTENSION
OF THE PREVIOUS ADVISORY TRACK...AND IS VERY CLOSE TO BUT SLOWER
THAN THE CONSENSUS MODEL TVCN.

DORIAN APPEARS TO HAVE SURVIVED PASSAGE OVER THE REGION OF COOLEST
SSTS OVERNIGHT AND IS NOW MOVING OVER AND TOWARD WARMER WATERS.
ALTHOUGH THE AFOREMENTIONED EQUATORIAL INFLOW OF WARM UNSTABLE AIR
LIKELY HELPED OFFSET THE COOLING BENEATH DORIAN...THAT LIFELINE IS
FORECAST BY ALL OF THE MODELS TO BE CUT OFF DURING THE NEXT 24
HOURS...WHICH WILL RESULT IN THE COMPACT CYCLONE MOVING THROUGH A
REGION OF DECREASING MID-LEVEL MOISTURE AND MORE STABLE AIR...
PRODUCING SOME SLIGHT WEAKENING FOR THE NEXT 24 HOURS OR SO. AFTER
THAT...THE VERTICAL SHEAR IS EXPECTED TO REMAIN AT OR BELOW 10-15
KT...WHICH WOULD FAVOR AT LEAST SOME GRADUAL INTENSIFICATION IF THE
INNER CORE CONVECTION CAN REMAIN INTACT. THE OFFICIAL INTENSITY
FORECAST LIES BETWEEN THE SHIPS AND LGEM SOLUTIONS...AND ASSUMES
DORIAN WILL SURVIVE ITS TREK THROUGH UNFAVORABLE THERMODYNAMIC
CONDITIONS DURING THE NEXT 2 DAYS.

FORECAST POSITIONS AND MAX WINDS

INIT 25/1500Z 16.0N 35.9W 50 KT 60 MPH
12H 26/0000Z 16.6N 38.5W 45 KT 50 MPH
24H 26/1200Z 17.4N 42.3W 45 KT 50 MPH
36H 27/0000Z 18.0N 46.2W 50 KT 60 MPH
48H 27/1200Z 18.7N 49.9W 50 KT 60 MPH
72H 28/1200Z 19.8N 57.0W 55 KT 65 MPH
96H 29/1200Z 20.7N 63.0W 60 KT 70 MPH
120H 30/1200Z 21.5N 67.5W 60 KT 70 MPH

$$
FORECASTER STEWART

[Senobia]

06Z NAVGEM pulling an IKE like track....diving big time SW.....then ends up heading to the keys.....might be GOM bound if it went out further...big change from the 0Z


https://www.fnmoc.navy.mil/wxmap_cgi/cg ... t=Tropical


full alert now!

Stop being scary!

Are you taking this track seriously or are you making fun of it? Honest question because it's hard to tell when people get into these model wars.

[jaguarjace]

Hey all, can someone please upload an RGB floater animation from This link to ImageShacks just before sunset and post the URL here in the forums. Since I'm from Australia I won't have access to the evening loops because I'll still be sleeping. Much is appreciated.

[Senobia]

IKE comes to mind. It did not follow climo at all. Yes it formed further west than our current system but look how it entered the Cuban coast after reaching 23N 60W and then the Gulf. That was an unusual track and it went from 35W to 95W. I am not saying that will happen now just pointing it out.

Not diggin' this scenario at all, but have heard it mentioned a few times. Anyone else have thoughts on this, how likely you think Dorian is to follow Ike's path?

[Bocadude85]

IKE comes to mind. It did not follow climo at all. Yes it formed further west than our current system but look how it entered the Cuban coast after reaching 23N 60W and then the Gulf. That was an unusual track and it went from 35W to 95W. I am not saying that will happen now just pointing it out.

Not diggin' this scenario at all, but have heard it mentioned a few times. Anyone else have thoughts on this, how likely you think Dorian is to follow Ike's path?

I would say the chance is probably less then 1%. None of the current models are showing this scenario. The closest model run to Ikes path that I can see is the 6z NAVGEM and that model is not very reliable in my opinion.

[Alyono]

Not sure cool waters is the issue at the present time.

There looks to be some shear. Visible imagery seems to indicate that the center is west of the convection

[TheStormExpert]

IKE comes to mind. It did not follow climo at all. Yes it formed further west than our current system but look how it entered the Cuban coast after reaching 23N 60W and then the Gulf. That was an unusual track and it went from 35W to 95W. I am not saying that will happen now just pointing it out.

http://weather.unisys.com/hurricane/atl ... /track.gif

Not diggin' this scenario at all, but have heard it mentioned a few times. Anyone else have thoughts on this, how likely you think Dorian is to follow Ike's path?

I'd say the odds of this type of track are very slim. In my opinion!

[Stormlover2012]

1 percent hitting texas or 1 percent of taking that same exact path?

[RL3AO]

12z GFS is running. Looks like WCOSS is the operational computer from here out.

[RL3AO]

Might be pulling in some dryer air from the SW. Probably won't be too big of a deal though.

[ROCK]

06Z NAVGEM pulling an IKE like track....diving big time SW.....then ends up heading to the keys.....might be GOM bound if it went out further...big change from the 0Z


https://www.fnmoc.navy.mil/wxmap_cgi/cg ... t=Tropical


full alert now!

Stop being scary!

Are you taking this track seriously or are you making fun of it? Honest question because it's hard to tell when people get into these model wars.

Its the NAVGEM...aka NOGAPS...which besides the NAVY and Dr Masters many do not take it seriously...including me. I just like to show everyone the different model runs besides the GFS. I did put a LOL at the end there....

[cycloneye]

It appears the MLC and LLC are not joint now as the LLC is moving westward with little convection and almost exposed.With that decouple I would say the LLC is moving closer to 20 mph to the west now. That is also going to result in a model shift within the next two runs due to the return to westward motion from WNW.

[WeatherEmperor]

06Z NAVGEM pulling an IKE like track....diving big time SW.....then ends up heading to the keys.....might be GOM bound if it went out further...big change from the 0Z


https://www.fnmoc.navy.mil/wxmap_cgi/cg ... t=Tropical


full alert now!

Stop being scary!

Are you taking this track seriously or are you making fun of it? Honest question because it's hard to tell when people get into these model wars.

Its the NAVGEM...aka NOGAPS...which besides the NAVY and Dr Masters many do not take it seriously...including me. I just like to show everyone the different model runs besides the GFS. I did put a LOL at the end there....

Careful Rock. The Euro might get upset if you look at the Navgem too much.

Sent from my HTC EVO 4G LTE

[ROCK]

agree Luis....dived SW also after some shear unstacked him....

[blp]

06Z NAVGEM pulling an IKE like track....diving big time SW.....then ends up heading to the keys.....might be GOM bound if it went out further...big change from the 0Z


https://www.fnmoc.navy.mil/wxmap_cgi/cg ... t=Tropical


full alert now!

No Kidding.... on a side note are you now a NAVGEM hugger? I remember you were a Euro hugger in years past

[ROCK]

06Z NAVGEM pulling an IKE like track....diving big time SW.....then ends up heading to the keys.....might be GOM bound if it went out further...big change from the 0Z


https://www.fnmoc.navy.mil/wxmap_cgi/cg ... t=Tropical


full alert now!

No Kidding.... on a side note are you now a NAVGEM hugger? I remember you were a Euro hugger in years past

nah, its just the NAVGEM updates 4 times a day....EURO only 2...plus the EURO has been all over the place lately. However, given current presentation of Dorian maybe the EURO is not all that whacked out. We will see....

[SFLcane]

Yeah, the cloud structure has been deteriorating.

[wxman57]

* ATLANTIC SHIPS INTENSITY FORECAST *
* GOES AVAILABLE, OHC AVAILABLE *
* DORIAN AL042013 07/25/13 12 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
SHEAR (KT) 5 0 5 8 11 9 9 9 12 15 16 23 25

12z shear down from 33kt's at 120 hours...

Yeah, those SHIPS forecasts are not exactly reliable at the best of times that far out!

There is a trend for a region of higher shear to be present by 120hrs, but we'll see!

One thing to note about the SHIPS shear values is that it computes shear over a very large latitude range, extending WAY north of Dorian. That shear is not calculated for the area directly in Dorian's path. Dorian, being a small storm may not be impacted by shear that's more than 100 miles to its north.