ATL: DORIAN - Post-Tropical - Discussion

[Gustywind]

Dorian's recap of the day given SSD numbers.


DATE/TIME LAT LON CLASSIFICATION STORM
25/2345 UTC 16.9N 38.0W T2.0/3.0 DORIAN
25/1745 UTC 16.4N 37.1W T2.0/3.0 DORIAN
25/1145 UTC 15.9N 34.9W T3.0/3.5 DORIAN

[gatorcane]

If the blue circle is a ridge, wouldn't that cause Dorian to go SW instead of a recurve? Please don't beat me up to bad, I truly am a novice!!

Yes more like WSW but if you look at the latest model guidance a few models start bending Dorian more WSW starting around 120 hours from now, over Cuba.

Of course keep in mind just 24 hours ago many models showed a recurve east of the Bahamas, so these models are not set in stone by any means since it's still the medium to long-range.

If you go to the models thread, you can see the latest models.

[boca]

Dorian might end up getting pushed SW into the Eastern end of Cuba due to that ridge orientating itself over Florida NE to SW

[gatorcane]

Starting to see some models bend to the WSW now just after day 5. What a difference to what these models were showing just 24 hours ago.

[Nikki]

If the blue circle is a ridge, wouldn't that cause Dorian to go SW instead of a recurve? Please don't beat me up to bad, I truly am a novice!!

Yes more like WSW but if you look at the latest model guidance a few models start bending Dorian more WSW starting around 120 hours from now, over Cuba.

Of course keep in mind just 24 hours ago many models showed a recurve east of the Bahamas, so these models are not set in stone by any means since it's still the medium to long-range.

If you go to the models thread, you can see the latest models.

Thank you so much! I usually just sit back and watch and read, but I just had to ask! I am trying to learn!

[Nederlander]

I have a question about the BAM suite. I have noticed this before, but never really questioned it. I noticed on the 0z run, the shallow layer BAM is significantly farther out (close to Belize) while the mid and deep layers are hanging around the Bahamas and Puerto Rico, respectively within the same time frame. Does the shallow layer BAM typically show a faster moving system? This seems like a huge difference in expected forward speeds...

[ROCK]

I have a question about the BAM suite. I have noticed this before, but never really questioned it. I noticed on the 0z run, the shallow layer BAM is significantly farther out (close to Belize) while the mid and deep layers are hanging around the Bahamas and Puerto Rico, respectively within the same time frame. Does the shallow layer BAM typically show a faster moving system? This seems like a huge difference in expected forward speeds...

shallow and caught up more in the fast easterlies sort of like it is now.....


the NAVGEM and GFS have been considering a SW dip ala IKE last runs.....Where is WXMN57 and his CLIMO? he might have went into hiding with FCI....

that 2% gets you every time...

[cycloneye]

Closer to San Juan PR at 11 PM EDT.

Results for San Juan, Puerto Rico (18.45N, 66W):
The approximate Closest Point of Approach (CPA) is located near 20.4N, 65.8W or about 131.9 miles (212.3 km) from your location. The estimated time of when the center of the storm will be at that location is in about 3 days, 17 hours and 3 minutes from now (Monday, July 29 at 4:18PM AST).


http://stormcarib.com/closest.cgi

[northjaxpro]

Still lots of time for things to evolve folks. I am certain more fluctuations and windshield-wipering from the models are still to come.

However, I will say that if Dorian can somehow hold together and survive over these next several days, the curving poleward scenario looks to be decreasing as time progresses. Should the strength of that ridge verify, I don't foresee any curve northward down the road.

[boca]

Dorian might be a Caribbean cruiser after all.That was the outlier wild card last night about this time.

[Gustywind]

SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.6N 39.6W
ABOUT 1550 MI...2500 KM E OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 20 MPH...32 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


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

INTERESTS IN THE NORTHERN LEEWARD ISLANDS SHOULD MONITOR THE
PROGRESS OF DORIAN.

Is that a slight west turn attempt trying to begin a bit early than predicted in the previous 5PM discussion? In that case the Leewards islands and PR should be on their guard for sure. Let's follow closely the situation.
From 11 PM discussion: DORIAN IS MOVING TOWARD THE WEST-NORTHWEST NEAR 20 MPH...32 KM/H. A TURN TOWARD THE WEST WITH AN INCREASE IN FORWARD SPEED IS FORECAST ON FRIDAY.

[chaser1]

If the blue circle is a ridge, wouldn't that cause Dorian to go SW instead of a recurve? Please don't beat me up to bad, I truly am a novice!!

Thank you so much! I usually just sit back and watch and read, but I just had to ask! I am trying to learn!

That's what this is all about Teach others, learn from others

[gatorcane]

The NHC mentioned they leaned more on the ECMWF track for the 11 PM EST discussion:

THE NHC TRACK FORECAST HAS BEEN NUDGED A BIT SOUTH OF THE PREVIOUS
FORECAST TO FOLLOW THE OVERALL TREND IN THE GUIDANCE...BUT IT ENDS
UP CLOSE TO THE ECMWF TRACK ON THE NORTHERN SIDE OF THE ENVELOPE

http://www.nhc.noaa.gov/text/refresh/MI ... 0241.shtml

Well here is the 12Z ECMWF 120 hour position for Dorian. Pretty good low-level ridge to the north and since Dorian stays weak it keeps moving west eventually through the FL straits on this run:

[SFLcane]

[boca]

Is that map from this afternoon or the latest info?

[chaser1]

To throw in my two cents, if it is detaching from the ITCZ, I assume this could potentially cause a temporary reduction in convective intensity as its shedding a source of energy, similar to how many convection-heavy subtropical cyclones seem to flare down in convection as they separate from the frontal system before strengthening.

Interestingly enough, as I'm looking at the departing ITCZ "southern wave access" move out and ahead to the west, I can almost make out some slight amount of mid level turning around 9N & 43W. Other than the less than ideal conditions and quick forward motion, it wouldn't be the first time we've seen the lower section of a forward tilted wave axis begin to congeal and slowly develop. Other difference here, is most times in the past, it seems that this occurs when the parent low or depression is off to the Atlantic graveyard (and not moving westward as well)

[chaser1]

Still lots of time for things to evolve folks. I am certain more fluctuations and windshield-wipering from the models are still to come.

However, I will say that if Dorian can somehow hold together and survive over these next several days, the curving poleward scenario looks to be decreasing as time progresses. Should the strength of that ridge verify, I don't foresee any curve northward down the road.

Do you hear that "Houston" I thought I heard that lightning can strike twice!

[JonathanBelles]

New Blog Post: viewtopic.php?p=2323547#p2323547

[TheStormExpert]

From Tropical Tidbits (Levi Cowan) Facebook Page:

[cycloneye]

Here is what the San Juan NWS says about Dorian and possible effects in Puerto Rico.

THE GFS IS TAKING DORIAN ALONG THE NORTH COAST
OF PUERTO RICO ON MONDAY NIGHT. ALTHOUGH THIS IS A POSSIBILITY...
IT IS NOT THE OFFICIAL NATIONAL HURRICANE CENTER TRACK...NOR ONE
WE WOULD CONSIDER TO BE THE HIGHEST PROBABILITY AT THIS
TIME...THEREFORE THE OUTPUT FROM THE GFS FOR WINDS AND PRECIP
QUANTITIES AND PROBABILITIES CANNOT BE USED TO POPULATE THE GRIDS
FROM ABOUT SUNDAY THROUGH WEDNESDAY. PRESENTLY IT LOOKS LIKE
TYPICAL PRECIPITATION PATTERNS FOR EASTERLY OR SLIGHTLY
NORTHEASTERLY WINDS WILL APPLY AND HAVE ADDED SOME POP FOR WESTERN
PUERTO RICO ON SUNDAY. OTHERWISE NO OTHER CHANGES WERE MADE.
DORIAN SHOULD BEGIN TO AFFECT THE WEATHER IN THE U.S. VIRGIN
ISLANDS AND PUERTO RICO SUNDAY/SUNDAY NIGHT...WITH EFFECTS INCREASING
MONDAY AHEAD OF A MONDAY AFTERNOON/EVENING PASSAGE TO THE NORTH.
THE BIG UNCERTAINTY IS HOW FAR TO THE NORTH IT WILL PASS. THIS
QUESTION SHOULD BE ANSWERABLE BY SATURDAY OR SUNDAY.