ATL: DORIAN - Post-Tropical - Discussion

[RL3AO]

The link for the NCEP site won't update as its connected to the old CCS computer. I can't find the link to the new WCOSS version on the NCEP site, but I know its around here somewhere.

[chaser1]

Just read you guys' prior posts regarding the upgrade/update GPS system, and will check out link as posted

[otowntiger]

A little climo from the Coastal Services Center website. Question - how many storms of the past which passed within 65NM of Dorian's current position reached the Caribbean or the Gulf? Answer - zero. A recurve near the Bahamas looks most likely, but I'd pay close attention in Florida. My money currently is on the Carolinas.

I agree with this generally except I think it may even miss the Bahamas, but I'm no professional - just looking at your climo summary based on its high latitude and what storms usually do.

BTW, somewhat off topic, why do we call it "re-curve"? Why not just 'curve'? To me 're-curve' would imply that it will curve again. I know what is meant by the term just don't know why that term is used to describe a storm that will turn out to sea before threatening land.

I said it would likely recurve near the Bahams, not necessarily in the Bahamas. The word "recurve" means to bend back/backwards, implying that not only will Dorian curve northward but will curve so much that it goes backwards in longitude.

Thanks for the reply and clarification. I didn't mean to say you thought it would hit the Bahamas either. Its just hard to get too worked up over this storm being a huge threat at this point in time especially give the climo regarding path and the unknowns about its ultimate intensity. Thanks again for your professional and rational input on this board.

[chaser1]

hmmm, maybe the EURO was not all that jacked up after all...should be coming out in a few hours....

Yeah, am starting to think that the Euro was not that off, at least with regards to system strength. Though (and I could well be wrong here), didn't the Euro have Dorian significantly re-curving north as well?

Either way though, unless we see a decent resurgence of convection during the day, Dorian may start having some "gastric" issues due to the dryer air it may be ingesting.

[MiamiensisWx]

To be fair, Dorian is weakening on the 12z GFS before it even reaches Hispaniola, it has a sheared look to it (IE convection is displaced east of the low pressure)

There is much more interaction with the upper low prior to landfall in Hispaniola, so you are correct re: shear.

[Weatherboy1]

Waaayyyyy early to say whether Dorian will impact the U.S. anywhere, much less here in South FL. But it's worth noting that the NWS Miami discussion notes how the current "trough just to our north" pattern that has been in place for a while looks to be changing, and the winds shifting from SW to S to E over the next few days. That would imply that ridging in the Western Atlantic may be rebuilding early next week -- a possible factor that might steer Dorian closer to FL. Snippet below:

"LONG TERM...
HIGH PRESSURE OVER THE FLORIDA KEYS WILL SHIFT NORTHWARD INTO
SOUTH FLORIDA THIS WEEKEND BEFORE CONTINUING TO MOVE NORTH INTO
CENTRAL FLORIDA BY EARLY NEXT WEEK. THIS WILL ALLOW FOR THE
STEERING FLOW TO SHIFT TO A SOUTHERLY DIRECTION THIS
WEEKEND...BEFORE SWINGING BACK TO A EASTERLY DIRECTION EARLY NEXT
WEEK. SO POPS THIS WEEKEND INTO EARLY NEXT WEEK WILL BE IN A
SCATTERED RANGE WITH THE BEST COVERAGE OVER THE INTERIOR AND WEST
COAST METRO AREAS.

FOR MIDDLE TO END OF NEXT WEEK...ALL EYES WILL BE ON THE STRENGTH
AND POSITION OF TROPICAL STORM DORIAN. SO THIS IS A GOOD TIME TO
REVIEW YOUR SUPPLIES FOR A TROPICAL SYSTEM."

[gatorcane]

hmmm, maybe the EURO was not all that jacked up after all...should be coming out in a few hours....

Yeah, am starting to think that the Euro was not that off, at least with regards to system strength. Though (and I could well be wrong here), didn't the Euro have Dorian significantly re-curving north as well?

Either way though, unless we see a decent resurgence of convection during the day, Dorian may start having some "gastric" issues due to the dryer air it may be ingesting.

Yes the Euro has been way off with this system for many days now.

But maybe it gets a better handle on the system as it gets further west.

[tolakram]

Some saved images from the 12Z GFS. Dissipates on Hispaniola, looks like remains track into the gulf with no further development.

[chaser1]

Based upon the current satellite appearance, Dorian is being undermined by the strong easterly trade winds in which it is currently embedded. This is allowing the LLC to outrun the MLC on the most recent satellite images. Thus, due to easterly shear, the center is outrunning the +PVA (convection); and because Dorian is such a small system, the impact on the strength would be strongly negative within the next 36-48 hours. Because Dorian is already so far N and E, climatology for similar systems in July usually indicates that systems in Dorian's location do not survive long due to cooler waters and higher stability N of 15°N and E of 55°W. I would not be surprised if Dorian deteriorates into a mostly-naked swirl in 24 hours, meaning a much faster movement through the next three days. That would place the system over the Leeward Islands in about three days; and if Dorian has lost much of its organization by then, it will struggle to avoid getting entangled in Hispaniola before it has a chance to regenerate. That could mean heavy rainfall or flash flooding for the islands and is in line with the ECMWF and GEM solutions, which at 72 hours are farther south than the model consensus.

Yeah, I think you're "dead on", plus (appologize for the duplicate partial post from Models thread) I get the impression that Dorian is about to hit the 500 pound (well really 500mb) wall. Looking at satellite just now, I am not sure if I am looking at a significant ribbon of Alto-Cumulus that looks to be fast approaching from the North and East. This would appear to be the present 594 ridge perhaps starting to press a bit further west and south as forecasted perhaps?? If this is so than I can see how Dorian in the near term, may be impacted and be forced on a more westerly course. The other potential result might in fact be a faster motion in the near term as well. Finally, if this were to come to fruition, than based on the more stable air it is ingesting for the next day or two, a more rapid forward motion would likely contribute to it having a harder time maintaining what little convection it has now and impact its vertical structure at least somewhat.

[ConvergenceZone]

even though it's not looking good at the moment, I still think it will survive....

[tolakram]

16:15Z

[chaser1]

Waaayyyyy early to say whether Dorian will impact the U.S. anywhere, much less here in South FL. But it's worth noting that the NWS Miami discussion notes how the current "trough just to our north" pattern that has been in place for a while looks to be changing, and the winds shifting from SW to S to E over the next few days. That would imply that ridging in the Western Atlantic may be rebuilding early next week -- a possible factor that might steer Dorian closer to FL. Snippet below:

"LONG TERM......THIS WILL ALLOW FOR THE
STEERING FLOW TO SHIFT TO A SOUTHERLY DIRECTION THIS
WEEKEND...BEFORE SWINGING BACK TO A EASTERLY DIRECTION EARLY NEXT
WEEK.

Yeah, I'd agree that Dorian may likely have other problems to deal with well before making itself this far west, but of greater significance is the interesting "ebb & flow" of present and future steering conditions. Might well be a mute point with regards to Dorian, but i'm actually much more interested in where the "big boys" are gonna go come mid August

[Alyono]

SAL SURGE SAL SURGE

The decoupling is a tell tale sign of a low level easterly wind surge associated with the SAL

[Aric Dunn]

yeah clearly dry air/ sal has found its way in. can it work it out is the question.

[Alyono]

SAL caught up from the EAST, not the west

This just goes to show, do not pay much attention to the dry air AHEAD of a trop Atl system... its the air behind that is the key

The shear is entirely due to the SAL this morning

[tailgater]

yeah clearly dry air/ sal has found its way in. can it work it out is the question.

Note the difference in 2 1/2 days
http://tropic.ssec.wisc.edu/real-time/s ... litE5.html

[cycloneye]

Joe Bastardi ‏@BigJoeBastardi 26m

Well I hear we have a new super computer running the GFS. Response: Take Dorian into Caribbean islands and kill it. I doubt that

[tolakram]

16:45Z

[cycloneye]

The squadron will have the first mission tentative for next Sunday morning.

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT THU 25 JULY 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 26/1100Z TO 27/1100Z JULY 2013
TCPOD NUMBER.....12-055

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. ADDITIONAL DAY OUTLOOK: BEGIN 6-HRLY FIXES FOR TROPICAL
STORM DORIAN AT 28/1200Z NEAR 19.8N 57.0W.

[jlauderdal]

The squadron will have the first mission tentative for next Sunday morning.

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1030 AM EDT THU 25 JULY 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 26/1100Z TO 27/1100Z JULY 2013
TCPOD NUMBER.....12-055

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. ADDITIONAL DAY OUTLOOK: BEGIN 6-HRLY FIXES FOR TROPICAL
STORM DORIAN AT 28/1200Z NEAR 19.8N 57.0W.

that might be the longest lead time i have ever seen for the squadron