ATL: DORIAN - Post-Tropical - Discussion

[SouthDadeFish]

The lower-tropospheric circulation is barely closed. Looking at the G-IV drops, it seems like there is a bit of mid-level shear out of the north that may be advecting dry air into the core of the TC. Dorian is not a healthy tropical cyclone right now, which is good news. It remains to be seen if the tiny storm can survive another couple of days of unfavorable environmental conditions.

[tropicsPR]

Grantley Adams International Airport, Barbados
NE 38 G 55

https://w1.weather.gov/data/obhistory/TBPB.html

[gatorcane]

Interesting setup ahead for Dorian. Really depends on not only what land interaction and the very dry air currently over the Eastern Caribbean and Puerto Rico does to him. The good news is that the OP GFS and ECMWF - the best two models in the world - keep him small and not too significant into Florida at least for now. The inferior models such as the NOGAPS and ICON show something much more significant. The NOGAPS has been calling for Florida for the past day two days, I can’t remember the last time the NOGAPS nailed a 7+ day TC forecast beating out the GFS and Euro. That said, the time of year and where Dorian is headed is always cause for alarm. But until you get those big models on board, there is at least some hope Dorian won’t become anything very significant. Watching closely here in SE Florida but cautiously optimistic this ends up not amounting to much.

[Highteeld]

I see what you are saying.
But which flight were these from? Confused here...

I just posted about the NOAA one too which is the one you are now talking about. It has had some higher SFMR values, though at the time the flight level winds were not as high at the time. The flight level winds were a little higher in the previous set though and they were all in the NE quadrant.

The four values I was talking about that were likely not correct were from the Air Force mission because they were all very near, to perhaps over, Barbados. Coordinates may not reflect quite the exact path of the plane because they happen every 30 seconds and they are rounded slightly in the HDOB message. SFMR estimated surface winds are 10 second estimates taken from the highest 10 second estimated surface winds estimated during the 30 second period between those HDOBs. Even if a coordinate icon isn't exactly over the coast, it might include part of the time over land. Being the coordinate isn't right over land, maybe that was why some don't get flagged. But they were very close to land, so I assume shallow water where SFMR doesn't work well. How shallow it has to be before it doesn't work as well I don't know.

Yeah, it's a good question regarding where the line is drawn on SFMR -- how deep does the water have to be for it to be considered reliable. On a tangent, a major point of contention last year was Hurricane Michael's 138-139 knot SFMR before landfall in Mexico Beach. Initially it was not used, but then it was used for the reanalysis, but with some degree of uncertainty from the NHC.

[Dylan]

 https://twitter.com/dylanfedericowx/status/1166158347936174080

[Chris_in_Tampa]

Grantley Adams International Airport, Barbados
NE 38 G 55

https://w1.weather.gov/data/obhistory/TBPB.html

It has not updated for me on that page yet, but the ob is updated on this version of the page:
https://forecast.weather.gov/data/obhistory/TBPB.html

[psyclone]

Dorian looks to be a very unhealthy storm in a hostile environment with potential big land hazards. If it can make it north of the greater Antilles it might find itself in a more hospitable situation but at this point it seems dissipation is very much on the table. I'm hoping our weekend in florida isn't disrupted

[Chris_in_Tampa]

Yeah, it's a good question regarding where the line is drawn on SFMR -- how deep does the water have to be for it to be considered reliable. On a tangent, a major point of contention last year was Hurricane Michael's 138-139 knot SFMR before landfall in Mexico Beach. Initially it was not used, but then it was used for the reanalysis, but with some degree of uncertainty from the NHC.

I can't recall all the reasons they upgraded, but they had multiple, not just recon as the basis for upgrading later.

Here is a closer example of three of the obs in that one message that were likely not correct for the SFMR. Top left value was suspect, but the next two along the flight path, down to the bottom right, were not. But you can see that even if the coordinates were precise, it likely traveled over land between two points and the last one was over very shallow water. (based on being able to see the ocean floor through the water and what are either sandbars or breaking waves over possible sandbars or very shallow water)

[artist]

013330 1323N 05909W 8430 01574 0127 +137 +098 113046 047 044 043 00
013400 1321N 05911W 8420 01583 0124 +144 +103 120042 048 048 031 03
013430 1320N 05912W 8438 01567 0116 +159 +104 123036 038 040 010 00

[abajan]

little barbados is causing all sorts of distortion lol.

...

Yes. We're small but wield lots of influence. Rihanna's from here!

[Weatherboy1]

Wasn’t there just a vortex data message showing central pressure down another 2 MBs to 1003 (from recon thread)?

[artist]

Wasn’t there just a vortex data message showing central pressure down another 2 MBs to 1003 (from recon thread)?

Yes

[1900hurricane]

Wasn’t there just a vortex data message showing central pressure down another 2 MBs to 1003 (from recon thread)?

It's extrapolated, but I ran KZC on it anyway. I get 44-45 kt, again very much in line with the SFMR data.

[msbee]

Light rain and fairly frequent thunder at the moment. Absolutely spectacular sunset earlier.

Be careful down there!

[Frank2]

The lower-tropospheric circulation is barely closed. Looking at the G-IV drops, it seems like there is a bit of mid-level shear out of the north that may be advecting dry air into the core of the TC. Dorian is not a healthy tropical cyclone right now, which is good news. It remains to be seen if the tiny storm can survive another couple of days of unfavorable environmental conditions.

Good to get a Meteorologist's opinion - just my own guess, but I think everyone abandoned yesterday's opinion too quickly that said shear and dry air in the Eastern Caribbean would weaken or dissipate the system.

Just ahead of Dorian is a large egg-shaped area of up to 35Kts of shear and unusually dry air (4% RH at this afternoon's balloon sounding from Guadeloupe).

P.S. And I'm having dental issues and the last thing I need is to drive 12 hours to a hotel : (

Frank

[Nancy Smar]

AL, 05, 2019082700, 03, OFCL, 0, 130N, 592W, 45, 0, TS, 34, NEQ, 40, 30, 0, 40, 0, 0, 0, 55, 0, , 0, , 0, 0, , , 12, NEQ, 60, 40, 30, 60,
AL, 05, 2019082700, 03, OFCL, 12, 140N, 613W, 50, 0, TS, 34, NEQ, 40, 30, 20, 40, 0, 0, 0, 60, 0,
AL, 05, 2019082700, 03, OFCL, 12, 140N, 613W, 50, 0, TS, 50, NEQ, 20, 20, 0, 20, 0, 0, 0, 60, 0,
AL, 05, 2019082700, 03, OFCL, 24, 152N, 635W, 55, 0, TS, 34, NEQ, 50, 40, 30, 50, 0, 0, 0, 65, 0,
AL, 05, 2019082700, 03, OFCL, 24, 152N, 635W, 55, 0, TS, 50, NEQ, 20, 20, 10, 20, 0, 0, 0, 65, 0,
AL, 05, 2019082700, 03, OFCL, 36, 165N, 655W, 60, 0, TS, 34, NEQ, 50, 40, 30, 50, 0, 0, 0, 75, 0,
AL, 05, 2019082700, 03, OFCL, 36, 165N, 655W, 60, 0, TS, 50, NEQ, 20, 20, 10, 20, 0, 0, 0, 75, 0,
AL, 05, 2019082700, 03, OFCL, 48, 179N, 676W, 65, 0, HU, 34, NEQ, 60, 50, 40, 60, 0, 0, 0, 80, 0,
AL, 05, 2019082700, 03, OFCL, 48, 179N, 676W, 65, 0, HU, 50, NEQ, 30, 30, 20, 30, 0, 0, 0, 80, 0,
AL, 05, 2019082700, 03, OFCL, 48, 179N, 676W, 65, 0, HU, 64, NEQ, 15, 10, 0, 15, 0, 0, 0, 80, 0,
AL, 05, 2019082700, 03, OFCL, 72, 210N, 710W, 50, 0, TS, 34, NEQ, 60, 50, 30, 60, 0, 0, 0, 60, 0,
AL, 05, 2019082700, 03, OFCL, 72, 210N, 710W, 50, 0, TS, 50, NEQ, 30, 20, 0, 30, 0, 0, 0, 60, 0,
AL, 05, 2019082700, 03, OFCL, 96, 240N, 748W, 55, 0, TS, 34, NEQ, 0, 0, 0, 0, 0, 0, 0, 65, 0,
AL, 05, 2019082700, 03, OFCL, 120, 265N, 790W, 60, 0, TS, 34, NEQ, 0, 0, 0, 0, 0, 0, 0, 75, 0,

[Hypercane_Kyle]

AL, 05, 2019082700, 03, OFC

NHC sticking to their guns as far as the official forecast goes: Hurricane by the time it threads the gap between Hispaniola/PR, approaching hurricane status now before reaching Florida.

[AtlanticWind]

Satellite Presentation not as impressive tonight.

[HDGator]

AL, 05, 2019082700, 03, OFC

NHC sticking to their guns as far as the official forecast goes: Hurricane by the time it threads the gap between Hispaniola/PR, approaching hurricane status now before reaching Florida.

Yeah, and in keeping with NHC history they keep the uncertain 5-day forecast offcoast. That cone will still cover most of SE Florida and will be on the front page tomorrow morning.

[ObsessedMiami]

I went out and got my generator gas and the last batteries I need. So come what may I am not going to have to stand in those obscene lines for gas like Irma. I hope he fizzles and doesn’t do anyone damage but I am ready either way. It was a good feeling to have it all taken care of this early. Hopefully for nothing.
Peace to Barbados and neighbors tonight