ATL: TROPICAL DEPRESSION TWO - DISCUSSION

[KWT]

41kts at Flight level found by rexon, probably very close to being enough to upgrade to Bonnie, only question is whether there actually still a closed low level circulation...

[jasons2k]

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[djones65]

Recon is located at 26.2N and 95.5W reporting SE winds 41 knots at 975 mb and SFMR is measuring 34 knots. Plane heading southwestward at the moment. Interestingly, aircraft recently ascended from 975 mb up to 921 mb... during the same time extrapolated pressure increased from 1007 to 1009 mb (I personally believe the surface pressure extrapolation may have been error due to the aircraft altitude increase during the same time as it is obviously still heading towards the center. Winds have veered from 125 degrees to 147 degrees so maybe the center is farther west? If SFMR is accurate i would not be surprised to see them continue to find tropical storm force surface winds, but will they upgrade if satellite presentation doesn't improve?

[x-y-no]

Recon is located at 26.2N and 95.5W reporting SE winds 41 knots at 975 mb and SFMR is measuring 34 knots. Plane heading southwestward at the moment. Interestingly, aircraft recently ascended from 975 mb up to 921 mb... during the same time extrapolated pressure increased from 1007 to 1009 mb (I personally believe the surface pressure extrapolation may have been error due to the aircraft altitude increase during the same time as it is obviously still heading towards the center. Winds have veered from 125 degrees to 147 degrees so maybe the center is farther west? If SFMR is accurate i would not be surprised to see them continue to find tropical storm force surface winds, but will they upgrade if satellite presentation doesn't improve?

I suppose they may have intended to fly at 975, but found stronger winds than they expected so ascended a bit.

Funny, it almost looked to me like they overshot their descent since they were only at 975 for less than half a set, but that would be pretty extraordinary.

[djones65]

Last set of high density observations showed SFMR winds of 34 to 36 knots over large area. Highest flight level which is now at 925 mb was 42 knots. It's right on the cusp, but I don't think one can argue if they upgrade to Bonnie based on the SFMR and flight level wind measurements... At least that is my opinion...

[cycloneye]

The headline of the 7 AM CDT advisory is:

BULLETIN
TROPICAL DEPRESSION TWO INTERMEDIATE ADVISORY NUMBER 2A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022010
700 AM CDT THU JUL 08 2010

...POORLY-ORGANIZED TROPICAL DEPRESSION EXPECTED TO BRING RAINS TO
SOUTHERN TEXAS AND NORTHEASTERN MEXICO....

[Thunder44]

There is closed surface circulation somewhere. Matamoros,MX is reported a NNW at 7 mph

http://weather.noaa.gov/weather/current/MMTM.html

And Tampico,MX is reporting WSW at 12mph

http://weather.noaa.gov/weather/current/MMTM.html

[clfenwi]

In place observations will trump satellite appearance every time. The sword cuts both ways; in this case it is in the storm's favor to have the plane around.

It does seem like they intended to fly this like mission like the depression was an unclassified system, at 1000 ft, before thinking better of it. Like x-y-no said, they were only down there for about half an ob set, but that's still five minutes; an eternity for flying at the "wrong altitude" if it were an accidental overshoot.

[KWT]

Well recon does suggest something close to 35kts than 30kts so it just depends on whether the NHC wants to upgrade it or not. As has been aid the presentation still isn't great, even if it has gained some convection in the last 4hrs or so.

Chances of upgrade has increased though with the winds being suggestive of something close to 35kts.

[djones65]

Aircraft is finding tropical storm force winds... SFMR reported 40 knots within the past 10 minutes... HOWEVER, they cannot close off a circulation... The winds went from SE to E to ENE to E and ESE as they crossed from NE to SW through the depression... Current position is 25.2N and 96.8W only about 35 miles from the Mexican coast or a little less... Hmmm.. May not have a well defined center, but like what Thunder44 reported there is obviously a low pressure area based on surrounding obs... The pressure is a little higher also so that the surface circulation may be dissipating? This is not official information whatsoever and only my opinion based on recon observations.

[Frank2]

Yes, it's about the poorest excuse for a TD, though in all fairness when it was upgraded it looked much more impressive...

Persistence is the key, and the flare-up last night only lasted a few hours, but even with a lack of persistence it apparently was enough to cause the system to be upgraded...

As you said some winds are near or at TS speeds, and that was probably the main reason for the upgrade to TD status, since to not upgrade it would put the NHC in a bad position if a ship sinks because of a tropical system that was not classified, so more of a marine issue than anything...

Frank

[Macrocane]

Am I the only one who thinks it has become better organized in the past couple of hours? With the increase in convection and the data from the recon I think it has a chance to be upgraded.

[KWT]

That would make sense djones given what we've all been looking at. If there is alack of a solid LLC I think the NHC will hold back on an upgrade even though winds do clearly support a TS...

Or they may just assume there is a center in there somewhere and upgrade anyway thinking it maybe just a brief issue and any LLC will redevelop soon. Who knows though!

[Macrocane]

WHat a bout the radar? It could be helpful to see if there is a LLC.

[Thunder44]

Recon just found some NNW winds.

[djones65]

Latest recon found NNE winds near 24.8N and 97.1W. There appears to be a very broad circulation center with a flat pressure gradient more than 50 miles wide from near the Mexican coast northeastward. Lowest pressures extrapolated thus far was 1007 mb. I personally believe this system still has a circulation and it has not dissipated yet, but like KWT stated the center may still "tighten" up a bit in a few hours as the western edge of the broad "pressure center" impinges on the coast. Even if there is not a well defined center of circulation there appears to be in my opinion a rather broad area (45-50 miles) of tropical storm force winds based on SFMR measurements 35 to 40 knots that will presumably still have to move onshore as the depression continues inland over the next several hours. I hope my post made sense...

This is not official information, please see official advisories from NHC for latest information.

[Air Force Met]

Latest recon found NNE winds near 24.8N and 97.1W. There appears to be a very broad circulation center with a flat pressure gradient more than 50 miles wide from near the Mexican coast northeastward. Lowest pressures extrapolated thus far was 1007 mb. I personally believe this system still has a circulation and it has not dissipated yet, but like KWT stated the center may still "tighten" up a bit in a few hours as the western edge of the broad "pressure center" impinges on the coast. Even if there is not a well defined center of circulation there appears to be in my opinion a rather broad area (45-50 miles) of tropical storm force winds based on SFMR measurements 35 to 40 knots that will presumably still have to move onshore as the depression continues inland over the next several hours. I hope my post made sense...

This is not official information, please see official advisories from NHC for latest information.

I agree. Looking at BRO radar it appears to me that the real circulation is about 120 miles SE of BRO and that the NHC has ID'd a vortex. They will probably have to relocate their position.

[tolakram]

[cperez1594]

The LLC can been seen in the Radar loop. It is Southeast of Brownsville about 120 miles. It slowing getting it act together trying to push for a TS

[Macrocane]

Thanks for the radar! It doesn't look that bad actually, TS Danny last year looked worse, but at the end it doesn't matter if the NHC decide to keep it as a TD or upgrade it, the rains could be very dangerous for that area and they should be prepared.