ATL: INVEST 95L - DISCUSSION

[brunota2003]

DOPPLER RADAR indicates maybe TS winds? The nearest Doppler is 110 miles away looking at a height of 12,500 feet above the low. There are plenty of surface obs around the weak low that indicate 15-20 kts (one 25kt wind in a squall). And winds W-NW of the low are blowing AWAY from the center. I could see calling it the mini TD it's been for 24 hours now, but a TS??

http://myweb.cableone.net/nolasue/95Lg.gif

Actually, looking at that map...is there even a closed surface circulation? There is a ESE wind of 15 knots where there should be a wind coming from the NE or even NNE. Sharp trough on the surface perhaps, but that seems to point toward the low NOT being entirely closed off at the surface.

[hurricanefloyd5]

this should be bonnie now !!!!!!!!!!!!!!!!!!

[ConvergenceZone]

I agree Ivanhater .

I mean, how do you go from 0 percent(which is null in regards to chances) to 60% just like that. That's the part that bothers me.

[Cainer]

This ASCAT pass is interesting. Winds of at least 35 MPH are occurring in the southern half of the circulation, so one could argue that as winds are typically stronger in the NE portion of a storm that perhaps this does have TS force winds.

[Ivanhater]

ASCAT shows 40 mph winds

[hurricanefloyd5]

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

and we have landfall

[Stormcenter]

Hmmmm what's old duck saying?


http://www.rap.ucar.edu/weather/satelli ... uration=12

[Ptarmigan]

If it developed, it would be a very small system, like Marco or Humberto (2007).

[djones65]

Cycloneye, I personally agree with you... However, the fact that only a special tropical weather outlook was issued instead tells me that Stacy Stewart has "lost" his argument to upgrade. I can see a scenario in which Stewart thought this deserved an upgrade and his colleagues disagreed. If he was going to have won the argument then I believe a special advisory would have been written instead. This way, persons in vicinity of Houma, LA and Vermillion Bay can be warned of possible tropical storm conditions without having to initiate advisories on a system that will be inland within 12 to 18 hours at the very most. Plus, I personally believe that 96L will be a much more significant player later this week and affect areas very similar to where 95L came ashore. I personally do not see a strong ridge building in and 96L may track into central Louisiana by the end of this week. This system in my opinion makes two tropical depressions that have gone unclassified this season, and three this year if you count the February tropical storm near Portugal. 92L was a likely depression in middle June east of the islands, and a buoy about 350 miles east of Martinique reported 32 knot sustained winds outside of heavy convection AFTER the system was beginning to weaken significantly. Drezee I believe suggested that one could make a case that arguably 92L had briefly attained tropical storm force winds. And now, 95L, which has been in my opinion a tropical cyclone for 36 hours now. I believe it reached depression stage yesterday morning. The NHC I believe didn't necessarily "screw up," but I believe they rushed to judgement like many of the posters on S2K that this system wasn't going to develop and then yesterday, on a Holiday, unexpectedly flared up and it was rationalized that the system would be inland soon so no need to initiate advisories. Anyway, that's just my opinion... Does anyone else agree? I think NHC does an outstanding job, but these "micro" systems are difficult to figure out how to classify them. I know in 2008, there was still lots of disagreement on naming Marco in the Bay of Campeche. Some felt it didn't deserve classification due to its tiny size. Based on a conversation with a friend of mine who works there and we went to school at FSU together.

[KWT]

I think odds are this maybe upgraded after season, though I bet the NHC are tempted to upgrade it right now like they did when Arthur was upgraded...

Reminds me alot of the Invest that made landfall last year that was pretty much a TS.

[Cryomaniac]

The following is the opinion of Cryomaniac, and is not based on any evidence, meteorological or otherwise. As such it should not be used for any purpose

I think it's possible that they will upgrade it now, but I don't think it's likely. Most likely they'll wait till post season.

[tailgater]

I'm of the opinion that the LLC is still a tad SW of that MLC moving on shore now and most of the weather will be with that MLC. as it will all be on shore in a few hours.

[Weatherfreak000]

This is no question a Tropical Cyclone. It should be named Bonnie.

[wxman57]

Wxman57, 12,500 feet, wouldn't that be similar to a recon plane at 700 mb or 10000 feet? Using a .90 conversion factor, or even a .85 would be an accurate way to measure potential surface winds. If the Doppler velocities were 40 knots or so then surface winds could reasonably be estimated at 34 knots. This storm is a very small compact system. We have a large network of ship, buoys, and oil platforms offering observations, but relative to the size of the circulation and the area being affected, they are still few and far between. If this was a larger circulation then I would agree that the surface obs do not substantiate a storm, but this is a tiny system and I believe it is possible for much stronger winds to exist near the center where no obs are being made. Even in your satellite and observation graphic, there were only 7 surface obs being utilized over an area in excess of 200 miles. That is a lot of "holes" for stronger winds to be observed. With all that being said, I thought this system was a tropical storm yesterday very similar to Marco of 2008 which many others posted similar thoughts. Today it is not as well organized but I definitely think it is a tropical depression, and I would not at all be surprised if tropical storm force winds were observed around the center especially to the east.

The quote stated that Doppler radar indicated winds near TS force, not over. That would put surface winds at a max of 25-30 kts, which is what one ship reported (25 kts). There are plenty of other obs in the stronger wind region of the low, and 25 kts is the max. Could be a 30kt wind offshore in the squall. But there is no evidence that this is a TS.

NHC just issued model guidance as a disturbance with 30 kt winds. If they were going to classify it, it would not be called an invest on the guidance.

[Cryomaniac]

This is no question a Tropical Cyclone. It should be named Bonnie.

The problem,of course, is that the NHC don't agree, and they are the one's who matter (without wishing to restart the "It's not a tropical cyclone unless the NHC say so" debate from I believe '06).

[Macrocane]

Maybe in the post season analysis they will upgrade it to TD or TS, in that case this would be the 2nd tropical cyclone of the season.

[wxman57]

ASCAT shows 40 mph winds

http://manati.orbit.nesdis.noaa.gov/asc ... MBds13.png

I see a couple 25 kt winds and two 30 kt wind barbs in that image. Surface obs are indicating 25 kts. There are no observations supporting TS winds. Could have called it a TD 24 hours ago, though a very tiny one. Data do suggest it was a TD.

[Stormcenter]

Here is a nice radar loop of 95L.


http://radar.weather.gov/radar.php?rid= ... 1&loop=yes

[brunota2003]

Wxman57, 12,500 feet, wouldn't that be similar to a recon plane at 700 mb or 10000 feet? Using a .90 conversion factor, or even a .85 would be an accurate way to measure potential surface winds. If the Doppler velocities were 40 knots or so then surface winds could reasonably be estimated at 34 knots. This storm is a very small compact system. We have a large network of ship, buoys, and oil platforms offering observations, but relative to the size of the circulation and the area being affected, they are still few and far between. If this was a larger circulation then I would agree that the surface obs do not substantiate a storm, but this is a tiny system and I believe it is possible for much stronger winds to exist near the center where no obs are being made. Even in your satellite and observation graphic, there were only 7 surface obs being utilized over an area in excess of 200 miles. That is a lot of "holes" for stronger winds to be observed. With all that being said, I thought this system was a tropical storm yesterday very similar to Marco of 2008 which many others posted similar thoughts. Today it is not as well organized but I definitely think it is a tropical depression, and I would not at all be surprised if tropical storm force winds were observed around the center especially to the east.

The quote stated that Doppler radar indicated winds near TS force, not over. That would put surface winds at a max of 25-30 kts, which is what one ship reported (25 kts). There are plenty of other obs in the stronger wind region of the low, and 25 kts is the max. Could be a 30kt wind offshore in the squall. But there is no evidence that this is a TS.

NHC just issued model guidance as a disturbance with 30 kt winds. If they were going to classify it, it would not be called an invest on the guidance.

Strongest I saw was around 25 knots, just browsing through the various buoy obs...another thing is, is the low even closed on the surface? I cannot completely close off a circulation on the surface using the buoy data...there is only light and variable winds on the W/NW side of the system.

[Steve]

Not sure if it will play, but here's a video I took when the only wrap-around band we're likely to get came through. It's still rumbling a little outside and drip dropping, but it was the typical dark band, some wind, light raindrops and then heavier rain progression. Not sure if it worked because my phone camera is screwed up, but I guess I'll know once i hit the "submit" button.

http://www.youtube.com/watch?v=_itd1lIbyLw