Tropical Storm Don forms in the Gulf of Mexico
Tropical Storm Don, the fourth tropical cyclone of the 2011 season, has formed in the Gulf of Mexico just north of the Yucatan Peninsula. Hurricane Hunters began investigating the system earlier this afternoon and quickly found a closed surface circulation. As the mission continued to gather data from what was thought to be a tropical depression at the time, winds of around 39 mph were found, as well as a 1001 mb central pressure, bringing the system up to tropical storm strength.
Figure 1. Satellite loop of Tropical Storm Don. This loop will stay current.
The official forecast for Don agrees with what most of the models have been suggesting over the past 24 hours. Don will make its way toward the northwest over the next 48 hours before making landfall somewhere between Brownsville and Galveston. The statistical models tend to suggest a more southerly track toward Brownsville, and the dynamical models are forecasting anything from Corpus Christi to Galveston. They all tend to agree landfall will occur late on the 29th (Friday night). Whether or not Don will reach hurricane status is still in question. The Hurricane Center's initial forecast is that Don will remain a tropical storm until landfall. Today some models were intensifying Don to a strong tropical storm, but none crossed the hurricane threshold. Now that we have data from aircraft reconnaissance, the models will be able to get a better handle on potential intensity. The runs that occur later tonight and early tomorrow will have much less uncertainty than those from today.
Figure 2. Model forecast tracks for Tropical Storm Don as of Wednesday afternoon.
I believe Jeff will be back tomorrow for an update.
Angela
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Level Wind Direction Wind Speed
1003mb (Surface) 155° (from the SSE) 32 knots (37 mph)
995mb 160° (from the SSE) 50 knots (58 mph)
991mb 160° (from the SSE) 53 knots (61 mph)
953mb 170° (from the S) 51 knots (59 mph)
941mb 165° (from the SSE) 45 knots (52 mph)
882mb 160° (from the SSE) 49 knots (56 mph)
843mb 155° (from the SSE) 53 knots (61 mph)
The high winds could have been from an embedded severe thunderstorm. Either that or Don is whack.
Coordinates: 23.8167N 89.2W
Acft. Static Air Press: 843.3 mb (~ 24.90 inHg)
Acft. Geopotential Hgt: 1,545 meters (~ 5,069 feet)
Extrap. Sfc. Press: 1007.8 mb (~ 29.76 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 160° at 44 knots (From the SSE at ~ 50.6 mph)
Air Temp: 17.1°C (~ 62.8°F)
Dew Pt: 4.7°C (~ 40.5°F)
Peak (10s) Flt. Lvl. Wind: 47 knots (~ 54.0 mph)
SFMR Peak (10s) Sfc. Wind: 38 knots (~ 43.7 mph)
SFMR Rain Rate: 4 mm/hr (~ 0.16 in/hr)
bad thing is there is a trough trying to recurve it. i wish the CMC bought it into the SE coast because they are in some need of rain
Transmitted: 28th day of the month at 12:10Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Storm Number: 04
Storm Name: Don (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 04
Part A...
Date: Near the closest hour of 12Z on the 28th day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 23.7N 89.4W
Location: 436 miles (701 km) to the S (175°) from New Orleans, LA, USA.
Marsden Square: 081 (About)
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1003mb (29.62 inHg) Sea Level (Surface) 26.8°C (80.2°F) 26.4°C (79.5°F) 155° (from the SSE) 32 knots (37 mph)
1000mb 27m (89 ft) 26.4°C (79.5°F) 25.9°C (78.6°F) 155° (from the SSE) 38 knots (44 mph)
925mb 716m (2,349 ft) 24.4°C (75.9°F) 21.8°C (71.2°F) 165° (from the SSE) 47 knots (54 mph)
850mb 1,458m (4,783 ft) 22.2°C (72.0°F) Approximately 11°C (52°F) 155° (from the SSE) 52 knots (60 mph)
Information About Radiosonde:
- Launch Time: 11:56Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.
Remarks Section...
Splash Location: 23.72N 89.41W
Splash Time: 11:59Z
Release Location: 23.7N 89.4W
Release Time: 11:56:58Z
Splash Location: 23.72N 89.41W
Splash Time: 11:58:58Z
Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 165° (from the SSE)
- Wind Speed: 50 knots (58 mph)
A.40 mph
B.45 mph
C.50 mph
D.55 mph
E.Higher
F.Lower
Significant Temperature And Relative Humidity Levels...
Level Air Temperature Dew Point
1003mb (Surface) 26.8°C (80.2°F) 26.4°C (79.5°F)
970mb 25.8°C (78.4°F) 22.7°C (72.9°F)
909mb 24.0°C (75.2°F) 21.2°C (70.2°F)
887mb 24.2°C (75.6°F) Approximately 17°C (63°F)
861mb 23.0°C (73.4°F) Approximately 17°C (63°F)
850mb 22.2°C (72.0°F) Approximately 11°C (52°F)
843mb 21.8°C (71.2°F) Approximately 6°C (43°F)
It is pretty dry above 850MB... once they get another drop out then it could further validate the extend of the dry air in the environment Don is in.
The SE certainly needs some rain, but be careful before wishing a long-track storm across the Atlantic towards the coast, could be more than a rain maker. A few models have suggested some development a few times, be interesting to see how it organises.
You beat me to it!
Yeah, plus it is out of radar range. It must be really tight in there.
B.
Sorry :P
trust me a cat 1 out of it wouldnt be bad although its a week and more away the ecmwf and cmc try to recurve it but funny how when don was in that EXACT same spot instead of recurving how most of the models showed, it made its way into the gulf towards texas.. interesting :)
Maybe 50mph is my guess.
No problem.
Don Dawn
Yeah, already a big pop of convection is occurring. It would seem the Yucatan is becoming less of a problem.
Levi explained this pretty well in his tidbit yesterday. Basically the high pressure is pushing convection towards the west, but there's a weakness which is pulling the surface low in Don slightly north, so Don is getting a mix of those and drifting northwest, while the convection behind Don is moving west.
4 TS in the Atlantic. No storms peaking at TS in the E-PAC
C
DON is not weaking by any means they be doing other pass
Thank you. I did watch Levi's tidbits, but no coffee for me this morning as I drive up to Arkansas. No coffee means my brain is working too hard to wake up to be able to work right. At least the Yukatan will only get a good storm and not a ts or worse. Hope it's not enough to cause more floods or slides for them.
He's not weakening now, looks like he's getting his act together, but I'd say he did weaken a little overnight. I'd expect them to find maybe 1001/1000mb at the next pass.
LinkShearMap
LinkWVLoop
I'd agree with that, he obviously had overnight troubles.
I'm guessing you meant that its pressures are slightly higher, not that his winds are lower. We'll see what the next pass shows.
Been lurking the past few days just no time to post.. will continue to check in and out as I can to see what is happenening.
Good Luck to Texas, hope they get the rain they really need.
Be good!
Correct... if you mix dry air with a TSTM(s) you get high WND speeds.
You can also see that Don is not uniform in its WND field from what I would expect to be a TS. Currently its W periphery severely lacks of any decent WND speed readings.
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