Alex Becomes a Hurricane

By: Dr. Jeff Masters , 2:57 AM GMT on June 30, 2010

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Hi, Dr. Rob Carver filling in for Jeff on the late shift.

430AM EDT Update
The 400AM EDT advisory package has hit the wires. Alex' center of circulation is located at 23.3N, 95.1W, which is 175 miles east of La Pesca, MX and 235 miles southeast of Brownsville, TX. Alex is responding to a weakness in the ridge to it's north, the storm motion has shifted to WNW at 7 mph. The winds are unchanged from the 100AM advisory, they are still 80 mph. However, Alex continues to deepen it's pressure, the minimum central pressure is 961 mb. Hurricane force winds now extend to 30 miles away from the center, and tropical force winds extend to 200 miles from the center. Alex is currently over warm ocean waters and under weak vertical shear, so the winds are forecast to increase. However, given the strength of Alex's central pressure, there is a small possibility of a rapid intensification of an additional 35 mph.

I haven't changed my risk assessment with this advisory. Flooding from rain still remains the greatest hazard posed by Alex. Tropical storm force winds are expected to reach the coast later this morning. People should plan on finishing their outdoor preparations by this time.

150 AM Update As of the 100AM EDT advisory, Alex is at 23.1N, 94.8W. The minimum central pressure is 972 mb, and the winds have increased to 80 mph. Alex is slowly moving westwards at 5 mph in an "erratic" fashion.

As of the 11PM EDT advisory, NHC has upgraded Alex to a hurricane with maximum winds of 75 mph and a minimum central pressure of 973 mb. Alex's center is at 23.1N, 94.8W, which is 255 miles south of Brownsville, TX and 195 miles east-southeast of La Pesca, MX. Alex is moving westwards at 9 mph. Alex is expected to slightly alter it's course to the WNW before making landfall south of the Rio Grande. The winds are also forecast to pick up to 90 mph before landfall. In any event, mandatory evacuation orders have been issued for recreational vehicles and other high-profile vehicles in county parks on South Padre Island. A voluntary evacuation is in place for residents of South Padre Island and Port Isabel.

Threat from storm surge
NHC is forecasting a 3-5 foot storm surge north of the eye as Alex makes landfall.

Threat from wind
NWS forecasters expect that damage from Alex's winds will be limited to the southern counties of Cameron, Willacy, and Hidalgo. Hurricane force winds extend 15 miles from the storm center, but tropical storm force winds extend 175 miles from the center. This is a rather large circulation. The Storm Prediction Center is monitoring southern Texas for the threat of tornadoes in the outer rainbands as Alex makes landfall. I'd expect a tornado watch to be issued around noon CDT.

Threat from rain
This is the most significant impact from Alex. Rainfall totals of 6 to 12 inches are expected over northern Mexico/southern Texas with 20 inches possible in some locations. There will be flooding from this storm. If more than 5 inches fall in 6 hours, there will likely be flash flooding. The NWS office in Brownsville is advising people who were flooded out by Dolly in 2008 to evacuate to higher ground now.


Satellite-derived rainfall estimates for Alex's passage over the Yucatan peninsula on June 28, 2010. Data provided by the Climate Prediction Center.

Alex is the first Atlantic June hurricane since 1995's Allison. The storm tally for that season was 19 named storms, 11 hurricanes, and 5 major hurricanes. It will be interesting to see how this season compares to 1995.

Next update
I'll have an update Wednesday evening/night. Jeff will have an update sometime tomorrow morning.

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Quoting Claudette1234:
Corpus Christi and Brownsville local thunderstorm in radar.
Alex will create a lot of flooding concerns in this area today and even beyond as this is a big storm.
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1040. xcool
alexhurricane1991 .crazy storms
Member Since: September 26, 2009 Posts: 2 Comments: 15620
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Quoting xcool:
alexhurricane1991 storms like to follow weaks in steering patterns i lean that along time...imo.
Know i know that and that is whats happening but i think soon the weakness will close and alex will go west again. just my opinion.
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Corpus Christi and Brownsville local thunderstorm in radar.
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1036. Hhunter
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1035. xcool
alexhurricane1991 storms like to follow weaks in steering patterns i lean that along time...imo.
Member Since: September 26, 2009 Posts: 2 Comments: 15620
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doublepost?
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1032. Hhunter
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1031. Hhunter
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Quoting xcool:
alexhurricane1991 .i had that feel was go happens.bad news .imo
well if it keeps going in the same motion that its on which i doubt then it will make landfall close to the border and brownsville wont have a good day.
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Quoting victoriahurricane:
Well Levi likes Bastardi, so he must be somewhat good.

Because both are quiet flat when it comes to climate.
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1028. xcool
alexhurricane1991 .i had that feel was go happens.bad news .imo
Member Since: September 26, 2009 Posts: 2 Comments: 15620
1027. Hhunter
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Quoting xcool:
alexhurricane1991 yeah.
this was unexpected that now theres a more northerly direction to him but this should flatten out or at least i hope so
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Very strong rain band over Brownsville right now... the rain from this system is going to be horrible in places in Texas and Mexico, no matter where it makes landfall. :-(

Jo
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1024. Michfan
Bastardi is alot better than people give him credit for.
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Well Levi likes Bastardi, so he must be somewhat good.
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1022. xcool
alexhurricane1991 yeah.
Member Since: September 26, 2009 Posts: 2 Comments: 15620
cha!!me...bout 30m N of Brownsville, 8m inland....
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It's 2:30 and I have to be up in the morning... I'll be back as I can tomorrow.... Orders day, so not as much free time at work to watch the hurricane. Everyone stay safe and take care!
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Quoting xcool:
joe b naill it
Yep he is better than a lot of people give him credit for.
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1018. Hhunter
heather on twc is a twit
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1017. xcool
PensacolaDoug so true.
Member Since: September 26, 2009 Posts: 2 Comments: 15620
JB nailed it from a week away.
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I actually got some Alex caused rain this morning at 4am in West Palm Beach. Woke me up.

Good luck to our Mexico and Texas friends today.
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1014. FFEMTRQ
I'm in SWLA, it's just kicking off here, light rain for now.
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1013. xcool
joe b naill it
Member Since: September 26, 2009 Posts: 2 Comments: 15620


Anybody here actually sitting under all that precip right now?
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Quoting BahaHurican:
Wow. Entire TX coast currently experiencing some rainy / cloudy effects from Alex....
yep its a huge storm
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we all remember how fast Katrina exploded into a cat 5 and reached >175mph eerily similar...of course not practical with Alex...
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1009. FFEMTRQ
Thank you Michfan
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1008. Hhunter
bastardi

BANG!! ALEX PRESSURE CRASHES.

A great example of my rapid deepening ( feedback) syndrome. Absolutely dead on and something that if you are a student of this you should log away. Pressures are already down to near 960 mb and I may have been conservative in the idea , though I did say at least 960 mb. (High density recon has 959.6 now)

TPC has shifted the storm track south to the idea I had.. A word of advice to them, this will get the wind it should have once it nears the coast as the frictional effect tighten the eye. How many times have we seen that? They should predict the ramp up of wind that goes with the pressure here.

A good demonstration of how to beat the models... and the experts and if you were reading along with this, you could see the points I was making and so in future storms, you can practice yourself. We should see several of these this year, and its early, so even if this hits 950 mb it probably wont be the most graphic example.

At 960 mb, the pressure ranks this has a 3, but at 85 mph its a 1.5 with wind. This gives us a 4.5 The tightening of the storm because of the low pressure and frictional considerations as it nears the coast means that in its current state, the storm should have winds of 100-110 mph at lanfall, and that is what this scale shows you... the major hurricane starts at 6 . Since pressures may wind up near 950 mb, this should be strong 2 or 3 ( divide in half the total if you want to go back to that) when it hits.


It is early, I have been up all night though.. so I cant decide if its late.

By the way.. the GFS is too cool with the warm up. Then again, you probably knew that given the way this year has gone with that model



ciao for now *****
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1007. xcool
sarahjola i try alot
Member Since: September 26, 2009 Posts: 2 Comments: 15620
wow! thanks xcool. i am going to bed now just in case i need to do some prep. tomorrow. good night, or good morning all. thanks for all the info x, your awesome!
Member Since: September 10, 2008 Posts: 0 Comments: 1291
Wow. Entire TX coast currently experiencing some rainy / cloudy effects from Alex....
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1004. Michfan
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In the long range Radar from Brownsville we can see center of the hurricane at 23º20'N 95ºW
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1002. FFEMTRQ
Does anyone have a link to current steering map?
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1001. xcool
BIG STORMS notgood for steering patterns...
Member Since: September 26, 2009 Posts: 2 Comments: 15620
Morning all.

Stewart on the discussion is very clear and concise as usual.

Alex on Navy website:

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Quoting Hhunter:
that is not a surface wind...that is showing you wind down through the column of air..is a clue that more wind could be a coming. thus one of reasons hinted to by the excellent stacey stewart in his nhc update.
Who is the best in my opinion.
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998. xcool
sarahjola from tx sw LA .ANYTHING CAN HAPPEN FAST .
Member Since: September 26, 2009 Posts: 2 Comments: 15620
track not affecting strength..steering patterns affecting track environment conditions and structure improve over time impacting strength
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Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 30th day of the month at 08:51Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)
Storm Number & Year: 01L in 2010
Storm Name: Alex (flight in the North Atlantic basin)
Mission Number: 11
Observation Number: 05
A. Time of Center Fix: 30th day of the month at 8:42:00Z
B. Center Fix Coordinates: 23°19'N 95°00'W (23.3167N 95.W)
B. Center Fix Location: 239 miles (384 km) to the SE (139°) from Brownsville, TX, USA.
C. Minimum Height at Standard Level: 1,075m (3,527ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 71kts (~ 81.7mph)
E. Location of the Estimated Maximum Surface Wind: 7 nautical miles (8 statute miles) to the NE (45°) of center fix
F. Maximum Flight Level Wind Inbound: From 123° at 82kts (From between the ESE and SE at ~ 94.4mph)
G. Location of Maximum Flight Level Wind Inbound: 10 nautical miles (12 statute miles) to the NE (45°) of center fix
H. Minimum Sea Level Pressure: 961mb (28.38 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 19°C (66°F) at a pressure alt. of 1,522m (4,993ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,520m (4,987ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 19°C (66°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the south
M. Eye Shape & Diameter: Circular with a diameter of 10 nautical miles (12 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Flight Level Wind: 82kts (~ 94.4mph) in the northeast quadrant at 8:33:40Z
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Quoting FtWaltonBch2Tucson:
Agreed, but it's very interesting to note that the dropsonde found that, they haven't seen anything near that strong at flight level...


Can't really argue with that; it's certainly an ominous reading.
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that is not a surface wind...that is showing you wind down through the column of air..is a clue that more wind could be a coming. thus one of reasons hinted to by the excellent stacey stewart in his nhc update.
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xcool- we live around the same area, you worried about it for us or for maybe central tx?
Member Since: September 10, 2008 Posts: 0 Comments: 1291
Question, what would a significantly stronger storm (as the pressure drop seems to indicate may be happening soon) do to the track??
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Quoting JVGazeley:


No, that's at altitude. It's the 89mph that's a better indication.
Agreed, but it's very interesting to note that the dropsonde found that, they haven't seen anything near that strong at flight level...
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.