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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Yeah, Alex looks to be drifting towards the NW. Still a ways to go for landfall.
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1340. Skyepony (Mod)
I'm shocked the temp difference inside & outside the center isn't greater.
Member Since: August 10, 2005 Posts: 162 Comments: 37779
I'll be back later.
Member Since: August 19, 2006 Posts: 0 Comments: 15798
For you education minded...a lurker question:
What would it take for Alex to become Estelle?
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STEADY STRENGTHENING RIGHT UP UNTIL LANDFALL SEEMS
REASONABLE. HOWEVER...GIVEN THE RELATIVELY LOW CENTRAL PRESSURE
RECENTLY MEASURED BY THE RECON AIRCRAFT...RAPID INTENSIFICATION OF
AT LEAST 30 KT IN 24 HOURS IS A DISTINCT POSSIBILITY. THE OFFICIAL
INTENSITY FORECAST IS A BLEND OF THE LGEM AND SHIPS MODELS.

STEADY STRENGTHENING RIGHT UP UNTIL LANDFALL SEEMS
REASONABLE. HOWEVER...GIVEN THE RELATIVELY LOW CENTRAL PRESSURE
RECENTLY MEASURED BY THE RECON AIRCRAFT...RAPID INTENSIFICATION OF
AT LEAST 30 KT IN 24 HOURS IS A DISTINCT POSSIBILITY.
THE OFFICIAL
INTENSITY FORECAST IS A BLEND OF THE LGEM AND SHIPS MODELS.

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1336. Asta
Quoting StormW:
Hot off the press!

HURRICANE ALEX SYNOPSIS JUNE 30, 2010 ISSUED 8:55 A.M. EDT

Thanks Storm!
Member Since: July 4, 2008 Posts: 30 Comments: 1024
Quoting kmanislander:


That ridge is losing the battle to hold it down. A deepening system like Alex wants to go poleward.


The Sierra Madre mountains might be deflecting him north, too.
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1334. KEEPEROFTHEGATE (Mod)
772

URNT12 KNHC 301242 CCA

VORTEX DATA MESSAGE AL012010

A. 30/12:12:10Z

B. 23 deg 32 min N

095 deg 12 min W

C. 850 mb 1052 m

D. 56 kt

E. 217 deg 8 nm

F. 300 deg 62 kt

G. 217 deg 8 nm

H. 958 mb

I. 20 C / 1525 m

J. 22 C / 1520 m

K. 19 C / NA

L. OPEN NW

M. C9

N. 12345 / 8

O. 0.02 / 1 nm

P. AF306 1101A ALEX OB 15 CCA

MAX FL WIND 89 KT NE QUAD 12:35:50Z

MAX OUTBOUND FL WIND 89 KT NE QUAD 12:35:50Z

MAX OUTBOUND AND FL WIND 89 KT NE QUAD 12:35:50Z

;
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Alex appears to be drifting NW or even NNW.
Member Since: June 29, 2009 Posts: 13 Comments: 5311
1332. jpsb
Quoting beeleeva:
Anyone along Galveston Bay-Seabrook area hearing of tidal flooding yet?? Winds appear to be up from Sailflow readings at Seabrook Sailing Club....Concerned about sailboats at SSC and HYC....
Galveston Bay here, San Leon, tide is up about 3 feet. Nothing serious yet.
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Quoting DestinJeff:


hey Nrti, that isn't too reassuring. or am i supposed to think it is? looks to me like very weak and far removed influence in mid level, and significant influence in not such a good way at high level.


Thats why I said a little, however the high level is just starting to come in to play, per the CIMSS categories.
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1330. angiest
Quoting jpsb:
It is blowing pretty good (15-20 mph) here on Galveston Bay and we are what 6, 8 hundred miles away? Sure would hate to be any closer.


In Katy before I went to work this morning we had a decent breeze out of roughly the NE.
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Quoting beeleeva:
Anyone along Galveston Bay-Seabrook area hearing of tidal flooding yet?? Winds appear to be up from Sailflow readings at Seabrook Sailing Club....Concerned about sailboats at SSC and HYC....


I'm in the area.. so far I have not heard anything.
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Quoting Orcasystems:
North of track... tracking NW, not going anywhere in a hurry.



AOI


That ridge is losing the battle to hold it down. A deepening system like Alex wants to go poleward.
Member Since: August 19, 2006 Posts: 0 Comments: 15798
1327. Skyepony (Mod)
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 30th day of the month at 12:42Z
Corrected: This observation corrected a previous observation.
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)
Storm Number & Year: 01L in 2010
Storm Name: Alex (in the North Atlantic basin)
Mission Number: 11
Observation Number: 15
A. Time of Center Fix: 30th day of the month at 12:12:10Z
B. Center Fix Coordinates: 23°32'N 95°12'W (23.5333N 95.2W)
B. Center Fix Location: 219 miles (353 km) to the SE (139°) from Brownsville, TX, USA.
C. Minimum Height at Standard Level: 1,052m (3,451ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 56kts (~ 64.4mph)
E. Location of the Estimated Maximum Surface Wind: 8 nautical miles (9 statute miles) to the SW (217°) of center fix
F. Maximum Flight Level Wind Inbound: From 300° at 62kts (From the WNW at ~ 71.3mph)
G. Location of Maximum Flight Level Wind Inbound: 8 nautical miles (9 statute miles) to the SW (217°) of center fix
H. Minimum Sea Level Pressure: 958mb (28.29 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 20°C (68°F) at a pressure alt. of 1,525m (5,003ft)
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 northwest
M. Eye Shape & Diameter: Circular with a diameter of 9 nautical 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: 89kts (~ 102.4mph) in the northeast quadrant at 12:35:50Z
Maximum Flight Level Wind Outbound: 89kts (~ 102.4mph) in the northeast quadrant at 12:35:50Z
Maximum Wind Outbound: 89kts (~ 102.4mph) in the northeast quadrant at 12:35:50Z
Maximum Flight Level Wind: 89kts (~ 102.4mph) in the northeast quadrant at 12:35:50Z
Member Since: August 10, 2005 Posts: 162 Comments: 37779
Cyclone Oz broadcasting live near Brownsville. Going to Mexico to intercept Alex in a fishing village. Go HERE
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1324. angiest
Quoting Claudette1234:
on the radar of Brownsville Long range is moving north.

Latest position is 23,6N 95,2W


Watching in grlevel3 from the Brownsville radar. It does look more northerly for now. But still so far on the edge of the radar it is hard to tell for sure. Still well out of range of velocity scans.
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1323. Buhdog
The NWS radar to me either shows a system either jogging north or the coc just expanded giving the appearance of a northerly component. AWESOME we now have an eye to track! Cirrus clouds in ft myers this morning... I smell storms later.
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NW drift, he doesnt wanna go to Mexico, he wants to go north, and as big as he is he might be able to overpower the ridge in the long haul

Member Since: July 14, 2008 Posts: 1 Comments: 9628
Quoting AstroHurricane001:


Alex could be blocked by the mountains of Mexico, and it could stall after making landfall. The part over over water would continue to intensify and dump convective moisture over Mexico, Texas and Louisiana, then the storm could drift northeastward over Texas, become blocked by the high and turn extratropical, dumping floodwaters over the Mississippi River and southern Louisiana, then drift northwest around the high and plough into Southern Ontario while colliding into a cold front and dumping rain there. That could alleviate drought in some places, but it would be a disaster even for me if my scenario pans out.


we are getting water dumped on us in fla panhandle too!Link
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1320. Asta
Quoting AstroHurricane001:


Alex could be blocked by the mountains of Mexico, and it could stall after making landfall. The part over over water would continue to intensify and dump convective moisture over Mexico, Texas and Louisiana, then the storm could drift northeastward over Texas, become blocked by the high and turn extratropical, dumping floodwaters over the Mississippi River and southern Louisiana, then drift northwest around the high and plough into Southern Ontario while colliding into a cold front and dumping rain there. That could alleviate drought in some places, but it would be a disaster even for me if my scenario pans out.
You explained my concerns exactly. Let's hope Alex heads inland.
Member Since: July 4, 2008 Posts: 30 Comments: 1024
Good morning! Just coming out of lurking (hesitantly) because this has been the most fascinating storm to track. Each morning I wake up to a new set of conditions to learn the effects of on the storm. I wonder if all our storms this year will take us to school like this one has and I don't think Alex is done with us quite yet!
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Guys, one doubt. If in my local forecast they're expecting strong winds from the NW, then N, then NE, E, ESE. The eye will be passing south or north of my location? Thanks!
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1316. aquak9
RainmanWeather 3D Radar links, from Brownsville, in Rainman32's blog.
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Quoting yonzabam:
What took you so long, Alex?




The sheer size is inhibiting rapid intensification, but NHC says it could strengthen to a cat. 3.
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Quoting mrsalagranny:
Oh my Alex needs to go on and make landfall.That sort of scenario doesnt need to pan out.Would be horrible for the oil spill.


Alex could be blocked by the mountains of Mexico, and it could stall after making landfall. The part over over water would continue to intensify and dump convective moisture over Mexico, Texas and Louisiana, then the storm could drift northeastward over Texas, become blocked by the high and turn extratropical, dumping floodwaters over the Mississippi River and southern Louisiana, then drift northwest around the high and plough into Southern Ontario while colliding into a cold front and dumping rain there. That could alleviate drought in some places, but it would be a disaster even for me if my scenario pans out.
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on the radar of Brownsville Long range is moving north.

Latest position is 23,6N 95,2W
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North of track... tracking NW, not going anywhere in a hurry.



AOI
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1310. RickWPB
Someone asked about knots to statute mile conversion. Just multiply knots by 1.15 to get the the statute mile speed.

Nautical mile = 6080 ft
Statute mile = 5280 ft
_______________________

6080 / 5280 = 1.15151515151515151
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Anyone along Galveston Bay-Seabrook area hearing of tidal flooding yet?? Winds appear to be up from Sailflow readings at Seabrook Sailing Club....Concerned about sailboats at SSC and HYC....
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Quoting DestinJeff:

Click pic to enlarge

please help me find upper-level winds that are serving as the westward steering influence for Alex. thanks,


A little indication in the mid level water vapor.


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Good morning everyone!:)

Long time blogger here who is rarely able to find time to post anymore. That being said, I did have a couple minutes to spare this morning and wanted to comment on the large disparity between the central pressure of Alex and his corresponding MSW.

How can this happen?

1) We all know that wind itself is simply air in motion and its intensity is determined by the difference in pressure over a given distance. This is referred to as the "pressure gradient". The steeper the pressure gradient, the stronger the force of the wind. In TC's, this wind-pressure relationship is typically determined by the corresponding "pressure gradient" between the minimum central pressure of the COC and the outer-most isobar. It can also be determined based upon the storms radius of maximum winds as well.

2) In the case of hurricane Alex, the distance between its COC (eye) and its outer-most isobar is VERY large. Thus, the difference in MSLP between these two points cover a MUCH larger area (distance) and doesn't correlate to a MSW one might expect with an average size storm.

3) It is also important to consider the environmental (ambient) SLP within which it is embedded. This too can alter the typical wind-pressure relationship for a particular TC with all things being equal. Simply put, a lower ambient MSLP will also require a lower than normal central pressure within a TC in order for it to generate the same MSW-with all other factors being equal.

4) Alex is still not a very well organized storm at the moment (although its getting there) despite its very low central pressure. As it continues to get better organized, its MSW will increase and start to catch up to its abnormally low B.P.-outside of the typical "lag-time" between a drop in central pressure and a corresponding increase in surface winds.

Historical Perspective:

At 10 pm CDT on September 10, 2008, there was a VERY large hurricane moving northwestward through the south central Gulf of Mexico. It's name was "Ike". At the time, it's minimum central pressure was recorded at 944 mb. This pressure reading would typically correspond to a MSW of roughly 130-135 mph (category four intensity). However, its enormous size offset the typical wind-pressure relationship and the corresponding "pressure gradient" could only generate a MSW of 100 mph.

By the time hurricane Ike made landfall around 210 am CDT on September 13, its organization had improved significantly. As a result, it crossed the shoreline as a 110 mph category two hurricane with a minimum central pressure of 952 mb. It is important to note that an average size storm with a 952 mb B.P. would've typically generated a MSW of roughly 125 mph.

I wish I had time to elaborate further, but I really have to get going. Anyway, I hope this post will have been beneficial to some. More importantly, I want to wish each and everyone of you a good and safe rest of the day!:)

Most sincerely,
Tony
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What took you so long, Alex?


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TWC just mentioned latest data Alex dropped 1mb and now shows 958
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1303. 7544
Quoting DestinJeff:


worst case scenario would be Alex doesn't get to land with the steering influence of the weak high. Sw flow out in front of a trough and/or weakness in the atlantic high results in more of a northerly component, followed by NNE, NE, etc ...

Alex just needs to make landfall before these other elements begin to factor in more and more.


thanks so if he stalled this could come into play hmmmm interesting. thanks again will be watching
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Quoting DestinJeff:


worst case scenario would be Alex doesn't get to land with the steering influence of the weak high. Sw flow out in front of a trough and/or weakness in the atlantic high results in more of a northerly component, followed by NNE, NE, etc ...

Alex just needs to make landfall before these other elements begin to factor in more and more.
Oh my Alex needs to go on and make landfall.That sort of scenario doesnt need to pan out.Would be horrible for the oil spill.
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1301. RickWPB
Steering layer:

Layer Mean Wind - West Atlantic
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1299. soloco
Quoting whipster:
Doubt if the Mexican Army lets Oz through. They will blockade every road toward the beaches. Does he have an escort?


I just crossed the border into Reynosa.....the friggin teenage soldiers were all hunkered down under an awning.......zero vehicle inspection. I think OZ will be OK!
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Member Since: September 22, 2005 Posts: 11 Comments: 2032
Recon finding 957 mb pressures. Unbelievable.
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1294. Asta
LINK

Call me a fool, but I still don't see how this system will move inland- rather then follow the movement of the moisture NE.. even if it does move inland.. it sure appears that it will dump a whole lot of moisture on S.LA
Member Since: July 4, 2008 Posts: 30 Comments: 1024
1293. jpsb
Quoting kmanislander:
Good Morning

I see that the weak steering regime from last night is still a problem. This has really been a fascinating scenario to watch unfold. The weakness between the two highs has still not filled although some slow progress towards land continues.
It is blowing pretty good (15-20 mph) here on Galveston Bay and we are what 6, 8 hundred miles away? Sure would hate to be any closer.
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1292. Asta
Member Since: July 4, 2008 Posts: 30 Comments: 1024
1291. 7544
Quoting DestinJeff:


I am tracking, KMan, trust me. I saw that CIMSS before anything else this morning I knew soemthing was up. That is why I am anxious for the 1200s.

If Alex takes on a more northerly component then that increases his time over water, which in turn increases the time for the next trof to move east ... with its sw flow out in front.


if this does happen then will this nudge alex in what way tia
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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.

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