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Hurricane Dolly closes in on Texas/Mexico

By: Dr. Jeff Masters, 9:25 PM GMT on July 22, 2008

Hurricane Dolly has become the second hurricane of the 2008 hurricane season. Dolly is barely a hurricane, and is still struggling to build a complete eyewall. Visible satellite loops show an eye developing, and heavy thunderstorm activity continues to increase near the core of the storm. Dolly has good upper-level outflow to the west and north, but restricted on the south side, where an upper level low pressure system is still interfering. Maximum surface winds measured by the SFMR instrument on the current Hurricane Hunter aircraft inside Dolly were 74 mph (65 kt), measured at 4:17 pm EDT. Brownsville, Texas long-range radar shows the eyewall is complete on Dolly's west side, but is struggling to get established on the east side. Radar estimated rainfall amounts of 1/10 of an inch have fallen on the Texas/Mexico coast so far, thanks to the outermost spiral bands of Dolly.


Figure 1. Latest long-range radar image from Brownsville, Texas.

The intensity forecast
The intensification potential for Dolly remains high, but until Dolly can form a full eyewall, it won't be able to take full advantage of the favorable environment. Wind shear over Dolly is about five knots, and is expected to remain below ten knots over the next two days. An upper level high pressure system is moving into place over the storm, which should enhance Dolly's upper-level outflow and allow more rapid intensification. Dolly is over waters of 29°C. The waters cool to about 28°C by midnight tonight as Dolly approaches the coast and passes over a cool ocean eddy. The depth of the warm waters Dolly is over has decreased, and the Tropical Cyclone Heat Potential has fallen from about 40 to 20 kJ/cm**2. This decreases the potential of rapid intensification. Our skill in making intensity forecasts is poor, but it currently appears that Dolly only has enough time to intensify into a Category 1 hurricane. A Category 2 hurricane still a possibility, though. I put the chances of Dolly reaching major hurricane status (Category 3 or higher) at 1%.

The track forecast
The track forecast has changed little since this morning, with the various computer models predicting pretty much the same behavior as they did 12 hours ago. Four models are predicting a landfall in northeastern Mexico--the UKMET, ECMWF, NOGAPS, and GFS--and two models are predicting a Texas landfall--the GFDL (just north of Brownsville) and the HWRF (near Corpus Christi). Dolly could come ashore anywhere within the cone of uncertainty, and one should not assume the storm will track down the "skinny black line" NHC has drawn through their official forecast. The timing of Dolly's landfall, as predicted by the computer models, will be anywhere from 8 am - 10 pm Wednesday. However, the GFS and ECMWF hint that Dolly may stall out right by the coast Wednesday, and some slow and erratic motion is possible tomorrow before the storm finally comes ashore.

Links to follow:
Brownsville, TX long range radar
Texas marine forecasts and observations
Brownsville, TX weather
Corpus Christi, TX weather

Damage expected from Dolly
I posed the question in this morning's blog, Since hurricanes began getting names in 1950, only one major hurricane that hit the U.S. did not get its name retired. Which one was it? A hint: the track was similar to Dolly's expected track. The answer is, Hurricane Bret, which hit Padre Island National Seashore, just north of Brownsville, Texas, as a Category 3 hurricane on August 22, 1999. The park is a long barrier island with few structures and no commercial developments, and the fury of Bret's 115 mph winds were confined to desolate unpopulated seashore. Bret did $60 million in damage, mostly in the small towns just inland from the National Seashore. Bret dumped 14 inches of rain on northern Mexico, and brought an 8-10 foot storm surge to Padre Island. Several new channels were cut through the barrier island, connecting the ocean to the Laguna Madre sound behind Padre Island.


Figure 2. Evacuation zones for Category 1,2,3,4,5 hurricanes. The city of Brownsville needs to evacuate only for a Category 5 hurricane. Image credit: Texas division of emergency management.

If Dolly follows a similar path, we can expect relatively minor damage. Even if Dolly makes a direct hit on the sister cities of Brownsville, Texas, and Matamoros, in the Mexican state of Tamaulipas, damage will be limited, due to the fact that these cities are 20-25 miles inland from the coast (Figure 2). Dolly's expected storm surge of 4-6 feet will probably not do much damage, since there are few structures near the coast in the region. Wind damage will be the primary threat from Dolly, along with flash flooding from heavy rains. Hurricane Bret spawned two damaging tornadoes in 1999, and we can expect Dolly to spawn a few tornadoes as well.

I'll have an update in the morning.
Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Quoting TheCaneWhisperer:
Just imagine if she got the eye wall closed up yesterday instead of today.


Exactly. That ULL kind of held it in check yesterday. Funny how a small little feature like that can make a HUGE difference!
2002. IMA
Quoting HouseofGryffindor:
At least this is going into an area that isn't too heavily populated.
There's the entire storm to consider, not just the eye.
2003. Walnut
Quoting centex:
Brownville should be far enough inland to miss the highest wind, but South Padre / Port Isabel should get some of the worse.


So it is no surprise that Cantore is there!
Quoting TayTay:
If she isn't classified a cat. 2 now then she will in post analysis.


She is likely to become a Cat 2 at anytime over the next 4-6 hours before landfall.
Quoting kmanislander:
Dolly is now well N of the track line to the next forecast point which is an onshore point.In fact she is almost directly across from it but still at sea.
Landfall would appear to be well North of Brownsville in the absece of a jog West now


So I am not going nuts.. thats at least two of us that see it. The HH vortex reports have it heading about 330.
I stand corrected. Thank you Storm
2008. TayTay
Landfall is within 2 hours.
No limit to how fast the ADT can rise now...T# up 0.4 in the last hour:

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 23 JUL 2008 Time : 124500 UTC
Lat : 26:00:28 N Lon : 96:49:09 W


CI# /Pressure/ Vmax
5.4 / 961.5mb/ 99.6kt



Final T# Adj T# Raw T#
(3hr avg)
5.4 6.1 6.1

Latitude bias adjustment to MSLP : -0.5mb

Estimated radius of max. wind based on IR : 12 km

Center Temp : +8.1C Cloud Region Temp : -62.6C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF
The local news here in Corpus is saying she's approaching Cat 2.
2011. MahFL
er.......no-one has mentioned the levee's much, they are in danger of being overwhelmed too.
2012. Xion
ADT numbers are going insane!

CI# /Pressure/ Vmax
5.4 / 961.5mb/ 99.6kt

I'm not making fun of Cantore - but the goggles crack me up.
2014. Hhunter
Quoting IMA:
Quoting HouseofGryffindor:
At least this is going into an area that isn't too heavily populated.
There's the entire storm to consider, not just the eye.


have you ever been there? then you don;t know a thing..
No rain west of Houston in Katy area for over an hour...
2016. expert2
extreme236 its making landfall in 30 to 60 minutes.Tv can see the ey getting close south padre island winds to near 80mph they reported.
It is wobblong North again.
Could be a 27N hit.
Quoting Orcasystems:
Quoting kmanislander:
Dolly is now well N of the track line to the next forecast point which is an onshore point.In fact she is almost directly across from it but still at sea.
Landfall would appear to be well North of Brownsville in the absece of a jog West now


So I am not going nuts.. thats at least two of us that see it. The HH vortex reports have it heading about 330.


Not nuts at all. I just looked at the radr and could not see any descernible motion to the W. If anything a slow motion of a few knots only to the NNW
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 23 JUL 2008 Time : 124500 UTC
Lat : 26:00:28 N Lon : 96:49:09 W


CI# /Pressure/ Vmax
5.4 / 961.5mb/ 99.6kt


Final T# Adj T# Raw T#
(3hr avg)
5.4 6.1 6.1



holy we crap this went from 90kt to 99.6kt
Grr, some of my posts aren't showing up now,
forget about that track I was trying to post :P

I think it will just barely make it to 105 mph
before landfall, which I predict landfall will
be sometime around 10:30am EST.
Quoting expert2:
extreme236 its making landfall in 30 to 60 minutes.Tv can see the ey getting close south padre island winds to near 80mph they reported.


Its only moving at 8 mph and its 40 miles from land...it won't make landfall in 30-60 minutes.
2022. IMA
Quoting HouseofGryffindor:
Quoting IMA:
Quoting HouseofGryffindor:
At least this is going into an area that isn't too heavily populated.
There's the entire storm to consider, not just the eye.


The hurricane force winds don't go out too far from the eye.
Right, but flooding is a major concern with this storm.
Storm Surge Cent PressureCategory Above Normal Wind (mph) (inch Hg)
One (1) 4–5 ft 74–95 Great than 28.94
Two (2) 6–8 ft 96–110 28.50–28.91
Three (3) 9–12 ft 111–130 27.91–28.47
Four (4) 13–18 ft 131–155 27.17–27.88
Five (5) 0ver 18 ft Over 155 Less than 27.17
2024. MahFL
The landfall is when the inside of the inner eye wall reaches land ? correct ?
2025. geoeye
My question, again:

Does the effect of upwelling decrease in shallow waters?
like i said last night dolly has a few
more tricks up her sleeve.this is not over by no means.expect dolly to become stationary
in the next few hours.the mexican coast is
off the hook from the strongest winds
from dolly.i said all along it would be a
texas hurricane.so hunter start eating that
crow.dolly will continue to strengthen.not looking good for middle texas coast right now.
2028. kingy
the recon plane is heading into the eye again so we will have a new pressure reading. I think we will get a cat 2 upgrade at that point too. I thought this would have hit mexican soil hours ago but for reasons I am not clear about it is still drifting with northerly jogs. If it gets past the bend in the texan coast then it has yet more warm water to run up to corpus with. This storm has surprised me with the rapid pressure drop, strong structure and willingness to stay out to sea. Not so long ago we thought this was a mexican cane. I wonder if we will see this nudge north to corpus.
StormW. Your views in particular would be great to read.
CNN has a great panel on the side of their screen...now 32miles from Brownsville and moving NW at 8 landfall in a matter of hours.
It will slow down to 5-6MPH.
And do a few Northern jumps.
2031. CJ5
Quoting MahFL:
The landfall is when the inside of the inner eye wall reaches land ? correct ?


correct
2032. zhaemom
Quoting LPStormspotter:
Quoting TampaSpin:
Everythings bigger in Texas....might be true.
Not in houston..lol!!!


Right! It sure as heck feels nice for a change, though, here in Houston!
2033. MahFL
On the radar the eye seems to be getting tighter and tighter.
HH plane is heading back in the south side for another pass, looks like. Should reach the eye in 10-15.
Quoting MahFL:
er.......no-one has mentioned the levee's much, they are in danger of being overwhelmed too.

They're talking about the levees in my part of TX. Expecting failures.
2036. TayTay
Quoting MahFL:
On the radar the eye seems to be getting tighter and tighter.


All storms do that as they approach land.
Quoting ForecasterColby:
HH plane is heading back in the south side for another pass, looks like. Should reach the eye in 10-15.


Yep...latest obs show the pressure dropping and the winds increasing so there getting close to the eye.
2038. Patrap
AT 800 AM CDT...1300Z...THE CENTER OF HURRICANE DOLLY WAS LOCATED
NEAR LATITUDE 25.9 NORTH...LONGITUDE 96.9 WEST OR ABOUT 40 MILES...
60 KM...EAST OF BROWNSVILLE TEXAS.

DOLLY IS MOVING TOWARD THE NORTHWEST NEAR 8 MPH...13 KM/HR...AND
NORTHWESTWARD TO WEST-NORTHWESTWARD MOTION WITH A SLIGHT DECREASE
IN FORWARD SPEED IS EXPECTED TODAY. ON THE FORECAST TRACK...THE
CENTER OF DOLLY WILL BE ALONG THE COAST NEAR THE TEXAS/MEXICO
BORDER AROUND MIDDAY TODAY.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 95 MPH...155
KM/HR...WITH HIGHER GUSTS. DOLLY IS A CATEGORY ONE HURRICANE ON
THE SAFFIR-SIMPSON SCALE. SOME INCREASE IN STRENGTH IS
EXPECTED...AND DOLLY COULD APPROACH CATEGORY TWO INTENSITY WHEN IT
REACHES THE COASTLINE LATER TODAY.


The Storm Heading was 340 true at 8mph.
340 is problematic as it almost parallels the Coast thru time.
Expect a prolonged event in S. Texas.
Quoting geoeye:
My question, again:

Does the effect of upwelling decrease in shallow waters?


Yes, since there is no deeper, colder water below (Felix became a Cat 5 (the second time) and made landfall at that intensity while moving over very shallow water, so shallow the TCHP maps showed virtually zero TCHP).
Eyewall just offshore.
Quoting CJ5:
Quoting MahFL:
The landfall is when the inside of the inner eye wall reaches land ? correct ?


correct


Which land though ?. The barrier islands or the shore of the mainland ?. Big difference because if it is the former those places upstream from there will face the eye coming ashore on the mainland.
Brownville radar had max winds at 122kts.
2045. centex
Lyons just said making turn, I think he was fooled by wobble. IMO it's still moving slowly NW and wobbling left and right of that.
2046. franck
Does Dolly have the dreaded pinhole eye??
Landfall is when the middle of the eye touches land.
Quoting Patrap:
AT 800 AM CDT...1300Z...THE CENTER OF HURRICANE DOLLY WAS LOCATED
NEAR LATITUDE 25.9 NORTH...LONGITUDE 96.9 WEST OR ABOUT 40 MILES...
60 KM...EAST OF BROWNSVILLE TEXAS.

DOLLY IS MOVING TOWARD THE NORTHWEST NEAR 8 MPH...13 KM/HR...AND
NORTHWESTWARD TO WEST-NORTHWESTWARD MOTION WITH A SLIGHT DECREASE
IN FORWARD SPEED IS EXPECTED TODAY. ON THE FORECAST TRACK...THE
CENTER OF DOLLY WILL BE ALONG THE COAST NEAR THE TEXAS/MEXICO
BORDER AROUND MIDDAY TODAY.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 95 MPH...155
KM/HR...WITH HIGHER GUSTS. DOLLY IS A CATEGORY ONE HURRICANE ON
THE SAFFIR-SIMPSON SCALE. SOME INCREASE IN STRENGTH IS
EXPECTED...AND DOLLY COULD APPROACH CATEGORY TWO INTENSITY WHEN IT
REACHES THE COASTLINE LATER TODAY.


The Storm Heading was 340 true at 8mph.
340 is problematic as it almost parallels the Coast thru time.
Expect a prolonged event in S. Texas.


Exactly the point I made earleir when I said 27N was not out of the realm of possibility for landfall ( that is the core to come ashore on the mainland )
2049. kingy
2025. The deeper the ocean, the more the potential for deep cold water to be welled upwards to the surface. However shallow water doesn't have the deep cold water to upwell, rather the existing water is churned over and over. So a slow moving storm over warmer coastal waters will not weaken anything like as quickly as a stationary storm over deep sea. Of course you have to consider land interactions with coastal storms, these will weaken canes and limit moisture uptake. Here that hasn't affected Dolly too much.
CI# /Pressure/ Vmax
5.4 / 961.5mb/ 99.6kt


Final T# Adj T# Raw T#
(3hr avg)
5.4 6.1 6.1
Dolly just jumped NOrth again...

Dolly keeps following the coast.
Middle Texas is not out of the woods.
40 miles from Brownsville, that is less than 2hrs to landfall,as Brownsville is a good 20 miles inland.
2054. Michfan
Her eye is too big to be pinhole. Ever since Wilma everyone thinks there is a pinhole. Who has those pics that show the differences?
2055. Drakoen
I see Dolly has strengthened significantly. Looks very impressive now with a small eye.
2056. geoeye
2039.

Thank you for answering my question.
Quoting TampaSpin:
Dolly just jumped NOrth again...



I expected a NE jump but i have no coordinates to verify that.
2058. Hhunter
any one want to bet that cantorie gets driven off that dune by wind and water rise...anyone catch them say the 3-5 ft water rise had not come yet and he was close enough to bridge that gap...funny stuff..
2059. CJ5
Quoting franck:
Does Dolly have the dreaded pinhole eye??


It larger than a pinhole eye..20nm
Dolly has consistently suprised us - what next!
2061. MahFL
The Brownsville Library rapidfire link went dead, either they lost power or the internet is down.
Tampa Spin, yep, i see that. Port Isabel may dodge the eye.
2063. centex
When we going to have another center pass and vortex message?
2064. Xion
961 mb!

Not a Cat 2? Come on...I doubt it.
000
URNT15 KNHC 231321
AF302 1904A DOLLY HDOB 28 20080723
131030 2528N 09645W 6969 03033 9942 +074 +074 265055 057 058 017 00
131100 2530N 09645W 6964 03036 9925 +083 +083 260054 054 060 011 00
131130 2532N 09645W 6965 03022 9915 +081 +081 262057 059 062 011 00
131200 2534N 09645W 6968 03010 9887 +094 +090 265059 060 064 009 00
131230 2535N 09646W 6963 03005 9868 +098 +090 266061 062 064 009 00
131300 2537N 09646W 6969 02986 9857 +096 +090 267063 065 067 012 00
131330 2539N 09646W 6965 02975 9859 +084 +084 267067 070 069 012 00
131400 2540N 09646W 6967 02958 9828 +094 +090 268069 071 069 008 00
131430 2542N 09646W 6969 02935 9797 +100 +090 266069 069 070 011 00
131500 2544N 09646W 6961 02926 9787 +092 +090 264069 071 068 013 00
131530 2546N 09646W 6968 02895 9756 +095 +090 265066 068 061 008 00
131600 2547N 09646W 6964 02874 9704 +117 +090 264054 061 059 003 00
131630 2549N 09646W 6968 02845 9651 +140 +090 260037 041 059 005 00
131700 2551N 09646W 6969 02824 9610 +164 +090 245021 027 048 002 03
131730 2553N 09646W 6969 02821 9610 +160 +090 222006 009 016 004 03
131800 2554N 09648W 6965 02821 9610 +155 +090 033002 005 001 002 00
131830 2556N 09649W 6963 02833 9627 +148 +090 059007 009 000 004 03
131900 2557N 09649W 6971 02828 9654 +139 +086 084012 014 001 003 00
131930 2559N 09649W 6964 02830 9628 +146 +090 091015 016 000 004 00
132000 2601N 09649W 6966 02821 9622 +144 +090 090025 028 022 003 00
$$

961mb.
storm w i think you better go look at
your data again.they been talking about this
high pressure all night long.the high is not strong enough to bother dolly.dolly will keep moving n/nnw and start to paralell the
coast of texas.dolly will be big trouble.
the trough is getting stronger and dolly has the
weakness all the way up to the upper
texas coast.by that time dolly should be pretty close to a cat 3.
The google hurricane hunters tracking just showed a 964mb on the last pass.
In Corpus Christi here. Nothing but rain so far. At my house we have gotten about 1.25" so far and are about to get hit by a pretty strong band. There was just a report of a water spout east of Port Aransas comming this way. I hope the winds don't pick up too much.

Wish us luck.
2069. kingy
964mb just came in from the recon
2070. hulakai
2048. kmanislander

not a very good scenario. will stay over water longer and get stronger? at 8mph or less someplace is going to take a nasty beating for 3-4 hours.

could just be a jog caused by interaction with land. let's hope so.
2071. geoeye
Thanks to you, Kingy, as well for answering my question.

My understanding of upwelling had more to do with thermohaline circulation in the NE Atlantic than the tropics, but I suppose the same physical principles apply, especially close to land.
Greetings all. Long-time lurker.

I have a place on the bay in P.I. and live 50 miles inland. I'll post for as long as my hughesnet holds up.

One thing many may not know is that we just had a 5 day / 9+ inch rain event about 10 days ago on both sides of the river. All the area lakes in Mexico are 90-100% capacity and the flooding event may not even reach its peak until after the weekend.
**TORNADO WARNING*** TORNADO 14 MI SW OF CORPUS CHRISTI...
new tornado near Ingleside reportedly will be moving right through Downtown CC by 10:10am...