ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[KWT]

Yea short term it will have to deal with this shear. But the upper level environment past today looks too good for this not to deepen substantially IMO. Itll have multiple outflow channels.

The other interesting thing is I think this may well mean the system will end up being a Texas landfall, the fact the ULL isn't really moving and inducing shear when it wasn't expected too suggests the weakness maybe stronger then expected by some models and may take it a little more to the north than expected before the bend back, but then again the motion maybe slower in return and that was balance it out.

Almost back up to its pressure last night after seafall...does seem to be slowly weakening right now thanks to that shear, its a problem there can be no doubt but I do think only a short term issue.

[HouTXmetro]

What can we take from the fact the it appears the Alex is starting to appear elongated from SW to NE?

[timNms]

What can we take from the fact the it appears the Alex is starting to appear elongated from SW to NE?

It has been my observation that storms tend to move in the direction in which they are elongated. FWIW, I'm no expert.

[ConvergenceZone]

They may bring the forecasted winds down on the next advisory. It will be interesting what they say. It doesn't look healthy now that's for sure.

[x-y-no]

What can we take from the fact the it appears the Alex is starting to appear elongated from SW to NE?

It's not really that Alex is elongated, it's that convection is being suppressed on the SE by land and on the NW by shear.

[timNms]

Looks like Alex is quite fond of Mexico. Seems to be moving along the coastline.

[Air Force Met]

What can we take from the fact the it appears the Alex is starting to appear elongated from SW to NE?

It's not really that Alex is elongated, it's that convection is being suppressed on the SE by land and on the NW by shear.

Exactly. The NW shear is the thing really making him look worse than he is. Once he moves just a little more to the north (50 miles or so...he should be feeling a lot better.

[Comanche]

Looks like Alex is quite fond of Mexico. Seems to be moving along the coastline.

Montezumas revenge? Can't get to far away from the bathrooms.

[Blown Away]

IMO the next 24 hours will tell us how far north Alex goes before landfall. If Alex deepens/gets stronger soon the trough will draw Alex further north and then maybe a Texas landfall and if he stays a mess like he is now the trough won't pull Alex far enough north and he will landfall in Mexico. One thing that is pretty certain the ridge will build in a few days and push Alex inland. My 2 cents.

[funster]

The water temperatures are warmer as well once Alex stops hugging the coast. This could be limiting his development. I had a good SST map earlier that showed this but i lost it

[Brent]

Yeah I'm pretty sure its decoupled somewhat again, that shear is going to have to lift out if its going to strengthen much beyond where it is now...thats probably why the pressure has risen again.

I'd have thought the shear will eventually ease off but the fact Alex is caught in a more northerly airflow is probably why its being sheared, once it edges more westwards I think shear will ease off a little further as the upper high starts to send it back westwards, which would probably induce a more condusive set-up aloft...

KWT, I"m really starting to think that this is why all the dynamic models
are keeping this a tropical storm or less. We need to be prepared obviously,
but maybe we will get lucky and only have a tropical storm on our hands as it makes
landfall...I'm getting more and more swayed in that direction.

That's a very dangerous assumption IMO. The conditions get more favorable once it gets just a little more north.

I continue to be baffled why the models don't strengthen it much, and don't buy it, but as we know, intensity forecasts are usually very bad.

[brunota2003]

AF Met, what is your current thinking on this system as far as track goes? I probably missed your post on it somewhere, so

[hurricaneCW]

Alex looks very bad right now, clearly some shear going on and a bit of dry air intrusion. This is more typical of a June system. Maybe we'll get lucky and Alex doesn't strengthen much but there is tremendous uncertainty with Alex right now.

[SunnyThoughts]

What can we take from the fact the it appears the Alex is starting to appear elongated from SW to NE?

It's not really that Alex is elongated, it's that convection is being suppressed on the SE by land and on the NW by shear.

Exactly. The NW shear is the thing really making him look worse than he is. Once he moves just a little more to the north (50 miles or so...he should be feeling a lot better.

How long before he starts moving though.... Is it possible he just sits there for a day or two undergoing this NW shear before he even starts to move?

[ROCK]

start to see the LLC on 1KM vis loop...moving NNW or N right now...

http://www.ghcc.msfc.nasa.gov/GOES/goeseastconus.html

[mulley]

yes, just confirmed Dr. Frank will be in the house
for the 5pm and 6pm newscast on KHOU Ch.11 tonight w/ Gene Norman.

[KWT]

Exactly. The NW shear is the thing really making him look worse than he is. Once he moves just a little more to the north (50 miles or so...he should be feeling a lot better.

I think rather than north it needs to get more west before it feels better conditions IMO...then again I'm not sure about the conditions becoming more condusive so quickly, the upper low will move out with time but sheared systems tend to rarely only get sheared for 6hrs, it tends to last longer then that I find...I'd dare say the high reoslution models may not be nearly quite so keen on reducing shear as the SHIPS suggest...

That being said I think its only so long before it eases to the NE, but I'm thinking may take a little longer then the next few hours for that to occur...still *ample* time for a hurricane!

Ps, it is moving BUT the shear is making it seem like its not, the LLC may well be exposed soon at this rate...however I don't think much if any weakening will occur, I've seen plenty of these sorts of systems at 45-55kts before.

[jasons2k]

Latest from Jeff Lindner:

At 1000am a Hurricane Watch is issued from Baffin Bay, TX to La Cruz, MX

A Tropical storm watch will likely be issued later today or early Tuesday for portions of the middle TX coast.

Preparations for the landfall of a large hurricane along the lower TX coast should begin.

Discussion:

Little change in the overall track guidance from this morning although the NHC did adjusted slightly northward at the 1000am advisory with a landfall now aimed just south of Brownsville. Will focus this e-mail on the impacts with the understanding that the track error remains large and potential for adjustments northward are possible resulting in significant changes on the impacts. Recon did report in with 66kt flight levels winds a few hours ago and a short term motion of NNW.

Impacts:

Subject to significant changes based on any track changes

Storm Surge:

Large size of Alex is forecast to result in a large storm surge along the lower TX coast. Current forecast indicate a storm surge of 6-8 feet along South Padre Island and up to as high as 12 feet at Port Isabel. Water level rises will impact the entire TX coast with tides forecast to run 3-4 feet above normal by Wednesday AM along the upper TX coast which may causes issues on the west end of Galveston and Bolivar. 4 foot warning level may be exceeded and a coastal flood watch/warning will likely be issued later today/early Tuesday. From Matagorda Bay south, tides may run slightly higher than 4.0 feet especially from Port O Connor southward and at the heads of any east/west aligned bays.

Rainfall:

Massive tropical plume heading for the TX coast is already spreading inland with numerous showers. Rainfall will continue to increase as moisture spreads toward the coast in Alex’s large circulation field. HPC guidance brings excessive core rainfall into S TX of 10-15 inches with lesser amounts up the TX coast, but still possibly significant. This looks to be a very wet system over a large area. For now will hit the upper TX coast area with a widespread 2-4 inches with isolated amounts up to 6 inches. Matagorda Bay southward can add an additional 2-3 inches on those totals. Excessive rainfall will likely begin on Wednesday PM.

Winds:

Hurricane force winds are possible from Baffin Bay southward into Mexico where the hurricane watch is in effect. Large circulation could bring TS force winds as far northward as Rockport and possibly even Port O Connor. Sustained damaging winds of 80+mph will be confined to extreme S TX over the SPI and Brownsville areas. There is potential for sustained category 2 conditions over S TX (winds sustained above 95mph).

Tornadoes:

Much of the TX coast will lie within the favored NE side of the circulation supportive of tornado genesis in land falling tropical cyclones. Feeder bands are very good tornado producers and they can produce tornadoes well away from the landfall point

Actions:

State of Texas is activating state wide resources to respond to this threat.

Shelter teams are being deployed to the RGV to support any evacuation orders with San Antonio and Austin readying for any general population evacuations that may be called.

Residents along the TX coast….especially south of Corpus Christi should enact their hurricane preparation plans at this time and be prepared to evacuate if ordered to do so.

Remember a hurricane is not a point and while the worst conditions will be near and surrounding landfall, adverse impacts will be felt hundreds of miles away from the point of landfall.

Also remember that the track error is potentially 150-200 miles at this time period and do not focus on the exact track but the overall error cone. The same preparations should be ongoing in Port O Connor as on South Padre Island.

[Air Force Met]

AF Met, what is your current thinking on this system as far as track goes? I probably missed your post on it somewhere, so

I am still (and have been since Friday) calling for a near the border hit...50 miles either side. I concede that it is a good thing Alex is taking his own sweet time in the southern Gulf and this is why the GFS has switched to the west...not for any other reason. If Alex were moving at 10 kts...he would likely follow the GFS tracks from yesterday because he would outrun the ridge.

I did a micro analysis of the heights at 500 mb from 12z... and the path is open for him to move NNW towards the upper TX coast. THat is where the break currently is. IF he begins to move with any purpose over the next 6 hours...the forecast models will shift north. If he meanders down there...they will shift south of BRO again.

[Frank2]

I haven't checked the VIS for the past 3 hours and was surprised to see that Alex appears to have weakened a little (perhaps due to dry air, per the TCD):

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

P.S. Oops - shear not dry air...