INVEST 91L -Discussions,Analysis and Imagery

[Extremeweatherguy]

18Z NAM (which is a terrible tropical model) has system near Corpus.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_054l.gif

yeah, it is terrible, but in this case it is generally in line with the other models. Very similar to the GFDL.

[vaffie]

18Z NAM (which is a terrible tropical model) has system near Corpus.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_054l.gif

You must admit though, that for all of our gripes about the NAM and Canadian models, they were the only ones that predicted five days ago that a low would form near Cancun today and trek in the direction it's currently doing. All the other models kept it as a weak tropical wave going due west into Mexico. You got to give them credit when they get it right.

[PTrackerLA]

Well this has become quite interesting throughout the day. Hopefully this stays a weak TS for those in Texas but the rain will be appreciated after this heat wave.

[jasons2k]

These are comments from Jeff Lindner on this system:

Potential for tropical cyclone to impact the TX coast.

Changes to forecast from Wednesday through Friday are required based on latest HPC and NHC thinking and 12Z model guidance. At 300pm visible images along with radar from Cancun, Mexico clearly show a well defined low level circulation about 100 miles N of the Yucatan coast. Upper level low over the central Gulf of Mexico is moving W toward the S TX coast with strong southerly shear across the top of 91L. Shear should weaken over the next 12 -24 hours as the upper low moves westward. Steering of 91L then comes under the influence of large scale high over the southern plains.

Current model guidance including 12Z run of GFDL takes the system into the S TX coast between Brownsville and Corpus Christi which is also supported by the GFS and NAM. Will disregard 68kts by the SHIPS and follow closer with the 50kts depicted on the DSIPS guidance suggesting a landfalling tropical storm late Wednesday along the lower TX coast.

Will need to make significant changes to wind and seas forecast and rainfall/QPF forecast starting Wednesday. At this time core of adverse weather should impact areas from Matagorda Bay southward.

Seas: Expect coastal winds to shift to the ENE Tuesday and begin to increase by Wednesday as Gulf pressures lower. Wave Watch III guidance builds offshore swells into the 8-12 foot range starting early Wednesday as tropical storm force winds spread into the outer coastal waters. Will increase from flat seas of 1-2 feet into 6-8 feet coast to 12 feet offshore. Increasing swells and winds will result in tidal run-up along the beaches starting late Tuesday. Will increase tides into the 1.0-2.0 foot above normal range (Brazoria County N) and into the 2.0-2.5 foot range (Brazoria County S). Could see tides up to 4.0 feet above normal around Matagorda Bay by late Wednesday with overwash of protection dunes.

Winds: Will increase winds into the 20-30mph range out of the E to ENE for Wednesday. May be close to northern extent of TS force wind radii over the Matagorda Bay area late Wednesday. Squalls and rainbands will likely produce gust at or above 40mph along the coast.

Rain Chances: Will up chances to 50% by Wednesday and may need to go even higher especially W of I-45 based on forecast track of center and deep surge of 2.50+ PWS. NAM and GFS show most of the heavy rains N and E of the center of the system…so even a landfall in S TX would support heavy rains and squalls northward up the TX coast. HPC progs show 6.4 inch bullseye near the landfall locations with widespread 2-4 inches contours up the TX coast into Matagorda Bay.

Residents along the TX coast should closely monitor the progress of this system.

Continued significant forecast changes are possible based on the forecast track and intensity of the system.

[Scorpion]

If this system moves slowly enough I would not be surprised if a Cat 1 came out of this

[Extremeweatherguy]

The NAM is interesting. After landfall near Corpus it turns the system more northward into central TX. If this happens, then we could be looking at lots of rainfall here in SE Texas.

[Aric Dunn]

pressure 1009 In Cancun.

http://weather.noaa.gov/weather/current/MMUN.html winds are pretty light

but im not surprised since its on the south side of the circ

[Aric Dunn]

cancun radar


can anyone make a loop out of the images and post it please

LLC just NW was radar site not more than 80 miles NW just off shore

[Aric Dunn]

119
ABNT20 KNHC 132106
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 PM EDT MON AUG 13 2007

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER ISSUING ADVISORIES ON TROPICAL
DEPRESSION FOUR...LOCATED ABOUT 1900 MILES EAST OF THE LESSER
ANTILLES.

DISORGANIZED SHOWER ACTIVITY CONTINUES IN ASSOCIATION WITH A WEAK
AREA OF LOW PRESSURE THAT IS CENTERED JUST NORTH OF THE
NORTHEASTERN TIP OF THE YUCATAN PENINSULA. UPPER-LEVEL WINDS ARE
GRADUALLY BECOMING MORE FAVORABLE FOR DEVELOPMENT OF THIS
SYSTEM...AND A TROPICAL DEPRESSION COULD FORM TONIGHT OR TOMORROW
AS THE LOW MOVES TO THE WEST-NORTHWEST AT 10 TO 15 MPH. INTERESTS
IN THE WESTERN GULF OF MEXICO SHOULD MONITOR THE PROGRESS OF THIS
SYSTEM. AN AIR FORCE RESERVE RECONNASSIANCE PLANE IS SCHEDULED TO
INVESTIGATE THIS SYSTEM TOMORROW AFTERNOON...IF NECESSARY.

[RL3AO]

Code Orange

[Aric Dunn]

it appears the LLC has slowed considerably .. than earlier but it should begin to move again ... but in the mean time the upper low is pulling away which is not good beacuse it should put the system in a very favorable upper level environment... with a decent outflow jet setting up later tonight and tomorrow .. but lets see if the convection can become a little less disorganized

[vaffie]

it appears the LLC has slowed considerably ..

Any significant slowing will ultimately result in a more northerly track, since it is on Wednesday that the SE ridge begins to move eastward creating a weakness in the central plains. It is Wednesday midday that this storm is predicted by the models to reach the Texas coast, so if landfall is delayed by a 12-24 hours as a result of slower movement, landfall will be further up the coast. Slowing down will give more time to create a stronger storm that will more likely move more northerly as a result too. People in the Upper Texas coast should not write this off yet.

[clevelandindians]

Channel 2 KPRC in houston has a 50 percent chance of rain wednesday

[Stormcenter]

If you stepback and look at the whole mass of weather entering the GOM you can see how
things are slowing but surely coming together. I would not be surprised
to see a new low pressure center form. IMO

http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html

[Stratosphere747]

I noticed a bit earlier the ULL had begun to move away a bit faster from a possible low near Cancun, when it had seemed to tug it along this morning. Lets see how it evolves over the next 6hrs or so.

[KFDM Meteorologist]

This will bring moisture to the area Wed/Thur. This system could become a TS or CAT 1 by Landfall Thursday.

[clevelandindians]

If you stepback and look at the whole mass of weather entering the GOM you can see how
things are slowing but surely coming together. I would not be surprised
to see a new low pressure center form. IMO

http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html

do you think we will see a TD tonight

[KFDM Meteorologist]

Possibily. It will get going again tonight.

[Stormcenter]

If you stepback and look at the whole mass of weather entering the GOM you can see how
things are slowing but surely coming together. I would not be surprised
to see a new low pressure center form. IMO

http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html

do you think we will see a TD tonight

I personally don't think so.

[Tampa Bay Hurricane]

Appears that there will be development:
shear is low and oceanic heat content is high...
A tropical storm is possible out of this.
In fact a category 1 hurricane is possible.
Texas should watch it closely,
as the wunderground.com tropical
models show it going there:
http://www.wunderground.com/tropical/tr ... model.html
In fact the models are on tight agreement for South Texas.