September 2014: Seasonably Warm & Dry To End The Month

[ticka1]

What track is it showing? GFS on 97L?

[srainhoutx]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT FRI AUG 29 2014

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center has issued the last advisory on
Cristobal, which has become a post-tropical cyclone a few hundred
miles east of Cape Race, Newfoundland.

1. A large area of disorganized cloudiness and thunderstorms over
the central Caribbean Sea is associated with a tropical wave.
Upper-level winds are forecast to become a little more favorable
for development on Saturday while the wave moves over the
northwestern Caribbean Sea. The disturbance is forecast to move
across the Yucatan peninsula on Sunday and into the southwestern
Gulf of Mexico by Monday, where environmental conditions are
expected to be conducive for some gradual development.
* Formation chance through 48 hours...low...near 10 percent.
* Formation chance through 5 days...medium...30 percent.

Forecaster Brown

[srainhoutx]

The 12Z GEFS ensemble members appear to have most of the individual members clustered near Tampico. As always, until a defined center forms and we have an actual storm to track, nothing is set in stone.

[Katdaddy]

Historic. Be thankful this was not reality for the Houston-Galveston areas. Are you ready? I will never forget reading this public weather statement.

URGENT – WEATHER MESSAGE
NATIONAL WEATHER SERVICE NEW ORLEANS LA 413 PM CDT SUN AUG 28 2005

…EXTREMELY DANGEROUS HURRICANE KATRINA CONTINUES TO APPROACH THE MISSISSIPPI RIVER DELTA…

…DEVASTATING DAMAGE EXPECTED…

MOST OF THE AREA WILL BE UNINHABITABLE FOR WEEKS…PERHAPS LONGER. AT LEAST ONE HALF OF WELL CONSTRUCTED HOMES WILL HAVE ROOF AND WALL FAILURE. ALL GABLED ROOFS WILL FAIL…LEAVING THOSE HOMES SEVERELY DAMAGED OR DESTROYED.

THE MAJORITY OF INDUSTRIAL BUILDINGS WILL BECOME NON FUNCTIONAL. PARTIAL TO COMPLETE WALL AND ROOF FAILURE IS EXPECTED. ALL WOOD FRAMED LOW RISING APARTMENT BUILDINGS WILL BE DESTROYED. CONCRETE BLOCK LOW RISE APARTMENTS WILL SUSTAIN MAJOR DAMAGE…INCLUDING SOME
WALL AND ROOF FAILURE.

HIGH RISE OFFICE AND APARTMENT BUILDINGS WILL SWAY DANGEROUSLY…A FEW TO THE POINT OF TOTAL COLLAPSE. ALL WINDOWS WILL BLOW OUT.

AIRBORNE DEBRIS WILL BE WIDESPREAD…AND MAY INCLUDE HEAVY ITEMS SUCH AS HOUSEHOLD APPLIANCES AND EVEN LIGHT VEHICLES. SPORT UTILITY VEHICLES AND LIGHT TRUCKS WILL BE MOVED. THE BLOWN DEBRIS WILL CREATE ADDITIONAL DESTRUCTION. PERSONS…PETS…AND LIVESTOCK EXPOSED TO THE WINDS WILL FACE CERTAIN DEATH IF STRUCK.

POWER OUTAGES WILL LAST FOR WEEKS…AS MOST POWER POLES WILL BE DOWN AND TRANSFORMERS DESTROYED. WATER SHORTAGES WILL MAKE HUMAN SUFFERING INCREDIBLE BY MODERN STANDARDS.

THE VAST MAJORITY OF NATIVE TREES WILL BE SNAPPED OR UPROOTED. ONLY THE HEARTIEST WILL REMAIN STANDING…BUT BE TOTALLY DEFOLIATED. FEW CROPS WILL REMAIN. LIVESTOCK LEFT EXPOSED TO THE WINDS WILL BE KILLED.

AN INLAND HURRICANE WIND WATCH IS ISSUED WHEN SUSTAINED WINDS NEAR HURRICANE FORCE…OR FREQUENT GUSTS AT OR ABOVE HURRICANE FORCE…ARE POSSIBLE WITHIN THE NEXT 24 TO 36 HOURS.

[ticka1]

just watched a 54 min youtube video jim edds posted that i have not seen before - the storm surge was horrible

[srainhoutx]

Update from Jeff regarding our new Invest 99L S of Jamaica/The Cayman Islands:

Tropical wave over the west-central Caribbean Sea south of Jamaica has been classified as invest 99L.

 

Deep convection has developed this afternoon in conjunction with the westward moving tropical wave and surface pressures are slowly starting to fall. While there does not appear to be any closed surface circulation at this time upper level winds will become increasingly favorable for develop as the system moves into the NW Caribbean Sea Saturday and Sunday.

 

General steering flow over the northern Gulf of Mexico is currently toward the NW and NNW, but should gradually back toward the WNW and W over the next 5 days as high pressure attempt to re-establish behind the departing trough currently over the central plains into NC TX. This should result in a general WNW to NW motion of any developing tropical cyclone in the NW Caribbean Sea or southern Gulf of Mexico and this is supported by much of the global model guidance. The system should emerge into the southern Gulf of Mexico late Sunday or early Monday.  

 

Forecast models are not overly aggressive with this system which seems a bit odd given the generally favorable conditions. Land interaction with the Yucatan peninsula could be one reason, although developing tropical cyclones tend to hold together fairly well while crossing this generally flat landmass. First run of the tropical models and SHIPS intensity guidance does bring the system to a 85kt hurricane in the southern Gulf of Mexico which is somewhat in line with what the 00Z CMC was showing (977mb hurricane). All other model guidance keeps the system general an open wave or a weak tropical storm including the GFS.

 

Note:

Radar images from both Houston and Lake Charles this evening show a well defined circulation approaching the Chambers/Jefferson County coastline. Surface observations have not shown any significant pressure falls with this feature. Rollover Pass just gusted to 24kts out of the east and Texas Point at the Louisiana border is gusting to 24kts and 27kts within the last 2 hours. Marine obs at the buoy 20 E of Galveston, Rollover Pass, and High Island suggest nothing out of the ordinary besides gusty E to ESE winds. The well defined radar circulation is likely based in the 1000-3000 ft level since there are no defined NW winds over Galveston Island or points west to near Freeport as suggested by the SE moving radar echoes.

 

Think best chances of excessive rainfall overnight will be from Freeport to Liberty and SE in association with the landfall of this feature. Low level speed convergence is already establishing over the Gulf waters from 60-100 miles offshore and expect to see a rapid increase in deep convection in the next few hours. Radar estimates today and observations show rainfall amounts of up to 4.34 inches over Sugar Land so this air mass is very much capable of some impressive short term rainfall amounts under the stronger cells.

 

[srainhoutx]

A broad area of lower pressures and disorganized disturbed weather the NW Caribbean continues to slowly move WNW to NW this morning. The NHC has increased development chances slightly to 40% early next week when conditions may become more favorable for tropical development once it passes over the Yucatan Peninsula on Sunday into Monday and enters the Bay of Campeche. The overnight ensembles are still rather well clustered near or just N of Tampico Tuesday into Wednesday.

[Cromagnum]

No sense in worrying about this one. You guys couldn't even get rain pegged all week and are stoill dropping the ball on that. Why should anyone put any stake in forecasts for a storm a week out when everyone is running in failure mode?

[srainhoutx]

The ensembles are rather insistent on pressures continuing to fall across the SW Caribbean Sea into the Western Gulf in the medium range and beyond. In fact the pressure tendency (1008mb or less) in the Western Caribbean and Western Gulf is lower during the first 10 days or so than we have seen all season anywhere in the Atlantic Basin.

[Katdaddy]

Its not about worrying. Its about awareness and having a plan should a tropical threat materialize for the Upper TX Coast and SE TX over the next month. It only takes one.

[Kludge]

My (non expert) opinion is that this will become Dolly in the BOC, minimal hurricane at most. The only affect on SE TX will be to suck any available moisture away from the sea breeze that would normally develop.

I don't mean to be a pessimist here... but I've just seen this movie too many times before.

If anyone can give me hope that the above won't happen, I would love to hear about it.

What was once a very mild and enjoyable Summer has become a depressing broiler. I need cheering-up.

[jasons2k]

I think you're right - and I am still dry as a bone here. Nothing all week long.

[cperk]

No sense in worrying about this one. You guys couldn't even get rain pegged all week and are stoill dropping the ball on that. Why should anyone put any stake in forecasts for a storm a week out when everyone is running in failure mode?

When you say you guys i hope you're not talking about anyone on this forum,because to my knowledge no one issues forecast here.We just discuss the weather.

[ticka1]

Okay I have to ask this question - on the long range forecast are there any strong cold fronts pushing down here to texas?

[Ptarmigan]

My (non expert) opinion is that this will become Dolly in the BOC, minimal hurricane at most. The only affect on SE TX will be to suck any available moisture away from the sea breeze that would normally develop.

I don't mean to be a pessimist here... but I've just seen this movie too many times before.

If anyone can give me hope that the above won't happen, I would love to hear about it.

What was once a very mild and enjoyable Summer has become a depressing broiler. I need cheering-up.

When a hurricane hits south of Texas in Mexico, they tend to bring more moisture. The larger they are, the more moisture they bring. Think Alex in 2010.

[djjordan]

It would be beneficial to Texas if future Dolly were to hit in Mexico. Remember the "dirty side" is the right side which in this case would drag all kinds of moisture northward with it. Now, it does depend how close it gets to Texas so it bears watching for sure.
Other than that, looks like moisture is gonna stick around and continue rain chances for much of this week coming up. Sunday should actually be wetter than today was.

[Andrew]

Models continue to show little threat locally (SE Texas) from 99L as it crosses the Yucatan into the BOC. Mid level heights will slowly build as ridging takes over much of the gulf coast. Generally, high pressure will be centered over western parts of Texas/Mexico , extending East into parts of Alabama and Mississippi. With slow development expected for 99L, low level steering will push the system into parts of Mexico (maybe up to the border if development is accelerated). Don't expect much in the way of moisture from 99l as any development will only help to localize storms closer to the center, and if development doesn't happen the system will move even farther south into Mexico. Luckily rain chances don't totally go away as a weakness from high pressure remains over the area. The sea breeze should remain active into the beginning of the month with isolated showers possible. Global models are the most bullish with rain chances, but expect the sea breeze to become less active as we head further into the week and high pressure builds in further. From a synoptic scale, a zonal pattern will remain for much of the country with little activity (for next week) in the tropics.

NAM 500mb chart for Tuesday Morning. Take note of the clockwise motion (high pressure) over Arizona/New Mexico/Mexico border and Alabama/Mississippi border.

namconus_z500_vort_us_20.png

GFS 500mb for Tuesday Morning.

gfs_z500_vort_us_10.png

[srainhoutx]

While model support is lackluster, past experience suggests that as these weak tropical disturbances passing over the Yucatan Peninsula can do some strange things development wise and even slowly strengthen. If the disturbance meanders a couple of days in the Western Gulf, there is some potential of development taking into account the Isthmus of Tehuantepec wind gap and lower pressures across the Western Gulf with a weak trough along the NE Mexico/South Texas area this morning.

[Katdaddy]

A similar environment is in place that brought 7.87" rain to Lake Charles, LA yesterday off to our E. This morning heavy rains are developing along the Middle and Upper TX Coast. Some areas may pick up 2-4" with the potential for even higher amounts.

[srainhoutx]

Update from Jeff regarding 99L:

Strong tropical wave and associated deep convection is moving into the western Caribbean Sea this morning.

Satellite images and surface observations show an ill defined wave axis with moderate to at times heavy convection near and to the east of this feature. The wave is moving WNW and will landfall on the eastern Yucatan peninsula later today with little development likely.

99L will emerge into the southern Gulf of Mexico Monday and continue on a WNW to NW movement. Conditions in the southern Gulf of Mexico will be fairly favorable for development with weak upper level winds shear and very warm waters. While model support for development is not overly strong, the southern Gulf of Mexico is notorious for producing fairly quick developing tropical systems in part due to the favorable concave shape of the coastline which helps to increase counter clockwise circulations.

Building high pressure along the US Gulf coast should result in a general WNW to NW track toward the eastern Mexican coastline around midday week.

Some moisture will push northward toward the TX coast both Tuesday and Wednesday, but how much depends how much development takes place prior to landfall. The more the system develops and contracts the less moisture that will pull northward.

Additionally, with low pressure to the south an ESE fetch will develop over much of the Gulf of Mexico which may help to build seas and wave action over the western Gulf of Mexico mid week. Could see some minor tidal response to the building wave action by late Tuesday.