August - Warm and Dry Weather Returns To End The Month

[srainhoutx]

A final good morning from the Lower Keys. There has been a lot of chatter about a potential tropical disturbance developing in the NW Caribbean Sea/SW Gulf of Mexico later in the week, but indications continue to suggest very mixed signals via the reliable operational and ensemble guidance. What we do know as of this morning.

1. A rather strong eastern trough with a close 500mb (upper low) appears to develop over the Great Lakes and an unseasonable polar air mass sags S to at least the Tennessee Valley/Mid Atlantic by the weekend. This frontal boundary may attempt to drop S as a trough approaches the Northern Gulf Coast. The upper ridge that has plagued Texas will move further W into the Desert SW as several upper air disturbances ride S to SE along the Western flank of the Eastern Trough.

2. An area of unsettled tropical weather currently located across the Central Caribbean as well as energy emerging off the N W Coast of Venezuela will slowly organize and drift NW toward the Yucatan near Belize and Cozumel. At this time it does appear that conditions will become somewhat favorable for development as wind shear relaxes and the tropical disturbance gains some convection before moving across the Yucatan into the SW Gulf of Mexico/Bay of Campeche.

3. There are some indications that the eastern trough may be a bit transient or not lasting too long and the frontal boundary that sags S near the Northern Gulf coast will retreat N as Atlantic high pressure re asserts across Florida. Two camps are developing via the reliable computer models to what may happen with the Gulf tropical disturbance. The Euro ensemble mean suggest a weak system that continues WNW to NW and will eventually head inland along the NE Mexico Gulf Coast/S Texas. The NAEFS tends to agree with this scenario, although the NAEFS suggest two areas of vortisity may develop with one heading inland in S Texas and the other along the Louisiana Gulf Coast. The Operational GFS/Canadian computer models suggest a highly sheared system being picked up by the trough and moving what ever attempts to develop NE toward the Florida Panhandle.

Needless to say this is a very complex and complicated pattern and a lot will depend on how deep the eastern trough drops S and how strong the tropical disturbance actually becomes, if it even develops. Expect a lot of daily changes with the forecasts with all the volatility. Interests from Vera Cruz, Mexico to Tampa, Florida should monitor the forecasts for the next several days.

[srainhoutx]

Morning e-mail from Jeff:

Wetter weather over the weekend will gradually be replaced with warming temperatures and drier conditions for the next few days.

Air mass remains fairly moist this morning with PWS in the 1.8-2.0 inch range with a few showers noted on the radar across the coastal areas and even inland areas. Air mass will slowly dry today and suspect that shower and thunderstorm development will be delayed until around noon or the early afternoon instead of the mid to late morning as seen over the weekend. Storms will again feature gusty winds and localized very heavy rainfall, but overall coverage will be near 30-40%.

High pressure builds over the region Tuesday and Wednesday and this should end any rain chances and allow afternoon highs to push back into the upper 90’s or low 100’s. Eastern US troughing begins to amplify toward the end of the week and the ridge of high pressure over TX and LA is forced westward into the SW US which allows downstream NNW to N flow aloft over much of the state. A weak cool front in the northerly flow looks to approach the area as early as late Wednesday afternoon and slowly cross the area on Thursday. With the ridge aloft off to the west and subsidence weakening along with pooling moisture along the boundary decent rain chances will be returned from late Wednesday through late Thursday. Some of this activity may be well organized with more widespread wetting rainfall compared to the scattered nature of the activity lately. Front looks to actually make the coast and limp offshore on Friday with surface dewpoints falling into the mid to upper 60’s…a treat for mid August. Front will have little to no impact on afternoon high temperatures, but morning lows will run a few degrees cooler (lower 70’s) and with the drier air in place it will feel more pleasant.

Tropics:

With the plethora of model guidance now available on the internet it can at times require discussions on the potential for tropical cyclone formation well before the system is developed. Over the weekend several of the global forecast models have indicated the potential for a tropical wave axis currently in the central Caribbean Sea to attempt to develop into a closed surface low pressure system by Wednesday or Thursday over the western Caribbean Sea or the Yucatan. Nearly all of the guidance showing development then brings the system into the southern or central Gulf of Mexico late this week or early this weekend. As mentioned above a deep trough of low pressure will erode the current high pressure ridging along the US Gulf coast potentially allowing any southern Gulf of Mexico tropical system to turn toward the north. Much will depend on when and where the low level center develops as to the future track and impacts of this system across the Gulf of Mexico. Forecasted steering patterns do not look overly favorable for significant TX coastal impacts with such deep troughing likely wanting to sling a system toward the NC or NE gulf coast.  For what it is worth the National Hurricane Center gives the chances of tropical cyclone formation in the western Caribbean Sea or southern Gulf of Mexico at 20% over the next 5 days.  

 

 

 

 

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[wxman57]

Should development occur, it appears that offshore flow along the Texas coast would steer any system well east of Texas.

[Texas Pirate]

Todays disco from Houston NWS (snippet)

LASTLY THE GFS IS TRYING TO DEVELOP A TROPICAL LOW PRESSURE IN
THE NW CARIB ON THUR AND MOVES IT INTO INTO THE GULF FRI/SAT.
GIVEN UPPER LEVEL PATTERN THAT DEVELOPS OVER THE N GULF FOR THE
WEEKEND...SHOULD ANYTHING DEVELOP TROPICALLY IT WILL BE IN A
HIGHLY SHEARED ENVIRONMENT. UPPER LEVEL TROUGH WILL ALSO LIKELY
TAKE THE SYSTEM WELL EAST OF THE AREA TOWARDS FL PANHANDLE ON
SUNDAY. THIS WILL BE SOMETHING TO KEEP AN EYE ON BUT OVERALL NOT
MUCH OF A CONCERN.

[srainhoutx]

RECON has been tasked to investigate the potential tropical disturbance in the Western Caribbean Sea:

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1015 AM EDT MON 12 AUGUST 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 13/1100Z TO 14/1100Z AUGUST 2013
TCPOD NUMBER.....13-073

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA -- WESTERN CARIBBEAN
FLIGHT ONE -- TEAL 70
A. 13/2100Z
B. AFXXX 01BBA INVEST
C. 13/1645Z
D. 12.0N 82.5W
E. 13/2030Z TO 13/2300Z
F. SFC TO 10,000 FT
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

[Rip76]

Sweet....
Sprinklers

[jasons2k]

If anything develops, keep in mind timing could make a big difference. Eric Berger's blog today reminded me of this. What if it's not the day 5-7 time frame, what if it's more like 8-10 days? A lot can change between now and then.

In the short term, more encouraged by the rain potential later this week

[Andrew]

If anything develops, keep in mind timing could make a big difference. Eric Berger's blog today reminded me of this. What if it's not the day 5-7 time frame, what if it's more like 8-10 days? A lot can change between now and then.

In the short term, more encouraged by the rain potential later this week

I agree. How many times have we seen the models develop a storm to early or too late. The trough and coastal low development is always tricky to time. The thing that looks more likely though is that the trough will be on the stronger side for late August.

[unome]

I'm all for this

http://www.cpc.ncep.noaa.gov/products/p ... /index.php

[SusieinLP]

Last two rainmaking opportunities left 0.00 in my yard so I really am not going to get hopeful for this front....and probably N of I10 wil probably have a better chance anyway.

[kayci]

Last two rainmaking opportunities left 0.00 in my yard so I really am not going to get hopeful for this front....and probably N of I10 wil probably have a better chance anyway.

Ditto, Sus......

[Texas Pirate]

Here's some fun news for Wednesday and Thursday in Houston

FROM NWS

THINGS WILL MODIFY QUICKLY OVERNIGHT AS A WEAK FRONT APPROACHES THE REGION FROM THE NORTHEAST. PW VALUES WILL SURGE TO GREATER THAN 2.00 INCHES BY 15Z WEDNESDAY. PW VALUES WILL PEAK TO 2.20 INCHES OVER THE NORTHERN TAF SITES IN THE MORNING AND 2.40 INCHES OVER THE CENTRAL AND SOUTHERN TAF SITES BY AFTN. FCST SOUNDINGS SHOW LITTLE IN THE WAY OF CAPPING AND 700 MB HEIGHT/TEMPS LOWER AND COOL. FEEL RAIN CHANCES WILL BE INCREASE SIGNIFICANTLY ON WEDNESDAY

[Paul Robison]

Last two rainmaking opportunities left 0.00 in my yard so I really am not going to get hopeful for this front....and probably N of I10 wil probably have a better chance anyway.

Ditto, Sus......

What locations are north of I-10? David Paul mentioned "powerful thunderstorms" too? Would north of I-10 get them?

[SusieinLP]

Tomball, The Woodlands, Conroe, Humble....Dallas.

[Paul Robison]

Last two rainmaking opportunities left 0.00 in my yard so I really am not going to get hopeful for this front....and probably N of I10 wil probably have a better chance anyway.

Ditto, Sus......

What locations are north of I-10? David Paul mentioned "powerful thunderstorms" too? Would north of I-10 get them?

Tomball, The Woodlands, Conroe, Humble....Dallas.

My apologies to Ed Mahmoud for my "powerful thunderstorms" question (see quote). But I think everybody should know that I'm not asking specifically for myself but for a personal acquaintance of mine, Dodge, who is a lineman with Center Point Energy. Tomorrow's his day off and I'd hate to see him and his buddies tied up trying to put Houstonians' power back on. What about it, folks? Will he get to enjoy his day off?

[robertscottlazar]

the heat is one thing. but it seems like to me the humidity has been god aweful. you cant even step outside without sweating,ridiculous. is there a reason why the humidity has been so aweful? i remember 2011, it was hot and there was some humidity, but it wasnt nearly as bad as this humidity.

[Paul Robison]

To whom it may concern:

Forget the GFS scenario:

Corpus Christi AF disco:

WITH RESPECT TO THE TROPICAL WAVE OVER THE CARIBBEAN
SEA...THE LESS ORGANIZED SOLUTIONS OF 12Z ECMWF/UKMET/NAM KEEPING
THE SYSTEM AS A TROPICAL WAVE MOVING ACROSS THE YUCATAN AND INTO THE
BAY OF CAMPECHE EARLY FRIDAY AND WEST-NORTHWEST INTO NORTHEAST
MEXICO BY SUNDAY. THE GFS/CMC/NOGAPS CONTINUE SHOW A LOW PRESSURE
AREA SPINNING UP NEAR THE YUCATAN THAT THEN TAKES OFF TO THE
NORTH-NORTHEAST ACROSS THE GULF BUT THESE MODELS HAVE A TENDENCY OF GENERATING A TROPICAL SYSTEM TOO QUICKLY AND THEREFORE DISREGARDED AT THIS TIME. MODELS SHOWS THE UPPER TROUGH AXIS WEAKENING BY MONDAY AND RETROGRADING TOWARD THE COAST AS A SHEAR AXIS TUESDAY. WILL SHOW
SLIGHT CHANCE POPS FOR THE COASTAL WATERS INTO THE COASTAL PLAINS
TUESDAY.

[Katdaddy]

Continuing to slowly organize this morning. Awaiting additional model runs later this morning. Houston-Galveston AFD has nothing to say however the Corpus Christi AFD does make a mention:

SIGNIFICANT FORECAST CHANGES MAY BECOME
NECESSARY OVER THE NEXT SEVERAL DAYS BASED OFF FUTURE EVOLUTION OF
TROPICAL PARAMETERS.

[srainhoutx]

The main focus of attention today through Friday will be the frontal boundary sagging S across Texas. Showers and storms should develop along and N of the boundary mainly N of I-10 and head ESE as the boundary slowly drifts S and pulls up stationary across Metro Houston. Isolated strong to severe storms will be possible later today into this evening across our northern zones while areas SW of Houston remain in an area of drier air and should see lesser amounts of rain. A short wave appears to drop S on Friday and that should end the chances of rain as drier more stable air builds into the Region.

The tropical distiburbance in the Western Caribbean (92L) should begin to head towards the Yucatan on Thursday into Friday. The overnight guidance remain somewhat muddled with the UKMet/CMC and the HWRF suggesting a surface low will develop in Bay of Campeche and head WNW to NW wihile the GFS, GFDL and Euro never develop a closed circulation and move the disturbance N to NE and is picked up by the eastern trough. The NHC has slightly increase the percentages for this disturbance, but there still appears to be some uncertainty as to just how much, if any the disturbanice will actually develop. That said it does appear a weakness may begin to form across the Middle Texas Coast on E into Louisiana as the upper ridge shifts W into the 4 Corners by Sunday into Monday and the eastern trough lifts N. We will see.

[srainhoutx]

Morning e-mail from Jeff:

Focus over the next 24-36 hours will be on incoming front form the north and rain chances. Extended forecast will require focus on the Gulf of Mexico.

Frontal boundary draped across north TX into LA this morning with a few showers and thunderstorms ongoing. Air mass over SE TX is fairly dry, but a significant increase in moisture associated with the frontal boundary is likely from north to south by early afternoon (PWS rising from 1.6 to over 2.0 inches). Upper level ridge is developing westward with 200mb flow turning out of the north and spreading apart which will help in adding lift this afternoon. Slow moving surface boundary and possibly several outflow boundaries will help to add focus for storm development. Storms should begin to develop from the Huntsville to Lake Livingston area in to 1000am to 100pm time period and move S to SSW across much of the area this afternoon into the evening hours. Air mass south of the developing storms will become very unstable by midafternoon ad a few storms could become strong to marginally severe. Main threat would be strong gusty winds. With PWS climbing to over 2.0 inches more organized storms will produce some very heavy rainfall of 1-3 inches per hours. While grounds are parched, this kind of rainfall over an urban area could cause some quick flooding issues.

92L:
An area of showers and thunderstorms accompanied by a westward moving tropical wave has developed over the western Caribbean Sea. Convection this morning on satellite imagery is scattered and while there does appear to be a board circulation there is no well defined closed surface center as of yet. Global forecast models are split on the continued development of this feature and its track into the Gulf of Mexico. Most of the models are showing a closed surface low forming as the system moves over the Yucatan and into the Gulf of Mexico. The troughing expected over the eastern Gulf of Mexico does not appear as deep as in the previous runs and the location development of the Gulf system a little more suppressed to the south suggesting that the eastern US trough may lift out and not fully capture the system. Until a defined low level center is formed any track forecast is really just speculation. There is at least a 30% chance of development with this feature over the next 48 hours and 40% over the next 5 days and by early in the weekend there is potential for a tropical cyclone to be located over the south-central Gulf of Mexico.

93L:
A well defined surface low pressure system has moved off the coast of Africa and is accompanied by an area of showers and thunderstorms. Conditions appear favorable for development and a tropical cyclone may form over the next 24-48 hours as the system moves toward the WNW.

 




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