SE TX/SW LA weather: Much cooler and WET after Tuesday

[srainhoutx]

Morning e-mail from Jeff Lindner...

90L:

Strong tropical wave/area of broad surface low pressure south of the Cape Verde Islands continues to show signs of development this morning. IR images along with first light visible shows a broad circulation with modest deep convection mainly on the western and NW side of the system. Conditions are favorable for development and TD # 3 could form within the next 24-36 hours.

Track:

Sub-tropical ridging is building north and northwest of 90L and this will result in a steady westward motion over the next several days. Guidance is in near excellent agreement on a westward track for the next 3-4 days with the GFS, CMC, HWRF, and GFDL nearly on top of each other. After that the respected EURO shows a strong recurve out to sea with a weaker ridge to the north while none of the other global models suggest such a strong turn. In fact the GFS and HWRF which were suggesting a more slight turn yesterday have lost any sign of a recurve in their 00Z runs. A significant tropical cyclone could be approaching the Leeward Islands, the US Virgin Islands, and Puerto Rico in the next 5 days.

Intensity:

90L is very large and will take a little time to firm up a well defined closed center. The global models continue to be extremely aggressive with this feature with the GFDL taking the system to 973mb and the HWRF tanking it out at 928mb and 111 kts. The SHIPS intensity guidance brings the system to a 60kt TS in 48 hours and then nearly a major hurricane in 120 hours. The NOGAPS is the only model that really does not develop the system much. The intensification in the front end may be quick and aggressive on SHIPS since the circulation is broad, however once well defined, factors appear satisfied for a period of rapid intensification.

Note:

With guidance widely available via the internet everyone must be reminded that the guidance is just a model and one should not focus on the longer range Day 5+ periods with great certainty. Such periods are better used for overall large scale steering patterns and not exact tracks and landfall locations. For example at the end of their respective runs the EURO has the system nearing the Canadian Maritimes while the GFS shows a north-central Gulf of Mexico hurricane.

Local Weather:

Another active day yesterday with numerous areas getting wetting rains once again. Evening soundings yesterday showed copious moisture remains across the SW and W parts of the area with much drier air mass NE of the area. Once trigger temps. in the mid 90’s are reached today expect another round of thunderstorms mainly W of I-45 and S of I-10. We should see less coverage today than yesterday, but some will get wet.

Ridging builds Saturday and Sunday with lower rain chances mainly limited to the seabreeze.

Early next week – Tropical wave over the SE Bahamas and eastern Cuba moves WNW into the Gulf of Mexico and heads in the general direction of the TX/LA coast. GFS brings the wave axis across the area on Tuesday on the back side of a westward moving TUTT low into S TX. We should see PWS surge back to 2.0 inches by early Monday making for favorable seabreeze activity, then more widespread development Tuesday and Wednesday as deep moisture is firmly entrenched.

By next week (Aug 22) eyes turn toward the east as what becomes of 90L will be moving potentially just north of through the Caribbean Islands.

[Yankeegirl]

I actually got a few drops this afternoon from the one little storm to my south.... They must have blown over here or something? I wonder if any of these tropical things are going to improve the rain chances here?

[jasons2k]

From Jeff:

TD Ana:

I am hard pressed to call Ana even a tropical depression this morning. As she passed through the Leeward Islands overnight…there were no west wind reports and current long radar Doppler radar out of Puerto Rico does not reveal any kind of surface circulation. I suspect the low level center has spun down and Ana is no longer a defined tropical cyclone, but instead a sharp tropical wave. NHC will likely discontinue advisories at 1000am. The system continues to race WNW at nearly 30mph and this combined with dry air and weak SSW wind shear is resulting in a negative environment for development.

Track:

Not a lot to be said here as there is no surface center to track. There is little to no guidance suggesting Ana survives the track over Hispaniola. NHC is taking a strong tropical wave into the SE Gulf of Mexico by the end of the week before it is pulled northward by an unusually strong August trough.

Intensity:

I doubt Ana will make much of a comeback after passing along the mountainous islands of the northern Caribbean. I have seen much stronger hurricanes struggle to survive. No model guidance suggest much intensification and in fact most of them lose the system altogether.

Hurricane Bill:

First hurricane of the 2009 season forms in the central Atlantic. Bill is a well defined tropical cyclone with deep convection (cloud tops to -80C) over the center and extensive banding features. Bill is also a very large tropical cyclone per satellite images.

Track:

Guidance except for the UKMET is in near excellent agreement on Bill tracking WNW for the next 2-3 days before a weakness in the ridge over the central ATL develops a NW and NNW motion. The UKMET remains a southern outlier…however this model has trended northward from yesterday. Guidance continues to shift right (eastward) and this trend may continue. On this track the only potential impact would be to the island of Bermuda.

Intensity:

Bill is a large hurricane with a developing inner core. Current intensity of 75mph is likely on the lower side and Bill could be slightly stronger. There is little to impede intensification and all the model guidance agrees that Bill will become a major hurricane. NHC brings the system to 105kts (and this may be conservative). There is at least a 30% chance of an increase of 30kts per the SHIPS rapid intensification methods.

TD Claudette:

TS Claudette made landfall near Fort Walton Beach, FL just after midnight with 50mph winds. The surface center is tracking NW into Alabama and will move into MS today. Heavy rains of 4-8 inches along the path are likely.

Local Weather:

Deep tropical moisture associated with an inverted trough over the western Gulf of Mexico will surge inalnd today. PWS will rise significantly to well over 2.0 inhces this morning. Radar shows numerous showers and thunderstorms across the coastal waters and first teir coastal counties starting to push inland. Expect widespread coverage today of thundersotrms along the seabreeze. Will see a repeat Tuesday and Wednesday as deep moisture remains in place.

Toward the end of the week a highly unusual upper air pattern develops with strong eastern US trough developing and a decent cold front progged to head for the area. Models take the front off the coast…however it is August and a more likely solution would be to stall it inland. For now will uptick rain chances Friday and then bring in a dreir air mass for the weekend. Could see ovennight lows fall into the 60’s by Sunday AM if the front does clear the area.

This strong trough should be the player to keep both Ana and Bill well east of our area.

[Flyinman]

WHOA, better make sure my heater works if it actually gets into the 60's ...I hope we are lucky enough to see more rain and cooler temps in a one week span.

[srainhoutx]

Maybe it will cool my pool down from 93 degrees.

[Yankeegirl]

The 60's??!! what are those?? I guess I am going to have to wash the flannel sheets....

[vbhoutex]

Gonna have to bring out the sprinklers again tomorrow if the weather doesn't cooperate. Our 40% today was a total bust for most of the area. Managed another 100ºf day here at the house. C'mon 60's!!!

[mpic]

I'll believe it when I see it! ABC 13 has the lowest forecast this week for 73 with an 81 heat index.

[srainhoutx]

Morning e-mail from Jeff...

Rain chances remain high today and Wednesday as Gulf of Mexico remains wide open.

Tropical wave axis is along the coast this morning and will move inland today. Radar shows numerous showers and thunderstorms along the coast and offshore moving inland. PWS have increased into the 2.2-2.3 inch range along with mid level cooling and would expect to see a rapid increase in coastal county/inland convection once trigger temps. in the mid 80’s are reached. Should see more widespread coverage today versus yesterday as the air mass is very moist. Main concerns will be very heavy rainfall with excessive PWS values and deep mean RH at or above 70% through a very deep layer. May see a few locations get a quick 2-3 inches in 30 minutes. Lack of defined surface boundary should keep convection scattered in nature and moving preventing any major flooding issues.

Should see a repeat Wednesday and maybe Thursday as deep tropical tap remains aimed at the TX coast. Massive trough carves out over the Great Lakes after Wednesday sending a fairly strong cold front for August southward. Boundary should reach SE TX early Friday and move across the area during the day…likely driven more by convective outflow boundaries than the synoptic scale pattern which would hand it up in our northern counties. Will bite on the front making it into the coastal waters by early Saturday with a dry air mass with lower dewpoints filtering in from the NE. Will still see warm afternoon highs in the mid 90’s over the weekend, but humidity values will be reduced and overnight lows may fall into the 60’s in some locations.

Hurricane Bill:

IR and visible satellite images indicate Bill has developed an inner core with a defined eye and thick CDO surrounding the center. Visible images show the eye clearing out and Bill will likely be upgraded to a major hurricane on the next advisory package.

Track:

Bill is moving at 285 degrees or WNW at 17mph and this motion is forecast to continue for the next 24-48 hours. Model guidance is in good agreement that a weakness in the sub-tropical high around Bermuda will impart a more NW motion to Bill after 48 hours. Thereafter a powerful deep layer trough digging across the Great Lakes into the east coast should capture Bill and recurve the hurricane out to sea. It is still too early to tell if Bill comes close enough to impact Bermuda or the NE US. Guidance has shifted rightward (east) the last few runs indicating a bigger threat to Bermuda and a lesser threat to the NE US.

Intensity:

Bill is likely already a major hurricane and there is little to impede intensification. Will go with the more aggressive guidance and take Bill to a category 4 hurricane given the very good satellite appearence and development of an inner core. All guidance keeps Bill at or above major hurricane status through day 5 even with slightly increasing wind shear. The forecasted S to SSW wind shear in the later periods may be negated by an increasing forward speed resulting in a net small increase in shear of the storm.

Ana Remains:

The remains of Ana continue to race westward and are located in the southern Bahamas and along the north Cuban coast this morning. Radar out of Cuba and FL along with visible satellite images do not suggest that Ana is regenerating at this time.

[jasons2k]

I got .54" in today's storms. Not bad but I sure could use some more!

[Yankeegirl]

Not one drop of rain for me today!!

[vbhoutex]

We had a brief shower, but it barely wet the roads or the ground for that matter. At least the clouds kept the temps down today.

[srainhoutx]

Just got a very light sprinkle from the "left overs" last evening. Morning e-mail from Jeff this morning offers more hope though.

Deep tropical moisture remains in place across the region with PWs values at or above 2.0 inches. Water vapor and IR satellite along with GPS data show yet another surge of tropical moisture moving northward from the Bay of Campeche that will arrive into the area this afternoon. Gulf is not as active this morning in the nearshore waters, however believe once trigger temps in the upper 80’s are achieved (1000-1100am) we will start to see showers and thunderstorms develop. I have noticed the last two days a meso boundary setting up each afternoon in the coastal counties resulting in near continuous thunderstorm development as the boundary interacts with the deep southerly flow. This boundary has been found from Bay City to Texas City to Winnie…nearly in the same spot the last two afternoons. We shall see if it is there again today.

Given the fairly moist Gulf rain chances look decent again on Thursday and then up again Friday into early Saturday as an unusual cool front for mid August pushes into and possible across the area. Expect to see numerous thunderstorms develop Friday PM into Friday night as the front begins to move into the area. Much drier air mass with dewpoints into the 60’s will be common this weekend. Overnight lows may fall into the 60’s at several sites Sunday AM.

Hurricane Bill:

Bills intensifies into a powerful category 4 hurricane.

IR and visible images this morning show a well defined mature hurricane with a 25-30 mile diameter eye within a ring of deep convection. Convective cloud tops have weakened since earlier this morning and the pattern on IR and WV images suggest SW shear is affecting the hurricane with high level clouds spilling off to the NE and outflow restricted to the SW. The entire storm appears to be taking on a SW to NE tilt suggestive of wind shear. Additionally the hurricane may be undergoing an eyewall replacement cycle and the next aircraft will be in this morning to determine intensity and if a double wind maximum is found.

Track:

Guidance has shifted ever so slightly westward overnight, but remains in near excellent agreement on the large deep layer east coast trough turning Bill north and northeast well east of the US mainland…although coastal Canada may not be as lucky. The GFS shows a harder right turn in the longer periods while the CMC tracks the storm close to the SE Canada coast. The other item of interest is how close to Bermuda the hurricane comes…right now it will pass a good distance to the west…but the error is clearly within the threat of a direct hit.

Intensity:

Bill is a well developed hurricane. As mentioned above SW wind shear appears to be eating away at the outflow on the SW flank, however Bill should overcome this in about 12 hours or son according to the models. Conditions remain favorable along the forecast track for the next 2-3 days to maintain the system as a major hurricane. After that time Bill should begin to encounter increasing wind shear from the SW ahead of the east coast trough. With all that Bill could approach the SE Canada coast as a hurricane.

[Yankeegirl]

No rain here today.... again.... im sick of all these "good" chances of ran and get squat!! Oh well....

[vbhoutex]

We had a brief shower, but it barely wet the roads or the ground for that matter. At least the clouds kept the temps down today.

[Flyinman]

Yankeegirl, I agree!! It does look like we have a "decent" chance Friday with the front working this direction. I am hoping Friday is the day.

[srainhoutx]

Morning e-mail from Jeff...(breaks out thermals and prepared to open the windows if it verifies )...

Slightly drier air mass over head this morning as deep tropical moisture is found out of over the Gulf of Mexico and across N TX. Cold front currently located over N OK is moving southward with forcing from a deep upper trough over the northern US. This upper trough will push eastward this weekend pushing the front into SE TX Friday. This same trough will save the US east coast from a direct impact from Hurricane Bill.



Still enough moisture around today for scattered seabreeze convection to get going this afternoon. Trigger temperatures are higher today (lower 90’s) so expect a later start to the activity. Most favored areas will be our SW counties where upper support from a northward moving wave will impact.



Front arrives into the area tonight and Friday…pushing across the area Friday afternoon. This will match up well with peak heating and a tropical air mass…so Friday is looking fairly wet. Front is forecast to reach the coast late Friday and at this time I see no reason as to why it would not. Will see a much drier air mass filter into the region starting early Saturday with progged dewpoints as low as the upper 50’s across our northern zones and mid 60’s elsewhere. Overnight lows Sunday could fall into the low 60’s up north to around 70 along the coast…a nice break from the near 80 degree lows over the past 2 months.



Hurricane Bill:



NOAA research aircraft were in Bill yesterday and the next plane is currently enroute this morning. Earlier this morning the large eye of Bill passed about 75 miles SW of NOAA buoy 41044 which recorded sustained winds of 77mph with a gust to 92mph. Rapid scan satellite operations yesterday also revealed meso-vorticies rotating within the eye/eyewall of Bill…common in well developed powerful hurricanes. Such vortices are caused by the stretching vertically of the tremendous horizontal vorticity located between the eye and the eyewall where wind speed changes between the calm eye and peak winds in the eyewall are found. This horizontal vorticity is stretched by powerful updrafts within the eyewall that can lead to rapid but brief spin-up know as mini-swirls. This phenomena was discovered in 1992 after Hurricane Andrew crossed S FL. Mini-swirls only last 1-10 seconds, but can increase wind speeds by as much as 40-60mph in addition to the background maximum sustained wind causing incredible damage in a very small area. This was noted in Andrew by short streaks of near total devastation less than a mile long and about 100 feet wide next to structures that only lost parts of the roof.



Track:

Guidance continues in great agreement that Bill will enter into the weakness in the sub-tropical ridge west of Bermuda and gradually turn toward the N and NNE. The NOGAPS and UKMET are the farthest west and show the closest approaching to coastal New England while the HWRF and BAM models are on the right side of the guidance envelope. The GFDL is nearly down the middle and NHC is currently splitting the difference with the forecast track. On this track Bill should remain off the New England coast…but may be close enough to bring TS force conditions to some areas.



Intensity:

Dropsondes yesterday indicated significant amounts of dry air were being ingested into the inner core of the hurricane and it is somewhat surprising to Bill looks as good this morning given such intrusions and weak westerly wind shear. SST’s are very warm and the weak shear is forecast to abate allowing ideal conditions for intensification. Bill should maintain major hurricane status as he tracks northward over the western Atlantic. In about 3-4 days Bill will be crossing into the colder waters off the north Atlantic…however upper level conditions on the east side of the upper trough over the eastern US will help maintain a much stronger hurricane than one would expect in part due to the upper level divergence forecast over the system. Hence the potential strike on coastal Canada could be a good one.

[southerngale]

Thermals? After seeing your electricity bill, I bet you and I never turn off our air conditioners! lol

Our lowest lows (as of now) are only 69F for Sunday night and Monday night. I'll be impressed when I get some of those 50's mentioned in Jeff's email. heh

[weatherguy425]

Unfortunetly I think he means dew points may be in the 50's...

[SaskatchewanScreamer]

Forget the heaters........put an extra blanket on your bed, open your windows, and have a wonderful nights sleep (my husband has ours open a crack when it's -20F......the sleeping part is great but boy it's a shock to the system when one has to get out from under the covers).