August 2015 - Isolated Rain Chances to End August

[wxman57]

Taking advantage of the cool weather this weekend to ride up to Beck's Prime in The Heights. It's a bit over 20 miles to Beck's. We'll ride along Buffalo Bayou on the way back home to add another 6 miles on. Back in 5 hours.

[Ptarmigan]

It's been at least a month and a half since we've seen this much rainfall potential in the 7 Day Quantitative Precipitation Forecast. Indeed that pattern has changed. Moisture over the Gulf looks to slowly retrograde West into at least the Eastern half of Texas into mid next week as well as a shear axis meandering along the Northern Gulf Coast drifting toward us. By mid week eyes turn further N as a frontal boundary drops S across the Plains into Texas providing an additional focal point for shower and storm development. Lastly, a tropical disturbance offshore of Mexico may bring its mid/upper level moisture across Northern Mexico into Texas as that front nears our Region. The pesky upper ridge finally looks to be squashed and a strong sub tropical jet moves into Southern California. Fingers crossed we can finally break the 45+ day pattern that brought our very dry and recording breaking heat to bed once and for all.

The Cockroach Ridge has met its end. The subtropical jet is the RAID.

[Paul Robison]

It's been at least a month and a half since we've seen this much rainfall potential in the 7 Day Quantitative Precipitation Forecast. Indeed that pattern has changed. Moisture over the Gulf looks to slowly retrograde West into at least the Eastern half of Texas into mid next week as well as a shear axis meandering along the Northern Gulf Coast drifting toward us. By mid week eyes turn further N as a frontal boundary drops S across the Plains into Texas providing an additional focal point for shower and storm development. Lastly, a tropical disturbance offshore of Mexico may bring its mid/upper level moisture across Northern Mexico into Texas as that front nears our Region. The pesky upper ridge finally looks to be squashed and a strong sub tropical jet moves into Southern California. Fingers crossed we can finally break the 45+ day pattern that brought our very dry and recording breaking heat to bed once and for all.

The Cockroach Ridge has met its end. The subtropical jet is the RAID.

Careful what you wish for, Ptarmigan. NOAA said today:

THE MEDIUM TO LONG RANGE SOLUTIONS DEPICT A CONTINUED WET PATTERN
THROUGH THE END OF THE WEEK...WITH A POSSIBLE TURN TOWARDS SEVERE
ON THURSDAY. A FAIRLY SHARP (FOR AUGUST) MIDWESTERN CONUS TROUGH
PASSAGE LATE WEDNESDAY INTO EARLY THURSDAY WILL INTRODUCE LOWERING
SOUTHERN TEXAS SURFACE PRESSURES AND...WITH AN APPROACHING NORTHERN
TEXAS FRONT HANGING UP JUST NORTH OF THE FORECAST AREA...THE
PROBABILITIES OF STRONGER WEATHER WILL BE ON THE UP AND UP. 31

Memorial Day floods 2.0?

[bikerack]

Memorial Day floods 2.0?

Oh no...I'm fairly certain it will be worse!

[Paul Robison]

Memorial Day floods 2.0?

Oh no...I'm fairly certain it will be worse!

HGX disco repost:

THE MEDIUM TO LONG RANGE SOLUTIONS DEPICT A CONTINUED WET PATTERN
THROUGH THE END OF THE WEEK...WITH A POSSIBLE TURN TOWARDS SEVERE
ON THURSDAY. A FAIRLY SHARP (FOR AUGUST) MIDWESTERN CONUS TROUGH
PASSAGE LATE WEDNESDAY INTO EARLY THURSDAY WILL INTRODUCE LOWERING
SOUTHERN TEXAS SURFACE PRESSURES AND...WITH AN APPROACHING NORTHERN
TEXAS FRONT HANGING UP JUST NORTH OF THE FORECAST AREA...THE
PROBABILITIES OF STRONGER WEATHER WILL BE ON THE UP AND UP. 31

A worse event than Memorial Day, though unlikely, is not out of question, IMHO.

[GBinGrimes]

Paul...the weather apocolypse...although you appear to wish for it and post as if you can conjure it up...is not upon us. Get a grip dude and come in out of left field. We deal with sensible weather FORECASTS, not impending doom. Memorial Day 2015 was an anomoly, the week before us is not. Cut it out.

[Katdaddy]

Thunderstorm chances have arrived as the pattern change is underway. The GOM also looks beautiful this morning with scattered convection

[srainhoutx]

Afternoon briefing from Jeff:

Many weeks of dry weather looks to come to an end this week as strong upper ridge is replaced with fairly impressive troughing for summer.

Upcoming pattern will also open the Gulf to potential tropical influences.

Pattern changes are already underway with the upper ridge having weakened and shifted westward and a downstream upper trough forming over the northern Gulf of Mexico. Satellite images and coastal radars show extensive convection over the northern Gulf of Mexico on the eastern side of the developing upper level trough. PWS over the central and northern Gulf have surged into the 2.0 inch range and this slug of moisture is starting to move inland along the upper TX coast and was sampled by the AM Lake Charles sounding showing a PW of near 2.0 inches.

Expect the Gulf moisture to continue to progress inland as the upper trough moving slowly westward which will support an active seabreeze front this afternoon. Best rain chances will be coastward of US 59 with more isolated activity inland. Better moisture will be in place on Monday and expect more widespread coverage of storms along the seabreeze and an earlier start to the activity.

Mid week pattern favors the formation of an unusually strong mid latitude trough for middle August and the southward advance of a decent cold front with this trough. Upper ridge along the US west coast amplifies and results in deep downstream trough formation over the central US. Cold front will arrive into TX Tuesday and likely stall near/over SE TX on Wednesday into Thursday. Deep tropical moisture will remain in place along and ahead of this feature and support a good chance of wetting rainfall over a large portion of the region. Could see a severe threat with this front since the jet dynamics will be displaced far south for August. Chances for organized rainfall also increase during this period…not looking at flooding rainfall, but certainly heavy rainfall will be possible.

Tropics:
Tropical wave moving slowly westward north of the Caribbean Sea this morning continues to experience strong wind shear. Overall upper air pattern will undergo transition in support of deep layer ridging developing from the central Atlantic into the SE US or a long fetch ESE to E steering flow from the deep tropics into the Gulf of Mexico over the next several days. We will have to closely watch incoming tropical waves from the east as they will likely be trapped under the building ridge and head generally toward the Gulf of Mexico. While conditions over the Atlantic remains modest at best, the Gulf looks fairly favorable over the next week or so.

96L over the far eastern Atlantic is showing some weak signs of organization this morning and NHC currently gives the system a 40% chance of development as it moves generally westward over the next 5 days. There is some weak model support for formation of this system, but thus far this season the El Nino enhanced shear has ended the chances of systems in the deep tropics.

[wxman57]

Looks like the wet pattern is developing across SE TX, just as the models were predicting a week ago. I've measured 1.6" of rain in SW Houston over the past week. More to come this week, maybe a lot more.

With the heat trailing off, I'll be flying to Sunnyvale, CA in the morning for some meetings. I may need my coat - lows in the upper 50s and highs in the low 80s. BRRR!

[srainhoutx]

Safe travels wxman57. I will be flying out Tuesday morning to Oahu/Honolulu for 7 nights and certainly will not need a coat.

[unome]

anyone else watching the gulf?

http://www.met.nps.edu/~mtmontgo/storms ... antic.html

http://www.met.nps.edu/~mtmontgo/storms2015/P23L.html

[Cromagnum]

Wish we would get something south of Hwy6. We hit .15 inches this morning and that's all we have seen in 1.5 months. Every rain storm from the north splits in half once it gets south of downtown and misses us both East and West. Very frustrating as I've watched it do this 3 or 4 times this week already.

[Ptarmigan]

anyone else watching the gulf?

http://www.met.nps.edu/~mtmontgo/storms ... antic.html

http://www.met.nps.edu/~mtmontgo/storms2015/P23L.html

It is a tropical wave over Gulf of Mexico. It is tagged as Pouch 23L.

[Texaspirate11]

anyone else watching the gulf?

http://www.met.nps.edu/~mtmontgo/storms ... antic.html

http://www.met.nps.edu/~mtmontgo/storms2015/P23L.html

It is a tropical wave over Gulf of Mexico. It is tagged as Pouch 23L.

Can you please define what a Pouch is?
Thanks.

[Katdaddy]

The pattern change arrived yesterday. Rain and thunderstorm chances will remain high through the week. This morning's radar image already shows scattered thunderstorms just offshore of the Upper TX Coast. Invest 96L SW 0f the Cape Verdes has a 70% chance for tropical development during the week.
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
458 AM CDT MON AUG 17 2015

TXZ163-164-176>179-195>200-210>214-226-227-235>238-181000-
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-MADISON-MATAGORDA-
MONTGOMERY-POLK-SAN JACINTO-TRINITY-WALKER-WALLER-WASHINGTON-
WHARTON-
458 AM CDT MON AUG 17 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT

ISOLATED STRONG THUNDERSTORMS ARE POSSIBLE TODAY. THE MAIN
HAZARDS EXPECTED ARE STRONG GUSTY WINDS AND HEAVY DOWNPOURS.
SOME OF THE STRONGER STORMS COULD PRODUCE 1 TO 2 INCHES VERY
QUICKLY. STREET FLOODING MAY BE THE MAIN IMPACT IN URBAN AREAS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

SCATTERED THUNDERSTORMS ARE EXPECTED MAINLY FROM MONDAY THROUGH
THURSDAY. STRONG GUSTY WINDS AND CLOUD-TO-GROUND LIGHTNING ARE
POSSIBLE. BRIEF HEAVY RAINFALL WILL ALSO BE POSSIBLE AND COULD
LEAD TO STREET FLOODING IN URBAN AREAS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED TODAY AND THIS EVENING.

[Rip76]

A little action in the BoC this morning?

[unome]

Can you please define what a Pouch is?
Thanks.

It is well-defined here: http://met.nps.edu/~mtmontgo/marsupial.html

Guidance From The "Marsupial Paradigm" of tropical cyclogenesis from easterly waves

"Marsupial" tracking is a real-time, experimental forecast product to track the wave "pouch" and predict the tropical cyclogenesis location using global model operational data.

The product is based on the marsupial paradigm for tropical cyclogenesis presented in a recent study by Dunkerton, Montgomery and Wang 2008 (EGU's Atmospheric Chemistry and Physics, hereafter DMW08). The marsupial paradigm indicates that the critical layer of a tropical easterly wave is important to tropical storm formation because

Hypothesis 1:
Wave breaking or roll-up of the cyclonic vorticity near the critical surface in the lower troposphere provides a favored region for the aggregation of vorticity seedlings and TC formation;
Hypothesis 2:
The wave critical layer is a region of closed circulation, where air is repeatedly moistened by convection and protected from dry air intrusion;
Hypothesis 3:
The parent wave is maintained and possibly enhanced by diabatically amplified mesoscale vortices within the wave.

It has been shown in DMW08 and Wang, Montgomery and Dunkerton (2009, GLR) that genesis tends to occur near the intersection of the critical surface and the trough axis of the precursor parent wave, which is the center of the pouch.

The objective of marsupial tracking is to track the wave pouch (rather than the diabatic vortices inside the pouch), estimate its propagation speed and predict the genesis location, which can be used to provide useful guidance for flight planning during the NOAA hurricane field campaign as part of NOAA/IFEX and the upcoming field experiments NSF-PREDICT and NASA-GRIP in summer of 2010.

USA Today recently published an article on the research being done on the new paradigm of marsupial theory. A copy of the article that appeared in the print version is available for download as a PDF file.

USA Today article: http://usatoday30.usatoday.com/weather/ ... ouch_N.htm

thumbnail of current surface analysis with their "pouches" overlaid


just because they are tracking something, doesn't mean a TD will form, but since they have better credentials than I, I watch what they watch

Their latest synopsis of what they are watching can be found here: http://www.met.nps.edu/~mtmontgo/synopses2015/

[unome]

A little action in the BoC this morning?

lower pressures down there





CMC & GFS note something on the day-5 loop: http://ruc.noaa.gov/hfip/tcgen/

NHC doesn't see development thru 72-hrs though

[srainhoutx]

32 years ago this morning the Houston/Galveston area woke up to a Category 3 Hurricane nearing the Upper Texas Coast. Some of us remember vividly the complex of thunderstorms that rolled off the Alabama Coast and quickly developed a surface low and began moving our direction is short order. Even in an El Nino year, Hurricane Alicia serves as a reminder that it only takes one in a slow year to make for a very bad Hurricane Season.

[BlueJay]

We are currently receiving a nice little summer shower! Yeah!!!!