Rains return to SE Texas by mid-week 7/26/07

[ticka1]

http://www.hpc.ncep.noaa.gov/qpf/95e12p48iwbg_fill.gif

[longtalltexan79]

Oh how I wish the weather could be like today, everyday...it was so pleasant up here in Livingston...

Rain, Rain GO AWAY!! I know the rain and cloudiness have alot to do with my bouts of depression lately...it's just a downer it has to rain so much during the summer :(

[ticka1]

Latest email from JeffL:

After a few dry days heavy rains will return today and really ramp up Thursday and Friday.

Discussion:

Upper trough as once yet developed over C TX with surge of deep tropical moisture associated with a tropical wave moving NW across the Gulf of Mexico. Weak frontal boundary that passed through the area Sunday is retreating NNE this morning and currently extends from near Columbus to W Galveston Island. Moist and unstable air mass SW of this boundary will surge into the rest of the area by early afternoon with showers and thunderstorms developing. Models are aggressive in surging 2.2-2.4 inch PWS into the area overnight and given the looks of GPS sounder over the Gulf and the water vapor this seems reasonable. Expect numerous showers and thunderstorms to be the result Thursday through Sunday as upper trough only moves from near San Antonio to the Rio Grande in that time period.

Given deep moist profile, high PWS, and good upper air divergence the threat for heavy to excessive rainfall is high the next 48-72 hours. Average rainfall amounts of 2-4 inches will be common by Saturday with isolated totals of 4-6 inches…would not be surprised if somebody picked up a quick 10-12 inches during that same time. Similar patterns this summer over TX have produced some very impressive short term rainfall totals.

Tropics:

NAM continues to spin up a tropical storm over the western Gulf of Mexico and track it toward the TX coast. Latest run shows a 1003mb surface low moving inland along the upper TX coast Saturday. GFS nor any other global models with the exception of the CMC are showing any development in this area. The NAM is usually a poor tropical model…with that said there has been a nice expansion and deepening of thunderstorms this morning over the Bay of Campeche. I would not be all that surprised to see a surface low attempt to develop over the western Gulf of Mexico given a decently favorable position of the tropical wave axis SE of the upper trough over TX…which could help vent convection. NAM is likely way overdone and the end result will still be nearly the same…lots of rainfall over TX. Should anything tropical try to spin up wind/seas/tides will need significant adjustments.

[Texas SpeedDiva]

Just keep telling yourself as bad as all the rain is it's keeping the 'canes away. Who cares if everything has mildew and mold and I'm getting webbed feet.

[BaytownWeatherWatcher]

Just keep telling yourself as bad as all the rain is it's keeping the 'canes away. Who cares if everything has mildew and mold and I'm getting webbed feet.

true. thanks for the reminder.

[archergirl66]

Yeah, but all this rain is killing our business!! And I love my job. :( Stupid rain needs to stop! :growl:

[ticka1]

afternoon AFD out from HOU/GAL WFO. Sounds interesting to say the least...


000
FXUS64 KHGX 251947
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
247 PM CDT WED JUL 25 2007

.DISCUSSION...
SCATTERED SHOWERS AND A FEW THUNDERSTORMS MOVING IN OFF THE GULF
AND INTO THE COASTAL COUNTIES. IMPRESSIVE CLUSTERS OF STORMS OVER
CRP/BRO CWA BORDER. MOISTURE RECOVERING QUICKLY WITH 1.5" PW OVER
THE CWA RISEN TO THIS MORNING AT LFK HAD 1.06" AND VCT 1.99" AND
BY 2 PM STILL HIGHER. LL FLOW STRENGTHENING AS WELL AS UPPER SW
FLOW ACROSS SETX. VERY IMPRESSIVE MASS OF SHRA/TSRA OVER THE
BAY OF CAMPHECHE AT 18Z...GOING THROUGH SOME FLUCTUATIONS BUT IT
DOES HAVE SOME STRONG UPPER LEVEL VENTILATION ON THE NORTH SIDE AS
THIS FLOW OVER SETX/LA STRENGTHENS THIS AFTERNOON AND TONIGHT.
WITH THIS ASIDE VERY IMPRESSIVE PW OVER THE WESTERN GULF WILL BE
SPREADING NORTH AND SHOULD EDGE INTO THE CWA TONIGHT AND THURSDAY.
2.2 TO 2.5" PW WILL BE OVER THE REGION BY THURSDAY NIGHT AND
FRIDAY ADDING TREMENDOUSLY TO THE THREAT OF VERY HEAVY RAINFALL.(NAM PROGS PW NEAR 2.65") SEEMS LIKELY THAT FLASH FLOOD WATCH WILL
BE NEEDED EITHER THURSDAY OR THURSDAY NIGHT SO FOLLOWING SHIFTS
MAY BE ISSUING ONE. (IF THE NAM IS CORRECT WITH THE FORECAST OF
THIS GULF SYSTEM GETTING ORGANIZED RAIN THREAT WOULD BE EVEN
HIGHER.) SO FAR THE GFS IS JUST PROGGING A BIG INCREASE IN
MOISTURE WITH NO ORGANIZATION. TPC ON THE SAME PAGE WITH
IMPRESSIVE UPPER SUPPORT FOR THIS SURGE (SEE RECENT TWDAT). THE
SURGE OF MOISTURE WILL BE IN PLACE THROUGH SATURDAY AND PERHAPS
SUNDAY. STAY TUNED ON THIS.

IN THE EXTENDED THE MOISTURE SLOW DRIES OUT SUNDAY-TUESDAY AS
UPPER RIDGE BUILDS SOUTH THROUGH TEXAS AND ANOTHER FRONTAL
BOUNDARY PUSHES DOWN INTO TX/LA.

WITH ALL OF THE RAIN SHOULD COME SOME LOWER TEMPERATURES AND
ABUNDANT CLOUD COVER THROUGH THE WEEKEND.
45

[longtalltexan79]

The radar is really lit up west of us....I'm thinking even if the thing in the BOC doesn't develop into something tropical it's still going to mean a hellava lot of rain for us...

I think we're just going to have to resign to the fact it's not going to stop raining anytime soon...but like it has been said at least it's keeping the canes at bay for the time being...I'd rather much have this rain then a Cat 3 or 4 storm come blasting through!

[ticka1]

Thursday Morning email from JeffL:

Threat for very heavy rainfall and flooding on the increase

Flash Flood Watch issued through tonight for: Austin, Washington, Wharton, Colorado, Matagorda, and Jackson counties.

River Flood Watch issued for all area rivers through Saturday evening

Discussion:

Classic flash flood set up unfolding across coastal TX over the next 48 hours as slow moving upper low over C TX interacts with a strong tropical wave over the W Gulf of Mexico. Somebody is going to get a lot of rainfall in the next 2 days…3 day totals may top out over 15 inches across the coastal bend. Upper low near and west of San Antonio is nearly stalled out his morning providing deep S to SSW steering flow into SE TX from the W Gulf. Tropical wave is noted running 200 miles E of Brownsville with another flare up this morning. GPS sounder shows PWS values have increased to near 2.3 inches around Matagorda Bay and are forecast to rise to near 2.5 inches by tonight. Upper low near SAT will provide favorable lift and divergence aloft to maintain very high rainfall chances and lift/squeeze out deep tropical air mass advecting inland from the Gulf.

NAM continues to spin up a tropical storm and landfall it along the middle/upper TX coast….given the 30-40kts of upper air wind shear over the tropical wave there should be little to no development of this system. However, both the GFS and especially the NAM show tremendous moisture advection into SE TX this evening and all day Friday pointing to a potential excessive rainfall event in a S to N band. NAM is likely overdone as it focuses the rainfall more like a Tropical Cyclone would and this is not what is likely to happen given that there is not a tropical storm in the Gulf at the moment. Both models are pegging the area with 5-8 inches of rainfall by early Saturday.

Rainfall Amounts:

Given saturated profile, PWS well over 2.0 inches, and likelihood of warm rain production some very impressive rainfall totals are likely. Hourly rainfall rates of 2-3 inches with amounts up to 5 inches will be possible. Widespread amounts over the next 24 hours will likely average 2-4” with isolated amounts of 6-8”. Heaviest amounts are likely today around Matagorda Bay and Friday along I-45.

Given saturated grounds and still high rivers rainfall of this magnitude will no doubt cause flooding problems.

Extended:

Seemingly endless rainy pattern looks to continue through much of next week with maybe a brief drying Monday and Tuesday before the pattern repeats again as it has done so many times this summer over TX.

Tropics:

Tropical wave continues to flare in the central/western Gulf of Mexico. 40kts of upper level shear however are keeping the wave from developing this morning. Unless shear weakens unexpectedly there should be no development.

Global models are starting to indicate lowering pressures in the tropical Atlantic off the coast of Africa and some develop in this region over the next 10 days is possible

[archergirl66]

The latest forecast discussion:


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1014 AM CDT THU JUL 26 2007

.DISCUSSION...
WILL MAKE A FEW FIRST PERIOD FORECAST ADJUSTMENTS BASED ON CURRENT
RADAR TRENDS...BASICALLY BLANKETING ALL OF SOUTHEAST TEXAS WITH LIKELY
POPS FOR THIS AFTERNOON. STRONGEST STORMS AT MID MORNING WERE TO THE
EAST OF THE HOUSTON AREA RIGHT AROUND LA PORTE. HARRIS COUNTY OEM RAIN
GAGES IN THIS AREA HAVE RECORDED RAINFALL RATES AS HIGH AS 0.87" IN
FIFTEEN MINUTES! IT`S GOING TO BE DIFFICULT TO PINPOINT EXACTLY WHERE
THE HEAVIEST RAINFALL WILL BE DURING THE AFTERNOON HOURS DUE TO SOME
STABILIZATION TAKING PLACE AT THIS TIME. IT APPEARS BASED ON CURRENT
RADAR TRENDS THAT OUR FAR WESTERN COUNTIES THAT ARE ALREADY IN THE FLASH
FLOOD WATCH UNTIL MIDNIGHT ARE AT GREATEST RISK. WE WILL NEED TO ADDRESS
THE POSSIBLE EXPANSION OF THE WATCH FURTHER EAST IN THE AFTERNOON PACKAGE.

PRECIPITABLE WATER VALUES ARE ALREADY OVER TWO INCHES AND ARE FORECASTED
TO RISE EVEN MORE. WITH THE NEARLY STATIONARY UPPER LOW OVER SOUTH CENTRAL
TEXAS AND THE VERY DEEP TROPICAL MOISTURE JUST OFFSHORE...BOTH LOW LEVEL
CONVERGENCE AND UPPER LEVEL DIVERGENCE ARE EXPECTED TO INCREASE
SIGNIFICANTLY LATER TONIGHT. THIS STILL HAS THE POTENTIAL TO BE A VERY
DANGEROUS FLASH FLOOD EVENT FOR PORTIONS OF OUR AREA OVER THE NEXT TWO
DAYS. STAY TUNED!

[Texas SpeedDiva]

I had to go to a client's office and office of opposing counsel yesterday. In my travels I went over White Oak and Buffalo Bayous. I was surprised at how high they still are. I expected them to be up. But they were really up higher and with a faster current than I anticipated. So more rain won't bode well for that.

[ticka1]

So it begins:
Flash Flood Watch

FLOOD WATCH
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
944 PM CDT THU JUL 26 2007

TXZ200-212>214-227-237-238-271045-
/O.EXB.KHGX.FF.A.0007.000000T0000Z-070727T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z. OO/
BRAZORIA-CHAMBERS-FORT BEND-GALVESTON-HARRIS-LIBERTY-WALLER-
INCLUDING THE CITIES OF...ALVIN...ANAHUAC...ANGLETON...
BROOKSHIRE...CLEVELAND...DAYTON...FREEPORT...FRIEN DSWOOD...
GALVESTON...HEMPSTEAD...HOUSTON...HUMBLE...KATY... LAKE JACKSON...
LEAGUE CITY...LIBERTY...MISSOURI CITY...MONT BELVIEU...PASADENA...
PEARLAND...PRAIRIE VIEW...RICHMOND...ROSENBERG...SUGAR LAND...
TEXAS CITY...TOMBALL...WINNIE
944 PM CDT THU JUL 26 2007


...FLASH FLOOD WATCH IN EFFECT UNTIL 6 AM CDT FRIDAY...

THE NATIONAL WEATHER SERVICE IN HOUSTON/GALVESTON HAS EXPANDED
THE

* FLASH FLOOD WATCH TO INCLUDE A PORTION OF SOUTHEAST TEXAS...
INCLUDING THE FOLLOWING COUNTIES...BRAZORIA...CHAMBERS...FORT
BEND...GALVESTON...HARRIS...LIBERTY AND WALLER.

* UNTIL 6 AM CDT FRIDAY

* DEEP TROPICAL MOISTURE WILL STILL RESIDES OVER THE REGION. A
FAVORABLE UPPER LEVEL WIND PATTERN...AN APPROACHING UPPER LEVEL
DISTURBANCE FROM THE WEST AND A SURFACE BOUNDARY SITUATED ALONG
THE INTERSTATE 10 AND HIGHWAY 59 CORRIDOR WILL LEAD TO
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS OVERNIGHT.
THOUGH LOCALLY HEAVY RAIN IS POSSIBLE ACROSS THE ENTIRE WATCH
AREA...THE HEAVIEST WILL TEND TO ACCUMULATE ALONG THE MEANDERING
SURFACE BOUNDARY. EXPECT WIDESPREAD RAINFALL ACCUMULATIONS
AROUND 1 INCH OVERNIGHT...WITH LOCALIZED 4 INCH AMOUNTS
POSSIBLE WHERE ANY TRAINING HEAVY RAINS FOCUS ON THE SURFACE
BOUNDARY.

* BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS. IF FLASH FLOODING IS
OBSERVED...ACT QUICKLY. MOVE UP TO ESCAPE FLOOD WATERS. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY. VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED
QUICKLY. IF YOUR VEHICLE STALLS...ABANDON IT AND SEEK HIGHER
GROUND IMMEDIATELY. RAPIDLY RISING WATER MAY ENGULF YOUR VEHICLE
AND ITS OCCUPANTS AND SWEEP THEM AWAY. MOVE TO HIGHER GROUND.

THIS WATCH WILL LIKELY NEED TO BE EXTENDED AND OR RECONFIGURED
ON FRIDAY AS ADDITIONAL RAINFALL IS LIKELY.

$$

[ticka1]

NWS has issued a Flash Flood Watch until 700pm this evening.

Discussion:

Water vapor images clearly shows upper low stalled out over SW TX with good feed of moisture off the Gulf over the middle and upper TX coast. Surface reflection/vort lobe currently moving northward through Waller County was responsible for the morning heavy rainfall. Amounts averaged 2-3 inches over SE Harris Co. near the Bay and 1-2 inches over the NW part of the county. The heaviest rainfall has remained offshore this morning where convergent low level flow is noted.

Air mass has likely been worked over by morning convection and will take a few hours to recover. Lift associated with N moving meso low will weaken with time. Should see some clearing to the SW of the area shortly pushing temps. toward the trigger temps. and likely starting the whole convective process over again. Have noted that storm motions S and SW of metro Houston have really slowed in the past few hours and this is of some concern…as the fast storms motions this morning and yesterday have helped reduce higher rainfall totals. Not sure how much development we will see this afternoon as dry slot on water vapor rotates in from the SW…we shall see.

Saturday:

Similar pattern in place tomorrow as today with 2.2-2.4 inch PWS and strongly divergent upper air pattern. Slug of moisture off the LA coast may push more west on Saturday as upper high begins to build in from the east. Will once again have to go with 70-80% coverage on Saturday.

Rain chances should begin to come down starting Sunday as ridging attempts to build in from the east allowing modest drying. Will still be plenty of moisture for daily afternoon storms, but coverage should be reduced.

Historical Note:

July has been an extremely wet month across the state following a record wet June. Below are the current rainfall amounts for selected cities and their normal July rainfall. The Victoria and Corpus amounts are incredible.

Victoria: 18.71 inches (2.50 normal)
Corpus Christi: 18.05 inches (1.66 normal)
IAH: 9.13 inches (2.70 normal) 7th wettest July on record
Galveston: 7.51 inches (2.90 normal)
San Antonio: 11.06 inches (1.67 normal)

A look back at history does reveal a surprising fact. The top 5 wettest July’s at IAH were in the following years:

1. 1900
2. 1942
3. 1943
4. 1961
5. 1955

Interestingly tropical cyclones impacted the TX in 4 out of the 5 above years after a very wet July.

<LI class=MsoNormal style="mso-list: l0 level1 lfo1">1900 --- Great Galveston Hurricane (cat 4) <LI class=MsoNormal style="mso-list: l0 level1 lfo1">1942 --- Galveston (cat 1), Matagorda Bay (cat 1) <LI class=MsoNormal style="mso-list: l0 level1 lfo1">1943 --- Galveston (cat 2) <LI class=MsoNormal style="mso-list: l0 level1 lfo1">1961 --- Hurricane Carla, Matagorda Bay (cat 4)
1995 --- None
IAH is .25 of an inch away from becoming the 6th wettest July on record and 5.67 inches away from the wettest July on record.

[Texas SpeedDiva]

Ticka,

thanks for posting the historical info on the wet July's corresponding to hurricanes. I've had a couple of people here at the office ask me about that because they had heard something somewhere.

[BaytownWeatherWatcher]

a bit off topic, but I was wondering if anyone knows what the winters were like following record rains in previous summers like we're having this summer. (Hoping for a really cold winter this year!)

[longtalltexan79]

I'm all for history NOT repeating itself in this instance... :eek3:

As for the rain we haven't gotten any up here in Livingston...maybe one downpour, but for the most part this has been a nonevent for us...and we need the rain cause everything is dry here...I'm going to have to go out in a little bit and water everything...

[Texas SpeedDiva]

You are joking? You are having to go out and water? Please let me send you some of the water from my flooded yard which has been in either small lake or swamp condition for the past month.

Good news they just cancelled the Flash Flood Watch for Galveston Co.

[longtalltexan79]

You are joking? You are having to go out and water? Please let me send you some of the water from my flooded yard which has been in either small lake or swamp condition for the past month.



Nope I kid you not...we haven't gotten but one short downpour out of all of this...the bed up at the front near the mailboxes is VERY dry the plants are wilting....I'd gladly take some of the water from you! I hate going out to water cause the mosquitos are on the warpath!