September. Heavy Rainfall Event/Flooding Possible 9/28-30th

[ticka1]

great weekend to stay indoors and watch movies and relax!!!!! praying we get lots of rain and cooler weather!

[wxman57]

great weekend to stay indoors and watch movies and relax!!!!! praying we get lots of rain and cooler weather!

My idea of relaxing is a 4-5 hour bike ride. Guess I'll be going to a movie on Saturday. Better mow the lawn when I get home today. Don't really need any more rain this year. Y'all can have it up north.

[MontgomeryCoWx]

Kind of pissed this is going to rain on our A&M Tailgate and Game plans, but I'll just pack an extra flask for gametime!!

[wxman57]

Kind of pissed this is going to rain on our A&M Tailgate and Game plans, but I'll just pack an extra flask for gametime!!

I made a meteogram for College Station for a co-worker who is heading up for the game. Not a pretty weather day on Saturday. Looks like the rain starts late Friday evening and lasts until just before sunrise on Sunday. Heaviest rain Saturday afternoon (12pm-7pm). Model indicates about 1.5 to 2” total rain during the event. Note that the temperatures on Saturday may be falling into the 60s during the afternoon (cool and wet).

[texoz]

What are the chances that 94E off the western coast of Mexico tosses some moisture over to Texas next week?

[Karen]

What are the chances of rain down south. We have not gotten much lately.

[Belmer]

Been raining here in San Marcos for about two hours. Started around 8:15 and poured in buckets for about an hour straight. Then the last hour was a more moderate rain. Haven't checked rain gauges yet, but my guess would be somewhere a little over an inch.

Thought about you, Portastorm ...didn't look like Austin got much of this. Hope everyone gets a little (or lot) somethin this weekend.

Be safe!

[srainhoutx]

Worrisome to see the guidance every 6-12 hours for the past 4-5 days peg some areas of Central/SE TX with 2-8 inch rainfall totals. Last night it appears the areas near El Campo picked up 4 inches of rain with training cells. The GFS/CMC and now the HIRES NAM are 'sniffing' some very impressive rainfall totals across the Southern half of Texas. I see Flood Watches are up for the Big Country and frankly wouldn't be surprised to see additional regions added to those Watches later today. Friday night into Saturday could be very interesting for many folks. It may be time to stay tuned as developments could change rather quickly over the next 24-36 hours...

[srainhoutx]

The San Antonio/Austin areas just hoisted a Flood Watch as well.

[unome]

no watering this weekend

[srainhoutx]

Houston/Galveston NWS suggesting Flood Watches will be issued later today for Friday night into Sunday. The 06Z GFS came in suggesting a slower moving surface low along the Texas Coast moving NE with heavy rainfall across much of SE TX and not exiting the area until during the day on Sunday. Areas along and S of I-10 appear to be the favored areas, but the 06Z GFS was suggestive areas N of the I-10 Corridor may not escape the heavy rainfall. A combination of EPAC Tropical moisture from Miriam and 94E do raise an eyebrow and a slow moving Coastal Low as well as favorable upper level flow from the WSW combined with a slowly advancing frontal boundary is typically the ingredients that bring heavy rainfall events to Texas. Stay Tuned!

[srainhoutx]

Morning e-mail from Jeff:

Widespread heavy rainfall becoming increasingly likely.

Parameters continue to come together from midday Friday-Sunday to produce widespread heavy rainfall across the region. Slow moving upper level trough over the SW US will begin to spread large scale lift into TX over the next 6-12 hours with surface low pressure forming over the SW Rio Grande plains near/around Laredo. Tremendous tropical moisture advection off the western Gulf of Mexico will surge PWS into the 2.0-2.4 in range by late today with mid and high level moisture arriving from the west from the remains of EPAC hurricane Miriam. Surface low will move ENE across the area on Saturday/early Sunday with widespread thunderstorms.

Flash Flood Threat:
With the air column becoming increasingly saturated over the next 12 hours rainfall production will become more tropical like with excessive short term rainfall rates likely. Moisture levels rise to near 2 standard deviations above late September averages and this combined with the potential for cell training and organized slow moving storms really raises the threat for flash flooding. While grounds are fairly dry and flash flood guidance is high, short term rainfall rates of 2-4 inches per hour will be possible given the setup and air mass capabilities and the threat for training or slowing storm motions could extend such a rainfall rate over a period of time. Urban areas will be at greatest risk from the short term excessive rainfall rates likely leading to street flooding and ponding. While most rivers are at base flow or below total rainfall amounts over the weekend will likely produce significant rises.

Widespread amounts of 2-4 inches appear likely with isolated totals of 3-6 inches and I would not at all be surprises to see some locations with totals in the 8-10 inch range (these bigger totals) should be fairly isolated. Similar set ups in the past (October 1998) and (October 2002) have produce some incredible short term rainfall amounts especially over SC TX. Still too early to attempt to determine where the greatest risk area will be, but areas along and south of I-10 will have the best moisture.

A Flash Flood Watch will likely be require for portions or all of SE TX later today.

[unome]

a bit off topic, but has anyone been able to get into the weather survey on HGX's home page? http://www.srh.noaa.gov/hgx/

I've tried IE & Firefox, no luck - this is the link that's there right now http://%20svy.cfigroup.com/launch/NWS/

***********************************
Edit - found a good link elsewhere: http://svy.cfigroup.com/launch/NWS/

[Portastorm]

Houston/Galveston NWS suggesting Flood Watches will be issued later today for Friday night into Sunday. The 06Z GFS came in suggesting a slower moving surface low along the Texas Coast moving NE with heavy rainfall across much of SE TX and not exiting the area until during the day on Sunday. Areas along and S of I-10 appear to be the favored areas, but the 06Z GFS was suggestive areas N of the I-10 Corridor may not escape the heavy rainfall. A combination of EPAC Tropical moisture from Miriam and 94E do raise an eyebrow and a slow moving Coastal Low as well as favorable upper level flow from the WSW combined with a slowly advancing frontal boundary are typically the ingredients that bring heavy rainfall events to Texas. Stay Tuned!

A Flash Flood Watch is in effect for nearly all of south central Texas through Saturday evening. In their morning forecast discussion, NWSFO EWX said the heavy rain threat per the latest computer models is being delayed into Saturday ... which I assume means it's a bit delayed for SE Texas as well. What is concerning is mention of "historic maxima" in terms of precipitable water values (PWATs), meaning the atmosphere is totally juiced up for a LOT of rain.

[srainhoutx]

Houston/Galveston NWS suggesting Flood Watches will be issued later today for Friday night into Sunday. The 06Z GFS came in suggesting a slower moving surface low along the Texas Coast moving NE with heavy rainfall across much of SE TX and not exiting the area until during the day on Sunday. Areas along and S of I-10 appear to be the favored areas, but the 06Z GFS was suggestive areas N of the I-10 Corridor may not escape the heavy rainfall. A combination of EPAC Tropical moisture from Miriam and 94E do raise an eyebrow and a slow moving Coastal Low as well as favorable upper level flow from the WSW combined with a slowly advancing frontal boundary are typically the ingredients that bring heavy rainfall events to Texas. Stay Tuned!

A Flash Flood Watch is in effect for nearly all of south central Texas through Saturday evening. In their morning forecast discussion, NWSFO EWX said the heavy rain threat per the latest computer models is being delayed into Saturday ... which I assume means it's a bit delayed for SE Texas as well. What is concerning is mention of "historic maxima" in terms of precipitable water values (PWATs), meaning the atmosphere is totally juiced up for a LOT of rain.

Another fly in the ointment is the potent short wave depicted on the 00Z Euro to dive SE into NE TX/AR on Sunday. I also see that the SPC is mentioning storm chances have been extended for Sunday in Central and all of Coastal Texas. Another factor that will need to be watched carefully is just how deep the Coastal Low becomes as it slowly moves NE toward Louisiana on Sunday. Gusty winds with very heavy rainfall rates in this environment certainly may not be out of the question.

[srainhoutx]

From Nesdis:

SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 09/28/12 1326Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-683-1404
LATEST DATA USED: GOES-14 1315Z HANNA
.
LOCATION...TEXAS...
.
ATTN WFOS...EWX...SJT...LUB...MAF...
ATTN RFCS...WGRFC...
.
EVENT...HEAVY RAIN
.
SATELLITE ANALYSIS AND TRENDS...LATEST SURFACE ANALYSIS SHOWS WEAK
SYNOPTIC FRONTAL BOUNDARY EXTENDING FROM NEAR THE ARKLATEX AND EXTENDING
SW TOWARDS THE BIG BEND AREA. RETURN FLOW OF MOISTURE AHEAD OF TROFFING
OVER THE E PAC HAS BEEN RAPIDLY INCREASING THIS MORNING OVER THE LOWER
RIO GRANDE VALLEY ACCORDING TO LATEST BLENDED PW ANALYSIS. THIS RETURN
FLOW HAS BEEN OVERRUNNING SYNOPTIC BOUNDARY AND HAS RESULTED IN A SMALL
QUASI-STATIONARY MCS TYPE FEATURE THAT EXTENDS FROM ANDREWS AND ECTOR
COUNTY E TO FISHER AND NOLAN COUNTY. THE MOST ACTIVE AREA OF CONVECTION
AND PERIODIC CLOUD TOP COOLING WITHIN THIS AREA APPEARS TO HAVE MOVED OVER
MITCHELL COUNTY AND ALSO MOST RECENTLY OVER MARTIN COUNTY. BELIEVE THAT
RAINFALL RATES WITHIN THIS AREA ARE LIKELY RUNNING OVER 1.0"/HR.
.
SHORT TERM OUTLOOK VALID 1240-1540Z...MEDIUM CONFIDENCE FACTOR IN SHORT
TERM OUTLOOK...IT APPEARS AS THOUGH LOCAL AREA VWPS HAVE SHOWN SOME
MODEST WEAKENING AND BACKING OF LLJ OVER THE LAST HOUR. BELIEVE THAT THE
WEAKENING OF LLJ SHOULD ONLY BE TEMPORARY THOUGH AS UPSTREAM SHORTWAVE
TROF OVER N MEXICO SHOULD ALLOW FOR A CONTINUED BACKING AND EVENTUAL
STRENGTHENING OF LLJ. SO BELIEVE THAT ALTHOUGH THERE MAY BE AN EVENTUAL
TEMPORARY WEAKENING OF ONGOING SYSTEM THAT FOCUS WILL SHIFT FURTHER W
INTO W CNTRL AND SW TX. FOR THE MEANTIME THOUGH, WOULD EXPECT ADDITIONAL
RAINFALL TOTALS OF 1.0-2.0" FROM MITCHELL COUNTY AND THEN SLOWLY SPREADING
ENE INTO POSSIBLY PORTIONS OF NOLAN AND TAYLOR COUNTY.

[wxman57]

Euro and GFS in good agreement now in a slower eastward movement of the frontal wave/low. Peak rainfall in SE TX Saturday evening through sunrise Sunday, through it will probably be raining hear from Saturday morning to late Sunday morning. General rainfall amounts 1.5 to 3 inches across Houston. Some areas could see 4-6 inches (north of the track of the low). This type of rain is typically widespread light to moderate rain with a few embedded thunderstorms rather than quick bursts of 2-3 inches of rain that we see in summertime storms.

[srainhoutx]

There were some subtle differences between the 12Z NAM and the HIRES NAM, but both are suggesting some impressive rainfall totals with some spots nearing the 6-8 inch + range N of where the Coastal Low tracks. HGX continues to advertise a Flood Watch is coming later today...


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1016 AM CDT FRI SEP 28 2012

...LOCALLY HEAVY RAINFALL EXPECTED ACROSS A LARGE PART OF SOUTHEAST
TEXAS OVER THE WEEKEND AS A STORM SYSTEM SLOWLY MOVES THROUGH THE AREA...

.DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS NEAR THE COAST AND OFFSHORE THIS
MORNING WILL WORK THEIR WAY INLAND TODAY. SIMILAR TO YESTERDAY AFTERNOON/
EVENING...SOME SPOTS COULD SEE SOME LOCALLY HEAVY RAINFALL IN THE SLOWER
MOVING ACTIVITY. GREATER RISK FOR HEAVY RAINFALL COMES SATURDAY THROUGH
SUNDAY MORNING WHEN A STORM SYSTEM DEVELOPS AND MOVES ACROSS OUR AREA.
VERY HIGH PRECIPITABLE WATER VALUES (>2 INCHES) COUPLED WITH DECENT
CONVERGENCE AHEAD OF A STRENGTHENING SURFACE LOW IS EXPECTED TO HELP
TO PRODUCE EVENT RAINFALL TOTALS AVERAGING 1 TO 2 INCHES WITH ISOLATED
AMOUNTS EASILY REACHING 2 TO 4 INCHES. EVEN HIGHER AMOUNTS CANNOT BE
RULED OUT! WITH AREA GROUNDS POSSIBLY BECOMING WET AHEAD OF THE MAIN
STORM SYSTEM...A FLASH FLOOD WATCH IS PROBABLY GOING TO BE ISSUED WITH
THIS AFTERNOON`S PACKAGE. EXACTLY WHERE THE HIGHEST RAINFALL TOTALS
AND GREATEST FLASH FLOOD RISK ENDS UP IS STILL HARD TO PINPOINT DUE
TO DIFFERENT MODEL SOLUTIONS CONCERNING THE LOCATION AND STRENGTH OF
THIS SYSTEM...BUT CONFIDENCE CONTINUES TO INCREASE THAT LARGE PORTIONS
OF SOUTHEAST TEXAS WILL RECEIVE HEAVY RAINFALL WITH THIS EVENT.

HERE ARE SOME AREA RECORD RAINFALL TOTALS (AND YEAR SET) FOR THIS WEEKEND.

Code: Select all

SATURDAY (9/29) SUNDAY (9/30)

CLL - 1.84" (1921)    1.85" (1927)
IAH - 2.51" (1985)    2.55" (1913)
HOU - 1.70" (1985)    1.15" (1934)
GLS - 2.12" (1921)    4.33" (1945)

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[Rip76]

Yard work and gutter cleaning happens today.

[Snowman]

what should i expect hear in New Orleans from this system?