April 2016 Recap: Regional Flood/Severe Weather

[unome]

Fort Polk, LA & Central TX radars both down
http://wdssii.nssl.noaa.gov/web/wdss2/p ... 2vcp.shtml

[djjordan]

The timing certainly isn't good for those Radars to go down that's for sure.

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LAKE CHARLES LA
517 AM CDT WED APR 27 2016

THE NATIONAL WEATHER SERVICE IN LAKE CHARLES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
TYLER COUNTY IN SOUTHEASTERN TEXAS...
NORTHWESTERN JEFFERSON COUNTY IN SOUTHEASTERN TEXAS...
HARDIN COUNTY IN SOUTHEASTERN TEXAS...
WESTERN JASPER COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 615 AM CDT

* AT 516 AM CDT...SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM 8 MILES EAST OF GROVETON TO NEAR GOODRICH TO 8 MILES
EAST OF CLEVELAND TO NEAR PLUM GROVE TO BRAYS OAKS...MOVING EAST AT
50 MPH.

HAZARD...60 MPH WIND GUSTS AND PENNY SIZE HAIL.

SOURCE...RADAR INDICATED.

IMPACT...EXPECT DAMAGE TO ROOFS...SIDING...AND TREES.

* LOCATIONS IMPACTED INCLUDE...
BEAUMONT...LUMBERTON...SILSBEE...WOODVILLE...KOUNTZE...SOUR LAKE...
COLMESNEIL...NOME...CHESTER...THICKET...FRED...SARATOGA...EBENEZER...
ROCKLAND...TOWN BLUFF...WARREN...WILDWOOD...BEVIL OAKS...CHINA AND
LAKEVIEW.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

INTENSE THUNDERSTORM LINES CAN PRODUCE BRIEF TORNADOES AND WIDESPREAD
SIGNIFICANT WIND DAMAGE. ALTHOUGH A TORNADO IS NOT IMMEDIATELY
LIKELY...IT IS BEST TO MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF A BUILDING. THESE STORMS MAY CAUSE SERIOUS INJURY AND SIGNIFICANT
PROPERTY DAMAGE.

LARGE HAIL AND DAMAGING WINDS AND CONTINUOUS CLOUD TO GROUND
LIGHTNING IS OCCURRING WITH THESE STORMS. MOVE INDOORS IMMEDIATELY.
LIGHTNING IS ONE OF NATURES LEADING KILLERS. REMEMBER...IF YOU CAN
HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.

[unome]

lightning loop http://atmo.tamu.edu/ciams/lma/network_loop.html

power outages

CenterPoint http://gis.centerpointenergy.com/outagetracker/

Entergy http://www.etrviewoutage.com/external/tx.aspx

Oncor http://gis.centerpointenergy.com/outagetracker/

[djjordan]

118,000 plus are without power according to Centerpoint.

Numerous Trees and Live wires down in Montgomery County

Willis ISD is closed today

Numerous trees reported down near Tomball

Reports of numerous trees and power lines down as well as residential damage from Magnolia to Montgomery to Willis.

Montgomery ISD is delayed 2 Hours this morning

Livingston ISD is delayed 2 Hours this morning

Crosby ISD is delayed 2 Hours this morning

Shephard ISD is delayed 2 Hours this morning

[unome]

busy morning for HGX https://weather.im/iembot/

they corrected the Livingston report, no windows blown out

[unome]

from HGX significant weather advisory: http://mesonet.agron.iastate.edu/wx/afo ... 1604271033

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
OFFICE IN LEAGUE CITY.

[unome]

bot currently posting GOES-14 infrared

https://twitter.com/SRSORbot

[djjordan]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
551 AM CDT WED APR 27 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHEASTERN LIBERTY COUNTY IN SOUTHEASTERN TEXAS...
NORTHEASTERN GALVESTON COUNTY IN SOUTHEASTERN TEXAS...
CHAMBERS COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 645 AM CDT

* AT 550 AM CDT...SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM NEAR DAISETTA TO 6 MILES NORTHEAST OF SAN LEON...
MOVING EAST AT 45 MPH.

HAZARD...60 MPH WIND GUSTS.

SOURCE...RADAR INDICATED.

IMPACT...EXPECT DAMAGE TO ROOFS...SIDING...AND TREES.

* LOCATIONS IMPACTED INCLUDE...
TEXAS CITY...EASTERN LIBERTY...BEACH CITY...SOUTHEASTERN MONT BELVIEU...
ANAHUAC...OLD RIVER-WINFREE...AMES...DAISETTA...HARDIN...COVE...DEVERS...
HIGH ISLAND...BOLIVAR PENINSULA...WINNIE...CRYSTAL BEACH...SAN LEON...
STOWELL...GILCHRIST...ROLLOVER PASS AND SMITH POINT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

[djjordan]

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
554 AM CDT WED APR 27 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHEASTERN LIBERTY COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 615 AM CDT

* AT 554 AM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO
WAS LOCATED NEAR DEVERS...OR 8 MILES WEST OF NOME...MOVING EAST AT 45
MPH.

HAZARD...TORNADO.

SOURCE...RADAR INDICATED ROTATION.

IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT
SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED.
DAMAGE TO ROOFS...WINDOWS...AND VEHICLES WILL OCCUR. TREE
DAMAGE IS LIKELY.

* LOCATIONS IMPACTED INCLUDE...
DAISETTA AND DEVERS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST
FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF YOU ARE OUTDOORS...IN A
MOBILE HOME...OR IN A VEHICLE...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER
AND PROTECT YOURSELF FROM FLYING DEBRIS.

[djjordan]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
608 AM CDT WED APR 27 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHWESTERN GALVESTON COUNTY IN SOUTHEASTERN TEXAS...
SOUTHEASTERN BRAZORIA COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 645 AM CDT

* AT 608 AM CDT...SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM NEAR PORT BOLIVAR TO 6 MILES WEST OF SAN LUIS PASS...
MOVING SOUTHEAST AT 40 MPH.

HAZARD...60 MPH WIND GUSTS.

SOURCE...RADAR INDICATED.

IMPACT...EXPECT DAMAGE TO ROOFS...SIDING...AND TREES.

* LOCATIONS IMPACTED INCLUDE...
GALVESTON ISLAND WEST END...GALVESTON CAUSEWAY...TEXAS CITY...LA
MARQUE...HITCHCOCK...SURFSIDE BEACH...GALVESTON PIER 21...BAYOU VISTA...
JAMAICA BEACH...TIKI ISLAND...GALVESTON PLEASURE PIER...PELICAN
ISLAND...SCHLITTERBAHN...GALVESTON STATE PARK...THE STRAND...SAN LUIS
PASS...SCHOLES FIELD...MOODY GARDENS...PORT BOLIVAR AND OFFATTS BAYOU.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

[djjordan]

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOUSTON...LIBERTY...
SOUTHEASTERN WALKER...SAN JACINTO...EASTERN MONTGOMERY...POLK...
NORTHEASTERN HARRIS AND TRINITY COUNTIES UNTIL 715 AM CDT...

AT 610 AM CDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM 11 MILES NORTHWEST OF ROCKLAND TO NEAR OLD
RIVER-WINFREE. MOVEMENT WAS EAST AT 50 MPH.

WINDS IN THE WAKE OF THESE STORMS ACROSS THE AREA WILL GUST IN
EXCESS OF 40 MPH WILL BE POSSIBLE WITH THESE STORMS. GIVEN THE WET
GROUNDS ACROSS THE AREA THESE STRONG WINDS MAY BLOW OVER TREES.

LOCATIONS IMPACTED INCLUDE...
EASTERN CONROE...HUMBLE...LIBERTY...CLEVELAND...DAYTON...LIVINGSTON...
SPRING...KINGWOOD...APPLE SPRINGS...THE WOODLANDS...OAK RIDGE NORTH...
SHEPHERD...SHENANDOAH...ONALASKA...SPLENDORA...CORRIGAN...PATTON VILLAGE...
ROMAN FOREST...WOODBRANCH AND CUT AND SHOOT.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 AM CDT FOR
SOUTHEASTERN TEXAS.

[srainhoutx]

Unfortunately with our saturated ground, the bow echo was just too much for many trees across the Region. The Storm Prediction Center is expecting a somewhat similar situation Friday into Saturday. Thanks for the updates during the night gang. Folks were following the progress of the Storms while they were rolling across Central Texas headed out way.

[unome]

very sad: https://nwschat.weather.gov/lsr/#AMA,BR ... 80459/1111

Time: 2016-04-27 09:49 UTC
Event: 0 TSTM WND DMG
Source: broadcast media
Remark: *** 1 fatal *** a downed tree onto a mobile home killed an elderly female in tomball.

[srainhoutx]

Wednesday morning briefing from Jeff:

Clearly the capping inversion eroded over SE TX this morning likely helped from lift from an incoming short wave. The end result was a line of damaging thunderstorms with widespread strong winds of 50-65mph from Grimes and northern Waller Counties into Montgomery and N Harris Counties. A 65mph wind gust was recorded at Navasota and 59 at Conroe. Corridor of wind damage is likely fairly extensive along the Harris/Montgomery County lines where bow echo moved ESE down the county line. Additional KIAH terminal radar showed a very well defined notch along the line near Kuykendahl Rd just SSW of Spring Creek which may have produced a tornado. Reports of windows blown out of homes in parts of Montgomery County and Polk County on tornado warned cell that passed from Willis toward Lake Livingston.

Late Week:

Yet another powerful upper level system will move into the SW US by Thursday and begin to spread lift and disturbances across TX on Friday. Low level moisture will begin to return in earnest tonight and continue into Saturday with PWS rising to near 1.8-2.0 inches. Upper air flow becomes increasingly divergent Friday into Saturday and when working on an unstable air mass expect numerous thunderstorms especially on Saturday. Think some degree of capping may help keep thunderstorms more scattered on Friday…if at all. Will need to take a look at the severe threat as the time gets closer…could be some severe weather on Saturday.

Concern really goes up Saturday as a slow moving boundary (trough or weak front), strong low level inflow, and good lift all point toward a heavy rainfall event across E/NE TX. Potential certainly looks to exist for cell training of excessive rainfall on Saturday. Still too early to be certain on rainfall amounts, but widespread amounts of 1-3 inches look possible.

Hydro:

Area is not in a good situation to handle a significant rainfall event as being shown for late this week. River have just begun recessions from the previous rainfall and continued rounds of rainfall are maintain a saturated ground profile. Flood control lakes have begun to move water through their systems and water supply lakes continue to evacuate water levels above their normal pool.

Simply stated there is just not much room in the river systems for additional rainfall.

Widespread nature of the upcoming event Friday-Saturday is deeply concerning as this will put a lot of pressure on area rivers and lake that are already very high. With grounds saturated expect much of what falls is going to run-off with significant rises on are watersheds…so back to above flood stage.

[unome]

Galveston District, U.S. Army Corps of Engineers updates

• https://www.facebook.com/GalvestonDistrict/
  
  https://twitter.com/usacegalveston
  
  https://www.dvidshub.net/image/2553060/ ... arker-dams

[srainhoutx]

Quick update to follow up on Jeff's briefing regarding Friday/Saturday and why there is more concern for the heavy rainfall potential during that timeframe:

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
522 AM EDT WED APR 27 2016


FINAL DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID APR 27/1200 UTC THRU APR 30/1200 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAYS 2/3...

...NEXT UPPER LOW MOVING FROM THE SOUTHWEST INTO THE
ROCKIES/PLAINS...

ANOTHER UPPER LOW WILL FORM OVER THE SOUTHWESTERN PORTION OF THE
COUNTRY ON THURSDAY...SLOWLY EJECTING EAST INTO THE ROCKIES AND
PLAINS FRIDAY/SATURDAY. THE SYNOPTIC EVOLUTION OF THIS SYSTEM IS
FORECAST TO BE REMARKABLY SIMILAR TO THE SYSTEM CURRENTLY
IMPACTING THE PLAINS. ON THE LARGE SCALE THE GUIDANCE IS IN
RELATIVELY GOOD AGREEMENT WITH THIS SYSTEM. THE 0Z NAM IS PROBABLY
THE BIGGEST OUTLIER ALOFT...AND GIVEN ITS USUAL POOR QPF
PERFORMANCE ANYWAYS...STAYED AWAY FROM ITS QPF OUTPUT. THE 0Z
GFS/ECMWF ARE MOST SIMILAR WITH THE UPPER LOW LATITUDE
PROGRESSION...WITH THE UKMET A BIT NORTH AND THE GEM SOUTH.
HOWEVER THE GFS IS A BIT SLOWER THAN THE ECMWF/UKMET/GEM. NO
STRONG SIGNAL SEEN IN THE ENSEMBLES OR RECENT TRENDS TO
NECESSARILY FAVOR ONE SOLUTION OVER ANOTHER...SO OPTED TO GO WITH
A SOLUTION IN THE MIDDLE OF THE SPREAD. THIS MIDDLE GROUND
SOLUTION IS PROBABLY BEST REPRESENTED BY THE 0Z ECMWF...ALTHOUGH
COMPONENTS OF THE QPF FROM THE GFS/ECMWF/GEM/UKMET WERE ALL USED
IN MANUALLY DERIVING A MIDDLE GROUND SOLUTION.

THE BIGGEST HEAVY PRECIPITATION THREAT BEGINS TO EVOLVE BY
THURSDAY NIGHT INTO FRIDAY AS THE SYSTEM EJECTS EAST. TWO AREAS OF
CONCERN FOR HIGHER QPF AMOUNTS. ONE IS ACROSS PORTIONS OF NE/KS
AND EASTERN CO. THIS AREA WILL SEE MAXIMUM SYNOPTIC ASCENT AHEAD
OF THE APPROACHING VORT MAX AND IN A DIVERGENT PATTERN ALOFT.
EXPECT MID/UPPER LEVEL SOUTHERLY FLOW TO ADVECT ANOMALOUS MOISTURE
UP AND OVER THE LOWER LEVEL COLDER AIR...RESULTING IN A WIDESPREAD
SWATH OF PRECIPITATION STREAMING SOUTH TO NORTH..EVENTUALLY
WRAPPING TO THE NORTHWEST AROUND THE LOW. INSTABILITY IS WEAK TO
NON EXISTENT IN THIS PART OF THE SYSTEM...THUS RATES SHOULD BE
LOWER. HOWEVER COULD INITIALLY SEE SOME CONVECTIVE ELEMENTS AND
LOCALLY HIGHER RATES ACROSS WESTERN KS AND FAR SOUTHERN NE ON
FRIDAY. ALTHOUGH IN GENERAL THINK RATES SHOULD REMAIN LOW ENOUGH
TO PREVENT AN ORGANIZED FLASH FLOOD RISK ACROSS THIS AREA.

THE OTHER REGION OF CONCERN IS ACROSS EASTERN TEXAS...SOUTHEAST
OKLAHOMA...WESTERN ARKANSAS AND NORTHWEST LOUISIANA. NOTE SOME
DIFFERENCES COMPARED TO THE CURRENT SYSTEM ACROSS THIS REGION.
FIRST OFF SHOULD HAVE A MORE WELL DEFINED WEST TO EAST BOUNDARY
SETUP ACROSS TEXAS. APPEARS THAT THE COLD FRONT THAT PROGRESSES
THROUGH THE AREA TODAY WASHES OUT NEAR THE GULF COAST...AND
EVENTUALLY IS THE BOUNDARY THAT RETURNS AS A WARM FRONT AS THE
NEXT TROUGH APPROACHES THURSDAY/FRIDAY. THIS BOUNDARY SHOULD BE
ABLE TO ACT AS A FOCUS FOR CONVECTIVE DEVELOPMENT AND
ORGANIZATION. ALSO NOTE THAT THE SUBTROPICAL JET IS FORECAST TO BE
MORE OPTIMALLY LOCATED FOR ENHANCING UPPER LEVEL DIVERGENCE. THE
MOISTURE PLUME ADVECTING NORTH IS ALSO FORECAST TO BE MORE
IMPRESSIVE...WITH PRECIPITABLE WATER ANOMALIES 1-2 STANDARD
DEVIATIONS ABOVE NORMAL ACROSS THIS REGION. THUS THE INGREDIENTS
APPEAR TO COME IN PLACE FOR A HEAVY RAINFALL AND FLOOD THREAT.
THINK THE GFS IS PROBABLY A BIT QUICK WITH CONVECTIVE INITIATION
ON THURSDAY AS IT APPEARS TO RETURN MOISTURE/INSTABILITY QUICKER
OWING TO A WEAKER FRONTAL PUSH INTO THE GULF. GIVEN THE CURRENT
CONVECTIVE STATE AS OF THIS MORNING THINK THE STRONGER ECMWF
FRONTAL PUSH IS MORE LIKELY.

EITHER WAY WILL EVENTUALLY GET CONVECTIVE DEVELOPMENT THURSDAY
NIGHT ALONG THE STALLED EAST WEST FRONT AS THE LOW LEVEL JET
INCREASES. STORM MOTION SHOULD BE OFF TO THE NORTHEAST...HOWEVER
AS THE LOW LEVEL JET INCREASES AND CONVECTION BECOMES MORE
ORGANIZED...CORFIDI VECTORS SUGGEST EAST/WEST TRAINING ALONG THE
BOUNDARY IS POSSIBLE...WITH SOME BACKBUILDING TO THE SOUTH
PLAUSIBLE AS WELL. BY LATER FRIDAY SHOULD ALSO SEE CONVECTIVE
DEVELOPMENT EITHER ALONG THE DRY LINE IN WEST TX OR THE COLD FRONT
ALOFT FURTHER EAST IN TEXAS...WITH THIS CONVECTION FORMING A LINE
AND PROGRESSING SOUTHEAST TOWARDS THE GULF COAST. NOT SURPRISING
THEN THAT MODELS SUGGEST AMOUNTS OF 3-5" ARE POSSIBLE SOMEWHERE
ACROSS EAST TX/SOUTHEAST OK/SOUTHWEST AR AND/OR NORTHWEST LA. AS
USUAL WITH ANY CONVECTIVE SITUATION THE EXACT LOCATION OF HIGHEST
AMOUNTS REMAIN UNCERTAIN. WPC QPF TRIED TO FIND A CONSENSUS
POSITION OF THE LAST COUPLE RUNS OF THE GFS/ECMWF ALONG WITH THE
GEM/UKMET. WILL GO AHEAD AND ISSUE A SLIGHT RISK OF EXCESSIVE
RAINFALL FOR THIS AREA. GIVEN THE FAVORABLE MOISTURE PARAMETERS
AND THE POTENTIAL OF TRAINING...COULD EVENTUALLY NEED AN UPGRADE
TO A MODERATE RISK IF/WHEN CONFIDENCE INCREASES ON THE MOST LIKELY
IMPACTED AREAS.

[srainhoutx]

There is still some uncertainty regarding our sensible weather tomorrow and Saturday, so will wait until this afternoon to see some additional data. That said the SPC has outline a Slight Risk for severe thunderstorms for tomorrow across Texas and with a slow moving boundary draped somewhere across Central Texas into Saturday, there is some potential for training storms but the lack of consistency between the various guidance schemes make if rather difficult to pin down where the heaviest rainfall may occur outside of the areas outline by the Weather Prediction Center Excessive Rainfall Outlook for Day 2. None of the reliable guidance is indicating anything near the magnitude of the heavy rainfall event we experienced a week ago last Monday.

[srainhoutx]

Thursday morning briefing from Jeff:

***Heavy Rainfall and Severe Thunderstorms Friday night-Sunday***

Discussion:
Repeating upper level pattern in place will bring yet another storm system across TX this weekend. Large upper level system currently digging into the SW US will transition upper level winds to the SW aloft starting midday on Friday allowing upper level disturbances to translate across the area by Friday afternoon. Surface warm front will back inland this afternoon allowing a very moist Gulf air mass to spread northward. PWS will be on the rise back toward near record levels for this time of year…something that has become almost normal of late. As the upper level low moves into the NM region, upper level winds over SE/E TX will go increasingly divergent helping to add lift to the air mass. A surface front will slowly drop southward over TX adding more lift and helping to focus convection.

Rainfall:
Ingredients are coming together to produce a widespread rainfall event with some excessive rainfall looking likely over parts of the area. Overall favorable set up of strong low level inflow, high moisture levels, slowing/training storm motions, and a defined low level boundary at point toward an excessive rainfall and flash flood threat. Main question remains as to where the greatest totals might be found. Orientation of the expected line of convection early Saturday appears to favor areas north of I-10, but I have seen time and time again where outflow boundaries push storms further southward than expected. Meso scale influences will dictate this event and will determine where the greatest rainfall will be.

Will of with widespread amounts of 1-3 inches over the area with isolated totals of 4-5 inches. Could see even higher amounts especially under any sustained training areas.

Severe:
Air mass will become unstable on Friday and a few isolated severe thunderstorms may develop with a large hail or damaging wind threat. Severe threat increases Friday night into Saturday as complex of storms approaches from the W/NW. Think the main threats will be wind damage and large hail, but would not rule out a weak isolated tornado similar to yesterday morning (see below). SPC has a large portion of SE TX outlooked for Friday afternoon into Friday night and a portion of this risk area may need to be upgraded to a higher risk.

Given the extremely wet grounds…even non-severe thunderstorm winds may uproot and knock over trees.

Hydro:

Region remains highly sensitive to additional rainfall. Widespread nature of this upcoming event will put additional pressure on river systems still draining flood flows from a couple of weeks ago and the complexes of storms every 2-3 days we have experienced since then.

Will likely see new rises on area rivers given the expected rainfall and some that have recently fallen below flood stage may return to at or above flood levels.

Recent Rainfall:

As wet as 2015 was….2016 is starting out even wetter!

Since March 1, 2016…. Houston, Columbus, Sugarland, and Houston Westbury have all recorded their wettest March 1-April 27 period on record. Columbus has surpassed their 2015 record by over 2.0 inches. The City of Houston has surpassed its 2015 same period record by an astounding by 4.59 inches.

Tomball…Klein Tornado:
NWS survey team investigated the wind damage across northern Harris County yesterday and determined a weak tornado occurred 6 miles SW of The Woodlands along Willow Creek in the Willow Forest Subdivision. The tornado was .41 miles wide with a damage path of 40 yards and winds estimated near 70mph. Numerous large pines were snapped or uprooted with several trees impacted homes. 1 person was killed when a tree fell on their mobile home.

[jasons2k]

I mentioned this in a thread several months ago...but the number of these 1 in 1,000 years, 1 in 500 years, or in some cases 1 in 10,000 years events keep becoming the 'norm', at what point do you redefine what 'normal' is? I believe the NWS uses a 20-year running average to calculate "normals" - but what about extremes?

When these extreme events are no longer extreme, then what's the line between 'normal' and 'extreme'? When you get multiple 500-year floods within the span of a couple of decades, how can we keep calling it a 500-year event? It almost seems like the data points we are using is behind the reality of the situation. Thoughts?

[Cromagnum]

Just take a look at Houston and the surrounding suburb sprawl that has happened over the last 50 years. Heck, even 20 or so years ago there was not very much to look at in Sugarland or Pearland, let alone other areas. More concrete = less places to drain. I don't think it has rained any harder lately than historically to account for this.