April 2016 Recap: Regional Flood/Severe Weather

[djjordan]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
141 AM CDT WED APR 13 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
EAST CENTRAL WHARTON COUNTY IN SOUTHEASTERN TEXAS...
HARRIS COUNTY IN SOUTHEASTERN TEXAS...
NORTHWESTERN GALVESTON COUNTY IN SOUTHEASTERN TEXAS...
NORTHERN BRAZORIA COUNTY IN SOUTHEASTERN TEXAS...
EASTERN FORT BEND COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 230 AM CDT

* AT 141 AM CDT...SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM SPRING BRANCH CENTRAL TO FAIRCHILDS TO NEAR
NEEDVILLE TO NEAR BOLING-IAGO...MOVING EAST AT 45 MPH.

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

SOURCE...RADAR INDICATED.

IMPACT...HAIL DAMAGE TO VEHICLES IS EXPECTED. EXPECT WIND DAMAGE
TO ROOFS...SIDING...AND TREES.

* LOCATIONS IMPACTED INCLUDE...
PASADENA...PEARLAND...LEAGUE CITY...SUGAR LAND...BAYTOWN...MISSOURI
CITY...TEXAS CITY...FRIENDSWOOD...LA PORTE...DEER PARK...SOUTHEASTERN
ROSENBERG...ALVIN...ANGLETON...DICKINSON...STAFFORD...SOUTH HOUSTON...
BELLAIRE...WEST UNIVERSITY PLACE...LA MARQUE AND SANTA FE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

[djjordan]

Heavy rain and small hail at my house ..... surprisingly very little wind.

[djjordan]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
147 AM CDT WED APR 13 2016

TXZ226-236-237-130730-
MATAGORDA TX-BRAZORIA TX-WHARTON TX-
147 AM CDT WED APR 13 2016

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN WHARTON...NORTHERN
MATAGORDA AND SOUTHWESTERN BRAZORIA COUNTIES UNTIL 230 AM CDT...

AT 147 AM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 8
MILES NORTHWEST OF MARKHAM...OR 11 MILES SOUTHEAST OF EL CAMPO...MOVING
EAST AT 40 MPH.

DIME SIZE HAIL AND WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
BAY CITY...WEST COLUMBIA...SWEENY...BRAZORIA...VAN VLECK...MARKHAM...WILD
PEACH VILLAGE AND DANEVANG.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 500 AM CDT FOR
SOUTHEASTERN TEXAS.

[djjordan]

Now is not such a good time to be on the water anyways....... Small craft seek safe harbor.


BULLETIN - IMMEDIATE BROADCAST REQUESTED
SPECIAL MARINE WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
153 AM CDT WED APR 13 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SPECIAL MARINE WARNING FOR...
COASTAL WATERS FROM FREEPORT TO MATAGORDA SHIP CHANNEL TX OUT 20
NM...
COASTAL WATERS FROM HIGH ISLAND TO FREEPORT TX OUT 20 NM...
MATAGORDA BAY...

* UNTIL 345 AM CDT

* AT 151 AM CDT...STRONG THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM ROUGHLY LIBERTY TO HOUSTON TO EDNA...MOVING
SOUTHEAST AT 30 KNOTS. ADDITIONAL CELLS WERE MOVING IN FROM THE
SOUTH AND WILL COLLIDE WITH THE INCOMING LINE CAUSING FURTHER
INTENSIFICATION.

HAZARD...WIND GUSTS 34 KNOTS OR GREATER AND SMALL HAIL.

SOURCE...RADAR INDICATED.

IMPACT...SMALL CRAFT COULD BE DAMAGED IN BRIEFLY HIGHER WINDS AND
SUDDENLY HIGHER WAVES.

* LOCATIONS IMPACTED INCLUDE...
GALVESTON 256...BUOY 42035...MATAGORDA JETTY...BRAZOS 490...GALVESTON
317...GALVESTON 344...BRAZOS 400...HIGH ISLAND 63...TABS BUOY B...
MATAGORDA SHIP CHANNEL...BRAZOS 439...GALVESTON 150...HIGH ISLAND 157...
GALVESTON 221...TABS BUOY W...HIGH ISLAND A179...HIGH ISLAND 208...
MATAGORDA ISLAND 557...GALVESTON 282 AND SURFSIDE JETTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT LIGHTNING IS OCCURRING WITH THESE STORMS. IF CAUGHT ON THE
OPEN WATER STAY BELOW DECK IF POSSIBLE...KEEP AWAY FROM UNGROUNDED
METAL OBJECTS.

[DoctorMu]

Heavy rain and small hail at my house ..... surprisingly very little wind.

There may be an outflow boundary ahead of the storm.

[djjordan]

Heavy rain and small hail at my house ..... surprisingly very little wind.

There may be an outflow boundary ahead of the storm.

That's what I was thinking as it looked like just before the bow echo made it to my house there was some convergence happening ahead of it. Not complaining though ... really didn't want to lose power and glad we got some rain .... lawn was starting to look a bit thirsty.

[djjordan]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
216 AM CDT WED APR 13 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

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

* UNTIL 245 AM CDT

* AT 215 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED OVER VAN VLECK...OR
NEAR BAY CITY...MOVING EAST AT 35 MPH.

HAZARD...QUARTER SIZE HAIL.

SOURCE...RADAR INDICATED.

IMPACT...DAMAGE TO VEHICLES IS EXPECTED.

* LOCATIONS IMPACTED INCLUDE...
WESTERN LAKE JACKSON...BAY CITY...WEST COLUMBIA...SWEENY...BRAZORIA...
JONES CREEK...VAN VLECK...MARKHAM AND WILD PEACH VILLAGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

[djjordan]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
227 AM CDT WED APR 13 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHEASTERN LIBERTY COUNTY IN SOUTHEASTERN TEXAS...
GALVESTON COUNTY IN SOUTHEASTERN TEXAS...
CHAMBERS COUNTY IN SOUTHEASTERN TEXAS...
EAST CENTRAL MATAGORDA COUNTY IN SOUTHEASTERN TEXAS...
SOUTHEASTERN BRAZORIA COUNTY IN SOUTHEASTERN TEXAS...
SOUTHEASTERN HARRIS COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 330 AM CDT

* AT 224 AM CDT...SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM OLD RIVER-WINFREE TO LEAGUE CITY TO NEAR DANBURY TO
NEAR BAY CITY...MOVING SOUTHEAST AT 40 MPH.

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

SOURCE...RADAR INDICATED.

IMPACT...HAIL DAMAGE TO VEHICLES IS EXPECTED. EXPECT WIND DAMAGE
TO ROOFS...SIDING...AND TREES.

* LOCATIONS IMPACTED INCLUDE...
EASTERN PASADENA...EASTERN LEAGUE CITY...SOUTHEASTERN BAYTOWN...
GALVESTON CAUSEWAY...GALVESTON ISLAND WEST END...TEXAS CITY...LAKE
JACKSON...ALVIN...ANGLETON...DICKINSON...LA MARQUE...SANTA FE...FREEPORT...
SEABROOK...CLUTE...HITCHCOCK...BEACH CITY...KEMAH...SURFSIDE BEACH AND
GALVESTON PIER 21.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

[Katdaddy]

The early morning squall line that brought the small hail, gusty winds, and very heavy rain has pushed off the Middle and Upper TX Coast. A few additional thunderstorms will move along the coastal areas this morning. Nice weather Thursday and Friday before additional rain chances begin to increase Saturday afternoon. Onward to the 2016 National Tropical Weather Conference this morning.

[ticka1]

Email from Jeff Lindner - Wednesday morning:

Impressive line of thunderstorms crossed the area overnight with several large hail reports.

Overnight activity has progressed into the coastal waters of LA while the surface boundary has remained anchored near the coast. Trailing short wave energy continues to provide lift over the top of this boundary resulting in a W to E band of thunderstorms extending from south of Edna to Galveston Island. This line has shown very little motion to the north or south while it sits and trains from W to E . Rainfall totals are averaging 1-2 inches with these storms per hour and will have to watch totals in this area over the next few hours as flash flooding may quickly develop.

Thus far there is no radar indication of this activity attempting to lift northward toward the more populated areas of the US 59 corridor, but will need to keep an eye on any trends this morning on the meso scale. Could easily see 2-4 inches of rainfall in the next 2-3 hours over southern Jackson, Matagorda, Brazoria, and Galveston Counties.

Should see overall activity weaken and shift eastward by late morning with possibly some breaks in the overcast. Position of the upper level system over the southern plains will keep weak dynamics aloft in play this afternoon and could see additional showers and thunderstorms develop with a little heating. Will favor those coastal/near coastal counties for best chances of any afternoon development.

Thursday-Friday:
Ridging and a drier air mass behind the cool front will reside over the region. May have a hard time getting rid of the cloud cover on Thursday with better chances for breaks in the clouds on Friday. Moisture advection begins to return to the region late on Friday.

Weekend/Early Next Week:
A large upper level storm system currently over the Gulf of Alaska will move into the SW US and slow down as it runs up against strong high pressure over the eastern US. Still much uncertainty on where the main moist axis will set up this weekend as this location will feature a good chance of thunderstorms with heavy rainfall and flooding. Latest guidance has trended slightly westward with the position of the upper level low with the moist feed aimed across SC TX into NW TX which keeps SE TX on the eastern fringe of the highest rain chances and largest QPF. Potential remains for some big rains at some point in the Saturday-Tuesday period…leaning more toward Monday at the moment. Severe weather will also be possible especially with any thunderstorm complexes that move out of C or NW TX.

Overnight Storm Reports:

Weimar, Colorado: Tree limbs down and damage to roofs from fast moving bow echo.

Needville, Fort Bend: Quarter size hail

Needville, Fort Bend: 1.25 in hail.

Richmond, Fort Bend: dime size hail at FM 2977 and FM 762

Rosenberg, Fort Bend: dime size hail at US 59 and FM 2218

Katy, Fort Bend: nickel size hail in Cinco Ranch

Friendswood, Galveston: 1.0 in size hail

Webster, Harris: 1.0 in size hail

Galveston, Galveston: 47mph wind gust reported 8SE Galveston Is

Matagorda, Matagorda: 40mph wind gust recorded by hurricaneflow site

Galveston, Galveston: N jetty sustained at 47 g 52mph.

Surfside, Brazoria: 43mph gust at hurricanflow site

Bacliff, Galveston: 38mph at hurricaneflow site

[jojotheidiotclown]

Anyone have a long range outlook for temperatures? Looking forward to the heat and sunshine.

[MontgomeryCoWx]

Its been hot.

However, Summer was canceled and we are going to skip straight to our first strong cold front of the 2016 calendar year.

[jojotheidiotclown]

lol, this isn't hot. this is jacket weather.

If summer is canceled. I want to meet the folks who did that. I got to learn their secret, so I can cancel winter.

[sleetstorm]

I wonder what the residents in and around the city of San Antonio received from last night's austere thunderstorm complex. Is there any way to know only out of curiosity? And those who live in cities Seguin to Katy?

[jeff]

Pattern setup this weekend into early next week is getting concerning with respect to heavy rainfall and flash flooding. 00Z GFS crushes the area with rainfall late Sunday-early Tuesday showing 9.23 inches at IAH. I would not believe this amount nor this run...but the overall consensus is big rains are coming to TX.

[unome]

I guess I'll get some outdoor stuff done in the next few days while I can !

http://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml

http://www.wpc.ncep.noaa.gov/para/#page=qpf

6-hourly loop, days 1-7 http://www.wpc.ncep.noaa.gov/qpf/qpfloop_6hr_d17.html

[ticka1]

Email from Jeff Lindner Thursday morning:

Major storm system to bring widespread impacts to TX this weekend into early next week.

Excessive rainfall becoming increasingly likely with potential flash flooding and river flooding.

Discussion:
Powerful upper level storm system currently off the NW US coast will drop SSE and into the SW US over the next 48 hours. High pressure over the eastern US will result in the slowing down of this Pacific storm system over the SW US this weekend. Favorable low level wind trajectories off the western Caribbean Sea and southern Gulf of Mexico will pump extremely high moisture levels into TX starting late Friday and peaking late Saturday into Monday. Large upper level system over the SW US will only slowly creep eastward this weekend into early next week as it runs up against the high pressure ridge along the US east coast. Waves of energy will rotate around the stalled parent low over NM sweeping across TX and interacting with the highly moisture air mass to produce many rounds of thunderstorms from Saturday (out west) to much of the state Sunday-Tuesday.

Think most of Saturday will feature breezy southerly winds under cloudy skies and a few passing S to N moving showers under a capping inversion (warm air a few thousand feet above the ground). Forecast models are coming into some agreement on a fairly strong short wave rotating out of the upper trough and across TX Saturday afternoon. This looks like the initial event across SW into the I-35 corridor Saturday evening into the overnight. Starting to be concerned about a slow moving training line of excessive rainfall cross that I-35 corridor “flash flood alley” Saturday night into Sunday. Model QPF is showing some healthy totals in this region during that time period which could lead to rapid flash flooding.

Expect this line/band of weather to move into SE TX on Sunday and move very slowly across the region. A few models really pound the area Sunday afternoon and all night into Monday morning with repeated thunderstorms producing excessive rainfall. GFS is showing a surface trough feature developing inland over SE TX Sunday into Monday with strong low level inflow off the Gulf and PWS at or over 1.9 inches (99th percentile for mid April). The ingredients are screaming flash flood set up…but the exact location of where the heaviest rains will set up is impossible to determine at this point.

Impacts:
WPC QPF products from Saturday-Tuesday is very concerning with widespread high amounts being shown across much of NC, C, and SE TX. Almost positive the placement will move around some over the next few days as is usual with such events, but someone is going to get a lot of rainfall during this time period given the atmospheric set up. It is still too early to get into specific totals, but think widespread 2-4 inches is a good bet with much higher isolated totals. 00Z GFS has 9.23 inches for KIAH Sunday into Monday…don’t think this will happen at IAH, but it shows the potential for such totals somewhere across the region.

Hydro:
We are not in the best hydro situation to accommodate such a widespread rainfall event. Rivers, flood control, and water supply lakes are still moving water from the early March flooding east of I-35 and grounds east of I-35 are generally saturated from the recent rainfall yesterday morning. The widespread and prolonged nature of this event is going to put a lot of pressure on area rivers and expect significant rises on almost all watersheds should the current QPF verify over the state. Some rivers would almost certainly go into flood with this magnitude of rainfall. I am particularly concerned with the Brazos and Navasota basins as models have been somewhat consist on high QPF over these basins, but think all basins are in play.

Severe Weather:
Think the overall severe threat will be highest Saturday west of I-35 where the best instability will be located. Air mass eastward becoming increasing saturate with warm rain processes which tend to not support as much severe weather. Cannot rule out a large hail or damaging wind gust with any storms (it is mid April), but think the overall severe threat will be lower compared to the heavy rainfall and flash flood threat.

5-Day QPF Totals (Today-Tuesday):

don't know how to bring the map over from email....

[Andrew]

EURO also has 17 inches just south of Houston but I suspect it had some convective parameterization issues. I think 2-4 inches widespread is a good bet right now. Still see greatest forcing to the northwest but that could easily change as we move into the weekend.

[mcheer23]

Andrew can you post a map
With the euro rainfall?

[Andrew]

Andrew can you post a map
With the euro rainfall?

The ECMWF hi-res maps are behind paywalls but basically a 17inch isolated spot appears just south of Harris County. Mainly from one or two storms. Chances of it actually happening that way are very slim.