April 2016 Recap: Regional Flood/Severe Weather

[jasons2k]

Clearing is accelerating in satellite - things are getting charged-up.

[djmike]

Im thinking nothing drastic today. Was told we should see another system roll through overnight or early morning. That didnt happen. Even now (almost noon) Im not seeing anything really organized headed our way. Might be diff later as we heat up but as for now. Thought this event was supposed to last until Thursday.

[mcheer23]

I'm thinking the radar trend will change...

[brooksgarner]

Hey guys... we're in continuous flood coverage until at least 1pm on KHOU 11 News. I'm tracking a possibility of isolated 5" NEW amounts -- and a few models, as you've seen -- are suggesting already hard hit areas getting more rain... Also, any of these isolated amounts fall upstream from these flooded areas, it could re-initiate flooding.

Thank you for all of your posts regarding this event!

[davidiowx]

Im thinking nothing drastic today. Was told we should see another system roll through overnight or early morning. That didnt happen. Even now (almost noon) Im not seeing anything really organized headed our way. Might be diff later as we heat up but as for now. Thought this event was supposed to last until Thursday.

It looked like it was trying to happen last night but the first system stabilized the atmosphere so the one last night couldn't get going. I had a little bit of rain at my house around 10 last night. Nothing even remotely close to heavy rain though.

Looks like the Low over Colorado is weakening and moving out. If I were a betting man, I would say we are done for the widespread heavy rains.

[brooksgarner]

Not to distract from task at hand, but in the long-range forecast, anyone seeing this NEXT big upper low diving down, farther south than the current one-- per the EURO, for late next week?

[srainhoutx]

Definitely need to.watch the next system diving SE from the Gulf of Alaska early next week. Brooks, some of us were commenting on the potential upper pattern to reload while at the National Tropical Weather Conference last week.

In the immediate forecast potential, keeping an eye on the streamers developing in SW Brazoria County. The boundary has moved N of NW Harris County so the potential is there for storm development across the area.

[unome]

Hey guys... we're in continuous flood coverage until at least 1pm on KHOU 11 News. I'm tracking a possibility of isolated 5" NEW amounts -- and a few models, as you've seen -- are suggesting already hard hit areas getting more rain... Also, any of these isolated amounts fall upstream from these flooded areas, it could re-initiate flooding.

Thank you for all of your posts regarding this event!

Thank you Brooks, for your expert, professional coverage on tv & social media, as well as on here - excellence. Loved hearing the insight on how you & David Paul develop your forecasts !

[Ounce]

Hey guys... we're in continuous flood coverage until at least 1pm on KHOU 11 News. I'm tracking a possibility of isolated 5" NEW amounts -- and a few models, as you've seen -- are suggesting already hard hit areas getting more rain... Also, any of these isolated amounts fall upstream from these flooded areas, it could re-initiate flooding.

Thank you for all of your posts regarding this event!

Thank you Brooks, for your expert, professional coverage on tv & social media, as well as on here - excellence. Loved hearing the insight on how you & David Paul develop your forecasts !

+1
Yeah, you did really well. I especially liked it when you got your geek on and started explaining why rain cells naturally want to head north.

[Stormrider]

Kudos to KHOU for its extended coverage, especially the weather team. Kudos also to the Board members and our Moderators and Experts.

I got a 1/2 inch on the east end of Galveston. I know officially it was closer to 2 inches. I feel for everyone in Houston dealing with the ongoing flooding.

[brooksgarner]

Hi Guys!

Good eye on the boundary setting up right now, for our near-term. I'm sorry I missed the National Tropical Weather Conference but sounds like good info.

Standby... more continuous coverage on TV and Facebook at http://fb.com/khouBrooksGarner

It's all moving downstream.........

[Ounce]

Cells are starting to pop. I-10 East inside the Loop. South of South Belt. 288 south of 6.

[srainhoutx]

Getting a bit concerned for locations along the stalled boundary from Waller, NW Harris, Montgomery and San Jacinto Counties. Sunshine is destabilizing the atmosphere with daytime heating and little movement is noted on towering cumulus clouds building. These areas have been hit particularly hard since Sunday evening and additional rainfall will only exasperate ongoing flooding along Cypress Creek down to the Addicks Reservoir.

[unome]

http://www.wpc.ncep.noaa.gov/discussion ... isc=pmdspd

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
241 PM EDT Tue Apr 19 2016

Valid 00Z Wed Apr 20 2016 - 00Z Fri Apr 22 2016

...Flash flooding possible for portions of the southern plains and western
Gulf Coast states...

...Well above average temperatures expected for the northwestern U.S...

An upper-level low and nearly stationary frontal boundary across the
central U.S. will finally begin to move slowly eastward on Wednesday. In
the meantime, showers and thunderstorms will continue for much of the
southern/central plains and portions of the western Gulf Coast through
tonight. Locally heavy rain will be possible, which may result in flash
flooding for some areas. Farther west, snow showers will continue tonight
for the higher elevations of the Rockies as energy associated with the
upper-level low remains overhead. On Wednesday, the system will spread
showers and thunderstorms into portions of the Upper Midwest and Great
Lakes, as well as portions of the Ohio and Tennessee valleys. Locally
heavy rainfall will remain possible on Thursday for portions of the lower
and middle Mississippi valleys. By Thursday, the system will continue its
slow movement eastward, and will spread showers and thunderstorms across
the lower Great Lakes and into portions of the Northeast, as well as the
Southeast.

Across the West Coast, conditions will remain generally dry. Scattered
showers and thunderstorms are possible across portions of the Pacific
Northwest this afternoon/evening and again Wednesday. High pressure at the
mid and upper-levels of the atmosphere will help to keep coverage of
precipitation scattered, and will also keep high temperatures 10 to 25
degrees above average on Wednesday and Thursday. More widespread showers
are forecast to begin spreading into the coastal Northwest by late
Thursday as a Pacific frontal boundary approaches.


Ryan

Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php

[Andrew]

Getting a bit concerned for locations along the stalled boundary from Waller, NW Harris, Montgomery and San Jacinto Counties. Sunshine is destabilizing the atmosphere with daytime heating and little movement is noted on towering cumulus clouds building. These areas have been hit particularly hard since Sunday evening and additional rainfall will only exasperate ongoing flooding along Cypress Creek down to the Addicks Reservoir.

Yea me too, I think convection will remain scattered but steering has broken down. Not much movement in the cells that pop up.

[houstonia]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
218 PM CDT TUE APR 19 2016

TXC201-192015-
/O.NEW.KHGX.FA.Y.0020.160419T1918Z-160419T2015Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HARRIS TX-
218 PM CDT TUE APR 19 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* FLOOD ADVISORY FOR...
SOUTH CENTRAL HARRIS COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 315 PM CDT

* AT 216 PM CDT...DOPPLER RADAR A SLOW MOVING CLUSTER OF STORMS
PRODUCING RAINFALL RATES UP TO NEAR 2 INCHES PER HOUR. THIS RAIN
MAY QUICKLY RUNOFF TO CAUSE ADDITIONAL STREET FLOODING IN THE
ADVISORY AREA.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
NORTHWESTERN PASADENA...SOUTH HOUSTON...BELLAIRE...WEST UNIVERSITY
PLACE...GALENA PARK...JACINTO CITY...ASTRODOME AREA...GREATER FIFTH
WARD...FOURTH WARD...NEARTOWN / MONTROSE...SECOND WARD...GREATER
EASTWOOD...DOWNTOWN HOUSTON...GREENWAY / UPPER KIRBY AREA...UNIVERSITY
PLACE...GREATER THIRD WARD...MIDTOWN HOUSTON...MACGREGOR...GREATER
HOBBY AREA AND AFTON OAKS / RIVER OAKS AREA.

LAT...LON 2983 9529 2969 9517 2959 9536 2970 9551

$$

[srainhoutx]

Update from Jeff:

Urban Flood Advisory for SE Harris County until 315pm

Heating combined with returning Gulf moisture and a weak surface trough is resulting in the formation of strong thunderstorms over SE Harris County. Thunderstorms are showing very slow cell motions toward the SW with weak steering. Rainfall rates of 1-2 inches will be possible under these storms leading to street flooding.

The area currently being impacted was not overly hard hit yesterday and can handle this kind of rainfall. Will need to watch trends very closely over the next few hours in case storms try to develop WNW/NW into the northern portions of the county that were hit very hard yesterday.

[unome]

tops are really popping down there http://www.ssec.wisc.edu/data/1min/

[houstonia]

Pouring down rain in Meyerland right now.

[unome]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
314 PM CDT TUE APR 19 2016

.DISCUSSION...
THE THREAT OF LOCALLY HEAVY RAINFALL WILL CONTINUE THROUGH
WEDNESDAY...AND WILL EXTEND THE FLASH FLOOD WATCH TO 7 PM
WEDNESDAY EVENING.

IN THE SHORT TERM...A TROPICAL MOISTURE TAP FROM THE PACIFIC
CONTINUED STREAMING OVERHEAD A WEAK NORTH-TO-SOUTH SURFACE
BOUNDARY THAT WAS LOCATED NEAR THE INTERSTATE 45 CORRIDOR AT 2 PM
/SURFACE DEWPOINTS TO THE EAST OF THE BOUNDARY WERE IN THE LOWER
70S...WITH MID 60S TO THE WEST/. IN ADDITION...A WEAK UPPER LEVEL
SHORTWAVE WAS HELPING TO GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS. MOST OF THE DEVELOPMENT HAS BEEN TO THE EAST OF
THE SURFACE BOUNDARY THIS AFTERNOON. THE HIGH RESOLUTION MODELS
FORECAST THE ACTIVITY TO DIMINISH LATER TODAY BETWEEN MID EVENING
AND MIDNIGHT.

A MODEL CONSENSUS FORECASTS AN AREA OF THUNDERSTORMS TO MOVE
INTO THE NORTHWESTERN SET OF COUNTIES BEGINNING AROUND SUNRISE ON
WEDNESDAY MORNING AND THEN OVERSPREADING THE AREA DURING THE DAY.
MODEL QPF FOR THIS EVENING THROUGH WEDNESDAY EVENING WAS BETWEEN 1
AND 2 INCHES. MODEL PW/S REACH FROM 1.5 TO 1.6 INCHES ON
WEDNESDAY...SO THINK THAT LOCALIZED RAINFALL TOTALS OF 2 TO 4
INCHES WILL BE POSSIBLE.

THE UPPER LOW OVER THE PLAINS LOOKS TO FINALLY SHEAR OUT AND MOVE
EAST INTO THE OHIO VALLEY ON THURSDAY AND THURSDAY NIGHT. AS IT
DOES SO...ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE OVER SE TX AHEAD OF A FRONTAL BOUNDARY THAT SHOULD WORK
ITS WAY TO THE COAST THURSDAY NIGHT. A DRYING TREND IS EXPECTED
FOR FRIDAY AND SATURDAY. ANOTHER UPPER LEVEL SYSTEM WILL THEN MOVE
INTO THE PLAINS ON SUNDAY AND BRING AT LEAST SLIGHT CHANCES FOR
RAIN FOR THE FIRST OF NEXT WEEK.

40

&&

.MARINE...
LIGHT TO MODERATE ONSHORE WINDS ALONG WITH PERIODS OF SHOWERS AND
THUNDERSTORMS WILL PERSIST UNTIL THURSDAY NIGHT WHEN A COLD FRONT
MOVES THROUGH THE AREA. SEAS ARE RUNNING 3 TO 5 FEET MAINLY DUE TO
SWELLS. EXPECT SEAS TO GRADUALLY SUBSIDE TONIGHT AND TOMORROW. THE
LIGHT TO MODERATE OFFSHORE WINDS BEHIND THE FRONT WILL PERSIST
THROUGH EARLY SATURDAY. 33

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 68 78 67 79 60 / 40 70 30 60 30
HOUSTON (IAH) 67 78 67 81 64 / 30 70 40 70 30
GALVESTON (GLS) 71 77 70 79 68 / 30 50 50 60 30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH THROUGH WEDNESDAY EVENING FOR THE FOLLOWING
ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
LIBERTY...MONTGOMERY...POLK...SAN JACINTO...WALKER...
WALLER...WASHINGTON...WHARTON.

GM...NONE.
&&

$$

DISCUSSION...40
AVIATION/MARINE...33