MAY 2020

[unome]

tornado warning dropped but severe t'storm warning continues - green clouds, looked nasty north of us

https://twitter.com/iembot_hgx
https://twitter.com/NWSHouston
https://www.weather.gov/hgx/



BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Houston/Galveston TX
457 PM CDT Sun May 24 2020

The National Weather Service in League City has issued a

* Severe Thunderstorm Warning for...
Northwestern Austin County in southeastern Texas...
Southeastern Washington County in southeastern Texas...
Northwestern Waller County in southeastern Texas...

* Until 530 PM CDT.

* At 457 PM CDT, a severe thunderstorm was located near Bellville,
moving northeast at 20 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...
Brenham, Hempstead and Bellville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 2985 9629 2991 9649 3022 9639 3012 9606
TIME...MOT...LOC 2157Z 203DEG 15KT 2994 9636

HAIL...1.00IN
WIND...60MPH

$$
TJC

[don]

Looks like the MCS is slowly moving south towards the I-10 corridor.

[davidiowx]

I was thinking the same thing. Seems like storms may be turning towards the south (or reforming in that direction anyways). I noticed the NAM was showing this this morning. It basically showed some convection going in every different direction lol

[unome]

check out "rotation" option, choose auto update & loop - can change loop criteria

https://mrms.nssl.noaa.gov/qvs/product_viewer/

[unome]

Flood Advisory
National Weather Service Houston/Galveston TX
515 PM CDT Sun May 24 2020

TXC201-339-473-242315-
/O.NEW.KHGX.FA.Y.0034.200524T2215Z-200524T2315Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Harris TX-Montgomery TX-Waller TX-
515 PM CDT Sun May 24 2020

The National Weather Service in League City has issued a

* Flood Advisory for...
Harris County in southeastern Texas...
Southwestern Montgomery County in southeastern Texas...
Northeastern Waller County in southeastern Texas...

* Until 615 PM CDT.

* At 515 PM CDT, Doppler radar indicated heavy rain due to
thunderstorms. Minor flooding is ongoing or expected to begin
shortly in the advisory area. Between 1 and 3 inches of rain have
fallen.

Some locations that will experience flooding include...
Southern Conroe, Tomball, Pinehurst, The Woodlands, Spring,
Hockley, Oak Ridge North, Shenandoah, Magnolia, Stagecoach, Hooks
Airport, Cypress, Willowbrook, The Woodlands Pavillion, Splashtown
and Chateau Woods.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Advisory means river or stream flows are elevated, or
ponding of water in urban or other areas is occurring or is imminent.

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

[DoctorMu]

Major outflow boundary from the MCS heading toward Jason and Houston.

[dp6]

Just curious, why is the Houston NWS office the only one in the region that hasn't issued a Hazardous Weather Outlook? Every other office in Texas except El Paso had one out this morning. As did most of LA, AR, MO, all of OK, and extending further north. This seems to happen a lot. Any reason why the Houston office likes to be the exception?

[Cpv17]

Meanwhile down here in Wharton County we’re frying in the pan. Thank goodness there’s a decent breeze blowing.

[unome]

rotation east of Woodlands ?

https://mrms.nssl.noaa.gov/qvs/product_viewer/

[unome]

https://twitter.com/NWSWPC/status/1264689328308940800

Mesoscale Precipitation Discussion 0245
NWS Weather Prediction Center College Park MD
646 PM EDT Sun May 24 2020

Areas affected...South-central Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 242245Z - 250400Z

SUMMARY...Thunderstorms with very heavy rainfall are expected to
increase in coverage and intensity this evening across portions of
south-central Texas. Flash flooding will be possible for those
areas that experience training convection or cell mergers, with
rainfall rates exceeding two inches per hour at times.

DISCUSSION...An increasingly favorable atmospheric environment for
thunderstorms with very heavy rain will exist across portions of
south central Texas through the remainder of the evening hours.
Discrete thunderstorm clusters have developed over the Rio Grande
Valley and are slowly progressing eastward, and a well-developed
outflow boundary is moving towards the southwest from the MCS that
developed over eastern Texas this afternoon. In combination with
an approaching mid-level vortmax from the west, low level boundary
interactions in a very unstable airmass with 3000 to 4000 J/kg of
MLCAPE should provide enough lift to generate additional
thunderstorms over the next several hours.

Another area of more immediate concern will be the nearly
stationary band of storms that have developed along the southern
portion of the outflow boundary across southeast Texas. A steady
flow of deep moisture from the Gulf of Mexico, advecting nearly 2
inch PWs northward over that boundary, is fueling this convection.
These cells are producing rainfall rates on the order of 1.5 to
2.5 inches per hour, perhaps locally higher, and a flash flood
threat continues to exist here.

In terms of the high resolution guidance, there has been a
consistent signal in the past few runs of the HRRR and the
experimental HRRR for patchy areas of 2 to 4 inch rainfall totals
through 11 pm local time. It appears that the guidance is
underdone with the convection that currently exists northwest of
Houston based on current radar trends.

Hamrick

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...CRP...EWX...FWD...HGX...LCH...SJT...

ATTN...RFC...WGRFC...NWC...

[unome]

Flood Advisory
National Weather Service Houston/Galveston TX
556 PM CDT Sun May 24 2020

TXC201-339-250100-
/O.NEW.KHGX.FA.Y.0036.200524T2256Z-200525T0100Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Harris TX-Montgomery TX-
556 PM CDT Sun May 24 2020

The National Weather Service in League City has issued a

* Urban and Small Stream Flood Advisory for...
Harris County in southeastern Texas...
Southeastern Montgomery County in southeastern Texas...

* Until 800 PM CDT.

* At 556 PM CDT, Doppler radar indicated heavy rain due to slow
moving thunderstorms. Rainfall rates in excess of 2 inches per
hour are possible. This will cause urban and small stream flooding.

Some locations that will experience flooding include...
Humble, Spring, Kingwood, Greater Greenspoint, Aldine, The
Woodlands, northern Northside / Northline, Oak Ridge North,
Shenandoah, Patton Village, Roman Forest, Woodbranch, Woodloch,
Porter Heights, Bush Intercontinental Airport, Splashtown, Chateau
Woods, Atascocita, Lake Houston and East Little York / Homestead.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Advisory means river or stream flows are elevated, or
ponding of water in urban or other areas is occurring or is imminent.

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

[unome]

Flood Advisory
National Weather Service Houston/Galveston TX
603 PM CDT Sun May 24 2020

TXC201-291-339-250100-
/O.NEW.KHGX.FA.Y.0037.200524T2303Z-200525T0100Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Harris TX-Liberty TX-Montgomery TX-
603 PM CDT Sun May 24 2020

The National Weather Service in League City has issued a

* Urban and Small Stream Flood Advisory for...
Harris County in southeastern Texas...
Northwestern Liberty County in southeastern Texas...
East Central Montgomery County in southeastern Texas...

* Until 800 PM CDT.

* At 603 PM CDT, Doppler radar indicated heavy rain due to slow
moving thunderstorms. Merging cells will cause rain rates in
excess of 2 inches per hour. This will cause urban and small
stream flooding.

Some locations that will experience flooding include...
Cleveland, Splendora, Patton Village, Roman Forest, Woodbranch,
Plum Grove, Tarkington Prairie, Romayor, Moss Hill and Rye.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Advisory means river or stream flows are elevated, or
ponding of water in urban or other areas is occurring or is imminent.

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

[jasons2k]

1.70" and counting...

We were out and about just before it hit. Some of the darkest skies I've seen. The rain drops at times, just before the bottom dropped-out, were HUGE. It was like water balloons hitting the windshield.

[unome]

Flood Advisory
National Weather Service Houston/Galveston TX
712 PM CDT Sun May 24 2020

TXC071-201-291-250215-
/O.NEW.KHGX.FA.Y.0039.200525T0012Z-200525T0215Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chambers TX-Harris TX-Liberty TX-
712 PM CDT Sun May 24 2020

The National Weather Service in League City has issued a

* Urban and Small Stream Flood Advisory for...
Northern Chambers County in southeastern Texas...
Harris County in southeastern Texas...
Liberty County in southeastern Texas...

* Until 915 PM CDT.

* At 712 PM CDT, Doppler radar and automated rain gauges indicated
heavy rain due to thunderstorms. This will cause urban and small
stream flooding. Between 1 and 2 inches of rain have fallen.

Some locations that will experience flooding include...
Northern Baytown, Liberty, Dayton, Mont Belvieu, Old
River-Winfree, Ames, Daisetta, Hardin, Kenefick, Cove, Devers,
Dayton Lakes, Lake Houston, Wallisville and Hankamer.

Localized rainfall rates of upwards of 2 inches per hour are
possible over the area. This additional rain will result in minor
flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flood Advisory means river or stream flows are elevated, or
ponding of water in urban or other areas is occurring or is imminent.

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

[Belmer]

Something you don't see too often: a severe thunderstorm warning that made me think it was a watch at first. Also inside that large warning are three tornado warned storms within it. Meanwhile Austin has been under the same severe thunderstorm warning for over an hour now. That is also something you don't see often.

Needless too say, models did horribly with the convection around SETX today. Though as a result, atmosphere will likely be much more worked over and I don't feel very confident the storms out near San Antonio will make it here into SETX overnight before collapsing Though, this is a very difficult setup to forecast (as we saw today), so certainly don't let your guard down.


Edit to add: I should clarify that I don't believe the intensity of the storms out west will be what they are when they reach the viewing area, but rain and embedded thunderstorms could still be likely.

Screen Shot 2020-05-24 at 8.10.57 PM.png

[Cromagnum]

We are out south of Abilene and had a pretty monster system blow through. I see the one down near Austin looks much stronger.

[unome]

https://spacecityweather.com/one-round- ... to-follow/

[unome]

yikes https://rammb-slider.cira.colostate.edu ... 181&y=1225

[jasons2k]

I have my doubts that the northern side of the MCS moving-in from Central Texas will hold together north of the outflow from today's earlier storms over SE Texas, but we will see. There is a short window of recovery, but time is running out quickly.

[DoctorMu]

I have my doubts that the northern side of the MCS moving-in from Central Texas will hold together north of the outflow from today's earlier storms over SE Texas, but we will see. There is a short window of recovery, but time is running out quickly.

This run of GFS and CMC are more optimistic about the Hill Country MCS partly holding together overnight and drifting east.