May 2016: Shower/Storm Chances To End May

[Texaspirate11]

Still not seeing any significant pattern change as we head to the end of May. The afternoon updated Climate Prediction Center Outlook going out to the first of June suggests more unsettled weather with a continuous Western trough and rain chances.

I notice 1976, 2004, 2006, and 2007. There was flooding. I notice when El Nino is a fading away, it can be wet like 1900, 1983, and 2007.

1900? I hate when that date is mentioned.

[srainhoutx]

Looks like an active weather day ahead. Remember, #Turn Around Don't Drown...

FLOOD WATCH
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
352 AM CDT THU MAY 19 2016

AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GRIMES-HARRIS-JACKSON-LIBERTY-MATAGORDA-MONTGOMERY-
SAN JACINTO-WALKER-WALLER-WASHINGTON-WHARTON-
INCLUDING THE CITIES OF...ALVIN...ANAHUAC...ANGLETON...BAY CITY...
BELLVILLE...BRENHAM...BROOKSHIRE...BRYAN...CALDWELL...CLEVELAND...
COLDSPRING...COLLEGE STATION...COLUMBUS...CONROE...DAYTON...
EAGLE LAKE...EDNA...EL CAMPO...FREEPORT...FRIENDSWOOD...
GALVESTON...HEMPSTEAD...HOUSTON...HUMBLE...HUNTSVILLE...KATY...
LAKE JACKSON...LAKE SOMERVILLE...LEAGUE CITY...LIBERTY...
MISSOURI CITY...MONT BELVIEU...NAVASOTA...PALACIOS...PASADENA...
PEARLAND...PIERCE...PRAIRIE VIEW...RICHMOND...ROSENBERG...SEALY...
SHEPHERD...SUGAR LAND...TEXAS CITY...THE WOODLANDS...TOMBALL...
WEIMAR...WHARTON...WILLIS...WINNIE
352 AM CDT THU MAY 19 2016

...FLASH FLOOD WATCH IN EFFECT FROM 10 AM CDT THIS MORNING
THROUGH THIS EVENING...

THE NATIONAL WEATHER SERVICE IN HOUSTON/GALVESTON HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF SOUTHEAST TEXAS...INCLUDING
THE FOLLOWING COUNTIES... JACKSON...AUSTIN...BRAZORIA...
BRAZOS...BURLESON...CHAMBERS...COLORADO...FORT BEND...
GALVESTON...GRIMES...HARRIS...LIBERTY...MATAGORDA...
MONTGOMERY...SAN JACINTO...WALKER...WALLER...WASHINGTON...AND
WHARTON.

* FROM 10 AM CDT THIS MORNING THROUGH THIS EVENING

* SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP LATER THIS
MORNING AND PERSIST THROUGH THE AFTERNOON. LOCALLY HEAVY
RAINFALL IS POSSIBLE...ESPECIALLY WHERE TRAINING OF SHOWERS AND
THUNDERSTORMS OCCUR. THE RAIN AND THUNDERSTORMS ARE EXPECTED TO
DIMINISH IN COVERAGE LATER TONIGHT.

* WIDESPREAD RAINFALL AMOUNTS OF 1 TO 3 INCHES ARE EXPECTED...
WITH ISOLATED TOTALS OF 3 TO 5 INCHES POSSIBLE.

[unome]

from WPC's excessive rainfall discussion: http://www.wpc.ncep.noaa.gov/discussion ... isc=qpferd

..CENTRAL/EASTERN TX INTO SOUTHERN LA AND SOUTHERN MS...

widespread shower and thunderstorm activity with heavy rainfall amounts is expected today and tonight across a large area of central/eastern tx and into the lower ms valley as a strong area of height falls associated with an upper low ejects out of the four corners region and through the southern plains. improving upper jet dynamics and veering low level winds associated with strengthening warm air advection will foster the development and expansion of convection throughout the day that will reach the tx gulf coast this evening and then move into the lower ms valley tonight/early fri. pwats are forecast to rise to over 1.75 inches across the southeast tx coastal plain and locally approach 2 inches. this along with a pool of moderately strong instability pooled along a frontal zone attempting to lift slowly back north across the western gulf coast will help to focus very heavy rains across portions of especially southeast tx and southern la through this evening...and possibly into far southern ms by early fri. these areas are expected to see as much as 2 to 4 inches of rain...along with locally heavier amounts exceeding 5 inches given the deep moisture environment that will be in place. cannot rule out some flash flooding concerns and especially with rather wet antecedent conditions. again generally thinking that the global models are focusing their heavier qpf too far north. wpc generally favored a solution closer to some of the hires guidance in line with a consensus of the 00z wrf-arw/00z nssl-wrf and also recent runs of the hrrr/hrrrx.

Day 1

[unome]

from HGX's Hazardous Weather Outlook: http://www.srh.noaa.gov/hgx/?n=brief_support

.DAY ONE...TODAY AND TONIGHT

showers and thunderstorms are expected to become widespread later this morning and afternoon. there is a slight risk of severe thunderstorms... with the main threats large hail and damaging winds along with isolated tornadoes. locally heavy rainfall is also possible... and rainfall totals for today and tonight are expected to range from 1 to 3 inches with localized higher amounts of 3 to 5 inches possible.

[unome]

MIMIC TPW
http://tropic.ssec.wisc.edu/real-time/m ... /main.html
http://rammb.cira.colostate.edu/trainin ... ion/video/
http://tropic.ssec.wisc.edu/real-time/m ... sin=global

[srainhoutx]

Thursday morning briefing from Jeff:

Flash Flood Watch in effect from 1000am this morning until midnight.

Upper level trough is approaching SW TX this morning with radar showing numerous thunderstorms developing over SW into WC TX. A surface cool front is stalled across the coastal waters from offshore of Galveston WNW to near Del Rio. Moist southerly flow is overrunning this frontal boundary above the surface.

Trough will approach by mid morning spreading strong lift across SE TX and the frontal zone. Surface front will attempt to move northward, but not sure how much inland progress it will make with developing rainfall and thunderstorms. Boundary will act as a strong focus for additional heavy rainfall and south of the boundary a severe weather threat will be possible with mainly large hail and damaging winds.


Expect widespread and numerous thunderstorms to develop and track into the region from late morning through the afternoon hours. Air mass becomes nearly saturated by early afternoon suggesting high short duration rainfall rates in the strongest storms that could approach 3 inches per hour. Will have to very closely watch the warm frontal position as along and near this feature will be the corridor for excessive rainfall including a period of potential cell training.

Rainfall Amounts:

Widespread amounts of 1-3 inches appears likely with isolated totals of 5 inches. Some of this is going to fall in a very short period of time (an hour or less). With grounds saturated much of what falls is going to run-off and with the high short duration rainfall rates…flash flooding in urban areas…especially street will be possible this afternoon and evening.

Severe:

Think the severe threat will be held to the warm front boundary and southward. Once again…not overly confident how far this boundary will make it inland which could keep the severe threat toward the coast or even offshore. SPC has the southern 2/3rds of the area outlooked in a slight risk…think this likely extends too far northward. Will have to watch how things unfold this morning with the warm front. Could see some severe elevated storms just north of the warm front along the US 59 corridor with a large hail threat.

[unome]

NESDIS Operational Blended TPW
http://www.ospo.noaa.gov/Products/bTPW/ ... ation.html
http://www.ospo.noaa.gov/Products/bTPW/US_TPWPCT.html

[srainhoutx]

MESOSCALE PRECIPITATION DISCUSSION 0221
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
626 AM EDT THU MAY 19 2016

AREAS AFFECTED...EDWARDS PLATEAU...HILL COUNTY...AND SW TEXAS

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 191025Z - 191525Z

SUMMARY...INCREASING COVECTIVE COVERAGE AND INTENSITY WITH
POTENTIAL FOR SOME TRAINING OR SLOW MOVING CELLS MAY POSE FLASH
FLOODING THREAT.

DISCUSSION...WV LOOP SHOWS BROAD LONG WAVE TROF EJECTING IN THE
SOUTHERN PLAINS WITH MAIN CENTER IN THE OK/TX PANHANDLES BUT ALONG
THE TRAILING TROF IS ANOTHER WEAKER WAVE JUST NORTH OF THE BIG
BEND REGION. THE TRAILING EDGE OF THE MAIN TROF AS SETUP AN AXIS
OF ACTIVE ELEVATED W-E LINE FROM W VAL VERDE COUNTY TO SAN SABA
COUNTY WITH A SMALL DRY SLOT SEPARATING A SW-NE LINE OF
DEVELOPING CONVECTION IS ACTIVATING ON THE MID-LEVEL TROF OF THE
S/W NEAR THE BIG BEND REGION. AN ADDITIONAL CONVECTIVE CLUSTER IS
ALSO DEVELOPING FURTHER SOUTH OVER W WEBB COUNTY WITHIN THE SPLIT
BETWEEN THE POLAR JET AND SUBTROPICAL JET THAT CLIPS DEEP SOUTH
TX. THE BROAD HEIGHT FALLS EJECTING OUT OF THE HIGHER TERRAIN IS
SUPPORTING VEERED LOW LEVELS SUPPORTING WAA AND STRONG RETURN
MOISTURE FLOW ALONG THE RIO GRANDE VALLEY WITH TPWS RANGING FROM
1.6" NEAR KDRT AND NEARING 2" IN NE MEXICO. THIS INCREASING LOW
LEVEL FLOW IS CURRENTLY PROVIDING SUFFICIENT ELEVATED MUCAPES TO
500 J/KG FORECAST TO INCREASE TO 1000 J/KG THROUGHOUT THE MORNING
WITH STRONG MST FLUX TO INCREASE CONVECTIVE INTENSITY AND RAINFALL
EFFICIENCY WITH RATES UP TO 2.0"/HR. FURTHER NORTH...ORIENTATION
OF CELL MOTIONS WILL BE MORE ALIGNED TO SUPPORT SOME TRAINING;
WHILE FURTHER SOUTH CELL MOTIONS WILL BE SLOWER AND BEING CLOSER
TO THE SPLIT IN THE JET...LIKELY TO SUPPORT SOME BACKBUILDING OR
UPSTREAM DEVELOPMENT AS WELL.

HI-RES CAMS ARE SUPPORTIVE OF THESE MULTIPLE CORRIDORS OF HIGHER
RAINFALL TOTALS WITH 3 TRACKS OF 2-3" TOTALS WITH LOCALLY HIGHER
AMOUNTS WHERE MERGERS OR SOME TRAINING OCCURS...LEADING TO FLASH
FLOODING PSBL PARTICULARLY IN THE TERRAIN OF THE EDWARDS
PLATEAU/HILL COUNTY AND URBAN CENTERS (SUCH AS SAN ANTONIO).

GALLINA

ATTN...WFO...CRP...EWX...SJT...

[unome]

great site for live lightning on Google maps, use Southern Plains view
http://www.iweathernet.com/lightning/la ... oogle-maps


Area Forecast Discussion
National Weather Service Houston/Galveston TX
634 AM CDT THU MAY 19 2016

.AVIATION...
Area radar shows increasing thunderstorm activity over central Texas. Overall trends in observed convection and in HRRR runs indicate this activity should reach SE Texas later this morning into the early afternoon. Main concern for today is timing convection which has it reaching KCLL by 16-18z and then Houston terminals 19-20z this afternoon. It is quite possible that this timing may need to be sooner by an hour or two. The 15z TAF update and the 18z TAF package should provide opportunity to update for timing. TSRA should come to an end around 00-02z with CIGS lowering to MVFR levels, perhaps IFR with moisture lingering and light winds. Prior to any convection, obs show LIFR/IFR cigs for KCLL/KUTS. Expect CIGS to improve through the morning as convection approaches and frontal boundary begins to move north reaching Houston in the early afternoon. There could be some breaks in the ceilings as convection nears the region but think CIGS will be MVFR for most of the time until convection clear out of the area.

Overpeck

[sau27]

The 06z NAM 4km is definitely a head turner but also seemingly an outlier. It goes from painting 1-3 inches across Harris county in the 00z and 18z runs to 11.5 inches by tomorrow morning in the 06z. More amazingly, with the 06z it is showing most of the rain is dumped in two batches, 5 inches between 5 and 6 pm and another 3 inches between 8 and 9 pm. As I mentioned this run is an outlier so far compared to the other models, but is concerning if it were to verify.

Maybe some other members on here can shed some more light on the overall reliability and track record of this particular model during the past few rain events?

[srainhoutx]

SPC issued a Enhanced Risk for Severe Storms down to Coast to Matagorda Bay S to Corpus. That area is S of the front and will need to be monitored today.

[srainhoutx]

Regarding the 4KM NAM, sau27...think it is overdoing the precipitation totals. Even the 12Z HRRR only showed about 1-3 inches across the Hill Country and generally 1 inch amounts across SE Texas. That said will need to monitor later today for training storms along and N of the frontal boundary. That is likely why some of the shorter fuse meso models are aggressive with rainfall totals.

[srainhoutx]

MESOSCALE PRECIPITATION DISCUSSION 0222
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1053 AM EDT THU MAY 19 2016

AREAS AFFECTED...SOUTH CENTRAL TX

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 191452Z - 192100Z

SUMMARY...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO PROGRESS
SOUTHEASTWARD OVER THE NEXT SEVERAL HOURS. 1 TO 3 INCHES OF RAIN
ARE POSSIBLE THRU 21Z. FLASH FLOODING IS POSSIBLE

DISCUSSION...AN ONGOING CONVECTIVE COMPLEX ACROSS SOUTH CENTRAL TX
IS PRODUCING 1 IN/HR RAINFALL RATES WITH SEVERAL REPORTS OF FLASH
FLOODING THIS MORNING. A VERY MOIST (850 HPA DEWPOINTS OF 14-16
DEG C) AND MODERATELY UNSTABLE (MLCAPE OF 500-1500 J/KG) AIR MASS
IS IN PLACE SOUTH OF A STATIONARY FRONTAL BOUNDARY. LOW-LEVEL
SOUTHERLY FLOW OF 15-20 KT IS TRANSPORTING THIS AIR NORTH ACROSS
THE FRONTAL BOUNDARY SUPPORTING THE ONGOING CONVECTION.

OVER THE NEXT SEVERAL HOURS, THE BEST AXIS OF LOW-LEVEL INFLOW
WILL GRADUALLY SHIFT EASTWARD ACROSS SOUTH CENTRAL TEXAS. PWATS IN
THE AREA OF INFLOW ARE FORECAST TO INCREASE FROM 1.75" TO NEAR 2"
BY EARLY AFTERNOON AS MUCAPE INCREASES INTO THE 1000-2000 J/KG
RANGE. ADDITIONALLY, BROAD UPPER-LEVEL DIFFLUENCE WILL INCREASE
ACROSS THE OUTLINED AREA AS THE REGION REMAINS IN AN AREA OF
POLAR/SUBTROPICAL JET SPLITTING, AND THE DIVERGENT RIGHT ENTRANCE
REGION OF A POLAR JET STREAK APPROACHES. THESE FACTORS FAVOR
CONVECTION MAINTAINING ITSELF AS IT MOVES EASTWARD/SOUTHEASTWARD.
GIVEN INCREASING MOISTURE AND INSTABILITY...WOULD EXPECT RAIN
RATES TO GRADUALLY INCREASE WITH THE POTENTIAL FOR 1-2 IN/HR IN
THE HEAVIEST CONVECTION. WHILE THE ACTIVITY WILL GENERALLY BE
FORWARD PROPAGATING DUE TO A STRONG COLD POOL...THERE IS THE
POTENTIAL FOR REDEVELOPMENT ALONG THE SOUTHWESTERN FLANK GIVEN THE
ORIENTATION OF THE SURFACE BOUNDARY AND THE LOW-LEVEL INFLOW. THIS
COULD RESULT IN TRAINING OF CONVECTIVE CELLS AND LOCALIZED HEAVY
RAINFALL AMOUNTS.

THE HRRR AND HRRR-EXPERIMENTAL RUNS BOTH ARE IN AGREEMENT ON A
BROAD AREA OF 1 TO 3 INCH RAINFALL ACCUMULATIONS THROUGH 21Z.
GIVEN THE POTENTIAL FOR LOCALIZED TRAINING, ISOLATED HIGHER
AMOUNTS ARE POSSIBLE.

RYAN

ATTN...WFO...BRO...CRP...EWX...FWD...HGX...

[srainhoutx]

MESOSCALE DISCUSSION 0652
NWS STORM PREDICTION CENTER NORMAN OK
1013 AM CDT THU MAY 19 2016

AREAS AFFECTED...MIDDLE TX COASTAL PLAIN

CONCERNING...SEVERE THUNDERSTORM WATCH 182...

VALID 191513Z - 191645Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 182
CONTINUES.

SUMMARY...SEVERE STORMS MAY YET DEVELOP WITHIN THE EASTERN PART OF
WW 182 AS A CLUSTER PROGRESSES EAST AND PERHAPS ADDITIONAL STORMS
FORM SOUTH. ISOLATED WIND/HAIL SHOULD REMAIN THE PRIMARY THREATS.

DISCUSSION...A 35-KT EASTWARD-MOVING CLUSTER CENTERED OVER LIVE OAK
COUNTY HAS SHOWN AN INTENSIFICATION TREND IN INBOUND VELOCITIES OVER
THE PAST 20 MINUTES. THIS SUGGESTS POTENTIAL FOR STRONG TO ISOLATED
SEVERE WIND GUSTS MAY BE INCREASING AS THIS APPROACHES THE MIDDLE
COASTAL PLAIN GIVEN PRESENCE OF LOW-LEVEL EASTERLIES AND LOWER 70S
SURFACE DEW POINTS. FARTHER SOUTH...WEAK SHOWERS APPEAR TO BE
DEVELOPING NEAR THE CRP/BRO CWA BORDER. GIVEN SUBSTANTIAL VEERING OF
THE WIND PROFILES WITH HEIGHT /PER CRP VWP DATA/ AND MODERATE
BUOYANCY SAMPLED IN 12Z CRP RAOB /ALTHOUGH MUCH OF THIS WAS CONFINED
TO THE UPPER PORTION OF THE PROFILE WITH MODEST LOW-LEVEL LAPSE
RATES/...IT IS POSSIBLE THAT A STORM OR TWO MAY BECOME
SEMI-ORGANIZED WITH A RISK FOR SEVERE HAIL AND LOCALLY STRONG WINDS.

..GRAMS.. 05/19/2016


ATTN...WFO...HGX...CRP...EWX...BRO...

[Ounce]

TS Warning from Beeville to Goliad.

[Andrew]

As long as the line doesn't strengthen anymore and keeps on moving at the pace it is moving we should be alright. I am a little concerned about the heavier stuff between houston and San Antonio where a little meso-low is trying to spin up but we will see how that progresses through the day.

[srainhoutx]

MESOSCALE DISCUSSION 0653
NWS STORM PREDICTION CENTER NORMAN OK
1135 AM CDT THU MAY 19 2016

AREAS AFFECTED...MIDDLE/UPPER TX GULF COAST

CONCERNING...SEVERE THUNDERSTORM WATCH 182...

VALID 191635Z - 191800Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 182
CONTINUES.

SUMMARY...A RISK FOR ISOLATED STRONG TO SEVERE WIND GUSTS AND
MARGINALLY SEVERE HAIL SHOULD DEVELOP WITHIN A SPATIALLY CONFINED
CORRIDOR DOWNSTREAM OF WW 182. PROBABILITY OF DOWNSTREAM WW ISSUANCE
IS 40 PERCENT.

DISCUSSION...30-35 KT EASTWARD-MOVING CLUSTER WILL LIKELY SHIFT EAST
OF WW 182 THROUGH ABOUT 18Z. LOWER 70S SURFACE DEW POINTS ARE
CONFINED FROM GALVESTON BAY SOUTHWARD ALONG THE WEST/EAST-ORIENTED
PORTION OF THE WARM FRONT THAT EXTENDS ACROSS THE FAR NORTHERN GULF.
DOWNSTREAM CLOUD COVERAGE AND LEADING STRATIFORM RAIN IN SOUTHEAST
TX WILL LIKELY LIMIT APPRECIABLE MOVEMENT OF THE FRONT NORTHWARD
THIS AFTERNOON. THIS SUGGESTS THE THREAT FOR STRONG TO ISOLATED
SEVERE WIND GUSTS WILL PROBABLY BE CONFINED TO A COUPLE COUNTIES
INLAND FROM THE IMMEDIATE COAST.

..GRAMS/GOSS.. 05/19/2016


ATTN...WFO...HGX...CRP...EWX...

[djjordan]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1200 PM CDT THU MAY 19 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN WHARTON COUNTY IN SOUTHEASTERN TEXAS...
CENTRAL COLORADO COUNTY IN SOUTHEASTERN TEXAS... WESTERN
FORT BEND COUNTY IN SOUTHEASTERN TEXAS... NORTHWESTERN
JACKSON COUNTY IN SOUTH CENTRAL TEXAS...

* UNTIL 1245 PM CDT

* AT 1159 AM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR SPEAKS...OR
14 MILES NORTH OF EDNA...MOVING NORTHEAST AT 40 MPH.

HAZARD...60 MPH WIND GUSTS.

SOURCE...RADAR INDICATED.

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

* LOCATIONS IMPACTED INCLUDE...
EDNA...EAGLE LAKE...WEIMAR...EGYPT...MORALES...SHERIDAN...ALTAIR...ROCK
ISLAND...GARWOOD...CORDELE AND NADA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

[Ounce]

There's a particularly bulging part of the t-storm in Wharton county that looks to go by El Campo and Wharton to the north.

[unome]

catch a wave - look at the barrel on that thing...

http://weather.cod.edu/satrad/nexrad/in ... X-N0Q-1-96