Texas Spring 2016

[DonWrk]

Wondering if we will be able to send the texoma spillway back over before the faucet shuts off.

[Ntxw]

HRRR shows some fairly slow moving storms popping up this afternoon near the I-20 corridor with on and off activity overnight into tomorrow.

[Ntxw]

Also from the Norman office. Makes it the first violent tornado of 2016 (EF4 or higher)

NWS Norman ‏@NWSNorman 31m31 minutes ago

NEW! The May 9th Katie tornado (W of I-35) is being upgraded to EF4 based on more intensive review of survey data. Updated PNS and map soon.

[Texas Snowman]

@NWSNorman -- NEW! The Bromide tornado rating is being modified to EF3. Updated map and PNS coming soon.

[TeamPlayersBlue]

New GFS upgrade today, some interesting new data inputs.
http://www.noaa.gov/noaa%E2%80%99s-prem ... imensional

[BrokenGlassRepublicn]

HRRR shows some fairly slow moving storms popping up this afternoon near the I-20 corridor with on and off activity overnight into tomorrow.

Just noticed that as well. DFW rush hour looks interesting.

[Texas Snowman]

@BigJoeBastardi: Hail and high water next 10 days southern plains, DFW/OKC looks like 2 biggest cities most under the gun overall. 2-4x ave rainfall

[Texas Snowman]

@BigJoeBastardi: Models seeing pattern that will produce alot of rain for eastern and Central Texas next 10 days. Devil in details https://t.co/FcVJHY6aep/s/7WjX

[Ntxw]

Pouring rain outside. Some wind. Second evening now after a very warm day.

[Ntxw]

There is also a weak boundary sitting along I-20 and just south. Meso analysis shows poten tial flooding overnight for some areas as storms continue to traverse west to east along this feature.

[jasons2k]

Morning update from Jeff Lindner:

Highly active weather pattern for the next week or longer….

Upper air pattern similar to 2015 in place over the southern plains with almost daily complexes of thunderstorms across TX. Overall trend over the next several days will be for surface boundaries and upper level disturbances to move closer and closer to SE TX and likely help generate convection with the help of daytime heating and a moist and unstable air mass.

Weak surface front over N TX this morning will edge southward into SE TX this afternoon. A few strong to severe thunderstorms will be possible along this feature late this afternoon from College Station to Lake Livingston. This weak boundary will sag toward the coast overnight with at least a chance of showers and thunderstorms as it progresses southward through the area. Boundary will push off the coast Friday morning with a slightly drier air mass moving into the region. This drying will be short lived and expect a humid air mass to return quickly on Saturday as the coastal boundary dissipates.

Forecast model disagreement increases late weekend into early next week as the next large scale storm system drops into the SW US and begins to eject disturbances across TX. Sunday night into Monday morning is potentially an active period with both the CMC and ECMWF showing a slow moving complex of thunderstorms across SE TX. There is certainly a heavy rainfall signal with 20-30kts low level inflow and PWS of 1.8 inches, but the GFS models is capped and dry during this period leading to low confidence. IF the GFS begins to trended wetter and toward the CMC and ECMWF then the potential for a heavy rainfall event will increase during this time period.

Pattern remains unsettled into next week with general troughing out west and disturbances moving across the region producing complexes of thunderstorms. Gulf of Mexico seems fairly wide open through the entire period supplying plentiful moisture. There appears little change in this overall pattern into late May and TX will remain under the threat for both severe weather and flooding rainfall likely late into this month.

Similar patterns such as the current pattern have produced some significant severe weather and flash flood events in May 2015, May 2006 and May 2000.

[weatherdude1108]

Pouring rain at work right now in north Austin. I have gotten 0.38 inches (prior to this rain) so far since Sunday. Nice!

[TexasSam]

Out of the blue comes this:
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
759 PM CDT THU MAY 12 2016

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
CENTRAL HARRIS COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 830 PM CDT

* AT 759 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED OVER GREATER
INWOOD...OR NEAR JERSEY VILLAGE...MOVING NORTHEAST AT 25 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...
HUMBLE...JERSEY VILLAGE...SPRING...SPRING BRANCH WEST...ALDINE...GREATER
GREENSPOINT...SPRING BRANCH NORTH...ADDICKS PARK TEN...NORTHERN
NORTHSIDE / NORTHLINE...KINGWOOD...WILLOWBROOK...ACRES HOME...FAIRBANKS
/ NORTHWEST CROSSING...GREATER INWOOD...WESTBRANCH...HIDDEN VALLEY...
SPRING BRANCH CENTRAL...BUSH INTERCONTINENTAL AIRPORT...SPLASHTOWN
AND CARVERDALE.

[Texas Snowman]

I am still amazed by the video of the violent EF-4 tornado near Wynnewood, Oklahoma earlier this week.

If you haven't seen this video yet, it's unreal.

Especially starting around the 1:25 mark. When that twister crosses the road, I don't know how it wasn't EF-5 at that moment. As violent as anything I recall ever seeing.

https://www.youtube.com/watch?v=z3FPNx0pExg

[gboudx]

Update from jeff on heavy rain potential next week:

***Active weather the next several days will bring several rounds of thunderstorms to the region***

Large scale upper air pattern will bring several storm systems across TX over the next 5 days each of which will produce a chance of heavy rainfall and severe weather.

Surface boundary has stalled this morning from Victoria to Pearland to Orange and may drift a few more miles southward. Strong surface heating will result in the “cooking” of this boundary and once temperatures reach the mid 80’s and the seabreeze begins to advance inland from the Gulf expect storms to fire along the seabreeze and old frontal zone. Weak steering flow again today will produce slow storm motions with rainfall of 1-2 inches in an hour or less. Instability will also be high once peak heating is reached with hail and damaging winds possible from pulse severe storms.

Saturday:
Another frontal boundary approaches from the north and slows into our northern counties by late afternoon. Air mass becomes unstable and expect storms to develop both along the front and the inland moving seabreeze. An isolated severe storm will be possible during this period also with large hail and gusty winds the main threats.

Sunday-Monday:

***Active period with flash flooding possible***

Weak frontal boundary stalls over the region on Sunday while a strong upper air disturbance approaches from the west Sunday afternoon and evening. Expect thunderstorms to develop both along the front and across the TX Hill Country and move into SE TX. Parameters are pointing toward 20-30kts of low level Gulf inflow, surging moisture levels, good low level focus with a boundary in place, and decent upper level venting suggestive of slow moving heavy rainfall.

Will need to watch this period very carefully for a slow moving or stalling thunderstorm complex with high intensity rainfall rates. Much will be focused on the meso scale so there is only so much confidence at this time…but the overall pattern looks favorable for heavy rainfall.

Wednesday-Thursday:

***Active period with flash flooding and severe weather possible***

Another strong disturbance will impact TX during this period with a frontal boundary stalled across SE TX. SW flow aloft really increases on Wednesday and will likely support widespread thunderstorm development…some severe and some with excessive rainfall.

This is still many days away…but model agreement is there to be concerned with this period.

Hydro:

Central, north, and east TX rivers remain well above base flow with several basins in flood. Water supply and flood control lakes are full or into their flood pools from the recent rainfall. Thunderstorm complexes over N and NC TX the last few days have added more water into the upper and middle Brazos Basin and the upper Colorado Basin.

Widespread heavy rainfall over the next 5 days will once again result in rises on area rivers…some may return to flood stage.

Addicks and Barker Reservoirs in western Harris County remain elevated and additional rainfall across these watersheds could result in return flooding on recently opened roadways in and around the reservoirs.

Rainfall Amounts:
QPF has been increased overnight into the 2-3 inch range for the next 7 days with isolated higher totals likely. Much of this will fall during a couple of time periods and given the moist air mass 2-3 inches in an hour will be possible. Think amounts will need to be increased more as confidence builds on location and timing of upcoming thunderstorm complexes.

[gboudx]

I am still amazed by the video of the violent EF-4 tornado near Wynnewood, Oklahoma earlier this week.

If you haven't seen this video yet, it's unreal.

Especially starting around the 1:25 mark. When that twister crosses the road, I don't know how it wasn't EF-5 at that moment. As violent as anything I recall ever seeing.

https://www.youtube.com/watch?v=z3FPNx0pExg

Wow. I've never seen anything like that so close.

Off-topic: I haven't looked at the DFW AFD's in a couple days, but I noticed they're no longer shouting at us in ALL CAPS. This will take some getting used to.

[TeamPlayersBlue]

Just got dumped on here in SL. 1.4" of rain in less tha 45 minutes.

[Ntxw]

HIgh temps around 70 the next couple days...that will feel amazing. -EPO ftw

[Brent]

HIgh temps around 70 the next couple days...that will feel amazing. -EPO ftw

It's gonna be awesome... I don't see anymore 90s for awhile. Probably not much above mid 80s which is pretty average

[vbhoutex]

Latest from Jeff Lindner is somewhat concerning:

**Active weather pattern next several days***

***Severe Thunderstorms and flooding rainfall possible***

Discussion:

Upper air pattern remains a stormy one for TX…looking very similar to May 2015 with large scale troughing over the SE US and a moist unstable air mass over TX which results in round after round of thunderstorms. This is a very dangerous pattern with respect to flash flooding potential especially given the saturated conditions and full rivers/lakes. Upper level trough over the SW US will help supply numerous disturbances across TX while short waves passing in the northern jet along the Canadian border bring weak fronts to stall over the region. Air mass is generally uncapped with little to no upper level ridging aloft (another similar feature to 2015).

Today:

Air mass is already moist and unstable and will only require modest heating into the mid 80’s to get things going. Seabreeze will advance inland while a weak front drifts southward. Hi-res models show the tow features colliding during peak heating over SE TX…and boom. Expect fairly extensive development of thunderstorms…some severe. Generally in these situations the storms develop along the boundary collision and then drift toward the S or SW across the region. Air mass become very unstable and expect a severe threat this afternoon and evening with large hail being the primary threat although damaging winds can’t be ruled out.

Storms should have more organization than the last few days which raises the concern for heavy rainfall as motions will remain slow. Easily could see 1-2 inches per hour with PWS of 1.5-1.8 inches over the region. Main concern is larger areas seeing higher rainfall rates compared to the isolated nature the last few days.

Could easily see 1-2 inches of rainfall with isolated amounts of 3-4 inches

Late Sunday-Monday:

***Very active period with heavy rainfall***

Strong short wave approaches from the west and with the frontal boundary still stalled over the region expect widespread thunderstorms. Severe threat may not be as high with this event as this afternoon given the time of day (overnight into Monday when instability is at a minimum). Heavy rainfall appears to be the main threat with cell training in a very moist air mass. Still not sure how this will play out, but the drier GFS has trended toward the wet CMC and ECMWF leading to more confidence in higher rainfall totals.

Will hit the entire area with a solid 1-2 inches with isolated totals of 3-5 inches possible. May need to go higher if confidence increases that any well organized thunderstorm complex slows over the region.

Tuesday-Friday:

Unsettled pattern remains with another strong short wave approaching in the Wednesday/Thursday period. Frontal boundary remains stalled on top of the region and expect additional widespread thunderstorms with both severe and heavy rainfall potential.

Hydro:

TX is not in a good position to accept additional heavy rainfall with rivers high, lakes full, and grounds saturated. Widespread high QPF over the next 5-7 days is deeply concerning given the conditions in place. Trend has also been to increase rainfall amounts and the expected upper air pattern and moisture levels point toward the potential for some significant or even extreme rainfall events across the state. This is certainly the type of pattern that can produce a foot of rainfall in a short period of time resulting in devastating flash flooding and much of the state is at risk over the next 7 days.

7_day Forecasted Rainfall Amounts:

http://www.wpc.ncep.noaa.gov/qpf/p168i.gif?1463231129