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vbhoutex wrote:I posted this in the Winter Weather forum too. What is one to do?
What a difference one day makes!!! Yesterday I was in shorts and tshirts with light rain and 78F. Today I'm in jeans and long sleeves with rain and 48F!!
Can't even figure out which thread I should be posting in, this one or the non-winter thread
CajunMama wrote:As hurricane girl used to say, "Holy Crap
. Significant severe weather event including the potential for strong tornadoes increasingly likely this afternoon through Tuesday.
Heavy rainfall and flash flooding also likely on Tuesday.
SPC has upgraded the severe threat to a moderate risk for much of central and north TX.
Discussion:
Powerful upper level storm system will move slowly into the southern plains today/Tuesday with widespread downstream thunderstorm development over TX. Parameters appear to be coming together for a widespread severe weather event across much of the state this afternoon-Tuesday. Combination of increasingly cooler air aloft over heated surface air, strong jet stream dynamics, tremendous wind energy, and favorable instability all point to severe weather including tornadoes…a few strong.
As large scale forcing increases this afternoon over central TX, expect to see rapid development of isolate supercells capable of very large hail (baseball size or larger) and tornadoes. Meso scale models show numerous supercells developing in the 300-800pm period this evening roughly along the I-35 corridor in central TX with fairly rapid upscale growth into a large line of severe thunderstorms extending from SW MO to S TX overnight/early Tuesday. Initial cells will be a higher tornado threat (see SPC moderate risk outline below) in the region of favorable backed low level flow lending strong low level shear in a very moist air mass. Strong squall line (possible bow echo…line of thunderstorm with widespread wind damage) appears possible after midnight across central and SC TX in the region of strong jet dynamics and favorable low level Gulf inflow (low level jet of 50kts+ over the middle/upper TX coast). Strong mid level flow of 60-80kts plowing into the underside of the upper level storm and the backside of the squall line suggest wind damage is likely with this line. Surface wind gusts to 60-70mph will be possible with the squall line.
Line should approach our western counties between 200-400am and then slow some reaching the I-45 corridor between 600-1000am. Still some questions on timing as the models slow the line as the main upper storm slows down however strong cold pool generation could help shove this line faster to the east than the meso models are suggesting. Some concern than meso low formation on the line just north of SE TX could result in a buckling and slowing/stalling of the line over some portion of the area on Tuesday into Tuesday night which would keep a severe and then significant flash flood threat into Tuesday night.
Severe Impacts:
Damaging winds of 60mph or greater appear to be the greatest threat at this time with large hail and tornadoes a close second. Wind threat will increase overnight into early Tuesday with the greatest tornado threat this evening and then again on Tuesday after mid morning as the air mass heats. As is usual with these types of squall lines in SE TX brief tornadoes will be possible along the leading edge of the line with little warning.
Heavy Rainfall:
Starting to get a little concerned with a few of the models trying to slow and stall the line of storms over the area on Tuesday-Tuesday night. Moisture levels will be increasing to near 200% of normal today and with very favorable low level inflow off the Gulf and strong upper level divergence aloft the red flags for excessive rainfall are in place. Main question is does the storms move through or slow enough to drop 4-5 inches of rainfall in a few hours. Given the amounts of moisture that will be in place combined with the threat for slowing storm motions and training of cells some hefty short term totals will be possible. Models have been bouncing around with the idea of widespread amounts of 2-4 inches across various areas of SE TX and the latest HPC output shows a large swath of 2-4 inches over the area with a bullseye of 6.42 inches just east of metro Houston. Given the likelihood of high short term rainfall rates of (1-3 inches per hour) urban ponding/flooding on streets and areas of poor drainage is likely. Grounds are already wet from previous rainfall and run-off will be enhanced with this event producing rises on area watersheds. Flash Flood Watches have been issued for central and north TX and a watch may be required for parts of SE TX later today.
Hydro:
Several rivers are still seeing higher than normal flows from the last round of heavy rainfall and based on the current forecast several basins will see additional widespread very heavy rains tonight-Wednesday. Form the WGRFC in Fort Worth:
Moderate River flooding is likely on the: Upper Sabine, Upper Neches, and middle Trinity Rivers.
Moderate River flooding is possible on the: Middle Brazos, middle Colorado, upper Guadalupe, and upper San Antonio Rivers.
Rises to flood stage will be possible on smaller creeks and bayous across the state.
***Remember to never drive into high water even if it is “not deep”. Always turn around don’t drown!
Tornado Safety:
We have seen the large tornado outbreaks over the past year and TX has been largely spared in part due to the drought. The following tips are reminders of what to do if a tornado approaches your location:
Seek shelter in a strong sturdy building, abandon poor constructed housing
Abandon mobile homes for strong shelter, if no shelter is available lie flat in a ditch or low area and cover your head with your hands.
In a strongly built structure move to an interior room on the lowest floor of the location away from windows and outside facing walls. Cover yourself with pillows and blankets to protect from flying debris.
Never tie to outrun a tornado…abandon vehicles for strong shelter, if a strong shelter is not available lie flat in a ditch an d cover your head…DO NOT hide under freeway overpasses…they act as wind tunnels and increase the wind speeds under and around them
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