Stx_Thunder

Multiple reports early this morning of impassable roads from another 8 - 10 inches in waterlogged Huntsville area, from the MCS activity going on in East TX since early yesterday evening (Wednesday). https://www.wpc.ncep.noaa.gov/metwatch/metwatch_mpd_multi.php?md=0208&yr=2024

Seeing reports of numerous road closures and water over roads in Madisonville and Huntsville areas from that persistent, slow-moving and pretty potent MCS (seeing pretty cold cloud tops near -80 C not far northeast of Houston area on satellite). Rainfall totals at or over 10 inches in some spots around that part of East TX also. A well-defined outflow should crawl into Houston within the next few hours and storms may persist a good part of this morning around there as seeing the LLJ maintaining at least 30 knots (seeing 35 now on Houston VWP radar still generally southerly in the lower levels). - - - - -https://www.wpc.ncep.noaa.gov/metwatch/metwatch_mpd_multi.php?md=0200&yr=2024 - - - ***** Later this week:

I think you’re gonna have more overnight wake ups in May now that we’re getting into peak MCS month (and especially coming out of a fairly strong EN winter). They tend to happen (and peak in intensity) more often during night. Anyone can see those multi-global model consensus thunder probability maps (and most other maps/model data on there) completely free & easily on https://weather.us I just post those on here to be informative CRP 0z observed sounding this evening showing pretty favorable convective environment over STX (more typical now getting into May). Just of course, lacking the necessary lift off to the north/east and doesn’t look like anything till sometime tomorrow/Tuesday. That shouldn’t be a problem in Houston area tonight (but could be on west end of it). Should be a pretty good thunder show there overnight as that MCS in East TX is taking its time propagating south this evening (could be higher end flood threat that region next several hours). WPC highlighting flooding likely in MCD for that region this evening. Also seeing a really good amount of positive CGs just like in the QLCS that moved through northern half of state last night.

High water rescues were going on in Kaufman, in the NETX MCS this afternoon. DFW radar estimating a southwest-northeast strip of significant rainfall. Embedded 7-inch storm totals in that area southeast of Dallas.

Must be a fairly strong shortwave coming into the state today. Despite pretty strong BL capping and warm 700Mb temps on sounding data down here early this morning, had an elevated storm still manage to get going nearby tapping into >8 ML lapse rates with a good amount of CGs (though thin & weak on lightning analysis), within the past hour or two.

Lots of 40s / lower 50s across the state Monday morning. Very comfortable 70 degree high & 50s DP down here (which are not common by this time of year), and had elevated storms moving around me both Sunday (with a good amount of small hail droppers, interestingly), and Monday mornings. Which was a good cherry on top. Last hurrah frontal airmass of spring outside was good while it “lasted”, very early this week. That looks to be about it for TX comfort season until later fall - Onto MCS month, coming up. That convective/supercell phenomena out there west/southwest of Laredo over the open Mexican terrain east of the Sierra mountains is MUCH more common during the Spring months, every year than you might be thinking. The orographic lift from those mountains further west is also what encourages the development out there over the flat terrain.

Just as I suspected on my first post from Thursday, 40s now in DFW by this evening with all the convective activity & resulting evaporative cooling effects going on behind the polar front today. Models not doing the best on convective placement. But GFS & 12z HRRR run this morning seem to have the ‘best’ handle on storms going on in the state today.

Both GFS & Euro last night forecasting generally 5 in. area totals for this weekend’s system/polar front or large linear MCS activity tonight between Dallas & Houston region. Doesn’t look like enough for sig flooding even though WPC has large (supposedly higher-end threat) excessive rainfall slight risk in D1 outlook/discussion, and despite parts of East TX seeing a good amount of rainfall in recent weeks. *** Should also add, HRRR not the most reliable as it always tends to overdo its convective depictions. Which is why stronger updrafts and severe can never actually be ruled out in elevated storms with enough DL/effective shear (especially nowadays). 12z observed DFW sounding this morning was also showing high elevated CAPE & LI just under 800 Mb layer. Even though ML lapse rates a bit meager (just about 7).

I think it has more to do with how late it is in the season (being right next to May now), so more people are not convinced that it would happen. Though it has before on climate history in the past 2 decades but even then, the cooling effects don’t last at all in this state when it does. March was dismally warm & humid for the most part (at least in the southern half), and it’s already been feeling a lot like summer with almost constant 70+ dew points in STX for some weeks now (save for just a few modest comfort-bringing fronts). So even though it doesn’t look like this weekend’s polar front is going to have enough gas to completely push off the whole TX coast, I’m really going to enjoy it as much as I possibly can as I should get down into the 50s for one night at least. After this, not seeing any other kind of comforting frontal airmass intrusions at all into the state on main models. Just total TX summer junk wx into early May with more 90 F temps showing up and growing HX. Away from any convective or MCS potential effects as we’ll be entering peak spring MCS month for the state in May. Everyone who’s not new to living in this state already knows what summer here is like Every year for literally about half of the entire year until October with 0 actual cold fronts through the state. Sometimes not until November here in STX. That just literally sucks every single year.

A little surprised nothing still hasn’t been mentioned at all about it on here (only being 2 days away now), but 2023 - 24 winter, is not actually done completely for TX just yet.. GFS has been consistent on it for a week now, and now that the AO has apparently entered a new negative phase, a very late season Polar front looks to edge through most, if not entire state by Sunday night (even though airmass duration is obviously going to be brief being next to May now). Canadian now showing lows Monday morning (22nd), in the 30s near DFW (I’m sure this is still significantly below normal for later April standards up there). 40s, San Antonio & Houston. Other models not as cold at that timeframe which explains why NWS is still being very conservative in state forecasts, but 12z NAM this morning (which always does best with these shallow polar and arctic air masses), at the end of run does show air temp at 50 F by Saturday evening in NTX. More likely 40s with forecast elevated thunder activity ongoing behind front Saturday afternoon, causing stronger evaporative cooling effects. Potential MCS (may be a few supercells/iso severe with 40kt DL shear on Euro) further south moving through the central/southern half ahead of front into the evening Saturday. -

Tuesday night looks to be most interesting for Southern half of TX just ahead of an abnormally deepening, incoming 500Mb Low tracking pretty far south (for the time of year) through the state near Midland, and then into Austin or DFW region Wednesday on both Euro & Canadian. Which would provide lots of support for lift for most of the state to erode any capping issues ahead of it and the cold front (even here in STX down to the lower Rio Grande plains/border) if that much more southerly track indeed happens. Trough attached south of the Low also looks to be at least neutrally-tilted (instead of positive). Pretty steep ML lapse rates around 8 C/km in STX and formidable DL shear 50 - 60 kts once again on Euro, along with ample CAPE to the surface on all 3 main globals (70 F+ DPs very likely in place over TX Coastal region ahead of cold front). Will see what CAMs show Monday (when Tuesday night timeframe comes into depiction). But Euro the past couple of days has been consistently showing a pretty sharp linear MCS, rapidly initiating from Laredo - San Antonio/Austin region around midnight. Damaging winds would likely be primary threat if indeed sharply linear (along with lots of lightning obviously but could be very frequent here in STX).

Supercell got going there in San Antonio a short while ago and dropped tennis ball hailstones in the northwest area. A good ways bigger than what the radar was indicating in the cell (1.25”). A couple of other reports around 2.00” in that same area of the city also.

Severe thunderstorm watch in effect for the mid-upper coastal region this morning: https://www.spc.noaa.gov/products/watch/ww0057.html https://www.spc.noaa.gov/products/md/md0274.html - - - - - Almost thought the typical BL capping was going to win out on the lower-mid coast because it took all night, but had a nice little multicell cluster pop up close by and fast an hour ago. Fairly frequent lightning, 2 very close CGs, and heard a few pieces of small hail on the roof just before the core moved off.

Looks like another decent thunder show for the mid-upper coastal region with building elevated instability later tonight/Thursday morning (cap/MUCIN strongly forecast by globals & CAMs to erode overnight with a fairly strong ML shortwave coming in from the west). Could have a couple of supercells near or just off the coast also with sufficient DL shear in place again around or just under 50 kts, but looks like strongest stuff will be offshore (sfc-based instability out there). SPC also has marginal & slight risk outlined for the mid-coast region tonight - through Thursday night. Despite more limited moisture further north, there looks to be another convective round & severe hailers Thursday evening/night in the Eastern half and towards Houston as that same cutoff parked Low over the desert southwest for about a week now (that caused last weekend’s storms & severe) begins to open up and move off to the east through NTX/OK, bringing stronger lift & colder mid-level temps over the eastern half of state tomorrow afternoon/evening.

Not seeing a real reason on SPC needing to post the severe thunderstorm watch tonight around here in STX. The Corpus Christi NWS office didn’t even bother to mention the typical “some thunderstorms may be severe” in the ‘rest of tonight’ section of zone forecast updates around midnight (because SPC posted that watch). The evidence of substantial boundary layer convective inhibition on Brownsville & Corpus 0Z soundings tonight caused the supercell near Zapata, TX to almost literally go kaput after it moved away from the Mexican border/lower Rio Grande river a short time ago. Still could see a good thunder show tonight around here, but more of the storms are individually cellular (unlike last night’s decent complex). Maybe a better chance or coverage of small hail here over the lower/mid TX coast. But seeing a more southwesterly flow now in the 850mb - 700mb layer on CRP vwp radar.

That HRRR supercell depiction near the coast is not likely as both 0Z CRP & BRO observed soundings this evening are showing a quite stable boundary layer with strong mixed layer CIN up to 300 j/kg and an already high-based LFC around 700mb (and being late at night on that HRRR depiction, but that model has also been overdoing storms lately). It’d take a very strong shortwave to overcome all that inhibition already in place along with the building nocturnal. Not to mention also, it’s (historically) rare to have large hail producing supercells further east very near the lower/mid TX coast. It’s always much more common further west and north away from the coast. Seeing new storms popping up out west ahead of that next shortwave in Mex, but even lightning activity on satellite out there is not looking impressive so far this evening and the discrete cells seem to be struggling some. That next incoming shortwave doesn’t look strong. https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=mex&band=EXTENT3&length=24&dim=undefined There'll probably be (elevated) storms in the region again later tonight or on Sunday morning and maybe a few stronger ones toward San Antonio and Houston areas with the front still hung up around there. But the atmosphere down here in STX is evidently still worked over and a bit subsident from an obviously strong shortwave last night that produced a large, slow moving thunder complex around here that lasted for a while.

000 WUUS54 KHGX 160829 SVRHGX TXC039-157-160900- /O.NEW.KHGX.SV.W.0037.240316T0829Z-240316T0900Z/ BULLETIN - EAS ACTIVATION REQUESTED Severe Thunderstorm Warning National Weather Service Houston/Galveston TX 329 AM CDT Sat Mar 16 2024 The National Weather Service in League City has issued a * Severe Thunderstorm Warning for... Southeastern Fort Bend County in southeastern Texas... Central Brazoria County in southeastern Texas... * Until 400 AM CDT. * At 328 AM CDT, a severe thunderstorm was located near Brazos Bend State Park, or 12 miles north of West Columbia, moving east at 30 mph. THIS IS A DESTRUCTIVE STORM FOR SOUTHEASTERN FORT BEND AND CENTRAL BRAZORIA COUNTIES. HAZARD...Baseball size hail and 60 mph wind gusts. SOURCE...Radar indicated. IMPACT...People and animals outdoors will be severely injured. Expect shattered windows, extensive damage to roofs, siding, and vehicles. * Locations impacted include... Angleton, Holiday Lakes, Bailey`s Prairie, Bonney, Brazos Bend State Park, Rosharon, and Damon. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. && LAT...LON 2931 9577 2943 9570 2934 9530 2907 9549 TIME...MOT...LOC 0828Z 290DEG 26KT 2933 9566 THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...2.75 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...60 MPH $$ Cady

https://www.spc.noaa.gov/products/watch/ww0055.html Another 3.00” max hailer about to come off Mexican terrain into TX right next to Laredo, going east.

Lots of CG positive strikes in that healthy supercell south of Houston, but nothing actually powerful on lightning analysis (all less than 150 kiloamps).

https://www.spc.noaa.gov/products/md/md0263.html

Must’ve been very prolific severe hail coming down in that same supercell when I saw Base reflectivity color max out on imagery over 80 DBZ (may have neared 90 DBZ seeing that tiny, light yellow speckle in right side blue strip area of 80 DBZ range), a short time ago.

https://www.spc.noaa.gov/products/watch/ww0054.html https://www.spc.noaa.gov/products/md/md0259.html

Seeing new cells developing between San Antonio and Houston TX, and a struggling cell near the Mexican border close to Del Rio. But they seem to be mostly heating/surface boundary induced as 500mb heights have slightly risen in South TX (above 580dm) this morning behind the departing shortwave causing the MCC in Dallas/Fort Worth area right now. The cells closer to Houston are showing some intensification/organization. But not sure if I can agree with SPC’s decision to upgrade to Enhanced risk on today’s outlook. Though they have upgraded to Slight risk now on midday D2 update (as I had also suspected yesterday for Saturday with the sufficient DL shear that had already been forecast in GFS & Euro runs all this week). - Deep 500mb Low is also still a bit too far out west over the California/Arizona/northern Mexico border. And shear parameters on this morning’s 12Z CRP observed sounding is not really conducive for a sustained supercell or mature MCS risk. But moreover cell clustering or MCCs (as been seen over northern half of TX today). It’s looking more like Saturday timeframe would be better for a more pronounced severe hail/wind potential over southern half of TX when the Low gets closer with better dynamics and cooling aloft coming in. Will see how 0Z sounding looks this evening, for tonight.

Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Fri Mar 15 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTH-CENTRAL TEXAS AND THE MISSISSIPPI/ALABAMA REGION... ...SUMMARY... Scattered strong to severe thunderstorms are possible across portions of south-central Texas and over parts of Mississippi/Alabama region. ...South-central TX... Confluent high-level flow over the middle of the CONUS will encourage surface anticyclone to settle south across the Plains today, though some weakening is expected across the southern Plains late in the period. Latest water-vapor imagery suggests a weak midlevel short-wave trough is approaching south TX early this morning. This feature is forecast to advance into the lower MS by 18z as associated 500mb speed max translates downstream into the central Gulf States. As a result, neutral-weak height rises are expected across south-central TX by afternoon. As this low-latitude short wave approaches higher-quality moisture, there is some concern that early-day elevated convection may develop. Several HREF members suggest isolated supercells initiate ahead of this feature. However, forecast soundings are quite capped so any activity should remain isolated. Of more concern is the strong surface heating anticipated across northeast Mexico into portions of south TX ahead of the synoptic front. Forecast soundings ahead of the boundary suggest convective temperatures will be breached as readings warm into the lower 80s. NAM sounding for DRT at 22z exhibits negligible CINH with SBCAPE on the order of 2500 J/kg with a temp/dew point of 83/62F. Strong surface-6km bulk shear and weak frontal convergence favor thunderstorm development and supercells appear possible. Large hail, some of it potentially bigger than 2 inches, is the primary risk with these storms. While convection should initiate due to strong heating, thunderstorms will likely linger well into the overnight hours as an increase in the LLJ is expected during the latter half of the period into this portion of TX. ..Darrow/Wendt.. 03/15/2024