The first severe weather watch of the day has been issued as we begin a fall severe weather event. The National Weather Service has issued a tornado watch for the Texas Panhandle, South Plains, and the Rolling Plains until 9 PM CT. Initial thunderstorm development is expected in the next two hours, with the possibility of discrete supercells. Large hail, damaging winds, and tornadoes are all threats with this initial activity. By early evening, we should see a squall line take shape and move east into Northwest Texas and the Big Country before taking aim at locations further east late tonight. Additional severe weather watches are expected later today and tonight for locations east of the current watch zone. Stay weather aware!
THE NWS STORM PREDICTION CENTER HAS ISSUED A
* TORNADO WATCH FOR PORTIONS OF EXTREME SOUTHEAST COLORADO SOUTHWEST KANSAS OKLAHOMA PANHANDLE WESTERN TEXAS INCLUDING THE PANHANDLE
* EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 100 PM UNTIL 900 PM CST.
* PRIMARY THREATS INCLUDE… A FEW TORNADOES LIKELY SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2 INCHES IN DIAMETER POSSIBLE ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
SUMMARY…THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY FROM WEST TO EAST ACROSS THE WATCH AREA THIS AFTERNOON INTO EVENING. THE MOST INTENSE STORMS WILL BE CAPABLE OF A FEW TORNADOES…LARGE HAIL AND DAMAGING OUTFLOW WINDS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES SOUTH OF LUBBOCK TEXAS TO 25 MILES NORTH NORTHWEST OF GARDEN CITY KANSAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).
First Day 1 Severe Weather Outlook for Monday Evening & Monday Night
The Storm Prediction Center issued the first Day 1 severe weather outlook about an hour ago. These outlooks are updated every five to six hours throughout the day. They contain more detail about specific severe weather hazards along with a synopsis of the setup. We continue to expect the severe weather threat to increase around sunset across the eastern Texas Panhandle and Northwest Texas. These initial storms have the potential to be supercellular with tornado and large hail potential. By mid-evening we should have a line of strong to severe storms extending from Kansas south through Oklahoma and Texas. That line will move east around 40 MPH tonight into Tuesday morning with a continued threat of damaging wind gusts and embedded brief tornadoes. Timing aspects have not changed from our evening blog update. Any thunderstorms that develop ahead of the line tonight or have the opportunity to become discrete could become tornadic. We’ll watch for those storms closely. We’ll have a complete forecast update with our usual Texas Weather Roundup around 6:30 AM.
…SUMMARY… SEVERE STORMS ARE EXPECTED TO DEVELOP INITIALLY OVER THE CENTRAL AND SOUTHERN HIGH PLAINS DURING THE LATE AFTERNOON AND EVENING. AN EXTENSIVE SQUALL LINE SHOULD FORM TONIGHT AND PUSH EASTWARD ACROSS PARTS OF OKLAHOMA AND TEXAS. TORNADOES…DAMAGING WINDS…AND LARGE HAIL ARE ANTICIPATED.
…SYNOPSIS… A POWERFUL 150 KT JET STREAK WILL MOVE EWD ACROSS NRN MEXICO INTO SWRN TX DURING THE DAY 1 PERIOD CONCURRENT WITH AN INTENSE MID-LEVEL TROUGH/LOW PROGRESSING EWD FROM THE 4 CORNERS INTO THE SRN-CNTRL HIGH PLAINS. A SURFACE LOW IS FORECAST TO DEVELOP OVER THE CNTRL HIGH PLAINS AND SLOWLY MIGRATE EWD WHILE A DRYLINE WILL EXTEND SWD THROUGH THE SRN HIGH PLAINS DURING THE AFTERNOON. A PACIFIC COLD FRONT IS FORECAST TO OVERTAKE THE DRYLINE DURING THE EVENING AND SURGE EWD ACROSS W TX AND THRU THE OK I-35 CORRIDOR OVERNIGHT.
FARTHER S…SURFACE-BASED INITIATION WILL PROBABLY BE DELAYED UNTIL THE LATE AFTERNOON. SCTD STORM DEVELOPMENT IS EXPECTED DURING THE 21-00Z PERIOD ALONG THE DRYLINE. AN AXIS OF MODERATE BUOYANCY IS PROGGED BY MODEL GUIDANCE /1000-1500 J PER KG SBCAPE/ AND STRONG DEEP-LAYER SHEAR. THE STRONGER UPDRAFTS WILL DEVELOP INTO SUPERCELLS AND THE INITIAL SEVERE RISK WILL INCLUDE LARGE TO VERY LARGE HAIL…SEVERE GUSTS…AND ISOLD TORNADOES. DURING THE EVENING…HODOGRAPHS ARE FORECAST TO ENLARGE /300-500 M2 PER S2 EFFECTIVE SRH/ ALONG WITH A GRADUAL MOISTENING IN THE PBL ACTING TO TEMPER NOCTURNAL COOLING AND MAINTAIN SURFACE-BASED OR NEAR SURFACE-BASED BUOYANCY PROFILES ACROSS SRN OK AND WRN N-CNTRL TX. AT THE SAME TIME…A RAPID PROGRESSION IN UPSCALE GROWTH IS EXPECTED TO OCCUR AS THE PACIFIC FRONT SURGES E AND STORM MERGERS OCCUR. IT IS PLAUSIBLE A SEVERE-WIND PRODUCING SQUALL LINE WITH EMBEDDED BOWS/LEWPS AND MESOVORTICES YIELDS SWATHS OF WIND DAMAGE AS THE WIND FIELDS INTENSIFY BY MID-LATE EVENING. LESS CERTAIN/LOWER PROBABILITY IS MAINTAINING CELLULAR MODES FARTHER E THAN ANTICIPATED AND/OR ADDITIONAL STORMS DEVELOPING AHEAD OF THE LINE WHICH WOULD PERHAPS FAVOR A GREATER TORNADO RISK. NONETHELESS…A GRADUAL DECREASE IN BUOYANCY FARTHER E TOWARDS THE ARKLATEX WILL TEMPER THE THREAT FOR WIND DAMAGE COMPARED TO AREAS FARTHER W.
Severe Weather Outbreak Possible Monday Night & Tuesday Morning
A severe weather outbreak is possible beginning Monday Evening and continuing all night into Tuesday. This setup has another dangerous factor in that it will be a nighttime event. The Storm Prediction Center has greatly expanded the Category 3/Enhanced Risk zone to include Northwest Texas, the Big Country, Concho Valley, and North Texas. This enhanced risk zone is where we’re most concerned about the threat of widespread damaging straight-line wind gusts. Considering how strong the winds aloft are I wouldn’t be surprised to see a few wind gusts exceed 75 MPH. Likewise strong wind shear will also mean a tornado threat all night. I encourage you to check back for forecast updates and to have a way to receive severe weather warnings tomorrow night. Scroll to the bottom of this blog for safety tips.
…SUMMARY… SEVERE STORMS ARE EXPECTED TO INITIATE ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS LATE AFTERNOON TO EVENING ON MONDAY. AN EXTENSIVE SQUALL LINE SHOULD FORM MONDAY NIGHT AND PUSH EASTWARD ACROSS PARTS OF OKLAHOMA AND TEXAS. TORNADOES…DAMAGING WINDS…AND LARGE HAIL ARE ANTICIPATED.
The simulated radar loop included with this post is courtesy of the 4 kilometer North American Model (4KM NAM) run from 6 AM this morning. No weather model gets everything exactly right so don’t expect the radar to literally look like what is shown here. Times on the graphic are in Zulu/UTC. Central Time is six hours back so 00Z would by 6 PM Monday, 03Z 9 PM Tuesday, 06Z is 12 AM Tuesday et al. We expect the first severe thunderstorms to initially develop across the eastern Texas Panhandle and near or just east of the Caprock around 5-6 PM Monday. These initial storms have the potential to be supercellular in an environment supportive of severe weather. Moderate instablity and strong wind shear will combine to produce the threat of golfball size hail, damaging wind gusts over 60 MPH, and the potential for tornadoes. Thunderstorm initiation may hold off right until sunset making this a nocturnal event.
Helicity (amount of spin) in the atmosphere Monday Evening will be quite high.
Surface moisture from the 12Z NAM at 6 PM on Sunday. The west edge of the moisture axis is the leading edge of the dryline.
Strong forcing/lift will cause a line of storms to quickly develop on the Texas Panhandle/Oklahoma border south into the Big Country and Concho Valley by the evening hours Monday. This line will race east into an environment characterised with very strong wind shear and an unstable airmass. A powerful low level jet and a maritime environment will allow the atmosphere to remain unstable all night along and east of the squall line. Unlike the spring months we can see severe weather threats continue all night in the fall/cool season. Winds around 5,000 feet above sea level will be above 70 MPH by midnight Tuesday across Northwest Texas and North Texas. The squall line will have the potential to bring some of that wind to the surface in the form of damaging wind gusts.
Very strong low level windshear means isolated tornadoes are possible within the line as it races east overnight Monday. Widespread wind gusts of 50 to 70 MPH will be the primary threat. Embedded circulations in the squall line may produce isolated tornadoes. Any discrete thunderstorms that form east/ahead of the line could become tornadic due to very strong wind shear. Some hail is also a secondary threat.
Severe weather is likely during the nighttime hours Monday into Tuesday Morning. A line of severe thunderstorms will race east across Northwest Texas, the Big Country, and Concho Valley late Monday Night into early Tuesday morning. The squall line should impact the Interstate 35 corridor from the Red River south into Central Texas between 3 AM and 6 AM with a damaging wind and isolated tornado threat. From there the line will continue moving east with a severe weather threat in Northeast Texas, East Texas, and Southeast Texas. Timing aspects have the potential to change as we get closer to Monday Night.
The threat for severe weather means you should have a way to receive severe weather warnings and have a severe weather safety plan. Know where to go if a warning is issued for your area. Have a plan and you’ll be good to go! The threat for storms is something all Texans live with. Folks in California live with earthquakes and those along the Gulf Coast live with hurricane threats. There is no reason to be fearful of this upcoming event. I was scared to death of storms as a kid – like beyond scared. I dealt with that fear by learning more about weather. Now I chase storms and have a better understanding of the mechanics of severe weather. The chance of a tornado hitting you is tiny. Even a large tornado (which we’re not expecting) is small compared to the size of a county. Have at least two ways to receive warnings, have a safety plan practiced and ready to go, and you’ll be just fine!
Your Sunday Forecast & Enhanced Risk of Severe Weather late Monday
Good morning and happy Sunday! Just a quick update for everyone on the outlook for today, plus a first look at the Enhanced Risk of severe weather for late Monday into early Tuesday. Light rain showers continue in a band stretching from west Texas into western north texas this morning. We expect this will be the trend today with additional showers and a few isolated thundershowers to develop and traverse this region of the state today and into tonight. For today, here’s an overview of the rain chances and a peek at the simulated radar of how things may look over the next 15 hours. Why 15? That’s as far out as this particular model reaches… 😀
The severe weather threat for tomorrow is increasing. The Storm Prediction Center upgraded the outlook to an Enhanced Risk for the period from Monday afternoon into early Tuesday. Very strong dynamics will be in place by Monday afternoon with a strong system overhead, plenty of moisture, a crashing cold front and sufficient instability and shear to produce a chance for isolated supercell thunderstorms to develop across parts of the eastern panhandle, northwest Texas and west central Texas by Monday evening. During the late afternoon/early evening timeframe, when the storms are more isolated, there will be a threat for a few tornadoes. As we get into the 7 to 9pm timeframe, these storms are expected to quickly evolve into a squall line of strong storms along the leading edge of the cold front and blast east across the northern half of the state and towards the I-35 corridor within the midnight to 2am timeframe. Greatest threats with this line of storms will be the potential for very strong winds and damaging hail. Crazy as I may be, I’ll be chasing this Monday evening, but David will be manning the weather desk and will provide updates for everyone throughout the night.
Severe Weather Expected Monday Night into Tuesday – Be Ready!
Let me start out by saying we haven’t had too many overnight severe weather threats in Texas over the past couple of years. Combine that with the notion that we don’t get severe storms in the fall and there is the potential for folks to be caught off guard Monday Night and Tuesday. Fall is our secondary severe weather season in Texas and we have had significant severe weather outbreaks in the overnight hours back in the 2000s. I’m not saying this is going to be a major event for Texas but we are going to have the ingredients coming together for a very busy period starting Monday evening continuing into Tuesday. This means severe weather will be occuring when most folks are asleep and we really need to stress that concern. Have a severe weather safety plan ready and especially have a way to receive severe weather warnings Monday Night and on Tuesday.
The current severe weather outlook places the eastern two-thirds of Texas in a risk beginning Monday evening. We’ll initially have discrete supercell thunderstorms develop in the Texas Panhandle and West Texas. These initial storms will be capable of producing large hail, damaging wind gusts, and tornadoes. After a few hours we’ll see those discrete/first storms and new storms congeal into a squall line. This squall line will move east into Northwest Texas, the Concho Valley, and Big Country by late Monday evening. The line of storms will have a slightly lower hail threat but an increased damaging wind threat. Isolated tornadoes will remain possible especially in enhanced cells of the squall line. Any sustained cells that develop ahead (or east) of the squall line will have to be watched for tornado potential. CUrrent timing has the squall line approaching the Interstate 35 corridor from the Red River south through North and CEntral Texas during the 3 to 6 AM timeframe Tuesday. Damaging wind gusts, pockets of hail, and isolated tornadoes will continue even in the overnight hours. The line of storms will continue to move east on Tuesday bringing a severe weather threat to Northeast Texas, East Texas, and Southeast Texas. We may see localized flooding in Northeast Texas.
Winds at 500 millibars at 12 AM Tuesday from the 0Z NAM. Speed is in knots.
Winds at 850 millibars 12 AM Tuesday. This is around 5000 feet above sea level. Also from the 0Z NAM.
Surface based instablity values at midnight Tuesday from the 0Z NAM. The instablity axis is moving east with the line of storms.
These three images are off the just out 0Z North American Model (NAM). The first two impacts show wind fields at midnight on Tuesday while the third image is of surface based instablity at the same time. What I think is most noteworthy are the last two images. You can see a ‘virtual’ squall line depicted by the model across Northwest Texas and the Big Country. Winds ahead (east) of the squall line are blazing with a low level jet of 65-75 MPH! Those winds veer to the southwest with height providing an insane amount of wind shear for Monday Night and Tuesday Morning. That kind of wind shear isn’t all that unusual with dynamic storm systems in the fall and winter months. WHat makes this setup concerning is that we’re going to have a sizable amount of instablity in place at the same time. More than enough instablity with a extraordinary amount of wind shear and moisture all spells the potential for severe weather Monday Night into Tuesday morning. Low-level wind shear will be very strong and that’s why we’re talking about a tornado threat. A linear mode (squall line) will reduce some of the tornado threat Monday night but definitely not eliminate it. The strong thunderstorms will also have the potential to ‘mix down’ the strong winds aloft and thus we’ll also be dealing with a fairly substantial damaging wind threat. Nothing is written in stone and I’d expect spatial and timing changes as we get closer to Monday.
This does have the potential for be one of our more significant overnight severe weather risks we’ve seen in some time in Texas. I encourage you and your family to have and practice your severe weather safety plan. Plan on having a way to receive warnings Monday Night into Tuesday morning. Most smartphones will alert you to tornado warnings via the Wireless Emergency Alert System – the same way you get flash flood warnings and amber alerts. NOAA Weather Radios and other smartphone apps are also great ways to get warnings. Don’t count on getting your warning off social media in real-time as algorithms may display them several hours later in your newsfeed!