Tag Archives: North Texas

Heat Advisories in Place Across North Texas & DFW Area

FWD Heat Advisory

As high pressure continues to build back east across the state, temps will be on the rise to dangerous levels by tomorrow and likely through the weekend.  Some parts of the state will see temps higher than they’ve been in quite some time. Heat Advisories have been put into effect beginning tomorrow at 1pm across parts of north Texas, including the Dallas/Ft. Worth metroplex.  With the increase in moisture and humidity over the past 24 hours, Heat index values tomorrow and again on Thursday will be topping out close to 105 across the region…and tipping 110 by the weekend.  This certainly has the potential to become deadly for anyone sensitive to the heat, or to those working outdoors during the afternoon hours.

FWD Heat Advisory

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Thursday doesn’t look much better with temperatures climbing an additional couple of degrees and Heat Index values following along right behind.  It’s this time of year that we talk a lot about the heat index which is basically how hot it “feels” outside at any given time.  How high the humidity values become plays an important role in calculating the resulting heat index value.  The more humid it is, the less evaporation occurs when you sweat.  That evaporation process is what helps to cool you off.  If the sweat can’t evaporate quickly enough, you’re much more likely to experience heat illness or heatstroke.  You also have to keep in mind that heat index values are calculated based on being in the shade, which means that if you’re out in direct sunlight, you can easily add a good 10 to 15 degrees to it.  Also a factor this year…we didn’t heat up as early in the summer season as we usually do, so we’re not really as acclimated to this as we normally would be by the first of August.

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Beyond Thursday, high pressure will center over the state and temps will continue to climb through the weekend and heat index values will top out near 110 for some parts of northern Texas.  That’s going to feel hotter than fried h-e-double hockey sticks!


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I’d like to say things will get better going into next week, but current mid to long-range forecast models are staying consistent with keeping this strong ridge of high pressure over Texas for at least the next 7 to 10 days.  Beyond that, there’s really no (reliable) way to determine when we’ll get our next break from the heat and see rain back in the forecast.  All we can do now is wait it out and see how we do as we get into meteorological fall…September through November.  The Climate Prediction Center outlooks below for those months are certainly looking optimistic!

SON Precip SON Temp

Severe Storm Warning for Johnson County till 5 PM

Severe Thunderstorm Warning for Johnson County in North Texas until 5 PM. Severe thunderstorms are entering the western part of the county from Cresson to Godley to west of Bono. These storms are moving northeast at 30 MPH and will impact much of Johnson county through 5 PM. Quarter size hail and wind gusts of 60 to 70 MPH are possible with the strongest storms. Cleburne, Joshua, Alvarado, Rio Vista, and Grandview are all included.


354 PM CDT THU OCT 2 2014






Lunch Time Update on Severe Weather Threat

Track today’s storms using our interactive radar at www.texasstormchasers.com/radar


It’s an unbelievably muggy afternoon across the eastern half of Texas with dewpoint values in the 70s to almost an unheard of 80 degrees in South Texas. This is the kind of atmosphere we see during June and July with summer heat.. not during October! That should help emphasis the type of atmosphere we have in place today. With such impressive moisture in place the atmosphere is almost like a powder keg and is very unstable. That’s part of the reason were going to have such a large area under the gun today and tonight as a strong cold front moves into Texas. Enough about moisture content lets get down to business and look over the new severe weather outlook.

The new severe weather outlook released at 11:30 AM does not contain and major changes. For the purpose of defining each severe weather hazard I’ve divided the graphics into a hail risk and a damaging wind risk. The risk for large hail will be highest when thunderstorms first develop this afternoon and for the first few hours of the event. The overall risk for damaging winds will increase as storms congeal into a squall line. That’s why you’ll see some discrepancy between the highest risk areas for hail and damaging winds. Starting off with the outlook for large hail we have an enhanced risk for much of North and Northeast Texas. This includes the D/FW Metroplex, Hillsboro, Sherman, Paris, and Canton. Severe storms containing large hail will be possible across Central and East Texas as well.


The risk for damaging winds is enhanced across Northeast and East Texas including Sherman, Dallas, Athens, Tyler, Longview, Paris, Mt. Pleasant, and Texarkana. Severe thunderstorms containing large hail and damaging winds will be possible across much of Central Texas, the Brazos Valley, Southeast Texas, and Deep East Texas. Waco, Killeen, Austin, College Station, Lufkin, and Jasper are all in a severe weather risk today. While not included at this time the latest high-resolution model data does suggest the severe weather risk may need to be expanded to include Southeast Texas and the Houston Metro as the squall line may continue there late tonight.


The timing for today’s severe weather hasn’t changed much from our earlier thinking. There have been a few showers and thunderstorms across western North Texas this morning. While they have not been severe they did give some locations brief heavy rain and a few loud claps of thunder. What interests me about those showers/storms is that they may have produced outflow boundaries. As we head into the afternoon hours these outflow boundaries could locally enhance low level wind shear. I only mention this because we’ve had this happen before during a squall line event. The High Resolution Rapid Refresh (HRRR) weather model suggests we may have a few discrete thunderstorms form by 1-2 PM across the D/FW Metroplex just ahead of what will become a squall line. With an unstable airmass in place any discrete thunderstorm that becomes supercellular will need to be watched closely for low level rotation. Any discrete supercell that interacts with an outflow boundary could have the ability to produce low level rotation and possibly even a tornado. This isn’t to say we’re going to have issues with tornadic supercells today, but there is a small chance the initial discrete storms could interact with an outflow boundary and give it a shot in North Texas.

ANIMATION: 12 PM through Late Tonight

ANIMATION: 12 PM through Late Tonight

The first thunderstorms along the cold front should begin to fire by 2-3 PM. There remains some uncertainty exactly on where the storms will fire but all indications are it will be just west of the D/FW Metroplex. That means storms will be maturing and likely strong/severe as they move through the I-35 corridor in D/FW. By the time they exit D/FW and move into East Texas there should be a mature squall line. The primary severe weather hazards with initial discrete storms will be large hail up to the size of golfballs, damaging wind gusts up to 65 MPH, and possibly an isolated tornado as I described above. Once storms congeal into a squall line the primary hazards will be damaging wind gusts up to and possibly exceeding 70 MPH and hail up to the size of quarters and possibly golf balls. Low level winds will be unidirectional and not particularly favorable for tornadic development. However I can’t rule out a brief spinup with embedded supercells or complex structures in the squall line.

I expect we’ll see our first severe weather watches by 2 or 3 PM across North Texas with additional watches across Central and East Texas later this afternoon and into tonight. Please remember to keep an eye to the sky and check back for updates this afternoon.

1045AM: Isolated Storms across Western North Texas


A couple showers and thunderstorms have developed west of the D/FW Metroplex over the past 30 minutes. Extending from Alvord and Decatur south to Cresson this activity is quickly moving north/northeast at 45 to 50 MPH. This convection is a sign of increasing upper level lift across North Texas as a strong upper level disturbance and cold front begin to enter the region. As of 10:45 AM this activity is not severe and the strongest cores are producing brief heavy rain and cloud to ground lightning. One or two storms may become strong to marginally severe through lunch-time.

After 1 PM focus will begin to shift to the approaching cold front as instability levels increase across North Texas. Initial thunderstorm development is expected between 1 and 3 PM just west of I-35. These storms could become strong to severe with large hail and damaging winds. Storm coverage will increase as they move through the I-35 corridor. A near solid line of thunderstorms is expected by the time storms move east of I-35. I’ll have a more detailed update on this afternoon and evening’s storm chances after 11:30 AM.

Severe Weather Expected Tomorrow

A strong upper level storm system along with a southward advancing cold front will slam into a strongly unstable, humid air mass on Thursday across North, Central, and East Texas. A severe weather event is anticipated tomorrow as a line of thunderstorms should develop along an advancing cold front by the mid-afternoon hours. Ingredients will be in place to support the risk of severe thunderstorms capable of producing damaging wind gusts and large hail. The Storm Prediction Center has placed portions of Northeast and East Texas in an enhanced risk of severe weather tomorrow running along and east of US-75 from Sherman to Dallas and north of Interstate 20 from Mesquite to Marshall. A larger area of severe weather risk includes much of North and Central Texas into the Hill Country along with the Brazos Valley and East Texas. Ingredients are coming together for the possibility of a severe weather outbreak with a line of severe thunderstorms.


An upper level jet will dip south into Texas by the late morning and early afternoon hours tomorrow. By the mid-afternoon this upper level jet should be favorably positioned in conjunction with an advancing cold front. Winds at 500 millibars or about 18,500 feet above sea level will be exceeding 45-55 knots. The minimum wind speed I like to see for more organized thunderstorms is 35-40 knots at 500 millibars so the upper level winds will support an organized convective mode. The reason we look for stronger winds in the upper atmosphere is that the winds will help blow precipitation away from a thunderstorm’s updraft thus allowing warm, unstable air to continue feeding into it. When upper level winds are weak precipitation has a tendency to fall straight down or into the updraft. When precipitation falls back into the updraft the warm/unstable air is cut off and the thunderstorm weakens. During the summer months we refer to those storms as popcorn storms since they go up quickly, produce a light of lightning and heavy rain, but quickly weaken and usually dissipate within 30-45 minutes often resulting in a localized microburst. Since winds tomorrow in the upper levels of the atmosphere should blow rain out of the updrafts we expected a more organized convective mode and longer lived storms.


If you’ve been outside today you know temperatures are quite hot and muggy. Temperatures are well above average across North Texas today and will be again tomorrow as surface temperatures climb into the lower 90s. One way to measure moisture in the atmosphere is the dewpoint temperature. The dew points this afternoon across the eastern half of Texas are in the 50s, 60s, and even 70s. Honestly today feels like an April or May afternoon which is usually not a good thing when you’re talking about a upcoming storm system in early October. With a very moist atmosphere in place ahead of the cold front tomorrow the atmosphere is going to become strongly unstable. Surface based convective available potential energy (CAPE) values will exceed 2,000 to 3,000 J/Kg by the afternoon hours Thursday. Those are fairly impressive values for October and in combination with the strong upper level dynamics and cold front could support an appreciable severe weather threat.



One unknown factor that is still causing some uncertainty is the actual placement of the cold front when thunderstorms begin developing Thursday afternoon. Some model solutions have thunderstorms developing east of I-35 and keeping the D/FW Metroplex and everyone west of I-35 will remain dry. Other models suggest thunderstorms will begin developing along a Nocona-Mineral Wells-LaLampasasine. The first storms will begin developing across Oklahoma and gradually build south along the cold front. Thus the first storms will develop near the Red River and build south into Texas as the cold front moves east. Hence where the cold front ends up when storms fire will determine exactly where the rain chances begin. Based on current data and the National Weather Service Fort Worth’s thinking the current forecast shows thunderstorms developing just west of the D/FW Metroplex and I-35/I-35W by the mid afternoon hours. Thunderstorm cocoverageill increase as the cold front/squall line moves into D/FW with a nearly solid line of storms by the time they end up east of D/FW and US-75/I-45 in the enhanced risk zone. This could chance and storms could fire further west or east and radically chance the overall storm chances for the D/FW Metroplex.

Due to the combination of favorable ingredients for severe weather once storms get going they will likely become strong to severe quickly with a threat for damaging straight line winds exceeding 60 MPH and hail up to the size of golfballs. Not everyone will be hit by thunderstorms tomorrow. Not everyone who gets a storm tomorrow will receive large hail or damaging winds. The overall setup favors a linear event (squall line) with low level wind shear unidirectional and marginal. The tornado threat will be low but not zero. Any individual thunderstorms that manage to stay by themselves for a while or interact with an outflow boundary could produce hail up to the size of hen eggs and exhibit some rotation. While weak low level winds will keep any tornado threat localized and marginal any supercell storms will have to be watched.

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