DFW’s mild winter is about to come to an end. A very impressive Arctic airmass will be building and plunged south into the heartland of the CONUS over the weekend, indicative of a ~1045mb high pressure system. This all teleconnected very well with negative EPO, negative WPO, negative AO, and negative NAO. This will produce the coldest weather for this winter by a long shot for DFW. There is an increasing concern that temps could fall below 10°F at the coldest point which is the threshold for severe cold for this region and necessitate Hard Freeze Warnings for the area. This type of cold can damage agriculture and infrastructure this far south as we saw in February 2021. At the very least, we are confident temps will fall to the teens Monday and Tuesday next week for DFW with high temps struggling to get out of the 20s. At this time, it is not anticipated that the cold will be anywhere near the magnitude of February 2021, or last as long. There is a small chance that we may see some impactful wintry precipitation Sunday night into Monday. Not all of the models are on board with this scenario, but enough are that we will be monitoring that closely. Of course, any frozen precipitation will only exacerbate the cold. If you have not winterized your homes, now will be a good time to do so.

The National Weather Service office in Fort Worth is upgrading the Winter Storm Warning to an Ice Storm Warning for the western half of the Metroplex including Fort Worth for tomorrow into early Thursday. The potential exists for severe icing on top of the already 1/2 inch of sleet or so. There could be an additional 1/2 inch of ice accretion from moderate to heavy freezing rain tomorrow. This would make travel nearly impossible and hamper the improvement of roadways in this area until late Thursday or early Friday. This amount of ice could potentially cause widespread power outages, especially in areas that have above ground power lines. The weight of the ice can bring them down, and also bring down tree limbs that fall on the power lines. Travel in Tarrant, Parker, Hood, Denton, Johnson, and Wise counties is strongly discouraged.

An Acrtic airmass is barreling south and should reach the DFW Metroplex by sunrise Sunday morning. Temperatures should plummet 10 to 20 degrees with a an hour or so behind the front. Sunday’s high temperatures are occuring now. This airmass is very dense but shallow, only about 1 km thick vertically. It will also hang around most of the upcoming week.

As cold air advection intensifies Sunday evening, temperatures will drop below freezing all the way to Waco Monday morning. An upper level storm system will approach from out west setting the stage for freezing drizzle on Monday. This will start the icing process on bridges and overpasses. Because it is drizzle, roads may look fine, but are actually coated with a glaze of black ice. Motorists should be very cautious traveling on Monday.

Conditions will worsen Monday night into Tuesday as temperatures get colder and precipitation ramps up. Sleet will also be mixing in with the freezing rain. Total ice accretion from this event depends on several factors and not entirely known at this time. However, it is becoming clear that ice may cause major travel headaches from the DFW Metroplex north and west. There may be enough ice accretion to warrant a Winter Storm Warning for part or all of the forecast area. Please stay alert to changing weather forecasts and conditions.

Key Messages:

• Severe cold Arctic outbreak expected for Christmas. Arctic front arrives early Thursday.
• Very cold temperatures with lows in the single digits both Friday and Saturday mornings.
• Wind chill values will be below zero Thursday night into Friday morning.
• Very strong winds expected on Thursday behind the front.
• No snow or ice is expected outside of a few flurries.
• Temperatures to stay below freezing for 72 hours (from Thursday to Christmas Day)
• Pipes will burst if not properly wrapped and protected
• This will be the coldest Christmas since 1989.

A major Arctic airmass that has been building in Canada seeded by air from Siberia will plunge southward into the lower 48 this week. The high pressure associated with this airmass is progged to be some 1060+ mb and may challenge high pressure records for the lower 48. This will undoubtedly bring a severe cold snap to much of Texas for the holiday. Residents, especially those planning on being out of town, should prepare their homes by wrapping their pipes. Temperatures at the coldest point could potentially reach the upper single digits at DFW. This is cold enough to cause infrastructure damage in this region and is considered severe cold. Freezes will likely reach all the way into Northern Mexico and into the Lower Rio Grande Valley with this.

The Arctic front is expected to arrive on very early Thursday with plunging temperatures behind it. Temps will likely be in the single digits across all of North Texas by Friday morning with wind chills below zero. This will not be a repeat of the cold air outbreaks of December 1983, December 1989, or most recently, February 2021. We simply will not get that cold, nor is the longevity of this cold air outbreak expected to be that long. However, this will be the coldest Christmas since 1989 for DFW. Freezing temperatures are expected for about 72 hours from Thursday to Christmas Day. We are not expecting any ice or snow with this cold outbreak at this time. Residents are urged to take proper precations to winterize their homes, including wrapping exposed outdoor pipes. Pipes will freeze and burst in this type of cold.

UPDATE: The Winter Weather Advisory has been expanded to include all of the forecast area. The expectation is the precipitation will be a bit heavier tonight in the form of actual freezing rain and sleet. Ice accretion in the advisory area is expected to be up to 1/4 of an inch with isolated amounts slightly higher. Since amounts reaching 1/4 of an inch will be more isolated, they have foregone a Winter Storm Warning at this time. Regardless, this will be enough ice to cause problems on not only bridges and overpasses but secondary roadways as well. Thursday morning commutes could be very problematic. Temperatures are expected to be in the 24-28°F degree range in the advisory area. DFW Airport forecasted low is 25°F.

Temperatures dropped to the middle to upper 20s, a couple of degrees colder than most models, this morning across the Winter Weather Advisory area which was expanded to include Dallas and Tarrant Counties. Widespread freezing drizzle has been occurring. Motorists should exercise caution when commuting this morning for possible icy bridges and overpasses and black ice patches. The advisory now runs through noon on Thursday as another disturbance pivots across the area bringing more in the way of light freezing rain and sleet tonight into tomorrow. Temperatures should have no trouble getting into the mid 20s again tomorrow morning. Areas that fall below 28°F may have more widespread issues with all roadways.

We will continue to see one Arctic surge after another through the coming 7 days. The coldest of which will occur on Saturday night through Wednesday. There is confidence that we, at some point at DFW Airport, will get to 12°F or colder, which will make for the coldest temps since 1996. If the mercury reaches 7°F, it will be the coldest since December 1989. Regardless of how cold it actually gets, it does look like temps will reach severe cold category with dangerously cold wind chills approaching 10 below zero at times. Hard Freeze Warnings and Wind Chill Warnings will likely be needed at some point.

There will be a quick shot of sleet and snow with the Arctic front on Saturday. However, it will get shut off rapidly by the deepening cold air. Models are now coming into better agreement on a more significant winter storm (likely all snow) Sunday night into Monday. If we get a snowpack, it will only exacerbate the bitterly cold temperatures. This is still several days out and the forecast will likely undergo many changes. More on this potential as more data becomes available.

A potentially significant severe weather episode is unfolding for the forecast area later this afternoon well into this evening. The Storm Prediction Center has placed the entire forecast area in the Enhanced Risk category for severe weather. Please see the map below. The Enhanced Risk area is in orange, the Slight Risk area is in yellow, the Marginal Risk area is in dark green, the lighter green area means non-severe convection is possible.

Setup: A powerful upper level trough will be digging into the western portions of the state. A dryline will setup ahead of this system and begin surging eastward. Copious moisture advection from the Gulf will be pulled northward, indicative of dewpoints surging into the upper 60s/70s. CAPE (convective available potential energy) values in this moisture laden, warm atmosphere will climb to around 3000 to 3500 J/Kg with shear in excess of 50 knots.

What to Expect: Discrete cells should begin firing along and ahead of the dryline and possibly as far east as the I-35 corridor late this afternoon. These will rapidly become severe producing gigantic sized hail in the Enhanced Risk area. It will be possible for hail to reach baseball, or even softball, size in this type of environment. Over time these cells should grow into a QLCS (quasi-linear convective system) and push eastward with an attendant damaging straight-line wind threat. With the discrete supercells, especially ahead of the dryline, a few tornadoes cannot be ruled out. The tornado threat should wane as the storms form into QLCS. Another line of storms may approach the area later tonight along the actual cold front.

When: Wednesday, April 17, 2019 between 5:00pm and Midnight.

Please stay alert to changing weather conditions and heed any possible warnings that may be issued for your location.