Let me start out by saying the weather across Texas for your Christmas Eve and most of your Christmas will be alright. Fog this morning across Southeast Texas and South Texas will burn off by lunchtime. Temperatures this afternoon will be above average across all of Texas. Some locations will top out in the 80s with new record high readings likely. Parts of the Rio Grande Valley could get dangerously close to 90 degrees this afternoon. San Antonio and Austin will be in the upper 70s, Houston in the low 80s, D/FW in the low 70s, Midland/Odessa in the upper 60s, Wichita Falls in the mid 60s, Texarkana in the low 70s, and Amarillo will be right around 50 degrees.
The forecast for this weekend continues to have some uncertainty with it. Confidence in a widespread/major winter storm is high – although where the rain/snow line sets up is still up in the air. Severe thunderstorms are possible beginning Christmas Night with an increasing severe weather threat on Saturday. Severe storms will also be possible on Sunday. Very heavy rain and a significant flooding threat will exist across North Texas, Northeast Texas, and East Texas this weekend. This will truly be an intense storm system with several different yet big impacts to Texas. Exactly where each ‘impact’ sets up will be determined on the star of the the show – our El Nino Bowling Ball! Its actually an intense upper level low but I like giving things nicknames. Just indulge me since it’s Christmas-time :). The track of the low is important since winter weather is likely to the north/northwest of its track with severe weather possible south/east of it. A 20 mile shift south now while it’s over the Pacific would result in a huge shift by the time it gets to Texas. We’re still 48-72 hours out and forecasting winter weather in Texas is difficult even 24 hours out. There will be forecast changes so check back for updates on Christmas and this weekend.
Severe Weather Potential
The warm side of the low will contain dewpoint values in the upper 60s to mid 70s. Such high moisture amounts are uncommon so late in the year and will contribute to unseasonably strong instability values as soon as Christmas Night. I believe Christmas Day itself will be quiet with light showers possible along and east of Interstate 35 from I-10 north into Oklahoma. It may not be the nicest day but it certainly will be warm and humid. There will be increasing potential for heavier rains and thunderstorms after midnight Saturday as the upper level low starts to get closer. The atmosphere will be unstable and wind shear values also look to be impressive. A cap will be in place so the threat for severe weather looks to remain marginal. If it appears a little more lift will be available then I’ll become more concerned about severe weather potential late Christmas Night into the early morning hours Saturday. At this time the Storm Prediction Center has highlighted a marginal risk of severe weather across all of North Texas, Northeast Texas, and East Texas. Isolated severe thunderstorms will be possible after midnight Saturday. Should they become surface-based (tap into the all the available instability and low-level wind shear) they could become supercells with a risk of large hail, damaging winds, and perhaps a tornado. This doesn’t look particularly likely right now but it can’t be ruled out.
A cold front will slowly push south on Saturday and Saturday Night. For the severe weather side of this system the front will be a focus point as a source of lift. The Storm Prediction Center has highlighted an elevated risk of severe weather on Saturday and Saturday Night for the Concho Valley, Hill Country, North Texas, Central Texas, Northeast Texas, East Texas, Central Texas, and the Brazos Valley. There is the potential for this to become a more active severe weather day with plenty of instability and impressive wind shear values. The strongest storms will be capable of large hail, damaging winds, and a couple of tornadoes. We’ll refine the severe weather forecast and any potential higher risk areas as we get closer.
As the cold front shifts south on Sunday so will the severe weather potential. The Storm Prediction Center has already highlighted South-Central Texas, Central Texas, Southeast Texas, the Brazos Valley, and all of East Texas in a risk of severe weather on Sunday. The risk area will likely change based on the eventual track of the low pressure. If the low tracks further south then the severe weather threat will likewise move south. Any northward shift would bring the severe weather risk further north. Damaging wind gusts appear to be the biggest threat on Sunday right now.
Heavy Rain and Flooding Potential
The El Nino Bowling Ball Low will have a ridiculous amount of moisture to work with for a December storm. Truthfully this system will have the dynamics of a winter system thanks to the strong jet stream while moisture levels look more like something we’d see in the late spring. Nothing good happens when those two ‘environments’ combine. Widespread rainfall amounts of 3 to 5 inches are likely across North Texas, Northeast Texas, and East Texas. Isolated totals of 7 to 10 inches are possible across the eastern half of North Texas and Northeast Texas. Rain totals of 1 to 3 inches are expected across Southeast Texas and Central Texas – highest in the north and lower to the south. Liquid-equivalent precipitation totals will likely end up in the half inch to two inch range across the Texas Panhandle, West Texas, Permian Basin, Concho Valley, Big Country, and Northwest Texas. By that I mean how much ‘liquid’ is measured after any winter weather accumulations melt.
The risk for flash flooding and significant rises on rivers/lakes will be high across North Texas, Northeast Texas, and East Texas beginning this weekend. River rises will likely push some back into major flood stage along with big rises on some lakes. Those flooding issues could continue for a couple weeks as water takes time to move downstream. Ground vegetation is dormant which all but eliminates the amount of water vegetation can absorb. It’s not like it matters since the ground remains saturated from rain events back in November and earlier this month. Almost any rain that falls will run off and result in a high-end risk for flooding. Hopefully we can get by without too much life-threatening flash flooding but that concern certainly exists.
Winter Weather Aspect
I know this is why most of you are reading this forecast. There will not be any snow on Christmas. The primary time-frame for our upcoming winter storm will be Saturday Night, Sunday, into the first half of Monday.
Here is the same graphic with city names.
Confidence in a significant winter storm impacting parts of Texas this weekend is high. Confidence on where the heaviest snow accumulations will fall is lower. Several inches of snow does appear likely to accumulate across all of the Texas Panhandle, South Plains, Rolling Plains, West-Central Texas, the Permian Basin, Far West Texas, and the higher elevations of the Davis and Alpine mountains. Widespread snow accumulations of 4 to 8 inches seem likely with some localized/isolated amounts topping out much higher. Beyond that we’re still too far out to get specific and don’t be shocked if the snow numbers change. The ‘bowling ball low’ will be intensifying as it moves across Texas. A tight pressure gradient will set up across the western half of Texas and that means wind. Wind gusts in spots will likely approach 60 MPH with more common values in the 40 to 50 MPH range. A true blizzard in every definition is becoming more likely – even in locations where snow amounts may be lighter. Blowing snow and snow drifts possibly being measured in feet could occur. Travel will be extremely treacherous and perhaps life-threatening in the worst conditions. Blizzard Conditions are most likely to occur on Sunday and Sunday Night in the blue-shaded region of the map. Don’t plan on traveling in that time-frame. If you have travel plans that take you through those regions on Sunday or Monday – change them.
Winter weather accumulations will be lighter in Northwest Texas, the Big Country, the Concho Valley, and lower elevations near the Mexico border. Strong winds will still result in whiteout conditions later on Sunday and Sunday Night. I have not included any potential ‘mix’ on my graphic since we’re still too far out to accurately determine the location of the rain/sleet/snow line. There is the potential for significant freezing rain (ice) and sleet accumulations in a narrow zone between the rain and snow line. The track of the low will play a critical role on how far east the snow can make it on Sunday Night and Monday. Some solutions are showing rain changing over to snow for North Texas and into parts of Central Texas on Monday. I’ve highlighted that potential on the graphic. This aspect of the forecast is extremely low confidence and I guarantee there will be forecast changes. If things end up warmer or the low tracks further northwest then the rain/snow line will be further west/north. If the low tracks further south/east or cold air moves faster than there is the potential for snow in portions of North and Central Texas – including in the D/FW Metroplex. Warm ground temperatures and the lighter nature of the snow on Monday would keep surface roads just wet but there may be some issues with bridges/overpasses. Its all dependent on the factors I listed above and its far from written in stone.
Will it snow in D/FW on Sunday Night/Monday? Its becoming more possible – but any accumulations would be on the light side and on the grass and elevated surfaces.