Good morning and happy Wednesday! The initial frontal boundary has already begun moving through the northern panhandle this morning, and is expected to make it into or near the DFW metro area by noon today. This initial front will not be all that dramatic for much of north Texas as most of the colder air will lag behind by about 12 hours, give or take. Tonight and especially by Thursday morning is when it will begin to feel more like an arctic blast with increasing surface winds and steadily dropping temperatures.
Tomorrow, rain is expected to begin sometime before noon, then as temperatures drop during the day Thursday into the low 30′s and possibly upper 20′s across the northwest zones, the rain will begin to transition over to freezing rain with possible sleet mixed in as well. Exact roadway impacts are hard to determine at this point as it all will depend on where the freezing line sets up late Thursday and into early Friday. As always, elevated surfaces, including bridges, tree branches and power lines, will feel the first impacts with accumulating ice up to 1/2 inch possible. Road surfaces will not be as impacted until later in the event (early Friday morning) where surface temperatures drop below freezing, and if the precipitation continues for a long enough period after the surface temperatures drop below freezing. This is what we are continuing to watch closely as only one or two degrees in temperature fluctuation can make all the difference between wet roads and icy roads.
The next round of wintry precipitation is expected to arrive sometime late Saturday and into Sunday morning. At that point, temperatures will be at or below freezing and additional impacts are possible based on how heavy the precipitation ends up being and how cold the temperatures are at that time. Most of the medium to long-range forecast models are holding on strong to the possibility of icy precipitation over much of north Texas during both of these precipitation events. The shorter range models however, appear to be backing down a bit on the precipitation and chances for ice. What they are ALL in agreement on is the intrusion of very cold and sub-freezing air that will be sticking around for quite some time. As David mentioned in his earlier post this morning, the long-lasting sub-freezing temperatures may end up being similar to what we had during Superbowl in February 2011 when we had numerous days in a row of highs only in the teens and 20′s across north Texas. That said, today would be the day to get your pipes wrapped up, your cars fueled and your pets and plants protected from this protracted cold spell. If we get significant ice accumulation, power outages or rolling brown-outs are a possibility, so be prepared for that as well.
As an example of the diversity we’re seeing in the current forecast models, here’s a comparison between one of the short-range forecast models (The NAM), and one of the medium to long-range forecast models (The GFS), for the same time period…6am Friday morning. The GFS has been very consistent with the possibility of a large footprint of icy conditions across north Texas and down into parts of west central Texas. The NAM however, is showing much less ice and more rain across the same areas. As always, we will continue to monitor and keep you up to date on the latest as this event unfolds.