#7397 Postby dhweather » Mon Mar 02, 2015 2:54 pm
From: National Weather Service, Fort Worth
Date: Monday, 2 March 2015 13:33 CST
Good afternoon everyone,
Unfortunately, another winter precipitation event will be impacting most of North and Central Texas Wednesday through Thursday morning. Right now, sleet appears to be the main precipitation type, though some freezing rain and/or light snow may enter the picture in a few spots. While we're increasingly confident that some frozen precipitation - and travel impacts - will occur across our area, we're only moderately confident about amounts and expected road conditions. This is due the fact that there will be a race underway between the arrival of the true arctic, sub-freezing air, and the cutoff line for precipitation that'll be ongoing from N to S across the area Wednesday night. Timing will be critical with this upcoming event.
BOTTOM LINE: Most of North and Central Texas will experience frozen precipitation (mainly sleet) Wednesday afternoon/Wednesday night, with some of it lingering in Central Texas Thursday morning. Across North Texas, we don't believe we'll be facing as many impacts as we experienced with Friday's event. Nevertheless, some sleet will accumulate with temperatures in the upper 20s, and that'll likely produce slick conditions on elevated surfaces - and some roads - by late afternoon/evening Wednesday. Right now, we don't expect any significant power outages from DFW northward.
We have somewhat more confidence that Central Texas (especially along and S of a Lampasas to Waco to Athen line) may experience impacts due to higher amounts of moisture and lift. In these areas, a greater proportion of the winter precipitation may take the form of freezing rain, in addition to sleet. We thus have more confidence that slick conditions - and possibly some ice accumulations on power lines - will develop in these areas by Wednesday evening/night. Some of these areas in Central Texas may experience their most significant winter weather events of the season.
A significant amount of uncertainty still exists with this forecast. However, all of our emergency management, media, public safety and transportation partners should be watching this system closely, and considering preparations for another round of travel impacts during the Wednesday and Thursday timeframe.
TIMING: A transition from rain to sleet will occur in our northernmost counties between Noon and 3 pm, with slick roads/bridges likely from early afternoon onward. In the greater DFW area and I-20 corridor, the rain to sleet transition will take place between 2 pm and 4 pm, with some slick conditions possibly developing (at least on bridges) by late afternoon. South of a Lampasas-Waco-Athens line, the transition from rain to freezing rain and sleet should take place between 5 pm and 8 pm, with sleet continuing intermittently all night. Slick conditions in these areas should gradually develop and worsen after 6 pm, through the night.
AMOUNTS: Our estimates right now include up to 1/4" of sleet from I-20 northward (including DFW), with anywhere from 1/2 to 1" of sleet possible south of I-20. Some accumulations of freezing rain will also occur. These amounts are subject to change.
CONFIDENCE/ALTERNATE SCENARIOS: Our overall confidence in this forecast is moderate. Our main concerns are: a) the timing of the sub-freezing air (and <30 deg air) into the different parts of our area, and b) how much precipitation will continue to fall in these areas once the cold air is in place. The forecast should start to come into better focus by tomorrow afternoon, and certainly Wednesday morning, once the cold air nears Texas.
One alternative scenario would have the colder air arrive faster and deeper than previously forecast, with just as much - or more moisture. If this happens, sleet and snow amounts will correspondingly increase, and travel conditions will deteriorate significantly across all of N and C Texas. Another scenario would maintain the current timing on the arrival of the cold air, but decrease the amount of precipitation that we experience. Impacts would thus be diminished from what is forecast. Right now, both scenarios are unlikely. However, our partners should be prepared for the first alternative, which could conceivably result in greater icing impacts across N/C Texas.
We'll obviously be assessing all available data over the next 2 days, and refining the forecast accordingly. We'll issue another heads up e-mail on Tuesday. In the meantime, please don't hesitate to contact us if you have any immediate needs or questions.
Thanks,
Tom Bradshaw/Mark Fox
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The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or 
