Arctic air to cause ice issues, hard freeze through Wednesday
After starting near the freezing mark this morning, temperatures have risen into the lower 40s, due to some peeks of sunshine. Temperatures once again falling to near the freezing mark tomorrow morning. With northerly winds staying elevated, wind chills most likely in the 20s again tomorrow morning. More importantly, an upper-level disturbance will approach the area from the west. This will increase atmospheric lift, which will create a wave of precipitation across the area, mainly between 4-10am. Many times these upper-level disturbances can overachieve both in terms of the strength of their lift and the precipitation they produce. For that reason, I have added in the possibility of frozen precipitation across Acadiana tomorrow morning, mainly along and north of I-10. Although, significant accumulation is not expected, some glazing could occur if we see more precipitation than currently modeled, which could lead to some slick roads tomorrow morning. Yes, the main action will come in Monday, but don't sleep on tomorrow morning either!
High-resolution models keep our highs buried in the mid-upper 30s tomorrow afternoon. Global models, such as the GFS and European models, have been too warm with the temperature forecast this weekend, so I've opted to go with the colder high-resolution models. Temperatures will fall below freezing again tomorrow night as the heart of the Arctic air makes its way towards Acadiana.
At this point, I have a hard time believing we get much above freezing Monday, if at all. The cold air will be driving into the area through Monday morning as an upper-level disturbance spawns a surface low across the western Gulf of Mexico. This will lead to a wave of precipitation, lasting from around 3am Monday until 3pm Monday afternoon. It's important to stress many times these disturbances come in earlier than predicted, so any preparations you would like to take need to be done tomorrow. In this window, precipitation could get quite heavy as moisture and lift move over a very shallow Arctic airmass.
Models have continuously come in more aggressive with ice accumulations totals through the day on Monday. A good model consensus is for the possibility of 0.25"-0.50" of freezing rain with an additional 0.20"-0.40" of sleet possible as models have also trended colder with the atmospheric profile. Of more concern is the freezing rain accumulation, which can add weight to trees and powerlines, causing damage. During the ice storm of January 1997, most areas saw ice accumulation of 0.50"-1," which created widespread travel and power outage issues. Some of the more aggressive models are flirting with those kind of totals once again. At the very least, expect widespread travel issues and road closures. Power outages could definitely become a concern if some of the more aggressive models verify.
Behind the precipitation, the Arctic air will continue to work southward. This will push our temperatures into a territory we haven't seen in many years, possibly decades. GFS model still going with a low near 13-15 degrees, while the European is showing lows in the upper teens to lower 20s. As of now, I'll still go with a compromise of about 15-18 degrees for the overnight low, but this aspect of the forecast is still rather uncertain. For comparison, a low of nine degrees was achieved in December of 1989, which remains the official all-time low for Lafayette, although we may have seen six degrees during an Arctic outbreak in the late 1800s. Another thing we have to be concerned about is the duration of freezing temperatures. I'm starting to doubt we get above freezing on Monday as the Arctic continues to move southward and precipitation is ongoing. Tuesday will be a close call as well, as forecast highs will be in the 32-35 degree range. IF we do not get above freezing on Tuesday, we could see below-freezing temperatures from some 48-60 hours! Make sure to protect the plants, pets, and pipes. Wrap exposed pipes and faucets!
Temperatures finally warm up for Wednesday and Thursday, although another potent system is likely to move through.