Update on Strong Cold Front...

Saturday, March 20, 2010

Today is the first day of Spring, and for the time being it feels like it. However, don't let that fool you, or the relatively nice start to the weekend lull you into a sense of complacency...

The much advertised line of showers and thunderstorms ahead of the strong Pacific front is progressing Eastward at about 25 mph this afternoon. It is nearing Beaumont as of 1:15p.m. It will approach Lake Charles between 2-3p.m. and Lafayette between 4 and 5p.m. This is a bit ahead of schedule from what I've been suggesting the last couple of days. Nevertheless, the chance for severe weather is virtually non-existent, and that's very good news. The main mitigating factor is surface instability and less than sufficient surface dew points. The rain will last for several hours this afternoon and evening. A little lightning and thunder is expected and brief gusty winds, but no severe weather is anticipated. Upwards of an inch of rain is expected with this system, but it will be a quick mover so this will negate a heavy rainfall or flooding threat.

The big story will come behind this system with much colder air taking over. Temperatures will begin falling this afternoon into the 50s with the onset of the rain, and the free fall continues tonight with temperatures falling
into the mid to upper 30s by sunrise Sunday....brrr! Adding insult to injury will be strong NNW winds on the order of 20-25 mph. That will create wind chills in the 20-25 degree range. You'll definitely want to bundle up as you head out to church services Sunday. While the rain ends, the clouds will hang tough well into Sunday. This is in response to potent upper level low on the backside of this advancing front. This ULL will track along the I-20 corridor diving SE from Oklahoma tonight. The close proximity of this feature will be responsible for keeping the clouds in place. No precipitation is expected across the area on Sunday, however, if you want to see snow (that's right snow!!!) drive north to North Louisiana or somewhere in the ARK-LA-TEX region. Heavy snow is expected up that way underneath this ULL (they'll be just N and W of the circulation Sunday). The cold air aloft generated by this system creates instability in the atmosphere and produces dynamic cooling which translates down to the surface. Thus, rain will change to snow overnight tonight, and continue through Sunday. No such weather here, but it is interesting to note this anyway. It will be a cold, cloudy, and blustery day Sunday with temperatures only topping out in the mid to upper 40s. Some clearing will be noted late as the ULL pulls away, but it will take until Sunday night to clear out completely.

We will deal with a Spring frost Sunday night/Monday morning as skies clear and winds decouple (slack off). Strong Canadian high pressure will settle into the area, and as skies clear late Sunday this set the stage for prime radiative cooling processes sending temperatures down into the low to mid 30s for most areas by sunrise Monday. Frost is likely proposition by this time, with the coldest locations even experiencing a late season light freeze. The immediate coast should avoid the frosty conditions with temperatures closer to 40, but I expect a decent frost even here in Lake Charles. Air mass modification begins under full sunshine Monday afternoon with highs rebounding to the upper 50s. From there, the temperature modification continues with near normal conditions by Tuesday afternoon after another chilly morning Tuesday with lows near 40. Another system hangs in the balance for Thursday, with a return flow established ahead of it on Wednesday. This next system will have the potential to be more favorable for severe weather as it drags its cold front through the area on Thursday, but that remains to be seen. I will begin to hone in on that Monday. This should hopefully set the stage for a beautiful end of the work week Friday, and pretty Palm Sunday weekend! Stay tuned!

Listen to the audio blog for complete details! More information will be posted later as I deem necessary depending on the evolution of the cold air and advancing ULL tonight.

Have a good weekend and God bless!
-DM-