Winter Weather/Extreme Cold Threat 1/13-1/17

[UncleJuJu98]

Yep all the 06z models still going with that sleet freezing rain push. It's going to be some nasty weather for Alabama.

And it even has some heavy showers in there as well. So some people could get locally higher totals of icey stuff.

This will likely turn out to be a big impact event for central Alabama.

 

[UncleJuJu98]

A winter storm warning is now in effect for a good chunk of north Alabama

 

[UncleJuJu98]

Freezing rain totals for most of Alabama is no joke. A .10 of a inch is a decent bit. Let's hope the RAP/hrrr/ Nam are wrong.

 

[TileDude]

Add some sleet to that freezing rain with temps in the 20’s. Could be a mess. Birmingham NWS morning discussion mentions extending the advisories south to near Montgomery later today.

 

[UncleJuJu98]

Add some sleet to that freezing rain with temps in the 20’s. Could be a mess. Birmingham NWS morning discussion mentions extending the advisories south to near Montgomery later today.

Going to add the NWS bmx text to this post in just a second.

**Icy conditions can be expected every where except i85 and southward**

Key messages:

- Icy travel conditions expected for much of the area by Tuesday
morning.

- Dangerously cold temperatures and wind chills expected, especially
Tuesday night and Wednesday morning.

Southwest flow aloft continues Monday night, downstream of a
digging trough over the central CONUS and over top of an Arctic
air mass that will be advancing southeastward. A 500mb shortwave
will be lifting northeast away from the area. Some subsidence
along with mid-level drying in the dendritic growth zone (DGZ)
will result in a decrease in precipitation intensity or perhaps a
lull in the precipitation, before a 700mb speed max/weak wave
initiates an uptick in isentropic lift and associated light
precipitation overnight. Given the drying in the DGZ and the 850mb
0C isotherm remaining parked over our far northern counties until
late in the night, any snow chances will largely remain limited
to the far northern counties. But as the 925mb and surface
freezing lines advance southeastward, light rain will change over
to light freezing rain initially given the warm nose aloft and
then potentially to sleet as the near-surface air mass continues
to cool. There is some model variability in when/where the
subfreezing temperatures will be at the surface, but the general
model consensus suggests this rain-wintry mix transition zone will
move through the I-59 corridor around 9pm-midnight, and reach
just north of the I-85 corridor by Tuesday morning. With
temperatures dropping into the 20s overnight, travel will quickly
become hazardous with moisture on roadways plus the additional
light freezing rain/freezing drizzle/sleet beginning to freeze.
It takes very little freezing rain/freezing drizzle to begin to
cause travel impacts. Given that these impacts are beyond 36
hours, a winter weather advisory for the I-20 corridor/southward
towards the I-85 corridor has not been issued yet, but will
likely be issued on later shifts.

Bottom line is, icy travel conditions can be expected by Tuesday
morning everywhere except the I-85 corridor southward, and will
have to closely watch the freezing line as it approaches the I-85
corridor.

 

[UncleJuJu98]

Wow. Uhh this looks nasty

 

[MichelleH]

A little bit of snow, ok, fine. Freezing rain and/or sleet? Nope, go away. Too many people (including us) that only have electric heat to survive these dangerous temps coming. We really, really need a bust.

 

[KoD]

I'm glad I reupped on firewood yesterday but I hope I won't need it. Power outages in this weather will be brutal

 

[UncleJuJu98]

The 12z HRRR is awful for the i20 corridor. Atleast .15 inch of freezing rain. Good grief I hope this doesn't happen. Birmingham would be crippled.

 

[Flurry]

IMO, we’re heading towards a Winter Storm Watch for B’ham and surrounding counties to the south (possibly down to the Clanton area) with a WWA down to the Montgomery area…Secondary Low forming is throwing some curve balls

 

[Gawxnative]

Well a couple of local to me "notes"... Lows overnight ran about 5-7 degrees below forecast (21 here) but also some of the heaviest..thickest frost i can remember!!! On windshield it was at least 0.10-0.15 inches!!! I couls almost have made a medium snowball from the scrapings lol

 

[MikeP]

Ya'll please correct me if I'm wrong, but after today/tonight there will be more snow cover to our N/NW. How much, if any will that affect model output with regards to temps? And wouldn't evaporational cooling help if the precipitation was heavier? Looks like it won't be heavy enough however. I'm looking for anything (lol) that might get temps down even lower.

 

[MikeP]

Hmmm.

 

[MikeP]

Should have posted this one first

 

[Richardjacks]

I am on the road back to bham after a weekend getaway in Atlanta. I am stopping at my parent's house in Talladega to get a generator, that's how I feel about this one for Bham.

 

[Blountwolf]

Yeah, if we could just drop that 540 line about 200 miles to the south please? That'd be great. Entirely too much potential for freezing rain for my neck of the woods in Blount County, AL. I really hope the cold air aloft is being underestimated. Best case scenario would be for this to "bust" colder aloft and it all fall as snow. Anything else will be a mess. I'm still thinking NW MS is about to get hammered with snow, with a good swath across TN, with Muscle Shoals and Huntsville in AL having a decent shot as well - Cullman north. Models park that 540 line over that same area the whole time the moisture is around, with below freezing temps working their way southeast at the surface behind north winds. Hope for cold air aloft. Evaporative cooling. Something - because otherwise we have a serious mess incoming.

 

[Richardjacks]

A few things come to mind for these kind of forecasts:.
Upper level warmth or "warm nose" is typically underforecasted, the southwest flow aloft will have e plenty of warm air, don't be surprised if the warm layer winds up being warmer and deeper.
Also, sometimes in rain situations when the droplets/flakes melt in the warm nose, some of of that heat gets carried down. If the rain is hard enough, I have seen when surface winds have little to no advection...no warm or cold air moving in, surface temps rise. What's different here is that the arctic air will still be moving in, this should offset any of that warmer air being pulled down....assuming the rain is hard enough to even do that.

It's really going to come down to how much moisture is available. The arctic air will do a good job of wringing every bit out even with little isentropic upglide.

 

[JPWX]

A word of caution on the HRRR, NAM, and short term models. Don't be surprised if all that freezing rain/sleet it's showing turns out all snow especially for North MS into North Alabama. I'm afraid that they aren't handling or seeing the cold air that well. I do see freezing rain/sleet potential but more for Central MS into west-central Alabama.

 

[Blizzard1]

A few things come to mind for these kind of forecasts:.
Upper level warmth or "warm nose" is typically underforecasted, the southwest flow aloft will have e plenty of warm air, don't be surprised if the warm layer winds up being warmer and deeper.
Also, sometimes in rain situations when the droplets/flakes melt in the warm nose, some of of that heat gets carried down. If the rain is hard enough, I have seen when surface winds have little to no advection...no warm or cold air moving in, surface temps rise. What's different here is that the arctic air will still be moving in, this should offset any of that warmer air being pulled down....assuming the rain is hard enough to even do that.

It's really going to come down to how much moisture is available. The arctic air will do a good job of wringing every bit out even with little isentropic upglide.

Yes I agree with you here. It is going to be an atmospheric hand to hand combat with the cold incoming vs overcoming the SW flow. Those warm noses SO often seem to win these battles here in the I-20 corridor.

I remember getting so frustrated waiting and waiting for forecasted changeovers in the past that were incoming but ran up against a warm nose parked on I-20 and just hit a wall. I can easily see this happening this time and just ending up in a scenario identical to what you painted here.

I know it’s just part of the climate here but that still doesn’t remove the frustration of seeing places like Huntsville slated for 5” of snow while we are looking for ice.

 

[Blountwolf]

Yes I agree with you here. It is going to be an atmospheric hand to hand combat with the cold incoming vs overcoming the SW flow. Those warm noses SO often seem to win these battles here in the I-20 corridor.

I remember getting so frustrated waiting and waiting for forecasted changeovers in the past that were incoming but ran up against a warm nose parked on I-20 and just hit a wall. I can easily see this happening this time and just ending up in a scenario identical to what you painted here.

I know it’s just part of the climate here but that still doesn’t remove the frustration of seeing places like Huntsville slated for 5” of snow while we are looking for ice.

Yep yep - definitely a warm nose. It just needs to lose the fight a little further south please. 66 in Baton Rouge, 18 in Memphis. Combat indeed.