Feb 13th/14th 2012 Snow/ice Threat

Euro sticks with the 2-3 inches for much of west and middle tenn, north ms/al could get an inch, ne ga mountains seem to do well.

This is literally going to be a nowcasting event. A little more or less waa, a little more or less evaporational cooling, a little more or less qpf will make all the difference with regard to p type, accumulations, etc.

The euro definitely has a freezing rain look for the knoxville area.

I mean if we get a little less waa, we could be talking some seriously good totals. I really hope that is the case.

The wrf from wright wx is sure starting to look interesting. If we do get frozen precip with this system it wont be the kind that we have been used to this season. Any snow event this season has been northern stream dominant and therefore really dry when it comes to moisture. This one will have PLENTY of juice.

I just worry about the dry air. I know I am in a good location as far as temps go but I have seen systems like this be nearly past us before snow starts reaching the ground. At least we have a chance.

OHX

SOME INTERESTING THINGS NOTED...THE LATEST NAM MODEL IS COLDER
THAN OTHERS...INDICATING A PERIOD OF ALL SNOW ACROSS THE AREA
BEFORE A LATE NIGHT TRANSITION TOWARD LIQUID. THIS WOULD SUGGEST A
GREATER SNOW ACCUMULATION POTENTIAL. ALSO...A DEVELOPING WARM NOSE
WITH COLD AIR ALOFT (NEAR -25 DEG C 500 MB) WILL CREATE STEEP MID
LEVEL LAPSE RATES. FORECAST SOUNDINGS SHOW TOTAL TOTALS INDICES
CLIMBING INTO THE LOW TO MID 50S. THIS COULD LEAD TO SOME
CONVECTIVE ENHANCEMENT OF PRECIPITATION...PERHAPS SOME LOCALLY
ENHANCED BURSTS OF SNOW OR SLEET WHICH COULD MAKE THINGS
INTERESTING...AND MORE DIFFICULT TO FORECAST.

Wow, it's hard not to get excited after reading that!

18z GFS looks NAM-ish. I think Tuesday morning is going to be fun.

any early snow projections for Knox, stovepipe?

Well here is what the 18z GFS is saying verbatim:



It sounds to me like we could start the day with some rather heavy snow that might have sleet or freezing rain mixing in before ending up as all rain later on. It's a recipe that I'll gladly take this winter. That could cause chaos in Knoxville.

I have no idea how much could potentially pile up during that mess but we should get a better idea when we get into better short term model range and can see what the RPM, RUC, and HRRR have to say about it. Definitely going to be fun to watch.

Time of day, evap cooling, gulf moisture, possible convection... all good things!

Toot is right, if the Wright Weather simulated radar is to be believed, p-types are looking better than expected for this despite the 850 temps being shown on the models. And with MRX uncharacteristically jumping on this ahead of time, I'm getting rather optimistic.

here comes the winter storm watches back to our west, starting to cover western part of arkie,

Hpc probs of snowfall greater than one inch



Hpc probs of ice accumulation of greater than a tenth of an inch

So basically were looking at a statewide 1/2inch to 1inch changing over to all rain event? Meh Imo I'll take it this winter but any other winter this wouldn't be good enough for me.

if we just can hold off that warm tongue long as we can, really think we can do pretty good with snow n sleet accumulations, i like the nam gfs trends.

I don't think we can really predict accumulations at this point, but it looks to me like there is potential here to go above an inch. With convective enhancement as MRX mentioned, some areas could get lucky.

I hope. I would be happy with 1inch if it didnt melt 1hr later but in this case I want a good heavy snow that drops several inches. 1-3inches would be good if I was on the higher end. Guess this event is more of a wait and see kind of event that could go any different way. Well thats good atleast theres a chance for something big.

Yeah its a little early for accums in such a close situation. This a southern stream system and big fat silver dollars will be colliding with the ground somewhere. As mentioned above by DW... dry air could very well be a problem...especially in northern locales...but I imagine somebody UNELEVATED will get well over an inch..Hard to say who that someone is at this point though.

Toot wrote:Yeah its a little early for accums in such a close situation. This a southern stream system and big fat silver dollars will be colliding with the ground somewhere. As mentioned above by DW... dry air could very well be a problem...especially in northern locales...but I imagine somebody UNELEVATED will get well over an inch..Hard to say who that someone is at this point though.

the dry aire shouldnt poise a problem very long, the quality of the qpf should saturate the columns fairly quickly, meg mentioned this earler today.

From what I can tell it looks like my area could be in a good spot for those fat flakes Toot was referencing. It will be borderline but when everything is marginal in Chatty and we do get snow it's usually those big ass flakes.

Im guessing we get heavy snow for a few hours before transitioning to all rain. Looks like 1 or 2 inches possible before it quickly melts away. The sad thing is if snow does fall at night I won't be able to see it since I go on nights the next 2 weeks starting Monday. Oh well, maybe I'll get lucky if it does snow it will hold off until 5am.

Toot wrote:OHX

SOME INTERESTING THINGS NOTED...THE LATEST NAM MODEL IS COLDER
THAN OTHERS...INDICATING A PERIOD OF ALL SNOW ACROSS THE AREA
BEFORE A LATE NIGHT TRANSITION TOWARD LIQUID. THIS WOULD SUGGEST A
GREATER SNOW ACCUMULATION POTENTIAL. ALSO...A DEVELOPING WARM NOSE
WITH COLD AIR ALOFT (NEAR -25 DEG C 500 MB) WILL CREATE STEEP MID
LEVEL LAPSE RATES. FORECAST SOUNDINGS SHOW TOTAL TOTALS INDICES
CLIMBING INTO THE LOW TO MID 50S. THIS COULD LEAD TO SOME
CONVECTIVE ENHANCEMENT OF PRECIPITATION...PERHAPS SOME LOCALLY
ENHANCED BURSTS OF SNOW OR SLEET WHICH COULD MAKE THINGS
INTERESTING...AND MORE DIFFICULT TO FORECAST.

man it sure looks like jmundie got ohx attention...

I totally misread when Toot posted that, I thought that discussion was from MRX lol.

I appear to be sitting in a north of 40 dry slot for the snow. Oh well, good luck to those south of here!

The wrf model looks ugly now.

Morning all. Noticed the 6z Nam and GFS were not as good as the run before. NAM still had a couple of inches for the plateau. Any ideas on whether or not this might be a Nowcast system? Hope so. Looking for a little extra! OHX had me at 70% sleet/snow mix for monday night. Now they changed it to 60% rain/snow. I also noticed that NW TN is under a winter Storm Watch. 12 degrees this morning! Anyone know the LINK for the African Weather Man Blog

The potential is still there for something fun but yeah the modeling isn't quite as good this morning.