Interesting Winter Situation...

[Robert Dewey]

Just read the latest AFD from DTX, and they are mentioning the potential of accumulating snow. I had to check the models myself, since it's nearly 50F outside (feels warm though, LOL).

While I am getting sick of winter, I am always up for a good snowfall, especially if that's the only thing you can get this time of year.

Anyway, between 24 and 36 hours, it appears that a weak circulation will develop along a moderately strong baroclinic zone that's going to setup as a result of this current low pressure system. NAM/ETA 12Z shows 0.75 inches of QPF, along with the GFS, which is on the colder side of the system. Snow ratios won't bee too impressive, I'm thinking 10:1 at most, possibly a touch higher. The 12Z GEM model outputs a storm total of nearly 36mm - roughly 1.50 inches of QPF... Obviously, that's the odd man out. ETA snow algorithm actually outputs 10 to 15 inches of snow across a small portion of lower MI and southern Ontario... Not getting my hopes that high though...

What looks interesting, is that the QPF and orientation of the low make it appear as though it will be a convective snow band. I don't have my GEMPAK machine up, so I can't tell if there is any instabillity or CSI to realize this potential.

Anyway, big turn around from the previous models...

 

[Dan Cook]

Davenport's mentioning a winter storm for next weekend.

 

[George Tincher]

Originally posted by Dan Cook
Davenport's mentioning a winter storm for next weekend.

That would likely be that HUGE system that's in developing stages over the Pacific as we speak. It's supposed to be a enormous storm.

This one may be worth keeping an eye on. Depending on the track, it may bring both snow and severe weather.

 

[rdale]

Tomorrow's event seems to be more "model" than anything else... MOS temps near 50 while precip type outputs say up to 4" of snow! GRR is taking the cheap way out - calling for 1-4"!

 

[Robert Dewey]

Originally posted by rdale
Tomorrow's event seems to be more \"model\" than anything else... MOS temps near 50 while precip type outputs say up to 4\" of snow! GRR is taking the cheap way out - calling for 1-4\"!

Agreed! LOL...

Latest NAM and NGM have >0.75 QPF, with 850mb temperatures hovering just below 0C to -3C... I could see a mix of rain and snow for the first hour that precipitation starts, but given the dynamics progged (extreme vertical velocity), I believe the column would cool pretty good for a change over to all snow. These bands have been known to produce very heavy snowfall in short periods of time, over a very small area... So who will get what and how much is outta the question until it starts, and you can visualize on the radar where exactly any band will setup.

18Z models wern't too kind to a mesoscale snowstorm scenario as the 12Z and now 00Z runs...

 

[Robert Dewey]

Wow... Models keep beefing up the QPF... 24 hour QPF totals on the 06Z NAM are around 1.25 to 1.50 inches. Vertical velocity is beyond impressive with this system... Very very heavy precip rates - Most likely with thunder and lightning in some spots.

Precip type is certainly a problem. NAM has 850mb temps flirting with 0C at the onset of precipitation, and has been bringing this up slightly with each run. Very heavy precip rates would agrue for mostly snow, with only a brief period of rain at the beginning...

 

[rdale]

NWS called for up to 9" while my forecasts said 2" with some isolated spots up to 4" at worst... Ooops ;> They still are saying we'll get widespread 3-5" readings, and I'm thinking my 2" might have been overkill!

 

[Andrew Pritchard]

Today was one of the best days I've seen in a long time. Temps neared 70 this afternoon...and the sky was decorated with cumulus clouds, which I hadnt seen in months. However, things changed rapidly. Between 6-8 PM the winds shifted hard to the north, and we were hit by 2 or 3 small thunderstorms. Around 9...it changed over to sleet, and we are now currently getting some light snow. We just got about everything...warm temps/sunshine, thunderstorms, sleet, snow and high winds...in a 12 hour period.

 

[Robert Dewey]

Originally posted by rdale
NWS called for up to 9\" while my forecasts said 2\" with some isolated spots up to 4\" at worst... Ooops ;> They still are saying we'll get widespread 3-5\" readings, and I'm thinking my 2\" might have been overkill!

Yeah... I'm not seeing too much potential. Things looked decent last night, but the models kept up the warming trend. The warm and wet ground will really kill any potential accumulation as well...

 

[rdale]

We still aren't going to get anywhere near the widespread 1"+ QPF's from the NAM... GFS was closer but seemed to be ignored by everyone - it just didn't look realistic to have that extreme fgen occuring so rapidly with so much moisture in place. Always makes for a stressful day when I have to repeatedly go SO far against everyone else (my chief met was 4-8", competition was 3-7") but when it's all over I feel MUCH better than they all do ;>