2/4-5 Potential Wound-up Low

[Madtown]

wow....just read all the pinpoint forecasts around me...4-6" maybe 5-7". Downplaying because of past events this year?

[Hawkeye]

GFSv16.... lol... I'll take the under.

[Madtown]

Also as a side note, the birds and deer the last 3 days have been going nuts feeding around the clock not just at peak times.

[East Dubzz]

5 minutes ago, Hawkeye said:

GFSv16.... lol... I'll take the under.

Sweet. Lock it in.

[Grizzcoat]

The monday wave is going nuts...

[Stacsh]

2 minutes ago, Grizzcoat said:

The monday wave is going nuts...

wrong thread, but the GFS has heavy snow in Iowa with NEGATIVE 2M surfaces temperatures.  That would be epic.  Will not verify, but epic run so far.  

[Grizzcoat]

my bad...

 

[Grizzcoat]

too many waves--- if you miss out on this winter pulse, you've had it before- or don't remember. This is borderline epic in progs. Still needs to happen, but my goodness- the potential is unreal and its multiple runs of many models. SIT BACK and ENJOY-- That's all I got. Midnight tonight I will be all over this. CRash....

[bud2380]

DVN going against virtually all model guidance.  

 

[Tony]

Really good AFD by LOT and also mentioning possibility of thundersnow.

 

Full technical discussion...

Our powerhouse cold front is finally making an appearance in the
surface observations, with 35 to 45 mph northwest wind gusts noted
pushing across the Dakotas and into northwest Nebraska. This front
will surge into the region through Thursday afternoon and evening,
delivering sharply falling temperatures and a likely period of
fairly strong wind gusts.

The main focus here remains on the relatively brief window for
precipitation, developing across our I-39 corridor locales towards
mid-morning tomorrow, and spreading east by late-morning and
early-afternoon. The parent shortwave trough axis will be
gradually acquiring a neutral tilt as it approaches our longitude.
Quite the shift in the thermal profiles (towards a colder note)
over the last few days with an overall somewhat deeper system with
a developing 990s mb surface low through the day.

From a dynamics/kinematics perspective, this incoming system is
definitely checking quite a few boxes. With strong system-
preceding DCVA, plus robust upper divergence in the left exit
region of a cyclonically-arcing 130+ kt jet streak, it`s no
surprise to see layer Q-vector convergence maximized over our
region in the roughly noon-7 pm timeframe. This forcing will
arrive with the addition of another anomalously moist airmass,
characterized by PWATs pushing 0.6 to 0.7". One of the somewhat
concerning aspects (outside of the wind potential) is the presence
of impressively steep lapse rates. Cross sections through the
incoming baroclinic zone show a deeper-than-typical layer where
theta-e lapse rates trend towards 0 or even locally negative for a
time tomorrow afternoon. The NAM/NAMNEST which, admittedly have
their issues with what look like some contamination in regional
soundings, actually carve out pockets of MUCAPE in excess of 50
J/kg, and this is seen across the suite of afternoon guidance.
Given the brief overlap of strongest ascent during this period,
don`t think it`s overly outlandish to expect a brief window where
thundersnow is a possibility.

[East Dubzz]

Surprised they’re just not going with a blizzard warning over here.

[jaster220]

2 hours ago, East Dubzz said:

Surprised they’re just not going with a blizzard warning over here.

Prolly got a call from GRR

[OttumwaSnomow]

3 hours ago, Grizzcoat said:

too many waves--- if you miss out on this winter pulse, you've had it before- or don't remember. This is borderline epic in progs. Still needs to happen, but my goodness- the potential is unreal and its multiple runs of many models. SIT BACK and ENJOY-- That's all I got. Midnight tonight I will be all over this. CRash....

For sure.. Ive had 6 snow events here since Dec 28.. Now the rapid fire begins. Very reminiscent  of  2014!

[Hawkeye]

00z HRRR.... once again backed off the larger area of 4" in favor of a couple bands with a gap in between.

[St Paul Storm]

Rain/snow mix has started here. Temp 32F

[Hawkeye]

Holy cow, NAM!  This just seems like a major outlier that's unlikely to pan out.

[East Dubzz]

Lol NAM is a roller coaster.

[Hawkeye]

00z 3k NAM is doing something simliar.  The NAMs are almost an inverse (over Iowa) of the HRRR.  Where the HRRR has a dry band (Waterloo), the NAMs are very wet.

[Madtown]

18z GFS/EURO 0Z NAM AND 3KNAM showing 8-12" here. Only weather outlet forecasting 8-12" accuweather...that makes me a little nervous. But seriously wondering what the thought is on holding g amounts so low.

[CentralNebWeather]

 

[BMT]

Latest RAP

[BMT]

All the other 00z HiRes models show widespread 2-4" in Iowa and CR getting 4-8".  One looks very similar to the NAM.  

[Minny_Weather]

The freezing drizzle is pretty intense right now. Just got off work and the van I drove for work was caked in ice. Roads were also sketchy. Only good thing about this is that it'll put a crust on the snow that we have right now, which will limit blowing impacts.

[St Paul Storm]

Kinda liking the latest RAP and HRRR runs. Going to be a quick hitter up this way, but it might pound for a bit. Models showing a nice band over/near the metro. Just give me 1-2" of fresh powder. 

[Hawkeye]

00z RDPS - holding steady, no jackpot bands, just a general 3-4".

[Minny_Weather]

9 minutes ago, St Paul Storm said:

Kinda liking the latest RAP and HRRR runs. Going to be a quick hitter up this way, but it might pound for a bit. Models showing a nice band over/near the metro. Just give me 1-2" of fresh powder. 

Same, I'd like some fresh stuff to cover the exposed grass before I'm stuck below zero for 5-7 days.

[BMT]

5 minutes ago, Hawkeye said:

00z RDPS - holding steady, no jackpot bands, just a general 3-4".

The rdps doesn’t really have any rain to start either.  Shows snow the entire time.

[hlcater]

There is convective potential here with steep mid level lapse rates leading to some conditional instability, so a weenie band, or general high variance in snow amounts over short distances might be more prone to happen.

[Hawkeye]

00z GFS no deviation from its bullishness.

[bud2380]

GFS still shows 6-7” for Iowa city and CR. Makes the NWS 1-2” forecast seem suspect. 

[Hawkeye]

00z GFSv16 even more bullish than the op.

[Madtown]

Still looks solid....GRB dropped my accumulation 6" max...scratching my head

[BMT]

Liking our chances at 4” here.  

[East Dubzz]

Some great runs the night before the event. 

[james1976]

All I can say is if we get that much fresh snow on top of the current snowpack with the incoming winds..........Definitely blizzard. Could really get wild if all pans out. Really hope people take the headlines seriously.

[BMT]

Canadian coming in wetter for Iowa 

[Hawkeye]

1 minute ago, BMT said:

Canadian coming in wetter for Iowa 

Yes, the GDPS has added more of a jackpot zone in the same area as the NAMs/GFSs.

[BMT]

Anyone have the wind gust maps from the latest runs?  I don’t have access.  

[Hawkeye]

00z UK... this model is clearly not organizing the snow quite as early as the more bullish models.

[james1976]

DMX had a heck of an afternoon AFD. This quote pertains to Thursday:

The blowing snow will make some roadways
impassable. Motorist could become stranded on rural roadways and
with wind chills falling below zero, this could become a dangerous
situation.