Winter 2020/2021 Short Range Discussion

[hawkeye_wx]

7 minutes ago, cyclone77 said:

Very nice.  With as much as the precip areas keep dancing around from run to run makes me think many of us could be in for some surprises over the next 48hrs.

Absolutely.  Other models still have a dry hole over east-central IA.  This is a very interesting, rare system.  We aren't going to know where some of the heavier pockets set up until the upper energy finds its exact spin-up location.  The latest Euro spins it up pretty tightly over the Quad Cities area.

[cyclone77]

1 minute ago, hawkeye_wx said:

Absolutely.  Other models still have a dry hole over east-central IA.  This is a very interesting, rare system.  We aren't going to know where some of the heavier pockets set up until the upper energy finds its exact spin-up location.

Yeah the UK for example has danced back and forth west/east run to run.  Gonna have to see how everything evolves tomorrow for sure.  I guess by tomorrow I mean today now that it's shortly after midnight lol.  It's a situation where it's way too early to celebrate if your favorite model shows you getting dumped on, but also too early to be in despair if your area looks like it may get screwed.  This system is definitely interesting and exciting to track, but I'm def pining for a system that has a nice and wide swath of snow in spread-the-wealth style.  

[chuckster2012]

22 minutes ago, hawkeye_wx said:

Absolutely.  Other models still have a dry hole over east-central IA.  This is a very interesting, rare system.  We aren't going to know where some of the heavier pockets set up until the upper energy finds its exact spin-up location.  The latest Euro spins it up pretty tightly over the Quad Cities area.

Ha... .01" for me!

[Baum]

nowcast.

[A-L-E-K]

IA/MN winter

[Baum]

22 minutes ago, A-L-E-K said:

IA/MN winter

agreed.

 ...BLIZZARD WARNING IN EFFECT FROM 6 PM THIS EVENING TO 6 PM CST  
FRIDAY...  
  
* WHAT...BLIZZARD CONDITIONS EXPECTED. TOTAL SNOW ACCUMULATIONS OF  
  5 TO 8 INCHES WITH WINDS GUSTING AS HIGH AS 40 MPH.  
  
* WHERE...CENTRAL IOWA.

[Cary67]

ORD should change airport code to DAB

[A-L-E-K]

moving on to the sunday afternoon duster

[mimillman]

38 minutes ago, A-L-E-K said:

IA/MN winter

Just ouch

[OrdIowPitMsp]

33 and light rain/drizzle here. 6-10” forecast later this afternoon and tonight. Certainly been a MN/IA winter so far. Might push 40” on the season after all is said and done with this system. 

[hawkeye_wx]

I'd like for the op Euro to be right, but it's mostly on its own.  Central IA into MN should get the bulk of the snow.  I'd be happy with 2-3".

[cyclone77]

Gonna be interesting to see how things evolve later.  Looks like precip explodes nearly overhead later this afternoon, so could see some decent rippage for a time.  Most of the models want to quickly lift that north and then northwestward out of here leaving us mostly in the "eye" of the system for a good 36hrs.  I think our best hope is if we can hang on to today's precip a little longer than the models currently show (except the Euro).  The Euro would indicate the potential for some overachieving if we can stay in the zone of precip development longer before the eye of the system moves in.  Still gonna go 1-2", but could end up higher if the Euro scenario plays out.

[mimillman]

4 minutes ago, cyclone77 said:

Gonna be interesting to see how things evolve later.  Looks like precip explodes nearly overhead later this afternoon, so could see some decent rippage for a time.  Most of the models want to quickly lift that north and then northwestward out of here leaving us mostly in the "eye" of the system for a good 36hrs.  I think our best hope is if we can hang on to today's precip a little longer than the models currently show (except the Euro).  The Euro would indicate the potential for some overachieving if we can stay in the zone of precip development longer before the eye of the system moves in.  Still gonna go 1-2", but could end up higher if the Euro scenario plays out.

You're good for 2-4"

[McHenrySnow]

Temperatures are really going to preclude good accumulation here. I was hoping for an inch, but I doubt it. 

[Hoosier]

Trashy antecedent.  Much of the precip later looks to be wasted on rain or inefficient snow in the LOT cwa, except maybe western areas.

[Cary67]

17 minutes ago, Hoosier said:

Trashy antecedent.  Much of the precip later looks to be wasted on rain or inefficient snow in the LOT cwa, except maybe western areas.

Story thus far of the winter

[WeatherMonger]

ILX mentioning potential for thundersnow, not expecting much accunulation, if any but would make for an even trade.

 

Quote

.LONG TERM...(Friday through Wednesday)
ISSUED AT 149 AM CST Thu Jan 14 2021

The snowfall forecast will remain tricky through Friday as the
surface low remains parked over the Quad Cities. Most locations
across the forecast area will receive less than 1" as the best
dynamics and thermodynamics for widespread snowfall remain too far
west. Meanwhile across central Illinois, numerous light snow
showers will develop between early Friday morning and Friday
afternoon. These snow showers will be cellular, exhibiting some
convective elements given the steep low-level lapse rates. While
most of these cellular snow showers will be light, it is possible
a couple of them could be heavy. The thermal profile beneath the
cold core of the upper-level low will exhibit appreciable amounts
of omega within a saturated DGZ at times. This could potentially
lead to very brief periods of white out conditions, but will only
last minutes rather than hours with these scattered cells moving
across the region at a fast clip.

Since the snowfall across central Illinois will be mesoscale-
driven instead of synoptically-driven, we strayed away from the
global snowfall solutions (NAM, GFS, CMC, and ECMWF). Instead, we
leaned toward the short- term HiRes models (HREF, HRRR, etc) to
paint the better solution for estimated snowfall for Friday. This
put most of the forecast area at an inch or less, with very isolated
1-3" totals throughout the region

 

[mimillman]

On 1/12/2021 at 6:51 AM, mimillman said:

Sold.

DAB+ call here

Looks like I'm going to bust high.

[Hoosier]

Even though it won't amount to much, will be kind of cool to watch the snow showers spinning around on radar tomorrow.  CAM/hi-res models have a pretty showery look.

[purduewx80]

26 minutes ago, WeatherMonger said:

ILX mentioning potential for thundersnow, not expecting much accunulation, if any but would make for an even trade.

 

 

I wouldn’t go that far. “Convection” does not mean lightning and thunder are always involved. The convective profile would need to favor cloud tops at or colder than -30C for sufficient charge separation, and there isn’t much evidence of that in current guidance. At least locally, cell motions do not look all that rapid. Steering flow is only 5-15KT, so I think some of these will end up producing surprise amounts tomorrow, especially near any enhanced surface convergence. Nowcasting will have to involve looking for local “heating”, upper level vort max support and any surface troughing, which is similar to what we look for when forecasting thunderstorms in the summer. 

[mimillman]

Regardless of how f***ing abysmal things may seem, this will still be a pleasantly wintry weekend for the subforum. Here here.

[Hoosier]

8 minutes ago, purduewx80 said:

I wouldn’t go that far. “Convection” does not mean lightning and thunder are always involved. The convective profile would need to favor cloud tops at or colder than -30C for sufficient charge separation, and there isn’t much evidence of that in current guidance. At least locally, cell motions do not look all that rapid. Steering flow is only 5-15KT, so I think some of these will end up producing surprise amounts tomorrow, especially near any enhanced surface convergence. Nowcasting will have to involve looking for local “heating”, upper level vort max support and any surface troughing, which is similar to what we look for when forecasting thunderstorms in the summer. 

Wish it were a bit colder at the surface tomorrow, but I imagine there will be some localized cooling underneath the heavier snow showers.

[RCNYILWX]

Yeah, things definitely went the other way for anything meaningful into this evening. All but the far NW burbs hard pressed to get any accums. As has already been discussed, tomorrow's snow showers could produce some nice bursts at times. Liking late tomorrow night into Sat AM for an inch or two on the backside of the upper low and Sunday currently looks favorable for up to a couple inches.

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[McHenrySnow]

5 minutes ago, RCNYILWX said:

Yeah, things definitely went the other way for anything meaningful into this evening. All but the far NW burbs hard pressed to get any accums. As has already been discussed, tomorrow's snow showers could produce some nice bursts at times. Liking late tomorrow night into Sat AM for an inch or two on the backside of the upper low and Sunday currently looks favorable for up to a couple inches.

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Yeah, this is a bust. Not a forecast bust, necessarily, just a bust in general. I don't expect anything worthwhile until tomorrow night, as you say and I won't hold my breath for that. 

Thankfully, I didn't expect much from this - regardless of what the 15z RAP showed yesterday.

 

[McHenrySnow]

[Baum]

I never really was thinking much today or tonight. Was more thinking the backside snowshowers/squalls just to make it look a bit more like mid winter. Hard to get to revved over a slushy inch not panning out. 

[WeatherMonger]

1 hour ago, purduewx80 said:

I wouldn’t go that far. “Convection” does not mean lightning and thunder are always involved. The convective profile would need to favor cloud tops at or colder than -30C for sufficient charge separation, and there isn’t much evidence of that in current guidance. At least locally, cell motions do not look all that rapid. Steering flow is only 5-15KT, so I think some of these will end up producing surprise amounts tomorrow, especially near any enhanced surface convergence. Nowcasting will have to involve looking for local “heating”, upper level vort max support and any surface troughing, which is similar to what we look for when forecasting thunderstorms in the summer. 

Gotcha, I'm an enthusiast rather than student. I seen "cellular" and c9nvective both in there to make that assumption. Win some and lose some

 

Thanks for the clarification.

[McHenrySnow]

I like what the 18z HRRR is showing for tomorrow night across NE IL. 

[Hoosier]

As was mentioned, relatively slow motion/pivoting nature could allow these to hang over a particular area for some time.  Will be interesting to see if this is going to rise to the bar of needing a snow squall warning.

[hawkeye_wx]

The more bullish model runs (Euro) for eastern Iowa were rubbish.  My area may get an inch or two before the low spins up and pulls the dry slot over eastern Iowa.