2/24-2/26 Snow (Ring the doorbell so the big dog wakes up!!!)

[bud2380]

6z GFS is gonna make Hawkeye happy (and me obviously). Really good hit. Looks a lot like 3K NAM

[bud2380]

14” for CR. 17” for Dubuque

[Tom]

Talk about model volatility with this system.  Its just been the story all season long.  I think a lot of has to do with the unusually strong AO this year and the models must be digesting the data and incorporating it in a way that offsets them.  Haven't been able to post much since yesterday morning but back in the saddle this morning.  Got a Baptism to go to later today so I'll be out of pocket till later.

 

Meantime, the 00z Euro puts Chicago and most of N IL/NW IN/S MI back in the game....

 

 

[Grizzcoat]

DMX now talking heavier snows.... Wow. Never thought that. I give up. The model volatility with this event is absurd and shows how much you can't trust ANYTHING.

 

As the upper level wave continues to fill and the surface low
northeast late Monday, the northern stream wave/deepening closed low
will begin to slide in from the northwest and attempt to phase with
the remnants of the exiting wave. This is where the details are
hazy. GEFS members and available Euro ensemble members continue to
depict a fairly wide range of solutions with the various phasing
possibilities. As an example, the 12z Euro and 00z GFS interplay
results in a Fujiwhara type effect with the surface low pulling it
back west slightly, which would linger precip over portions of
central/eastern Iowa longer while the 00z Euro is further east and
slower in the overtaking of the exiting wave and surface low.
Even so, it does appear at least eastern Iowa is in line for the
potential for winter headline snowfall Tuesday into early
Wednesday. The greatest uncertainty lies as you move westward into
central Iowa with the various tracks/solutions and a likely
fairly sharp cutoff wherever the deformation zone develops. As it
currently stands, forecasts have risen significantly, with as much
as around 5 to 6 inches in the forecast for Des Moines and Ames
areas and up to around 10 inches as you move east toward Cedar
Rapids and Dubuque.

[Tom]

06z NAM...wow, what a perfect pivot for IA/N IL folks....

 

 

 

 

06z NAM 3km...

 

[Grizzcoat]

When will this energy be properly sampled? For sure has not at this point?

[Tom]

00z EPS/Control...my, oh my, what a pretty map for the Chi...the EPS keeps getting juiced each run...gotta thank that Hudson Bay Block and what has been a season of missed opportunities, could this be the one that breaks that trend???  Gosh, I certainly hope so because time is running out before Spring settles in and we enter the time of year of "wasted cold".

 

 

 

 

 

[Tom]

When will this energy be properly sampled? For sure has not at this point?

It's been sampled already by now...energy made it onshore after 18z runs yesterday...see map below...ULL makin' its way into So Cal right around Noon yesterday.  Prob why we are seeing the shifts SE per the latest runs.  It could very well come back NW if the storm trends stronger.  This evenings 00z runs should tell the story IMO bc the lead wave will be developing east of the Rockies right around 00z tonight.

 

 

[Tom]

06z GFS....

 

[Tom]

I haven't read an AFD discussion from LOT like this all season long...

 

 

 

The deepening closed upper low then continues to move slowly east
into the western Great Lakes region Tuesday through Wednesday,
with surface low pressure tracking from far southern IL early
Tuesday morning northeastward toward lower Michigan by Wednesday
evening. This slower and farther north track of the surface low is
not surprising given the wrapped-up nature of the deepening upper
low, though spread remains in the model track solutions during
this period and further shifts are probable until guidance
converges on a common solution. Setting aside track differences,
it does appear that the potential for fairly strong forcing will
develop during the Tuesday night through Wednesday period, with
upper diffluence/left exit region divergence atop a developing
easterly warm advection trowal setup in addition to fairly steep
mid-level lapse rates of 6 to 7 C/km. Dynamic cooling of the
column, and deepening low level cold advection on increasing
north-northeast low level winds would result in a changeover to
snow from northwest to southeast across the forecast Tuesday
night, with the potential for significant accumulating snow across
portions of the cwa. Gusty 20-30 mph northerly winds would also
potentially produce impacts of blowing and drifting snow. However,
significant differences remain between models with the exact
track of the system. This greatly affects the placement of the
heaviest snow across the region, from IA-WI and far northwest IL
from the farther north GFS, to a more direct impact from the
farther south ECMWF and CMC. Given the complexity of the
developing system and the potential for further model track
adjustments, forecasting explicit snow amounts remains difficult
at this time. The basic message however is that the potential
exists for a significant snowfall of inches is possible across
especially northern parts of the forecast area mid-week.

[Tom]

06z GEFS...SE trend???

 

 

[GDR]

Everybody ready for another shift today! Let’s get ready to rumble!

[dubuque473]

First time in 3 years I will have to refill my 2-Stage.

[stratosjeff]

Everybody ready for another shift today! Let’s get ready to rumble!

So now it's not missing us?

[Tom]

RPM model looks real good for E IA/N IL and into SE WI...

[Hawkeye]

When will this energy be properly sampled? For sure has not at this point?

 

The second wave will be sampled later today.  The 00z runs will have that data.

[Hawkeye]

Iowa cannot afford a delayed phase of the two waves.

[GDR]

Man another shift se will take dsm out of anything with the nam

[OKwx2k4]

Looks cool enough to annoy and dust me a bit down here.

[Money]

12z NAM continues the SE trend

[Tom]

18z Euro...primarily all snow from I-80 on north in N IL...quite the wet storm shaping up...RPM looked similar to this run and painted over 1.30"qpf for Chicago.

[GDR]

Nam looks good for eastern iowa

[Madtown]

lol should have known th SE trend would continue

[Money]

Actually looks more NW than 6z at HR 51

[GDR]

Nam definitely Southeast

[Tom]

12z NAM throwing out some lolipop totals for N IL thru Noon on Tuesday...

[GDR]

In Iowa

[Money]

Looks like 6-8:1 type ratios in Chicago

[Madtown]

oops was looking at 6z

[Tom]

12z NAM...ORD literally in the jackpot...first run of the season to show such a beauty...hope the trend continues...

 

[bud2380]

NAM still looks great for Iowa city and CR. Looks similar in placement as the 00z run. Just with more reasonable snow totals. 10”+? Yes please.

[bud2380]

3k NAM with basically a foot of snow for Iowa city and the storm isn’t even done yet at the end of the run

[Madtown]

[GDR]

[Hawkeye]

So the 12k NAM shifted nw, but the 3k NAM shifted east.

 

If the lead wave was just 3-6 hours slower, Iowa would be clobbered (not just eastern).

[Hawkeye]

12z ICON is not budging from its southeast track.

[Hawkeye]

The RGEM looks like the ICON.

 

We still have a few models on our side, but I just don't feel good about this.

[Money]

Icon shifted NW from 6z

[Madtown]

not too worried about the rgem and icon at this point...most winters we wouldnt even think about them.

[Hawkeye]

The waves appear a bit farther apart on the 12z GFS, so it should be at least a bit southeast.