March 23rd/24th snow - Working towards average by May!

[St Paul Storm]

Interesting cross section from tropicaltidbits visualizing exactly what is at fault for the extreme cutoff on the NE edge.

 

That’s good stuff right there. Thanks for posting this.

[james1976]

Biggest storm of the season and ill be out of state.

#Pissed

[Minny_Weather]

http://www.spc.noaa.gov/products/outlook/day2otlk_1730.gif?1521775589746

 

Marginal risk issued. Let's hope nothing severe actually does happen as I'll be in Texas and missing it.

[Hawkeye]

00z ICON and RGEM both shifted south.  Neither of them gets any precip past Dubuque.

[bud2380]

GFS looks solid

[bud2380]

Oh RGEM just with 17” for Iowa City. NBD

[Minny_Weather]

This has been an absolutely brutal Winter for cutoffs. I feel for the CR and Twin Cities people on here cuz we had the exact same issue in Lincoln all throughout January and February and we always got the sore end of the deal. Hope this works out for you all!

[Hawkeye]

CR folks have to like the trend from the evening models.

[Iowawx]

CR folks have to like the trend from the evening models.

What is your guess for CR snow total? I’m going towards lower end of things and I think 3-4 seems likely.

[bud2380]

Canadian blasts CR as well

[Hawkeye]

What is your guess for CR snow total? I’m going towards lower end of things and I think 3-4 seems likely.

 

I've been saying a sloppy 1-2", but if the UK and Euro come in the same or sw I may have to up it.  Our area is right on the line, so a degree or two difference in column temp would be a big deal.

[bud2380]

I think 3-6” for Johnson county. Maybe 5-8” for Linn. With this heavy wet snow it can take awhile to accumulate bit of snow rates are as high as indicated it will start to pile up. And the heaviest snow should fall in the AM hours which gives a better chance to stick.

[Hawkeye]

00z UK, only slight changes.... a bit wetter overall, west end of band a bit south, east end a bit north, no change in Iowa.

 

[james1976]

Hard to ignore runs this evening. Looking forward to morning AFD's. I imagine most of E IA will be upgraded to Warning. Maybe some of these higher totals will verify after all.
​30+ wind gusts are gonna plaster snow to everything.

[Hawkeye]

00z Euro coming in even farther sw.

[Hawkeye]

Wow, Dubuque gets nothing this run.

[bud2380]

Wow. I’d say. Significant jump SW. Iowa City and CR right in the cross hairs now. This is such a narrow band though.

[Hawkeye]

00z euro..... wow, big jump sw, also stronger/wetter.  I didn't think I'd have to get nervous about it trending too far sw.  We still have a day of possible changes to go.  I mean, Dubuque just went from 0.8" of precip to zero in one run.

 

[Craig-OmahaWX]

00z euro..... wow, big jump sw, also stronger/wetter.  I didn't think I'd have to get nervous about it trending too far sw.  We still have a day of possible changes to go.  I mean, Dubuque just went from 0.8" of precip to zero in one run.

 

ecmwf_acc_snow_iowa_48.png

lol give it a days worth of model runs and this baby will be in eastern neb before we know it! 

[Hawkeye]

00z Euro ensemble mean also jumped sw.

 

[bud2380]

NWS issued a winter weather advisory for my county despite the euro showing 14”. Frankly I think I’ll be upgraded later. For Cedar Rapids they issued a winter storm warning calling for 6-10” with isolated 15”. Local news channel just said 3-6”

[Tom]

If this system hit during the winter months, I'll be honest, it would hurt but given it is Spring I'll be just fine.  Glad to see our E IA friends about to get smashed by a winter storm.  I like DVN's write up and confirm the fact that Thundersnow is a good bet...Cantore, where are you???  Looks like they upped totals to 6-12"+ in spots.

 

 

 

.LONG TERM...(Tonight through Thursday)
ISSUED AT 315 AM CDT Fri Mar 23 2018

Extremely dynamic, strong, early spring winter storm, a very
challenging forecast tonight and Saturday with heavy snow a
certainty with exact locations still an issue.

Long Term Forecast Assessment...average to below average with near
to below average confidence due to very strong evaporative cooling
expected to occur with this storm. This will likely make many
locations snow totals off by 3 plus inches depending on snow
changeover. Thunder-snow very likely with accumulation rates well
over an inch an hour at times. Heavy snowfall rates will also result
on snow covered and slushy roads with risk of heavier snow access
maybe 30 plus miles further south for later shift to reassess.

Tonight...bands of rain to mix with and change to snow over most of
the northern 1/2 or more of the region in the evening hours. As
mentioned above, the locations for heavy snow will be a major
challenge with large dendritic growth in strong forcing and thunder-
snow almost guaranteed up to I-80 suggested. Half dollar sized
flakes will be common with snowfall accumulation rates of a half
inch to well over an inch an hour. Locations along and north of
I-80 should have mostly 2 to 7 inches of snow by daybreak with
east winds of 20 to 30+ mph. Limited blowing snow suggested due to
low snow ratios of 7 to 10 to 1. Mins tonight around 30F north to
upper 30s far south.

Saturday...Snow line to slide further south with evaporative cooling
continued heavy snow rates and again risk of thunder-snow into late
morning hours. Additional snow totals of 2 to 6 inches suggested,
mostly before 3 PM. Again gusty easterly winds of 20 to 30+ mph and
some drifting of heavy wet snow to be likely with roads poor due to
intense snowfall rates of slush and snow. Very possible the highway
34 corridor in Iowa and south may need at least an advisory for
later shifts to monitor. Highs will be in the mid to upper 30s with
roads likely improving with diminishing snow by late afternoon.
Forcing tools suggest widespread 6 to 12 inches of snow in warning
locations with isolated 12 plus inches a real possibility. The
heaviest snow axis is currently suggested to be between
Independence Iowa to Clinton Iowa to Princeton but local forcing
tools again with strong evaporative cooling suggest this axis
could move further south by 30 miles or maybe even more.

[bud2380]

It’s stil American models vs. the world. Gfs and nam remain much futher northeast than Canadian Euro and UK

[bud2380]

At least the NWS acknowledges they may need to shift the forecast further south

[bud2380]

6z CMC just blasts my area.

 

[Tom]

6z CMC just blasts my area.

 

FDF6D2D9-5B45-4A36-8C7B-4AC45F94D43E.jpeg

I like where you sit Bud, as well as, Haweye and the rest of you in E IA.  Finally, the IA "Low Magnet" is delivering the goods...

[St Paul Storm]

I’m glad this is going to miss by more than one county. Grids down to less than 0.5” of snow.

 

Good luck Iowa peeps!

[james1976]

Euro with over a foot for me. Just wow

[hlcater]

Holy cow the overnight model runs are extremely juiced and DVN has me pegged at 10?!?! inches. It’s becomjng apparent that whoever is under that band is going to get absolutely ripped on.

[bud2380]

The NAM finally joining the party and moving the southern edge further south.  It's still further north than the Euro, Canadian, and UK, but better than the 6z and 00z runs.  

[Tom]

E IA crush job in the works...I could see records being broken...why not???  Some spots will catapult towards seasonal norms if those higher totals do in fact materialize.

[bud2380]

NAm shows 1.7" qpf for Iowa City and 13" of snow.  The largest storm I have recorded since I moved to North Liberty in 2004 was 12", which happened two or three times (i'd have to check my records).  So if we got 13" it would be a new record for me.

 

 

http://maps1.pivotalweather.com/maps/models/nam/2018032312/033/snku_acc.us_mw.png

[Tom]

Thundersnow signal baby...this will be a solid 12-14+ hour snow event with 1-2"/hr snowfall rates one can come to a conclusion that those 8-10"+ totals are looking like a good bet.

 

[Hawkeye]

12z HRRRx coming in south as well.

[bud2380]

The regular HRRR has a bullseye over Iowa City already.   

 

 

 

http://maps2.pivotalweather.com/maps/models/hrrr/2018032313/017/snku_acc.us_mw.png

[Hawkeye]

I can't find a total precip/snowfall map for the HRRRx, but the 12z loop on Tropical Tidbits is perfect for Cedar Rapids.

[Jaycee]

Gosh, if we had some warm air to work with I feel like this would be a major severe wx producer over here. Too bad we're not supposed to reach 60 today. Oh well, HRRR shows some good spring thunderstorms tonight moving through, can't complain about that!

[bud2380]

RGEM is looking good through 21 hours so far on Pivotal.  

[Iowawx]

The last time we had a decent March snowstorm was March 28, 2009. I don’t remember how much snow I got from that but most of it melted the next day.

[bud2380]

Good lord, RGEM....

 

 

http://maps3.pivotalweather.com/maps/models/rdps/2018032312/039/snku_acc.us_mw.png