3/22 - 3/23 Spring Clipper

[Geos]

I've been measuring on my deck and it has compacted about 1.0"-1.25".  The measurements some are taking I think were done on cement/street levels that allowed more melting.  My current snow depth is 5.5".

 

Thanks.

I think I'll go with 3.8" here. With 0.29" of water that would be a 12:1 ratio. One thing that is challenging with spring snows, is if your not home to measure right away during the day when it stops - it's hard to figure out the actual total later.

 

This snow put my average above normal now for the season. Impressive from the December and early January we had.

[WildWisconsinWeather]

Actually majority of people did including you.

 

What are you thinking for tomorrow night's system Money?  This winter has been filled with disappointments here, so I'm ready for spring weather for good, but of course that won't happen, will it?

[Money]

What are you thinking for tomorrow night's system Money?  This winter has been filled with disappointments here, so I'm ready for spring weather for good, but of course that won't happen, will it?

 

Meh. i haven't even looked at the models for at least couple days. Just saw it mentioned in the AFD tonight. I'll wait and see what 0z runs show. 

[Tom]

Nice write-up regarding this late season snow event....

 

Snowfall Totals

 

Preliminary Snowfall Map

http://www.crh.noaa.gov/images/lot/15mar23/prelimsf.jpg

Map based on Local Storm Reports

 

 

 

Meteorology

Some of the key meteorological takeaways of this event:

• The timing of this event was key to impacts, in that it came during the morning commute time, including in the Rockford and Chicago metro areas. 
• Snowfall rates of 1-2" per hour were common during Monday morning and spread across a larger area than is typically seen with a Pacific/Clipper-hybrid system.  Normally such rates with these systems archetypes are in focused bands.
• High moisture (3-4 g/kg) was steered into the precipitation forcing region of this system.  In other words, ample moisture was ingested and the forcing for lift was strong enough to wipe out the dry low-level air mass ahead of the snow.
• The thermal profile aloft was unstable enough to warrant some thundersnow to the northwest of the area.  Even though thundersnow did not occur in our area, the thermal profile aloft was quite unstable per observation and analysis and thus resulted in stronger areas of rising air and quicker precipitation development and increased rates.
• Typically with early or late season events where the atmosphere is milder than during the heart of winter, snow-to-liquid ratios can be quite low...or in other words, the "efficiency" of the atmosphere to produce snowfall from the same amount of liquid diminishes.  While low ratios were indeed observed, the vertical temperature and moisture profiles ended up being ideal for snow aggregation, where flakes "clump" together as they fall, leading to larger flakes reaching the surface producing quicker and larger accumulations. 

 

Water Vapor Satellite Loop on 3/23/15: 2 am - 12 pm

http://www.crh.noaa.gov/images/lot/15mar23/15mar23wv.gif

This satellite loop shows the pronounced upper level wave and its areas of rapid saturation in advance, where the heaviest of snow was being observed under. 

 

 

Elevated Lapse Rates (Instability) on 3/23/15:  7 a.m.

850mb Warm Advection (Milder Air Advancing and Lifting) on 3/23/15:  10 a.m.

http://www.crh.noaa.gov/images/lot/15mar23/lapserates.jpg

http://www.crh.noaa.gov/images/lot/15mar23/waa.jpg

 

 

NWS Chicago 0.5° Radar Image from 3/23/15:  8:30 a.m.

http://www.crh.noaa.gov/images/lot/15mar23/15mar23radar1.jpg

 

 

http://www.crh.noaa.gov/images/lot/15mar23/15mar23xsect1.jpg

http://www.crh.noaa.gov/images/lot/15mar23/15mar23xsect2.jpg

 

 

 

Late Season Snow Climatology

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
242 PM CDT MON MAR 23 2015

...LARGEST CALENDAR DAY SNOW AFTER THE SPRING EQUINOX SINCE 1982...

BOTH ROCKFORD AND CHICAGO OHARE AIRPORTS TODAY...MARCH 23RD...
RECEIVED OVER FIVE INCHES OF SNOW. THIS WAS THEIR HIGHEST CALENDAR
DAY SNOW AFTER MARCH 21ST SINCE 1982. PLEASE SEE THE FOLLOWING
TABLES TO SEE WHERE THE SNOW RANKED WHEN COMPARED TO ALL OTHER POST
SPRING EQUINOX SNOWFALLS OF FIVE INCHES OR MORE:

...CHICAGO...

RANK VALUE DATE
1 13.6 MARCH 25 1930
2 9.4 APRIL 5 1982
- 9.4 APRIL 2 1975
4 9.0 APRIL 6 1938
5 8.9 MARCH 26 1970
6 8.2 APRIL 1 1970
7 7.8 MARCH 30 1926
8 7.7 MARCH 29 1954
9 7.1 MARCH 29 1964
10 6.6 MARCH 26 1934
11 6.5 MARCH 29 1972
12 6.4 APRIL 4 1920
13 5.6 MARCH 23 2015
- 5.6 MARCH 26 1930
15 5.4 MARCH 25 1970
- 5.4 MARCH 23 1965
- 5.4 APRIL 16 1961
18 5.3 MARCH 28 1894

THE TOTAL SNOWFALL FOR THIS MOST RECENT EVENT WAS 5.8
INCHES WITH 0.2 OF THAT HAVING FELL ON MARCH 22ND AND THUS NOT
INCLUDED IN THE TABLE ABOVE.


...ROCKFORD...

RANK VALUE DATE
1 13.5 MARCH 31 1926
2 12.0 MARCH 23 1897
3 10.4 MARCH 29 1972
4 7.0 APRIL 18 1912
5 6.3 APRIL 5 1982
6 6.0 APRIL 6 1938
- 6.0 MARCH 25 1933
8 5.1 MARCH 23 2015
9 5.0 MARCH 29 1954
- 5.0 MARCH 25 1933

$

JEE

[Money]

What are you thinking for tomorrow night's system Money?  This winter has been filled with disappointments here, so I'm ready for spring weather for good, but of course that won't happen, will it?

 

18z GFS had 0.7 QPF in MKE with mostly rain (temps between 32.5-33.5 degrees)

 

18z NAM was a bit warmer. 

 

 

18z GFS had about 7 inches of snow in LSE and near gosaints area 

[WildWisconsinWeather]

18z GFS had 0.7 QPF in MKE with mostly rain (temps between 32.5-33.5 degrees)

 

18z NAM was a bit warmer. 

 

 

18z GFS had about 7 inches of snow in LSE and near gosaints area 

 

Yeah, I'm not expecting anything here, more excited about isolated thunder prospects than anything wintry tbh.

[FV-Mike]

Nice graphic from Skilling showing how unusual the storm was yesterday. Great to get one last push of snow!