Surface cyclogenesis and heavy snowfall across northern

Utah on December 25-27 2003

 

 

 

Storm totals (inches) from Thursday December 25 through Saturday morning December 27 2003

 

Northern Valleys       Mountains

East Layton

30.0

Snowbird

60.5

Bountiful

28.0

Alta UDOT

55.0

Upper Mill Creek

27.5

Snowbasin

45.0

Tooele

24.0

Solitude

43.0

Centerville

23.0

Spruces

41.0

Sandy Bench

22.0

Silver Lake

37.0

South Ogden

22.0

Sundance

29.0

Northeast Ogden Bench

20.5

Brian Head

27.0

North Salt Lake

20.0

Trial Lake

24.0

Clearfield

18.4

Nordic Valley

22.0

Taylorsville

16.0

Mammoth

18.0

Holladay

16.0

 

 

Rush Valley

15.0

Mountain Valleys

 

Salt Lake Airport

14.8

Park City

11.0

Santaquin

14.0

Laketown

10.0

Smithfield

14.0

Meadow

8.0

Payson

13.0

Randoph

8.2

Spanish Fork

13.0

Heber City

8.0

Logan

13.0

Duchesne

11.0

 

 

Surface analyses

 

LAPS analyses from 0900 to 2300 UTC 25 December 2003.  Isobars are contoured every 1 mb.

 

 

MSAS analysis from 1200 to 2000 UTC 25 December 2003. Pressure falls are blue in the image.

Isobars are contoured every 2 mb.

 

MSAS analysis at 0400 UTC 26 December 2003. Pressure falls are blue in the image.  Isobars are

contoured every 1 mb.  Green dashed lines are 3-h pressure change in mb.

 

 

Upper air data

 

KSLC sounding at 0000 UTC 26 December 2003.  Note the deep layer saturation in the -10 to -20C

Temperatures (between blue lines).  This is the maximum dentritic snow growth zone.

 

KSLC sounding at 1200 UTC 26 December 2003. 

 

 

Satellite imagery

 

GOES-10 water vapor imagery from 0100 to 2300 UTC 25 December 2003.

 

GOES-10 infrared imagery 0530 to 2330 UTC 25 December 2003.

 

GOES-10 visible imagery from 2100 to 2300 UTC 25 December 2003.

 

 

Radar loops

 

Radar composite reflectivity mosaic from 2100 to 2336 UTC 25 December 2003.  I was driving

through Little Cottonwood Canyon and it was snowing hard with large snow flakes between 2300

and 0000 UTC.

 

Radar composite reflectivity mosaic loop from 0000 UTC to 2300 UTC 26 December 2003 with LAPS

surface MSL pressure.  An AWIPS outage caused missing data.

 

 

Model data

 

4-panel display of Eta80, Eta20, GFS80 and NGM80 surface MSL, wind and QPF grids

(clockwise) from the 1200 and 1800 UTC 25 December runs.   Time matching

in AWIPS was set to display the most recent run.

 

4-panel display of Eta80, Eta20, GFS80 and NGM80 grids for 700-mb humidity,

temperature, and wind (clockwise) from the 1200 and 1800 UTC 25 December

runs.  Time matching in AWIPS was set to display the most recent model run.

 

1200 UTC 25 December 2003 Eta run total QPF ending at 0000 UTC 28 December.

 

1200 UTC 25 December 2003 GFS run total QPF ending at 0000 UTC 28 December 2003.

 

1200 UTC 26 December 2003 Eta run total QPF ending at 0000 UTC 28 December.  Note the maximum

of 2.23 in in eastern Salt Lake County along the southern Wasatch Range.

 

1200 UTC 26 December 2003 GFS run total QPF ending at 0000 UTC 28 December 2003.

 

1200 UTC 25 December GFS run on 4-panel display depicting cyclogenesis over northeast Utah

at 1200 UTC 26 December 2003.  Clockwise from upper left includes 500-mb geopotential height,

voriticity, wind and temperature, then surface MSL pressure, wind, QPF, 1000 to 500-mb thickness,

and lower left includes 250-mb wind speed and wind bards with divergence overlaid, and the

lower right panel displays 700-mb geopotential height, humidity, wind and temperature.

 

 

PRODUCT TIMELINE

 

Note: Zone 3 is the Salt Lake Valley and Tooele Valley

Zone 8 is the southern Wasatch Range (Cottonwoods included)

Other forecast zones were included during this event

 

Storm went from Thursday December 25 to Saturday December 27

 

The National Weather Service has issued:

 

 

700 am Tuesday December 23 2003            HWOSLC Hazardous Weather Outlook for significant snow accumulations possible

 

345 pm Tuesday December 23 2003            WSWSLC- Winter Storm Watch zones 3 and 8 for 6 inches by late Christmas

 

400 pm  Tuesday December 23 2003           HWOSLC updated for Watch

 

600 am Wednesday December 24 2003      WSWSLC- Winter Storm Watch for zone 3 for 4-10 inches by late

Christmas and Winter Storm Warning for zone 8 (southern Wasatch Range)

HWOSLC- Hazardous Weather Outlook with “major winter storm” discussion

 

400 pm Wednesday December 24 2003     WSWSLC – Winter Storm Watch for zone 3 (Warning remained in zone 8)

                                                                                2-6 inches by late Christmas afternoon for zone 3

                                                                                5-10 inches Thursday night to Friday for zone 3

400 am Thursday December 25 2003

 

ZFPSLC (Zone forecast)                                    WSWSLC- Winter Storm Warning for zone 3

 

Zone 3                                                                   5-12 inches total north of SLC

Period 1                 1-3 inches                             6-14 inches total south of SLC

Period 2                 3-6

Period 3                 2-4

6-13 total

Zone 8                                                                   2-3 feet

Period 1                 5-10

Period 2                 5-10

Period 3                 5-10

15-30

 

300 pm Thursday December 25 2003

 

ZFPSLC                                                                 WSWSLC- warning

                                                                               

Zone 3                                                                   5-12 inches north of SLC (6-14 inches south of SLC)

Period 1                 1-3 (3-6 benches)                              

Period 2                 3-6

Period 3                 50 percent chance

4-9 (6-12 benches)

Zone 8                  

Period 1                 6-12                                        2-3 feet

Period 2                 6-12

Period 3                 3-6

15-30

 

500 am Friday December 26 2003

 

ZFPSLC                                                                 WSWSLC-warning

                                                                               

Zone 3                                                                   6-14 inches

Period 1                 3-6                                         

Period 2                 50 percent change

Period 3                 50 percent chance

3-6

Zone 8

Period 1                 8-14                                        30-40 inches

Period 2                 3-6

Period 3                 50 percent chance

11-20

 

10 am Friday December 26 2003

 

ZFPSLC                                                                 WSWSLC-warning

                                                                               

Zone 3                                                                   12-20 inches by Friday night

Period 1                 4-8                                         

Period 2                 2-4 (locally higher)

Period 3                 50 percent chance

3-6

Zone 8

Period 1                 10-16                                     35-50 inches

Period 2                 8-14

Period 3                 50 percent chance

11-20