Alert archive / Wyoming / Mesoscale Discussions in 2003

Mesoscale Discussion 36

February 1, 2003Fremont County, Sublette County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Feb 1, 2003, 9:37 PM MST for Fremont County, Sublette County, Wyoming. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Feb 1, 2003, 9:37 PM MST (04:37 UTC)
Expired: Feb 2, 2003, 4:30 AM MST
In force: 7 hr
Issued by: the Storm Prediction Center

Counties Fremont County, WY, Sublette County, WY

The radar

The Riverton/Lander radar (KRIW), 48 km from the middle of the area, began a volume at 04:42 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 4.6 hours before the alert went out and 51 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2182 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 173 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

417 
ACUS11 KWNS 020437
SWOMCD
SPC MCD 020437 
WYZ000-021130-

MESOSCALE DISCUSSION 0036
NWS STORM PREDICTION CENTER NORMAN OK
1037 PM CST SAT FEB 01 2003

AREAS AFFECTED...PORTIONS OF WRN/CENTRAL WY

CONCERNING...HEAVY SNOW 

VALID 020437Z - 021130Z

HEAVY SNOW WITH HOURLY RATES APPROACHING 2 INCHES WILL DEVELOP
BETWEEN 02/06Z AND 02/09Z OVER WRN INTO CENTRAL WY AND LAST
THROUGH AT LEAST 02/12Z. ACCUMULATIONS FROM 10-12 INCHES WILL BE
POSSIBLE THROUGH THIS TIME...ESPECIALLY IN NORTH FACING UPSLOPE
ENHANCED AREAS.



00Z UA ANALYSIS INDICATED A STRONG UPPER JET LOCATED OVER CA/SRN
NV /120 KTS/...WITH A SECONDARY NRN BRANCH JET OF 100-120 KTS
OVER THE ERN MT INTO NRN MN. STRONG UVM DUE TO POSITIONING OF
THESE TWO JETS ALONG WITH BROAD UPPER DIVERGENCE AHEAD OF GREAT
BASIN SHORTWAVE TROUGH WAS AIDING IN RAPID ENHANCE OF FRONTAL
PRECIPITATION BAND OVER SERN ID AND FAR NRN UT. AS UPPER TROUGH
CONTINUES TO PROGRESS EWD INTO ERN NV/WRN UT THROUGH 12Z...EXPECT
STRONGEST FORCING TO MOVE INTO WRN AND CENTRAL WY. RECENT SFC
ANALYSES INDICATE THAT MODEST PRESSURE RISES OVER NRN WY BEHIND 
ADVANCING COLD FRONT. COMBINATION OF INCREASING CAA OVER CENTRAL
AND EVENTUALLY SRN WY WITH FRONTAL PASSAGE WILL AID IN SNOW
LEVELS FALLING RAPIDLY TO THE VALLEY FLOORS. 15-25 KT NNELY WINDS
BEHIND THE FRONT WILL FAVOR OROGRAPHICAL ENHANCEMENT ALONG AND
JUST NORTH OF E-W ORIENTED MTNS...ESPECIALLY THE WIND RIVER AND
GRANITE MTN RANGES. ADDITIONALLY MID LEVEL
FRONTOGENESIS/DEVELOPING DEFORMATION ZONE AND 7-7.5 DEG C/KM
LAPSE RATES IN THE DENDRITIC SNOW GROWTH LAYER WILL AID IN
FURTHER MESOSCALE ENHANCEMENT AND CONVECTIVE SNOWBURST POTENTIAL.
THUS HOURLY ACCUMULATION RATES UP TO 2 INCHES OVER THE AREA
APPEARS LIKELY.

..CROSBIE.. 02/02/2003

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

43900996 42461063 41780987 41670736 42220678 42860666

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 2, 3:42 AM MST	Mesoscale Discussion	SPC	Converse, Natrona, Niobrara, Weston	5 hr

Nearby

Mesoscale Discussions in Wyoming, 2003 Every mesoscale discussion in 2003

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.