Alert archive / California / Mesoscale Discussions in 2004

Mesoscale Discussion 65

February 2, 200410 counties in California

The Storm Prediction Center issued this mesoscale discussion at Feb 2, 2004, 1:40 AM PST for 10 counties in California. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Feb 2, 2004, 1:40 AM PST (09:40 UTC)
Expired: Feb 2, 2004, 6:15 AM PST
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Amador County, CA, El Dorado County, CA, Mariposa County, CA, Nevada County, CA, Placer County, CA, Plumas County, CA, Shasta County, CA, Sierra County, CA, Trinity County, CA, Tuolumne County, CA

The nearest sounding before it

Oakland, CA (KOAK), launched 00:00Z, 9.7 hours before the alert went out and 195 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: 565 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 149 m²/s²
0-3 km storm-relative helicity: 294 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.

470 
ACUS11 KWNS 020941
SWOMCD
SPC MCD 020940 
CAZ000-021415-

MESOSCALE DISCUSSION 0065
NWS STORM PREDICTION CENTER NORMAN OK
0340 AM CST MON FEB 02 2004

AREAS AFFECTED...COASTAL AND SIERRA MTNS OF CA ABOVE 3000

CONCERNING...HEAVY SNOW 

VALID 020940Z - 021415Z

HEAVY SNOW AND ISOLATED THUNDERSNOW TO OVERSPREAD COASTAL MTNS AND
SIERRAS ABOVE 3 KFT BEGINNING AT 12Z. SEVERAL HOURS OF 2/HR SNOW
RATES LIKELY.

AT 09Z...GOES-10 WV IMAGERY SHOWED LARGE UPPER TROUGH MOVING EWD
ACROSS ERN PACIFIC WITH POTENT LEAD SHORTWAVE TROUGH AXIS 250NM WEST
OF THE NRN CA COAST. MOSAIC RADAR INDICATED STRONG FRONTAL
PRECIPITATION BAND 70W OF CAPE MENDOCINO WITH ISOLATED CG STRIKES
WITH EMBEDDED CONVECTION PER LIGHTNING DETECTION NETWORK.
LINE MOVEMENT IS 260/30KT. EXTRAPOLATION TAKES HEAVY PRECIPITATION
INTO COASTAL RANGES BETWEEN 12-13Z...AND INTO THE NRN SIERRA MTNS
BETWEEN 14-15Z.

SHORT-RANGE NUMERICAL GUIDANCE GENERALLY CONSISTENT IN UVV AND QPF
SIGNAL ACROSS DISCUSSION AREA. THE 3-HRLY LIQUID EQUIVALENT PRECIP
IN 00Z ETA RUN TOTAL NEAR 0.5 BETWEEN 12-15Z IN THE COASTAL RANGES
WITH SIMILAR TOTALS IN THE NRN SIERRA MTNS 15-18Z. STRONGEST UVV
SHIFTS INTO THE SRN SIERRA MTNS THEREAFTER. STRONG OROGRAPHIC LIFT
WITH 40KT SWLY FLOW AT 700MB AND LAPSE RATES OF 7C/KM IN 700-500MB
LAYER WILL AUGMENT IMPRESSIVE SYNOPTIC LIFT AND LIKELY PRODUCE
SEVERAL HOURS OF 2/HR SNOW RATES AS FRONTAL BAND TRANSLATES ACROSS
THE REGION. ETA MODEL SOUNDINGS SUGGEST SNOW LEVELS GENERALLY
BETWEEN 3000-4000 FT THROUGH 18Z.

..BANACOS.. 02/02/2004

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

ATTN...WFO...REV...HNX...MFR...STO...EKA...

38982014 38331976 37701935 37341949 37321977 37622008
37862032 38502070 39082106 39662136 40752218 40492270
39662283 40542325 41222273 41492199 40752118

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 2, 12:31 PM PST	Mesoscale Discussion	SPC	Alpine, El Dorado, Mariposa, Nevada, Placer, Tuolumne	6 hr

Nearby

Mesoscale Discussions in California, 2004 Every mesoscale discussion in 2004

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.