Alert archive / California / Snow Advisories in 2008

Snow Advisory 9, NWS Medford, OR

February 20, 2008Siskiyou County, California

NWS Medford, OR issued this snow advisory at Feb 20, 2008, 2:15 PM PST for Siskiyou County, California. It took effect at Feb 21, 2008, 10:00 AM PST. It was in force for .

The area

The counties it named.

The facts

Issued: Feb 20, 2008, 2:15 PM PST (22:15 UTC)
In effect from: Feb 21, 2008, 10:00 AM PST
Expired: Feb 21, 2008, 3:28 AM PST
In force
Issued by: NWS Medford, OR

County Siskiyou County, CA

The radar

The Medford radar (KMAX), 56 km from the middle of the area, began a volume at 22:12 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

Medford/Jackson, OR (KMFR), launched 12:00Z, 10.3 hours before the alert went out and 89 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: 6 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 564 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 0 m²/s²
0-3 km storm-relative helicity: 46 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this snow advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Medford, OR wrote its last area forecast discussion before this snow advisory went out at Feb 20, 8:44 AM PST, 5 hours 31 minutes earlier.

Area forecast discussion, Feb 20, 8:44 AM PST, 5 hours 31 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
844 AM PST WED FEB 20 2008

.SHORT TERM...AN UPPER LEVEL LOW IS MOVING SOUTH SOUTHEAST INTO
CENTRAL CALIFORNIA. SHOWERS HAVE TAPERED OFF OVER THE AREA THIS
MORNING ALTHOUGH A SPRINKLE OR TWO OVER HIGHER TERRAIN IS STILL
POSSIBLE. THE NEXT LOW PRESSURE SYSTEM IS CENTERED 850 MILES OFF
THE COAST OF BC WITH A WEAK FRONT EXTENDING SOUTHWARD. GFS AND NAM
ARE INDICATING THAT THE UPPER TROUGH WILL BECOME NEGATIVELY TILTED
AS A MODERATELY STRONG SURFACE LOW  DEVELOPS ALONG THE SOUTHERN
PORTION OF THE FRONT AND MOVES TOWARDS THE   NORTHERN CALIFORNIA AND
SOUTHERN OREGON COAST THURSDAY MORNING. THE GFS 12Z RUN SHOWS A MORE
SOUTHERN TRACK TO THE LOW VERSUS THE NAM 12Z RUN. THIS WOULD KEEP
THE STRONGER SURFACE WINDS OVER THE WATERS FURTHER SOUTH. THE ECMWF
SOLUTION SUPPORTS THE MORE SOUTHERN SOLUTION AS WELL. CURRENTL...AM
LEANING TOWARDS THE GFS AND ECMWF SOLUTIONS. THE NAM AND GFS ARE NOW
IN AGREEMENT ON THE INTENSITY OF THE LOW WITH A 998 TO 1000 MB LOW
MOVING INTO THE COAST THURSDAY. RAIN AND SHOW WILL SPREAD INTO THE
AREA DURING THE DAY THURSDAY. SNOW LEVELS ARE FORECAST AROUND 3000
TO 3500 FEET. QPF AMOUNTS ARE FORECAST TO BE LIGHT TO MODERATE WITH
THIS SYSTEM.

&&

.AVIATION...

&&

.PREV DISCUSSION... /ISSUED 314 AM PST WED FEB 20 2008/

LONG TERM...ANOTHER DEEP LOW IS EXPECTED TO WRAP NORTHWARD TOWARD
THE SOUTH COAST SATURDAY NIGHT INTO EARLY SUNDAY. NO REAL CONSENSUS
ON DEPTH AND TIMING OF THIS ONE EITHER...SO WILL NEED TO CONTINUE TO
MONITOR TRENDS AND PREPARE FOR POTENTIAL GUSTY SOUTH WINDS ON
THE COAST. RIDGING IS ADVERTISED OVER THE REGION MON-WED.

AVIATION...WIDESPREAD MVFR AND LOCAL IFR CIGS IN SW ORE WITH
PARTIAL MTN OBSCURATION WILL TRANSITION TO MOSTLY VFR AFT 18Z TDY.
E OF CASCADES CIGS WILL REMAIN MOSTLY VFR WITH WEAK PASSING UPPER
LOW TODAY THOUGH A FEW SHOWERS AND MVFR CIGS ARE PSBL THROUGH THE
MORNING HOURS.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 10 PM
     THIS EVENING TO 10 PM PST THURSDAY FOR PZZ356-PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM PST SATURDAY
     FOR PZZ350-PZZ356-PZZ370-PZZ376.
     SMALL CRAFT ADVISORY FOR WINDS FROM 10 PM THIS EVENING TO 4 PM
     PST THURSDAY FOR PZZ350-PZZ370.

CC

The office that day

Everything else NWS Medford, OR issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 20, 2:15 PM PST	Snow and Blowing Snow Advisory	MFR	Siskiyou	13 hr
Feb 20, 2:15 PM PST	Wind Advisory	MFR	Siskiyou	27 hr

Nearby

Snow Advisories in California, 2008 Every snow advisory in 2008

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.