Alert archive / California / Frost Advisories in 2006

Frost Advisory 3, NWS San Francisco Bay Area, CA

November 29, 20067 counties in California

NWS San Francisco Bay Area, CA issued this frost advisory at Nov 29, 2006, 3:52 AM PST for 7 counties in California. It took effect at Nov 29, 2006, 2:21 PM PST. It was in force for 19 hr.

The area

The counties it named.

The facts

Issued
Nov 29, 2006, 3:52 AM PST (11:52 UTC)
In effect from
Nov 29, 2006, 2:21 PM PST
Expired
Nov 30, 2006, 9:00 AM PST
In force
19 hr
Issued by
NWS San Francisco Bay Area, CA

Counties Alameda County, CA, Contra Costa County, CA, Marin County, CA, San Mateo County, CA, Santa Clara County, CA, Santa Cruz County, CA, Sonoma County, CA

The radar

The San Francisco radar (KMUX), 66 km from the middle of the area, began a volume at 11:56 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

Oakland, CA (KOAK), launched 00:00Z, 11.9 hours before the alert went out and 5 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-pSkew-T log-p diagram, Oakland, CA at 00:00Z on 2006-11-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 00:00Z on 2006-11-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
1324 m above ground
0-6 km bulk shear
72 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
43 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 frost advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this frost advisory went out at Nov 28, 9:00 PM PST, 6 hours 52 minutes earlier.

Area forecast discussion, Nov 28, 9:00 PM PST, 6 hours 52 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
900 PM PST TUE NOV 28 2006

.DISCUSSION...THE PASSING COLD FRONT AND RECENT RAIN ARE NOW A
DISTANT MEMORY AS HIGH PRESSURE WITH A COASTAL TROUGH BUILD IN.
TODAY TURNED OUT TO BE RATHER SUNNY COMPARED TO THE PREVIOUS FEW
DAYS. AS FAR AS TEMPERATURES GO...TODAYS HIGH TEMPERATURES WERE
CLOSE TO OR A FEW COOLER THAN YESTERDAY. MOST LOCATIONS RECORDED
MAX TEMPS IN 40S AND 50S...WITH THE EXCEPTION OF THE HIGH TERRAIN
WHERE 30S WERE NOTED.

THE WEATHER CONCERNS OVER THE NEXT 24-28 HOURS WAS NICELY DEFINED IN
THE SPECIAL WEATHER STATEMENT(SEE SFOSPSMTR).  CLEAR SKIES...CALM
WINDS IN THE VALLEYS AND A DRY AIRMASS WILL CREATE IDEAL
RADIATIONAL COOLING CONDITIONS. THE AIRMASS IS ALREADY COLD AND THIS
WILL FURTHER ENHANCE ANY COOLING TONIGHT. VALLEY LOCATIONS AWAY
FROM COAST AND URBAN CENTERS WILL SEE THE MOST COOLING WITH LOWS IN
THE 20S TO NEAR FREEZING. IT IS A GOOD POSSIBILITY THAT A FEW
RECORDS MAY BE BROKEN BY MORNING.

OTHERWISE...QUIET AND DRY WEATHER IS EXPECTED THROUGH THE FORECAST AS
HIGH PRESSURE BUILDS ALOFT AND AT THE SFC OVER MUCH OF THE SW
CONUS. AFTER THURSDAY...A GRADUALLY WARMING TREND WILL BE FELT
AS FLOW STARTS TO BECOME MORE OFFSHORE WITH BUILDING HIGH PRESSURE
OVER THE GREAT BASIN. NOT ONLY WILL TEMPERATURES WARM...BUT THIS
WILL CREATE A SET UP KNOWN FOR STRONG GUSTY WINDS IN THE HILLS
FRIDAY AND SATURDAY.

&&

.AVIATION...FOR 18Z/20Z TAF/TWEB CYCLE...COLD UPPER-LEVEL TROUGH
PULLING MOIST ONSHORE FLOW THROUGH DISTRICT THIS MORNING. SOUNDING
FROM KOAK AT 12Z INDICATED A VERY STRONG INVERSION AROUND 5500FT
MSL. SHOULD KEEP MOST PRECIPITATION ALOFT...BUT MAY INCLUDE ISOLD
-SHRAS IN TWEB ROUTES...ASSORTED TAFS THIS AFTERNOON (BTWN 22Z-02Z)
WITH BRIEF CIGS BKN035-045 WITH CONVECTIVE TEMPS IN MID/UPPER 40S
NORTH BAY...LOWER 50S SOUTH. MJV

&&

.MTR...WATCHES/WARNINGS/ADVISORIES.
      .TNT...SCA...PT ARENA TO POINT PIEDRAS BLANCAS.

PUBLIC FORECAST: MEHLE
AVIATION/MARINE: MJV

NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 29, 3:52 AM PSTFreeze WarningMTRAlameda, Contra Costa, Marin, Monterey, Napa, Santa Clara and 1 more29 hr

Nearby

Frost Advisories in California, 2006Every frost advisory in 2006

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.