Alert archive / California / Winter Weather Advisories in 2021
Winter Weather Advisory 22, NWS Eureka, CA
NWS Eureka, CA issued this winter weather advisory at Dec 15, 2021, 10:09 PM PST for Del Norte County, Humboldt County, Trinity County, California. It was in force for 8 hr.
The area
The counties it named.
The facts
- Issued
- Dec 15, 2021, 10:09 PM PST (06:09 UTC)
- Expired
- Dec 16, 2021, 6:03 AM PST
- In force
- 8 hr
- Issued by
- NWS Eureka, CA
Counties Del Norte County, CA, Humboldt County, CA, Trinity County, CA
The radar
The Eureka (Bunker Hill) radar (KBHX), 80 km from the middle of the area, began a volume at 06:08 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 00:00Z, 6.2 hours before the alert went out and 165 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 637 m above ground
- 0-6 km bulk shear
- 69 kt
- 0-1 km storm-relative helicity
- 323 m²/s²
- 0-3 km storm-relative helicity
- 419 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
073 WWUS46 KEKA 160609 WSWEKA URGENT - WINTER WEATHER MESSAGE National Weather Service Eureka CA 1009 PM PST Wed Dec 15 2021 CAZ102-105>108-161415- /O.EXP.KEKA.WS.W.0008.000000T0000Z-211216T0600Z/ /O.NEW.KEKA.WW.Y.0022.211216T0609Z-211216T1500Z/ Del Norte Interior-Northern Humboldt Interior- Southern Humboldt Interior-Northern Trinity-Southern Trinity- 1009 PM PST Wed Dec 15 2021 ...WINTER WEATHER ADVISORY IN EFFECT UNTIL 7 AM PST THURSDAY... * WHAT...Scattered snow showers may bring additional snow accumulations of up to 4 inches overnight, particularly at higher elevations. * WHERE...Del Norte Interior, Northern Humboldt Interior, Southern Humboldt Interior, Northern Trinity and Southern Trinity Counties. * WHEN...Until 7 AM PST Thursday. * IMPACTS...Plan on slippery road conditions. The hazardous conditions could impact the morning commute. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state of California can be obtained by calling 1-800-GAS-ROAD. && $$ CAZ110-111-114-160715- /O.EXP.KEKA.WS.W.0008.000000T0000Z-211216T0600Z/ Northwestern Mendocino Interior-Northeastern Mendocino Interior- Northern Lake- 1009 PM PST Wed Dec 15 2021 ...WINTER STORM WARNING HAS EXPIRED... Scattered rain and snow showers are expected through the night, but new accumulations are expected to remain below 2 inches. $$
1 follow-up statement
116 WWUS46 KEKA 161403 WSWEKA URGENT - WINTER WEATHER MESSAGE National Weather Service Eureka CA 603 AM PST Thu Dec 16 2021 CAZ102-105>108-161515- /O.CAN.KEKA.WW.Y.0022.000000T0000Z-211216T1500Z/ Del Norte Interior-Northern Humboldt Interior- Southern Humboldt Interior-Northern Trinity-Southern Trinity- 603 AM PST Thu Dec 16 2021 ...WINTER WEATHER ADVISORY IS CANCELLED... Scattered showers will linger this morning with snow possible above 3000ft. Less then 2 inches of new snow accumulation is expected. $$
What forecasters said that day
The local office's own words before this winter weather advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Eureka, CA wrote its last area forecast discussion before this winter weather advisory went out at Dec 15, 8:10 PM PST, 1 hour 59 minutes earlier.
Area forecast discussion, Dec 15, 8:10 PM PST, 1 hour 59 minutes before
AREA FORECAST DISCUSSION National Weather Service Eureka CA 255 PM
PST Wed Dec 15 2021
.SYNOPSIS...A winter storm is moving across the northwest CA
interior this afternoon. Moderate to heavy snow has been falling
since late this morning affecting elevations above 2000 feet. Rain
across lower elevations will change to showers over night and all
weather conditions will improve Thursday as the storm exits the
region.
&&
.DISCUSSION...Interesting weather day across the region as a
moderate winter storm moved overhead. This storm was highlighted by
plenty of snow to elevations generally above 2000 feet. At this time
reports of 4 to 10 inches across interior communities and highways
are common. For elevations above 3500 feet a foot or more is likely.
For coastal areas and lower elevations rain was common but not
heavy. About a third of an inch fell around Humboldt Bay with higher
amounts northward toward Crescent City. Wind was also vigorous at
times with gusts along the coastal headlands reaching 35 to 45 mph
and some higher elevations along the coastal interior exceeding 50
mph. On the back edge of the front a line of convective
thunderstorms formed over the coastal waters warranting the issuance
of a Marine Weather Statement. At this time the front is moving
across Trinity County supplying additional snow to that area. Given
the front has nearly moved through will likely end the Winter
Weather Warning currently in effect until 7pm. All Wind Advisories
and Warnings have also ended. Precipitation will ease overnight with
some lingering showers expected Thursday alongside gradually warming
conditions. Essentially all cluster ensemble members show ridging on
Friday and Saturday, brining a brief respite to winter rain.
Conditions will remain cool and moist with clear to partly cloudy
skies for the interior. Stratus and low marine fog can be expected
along the coast. If skies stay clear, valley fog and frost along the
coast could form Friday morning. About 60% of cluster ensemble
members show a modest shortwave on Sunday, bringing another round of
rain, mostly focused on the coast north of Humboldt Bay. Long range
NBM forecasts show snow levels above 4000ft, keeping winter weather
concerns low. About 80% of ensemble members seem to be converging on
another strong storm system hitting sometime early next week. Snow
levels will likely be low enough to bring another round of snow to
the Trinity Alps and high elevation passes./JHRW/JT
&&
.AVIATION...Rainfall and gusty southerly winds have prevailed today,
with a transition to more isolated showers through the afternoon.
Some IFR CIGS and VIS have been observed. Low-level wind shear has
ended with the passing of the front and associated strong southerly
winds aloft. More light rainfall will occur overnight before showers
taper off tomorrow morning. Winds will trend much lighter, but will
remain a little gusty overnight through tomorrow morning as the
direction generally veers more westerly. MVFR CIGS will mostly
continue overnight, with times of IFR VIS possible.
&&
.MARINE...Strong southerly winds accompanied by gale force gusts
will remain near the shore off our Southern Coastal zones until
early this afternoon, but overall, the southerlies will continually
decrease throughout the afternoon. After the frontal passage, winds
will continue to back off during the evening as they turn to
westerlies. Through much of Thursday, weaker northerly winds will
develop over the coastal waters. Stronger southerlies are projected
to return Saturday morning and slowly increase throughout the day as
the next front approaches. The current large northwest swell will
continue to wane. But then, another strong NW swell will begin to
move through our coastal waters by late tonight. As that swell
declines, a weaker west to northwest swell is forecast to move
through the coastal waters by Saturday night. /JLW
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA... Wind Advisory until 3 PM PST this afternoon for CAZ102>115.
Winter Storm Warning until PM PST this evening for CAZ102- 11
105>108-110-111-114.
High Wind Warning until 3 PM PST this afternoon for CAZ101.
NORTHWEST CALIFORNIA COASTAL WATERS...
Wind Advisory until 3 PM PST this afternoon for PZZ410.
Gale Warning until 3 PM PST this afternoon for PZZ450-455.
Hazardous Seas Warning until 9 PM PST this evening for
PZZ450-455.
Hazardous Seas Warning until 9 PM PST this evening for
PZZ470-475.
&&
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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.pngHazardous weather outlook, Dec 15, 2:40 PM PST, 7 hours 29 minutes before
Hazardous Weather Outlook National Weather Service Eureka CA 240 PM PST Wed Dec 15 2021 CAZ103-104-109-112-113-115-162245- Northern Humboldt Coast-Southwestern Humboldt-Mendocino Coast- Southwestern Mendocino Interior-Southeastern Mendocino Interior- Southern Lake- 240 PM PST Wed Dec 15 2021 This hazardous weather outlook is for Northwest California. .DAY ONE...This afternoon and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. CAZ101-162245- Coastal Del Norte- 240 PM PST Wed Dec 15 2021 This hazardous weather outlook is for Northwest California. .DAY ONE...This afternoon and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. CAZ102-105>108-110-111-114-162245- Del Norte Interior-Northern Humboldt Interior- Southern Humboldt Interior-Northern Trinity-Southern Trinity- Northwestern Mendocino Interior-Northeastern Mendocino Interior- Northern Lake- 240 PM PST Wed Dec 15 2021 ...WINTER STORM WARNING IN EFFECT UNTIL 7 PM PST THIS EVENING ABOVE 2500 FEET... This hazardous weather outlook is for Northwest California. .DAY ONE...This afternoon and tonight. A Winter Storm Warning is currently in effect above 2,500 feet through 7 p.m. this evening. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
In the hours before
Local storm report, Dec 15, 5:18 PM PST, 4 hours 51 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EUREKA CA
518 PM PST WED DEC 15 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0516 PM SNOW 3 WSW LEWISTON 40.69N 122.86W
12/15/2021 M7.0 INCH TRINITY CA TRAINED SPOTTER
WET SNOW FALLING ALL DAY, MEASURED VALUE IS
TOTAL AS OF 5 PM LST. STATION ELEVATION:
1808 FT.
&&
TJThe office that day
Everything else NWS Eureka, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 15, 8:34 PM PST | Small Craft Advisory | EKA | 34 hr | |
| Dec 16, 4:21 AM PST | Frost Advisory | EKA | Del Norte, Humboldt, Mendocino | 29 hr |
| Dec 16, 5:15 AM PST | Small Craft Advisory | EKA | 25 hr | |
| Dec 16, 5:15 AM PST | Hazardous Seas Warning | EKA | 4 hr |
Nearby
Winter Weather Advisories in California, 2021Every winter weather advisory in 2021
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.