Alert archive / California / Special Weather Statements in 2021
Special Weather Statement, NWS Sacramento, CA
NWS Sacramento, CA issued this special weather statement at Jul 29, 2021, 4:07 PM PDT for El Dorado County, California. It was in force for 53 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jul 29, 2021, 4:07 PM PDT (23:07 UTC)
- Expired
- Jul 29, 2021, 5:00 PM PDT
- In force
- 53 min
- Issued by
- NWS Sacramento, CA
County El Dorado County, CA
The radar
The Reno radar (KRGX), 125 km from the middle of the area, began a volume at 23:08 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
Reno, NV (KREV), launched 12:00Z, 11.1 hours before the alert went out and 190 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
- 2873 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 16 m²/s²
- 0-3 km storm-relative helicity
- 39 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
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</html>What forecasters said that day
The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sacramento, CA wrote its last area forecast discussion before this special weather statement went out at Jul 29, 2:02 PM PDT, 2 hours 5 minutes earlier.
Area forecast discussion, Jul 29, 2:02 PM PDT, 2 hours 5 minutes before
Area Forecast Discussion National Weather Service Sacramento CA 202 PM PDT Thu Jul 29 2021 .SYNOPSIS... Late day mountain thunderstorm chances expected through the weekend. Above normal temperatures are expected through Friday with a slight cooling trend for the weekend and early next week. && .DISCUSSION... Ridge of high pressure remains centered over much of the Central US with the western edge situated over California. This will continue to bring southwest flow into interior Northern California, drawing in monsoon moisture into the area. Afternoon and evening shower and thunderstorm chances continue over the next several days. Thunderstorms already began forming over the Sierra late this morning, and best chances will remain along and east of the Sierra crest south of Plumas County and along the Coastal Range. Better chances of more widespread mountain showers and thunderstorms are possible tomorrow as the potential spreads north into the Shasta County mountains. Any thunderstorm may be accompanied by gusty and erratic winds, brief downpours, and lightning. Temperatures are forecast to remain above normal through tomorrow as high pressure remains over the area. Current temperatures around 1pm are overall similar to yesterday, and highs are forecast to top out around 100 to 108 degrees in the Valley and upper 70s to upper 90s in the mountains and foothills. Overnight temperatures are forecast to be fairly toasty once again tonight, only falling to the low to mid 70s in the Valley and foothills with some thermal belt locations in the foothills only falling to the low 80s. Wildfire smoke continues to impact temperatures around the Dixie Fire. Smoke is forecast to continue the diurnal flow that's generally been observed by draining into the northern Valley in the early morning hours before the southwest flow increases and pushes it back to the north/northeast. An upper level trough forming off of the eastern Pacific Coast will lower heights over Northern California this weekend, moderating temperatures. Temperatures are forecast to fall back to near normal by Saturday, which is 90s across the Valley and foothills and 70s to upper 80s in the mountains. -HEC && .EXTENDED DISCUSSION (Monday THROUGH Thursday)... Northern California will likely see southwesterly onshore flow over the region throughout the extended forecast period. Cluster analysis is in agreement high pressure over the Southwestern US and troughing off the Pacific Northwest Coast will keep Northern California near seasonal temperatures with little day to day change in the forecast. Thermal belts will also continue to see mild overnight lows. This pattern will also support a Delta Breeze. Some discrepancies emerge by the later part of the week in terms of the depth and location of the trough off the Pacific Northwest Coast. This could lead to some changes in the forecast from persistence by the weekend. && .AVIATION... VFR conditions at TAF sites with passing mid to high level clouds AOA 15K ft AGL. Local MVFR/IFR conditions in wildfire smoke over Plumas and Butte counties. Surface winds under 12 kts except local southwest gusts 25-30 kts vicinity west Delta. Isolated-scattered showers and thunderstorms over high elevations of the Sierra south of Tahoe with isolated activity north of Tahoe through 03z, weakening to isolated showers and dissipating after 07z. Chance of MVFR weather in heavier storms with isolated downdrafts G40 kts lee-side of Sierra. Temps AOA 105 deg F will result in density altitude 3000-3500 ft Thu and Fri afternoons. && .STO WATCHES/WARNINGS/ADVISORIES... None. &&
In the hours before
Special weather statement, Jul 29, 3:27 PM PDT, 40 minutes before
Special Weather Statement
National Weather Service Sacramento CA
327 PM PDT Thu Jul 29 2021
CAZ069-292330-
West Slope Northern Sierra Nevada-
327 PM PDT Thu Jul 29 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN TUOLUMNE...
SOUTHWESTERN ALPINE...NORTHEASTERN CALAVERAS AND EASTERN AMADOR
COUNTIES...
At 326 PM PDT, a strong thunderstorm was located 8 miles east of
Pinecrest, or 14 miles southwest of Sonora Pass, moving north at 10
mph.
Winds in excess of 30 mph and half inch hail are possible with this
storm.
Locations impacted include...
Bear Valley, Lake Alpine, Tamarack, Dardanelle, Lookout Peak and
Hermit Valley Basin.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 3814 11969 3809 11991 3852 12012 3860 11987
3857 11984
TIME...MOT...LOC 2226Z 164DEG 9KT 3819 11984
SLLSpecial weather statement, Jul 29, 4:07 PM PDT, 0 minutes before
Special Weather Statement
National Weather Service Sacramento CA
407 PM PDT Thu Jul 29 2021
CAZ069-300000-
West Slope Northern Sierra Nevada-
407 PM PDT Thu Jul 29 2021
...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT NORTHWESTERN ALPINE...
EASTERN EL DORADO AND NORTHEASTERN AMADOR COUNTIES...
At 406 PM PDT, strong thunderstorms were clustered over Kit Carson,
or near Kirkwood, moving northwest at 20 mph.
Winds in excess of 30 mph and half inch hail are possible with this
storm.
Locations impacted include...
Carson Pass, Kirkwood, Twin Bridges, Kirkwood Meadows, Upper Blue
Lake, Kirkwood Ski Area, Kyburz, Sierra At Tahoe, Kit Carson, White
Hall and Shriner Lake Campground.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 3849 12026 3893 12051 3902 12021 3898 12018
3885 12016 3882 12006 3873 11999 3869 11998
3868 11995 3860 11989
TIME...MOT...LOC 2306Z 157DEG 18KT 3866 12010
CSThe office that day
Everything else NWS Sacramento, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 29, 3:27 PM PDT | Special Weather Statement | STO | Alpine | 63 min |
Nearby
Special Weather Statements in California, 2021Every special weather statement 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.