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Auggie

(31,775 posts)
Mon Mar 6, 2023, 12:07 PM Mar 2023

Weather models trending towards possible NorCal atmospheric river this weekend

This weekend = March 10-12. Excerpts below detail some pretty cool weather science.

San Francisco Chronicle / March 6, 2023

Wet low-pressure systems continue to chip away at the foundation of a high-pressure system just off the coast of California. Like a dam that’s full of leaks, the foundation of the high-pressure system will continue to fall apart as more rain and thunderstorms break through. If this keeps up, the high-pressure system could collapse by Friday, allowing a torrent of atmospheric moisture to flow into the Bay Area on the weekend.

The European, American and Canadian weather models are all suggesting that low-pressure systems will chip away at the Pacific High between Monday and Friday. This means that more rounds of rain showers and thunderstorms will make it onto the coast over the next few days, with isolated pockets of hail, damaging winds and lightning strikes all on tap for the Bay Area . By Thursday the weather models begin to suggest different outcomes for what will happen to the Pacific High. A couple scenarios keep it intact, meaning that only light showers and drizzles will be possible this weekend. But other scenarios suggest a complete collapse of the Pacific High, allowing an atmospheric river to rush toward Northern California.

Any low-pressure system that’s around to absorb all that moisture this weekend will evolve into a storm that could bring excessive rainfall to the Bay Area, Sacramento Valley, and Central Coast. The Sierra Nevada and peaks in Southern California would also get whacked again, on top of the historic snowpack that’s already sitting over the mountains.

For now, the weather models are still sifting through both scenarios. But with this winter already wetter than predicted by September’s long-range outlook, there is precedent for the advent of the wetter scenario, lining up with trends from the past few months.

LINK (paywall): https://www.sfchronicle.com/weather-forecast/article/atmospheric-river-bay-area-17821559.php

13 replies = new reply since forum marked as read
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Weather models trending towards possible NorCal atmospheric river this weekend (Original Post) Auggie Mar 2023 OP
Yup... 2naSalit Mar 2023 #1
Wow! Thanks for sharing this! Auggie Mar 2023 #3
we r in a sunny break. i have run out of one of my critical meds . most are up the hill AllaN01Bear Mar 2023 #2
pg and e metero long range forecast AllaN01Bear Mar 2023 #4
"Details are still evolving" Auggie Mar 2023 #5
si. AllaN01Bear Mar 2023 #6
Stay safe AllaBear. 🥰 Polly Hennessey Mar 2023 #9
fancy talk for they dont know. AllaN01Bear Mar 2023 #7
One could call it an "educated guess to cover one's ass." Auggie Mar 2023 #8
snow level rising to 8000ft + heavy rain equals massive snow melt and flooding nt msongs Mar 2023 #10
Not good Auggie Mar 2023 #11
Not good? BidenRocks Mar 2023 #12
Yeah, not good. A slow snow melt is preferable to a fast one. Auggie Mar 2023 #13

AllaN01Bear

(23,001 posts)
2. we r in a sunny break. i have run out of one of my critical meds . most are up the hill
Mon Mar 6, 2023, 12:38 PM
Mar 2023

from me and snowed in. will have to take a cab to mrrow . but more snow fore casted for tonite .

AllaN01Bear

(23,001 posts)
4. pg and e metero long range forecast
Mon Mar 6, 2023, 12:42 PM
Mar 2023
https://pgealerts.alerts.pge.com/updates/7day/
i aint going to para phrase them so look at it.
mark thyman , research metoroligist out of kcra 3 tv sacramento on a long range fore cast of his on sunday said wed see a break en the weather for four days. we shall see no.?

Auggie

(31,775 posts)
5. "Details are still evolving"
Mon Mar 6, 2023, 12:46 PM
Mar 2023

That's from your link, essentially what the S.F. Chronicle is reporting.

We are being alerted, akin to hurricane projections.

Auggie

(31,775 posts)
8. One could call it an "educated guess to cover one's ass."
Mon Mar 6, 2023, 12:53 PM
Mar 2023

And I'm okay with that. These folks are experts.

A little preparation, even if for naught, never hurt anybody.

BidenRocks

(930 posts)
12. Not good?
Mon Mar 6, 2023, 06:46 PM
Mar 2023

Have you seen pictures of Lakes Mead, Powell, Oroville?
How about the Colorado River?
We were slowly dying.
I do feel for those impacted.
All I can do is donate.

Auggie

(31,775 posts)
13. Yeah, not good. A slow snow melt is preferable to a fast one.
Mon Mar 6, 2023, 07:47 PM
Mar 2023

Lot's of warm rain + heavy snow pack = flooding, mudslides, levee failures, etc.



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