Starting at 5pm PDT Friday night, 03/29/2024, the SF Bay Area Skywarn group will be activated. I will be monitoring the K6MPN repeater (444.500 MHz, +5.0 MHz offset, PL=100Hz CTCSS tone) and the N6NFI repeater (145.230 MHz, -0.600 MHz offset, PL=100Hz CTCSS tone) for severe weather and storm damage reports. Please keep in mind that we are SECONDARY users on the K6MPN repeater, which is a primary resource for the South County Amateur Radio Emergency Service (SCARES) group.

There are multiple alerts in effect for the SF Bay Area issued by the NWS WFO in Monterey, CA. See sfoskywarn.org/alerts for details. See https://poweroutage.us/area/state/california for current power outages in CA, listed by county.

Please email photos showing storm related damage or flooding to ckolovson – at – gmail.com.

Stay safe!
73, Curt Kolovson W6RQ
SF Bay Area Skywarn Coordinator

Key Points:
* Impactful weather system today into Saturday
* Moderate wind and water impacts anticipated
* Strong wind gusts may cause tree and power line damage
* Minor flooding potential from locally heavy rainfall
* Isolated thunderstorms with lightning and small hail
* Peak impacts this afternoon into Saturday evening

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5pm PDT Friday Mar 29 forecast:

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00Z Thurs Mar 28 (5pm PDT Wed Mar 27) Pacific forecast.

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00Z Thurs Mar 28 (5pm PDT Wed Mar 27) Pacific forecast:

12Z Fri Mar 29 (5am PDT Fri Mar 29) Pacific Forecast. Looks like the makings of an impactful storm.

The next storm is currently expected to arrive Wed morning. A more intense storm system may be coming by late in the week or the weekend.

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NWS OPC forecast for 00Z Sun Mar 24 (5pm PDT Sat Mar 23). Front has passed. A series of minor surface troughs will be passing through, which could bring some isolated locally heavy winds, t-storms, and small hail.

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12Z Mar 23 (5am PDT Mar 23) surface analysis shows surface trough that has already passed through. This was the minor trough of concern. Others may follow, such as the approaching one shown in the 00Z Mar 24 forecast above.

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18Z Mar 23 (11am PDT Mar 23) sfc analysis:

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NWS OPC Forecast valid 00Z Sat 3/23 (5pm PDT Fri 3/22). Cold front is passing through Bay Area, immediately followed by low pressure system and associated trough that will bring convective lifting and the possibility of thunder storms. This is not expected to be a big rainmaker overall, but there is a possibility of locally heavy rain, moderate to high winds, small hail, and some thunder and lightning.

Possibility of t-storms, especially on Saturday.

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Forecast for 00Z Saturday (5pm PDT Friday). The cold front is expected to pass through the Bay Area late Friday, with the trough behind it. Note the large storm in the mid-Pacific that may impact us by the middle of next week.

New storm system arrives on Friday.

Surface map forecast for 12Z (5am PDT) Friday Mar 22. Source: NWS Ocean Prediction Center (OPC):

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From latest AFD:

.SYNOPSIS...
Issued at 159 AM PST Sat Mar 2 2024

A cold front is moving through the Bay Area early this morning.
Showers and strong westerly wind will continue Saturday before
tapering off Sunday. Cold temperatures will persist through
Monday.

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.SHORT TERM...
(Today and tonight)
Issued at 159 AM PST Sat Mar 2 2024

The surface cold front is currently moving through the Bay Area.
Doppler radar velocity data and higher elevation anemometers are
indicating winds are gusting as high as 55 mph as the frontal
boundary passes. Rain showers continue, although the coverage has
decreased overnight. The post-frontal environment will likely
continue to support this lull in precipitation Saturday morning,
and there will even be some sunshine. By Saturday afternoon, the
combination of surface heating and cold middle levels will
decrease the stability and will likely lead to a final round of
strong showers and possible low-topped thunderstorms. Winds will
subtly shift from SW to westerly behind the front, and remain
strong through the day.

&&

.LONG TERM...
(Sunday through Friday)
Issued at 159 AM PST Sat Mar 2 2024

High pressure will quickly build behind the front and the gradient
will relax by Sunday. There may still be a few showers, but they
will be lighter than Thu-Sat. Winds will also be lighter on
Sunday, but there will still be a moderate westerly breeze in the
afternoon. The biggest impact will shift from wind and rain to
cold morning temperatures. The low temps on Sunday and Monday
morning are expected to range from mid-30s to low-40s.

A weak system will move through in the middle of the week. This
will keep the cooler temperatures, cloud cover, and light rain
chances in the forecast through Tuesday or Wednesday. High
pressure finally rebuilds late week. Thursday and Friday look to
be clear and calm, with more normal temperatures. For example, the
Thursday high temperature at Santa Rosa is expected to climb back
to the mid-60s for the first time in a week.