Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/15/20

Area Forecast Discussion

National Weather Service San Diego CA

 901 PM PDT Sat Mar 14 2020

.SYNOPSIS...
Cool weather and scattered light showers or patchy drizzle will
continue into Monday along and west of the mountains under a deep
marine layer and persistent onshore flow. A low pressure system off
the northern California coast, will drop south through Wednesday
increasing the southwest winds, and the chance of rain and mountain
snow. It will be cooler as well, with lower snow levels. It will be
slightly warmer and drier into next weekend, but periods of showers
are still possible.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

Low clouds were widespread over the coastal basin this evening.
Recent MDCRS soundings show the moist layer is in excess of 6K FT
deep over San Diego County, and even deeper to the north. Onshore
surface pressure gradients this evening from KSAN to the deserts
were up to 10 MBS. This is supporting some SW wind gusts to 45 MPH
over the San Bernardino Mountains. Radar showed a few weak echoes
drifting NE off the coastal waters, enhancing a bit as they trek
inland over the Santa Ana Mts and on toward the San Bernardinos
where remote rain gages are measuring some small accumulations
through 8 PM PDT.

Based on short-term models and the moist layer depth, we will be
susceptible to drizzle and/or periods of light rain showers at times
into Monday morning. The gusty winds will continue as well,
especially over the mts/deserts. Most significant accumulations will
be on the coastal slopes. More significant periods of rain/snow are
still on track for the first half of the work-week. No forecast
changes.

From previous discussion... An extensive trough of low pressure
covers most of western North America and the eastern North Pacific,
with a closed upper low off the Oregon coast. This will maintain
cyclonic flow aloft over SoCal, with westerly winds in the lower
levels. With this, we can expect to cool, cloudy and unsettled
weather for the foreseeable future.

The deep cold low currently over the Pacific Northwest will
intensify as it moves south along the coast and is expected to
bring more precipiation Monday night through Wednesday. A strong
shortwave trough embedded in the mean cyclonic flow will move
eastward across south-central CA on Tuesday which will bring
an organized band of moderate rain and mountain snow. The closed
low slowly tracks across SoCal Wednesday with more showers and
snow levels lowering to around 3,500 feet. As the low moves in
from the north, we can also expect periods of strong and gusty
westerly winds in the mtns and adjacent desert areas. The details
remain uncertain as numerical model guidance continues to adjust
the timing and track of the low.

General troughing persists behind the departing low on Thursday and
Friday, and there may be scattered lingering showers at times
through Thursday, but the precipiation amounts will be lighter.
Friday may be dry but that remains uncertain.

The ensemble models show more low pressure systems upstream over
the eastern Pacific Thursday and Friday with the potential for
another closed low to form off the California coast next weekend.
Overall, the coming week will be cool with periods of rain and
mountain snow.

&&

.AVIATION...
150030Z...Coast/Valleys/Mountains...Widespread BKN-OVC clouds with
bases 2000-4000 feet MSL through tomorrow. Only partial clearing
expected Sunday afternoon. Areas of -SHRA will taper off tonight and
end Sunday morning. Visibility will remain 6+ miles through Sunday.

Deserts...Mostly clear with unrestricted vis through Sunday. Some
periods of high clouds at/above 15,000 ft through Sunday.

&&

.MARINE...
Breezy winds are possible over the coastal waters Monday and
Wednesday, mainly during the afternoons and evenings, with gusts up
to 20 kts.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...10/PG
AVIATION/MARINE...CO/Connolly