091 
FXUS66 KSGX 061730
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
930 AM PST Thu Feb 6 2020

.SYNOPSIS... 
Dry weather with about normal temperatures can be expected through 
Saturday. Patchy low clouds will return to the coast tonight, 
becoming more widespread through the weekend. On Sunday, an area of 
low pressure will move over the West Coast bringing an increase in 
clouds, gusty west winds, and a chance of precipitation through 
Monday. Low pressure will linger over the West Coast through the end 
of next week, bringing a prolonged period of cooler weather and more 
chances of precipitation.

&&

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

As of 9 AM, it was 5 to 10F warmer than at 9 AM yesterday. The 
pressure gradient from San Diego to Tonopah, NV had transitioned to 
slightly onshore. A coastal eddy is expected to form today, which 
will help generate patchy marine layer clouds and fog along the 
coast this evening and overnight. Low clouds are expected to become 
more widespread along the coast through the weekend. An area of high 
pressure offshore will build through Saturday, bringing seasonal 
weather with some high clouds at times. 

A pattern shift will occur Sunday, as a low pressure system makes 
its way over the West Coast. This system will bring an increase in 
cloud cover, cooler weather, gusty west winds, and an increased 
chance of precipitation. The best chance of rain is Sunday night 
into Monday, but light rain could begin as early as Sunday morning 
and linger into Tuesday. Precipitation totals will be largely 
dependent on the track of the storm system. There are still track 
differences between both the GFS/ECMWF deterministic models, and the 
global ensembles. Given the uncertainties in the storm track, 
confidence is low regarding to how much precipitation will fall. 

The preliminary estimates for rainfall totals are one-tenth of an 
inch along the coast and one-tenth to one-quarter of an inch in the 
valleys and on the coastal mountain slopes. Only a few hundredths 
are expected in the deserts. At this time, it looks like up to 2 
inches of snow are possible in the San Bernardino mountains, with an 
inch or less expected in the Riverside County mountains.

A troughing pattern will prevail over the West Coast, bringing 
cooler and breezy weather next week. Additional precipitation is 
possible, but with much lower confidence regarding timing of any 
periods of additional precipitation. 

&&

.AVIATION... 
061730Z...Scattered high clouds expected today and tonight. 
Patchy low clouds could return to the coast after 06Z Friday, but 
confidence is low in impacts to coastal TAF sites. 

&&

.MARINE...
No hazardous marine weather is expected through Saturday. A storm 
system will bring stronger and shifting winds late Sunday and 
Monday, but with only isolated gusts 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...CO/10
AVIATION/MARINE...PG/MM