Bryn Mawr, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

653
FXUS66 KSGX 041835
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1000 AM PST Wed Dec 4 2024

.SYNOPSIS...
High pressure aloft and developing weak offshore flow will bring
well above average high temperatures in inland areas through this
weekend. Areas of night and morning low clouds and fog, locally
dense, will occur in coastal areas through Friday morning. A low
pressure system from the northwest will bring cooling early next
week with gusty west to northwest winds in the mountains and deserts.

&&

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

Low clouds and fog had mostly cleared western San Diego County by 10
AM but were still covering many parts of Orange County. Skies should
clear back to the coast in Orange County by noon, and temperatures
will generally be deg F above normal this afternoon inland, though
near or a little below normal near the coast. With the marine layer
getting more shallow tonight then, there could be a little bit of
dense fog over higher coastal terrain, and perhaps near the
immediate coast Thursday night before the marine layer will likely
become minimal.

A closed low aloft will likely remain over Arizona through Friday
and then only very slowly drift to the east as a high pressure ridge
extends from the East Pacific through California and the Great
Basin. This will be an offshore flow pattern, though high-resolution
models indicate any Santa Ana winds to be weak to locally moderate.
Through Thursday night, most of the winds appear to be along the
mountain ridges, but some of the gusty winds could come down into
the valleys, especially the Inland Empire, Friday through Saturday.
Current gust potential is to around 40 MPH in the windiest locations
south of Cajon Pass. Humidity will be low with some 10-15 percent
values mainly Saturday for elevated to locally near critical fire
weather conditions. It should be quite mild across the region with
highs Friday-Saturday around 80 or even a little above at most lower
elevation locations away from the immediate coast.

A cooling trend will occur early next week with a long-wave trough
moving southeast from the Pacific coast off of British Columbia
through much of the western US. This should be a dry trough for
SoCal, but it could be accompanied by a moderate Santa Ana wind
event due to a surface high pressure center developing in the Great
Basin and cold air advection from the northeast.

&&

.AVIATION...
041700Z....Coasts/Valleys...Low clouds based around 800-1200ft MSL
are starting to retreat in southern San Diego County, but should
hold on for another hour or so in Orange County before eventually
clearing by 19z. VIS reductions to 3-5SM remain possible in the
western valleys and higher terrain until the clouds clear. VFR
prevails through the afternoon until low clouds move back ashore
after 01z. These clouds should only reach about 5-10 miles of inland
extent tonight, with lower bases around 500-1000ft MSL. Reduced VIS
1-5SM possible, especially on mesas and higher coastal terrain.

Otherwise...VFR and mostly clear skies prevails through Thursday
morning.

&&

.MARINE...
No hazardous marine weather conditions are expected through Sunday.

&&

.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...Maxwell
AVIATION/MARINE...Munyan