Wind Advisory 19, NWS San Diego, CA

831 
WWUS76 KSGX 311657
NPWSGX

URGENT - WEATHER MESSAGE
National Weather Service San Diego CA
957 AM PDT Wed Oct 31 2018

CAZ048-055-057-554-311800-
/O.EXP.KSGX.WI.Y.0019.000000T0000Z-181031T1700Z/
San Bernardino and Riverside County Valleys-The Inland Empire-
San Bernardino County Mountains-Santa Ana Mountains and Foothills-
Orange County Inland Areas-
Including the cities of Riverside, San Bernardino, Fontana, 
Rancho Cucamonga, Corona, and Running Springs
957 AM PDT Wed Oct 31 2018

...WIND ADVISORY WILL EXPIRE AT 10 AM PDT THIS MORNING...

The Santa Ana winds will continue decreasing through early 
afternoon.

$$

Moede

Area Forecast Discussion
National Weather Service San Diego CA
855 PM PDT Tue Oct 30 2018

.SYNOPSIS...
A Santa Ana pattern will bring warm, dry weather this week under
mostly clear skies. Gusty offshore winds tonight and Wednesday will
be strongest in the Inland Empire and the San Bernardino and Orange
County mountains and foothills.

&&

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

No changes were needed this evening. Winds have picked up this
evening with gusts of 30-40 mph recorded in some of the
canyon/foothill areas. Expect gusty Santa Ana winds to continue
overnight through Wednesday morning with gusts of 40-50 mph at times
in the canyon/foothill areas.

Previous forecaster discussion issued at 115 PM PDT:

Skies were clear this afternoon and the dry Santa Ana wind event is
just starting to get a foothold in the northern areas. The winds
have shifted northerly in the San Bernardino Mountains and Foothills
and a wind gust of 29 mph was reported at Heaps Peak at Noon. Winds
were also beginning to funnel through the Cajon Pass where Devore
had a gust of 39 mph at Noon. The highest peaks of the Santa Ana
Mountains also reported a wind shift to the northeast.

The north/northeast winds will strengthen tonight with offshore
pressure gradients from Nevada to San Diego peaking at around 11 mb
Wednesday morning as a 1027 mb high builds over the Great Basin.
This will support a period of moderately strong Santa Ana winds in
the San Bernardino and Orange County Mountains and foothills. Parts
of the Inland Empire below the Cajon Pass will also see strong winds
including Rialto, Rancho Cucamonga and Fontana. The winds will be
somewhat lighter farther downstream at Riverside and Corona.
Strongest winds gusts of 50 mph are most likely in the Santa Ana
mountains and foothills.

On Thursday and Friday the gradients weaken and the winds will not
be nearly as strong, but there will still be a diurnal uptick in
northeast winds late at night through midday.

Temperatures today were a little below average in most areas west of
the mountains, but that won't be the case again for a few days as
the airmass warms, the marine layer disappears and the downslope
flow adds a few degrees of warming. The mountains and deserts will
be a little below average Wednesday as cooler air advects from the
Great Basin plateau, followed by warmer days Thursday and Friday.

The weekend looks mild and dry with upper level northwest flow
between high pressure aloft over the eastern Pacific and a trough of
low pressure moving inland across the Great Basin. A shallow marine
layer and weak coastal eddy could bring low clouds and fog back to
locations near the coast Sunday and Monday.

&&

.AVIATION...
310335Z...A few patches of low clouds with bases near 2000 ft MSL
are possible in the coastal areas through about 10Z. After 10Z, a
few high clouds and unrestricted vis through Wed evening.

Areas of NE-E winds strengthening overnight with sfc gusts 25-40 kt.
Strongest winds will be on the coastal foothills and below the
passes and canyons. Winds will begin to subside by mid morning.
Pockets of LLWS and MOD-STG UDDFS possible over and S/SW of the
mountains. Winds will diminish by 01/00Z.

&&

.MARINE...
No hazardous marine weather is expected through Sunday.

&&

.FIRE WEATHER...
A burst of Santa Ana winds will elevate fire concerns tonight and
Wednesday morning in the San Bernardino Mountains, the Inland Empire
below the Cajon Pass, and the Santa Ana Mountains and Foothills.
Surface winds in these areas will be 15-30 mph with gusts of 40-50
mph. Humidities will fall to 5-10 percent. Winds elsewhere in the
Riverside and San Diego County mountains and foothills will not be
quite as strong.

The dry Santa Ana pattern will continue Thursday and Friday but with
much lighter winds and gradual humidity recovery.

&&

.SKYWARN...
Skywarn activation will not be needed this week.

&&

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

&&

PUBLIC/FIRE WEATHER...Moede/JMB
AVIATION/MARINE/BEACHES...SS