Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
926 am PDT Wednesday Oct 7 2015
dry and hot for the end of the week as high pressure builds aloft
and weak offshore winds develop at the surface. Slow cooling next
week and a possible return of wet weather middle to late next week.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
At 9 am PDT...water vapor satellite imagery displayed an upper-
level low centered over south-central Arizona...and a broad upper-level
ridge centered around 650 miles SW of San Diego...stretching into
central California. Visible satellite showed mostly clear skies across the
County Warning Area. The 07/0000 UTC European model (ecmwf) and 07/0600 GFS are in relatively good
agreement with the overall pattern through the long-term...but
differ some in the details.
A warming trend will continue through the end of the week as the
upper-level ridge builds over central California. 500 heights will peak
around 590-592 dm and h850 temperatures will increase to around 24 degree c
over SW California on Friday. The ridge and surface offshore pressure
gradients from San Diego to Salt Lake City of around 9 mb will
help create very warm weather Friday and Saturday...with high
temperatures forecast to rise 5 to 15 degree f above normal. The
coast will also become quite hot as the marine layer becomes very
shallow. Highs will be close to heat advisory criteria Friday and
Saturday. Northeasterly wind gusts around 30 miles per hour will develop
along coastal mountain slopes in San Bernardino and Riverside
counties Friday morning. A surface high then building near The
Four Corners will create easterly wind gusts near 25 miles per hour along the
San Diego County coastal mountain slopes and foothills Saturday
morning. Onshore surface pressure gradients will slowly increase
Sunday and Monday as the ridge aloft weakens.
The nearby upper-level low will swing back around towards SW California
from the SW middle to late next week...increasing the possibility of
showers and thunderstorms and continuing a cooling trend across
most areas. Showers may begin over the mountains Tuesday
afternoon...then become more widespread Wednesday and Thursday.
Models differ somewhat in the locations and timing of precipitation.
Confidence of precipitation occurring over SW California will continue to
increase as each model run shows a similar solution.
071505z...few-sct clouds in the 5000-12000 feet mean sea level layer over the
mountains through 08/0000 UTC. Also...slight chance for a few
patches of stratus/fog within 5 to 15 sm of the coast during the
08/0300-1500 UTC time-period with bases around 300-800 feet mean sea level...tops
around 800-1000 feet mean sea level...and local visible at or below 1/2 sm.
However...confidence in stratus/fog occurrence is low for
ksan...kcrq and ksna. Otherwise...mostly unrestricted visible with
increasing clouds at or above 20000 feet mean sea level through Thursday morning.
805 am...no hazardous marine weather is expected through Sunday.
805 am...a 3 foot/18 second southwest swell will likely produce
strong rip currents and elevated surf of 3 to 5 feet at southwest
facing beaches over the weekend.
Skywarn activation will not be needed today.