Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
940 am PDT sun Mar 29 2015
slightly cooler today as a weak trough moves across the area.
Greater cooling Tuesday through Thursday...with highs near normal
and night and morning low clouds and fog along the coast. Slight
coastal and valley warming Friday with weak offshore flow and a
shallow marine layer...then cooling across the region...a deeper
marine layer and breezy westerly winds in the mountains and
deserts next weekend.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
The 29/0000 UTC European model (ecmwf) and 29/0600 UTC GFS are in relatively good
agreement through the long-term.
At 9 am PDT...water vapor satellite imagery displayed an upper-
level low around 500 miles SW of San Diego...and a weak shortwave
trough moving across central California. Visible satellite showed middle/high
level clouds streaming over the region...and low clouds over the
coastal waters. Surface observations reported improved visibility
across most areas as fog lifts. High temperatures today will be
slightly cooler than yesterday as onshore flow increases and
heights lower with the approaching weak trough. Highs will be
around 5 to 15 degrees f above normal for this time of year.
Weak upper-level ridging will build over the area Monday and
Tuesday...maintaining above normal high temperatures and a shallow
marine layer to begin the week. Zonal flow will set up over the
region by middle week. This...and a few troughs moving by to our
north...will lower high temperatures to near normal by
Thursday...and create breezy westerly winds in the mountains and
deserts each afternoon and evening.
Weak offshore flow developing on Friday will warm coastal and
valley locations again into the 70s and 80s...and limit night and
morning low clouds and fog along the coast. Onshore flow will
quickly return next weekend as a weak trough approaches from the
west...creating a slightly deeper marine layer and lowering high
temperatures to slightly above normal for this time of year.
Breezy westerly winds...with local gusts near 55 miles per hour...will be
possible Saturday and Sunday over portions of the mountains and
291530z...coastal areas...patchy fog and low clouds will continue to
dissipate through 29/1630z. VFR conds with scattered-broken high clouds at or above
15000 feet mean sea level will prevail through this afternoon. Low clouds
returning after 30/0300z...with bases 500-1000 feet mean sea level and tops up to
1500 feet along with areas of fog where the clouds intersect terrain
in that layer.
Valleys/mountains/deserts...sct-bkn clouds at or above 15000 feet with
unrestricted visible through this evening.
830 am...patchy fog possible again tonight through Monday morning
though not likely to be dense. Otherwise no hazardous marine
weather is expected through Tuesday.
830 am...a south swell with a long period will create strong rip
and longshore currents through this afternoon...as well as
elevated surf along south-facing beaches. For details see the
beach hazards statement...laxcfwsgx. Slightly elevated surf will
continue through early next week though the rip current threat
will diminish as the swell period drops.
Skywarn activation will not be needed today.
California...beach hazards statement until 4 PM PDT this afternoon for Orange
County coastal areas-San Diego County coastal areas.