Discussione scientifica sulle previsioni

NWS Discussion
			
				

Area forecast discussion 
National Weather Service San Diego California 
940 am PDT Sat may 25 2013 


Synopsis... 
upper level trough of low pressure will remain over the West Coast 
this week...with temperatures remaining near to below average and 
onshore flow continuing. Therefore...expect a deep marine layer to 
persist...with areas of night and morning low clouds and fog 
possible each day...with gusty west winds in the mountains and 
deserts each afternoon and evening. 


&& 


Discussion...for extreme southwestern California including Orange... 
San Diego...western Riverside and southwestern San Bernardino 
counties... 


Water vapor imagery continues to show a broad trough of low pressure 
over the West Coast this morning...with several disturbances 
rotating around and through this trough. As a result...relatively 
strong onshore flow continues across Southern California this 
morning...with the San Diego to Daggett and the San Diego to thermal 
gradient both at 6.3 mbs...or roughly 2 mbs stronger than this time 
yesterday morning. Although the marine layer is roughly 200 feet 
lower in height this morning as compared to yesterday...the 12z knkx 
sounding still shows it around 3200 feet deep. For this 
reason...saw another good push inland across the valleys this 
morning...with visible imagery showing low clouds even extending up 
into the Cajon Pass. Currently...visible imagery shows that most of 
the low clouds have cleared San Diego County...but hanging on strong 
across Orange County and the northern inland Empire. It will take a 
while for these clouds to burn off...so have updated the forecast to 
reflect current trends and thinking. 


Only minor fluctuations in the forecast will be possible over the 
next several days...as this trough remains in place along the West 
Coast. Models are hinting at some drizzle or light showers possible 
late Monday night and into Tuesday...as the marine layer deepens to 
around 5000 feet. Otherwise...expect near to below normal 
conditions to continue to prevail across the Southland...as strong 
onshore flow continues and a deep marine layer persists. Locally 
gusty west winds will also be possible in the mountains and deserts 
each afternoon through the late evening...potentially flirting with 
advisory type strengths at times. 


&& 


Aviation... 
251500z...coast/valleys...stratus clouds with bases around 2500 feet 
mean sea level and tops 3500 feet mean sea level will erode to the coast this morning 
between 25/1600z-1800z with skies becoming few/sct. Stratus will 
again spread 15-20 sm inland between 26/0100z-0300z this evening. 
Bases similar to this morning...around 2500 feet mean sea level and tops 2500 feet 
mean sea level. Visible will remain above 5 sm...locally lower where the clouds 
intersect terrain. 


Mtns/deserts...mostly clear with unrestricted visible through Sunday 
afternoon. Gusty surface west winds to 35 knots will develop Sunday 
afternoon over the Desert Mountain slopes and through/east of San 
Gorgonio Pass. 


&& 


Marine... 
astronomical high tides to 7.2 feet and below normal low 
tides...with swings of 8.9 feet...will combine with slightly above 
normal surf to bring a small chance of minor coastal flooding 
through Memorial Day. The highest high tides will take place in the 
late evenings and the lowest low tides will be in the early 
mornings. Strong rip currents will continue through Memorial 
Day...partly due to the swings in The Tides. 


&& 


Sgx watches/warnings/advisories...none. 


&& 


$$ 


Public...Palmer 
aviation/marine...jt