Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 232148
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
248 PM PDT TUE AUG 23 2016
.SYNOPSIS...Scattered showers and thunderstorms can be expected
over mainly the higher elevations of the Sierra through this
evening. Otherwise dry weather will prevail over much of the
central California interior this week. Temperatures will average
slightly above normal through the end of this week.
.DISCUSSION...The low pressure system which crossed southern
California overnight is now over northeastern AZ and is continuing
to move east and away from our area. A dry northwest flow behind
the departed low now prevails over central CA. Some residual
moisture remains over the higher elevations of the southern
Sierra Nevada where there is sufficient CAPE and instability for
another round of afternoon convection although the extent of
thunderstorm coverage is expected to be much less than on Monday.
A few showers and thunderstorms have already been noted from
radar composites near the southern Sierra crest.
Meanwhile, temperatures are running several degrees above yday
across the southern Sierra Nevada as a result of less morning
cloud cover while temperatures have been generally running 1-3
deg F warmer. The 12Z wrf is indicating a dry upper ridge will
amplify off the Western CONUS coast tonight and Wednesday.
Temepratures are expected to continue their upward trend on
Wednesday and with less moisture expected over the southern
Sierra Nevada, afternoon convection will be limited to the higher
A shortwave trough is progged to drop into the Great Basin on
Thursday which will allow for a dry westerly flow to undercut the
offshore ridge and stream into central CA. This will push any
residual moisture over the higher Sierras well to the east of our
area. A weak shortwave will push the area on Friday and bring
slightly cooler temepratures to the region for the weekend.
The medium range models are is fairly good agreement in building
a dry ridge over the southwestern CONUS early next week while a
rex block becomes established near 140W. This will result in a dry
southwest flow prevailing across our area for the first half of
next week. Temperatures will be slightly above normal with RH
progs indicating a dry airmass prevailing.
.AVIATION...Scattered thunderstorms can be expected over mainly
the higher elevations of the Sierra between 19z today and 04z
Wednesday. Smoke from wildfires will reduce visibilities to MVFR
in some areas. Otherwise, VFR conditions will prevail over the
central California interior during the next 24 hours.
.AIR QUALITY ISSUES...please see SFOAQAHNX
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.