Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
703 PM PDT Wednesday Jul 27 2016
a ridge of high pressure will provide mostly clear skies and above
average temperatures through the week. Isolated afternoon showers
and thunderstorms are possible along the Sierra crest today and will
possibly spread into the Kern County mountains and desert by the
Discussion...updated air quality section...
Previous discussion...issued at 2:00 PM PDT Wednesday...
Discussion...a large upper ridge over the southwestern Continental U.S. And
the Great Basin remains the prevailing weather feature for our
area today resulting in another day of widespread triple digit
heat for the San Joaquin Valley, southern Sierra foothills and
Kern County deserts. Temperatures are generally trending upward
3-5 degree f above yday across these areas although the airmass
remains fairly dry which has lessened the adverse heat impacts
Meanwhile some cumulus build-ups and isolated showers have been
noticed on visible imagery near the southern Sierra crest as a
result of instability from the hot airmass and some upper level
southerly flow which has brought some tropical moisture and
provided for some lift near the crest. This has been most
prevalent in eastern Tulare and Fresno counties where there is a
slight chance of thunderstorms this afternoon and evening.
12z WRF indicating little change in airmass through Friday as the
ridge remains parked just to the east of our area. Daytime
temperatures will continue to run 7-10 degree f above normal
throughout our County warning forecast area the next two days and enough instability and
high based moisture will allow for isolated diurnal thunderstorms
near and along the southern Sierra crest on Thursday and Friday.
The medium range models are indicating that the ridge will weaken
some over the weekend. This will allow for a cooling trend to
taker place although temperatures will remain above normal and
triple digit readings will still be commonplace across the San
Joaquin Valley and Kern County deserts. Relative humidity progs are indicating
some mid level tropical moisture pushing into socal this weekend
which might allow for diurnal showers and thunderstorms over the
Kern County mountains and deserts as well as over the southern
Sierra Nevada. The medium range models continue to advertise a
fairly strong shortwave pushing into the Pacific northwest next Monday which
will turn the upper flow to the southwest. This will result in the
mid/upper level moisture being pushed east of our area on Monday
and dry weather can be expected over the higher elevations Monday
through Wednesday. Temperatures are expected to run slightly above
normal for the beginning of August.
a few cumulus buildups and isolated thunderstorm over the Sierra
Nevada, otherwise VFR conditions can be expected through central
California for at least the next 24 hours.
Air quality issues...
on Thursday July 28 2016... unhealthy in Fresno... Kern and Tulare
counties and Sequoia National Park and Forest. Unhealthy for
sensitive groups in Kings... Madera and Merced counties.
Further information is available at valleyair.Org
The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is high.
Certainty levels include low...medium...and high. Please visit
www.Weather.Gov/hnx/certainty.Php for additional information
an/or to provide feedback.