Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 302135
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
235 PM PDT SAT JUL 30 2016
A ridge of high pressure continues to bring hot temperatures through
the weekend. Afternoon and early evening showers and thunderstorms
are possible along the Sierra crest each day through early next week
and will possibly spread into the Kern County mountains and desert.
Another very hot day across Central California as triple digits
will be observed again over the lower elevations of the district.
While not in the triple digits on Friday, many mountain locations
were able to reach the 90s for a warm day over much of the Central
California Interior. Minimal change today will allow for another
hot day with widespread triple digits. Even more, values expected
across the Kern County Deserts will reach up to 115 degrees, which
will warrant the continuation of the excessive heat warning. This
warning will be valid until 8 pm pdt and will be extended to
include Sunday. Based on current short range progs, Sunday will
only be slightly cooler but still very hot. The onshore gradient
from KSFO to KLAS while not very strong was starting to tighten
and will allow for slightly cooler conditions on Sunday as the
marine layer over fort ord was already reaching above 1000 feet
above sea level.
Models maintain their prog of retrograding the four corners high
westward as an upper low moves through western Canada. While
this will only flatten the upper ridge, it will open the door for
another trof to push into the region toward midweek. The second
trof is progged to move onshore over the Pacific Northwest on
Tuesday and begin influencing Central California shortly
afterwards. While temperatures will see a slow downward trend for
the next few days, the best cooling may start occurring on
Thursday as locations across the San Joaquin Valley reaching the
100 degree mark will become more isolated. Even better cooling
will occur by the end of the week and into the weekend as a deeper
trof pushes through the region.
Convection remains weak and confined to the Sierra Nevada and
possibly the Tehachapi Range today. Upper air analysis does show a
weak southeasterly flow pushing subtropical moisture into the
region. Yet, the westerly winds over most of Central California
will confine the convection to the mountains and move the blow off
east-northeastward. With little change in the air flow during the
next 24 hours, will see a similar trend in convection on Sunday.
Due to dominates of the upper ridge pattern, will see little
change in the convective coverage and maintain a slight chance of
measurable precipitation over the mountains for the first half of
the week. The latter half of the forecast period will be under the
influence of the Pac-northwest trof and begin a drying pattern.
Isolated thunderstorms are expected near the Sierra Crest until
03z Sunday and again between 19z Sunday and 03z Monday. An
isolated thunderstorm or two cannot be ruled out over the Kern
County mountains and desert through 03z Sunday. Otherwise VFR
conditions will prevail across much of the central California
interior during the next 24 hours.
.AIR QUALITY ISSUES...
The San Joaquin Valley Air Pollution Control District has issued
an Air Quality Alert due to smoke impacts in San Joaquin,
Stanislaus, Merced, Madera, Fresno, Kings, Tulare, and the Valley
Portion of Kern Counties from the Soberanes Fire. For details,
please refer to the SFOAQAHNX.
The level of certainty for days 1 and 2 is high.
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.
Excessive Heat Warning until 8 PM PDT this evening CAZ098-099.
Excessive Heat Warning from 11 AM to 8 PM PDT Sunday CAZ098-099.