National Weather Service - Discussion


Area Forecast Discussion

National Weather Service - San Joaquin Valley / Hanford, CA
Issued: Sunday, August 9 2020 - 1:29 PM PDT

SYNOPSIS...Other than isolated thunderstorms near the Sierra crest during the next few afternoons, dry weather will prevail over the central California interior for the next several days. Temperatures will average slightly above normal through the end of the week.

DISCUSSION... Very weak upper air trough circulation seen moving westward on current infrared imagery and located about 200 miles offshore over the eastern Pacific. This will allow 500mb heights to slightly increase bringing an increase in high temperatures of about 2-3 degrees above normal through Friday.

As far as mountain convection concerns go, there will continue to be a slight chance of showers and a few thunderstorms each afternoon and early evening at least through Tuesday with a bit of elevated instability with the diurnal heating/winds. The best chances for the convection will mainly be north of Tulare County along the Sierra crest. Small hail, brief heavy downpours, dangerous lightning and localized gusty winds will be the main impacts.

By next Friday, a moderately strong ridge currently centered over Texas will begin to retrograde westward into the region further increasing temperatures. At this time, high temperatures in the San Joaquin Valley will range between 102-105 degrees, in parts of the Kern County Desert temperatures up to 108 are conceivable next weekend. We will continue to monitor this heat in the coming days as the exact strength of the ridging when it arrives will determine how hot things get around here.

AVIATION... Isolated thunderstorms can be expected near the Sierra crest through 03z Monday. Otherwise, VFR conditions will prevail over the central California interior during the next 24 hours.

AIR QUALITY ISSUES... On Sunday August 9 2020... Unhealthy for sensitive groups in Sequoia National Park and Forest. Further information is available at


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 for additional information an/or to provide feedback.