National Weather Service - Discussion
Area Forecast Discussion
National Weather Service - San Joaquin Valley / Hanford, CA
Issued: Wednesday, June 3 2020 - 2:52 AM PDT
SYNOPSIS... Well above normal afternoon temperatures can be expected over the region during the next few days with a return of triple digit heat in the San Joaquin Valley, lower foothills and desert today and Thursday. Isolated afternoon thunderstorms are possible over the high Sierra Wednesday and Thursday. A cooling trend will begin Friday accompanied by showers and isolated thunderstorms over mainly the higher terrain. The weekend will be much cooler with gusty winds.
DISCUSSION... Closed upper level low pressure centered off of Baja California has been streaming mid and high level clouds over the region for the past several days. The clouds have been wreaking havoc on the Max temperature forecast for the past couple of days and yesterday was no different. Many areas in the SJV where the clouds were, barely broke 90 degrees. However, areas to the north where it cleared out were in the mid to upper 90s. It was 94 at Los banos and 91 at Bakersfield...very unusual temperature pattern. Unless you have cloud cover.
The upper low is drifting west and is expected to take its clouds with it today. So I have a bit more confidence with the Max temperatures today and tomorrow. Tomorrow looks to be the hottest day as the four corners ridge will build west and heat us up. Guidance has been running warm but it has been consistent with the forecast over the past several runs. We are seeing a surge of moisture that will impact the Sierra today with showers and thunderstorms this afternoon. We are seeing the showers and thunderstorms waning on Thursday and increasing again on Friday.
Once we get through the next couple of days and the hot spell over the region, we can look forward to a significant cooldown by Sunday. At least a 25 to 30 degree swing from high temperatures on Thursday to high temperatures on Sunday will remind us that it is still spring in the Central California Interior. Friday we will see the front pushing through later in the evening and we will see an increase in showers and thunderstorms...mainly in the Sierra and even in the Kern mountains. We will also see an increase in winds across the coastal range and through the Kern county mountains that will continue into Saturday and possibly Sunday. A rapid warming trend is expected early next week as we see Max temps rise from the mid 70s in the SJV on Sunday to back into the mid 90s by Wednesday. It is expected to be dry early next week as an upper level ridge builds back in to the region. The rollercoaster ride of hot to cool back to hot again is pretty normal for this time of year. But at least the hot spells are short this time of year. Next couple of months will be a different story.
AVIATION... VFR conditions can be expected throughout the central California interior during the next 24 hours.
AIR QUALITY ISSUES... On Wednesday June 3 2020... Unhealthy for sensitive groups in Fresno and Kern 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 medium.
Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback.
HNX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 2 PM this afternoon to 7 PM PDT Thursday for CAZ180>189.
Heat Advisory from 2 PM this afternoon to 7 PM PDT this evening for CAZ179.