textproduct: San Joaquin Valley

KEY MESSAGES

1. Below Seasonal Average Temperatures will exist across the region through the weekend. A slow rise in temperatures begins near the middle of next week.

2. Precipitation chances increase by this weekend with the best chances of precipitation early next week.

DISCUSSION

As someone who looks forward to cooler temperatures every year, these incoming troughs are a welcomed sight. September 1st marks the start of meteorological fall and it will certainly feel like fall. The trough off the coast of CONUS is continuing to come on shore and with it, the cooler temperatures. People may notice more cloudy conditions, especially in the northern portion of the CWA. This is because the trough has associated precipitation which is falling in NorCal. The Central Valley is not expecting any rain with this trough. Temperatures will continue to be below normal as this pattern continues through at least Saturday. Normal temperatures for the first week of September are around the mid 90s. There is essentially a 0% Probability of Exceedance (PoE) for any location in the San Joaquin Valley to be above 95 degrees. Wednesday, Thursday, Friday also have a PoE of 90 degrees at 0%. The PoE of 88 degrees for the same time frame is ranges between 30-45%, with the most likely day of exceeding 88 degrees being Thursday. The PoE of 83 degrees on Wednesday, Thursday and Friday range from 60-80%, with Thursday again being the most likely day for temperatures to exceed 83 degrees. Therefore the San Joaquin Valley can expect temperatures to be up to 13 degrees below normal.

Looking into the holiday weekend, there are signals that temperatures will continue to be below normal and there will be a chance for precipitation! Maybe rain on labor day weekend isnt everyones idea of finishing out summer, but this meteorologist loves the rain. The trough coming through will bring precipitation chances starting Saturday and into Sunday. There is currently a 18-36% chance of at least 0.10 (wetting) rain on Sunday, with the best chances being out in the Mojave Desert. Tropical Storm Marie continues to be forecasted to not have a direct impact on the Central Valley and Southern California. It may give a little bit of moisture as it passes by the trough.

Looking into the longer term, troughing continues to be the dominant feature. The Climate Prediction Center has the Central Valley in the near normal temperatures in the 6-10 day outlook and has above normal (33-40%) precipitation. In the 8-14 day outlook, the trough may weaken and allow for warmer temperatures to prevail, as most of California is in the leaning above normal (33-40%) for temperatures. It is a similar situation for precipitation as most of California is leaning above normal.

AVIATION

VFR conditions prevailing for the next 24 hours.

AIR QUALITY ISSUES

None.

CERTAINTY

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

None.