textproduct: San Joaquin Valley

KEY MESSAGES

1. Dry conditions continue for the next several days with near average temperatures today before temperatures cooldown to below average.

2. A disturbance dropping southeast from near Alaska will bring the next chance for precipitation in our area by this coming weekend (low confidence).

DISCUSSION

Another pleasant day across Central California as near seasonal normal conditions were felt under sunny skies. A storm pushing across the Pacific Northwest brought cooler temperatures and an increase in winds as precipitation stayed well to the north. Along with a near zero chance of precipitation across Central California in the next 24 to 48 hours, temperatures sand winds have seen a change. At this point, the Probability of Exceedance (PoE) of reaching 75 degrees is now below 10 percent (outside the Mojave Desert) going forward and into the weekend. In addition, the PoE of reaching 70 degrees falls below 70 percent by Wednesday with sporadic higher PoE values on Thursday and Friday. Otherwise, temperatures expected to remain at below normal values through the period.

Lingering moisture, while very limited, will continue to produce mist and haze across the San Joaquin Valley this week. PoE of visibility dropping to below 3 miles will only reach less than 10 percent as fog remains unlikely until the next intrusion of significant moisture.

Looking toward the extended periods, ensemble model analysis still showing a strong consensus toward a robust storm developing off Pacific Northwest Coast on Saturday. Confidence is high that Central California will receive another round of precipitation, with the expected onset late Saturday into early Sunday Morning. Will still expect the heavier precipitation progressing through Central California later in the day on Sunday.

While confidence in receiving precipitation is high, there remains model variability regarding exact accumulation totals (spread ranges from zero to higher totals). Ensemble model upper-air analysis is now indicating a split flow pattern with one piece of energy hitting the Pacific Northwest and the second aiming for San Diego/Baja California. Enough energy is expected to move across Central California as 48 hour Probability of Precipitation (PoP) of receiving a half of an inch (0.50) from late Saturday through early Monday sits at 30-40 percent across the Sierra Nevada. Therefore, precipitation at the 50th percentile will be a sure bet this weekend. The worst case scenario at the 90th percentile shows Central California receiving up to 2 inches of rain/snow (water) this weekend. We will continue to evaluate the potential for heavy (excessive rainfall) precipitation as the forecast makes adjustments from the extended period toward the short term.

AVIATION

A reduction in visibility remains possible over KMCE leading to potentially IFR of LIFR conditions from late tonight through mid-morning tomorrow. Otherwise, VFR conditions will prevail 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.