Marine Weather and Tide Forecast for Fresno, CA

FXUS66 KHNX 171833 AFDHNX

Area Forecast Discussion National Weather Service Hanford CA 1133 AM PDT Thu Jul 17 2025


DISCUSSION

KEY MESSAGES...
1. Cooler afternoon temperatures with a slow warming trend going into the weekend.

2. Relative Humidity increasing over the region today and into the weekend.

3. Showers and thunderstorms developing across the Sierra Nevada Crest with a 10 to 30 percent chance Today through Saturday.

4. Probability of precipitation amounts of less than a tenth of an inch (< 0.10 inch) are about 90% with showers or thunderstorms today, but wetter showers and storms are expected on Friday with a 40% probability.

5. Slightly cooler temperatures and breezy conditions possible for the middle of next week, with some fire weather concerns.

DISCUSSION...

The region remains at least partially under the influence of an upper level ridge over the four corners region. A weak area of low pressure moving slowly north along the coast of the Baja Peninsula was allowing for increased precipitable water and humidities across the valley. Through today and into Friday, humidities in eastern Kern and into portions of Kings and western Tulare county may see this RH increase thanks to the approach of the low along the Baja.

In general, the pattern will allow for similar temperatures as yesterday with highs this afternoon in the mid 90s as Short- Range ensemble Probability of Exceedance (PoE) of reaching 100 degrees is less than 10 percent. PoE of reaching 95 degrees today again is in the 70% to 90% range for areas in and south of Fresno County allowing for high forecast confidence is seeing 90s this afternoon. With regards to winds, while PoE of reaching and exceeding 35 mph is low, will see a light afternoon breeze over the ridges and passes today.

Probability of Thunder percentages remains low today, generally from 2-8% this afternoon similar to the convection that occurred on the crests yesterday. An isolated storm may progress farther west from the crest towards the foothills than occurred yesterday, but chances again are on the low side. More organized showers and isolated storms will wait until Friday and into the weekend associated with the area of weakness/low pressure over Baja California. As the low progress north into southern California moisture will surge into the area. Increasing thunderstorm threats over the Sierra Nevada Crest and light winds can be expected during the afternoon and evenings Friday (Probability of Precipitation and Thunder (PoP&T) indicates a 30% chance on Friday) and Saturday with 10-18% probability of convection though only isolated (10-30%) chances for any storm to produce more than 0.10" of precipitation.

As previously mentioned, ensemble precip-water analysis shows higher values overtaking Central California. Yet, uncertainty still exist on the amount of moisture as convection may remain on the drier side. Due to the northward push of monsoonal moisture this week, thunderstorm will be on the drier side and raising fire weather concerns. Thunderstorms will linger on Saturday before clear skies develop on Sunday and continue into early next week.

Along with increased moisture, a slow warming trend through Sunday with Ensemble PoE of temperatures will see a slow increase as widespread values struggle to reach 100 degrees until Saturday. By Saturday, PoE of 100 degrees will only range from 20% to 60% with the higher end along the West Side of the San Joaquin Valley. Sunday will see even higher percentages as confidence increase toward those values.

Ensemble clusters are in good agreement with a trough making its way onshore by the middle of next week, though one cluster does persist the ridge over the four corners. This would allow for two things, one, the warm up through the weekend will be short-lived as the disturbance cuts into the ridge pattern.
While higher uncertainty exist in the magnitude of cooling and wind speeds for Monday, will see some change as longer range ensemble upper-air analysis leans in the direction of introducing a trough through the Pacific Northwest early to middle next week. Of note with this would be the potential noted in the ensembles/clusters for unseasonably breezier conditions Tuesday and Wednesday which may allow for gusts from 15 to 20mph on the valley floor and increased winds on the ridge tops and crests during that time frame.

AVIATION... 18Z Update:

VFR conditions will prevail for the next 24 hours across the Central California Interior. Surface winds will remain northerly from 5-12kts becoming light and variable after sunrise on Friday.

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.
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