Large Scale Summary
- The longwave pattern supports a near term tendency for strong warm upper high pressure, with anomalously dry and warm conditions. After 20th there will be a tendency for occasional troughs near the California coast between the Bay Area and SE California, and also farther southwest out at 20-30N 155-135W. SSW flow is well west of California at 140-155W. Mostly weak troughing is supported in the subtropical North Pacific in agreement with the IVTinit pattern.
- The important factor to consider is that troughing in the subtropics will tend to affect prevailing patterns in the jet streams further north. Specifically we are looking at 30N, 40N, and 50N. Slowest westerly wind speeds will be near 40N, while more normal wind speeds occur near 50N. The greatest interruption to the westerlies will be at 30N, bordering the subtropics.
- Precipitation dates with the current pattern: Dates in March: Central Sierras are: Mar 25,28-31 and Apr 1.
- NOAA/CPC/NWS still tends toward below average precipitation in Mar and April for all of California, and below average for April in the Sierra Nevada and Central California. This includes slightly below average for the Sierra Nevada mountains from Tahoe south to about Yosemite-Kings Canyon. For ORWA, we expect below average rainfall at the coast and coastal mountains, and Oregon to northern WA state.
- Briefing for mid Mar through first part of April: in SOCAL and South-Central California: Warmer than average in Central and S California through Mar 21, then a turn to cooler than average conditions in in March. The south half of California including SOCAL appears to be warmer and drier than average. The Sierras appear to have below average precipitation but still a little warmer than average with high snow levels expected. April rainfall near average in central and S California, but slightly above average in southern-Central Sierras, and in the mountains of Southern California.
- For May 2026 we see from the NOAA guidance a tendency for mild temperatures and about average precipitation, below average in NORCAL.
Near Term Outlook
NORCAL
- PRECIPITATION DATES: March 5, 29-31, Apr 2,3, 5,7.
- MILD to WARM/DRY PERIODS: MAR 27-28
- MOUNTAIN SNOWS AND COLD: MAR 25,28-31, APR 5,7.
CENTRAL CALIFORNIA
- PRECIPITATION DATES: MAR 25, Apr 3,5,7
- MILD AND DRY: MAR 26-27
- CENTRAL SIERRA SNOWS: MAR 29-31 and Apr 1, MAR 29-31, Apr 5-7
SOUTHERN CALIFORNIA
- PRECIPITATION DATES: MAR 25, 28-31. Apr 3,5
- COLD/FREEZES DRY WINDS:FREEZES VALLEYS MAR 27-31, Mar 28-31. Apr 7-9
- MOUNTAIN SNOW: MAR 25,28-31, Apr 3,5,7
- SOUTHERN CALIFORNIA DESERTS PRECIPITATION DATES. Mar 25, then 29-31
Medium Term Outlook — APRIL - MID MAY
NORCAL
- NORCAL PRECIP Dates: MAR 25, then 29-31 Mountains. April-mid Apr 3,5,7, early May 2026
- PRECIPITATION: PRECIP MOSTLY NEAR AVERAGE IN THE EAST. BELOW IN WEST/N COAST.
- MOUNTAIN SNOWS: BELOW AVERAGE, HIGH SNOW LEVELS.
CENTRAL CALIFORNIA
- PRECIPITATION: MOSTLY NEAR AVERAGE IN SIERRAS, including late May. BELOW AVERAGE ELSEWHERE.
SOUTHERN CALIFORNIA
- PRECIPITATION: NEAR AVERAGE. BEST CHANCE SHOWERS: MID APR TO early MAY.and 29-31 May;
- SOUTHERN CALIFORNIA DESERTS PRECIPITATION: NEAR AVERAGE. BEST CHANCE SHOWERS:
MID APR TO MID MAY and 29-31 MAY.
Figures and Text: Alan Fox, Fox Weather, LLC
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