BASIC PATTERN:
Large Scale Pattern –
- We had heavy rains in SOCAL during 27-28th! However not much rain occurred in central and N California. Despite the SOCAL rains, for the most part, the current dry pattern for California is slow to release its dry grip on N and northcentral California. Sea surface temperature-related influences (IVTinit™) are consistent in focusing the rain developments mostly west of N and Central California. Upper lows, troughs and fronts do come SE and E into California, but lack vigor.
- Precipitation trend: Approximate dates of precipitation are: showers Apr 3-4 far N mountains, showers 7,10-11, 17-18, 21.
- April: Below normal sea surface temperatures are suggested by the latest guidance from the North American Multi-Model Ensemble (NMME) for Apr – June 2022. This will tend to support risk of frost in Apr on occasion for NW California coastal valleys, including Mendocino and Sonoma Co’s, and early April in upper Salinas Valley, and San Luis Obispo Co coastal valleys. However, the combination of colder than normal sea surface along the California coast, and well above normal temperatures in inland valleys of California, including mountains and deserts, contributes stronger onshore flow and persistent or recurrent marine fog. For the north and central California coast, this encourages unusually persistent or recurrent conditions for fog drip in the coastal forests, and a normal end of the frost season in April.
- May: Turning much warmer than normal away from the coast, Including the coastal hills above the marine inversion (1200 ft), and valleys (interior Salinas Valley, Central Valley-both Sacramento and San Joaquin portions, and Delta. Again, the Redwood Coast will tend to be cool and drippy with recurrent onshore and marine layer…more fog drip than normal.
FORECASTS FOR CALIFORNIA
Forecast for Northern and Central California:
NORCAL Rains: Apr 3-4 (light), 7 (light), 10-11, 17-18 and 21.
CENTRAL CALIF Rains: Apr 11-12, 18 and 21.
WARM SPELLS: Apr 1-2, 6, 9 and 23-25.
COLD SPELLS: Apr 4, 7, 10-13, 17-19 and 21-22.
FRONTS WITH RAINS: Apr 3, 7, 10, 17 and 21.
FROST RISK: Mar 30-31, Apr 5-6, 13-14 and 19-20.
Forecast for S California:
SOCAL RAINS: Apr 13, 19 and 22.
SOCAL WARM SPELLS: Apr 1-2, 5-9, 14-17 and 24-26.
SOCAL COOL OR COLD SPELLS: Mar 29-30, Apr 4, 13-14 and 19-22.
SOCAL FROST PERIODS: Apr 14, 20 and 23.
FRONTS WITH RAINS/DRIZZLE: Apr 13, 19, and 22.
Central Sierra Nevada:
Dates of mountain rains and snows are: Apr 11-12, 18 and 21.
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The listing of dates normally included for hot and cold spells, and precipitation are based on our CFSDaily and CFSDailyAI forecast products, and present expected trends in precipitation and temperature (CFSDailyAI) to 4km. Our system gives some consideration of terrain and coastal influence. We consider the CFSv2 as one of the better ways to represent basic weather down in the sub-monthly time scale beyond the 15 day GFS or monthly maps from CFSv2 or NMME.
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Southern California Deserts Outlook for Apr 1-30, 2022
Highlights: Turning consistently warmer than normal for most of mid Apr.
Looking Ahead – Long Range Outlook
May 1-31, 2022... N and Central California: Trend toward warmer conditions. We should see a turn to higher snow levels than normal in the Sierras, and above normal temperatures for mid-Apr and May 2022. Near normal rainfall in the Delta and Northern California. Consistently warmer than normal in mid-May onward with some hot conditions (highs in mid to upper 90s possible around May 15th and onward later in the month.
For SOCAL May 1-31, 2022: Progressive trend towards above normal temperature for May, and below normal rainfall for May. There is potential to turn hot and dry in mid-May, with foothill and coastal valley highs (avocado areas) peaking into u90s on occasion before the persistent marine layer pattern gets well established.
In summary, despite a couple of upticks of rains 4th and 7th and mid-Apr in northcentral and N California, a drier than normal rainy season, overall, is likely, with some seriously low reservoir levels at the beginning of the long dry hot season. Watch for some 100+ hot spells early in the summer season for end of May and in June while cool fogs hang at the immediate coast/beach through most of the days from end of May through June.
(Terms and Definitions Used In This Weather Outlook)
Alan Fox & Zane Stephens...Fox Weather, LLC
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