BASIC PATTERN:
Large Scale Pattern –
- We note that the sea surface temperature anomalies and IVTinit continue a warm moist pattern across the Pacific from 170W to 130W…30-35N. There is some support now for troughing from the N California coast WSW-ward towards Hawaii. Beyond that statement, the pattern is not strong enough to look encouraging for a return to wet conditions for the late winter in California.
- That said, the CFSv2 monthly outlook for precipitation suggests a return to near or a little above normal rainfall for northern and northcentral California. Southcentral and Southern California from San Luis Obispo County south appear dry, and there does not appear much hope for a return to wet conditions.
- The effect of somewhat weak cyclogenetic support near the California coast (IVTinit), appears to be mostly focused into Northcentral California, including The Bay Area and spotty into S California. Feb appears to be the last month for near or above normal rainfall in central California and Sierras.
- Precipitation Trend: Rain dates in Feb: 5-6, 9, 13-18, 21-27.
- In Feb 2023, from NMME and CFSv2 models, there is a tendency for below normal temperature in N California. Above normal precipitation occurs in Humboldt-Del Norte Co’s of NW California, and the northern mountains area (Siskiyou’s), and N Sierras. Consistently dry conditions are suggested for S California.
- March 2023 looks currently (from NMME Model) colder than normal, but with a chance for about normal snowfall for the NORCAL mountains, including N Sierras, NORCAL coastal mountains, the NE Plateau, and N Sierras per the NMME model.
- Precipitation anomaly drifts back to near normal in Apr and May. It should be remembered that there is usually not much rain volume from those end-of-season rains, however welcome they may seem. Recall that for drought-related moisture deficits produced by multiple dry seasons in a row, a true drought-breaking wet period may take more than one or two months of high rain amounts in moisture. A wet month or even a wet season may kick a dent in a drought, while not addressing or breaking deficit that is multi-seasons in the making.
FORECASTS FOR CALIFORNIA
Forecast for Northern and Central California:
Norcal PRECIPITATION: Feb 5-6, 11-13, 15-18, 20-21, 24-25 and 27-28.
Norcal MILD SPELLS: Feb 23 and Mar 2-5.
Norcal COOL SPELLS: Feb 5-7, 9-22 and 24-Mar 1.
Norcal FROSTS/FREEZES: Feb 7-8, 10, 14, 19, 22-23.
Central Calif PRECIPITATION: Feb 13, 16-19, 20-21 and 25.
Central Calif MILD SPELLS: Feb 7-8, 15, 23-24 and Mar 1-5.
Central Calif COOL SPELLS: Feb 11-13, 16-22 and 25-26.
Central Calif DRY COLD WINDS/FREEZE RISK: Feb 14-15, 22-23 and 26-28.
Forecast for Southern California:
SOCAL RAINS: Feb 14, 17-19, 21-22 and 25.
SOCAL MILD TO WARM SPELLS: Feb 4-7, 24 and 28-Mar 5.
SOCAL COOL OR COLD SPELLS: Feb 13-15, 17-23 and 25-26.
SOCAL FROSTS/FREEZES: Feb 4-5, 12-13, 20, 23-24 and 26-27.
SOCAL SANTA ANAS: Feb 15, 20.
Forecast for Central Sierra Nevada:
Central Sierra Nevada Precipitation: Dates of rain or snow: Feb 9,13, 15-18, 20-22, 25 and 28.
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The listings of dates normally included for hot and cold spells, and precipitation are very approximate. They are based on our CFSDaily and CFSDailyAI products; and present expected trends in precipitation and temperature (CFSDailyAI) to 4km. Our system gives some consideration to 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 April and May 2023
Highlights: A little below or possibly near normal rainfall for SOCAL.
Looking Ahead – Long Range Outlook - April 1 - May 31, 2023
NORCAL and Central California coastal valleys, and Central Valley: In general, NMME has been appearing a little drier than the CFSv2 for California as a whole. Both NMME and CFSv2 select a warmer than normal period during the first half of Apr for northern and central California.
For SOCAL mountains westward to coast: This period currently appears about normal temperature in Apr for SOCAL even though Northern California is warmer than normal for early Apr. Precipitation in mountains and deserts: Below normal for most areas except near normal in some mountain spots. Watch for above normal temperatures in Apr, warm days but about normal nighttime temperatures in SOCAL.
(Terms and Definitions Used In This Weather Outlook)
Alan Fox & Zane Stephens...Fox Weather, LLC
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