BASIC PATTERN:
Large Scale Pattern –
- On 14th, dry hot upper high pressure builds across northcentral to S California with continued hot weather. Another trough develops on 16-19th in N and Northcentral California with minor cooling.
- Tropical cyclone influence will bring a return of hot upper high pressure during 20-26th. Rains are minimal if any for N California, but will tend to focus into SOCAL during 23-26 in the form of scattered showers and TSTMS.
- During August, showers and TSTMS develop early in the month and again about midmonth, focusing on SOCAL and Arizona.
- Cool and moist conditions in the mountains (N Sierras and coastal ranges) have helped to maintain a quiet fire season thus far in N California. However, now we have entered midsummer heat and thunderstorm (TSTM) season, with dry fuels (grasses).
- Looking to the fall, the best chance for above-normal normal rainfall will be in coastal Oregon during November, most likely within the period 11th onward, and into early December. CFSv2 guidance is tending to show above-normal rainfall in November and December 2022 for Oregon coast northward, while it is dry in Oct through most of Dec in California. Warmer than normal conditions are currently indicated through the Fall from September through November, and into December.
- Precipitation Trend - Showers July 5 in northern mountains, and north coast, then mainly dry through the remainder of July. A chance for showers and TSTMS is suggested for August (10-13th), consistent with development of the usual mid-summer (August) monsoonal rains.
FORECASTS FOR CALIFORNIA
Forecast for Northern and Central California:
NORCAL Rains: Aug 17-20.
CENTRAL CALIF Rains: Aug 16-20.
WARM SPELLS: Jul 13-28, Aug 3-8 and 11-15.
COOL SPELLS: No cool spells are expected.
Forecast for S California:
SOCAL RAINS: Jul 23-25, Aug 1-3, 6-10, 14-18.
SOCAL COOL OR COLD SPELLS: 7/14-16. 7/18-28, 8/1-7 and 8/10-13.
Forecast for Central Sierra Nevada:
Dates of mountain showers of rain: Jul 22 (central Sierra), 23 (north and central), 24-25 (north and central), 31- Aug 2 (central Sierra), 5-8 (north and central Sierra) and 13-17 (north and central Sierra).
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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 July 14 – August 14, 2022
Highlights: Hot weather with upper high pressure will continue through late July and August. Monsoon considerations: Both short-term climate models (NMME and CFSv2) are suggesting minimal trend toward near-normal precipitation in July and August.
Looking Ahead – Long Range Outlook
August 14 – September 14... NORCAL and Central California: Warmer than normal in July, with some hot conditions (highs in the mid-90s to mid-100s during the hot spells. For the coastal hills, above-normal temperatures are expected for August, away from the marine layer influence zone, with a well-established, although shallow marine layer. Some monsoonal showers should move into N and Central California mountains (Sierras and NE Plateau region and Cascades/Siskiyou’s by mid-August, and reach a peak around 13-17 August.
For SOCAL mountains westward to coast: Above normal temperature. There is potential to continue hot and dry. Foothill and coastal valley highs m90s (avocado areas), but intermediate valleys persistently into the m90s to m100s on occasion. Monsoonal moisture increases in mid-August. Best chance for monsoonal showers and thunderstorms in mid-August from both climatological and CFSv2 daily trends.
(Terms and Definitions Used In This Weather Outlook)
Alan Fox & Zane Stephens...Fox Weather, LLC
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