BASIC PATTERN:
Large Scale Pattern –
- High pressure continues oriented E-W across the southern United States, most of Mexico, and Southern California. This supports easterly flow from the Caribbean and Gulf of Mexico across Mexico and into SW Mexico and the Pacific off southern Baja California. Moisture, waves, and cyclonic circulations cross Mexico, and redevelop as tropical cyclones near SW Mexico and southern Baja.
- Tropical moisture influx into California has been limited by strong E-W oriented high pressure. The monsoonal flow has started across eastern and at times central Arizona. Some surges will start to approach the SE corner of California around the 5th with occasional moisture into southern California from the 7th through the 11th.
- A trough will bring light rain to northern California on the 3rd with cooler than normal temperatures. Otherwise the westerlies will be weak, especially Jul 5-15 with high pressure building. As high pressure builds some monsoonal moisture edges more west likely into SE and southern California.
- Still very dry across most of California with some monsoonal showers into southern California early in July and edging into central and the mountains of northern California by the middle and end of July.
- Subsequent dry cold fronts will tend to raise the fire risk as hot daytime temperatures combine with gusty dry winds to start the fire season.
- A cold sea surface temperature anomaly persists along the coast of Central California south to northern Baja California. This will encourage recurrent fog and drizzle events in the coastal forests of N California, and usual night/morning fogs for coasts of central and S California.
- The best chance for anomalously hot weather in July is in N California, from the Bay Area to Yosemite NP northward. Conditions favorable for fire starts and growth will be in the Sierra foothill areas from Tehama County south along the Sierra west slope due to dry winds with low relative humidity, and an increase in dry lightning as we progress through July and into August as the summer monsoonal moisture moves into these regions.
- For growers of avocado and other sensitive orchards and crops in the coastal hills-valleys of central and S California, watch for near seasonable occurrence of hot days, as the focus of upper high pressure is into N California, while cutoff lows with clouds and a few showers and dry lightning occur in the Central Sierras south to S California. The start of monsoonal conditions, i.e. clouds and usual mountain/desert thunderstorms is most likely by mid-July in S California inland avocado/citrus regions.
- Precipitation trend: A little light rain mainly Humboldt County to the north is possible Jul 3 as a trough moves through northern parts of the state. Other rains to follow will be monsoonal showers and thunderstorms from Approximate dates of monsoonal surges of showers in S California: Jul 7-11, 16-18, and 22-28. Showers edge into central California 24-28. Northern Calif and the central & northern Sierras could see some monsoonal showers mainly over the mountains Jul 26-28.
- Dry thunderstorms with lightning will bring an increase and early start to the fire season. High to extreme fire danger is likely by the early and middle of July.
- Tropical Cyclones: For June we have been in a wet pattern due to rains from tropical cyclones in Southern Mexico. Current CFSv2 model results suggest below normal mid-monsoon moisture in southcentral and S Mexico for July, and continuing in August. The rains in Arizona also shift below normal in late July and August.
FORECASTS FOR CALIFORNIA
Forecast for Northern and Central California:
NORCAL Rains: Jul 3-4 (Humboldt County to N), 26-28 (monsoonal showers in mtns).
CENTRAL CALIF Rains: Monsoonal showers are possible Jul 24-28 (mostly across the Central Sierras).
WARM SPELLS: Jun 30-Jul 1, 6-14 and 19-25.
COOL SPELLS: Not much cooling, cooler Jul 3-4 and 16-17.
FRONTS WITH RAINS: Jul 3. No fronts with rains after the 3rd.
Forecast for S California:
SOCAL RAINS: Jul 7-11 (scattered showers E areas), 16-18 (scattered showers), and 22-28 (better chance of showers & TSTMS).
SOCAL WARM SPELLS: Jun 30-Jul 2, 5-15 and 17-27.
SOCAL COOL OR COLD SPELLS: Little cooling with much above normal temperatures through most of the extended forecast. Slight cooling on Jul 3-4.
FRONTS WITH RAIN/DRIZZLE: Monsoonal showers start around Jul 7.
Forecast for Central Sierra Nevada:
Dates of mountain showers of rain are: Jul 18 and 24-28.
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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 June 30 - July 30, 2022
Highlights: High pressure will dominate the weather pattern in Nevada-Utah, and Arizona within through most of July. Warm to very warm and at times hot weather is expected. Model guidance is inconsistent regarding trends in monsoonal moisture, showery periods, and opportunities for cooling. Monsoon considerations: Both short-term climate models (NMME and CFSv2) are suggesting a near normal precipitation in July and Drier than normal conditions in August.
Looking Ahead – Long Range Outlook
July 30-Aug 30, 2022... NORCAL and Central California: Becoming consistently 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 end of June, and most of July, 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-July and reach a peak in the monsoon season mid to late July to early August.
For SOCAL: Progressive trend towards above normal temperature. There is potential to turn hot and dry in early-mid-July just prior to monsoonal thunderstorm rains in the mountains. Foothill and coastal valley highs m90s (avocado areas), but intermediate valleys persistently into the m90s to m100s on occasion. Monsoonal moisture increases in mid-July. Best chance for monsoonal showers and thunderstorms in mid-July through early-August.
(Terms and Definitions Used In This Weather Outlook)
Alan Fox & Zane Stephens...Fox Weather, LLC
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