Rainless streaks weeks or months in the making may fall this week as a big shift in the weather pattern unfolds in California and the Southwest.
Slow-moving low pressure, still well off shore as of Sunday, could serve up some weather surprises as it begins sparking widely separated showers and thunderstorms as early as Tuesday.
To be clear, odds for any widespread soaking rain are very low, as this weather system will begin with limited stores of moisture.
The offshore low will take a track to the east and southeast, ending up near the Southern California coast by Thursday.
Monday, little in the way of rain will fall, as the low will still be over open water off northern California.
Tuesday, as the weather system drifts nearer to the coast, scattered showers will begin to be sparked in the west, and a few thunderstorms along and near the Sierra Nevada.
Wednesday and Thursday, the low will gain access to moisture from northwestern Mexico. Showers and thunderstorms are likely to increase at this time over the southern half of the state, throughout the Sierra Nevada and into Nevada.
Furthermore, scattered thunderstorms may break out eastward to Utah and northern Arizona on Thursday.
Notwithstanding limitations to rain-generating moisture, this low pressure area will have enough vigor to gin up a few strong thunderstorms with localized downpours, powerful wind gusts, even hail, Wednesday and Thursday.
For most Californians, it would be the first rain to speak of since late spring or early summer.
No measurable rain has fallen in downtown Los Angeles since July 12, for instance. San Franciscans have to look back to June 4 to find the last measurable rain. In Fresno, one most go all the way back to April, as the 26th was the date of the last rain of significance here.
Dry, even rainless, summers the rule in most of California, which has a "Mediterranean" climate.
Although the far north can turn rainy in October, most of California normally has to wait until November for the season's first widespread rainstorms.
A wet weekend is in store for the eastern United States as rounds of rain and thunderstorms move over the region.
Severe thunderstorms spawned tornadoes in major metropolitan areas, while wildfires raged in the West and flooding downpours persisted in the East.
As much of the West continues to be plagued by intense drought, the production of favorite and trendy foods may be more challenging for states operating in dry conditions.
Japan and South Korea face tropical floods into this weekend; the danger of a typhoon looms for next week.
Bertha is forecast to take a curved path near the islands in the northeastern Caribbean this weekend, then to stay off the East Coast of the United States next week.
Erie, PA (2000)
1.75" diameter hail.
A total of 5.31" of rain.
New England (1975)
"Hot Saturday" 107 degrees in New Bedford and Chester, MA All-time hottest day - 104 degrees in Providence, RI (also all-time record for state) 100 degrees in Nantucket for the first time