Some areas of San Diego County see light rainfall

SAN DIEGO (CNS) – Monsoon moisture was forecast to bring periods of clouds and even a chance for a stray burst of showers or thunderstorm in San Diego County, the National Weather Service said Sunday.

Showers developed over northern San Diego County earlier Sunday and left some very light rainfall in spots. The weather service predicted isolated showers through Sunday afternoon for southern San Diego County.

Additional rainfall was likely to be just a trace to a few hundredths of an inch. The maximum so far has been 0.03” at Montgomery Field, Santee and Borrego Palm Canyon.

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All that remains of the showers this morning are some passing high clouds. However, isolated light showers will be possible through this afternoon across southern San Diego County. Any thunderstorm activity is expected to remain confined to the mountains.#CAwx pic.twitter.com/WJTsCosc99

— NWS San Diego (@NWSSanDiego) August 15, 2021

Higher amounts of 0.10-0.25” were possible in the mountains Sunday afternoon, when there was a slight chance of thunderstorms. Farther north, dry weather was expected to continue, the NWS said.

High temperatures along the coast Sunday were predicted to be 74-79 degrees and 81-86 inland with overnight lows of 64-69. Highs in the western valleys will be 85-90 and 92-97 near the foothills, with lows of 65-70.

Mountain highs were expected to be 89-95 with overnight lows of 65-73. Highs in the deserts will be around 105 with overnight lows of 82-87. A strong ridge centered over Northern California and a westbound trough over Mexico was expected to keep a brisk easterly flow over Southern California through Monday, the weather service said.

Occasional clouds and increasing low-level moisture was expected to help moderate daytime temperatures, except over the high deserts, where excessive heat was forecast through Monday.

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Isolated thunderstorms are expected across the mountains and deserts each day the next few days, mainly in the afternoons. Gusty winds, brief heavy rainfall, and lightning can be expected with any storms that develop. Here are the rain chances for Sunday/Monday. #cawx #monsoon pic.twitter.com/9VeBGju9hw

— NWS San Diego (@NWSSanDiego) August 14, 2021

Later this week, a trough along the West Coast is forecast to bring a drier southwest flow aloft, and cooler weather.

On Tuesday, the winds are likely to weaken as the ridge to the north collapses and the trough deepens from the north as atmospheric moisture dries up over the mountains and deserts, forecasters said.

This will not be the case over the coastal basin though, because low pressure will be slowly developing in the mid-lower atmosphere just off the coast, the weather service said.

This flow will favor a deep marine layer and more low clouds into next weekend.