A coastal flood warning went into effect this morning for the entire coast of San Diego County and will remain in effect until Thursday afternoon, with “significant flooding” expected from unusually high tides, forecasters said.

“Numerous roads may be closed. Low lying property including homes, businesses, and some critical infrastructure will be inundated,” the National Weather Service said Sunday.

No damage had been reported in San Diego County as of Sunday morning.

The NWS also said some shoreline erosion will occur in the morning hours and that coastal residents should be alert for rising water and take appropriate action to protect life and property. High tides each day will occur in the morning and may be anywhere from 1 to 1.7 feet above astronomical tide predictions, the NWS said.

“Take the necessary actions to protect flood-prone property. If travel is required, do not drive around barricades or through water of unknown depth. Stay off of jetties and sea walls,” the agency added. “Avoid beaches during high tides. During high and rising tides, waves may run farther up the beach than expected. Stay far back from the water and never turn your back on the ocean.”

The warning also stretches into Orange County.

Away from the coast, warmer weather is expected in San Diego County through Monday before temperatures gradually cool during the middle of next week. Rain is possible as early as Friday, although the NWS says the timing and amount remain uncertain.

Along the coast, daytime highs will climb into the upper 70s to low 80s Sunday and Monday, running 5 to 10 degrees above normal. Overnight lows will generally range from the mid-50s to low 60s. Low clouds may begin returning Monday morning, becoming more likely Tuesday, according to the NWS.

In the inland valleys, highs will reach the upper 70s to low 80s Sunday and Monday, with overnight lows in the low to upper 50s. Temperatures will gradually fall later in the week, forecasters said.

The mountains will remain cooler, with daytime highs generally in the 60s and overnight lows ranging from the 30s to 50s, depending on elevation.

Daytime highs in the deserts will reach the 80s through early next week before cooler weather arrives. Overnight lows will range from the upper 50s to mid-60s.

The NWS said unsettled weather could affect Halloween weekend plans next weekend.