Dress lightly and keep the umbrella and rain gear handy on Sunday if your plans call for outdoor activities. Finding a lake, pool or other place to keep cool would be a good idea, too.

The combination of the season's first 90-degree temperature and high humidity levels has led the National Weather Service to issue a heat advisory for the seven-county metro area from 1-7 p.m. as the heat index — what it feels like — could approach 100 degrees.

"Summer is making an appearance," said Tyler Hasenstein, a meteorologist with the Twin Cities office of the NWS. "It will be hot most of the day."

The remainder of Saturday will remain much cooler in the metro and across southern Minnesota as steady to moderate rain continues to fall throughout the afternoon and into the evening. A few strong storms are possible Saturday night, with the greatest rain totals — possibly up to an inch — expected in the Mankato area and southward, Hasenstein said.

Oppressive conditions will overtake the southern part of the state Sunday, but only for a day, Hasenstein said. Temperatures will drop into the 80s Monday and Tuesday, with milder 70s by midweek.

The spigot that has pushed river levels high and has the metro area running about 3 inches above normal precipitation levels for the year shows no signs of turning off. A slight risk of severe thunderstorms across the southern third of Minnesota will accompany Sunday's heat, the NWS said.

Multiple rounds of moderate to heavy rain are in the forecast Sunday through midweek, with a slight risk of heavy rain from the Twin Cities north and west on Monday and from the Iowa border to Duluth on Tuesday, the NWS said.

"There is a potential for 6 inches" in some places this week, Hasenstein said, with "pretty solid range of 3 to 5 inches."

The heaviest rain is most likely on a line from Lac Qui Parle County in western Minnesota to near Duluth, "but there will be plenty of rain in the Twin Cities," Hasenstein said.

After a soggy May that brought 5.8 inches of rain to the metro, additional rain could push rivers and creeks over their banks.

"That is a concern in the middle part of the week," Hasenstein said.

Sunday's predicted high of 92 in the metro, if reached, would make it the warmest day of the year so far. The current distinction belongs to May 12, when the mercury touched 88 degrees. The Twin Cities typically sees its first 90-degree day by May 30, according to the Weather Channel.

Showers and thunderstorms remain in the forecast every day next week, the NWS said.

"It looks like it will be a wet end of the month," Hasenstein said.