Undated (AP) _ April showers were in store for much of the nation today, and rising temperatures were in the offing.

When the showers clear out, forecasters predicted, temperatures would climb into the 80s and 90s in the South and into the 70s throughout the rest of the country.

The south-central United States, pounded by thunderstorms Thursday, faced more of the same today. Small hail fell in parts of Nebraska and Texas on Thursday, and recent heavy rains caused some flooding in parts of Oklahoma.

The National Weather Service warned that severe flooding could occur in Okmulgee County, Okla., as the Deep Fork River rose toward an expected crest Saturday of 7 feet above flood level.

A flood warning also was posted for Beaver Creek in northern Texas, which was nearly 3 feet above flood stage and rising.

Showers and thunderstorms Thursday extended over parts of Oklahoma, Texas, New Mexico, Colorado, Wyominc, Nebraska and South Dakota.

Heavy thunderstorms were expected today in the southern Plains and from eastern Texas to Missouri. Scattered showers were predicted for the South and the Tennessee Valley and from Illinois to Maine.

Showers also were to prevail in the West, with thunderstorms possible across the Coast Range and the Sierra Nevada.

High temperature for the nation Thursday was 91 degrees at Borrego Springs, Calif.

Other reports at 4 a.m. EDT:

-East: Albany, N.Y. 46 partly cloudy; Atlanta 57 cloudy; Boston 42 cloudy; Charleston, S.C. 59 partly cloudy; Chattanooga 59 cloudy; Cincinnati 59 cloudy; Cleveland 58 cloudy; Detroit 54 partly cloudy; Hatteras 48 fair; Jacksonville 63 fair; Key West 76 fair; Knoxville 54 partly cloudy; Macon 57 cloudy; Miami 74 fair; New York 45 partly cloudy; Philadelphia 43 cloudy; Pittsburgh 57 cloudy; Portland, Maine 39 partly cloudy; Richmond 47 cloudy; Tampa 66 fair; Washington, D.C. 50 cloudy.

-Central: Birmingham 58 partly cloudy; Bismarck 43 fair; Chicago 52 hazy; Denver 46 partly cloudy; Des Moines 56 showers; Indianapolis 53 cloudy; Kansas City 61 cloudy; Little Rock 62 foggy; Louisville 62 cloudy; Memphis 62 cloudy; Nashville 60 cloudy; New Orleans 69 foggy; North Platte 40 foggy; Oklahoma City 59 thunderstorm; Omaha 57 foggy; Rapid City 48 fair; St. Louis 60 cloudy; Minneapolis-St. Paul 46 foggy; Sault Ste. Marie 40 cloudy; San Antonio 70 cloudy.

-West: Albuquerque 46 fair; Anchorage 42 fair; Boise 62 partly cloudy; Casper 42 fair; Fairbanks 41 rain; Great Falls 47 fair; Honolulu 75 cloudy; Las Vegas 68 partly cloudy; Los Angeles 60 cloudy; Medford 53 cloudy; Pendleton 55 rain; Phoenix 73 fair; Portland, Ore. 54 rain; Reno 49 partly cloudy; Salt Lake City 51 fair; San Diego 61 cloudy; San Francisco 55 drizzle; Seattle 52 drizzle; Spokane 53 cloudy.

-International: Calgary 57 partly cloudy; Montreal 43 partly cloudy; Ottawa 50 cloudy; Regina 45 fair; Toronto 52 showers; Winnipeg 46 fair; Mexico City 59 fair; Acapulco 81 fair.