After about a month in moderate drought, central Suffolk County has now been deemed to be in severe drought, according to the Thursday update from the U.S. Drought Monitor. The rest of the Island remains in moderate drought, the monitor’s least intense drought category.

That’s as Thursday into Friday promises to bring relief, at least for some spots, as rainfall — possibly heavy — is in the forecast.

“We need the rain,” said News 12 Long Island meteorologist Matt Hammer, noting that Long Island is more than 6 inches below its normal rainfall total for this time of year.

Normal rainfall from Jan. 1 through day-end Wednesday is 26.67 inches, but Long Island MacArthur Airport has recorded 20.41 inches, said climatologist Jessica Spaccio, with the Northeast Regional Climate Center, based at Cornell University.

Smithtown officials, citing high temperatures, on Thursday sent an alert to residents asking them to avoid watering lawns between 3 and 8 a.m.

Recent hot weather and lack of rainfall prompted the Suffolk County Water Authority to ask its customers to conserve water. The utility posted its request on its website July 20, urging consumers to “conserve water whenever possible.”

The state Department of Environmental Conservation said Wednesday in a tweet that the state “remains under a drought watch.” The tweet linked to the DEC’s posting of July 15 that said: “There are no statewide mandatory water use restrictions in place under a drought watch. However, local public water suppliers may require such measures depending upon local needs and conditions.”

Besides central Suffolk, a large section of western New York is also in severe drought, according to the monitor. The upgraded severe level means that: “crop or pasture losses likely, water shortages common, water restrictions imposed,” the monitor says.

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The Suffolk water agency asked that those using irrigation systems, residential or commercial, adjust from morning watering to evening. Most of the water used in such irrigation is from 2 to 7 a.m., the agency said; adjusting the watering times to between 9 p.m. and midnight would shift the burden.

“Keeping nonessential water use to a minimum is critical during this time of the summer, when SCWA pumps are fighting to keep up with peak demand,” the water agency said in its post.

The agency also asked customers to limit other nonessential uses, ranging from the washing of vehicles to hosing down streets, sidewalks and driveways.

Riverhead Town Supervisor Sean Walter is asking residents and business owners to cut back on watering lawns through the next month. Walter said in a news release earlier this week that the Riverhead Water District had implemented an odd-even day lawn watering schedule.

Walter said he asked residents and business owners to cooperate, but fines would not be imposed for violations. He said he expected the alternate-day watering plan to be in effect through the end of August “if the summer continues the way it has been.”

With Lisa Irizarry