KANSAS CITY, Mo. — The worst drought in decades is expected, over the next few months, to continue choking a large area of the Plains and Rockies that missed the soggy remnants of Hurricane Isaac, according to the National Weather Service’s Seasonal Drought Outlook released Thursday morning.
But those lingering rain bands from the hurricane did provide welcome moisture to the Midwestern states that were previously the epicenter of the drought, soaking states like Missouri, Illinois, and Indiana with 2 to 6 inches of rain, the Agriculture Department’s US Drought Monitor also reported Thursday morning.
Most of Missouri has been downgraded from being in exceptional or extreme drought to being in severe drought.
Almost all of Illinois and Indiana are now in the severe or moderate category.
But the drought’s severity was upgraded through much of the Central and Southern Plains — an area that stretches from southern South Dakota to northern Texas and has been suffering from triple-digit temperatures and a lack of rain. Parts of South Dakota fell into exceptional drought, and that categorization expanded in large parts of Oklahoma, Kansas, and Nebraska as well.
Forecasters say this region is moving to a climatologically drier time of the year, meaning the drought will likely intensify in the coming months.
Overall, 62.89 percent of the Continental United States remained in moderate to exceptional drought, an improvement of less than a half a percent from last week, according to the Drought Monitor.
All this has meant that, despite the heavy downpours from Hurricane Isaac, the desiccated regions of the country still had ponds too shallow to water cattle, fields too dusty for feeding, and crops beyond the point of salvage.
‘‘Isaac’s rains were like Chapter 1 in the drought-relief book,’’ said David Miskus, a meteorologist with the National Oceanic and Atmospheric Administration’s climate prediction center. ‘‘We still need a lot more rain to go here to really eliminate this drought.’’
Thick, swirling, gray bands from Hurricane Isaac drenched broad areas of crop country, from Arkansas through Missouri to Illinois, with 2 to 8 inches of rain. The rain brought needed moisture to rock-hard soil, a welcome development for farmers who will plant wheat in the coming weeks. Some pastures have started to green in the region, and the pods on some soybean plants have spruced up.
Still, a large majority of the nation’s farmland remains parched.
In Illinois, 72 percent of pastures were in poor to very poor condition this week, compared with 90 percent a week earlier, according to the Agriculture Department.
The percentage of pastures in poor to very poor condition in Arkansas dropped 12 points this week to 72 percent. But 99 percent of Missouri’s pastures remained in poor to very poor condition, despite the weekend rain.
The percentage of corn rated poor to very poor in 18 major corn-producing states stayed level at 52, which is not surprising given that much of the nation’s corn crop had been destroyed before the weekend’s rains.
The rains were ‘‘too late to bring much improvement for summer crops,’’ said Brad Rippey, a meteorologist with the Agriculture Department. ‘‘We’re kind of looking ahead now to winter wheat planting.’’
The moistened soil will help wheat germinate when it is planted, agriculture specialists said.
States like Iowa, Nebraska, Kansas, South Dakota, and Oklahoma saw very little rain from the hurricane, and with hot temperatures forecast this week, conditions could get even worse, meteorologists said. Much of these areas will remain or be upgraded to extreme and exceptional drought, Miskus said.
The stream flow — a measure of the water level in streams — returned to normal this week in many parts of Missouri, Arkansas, Indiana, and Illinois, after being rated below or much below regular levels in July, according to the Geological Survey.
While parts of Arkansas saw up to a foot of rain, the most severely affected drought areas in the northern tier did not get as much moisture, said Zach Taylor of the state’s Department of Agriculture.