That April dip was worrisome because the previous three years had strong first quarters followed by weak springs, said Jeff Schuster, LMC forecasting boss.
"This is the time of year when the automotive industry holds its collective breath [but] the current pace suggests full steam ahead for the second half of 2013," Schuster said in a statement today. "Economic and market headwinds have been minimized while demand continues to build momentum."
Both companies expect overall May volume to exceed 1.4 million units, which would be up 9 percent from a year earlier. April's sales rate fell despite a 9 percent increase in unit sales.
In addition, LMC/Power forecasts a retail sales rate of 12.5 million, compared with 11.5 million a year earlier.
On Wednesday, Wells Fargo analyst Richard Kwas forecast a May SAAR of 15.1 to 15.2 million but noted upside potential "given the spiffs set for Memorial Day weekend."
Kelley Blue Book, meanwhile, said a holiday boost would lift monthly sales by 6 percent, for a SAAR of 15 million.
Analysts also found other encouraging sales trends.