The unprecedented outperformance of U.S. equities compared to international stocks will not last, according to one team of analysts on the Street. 

JPMorgan Chase & Co. issued a note Tuesday forecasting that emerging markets () and value assets will stage a comeback, while expecting the dollar's recent strength to subside. JPM strategists Marko Kolanovic and Bram Kaplan foresee continued strength in the U.S. equity market, yet expect it to lag behind other markets. In a more bearish and less likely scenario, the dollar's strength could continue to rise and U.S. shares could fall, according to the analysts. (See also: Take Caution With Emerging-Market Stocks: Goldman.)

"The more likely outcome is a ‘risk on’ convergence, given decent global growth, cheaper valuations outside of the U.S., a continuation of U.S. buybacks, intensified criticism of rate hikes and a strong dollar by the U.S. administration, new stimulative measures in China, and ongoing negotiations to resolve the trade war," wrote the JPM strategists. They expect this trend to be bolstered by declining liquidity and a short squeeze in currencies, metals, broad EM equities and China stocks. 

EM, Europe Equities 'Will Catch Up'

“In other words, something will give—either the US will fall or EM and Europe equities will catch up and move higher,” wrote JPM. 

While a "risk off" scenario is less likely, it shouldn't be dismissed, noted JPM. Potential catalysts include a continued dollar rally, or a breakdown in China trade negotiations. 

Thanks to a strong domestic economy, a soaring tech sector and a rising dollar, U.S. equities have fared much better than their global peers. While the S&P 500 Index has gained 7.1% year-to-date (YTD), the Bloomberg EMEA World Index has fallen 3.5% over the same period. 

"Given that this is such a rare occurrence—has never happened for both Europe and Asia—it suggests to us this is a market condition that will not persist,” wrote the strategists. (See also: 7 Global Blue Chips for a World of Rising Turmoil.)