Wall Street economists and money managers spent the long holiday weekend keeping close watch on the effects of Hurricane Katrina, with many saying that, despite the devastation, the long-term impact on U.S. and global economic growth should be muted.

But several analysts also warned that global stock, bond, currency and commodities markets may react sharply in the coming days and weeks to any signs of prolonged energy supply disruption, depressed consumer spending or rapidly rising unemployment.

"The economic and market implications of Katrina, and her ugly aftermath, remain highly problematic," Robert J. Barbera, chief economist at ITG-Hoenig, wrote in a report to clients over the weekend. "Most obviously, a slower trajectory for global growth now seems unavoidable. . . . U.S. consumer spending will take a hit in the months ahead."

Several Wall Street firms reduced their predictions for U.S. economic growth in the second half of the year, citing the impact of gas prices on consumer spending and the disruption of commodity shipments through the critical ports at the mouth of the Mississippi. Credit Suisse First Boston, for instance, reduced its estimated gross domestic product growth for the third quarter from 3.7 percent to 3 percent.

William C. Dudley, chief U.S. economist at Goldman Sachs & Co., wrote in a research note that the reduction in economic output should be limited to the next few months. But he said such an outcome was not guaranteed. "The worst-case scenario is if the drop in consumer spending leads to significant [enough] job losses to push the unemployment rate materially higher. That could be sufficient to generate the type of dynamics that culminate in recession."

Several analysts said that whether those dynamics emerge will depend in large measure on the pace with which oil and gas production return to normal levels. Signs of improvement should limit further spikes in oil prices and in turn ease the rise in gas prices. Positive news on Gulf of Mexico production helped ease crude oil prices in London trading on Monday.

However, analysts said any further anecdotal reports of gas hoarding or long lines at filling stations could cause panic and another sharp increase in oil and gas prices. In such a scenario, stocks would sell off quickly and Treasury bond prices, which rallied last week, would rise further.

Several Wall Street economists said any economic growth erased this year may simply be deferred to early 2006, as spending on Gulf Coast rebuilding creates jobs and pumps money into the economy. Several also predicted that Katrina's impact may spur the Federal Reserve to put its campaign of interest rate increases on hold. That could help keep mortgage rates low, extending the housing boom.

Money managers will be closely watching the municipal bond market this week. According to investment firm Cumberland Advisors, the three states hit hardest by Katrina -- Mississippi, Louisiana and Alabama -- have a combined $11.5 billion in outstanding municipal debt.

In some cases, payments to holders of those bonds are scheduled to be made by cities and counties that were badly damaged by Katrina. Some of the bonds are backed by payment guarantees from state governments. Many are backed by bond insurance firms. Nonetheless, Cumberland Chairman David Kotok said credit downgrades from the major rating agencies are likely for many bonds. Such downgrades could cause a wave of selling.

The impact could further ripple through the bond market if the companies that insure municipal bonds sell large parts of their own portfolios to raise cash to meet claims or are themselves put on negative credit watch by any of the ratings agencies.

Internationally, any significant dent in U.S. consumer spending could have a major impact, especially for Asian economies that rely on exports to the United States.

"Asia has been able to shake off higher oil prices extraordinarily well. What matters for Asia is U.S. consumer demand and the extent to which that's affected," said Amy Auster, chief international economist at ANZ Bank in Melbourne, Australia. "If gasoline prices stay high for a long time you have to assume consumption in the U.S. will soften, and that will be an issue for Asia."

The only major effect so far, Auster said, is that speculation about a pause in interest rate increases by the Federal Reserve has caused the dollar to fall against major currencies. ANZ has lowered its estimate for the dollar as a result, with the bank's forecast for the year-end shifting from 115 yen per dollar to 106 yen per dollar.

Hans Timmer, chief macroeconomic forecaster at the World Bank, said that if oil prices remain high "the biggest impact by far will be on the poorest countries" such as Ethiopia and Kenya that do not produce oil and must spend a large proportion of their output on oil imports.

Staff writer Paul Blustein in Washington contributed to this report.