Some portions of the Northeast have a chance at vibrant fall foliage based on forecast weather, while drought-stricken parts of the country may not have much of a display.
Warm and wet weather through the remainder of September and into the first couple of weeks of October would not be good news for leaf-peepers in the Northeast, according to Dr. Marc Abrams, a professor of Forest Ecology and Physiology at Penn State. Abrams began observing how weather conditions affect fall foliage 25 years ago.
A late and muted peak in fall colors would be expected if warmth continues into the second week of October.
Instead, Abrams added, ideal weather for a colorful fall would be drier weather through the remainder of September with colder temperatures, dipping into the 30s at night.
"A frost helps to bring out the color. What happens is that the chlorophyll - which causes the green color of leaves - starts to break down. This basically exposes the other pigments like red and orange," Abrams said. On the other hand, persistent warm and wet weather would extend the growing season, causing leaves to stay green.
A frost and freeze is most likely for upstate New York and north-central portions of New England during late September, according to AccuWeather Lead Long-Range Forecaster Paul Pastelok. This region will have the best chance for a bright and colorful fall.
While nights can get cool farther south, temperatures are not predicted to get cold enough to produce a frost before October, Pastelok added. For the big cities along the I-95, including New York City to Washington, D.C., the central Appalachians and Ohio Valley, the mild weather may mean a late peak of fall foliage with subdued colors.
Typical peaks in fall foliage color across the U.S.
While warm, wet weather limits the bright color display of leaves, the opposite - abnormally dry conditions - can also have a negative impact. Drought conditions can impact the leaf size, vigor and physiology, and exceptional droughts can even kill trees.
Hard-hit drought areas of the Midwest and Plains, especially Iowa, Nebraska and Missouri, are probably not going to have a good display of fall foliage this year, Abrams said.
The red color on the U.S. Drought Monitor map shows extreme drought conditions, while the deep red shows exceptional drought conditions (the highest level of drought).
Extreme to exceptional drought conditions are gripping much of the nation's heartland.
Fall will make an early debut across the Northwest as October-like chill spreads across the region for the first week of September.
Even so, for the main population centers such as London, Birmingham and even Glasgow, it will be far from a washout.
While Hurricane Ignacio is expected to pass north of Hawaii early this week, the island chain will not be able to escape all of the impacts.
Fred became the second hurricane of the 2015 Atlantic season and will blast the Cape Verde Islands early this week.
Typhoons and building drought will impact more than one billion people in southeastern Asia this fall.
The combination of moisture from Erika and a non-tropical system will drench areas from Florida to the Carolina coast through Tuesday.
Milwaukee, WI (1988)
Hottest summer on record. Six days of 100 degrees or greater and 36 days of 90 or above. Average temperature of 73.8 beat the old record of 72.8 set in 1921 and 1955. The normal average tempera- ture for a summer in Milwaukee is 68.3 degrees.
Washington Co., IA (1897)
Hail fell and drifted in piles 6 feet deep in Washington County.
Yuma, AZ (1950)
123 degrees - hottest temperature ever in Yuma. Yuma is the hottest city in the U.S.