Sky & Telescope - April 2023 - 32

Eclipse Preview
southern Quebec. The northern edge of the eclipse path cuts
across the province's largest city, Montreal, while totality
lasts 3m 24s in Sherbrooke, to the east.
The weather story past Carbondale and into central Ohio
is one of increasing cloudiness, with percentages rising from
the upper 50s to the mid-70s before settling back into the
high 60s through Pennsylvania and New York State. It sounds
(and is) discouraging, but a new influence comes into play
where the track crosses the Great Lakes. It's not terrain this
time but the presence of the Lakes themselves.
As the path reaches Lake Erie, cloudiness on the central
line declines sharply, falling to under 60% at Cleveland,
Ohio, and nearly as much at Erie, Pennsylvania, and
Dunkirk, New York. The effect is found only on the southern
shores of the lakes, showing that the beneficial effect
on cloud cover comes with northerly winds. The northern
limit of the track, on the Canadian side of the lakes, does
not benefit from the lee-side clearing except downwind from
Lake St. Clair, near Leamington, Ontario. On the opposite
side of the track, the southern limit is too far from the lake
to feel its effects.
The same lake influence can be found along the southern
shores of Lake Ontario as well, along an arc from Niagara
Falls past Rochester and Oswego almost to Watertown, New
York. Northern and southern limits, away from the lake's
influence, show almost no change, lingering at 70% cloud
cover. Canadian eclipse sites, near the northern limit, are
on the wrong side of Lake Ontario and do not profit from its
Moose Jaw
Havre
Bismarck
Fargo
Pierre
Casper
Cheyenne
Salt Lake City
Denver
Grand Junction
Santa Fe
Flagstaff Albuquerque
Carlsbad
El Paso
Hermosillo
San Antonio
Chihuahua
Tampa
Jiménez
Culiacan
La Paz
Mazatlan
Durango
Nuevo Laredo
Monterrey
Saltillo
Zacatecas
Ciudad Victoria
San Luis Potosi
Aguascalientes
Tepic
Guadalajara
Colima
Guanajuato
Morelia
Tampico
Queretaro
Mexico City
Zaragoza
Jalapa
Campeche
Veracruz
Chetumal
Merida
0% 20% 40% 60% 80% 100%
Key West
Median Cloud Fraction
Miami
Matamoros
Amarillo
Oklahoma City
Fort Worth
Austin
Dallas
Shreveport
Houston
Jackson
New Orleans
Mobile
Kansas City
Wichita
Tulsa
Nashville
Memphis
Birmingham Atlanta
St. Louis
Springfield
Louisville
Richmond
Knoxville
Charlotte
Columbia
Savannah
Jacksonville
Wilmington
Charleston
Sioux Falls
Omaha
Lincoln
Des Moines
Chicago
Indianapolis
Columbus
Duluth
Ottawa
Minneapolis
Milwaukee
Detroit
Buffalo Albany
Pittsburgh
Washington
Philadelphia New York
Toronto
Portland
Boston
Quebec
Moncton
Montreal
Bangor
St. John
Halifax
St John's
Regina
influence, though the portion of the path from Belleville to
Kingston has slightly better conditions than elsewhere, with
average values of just over 60%.
Beyond the Great Lakes, the Moon's shadow bounces over
the northern limits of the Appalachian Mountains, with each
upward bounce producing an increase in cloud cover and
every valley a slight decrease. Cloud averages reach nearly
80% over New York's Adirondack Mountains on both the
central line and the southern limit. On the northern edge
of the track, the lowlands along the St. Lawrence River have
less cloud cover, running in the 65% to 70% range, with both
sides of the border sharing the benefit.
Northern New England and Atlantic Canada
Burlington, the most populous city in Vermont, is located
35 km south of the central line and enjoys 3m 14s of totality.
Montpelier, the state capital, is within 12 km of the southern
limit and sees a duration of 1m 40s.
The path continues across northern New Hampshire and
Maine, both of which are rural, with no sizable cities. Caribou,
Maine, lies within 16 km of the path's northern limit
and gets 2m 10s of totality. Located 65 km south of the path,
Maine's capital city, Augusta, sees a 98.0% partial eclipse.
Exiting the United States, the remainder of the eclipse
track runs solely through Canada. The path crosses central
New Brunswick, where Fredericton, the provincial capital,
lies 27 km from the southern limit and receives 2m 14s of
totality. Moncton, the largest city in the province, is just
Winnipeg
Corner Brook
Stephenville
32 APRIL 2023 * SKY & TELESCOPE
JAY ANDERSON, DATA SOURCE: NASA
Sky & Telescope - April 2023

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