WELCOME TO ONLINE WEATHER STUDIES - The Daily Summary file will describe the current weather pattern across the U.S. Additional Supplemental Summary Information Files will provide optional background material, when appropriate.
The following discussion is based upon a review of the surface weather map for late Monday night. Several major weather features appeared:
SEVERE WEATHER MOVES EASTWARD -- The line of severe thunderstorms preceding the advancing cold front moved eastward through the Southeast on Monday. This system of thunderstorms spawned nearly two dozen tornadoes from northeast Arkansas into middle Tennessee on Sunday night. Tornadoes near Jackson, TN were responsible for seven fatalities and at least 50 injuries. Extensive damage was also reported.
By dawn, the strong thunderstorms stretched from Tidewater Virginia southward through the eastern Carolinas into the Florida Panhandle east of Tallahassee. Large hail and damaging winds were reported across Kentucky, West Virginia, Maryland, Alabama, Georgia.
During the day, strong winds gusted to 71 mph in western Pennsylvania, with wind damage reported near Pittsburgh. Two confirmed tornadoes and a possible third tornado were reported in south central Pennsylvania near Bedford. Some damage was reported. Severe thunderstorms moved through the New York City metropolitan area late on Monday afternoon, producing wind gusts exceeding 50 mph. Heavy rains also accompanied these thunderstorms. Because of these rains and the ice jams that developed along the rivers, flood warnings were posted for various rivers in Pennsylvania, New Jersey and southern New York State.
Because of the strong winds between 39 and 54 mph that continued to surround the storm system, gale warnings were posted on Monday for coastal waters from Sandy Hook, NJ to Eastport, ME, to include all bays and sounds.
WINTRY CONDITIONS ACROSS THE UPPER MIDWEST -- Strong winds, with speeds reaching 40 mph, were reported across Wisconsin, Iowa, Illinois to the west of the storm system that moved from western Wisconsin toward eastern Lake Superior. Cedar Rapids, IA had a peak wind gust of 47 mph. White-out conditions produced a near-blizzard in some locations. The snow and blowing snow across eastern Iowa caused the closure of a portions of Interstates 35 and 80. As much as 5 inches of snow fell across Minnesota and northwestern Wisconsin from Sunday night into Monday morning. "Wrap around" snow flurries continued to fall across the Upper Midwest, on the west side of the departing low pressure system. This precipitation had been brought around the low pressure system by the strong counterclockwise circulation regime.
The strong winds were the result of the strong pressure gradient that developed between the deepening low pressure system and higher air pressure to the west and south of the system. Inspection of any surface analysis on Monday would have revealed the presence of this strong pressure gradient by the tightly packed isobars (or lines of equal barometric pressure) around the low pressure system, especially along the western flank over the Upper Mississippi Valley.
These strong winds were also responsible for low wind chill equivalent temperatures that fell to near zero degrees Fahrenheit across the region.
As of Monday night, snow showers continued to fall to the west of the cold front, extending across the Great Lakes region and into western New York and Pennsylvania. These snow showers are expected to continue across the region into Tuesday, but with little significant accumulation.
ICY WEATHER IN NEW ENGLAND -- The flow of warm moist air northward ahead of the low pressure system was responsible for freezing rain across interior New England and Upstate New York during the early morning hours of Monday. Cold air was trapped in the valleys such as the Connecticut and Hudson Valleys. Rain falling through this shallow cold air froze upon contact with the earth's surface, producing a freezing rain event early Monday morning.
A wide area of precipitation, primarily in the form of rain, continued across northern New England into Monday night. As the cold air moves into the region following the passage of the cold front, freezing conditions could return. Winter weather advisories were posted for northern New Hampshire and Maine for icy conditions.
MORE UNSETTLED WEATHER ACROSS THE WEST -- A sequence of storm systems continued to move toward the Pacific Northwest. One system moved inland early Monday, while the next system was poised off the coast. Additional storms appeared over the central Pacific. Heavy snow, in excess of 10 inches, fell across the high terrain of Washington State, Idaho and Oregon on Monday. Rain continued to fall across low-lying coastal sections of the Pacific Northwest. Flood warnings were in effect for several rivers in western Washington and Oregon. Snow is expected across the Cascades and the Sierras into Tuesday, as snow advisories were in effect for as much as 6 inches. Some snow should also fall in the northern and central Rockies. Snow and blowing snow advisories were posted for Colorado, Wyoming and Utah.
High winds were reported along the coast, with a report of 62 mph early Monday at Tillamook, OR. Gale warnings and heavy surf advisories were continued for most of the Pacific Coast north of Point Piedras Blancas.
WARM WEATHER CONTINUED ACROSS THE SOUTHWEST -- Record high temperatures were set on Monday afternoon at Canon City, CO (67 degrees); Goodland, KS (69 degrees); Pueblo, CO (71 degrees); and Safford, AZ (73 degrees).
FOGGY WEATHER ACROSS THE SOUTH -- The relatively clear skies and weak winds associated with the large region of high pressure over the lower Mississippi Valley should produce extensive fog across south Texas and other portions of the Gulf Coast on Monday night and extending into Tuesday. Under such weather conditions, cooling of the humid Gulf air will cause saturation of the air with respect to water vapor, followed by condensation into a dense fog with visibilities on the order of a quarter mile.
TEMPERATURE EXTREMES IN THE LOWER 48 -- The lowest temperature on Monday was one degree below zero at Aberdeen, SD, while Monday's highest temperature was 84 degrees at Naples, FL.
ALASKAN WEATHER -- A large, sprawling high pressure cell covered much of central and southern mainland Alaska on Monday afternoon. This ridge of high pressure extended to the west across the Bering Sea into Far Eastern Russia. With relatively clear skies associated with high pressure, overnight temperatures across a large portion of the interior of the state fell to close to 40 degrees below zero. Afternoon temperatures at some locations failed to rise above 30 degrees below zero in spite of sunny skies. The presence of high pressure also meant that little precipitation fell across the state. However, snow fell along the North Slope, and light snow fell at Fairbanks and over the Tanana Valley on Sunday night and Monday. Several areas of low pressure were found near the state. One broad region of weak low pressure was found along the North Slope. Another low pressure system was located to the south of the central Aleutian Islands. This low spread clouds and some light snow across the central portion of the Aleutian chain. A third strong low pressure system located along the British Columbia Coast south of the Queen Charlotte Islands was responsible for windy conditions across much of the Panhandle and southeast Alaska. The strong pressure gradient between the high pressure cell across interior Alaska and the low over British Columbia was responsible for some strong winds from the east along the Gulf of Alaska coast, especially at those locations where the winds were channeled through mountain passes. For much of Monday winds at Seward gusted between 30 and 35 mph, while at Whittier, winds gusted to 58 mph.
The state lowest temperature on Monday morning was 42 degrees below zero at Northway, Noatak and Selawik. The highest temperature across Alaska as of midafternoon on Monday was 37 degrees at Metlakatla.
HAWAIIAN WEATHER -- Pleasant weather, with relatively cloud-free skies and light winds, should continue across the islands through Wednesday as a large high pressure system to the north of Hawaii should remain relatively close.
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast
Return to Online Weather Homepage
Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 1999, The American Meteorological Society.