WET WEATHER ACROSS THE NORTHEAST -- A complex low pressure system located along the East Coast on Wednesday night was responsible for producing widespread light rain that lasted for much of the day from New England south to Virginia. One low pressure center was located in the New York City metropolitan area, while another weaker low was situated over the Delmarva Peninsula. A nearly stationary front continued southward along the coastline.
A second storm system was located over eastern Quebec with a cold front that trailed southwestward along the Appalachians before turning westward over the Ohio Valley.
By Thursday morning these systems should have moved eastward, with the low pressure center reaching the Maritimes and northern portions of the cold front pushing offshore. Essentially all the precipitation should end across New England.
THUNDERSTORMS MOVE ACROSS THE SOUTH -- Scattered showers and thundershowers developed and moved along a cold front that extended from Virginia southward across the Deep South to west Texas. The front separates cooler air to the north from the warmer air to the south. Some of the thunderstorms became severe over east Texas and northwestern Louisiana as large hail and high thunderstorm winds were detected.
The cold front is expected to continue pushing south and eastward by Thursday morning. A slight risk of thunderstorms that could become severe should be found in an elongated region that extends from the Big Bend area of west Texas to near Atlanta, GA.
CHILLY CONDITIONS MOVE ACROSS THE MIDWEST -- A large sprawling high pressure cell pushed southeastward into the Upper Midwest from the Prairie Provinces of Canada. As of Wednesday night the center of this high was located over the Red River Valley of the North, separating the Dakotas and Minnesota. Relatively clear skies and cool air expanded southward across the Great Lakes into the Mississippi and Ohio Valleys.
On the east flank of the ridge a northwesterly wind flow across the Great Lakes produced some light lake effect snow. As much as an inch of snow fell across eastern portions of Michigan's Upper Peninsula and northern sections of the Lower Peninsula as of Wednesday morning. On the west limb of the ridge a more southerly wind flow was beginning to bring warm air northward across the western Plains.
The center of the high pressure is forecast to move southeastward, reaching northwestern Wisconsin by Thursday morning.
WARM WEATHER CONTINUES ACROSS THE NORTHERN ROCKIES -- Unseasonably warm conditions were found again across the northern Rockies on Wednesday as high temperatures were at least 20 degrees above the climatological high temperatures for the date. High pressure over the region with sunny skies and a downslope motion helped contribute to the warm weather. On Wednesday afternoon a high temperature record was set at Rawlins, WY as the temperature reached 65 degrees.
WET WEATHER PERSISTS ALONG THE WEST COAST -- Rain and high-elevation snow continued along the West Coast as a cold front nearly stalled after moving onshore. By mid evening, the front ran southward from a low pressure center in British Columbia across interior Washington State and Oregon before exiting off the coast near San Francisco Bay. As much as three inches of rain fell across northern California on Wednesday. By late afternoon, Eureka, CA had received 2.06 inches of rain since midnight, setting a daily precipitation record. Southern California received lighter amounts of rain.
The front should continue to move slowly eastward by several hundred miles by Thursday morning. The precipitation shield is forecast to remain across the Pacific Northwest. Winter storm warnings were posted for the Siskiyous and other mountains in northern California for as much as a foot of new snow. Rain should also expand southward into Southern California. Several inches of snow could fall on some of the higher mountains surrounding the Los Angeles Basin.
Ocean swells to heights of 20 feet continued along the Oregon coast. As a result, a heavy surf advisory was in effect from Cape Shoalwater, WA to Florence, OR that extended through Wednesday night.
YESTERDAY'S TEMPERATURE EXTREMES ACROSS THE LOWER 48 -- The lowest temperature on Wednesday was 7 degrees at Saranac Lake, NY. Wednesday's high was 86 degrees at Harlingen and McAllen, TX.
ALASKAN WEATHER -- A strong storm system moved across the eastern Bering Sea on Wednesday afternoon directed toward western Alaska and accompanied by wind, rain and snow. At that time, the low pressure center with a central sea level pressure of approximately 960 mb was located just to the west of Bristol Bay, with an occluded front that stretched to the southeast, crossing the Alaska Peninsula. A strong pressure gradient surrounding this storm system produced strong winds across the Bering Sea as well as the across the northern Gulf of Alaska. Winds gusted to 50 mph at Adak and Shemya, to as much as 45 mph over Bristol Bay and to 40 mph at Kodiak. A wind advisory was posted for the Anchorage Hillside and Turnagain Arm, where wind gusts reached 63 mph at the Portage Glacier Visitor Center. Rain fell along the Gulf coast from Seward to Yakutat, a mixture of rain and show fell in some of the valley as well as at Valdez and Kenai, while snow fell at Kodiak, in the Chugach Mountains and across the Alaska Range. A low pressure sytem was dissipating south of the Queen Charlotte Islands.
Farther north, a ridge of high pressure strengthened over the Arctic Ocean. As a result of the strong pressure gradient, a strong northeasterly onshore wind gusting to 40 mph produced blowing snow conditions, reducing the visibility to more or less zero from Cape Lisburne to Prudhoe Bay. As a result, a blizzard warning remained in effect for the Arctic Cost. Wind chill-equivalent temperatures along the Arctic coast fell to 40 degrees below zero.
Temperatures across the state showed a rapid increase on Wednesday, with the largest increase occurring at Northway, where the temperature rose 42 Fahrenheit degrees, from a morning reading of 1 degree below zero to 41 degrees above by early afternoon. Fairbanks experienced a 30 degree rise (from 16 to 46 degrees) and at Shismaref on the Chuckchi Sea coast where the temperature increased from 9 degrees below zero to 21 degrees above.
The state's lowest temperature was 9 degrees below zero at Deering and Shismaref. The highest temperature was 49 degrees at Ketchikan and Klawok.
HAWAIIAN WEATHER -- A ridge of high pressure located almost 1000 miles to the northwest of Honolulu maintained moderate trade winds and relatively dry weather across the islands on Wednesday. This high pressure cell will move eastward and weaken by the weekend, when a new high pressure system approaches. High surf advisories remained in effect for the north and west shores of the islands. Small craft advisories continued for all state waters.
THE CHERRY BLOSSOM WATCH -- Many tourists descend upon Washington, DC during the spring to view the sights, including the blossoming cherry trees that line the Tidal Basin along the Potomac River. The National Park service operates a website that reports the status of the cherry blossoms in anticipation of the annual Cherry Blossom Festival that is scheduled for next week. This site also has a listing of the phenological observations for past bloom dates.
RADAR PRODUCTS -- For more information describing interpretation of Online Weather radar summary products, you may consult Thursday's electronic Supplemental Summary Information .
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast
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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 1999, The American Meteorological Society.