WELCOME TO THE FIRST WEEK OF THE ONLINE WEATHER STUDIES PROJECT -- The Daily Weather Summary file will describe the current weather pattern across the U.S. Additional Supplemental Information Files will provide optional background material when appropriate.
Sincerely,
Ed Hopkins
WEATHER OVER THE WEEKEND -- A slow moving storm system that moved developed late Thursday night and moved eastward across the Gulf Coast States was one of the nation's major weather events over the just concluded weekend. This storm system developed in west Texas as a low pressure system near the southwestern terminus of a nearly stationary cold front that had moved southward across the Southern Plains. Early concern was that this storm system would be an unwanted guest to the Super Bowl game and festivities on Sunday night in Miami, FL. By Sunday morning the storm system was centered over the mid Mississippi Valley, with much of the precipitation stretching from the Gulf Coast north across the Tennessee, Ohio and Mississippi Valleys, reaching as far north as southern Iowa.
A large precipitation shield accompanied this system, providing an assortment of precipitation types. In the cold air to the north of the developing storm system, a combination of freezing rain, ice pellets (sleet) and snow fell across eastern New Mexico, the Panhandles of Texas and Oklahoma, and into southwestern Kansas. As much as 6 inches of snow fell at Amarillo, in the Texas Panhandle, with at least a foot reported to the west toward Tucumcari, NM. Portions of Interstate 40 were closed due to the snow. On the south and east side of the storm system, an extensive region of rain showers and thunderstorms developed in the warm, humid air drawn northward from the Gulf of Mexico.
As the storm moved eastward during Friday and into Saturday, this precipitation shield moved slowly eastward, leaving in its wake impressive rainfall totals across the western Gulf Coast and southern Plains. Flood watches and warnings were posted for many locations in east Texas, southeast Oklahoma, Louisiana and Arkansas, as rivers reached flood stage because of the persistent rain. Later in the weekend, the region with flood watches and warnings expanded eastward and northward into the Mississippi and Ohio Valleys as the precipitation region expanded and shifted eastward. Among the daily record rainfall totals that were reported on Friday included Lufkin, TX (3.61 inches), Shreveport, LA (3.49 inches) and El Dorado, AR (2.55 inches) Unfortunately for residents of some of these areas, record rainfall totals had fallen the previous day, with Shreveport receiving 4.34 inches and El Dorado 2.10 inches on Thursday. These two days of rain also helped establish new monthly rainfall records for the month of January at Shreveport, with 12.54 inches at Shreveport as of Saturday. Amarillo, TX also had 2.58 inches for a monthly record.
Some of the thunderstorms imbedded in this precipitation shield turned severe as large hail were reported on Friday and Saturday across sections of southern and eastern Texas and western Louisiana eastward into Mississippi and northward into Arkansas. The thunderstorms also spawned several tornadoes. A tornado (rated a possible F-2 on the 5 level Fujita Tornado Intensity Scale) caused damage along a 5 mile path on Friday afternoon about 30 miles north of Beaumont in east Texas. At least one other tornado that produced some minor damage was reported in Louisiana, between Lake Charles and Alexandria.
Elsewhere, weather conditions were relatively quiet as high pressure was reported across the Middle Atlantic states and the Great Basin. On Friday afternoon Charleston (Downtown), SC reached a record high temperature of 78 degrees, Marquette, MI on the shores of Lake Superior had a record setting 36 degrees, while The Dalles, OR had a record tying 64 degrees. On Saturday, both Wausau, WI and International Falls, MN reached 43 degrees, a daily record high temperature for each station. On Sunday afternoon, International Falls reached 45 degrees -- a record high for the date.
WEATHER FOR THE START OF THE NEW WEEK -- The slow moving storm system moving across the Southeast remained a problem for many areas of the Southeast and mid Mississippi Valley on Sunday night, and undoubtedly, well into Monday. One low pressure system was located over the Bootheel of Missouri, with weak trough of low pressure extending southward across Arkansas. This system was dissipating, while a second low pressure system remained along a frontal boundary farther south over Alabama. A warm front extended eastward into toward the Atlantic Ocean, while a cold front trailed to the south over the Florida Panhandle and into the Gulf of Mexico. A large precipitation shield extended from the Northern Gulf States into the Ohio and mid Mississippi Valleys, eastward to the Appalachians in the Virginias.
One of the major weather problems that developed on Sunday was the snow and freezing precipitation that spread across the Piedmont from northeast Georgia to North Carolina. As part of the counterclockwise circulation around the low pressure system, a flow of warm and humid air from the Gulf and Atlantic was northward around the east flank of the storm system. These southerly winds were being lifted over cold air moving southward near the earth's surface. The cold air was spilling southward from a cold, elongated high pressure system that was centered over the Delmarva Peninsula. The northeasterly winds, or winds from the northeast, spiraling clockwise around the high pressure cell was bring the cold air well to the south. In many higher elevation locations, especially near Asheville, NC, rain falling from the warm tropical air aloft was freezing upon contact with the cold, sub-freezing surfaces at ground level. Freezing rain, ice pellets (sleet) and snow should continue through Monday morning as the storm system continues its slow trek northeastward. Winter storm watches were posted for portions of the Piedmont and the eastern Appalachian valleys for Sunday night and Monday. The strong onshore winds along the Southeast Atlantic coast also necessitated coastal flood warnings from South Santee River, SC to Flagler Beach, FL and high surf advisories from Surf City, NC to Sebastian Inlet, FL.
Another problem region was located across portions of the Midwest into the Mississippi and Missouri Valleys, to the north and northwest of the weakening northern low pressure center. Some regions were experiencing freezing rain as rain spread northward into a cold environment across the north. Dense fog was beginning to form over Iowa as air cooled to saturation.
A weak low had moved eastward across the Great Basin. By Sunday night this low was located near Salt Lake City, UT. Snow accompanying this system had spread across Utah, Nevada and southern Idaho. To the west of this system, cold air invaded the West Coast. Cold air at several thousand feet above the surface was producing an unstable atmospheric environment, capable of supporting vigorous vertical motions of air. Examples of this unstable environment include Seattle, WA where an afternoon thunderstorm with small hail was followed by rain, mixed with snow. In California, a funnel cloud, which did not touch the ground, was reported in the San Joaquin Valley. Rain also fell across southern California.
The strong onshore winds from the west with speeds that could range between 39 and 54 mph meant gale warnings were posted along the Coast from Cape Flattery, WA to Point St. George, CA for Monday. The onshore flow of moisture confronting the mountain barriers along the coast and inland could produce significant precipitation. Winter storm warnings were in effect for the Olympic Mountains and Washington Cascades through Monday night, where as much as a foot of new snow could fall.
TEMPERATURE EXTREMES IN THE COTERMINOUS U.S. -- The lowest temperature on Sunday was 27 degrees (Fahrenheit ) below zero at Saranac Lake, NY, while Sunday's highest temperature was 82 degrees at Punta Gorda, FL.
ALASKAN WEATHER -- Arctic air continued to keep much of Alaska in unseasonably cold conditions over the weekend as a large high pressure system with origins from over the Arctic and eastern Siberia extended across all but the southeastern corner of the state. Alaskans experienced their first 70 below day of the season on Thursday as the minimum temperature at Chandalar Lake in the Brooks Range was 71 degrees below zero. Transmission of information was delayed because the usual telecommunications malfunctioned and observations had to be relayed. In addition to air temperatures that reached to well below zero degrees Fahrenheit, strong winds were also a problem. Wind-chill equivalent temperatures in the Brooks Range fell to 100 degrees below zero or lower on Saturday. This arctic air mass was dry, with little precipitation across much of the station away from coastal areas.
As of Sunday afternoon, a large region of high pressure extended from the Russian Far East across the Bering Strait into western Alaska. A cold wave was expected to continue across northern and western interior portions of the state. One low pressure system was located in the northern Gulf of Alaska near Prince William Sound. Clouds and light snow associated with this system stretched along coastal regions from Kodiak Island to the southern Panhandle and northward into the Susitna and Tanana Valleys. As of early Sunday morning, Yakutat had received at least 15 inches of snow in 14 hours in heavy snow showers. Gusty winds were causing drifting of the snow. Another storm system to the south of Cold Bay was responsible for clouds across the Aleutians.
A strong pressure gradient between the high pressure system over northwestern Alaska and the low pressure systems over the Gulf and to the south of the Aleutians produced strong winds across many areas of southern and southwestern Alaska. A high wind warning remained in effect for Prince William Sound. The strong winds also produced dangerous wind-chill equivalent temperatures, necessitating wind-chill warnings for the Kuskokwim Delta, Bristol Bay and the Alaska Range. On Sunday, Cantwell had a wind-chill equivalent temperature of 107 degrees below zero. Warnings for dangerous wind-chills were also continued for Kotzebue Sound and the passes through the Brooks Range.
On Saturday night the temperature in Kodiak fell to 5 degrees below zero, establishing a new record low temperature for the date.
Sunday morning's lowest temperature in Alaska was 67 degrees below zero at Huslia and the state's highest temperature by mid-afternoon was 36 degrees at Hydaburg.
HAWAIIAN WEATHER -- A high pressure system that originated over the north Pacific near the Aleutians moved southeastward, passing to the northeast of the Hawaiian Islands over the weekend. As a result, strong northeast trade winds, a relatively persistent set of winds from the northeast direction that is common to the tropics, were reported across Hawaii at the start of the weekend. However, as the high pressure continued to move away from the islands, the trade winds turned to a direction that was from the east. As a result of this change in wind direction, the humidity levels of the air moving over the islands increased, along with an increase in clouds.
Wintry weather was experienced at the summits of the volcanic peaks of the Big Island. A cold pool of air that extended from near summit level to an altitude of approximately 30,000 feet produced heavy snow above 12,000 feet on the Big Island summits on Sunday morning. Winter weather advisories were posted for these peaks.
Heavy showers are expected to continue over the windward slopes of the islands through Tuesday as a result of the humid air coupled with the unstable atmospheric conditions that are conducive to the development of showers and some isolated thunderstorms, especially over the mountains of Maui and the Big Island on Sunday night and Monday.
Because of the rain, flash flood warnings were in effect for windward side of Maui, with flash flood watches for Molokai and the Big Island. Small craft advisories were posted for state waters and a high surf advisory for the north facing shores of the islands.
WHAT WILL THE GROUNDHOG SEE? -- Will cloudy conditions this morning prevent the groundhog from casting a shadow at early morning celebrations in several locates, including Wisconsin and Pennsylvania? For more details on the significance of Groundhog Day, please refer to Monday's optional Supplemental Summary Information file.
Regardless of the outcome, welcome to February! According to various sources, the name for the shortest month of the year was derived from "Februalia", an ancient Roman festival of purification at this time of year (before the new year that commenced with the spring equinox in March), during which sacrifices were made to atone for sins.
This February is special because the month will not contain a full moon, the first time since 1961 (and the next time will occur in 2018).
AN INVITE -- If you witness some interesting weather phenomena or would like to share some weather-related experience with others in the Online Weather Studies Project, we cordially invite your contributions. Please email these to the address appearing below. Some of these may appear in the section titled "Reports from the Field"
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.