Today is President's Day, a Federal holiday serving to commemorate the February birthdays of Presidents George Washington and Abraham Lincoln.
WEATHER OVER THE WEEKEND -- The beginning of the weekend saw a rather potent storm system move eastward across the Great Lakes. A rather vigorous cold front trailing the storm system was accompanied by severe thunderstorms. These thunderstorms were fueled by warm, humid Gulf air that was transported as far north as the Great Lakes on strong southerly winds. In addition, the southerly wind flow was responsible for more than four dozen high temperature records that were broken on Thursday across the Great Lakes and Ohio Valley. As the cold front pushed steadily to the east, the core of the warmest air shifted to the east, resulting in the majority of the numerous record high temperatures on Friday to be found across the eastern Lakes and the Eastern Seaboard, stretching from New England through the Middle Atlantic to the Southeastern states. With frontal passage, some locations experienced dramatic temperature falls of at least 30 degrees in less than 24 hours, as southerly winds turned to a northwesterly direction. Cleveland, OH reported a record high temperature of 68 degrees early Friday morning with southerly winds prior to passage of the cold front, but by midday, the temperature had fallen to the upper 20s as a northwest wind off of Lake Erie brought lake-enhanced snow.
By Friday evening the cold front had reached the Eastern Seaboard. Severe thunderstorms along the cold front produced winds to 60 mph and large hail across portions of North Carolina, Virginia and Maryland. Wind damage was reported in Delaware, New Jersey and southeastern Pennsylvania. A secondary cold front pin-wheeling in a counterclockwise direction around the low pressure system in northern Quebec passed across the western Great Lakes, reinforcing the invasion of cold air and producing additional lake-enhanced snow squalls. As much as 4 inches of snow fell in 12 hours as of Saturday morning across the northern portion of Michigan's Lower Peninsula, the result of lake-effect and lake-enhanced snow. Snow was also reported across the mountains of North Carolina early Saturday morning.
Cool high pressure expanded east-southeastward across the central portion of the country. While Saturday afternoon temperatures across the Northeast were noticeably lower than Friday's records, they were close to the average high temperatures typical of mid February. By Sunday morning the high pressure ridge was located over the Tennessee Valley, producing relatively cloud-free skies over much of the eastern half of the country. One notable exception was New England, where northerly winds were accompanied by light snow from off the Gulf of Maine.
The clockwise circulation around the high pressure ridge in the Southeast also produced a contrast in temperatures on Sunday afternoon. To the west of the center of the high, strong southwesterly winds caused high temperatures across the Plains and the Mississippi Valley to reach as much as 20 degrees above the corresponding average high temperatures for the date. Record high temperatures were either tied or broken in Colorado, Kansas, Nebraska and South Dakota to as far north as International Falls, MN, oft-regarded as the "Nation's Icebox", where a record high of 43 degrees was reported. Interestingly, Valentine, NE had a record high of 71 degrees on Valentine's Day. However, to the east of the ridge axis where winds were from the northwest, high temperatures along the Eastern Seaboard were nearly 10 degrees below the average highs.
In the Pacific Northwest, strong winds on Friday across Washington State preceded a new storm system that moved onshore on Saturday. Scattered precipitation in the form of rain and high elevation snow accompanied the front as it passed across Washington, Oregon and northern California. Gusty winds, reaching speeds of 63 mph were reported over the Sierras of California and Nevada. By Sunday morning this storm system had pushed eastward across the northern Rockies. Little precipitation accompanied this low pressure system.
On Friday and Saturday mornings, clear skies coupled by a weak offshore wind flow across southern California permitted temperatures to fall to record lows at both San Luis Obispo and at Santa Barbara.
WEATHER FOR STARTING THE NEW WEEK -- As of late Sunday night, much of the nation was experiencing relatively tranquil weather, as little precipitation was detected. An elongated ridge of high pressure remained entrenched over the East, with one center stretching from Georgia to Virginia and another center located over Upstate New York. As a result of the cool and dry air mass, the relatively clear skies and the weak winds near the center of the high pressure, night-time radiational cooling was enhanced. Consequently, freeze and hard warnings were posted across northern Florida, from the Atlantic coast to the Panhandle since temperatures were expected to reach the mid to upper 20s for several hours. The Southern high pressure cell is forecast to move eastward on Monday. Warmer air should return to the Southeast as the region of southwesterly winds shifts eastward.
A storm system with little accompanying precipitation was moving across the Rockies on Sunday night. One low pressure center was located in western South Dakota with a trailing cold front that was extended southwest to another low pressure cell over southern Nevada. Snow was reported over the northern Rockies, to include the Bitterroots along the Montana and Idaho border and the Absarokas of northwestern Wyoming, where several inches of additional snow were expected. This storm system was expected to move eastward across the Dakotas on Monday. Some additional moisture was forecast to be drawn into the system, resulting in the expansion of the snow across the Plains of eastern Montana and eastern Wyoming.
Along the West Coast the next storm system was several hundred miles off the coast. By Monday evening the storm should have reached the coast. With winds forecast to reach speeds between 39 and 54 mph, gale warnings were in effect for the Washington coast.
TEMPERATURE EXTREMES IN THE COTERMINOUS U.S. -- The lowest temperature on Sunday was 11 degrees at Watertown, NY while Sunday's high temperature was 83 degrees at Coolidge, AZ.
ALASKAN WEATHER -- The famous "Cold Snap of 1999" that kept an icy grip on much of Alaska for more than two weeks finally appeared to be broken over the weekend as the arctic high pressure system finally weakened and moved to the east. By Saturday morning, no reporting stations had temperatures lower than 49 degrees below zero. However, the minimum temperature at Fairbanks fell to 36 degrees below zero, marking a record nineteenth consecutive day with a minimum temperature that was lower than 35 degrees below zero. The warming trend was also accelerated by a large storm system that moved into the Bering Sea. This system was responsible for the widespread clouds that dominated a large portion of the southern half of the state on late Sunday afternoon. The low pressure center was situated to the southwest of the Pribilofs, with an occluded front curving over the Yukon-Kuskokwim Delta, Bristol Bay, eastern portions of the Alaska Peninsula and Kodiak Island. Snow fell at Cold Bay, Saint Paul, Iliamna, Homer, Seward, Whittier and Yakutat, while rain was reported at Kodiak. High winds were also associated with this system as a strong pressure gradient formed across the western portion of the state and the Bering Sea. Gambel reported gusts to 61 mph, Cape Romanzof had gusts to 58 mph and 53 mph gusts were reported at Shishmaref, while other stations on the Seward Peninsula, in the Aleutians and the Pribilofs had gusts to near 50 mph. To the north, a weak ridge of high pressure was responsible for relatively cloud-free skies across the northern interior, to include the Upper Yukon Valley.
The overnight lowest temperature in the state on Sunday morning was 40 degrees below zero at the Fort Yukon Airport and the mid-afternoon state high was 43 degrees at Hydaburg.
HAWAIIAN WEATHER --A shear line, representing the remnants of a midlatitude cold front passed across the islands at the beginning of the weekend, bringing clouds and showers. On Friday Hilo had a maximum temperature of 69 degrees and a reading of 70 degrees on Saturday, setting record low high temperatures for the two days. By Sunday, a large high pressure system shifted to the east-northeast of Hawaii turning the trade winds from the northeast to a more easterly direction across the islands. Relatively cloud-free skies were also found on the leeward sides of the islands, while scattered trade wind showers dotted the windward slopes, especially on the Big Island, where more extensive clouds and heavier showers were found. As a result of the clear skies, days are expected to be sunny and nights chilly. The trade winds are expected to diminish as the ridge of high pressure weakens. Over the first half of the weekend high ocean swell generated earlier by a storm in the Gulf of Alaska affected the north and northeast shores of the islands with surf that reached to as high as 15 feet. By Sunday morning the surf diminished, permitting the cancellation of the high surf advisories. Small craft advisories were also discontinued for all state waters.
AN INVITATION -- If you would like more background information concerning how various temperature records are identified, please consult Monday's optional Supplemental Summary Information .
TIDBITS -- At the end of last week, the National Severe Storms Laboratory in Norman, OK reported that 163 tornadoes were reported across the United States during January, representing a record number of January tornadoes. This record was more than three times the previous record set in 1975. Most of the tornadoes occurred in nine states, concentrated along the Gulf Coast and the lower Mississippi Valley, with 141 reported in Arkansas, Louisiana and Tennessee. A single day January record was set on 21 January, with 87 separate tornadoes. Eighteen deaths were attributed to the tornadoes nationally.
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.