Friday Daily Summary

ONLINE DAILY WEATHER SUMMARY

Friday, 12 February 1999

A REMINDER
POWERFUL STORM RUMBLES ACROSS THE MIDWEST
A DAY OF UPS AND DOWNS
QUIET BUT COOL IN THE WEST
YESTERDAY'S TEMPERATURE EXTREMES IN THE LOWER 48
ALASKAN WEATHER
HAWAIIAN WEATHER
HISTORICAL WEATHER EVENTS

A REMINDER -- Sunday is St. Valentine's Day! Do something nice for someone special.

POWERFUL STORM RUMBLES ACROSS THE MIDWEST -- A powerful storm system, accompanied by a potpourri of precipitation types and severe weather, continued to its trek across the Midwest on Thursday. By late that night, the storm system had a low pressure center that was located over the eastern portion of Michigan's Upper Peninsula. An exceptionally vigorous counterclockwise circulation regime encircled this storm system produced by the strong pressure gradient between the low and surrounding high pressure, as evidenced by the tightly packed isobars on Thursday's surface analysis charts. The circulation regime also contributed to the development of a definitive frontal structure associated with the storm. A warm front marking the leading edge of the northward advancing warm air on the eastern flank of the system extended southeastward from the low pressure center to Tidewater Virginia. A vigorous cold front delineating the leading edge of a dramatically colder air mass ran southward from the low center to the Louisiana Gulf Coast. Strong winds behind the cold front lowered wind-chill equivalent temperatures.

A band of precipitation stretched the entire length of the cold front, extending nearly uninterrupted from Ontario in the vicinity of Georgian Bay south to the Gulf Coast. Thunderstorms were imbedded within line of precipitation. As the cold front moved eastward during the daylight hours of Thursday, some of the thunderstorms turned severe as the result of high wind and large hail reports were originating from Arkansas, Kansas, Oklahoma, Missouri, Illinois, Indiana and Wisconsin. Several injuries were sustained as semitrailers were overturned by the winds along Interstate 74 in western Illinois. The extensive line of thunderstorms was exceptional for the time of year, and northward extent. These thunderstorms were fueled by the transport of warm, humid air northward from the Gulf into the "warm sector" of the storm, usually identified as the warmest quadrant of a low pressure system between the warm front and the cold front. The eastward movement of the cold front provided the trigger for the explosive development of thunderstorms. Some thunderstorms produced some relatively heavy amounts of precipitation.

Snow fell in the colder air to the north of the low and in the cold air to the west of the advancing cold front. Approximately 2 inches of snow fell across southeastern Minnesota, northeast Iowa and western Wisconsin. Some areas had received freezing rain earlier Thursday. With the advance of the cold air with below freezing temperatures, some of the road surfaces became slippery as the moisture that was on the road because of condensation, rainfall or snow melt began to freeze. Snow advisories were in effect for the Upper Peninsula.

This storm system is expected to move northeastward, reaching James Bay in Ontario on Friday morning. The warm sector should have progressed eastward, reaching the eastern Lakes and the Middle Atlantic States, followed by the cold front that would have reached the eastern end of Lake Erie. The threat of severe weather should continue into Friday along and in advance of the cold front.

A DAY OF UPS AND DOWNS -- The storm system that moved eastward across the upper Midwest was responsible for some impressive temperature variations, with some locations experiencing as much as a 30 Fahrenheit degree drop in temperature as the cold front passed. The temperature falls were fairly rapid, with a ten degree drop in temperature in the matter of minutes not uncommon. The strong southerly winds on the east side of the storm system was responsible for the abnormally warm conditions across a large portion of the nation east of the Rockies. This region had afternoon highs that reached 30 Fahrenheit degrees above the long term average high temperatures in the mid Mississippi Valley. Numerous daily records were broken in 15 states across the Midwest, Middle Atlantic and South. Some of these records were also monthly records, to include Milwaukee, WI (68 degrees); Detroit, WI (70 degrees); Columbus, OH (74 degrees) and Indianapolis, IN (75 degrees).

Some readings were also the highest temperatures for so early in the season. Of additional note has been the number of record high temperatures that were established in the early morning hours before the sun's warming effects could be felt. The elevated temperatures were a result of the transport of warm air northward through a process called "warm air advection". Undoubtedly, more records will be broken by early Friday morning before frontal passage causes a drop in temperature.

QUIET BUT COOL IN THE WEST -- A large high pressure cell settled in over the Great Basin on Thursday, leading to some tranquil weather across much of the West. Little movement of this system is expected on Friday. However, unseasonably cold conditions continued across the West, where afternoon high temperatures were 10 to 15 degrees lower than the average highs for this type of year. On Thursday morning, Burns, OR reported a record low temperature of 11 degrees below zero.

The next Pacific storm system was approaching the Pacific Northwest on Thursday evening, with a warm front making landfall along the Oregon coast. An increase in the southwesterly winds were expected. Some precipitation was falling along the Coast Range in western Oregon and into Washington State.

Storm warnings for winds of greater than 54 mph were posted along the Washington Coast, while gale warnings were in effect for the California coast.

YESTERDAY'S TEMPERATURE EXTREMES IN THE LOWER 48 -- The lowest temperature on Thursday was 25 degrees below zero at West Yellowstone, MT, while the day's highest temperature was 88 degrees at McAllen, TX.

ALASKAN WEATHER -- The large ridge of high pressure responsible for the record setting cold weather of the last two weeks continued to move eastward on Thursday. The ridge stretched from near the mouth of the Mackenzie River in the Northwest Territories southwestward to the western end of the Alaska Peninsula. As a result, relatively cloud-free skies were found across southern and interior Alaska. With the eastward movement of the ridge, southerly winds on the western flank helped increase the cloud cover and modify the temperatures across western sections of the state as Maritime Pacific air was brought northward. The increased clouds, that stretched from the northwest corner of Alaska to the Yukon-Kuskokwim Delta, were also in response to the presence of a low pressure over the Bering Sea near St. Lawrence Island. Snow fell at Barrow and Nome, while blowing snow was reported at Kotzebue and Prudhoe Bay. Wind conditions also accompanied this low pressure system, with winds gusting to 49 mph at Kotzebue, and to 45 mph at other locations on the Seward Peninsula. As a result, blizzard warnings were in effect for the northwest, from Seward Peninsula north to Cape Lisburne. A storm system over the western Aleutians was accompanied by clouds and windy conditions. Adak reported gusts to 49 mph and Shemya had gusts of 43 mph. Another low pressure system was situated over the Gulf of Alaska and produced cloudy skies, light precipitation and winds along the southeast and north Gulf coasts. Light snow fell at Northway, Skagway and Ketchikan, while mixed rain and snow was reported at Petersburg. Winter storm warnings for heavy snow were posted Skagway and vicinity. Valdez reported a peak gust of 69 mph, Skagway had gusts to 53 mph and Seward sustained gusts of 47 mph.

Several indicators of the warming trending that have signaled the end of the 1999 "Cold Snap" included the end of the string of fifteen days when the thermometer at McGrath remained at 20 degrees below zero or lower, and the absence of daily record low temperatures on Thursday.

The state's overnight lowest temperature on Thursday was 54 degrees below zero at Arctic Village. The midday highest temperature was 45 degrees at Hydaburg.

HAWAIIAN WEATHER -- The trailing end of a diffuse cold front moved south toward Hawaii, reaching Kauai by noon on Thursday and the other islands later in the day. This front could be thought as more of a shear line, with a change in the wind direction, from easterly to northeasterly or northerly with passage of the shear line. Some clouds and light rainfall accompanied this shear line. A high pressure system was moving eastward to the north of the islands, causing a return to the northeast trade winds. Small craft advisories were reinstated. A storm-induced swell was moving in a south-southwest direction toward the islands, with an anticipated time of arrival on Saturday. High surf could cause problems on the northeast sides of the islands, especially at Hilo and along the Oahu North Shore.

HISTORICAL WEATHER EVENTS - 12 February

From the files of the Aviation Weather Center, Kansas City, MO and Intellicast

...1899...Texas and the eastern Great Plains experienced their coldest morning of modern record. The mercury dipped to 8 degrees below zero at Fort Worth, TX, and to 22 degrees below zero at Kansas City, MO. The temperature at Camp Clarke, NE plunged to 47 degrees below zero to establish a record for the state. In the eastern U.S., Washington, DC hit 15 degrees below zero, while Charleston, SC received a record 3.9 inches of snow. (David Ludlum)
...1945...An F4 tornado hit a 41 car train in Sumter County, Alabama. Thirty nine cars were derailed. The conductor and fireman were killed and many others on the train were injured. The northern part of Montgomery, Alabama was hit by a F3 tornado on this day as well with 26 people killed. (Intellicast)
...1958...Snow blanketed northern Florida, with Tallahassee reporting a record 2.8 inches. A ship in the Gulf of Mexico, 25 miles south of Fort Morgan AL, reported zero visibility in heavy snow on the afternoon of the 12th. (12th-13th) (The Weather Channel)
...1988...A classic "nor'easter" formed off the Carolina coast and intensified as it moved up the Atlantic coast bringing heavy snow to the northeastern U.S. Totals ranged up to 26.1 inches at Camden, NY, 26 inches at Chester, MA and 24 inches at Berlin, NH and Rochester, VT. Arctic cold gripped the north central U.S. Duluth, MN was the cold spot in the nation with a low of 32 degrees below zero. (The National Weather Summary) (Storm Data) (Intellicast)
...1989...Unseasonably mild weather prevailed across Alaska. Morning lows of 29 degrees at Anchorage and 31 degrees at Fairbanks were actually warmer than those in northern Florida. (The National Weather Summary)
...1990...Strong southerly winds ahead of an arctic cold front pushed temperatures into the 70s as far north as Iowa and Nebraska. Twenty-one cities in the central U.S., seven in Iowa, reported record high temperatures for the date. Lincoln, NE reported a record high of 73 degrees, and the afternoon high of 59 degrees at Minneapolis, MN smashed their previous record for the date by twelve degrees. Springfield, IL reported a record forty-eight consecutive days with above normal temperatures. (The National Weather Summary)

13 February

...1784...Ice floes blocked the Mississippi River at New Orleans, then passed into the Gulf of Mexico. The only other time this occurred was during the "Great Arctic Outbreak" of 1899. (David Ludlum)
...1885...The "Friday the 13th" avalanche at Alva, UT killed sixteen persons, and left thirteen others buried for twelve hours before being rescued. (David Ludlum)
...1899...It was the coldest morning of record along the Gulf Coast. The temperature dipped to 6.8 degrees above zero at New Orleans, LA and Pensacola, FL, and plunged to 1 degree below zero at Mobile, AL. The mercury dipped to 2 degrees below zero at Tallahassee, the coldest reading of record for the state of Florida. The record low temperature for the state of Louisiana was set at Minden, when the thermometer fell to 16 degrees below zero. A trace of snow fell at Fort Myers, FL. This was the farthest south snow has ever been observed in the U.S. until 1977. The coldest temperature ever recorded at Dayton, OH occurred when it dropped to 28 degrees below zero. On the edge of the greatest arctic outbreak of all time, a vicious blizzard pounded the mid-Atlantic and New England states. Twenty inches of snow fell at Washington, DC and 34 inches fell at Cape May, NJ. The central pressure of the storm was estimated to be 966 millibars (28.53 inches) just southeast of Nantucket, MA. (David Ludlum) (Intellicast)
...1905...Morning lows of 29 degrees below zero at Pond, AR, 40 degrees below at Lebanon, KS, and 40 below at Warsaw, MO established all-time records for those three states. (The Weather Channel)
...1958...Snow fell along coastal sections from Louisiana to Florida. Vermillion Locks, LA measured 5 inches, Burrwood, LA had 2 inches, and Tallahassee, FL recorded 3 inches. Jacksonville, FL recorded 1.5 inches which was the first measurable snowfall in 59 years. (Intellicast)
...1989...Showers and thunderstorms produced locally heavy rain and flash flooding from central Texas to western Pennsylvania. Up to ten inches of rain deluged western Kentucky in two days, with five day totals ranging up to 13.16 inches at Gilbertsville Dam, KY. Flooding caused tens of millions of dollars damage, including 18 million dollars damage at Frankfort, KY. (The National Weather Summary) (Storm Data)

14 February

...1899...A great blizzard struck the eastern U.S. Washington, DC received 20.5 inches of snow to bring their total snow depth to nearly three feet. The storm produced 36 inches of snow at Cape May, NJ. (David Ludlum)
...1940...A "Saint Valentine's Day Blizzard" hit the northeastern U.S. Up to a foot and a half of snow blanketed southern New England, and whole gales accompanied the heavy snow stranding many in downtown Boston. (David Ludlum)
...1988...Strong northerly winds ushered arctic air into the north central U.S. Snow and high winds created blizzard conditions in Minnesota and the Dakotas. Winds gusted to 56 mph at Rapid City, SD, and reached 65 mph at Cody, WY. (The National Weather Summary) (Storm Data)
...1990...Valentine's Day was a snowy one for many parts of the western and central U.S. Five to ten inches of snow fell across Iowa, and 6 to 12 inches of snow blanketed northern Illinois, and strong northeasterly winds accompanied the heavy snow. Air traffic came to a halt during the evening at O'Hare Airport in Chicago, where 9.7 inches of snow was reported. More than 250 traffic accidents were reported around Des Moines, IA during the evening rush hour. An icestorm glazed east central sections of Illinois, causing twelve million dollars damage in Champaign County alone. (The National Weather Summary) (Storm Data)