WEATHER OVER THE WEEKEND -- Weather systems were slow to move this weekend as a result of a looping circulation regime in the mid to upper troposphere that tends to stagnate. The Southeast as well portions of the southern Rockies and the Southwest were cloudy, wet and unseasonably cool, while in between, the Midwest and southern Plains had pleasant weather.
A storm system in the Southeast brought cool, cloudy, rainy and windy weather to the Southeast. This storm system was located off the South Carolina coast for much of the weekend. Starting at midweek, more than 8 inches of rain fell across portions of North Carolina. Many locations across the Southeast had record low maximum temperatures. On Friday afternoon Raleigh-Durham, NC reached a high temperature of only 58 degrees, a record low high for the date. Other record low highs included Atlanta, GA (55 degrees), Charleston/Airport (55 degrees), Jacksonville, FL (56 degrees) and Tallahassee, FL (60 degrees). Beech Mountain, NC reported 6 inches of snow by Friday morning. Record low temperatures were either tied or set on Saturday morning at Mobile, AL (46 degrees) and in Florida, at Orlando (53 degrees), West Palm Beach (54 degrees), Fort Lauderdale (57 degrees), Miami (58 degrees) and Miami Beach (61 degrees). Record low high temperatures were set on Saturday at West Palm Beach (54 degrees), Miami (58 degrees), Miami Beach (61 degrees), Jacksonville (61 degrees), Daytona Beach (66 degrees), Tampa (68 degrees), Orlando (68 degrees) and Melbourne (71 degrees). Record low temperatures were either tied or set on Sunday morning at Mobile, AL (50 degrees) and across Florida at Lakeland (42 degrees), Tampa (52 degrees), Orlando (54 degrees), Melbourne (54 degrees), Palm Beach (55 degrees), St. Petersburg.(56 degrees), Hollywood (57 degrees), Fort Lauderdale (58 degrees), Miami (60 degrees) and Miami Beach (61 degrees).
A complex storm system that was in the Southwest moved into the Rockies. Heavy rains were found at several sites along the eastern slopes where heavy rain was partially the result of upslope conditions. More than 10 inches of rain were recorded at several locations near Colorado Springs, CO starting on Wednesday of last week. Daily records were set at Colorado Springs, where 2.63 inches fell on Friday, with 0.82 inches on Saturday. Likewise, at Pueblo, a record 2.00 inches fell on Friday and 1.02 inches for Saturday. On Friday, Cheyenne, WY received 1.62 inches of rain, a daily 24 hour precipitation record for the date, and the second wettest day ever recorded in Cheyenne during the month of April. On Saturday U.S. Highway 550 across Red Mountain Pass north of Durango, CO was closed because of an avalanche. Las Vegas, NV had a high temperature of 56 degrees on Friday, setting a low maximum temperature record.
To the east of the storm, thunderstorms developed and moved across the southern Plains. On Saturday evening, 5 reports of tornadoes were made from the Texas Panhandle, together with reports of large hail. By Sunday, thunderstorms developed across east Texas, accompanied by large hail.
A large sprawling high pressure system moved southeastward from Canada to a position over the Great Lakes at the beginning of the weekend. Much of the region experienced pleasant weather, with relatively cloud-free skies and low humidity. However, the low humidities also contributed to large diurnal ranges in temperature. On Friday morning, the minimum temperature of 39 degrees at Jackson, KY established a new record low temperature. On Sunday, the afternoon high temperature at Marquette, MI was 78 degrees, a record high for the date.
WEATHER FOR STARTING THE NEW WEEK -- The storm system that has affected the Southeast over the weekend continued to move slowly northward paralleling the coast, reaching a position offshore of Cape Hatteras, NC on Sunday night. The system remained sufficiently strong with onshore northeasterly winds so as to require heavy surf advisories to remain in effect for portions of the coast from Fenwick Island, DE to Currituck Beach Light, NC. Gale warnings were also in effect for portions of the coast from Cape Charles, VA to Cape Hatteras, NC. Farther south, heavy surf advisories were also in effect for the Florida coast from Flagler Island to Angelfish Key. Most of the moderate to heavy rain that had fallen across portions of Virginia and North Carolina had ended. Rain was beginning to fall across the eastern end of New York's Long Island and portions of Cape Cod in Massachusetts. This system is expected to move northward.
Several low pressure systems were located on the lee-slopes of the Rockies. One low pressure center was situated in the Nebraska Panhandle, while the other was located in eastern Colorado. To the east of these systems, thunderstorms earlier on Sunday evening turned severe, spawning tornadoes, and producing large hail across south central Nebraska in the vicinity of Hastings and Grand Island. Some of the tornadoes did damage. Major flooding from previous rains and mountain snowmelt continued along the Arkansas River in southeastern Colorado in the vicinity of La Junta. Three-quarters of North La Junta was under water and a portion of U.S. Highway 50 was closed.
One of the low pressure systems is expected to move eastward across the Plains, accompanied by precipitation that should spread eastward to the Missouri and Upper Mississippi Valleys by Monday morning. A slight threat of severe weather is expected across the Plains, extending from eastern Nebraska southward into southern Kansas through Monday morning. This region expands southward to encompass much of north and central Texas.
Farther west, a cold front that extended southward from a low in northern Saskatchewan crossed eastern Montana, central Wyoming and Utah before curving westward to cross southern Nevada and California. Several weak low pressure centers were found along the front. Behind the front, widely scattered precipitation was found across the Intermountain West and the Pacific Northwest. Snow fell across the higher elevations of the Bitterroots of Idaho and Montana, the Cascades of Washington and the Sierras of California.
A variety of snow advisories were in effect across the mountains of Idaho, northwest Montana the Washington Cascades for snowfall accumulating to as much as 6 inches.
A large ridge of high pressure centered over Georgian Bay and Lake Huron extended southward to the Gulf Coast maintained pleasant weather across the Great Lakes States and into the Northeast as well as southward to the Southeastern states. This system is expected to move only slowly eastward as of Monday morning. Because of the dry air mass, clear sky and the weak winds, a frost warning was posted for western portions of North Carolina.
UPPER AIR -- The 500 and 300 mb charts for 00Z Monday showed a large trough of lower heights across the Western states, a height ridge in the center of the country and a weaker trough along the Eastern Seaboard.
TEMPERATURE EXTREMES IN THE COTERMINOUS U.S. -- The lowest temperature on Sunday was 24 degrees at Alamosa, CO while Sunday's highest temperature was 97 degrees at Lajitas, TX.
ALASKAN WEATHER -- A large low pressure system was centered over the northeastern Gulf of Alaska between Middleton Island and Yakutat with a weak front that extended southeastward over Southeast Alaska. Clouds and precipitation associated with this system were found across Southeast Alaska. Snow was reported in the interior, while rain was found along the coast. A small region of low pressure was located south of Shemya. A weak trough was located along the Brooks Range.
The lowest overnight temperature in the state as of Sunday was 2 degrees below zero at Kotzebue. Sunday's midafternoon highest temperature was 49 degrees at Cordova and Valdez.
Juneau received 7.48 inches of precipitation during April, setting an April precipitation record. As of the end of April, Cold Bay has received a record 149.8 inches of snow for the 1998-99 season.
HAWAIIAN WEATHER -- A high pressure ridge that extends from the eastern North Pacific across the islands is expected to maintain fair weather over Hawaii for the beginning of the week. Some isolated afternoon showers could develop over the interior portions of the islands. Surface winds should be from the southeast across the islands, except for easterly trades across Maui and the Big Island.
PRELIMINARY STATISTICS ON APRIL -- Boston (Logan), MA received only 0.83 inches of precipitation during the month of April, making the just concluded month the driest April on record that extends back to 1872. Mobile, AL had only 0.08 inches of rainfall during April, which is now the driest April on record and 4.40 inches below the 30 year climatological average for the city.
On the other hand, the 6.30 inches of precipitation recorded at Amarillo during April was the second largest amount in April, only 0.15 less than the record precipitation total. Elko, NV had a 16.6 inches of snow during April, the second highest snow total for the month of April.
A DEADLY AVALANCHE YEAR -- According to the Colorado Avalanche Information Center, as of the end of April, avalanches across the U.S. have claimed 32 lives, representing the highest loss of life due to avalanches since the winter of 1925-26 and fifth behind the 1909-10 winter when 110 people died. Many of the avalanche victims this winter were skiing, snowboarding or snowmobiling.
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.