NATIONAL WEATHER SUMMARY

JANUARY 2013

 

1^st-5^th…As 2013 began, frigid conditions became established across the Intermountain West. In Alamosa, CO, lows dipped to -30°F or below on 5 consecutive days (January 2-6) for the first time on record. Previously,

Alamosa’s longest such streak had been 4 days—from January 18-21, 1984. Alamosa also posted daily record lows on January 3-4 (-33 and -34F, respectively). Other Western daily-record lows included -22F (on January 4) in Randolph, UT; -16F (on January 3) in Winnemucca, NV; -15F (on January 3) in Pocatello, ID; and -13F (on January 2) in Burns, OR. Meanwhile, high temperatures above 80F were confined to southern sections of Texas and Florida. On December 30, however, the nation’s highest temperature was just 73F in Harlingen, TX. Suddenly mild weather in Alaska boosted weekly temperatures more than 20F above normal at some

interior and western locations. Following 9 consecutive days (December 15-23) with lows of -40F or below, Fairbanks warmed to 34F on December 31

and January 1. On the same dates, McGrath posted consecutive daily-record highs (45 and 47F, respectively). Meanwhile, parts of southern Alaska received significant precipitation. Juneau’s weekly precipitation total of 1.57 inches (2.9 inches of snow) was aided by a daily-record rainfall of 0.81 inch on December 30. Weekly precipitation reached 3.30 inches on Annette Island and 3.09 inches in Yakutat. Farther south, wetter and increasingly windy conditions prevailed in Hawaii. On Oahu, Honolulu followed its driest December on record (0.01 inch, or 3.23 inches below normal), with rainfall totaling 0.14 inch from January 1-5. Kahului, Maui, also received more rain from January 1-5 (0.81 inch) than during all of December (0.24 inch, or 3.11 inches below normal). Twenty-four hour rainfall totals topped 4 inches in a few spots, including Kilohana, Kauai, where 4.62 inches fell on December 31 – January 1. At week’s and, trade wind gusts to 44 mph were clocked on January 5 at the Molokai Airport, along with Honolulu and Kahului.

 

6^th-12…Severe weather developed over the lower Mississippi River Valley on Thursday, while heavy snow showers moved through the Intermountain West, Northern Rockies, and Great Basin. A low pressure system over the Southern Plains advanced northeastward and created a strong frontal boundary over the Lower Mississippi River. A warm front stretched eastward over the Southeast, while a cold front followed closely behind and moved eastward from eastern Texas. Abundant moisture poured in from the Gulf of Mexico, which supplied energy into this system and allowed for severe thunderstorms to develop over Louisiana and Mississippi. The region saw heavy rainfall and strong winds, with even some tornado development. Mid-day rainfall totals surpassed 2 inches in many areas, with the heaviest rainfall reported in Alexandria Esle, Louisiana with a mid-day total of 4.02 inches. Strong winds blew down multiple trees and power lines across Mississippi. A tornado touch down was spotted at an industrial plant near Plaquemine, Louisiana. Near the center of the low pressure system, precipitation continued as it moved northward from the Southern Plains and into the Mid-Mississippi Valley. Widespread rain showers stretched from Kansas, into Indiana, with areas of snow showers in Nebraska and Iowa. Meanwhile in the West, a broad low pressure system moved over the Western States and created heavy snowfall across Idaho, Montana, Nevada, and Utah. Snowfall accumulation for Idaho has ranged from 3 to 8 inches and western Montana reported mid-day snowfall accumulation from 5 to 10 inches. Heavier snowfall fell at highest mountain peaks and passes. High wind advisories were issued along the leading edge of this system as winds gusted from 40 to 60 mph. Strongest winds were reported at Ogden Peak which is in the Wasatch Mountains of Utah at 9,570 feet with 95 mph gust.

A system produced flooding problems in Louisiana and Mississippi the past several days finally left the area Friday and headed to the north. Moderate to occasionally heavy rain moved through the Mississippi Valley and into the Ohio Valley, leaving mostly dry conditions for most of the Southeast. In addition to the rain in the Ohio Valley, a mixture of rain and snow also moved through the Great Lakes. There was not a tremendous amount of cold air to support the snowfall, so the snow gradually became rain as the day progressed. Meanwhile, a strong storm continued to bring Arctic air southward into the West and Rockies. This cold air aided in the production of well over a foot of new snow in the higher elevations of the Great Basin and Rockies. More snow is anticipated through Saturday as Winter Storm Warnings and Winter Weather Advisories remain posted. The secondary effect of this storm is the widespread cold air that not only occurred Friday morning, but was expected to continue through the weekend. While temperatures plummeted below zero for many locations in the Rockies, even colder temperatures between -20 and -30 will be likely through the weekend. Due to the sub-freezing temperatures in the Central Valley of California, farmers have gone to great lengths to protect their crops. More cold nights are anticipated through the weekend. The Northeast rose into the 30s and 40s, while the Southeast saw temperatures in the 60s and 70s. The Northern Plains saw a variety of temperatures from the 10s to the 40s, while the Rockies rose into the 10s, 20s, and 30s. The Northwest rose into the 20s and 30s.

13^th-19^th…Heavy rain and snow moved through the Southeast on Monday as a strong cold front continued to move eastward through the Eastern U.S. The northern side of this front pulled eastward and offshore of the East Coast, while the southern side of this front stretched from the Lower Mississippi River Valley to the Carolinas and Virginias. Abundant moisture and energy fed into this system from the Gulf of Mexico, which allowed for heavy rains and flooding to remain of concern for the Lower Mississippi River Valley and the Tennessee Valley. Cooler temperatures along the back side of this system allowed for rain showers to turn to freezing rain and snow showers across northern Mississippi and the Tennessee Valley. Scattered snow showers moved from Arkansas and southeastern Missouri, into Illinois and Indiana. Ice storm warnings and freezing rain warnings were issued for Lower Mississippi and Tennessee Valleys. Daytime highs in these areas remained well below seasonable with highs in the upper 20s to mid-30s. Heaviest rainfall ahead of the cold front was reported in Andrews, North Carolina with a mid-day total of 1.86 inches of rain. Meanwhile out West, cold conditions continued for the West Coast, Desert Southwest, and Rocky Mountains. Freeze and frost warnings remained in effect for the interior valleys of California and most of Arizona, as daytime highs remained in the 40s, and overnight lows dropped into the mid-20s. Just to the east, a trough of low pressure over the Southern Rockies allowed for scattered snow showers to develop over northern New Mexico. Snowfall accumulation ranged from 2 to 5 inches in most areas.

Snow and freezing rain moved into New England on Wednesday, while heavy rain showers continued across the Southeast. A frontal boundary lingered over the Southeast and triggered more heavy rains from the Lower Mississippi River Valley through the Mid-Atlantic states. As this system advanced northeastward, cooler temperatures in the north allowed for rain showers to turn to freezing rain and snow showers from the Central Appalachians through Maine. Snowfall accumulation ranged from 3 to 6 inches by mid-day on Wednesday, while rainfall totals varied around an inch. Coatesville, Pennsylvania reported 1.04 inches of rain, while Greenville, New York reported 5.5 inches of new snow. Temperatures southeast of the frontal boundary remained in the upper 70s to lower 80s, while temperatures behind the front ranged in the mid-30s. Behind this system, a strong arctic cold front dropped southward from western Canada and created scattered snow showers across the Dakotas and Upper Midwest. Snowfall accumulation has varied around 1 to 2 inches, but cooler temperatures associated with this front allowed for highs to range in the teens and overnight lows dipped into the negative teens across the Northern Rockies. Out West, high pressure maintained chilly but dry conditions with plenty of sunshine for most of the West Coast and Desert Southwest.

The eastern half of the nation saw another chilly day on Friday. Precipitation ended for the Southeast on Friday as a frontal boundary finally pushed offshore and into the Atlantic Ocean. This allowed for high pressure to build in and dry conditions to return. However, chilly conditions persisted as flow from the north bought cooler air into the region. Highs ranged in the upper 20s in the Northeast, to the upper 30s to lower 40s in the Mid-Atlantic states. Flooding remained a concern for the Lower Mississippi River Valley as the region starts to dry out from the heavy rainfall that affected the Southeast for over a week. Meanwhile to the north, a trough of low pressure dipped into the Northern states from central Canada and pushed a warm front over the Upper Midwest. This system kicked up periods of moderate to heavy snow showers as it moved eastward and over the Great Lakes throughout the day. Snowfall accumulation ranged from 3 to 5 inches from northern and central Minnesota, across most of Wisconsin, and into Michigan. While this warm front triggered snow showers, it brought warmer air in from the south, allowing for high temperatures to return to the lower 20s for the region.

Out West, a warming trend persisted for the West Coast as high pressure strengthened and flow from the north weakened. This allowed for sunny skies and highs to return to the lower 60s to mid-70s.

 

20^th-26^th…Cold temperatures gripped the northeastern quadrant of the nation on Monday as a cold arctic air mass prevailed across the region. Daytime highs ranged from below zero in parts of the Dakotas and upper Mississippi Valley to the single digits in the Upper Great Lakes and interior Northeast to the 30s across parts of the Lower Ohio Valley and New England areas as cold northwesterly flow whipped across the region. Bitterly cold temperatures combined with northwest winds of 10 to 15 mph and higher gusts created dangerously cold wind chills of 25 to 45 below zero during the morning and nighttime hours across parts of the Dakotas through Wisconsin and in parts of the upper Northeast. Meanwhile, low pressure cut across the Great Lakes this afternoon and headed toward the Northeast with lake effect snow showers. Elsewhere, outside of a few light showers in the Florida Peninsula, a quiet weather day developed across the rest of the nation as high pressure remained dominant in the West.

Wet and snowy conditions spread across the eastern valleys and Great Lakes, while rain showers persisted in the Southwest and Northwest on Friday. A low pressure system over the Southeast advanced northeastward over the eastern valleys and cold temperatures over the region allowed for scattered snow showers develop across the Mid-Atlantic states and Northeast. At the same time, another low pressure system moved into the Great Lakes from the Northern Plains. Warmer temperatures along the southern side of this system allowed for freezing rain and rain showers to spread across the Tennessee Valley and into the Carolinas. Snowfall totals ranged from 3 to 5 inches from Wisconsin through Pennsylvania, with 1 to 2 inches across the Virginias. Ice accumulation over the Tennessee Valley reached over a quarter of an inch, which created dangerous roads and travel conditions. Meanwhile, out West, two weather systems created active weather for the West Coast. In the south, a low pressure system off the coast of southern California advanced eastward and pushed abundant moisture onshore. This kicked up scattered showers across the Desert Southwest. To the north, a low pressure system and associated cold front moved in from the Gulf of Alaska, which created scattered rain showers with high elevation snow showers as it moved over the Pacific Northwest and into northern California.

 

27^th-31^st…The strong winter storm that brought a wintry unsettled weather to the Midwest ushered the a wintry mix of precipitation into New England and the Upper Mid-Atlantic on Monday as the low lifted across the Great Lakes and the associated warm front reached eastward. A mix of light freezing rain, sleet, and snow developed in parts of southern and western New York, New Jersey, and Pennsylvania through the morning and began to change into rain through the afternoon as temperatures rose above the freezing mark. The rest of the region continued to see freezing rain and sleet through the day. These conditions led to ice covered roads and sidewalks, as well as possible issues with power outages and downed tree limbs in areas that experience the greatest ice accumulations. In addition to ice, snow showers continued across the Northeast, south of Maine, with snow accumulations expected to range from 2 to 5 inches by Tuesday morning. Outside of this area of precipitation, rain and snow in the Upper Great Lakes moved into southeastern Canada, while light to moderate rain showers developed from portions of the Southern Plains into the Midwest. Out West, a wave of low pressure over the Rockies spread snow showers from the Northern Rockies across the Northern Plains and into the Upper Mississippi Valley during the afternoon. The southern portion of this disturbance remained stretched across the Intermountain West and maintained a mix of rain and high elevation snow in the Four Corners and Wyoming. Snowfall accumulations were expected to reach up to a foot in the mountains. Further West, a moist storm system brought another round of rain and snow to the Pacific Northwest with up to a foot of snow expected across the Cascades.

Jim G. Munley, jr.
http://www.jimmunleywx.com