NATIONAL WEATHER SUMMARY

NOVEMBER 2010

 

1^st-6^th…Plenty of active weather developed over the southeastern quadrant of the nation on Wednesday as a low pressure system trekked eastward along the Central Gulf Coast and an associated frontal boundary extended from the Central Gulf Coast to the Georgia Coast. Abundant moisture availability combined with these systems to produce numerous showers with periods of heavy prolonged rains from eastern Texas through parts of Georgia. Widespread rainfall amounts of 2 to 4 inches were likely while 4 to 6 inches were possible in localized areas. High rainfall totals created chances of localized flooding of poor drainage areas. Lighter precipitation also fell across Kentucky, Tennessee, and the central Mid-Atlantic region. While widespread severe thunderstorm development was not expected, many of the stronger showers or thunderstorms across the area will were likely have wind gusts from 40 to 50 mph and small hail. Meanwhile, to the north, a cold front moved through the Upper Great Lakes and kicked up light showers in areas of Minnesota, Wisconsin, and Michigan. Finally, calm weather conditions with mostly sunny skies prevailed over much of the West today. A large ridge of high pressure dominated the region and provided dry conditions with above normal temperatures from much of the West Coast to the Continental Divide.
Saturday was a transition day in regard to weather as not many areas experience precipitation. The only areas of precipitation were noted in the Appalachians, Mid-Atlantic, central California, and Washington, but all of this precipitation was scattered in nature. The storm that brought wet weather to the Northeast earlier in the week finally moved out of the area. The lasting effect of this storm was the cold air that remained over the eastern third of the country. Near freezing temperatures were noted in the Southeast Saturday morning, instigating Freeze Warnings that will also be posted Sunday morning. The middle portion of the country was dry as a high pressure system moved out of the Rockies and into the Plains. This high carried warmer temperatures with it, contrasting the cold temperatures east of the Mississippi Valley. A powerful Pacific storm was set to slam into the Northwest and California later Saturday and through Sunday, providing heavy rain and high elevation snow. The Northeast rose into the 30s, 40s, and 50s, while the Southeast saw temperatures in the 40s, 50s, and 60s. The Plains rose into the 60s and 70s, while the Northwest saw temperatures in the 40s and 50s. The Southwest rose into the 70s and 80s for the most part.

7^th-13^th…A potent storm in the Northeast brought messy weather conditions to the region on Monday. A few inches of snow fell throughout the Mid-Atlantic and New England, while cold rain was reported in the slightly warmer areas. The storm began to rapidly strengthen as it moved off the coast, bringing strong winds to the coast of New England. The strengthening storm also helped to keep rain going over the interior into the evening hours, even as it moved further from the coast. Over the nation’s mid-section, high pressure centered over the South brought clear skies and a an absence of precipitation. In addition, the southerly winds on the back side of the high brought warm weather to the Plains. Temperatures reached into the 80s as far north as Nebraska.  The intermountain West saw rain and snow on Monday as a cold front pushed through the mountains. Cold air behind the front extended into the Northwest where temperatures were below normal. California saw sunny skies Monday as high pressure re-built over the state. Temperatures were close to normal for the majority of the state.                                The main weather system in the country was a low pressure system that moved through the Plains. While there was not a tremendous amount of moisture wrapped up in this system, areas of rain and snow fell mainly in the Central and Northern Plains. This activity was expected to continue into the evening, and Winter Weather Advisories are posted in North Dakota to reflect this winter weather. In addition, scattered snow showers developed through the Great Basin and Rockies that spawned Winter Weather Advisories from eastern Nevada through the mountainous areas of western Colorado. The only other precipitation fell in New England as a long-lived storm off the Northeast Coast produced some rain along the coast of New England. This precipitation was not widespread and diminished as the storm moved offshore. A high pressure system kept dry conditions dominant in the Southeast and the Ohio Valley. The Northeast rose into the 40s and 50s, while the Southeast saw temperatures in the 60s and 70s. The Northern Plains rose into the 30s, 40s, and 50s, while the Southern Plains saw temperatures in the 70s and 80s. The Northwest rose into the 40s and 50s.

14^th-20^th…A strong frontal boundary extended down the East Coast on Monday, which brought scattered showers to the Northeast and heavy rains to the Southeast. The front was created as a low pressure system developed in the Gulf of Mexico. Flow around this area of low pressure pushed ample moisture over the Gulf states, which allowed for moderate to heavy showers and thunderstorms to develop. These storms have not yet turned severe, but rainfall totals have reached up to 1.51 inches in Atlanta, Georgia, to 2.03 inches in Alexander City, Alabama. In the North, rain showers remained light, less than a tenth of an inch, due to less available moisture. Just behind this system in the Southern Plains, scattered showers developed ahead of a trough of low pressure. Rainfall totals only ranged from 0.09 inches in Meridian, Oklahoma, to 0.14 inches in Watonga, Oklahoma. Meanwhile in the West, a trough of low pressure over the Rocky Mountains triggered moderate to heavy snowfall across the Northern and Central Rockies. Snowfall totals ranged from 6 to 11 inches across higher elevations of Colorado and 2 to 4 inches in Utah. Montana and Wyoming saw between 1 to 3 inches of snow. Further west, scattered showers returned to the Pacific Northwest as a low pressure system in the Pacific pushes a cold front onshore. Most areas saw light showers with rainfall totals less than a quarter of an inch. California and the Southwestern US remained warm and dry as a ridge of high pressure created strong offshore flow.

Several areas of active weather developed across the nation on Wednesday.

 

In the West, a deepening low pressure system located off the coast of southwestern Canada ushered a strong frontal system and gusty southeast winds toward the Pacific Northwest. A mixture of scattered rain showers and high elevation snow developed ahead of this front, across areas of western Washington and Oregon through the afternoon. The eastern slopes of the Olympics and Cascades experienced periods of heavy snowfall as snow levels dropped from a morning level of 3,000 feet. Snow levels in the north and south were expected to fall to about 1,000 to 2,000 feet by the night. Winter Weather Advisories and Winter Storm Warnings remained over portions of the Pacific Northwest. Elsewhere in the West, gloomy skies hung over the rest of the Northwest as pockets of lingering snow showers from the Northern Intermountain West through the Northern Plains began to taper off. Drier, calmer, and clearer weather conditions continued over California and the Southwest. In the East, wet and windy weather continued over the northeastern corner of the nation as a low pressure system trekked from lower Ontario into the Quebec province this afternoon. The low brought strong, gusty winds to the eastern Lower Great Lakes, the Northeast, and the Central Appalachians. Wind gusts up to 50 mph were expected mainly over the higher terrain of northeastern Pennsylvania and central New York. The aforementioned regions remained under Wind Advisories through the afternoon. In addition to wind, areas of scattered rain showers continued to affect areas from Michigan through Maine during the afternoon. In the South, a fast moving low pressure system over north-central Oklahoma spread rain showers across eastern Kansas, eastern Oklahoma, and northwestern Arkansas. Gusty winds accompanied the low and affected areas of south-central Kansas through the Texas Panhandle, as well as portions of northeastern Texas. Elsewhere, high pressure dominated much of the Southeast with dry and mild weather conditions. Drier and cooler air moved in behind a cold front over the Florida Peninsula.

The West remained snowy and rainy as a trough of low pressure and associated cold front dipped in from British Columbia on Friday. The system obtained ample moisture from the Gulf of Alaska and Pacific Ocean, which allowed for periods of heavy rain showers to develop across Oregon and Washington, while heavy snowfall developed at higher elevations of the Northern Rockies, Intermountain West, and Great Basin. Parts of Idaho reported between 1-3 inches of snow, while the high elevations of northern California reported 2-4 inches of snow. Snow across the Cascades diminished throughout the day, as the system dug further south, down the West Coast. Snow levels across the Northern Rockies dropped to valley floors, but remained at 2,500 feet across the Sierras and Intermountain West. Highest mid-day rainfall reached up to 0.71 inches at North Bend, Oregon, while most of northern California saw less than a tenth of an inch of rain. However, Alturas, California reported 0.16 inches of rain. Elsewhere, mild weather persisted across the rest of the nation. A ridge of high pressure over the Eastern US brought cool and dry air in from Canada. This brought a chilly Fall day with highs in the North ranging in the 40s, and the Southeast reached highs near 70. In the Northern Plains, a mild trough of low pressure skirted eastward along the Canadian border. This brought scattered rain and snow showers to the Northern Plains and Upper Midwest. Snowfall totals remained light with total accumulation less than a half of an inch.

 

21^st-27^th…Most of the nation saw active weather on Monday. A trough of low pressure over the Western US continued pulling cool and moist air in from the Gulf of Alaska. This system pushed a front eastward and over the Intermountain West and into the Northern Rockies. Periods of heavy snow developed in the mountains, with rain showers at lower levels. Winter weather advisories have been issued across most of the Western US, as snowfall accumulation ranged from 0-3 inches in Idaho, to 3 inches in Utah, and up to 6 inches in the Sierras and Cascades. Snow levels moved up to 5,000 feet across the Sierras, and remained at the valley floors elsewhere. Some high elevation mountain passes saw near a foot of snow on Monday. In the East, a low pressure system moved into the Great Lakes and pulled a cold front over the Mississippi River Valley. The system produced some light snow showers over the Upper Midwest and Great Lakes with accumulation between 2-4 inches in the extreme northern areas. The cold front to the south kicked up periods of heavy rain, with hail even reported in Oneida and Sheffield, Illinois. Heaviest rain was reported in Saginaw, Michigan with a mid-day total of 1.11 inches. Elsewhere along the front, rainfall totals ranged from 0.25 to 0.75 inches. These systems both allowed for cool air to pour in from the north, thus, high temperatures remained relatively low across most of the nation. The Northwest saw highs in the upper teens, while the Northern Plains and Upper Midwest saw highs in the lower teens. The Northeast and New England remained warmer in the 40s and the Southeast and Southern Plains remained seasonable with highs in the 70s.

Holiday travel across the central part of the nation some severe delays as a winter storm moved into the Midwest. A low pressure system strengthened as it moved off the Rockies and into the Northern Plains. Precipitation associated with this system intensified and winds strengthened, due to a drastic change in pressure from the Northern Rocky Mountains to the Northern Plains. Winds reached up to 53 mph in Rapid City, South Dakota. Most of North Dakota and Minnesota saw between 1 to 3 inches of snow. Heaviest rainfall developed along a warm front that lead the system over the Mississippi Valley and into the Midwest. Rainfall totals reached up to 1.69 inches in Evansville, Indiana and 1.99 inches in St. Charles, Missouri. Severe weather has not yet been reported, but flooding threatened most of Illinois and Indiana. In the South, the back side of this low pressure system also brought extremely windy conditions, as well as dry air in from the north. Thus, fire advisories have been issued across the Southern Plains with sustained winds reported at 30 mph and gusts up to 35 mph in Hart, Texas. The Southeast remained dry and warm with highs in the 70s. Higher pressure dominated over the Northeast and New England, which brought a sunny and chilly pleasant day with highs in the 40s. The West Coast finally saw some dry conditions as the low pressure system moved eastward and away from the region. Strong flow from the north pushed cool and dry air across California. Overnight lows dipped below freezing over much of northern California, while daytime highs ranged in the 40s. The Pacific Northwest saw some lingering clouds and cold temperatures with highs in the lower 30s.

The weather on Thanksgiving Day brought dangerous travel conditions to most of the Eastern US. A strong winter storm continued to track eastward across the Central US and into the Great Lakes. Counter-clockwise flow around this system pushed cool and dry air in from central Canada, which allowed for extremely cold temperatures across the Northern Plains and Upper Midwest. Highs only reached into the teens across the region. This strong surge of cold air also created a cold front that moved over the Midwest, up the Ohio River Valley, and stretched down the Mississippi River. Temperatures remained above freezing along most areas of this cold front, thus, precipitation remained as rain showers. Some areas saw scattered thunderstorms, with some severe-strength winds that snapped tree branches and blew down power lines in Glen and Caraway, Arkansas. Harrisburg, Illinois reported 2.27 inches of rain, but most areas along the front saw between 1-2 inches of rainfall. Flooding continued to threaten most of the Midwest. As this system crept northeastward into New England, cooler temperatures allowed for some mixed precipitation of freezing rain and snow. This brought even more dangerous road conditions and many airports saw major delays. Winter storm advisories have been issued for the Northeast from New York state to Maine. Meanwhile in the West, another sunny and cold day prevailed over the California due to a dominant ridge of high pressure. Highs only ranged from 50 to 50 and overnight lows dipped below freezing, thus, another frost advisory has been issued over most of California. In the north, a trough moved into the Pacific Northwest, which produced cloudy skies with a few scattered sprinkles.

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