NATIONAL WEATHER SUMMARY

 

OCTOBER 2012

 

1^st-6^th…Chilly Fall temperatures spread into the East as a low pressure system in Canada pushed a cold front eastward throughout the day. The front kicked up scattered showers and thunderstorms as it stretched from the Ohio River Valley, through the Midwest, and into Arkansas. Rainfall totals ranged around 1 inches across most of the frontal boundary, while wind gusts ranged from 20 to 30 mph in some areas. Temperatures dropped by 10 to 20 degrees as this front passed, with highs in the Midwest remaining in the 40s and 50s, while the Southeast and Mid-Atlantic states saw highs in the 70s and 80s. Behind this system, a cold trough of low pressure slid southeastward from the Rockies, into the Central Plains. This system triggered a few scattered snow showers as it moved eastward throughout the day. Snowfall accumulation ranged from 1 to 3 inches in parts of Wyoming, Colorado, and into western Nebraska. In the South, the tail end of a cold front lingered over Florida. This system produced a few more showers and thunderstorms, but severe thunderstorms and heavy rains were not anticipated.

 

7^th-13^th…Cold air continued to pour into the East, while rain showers spread across the Great Lakes and Northeast on Wednesday. A low pressure system spinning in eastern Canada continued to push a cold front eastward. This system moved from the Great Lakes, up the Ohio River Valley, and into the Northeast, and triggered scattered rain showers throughout the day. This system also brought cooler temperatures to the region, with overnight lows in the 30s and daytime highs in the 50s. The tail end of the cold front extended into the Tennessee Valley and Lower Mississippi River, but rainfall has not yet developed in these areas. Behind this system, a trough of low pressure moved into the Northern Plains from Canada and produced a combination of snow and rain showers. Cold air continued to pour into these areas, with overnight lows dropping into the upper teens across the Northern High Plains. Daytime highs only reached into the 30s and 40s across the Dakotas and parts of Minnesota. Out West, a low pressure system off the coast of California advanced eastward and pushed some moisture onshore. This kicked up scattered showers across parts of central and southern California, and increased chances of thunderstorms across the Desert Southwest. Rainfall totals remained less than a tenth of an inch across the region.

 

15^th-20^th…A pair of storms affected the country on Monday. The strongest of these storms began the day over the Great Lakes before moving into eastern Canada. The associated cold front stretched through the Northeast while also arcing into the Southeast. This front did not have a lot of moisture associated with it, but it did produce a line of showers and thunderstorms through the Southeast and into the Mid Atlantic. As the day progressed, however, rain gradually diminished because the front was cut off from its moisture source in the Gulf of Mexico. By late afternoon, rain was limited to the Northeast from Maryland through eastern New York.

 

The second storm moved through the Pacific Northwest and into the Northern Rockies. This storm also did not contain much moisture and only produced light to moderate rain from Washington and Oregon through Montana. The rest of the country was quite dry, while California and the Southwest continued to be unseasonably warm. Areas in the Southwest once again rose into the 90s due to a high pressure ridge over the region. The Northeast rose into the 60s and 70s, while the Southeast will see temperatures in the 70s and 80s. The Plains rose into the 70s and 80s, while the Southwest saw temperatures in the 80s and 90s.

A wet and very windy weather pattern gripped much of the central U.S. Wednesday afternoon as a storm system pushed into the Upper Midwest and the associated cold front reached from the upper Mississippi Valley through the southern Plains. This system met with plenty of moisture from the Gulf of Mexico, allowing areas of showers, periods of heavy rain, and thunderstorms to develop ahead of the advancing front through the afternoon. Meanwhile, behind this system, very strong winds swept across areas from the Northern Rockies through the Northern Plains and southward through parts of the Central Plains and the Central High Plains as high pressure began to build into the Northwest and tightened the pressure gradient across the region. Theses areas remained under various Wind Advisories and High Wind Watches and Warnings through the evening in anticipation of sustained northwesterly winds of 30 to 40 mph and winds gusting to 65 mph.

Active weather continued for parts of the East on Friday, while rain spread across the Northwest. A strong low pressure system over the Great Lakes slowly advanced eastward and pushed a front into the Northeast. This kicked up thunderstorm activity with heavy rains and strong winds from Pennsylvania to Maine. Rainfall totals surpassed 2 inches in parts of Pennsylvania in the early morning hours. A mid-day total of 3.61 inches of rain was reported at Mt. Pocono, Pennsylvania. Behind this system, lighter and more widespread showers persisted for the upper Midwest and Midwest. Strong winds also continued along the back side of this system with gusts from 40 to 50 mph across the Northern Plains and Upper Midwest. Yankton, South Dakota reported 51 mph wind gusts in the early morning hours. Severe storm development has not been reported across the Midwest or Northeast on Friday, but the system has a history of large hail, heavy rainfall, and damaging winds. Meanwhile out West, a low pressure system over British Columbia created a cold front that moved through the Pacific Northwest. This system pulled in moisture from the Pacific Ocean and allowed for scattered rain showers to develop, which turned to snow at high elevations of the Cascades. Precipitation from this system advanced eastward into the Intermountain West as the system moved eastward throughout the day.

21^st-27^th…Relatively benign weather greeted much of the country Wednesday. Perhaps the strongest storm in the country was a Pacific storm that slammed into the West Coast and renewed rain and high elevation snow from Washington through Central California. This precipitation was on top rain and snow from earlier in the week, switched caused travel problems and even spawned some tornadoes.

Farther to the east, a front moved through the Plains and Upper Midwest, but it was lacking in significant moisture that other storms in the region have had in the past. Instead a mix of rain and snow fell from the higher elevation of the Rockies through Minnesota. Elsewhere, a high pressure system along the eastern seaboard continued to provide dry conditions from Florida through Maine. Meanwhile, Tropical Storm Sandy strengthened into a hurricane as it slammed into Jamaica. She was expected to move over eastern Cuba before moving into the Bahamas. The reason to mention Sandy is because she may become a problem for the Northeast early next week as she could curve back toward land. The Northeast rose into the 60s and 70s, while the Southeast saw temperatures in the 80s and 90s. The Southern Plains rose into the 80s and some 90s, while the Northwest saw temperatures in the 40s and 50s.

Hurricane Sandy was at currently at Category 1 Hurricane strength with maximum winds up to 75 mph on Friday, and moved northward from the northern most islands of the Bahamas. The system produced heavy rains with strong winds and dangerous surf just off the coast of eastern Florida and the Carolinas. Flow around this system pushed some heavy rains into eastern Florida and the eastern most regions of the Carolinas. Rainfall totals ranged from 1 to 3 inches in these areas on Friday. Strong winds have been reported from 45 to 55 mph across eastern Florida. To the north, a low pressure system in Canada continued to push a cold front eastward through the Great Lakes and stretched down the Ohio River Valley and into the Lower Mississippi River Valley and eastern Texas. Showers and thunderstorms developed along and ahead of this front, with heaviest rainfall reported up to 1.92 inches in Shreveport, Louisiana. Cool air poured in behind this system with highs ranging in the 40s as far south as Oklahoma and the Mid-Mississippi River Valley. Meanwhile in the West, a low pressure system pushed another cold front onshore, producing rain and mountain snow showers for the Pacific Northwest, Intermountain West, and Northern Rockies. Hot and dry conditions over the Southwest increased fire danger across southern California and into Arizona.

 

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