NATIONAL WEATHER SUMMARY

 

SEPTEMBER 2016

 

1-10: Post-Tropical Cyclone Hermine impacted the Mid-Atlantic on Saturday, while a cold frontal boundary shifted over the northern tier of the country. Meanwhile, a cold frontal boundary stretched southwestward the northern Plains to the Great Basin. As this frontal boundary transitioned eastward, it generated multiple clusters of showers and thunderstorms across the northern Plains, the central Plains and the Intermountain West. Flood warnings were issued in central Kansas. Flash flood watches were also issued in eastern Colorado and western Kansas. Just to the west, an area of low pressure brought scattered showers and cooler temperatures to the Pacific Northwest. Redmond, Ore., recorded a morning low of 34 degrees with a wind chill factor of 30 degrees.

 

A frontal system shifted across the northern tier of the country on Monday, while Post-Tropical Cyclone Hermine stalled out east of the Mid-Atlantic. A slow-moving frontal boundary stretched southwestward from the upper Midwest to the central Rockies. This frontal system generated multiple clusters of thunderstorms over the upper Mississippi Valley, the northern Plains and the upper Intermountain West. This cooler air mass supported high elevation snow showers in the northern Rockies. Pinedale, Wyo., recorded a morning low of 33 degrees. Meacham, Ore., recorded a morning low of 28 degrees. Meanwhile, monsoonal thunderstorms popped up across portions of the lower Intermountain West, the Desert Southwest and the high Plains. Most of the Great Basin and the West Coast stayed clear of precipitation.

Tropical Storm Newton impacted the Southwest on Wednesday, while a frontal system stretched from the Great Lakes to the central Rockies. Meanwhile, a stationary front stretched southwestward from the Great Lakes to the central Rockies. Multiple clusters of thunderstorms fired up along and near this frontal boundary across the northern Plains, the Midwest and the interior Mid-Atlantic. Additionally, a Pacific system brought light showers to northwest Washington. Most of the West Coast and the Great Basin experienced dry weather on Wednesday.

 

11-17:  A low pressure system moved across the Plains on Thursday, while Tropical Depression Julia affected the Southeast. An area of low pressure moved east northeastward over the northern Plains. This system and a cold frontal boundary produced multiple clusters of rain and thunderstorms across the Rockies, the Plains and the Midwest. Most states west of the Continental Divide stayed clear of wet weather on Thursday. Los Angeles, Calif., recorded a midday high of 75 degrees. Seattle, Wash., recorded a midday high of 58 degrees. Meanwhile, Tropical Depression Julia kept showers and thunderstorms in the picture for the coast of the Carolinas. Scattered storms also affected the Gulf Coast as a tropical disturbance formed over the northern Gulf of Mexico. High pressure brought cool and dry weather to New England on Thursday. Portland, Maine, recorded a midday high of 65 degrees.

 

A cold frontal system brought active weather to the central third of the country on Friday, while high pressure kept most states dry along the West Coast. Scattered showers continued to pop up along the southern Mid-Atlantic as Tropical Storm Julia lingered over the western Atlantic. Most areas across the northern Mid-Atlantic and New England experienced dry weather on Friday. High pressure also kept most of the West Coast, the Great Basin and the Intermountain West mostly clear of precipitation. Palm Springs, Calif., recorded a midday high of 95 degrees. Portland, Ore., recorded a midday high of 67 degrees.

 

18-24: A cold frontal boundary moved across the East Coast on Monday, while another frontal system affected the upper Midwest.  A cold frontal boundary extended south southwestward from the Northeast to the Gulf Coast. Rain and thunderstorms developed along and ahead of this frontal boundary over New England, the Mid-Atlantic and the Southeast. Locally heavy rain impacted the Mid-Atlantic as the remnants of Tropical Depression Julia moved over the region. Meanwhile, a separate frontal boundary generated showers and thunderstorms in parts of the northern Plains and the Midwest. Just to the south, heat advisories were issued for eastern Oklahoma and southeast Texas. Brownsville, Texas, recorded a midday high of 93 degrees with a heat index of 102 degrees. To the west, an onshore flow from the Pacific brought light to moderate rain to western Washington and northwest Oregon. Additionally, moisture associated with Hurricane Paine began to surge across the Southwest. Isolated showers and thunderstorms developed across the southern edge of California. Fire weather watches were issued in southwest California due to a threat of dry lightning.

 

Active weather impacted the Plains and the Midwest on Wednesday, while the remnants of Hurricane Paine moved across the Southwest. Meanwhile, a wave of low pressure brought showers and thunderstorms to the Mid-Atlantic. Out west, subtropical moisture associated with the remnants of Hurricane Paine surged across the Southwest. Scattered showers and thunderstorms developed in southern California, southern Nevada and the Four Corners. In addition, a trough of low pressure generated scattered showers over the Northwest and the upper Intermountain West. Cool air also accompanied this system. Meacham, Ore., recorded a morning low of 30 degrees. Stanley, Idaho, recorded a morning low of 35 degrees.

 

An area of low pressure shifted northeastward across the Intermountain West and the northern high Plains. A warm frontal boundary associated with this system extended eastward. This frontal boundary generated moderate to heavy rain and embedded thunderstorms over the northern Plains and the upper Midwest. Flood warnings were issued in southwest Wisconsin, southeast Minnesota and eastern Iowa. A cold frontal boundary extended south southwestward. Temperatures dropped 10 to 20 degrees below normal west of the frontal boundary. This cool air supported the development of high elevation snow in the northern Sierra Nevada, the Great Basin, the Wasatch and the Rockies. Truckee, Calif., recorded a morning low of 19 degrees. Evanston, Wyo., recorded a morning low of 33 degrees. Winter weather advisories were issued in northern Wyoming and northern Utah. Further to the west, a Pacific system approached the Northwest. Light to moderate rain developed ahead of this system over Washington and northern Oregon. Meanwhile, a wave of low pressure continued to produce scattered showers and thunderstorms along the southern Mid-Atlantic.

 

25-30:  A low pressure area drifted slowly across the upper Midwest on Tuesday, while scattered storms popped up over the Southwest. A robust area of low pressure moved slowly south southeastward across the Great Lakes. This system ushered rain and embedded thunderstorms over the upper Mississippi Valley and the Midwest. A cold frontal boundary associated with this system extended southwestward. This frontal boundary initiated showers and thunderstorms across portions of southern New England, the Mid-Atlantic, the Southeast and the Gulf Coast. Cool air trailed the frontal system over the northern Plains and the Midwest. Tioga Municipal Airport, N.D., recorded a morning low of 32 degrees.

Meanwhile, an area of low pressure generated scattered showers and thunderstorms across the Desert Southwest. Most of the Intermountain West, the Pacific Northwest and the West Coast experience dry weather on Tuesday. Parts of southwest California experience above normal temperatures due to offshore winds. San Luis Obispo, Calif., recorded a midday high of 98 degrees. Los Angeles, Calif., recorded a midday high of 93 degrees.

 

A low pressure system stalled out over the Midwest on Friday, while a cold frontal boundary shifted across the Northwest.  A slow moving low pressure system drifted over the Midwest. This system continued to usher showers and thunderstorms over states stretching from the upper Mississippi Valley to southern New England. Heavy rain and thunderstorms fired up along and near this frontal boundary from the northern Mid-Atlantic to the Southeast. Cool air trailed this system over the upper Midwest and the Northeast. Houlton, Maine, recorded a morning low of 28 degrees. Meanwhile, monsoonal thunderstorms persisted across parts of the Desert Southwest, the southern Rockies and the southern high Plains. Just to the north, a wave of low pressure generated several clusters of thunderstorms from the upper Intermountain West to the northern Plains.  Additionally, a cold frontal boundary drifted eastward over the Pacific Northwest. This system brought scattered showers and a blast of cool air to Washington and western Oregon. Burns, Ore., recorded a morning low of 33 degrees. Olympia, Wash., recorded a morning low of 37 degrees.

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