NATIONAL WEATHER SUMMARY

AUGUST 2016

1-6: Monsoonal thunderstorms continued to impact the Southwest on Wednesday, while a cold front brought stormy weather to the Southeast. A plume of monsoonal moisture lingered over the lower Intermountain West and the Desert Southwest. In the East, a cold frontal boundary stretched from the southern Mid-Atlantic to the middle Mississippi Valley. Moisture-rich air interacted with this frontal boundary, which lead to the development of showers and thunderstorms in the Midwest, the Tennessee Valley, the southern Appalachians and the Deep South.

Heavy rain affected portions of the Southeast on Friday, while monsoonal thunderstorms developed across the Four Corners. Meanwhile, a cold frontal boundary stretched southwestward from southeast Canada to the southern Plains. Showers and isolated thunderstorms formed along and ahead of this frontal boundary over parts of the Midwest and the Plains. Excessive heat warnings and heat advisories were issued for portions of the southern Plains, the Mississippi Valley and the Deep South. Hobart, Okla., recorded a midday high of 95 degrees with a heat index of 99 degrees.

 

7-13: Heavy rainfall and flooding persisted over the Southeast on Monday as abundant tropical moisture lingered over the region. West of this activity, monsoonal moisture over the Four Corners in combination with a trough of low pressure allowed for showers and thunderstorms to develop over Colorado, New Mexico, and eastern Arizona. Meanwhile in the Northwest, another low pressure system moved onshore and triggered rain showers across Washington and northern Oregon. Periods of heavy rainfall and areas of flash flooding are anticipated with this system.

A wet low pressure system in the Gulf of Mexico continued to pour deep moisture into the Southeast, producing widespread showers and thunderstorms. The heaviest of the rain fell along the coast from Louisiana through the Florida Panhandle, adding to the several inches of rain that has already fallen on the area. Meanwhile, monsoon moisture streamed into the Southwest from Mexico, which is fairly normal for this time of year. This moisture produce mostly scattered showers and thunderstorms in the Four Corners area, with some of these thunderstorms producing heavy rain. Seasonally warm temperatures greeted much of the country, as max temps warmed into the 90s and some 100s in the Southern Plains. The coolest afternoon temperatures were noted in the Northwest and Intermountain West.

The Southeast saw more heavy rainfall on Friday, while a frontal boundary created some showers and thunderstorms for the Northeast and Midwest. A low pressure system and tropical moisture lingered over the northern Gulf of Mexico and continued pushing abundant moisture into the Gulf States. Out West, monsoonal moisture lingered over the Four Corners and allowed for a few more afternoon showers and thunderstorms to develop across eastern Arizona and New Mexico. High pressure over the West Coast maintained dry and sunny conditions.

14-20: A low pressure area brought heavy rain to the Mississippi Valley on Monday, while hot and dry weather persisted west of the Continental Divide. Meanwhile, scattered monsoonal thunderstorms popped up across the central and southern Rockies, as well as the eastern edge of the Great Basin. Most areas west of the Continental Divide experienced warm and dry weather on Monday. Heat advisories remained in place for parts of southern California. Palm Springs, Calif., recorded a midday high of 105 degrees. Bullhead City, Ariz., recorded a midday high of 107 degrees.

 

Active weather persisted from the southern Plains to the Mid-Atlantic on Wednesday, while monsoonal thunderstorms developed across the Intermountain West. A low pressure area drifted over New England. A cold frontal boundary associated with this system stretched southwestward across the coast of New England, the Mid-Atlantic and the central Appalachians. Out west, monsoonal thunderstorms continued to pop up across the central and southern Rockies, as well as the Desert Southwest. Flood advisories were issued in parts of Arizona and New Mexico. Most of the West Coast experienced warm and dry weather on Wednesday. Excessive heat warnings and red flag warnings were issued in southern California. El Centro, Calif., recorded a midday high of 107 degrees.

 

Many areas of wet weather developed across the U.S. on Friday as multiple weather systems moved through the nation. A cold front triggered scattered showers and thunderstorms from the southern Plains through the upper Midwest on Friday. Moderate to heavy showers and thunderstorms developed from the Great Lakes through Texas. The back side of this system also allowed for heavy rainfall to develop across the northern Plains and northern Rockies.
To the south, warm and humid conditions allowed for shower and thunderstorm activity to persist for the Southeast and Tennessee Valley. Meanwhile high pressure built over the West Coast and brought warm and dry conditions to the West. Excessive heat advisories have been issued across the Pacific Northwest due to anticipated high temperatures ranging from 15 to 25 degrees above normal. Fire danger remained high across the West with these conditions.

 

Active weather affected the Plains and the Mississippi Valley on Friday, while a ridge of high pressure kept conditions dry across the West Coast. A handful of states across the central and eastern portions of the country experienced high temperatures in the 80s and 90s. Butler, Ga., recorded a midday high of 90 degrees. Daytime heating triggered monsoonal thunderstorms over the Four Corners. Most areas west of the Continental Divide experienced warm and dry weather on Friday. Heat advisories were issued for portions of western Oregon and western Washington. Portland, Ore., recorded a midday high of 81 degrees. Los Angeles, Calif., recorded a midday high of 76 degrees.

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