Monsoon thunderstorms generally begin to develop across the Desert Southwest by mid July, spreading northward over the following month. In desert areas, the storms bring welcome rain but often cause flash flooding and haboobs (dust storms).
This year, persistent high pressure over the Desert Southwest has produced relentless sunshine and oppressive heat; it has also shut off the monsoon flow. By mid summer, high pressure over the Southern Plains usually combines with low pressure over the Baja region to sweep in moisture from the Gulf of Mexico and the Sea of Cortez, igniting the storms. There is some evidence this week that the high pressure dome over the Southwest is finally shifting eastward, allowing the humid monsoon winds to enter the Sonoran and Chihuahuan Deserts.
While the Southwest Monsoon generally reaches the Colorado Front Range during the second half of August, we have been receiving regular, late-day thunderstorms throughout July. These storms, in part, have resulted from the persistent high pressure over the Desert Southwest, which has shunted Pacific moisture to the north of the Four Corners region. Stagnant weather patterns often benefit one geographic area at the expense of another.
This year, persistent high pressure over the Desert Southwest has produced relentless sunshine and oppressive heat; it has also shut off the monsoon flow. By mid summer, high pressure over the Southern Plains usually combines with low pressure over the Baja region to sweep in moisture from the Gulf of Mexico and the Sea of Cortez, igniting the storms. There is some evidence this week that the high pressure dome over the Southwest is finally shifting eastward, allowing the humid monsoon winds to enter the Sonoran and Chihuahuan Deserts.
While the Southwest Monsoon generally reaches the Colorado Front Range during the second half of August, we have been receiving regular, late-day thunderstorms throughout July. These storms, in part, have resulted from the persistent high pressure over the Desert Southwest, which has shunted Pacific moisture to the north of the Four Corners region. Stagnant weather patterns often benefit one geographic area at the expense of another.
