The Blanca Monsoon

Blanca, initially a hurricane off the coast of the Baja Peninsula, has moved into the Desert Southwest as a Tropical Depression, bringing copious moisture to Southern California, Arizona and New Mexico.  In many ways, this moisture flow mimics the annual Southwest Monsoon, which generally begins by mid summer and brings flooding rains to the Southwestern Deserts and Four Corners region; by late July or August, the monsoon moisture reaches the Colorado Front Range, igniting late afternoon thunderstorms.

Blanca's moisture will reach Colorado as well, interacting with an atmospheric trough that is dropping through the High Plains; as a result, cloudy, cool and rainy weather is forecast for later this week.  Fortunately, the disruption of sunshine will be brief; unfortunately, Blanca's remnants will aggravate flooding across the Platte River watershed.

Though moisture from Blanca will produce limited benefits in California, where an intense drought persists, it is not unusual for hurricanes and tropical storms to put an end to droughts across the Southern Plains and Southeastern States, especially when blocking highs or stationary fronts slow their movement.  Indeed, when it comes to rain-making, there's nothing like the deep moisture of a tropical system.