Our next weather maker is bringing the rain and cooler temperatures.
An area of low pressure with a cold front is advancing toward Colorado. This low is drawing in southwest wind speeds in the breezy category of 15-25 mph through Wednesday. This new weather pattern is also drawing two other elements into our region. The first will be a little more smoke and haze. The second will be subtropical moisture from the EPAC. Our departing high pressure system is also adding it’s own source region of moisture, but to a lesser extant, from the Gulf of Mexico. Both rain source regions will allow the Western Slope to achieve multiple rounds of showers and thunderstorms from late Tuesday through early Friday. Hazards will include lightning, hail, gusty wind speeds and of course flooding issues. A Flash Flood Watch will go into effect Wednesday afternoon through Thursday evening. An expansion in terrain is anticipated for this flood watch. Of course the timing on the departure of this weather maker is still uncertain, but as of today there is an expectation that storms will begin impacting the Grand Valley/Uncompahgre Valley by Wednesday evening and conclude by early Friday.
Temperatures will also dip significantly because of the artic airmass associated with this low pressure system. Average high temperature for this time of the year in Grand Junction is in the lower 90s. Montrose, CO generally achieves middle/upper 80s. A ten degree swing from the average is expected during the rainy weather (WED & THURS) and very little adjustment back to the average high is expected until early next week. Snow capped peaks may emerge from this storm system Friday, but we are talking about the top of the tallest Colorado peaks.