DRY THANKSGIVING WEEK…STRONG SIGNALS OF A DECEMBER RETURN TO WET

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SUMMARY
Dry and mild through Thanksgiving week. A brief cool down midweek will be followed by a warm weekend. Then, model consensus is building that a pattern shift to wet is around the corner.

TUESDAY AND WEDNESDAY
A brief cool down into the 50 and 60s as a weak low pressure trough moves across Northern California and the Pacific Northwest. (Image 1)

THURSDAY AND FRIDAY
By late in the week, through the weekend, high pressure will push back in, warming temperatures back into the 70s in most areas. (Image 2)

WARMUP LATE IN THE COMING WEEK
This will cause a warm up across the region, with temperatures above normal for late November all across the West. (Image 3)

DRY THROUGH NOVEMBER 30TH
All of this will keep us dry through the end of November. (Image 4)

CHANGES AHEAD
By the first days of December, a subtle change is forecast, with the high pressure ridge dominating the West flattening and becoming less amplified. (Image 5)

That will open the door for changes. A low pressure trough may push in toward the end of the first week of December. (Image 6)

ARRIVAL OF STORMS?
By December 3rd, ensemble guidance hints that storms may push further south, toward Central California. (Image 7)

The GFS shows a storm for the 7th, and another close behind. Really too early to forecast actual storms, but a nice sign. (Image

STRONG MODEL SUPPORT
What’s nice about this pattern change is that it is being seen by all major forecast models. And, it is supported by a strengthening East Asian Jet Stream that should help flatten the ridge and bring us a westerly, zonal flow. (Image 9)

Another hopeful sign is the trend of the Pacific North American (PNA) pattern. This teleconnection pattern tracks atmospheric pressure across the North Pacific and North America. It is moving from a positive into a negative phase (seen by all models), which usually corresponds with a low pressure trough and stormy weather for the West Coast. (Image 10)

This change to wetter weather is also being seen by the CFS weeklies, another positive development. (Image 11)

All to say, enjoy a sunny and mild Thanksgiving Week with the knowledge that a change to wetter weather may be just around the corner, in early December. We’ll keep you updated!