Weather to Start Out the New Month

There will continue to be no significant changes in the weather pattern for the PNW. The high pressure cell parked of the west coast, will run the storm track well north. A weak disturbance will slide down the coast late Monday providing some light moisture for the mountains. Cool, dry and sunny conditions return on Tuesday and will likely carry on for the remainder of the week.
The high pressure cell will back off the coast on Monday, this will allow cool northern air to flow in early Tuesday morning. Thus, expect the first serious frost of the season. Watch for 3000’ – 4000’ freezing levels during the middle of the week. Warmer temps expected to return on Thursday.

Tuesday mornings MM5 (850mb) forecast model showing cool northerly flow.

This week in weather

There is not much change after this morning's small marine air assault. The central Cascade Mountains will return to dry weather for the rest of the week, and presumably well into next week.  Temperatures will begin to feel more seasonable as cooler air drives south, care of a low pressure system circulating in the Gulf of Alaska.   If you like rain and or snow, you will need to take a trip north to the Alaskan coast.  They are getting plenty of precipitation.  

This Week in Weather

This remarkable late summer weather will continue at least through the weekend. A high pressure cell centered directly over the inland northwest will keep us with dry and unseasonable warm temperature through the weekend. There are some intriguing changes to keep watch on beyond the weekend as a stronger trough digs further south early next week.

850mb model for next Tuesday Sept 25th. Notice the cold (purple) air driving south from the Aluetians chain.  This pushes the high pressure south of the PNW coast.  Not sure what this feature will ultimately bring, but it is something to watch.

A Weather Brief for Today

During the next 6-10 days, the North West will experience amazing fall weather. This is due to a large high pressure cell occupying most of the north pacific.  This high pressure cell is expected to continue to push all storms north into Alaska for the long term.   Excellent weather to get into the mountains an out of the smoke.

Let's Talk Climate

El Nino or not? NOAA’s monthly climate analysis came out last week. Below is a scaled down review. If you want the whole anchalata go to:

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml

The watch for El Niño conditions to develop continunes. The summer, (fall equinox) is expected to close with “neutral” conditions. However, there are continuing signs of an imminent transition towards El Niño. With out getting bogged down in the manusha of dynamic models vs statistical models, the official word is that weak El Nino conditions are likel to form early this fall and escalate to moderate through the winter.

General El Nino effects:
During El Niño, the northern tier of the lower 48, as well as southern Alaska, exhibits above normal temperatures during the fall and winter, while the southern tier experiences below normal temperatures during the winter season.

During El Nino events, increased precipitation is expected in California due to a more southerly, zonal, storm track. Increased precipitation falls along the Gulf coast and Southeast due to a stronger than expected, and more southerly, polar jet stream. In the late winter and spring during El Niño events, drier than average conditions can be expected in PNW.

Snow Fall:
During an El Niño, snowfall is greater than normal across the southern Rockies and Sierra Nevada mountain range, and is well-below average across the Upper Midwest and Great Lakes states. During a La Niña, snowfall is above normal across the Pacific Northwest and western Great Lakes

Stevens Pass Mountain Weather

Fall is clearly in the air. Freezing levels dipped to 5500’ this morning with the first strong cold front that passed through in months. The higher peaks certainly received their first dusting snow. It is that time of year to look for that shift in weather patterns that commits us to fall. Typical of early seasonal weather patterns, trends tend to be chaotic, providing occasional commitment to the up coming season.


This week will be follow that early season pattern by starting out cold and unstable. Low level clouds will stick to the Cascade Crest through tomorrow. High pressure will reestablish itself tomorrow allowing skies to clear, and temperatures to rebound into the 60’s or low 70’s by the end of the week. The long term weather models indicate a dry weather pattern lasting well into next week.

Ahh Fall.

To all you PNW mountain folk out there. I will start posting a weather perspective here.  I should have one up later today.