10-25-2019

Just a quick update;

Our warm up will peak today in the high country.  Expect highs mid to upper 60s today…

Then a strong dry cold front will sweep through Mammoth with breezy weather Saturday night followed by a temperatures drop of greater than 20 degrees Sunday over Saturday. Highs inn the upper 30s Sunday. Lows inn the teens Monday AM.  Temperatures will moderate next week…..

 

Looking at the climate model (longer range)  The Euro shows the Central Sierra near Mammoth picking up some 10 to 15 inches of snow by Sunday the 24th of November and amounts of 30 inches by the 8th of December.   Again this is a climate version of the EURO and is not a forecast, but rather an outlook over a long time scale. Will report next week at this time to see if there are any changes to this long range outlook.

 

More thoughts….

 

I had a closer look at the CPC Winter Forecast,  NDJ for Precipitation.

Grab a copy of the CPC on line, print it out and look at it.  Note the main bias area of below normal precip is from Monterrey CA to just north of the Northern California/OR boarder and inland to the Northern Sierra where the signal weakens as you go south down the Central Sierra. This is suggestive of a Winter-time Split Flow pattern, off the Northern and Central CA Coast, whereby storms split and favor the southern portion of the State.  It suggests that the Northern Sierra will have below normal precipitation with less of a negative bias as you go south. This means that Mammoth may actually fair better than Tahoe this winter snowfall wise.  Southern CA, San Diego and the Southern Sierra may do the best this winter, as far as a normal or even above normal amounts of precipitation.

PS. There may be some great Tonopah Lows as well this Winter, with great up-slope snowfall for the Eastern Slopes for parts of the Central and Southern Sierra! I will look at the update in November; for December, January and February later next month.

PPS. The retracted EAJ is famous for split flow patterns on the west coast during the winter.

So essentially, the low frequency base state mimics La Ninia. However, at times, the MJO may strongly modulate the westerlies, providing an Extended East Asian Jet to the west coast…….Periodically.

 

The Dweeber………………:-)

 

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Our beautiful weather will give way to breezy conditions over the ridges today and again the end of the week followed by much cooler weather and possibly a few snow showers during that transition Sunday into Monday.  This is a common pattern in late October.  Expect highs cooling to the 40s Sunday and Monday next week with lows in the teens in Mammoth Lakes Monday AM.

According to the CPC. (Climate Prediction Center) On a climate scale, the prospects for a wet winter look pretty remote this year. Their winter forecast suggests normal to below normal snowfall this winter for the Central Sierra..

Possible Reason…….A large scale circulation system over the Indian Ocean may affect the weather over the Western States this year as a Strong Indian Ocean Dipole (IOD)……. currently in place, causing above-normal sea surface temperatures in the Western Indian Ocean and below normal SSTs in the Eastern Indian Ocean and waters in proximity to the Maritime Continent. The atmosphere is responding to this boundary forcing with stationary enhanced convection observed for several weeks across Africa and the Western Indian Ocean with stationary suppressed convection observed from the Eastern Indian Ocean eastward across the Maritime Continent and into the West Pacific to near the Date Line.

This is important because if suppressed convection persists in the Western Pacific along with the absence of any organized large scale enhanced convection, the convection further east in the Pacific, tends to favor more frequent periods of a “Retracted East Asian-Pacific jet stream”. So in some ways, this may mimic a La Nina like conditions downstream over the CONUS  (US). For the western CONUS, this is a drier and potentially colder than normal scenario for Eastern California. The big problem, is, where will the cold air set up.  It is unlikely over the ocean, but more likely over the inter mountain west, more often than not. That will be the key out west. 

Other thoughts…..

The big warm blob of water earlier in the fall off the Northern CA coast has redeveloped further west at about 143 west.  This may further support sharpening ridges along this longitude for the import of cold air over the far west at times.

Solar Minimum….

The deepest solar minimum of the space age is upon us.  (No Sunspots) This is often associated with more high latitude blocking. Once again, where will blocking be persistent this winter?   Update later in November…….

 

Dr Howard and the Dweebs……………………:-)