3/28/23

 

Update from the CPC this afternoon:

 

Following a robust Madden Julian Oscillation (MJO) across the Western Hemisphere earlier in March, the intraseasonal signal has since weakened as it moved over the Indian Ocean during the past week. The GEFS and ECMWF dynamical model ensembles are in good agreement regarding a weakened MJO signal for the next week followed by renewed strengthening across the Maritime Continent and Western Pacific in early April. This could lead to an extratropical response typical of La Nina, possibly leading to above normal temperatures over the eastern and below normal temperatures western contiguous U.S. during April.

This also means that periods of unsettled weather is a possibility during the month of April for the Sierra.

__________________________________________________________________________________________________________________________________________________________________________________________________

March 27th

This mornings forecast maps showed a rapidly spinning up low pressure system off the Columbia River. There is a good subtropical tap and it appears that this storms Bullseye will be Mammoth south to the Northern portion of the Southern Sierra. Between 1 and 2 feet is possible at the Village at Mammoth and 2+ to 3 feet over the upper elevations. Most of this will occur Tuesday night into early Wednesday AM. The best break wil be Friday into Saturday with winds on the increase Sunday and more snowfall possible late Sunday night into Monday. This following storm is quicker moving and does not have any subtropical tap, so 3 to 6 inches in town and 6 to 10 inches over the crest seems reasonable.  PS, this is a cold pattern and snow to water ratios are at least 12:1 or better,

Longer Range: 

After the Monday system moves through, it looks cold, showery and breezy to windy Tuesday and Tuesday night with little in the way of any meaningful snowfall.  Wednesday looks cold with a slight chance of snowshowers.

Then we get into a bit of a change in the pattern over the pacific, where the Eastern Pacific High retrogrades somewhat. It will be April by then, and at this point in time, more speculative forecasts because of the month. I think the bias in the models that time of the year is to go weaker with storms. However, this is a very unusual year!  If it was just 2 or 3 weeks ago, I know we would be looking at a few large storms!  In fact there are at least 3 good sized systems.  The upper ridge in is the right place for good over water trajectory, but at the moment, the storms bottom out to the north and west of us. Clearly, more time will be needed to see which way this is all going to work out.

Just Updated:

As an updated side note, the Climatic Prediction Center has indicated today that Weak to Moderate Ridging is over the North Pacific with Trofing located over the Western US.

It was indicated that, “As the forecast period progresses during week 2, these anomalous features “Weaken as the 500MB Field trends toward climatological normals”.  This means that storms will be weaker during the week 2 period.  

 

 

Dr Howard and the Dweebs……………………….:-)