2-17-2022

Although not conclusive, an increasing number of Ensemble Members of the GFS are trending toward an undercutting scenario in the week 2 period which extends the outlook period through the 2nd day of March at this time.  The way the pattern is set up over the EP, there are two ways to get a good wet storm into CA.  One is retrogression, whereby the eastern pacific ridge builds back toward the date line allowing for extended SW flow to set up to the east of the Long Wave Axis. The other way is El Nino style, whereby a strong upper jet undercuts a highly Amped, full latitude ridge in this case, along about 140W that pinches off over the State of Alaska, while the westerlies undercut the ridge into the Central West Coast…..

The MJO can simulate El Nino for a short period of time….in the right location. So a Pseudo El Nino State.

The key I think to continued storminess, is whether the MJO stays strong enough, enough to continue constructively interfering with the La Nina Base State, after it emerges out over the West Pac. It is possible that the mid latitude westerlies remain active for an extended period into March, if the forcing continues.  As always, time will tell.

The Dweebs are having lots of fun with this.   Remember, these outlooks are not part of what the National Weather service does. The National Weather Service saves lives every day….I do not.  For important planning, always adhere to what they forecast in both short, medium and long range.   I am a hobbyist and as such, enjoy sharing my thoughts about what I see and understand. 😉

 

The Dweeber…….:-)

 

_____________________________________________________________________________________________________________________________________________________________________________________________________________________________

2-16-2022

Quite the amplified pattern with cold California sliders expected again early to mid week next week.   Were not through with this pattern of cold CA sliders over CA.  After a warmup into the weekend, another series will affect our weather 1st half of next week.  A a note, this pattern will actually favor southern CA more with better chances of rain as upper flow bows off shore early next week and brings a better chance for wetting rains to that region.

The Dweebs are still waiting for the Extra tropical response to the MJO over the Indian Ocean for the very end of the month and into the 1st week of March.  There is still the chance of a good wet storm for CA due to the MJO!

SEE the CPC post from yesterday;

Following a weakening of the Madden Julian Oscillation (MJO) during late January, enhanced convection has developed across the Indian Ocean in response to increased equatorial Rossby Wave Activity. This favors a reemergence of the intraseasonal signal, with the ECMWF and GEFS ensembles depicting eastward propagation of the signal toward the Maritime Continent and far Western Pacific during the next 2 weeks (RMM phases 3-5). The JMA, however, meanders the MJO in phase 3 with little eastward propagation. While there is some uncertainty in how far east the MJO propagates, its emergence over the Eastern Indian Ocean is expected to constructively interfere with the ongoing low frequency La Nina signal. This favors an atmospheric response typical of La Nina across the “extratropical regions of the Pacific and North America during late February and early March”, with relatively warmer conditions becoming increasingly likely over the eastern half of North America.

Of Note;

The evolution of the pattern seems to be one toward the undercutting of the westerlies the very end of the month of February into the first week of March. This is associated with a strengthening mid pacific, upper jet later this month and appears to be the trend of the global models during week 2. With this pattern, a mid latitude upper low can get squeezed underneath a blocking high in the -EPO Region, (Alaska) into California.  There may be some kind of AR associated with it……Time will tell.

 

Dr Howard and the Dweebs………………:-)

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Retrogression has taken place in the Western Hemi Pattern of late. The first in a series of California sliders is moving through the state. The core of the low at this time is north and west of Mammoth and still over land, It will  bring light snowfall today to the high country. Expect in varies areas of Mono County, general amounts in the 1 to 6 inch range. Another such system is being forecasted about the 20th.   Even though we are expecting light snowfall, this is still a dry one with the main low pressure storm track N/S over California, while the long wave axis is east over the Great Basin/Rockies and not over the Eastern Pacific. It will take more time for it to get there but I believe it will.  In the meantime, any one of the short waves have the potential to dig a path a bit more west along the coast. That scenario would be good for more snowfall and better chances for wetting rains for Southern CA.