TC Mario could very well get tangled with a mid level cut off low and upper level trough and at minimum bring rain to South Ops.
In addition, due to an exceptionally warm blob of water being shoved south east by the ongoing troughing occurring across the west, a tropical cyclone-low pressure interaction could lead to enhanced convection as the much cooler air aloft interacts with warmer SST at the surface. This along with a tropical airmass would lead to instability. Worth monitoring for now.
What are the chances this hugs the coast into Ca?
Statistically always low. Models are struggling with it Really have to wait until it is more established. Some model runs show surface high-pressure building into the great basin at the same time as it moves up the coast. At bare minimum it gives us something to watch. HWRF seems to have the best handle on it.
Almost like the setup we had prior to the River Fire where lightning traveled through SLU/BEU/SCU right?
By tomorrow, the models should better understand the storm structure. Struggling with it because of the uncommon setup and track. If the storm is more of a middling/weaker to the west it could bring a lightning bust with the mid level moisture, but if it deepens and takes a further north track it could bring fire season delaying precipitation to a lot of the state.
Seeming for now to be a 50/50 chance for either solution. Late September lightning seems to favor SOPS and coastal areas.
Will be interesting to watch how it plays out. Right now there is also a trough shown to sweep into the PNW at the end of the run.. if the moisture is present and the low swings through could be a a several day precip event in far NOPS…
For some comedic relief from it all… The 18z GFS is probably the funniest model run I have ever seen. Needs to be framed. 
If that were to verify.. that is why we can’t have nice things in Ca..
One of these days one of these morbid scorpio minded 384 hr GFS runs is going to verify.
Let’s hope not!!!
Are you talking offshore and the hurricane? Lol
Yes the monster offshore wind event and 5 hurricanes hahaha
From NWS LOX AFD
“One possible caveat for Tuesday is that the 12z NAM was much more
aggressive with the return of monsoon flow and was hinting at an
earlier start to the convection with CAPE values over 1000J/kg,
mainly over the coastal waters. This could be a potential dry
lightning risk since the deeper monsoon moisture will still be
south of the area. While a few of the ensemble solutions showed
showers as early as Tuesday across our area, most were were still
favoring Wed or Thu as the more likely start to possible
convection locally.”
It is increasingly likely that deeper moisture will be advected off of the monsoon gyre/redeveloping Mario, but before that happens the initial warm front could bring dry lightning as the low levels remain dry. It is a difficult forecast. Both the EC and GFS ensemble means bring measurable precipitation… but how much and where is too broad to pin down.
Your insights tonite remind me of a little green critter who famously said.. “Difficult to see. Always in motion is the future” 
Well… it is a wild ride so far….pretty dramatic swings in outcomes !
SPC:
…Dry Thunderstorms…
As the western upper ridge builds, a subtropical disturbance will
approach southern CA D4/Wednesday. Accompanying this feature,
mid-level moisture and increasingly strong southwesterly/southerly
flow will overspread much of the West through the end of the work
week. This could support isolated to scattered thunderstorms with
lightning potential into the weekend. However, models vary on the
degree of moisture and strength of the upper ridge, casting
significant uncertainty on the dry thunderstorm potential midweek
and beyond.
The models often struggle during shoulder seasons. What is weird is that I would not necessarily consider this time of the year as a shoulder season. “Normally” this time of the year is one of the easiest to forecast… it is all about troughs and ridges and periodic offshore flow.
The existence of tropical storm remnants is usually present in August and September. As these systems move out of warm tropical waters they lose their energy but the moisture remains intact. The moisture is then available to be caught up in either HP or LP and advected into the state.
When we have a passing trough to the north, that moisture can be entrained into the trough which may be moisture starved, and then drawn into the state. This creates a difficult scenario to predict. That is why you may see a lot of vague language which seems to mention both wet and dry storms.
A passing trough or a cut off low can act similarly to entrain moisture and wring out some impressive totals at times.
These types of events have a large”boom/bust” profile.
On a more broad perspective…. The cool SST temps all year have seen a rapid change to warmer off the coast… especially near the PNW. The jet stream has been very active this year so far. If that continues and the warm blob sets up in the wrong place we could have an above average offshore wind season. If it moves just a little north and west… we could see an undercutting pattern where storms pile into the west coast. In a typical La Niña year we would expect early and robust storm series in the PNW.
I will look to the real weather folks on the page to dial in the forecast… and PDS.
Will be interesting to watch how it plays out.
Nice explanation, easy break down for the people.
Mario has deepened to 993 MB and thus because it is deeper it is running on the right side of the forecast envelope. The deeper the storm the tendency for it to move further to the right or a “poleward” motion. The hurricane models have shifted the circulation further to the east in the general area of Southern California, and especially on the HWRF shows a nice interaction with the upper level low essentially bringing a subtropical mid latitude cyclone off the coast as they combine the elements of cold and warm air. I think with the stronger trend Mario is showing, we should see significant precipitation potential in South Ops. The storm has picked up extra moisture on its journey to near hurricane status.
We have not had the effects of Mario yet but still thinking ahead. Models in pretty good agreement that Narda could form and bring additional moisture to the area later next week. HWRF most aggressive. Highlighting this because the US Navy model has done a pretty good job with Mario and 96E so far and is hinting that a third storm could form further to the east which matches up with the GFS ensemble . Mario and likely Narda set up an Ekman current along Baja. Fire season in jeopardy. (not that we had much of one going)
How far north will be getting substantial rain Bakersfield, Fresno etc?
