Beautiful Clear Day Monday will Give Way to some smoke Tuesday….Then Better Air Quality Wednesday…..PNA Pattern to break down this weekend, leading to better weather for the fire fighters

9:45 PM Monday

Monday nights Rapid Refresh Smoke model really pushes the smoke back into Mammoth during the afternoon hours Tuesday….More hacking and coughing ahead….

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The highly amplified pattern across the pacific and North America, responsible the for heightened fire season is still in play.  This is actually +PNA Redux. Its a very similar pattern that developed back in early September, when the Creek Fire started. The late August through early September +PNA that developed was epic in strength, as far as positive height anomaly over CA. (601dm) for those dates.  It was truly a hybrid between the Eastern Pacific High and the Subtropical Contential High at the time.  The net result was a small upper jet that developed along the western flank of the upper high along the CA Central coast. It moved up the coast and set off a lightening storm that the Bay Area and Northern CA will long remember. That storm was respondsible for the fires along the Central and Northern CA coasts.

The current pattern is minor in comparison, but is still similar in some respects. The main height anomaly is further north, so Mammoth does not get the heat, The strongest winds are over Northen Ca and are respondsible for the fires over NAPA and north. It should be noted that, the down stream effect is a cold eastern trof that the east is dealing with.  Additionally, meridional flow is playing havoc in europe with very chilly temperatures in the Alps and France.

The Current highly amplified pattern of ridge/trof, (+PNA) will break down this weekend.  By Monday a week away, a strong belt of westerlies pushes into British Columbia. Underneath the westlelies, California is still under fairly high heights at 500MB, so temps are likley to remain a bit above normal with highs in the low 70s by Monday. Lows in the 30s. With any westerly flow, well likely get smoke from any fires that are buring to our west or SW.

Looking at the ECMWF Weeklys; (long range) looks drier than normal right on through October.  It does show some polor jet related storminess the first half of NOV.  I usually take this with a grain of salt as climate models do not do very well in September and October.

Some minor changes in the ridge pattern will allow Signifacant smoke back into Mammoth Tuesday. The upper height anomaly splits in half with slightly higher heights to the south. This will be enough to create light SW flow Tuesday and import some smoke from the Creek Fire back into Mammoth. By Wednesday, higher heights once again develops to the north and the flow backs again to the NE, later in the day Wednesday. That will tend to push the smoke back west again late in the day Wednesday. Overall,  Still looking for a very warm remainder of September/Oct week head. Not much change through the middle of next week as well. However, the GFS is showing some subtropical moisture moving into Central and Northern CA about the 9th of October. That may bring some light rain to our area.  Updates on that next week.

 

 

Dr Howard and the Dweebs…………………..:-)

Summer goes out on a quiet note and Autumn Equinox arrives at 6:31 AM Local time Tuesday…..Some Increase in SW breeze this week then Quiet weather Wednesday and Thursday with more breeze Friday……Another heat spell on the Horizon…

The Tempo really picking up in the long range with potential for record high temps early next week and more critical fire weather, Beginning Sunday and well beyond…….See discussion from two days ago below.

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Today is the last full day of Summer.  Like many days of 2020, I am looking forward to getting on with the Fall and Winter.  Cooler days and eventually Snowfall will put an end to the Smoke from the Creek Fire. There is no telling how many people have been affected by the long term effects of the smoke and hazardous air quality throughout Mono County This Summer. Those PM 2.5 smoke  particles are toxic to everyone.

The first couple of days this week are highlighted by the effects of Trofing in the GOA and Pacific NW. Expect more SW breeze today and tomorrow Tuesday with a fairly Calm Day wind wise on Wednesday. No doubt that there will be more smoke from the Creek Fire…..Early this week.   For Wednesday, there is a small upper high over the top of us bringing us a warmer day. Another Trof moving into the Pacific Northwest Thursday will bring an increase of wind Thursday afternoon into Friday. This does not look like a wind event. We could still have winds in the 25 to 35 MPH range.

 

Longer Range:

The Dweebs are watching a tropical storm in the western pacific #14. The global models spin up this system later this week, and constructively phase with an approaching trof coming off Asia this weekend. The down stream effects are;  amplification of the downstream upper air pattern with a deepening Trof just east of the dateline and strong ridging in the Eastern Pacific. This ridge is progged to  build into California later Saturday into Sunday and Monday.  If this scenario sets up, it may be similar to early September when hot temperatures developed over CA. This pattern is not as extreme for CA as early in the month as it will be late September and early October by then. Nevertheless, Offshore flow (Santa Ana winds) are indicated and hot weather will develop again in parts of the state and especially Southern CA. Sunday into Tuesday, the end of the Month. “This is an outlook at this time, not a forecast”

 

Upper 70s or low 80s in Mammoth may be in our future next week….Nights will still cool into the 30s..

 

Dr Howard and the Dweebs………………:-)

Light Rains Overnight brought Air Quality Relief and Lifted Spirits of Residences of Mammoths as Creek Fire’s growth slowed….Upper Jet and Surface front still concerning this afternoon…..Creek fire smoke still in our future…

Residents of Mammoth woke up to a pleasant surprise with a light rain falling from our skies.  Moisture from remnants of tropical depression Karina was channeled across, mainly Southern Mono County, bringing 1/4 inch of rain as measured by the RAWs site at Devils Post Pile. The rain had stopped, however, the airmass continues to be moist for the time being. The models’ did forecast the past few days, some precipitation in this time frame, however, no where near a 1/4 inch.  As a rule, models do not handle subtropical moisture well from the SSW.

The big story is still the smoke and the upcoming windy period expected later this afternoon. Yesterday, gusts of 25 MPH were common over the summit of Mammoth Mt during early afternoon. By 8:45pm, the winds were gusting to 60 mph. However, the gradient driven winds at the surface during that afternoon did not materialize as smoke blocked the diurnal solar heating of the day.   This is an area, I think that the NWS does not have a complete handle on as there is little experience with this much smoke ahead of a subtropical jet. However, live and learn and the forecast will be better next time with the wind portion.  (Of course we all hope for not a next time)

Fridays afternoons winds should surface, as they will be dynamically driven by a weak branch of the polar jet and surface front. Strong gusty winds are expected later this afternoon in town in the 30 to 50 MPH range.  Once the front passes through, our airmass will dry out again tonight.

The outlook for the weekend is for continued westerly flow. Inversions will eventually set up again and yes, the smoke will thicken with amounts dependent upon the fires activity.   Temperatures this weekend will cool to the 60s for highs and down possibly to the 30s. Wind’s will be light Saturday.

Looking down the road;

Next week through Tuesday we will be under a westerly flow, with the upper jet well to our north. Temps will rise to the low 70s again with lows in the 30s and 40s.  There is more ridging Wednesday before a short wave Trof breaks it down. So Wednesday may be warmer with lighter breezes, possibly more smoke. There may be more breeze Thursday afternoon and night followed by NW flow Saturday a week away.  Beyond that, another good sized ridge builds in about next Sunday into week 2 with the possibility of an off shore event that might actually clear us out! That’s a long way out and as you know, Forecast Models’ are not perfect, just forgiven!

 

Dr Howard and the Dweebs……..:-)