Archive for September, 2020

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……..:-)

 

 

Extremely Hazardous Air Quality Conditions continue throughout Mono County…..Cold Front approaching Mono County Thursday…..All eyes are on the Weather!

  1. If you weren’t able to tune in to last night’s community presentation about the Creek Fire, you can view it here: https://www.facebook.com/townofmammothlakes/videos/685327858759647
  2. Its been reported by other media sources that the Creek Fire has burned over 220,000 acres.
  3. Great Basin Monitoring had extremely hazardous air quality conditions for Mammoth the past few days. It appears that best air quality is around the noon hour. See:  https://www.gbuapcd.org/cgi-bin/tabularViewer?siteName=AirVision/Mammoth%20Lakes
  4. For up to date information on the Creek Fire, go online to:  https://on.mono.ca.gov/creekfire

 

Discussion:

Although our air-mass remains unseasonably warm, little in the way of anomalous warmth is reaching the surface in many areas of Mono County. The reason? Smoke. Smoke has extensively limited he incoming solar radiation. Areas under thick smoke, especially the Sierra Nevada are running more than 5 degrees cooler than forecasted.  The smoke will provide for hazy skies once again today across much of
our region.  Light winds will prevail until the ridge of high pressure weakens and shifts eastward, or by Thursday when a low pressure system begins to moves inland over the Pacific
Northwest.  This pattern change will usher in the first fall air of the season. Temperatures are expected to be 5 to 10 degrees cooler through the weekend.

Of concern to everyone, are the winds that are expected to develop Thursday into Friday. According to the NWS,  there appears to be two critical time frames for winds. They are expected to be during the afternoons primarily and last for some 3 to 6 hours each. The strongest winds according to the models are expected Friday with a bit more westerly direction.  They could gust upwards to  40 mph. Winds will diminish Friday night.

Of note, I have heard from reliable sources, that there is a large area of Granite between the fire and Mammoth Lakes. It is hoped that this area of granite acts as a barrier to help mitigate or slow down the effects of the fire.

Other Thoughts:

In speaking with a fireman earlier today, I has asked him questions like, how can one prevent flying embers from starting fires on my property.  Well,  he told me that we are all supposed to create a defensible space around our dwelling. If that has been done, then here are a couple of other thoughts.  If you burn with wood, and wood is stacked on a deck, there are fire resistant tarps that one can purchase and cover a wood pile with.  Also, be aware of vents coming out of a home. It is known that embers can fly into vents, and catch fire in an attic.

Dr Howard and the Dweebs………………….:-)

 

 

Zephyr Breezes to transport more smoke…..Troughing this week increases SW flow……Dry weather the next 7 days….

Once again smoke moved into our area from the SW with resulting poor air quality.  The advancing cloud of smoke from the Creek Fire, seen by many was the leading edge of a late afternoon zephyr that brought hazardous air quality to our immediate area. PM 10 counts were well over 600 parts per million.  The process is pretty straight forward.  The fire is burning some 18 to 19 miles to our SW.  The diurnal heating of the deserts provides for lower pressure to our east.  with higher pressure to the west, pressure gradient sets up drawing the smoky air into the greater Mammoth Area. Expect a repeat of the same today, so get your outdoor activities done early as the smoke will ride the Mono Zephyr into Mammoth once again, later this afternoon.

3 to 5 day outlook:

The upper high over Nevada will break down over the next few days allowing for an increase of SW flow through the pass. This will provide for both, a stronger Zephyr and one that is likely to begin earlier in the day.  The Breeziest days look to be this Tuesday and especially Thursday next week.  Needless to say, more critical fire weather conditions are expected next week. High temps will be in the low to mid 70s, cooling to the 60s by Thursday or Friday. Night time temps in the 30s and 40s next week.

Sunday PM Update

Thursday-Friday:
The National Weather Service did mention in their fire weather discussion AFD Today about the potential for a widespread critical condition event sometime during the Thursday/Friday timeframe of this week. That it was still early and things could change. The forecaster cited that the overall timing of the gusty southwest winds could change but for the most part it looks to be windy due to more upper-level support rather than just the thermal gradient of a typical zephyr.