A weather system meteorologists are calling an “atmospheric river” is bringing massive amounts of rain and snow to California.
As a high pressure system over the west coast moves out of the way, massive amounts of precipitation are being funneled into California and Oregon. As orographic lifting squeezes the moisture out of the air mass some areas in the Sierras could receive up to two feet (24 inches!) of precipitation before this event is over. If most of it falls as snow in the mountains, the peaks in the Sierras could see up to 10 feet of snow.
It has already started, as you can see in the graphic below showing the snow received as of Wednesday morning. And the storm has just begun.
It remains to be seen how this will affect California’s five-year drought and the 2017 fire season. In 2016 the northern part of the state saw some relief from the drought, but there was not much change farther south.
Above: The chance of above median maximum temperature in Australia, December through February.
The Australian Bureau of Meteorology is predicting that the eastern half of their country will experience a summer that is warmer and dryer than normal. That season is just beginning; their highest temperatures usually occur in January and February, but Tuesday produced the hottest December day in Sydney in the last 11 years, hitting 39.2C (102.5F) at Sydney Airport.
Below is an excerpt from an article at Australia’s ABC News about how Tuesday’s weather could affect wildfires:
Fire danger warnings are in place across a large part of Australia, with hot temperatures and windy weather expected, the Bureau of Meteorology (BOM) says. Fire authorities are on alert in the south-eastern states, with total fire bans in place in regions of South Australia, New South Wales and Victoria, and a high danger in Tasmania.
Temperatures were forecast to reach the mid-30s in the southern states, with a maximum of 36C in Sydney and Adelaide, 34C in Melbourne and 33C in Canberra.
In Darwin, the maximum expected temperature was 34C, 29C in Hobart. Perth’s forecast top was a cooler 26C and Brisbane 29C.
High temperatures in several capital cities at the same time is “a bit different”, senior BOM meteorologist Claire Yeo said.
“Those hot temperatures ahead of that wind change [are] increasing the fire dangers into that very, very high to severe range,” Ms Yeo said
“But there is also an added impact that we don’t necessarily or aren’t necessarily able to reflect in the fire danger rating, and that’s the way the atmosphere behaves in these kinds of conditions.
“Today is a classic example where if a fire was to start in your particular area, the atmosphere is primed for [it]. If a smoke plume develops over that fire, it can get to quite an extensive height … and we see very erratic fire conditions and fire behaviour in that kind of atmospheric condition.”
Ms Yeo said more frequent fire danger ratings were expected in coming days.
.@NSWRFS Very Large Air Tanker assists over the Oaklands fire ground this afternoon. Fire under control at 4000ha. Pic:Splitters Creek RFB. pic.twitter.com/xh56aIEiMW
On December 1 the Predictive Services section at the National Interagency Fire Center issued their Wildland Fire Potential Outlook for December through March. The data represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.
If their predictions are correct, the elevated wildfire danger that has plagued the southern states for weeks will be returning to normal. From January through March their analysis shows no areas with above normal wildfire potential.
Above: Snow cover in the United States, November 18, 2016. The Weather Channel.
Precipitation in the northwest quarter of the United States this week has put even more of a damper on the occurrence of wildfires, the execution of prescribed fires, and agricultural burning.
After weeks of warm, dry weather the Black Hills finally received a little precipitation over the last 24 hours. I won’t know the exact amount at my house until the snow in the rain gauge melts, but there was an inch or two of the white stuff on the ground. Today is sunny with a high of 32 predicted, so maybe it will trickle through the tipping bucket this afternoon.
Small amounts of precipitation in southern Saskatchewan may be the reason smoke from that area is no longer immigrating into the United States, as you can see in the two maps below. The first one was the smoke forecast for November 15 and the one after that is for today, November 18.
However, prescribed fires, wildfires, or agricultural burning in Louisiana, Arkansas, and eastern Texas are still producing large quantities of smoke that at times moves north into the midwest.
On November 1 the Predictive Services section at the National Interagency Fire Center issued their Wildland Fire Potential Outlook for November through February. The data represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.
If their predictions are correct, firefighters in the southeast and in southern California could see significant wildfire activity in November and December.
Scroll down to see additional wildfire potential maps, the drought monitor, and the 90-day temperature and precipitation outlooks, but immediately below are highlights from the wildfire potential outlook.
November significant wildland fire potential is generally very minimal throughout the northern tier of the U.S. as conditions transition out of normal fire season. Areas of the Great Basin and Rocky Mountains that are currently seeing increased levels of fire activity are likely to see much of that activity diminish and transition to out of season conditions through early November.
Exceptions will continue in Southern California where long term drought is still in place. Conditions in this area will slowly transition to normal from north to south through the Outlook period. Normal implies a significant reduction in fire activity, but some fires should still be expected. Also, the southeastern U.S. will continue to see a large area of above normal significant fire potential for November and December that will slowly transition back to normal through the Outlook period as well. This condition is also largely due to long term drought that is going to be exacerbated by dry leaf litter falling on top of already dry fuels and also occasional dry and windy periods. For the southern Plains there is a plentiful grass crop that presents the potential for occasional dry and windy periods to increase fire activity.
Normal winter conditions will prevail across the U.S. in January and February. There will be occasional periods of increased fire activity, but these will be infrequent and difficult to predict accurately. During this outlook period winter precipitation and snowpack development will be a critical situation to monitor as the 2017 fire season becomes the focus of many fire managers.
Rainfall over the last two weeks has slowed or in some cases, ended the wildfire season in some areas.
On October 19 we ran the numbers for the accumulated precipitation for the last 14 days in the western states. These maps show amounts that exceeded 0.05 inches at some of the Interagency Remote Automatic Weather Stations (RAWS).
Washington, Oregon, and northern California have received a good soaking and I would imagine that local fire officials may be declaring an end to the fire season. Of course this is not unusual for these areas this time of the year, and some locations had already seen their season end. But what IS unusual, is the high amount of moisture that occurred in just two weeks.
You can click on the images to see larger versions.