Upcoming heat and lack of precipitation

Over the past 72 hours, nearly all of SD has gotten at least some precipitation. However, much of the north half of the state saw less than 0.15". But other areas of the state, namely the Rapid City area saw well over an inch. 

I hope you enjoyed it as today is virtually the last day we expect to see any precipitation across the state for some time. The WPC 7-day QPF is showing basically no precipitation and we can look out (maybe into la-la land) to 10 days with the GFS and it is saying the same thing giving up at some higher confidence in the forecast. 

The CPC is showing similar things in their 6-10 and 8-14 day outlooks. Just remember that these outlooks are showing anything except the probability of above or below average temperature and precipitation, not the strength of that anomaly. Recall that 20 degrees is above average and 1 degree is above average. But it still provides us with some useful intelligence that the beginning of August is likely to be warm and dry. 

We'll see what shakes out but I'm betting the fire potential will quickly be on the increase. And just in time of the Sturgis Rally. 

Critical Fire Weather Today

Today is a VERY interesting day from a fire weather perspective. There are a variety of issues that need to be discussed including: drought, prior precipitation, fuels, temperature, wind, RH, and thunderstorms (wind and lightning). 

Drought:

Drought conditions vary across the state but summertime wildfire activity is highly correlated to drought conditions. Here is the current USDM.

Prior precipitation:

Wildfire activity is also well-correlated to short-term precipitation deficits. Over the past 7 days, many areas have not received any precipitation across the state. Below is a map of the accumulated precipitation over the past week. 

Fuels:

The drought and lack of recent precipitation has led to a quick drying of the fuels on the landscape. Below you will see the current (as of 1300 MDT on 6/28) ERC chart for the region. 

From a "preconditioning" standpoint, all of the things are in place in order to get a large wildfire. The one thing holding us back in the lack of curing in the fuels. However, areas of central SD as well as those areas south of I-90 are seeing the herbaceous fuels undergoing a quick dry down and most areas will be receptive to ignitions and fire spread. It's not September dry but it is definitely drying down. 

Temperature:

If you haven't yet heard, it is going to be very hot today. High temperatures will be in the 90s and 100s in most areas. 

RH:

Along with those hot temperatures, the relative humidity will be critically low (note the color scale on the bottom). 

Wind:

Breezy southerly winds are expected over eastern SD and breezy southwesterly winds are expected over western SD through the day (see wind barbs in the RH figure above for wind direction). Winds gusts are shown below, again see the color scale at the bottom. 

Thunderstorms:

To add insult to injury, we are expected high-based thunderstorms this afternoon and evening which could result in scattered dry lightning. The images below show a weather model depiction of the radar reflectivity and associated with gusts today at 1800 MDT. 

Wind gusts from thunderstorms could range from 55-75 mph in an environment characterized by ~2000 J/kg of downdraft CAPE. That will not only be a threat to on-the-ground firefighting resources, but to aerial resources as well. 

It's an interesting day out there. Stay safe.

Current SD Fire Danger

We have an interesting situation across western and southern SD with respect to fuels and fuel greenness. Much of the state has been getting precipitation recently but there have been a few holes in the spatial coverage. Where these holes exist, the fuels are much drier and are currently receptive to ignition and fire spread. The South Dakota Grassland Fire Danger Map is not currently “seeing” these pockets of much drier fuels and is likely underreporting the actual fire danger. 

Below is a an image of the past 7-day precipitation totals. Look at where precipitation has and has not fallen to make a better assessment of where the fire danger may be enhanced. 

Interestingly, the area to the ESE of Rapid City has been notably dry and this is where the 90-acre Box Elder Creek wildfire occurred (photos below from Logan Scott, SDWF). You’ll notice a lack of green in the unburned herbaceous fuels and this is an area that hasn’t seen notable precipitation in at least 7-10 days. 

The regional ERC chart is also attached showing ERCs moving above the 70th percentile over many areas in the state. 

I’ve also gotten word from Brad Christensen, the EM Director for Gregory County, that conditions there are drying down rapidly and the Grassland Fire Danger maps do not appear to be reflective of observed conditions.

In short, make your assessments of fire danger locally with your own observed fuels conditions. There are most definitely places that could see rapid growth of wildfires.  

Hot temperatures are expected both today and tomorrow with very low RHs over southwestern SD. Luckily the wind shouldn’t be too strong during this same period. A cold front will bring showers and thunderstorms to the state Friday afternoon and evening with much cooler temperatures expected this weekend. 

Weekly weather discussion 11 April 2022

 

(Climate) We are working into the middle of April and we should be starting to see increases in precipitation across the state but it just isn’t quite working out that way. A few areas of the state did get some moisture this week and the biggest winners were generally on a line from southwestern to northeastern SD where a few tenths to over a half an inch fell. Spotty precipitation was also found over northwestern and southeastern SD but only a few hundredths to a tenth or two was recorded in those areas. Temperatures largely hovered around seasonal averages.

There was no change in the US Drought Monitor last week. (Darren Clabo)

 

(Weather)

Forecast Highlights:

A massive spring blizzard will impact the northern Great Plains this week but unfortunately the beneficial moisture from it will be mostly over ND leaving SD mostly dry but pretty breezy. Temperatures today will range from the 40s over northern SD to the low 60s over southern SD. Winds north of I-90 will be light and variable but south of the interstate, southerly winds with gusts to 25+ mph are possible. Minimum RH will range from 35% north to 15% south. A strong low pressure and cold front will race across the state tomorrow (this is the low associated with the blizzard expected over ND). This will lead to southeasterly winds in the morning becoming westerly to northwesterly by the afternoon. Gusts could exceed 55 mph over central and western SD. Temperatures will range greatly will the cold front: eastern SD will get into the 60s before the front passes while western SD likely won’t get out of the 30s and 40s. Look for temperature drops and winds shifting to the NW after frontal passage. Heavy snow will be possible over far northwestern and extreme northern SD while the rest of the state sees widely scattered rain/snow showers. Wednesday through Friday will bring breezy northwesterly winds with gusts to 35+ mph. Highs will be in the 20/30s over western SD and 30s/40s over eastern SD each day. A few snow showers will linger over northern SD on both Wednesday and Thursday. Temperatures will warm this weekend but how much they will warm remains a question: another low pressure looks to move through the state so we’ll have to monitor the changes due to this new system.    

 

Potential for critical conditions:

Critical fire weather conditions are in place over southcentral SD today. There is potential for more critical fire conditions over the southern half of the state tomorrow as the front pushes through. Be sure to look at your local forecast to determine your risk. Elevated fire danger is also possible on Sunday. (Darren Clabo)

 

(Fire/Fuels) The Wabash Springs Fire that occurred on April 7th burned 111 acres. The fire was driven by strong winds in an open pine stand. The grass burned very well but was checked up by any area that had been mowed previously and had some green component to it. No torching of trees was observed. Most of the Black Hills has seen a little moisture or will have potential for more in the next few days. With the cooler temps and chances of precipitation I do not foresee any fire issues this week. (John Haskvitz)

  

*** NOTE: Next update on Tuesday, April 19 ***

Weather weather discussion 21 March 2022

 

(Climate) It was another dry week across South Dakota, with drought continuing its grip on the state. Most of the state had no precipitation at all. Some far western areas received about one-tenth of an inch. In the north, from Mobridge to the Minnesota state line, there was one event that brought one-tenth to two-tenths of an inch of moisture, with as much as one-third inch in Roberts county.

Air temperatures were above average for the week. The southwest was about three to six degrees above average. Along the Missouri River, from north to south, was nine to fifteen degrees above average, and the northeast was six to twelve degrees above average.

The warm air temperatures and lack of snow cover has warmed soil temperature as well. As of this writing, the southwest quarter of the state is frost-free. The remaining locations still have frost, but soil temperatures through the profile are just below freezing and could thaw with a continuation of warmer-than-average air temperatures. (Laura Edwards)

 

(Weather) Forecast Highlights:

A dry and windy week is in store. Strong northwest winds (gusts from 30-50 mph) are expected under mostly clear skies today through Wednesday as a high pressure system drops in from Canada. High temperatures will be in the 40s and 50s each day while minimum RHs drop into the 15-30% range over most of the prairies, higher over the Black Hills and southeastern SD. Temperatures will warm into the 50s and 60s on Thursday while the minimum RH drops into the 15-30% range. Friday will bring highs back down in the 40s/50s with minimum RH from 25-45%. Both Thursday and Friday will remain breezy with northwesterly winds gusting from 25-45 mph, strongest over central and western SD.

There is some uncertainty regarding the forecast for the weekend, but it is looking warmer/drier once again. Highs will likely be back up into the 60s but the details on how far the warmth will spread are not yet clear. Precipitation will be hard to come by this week although a few rain/snow showers are possible over eastern SD later tonight and there is a slight chance of a shower over the Black Hills on Thursday.   

 

Potential for critical conditions:

Near critical fire weather conditions are expected today through Friday with the strong northwesterly winds in the forecast.  Minimum RHs will likely not dip to critical thresholds but they will be close. Any fire that does start will have potential to get large, especially over the prairies of western and central SD. (Darren Clabo)

 

(Fire/Fuels) Once again fuels remain uncovered (and cured) over most of the state, except for the higher elevations of the Black Hills and the far northeastern portion of South Dakota. The drought monitor hasn’t changed since last week. All western South Dakota is in a D1 drought with the northwestern portion of the state in D2. There is still the potential for piles to escape if there is wind present, but I foresee the potential going down day by day. With the warmer temperatures, there are areas that are starting to show the beginning of Spring green up.

 

Talking with the Burn Boss from the Antihorse RX that was conducted on Sunday, March 20th the burn went well. This burn was 15 miles west of Custer. He stated that they used a lot of head fire. The dead and down consumed very well. The grass didn’t burn very well in the morning but once temps came up and RHs came down it burned well. They struggled with the draws, any timber stands with a lot of shading, and north aspects due to moisture. (John Haskvitz)