Tag: storm chase

Storm Chase Log – July 9th to 10th

Matthieu Leave a comment

As Brad forecasted on his Friday post, severe storms were expected on Saturday across southwest Manitoba as a result of an upper level ridge that rounded the southern Canadian Prairies began breaking down. Scott and I decided on Friday night to head out from Winnipeg for a chase around noon on Saturday in expectation of the severe storms.

July 9th

We decided, as our general target area, to head south of Brandon and refine the area as the early afternoon wore on because elevated convection was ongoing in the region. As we headed down highway 2, conditions looked promising for surface based storms as there wasn’t much cloud cover near border regions.

Initially we kept an eye on bubbling cumulus near Melita as we blasted west, however as we approached the so thought “elevated storms” near Souris it was evident that the storm had become surface based. Clear skies and warm temperatures south of the storm allowed the storm to ingest surface parcels as it dived southeastward. As we initially got close to the storm, we saw that the storm had a ground scraping shelf cloud – some of the best storm structure observed in southern Manitoba this year was observed west of Ninette. We continued to follow the storm in a southeasterly fashion and rotating wall clouds formed on a few occasions near Minto and Dunrea. It was also evident that the storm was producing damaging hail as the core had a greenish tinge of color.

Ground-scraping shelf cloud as we initially approached the storm north of Ninette.
Ground-scraping shelf cloud as we initially approached the storm north of Ninette.

Ongoing storms south of the border near Devils Lake spat out rain-cooled air and the supercell storm eventually began dying off near Cartright. Regardless, we continued to follow it south of the border until it eventually gusted out by late afternoon. We then looked at the weather models and saw that the next day could once again produce strong storms, this time in western North Dakota so we headed to Minot for the night.

A few rotating wall clouds were observed as the supercell dove southeasterly, northwest of Killarney.
A few rotating wall clouds were observed as the supercell dove southeasterly, northwest of Killarney.

July 10th

On the morning of the 10th we did our analysis and looked at short term convective models only to find that there was much disagreement as to what would happen during the afternoon. Most models did convect strong storms in the Dickinson area so we headed in that direction, from Minot. Unfortunately we forgot to check for construction delays before leaving and picked a highway that had construction for over 30 km. After a scenic route through the badlands of western North Dakota, we approached our target area. Simultaneously, storms began to form to our southwest near Baker, Montana – great timing!

We passed through Killdeer, North Dakota and headed to Dickinson to orient ourselves south of the storm. By then the storm was a full-fledged supercell. Once again it was evident that the storm was chucking very large hail. Green skies were present and the radar depicted reflectivities of over 70 dBz, we had to make sure not to get caught in the core of the storm. We first took a peek at the storm just northwest of Dickinson – this is when the storm looked best. A rotating wall cloud was observed and the storm appeared to be close to producing a tornado. Only about a half-hour or so after the wall cloud was initially observed however, the rear flank downdraft (RFD) of the storm had a mighty surge, near Killdeer. The RFD undercut the updraft portion of the storm and formed a shelf cloud – it was then evident that the storm had little tornado threat so we abandoned it. It did however have a significant wind and hail threat – Killdeer took the brunt of the storm and significant damage was observed to cars and houses.

Picture taken right after the hailstorm in Killdeer shows the extensive damage that wind-driven baseball sized hail causes. Windshields of cars were blown out as well as windows and siding destroyed in Killdeer. (Source: Ohio Storm Chasers//Aaron Rigsby)
Picture taken right after the hailstorm in Killdeer shows the extensive damage that wind-driven baseball sized hail causes. Windshields of cars were blown out as well as windows and siding destroyed in Killdeer. (Source: Ohio Storm Chasers//Aaron Rigsby)

We then bailed south to a secondary cell that had formed in extreme southwest ND. Lift along the front was too strong for any significant tornado potential and storm became linear. A bow echo was taking shape. We were, however, treated to an exceptional light show on the way back to Bismarck and 90km/h winds with torrential rains as were experienced as we cored the bow echo.

A bow echo raced across central ND as storms consolidated into a line by late evening.
A bow echo raced across central ND as storms consolidated into a line by late evening.

(Un)fortunately the tornado potential did not pan out for our two day chase trip, but overall some great storm structure and lightning was observed!

Elsewhere in Weather News: July 26th, 2014

Matthieu Leave a comment

Saskatchewan Chase July 24th

An unusually strong upper level low for this time of the year nosed into the southern Prairies and was the focus for severe storms last Thursday. All the ingredients were present for severe storms that day, as Brad alluded to in his discussion of the event posted on the day of. Keeping in mind that this might be one of the last chases this season, due to the jet stream slacking up, a few of us made our way into Saskatchewan to chase the storms.

The day was off to somewhat of a surprising start as we woke up early to find a large squall line was sweeping across southeast Saskatchewan, southwest Manitoba and North Dakota. Thankfully, as the squall line moved away from the main instability axis in the morning it started weakening and its leftover cloud wouldn’t hamper our chances in Saskatchewan for the surface based storm development in the afternoon. After determining that skies would clear in the south-central part of Saskatchewan by late morning, the chase was on. From Winnipeg we drove straight to Brandon, grabbed a quick bite to eat and from there made our way to Weyburn, SK. After arriving in the mid-afternoon, we took a quick look at the satellite only to see some bubbling cumulus and even towering cumulus well to our southwest. By then it was obvious that nothing would fire in the Weyburn area with a stout cap present and no trigger around.

We then had to make a decision to either call it a day or head to south-central SK – where there was plenty of upper forcing and a cold front in the region (further west than what the models were showing). Since we were already that far into SK, we went all in and drove a good 100km west to the Assiniboia region. By the time we got there a couple supercells had already fired; we picked the one that looked best (just south of Assiniboia) and stuck to it.

Picture of the storm as it matured, looking towards a section that was bowing out, with a good shelf cloud. (Source: Matt)
Picture of the storm as it matured, looking towards a section that was bowing out, with a well-defined shelf cloud. (Source: Matt)

Following it for over two hours, we were able to spot two funnel clouds. One may have touched the ground, but we were too far away to tell (hence lack of pictures) while the other a brief funnel that spun up later in the evening on the leading edge of a bow echo. We followed the storm which evolved into a line with multiple bow echos embedded along it. Later in the evening the line became elevated, eliminating the wind threat but still able to produce a lot of cloud to ground lightning. The complex eventually died off in southwest Manitoba and left a large area of stratiform rain in the area.

Overall it turned out to be a fun chase day, with a storm that teased us with a few funnel clouds, combined with good structure and a nice light show. What we didn’t see from that day were the large hailstones that were later reported as well as strong wind gusts of 119km/h reported in Assiniboia.

Elsewhere in Weather News: June 21st, 2014

Matthieu Leave a comment

South Dakota Wessington Springs Tornado – June 18th, 2014

Three members of A Weather Moment team headed out to South Dakota this past Wednesday to chase severe storms and try to catch a tornado. It turned out to be quite the event. Julien has written a summary of what how the chase unfolded.

We left Winnipeg bright and early at 7 am on Wednesday and headed south. Our plan for the day was to target the warm front/triple point in southeastern South Dakota. We reached Fargo by late morning. After getting our internet worked out and had lunch, we continued south to Sioux Falls, South Dakota to reassess things (by then it was mid/late afternoon). We decided to head west a bit to Mitchell first, then Plankinton, SD. It was oppressively humid with dewpoints in the low to mid 20’s and temperatures near 30°C. In fact, as I walked out of the car, my glasses were fogging up! These yielded MLCAPE values around 5,500J/kg resulting in an explosive environment for any storm that formed.

By then, storms to our northwest were strengthening rapidly and rotation became evident on radar imagery. A tornado was also reported by another storms chaser. We were concerned of the possibility that additional storms would fire off south of the existing ones and become dominant. As a result, we decided to wait a little longer. Nothing new was really forming due to a strong cap, so we decided to head west then north of Kimball, SD to view the existing storms. We were impressed! Towers were shooting up extremely rapidly and there was decent structure to the storm. Rotation could be seen in some parts of the storm.

Not too long later, we repositioned north of Plankinton, SD, which was eastward. As we got closer to the storm, two funnels poked out of the trees! It was evident that the one in the distance was a tornado. However, the second funnel was hard to say if it was touching down or not because it was not condensed all the way to the ground. However, it’s impressive seeing 2 funnels simultaneously!

One funnel and a tornado simultaneously, with the one on the left touching down. (Taken by Matt)
One funnel and a tornado simultaneously, with the one on the left touching down. (Taken by Matt)

We followed the storm eastward and the dominant tornado was not giving up! Even though we were well in the distance far away from the tornado, we could clearly see its circulating winds moving rapidly which was quite impressive. Unfortunately, we did occasionally see debris being picked up. It took several minutes for the tornado to finally rope out and lift… before we witnessed it strengthening and enlarging again briefly. Then it dissipated and that was it for tornadoes for us for the day. After our chase was finished, we had heard that there was serious damage to the town of Wessington Springs, SD however no serious injuries had been reported thankfully.

Stovepipe tornado we observed. (Taken by Matt)
Stovepipe tornado we observed. (Taken by Matt)

We slowly made our way east to Brookings, SD for the night at a hotel. We left back for Winnipeg Thursday morning before 11 am and reached Winnipeg by around 6 pm or so after stopping by at Longhorns restaurant for a well-deserved tornado steak dinner in Fargo. The next day NWS had done a damage survey of the tornado and rated it an EF-2 tornado, the strongest tornado we had ever witnessed. Overall, it was well worth the trip!

This trough not only produced tornadoes on Wednesday in South Dakota, but also on Monday and Tuesday in Nebraska, including the incredible supercell near Pilger, NE that produced two large wedge tornadoes simultaneously. The upcoming pattern definitely looks calmer with upper flow slacking up in the US Plains; possibly hinting that summer is right around the corner for the region.