Why are funnel clouds expected in Saskatchewan today?


SLP, pressure and associated fronts as of 1:00pm CDT

Why are funnels expected in Saskatchewan anyways? It's because of this Low pressure seen in the picture above. This surface low pressure causes surface convergence and upward motion in the atmosphere.



The picture below is a graphical depiction of this:

Depiction of surface Low pressure and divergence aloft

This will trigger pop-up thunderstorms in the province this afternoon. Now why the funnel clouds? Well this is related to the vorticity associated with this Low pressure.




Cold air funnels form beneath showers or weak thunderstorms when the air aloft is especially cold.  The funnels are most common in the fall and spring when the sun is able to heat up the lower levels of the atmosphere, causing convection to bubble up and form showers, but temperatures around 15,000 to 20,000 feet above the ground are quite cold.  Cold air funnels are usually harmless, but on rare occasions they can touch down and cause EF-0 level (winds up to 85 mph) tornado damage. -National Weather Service

Below is a clear depiction of where the Low is and its associated vorticity:

Vorticity associated with Low pressure in Saskatchewan at 1:00pm CDT

Vorticity can be seen to occur around this Low pressure, this combined with rapid upward motion in developing thunderstorms can cause funnel clouds and sometimes landspout tornadoes to develop in the vicinity of the Low pressure. Days like today in Saskatchewan are ideal for funnel clouds and landspouts. This is why Environment Canada has special weather statements out:

Statements

10:33 AM CST Saturday 22 June 2019 Weather advisory in effect for areas in grey:


Conditions will be favourable for the development of funnel clouds today. These types of funnel clouds are generated by weak rotation under rapidly growing clouds or weak thunderstorms. This weak rotation is normally not a danger near the ground. However, there is a chance that this rotation could intensify and become a weak landspout tornado. Landspout tornadoes do not usually cause significant damage but can still be dangerous. They can be strong enough to topple trees, damage roofs or toss debris short distances. Treat any funnel cloud sighting seriously. Should a funnel cloud develop nearby, prepare to take shelter. These funnel clouds usually appear with little or no warning.

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