It has been a pretty active couple of days in AB in terms of severe weather and is expected to be once again today and even into tomorrow possibly, but will focus on today. The reason for this severe weather in recent days is all due to large upper low that has been almost stationary off the west coast of WA and BC. This analysing the current water vapor image can see that this upper low now centered over the WA/OR border is pushing inland. At the base of this upper low is a strong shortwave trough which is pushing through northern NV, this shortwave is forecast to push into MT late this afternoon and evening which will aid with overall large scale ascent within the warm sector of the low. Associated with this upper low is a strong jet core at 500 mb out of the south southeast (see 2^nd image) which will move along and parallel to the Rockies which will also produce mesoscale regions of enhanced vorticity and lift which will also bring the BC interior and AB foothills into play today (as indicated in the 3^rd image). Furthermore 500 mb analysis of this afternoon also shows region of strong difluence located over the southern portion of AB.

At the surface is a rather complex situation this morning, image below indicates where morning front positions are with the warm that that has stalled some in eastern AB but radar this morning does indicate the presence of an outflow boundary that is slow pushing northward which should stall some point today near or just south of Calgary to around Oyen and there is current indication that the convection ongoing near Swift Current may be putting out an outflow boundary as well. These two boundaries could serve as initiation points later this afternoon, or could act to enhance the storm environment with added low level shear; this would depend on whether they mix out also.

  By this afternoon the warm front will push into southern AB with stationary front through the BC interior and a dryline extending through the U.S. where it intersects a cold front in MT. There are two area outlined on the map below the purple indicated where I believe there is the risk of some storms today possibly severe. The pink area indicates where I believe there is likely hood of severe storms with the risk of isolated tornadoes. Within the warm sector SBCAPE values are forecast to reach the 2000-3000 J/kg range which is agreed upon by the NAM/GEM, as well as the RAP/HRRR to an extent. With the southeast flow near the surface I suspect some drying out will take place to the southeast of the Medicine Hat area due to some down sloping form the Cypress Hills, these CAPES near here will decrease quite a bit due to the drying out. Along with the instability is sfc-500 mb bulk shear values in the 40-50 kts range with 25-30 kts in the sfc-850 mb layer with largely veered hodographs within the lowest 1-1.5 km. All parameters considered this leads me to believe that there will strong storms, with supercell structures within the pink outlined area. Expect storm to initiate along the foothills in AB and interior BC and in MT this afternoon with later initiation within the area outlined by Medicine Hate, Letbridge, and Brooks, where I believe most dangerous storms will be. Storms along AB foothills will likely follow a slightly east of north track following the 500 mb flow. As the 850 mb winds increas fromt the due east and northeast sfc winds expect strongly rotation storms to develop here, this also puts Calgary within an isolated tornado risk for this afternoon as well. There is some indication that the warm front in SK will light off this evening as the 850 low level jet strengthens. As storms progress NNE will likely congeal into massive line/MCS where some spinups are possible along or in the vicinity of the warm front. NOTE: Will have to monitor any outflow boundaries as mentioned above through today for additional initiation in the warm sector in SW SK and AB, or enhancement of storm environment.