The long awaited pattern change is about to commence. Cold front stalled to the west of Arkansas will slowly start to move east as the subtropical ridge finally shifts away and a trough deepens to our west. This will set the stage for an active Tuesday into Wednesday as showers and thunderstorms increase along the front. Shear profiles and instability levels look decent but not overly impressive. However they are high enough that strong to severe thunderstorms will be possible, mainly over the western half of the state. All modes are possible, but damaging winds will be the primary threat along a squall line as it moves across overnight tuesday night and Wednesday Morning. The front will be moving at a steady pace, so any flash flooding should remain isolated in nature. Most likely areas to see it will be the western 2 rows of counties where the front will be the slowest. Behind the front, our fall airmass awaits. Skies will clear from west to east Wednesday afternoon and evening as high pressure settles into the region. We will see highs drop to the 60s and 70s with lows in the 40s and 50s. End of the period will be dry as high pressure remains in control.
This period can be described as highly amplified. Hurricane Michael quickly moving through the southeast U.S as it phases or moves just east of the trough. Locally though we will see good cold air advection sending temps and dew points well below seasonal norms under mostly sunny skies. Pattern will reload on Saturday as another trough and associated cold front starts to head this way. Moisture will increase ahead of it but will not increase too much due to limited time for recovery. A surface feature will break off of the flow and close off, becoming a closed low. This will quickly move into the southern plains, bring in another cold front through the state. With moisture return limited, things should stay below severe limits. There will be enough moisture though to provide a chance of scattered showers and possibly a thunderstorm on Sunday. Behind the front, even colder air will advect into the state with 50s and 60s for highs and 40s for lows. There is some data that wants to bring us into the 30s for lows, as well as a frost or freeze to parts of the state by Tuesday night. I don't buy this YET, but this will be watched closely. Regardless, Fall looks to be here to stay.