Good Sunday evening,
We hope your Labor Day weekend is off to a great start. A lot of the region has been impacted by showers and thunderstorms today. That is due to a trough and strong backdoor cold front that will move through the Carolinas over the next 24 hours. The trough, as it slides east will usher a significant pattern change.
Monday is going to be a day of transition as winds begin to shift over to north-northeast and that will push less humid air into the Carolinas. Enough low level moisture will remain for Labor Day to spark off an isolated shower or storm but coverage overall will be less than it was today.
By Tuesday morning an extensive area of high pressure will be located over western New York and will continue to push in northeast winds making Tuesday a much cooler day (mid-upper 70’s) with temperatures running several degrees below normal for early September.
By Wednesday morning all the deep tropical moisture will relegated to the Gulf Coast Region. Here in North Carolina we will have a mix of sun and some clouds with temperatures running in the 70’s and lows in the 50’s…a pleasant start to the month of September!
Late week rain/CAD event looming?
Even though cooler temperatures are going nowhere this week, we may be dealing with an invasion of deep moisture by late in the work week. Currently the global guidance is strongly hinting at a cold air damming event for Friday across North Carolina.
Lets break down how it could evolve…
By Thursday an area of low pressure (non-tropical) in the Northwest Gulf of Mexico will push northeast into the Deep South located across northeast Louisiana by Thursday after with a pseudo-warm front positioned roughly along Interstate 20 (Shreveport LA to Birmingham AL to Macon GA). Here across North Carolina, surface winds will remain easterly. That along with southerly flow aloft will increase clouds again and that in itself will keep temperatures held in check.
Moisture will quickly increase by Thursday night across the Southern Appalachians and by Friday, low pressure will strengthen slowly and be located near Birmingham Alabama.
Meanwhile just off the surface, a developed upper low just to the north of the surface feature will help promote deep southerly flow from the Gulf of Mexico veering to a southeast upslope component by the time it reaches the North Carolina Foothills.
Looking at this from a forecasters point of view, this all sets off the bells and whistles for a significant rain event across the Interior Southeast on Friday. And with the cool, dry airmass in place, it strongly hints that the “Carolina Wedge” may lock in for Friday. Our forecast as of Sunday evening falls in line with this thinking.
Here’s the latest WPC precipitation forecast for this specific timeframe…
