Taste Of Fall–Plus, Tropical Troubles Off The Southeast Coast?

If you’re tired of the heat and ready for a taste of fall, you’re in luck. Numerical guidance has been fairly consistent in suggesting a pattern change that will lead to a nice cool down for much of the central and eastern United States for the end of August into the first week of September.

Numerical guidance is suggesting an amplified trough will dig into the central U.S. & begin to deepen next week as it moves east. This will act to send a strong cold front south into the Southern Plains by late next week, followed by a slow push into the South & Southeast by late next weekend into the following week.

The Climate Prediction Center concurs and suggests days 8-14 (August 29th through September 4th) have a high probability to see below average temperatures for much of the central & eastern United States (see Fig. 1). It should be noted, there are some significant disagreements on the fine details of the setup, but overall, all guidance is suggesting a cool down will occur.

Fig. 1: CPC Temperature Outlook Days 8-14

What will the temperatures look like for the South & Southeast? It appears highs will fall into the low to mid-80s with overnight lows in the upper 50s & 60s. But hey, that’s way better than 90s & 100s! Here is a look at the temperature trends for several cities in the South & Southeast through 16 days (please note these values are likely to change significantly over the next several days–it is possible the highs/lows will decrease further towards the beginning of September):

Fig 2: Atlanta, GA Temps

Fig 3: Birmingham, AL Temps

Fig. 4: Columbia, SC Temps

Fig. 5: Jackson, MS Temps

Fig. 6: Nashville, TN Temps

Fig. 7: Shreveport, LA Temps

Fig. 8: Dallas, TX Temps

Fig. 9: Oklahoma City, OK Temps

Fig. 10: Litte Rock, AR Temps

Firsthand Weather is also keeping an eye on a tropical disturbance over the Bahamas. This disturbance has become better organized over the past 24 hours thanks to the low wind shear (see Fig. 11). A northwest movement toward the east coast of Florida is likely over the next 24-48 hours, followed by a northerly then northeasterly movement just off of the Southeast Coast through the weekend into early next week.

Fig. 11: University of Wisconsin Wind Shear Map

The disturbance will move into continued favorable environmental conditions which may allow for a tropical cyclone (tropical depression or tropical storm) to develop over the weekend. The National Hurricane Center has upped the chances for development to 30% over the next five days (see Fig. 12). The EPS is on board with development into a tropical depression over the next 24-72 hours with probabilities greater than 70% (see Fig. 13).

Fig. 12: NHC Five Day Tropical Weather Outlook

Fig. 13: EPS Tropical Depression Probability

Numerical guidance indicates this system will stay just off of the Southeast Coast (Georgia, South Carolina & North Carolina) from early week into mid-week as the system moves northeast. Increased rain & rough seas are likely for Florida over the weekend and possible enhanced moisture and rough seas for coastal areas of the Carolinas early week through mid-week. If this system develops into a tropical cyclone, it will be named Dorian. Please note, there is still some uncertainty with the evolution and track of this system so keep checking back for updates.