Good morning everyone and happy Wednesday! After several rainy days we are continuing to track more rain and potential flooding concerns for the next couple of days. With a weak upper-level low just off the Gulf Coast combined with the continuous onshore flow piling up moisture and allowing for heavy rain bands to form.
If we take a look at the current synoptic picture of the region, we can pick out these features in more detail.
Looking at the upper-level pattern, we can pick out a ridge over the Atlantic extending into our region, along with a low just off of the Gulf Coast. While this low isn’t expected to form into any significant tropical system, any extra “push” of moisture is enough to trigger showers and thunderstorms that can drop a significant amount of rain in a short period of time. Storms will also likely be slow to move, thanks to upper-level steering flow being weak at only around 20kts, which is why flooding is the main concern from these storms.
And there is plenty of moisture which is no surprise, with precipitable water values over 2″ throughout the area.
Thanks to these all these features working together, temperatures are likely to reach their peak early, before cooling off in the afternoon from thunderstorm activity. High temperatures across the area for today are expected to reach the mid to upper 80s along the coastline prior to the cool down.
Due to the chance for excessive rainfall, the WPC does have portions of the Louisiana coastline under a slight risk for excessive rainfall, with areas of coastal Mississippi under a marginal risk.
For these reasons, it is important to monitor your local NWS office for any flooding related advisories and warnings, as these storms can drop a significant amount of rain in under an hour. A coastal flood advisory also remains in effect until Thursday thanks to the more persistent onshore flow from the low pressure system.
By the time we reach Friday, the WPC is forecasting up to 2″ along coastal areas of Mississippi, Louisiana, and Alabama, with isolated higher totals.
If we start to glance into the pattern for the weekend and early next week, our region receives a pattern shift as a deep long-wave trough moves across the northeast and the ridge to our west continues to build and move closer to our area.
As we can make out from the graphic, ridging will be present near Colorado and Kansas, with the ridge axis extending into northern Louisiana. In addition, the long wave trough is denoted by the red “L” over New England.
For our area, this northerly flow will usher in a much drier mid-level airmass as we can see on an averaged sounding of the coastal area.
At the surface, this shifts our main area of concern from thunderstorms to wind rather than heavy rain, as the layer or dry allows for evaporative cooling which makes the air denser allowing it to accelerate faster towards the ground. In addition, this pattern with the ridge to our west and upper-level northerly flow will lead to temperatures being right around average for the coming week!
Day-to-Day Forecast
Today
Mostly cloudy with a 70-percent chance of showers and thunderstorms. Flooding possible especially in poor drainage areas. Highs in the upper 80s with wind southeast at 5-to-10mph.
Tonight
Mostly cloudy with a 40-percent chance of showers and thunderstorms. Lows in the mid 70s with a south wind at 5mph.
Thursday
Mostly cloudy with a 60-percent chance of showers and thunderstorms. Highs in the upper 80s with a southeast wind at 5-to-10mph.
Thursday Night
Partly cloudy with a 30-percent chance of a shower or thunderstorm. Lows in the mid 70s. Wind calm.
Friday
Partly cloudy with a 50-percent chance of showers and thunderstorms. Highs in the upper 80s. Wind southeast at 5mph.
Friday Night
Partly cloudy with lows in the low-to-mid 70s. Wind calm.
Saturday
Mostly sunny with a 50-percent chance of showers and thunderstorms. Highs in the upper 80s with wind southwest at 5-to-10mph.
Saturday Night
Partly cloudy with a 30-percent chance of showers and thunderstorms late. Lows in the low-to-mid 70s. Wind calm.
Sunday
Mostly sunny with a 40-percent chance of showers and thunderstorms. Highs in the upper 80s to around 90. Wind southeast at 5-to-10mph.
Sunday Night
Mostly clear with lows in the mid 70s.
Monday
Mostly sunny with a 30-percent chance of showers and thunderstorms. Highs in the upper 80s.
Monday Night
Mostly clear with lows in the mid 70s.
Tuesday
Partly cloudy with a 30-percent chance of showers and thunderstorms. Highs in the upper 80s.
Tuesday Night
Mostly clear with lows in the mid 70s.
