The Atlantic tropics have become quiet again. The tropical depression we were watching in the Gulf became Tropical Storm Bertha, but it skirted the Gulf Coast, and what remains of it is in Texas and Mexico today.
The above loop of visible satellite imagery above shows several features of interest across the North Atlantic and eastern U. S.:
- A band of clouds associated with a front over the western Atlantic, the Carolinas, and westward into the Plains states.
- Tropical waves along 63° west in the Caribbean, along 45° west over the central tropical Atlantic, and near 27° west over the eastern tropical Atlantic.
- Clouds over Texas and Mexico associated with the remnants of Tropical Storm Bertha.
The only effect Bertha had on us was to bring an influx of tropical moisture that will contribute to the risk of heavy rainfall and flash flooding in parts of our state through Saturday. More on that below.
Elsewhere in the Atlantic, there are three tropical waves to track, and a fourth that will emerge from Africa soon. However, it's unlikely that any of them will develop further over the next week. Hostile conditions are present all over the Main Development Region of the Atlantic (the area between 10° north and 20° north), with either strong vertical wind shear due to strong westerly winds aloft or a dry, stable atmosphere -- over much of the region, a combination of both.
We have a stationary front over us and to our east and northeast over the Atlantic, which is always something to watch for sneaky developments this time of year, but we don't see any indication from our computer models that this will happen.
Stay prepped; hurricane.sc is the place to go for prep advice.
Flash Flooding Risk Through Saturday
Finally, a front has moved in to bring a break from the heat. With it comes the potential for a soaking rain that we badly want and need. However, we're at risk of seeing a 'too much, too fast' situation with the rain through Saturday that could lead to flash flooding.
Three factors are in play. First, we have a stationary front over our state that is one of the triggers for showers and thunderstorms. Second, we have a series of upper-level disturbances that will move through and trigger at least a couple of waves of heavy rainfall through Saturday. Third, ample moisture is present, and we can partly thank Bertha for steering moisture into the Southeast from the tropics.
So, we're likely to see rain and embedded thunderstorms through Saturday, with tropical downpours. The risk for flash flooding through the rest of today and tonight is greatest over the Coastal Plain and the southern Midlands, which the Weather Prediction Center (WPC) has outlined in a level 3 of 4 'moderate risk' area for excessive rainfall.
Risk level 3 for these outlooks is where it gets serious. To put it in perspective, 17 percent of all US flood-related fatalities and 4 percent of flood-related damage from 2010 to 2020 occurred in one of WPC's moderate risk areas.
Where it gets hot again this afternoon along the Coastal Plain, an isolated severe storm with damaging winds is also a threat.
The excessive rain concern continues for Saturday, though the risk level will be lower. The rain and thunderstorms will likely diminish Saturday evening.
Of course, the potential for heavy rain will hold temperatures down through Saturday; we'll see upper 70s north to mid-90s south this afternoon, then low 80s north to around 90° south on Saturday.
Sunday looks less active, but we're likely to see a typical scattering of afternoon and evening thunderstorms. Highs will mostly be 88-92° across the state, making it a decent midsummer day.
On Monday and Tuesday, we trend back to more heat and fewer afternoon thunderstorms. Actually, we'll see few storms, if any, on Tuesday. By Tuesday, highs over most of the state will be back in the mid to upper 90s again with the heat index peaking well over 100. Ugh.
The computer models agree that another front will move in Tuesday night or Wednesday, but differ on timing. They also show the front pushing through with somewhat cooler and less humid air moving in behind it for the end of the week. The models threw that pitch at us last week, and (as I feared), the pitch was juuuust a bit outside. So, I'm skeptical about what the models are showing later next week. Typical summertime heat and scattered afternoon thunderstorms as the front stalls and washes out over us seem likely to me.