TROPICS UPDATE: WEDNESDAY, OCTOBER 9, 2019
A LARGE NOR’EASTER-LIKE STORM IS DEVELOPING OFF THE MID-ATLANTIC COAST. IT WILL ABSORB THE TROPICAL DISTURBANCE THAT HAS BEEN DRAGGING TROPICAL MOISTURE OVER SOUTH FLORIDA, BUT THE MOISTURE FEED WILL CONTINUE INTO TOMORROW.
A northern cold front and its associated upper-level dip in the jet stream has developed a large nor’easter-type storm off the Mid-Atlantic coast. That’s typical weather stuff, but the wrinkle comes in the form of that tropical disturbance that dumped all the rain on South Florida, which is continuing to pull tropical moisture north.
The disturbance is forecast to be absorbed by the nor’easter by tomorrow, giving it only today to exist on its own. The National Hurricane Center has given it a modest chance of organizing into a tropical storm today before its window closes. Whatever happens to the disturbance, it won’t affect the weather in Florida.
Tropical moisture being pulled north into the disturbance will continue to control the weather in South Florida into tomorrow. Finally, the big northeastern storm will dominate the circulation, and it will push drier air south through the state. Tomorrow is the transition day.
The nor’easter-type storm is forecast to get fairly strong and meander off the Mid-Atlantic coast for a couple of days. If it drifts over warm enough water, there’s a slight chance it could take on some tropical characteristics, meaning it would start getting some of the its energy from the warm ocean. If the National Hurricane Center determines it is sufficiently tropical, they would name it a subtropical storm.
If that happens, it won’t change the effects on the Mid-Atlantic and Northeast coast – gusty winds, rough ocean, high tides, and heavy rain.
And a separate winter-type low-pressure system is spinning in the middle of the Atlantic. It too has the slight chance of becoming sufficiently tropical to get a name. Oddly, it is also forecast to eventually get at least partially wrapped up in the big nor’easter and get killed off. The remnants could affect Atlantic Canada if it slingshots around the bigger storm.
In the tropics, we’ll watch the southwestern Caribbean, where storms often form in October. Some computer forecast models show development of one sort or the other near Central America next week, but not in a consistent way, and nothing shows a threat to the U.S.