September 26, 2020

Look out. There could be more rain to come. Hurricane Centre watching Caribbean low as more rain moves in


Pin It

Our three days of rain has got the attention of the the National Hurricane Centre, where forecasters began tracking Invest 94L. Analysis on Wednesday (23) morning of 850 millibar and 700 millibar vorticity values (the amount of spin in the atmosphere) revealed an elongated area of vorticity stretching from the Florida Straits southwestward across much of the western Caribbean. Shear values across the western Caribbean ranged from 20 knots near the northern coast of Honduras to 40 to 60 knots near the southern coast of Cuba.

Rob Lightbown of Crown Weather had this to say about the system:

“As it stands right now, Invest 94-L is in an area that is not favourable for development. Much of the convection is located to the east of the low pressure system, wind shear values are quite hostile and it is still attached to a trough of low pressure and has not isolated itself.

“The short range NAM model forecasts that this low pressure system will lift out of the Caribbean and into the Gulf of Mexico during Thursday and redevelop along the South Carolina coast by later Friday. A bout of heavy rainfall, associated with this low pressure system is first expected across the Florida Keys starting this afternoon and spreading northward into south Florida during Thursday. This heavy rainfall is expected to continue across south Florida and the Florida Keys into Thursday evening before ending later Thursday night.

“The GFS model guidance does nothing with Invest 94L, however, it does forecast that a tropical cyclone will develop in the western Caribbean by about the middle part of next week before it lifts northeastward across south Florida late next Thursday and along the US East Coast next Friday and next Saturday.

“The European model forecasts that an area of low pressure will develop about 300 miles east of Savannah, Georgia on Friday night and Saturday and forecasts this low pressure system to track west-southwestward towards the coast of northeast Florida by Sunday and Memorial Day.

“The NOGAPS model looks very similar to the NAM model as it forecasts that Invest 94-L will weaken as it tracks into the Gulf of Mexico on Thursday and redevelop along the coast of South Carolina on Friday. From there the NOGAPS model forecasts that this low pressure system will track southwestward along the coast of South Carolina during Saturday before tracking onto the Georgia coast on Sunday.

“At this point, I think development of Invest 94-L is unlikely today through Thursday due to very strong wind shear values. Now, should an area of low pressure develop along the US Southeast coast this weekend, some sort of sub-tropical or tropical development is possible as environmental conditions will be somewhat favourable for development and this is something that will need to be monitored closely.”

NWS forecasters in Miami predicted that our low pressure would produce 1-2 inches near Lake Okeechobee and 2-4 inches south and east of the lake, with isolated amounts of 3-5 inches.

Palm Beach International Airport tallied just 0.03 of an inch Tuesday, despite the threatening skies. But Miami-Dade was inundated, piling up 9.73 inches between 1 p.m. Tuesday and 7 a.m. Wednesday.

The 9.7 inches that fell on Tuesday easily washed away a 111-year-old record of 3.44 inches for the same date in 1901. So far this month, Miami has had 12.19 inches of rain, 9 inches over normal. At the Palm Beach airport, 5.48 inches have fallen in May (through Tuesday), 2.86 inches over normal.

A flood watch was posted for the Miami-Dade Wednesday morning as more moisture pushed up from the Keys, and the weather service said there was still lots of standing water left over from Tuesday’s drenching.

This activity in May, well before the hurricane system is as one blogger on www.wunderground says “if nothing else, is particularly interesting to me.” And me, too.

I leave the last word from Rob Lightbown:

“The GFS model’s forecast of a tropical cyclone developing in the western Caribbean around the middle part of next week may have some merit as the overall pattern favors lowering pressures over the far western Caribbean by next week. This will be something that we will keep a close eye on.”

Please support Crown Weather and go to:


Print Friendly, PDF & Email

Speak Your Mind