Loc: Austin, Tx
HUR FRANKLIN Lounge
Thu Jul 27 2017 12:22 PM
An active portion of the monsoon trof located in the east-central Tropical Atlantic and associated with a tropical wave has been showing some signs of developing one or two areas of low pressure that models increasingly suggest will interact with an additional wave, or waves plural, coming off of Africa later this week and/or next. Another consideration is an expected positive phase of both the MJO and CCKW crossing the Atlantic as we head into August.
Environmental conditions are already marginally favorable for development, and looked at from 50,000', this highlighted region is likely to become somewhat more favorable for tropical cyclone formation over the next three to ten days, and NHC does give it a 30% chance of development into a tropical cyclone within the next five (by early August), which could be conservative.
Quoting from this morning's TWD
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
652 AM EDT Thu Jul 27 2017
Based on 0600 UTC surface analysis and satellite imagery through 1015 UTC.
An eastern Atlantic tropical wave has its axis along 30W from 04N
to 17N, moving westward at an estimated 24 hour motion of about
10 kt. First visible METEOSAT images show what appears to be a
low to mid-level cyclonic circulation just west of the wave near
11N31W. Satellite images from during the overnight hours showed
and are still showing increasing convection over and near this
circulation. The convection is of the scattered moderate intensity
just north of where the wave crosses the monsoon trough from
11N-12N between 29W-31W. However, the METEOSAT-9 imagery shows
abundant dense Saharan dry air and dust across the wave north of
13N. Isolated showers and thunderstorms are elsewhere within 120
nm either side of the wave south of 13N.
July 30 Update
Early on July 28 this feature was tagged with an invest number, 97L, and the title of this Lounge thread was updated accordingly. However, that particular wave interaction fell apart, but as expected by some model runs, two new waves are now starting to interact and dominate, and slow development within this broad area of low pressure is becoming possible again during the new week.
August 3 Update
The more convectively active pocket of the Monsoon Trof has been dragged into the Caribbean with one of the expected waves, and some models are starting to sniff out development from this feature should it track into the Gulf of Mexico. This is now definitely something to watch over the weekend and into next week. The next Invest tag to be used here would be 90L
August 3rd 2 PM Update
As of the Aug 03 2PM NHC TWO, this disturbance is now being tracked as Invest 90L and the title has been updated accordingly.
August 6th 3:30 PM Update
Invest 90L is now being referred to as SEVEN and the title has been updated accordingly.
August 6th 10:45 PM Update
Ptnl SEVEN has become Tropical Storm Franklin.
This is where to put mid to long range thoughts on this feature's potential for development, intensity, and forecast track. Longer range model output discussions are appropriate here.