Good evening. Post would have been up sooner, except PC problems…talk about SLOW!
As of the 10:40 P.M. EDT Tropical Weather Outlook from the NHC, probabilities of Tropical Disturbance INVEST 98L becoming a tropical cyclone during the next 48 hours has increased to HIGH (70%).
Current satellite imagery, and satellite loop images indicate 98L has become slightly better organized over the past 6 hours, with a slight increase of convection near the center. Satellite imagery also indicates this system may be trying to develop a small CDO, as what appears to be a semi ring near the center.
The disturbance is moving to the WNW, and I expect this motion to continue for the next 48-60 hours, before the subtropical ridge becomes more oriented east to west, and nudges westward each day as presented int he current run of the forecast steering layers maps.
Based on analysis of current and forecast steering layers maps, I am concurring with the dynamic model guidance, and still prefer a rack with a blend of the TVCC, TVCN, and AEMI track guidance. Track thereafter or past 72 hours can change quickly. However, on the last two frames of the forecast steering maps loop, the subtropical ridge is shown elongating and pushing it’s nose slightly further west with each frame.
Current wind shear depicts a semi upper level anticyclone at the moment, however winds are light enough to allow further intensification of this disturbance. In fact, as of the typing of this synopsis, the NHC increased the probability for development to 70%, and will be reflected in the graphical TWO.
NHC had indicated the presence of some wind shear after tomorrow, along with cooler sst’s, which would inhibit further organization. However, based on model guidance shifting further south, it will hit cooler sst’s, however the disturbance may be over these cooler temps shorter than anticipated earlier.
In regards to wind shear, I’m scratching my head trying to figure this one out. The 18Z run of the GFS Zonal Shear forecast does indicate a weakening of the upper level anticyclone, but brings it back about 12 hours after it diminishes. Based on analysis of the zonal shear forecast, and future forecast track, it appears 98L will be in semi conducive, to conducive upper pattern over the next 5 days, with little to no zonal shear, and redevelopment of the upper level anticyclone. This has been consistent in the 3 consecutive runs today. Based on these factors, I am calling for a possible halt to intensification after tomorrow, for a brief period, and believe, should forecast conditions hold true, a re-intensification of this system after 48 hours.
Based on information contained in the TWO, this system may become a tropical depression, or even a tropical storm by morning, if the current convective trend continues.
I will have another update in the a.m.
Have a great night!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)