San Juan NWS report about Olga

[cycloneye]

As we know,Olga after passing Puerto Rico as a Subtropical system was classified as a pure Tropical Storm.What I am posting is only the review from the San Juan NWS of the impacts and observations when Olga moved thru the Puerto Rico and Virgin Islands area,not the NHC cyclone report.



This is an image of the 48 hour rainfall totals across Puerto Rico and the surrounding coastal waters associated with the passage of subtropical storm Olga. The color scheme in the upper left hand corner represents total rainfall, in inches, that was estimated to fall spatially across the area. The scale goes from 0.00” (black) to 15.00”+ (white). Radar estimates indicated the highest rainfall totals fell across the local Atlantic waters as well as across interior sections of Puerto Rico, with the coastal waters between the U.S. Virgin islands receiving the lowest rainfall accumulations.

Below is an excerpt of the report with the link to the full document also below.

Subtropical characteristics began to rapidly take shape as the low pressure system showed better signs of formation during the afternoon of Monday, December 10. The center of the system was just north of St. Thomas by the evening hours, moving over slightly warmer and shallower waters. This aligned it just under an Upper Level col of low pressure between two lobes of vorticity in high layers of the atmosphere. This was a critical step in Olga’s intensification process. By reducing the wind shear, it allowed the storm to close off its low level circulation and begin wrapping convection around its newly formed center. Communications increased between the WFO San Juan and the National Hurricane Center (NHC), whose hurricane specialists had been watching the storm closely around the clock and who had already issued a Special Tropical Disturbance Statement. The hurricane specialist had noticed tropical storm force sustained winds (35 knots, or 40 mph) at NOAA buoy 41403 located approximately 150 miles north of St. Thomas and winds at Cyril E. King Airport in St. Thomas were beginning to gust over to over 30 knots. At this time, convection was beginning to explode northwest of St. Thomas as cloud tops reaching 55-60 thousand feet were occurring nearing the rapidly deepening low center. As convection intensified, the low pressure center became significantly stronger as northwesterly flow on the northwest side of the system increased, allowing convection to push south towards the northern coast of Puerto Rico.

Also see radar movies at link

San Juan NWS review of Olgas impact in Puerto Rico/Virgin Islands

[brunota2003]

Wow! That was a pretty good read, and I enjoyed it. Thanks for passing along. I like how they saved the radar images and turned them into little movies. I'll have to download those later and view them.

[cycloneye]

Its always interesting to revive memories on how the systems formed and in this case how Olga formed in December.By seeing this in my view,it will be interesting to see if this is a trend that we will see in the comming years about having systems forming after November 30 arrives as this has occured in the past few years.

[brunota2003]

I believe that they've been there all along. But with newer sat images with higher resolution, we've been able to pick up on more and more of the late bloomers. Plus, satellites can pick out warm cores versus cold cores now, making it even easier to identify the systems.

EDIT: To remove the "quote" I had, since we are the only two posting in here, so far and quotes are unneeded in this case.