BIRDSEYE VIEW POSTS

Since 2012 on the now retired Weather Underground blogs, I have been posting annotated "birdseye view" charts of the Atlantic basin, with a detailed explanation and forecasting that references the chart. From there you may know me as "NCHurricane2009." While I now do these "birdseye view" posts here, I will continue to do comments at Yale Climate Connections via Disqus where the former Weather Underground community has moved to. Feel free to reply to me there, at my Disqus feed at this link, or via e-mail at IOHurricanes@outlook.com 

 
 
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MY 2021 ATLANTIC HURRICANE SEASON BIRDSEYE VIEW POST #104A (Special Update)

*******Note that forecasts and outlooks in this post are NOT the official forecast from the National Hurricane Center (NHC). They are my own detailed views on the Atlantic tropics based on current observations and latest computer model runs. As such do not make decisions based on my posts...consult news media...watches and warnings from your local weather office...and any evacuation orders issued by local governments to make the most informed and best decisions. Visit the NHC website hurricanes.gov (hurricanes dot gov) for the latest watches/warnings and official forecasts on active tropical cyclones.**********


...UPDATE...WEDNESDAY SEPTEMBER 8 2021 5:28 PM EDT...

The National Hurricane Center (NHC) has upgraded the low pressure area approaching the Florida panhandle to Tropical Storm Mindy with 40 mph maximum sustained winds...a tropical storm warning has been raised from Mexico Beach to Steinhatchee River. An offshore buoy logged a small area tropical storm force winds just southeast of the surface center of rotation... which is the basis for declaring a tropical storm. I forecast that the center and small area of gusty winds will arrive onshore just west of Apalachicola...near or at Mexico Beach. The area further to the east...from Apalachicola to Steinhatchee River...I assess will have a lower chance of seeing tropical storm force winds as the center would have moved onshore and cause Mindy to weaken to a tropical depression as it continues east-northeast. However if Mindy manages to establish tropical storm force winds in offshore thunderstorm bands after the center moves ashore...gusty winds on the Florida panhandle east of Apalachicola cannot be ruled out. See update from 1:45 PM EDT for information on where Mindy may spread heavy rains with flash flooding potential through tomorrow.


...UPDATE...WEDNESDAY SEPTEMBER 8 2021 4:11 PM EDT...

The National Hurricane Center (NHC) outlook product has bumped up odds of development for the low pressure area approaching the Florida panhandle to 80%. The NHC may issue advisories on a tropical depression or tropical storm shortly. No changes to the list of impacts mentioned in the 1:45 PM EDT update below...as that list incorporates the possibility of a weak tropical storm forming.


...UPDATE...WEDNESDAY SEPTEMBER 8 2021 1:59 PM EDT...

The National Hurricane Center (NHC) outlook product has bumped up odds of development for the low pressure area approaching the Florida panhandle to 60%.


...WEDNESDAY SEPTEMBER 8 2021 1:45 PM EDT...

Satellite image of organizing low pressure area (tagged as Invest 91L) moving northeast to the Florida panhandle...taken at 1721Z:

The surface trough of low pressure in the Gulf of Mexico aided by the divergence zone of upper vorticity in the western Gulf has seen quick organization on the northeast side of the system through the morning and early afternoon hours. The CIMSS 850 mb vorticity product (http://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=vor&zoom=&time=) shows the mid-level rotation has consolidated within the organized thunderstorm bands... however ASCAT passes of surface wind did not sufficiently sample the area to make a conclusion about a surface circulation. However the most recent NHC TAFB surface analysis from 1200Z shows the northeast end of the surface trough has expanded and is aligned with the mid-level rotation. Therefore chances have sharply increased that a short-lived tropical depression or weak tropical storm could form before this system makes landfall on the Florida panhandle... and I have my raised my short-term odds of development to 80%. Based on radar and the latest satellite imagery...heavy rainfall with flash flooding potential will overspread the Florida panhandle... southeastern Alabama...southern Georgia...northeast Florida...and southern South Carolina through tomorrow. Gusty winds are possible on the Florida panhandle west of Apalachicola later today and into tomorrow.


For information on Hurricane Larry and the rest of the Atlantic tropics... refer to post #104 available on the home page of this site.

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