Cloud Stalker: So it begins

Friday, May 15, 2020

So it begins

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL

210 PM EDT Fri May 15 2020

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Special Tropical Weather Outlook issued to discuss the potential 
for tropical or subtropical development near the northwest Bahamas. 

1. Satellite data and surface observations indicate that the trough of 
low pressure located over the Straits of Florida has generally 
changed little today.  This system continues to produce 
a large area of disorganized shower activity and gusty winds 
across the Florida Keys, portions of southeast Florida, and 
the northwestern Bahamas.  Gradual development of this system is 
still expected, and it will likely become a tropical or subtropical 
storm on Saturday when it is located near the northwestern Bahamas. 
Later in the weekend and early next week, the system is expected to 
move generally northeastward over the western Atlantic.

Regardless of development, the disturbance will continue to bring 
heavy rainfall and wind gusts to tropical-storm-force across 
portions of the Florida Keys, southeast Florida and the Bahamas 
through Saturday.  In addition, hazardous marine conditions are 
expected along the Florida east coast and in the Bahamas where Gale 
Warnings are in effect.  Dangerous surf conditions and rip currents 
are possible along portions of the southeast U.S. coast this 
weekend and early next week.  See products from your local weather 
office and High Seas Forecasts for more details. An Air Force 
Reserve Hurricane Hunter aircraft is scheduled to investigate the 
disturbance tomorrow morning, if necessary. The next Special 
Tropical Weather Outlook on this system will be issued by 9 PM EDT 
tonight, or earlier, if necessary.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...80 percent.

High Seas Forecasts issued by the National Weather Service can be 
found under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and 
available on the Web at ocean.weather.gov/shtml/NFDHSFAT1.shtml.

Forecaster Cangialosi

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HAIL (3/4 inch or greater)

Hail can cause significant damage to your vehicle, break windows and damage roofs of homes and businesses.
Hail can cause significant bodily injuries such as broken bones and even blindness if wind blown.
Softball (4.5 inches) sized hail was reported in Lake Wales, Florida on March 30, 1996.
Haildrifts, up to four feet deep of dime to nickel sized hail, occurred in low-lying areas near Zephyrhills, Florida on January 29, 1997.
Hailstones the size of softballs can fall at speeds faster than 100 mph

supercell

Supercells derive their rotation through tilting of horizontal vorticity (an invisible horizontal vortex) caused by wind shear. Strong updrafts lift the air turning about a horizontal axis and cause this air to turn about a vertical axis. This forms the deep rotating updraft, the mesocyclone.
A cap or capping inversion is usually required to form a downdraft of sufficient strength. The cap puts an inverted (warm-above-cold) layer above a normal (cold-above-warm) boundary layer, and by preventing warm surface air from sinking too far, allows one or both of the following:
Air below the cap warms and/or becomes more moist
Air above the cap cools
This creates a warmer, moister layer below a cooler layer, which is increasingly unstable (because warm air is less dense and tends to rise). When the cap weakens or moves, explosive development follows.
In North America, supercells usually show up on Doppler radar as starting at a point or hook shape on the southwestern side, fanning out to the northeast. The heaviest precipitation is usually on the southwest side, ending abruptly short of the rain-free updraft base or main updraft (not visible to radar). The rear flank downdraft, or RFD, carries precipitation counterclockwise around the north and northwest side of the updraft base, producing a "hook echo" that indicates the presence of a mesocyclone.