March 6, 2021

Weather News – Road Conditions – weather forecast

HURRICANE TUTORIAL THREE…ISSUED JAN. 31, 2021…3:00 P.M. EST

6 min read


Disclaimer:  This site is not affiliated with the National Hurricane Center, Hurricane Hunters, Storm Prediction Center, or National Weather Service.  ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.  As ALWAYS, follow the National Hurricane Center, National Weather Service, and your local Emergency Management officials for emergency decisions.  In addition, this is strictly a FORECAST OFFICE.  I CANNOT make decisions regarding travel plans, etc.  My purpose, is to provide you the information, based solely on information I analyze, and the accuracy of the information at hand of the time of analysis, so you may make informed decisions.
(T. F. “Storm” Walsh)

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Greetings to everyone!
Please be aware, even though I do not post every night, rest assured I am continuously monitoring various areas for any significant weather.  I will be taking Sundays off (family time), unless we have active systems that may be posing a threat (i.e. Tropical, Winter Weather, Coastal Storms, etc.).

This is the third in a series of hurricane tutorials.  This one will touch on hurricane storm surge.  I will post the links to the two previous tutorials in case anyone missed them.

Storm surge is considered the number one killer of a landfalling hurricane

The National Hurricane center defines storm surge as an abnormal rise of water generated by a storm, over and above the predicted astronomical tide.  Storm tide is defined as the water level rise during a storm due to the combination of storm surge and the astronomical tide.

If you click on the following graphic, it will take you to a PDF titled Introduction to Storm Surge:

INTRODUCTION TO STORM SURGE

The following link goes to a decent video from National Geographic on the topic of storm surge:
https://youtu.be/4gkIpmlFMLw

Storm surge can cause effects well inland, however residents along coastal areas are more at risk and can be in grave danger regarding storm surge, especially if storm surge reaches heights of 24.6 ft like experienced in Hurricane Camille (1969), or 28.0 ft as experienced with Hurricane Katrina (2005).  Below are photographs of the Richelieu Manor Apartments at Pass Christian, MS., before and after Camille’s passage.  This is where the “infamous” hurricane party was held:


I know…WOW!…Right?
STORM SURGE CAN BE DEADLY…10 TIPS TO BE READY (LINKED TO INFO)

This is why, if your area is placed under a mandatory evacuation order, DO NOT HESITATE…GET TO SAFE SHELTER!…KNOW YOUR EVACUATION / FLOOD ZONE!  This also applies if you live along  an inland waterway, that may be affected by water “pushed” into rivers, and waterways from the main storm surge.  This is why, I try to post probable storm surge values if time permits, with graphics from the SLOSH (Sea, Lake, and Overland Surges from Hurricanes) software program.  The following graphic is a sample output of projected storm surge values for Galveston Bay and surrounding areas during hurricane Ike:
SLOSH DISPLAY FOR IKE:

One note about the SLOSH display…in my training on the software, it was learned that SLOSH values are said to have an accuracy of plus or minus 20%.  For instance in the above graphic, Galveston Bay was calculated to receive between 6 to 8 feet of storm surge.  So, given the error of plus or minus 20%, an area projected to receive a 6.0 feet of storm surge, could experience a value of 4.8 ft to 7.2 ft.  This accounts for factors such as the strength of the hurricane category , (whether a minimal or top end in the category), direction of travel, mean tide or high tide, forward speed of the storm, and extent of the 39kt, 50kt, and 64kt+ winds radius, as well as storm diameter and contour of the ocean bed.   The following link is from the NHC, and explains the SLOSH program in some detail:
https://www.nhc.noaa.gov/surge/slosh.php#INUNDATION

I don’t know how many of you realize the following…we know Hurricane Camille was a category 5 storm at landfall, and Katrina was a category 3 storm at landfall but had a higher storm surge than Camille.  Some of you may be asking, how could this occur?  As we know, storm surge height has a lot to due with what I just covered in the previous paragraph.  Those factors produce what is termed as I.K.E. (not the hurricane).  I.K.E. is short for Integrated Kinetic Energy.  In simple terms, tropical cyclone destructive potential (Surge Destructive Potential) or (SDP) can be calculated by using the I.K.E. calculator.  The following link provides a PDF article on I.K.E:
https://www.aoml.noaa.gov/hrd/ike/Files/IntegratedEnergyPowell2.pdf

Generally, if time permits, I calculate that potential for you, and post it in the update.  The following link will take you to this calculator.  I don’t have the time to explain the process at the moment, however if you wish to email me, I will gladly walk you through it when I get time.
https://www.aoml.noaa.gov/hrd/ike/Calculator_AllQuad.php

IRT Katrina and other hurricanes…The Saffir-Simpson scale does not take into account the physical size of the hurricane, as far as destruction definition.  What has to be taken into account, at least for storm surge, is the size of the hurricane, the strength of the hurricane force winds and how far out from the center of the storm these winds extend.  For example, if a hurricane has hurricane force winds that extend out only 30nm from the center, the storm surge will be less than a hurricane that has the same winds extending out 75nm from the center.  In Katrina’s, she had been a category 5 hurricane with sustained winds of 175 mph just two and a half to three days prior to landfall.  So, in effect there was still energy and waves from a category 5 hurricane in the GOMEX, although she weakened to category 3 prior to landfall.  ALL of that energy as a CAT 5 did not dissipate prior to landfall.

Here are the links, to the 2 previous hurricane tutorials:
HURRICANE TUTORIAL ONE
https://stormw.wordpress.com/2021/01/03/hurricane-tutorial-number-one-issued-jan-03-2021-735-est/

HURRICANE TUTORIAL TWO:
https://stormw.wordpress.com/2021/01/16/hurricane-tutorial-two-issued-jan-16-2021-450-p-m-est/

You may direct any questions by contacting me personally, ANYTIME, at: twalsh22000@yahoo.com

Have a blessed evening!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS

 



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