Archive for the ‘Central Florida Weather’ Tag

IRMA POSTING – PLUS

– click mouse twice for full enlargement of this image –

 

 

FIRST ENTRY IN MORE THAN A YEAR – 9-6-2017

I apologize to those few of you who have been consulting this weblog. My last posting was August 31, 2016. I’m still going strong and my interest has not waned. I’m still in the learning mode and intend to stay there. But it’s been a long time since I retired from teaching full-time college geosciences in 2003 and a lot has changed. I continued adjunct teaching after I retired but then moved away from South Florida in 2005. From 2006 into 2013 I taught 14 short-term courses at the College of Central Florida. Interest in this weblog seems to have diminished since I stopped formal teaching. However, when I checked this site this morning I saw that it has gotten tons of hits over the last few days, probably due to hurricane Irma. Prior to this current event almost all geoscience questions and observations that have come my way have been from a few family members, a few neighbors, and one buddy at church. It is very rare for me to hear from former students.

In-so-far as weather reporting is concerned, the information available to the public has blossomed since I retired and, for the most part, its quality has improved to the point that there is little if anything I can add (beyond basics). Many of my notions concerning tropical weather events fall into the category of hunches or intuition. I don’t believe that my 37 years of teaching meteorology full-time gives me license to clutter minds with my ideas unless I’m honest about them. Instead, in the comments below about Irma, I will share the four tropical weather resources I consult most often.

I am planning a change of theme and/or purpose for this site soon – more in the realm of discovery, opinions, observations, analyses, experiences, and perhaps some attempts at humor. The “About” page for this site was updated earlier today and if you wish to contact me, you will find my address there.

 

 

MY INPUT ON OUR CURRENT TROPICAL WEATHER

WHICH IS BEING DOMINATED BY HURRICANE IRMA.

My four primary resources are:

  1. Dr. Jeff Masters’ weblog (blog) at WeatherUnderground.com. It can be found here: https://wwwwunderground.com/cat6

  2. The Weather Channel on television and on-line – including apps. There are things about the Weather Channel presentations I don’t like. Nevertheless I appreciate the convenience and their efforts.

  3. The National Hurricane Center. I go to this site to get a grip on what is going on in their world. I consider that they might tend to err on the side of caution, subconsciously at the very least. What an awesome responsibility they have. Http://www.nhc.noaa.gov/

  4. The ECMWF Model – commonly referred to as the European Model.

I rely upon it heavily because of it’s premier reputation due to its accuracy over the last few years. It has done well for the “Irma type” storms. To be sure, I don’t ignore the other models. The following paragraph is for those who have been trying to understand that model.

You are likely to have heard many references to the European Model. I admit it is confusing. For example, here is a quote from Dr. Jeff Masters. “The European Center does not permit public display of tropical storm positions from their hurricane tracking module of their model, so we are unable to put ECMWF forecasts on our computer model forecast page that plots positions from other major models.” Thus, even though on television or on-line you may see comparisons of the European Model to the myriad other models, you might have noticed that it’s not included in the spaghetti charts that show models from multiple sources. What you will see is either the European “operational” model track or the European Ensemble (a spaghetti graphic). For that spaghetti ensemble the operational model is re-run at a lower resolution (called the control run) and this is then repeated 50 times, each with slightly different starting conditions.

I get my favorite animated European model track from Penn State’s Department of Meteorology at http://mp1.met.psu.edu/~fxg1/ECMWF0.5_0z/ecmwfloop.html

Please note that this link is time-sensitive.

Of the four charts, I focus upon the one on the upper right as I scroll through f24 through f240 ( which means “24 hours into the future” through “240 hours into the future”).

You might fry your brain with the time signatures on the bottom – depending upon your comfort level with time at the prime meridian (Universal, Greenwich, Zulu) and your knowledge of Victor time.

 

THE CORIOLIS EFFECT

I’ve been thinking all day long about the Coriolis Effect as it relates to Irma. If you are my former student you might recall that the steering currents at high altitude are, in part, a function of the Coriolis Effect (the Penn State chart on the upper left) and I’ll bet you remember that the counterclockwise circulation of Irma is due to the Coriolis Effect. If you’re still sharp on the subject you might also remember that the outflow at the top of the storm is likely to be clockwise for the same reason – the Coriolis Effect. I know that sounds like a contradiction to those of you who are unfamiliar with this subject. If you are interested in the Coriolis Effect go here:

https://cloudman23.wordpress.com/2008/10/02/the-coriolis-effect-in-the-real-world-a-tutorial-part-1/

and here:

https://cloudman23.wordpress.com/2008/10/07/the-coriolis-effect-in-the-real-world-a-tutorial-part-2-cyclones-anticyclones/

 

MY NOTIONS TODAY ABOUT IRMA

Here is my zinger that comes from the “gut level” and is therefore probably not deserving of any classification other than “pure speculation.” (That’s the honesty I referred to in the second paragraph of this blog).

I am expecting (or is it hoping and praying for?) slightly more turning to the right than the experts are indicating. The itty-bitty turn last night was encouraging to me. I keep telling myself that the hurricane is a separate entity of its own and that the Coriolis Effect is influencing it’s path independent of the steering currents and the rotational motion. That path is the consequence of what is referred to as translational motion. Furthermore, the further north the storm gets, the stronger the Coriolis Effect will be. The Coriolis Effect is zero at the equator and increases to 100% at the poles. Maybe I’m just overly excited about last night’s noticeable veering of Irma’s path. Perhaps this is merely a good example of wishful thinking. We’ll see.

 

FOR CITRUS COUNTY, FLORIDA

Finally, for those of you who live in my county of Florida, Citrus, you might be interested in this August 2014 posting about hurricanes.

https://cloudman23.wordpress.com/2014/08/22/citrus-county-florida-and-hurricanes/

 

 

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Debby Does the Gulf

– two left clicks will fully enlarge –

For the last few days, weak tropical storm Debbie has been slowly working her way northward keeping residents of the Gulf coastal states on alert.  A huge volume of warm, moist air, some originating all the way from the eastern Pacific (see image above), has been racing northeastward and northward into the storm’s core generating numerous alarming situations conducive to tornadic development.  The environment around her has made it very difficult for forecasters to interpret the numerous computer tracking models because there has been little agreement.

At this moment, (6-25-2012) about 2 pm Eastern time, it looks as though she will extend her stay over the Gulf well into the week and eventually work her way eastward to cross Florida and then enter the Atlantic.  Where I live in Citrus County, Florida that means we could experience the right-hand leading quadrant of the system.  It is that particular quadrant of northern hemisphere tropical systems that usually has the highest wind velocities and the greatest probability for tornadoes and significant sea surges upon the shore.  However, I am optimistic that upwelling of cooler water in the Gulf below the storm will further diminish the strength of the storm.  Typically, when strong winds skim over warm water and push it aside, that which takes its place is cooler water that “wells up” from below.

There are many factors that can cause a tropical system such as Debby to strengthen and/or weaken – the sea surface temperature changes being but one.  However, it is my hope that she does provide us more much-needed rain in a slow and steady manner so that it infiltrates into our groundwater zone instead of  traveling as surface runoff.   I hope she does decide to take that trip across Florida and that she will be sufficiently mild-mannered to be a great benefit to the region.

Enjoy the satellite view above which shows the extent of Debby’s influence this morning (6-25-2012).

IDA – FORECAST PLOT RELEASED 11-9-09 NOON CST

Ida’s most recent forecast plot as presented by WeatherUnderground.com.


Ida11-9-09-11-9-09 12nCSTLeft click the image to enlarge.

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Central Florida’s Hard Freeze! What Is Happening?

Two independent left clicks should enlarge this image considerably.

Two independent left clicks should enlarge this image considerably.

LIKE MOST POSTING ON THIS WEBLOG, WITH THE EXCEPTION OF THE TUTORIAL PORTION, THIS IS TIME-SENSITIVE.  EVEN ONE DAY CAN MAKE A BIG DIFFERENCE SO IF YOU ARE NOT READING THIS CLOSE TO THE POSTING TIME, PLEASE CONSULT YOUR LOCAL MEDIA OR ON-LINE RESOURCES FOR UPDATES.

I’m posting this on the evening of January 21, 2009 from my home in Citrus County, Florida.  22 miles NE of my location is Ocala; 12 miles SSE is Inverness.

Forecasts for the low tomorrow morning in this part of Central Florida (specifically, the town of Hernando) range from 18 degrees to 24 degrees Fahrenheit (depending upon the source).  Though that may seem to be a broad range it is quite possible to find those two ends of the forecasts both a reality within a very small area – arguably, less than a quarter-section (1/2 mile by 1/2 mile square).  This is due to the highly variable properties of unlike surfaces (heterogeneous surfaces) when it comes to the loss of thermal energy via infrared radiation.

On a larger scale, the satellite image above, completed at 3:45 P.M. E.S.T. today shows Florida virtually cloud free.  This means that all during the daylight hours, even though solar radiation was pouring in, terrestrial (earth) radiation was flowing out freely in the form of infrared – much more freely and abundantly than it would have had the air been humid and had clouds been present.  Tonight, the infrared will continue escaping in its space-bound journey.  The moisture content of the air is low and there will be no clouds though there could be fog (technically speaking, fog is a cloud).

Water vapor (water in the invisible gaseous state) is the most active and abundant of the so-called greenhouse gases.  The presence of clouds suggests that up at that level there is plenty of water vapor (that which resides between and below the cloud droplets that has not condensed into cloud droplets).  So, on a humid, cloudy day one would expect a strong greenhouse effect keeping thermal energy “trapped” at the lower levels.  BUT – TONIGHT THAT IS NOT GOING TO HAPPEN because, as stated, the air is dry and cloud free.  Tonight heat will be escaping rapidly and little will be sent back and none will be pouring in from the sun.  So – the temperature will drop dramatically.

Typically, there is about a 30 minute period after sunrise when the thermal energy escaping earth’s surface at that location exceeds the amount of thermal energy coming in from the sun.  That is why the coldest moment of a 24 hour period is most often after sunrise – about 30 minutes or so.

The satellite image shows how once the cold air coming down from a component of the north leaves the continent to flow over the Atlantic and Gulf of Mexico, moisture is picked up and clouds form.  Notice how they form in short order leaving only a narrow cloud free zone over water near the land.  The fact that the water surfaces are warmer than the continental surfaces at this time of year also play a role in that cloud development.

CONNECTION DIFFICULTIES – Cloudman23 – Oct. 17, 2008

MY NEW TITLE FOR THE IMAGE ABOVE IS – “WILL HE EVER GET BACK ON LINE?”

This post is for the purpose of letting my “regulars,” mostly friends interested in tropical weather or family members looking in to see what’s happening, know that I am currently dependent upon a very weak wireless signal up here in the mountains.  On my retirement budget I can’t justify at this time the expense of a more sophisticated and reliable connection.  The signal I get, in addition to being weak, is intermittent.  This is the first time I’ve been able to get on line since yesterday morning.  So – if there is inactivity, please know that all is O.K.  I hope that all is O.K. for you too.  My only weather source under these conditions is the weather channel but my ability to communicate with you is temporarily very limited.  I hope, within the next few days, to be able to improve the situation.

Yours Truly,

Tonie Toney