Currently formerly known as Tropical Storm Ernesto is now a category 1 hurricane and GeoEnvironmental Forecaster Braxton Snow is currently reporting live from the storm in Cancun, Mexico. Braxton has informed the team the following:
“Windy conditions continue to take place here in Cancun, Mexico. Winds up to 65 mph sustained are still ongoing to this very minute as the hurricane has been beginning to make a landfall about 75 miles to the south of Cancun. Hurricane force winds aren’t expected here in Cancun but some very intense winds will remain to take place into much of the overnight timeframe. Due to landfall taking place within the next several hours, the surge is at its peak height around 12-15 feet here in Cancun. Some minor damage has been taking place throughout the past couple of hours but nothing too major. Flight delays may become possible tomorrow morning and through a portion of tomorrow afternoon for many airports in the Yucatan Peninsula so make sure to check your flight information throughout the day tomorrow.“
Braxton looks to send the team on storm footage of video and photo imagery into the day Wednesday as Ernesto tracks inland and Westward.
Hurricane Ernesto (10:15 CST PM National Hurricane Center Advisory)
In time, larger scale storm systems will allow the organization to exhibit some of their in-depth analysis to break down what effect a disturbance will have on the “land beneath the clouds”. In doing so this enables a different set of packages the team can provide for viewers to see and use if in threat.
In this update, Hurricane Ernesto is making landfall. Landfall from any storm can cause a plethora of factors including strong damaging winds, heavy flooding rains, and more accumulating problems overtime. What the team looks to do is give you in an example what analysis and GIS skills from GeoEnvironmental Atmosphere can do when a storm is at large.
The Factors Of Ernesto
Firstly let us take a look below at four images that both share a common characteristic, they are topographic images of land that is currently being affected by Ernesto. Each image helps the team analyze on a certain factor and issue. When Ernesto was forecast to aim landfall toward this region the team began asking questions. Some including:
What effect will the elevation have on the intensity of the storm as it moves over land?
The topography maps that the team used below show that some to very little hills exist over the directly tracked area (brown =flat and yellow/green= high terrain). This gave the team a better sense that Ernesto would easily be able to keep enough strength to stay a tropical storm through Wednesday. However, Ernesto will lose hurricane status unable to get a consistent flux of coiled moisture from the ocean. Aside from strength the team also brings thought to less elevation would lead to less obstacles holding winds from slowing and so concerns remain high to not only flooding but wind damage.
Where will flooding become most of a concern across the region?
Geography is very important in determining such an issue. Flooding can occur over flat land and also in the most notorious way over Latin America, from elevation. In this image or the fourth and last map, the team was able to use a brightly covered topographic map overlaying not just river and streams from all over the region but only the following on the map released by the momentum of elevation. A deeper analysis will illustrate that further North where land is flat across the Yucatan is where water bodies do not extend as inland but further South and the brighter color of pink and purple lies where the highest elevation remains. When a larger disturbance tracks over a location it has a greater chance of causing flooding from where elevation is highest and down hill due to not only orographic lift slowing down the movement of the clouds and precipitation but also the momentum of rushing water downhill. Given this location of pink and purple there is a concern for water bodies to flood especially over a high concentration of elevation.
How many people are looked to be affected by this hurricane directly?
So many factors that the team spoke of affect people, without people and a daily population amount there is no telling the real effects that storms such as Ernesto will and have produced. When we take a lokok at the population map (white to red indicating low to high population) we can observed that the highest living area of people live over the Northern fringes of the Yucatan. Fortunately, less people among a large population will not be as badly affected given the track but still smaller towns remain in the direct path and most are of less prepared unlike larger cities.
The final end product to our analysis is adding all layers over each other to find in correlation to what the team talked about regarding population, flooding, damaging winds and the worst concern. Below we can observe North of this track gets off easier where the highest population remains, but North and East of Ernesto is where worst winds will remain. Flatter elevation will cause more concern to wind damage. Of course rainfall will also be heavy but in bands because of the distance further from the centered eye. Closer toward the track Ernesto looks to come on shore over flatter terrain but eventually find itself over some hills during the day Wednesday. As stated above this is a contributor to flooding especially down hill. Some of the heaviest and most consistent rains will also stick closer toward the eye. The concern in the cone forecast area is both flooding and damaging winds.
The Future Of Ernesto
The team has been bringing Hurricane Ernesto’s projected track South, and that is due to a simple, but often overlooked feature by many forecasters. Below is a picture of the 200mb to 700mb Mean Wind Flow, as of overnight Wednesday:
The team sees that there is an anticyclonic wind flow to the north of Hurricane Ernesto, which is the reason that Ernesto is traveling due West. The two systems will travel the path of least interference, and thus the due West track.
After Hurricane Ernesto impacts the Yucatan Peninsula, it will travel West and intensify due to the favorable environment. Current water temperatures are well over the 26 degree Celsius line (78.6 degrees Fahrenheit) that is essential for tropical cyclones to form and continue. Though hurricane intensity is not expected.
(Below is a graphic that will depict the strength and the efficiency of the tropical cyclone heat engine efficiency):
Note: Start (A) Current Position (C) End of Model Run (Z)
Note: The 26 degrees Celsius line can be found in the top left of the graphic below.
Notice how the thermal wind between the two heights is indicative of a warm core storm, and as the storm has a “deeper” warm core, the system will drop in pressure, therefore increasing the Pressure Gradient Force (PGF) between the eye and the surrounding areas, causing air parcels (from a high pressure) to rush into the storm (in an attempt to maintain equilibrium). This increase in wind speed increases the amount of latent heat that is released into the atmosphere, and also increasing the temperature difference (delta) between the warm updrafts (heat rise), and upper atmosphere of the cyclone (heat sink).
Notice how when Hurricane Ernesto moves over land, the pressure does not decrease because of the low level friction and decrease in latent heat release.
“It must also avoid encounter with any land mass because it will lose the source of energy (latent heat) and will encounter friction, slowing, creating disorganization within it, and therefore dissipating it.”
Afterwards, when Ernesto moves over warmer water, the system will get a “jumpstart” and will intensify rapidly, and impact Northwestern Mexico about 400 miles South of Brownsville, Texas, bringing the system heavy rain and Hurricane force winds.
Although rapid intensification is expected, the team does stress that Hurricane Ernesto will encounter shear ahead of it, which will limit it. Below is a graphic on current shear tendency:
In this image the warmer colors indicate where shear is likely or have a tendency (favorable) to occur over. Where the hurricane marker sits there is little to no shear but off toward West and South Gulf tendency increases and so this is the reason why the team believes Ernesto is unlikely to reach hurricane status as it reaches Gulf waters but instead keep around tropical storm status.
By later Wednesday the team will begin to finish off forecasting Ernesto in determining where and if Ernesto reaches the Gulf to threaten a second landfall. Stay tuned for more information regarding Ernesto at www.geoea.org