September 7: Forecast Update for Hurricane Leslie

     As most of you have heard by now, the tropical system named Leslie has been churning in the Atlantic for over a week. She has been slow-moving, only moving a couple hundred of miles northward since Monday morning. We will be taking a look at what is in store for the future of this system.

Infrared image of Leslie at 7:45 EDT September 8 courtesy of CIMSS

     As of 2 PM AST, Leslie was downgraded to tropical storm status by the National Hurricane Center, with sustained winds at 65 mph. Leslie has been struggling with organization over the past week. Vertical wind shear aloft over the last few days has been preventing strong convective development. Now, slow propagation northward due to little or no steering currents has caused upwelling of cold waters; this has lead to the weakening of the system in the past 24 hours.

     Over the next 36 hours, Leslie should move northward over waters with ample warmth allowing it to restrengthen in an environment with little vertical shear. The latest runs of the GFS, ECMWF, HWRF, and GFDL models have all suggested that the storm will reach wind speeds of up to 92 mph in that time, insisting category 2 strength. The extensive mid-level trough currently moving eastward across the United States will accelerate the steering winds south of Leslie, pushing it north-northeastward. 

ECMWF model output graphics courtesy of WeatherBELL Models

     As of now, models are having the storm sparing Bermuda from direct impact, passing just east of the island. As it moves northeast into higher latitudes at an increasing rate, cooler waters and wind shear will weaken Leslie considerably. Models 96 hours out then suggest an interaction with Hurricane Michael, illustrated by the 12Z run of the ECMWF model (pictured left). This interaction would lead Leslie to deflect into a more northerly path. This northerly track would put Leslie in line for landfall in Newfoundland, impacting cities such as St. John's and Saint-Pierre. The 18Z model ensemble on the tracking of Leslie is noted below. The majority of the models are hinting landfall near St. John's, Newfoundland.

Model ensembles courtesy of http://derecho.math.uwm.edu/models/

     For us at Stratustatus, Leslie is forecast to become a weak category 2 hurricane before being carried away by the southerly flow of the incoming mid-level trough. The system will weaken gradually as it moves northeastward past Bermuda into the higher midlatitudes. Michael, which will likely be a tropical storm, will interact with Leslie, causing Leslie to take a northern trajectory towards the eastern portion of Newfoundland. Leslie will potentially make landfall near St. John's, likely as a tropical storm by Wednesday, September 12th. This forecast will be updated when necessary.

See our previous forecast here: http://stratustatus.blogspot.com/2012/08/forecast-for-tropical-storm-leslie.html

Living in the Midwest

During our daily look at the models we noticed a rather large event on the way.  A higher pressure system is sitting out over the western plains pushing a front eastward into the Midwest.

                                                 http://www.wunderground.com/maps/

Right now the storms are already stretched out long enough to cover a couple states.  As the storms push eastward into the evening models suggest they will strengthen.  At around 23z(7pm eastern) the storms are stretching from Oklahoma through Indiana.

                                              (high resolution rapid refresh from NOAA)

In the next 4 hours the storms strengthen quickly and pretty much cover the state of Indiana and also cover large portions of Illinois and Kentucky.

                                                                3z(11 pm eastern)

Through out The night it will weaken as it moves in a more north eastern direction.

The main issues associated with this storm are going to be wind and rain.  It will be happening overnight on a well known day of celebration(happy weekend to all)  as well which will complicate the situation.  Just remember to drive safe and smart.

Looking into tomorrow these storms look like they are going to push into the east coast bringing rain stretching from Maine all the way down to Georgia.

Isaac?...Isaac?....Is that you?

         While getting our daily fill of weather related websites, us at Stratustatus stumbled upon a rather unique hashed area of thunderstorms, on the National Hurricane Center website. It was not your typical tropical wave off the coast of Africa. The wave actually was coming off the coastlines of Florida, Alabama, and Mississippi! This phenomenon led us to wonder if this was in fact Isaac double dipping back into the Gulf of Mexico.

        We haven’t been the only ones inquiring about this system. The National Hurricane Center released this statement on their Facebook today. The below excerpt provides the NHC’s technical ruling on this tropical wave.  

http://www.facebook.com/US.NOAA.NationalHurricaneCenter.gov

       This is the verdict issued by the NHC. If this system forms into a tropical storm it will take on a new name because its not the primary remnant. How do you guys feel about this ruling? Stratustatus is currently a split jury on this topic. One could argue that if any part of this system originated with Isaac it should renamed the same system. On the other side the NHC has a very valid point if both parts of the system were to re-form. Their ruling would grant the name of Isaac to the primary remnant of the system and tag a new name to the secondary remnant. 

http://www.wunderground.com/tropical/tracking/at201290_model.html

       This system in the Gulf could be the next named storm in the Atlantic Hurricane season, but we won't jump the gun quite yet. The invest currently has about a 40% chance of developing over the next 48 hours. There is not a good indication on the computer models as to where this low will move over the next five days. This remnant of Isaac will not intensify to its former self, but this possible re-development looks to be a very unique story in the world of weather. 

Initial Logo Designs are In!

Hey everyone our initial mock logo designs are in. There are some pretty promising logos. We are currently narrowing down our choices for the design team. Once this happens they will go more in depth with the creativity of two or three logos. Stratustatus hopes that the finished logo will be implemented by the end of next week if not sooner. We will keep you posted and may give some sneak peak looks at our final two or three logos that we may choose. Thanks for tuning in and keep your head in the clouds.

The Tough Times of Forecasting Isaac

          Tropical storm Isaac was the first hurricane to make direct U.S. landfall this year. It was a storm of unusual timing and confusion, which led to the extreme amount of media coverage over the past week.

TS Isaac managed to delay the RNC

          The timing of this system could not have been worse. Earlier this week Isaac managed to postpone the Republican National Convention in Tampa, Florida, while school systems in Southern Florida cancelled their Monday classes. Once all of this mitigation was in place Isaac ironically managed to spare much of the Eastern coastline of Florida minus the Keys.

           Much chaos surrounded the actual projected path of Isaac as it made its way into the Caribbean. Weather computer models had anything from the storm brushing up against the Atlantic coast to making direct landfall in Louisiana. The path of Isaac was directly correlated with the speed and strength of a high pressure ridge, which was predicted to make its way across the United States. Three different weather models (complex equations that predict future conditions of the atmosphere) pushed out different results. The Canadian Model predicted that this ridge of high pressure would drive Isaac on a more eastern path into the Atlantic Ocean. The European Weather Modeling system believed that the ridge would dissipate causing Isaac to break into the middle of the Gulf of Mexico. The United States weather model, known as the GFS, predicted a path that would directly impact Florida. These models helped generate the cone of uncertainty of the system.

Wx Models had Isaac making landfall anywhere from New York to Louisiana

         The Weather-computing model that ended up winning out was the European Model, which has supposedly been the most accurate at tropical forecasting in the recent years. The next difficult task, which meteorologists faced, was predicting the intensity of the storm. The storm initially was to be at hurricane strength shortly after passing through the Florida Keys. The initial hypothesis suggested that Isaac would be a strong category 2 hurricane at landfall. In order for it to be classified a category 2 storm the winds must be between 96-110 miles per hour, which brings with it storm surge of 6 -8 feet. Over time, it became evident that the storm was battling dry air entrainment (dry air entering a moist system) and wind shear (Different direction or speeds of winds at different levels of the atmosphere, which can cause weak cloud structure). Both of these factors often inhibit intensification of a tropical system.

           Wind speed slowly intensified while the storm rapidly dropped in pressure. Pressure of the storm is loosely correlated with a tropical system’s wind speed. As Tropical Storm Isaac slowly inched his way to landfall the pressure dropped to a typical category 2 hurricane, which puzzled many meteorologists. Isaac broke a North Atlantic record for having the lowest pressure level ever recorded in a Tropical Storm. There was much disagreement among meteorologists as to when it should have been dubbed a hurricane. The National Hurricane Center felt that the classification system should be a cut and dry yes or no decision. Others felt that there were winds somewhere in the system at hurricane strength and that hurricane status should have been issued early Tuesday morning to urge lingering residents to evacuate low-lying locations of Southeastern Louisiana. 

          Early Tuesday afternoon Tropical Storm Isaac upgraded his status and a hurricane was born. The system’s strongest winds topped out at 80 miles per hour as it slammed the Louisiana, Mississippi, and Alabama coastlines. The hurricane managed to generate enough surge to top 8 foot levees, which left many residents on their rooftops awaiting rescue. New Orleans had rainfall totals that topped 20 inches. Others storm totals can be seen here: http://www.nola.com/hurricane/index.ssf/2012/08/isaacs_rainfall_totals_through.html

ABC News

          The storm has now transitioned into a Tropical Depression as it moves into the Midwest just in time for Labor Day weekend. Locations of Indiana, Ohio, and Illinois should expect a rainfall total ranging from 1-5 inches over the next few days. CNN Money has already released an article stating that the destruction caused by Isaac could hit 2 Billion dollars in damage. See here: http://money.cnn.com/2012/08/31/news/economy/isaac-damages/

          Even though Hurricane Isaac is no more, individuals should be wary for the continuation of activity in the Atlantic Ocean. The months of September and October are generally the most active of Hurricane season. The ocean waters are warmest in the Atlantic and Gulf of Mexico during this time year. 

Forecast for Tropical Storm Leslie

This hurricane season has been rather active over the past few weeks. Another tropical system was named on Thursday: Leslie. This system has strengthened quite a bit over the past 24 hours, and is moving westward across the low latitudes of the Atlantic. Most models agree that Leslie will intensify into a weak to moderate hurricane over the next few days, curving northward into open waters. However, the latest ECMWF model is differing from the others, the same as it did in the case of Hurricane Isaac.

At 2 PM EDT Saturday, Leslie can be seen in the mid-Atlantic just east of the Lesser Antilles curving northward. At this point the Euro is in agreement with the tracking of the system.

Now here is where the ECMWF differs. The model picks up a dome of high pressure forming north of the system (circled in red) on Wednesday afternoon. This high pressure stalls Leslie in the Atlantic, allowing for it to intensify over warm waters at around 29 degrees Celsius.

As this system stalls, a surface low pressure system comes off the eastern U.S. and begins to interact with the circulation of Leslie. Due to the cyclonic flow of this new low pressure system, this interaction causes Leslie to move north-northwestward towards the upper Northeast states.

 This is the final output of the 12Z Euro run for the afternoon of Sunday, Sept. 8. Here, Leslie is a weak category 2 hurricane just off the coast of Maine. It appears after this, according to other model outputs, the storm gets caught in the jet stream, taking it back out to sea.
As one could imagine, this is a long way out, so this model will not likely hold true. However, the Euro has been the most accurate in forecasting hurricane tracks in recent years. It will be interesting to see how this plays out over the upcoming week.

Ball State Storm Chase Course

A good article by the Ball State Daily News on Ball State's own Summer Storm Chase Course that many of my friends took part in. They all seemed to have a good time regardless of the amount of storms they may have witnessed.