ISAAC MAKES LANDFALL

In-house radar imagery suggests that Hurricane Isaac made its first landfall on Louisiana soil just after 6:00 PM CT this evening as a Category 1 hurricane.

The eye made it onto land at that time, now on its way to the major landfall on the main Louisiana soil. I will have more detail on this later, as well as verification on my forecasts and projected paths of Isaac.

Andrew

Horrendous Flooding Situation Setting Up in Central Gulf Coast

A horrendous flooding situation is setting up in the central Gulf Coast over the next couple days, as Isaac crawls ashore and stays in place for hours on hours. Here's a new forecast from the WRF. Amounts are in millimeters.

This is a 48 hour total precipitation forecast off the new 12z WRF. It shows 758.6 millimeters of rain that has fallen in southern Louisiana, dangerously close to New Orleans. If one does the calculations, 758.6 millimeters equates to 29.87 inches of rain in 48 hours. That is nothing to mess with, folks.

That's not the only solution printing heavy amounts of precipitation in short periods of time.

Here is the NAM 60 hour total precipitation forecast, also measured in millimeters. The white area shows 1000 millimeters and over. If we put 1000 millimeters to inches, we will find that 39.37 inches or more is predicted by the 12z NAM for the southern Louisiana area- something that cities without major levees would struggle to survive.

The Hydrometeorological Prediction Center (HPC) is being more conservative, with 16 inches predicted to fall over southeast Louisiana. Looking at other models, I find this to be on the low end. Here is my projection.

Andrew

Evacuations Recommended as Rainfall Forecasts Skyrocket

I, personally, am recommending evacuations across the New Orleans area as new rainfall data comes in.

These are two rainfall forecasts by short range models.
The top is the WRF-NMM, the bottom is the WRF-ARW. They are showing total precipitation at 75 hours on top and 72 hours on bottom.

The top image shows 1214 millimeters, or 47.8 inches of rain hitting the MS/AL border.

The bottom image shows 825 millimeters, or 32.48 inches of rain hitting New Orleans.

I am recommending evacuations at my own discretion, NOT from the NHC. Repeat, this is NOT AN OFFICIAL GOVERNMENT EVACUATION.

Andrew

Over 400 Earthquakes Hit Brawley, California

USGS 

Over 400 earthquakes hit the town of Brawley, California in the last seven days, many of which coming from the last 48 hours.

There were several earthquakes, the strongest of which measured approximately a 5.5 on the Richter scale. There have been no reports of severe damage or severe injuries, but small damage to household items has been reported (broken shelves, etc.).

If you are in an earthquake, quickly gather a prepared bag of emergency supplies and head outside to avoid possible falling debris from your house. Gas leaks and other dangerous broken pipelines can pose a serious threat to life.

Andrew

Isaac Running Out Of Time; Storm Surge A Real Threat

Isaac is running out of time as far as strengthening potential goes. He is at tropical storm strength at the moment, and has been for quite a while. Strengthening has been much slower than what had been anticipated, and this is already bumping down strength potentials for Isaac. Let's look at what Isaac looks like now.

Isaac has a very well developed western flank, with strong convection forming a neat eyewall and clear rotation evident within the structure. However, the right side of the storm is much weaker, with little to no reinforcement around Isaac's eye, and leaving the center of circulation practically open to the world.

Recent satellite looping indicates that Isaac continues to strengthen, but why has he not significantly strengthened as was expected?

This is a big part of it- Tropical Cyclone Heat Potential anomalies. When you have warmer colors on the map, that shows warmer waters are present and better for tropical cyclone formation and strengthening. However, where Isaac is now, he is in an area that is not exactly the best when it comes to supporting strong hurricanes. This, combined with persistent wind shear and dry air, has helped hamper Isaac's strengthening.

Latest models indicate the movement of Isaac into southeast Louisiana, right into New Orleans, as a hurricane. The latest model guidance shows a Category 1 hurricane making landfall on New Orleans, but the threat is far greater than that.

Isaac is, and has been, a very large storm. It has tropical storm force winds extending quite a ways from its center. What this brings me to is the concern of some heavy-duty storm surge. Take a look below at the storm surge forecast from the NHC.

This is a probability of storm surge above 10 feet. While the percentages are low, keep in mind that it is quite significant to even see a chance show up on here. Remember that New Orleans is barely above sea level, thus intensifying impacts even further than what those several hundred feet above sea level may think. Here is a forecast from the Ocean Prediction Center for storm surge.

This model from the OPC is indicating storm surge may go above 10 feet right up against New Orleans. This only continues to ignite concerns for a potentially major flooding event. Isaac is indeed large, so rainfall could be quite large as well.

I will keep you posted before, during, and after landfall.

Andrew