Friday, January 20, 2012

Night has fallen, but Tornado Potentials Have Not

Compared to our earlier graphic, it may seem lower, but we are using a different equation to determine the tornado risk.
We are still seeing a tornado risk migrating from Alabama/Mississippi into Arkansas, North Mississippi and West Tennessee. We are also seeing strong storms moving along a frontal boundary which may produce some tornadic activity.
Make sure you are prepared for any emergencies that may strike.

Tornado Potential Rising in Mississippi, Alabama

Probability of a significant tornado
We are seeing tornado potentials spike this evening across the Southeast, particularly in Alabama and Mississippi, as a frontal boundary begins to push east and initiate thunderstorms. We advise you to make sure your emergency preparations are ready in the event of a tornado warning.
If you are under a tornado warning, hide in:
-Room in the center of the house
-Windowless room.

Stay safe.

Why I Think February Will Be A Wild Ride Coming Up at 3:00 PM CST Tomorrow

Snow Ramping Up in Chicago - Update 1

Radar 1 hour ago
Latest Radar
The snowstorm is ramping up, and has strengthened in the last hour as shown by radar images above. The system should continue strengthening and put down heavier snows as the day wears on.

Severe Weather Event (January 20, 2012)

Forecast Mesoscale Convective System (MCS) Index for 18 hours out
Higher MCS values indicate higher potential for strong storms
There is a potential for strong thunderstorms to put down some tornadoes or initiate some tornadic activity in west Tennessee this evening. Above we have the MCS index, which has values above 3 for parts of Kentucky and Tennessee. These values above 3 indicate a 'favorable' outlook for a mesoscale convective system (MCS) to form.
This is basically a forecast for tornadoes 15 hours out. We can see elevated levels of tornado potentials in West Tennessee that will be caused by a frontal system associated with the snowstorm the Midwest is receiving.

Chance of a tornado: 50-60%
Where a tornado is most likely: Jackson, Tennessee
Confidence a tornado will touch down: Moderate

While it is hard to forecast for tornadoes, this does have potential to be a tornadic situation, as it is uncommon to see the Tornado Mask map above have color on it.
Stay safe, everyone.

Significant Snowstorm (1/20/12)- Initial Briefing

700mb frontogenesis
We are seeing increased areas of frontogenesis across Iowa and parts of Northeast Illinois at this hour. What frontogenesis signifies is the forming of a frontal boundary of sorts. It is somewhat complicated, but in this event the bottom line is that areas with increased frontogenesis are going to get more snow out of this system. Again, we are seeing values of frontogenesis (FTG) rise in Iowa and Illinois. We can compare that with radar below.
Radar is indicating that the heaviest snow is over eastern Iowa. Based on that, it is estimated that snow will begin falling in Chicago between 10:20 and 11:30 AM CST. Depending on what factors are taken into account, these times may be shortened or lengthened.

We will have updates throughout the day on this system.
Because this is a nowcasting (forecasting as it happens) event, we will not be making a new graphic. However, the models did win in the NWS vs Models fiasco last night, so our graphic from yesterday is valid once again.