Let’s take a look at what factors will be playing into this severe weather threat. We’ll now take a look at the upper air flow for the same Wednesday evening timeframe as that CAPE image we just analyzed. Now that we see what will ignite this severe weather threat, let’s start checking out the forecasted severe weather parameters. It’s no coincidence that the highest instability values are forecasted within that risk area put out by the Storm Prediction Center, as well as lower, but still significant CAPE values to the east. However, as the last few frames will show you, the warm air mass has stagnated and flattened out on the northern edge, kind of retrograding back west into Europe. They have a set of mass who admire them. If you have the cash get an aspirated (internal fan) temperature shelter/enclosure. Shown above is an animation of temperature anomalies at the 10 millibar level.

The negative height anomalies in the Pacific Northwest and West Coast in general in the analog package are reciprocated in this model’s forecast, shown by the light blue contour on the west coast of North America. As we discussed in the analog package section, reds show above normal heights (high pressure) while blues show below normal height anomalies, which signifies low pressure. Again, my analogs showed this, and this will divert the storm track and active subtropical jet stream north through the Midwest and Ohio Valley (also shown in the first analog image). I outlined a section of slightly above normal AAM anomalies in the top half of this image to show that the jet stream could be enhanced here. The image above shows the predicted AAM anomalies on top, with latitudes shown on the left side of the image. This fits in nicely with my analogs, which show that high pressure area in the lefthand corner of the image.

In this forecast, a narrow band of high buoyancy stretches from the central Oklahoma/Texas border, almost due northward to central Kansas. Poor visibility due to fog, slower speed when running can effectively prevent falls and other accidents. If we look towards the latitudes, we see that the outlined portion falls between the 30N and 60N lines, which covers territory from the Mexico/US border to the midsection of Canada. The 30N-60N latitude area falls within the domain of the United States and into Canada, so that is where we want to look for the AAM anomalies. As we look up towards North America, we see above normal heights in the North Pacific towards (but not in) the Gulf of Alaska. We see an elongated stationary front extending from the northern Rockies into southern Kansas, central Missouri, and all the way to the Mid-Atlantic. Today, we see a 15% chance of severe weather within 25 miles of any given point over central Oklahoma, a sliver of north-central Texas, much of central and eastern Kansas, the majority of Missouri, and west-central Illinois. Looking into the United States, we see an area of above normal height anomalies in the Southeast.

You can often get a good idea of a person’s personality just by looking at their garden. This enhancement of the AAM comes along from April into the end of May, so that could be the time when we see some good severe weather in the nation. My point is this: I will say a kicker had a good week or bad week based purely on how many FGs and XPs he attempted. At this point in time, I’m remaining optimistic that this warm mass will propagate into the Arctic Circle and initiate a full-blown sudden stratospheric warming. Of course, severe weather can strike at any time, but a stronger jet stream can amplify chances for severe weather. Thus, when the NAO is negative, one can anticipate better chances for cold and storms in the East US, while the positive NAO brings about warmer weather. So, cold and wet favors mechanical weathering and hot and wet favors chemical weathering. The mass of warm air over the Arctic will result in high pressure winning its spot in that same domain, resulting in a pattern that favors cold air masses taking a shot at the United States. When there is high (low) pressure over Greenland, the NAO is said to be negative (positive).

As a result, low (high) pressure forms over the Eastern US, and the subtropical jet stream, which helps Nor’easters form, is strengthened (weakened). Mountains naturally force air higher into the atmosphere, and it is very easy for this air to be pushed high enough to reach the stratosphere, especially in the most significant northern hemisphere mountain range in the world, the Himalayas. The bottom part of the image shows the predicted AAM values from 4 separate CFS (the long range American model) ensembles. This is one of the more complicated and physics-based indices that I am watching these days, so I’ll just give a nutshell description of what the AAM can show. Higher CAPE values, in excess of 2000 joules per kilogram, can support thunderstorms at a severe level; values over 4000 joules per kilogram are considered uncommon, and can support explosive thunderstorm development. CAPE values indicate the ease of which warm air at the surface can rise and create thunderstorms. You can easily switch between detailed or compact layout to get weather information that is relevant for you.