Good morning bloggers,
A storm system is tracking across southern Kansas this morning. This is the upper level storm that I am talking about and you can clearly see this on the infrared satellite picture this morning. Take a look:
The upper level low was near Dodge City, KS early this morning and this system will be tracking to near or just south of downtown Kansas City this afternoon. Here is a look at the 500 mb flow valid at 4 PM today:
As this system approaches some areas of rain and drizzle will be increasing and some heavier showers are likely along the path and near the path of the upper level low. After this system moves by the weather pattern continues to evolve. The cycling pattern is right now moving through the first cycle of this years pattern and it is still evolving. There are some important factors to consider. Let’s take a look at two of the influences that will be very important to monitor and track from week to week as winter approaches.
Influences On The Cycling Pattern:
Between now and Saturday a rather big vortex forms over northern Canada. There is no blocking at all and this is showing up on the AO and NAO indexes right now:
AO stands for Arctic Oscillation and NAO stands for North Atlantic Oscillation. When the AO and NAO are in the positive this will almost always indicate that there will be limited blocking to no blocking aloft and this can be a major influence on whether cold air can develop over the Arctic region and surge south. In an AO positive winter the chance of major Arctic air masses blasting deep to the south is much lower than during an AO and NAO negative winter. As you can see, the AO and NAO are trending positive and it shows up on the forecast 500 mb map valid on Saturday shown above.
This is a graphic we discussed in the past few winter forecasts. We must continue to monitor these indexes. An early season positive sign is not a good factor, but it is VERY EARLY in the season and we will be monitoring this daily and keeping you updated.
Where is ENSO going? ENSO stands for El Niño/Southern Oscillation. The recent forecasts over the past few weeks have been for a La Niña to develop and it very well may, but in the past two weeks the Niño 4 and 3.4 regions have warmed up. The 3.4 region, that is located near the central tropical Pacific Ocean, is the region most used to indicate whether or not it will be a La Niña or El Niño. This area has warmed from -.6°C to zero degrees Celsius in the past two weeks. This is a strong trend to neutral conditions, but most of the models still show a trend back to colder.
As you can see there is a lot to consider as we put together our winter forecast in the next six weeks. We must be patient. The pattern is just now beginning to set up. We will continue this discussion as we learn a lot more in the next few weeks.
What do these early indicators mean?
- An AO positive and NAO positive point in the warm winter direction. But will they stay positive?
- A neutral ENSO is neither here nor there on winter temperatures
- The cycling pattern is the most important factor to consider and we are just learning more in the next two to three critical weeks
Kansas City Weather Time-Line:
- Today: An increasing chance of rain with a nearly 100% chance rain begins falling by noon in most areas. Rain was already increasing at 8 AM as this storm system approached from the southwest. There will be a pretty nice breeze from the west and northwest at 10-20 mph. Temperatures in the 40s with wind chills in the 30s
- Tonight: Cloudy with rain ending early. Low: 42°
- Wednesday: Cloudy with some afternoon sunshine trying to break out. High: 59°
Have a great day and thank you for sharing in this Action Weather Blog experience featuring Weather2020 and the cycling pattern.