Sunday, March 22, 2015

Sunspot Numbers Plummeting, Stratosphere Warming

The number of sunspots has been anomalously low as of late, the lowest trend since roughly July 2014.

The above image shows sunspot numbers from NOAA over the past many months. Higher sunspot numbers (red) indicate that the sun is more active than usual. In the last couple of months, the number of sunspots has been dropping steadily from average values earlier in the year into 2014, interestingly enough in the midst of the strongest solar storm unleashed on the Earth in this solar cycle, per some reports.

What does this mean for our weather? The influence of the sun on our weather is still somewhat murky, but one big derivation we can make is that the stratosphere tends to cool down when the sun is active, and warm when the sun is quieter.

We are already seeing the stratosphere warm up, with more warming expecting in the future. The panels above show observed temperature values at different parts of the stratosphere in color, with the forecasted values in dashed lines. Notice how the ECMWF model expects the 10hPa level (top panel) to heat up notably, with a similar story in the 30hPa level (2nd panel from top). Although this warming won't be sustained, it's quite possible we see additional warming as the stratosphere exits its winter phase and enters its summer phase.

To summarize:

- Sunspot numbers have been steadily decreasing in the last few months, as we begin to end the current solar cycle.
- Stratospheric temperatures are responding by warming up, signaling and end to the winter phase.


March 24, 2015 Severe Weather Outlook

The Storm Prediction Center has issued a severe weather outlook for March 24th, 2015.

The Storm Prediction Center is expecting potential severe weather to develop in much of Missouri, northeast Oklahoma, northwest Arkansas, eastern Kansas, southern Iowa, and extreme western Illinois. The current risk is listed as a Slight Risk, which is not a significant threat outlook, but should be monitored.

WPC forecast, valid Wednesday, March 24th
The severe weather set-up will include a strong low pressure system moving into the Upper Midwest. A warm front well displaced from the severe weather outlook area (shown in Michigan and Ohio above) will allow for a narrow corridor of potentially severe weather to develop. These storms should develop along the cold front that will shift eastward through the area. But is this risk actually legitimate?

The above image shows projected radar reflectivity at 7 AM Central Time on Tuesday. We see a large complex of showers and thunderstorms moving across the corridor highlighted for severe weather on this day. This ongoing complex likely will hinder any severe weather prospects for later on in the day, which would end up ruining this severe weather chance. The best risk for severe weather is likely with that morning's band of showers and storms, portrayed in Missouri and southern Iowa on this NAM model forecast.

To summarize:

- Missouri, Iowa, Illinois, and Oklahoma are at risk for severe weather on March 24, 2015.
- This severe weather potential could be ruined by ongoing showers and storms early in the morning.