Atmosphere May Be Showing El Nino Signs in Precipitation Placement

The latest GEM 144 hour accumulated precipitation forecasts displays a very El Nino-like pattern, with little precipitation in the Midwest and a lot of wet weather on the East Coast.

As is typical in El Ninos, precipitation is favored over the East Coast into the Gulf of Mexico coast, with little precipitation over the Ohio Valley and Midwest. The image above very well shows the pattern described, with a wet pattern holding out over the East Coast. But is the atmosphere showing an El Nino in other indices?

The Southern Oscillation Index, or SOI, is rapidly dropping, characterizing an El Nino pattern. El Ninos are detected when the SOI is below -8, and as shown above, the SOI is below -10.
BUT!
A look at the 30 day average of the SOI, used in the graph above, shows that the 30 day average has shot up to a value of positive 2. Positive values above 8 indicate a La Nina. This is fairly confusing for the atmosphere, because sea surface temperatures are positive, while the SOI is in fairly neutral territory. This will become interesting to monitor as we progress into the fall months to see if the atmosphere can sort itself out.

So while the precipitation appears to support an El Nino pattern, the SOI is in disagreement, and it will likely take a good month to see the SOI sort itself out.

Andrew

Derecho Potential Video Briefing

Apologies for the bad sound quality, a nasty cold I have adds to the distortion thanks to the video itself.

Severe Storms Initiate in Northeast

There is a severe thunderstorm watch over parts of the Northeast and Ohio Valley, as strong to severe thunderstorms quickly get going in the mentioned regions.

It is very possible that this line could form more storms to the southwest, and these storms could produce a derecho based on the derecho composite values seen below.

This could become a very violent situation in a very short amount of time should storms form in the southern Ohio/West Virginia area. This entire situation will need a lot of monitoring for the rest of the day, and I will be closely watching storm development through the day.

Andrew

Moderate Risk Issued for Michigan

A short term moderate risk has been issued for Michigan as strong to severe thunderstorms fire in the region and move south.
Water vapor imagery clearly shows the sudden development of new strong thunderstorms, and the threat is expected to grow as the storms enter an area favorable for damaging winds.

Andrew

Significant Damaging Wind Possible Tomorrow in Northeast

There is the potential for significant damaging wind tomorrow in the Northeast, leading the Storm Prediction Center to include a moderate risk for much of the area I outlined in pink.

The latest NAM model is projecting strong to severe thunderstorms to fire along an advancing cold front in the Northeast and Ohio Valley tomorrow. This cold front appears to ignite a long stretch of several strong to severe thunderstorm clusters along the mentioned regions. 850mb winds will be pushing 35 knots, signaling the atmosphere's willingness to get something going, particularly severe thunderstorms. Additionally, as much as 4000 j/kg of instability may be present to support the storms, which appear to want to fire in the afternoon hours into evening.

This situation is being closely monitored at The Weather Centre, and a Storm Action Day (SAD) is going to be called tomorrow.

Andrew