Sunday, September 26, 2010

October 2010 Forecast/Discussion

Telleconnection Discussion/Forecast

NAO:The NAO has been averaging Slightly Negative [~-0.4] since June, what this means is that while we have had major heat over the Summer, the NAO has actually been Negative, which is likely due to a lower/negative correlation with Temperatures in Summer. Where are we going?
NAO looks to hang around Neutral over the next several weeks, with any possible direction after that being a decent possibility;Hence I am going for a overall NEUTRAL NAO for October 2010.

PNA:The PNA has been averaging Slightly Positive [~0.4] since June, which is unique in a way that since we got we are in a La Nina/-PDO phase, the PNA has a high correlation to the PDO. The PNA over the last couple of days has went negative for the first time in almost 2 months. Where are we going?

There are mixed signals on where the PNA may go, even though the GFS wants to bring it positive, -ENSO/-PDO combo goes against a +PNA;Hence I am going for a overall NEUTRAL PNA for October 2010.

ENSO:At the moment, the ENSO state is ~at Moderate Nina levels, though readings are showing Strong Nina values, and it is Central-Based/Basin-Wide at the current time. I would say October '10 analogs are;54, 64, 70, 73, 88, 98, 07

This shows a Slight Warm tendency especially in the Midwest/Northeast, and a Slightly Wet tendency over the OV. Although the years by themselves could be a lot different.

Temperature Discussion/Forecast

SE Ridge tendency comes in to play regardless of near neutral NAO/PNA, also a possible SW ridge. North is overall cold with Cold Fronts briging in short periods of very cold air, though they wont have the effect of the SE Ridge, which is the reason they will average Below Normal. I think that the Below normal anomalies in the North may suprise some, I think there is a day or two where these areas dont get above 45, maybe even 40, these areas will also have occasional Frost/Freezes because of this.

Precipitation Discussion/Forecast

Below normal precipitation will take place across the South due to a Weak/Nonexistent STJ and a SE Ridge, though isolated locations could be Average or Above Average in the Aformentined areas due to possible Thunderstorm action or possible Tropical action. The North will have Above average precipitation due to a Dominent/Strong PJ, this will spin up lots of systems, some will be cross country travelers, Canada systems, and possibly a GLC or an AR for the Northeast.

And for Shits and giggles, Wintry potential
Forecast Confidence:7/10

Comments would be appreciated :)

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