October 21, 2013 | 8:40 AM CDT - Another cold front is moving across the region today. As of the writing of this post, it is draped from South Central Oklahoma into Northwest Texas. It is expected to move through the Dallas-Ft. Worth metroplex around midday and through the Austin/San Antonio area late this afternoon.
8:00 AM SPC Mesoanalysis
While there are some showers occurring this morning, activity will be on the increase by early afternoon as the front encounters slightly better moisture and instability. Severe Weather is unlikely, but a few Strong Storms are possible this afternoon. The temperatures will not be that cold behind today’s front, and temperatures will rebound Tuesday. We should see a couple more fronts move into the area this week, aided by northwest flow aloft. As discussed on the Facebook page, moisture will be limited with each frontal passage. This means only low-end storm chances for most.
Looking at the extended, I believe there could be a change or shift in the weather pattern by early November. Right now, the NAO (North Atlantic Oscillation)is well into negative territory. With that said, it looks as though it has hit bottom and will trend upward over the next 7 days. By Halloween, the latest forecast shows it in positive territory.
CPC NAO (Observed & Forecast)
Generally speaking, when the NAO is negative it usually results in a trough across the Eastern US. When it is positive, it usually results in a ridge in the East. Here’s an excerpt from the CPC’s page:
“The positive phase of the NAO reflects below-normal heights and pressure across the high latitudes of the North Atlantic and above-normal heights and pressure over the central North Atlantic, the eastern United States and western Europe. The negative phase reflects an opposite pattern of height and pressure anomalies over these regions…Strong positive phases of the NAO tend to be associated with above-averagel temperatures in the eastern United States and across northern Europe and below-average temperatures in Greenland and oftentimes across southern Europe and the Middle East…Opposite patterns of temperature and precipitation anomalies are typically observed during strong negative phases of the NAO.“
The PNA (Pacific/North American Pattern) is, and will remain near, neutral over the next several days before trending down by early November. I believe this will result in troughs developing and/or digging farther west again with the gradual breakdown of the dominant Eastern US trough.
CPC PNA (Observed & Forecast)
I cannot say just how this will evolve, but it could mean a return to wetter conditions and maybe even some colder air. I’ll continue to keep an eye on how the weather will shape up around/after Halloween 2013. -Stay Tuned!