First off, a weak frontal system will bring less than half an inch of rain to our area tomorrow. Behind it, cool air follow. High temps. on Saturday will not get out of the 60's. Temp departures from normal will be 7 to 10 degrees below average.
At the 500mb level early next week, a ridge moving from west to east across the U.S. will collapse on top of upper air energy located in the southeast. The newly formed upper level low will meander in the southeast for a couple of days before being picked up by another piece of upper energy ejecting out of south-central Canada. The GFS on Sunday night has the upper low over SC with the second piece of energy getting ready to enter the U.S. in the upper Midwest.
The GEFS do not have much of a phase between the two upper air entities. The ridge spike in the west helps make it interesting, but the general flow across the U.S. is progressive. The NAO is positive and the EPO is neutral to positive. The trough lifts quickly northeast and the pattern goes back to being transient under the progressive flow.
The EPS are more robust. They to have the partial phase between both pieces of energy, however the ridge spike in the west turns into a sustained +PNA/-EPO thanks to an anomalous trough over the Aleutians.
Instead of the eastern trough lifting out it decides to stay over eastern Canada and the U.S. If the EURO is correct, we would remain on the cooler side of the pattern for all of next week and possibly into the 3rd week of October.
This is quite a contrast between both models considering we're only looking 1 week out. Perhaps the MJO can offer some insight to how the upper air pattern will actually play out.
The GEFS take the MJO through phases 8 then 1.
The EURO stays in the COD then pulses into phase 1.
OLR anomalies shows some activity near the Dateline that should propagate east into MJO regions 8 then 1 over the next several days. In my opinion, the MJO signal is not strong enough to suggest it will have a deep impact on our pattern. I think we'll see these graphs trend weaker over the next couple of days.
At this point I think it is best to continue monitoring the trends the next couple of days to see if either model tips its cap toward the other. The EURO (left) is very impressive with the western and Arctic ridges connecting to bring a block. The GFS (right) insists we'll stay progressive with no western ridging. The key will be the Aleutian trough, which both models show in the 8-10 day range. Therefore, if I had to choose which model I think is better handling the pattern I am inclined to say the EURO.
Summary
1. Temps in the 60's this Saturday.
2. Storm signal on Tuesday the 13th though likely to stay either to our north or east.
3. Cool down between 13th and 15th, but how long will it last?
4. Watching the tropics for one last possible system that could effect the U.S. the end of October.
5. Remember by 2015-2016 Winter Outlook will be released on November 1st.
Enjoy your night!
-Francesco Paparatto
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