Below is a map showing the first 5 days of the month of February. When we did the last update we mentioned that persistence to the pattern was the key for that next ten day period. This indeed turned out to be the case as we had mentioned that the MJO was in unfavorable phases.
So lets look at the MJO so we can see where we are and then we can make a determination to where we are heading..
Latest current Observation shows us that the MJO is for the first time this season in Phase 7. However..phase 7 is still NOT a colder then normal weather pattern across the area as this chart below will show..
So it is no surprise that the pattern has been an above normal pattern so far. This pattern should continue for a couple days but THEN ..guidance is beginning to indicate another first for this winter season..
MJO guidance for the first time this season from the ECM & the GFES is suggesting that the MJO is going to go thru Phase 7 and propagate into Phase 8 & 1 & 2.
This is what the 500 mb level looks like in each of these phases for the month of February.
As the charts show above Phase 8 thru 2 would indicate below normal heights across the region. So the MJO looks as though it would be supportive of colder weather into the Mid Atlantic & the Northeast.
And we do see the models such as the ECM showing this happening today at 12 Z..
The ECM today drops the Polar Vortex into the Northeast and if this were to verify conditions would indeed end up getting colder..
However, we see by the end of the run the model starts to try and bring the Southeast Ridge back into the picture. Last run of the ECM (00z last night) showed warmer air in the extended..
So it seems as though there could be mixed signals occurring for the longer range. So this leads us to look at the teleconnections and see what is happening.
There is no question that the Pacific North American Oscillation is positive and basically looks to stay positive. This would be supportive of a trough across the east with ridging out west.
The North Atlantic Oscillation however..is positive and looks to stay positive thru out the forecasted time frame above , all but one member of the ensembles.
This is where things begin to get a little interesting because as noted above a Positive PNA indicates ridging along the west with a trough in the east but a positive NAO indicates that the coldest air would not be able to penetrate to the south..
So here comes the wild card..and this wildcard looks to be the deciding factor in whether the pattern can switch to a colder pattern and perhaps sustained or if it continues to me more or less + PNA transient shots of colder air in between over all warmer temperatures and that wild card is the Arctic Oscillation..
Why is it the wild card?
Well you can see there is two clusters in the ensembles or two groups of clusters. One group is taking the AO back to the positive side while the other group is keeping it negative..You can see this on the image below which is the exact same image but I drew two circles on the two clusters..
So the wildcard would be the AO and what happens with the AO. If the AO goes back positive ..then without a doubt with a + NAO , any cold shots would be transient in nature. If the AO stays negative then there is a higher chance of colder air becoming more sustained.. So that leaves us with one other teleconnection to look at and that is the EPO..
Eastern Pacific Oscillation is currently negative and looks to remain negative for about the next week. There after it goes positive and then later in the forecast period goes neutral positive.
Putting the pieces of the puzzle together it appears as though the next few days we should continue the above normal category in temperatures and then with the MJO heading into favorable phases we should take a step down in temperature category to a more seasonal temperature regime. This would cover the next week. Beyond that the signals become a bit murky but we can see a warm up again before perhaps stepping back down..So over all we think that persistence to the pattern is going to be key!
One final thought is that unless we get some WELL below normal temperatures to occur..the positive anomalies you see at the beginning of this month are going to be very hard to over come which gives the month of Feb a good shot at another month of winter coming in at above normal.
There also could be a shot at some snow in the 5 day period ahead…this shot right now does not look to be all that impressive.. but this would be around Saturday the 11th of the month..
We will continue to monitor and follow the latest and you can follow us on Facebook as well..
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