Raleigh Weather Discussion
Enjoy the warmth of today as temperatures should rebound nicely to near 70 before much colder air moves in for the balance of the forecast period.
It will be an unusually cold period with temperatures potentially averaging 10-15 degrees below normal.
We will likely see some isolated showers or snow flurries tomorrow night into early Thursday but it shouldn’t be a big deal and more of us than not will likely see no precip.
I am still watching this weekend to see if there will be any wintry weather chances. The trends in the models in the last 12 hours has been to consolidate the storm system into the Sunday through Monday morning time frame. Also the trend has been for the storm system to be a Miller B type system with a primary low over the Tennessee Valley and a secondary low forming near the NC/VA coast. For a significant winter storm in the Southeast to be possible we would likely need this to trend a little south with perhaps more of a Miller A type setup with one low along the Gulf Coast and a secondary potentially developing off the Southeast coast. The Euro has shown this scenario in some runs, but the latest 00z run trended north a bit and the 6z GFS trended south from the 00z run which was further north. Thus this now is in agreement with the 00z Canadian model of the primary over the TN Valley and a secondary forming off the NC/VA coast.
This scenario would result in less in the way of wintry precipitation south of Virginia although the NC Mountains and possible northern tier could still see some measurable wintry precipitation. Taken literally this would likely be a rain/snow mix for the Triangle changing to rain with no accumulation. However, this still has several days to play out in the model cycles, and although snow in late March is rare in NC, the anomalous –NAO/-AO pattern would support an extreme event, so stay tuned.
After this storm system passes, I think we dry out next week, but temperatures will remain well below normal through the period.
National Extended Weather Discussion
IT appears the extreme blocking will weaken some in the 11-15 day period. The Arctic Oscillation (AO) is forecast to rise to neutral or positive values while the NAO is forecast to remain negative however. There is some disagreement this morning between the global models on which way the EPO/PNA could go. The GFS Ensembles are showing a +EPO/-PNA pattern which would portend potential warmer, pacific air into the US, while the ECMWF/GGEM Ensembles show a –EPO/+PNA pattern developing which combined with the persistent –NAO would likely keep a cold pattern into early April. For now, I will side with the ECMWF/GGEM ENS combo.
The MJO has crossed into phase 8 and the latest GFS ENS forecast takes it into phase 1 and to phase 2 in about 15-20 days. Both phases support a –EPO, leading further support to the colder ECMWF/GGEM ENS combo. IF the pulse were to reach phase 3, the composites show a tendency for ridging across the southern tier of the US, so we could see a warmer pattern potentially by the 2nd week or so of April. The ECMWF Weeklies agree with this scenario with a warm pattern in place by the 2nd week of April. The CFS weeklies keep cooler weather around into the 2nd week of April.
I think we will see our cold pattern continue for the next 2-3 weeks, but I do think we may see the cold pattern finally end by mid-April.
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