Warmth Hangs Tough; Uncertainty Increases by SundaySeptember 30th, 2013 at 9:05 pm by Don Paul under 4 Warn Weather
There can be no doubt that temperatures will run well above average at least into Saturday. Despite the record deluge 2 Saturdays back, September rainfall is running a little below average for Buffalo as the month runs out, with 15 above average temperature days in the month. October will begin on a similar note, with at least a brief shakeup by Sunday or Monday as a better defined cold front crosses the region with some Showers & possible Tstorms. Even then, the ensemble means don’t establish any lasting deep trough over the Great Lakes which would allow sharply colder air to enter the picture. I should add, though, deterministic/operational models are in disarray by Sunday-Monday, with the GFS holding that cold front up until Monday in its latest run this evening. The European is faster, with a Sunday frontal passage. An observer familiar with operational models might be tempted to say, based on the past, “go with the European–it’s the best global model out there.” The European has been showing major inconsistencies from run to run, though, so there’s no auto pick here. All in all, there are no current signs of a fundamental pattern shift to a strong western ridge/eastern trough. The AO/NAO/PNA indices will be even less favorable by mid-October. And, the MJO will continue to be active for the next 2 weeks, propagating more to the east. That could have had a negative effect on cooling even while we had the negative AO/NAO.
The active MJO is probably one of the key factors in suppressing Atlantic basin tropical cyclone activity this past month. We’re up to “J”, the 10th letter in the alphabet. I have no time to look up the numbers, but I’ll venture a guess that this has been one of the least active Septembers on record, when September is normally a climatology peak period. October will begin in a similar vein, with the predicted active MJO and eastward propagation.