Nov 6, 2012 Noon Update

The science of weather forecasting is not perfect. Storms are not always certain to follow a specific solution even in the short range prior to a storm’s arrival; typically, the model guidance narrows a range of a storm down to a reasonable expectation within at least the 3 day range, allowing  for a high confidence forecast to be made, but in some cases, there continue to be differences within this range with lower confidence. This has happened in the past few years on numerous occasions, including the 12/26/10 blizzard and the 10/29/11 snowstorm. Typically, I take the conservative route to wait for more data, but sometimes I take a risk and make a forecast that’s bolder and which I think has the higher chance of being closer to reality.

In this case, the risk I took with the forecast backfired. The model guidance has had an extremely poor handling of this storm, and even now, less than 2 days away from the storm, still can’t get the set up right and continues to vary with the handling of the storm. After every model shifted east last night, the model guidance is back to being inconsistent, with most models shifting back west while some remain well to the east; while the models have had large short range trends as mentioned with the two examples in the top, there was already a growing model consensus 48 hours out; the models rarely change this much while within the 48 hour range as we are seeing with the current storm. As such, my latest forecast focuses less on the model guidance trends and more on the recent observations.

My preliminary forecast at this time, one which I do have a bit more confidence with than yesterday but still not a high confidence forecast, is for the low to end up closer to the coast but not as close as the discussion 2 days ago showed. Many of the points from that discussion will be brought back into tonight’s final forecast as well, which will include a longer discussion focusing on the observations of the storm, comparing them to today’s different model outlooks, and attempting to narrow the forecast down to a single scenario, clearing up the confusion from last night and earlier today.

With the latest thinking, coastal areas look to suffer the most, with strong wind gusts of 50 to 60 mph, perhaps higher in some areas, which along with coastal flooding will bring back many issues to the same places still devastated by Sandy which are struggling to recover. While the coastal flooding is not expected to be as significant as it was with Sandy, that region is already left more vulnerable to the impact of coastal flooding following Sandy.

The biggest change from Sunday’s forecast discussion, however, is the snow outlook. Heavy precipitation is expected to move into the eastern Mid Atlantic region, likely from Delaware into New Jersey, which along with marginal boundary layer and mid level temperatures, is likely to result in a band of moderate to heavy wet snow in places that typically do not receive snowstorms in early November, which in this case includes most of New Jersey, perhaps eastern Pennsylvania, into the NYC area and parts of southwestern New England. Even the Jersey shore and NYC may see some mixing with snow, although at this time very little, if any accumulations are expected in the coast. Snow accumulations are uncertain, but the potential is there for at least 2 to 5 inches of wet snow in the areas that fall under the heaviest snow in New Jersey.

Stay tuned for additional updates this afternoon and evening for the final forecast, and if any changes are to be made to the forecast above. Coastal areas are still highly recommended to pay close attention to this storm and the recent developments.


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