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.

Nov 6, 2012 Morning Update

Nov 6, 2012 Morning Update

This is very unusual, and an unprecedented move on my part, but I had to remove my forecast discussion from last night. The model guidance is almost never this inconsistent - in the nearly 3 years I had this blog, and before that as well, the model guidance was never this inconsistent with an expected storm just 1-2 days prior to the event. After every single model trending and staying east last night, this morning's models are trending back west just as quickly.

Stay tuned for more information as I post additional updates on this frequently changing situation. An update will be posted at noon, focusing less on the model guidance and more on the observations.

Nov 5, 2012 Noon Update

5:00 PM: Confidence remains low on the forecast as some of the models that have been the most consistent with a significant nor'easter are backing down and shifting east, towards less impact in the region. The latest GFS run significantly changed from its previous runs and keeps the storm almost entirely east of NYC with less winds as well. Forecasts usually aren't this uncertain within the 2 day range ahead of an approaching storm - for now I kept the 5-day forecast similar, but slightly lowered probability of precipitation west of NYC. Tonight's forecast will be posted at 1:30 AM, following the rest of tonight's model runs, to have a better idea of what the storm might do. Stay tuned.

1:20 PM: Since yesterday's update, there have been significant changes with the model guidance regarding the nor'easter on Wednesday and Thursday. Some of the models are much more east, such as the NAM and UKMET, although they are likely outliers and are expected to trend back west. The CMC model has the storm intensifying much further south, with some snow in Virginia and Maryland along with moderate rain and strong wind gusts in the NYC area; the GFS and the 12z ECM, however, show a moderate wet snowstorm for the eastern Mid Atlantic up through eastern Pennsylvania and most of New Jersey, even including NYC.

Confidence in the forecast is currently lower than it was yesterday as the models continue to change around, with the main changes involving the precipitation type and the intensity, although wind gusts are still expected to be strong for the area, especially for the coast with wind gusts near or above 50-65 mph expected for Wednesday night into Thursday, which along with some coastal flooding will result in even more issues for the coastal areas struggling to recover from Sandy. Stay tuned for a detailed forecast discussion this evening reviewing today's trends along with a new, updated forecast.

Long Range Pattern Outlook #3

Brief Overview:

Tonight's long range pattern outlook focuses on the first half of November, regarding the medium range pattern and the warmer pattern developing, along with the November outlook. The final winter outlook will be posted towards late November.


Click below to read the full post.

Nov 4, 2012: Rain, Wind Return This Week

Forecast Highlights:

Colder temperatures will continue to affect the area over the next few days with highs in the 40s to low 50s and lows in the 20s to mid 30s, which will be an issue for areas without power and heating still struggling to recover from the devastating impact of hurricane Sandy. The dry conditions won't last for long, however, as a nor'easter affects the region on Wednesday into Thursday with additional rain, wind, and even snow for interior areas, with additional wind and coastal flooding for the coast. Click below to read the full post.

Nov 2, 2012: Nor'easter Expected Next Week

Forecast Highlights:

As the NYC area enters its fifth day after the devastating hurricane Sandy, the weather pattern offers little improvement over the next week. A sustained cold pattern will continue for the next several days, with highs in the 40s and lows in the 20s to mid 30s becoming an issue for places without power and heating. Following the cold, a nor'easter is expected to affect the region next week with additional rain, wind and snow, although not nearly to the extent of Sandy. Click below to read the full post.

Nov 1, 2012: Cold Weekend; Storm Possible Next Week

Forecast Highlights:

The devastating impacts from hurricane Sandy continue to affect the region three days since its landfall in New Jersey; although some places have regained power, many others still remain without power. Unfortunately, the upcoming weather pattern is not helping the hard hit areas from Sandy, as places without power will have to deal with a cold weekend with highs in the 40s to low 50s and lows in the 30s, which will additionally be followed by the potential for a storm next week. Click below to read the full post.