Jan 22, 2011: Update On Wednesday's Storm

***This post is from 2011. Please visit the MAIN PAGE to see the latest forecasts for January 2012.

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Note:

Below are the results for the poll that was active for how yesterday's storm (Friday, Jan 21) would affect the area:

0 votes - Weak storm, snow south of NYC
8 votes - Storm clips NYC with light snow
16 votes - Big storm, heavy snow in NYC
4 votes - Big storm too close to coast, rain/snow mix

A poll remains open for Wednesday's storm effect on the area. Please vote your thoughts in the poll, which will close on Tuesday morning.

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As an arctic air mass moved into the region, today brought much colder temperatures for the area, with high temperatures only in the lower to mid 20s across the area. Temperatures this morning were very cold, getting as low as -5 degrees in Sussex, NJ!

Tonight's temperatures have already dropped below the expectation, already below zero in interior areas, and as a result I have lowered forecast low temperatures for tonight, now expected to be between -8 and -2 degres inland, lower to upper 0s for the north/west suburbs of NYC and southern Connecticut, and lower to potentially mid 10s in NYC.

Tomorrow will be slightly warmer than today, bringing high temperatures in the lower to mid 20s across the area. Tomorrow night will bring temperatures similar to, if not even colder than those of tonight, and as a result Monday will be a very cold day, with high temperatures only in the mid to upper 10s across the area and a few lower 20s possible near/south of NYC. Afterwards, however, the cold will weaken as a storm approaches the area, bringing rain and snow to the area.


Wednesday's Storm: Big Storm, But Not A Big Snowstorm?

In my update yesterday, I mentioned how some models were further west with the storm and others were east, and while I went with the western solutions, I did not rule out the possibility that solutions further east verify. Today's models continue to be variable, however there continues to be evidence suggesting that this storm may end up hugging the coast or tracking inland, bringing more of a wintry mix and/or rain event for the area rather than yet another big snowstorm.


Model Analysis: Today's models have been more variable, however we have seen some interesting trends, especially with the GFS model. The GFS had difficulties handling this storm this morning, showing completely different solutions than most models with snow staying even to the south of the area, and while its 12z run has made corrections, showing a Miller A type of storm, or a low coming up the East Coast, it still has more trending to go through. Its 18z run did show a slight westward trend, though it remains one of the easternmost solutions for this storm, and I am expecting the GFS to continue trending west at this time, though how far west it trends is uncertain.

The GGEM model remains consistent with the idea of some snow/mix changing over to rain, heavy at times, for the area, though it hasn't been very consistent with the timing and location of the storm, with its 12z run being much slower, further southwest, and stronger. While its 12z run may be too slow and perhaps too warm, which are some biases that the GGEM has in some cases, such a westward solution cannot be completely ruled out yet. The ECMWF model continues to take the storm close to the coast, apparently with mixing issues for the area, and the NAM model, which started to come into range today, went with a west track closer to that of the GGEM, however this is still the NAM's longer range when its accuracy is not as good as when compared to its medium/short range, and it is expected to change at least several more times before becoming more consistent.

While this storm does have the potential to be a significant snowstorm for the area, the pattern is not as favorable as it could have been, especially with a high pressure to the north of the storm moving east quickly and a lack of blocking. We are also missing strong cold air with this storm, something that has been in place with almost every significant winter storm this winter. The majority of the model and model trends today suggest that the storm may track near the coast or inland, however there is still a spread with how each model handles the storm. At this time, I am going for a solution east of the GGEM/NAM but west of the GFS, though this is still subject to change, and it is possible that the models may trend west towards the GGEM/NAM with a big rainstorm, or the GGEM/NAM could trend east with a snowstorm for the area.


Current Thoughts For NYC Area: There does appear to be cold air when the storm starts, meaning that the storm may start with at least some wintry precipitation, however some models bring more snow to start, while others such as the 12z GGEM have only a little front end snow/mix followed by a heavy rain event. Based on the solution I previously described I am leaning towards, the storm will start on Tuesday night with precipitation possibly in the form of snow or a wintry mix, with temperatures warming up. By Wednesday, I am thinking at this time that places near and east of NYC may change over to rain, with a wintry mix further inland, potentially rain if the warmer case scenario verifies. Regardless of precipitation type, it appears that precipitation has the potential to be heavy, and I mentioned potentially heavy precipitation in the 5-Day Forecast.

The scenario described above is only my thinking at this time, and the exact precipitation type is still a relatively low confidence forecast. It is possible that may see a further west scenario, with a little snow/mix to start followed by heavy rain, or we may see a further east scenario with mostly snow for the area. Regardless of the uncertainty, this has the potential to be a major storm in the East Coast, and needs to be watched closely for impacts ranging from heavy snowfall to significant flooding. Stay tuned for more information on this storm.