Jan 22, 2012: Freezing Rain Tonight

After yesterday’s snowstorm, which dumped anywhere from 3 inches to as much as 12 inches in parts of southern Connecticut, mostly cloudy skies were observed today with temperatures reaching the upper 20s inland and the lower 30s across the rest of the area. A low pressure moving into the Great Lakes region will bring warmer temperatures, but not before resulting in widespread freezing drizzle across the area tonight resulting in light ice accumulations in the interior parts of the area. The storm, however, will end the temporarily colder conditions across the region, with above to well above average temperatures returning for this week.

Tomorrow’s Outlook:

Freezing drizzle will continue tonight north and west of NYC, changing over to rain in the immediate north/west suburbs later tonight and in the northwestern parts of the area by Monday morning, resulting in hazardous traveling conditions. With a much warmer air mass aloft, however, temperatures will quickly warm up tomorrow, reaching the mid to upper 40s across the area for highs with parts of the area reaching the lower 50s. A cold front will move through in the evening, bringing a line of scattered showers, with some of these showers potentially including locally heavy rain and/or gusty winds.

Tuesday – Friday: Back To Mild, Rainy Weather

In the Long Range Outlooks section, back on January 14th I mentioned the potential for a warmer pattern between January 20 and 28. Due to yesterday’s snowstorm, which was unexpected at that time, the first part of that time frame, January 20-22, ended up colder than average. The intensity of the warmth has been scaled down from the original potential, although starting tomorrow, the next 7 days will bring warmer to much warmer than average temperatures across the region, passing the 50 degree mark twice in the area and the 60 degree mark once in the southern Mid Atlantic. These temperatures are not uncommon in the winter, although they typically last for only a short amount of time, while this winter had temperatures this warm last for longer periods of time while ending up much more frequent than average; in fact, almost half of December had high temperatures near or above 50 degrees, which is much warmer than average.

Behind Monday night’s cold front, temperatures by Tuesday morning will still be significant warmer than average. Average low temperatures for this time of the year are in the 20s; low temperatures on Monday night will drop into the mid 30s to lower 40s across the area. The colder air mass coming in behind the front is very weak, and as a result temperatures on Tuesday will warm up into the upper 40s to lower 50s inland and the lower 50s across the rest of the area. Slightly cooler temperatures are expected for Wednesday with mostly sunny skies and highs reaching the mid 40s across most of the area.

By Thursday, a weak storm is expected to affect the region, although details are still uncertain. The ECM and CMC models show little precipitation, while the earlier GFS runs showed more widespread light rain across the area. Cold air is marginal in this time frame, so any precipitation that falls will likely be in the form of rain across the area with perhaps some frozen precipitation falling at some point further inland. The latest GFS run, however, had a stronger storm for Thursday, and while such a scenario is not impossible, for now given the stronger model consensus arguing otherwise, I am considering the 18z GFS run as an outlier. At this time, I am expecting scattered showers across the area with highs in the lower to mid 40s, although the forecast is subject to some changes.

Next Weekend: Another Storm Potential?

There is increasing uncertainty with the models regarding a cutoff low in the southern US in the second half of next week that will bring heavy rain into the southern US, specifically over Texas. This cutoff could phase on Thursday with the Thursday storm becoming the bigger one, as the 18z GFS suggested, although for now this is less likely. Going by the more likely solution of the cutoff low phasing on Saturday, however, a bigger storm potential could be there. Should the cutoff low phase on Saturday, the models that show this, the ECM and GFS, currently have a coastal low, with the 12z ECM showing a significant snowstorm for the interior parts of the area with the GFS keeping the storm mostly offshore. There is still more time for the storm’s track to change, should there be one on Saturday, although if phasing does place, given the pattern in place that is the same as the one that’s been in place since November, the tendency of cutoff lows in the southern US to phase too far west for the area to see a snowstorm, and the lack of a strong cold air mass in place, I am thinking at this time that an inland storm track would be more likely than a coastal snowstorm. There is time left for changes though, it is possible that there may not be a storm in the weekend, but if there is one, at least as of now a snowstorm does not appear to be very likely given the set up. Stay tuned for more information on the weekend storm potential.

Long Range: Looking Into February

Looking beyond the weekend, some models attempt to bring changes in the pattern; the GFS has been attempting to drop large cold into the US over the last 3 days. The GFS model has attempted to show the pattern changing since the start of December in its longer range, and each attempt failed as the pattern remained in place. Over the last week, there was a temporary interruption in the pattern as strong ridging developed near western Alaska and the polar vortex dropped into southern/central Canada, but as I have mentioned earlier this month when these changes became apparent for the longer range, they were likely to exit just as quickly, and the pattern is already returning back to where it was until now, with a positive NAO/AO, no blocking, an overall progressive pattern and the strong cold air trapped in Canada and Alaska. The MJO is still stuck in phases 4-6 as it has been for most of the last month, a signal that the pattern is still solidly in place as the MJO is still unable to move into phases 8+1, favorable for cold in the eastern US.

With the previously mentioned signals, February is likely on track to be once again near average to warmer than average. Despite this, however, more signals are also pointing to slightly more cold and snow in the region in February and/or March than what the region has seen so far this winter. Having some more cold and snow in February would not be very hard to achieve considering that December ended up nearly 6 degrees warmer than average without any snow in Central Park, and January is on track to end up noticeably warmer than average with only one, potentially two at most, accumulating snow events in Central Park for the entire month. The latest models are already signaling that the EPO may drop towards negative with a slightly rising PNA, although the NAO and AO remain mostly neutral to slightly positive, which although potentially favors slightly better cold/snow chances for the region and isn’t a set up for significant warmth, also isn’t one for significant cold and snow. At this time, I am looking towards the first 10 days of February for the next potential accumulating snow event for the NYC area; while it is not guaranteed that the area will see accumulating snow at the start of February, it is a possibility, especially if there are some changes in the pattern including a neutral/slightly negative EPO towards slightly more sustained cold in the region. While snow in February and March is not expected to be enough to make the winter snowier than average, it is likely to add to the current winter totals and bring the area’s snow totals closer to the average. Stay tuned for more long range updates on the pattern.

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