Feb 13, 2012: Rain On Thursday; Still Mild

Forecast Highlights:


- Warmer week ahead; 50+ degrees Wednesday
- Rain returns for Thursday afternoon/evening
- Chilly and dry weekend; snowstorm likely to stay south


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With a high pressure moving into the region, today brought drier conditions along with mostly sunny skies. Temperatures were chilly today but still at least 2-4 degrees warmer than average, peaking in the mid 40s across the area. The radar posted to the left shows that isolated light precipitation is moving into West Virginia; this precipitation is associated with a widespread yet weak and dry system that will move into the area tomorrow, bringing mainly cloudy skies along with an isolated rain or snow shower at times, especially in the evening and overnight hours.

Temperatures once again will stay warmer than average through the week, reaching the 50s in most of the area on Wednesday and possibly in some places again on Friday. The next storm will move into the area on Thursday, and while there may be a bit of cold air initially to result in a brief period of snow/sleet inland, rain will be the primary precipitation type. Chilly temperatures will return again for the weekend, although the next snow potential once again appears likely to focus to the south of the area.


Tomorrow's Outlook:


With the weak storm moving into the region, clouds will increase tonight, and mostly cloudy skies are expected tomorrow transitioning to cloudy skies by the afternoon. Temperatures will be slightly warmer than those of today, reaching the lower to mid 40s inland and the mid 40s across the rest of the area, along with a SSW wind expected. Isolated rain/snow showers are possible, especially in the evening and overnight hours, but no snow accumulation is expected.


Wednesday - Friday: Mild, Rainy At Times


The storm will mostly move out by Wednesday, although isolated rain/snow showers are still possible in the morning. Partly cloudy skies are expected by the late afternoon with warmer temperatures, reaching the upper 40s to lower 50s across the area. In the warmer case scenario, temperatures may approach 53-55 degrees close to NYC.

By Thursday, the next storm will approach the region, although this storm will be stronger than tomorrow's weak event. The latest trend on the models has been towards more suppression of the storm, with the primary low staying in the Ohio Valley instead of moving way north into the Great Lakes. A transfer to a secondary low pressure further southeast will take place with this set up, and the transfer is becoming more likely to take place further south. The latest NAM run has most of the precipitation falling with temperatures at 850mb below freezing, although this does not signal a snow event in this case; 925mb temperatures closer to the surface are very marginal, only near freezing in NYC and slightly below freezing inland, and surface temperatures are still in the 40s in NYC and in the 30s inland. As a result, I kept the precipitation type as rain for the immediate NYC area (NYC and its north/west suburbs) and further east, while adding a risk of snow and sleet around noon on Thursday. In the colder case scenario, the storm may start out with a brief period of snow and/or sleet all the way down to the immediate north/west suburbs of NYC. The rain will otherwise intensify by the afternoon and evening hours, ending towards midnight with at least 1/4 to 1/2 inch of rain expected. Partly sunny skies will return by Friday with breezy conditions possible and temperatures peaking in the mid to upper 40s across the area.


Next Weekend: Chilly; Storm Likely To Stay South


As mentioned since late January, the recent western US ridge signaled that the pattern across North America has changed. The polar vortex has been displaced over southeastern Canada for the longest time so far this winter, and once it retreats back north over the next couple of days, it is expected to stay out of Greenland and Alaska, where it has been stuck over the last couple of months resulting in a mild pattern with very little snow for the region. Although the recent pattern change still favors warmer than average temperatures and not many snow chances, there are some minor changes that slightly increase the potential for a snow event for parts of the region around next weekend. The late week storm will move towards Newfoundland, but will be unable to move quickly into Greenland as weak ridging will develop west of Greenland, a factor that is often observed during snowstorms south of the Northeast. With the trough in place, there is also likely to be an initial cold air mass in place. The main issue at this time is the western US, as little ridging is expected, making the set up less amplified and any storm more likely to move offshore rather than straight up the coast. Most of today's models reflected this with a rain/snow event for North Carolina and the southern Mid Atlantic, although the 18z GFS run took the storm further north, with light rain/snow in parts of the Northeast. There is still a lot of uncertainty with this set up, but at least at this time it is likely that the weekend storm should stay to the south of the area, with otherwise chilly temperatures along with low temperatures in the 20s and highs in the 30s. Temperatures are expected to warm up again by early next week back into the 40s. Stay tuned for more information on the outlook for next weekend.