NYC Forecast: Slow warming trend this week

Cold weather has become a staple in the area forecast over the past several days, with the only warmup coming during a significant storm system — which produced the first rainfall of over 1″ since September in New York City. Otherwise, though, it has been a cold and dry pattern which has dominated the past several weeks. Some changes are in order during this week, but the start will be characterized by a slight warmup. Monday will be the first of a few “warmer” feeling days, with highs in the 40’s to near 50 in many spots as well as plenty of sun.

During the week, the airmass will slowly modify as a high pressure continues to control the pattern. High temperatures will reach into the upper 40’s and lower 50’s by the middle to second half of the work week. With the warmup, will come a chance of precipitation and the likelihood of clouds, which will move into the area as a warm front moves nears on Thursday.

NAM model, forecasting high temperatures in the upper 40’s to lower 50’s on Monday.

 Long range pattern could bring big changes

The longwave pattern throughout the Continental United States will become much more anomalous by the upcoming weekend. The first note of importance, in terms of our sensible weather, is that a frontal system may become lodged between a building Southeast US ridge and a large trough over the Western and Central United States. Although much remains uncertain at this juncture, it appears more unsettled weather could be in store during the long range period.

The main story in general, though, will be an anomalous trough and a tremendously cold airmass building into the Western and Central US. This cold airmass will eventually spill over towards the Great Lakes and New England — the extent of it still unknown. But forecast models are hinting at a potentially very cold airmass, with some disturbances sliding eastward through the Mississippi and Ohio Valleys which could theoretically produce some wintry precipitation.

Climate Prediction Center forecasting high confidence in below normal temperatures across the West and Central US during the 6 to 10 day period.

Although much of the forecast is speculation at this point, the building confidence in a significant intrusion of arctic air to the West and Central United States certainly marks the first step of a pattern change. It remains to be seen if the hemispheric changes progress eastward, or if the Southeast Ridge and lack of Atlantic blocking mitigate any potential wintry weather.