Mar 24, 2011: Snow Over, January-Like Cold Next

Yesterday's storm was an unusually difficult storm to forecast, with many uncertainties regarding precipitation types and amounts lasting even through when the storm was already affecting the area. The model performance for this storm was not a very good one, with the GFS busting way too far north, bringing mixing well into Connecticut, and the NAM model was too wet.

After I posted my final update last night, the storm in Pennsylvania continued to move east southeast and there was no indication that anything else would fall, however an unexpected round of snow quickly developed after midnight, bringing a widespread light to moderate snowfall to the NYC area, and with temperatures near or below freezing, accumulations were observed across the entire area, with even an inch of snow observed in Central Park. Further west towards northwestern New Jersey, the highest accumulations were observed, with as much as 10-11 inches in portions of Morris and Sussex counties.

As the storm exited the area, today brought partly cloudy skies with snow showers early, with high temperatures below the average for this time of the year, peaking in the lower to mid 40s across the area, resulting in the snow quickly melting across the central and eastern parts of the area. Despite no snow expected over the next week, the main story will be the January-like temperatures expected, with high temperatures failing to reach the 40 degree mark in parts of the area over the next few days.


Tomorrow's Outlook:

After cold temperatures tonight, which will get as low as the mid 10s inland and in the mid to upper 20s in NYC, tomorrow will bring mostly sunny skies to the area. High temperatures are expected to be similar to, if not slightly colder than today, peaking in the upper 30s to lower 40s inland and in the lower 40s for the rest of the area. A few mid 40s are expected for NYC and further southwest. A NW wind is expected.



Weekend Outlook: Cold Continues, Snow South Of NYC

The cold is expected to continue through the weekend across the region, with enough cold air and suppression that the next snowstorm will stay south of NYC and even mostly south of Philadelphia. Friday night will bring even colder temperatures than tonight, which may even get as low as the lower 10s inland with 10s possible as far as the immediate north/west suburbs of NYC. Saturday is expected to bring mostly sunny skies again with high temperatures slightly colder than those of tomorrow, peaking in the upper 30s to lower 40s across the area.

**Correction: The date on the map should say March 26-27, not March 24-26.**

By Saturday night, a quick moving system will move towards Arkansas and Tennessee, bringing a widespread area of light to moderate snow into the Ohio Valley. The snow, however, will be blocked from moving east and ENE into the area and will be forced to stay south. Unlike yesterday's storm, when there was still uncertainty on the storm's exact track and snow areas, it is certain with this storm that there will be suppression strong enough to keep the snow south of the Northeast. It is possible that it might trend a little north to bring some light snow to NYC, but most of the snow will stay to the south of NYC.


The NAM is likely overdoing the southern extent, showing a snowstorm for southern/central Virginia, and I went with a scenario closer to the GGEM and GFS, showing the highest snow accumulation potential from the West Virginia/western Virginia mountains where over 4 inches of snow are possible. Even towards Washington DC there is the potential for 1 to 3 inches of snow.

Other than a possible flurry south of NYC, Sunday will be mostly cloudy and dry for the area, with high temperatures in the upper 30s to lower 40s. Clearing skies are expected overnight but with much colder temperatures, similar to those of Friday night.

Next Week: Slowly Warming Up

As the storm exits the region, Monday will bring partly sunny skies to the area with a breezy NW wind expected. High temperatures will slightly warm up, peaking in the upper 30s to mid 40s across the area. Low temperatures on Monday night will be the warmest in days, likely staying above the 20 degree mark even in the interior parts of the area. Tuesday will bring temperatures above 40 degrees across the area, and may even get close to the 50 degree mark in the immediate NYC area which will be the warmest temperatures in the area since the most recent Tuesday two days ago but still below the average high temperatures for this time of the year. Temperatures will continue to rise afterwards ahead of a potentially more significant storm in the late week that may bring rain to the area, potentially bringing an end to this cold pattern. More information will be posted on the longer range as details become clearer.