3/22 All Zones AM Update: Cold Shot, Then Slow Warming Trend into Saturday

Good morning! A roller coaster ride of temperatures is on the way over the next several days. It begins today, with a strong cold front moving through the region this morning. Gusty northwest winds have already begun, and even despite plenty of sunshine temperatures have fallen into the upper 20’s to lower to middle 30’s across the area this morning. A slow climb back into the middle and upper 30’s is expected this afternoon, but blustery winds will continue.

Much of those winds will be aided by a tight pressure gradient between a low pressure in the Canadian Maritimes and a high pressure surging into the Great Lakes. We anticipate winds continuing to gust between 40 and 50 mph this afternoon, with wind chill values in the teens and lower 20’s for the majority of the day. High pressure builds closer to the region tonight and winds will begin to diminish. Temperatures, however, will fall additionally as ideal radiational cooling conditions occur with clear skies and lighter winds.

High pressure will be over the region on Thursday, supporting mostly sunny skies once again. The airmass will begin to modify a bit to its surroundings, and mid level atmospheric heights will begin to rise. As a result, temperatures during the afternoon may rise into the upper 30’s and lower 40’s. High clouds increase late in the day as a warm front makes its approach.

NAM showing sleet/freezing rain possible over inland areas with precipitation arriving Friday AM

NAM model showing snow/sleet/freezing rain possible over inland areas with precipitation arriving Friday morning

Stronger mid-level ridging builds into the region on Friday. High pressure moving off the Mid-Atlantic coast allow the flow to turn more southwesterly, with warmer temperatures in the upper 40’s and lower 50’s by Friday afternoon. A warm front moving near the region and mid level shortwave energy will keep some cloud cover around, with the potential for some showers or even a wintry mix in the higher elevations during the morning hours.

On Saturday, the latest guidance indicates the warm front will  lift far enough north for milder temperatures with more sunshine mixing with some clouds. Highs will likely reach the upper 50s to middle 60s much over the region — perhaps even approaching 70 over Southern and Central NJ. A tight pressure gradient will exist to our north as a cold high pressure over New England fights the approaching warm air — leading to the cold temperatures over New England and very warm temperatures in the Mid Atlantic.

The latest ECMWF showing warmer temperatures over region, but colder temperatures further north.

The latest ECMWF showing warmer temperatures over region, but colder temperatures further north.

Finally, low pressure will track into the Ohio Valley/Great Lakes on Sunday and Monday. Mid-level shortwave energy with this disturbance will be shearing out as it hits a confluence zone over New England. The low pressure area will weaken and transfer off the Mid Atlantic Coast. This will lead to plenty of warm air in the mid levels — so no snow threat is anticipated. But cold air near the surface may allow for some wintry mix to occur with sleet or ice in the interior, especially in PA, Southeast NY, Northern NJ and New England. The city and areas near the coast are expected to remain all rain.

This system will exit the region with more clearing expected by Monday night. Temperatures may warm up again later next week if ridging builds into the Northeast US as some models indicate. But an active pacific jet could keep weather conditions more unsettled over the entire region. Stay tuned for zone forecast updates on weather through this weekend and early next week.