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Wednesday Briefing: Warmer, Unsettled Thru Friday, Northeast Winter Storm Saturday Night

Good afternoon! A return southerly flow with high pressure sliding offshore, is helping temperatures rise into the upper 40s to around 50 this afternoon. Some clouds will be mixing with or filter sunshine. But overall it will be a pleasant afternoon for the middle of February.

It will become mostly cloudy quickly this evening, as upper-level disturbance and a warm front approach from the west. Some rain showers are likely later this evening and overnight. Some briefly moderate to heavy downpours are possible. But this will be moving fast enough, that we don’t anticipate enough rainfall to cause any serious flooding issues. Temperatures will likely remain mostly in the 40s over the region overnight with warm-air advection and cloud cover.

HRRR showing rain showers over the parts of PA,New Jersey, and Southeast NY and CT tonight

HRRR showing rain showers over the parts of PA,New Jersey, and Southeast NY and CT tonight

For Thursday, any linger showers should taper off early in the day. Then clouds may break some limited sunshine during the day. A deeper southwesterly flow will allow for temperatures to climb into the upper 50s to middle 60s. Some areas along the south-facing shores of Long Island and Connecticut may ay be a bit cooler with winds coming off the cooler ocean or sound waters. But overall it’s looking like an unseasonable mild for much the Northeast.

ECMWF model showing high temperatures in 60s for over parts of PA,NJ and the Mid-Atlantic on Thursday

ECMWF model showing unseasonably mild high temperatures for over parts of PA,NJ and the Mid-Atlantic on Thursday

More clouds and rain showers are likely Thursday night and Friday, as a strong cold front moves through Northeast. Temperatures ahead of this cold will still be mild with highs on Friday likely in mid-upper 50s. Colder will begin rushing as the cold moves through late Friday afternoon and evening. Canadian high pressure will briefly builds into Northeast later Friday night into Saturday with temperatures closer to seasonable cold levels.

Clouds will begin increasing later Saturday afternoon as next storm system approaches. Models could continue show a shortwave trough amplifying as it approaches the Northeast US. This results in area of low pressure over the Lower Mid-Atlantic region by Saturday night into Sunday. There is still some uncertainty on the track and intensity of this low, with some various models solutions in progressive pattern with a lack of high-latitude blocking.  However, a strong upper-level streak to north may enhance more precipitation farther north of the low track. There is a chance that snow could become moderate to heavy at times, with some moderate to signficant snowfall accumulation over parts of Northern Mid-Atlantic region and into Southern New England. during the Saturday night.

 

ECMWF models showing snow in parts of Northeast with a wave of low pressure to the south Saturday night

12z ECMWF today model showing snow in parts of Northeast with a wave of low pressure to the south Saturday night

That being said, high pressure will be off the coast by Saturday night. That will initially cause south-southeast winds with a warmer ocean influence. As a result, precipitation might be more of wintry mix of snow, sleet and rain along the I-95 corridor and coastal sections. Until some colder air returns, with winds becoming northerly and changing precipitation to all snow before ending on Sunday morning. If there is too much mixing, or surface temperatures are too warm this will lead to, some reduced snowfall accumulations. Further inland, especially over the higher elevations temperatures, these are should remain cold enough for mostly snowfall, as the long the storm track remains south. There is better chance of for several inches of snowfall. But we will be fine tuning these details as the storm draws closer.

After this storm moves away later on Sunday, a major warm up is likely to begin on Monday and Tuesday. Western US troughiness will likely lead to very strong Southeast Ridge with a deep southwest flow. Temperatures could be well into 60s and perhaps into the lower 70s during the week. But we still anticipate  strong -NAO block to retrograde into Greenland/Davis Strait to flatten the the Southeast Ridge, at the end of the month. So we expected more colder, active pattern to return the Northeast US by the first week of March. So stay tuned for more details on this weekend’s storm and pattern changes moving forward, this week.

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