Doug Simonian

Inching Closer to Snow this Weekend

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As many of you know by now, there are two threats for snow over the next few days: the first of which starting late Thursday night and Friday, and the second of which on Saturday. While most model guidance verbatim is still not impressive with either threat, there have been many impressive trends today, particularly with the second storm, as that one has a much higher ceiling. The UKMET model, for example, shows a big snowstorm for a 2nd straight run, the ECMWF and its ensembles made another large jog westward.

The first disturbance is via a Polar shortwave that dives southward into the Northern Plains from Canada. This shortwave is pretty potent and resembles a lot of past setups that have a late-blooming low pressure that drop a few inches of fluffy, high-ratio snow. What’s preventing this event from having a truly high ceiling is that this shortwave is not truly detached from the downstream flow and initial vortex in SE Canada, so it cannot become its own entity. This shunts the positive vorticity advection main access offshore where there is a separate area of disjointed vorticity rather than the area where the main shortwave is. The main shortwave instead simply serves to buckle the flow a bit and provide more dynamics rather than directly correlate with the track of the system. That being said, this shortwave may still trend amplified enough to allow a last second north jump with a weak low pressure offshore that can give a few inches of snow to coastal areas.

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John Homenuk

AM All Zones Update: Rain likely this afternoon

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Periods of steady rain will return to the forecast this morning and likely will be steady and heavy at times this afternoon. A strong storm system developing through the Northeast US will draw increasingly notably moisture northward today, and as a warm front moves through precipitation will become more prevalent throughout the area.

Beginning as showery, drizzly precipitation this morning, rainfall totals of around 0.10″ are likely through early afternoon. But a period of steadier rainfall associated with enhanced lift in the atmosphere could bring totals over 0.60″ for some areas by sunset tonight. A few isolated rumbles of thunder can’t be ruled out either.

NAM model showing periods of heavy rain in the Northeast this afternoon.

NAM model showing periods of heavy rain in the Northeast this afternoon.

The system shifts north of the area later tonight, after 8pm, with drying conditions expected as the evening goes on. Colder air will then begin surging into the area from the west. This arctic air will continue pushing into the region through Wednesday, with temperatures falling much below normal.

Stay tuned for more this morning on the development of wintry weather this weekend.

John Homenuk

PM All Zone Update: Rain continues, heavy at times Tuesday

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An approaching storm system will bring continued drizzle and showers through tonight — with periods of steady rainfall expected on Tuesday. The disturbance affecting our area tonight is quite weak, but moisture in the atmosphere’s low levels is creating drizzle and showers. These will continue on and off for the next few hours — but accumulation is expected to be light.

Temperatures will continue warming through the morning hours as southerly winds continue. This southerly flow will be drawing more moisture into the area ahead of the stronger storm system approaching on Tuesday. An area of steady to heavy rain is expected to move through the Mid Atlantic and Northeast from the late morning to early afternoon hours, producing rainfall totals between 0.35″ and 0.50″ during its passage.

 

Simulated radar imagery valid 1:00pm on Tuesday.

Simulated radar imagery valid 1:00pm on Tuesday.

These periods of steady rain are likely to continue during the afternoon, with the heaviest rain spreading north into the northern zones of Southeast NY and Connecticut during the mid afternoon hours. As a low pressure area shifts north of the area during the day, clearing will occur from southwest to northeast through the area.

Improving weather conditions are expected after sunset, as west-northwesterly winds begin ushering in a drier and colder airmass. Breezy conditions may develop by late afternoon as the frontal boundary moves past the area. Cold air will surge into the area by Wednesday with arctic air pushing south from Canada.

 

Miguel Pierre

Test Blog for All Zones: Rain Tonight and Tomorrow Colder Late Week

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Overview: A weak disturbance will bring some light precipitation to parts of the region during today. A larger storm system will impact the region with more rainfall and milder temperatures tonight and Tuesday. A cold front moving through by Wednesday will deliver much colder air later next week. We also watching storm system that could some snowfall to region on Friday. Especially over Southern NJ and Long Island.

Tonight: Mostly cloudy. 40% chance of rain showers. Lows in the upper 30s then temperatures rising late.

Tuesday, Mostly cloudy and much milder. Periods of rain likely. Highs in middle 50s.

Wednesday: Partly sunny and still very mild with highs in the middle 50s.

Thursday: Mostly sunny and colder. Highs in the middle 30s.

Friday: Mostly cloudy and very cold. Highs in the lower 30s.

Saturday: Mostly cloudy and very cold. A 30% chance of light snow. Highs in the upper 20s.

Sunday: Mostly cloudy with a 30% chance of light snow. Highs in the lower 30s.

Monday: Mostly sunny and cold with highs in the lower 30s.

Today's NAM valid for 10:00am tonight shows a low pressure passing to our northwest, which may trigger scattered light precipitation. There is also plenty of southwesterly flow as evidenced on the bottom left -- particularly for the coast.

Today’s NAM valid for 10:00am tonight shows a low pressure passing to our northwest, which may trigger scattered light precipitation. There is also plenty of southwesterly flow as evidenced on the bottom left — particularly for the coast.