Good evening all and happy Friday! For you skiers, this storm could not be more perfectly timed. A long holiday weekend and a foot of fresh powder on its way. For you teachers….I’m sorry.

Mid-Level Water Vapor Loop Friday Evening – College of DuPage

Above is a water vapor loop for this evening. A water vapor look is just as it sounds. A 22,000 mile high view of the moisture in the atmosphere. Yellows indicate drier air while whites and greens indicate moisture rich air. The mass of white and green swirling in the middle of the screen is our storm system for Saturday night and Sunday.

Note: the northward flow of moisture from the Gulf of Mexico. The storm is tapping into moisture rich air.

The below image from the Weather Prediction Center shows the storms progression from west to east across the country.

Low Pressure Track – WPC

Saturday

Throughout the day Saturday the storm center will travel northeast from the southern Plains states to the Mid-Atlantic. As it continues to gather Gulf of Mexico moisture, the storms precipitation field will expand tremendously.

Saturday Storm Progression – Tropical Tidbits

The above forecast loop starts 1 am Saturday morning and ends 1 am Sunday morning. Snow overspreads the region from west to east after dinnertime Saturday night. For an estimate of when the first flakes will begin to fly, here is a forecast from the National Weather Service in Norton, MA.

Snowfall Start Time – NWS

Saturday Night & Sunday

Overnight Saturday and into Sunday morning is when the bulk of the precipitation falls. Snowfall rates on the order of 1-3″/hr are possible. Travel is likely very difficult as snow removal crews struggle to keep up.

Saturday Night & Sunday Storm Progression – Tropical Tidbits

The above forecast map starts 7 pm Saturday and ends 1 am Monday morning. All locations starts as snow. Slowly but surely warmer air aloft works it way in flipping locals south of the Massachusetts turnpike and inside of Route 495 to sleet and freezing rain. Places out along Route 2 in northern Mass may even flip to sleet for a time. Locations south and east of Interstate 95 like flip to rain for a period. Far southeastern MA, Rhode Island, Cape & Islands flip to rain for an extended period.

Precipitation Type Forecast

Precipitation Type Forecast

Blue: All Snow

Red: Mainly Snow -> Sleet -> Ice -> Snow

Orange: Snow -> Sleet -> Ice -> Rain -> Snow

Green: Snow -> Sleet -> Rain -> Snow

Snowfall

Expected Snowfall

Ice Accumulation

Another aspect to this system is the potential for significant icing to accumulate during the transition period early Sunday morning. Temperatures below freezing are likely to be locked in at the surface while temperatures aloft warm above freezing. This allows for precipitation to fall as sleet and freezing rain. For potential ice accretion amounts, I will turn to the experts at the National Weather Service.

Ice Accumulation Forecast – NWS

Sunday Night – Total Lunar Eclipse

If the clouds clear out Sunday night, then we will be able to witness the only total lunar eclipse of 2019. Named the “Super Blood Wolf Moon”, starting around 10:30 pm, if visible, the moon should begin to darken. Between 11:40 pm and 12:40 am, the moon will be totally eclipsed by the Earth’s shadow. For a look at how a lunar eclipse occurs:

Lunar Eclipse Mechanics

Monday

Monday morning will likely feature the coldest air of the season with low temperatures in the single digits to near or below zero. Fortunately the kids don’t have to go to the bus stop, but for those still digging out from the storm, it will be dangerously cold. Stay warm!

Monday AM Low Temperatures – WeatherBELL

Long Range

Another storm is possible towards the end of next week. Right now, that system looks warmer than this one, but there is plenty of time to sort the out details.

EPS Ensemble Mean – PivotalWeather

-Chris


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