#weather #paweather #wx #pawx #philadelphia

Friday Forecast Update & Saturday Outlook—

Update Thu 03/09 @ 5:52 PM — The next weather maker moves in early Friday afternoon. Rain moves in from the west, between 1 and 3 PM Friday. It will become increasingly windy Friday night. About 0.5-0.75″ of rain expected before it ends around daybreak Saturday.

It appears that the primary low will spawn a complex secondary structure early Saturday; low pressure will develop far off the coast to our south and another center near NYC.

The rain and most of the energy will move away on Saturday, but residual moisture Saturday morning will likely result in some snow flurries. Saturday looks to become partly to mostly cloudy in the afternoon with some gradual clearing later in the day.

The system coming in late Sunday is still a rain event for Monday, but may begin as light snow in northern and western suburbs.

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Monday’s Storm Trending Warmer

Update Thu 03/09 @ 9:57 AM — Last night’s models have the lower levels of the atmosphere (< 2000 feet) trending warmer, reducing the likelihood of snow, even at the start. What was already a marginal chance for non-accumulating winter precip, at least at the start, has reduced to a very low chance.

This storm is still several days away and additional changes in the forecast are likely to occur.

Nonetheless, we have entered a very active weather pattern with disturbances from the Pacific, affecting California, are rapidly crossing the country and spawning additional low pressure development on this coast. Slight changes in the flow can create big changes in our weather. Stay tuned.

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Rain Friday afternoon. Possible Snow-Rain Mix Monday morning

Update Wed 03/08 @ 8:02 PM — Rain is still expected Friday to move in from the west between 1 PM and 3 PM and continue into early Saturday morning. Very slow clearing on Saturday, possibly with lingering sprinkles.

Of interest is a new storm now expected to form Sunday night to our south and intensify as it reaches the coast. The GFS and ECMWF both show a mix of snow and rain possible before daybreak Monday, likely changing to all rain during the day.

Temperatures are expected to be above freezing, so little or no accumulation is currently expected. This is a changing situation.

Here’s the latest ECMWF and GFS for Monday morning—

Here’s the GFS—

Something to watch. I’ll keep my eye on any changes.

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Previously Posted Tue 5:51 PM —

The weather will continue to be fair and relatively cold through Friday.

An approaching storm on Friday is now being forecast to exit faster than previously predicted.

It appears that rain will begin Friday afternoon with this storm—

The models have backed away from this being a storm with secondary coastal development. It will not be as deep a storm as previously forecast. The ECMWF model is leading this trend.

Rain likely ends Saturday morning with partial clearing occurring during the day. It will be windy and colder.

Much of next week looks to be colder than average. No snow seen in the forecast.

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#weather #paweather #wx #pawx #philadelphia

Snow Accumulation Tonight? Fuhgeddaboudit!

Update Mon 3/06 5:56 PM —This afternoon’s models have taken the trace snowfall predicted by last night’s models and have moved accumulations even closer to zero. The trend today has been for accumulating snowfall to be even further northward.

Here’s the very latest GFS snowfall accumulation for tonight—

While some snow is expected to fall in our area, minimal accumulating snow expected due to temperatures being above freezing and “surface skin” temperatures also above freezing during the time of the precipitation.

While temperatures may fall close to 32º just outside the city by 7AM, it will occur after the precipitation has exited the area.

NBM showing exiting precip as 32º line drops south at 5AM Tuesday—

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Monday Forecast Update

Update Mon 3/06 9:05 AM —It appears that the fast moving weak storm for tonight will bring down enough cold air to allow the precipitation to fall as snow. The timing of the storm, occurring at night, helps with this colder thermal profile.

While the light precipitation in the immediate PHL area will fall as snow, surface temperatures will be above freezing in areas south of Doylestown. No accumulation on roadways and little accumulation on grassy surfaces expected in these areas.

Snow starts 11PM to midnight and ends before daybreak Tuesday.

North of Doylestown, accumulating snow is forecast by the models. There’s quite a range of accumulations forecast—

NBM:

NAM-NEST:

Previously Posted Sun 5:55 PM —

I don’t see much significant weather this coming week until next weekend, although a pattern change to colder weather is hinted at for us for the following week, according to the GEFS.

With the exception of a warmer Monday (53-54º), for the rest of the week, highs will be in the upper 40’s (Blue Bell), close to the seasonal average high of 49º (Blue Bell) and 50º (Philadelphia).

This Week’s Weather Highlights

Monday night—

A weak storm moves through Monday night with some rain. It continues to be windy, especially Tuesday through Wednesday. (Well, it IS early March).

Friday Night into the Weekend—

Another storm approaches for next Saturday and a strong secondary low, a coastal storm, develops.

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