Perhaps no one noticed, but the models did very poorly with today’s (Friday ‘s) forecast.  There was supposed to have been heavy rain followed by sun in the afternoon. Neither occurred. Let’s see if the weekend forecast is more accurate.

A frontal boundary draped near the Great Lakes won’t move until Monday.  (At least that’s what the models show.) High pressure builds in Saturday.  Mostly sunny skies with high temperatures near 55.

Late Saturday,  high pressure retreats to the northeast and an easterly flow of moisture develops causing low cloudiness.  Mostly cloudy skies expected for Sunday with high temp again near 55.

Saturday Update:  I want to mention that the long range models have been consistently showing an outbreak of deep cold air for next weekend, the beginning of April.  Winter has at least one more guest appearance.

As I’ve mentioned,  over the past two weeks, the GFS model has been showing the return of cold air and the possibility of snow for this coming weekend.

The models continue to show this possibility.  The GFS model QPF for late Saturday night into Sunday is well over 0.40 inches water equivalent, but the exact track and timing of the coastal low’s intensification is still uncertain and continues to be difficult to pin down.  What does seem likely is that the upper air thermal profile supports snow, vs rain.

Even if the expected QPF value gets consistent, predicting snowfall amounts this time of year is very difficult.  So much will depend upon the timing (daytime vs nighttime) ground temperatures (which are high for this time of year),  near surface air temperatures and rate of precipitation (which affects dynamic cooling.)

So this is NOT a snowfall where you multiply the QPF by 10 and you get the snowfall totals.  Instead, all of those factors above turn into a general crapshoot predicting accumulation.   To simplify, snowfall during the daytime hours reduces accumulation significantly, especially on dark paved surfaces.   Grassy surface accumulation almost always exceeds accumulations on sidewalks, unless precipitation rates and QPF amounts are very high.  Right now, it doesn’t look like a ‘big event’.

Both the NAM and GFS models have light snow starting Saturday evening and continuing into at least Sunday morning, maybe more prolonged. Temperatures will be cold and below average late Saturday through Tuesday.

Thurs 11PM – NAM QPF looking impressive at 0.56 inches water equivalent.  Accumulating snow looking more likely during the day Sunday.

High pressure over our area will bring sunny skies and cooler temperatures (although still above average) on Saturday.  High temperature about 55.

The high will retreat to the northeast late Saturday, allowing an easterly flow to develop.  Some cloudiness develops late Saturday afternoon.

The easterly flow will combine with moisture from the south, giving us a cloudy Sunday with a good chance of rain for much of the day.  Forecast High 54.  (It wouldn’t surprise me if tempertures struggle to hit 50.)