Forecast Updated Tue 11:00 AM — For many areas, the snow never made it to the ground, although the model forecast was pretty good Here’s the current situation at 11 AM—

from last night…

With current average high temperatures for this week running in the low to mid 50’s, today’s cold temperatures made it difficult to remember that [astronomical] Spring starts in another week.

This week, we’ll have a few more reminders that we’re still in winter.

Tomorrow, Tuesday, may have a brief period of light snow showers/flurries in the morning, especially northwest of the city. Indeed, the model blend shows a greater than 50% chance of light snow showers far northwest of the city before a change to light rain.

This afternoon’s RAP model shows very light snow showers moving through late morning.  No accumulation expected.  (The air has been so dry, it’s unclear how much of this may evaporate before reaching the ground.)  

Tonight’s 00z HRRR model, just available, has a similar forecast.

The total amount of precipitation on Tuesday will be very light, possibly not enough to reduce the wildfire danger.

A more significant rain maker is expected on Thursday, as the low pressure system that caused the blizzard in Colorado moves eastward with possible secondary low pressure development near the coast.

The GFS model suggests enough secondary development and cold air to allow a changeover to light snow showers early Friday morning. Right now, no accumulation expected.

Outlook Updated Tue 5:58 PM — Current models do have the cold front pushing precipitation out of our area for Saturday.  (There had been the possibility that the front would hang up right over us, keeping things cloudy and wet.)  Sunday also looks good right now.   Cooler, more seasonable temperatures for both Saturday and Sunday.

from Sunday….

As mentioned in my previous post, a transition in our area from a jet stream trough to a jet stream ridge (warmer weather) will occur during this week.

This ridge will allow temperatures to reach into at least the 60s (and possibly near 70º) for the Philadelphia area by Wednesday. 

The current Model Blend forecast high temps (Blue Bell -Wings Field, add about 1 to 2º for Philadelphia.)

Wednesday — 62º
Thursday — 66º
Friday — 66º 

 The uncertainty with these temps is high.   The  Model Blend standard deviation is 3º-5º.  In these situations, the NBM can be on the low side.

For Next Weekend:  Also uncertain is the eventual development and track of a deep low pressure system in center of the country from confluence of the southern and northern jet streams.   We may enter a prolonged period of rain that goes into the weekend, OR we may have a cold front push far enough south to suppress the moisture to our south and give us a dry, cooler, and windy weekend.