The secondary low that has been closely monitored in recent days is now producing snowfall over the Rockies and now it’s looking like the focus of heaviest snowfall will be north of Denver due to the low tracking a little too close to Denver. This was highlighted back in yesterday’s post. In saying that, Denver may still see 2-4, locally 6 inches when all is said and done but it’s nothing compared to what the Laramie Range will experience where both Cheyenne and Casper may get ultimately shut down by 1-2 feet of snow.

This is going to be a long drawn out process with the trough deepening in a gradual fashion as the low doesn’t cross southern Colorado out into the central Plains particularly fast, therefore explaining why snow totals will be high across northeast Colorado, southeast Wyoming.

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The lead storm which broke multiple snow records across the Bismarck, ND area, is responsible for tapping the cold air over Canada and pulling it south over the N. Plains and Rockies and so as snows crank tonight and through tomorrow, all the way into Wednesday, with inches quickly mounting, expect falling temperatures throughout. Lows will fall through the teens tonight in both Casper and Cheyenne and expect highs no warmer than the mid-20s tomorrow. Low 20s Wednesday and perhaps the 10s on Thursday once the low finally clears out. Lows Wed night into Thursday may well fall winto single digits with such cold places as Laramie dipping below zero.

Denver will be in the mid-30s tomorrow, near 32 Wednesday, possibly upper 20s on Thursday, all before a gradual warming takes places towards late week into the weekend.

Here’s the latest GFS snow totals through the next 60 hours.

Check out this snow totals graphic off weather.com.

The trough and cold pool will deepen into the Southwest through 72 hours, pumping a late spring-like ridge into the East. This should present highs well into the 80s from the Lower and Mid-Mississippi Valley into the interior Mid-Atlantic all the way to Philadelphia, a warm front seperates Philly from DC and so highs reach the mid-80s in DC, Balt and even Philly by Thursday while it may not get out of the 60s in NYC. However, the position of that front is much much up in the air and so NYC could be anything from 60s to 80s, depending on position and a lot can change between now and then.

Here’s the latest GFS ensemble means.

Note the trough bowling balls it’s way across the country over the next 5 days.

48 hrs

72 hrs

96 hrs

This setup, puts down a lot of water over the Mississippi and Ohio Valley over the next 72 hours.

We need to watch out for the severe potential with this western trough/eastern ridge over the next several days.

NAO, AO, PNA All Point To Cooler Than Normal East, Warmer Than Normal West In May

By the end of the week, much cooler air has returned to the East while the west warms.

As we head towards late April, the NAO will return to negative along with the AO and with the PNA set to go positive, this sets the stage for a western ridge and eastern trough.

Here’s a look at the latest indexes.

NAO

AO

PNA

These all point to a cooler/wetter than normal month of May in the East, warmer and drier than normal in the West!

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