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10pm Update 3/23: Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – March 23-24, 2019

This content was originally published by the Longmont Observer and is licensed under a Creative Commons license.

10 PM Update Saturday 3/23:

The previously described short wave will be rolling over the state today (Sunday) kicking off a chance of rain and thunderstorms, some containing small hail, mainly after 5pm Sunday and ending by 11pm. A little taste of Spring weather now that Spring has started - and before the 70'sF hit later this week. I'll have my camera with me for any thunderheads that form... (Note, presently, severe weather is not expected in Colorado.)

figure 1 update: The day 2 forecast made Saturday for Sunday of severe weather and convection regions from the NWS Storm Prediction Center in Norman, OK.

End 10pm Update 3/23

Forecast Discussion:

I'm barreling down the interstate typing on a wifi hotspot from the back seat. But we're getting an update done!

We drove through a blinding (but geographically small) snow storm near Flagstaff Thursday PM. That storm system hit Colorado on Friday and even produced a significant land spout near Eads. What excitement!

Figure 1 shows (by Sunday morning) that we are between systems, but another low is dropping moisture to the west of our state. Try as I could, my graphics program would not save the (even flattened) trough and ridge lines in Figure 2, but the big picture is the large ridge in the west with an active southern branch of the jet stream bringing many small ripples of energy over the state. That means mountain snows and rain showers on the plains. And a warming trend.

Over the next 48 hours, we'll see a dusting or coating of snow near Longmont with night time precipitation. We might pick up up to 1/4th of an inch of water during that time (Figures 3 and 4).

The longer range forecast:

That ridge takes hold and we rocket to the 70'sF by mid-week. Oh that will feel good - even Phoenix wasn't that warm this week. Out further in the week, we have indication of a big trough returning and more rain and snow with cooler temperatures, but we'll look at that when I return to normal forecasting duties in a couple of days.

Figure 1: The forecast surface map for Sunday AM from NCEP.
Figure 2: The 500mb forecast upper air analysis for Sunday PM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges. (Missing this time, no matter what i did.)
Figure 3 : the forecast accumulated snow map from the GFS and weather5280.com for Colorado, through Sunday PM.
Figure 4 : the forecast accumulated precipitaiton map from the GFS and weather5280.com for Colorado, through Sunday PM.
Figure 5: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com

Current Weather

Mostly cloudy

Mostly cloudy

64°F

UV Index
6 High
Pressure
29.75 Falling
Visibility
8 miles
Dewpoint
35 °F
Humidity
33%
Wind
NNE 3.8 mph
Gust
8.3 mph
Wind Chill
64 °F

Hourly Forecast

Today
2 PM
68°F
Thunderstorms
Today
3 PM
66°F
Mostly cloudy
Today
4 PM
63°F
Intermittent clouds
Today
5 PM
60°F
Intermittent clouds
Today
6 PM
57°F
Mostly cloudy w/ t-storms
Today
7 PM
55°F
Intermittent clouds
Today
8 PM
53°F
Thunderstorms
Today
9 PM
51°F
Cloudy
Today
10 PM
49°F
Cloudy
Today
11 PM
47°F
Cloudy
Tomorrow
12 AM
46°F
Cloudy
Tomorrow
1 AM
45°F
Cloudy

7 Day Forecast

Partly sunny w/ t-storms

Wednesday

68 °F

A shower in spots this morning, becoming breezy this afternoon with a thunderstorm


Thunderstorms

Wednesday Night

37 °F

A thunderstorm this evening; otherwise, mostly cloudy


Intermittent clouds

Thursday

62 °F

A blend of sun and clouds


Mostly cloudy

Thursday Night

38 °F

Mostly cloudy


Partly sunny

Friday

64 °F

Some sun; breezy in the afternoon


Partly cloudy

Friday Night

36 °F

Partly cloudy


Partly sunny

Saturday

66 °F

Partial sunshine


Mostly clear

Saturday Night

41 °F

Clear to partly cloudy


Mostly cloudy

Sunday

78 °F

Rather cloudy and warmer; breezy in the afternoon


Mostly cloudy

Sunday Night

43 °F

Rather cloudy


Sunrise and Sunset

Sunrise
5:59 AM
Sunset
7:56 PM

Based on AccuWeather data