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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – March 11 , 2018

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

Forecast Discussion:

The front came through about three hours later than I called for on Friday. We had clouds, winds, and virga (rainfall that evaporates before hitting the ground). Figure 1 shows the position of the front as of Saturday late night (about the time I was setting clocks forward).

Figure 2 is the upper air map for Saturday PM - the red line to our east (pink dot for Longmont) is the upper air feature that brought the front in.  The ridge to the west (big blue line) is growing!

Figure 1: Current Surface map from Saturday PM from the weather channel.

Figure 2: The current 500mb upper air map from Saturday PM from the RAP model.

The longer range forecast:

This week will be quite warm and dry. Monday will see mid 50'sF.  Tuesday upper 60'sF.  Wednesday 70'sF. This is the work of the big ridge.  Figure 3 is the upper air map for Tuesday night, the ridge is almost overhead.

The deep trough over the eastern Pacific ocean in Figure 3 will replace that ridge by the weekend (see Figure 4 - Saturday night). Some models are now bringing in 2/3's of an inch of rain Saturday PM through Monday next week.  Figure 5 is a zoom-in on the weather for next weekend.  This model has about 1/2 of an inch of rain.  Note temperatures remain too warm for much in the way of snow.  That's how it looks for now.  Tune in again tomorrow!

Figure 3: The 500mb upper air map for Tuesday PM from the GFS. Troughs in red, ridges in blue.

Figure 4: The 500mb upper air map for Saturday PM from the GFS. Troughs in red, ridges in blue.

Figure 5: the last 3 days of the 10 day graphical forecast from weatherunderground.com

Current Weather

Sunny

Sunny

55°F

UV Index
9 Very High
Pressure
29.76 Rising
Visibility
8 miles
Dewpoint
18 °F
Humidity
23%
Wind
W 6 mph
Gust
13.3 mph
Wind Chill
55 °F

Hourly Forecast

Today
12 PM
58°F
Partly sunny
Today
1 PM
59°F
Intermittent clouds
Today
2 PM
59°F
Intermittent clouds
Today
3 PM
60°F
Intermittent clouds
Today
4 PM
60°F
Intermittent clouds
Today
5 PM
58°F
Intermittent clouds
Today
6 PM
57°F
Intermittent clouds
Today
7 PM
56°F
Intermittent clouds
Today
8 PM
53°F
Intermittent clouds
Today
9 PM
50°F
Intermittent clouds
Today
10 PM
48°F
Intermittent clouds
Today
11 PM
45°F
Intermittent clouds

7 Day Forecast

Intermittent clouds

Wednesday

60 °F

Turning cloudy and cool


Mostly cloudy

Wednesday Night

40 °F

Partly to mostly cloudy


Partly sunny w/ showers

Thursday

53 °F

Times of clouds and sun with a couple of showers; cooler


Partly cloudy

Thursday Night

41 °F

Partly cloudy


Mostly cloudy

Friday

57 °F

Mostly cloudy


Partly cloudy

Friday Night

39 °F

Partly cloudy


Mostly sunny

Saturday

66 °F

Mostly sunny and warmer


Mostly cloudy w/ t-storms

Saturday Night

43 °F

Mostly cloudy with showers and thunderstorms late


Mostly cloudy

Sunday

64 °F

Mostly cloudy with a thunderstorm in spots in the afternoon


Intermittent clouds

Sunday Night

44 °F

A thunderstorm in the evening; otherwise, becoming clear


Sunrise and Sunset

Sunrise
5:51 AM
Sunset
8:03 PM

Based on AccuWeather data