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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – October 16th, 2018

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

Forecast Discussion:

Our storm (with some ex-Sergio moisture incorporated in it) is off to the east and very dry/sinking air is in place over Colorado (red colors in Figure 1).  The surface map for today (Figure 2) has a low to our southwest that is kicking off storms in Arizona and southern New Mexico.  That instability and moisture is forecasted to stay far south of us.

Figure 3 is the upper air map and the trough that has lower heights over the state, which makes our weather cooler than normal. That cut-off low over Arizona is the feature generating those storms. Interesting set up!

Figure 1: The visible satellite image from Monday PM from NOAA

Figure 2: The forecast surface map for Tuesday PM. From NCEP.

Figure 3: The 500mb forecast upper air analysis for Tuesday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

The longer range forecast:

We stay cool and dry for a long time.  Figure 4 shows the ridge to our west and lower heights still over Colorado Friday AM.  Figure 5 shows the ridge next Monday still dominate over the West.

El Nino update

Figure 6 is a quick look at the El Nino status.  It is clear that El Nino is coming on (and is here now). The forecast off into next year keeps us in El Nino conditions for a long time to come (Figure 7).  The winter forecasts I'm seeing have Colorado cooler than normal (by a bit) and wetter than normal (somewhat).  More later as things shape up!

Figure 4: The 500mb forecast upper air analysis for Friday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Figure 5: The 500mb forecast upper air analysis for Monday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Figure 6: Sea Surface Temperature anomalies (departures from normal) for the equatorial Pacific from NOAA and the IRI.

Figure 7: The forecast El Nino Southern Oscillation (ENSO) index from multiple models by three month averages (for example, NDJ = November, December, January). From the IRI and CPC.

Current Weather

Mostly cloudy

Mostly cloudy

63°F

UV Index
1 Low
Pressure
29.75 Falling
Visibility
8 miles
Dewpoint
24 °F
Humidity
22%
Wind
W 5.9 mph
Gust
13.7 mph
Wind Chill
63 °F

Hourly Forecast

Today
6 PM
61°F
Partly sunny
Today
7 PM
58°F
Partly sunny
Today
8 PM
55°F
Intermittent clouds
Today
9 PM
51°F
Intermittent clouds
Today
10 PM
48°F
Intermittent clouds
Today
11 PM
45°F
Intermittent clouds
Tomorrow
12 AM
43°F
Intermittent clouds
Tomorrow
1 AM
41°F
Intermittent clouds
Tomorrow
2 AM
39°F
Intermittent clouds
Tomorrow
3 AM
38°F
Intermittent clouds
Tomorrow
4 AM
37°F
Intermittent clouds
Tomorrow
5 AM
36°F
Intermittent clouds

7 Day Forecast

Partly sunny

Thursday

65 °F

Partly sunny


Intermittent clouds

Thursday Night

34 °F

Partly cloudy


Partly sunny w/ showers

Friday

53 °F

Cooler with times of clouds and sun; a couple of showers late in the afternoon


Showers

Friday Night

33 °F

A couple of showers in the evening; otherwise, cloudy


Mostly cloudy

Saturday

60 °F

Mostly cloudy


Intermittent clouds

Saturday Night

36 °F

Partly cloudy


Intermittent clouds

Sunday

62 °F

Times of sun and clouds


Mostly cloudy

Sunday Night

33 °F

Becoming cloudy


Showers

Monday

52 °F

Cloudy and cooler with occasional rain; windy in the afternoon


Intermittent clouds

Monday Night

29 °F

Windy in the evening; partly cloudy


Sunrise and Sunset

Sunrise
6:50 AM
Sunset
7:22 PM

Based on AccuWeather data