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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – May 25, 2018

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

Forecast Discussion:

We're still in a very quiet, very warm pattern.  It is 87F in Longmont as I type (with beautiful blue skies.)

Figure 1 is the upper air pattern with a southern branch ridge (blue line) under a northern branch ridge (up in to central Canada, covering the central U.S. , but not marked). The atmosphere is sinking gently, compressing, and warming.  Warm air aloft is flowing in from the southwest making it harder for storms to form.  Figure 2 is the surface map for today - there is just a nice big high pressure system, at the surface, over Colorado.

Tomorrow, a hint of change is showing up out in California and Nevada, but we are still under a big high pressure center and headed above 90F.

Figure 1: The 500mb upper air analysis forecast from the GFS for Friday midday.

Figure 2: The forecast surface analysis map for Friday midday from NCEP.

Figure 3: The forecast surface analysis map for Saturday midday from NCEP.

The longer range forecast:

Figure 4 shows another cut-off low rolling in from the west by the end of the weekend.  This might pull moisture in again and slide cold air, aloft, into place to give us rain and thunderstorms.  We 'might' have a stormy Memorial Day.

As is the pattern, when the weather gets quiet, we take a look into the distant future.  El Nino models were compared, and that comparison was released a few days ago (May 18th). The oceans are near neutral conditions for the summer with a good chance of El Nino conditions later this year (Figure 5). The seasonal outlook for the summer is out from NOAA (Figure 6).  Western Colorado is in the above normal chances for precipitation, eastern Colorado is in equal chances of normal precipitation.  Southwest Colorado is strongly expected to be warmer than average for the summer while northeast Colorado is expected to be warmer than average.

Figure 4: The 500mb upper air analysis forecast from the GFS for Monday midday.

Figure 5: The IRI/CPC Pacific Nino 3.4 Model Outlook. Multiple models are compared.

Figure 6: The June - August seasonal outlook from NOAA.

Current Weather

Sunny

Sunny

42°F

UV Index
3 Moderate
Pressure
29.96 Steady
Visibility
8 miles
Dewpoint
28 °F
Humidity
58%
Wind
NW 1.6 mph
Gust
3.7 mph
Wind Chill
42 °F

Hourly Forecast

Today
10 AM
47°F
Partly sunny
Today
11 AM
53°F
Partly sunny
Today
12 PM
57°F
Partly sunny
Today
1 PM
60°F
Partly sunny
Today
2 PM
62°F
Partly sunny
Today
3 PM
63°F
Partly sunny
Today
4 PM
64°F
Partly sunny
Today
5 PM
63°F
Partly sunny
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

7 Day Forecast

Partly sunny

Thursday

64 °F

Partly sunny


Intermittent clouds

Thursday Night

34 °F

Partly cloudy


Partly sunny w/ showers

Friday

54 °F

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


Showers

Friday Night

32 °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

36 °F

Becoming cloudy with a shower in spots late


Showers

Monday

50 °F

Mostly cloudy and cooler with occasional rain; windy in the afternoon


Intermittent clouds

Monday Night

31 °F

Windy in the evening; partly cloudy


Sunrise and Sunset

Sunrise
6:50 AM
Sunset
7:22 PM

Based on AccuWeather data