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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – August 12th, 2018

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

Forecast Discussion:

Amazingly, we move another notch drier today. There is only 1/2 inch of precipitatable water in the atmosphere as of Saturday morning (we get excited about rainfall as it approaches an inch or more). We have orange and red colors painted overhead on the water vapor satellite image (Figure 1). The thicker smoke is a few counties closer to us than it was yesterday as that next trough begins to dig into the Pacific Northwest (it is a very sharp clean cut into the smoke in Washington State and Oregon on Figure 2!).

The precipitation for the next 3 days is extremely close to zero on the GFS outlook (Figure 3).  A touch of monsoon moisture may wet the Western Slopes over the next few days.  That would be nice.

Figure 1: the water vapor satellite image from Saturday AM. Reds/Oranges are dry air, greys/whites are moist air regions.

Figure 2: The HRRR (high resolution rapid refresh) model forecast of smoke at all levels for Sunday midday.

Figure 3: The total accumulated precipitation for the next 3 days between Saturday AM and Tuesday AM from the GFS and weather5280.com

The longer range forecast:

Our rain forecast is pegged at zero until Tuesday afternoon. A bit of moisture returns then, with a deeper surge showing up on Friday (Figure 4). We might be seeing our last 90'sF this weekend and Monday.

Since the weather is very quiet, let's look at some really long range trends.  Based on the longer range models and sea surface temperature trends, NOAA has painted us (Figure 5) as having better than average chances of being warmer than normal for the end of the Summer into the Fall (September, October, November or "SON" in the legend).  Similarly, the precipitation outlook for this time (Figure 6) has us at near normal precipitation with above average amounts in the desert southwest of the U.S.

Figure 4: the next 10 days of the graphical forecast for Longmont, CO from weatherunderground.com

Figure 5: the 3 month temperature anomaly outlook for N. America (Longmont is the pink dot) issued July 19th.

Figure 6: the 3 month precipitation anomaly outlook for N. America (Longmont is the pink dot) issued July 19th.

Current Weather

Partly sunny

Partly sunny

65°F

UV Index
4 Moderate
Pressure
29.81 Falling
Visibility
8 miles
Dewpoint
20 °F
Humidity
18%
Wind
SE 4 mph
Gust
10.8 mph
Wind Chill
65 °F

Hourly Forecast

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
Today
10 PM
48°F
Intermittent clouds
Today
11 PM
45°F
Intermittent clouds
Tomorrow
12 AM
44°F
Intermittent clouds
Tomorrow
1 AM
42°F
Intermittent clouds
Tomorrow
2 AM
40°F
Intermittent clouds

7 Day Forecast

Partly sunny

Thursday

64 °F

More sun than clouds


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


Showers

Monday

48 °F

Cloudy and chilly 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