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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – October 22, 2017

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

Forecast Discussion:

The cold front came through pre-dawn with blustery winds that faded out as Saturday went on.  We did warm up to 60F, which is about 5 degrees below normal.  Today (Sunday) we return to 71F which is 6 degrees above normal.  The front is way down into New Mexico and is off making severe weather in Oklahoma and North Texas (Figure 1). Behind the front, our temporary cold can be seen as the turquoise colors over our region.   The upper air pattern for Saturday PM (Figure 2) shows the trough (red line) past us already.

Figure 1: Saturday PM Infrared Satellite Image with surface analysis

Figure 2: Saturday PM 500mb upper air map with red lines in troughs, blue lines on ridges

In the longer range:

The western ridge, already present Saturday night in Figure 2, builds across the west and warms us up, but gives us northwest flow aloft. By Wednesday morning, we are well under the tilted ridge, but change is also on the map (Figure 3).   The shortwave trough over western Canada will come down and help back build our eastern US trough towards us (Figure 4) by Friday AM.  The surface map on Friday AM shows a small blob of moisture over the Front Range (Figure 5).  With the troughs and ridges on Figure 4 drawn on Figure 5, note that most of the precipitation is orientated with the troughs and on the right side of those troughs.  A neat bit of meteorology illustrated there!

A cool down, and somewhat better chance of moisture, is in the forecast for Thursday afternoon on into the weekend...

Figure 3: GFS forecasted 500mb upper air map Wednesday AM. Longmont is the pink dot as always.

Figure 4: GFS forecasted 500mb upper air map for Friday AM. Troughs and ridges are marked again.

Figure 5: GFS forecasted surface precipitation map for Friday AM. Troughs and ridges are marked again matching their positions in figure 4.

Current Weather

Mostly cloudy

Mostly cloudy

53°F

UV Index
0 Low
Pressure
29.82 Rising
Visibility
8 miles
Dewpoint
39 °F
Humidity
58%
Wind
SSW 2.7 mph
Gust
5.9 mph
Wind Chill
53 °F

Hourly Forecast

Today
10 PM
50°F
Thunderstorms
Today
11 PM
48°F
Cloudy
Tomorrow
12 AM
46°F
Cloudy
Tomorrow
1 AM
44°F
Cloudy
Tomorrow
2 AM
42°F
Mostly cloudy
Tomorrow
3 AM
40°F
Mostly cloudy
Tomorrow
4 AM
38°F
Mostly cloudy
Tomorrow
5 AM
37°F
Mostly cloudy
Tomorrow
6 AM
35°F
Mostly cloudy
Tomorrow
7 AM
37°F
Mostly cloudy
Tomorrow
8 AM
41°F
Mostly sunny
Tomorrow
9 AM
46°F
Partly sunny

7 Day Forecast

Mostly cloudy

Wednesday

68 °F

A morning shower in spots; otherwise, clouds and breaks of sun


Thunderstorms

Wednesday Night

35 °F

A thunderstorm in spots this evening; otherwise, mostly cloudy


Intermittent clouds

Thursday

63 °F

A blend of sun and clouds


Mostly cloudy

Thursday Night

39 °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