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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – November 14, 2017

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

Forecast Discussion:

While incredibly awesome weather rolls on, we finally have a storm to focus on.  But first the amazing warmth Monday can be seen in Figure 1 - oranges are how 'above average' the temperatures were. Longmont is around 15F up.  We'll be nice again today (Tuesday) but a dry cool front is on the way.  Figure 2 shows the front just past Longmont 6pm Tuesday.  Figure 3 has the front far to the south by 6am Wednesday.  Note, there is no precipitation to be seen.

Figure 1: The departure from normal surface temperatures from Monday evening.

Figure 2: The NCEP surface analysis forecast for Tuesday PM.

Figure 3: The NCEP surface analysis forecast for Wednesday AM.

The longer range forecast:

But there IS a storm coming.  It is still not impressive (for Longmont), but it is something! Figure 4 is the upper air map for Friday early morning. There is a broad trough over Colorado with embedded short wave troughs (red lines). The ridges are far to the west and east (blue lines.

The GFS precipitation forecast (rain and melted equivalent of water from snow, ice etc.) in Figure 5 shows the mountains to our west getting some nice water.  Figure 6 shows the western slopes and north and central mountains getting some good snow... but Longmont (in this run) is on the edge of nothing - rain or snow.  The gap along I-25 is the result of down slope during the storm what will warm us to the edge of snow/rain AND inhibits precipitation.  Right now, Longmont only gets a trace of something wet Thursday PM into Friday AM, but we'll watch for changes as the week goes on.   Maybe you should go wash your car and leave it out at the end of the week... I'm just sayin'.

Figure 4: The GFS 500mb upper air analysis forecast map for Thursday PM/Friday AM.

Figure 5: The GFS forecast total precipitation map from Monday PM to Friday PM. Longmont = pink dot.

Figure 6: The GFS forecast total snow map from Monday PM to Friday PM. Longmont = pink dot.

Current Weather

Cloudy

Cloudy

54°F

UV Index
0 Low
Pressure
29.89 Rising
Visibility
8 miles
Dewpoint
35 °F
Humidity
50%
Wind
NW 3.3 mph
Gust
8.9 mph
Wind Chill
54 °F

Hourly Forecast

Today
11 PM
49°F
Mostly 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
Tomorrow
10 AM
50°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 parts of the area 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