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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – May 15, 2019

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

In Brief:

Temperatures 15-20F above normal are the norm for a couple more days with high pressure stacked up through the atmosphere. Friday, a deep trough moves in kicking off storms and cooling us to below normal levels and returning a chance of rain for much of next week.

Forecast Discussion:

We have high pressure over the state today and weak winds (Figure 1). Overhead in the upper atmospheric map (Figure 2) the center of the ridge line is almost overhead. This will past to the east today changing the flow aloft from northwest flow to a southwest flow. That changes the drift direction of the afternoon storms that move off the mountains and warms us a bit more (Figure 3). There is a chance of afternoon thunder showers everyday around time of maximum heating (2-5pm).

The Longer Range Forecast:

Friday we see the change occur with a deep trough moving in from the west (red line digging towards us in Figure 4). We'll keep an eye on the amount of moisture that can make it in by Friday to see IF we may see severe weather nearby (Figure 3). From Saturday on into next week we hover in the 60'sF for highs with many chances for rain again. More later!

Figure 1: The forecast surface map for Wednesday PM from NCEP.
Figure 2: NCEP 500 mb upper air map from Tuesday PM. Blue lines are ridges, red lines are troughs.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 4: The 500mb forecast upper air analysis for Wednesday morning. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Current Weather

Rain

Rain

48°F

UV Index
0 Low
Pressure
29.72 Rising
Visibility
7 miles
Dewpoint
44 °F
Humidity
84%
Wind
NNE 4.2 mph
Gust
8.3 mph
Wind Chill
47 °F

Hourly Forecast

Today
8 PM
56°F
Thunderstorms
Today
9 PM
53°F
Thunderstorms
Today
10 PM
50°F
Thunderstorms
Today
11 PM
48°F
Thunderstorms
Tomorrow
12 AM
46°F
Cloudy
Tomorrow
1 AM
46°F
Cloudy
Tomorrow
2 AM
45°F
Cloudy
Tomorrow
3 AM
44°F
Rain
Tomorrow
4 AM
44°F
Cloudy
Tomorrow
5 AM
44°F
Rain
Tomorrow
6 AM
44°F
Rain
Tomorrow
7 AM
44°F
Rain

7 Day Forecast

Mostly cloudy w/ t-storms

Friday

69 °F

Variable cloudiness with a couple of thundershowers this afternoon; gusty winds and small hail can accompany any downpour


Thunderstorms

Friday Night

41 °F

Cloudy; a couple of showers and a thunderstorm this evening followed by periods of rain late; gusty winds and small hail can accompany any downpour


Rain

Saturday

44 °F

Chilly with periods of rain and a thunderstorm; travel in the foothills and mountains will be slippery due to snow


Rain and snow

Saturday Night

36 °F

Cloudy with rain, mixed with a little snow late; travel in the foothills and mountains will be slippery due to snow


Mostly cloudy

Sunday

61 °F

Mostly cloudy and warmer


Intermittent clouds

Sunday Night

36 °F

A thunderstorm in spots in the evening; otherwise, partly cloudy


Partly sunny

Monday

71 °F

Partly sunny, pleasant and warmer


Partly cloudy

Monday Night

45 °F

Partly cloudy


Mostly sunny

Tuesday

73 °F

Pleasant with sunshine and patchy clouds


Partly cloudy

Tuesday Night

40 °F

Partly cloudy


Sunrise and Sunset

Sunrise
6:06 AM
Sunset
7:51 PM

Based on AccuWeather data