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Fri Update: The Front Range Forecast: Snow totals, warm up

In Brief:

The warm up begins.

Friday update:

The storm delivered!  Longmont received over 2 inches of liquid and about 7-11 inches of snow in spots. Boulder saw 12-19 inches.

We warm up, melt off and dig out from here.

figure1u_03152024
Figure 1 update: the CoCoRaHS new snow report as of 7 am Thursday.
figure2u_03152024
Figure 2 update: the CoCoRaHS new snow report as of 7 am Friday.

End Friday update.

Forecast Discussion:

Winter Storm Warning

Issued: 8:13 PM Mar. 12, 2024 – National Weather Service

...WINTER STORM WARNING IN EFFECT FROM 9 PM WEDNESDAY TO 6 AM MDT FRIDAY...

* WHAT...Heavy snow expected. Total snow accumulations between 9 and 18 inches. Winds gusting as high as 35 mph.

* WHERE...Boulder and the western suburbs of Denver, and Denver.

* WHEN...From 9 PM Wednesday to 6 AM MDT Friday.

* IMPACTS...Travel could be very difficult to impossible. The hazardous conditions could impact the Wednesday evening and Thursday morning commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. The latest road conditions for

Colorado can be obtained by calling 5 1 1 or by going to www.cotrip.org.
________________________________________________________________________

We have the warmth before the storm. Finally, it looks like a major winter storm is on its way. It should be the biggest of the year (channel 9 said the biggest in 3 years). We might hear some thunder early Wednesday morning, with a break in the action Wednesday morning with rain chances picking up again in the afternoon. Any rain that falls should change over to snow around 8pm (but could wait as long as the pre-dawn hours).  If it does change to snow in the evening, then top snow totals are expected. (Figure 1)

It is looking more likely that most of I-25 south of Ft. Collins and especially the Denver Metro will get to or exceed a foot of snow. Snow tapers off early morning Friday.

The system is powered by a slow moving cut-off low that will roll by (Figure 2). The central mountains might pick up areas of 32-46 inches of snow (Figure 3). The pre-snow rain isn't looking very impressive, currently - maybe 0.1-0.25" of water (Figure 4) at the lower elevations. Matt Makens's map from weather5280 12-24" for Boulder and 6-12" for western Denver (Figure 5).  Note: the trend in the models is for even more snow to fall forecast after forecast. I'll update as needed.

Snowfall roundup for Longmont:

Weather5280:   10.9"
The GFS:        14-16"
The NAM:       16-18"
The Canadian: 10-12"
Channel 9:       6-12"
Channel 7:        7"
My forecast:    7-14"

 

figure1_03122024
Figure 1: the 10 day graphical forecast for Longmont from weatherunderground.com
figure2_03122024
Figure 2: the 500mb upper air forecast map from the GFS and tropicaltidbits.com
figure3_03122024
Figure 3: the 3 day 10:1 snowfall forecast from the GFS and weather5280.com
figure4_03122024
Figure 4: the 3 day precipitation (and snow melt) forecast from the GFS and weather5280.com
figure5_03122024
Figure 5: the weather5280.com// Matt Makens snowfall forecast from this storm.

The Long Range Forecast:

For the weekend and beyond, we warm up and dig out.


About the Author: John Ensworth

John Ensworth used to work from Longmont as the PI for the NASA through the IGES (The Institute for Global Environmental Strategies). He now teaches technology, algebra, astronomy, meteorology, film school, and Lego robotics to middle/high school.
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Current Weather

Sunny

Sunny

57°F

UV Index
6 High
Pressure
30.01 Steady
Visibility
8 miles
Dewpoint
45 °F
Humidity
63%
Wind
NE 2.2 mph
Gust
4.9 mph
Wind Chill
57 °F

Hourly Forecast

Today
11 AM
60°F
Intermittent clouds
Today
12 PM
61°F
Intermittent clouds
Today
1 PM
63°F
Intermittent clouds
Today
2 PM
64°F
Mostly cloudy w/ t-storms
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65°F
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Today
4 PM
63°F
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5 PM
61°F
Intermittent clouds
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6 PM
59°F
Intermittent clouds
Today
7 PM
56°F
Intermittent clouds
Today
8 PM
53°F
Cloudy
Today
9 PM
51°F
Cloudy
Today
10 PM
49°F
Cloudy

7 Day Forecast

Partly sunny w/ t-storms

Thursday

65 °F

Intervals of clouds and sunshine with widely separated thunderstorms this afternoon


Thunderstorms

Thursday Night

44 °F

A thundershower in spots this evening; otherwise, overcast


Thunderstorms

Friday

51 °F

A thick cloud cover and cooler; a passing shower in the morning followed by a thunderstorm in parts of the area in the afternoon


Mostly cloudy

Friday Night

45 °F

Low clouds breaking


Mostly cloudy w/ t-storms

Saturday

75 °F

Variable cloudiness with a thundershower; warmer


Clear

Saturday Night

43 °F

Clear


Partly sunny

Sunday

82 °F

Very warm with sunshine mixing with some clouds; elevated fire risk due to gusty winds and low humidity


Mostly clear

Sunday Night

46 °F

Mainly clear


Mostly cloudy

Monday

61 °F

Turning cloudy and cooler; a shower in spots in the afternoon


Intermittent clouds

Monday Night

39 °F

Clearing


Sunrise and Sunset

Sunrise
6:10 AM
Sunset
7:48 PM

Based on AccuWeather data