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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

Mostly sunny

Mostly sunny

61°F

UV Index
2 Low
Pressure
29.65 Falling
Visibility
5 miles
Dewpoint
58 °F
Humidity
89%
Wind
SW 1.6 mph
Gust
3.2 mph
Wind Chill
61 °F

Hourly Forecast

Today
8 AM
69°F
Mostly sunny
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9 AM
76°F
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10 AM
81°F
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11 AM
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12 PM
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Intermittent clouds
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3 PM
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4 PM
88°F
Mostly cloudy w/ t-storms
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5 PM
85°F
Intermittent clouds
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6 PM
84°F
Intermittent clouds
Today
7 PM
82°F
Intermittent clouds

7 Day Forecast

Partly sunny w/ t-storms

Saturday

92 °F

Warmer with intervals of clouds and sunshine; a thunderstorm around this afternoon


Mostly clear

Saturday Night

57 °F

Clear to partly cloudy


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Sunday

93 °F

Sunny to partly cloudy and very warm


Partly cloudy

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56 °F

Partly cloudy


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Monday

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Partly sunny and hot; breezy in the afternoon


Clear

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Windy in the evening; clear


Partly sunny

Tuesday

80 °F

Partly sunny and cooler; breezy in the afternoon with a thundershower in spots


Mostly cloudy

Tuesday Night

52 °F

Mostly cloudy with a shower in the area late


Cloudy

Wednesday

75 °F

A thunderstorm around in the morning; otherwise, cloudy


Intermittent clouds

Wednesday Night

55 °F

Partly cloudy with a stray thunderstorm late


Sunrise and Sunset

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5:30 AM
Sunset
8:32 PM

Based on AccuWeather data