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In Brief:
Our next storm is moving in with temperatures just at freezing at storm start rising to 40F during the height of the precipitation. Again, not a good recipe for a snow storm. Snow (and rain) could start as early as 6am, but will really get underway from 9am to 5pm. We have dry weather and warming temperatures through Saturday then another weather-fly my get in our ointment.
Update 9:30pm 10/6:
My rain gauge in NE Longmont received 1/10th of an inch of rain. I didn't see any snow fall (even at the end of yesterday's event). Now we warm up for a Christmas-light-hanging nice Saturday with temperatures 10-15F above normal (Figure 2 update). Our Sunday to Monday 'storm' is also very minor with temperatures looking too warm for snow. The GFS doesn't put down any snow in town (Figure 3 update). More tomorrow!
End Update 9:30pm 10/6.
Update 10am 12/5:
A quick update- as showers are falling... the HRRR model (it updates every hour) doesn't show measurable snow in Longmont (Figure 1 update). We do get between 1/10th of an inch of rain to maybe 1/4th in inch though (Figure 2 udpate). The thinking seems to be that, due to the dryness of the atmosphere at the lower levels, , the rain evaporating as it falls will cool the atmosphere enough for snow to fall in the later stages of the storm this afternoon. It all ends by 6-7pm. Other models still show maybe a coating to 1/2 inch of snow. Stay dray and watch out for that slippery snow/ice already on the ground.
End Update 10am 12/5.
Forecast Discussion:
Late night Wednesday (Figure 1) our next storm is rolling through the desert southwest with high pressure departing Colorado. Moisture increases and a not-so-cold front slides over the state from the north to create cloudy skies and rain and snow (Figures 3, 4, 5). The best precipitation chances run from 9am - 5pm but could start between 5-6am and linger until 7-8pm (Figure 2). Most of the good snow hits the mountains to our west and distant southwest.
Snowfall Roundup:
The GFS (Figure 6) does give us a coating to almost 1 inch of snow out of this storm (but will it stick anywhere but on the existing snow and ice?).
The NAM (Figure 7) keeps the snow to the slightly higher elevations west of most of Longmont.
The GEM (Figure 8) maybe gives the west side a coating but only produces rain on the east side.
It does not look like you'll need to shovel this one.
The Longer Range Forecast:
We are mostly dry on Friday and warmer, then climb to the mid 50'sF Saturday (Figure 2). There is a Sunday-Monday system we'll need to watch, but one shouldn't get too excited about the next-next storm until the next storm is done.
