wxgeek's weather-Sunday Storm Forecast-Update 4/13 1:30pm

-Sun Apr 13

update 1:30 pm - heaviest snow just moving into western CO at this time with mid level circulation over soutwhest CO. As this circulation moves east today, snow will increase over eastern CO. Temps continue to drop. Latest model guidance shows slightly lower sonowfall totals, with highest amount limited to northern mountains and northern foothills. I believe our foothills will see 5-10 inches most locations, with up to 12-14 inches in favored locations. Heaviest snow looks to be from 2 pm to 9 pm today, diminishing after midnight. Most paved roads remaning wet, but believe with heavier snow and temps dropping will become snow and ice packed after 3-5 pm.

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Sun Apr 13

Snow has arrived on schedule, with precip turning to all snow along the Urban Corridor a little ahead of schedule. Snow becomes moderate to heavy this morning into this evening, then begins to diminish tonight. Snow may linger into early Monday morning. Amounts still on track with 8-16 inches in mountains and favored foothill areas, with 4-10 inches for Urban Corridor and lower foothills, and 2-8 inches for adjacent plains. Roads currently wet, but will become ice and snow packed this afternoon into Monday morning, so pretty tough Monday morning commute in store.

Cinnamon rolls and green chile eggs are baking, so a relaxing Sunday on tap.

Models in decent agreement that we will see additional precip Wednesday into Thursday morning, with snow level down to near plains level. Amounts currently look to be in the 2-6 inch range above 7000 ft. Easter weekend still looking mostly dry and warm.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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Sat Apr 12

Lots of clouds this morning associated with first upper trough to our southwest. This system will pass south of CO today and bring only isolated showers to our state. Showers most likely across the southwest, central and south central mountains, but some could develop over the foothills and plains this afternoon and evening with a few isolated thunderstorms. Generally less than 0.10 inches expected with snow level at or above 12,000 ft.

Attention then turns to stronger upper trough moving down from the northwest. Models consistent in track and timing of this system and dig it across eastern UT Sunday and then across CO Sunday night. This is a favorable track for snow across CO as surface low develops in southeast CO. Associated cold front will move from north to south and pull moist northeast upslope flow behind front. Snow looks to begin north of I-70 early Sunday morning, between 3 am and 6 am. Snow moves south to the Palmer Divide by 6 am to 9 am and then persists into early Monday morning. Heaviest snow looks to be from about 9 am Sunday through midnight, with snow lingering into Monday morning til about 6 am. Snow level begins at 7000-8000 ft at 6 am Sunday morning, but will lower as front moves south, so down to around 5000-6000 ft by Noon, and down to plains level afterwards. Heaviest snow will be in the northern and central mountains as well as foothills and Palmer Divide for areas above 7500 ft. Lower elevations will see early rain, and have much of the initial snow melt on contact with warm ground surfaces, but will eventually accumulate snow Sunday afternoon into Sunday night. For storm totals, I have looked at all model output, the NAM, WRF, GFS and ECMWF and as usual each has their bias with the GFS being the wettest, and NAM being the driest. Here is my thinking:

Northern and Central Mountains: 6-14 inches
Foothills and Palmer Divide above 7500 ft: 5-12 inches
Lower Foothills and Urban Corridor: 3-7 inches
Plains: 1-4 inches

Roads above 7500 ft will become snow and ice packed by Sunday afternoon into Monday morning. Roads below will be wet and slushy, with some ice and snow pack possible Monday morning, hence expect the Monday morning commute to be slow and slick with the usual roll overs and accidents. Snowfall rates could be 1-2 inches per hours at times on Sunday, so no matter how many plows are out, they will not be able to keep up with snowfall rates.

By Monday, conditions clear and temps warm but will remain below seasonal norms with snow on the ground, but lots of melting with April sun. Roads should be fine by Monday evening commute.

For the remainder of next week, GFS and ECMWF still at odds. GFS brings another potent system into CO late Wednesday into Thursday with more snow down to plains level, while the ECMWF has some precip, but is much warmer. Will have to wait and see how this evolves. Instincts lean towards the ECMWF solution. Both models now keep Easter weekend dry and warm.

I hope everyone is able to get out and enjoy the day today before our potentially biggest storm of the year rides through on Sunday. Be safe traveling on Sunday and Monday morning, and please remember to turn your lights on when it's snowing so other drivers can see you.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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Bump for 4/13 update

Bump for 4/13 1:30 pm update