12/16: Monday SnowTalk for Late Week

What a BALMY Afternoon Central & S'Eastern WY experienced with Above Average Temperatures and breezy weather.  This pattern will persist through Tuesday and Wednesday ahead of our next Storm System sliding into Wyoming on Thursday. To preview the next two days:  what you experienced Monday is what you'll see for the next 48 Hours.


THURSDAY MORNING will be the initial start of the Snow System sliding from Montana into Northern WY.  Now, latest model guidance continues to show Light to Moderate snowfall for Montana but the Moisture decreases in Activity as it approaches the Bighorns and much of Northern WY. 

NAM at 5AM THURSDAY

<< You can see that the NAM has the Cold Front right on top of Riverton/Casper as the wind is shifted to the North. Light Snow is possible for the Bighorns & I-90.

** However, the GFS shows the Front a little farther North along the I-90 Corridor by 5AM with Snow likely in Southern MT.






THURSDAY LATE MORNING shows the Cold Front blasting through Central and now into S'Eastern WY as it slides in the Cheyenne area.  BOTH Models (NAM/GFS) show Snow breaking out with Accumulation likely.

NAM at 11AM THURSDAY

<< NOW, what I am closely watching is the potential for Light-maybe "Moderate Snowfall from Casper to Cheyenne along the Laramies.  A weak 1004mb Low in Northern CO could provide some "Weak Upslope Flow" for a couple Hours.  Moderate Snowfall is when you have Snowfall Rates up to 1"/HR.

** GFS shows the Same burst near Goshen/Platte Co's, so this will be a critical timeframe of who could see the HEAVIEST Snow.





THURSDAY EARLY EVENING shows a Broad swath of Light Snow all along Central & Southern WY.  Light Accumulations should continue to pile up along I-25 & I-80.

NAM at 5PM THURSDAY

<< NAM/GFS both show the same placement on the Snow.  What will occur later in the Evening is High Pressure building from the North into MT/Dakota's will slide into WY for the Overnight dropping our Temperatures after the Snow and Skies clear up.









LATE THURSDAY/EARLY FRIDAY shows different signs as our Confidence grows Weak.  NAM wants to move any Snow Chance away and clearing us out Faster.  However, the GFS is different in their Guidance as our Front stalls along I-70 in Colorado. A weak impulse forms and here's what I see (IMAGE BELOW)

<<  A weak Low forms in Northern UT/CO providing weak Upslope Flow along I-80.  Snow could continue longer from Evanston-Rock Springs-Rawlins so we have to "closely" watch this Feature with the Morning Data









SNOW AMOUNT FORECASTS:
 ** THESE ARE NOT MY FORECASTS; These are Model Guidance Snow Forecasts. However, these Models give me an Idea who/how much snow is possible **

1) Here is the Iowa St Meteogram showing the "Range" from Weather Models

Casper: 1-3.5"

** MANY Spots show Snow from the Meteogram of 1-3" such as: Laramie, Cheyenne, Sheridan, Rock Springs, Lander & Worland
-Riverton only has up to an Inch

NAM SNOWFALL MAP:

<< NAM paints a broad area of 6-8" just South of Casper/Alcova and along the Northern Laramies into Eastern WY.  However, an Isol'd 8-10" near Glendo & Guernsey.












GFS SNOWFALL MAP: 

<< GFS has that swath of 6-8" along I-80 from Rock Springs to Rawlins but light snow amounts along I-25.












THOUGHTS:  We are still over 2.5 Days away until the main event and still lots of questions remain from the Guidance that I'm not Sold On yet.  Hopefully the Morning Data and EURO data shows better guidance, but a New Post will be up Tomorrow Evening.