2/26: Wednesday's Evening Blog ~ Talking WARMTH then SNOW

Good Wednesday Evening Folks,

Thursday looks to be the "Warmth & Wind" before the Snow for Central & Eastern WY.

<< Mild & Breezy for the I-25 Corridor in the Afternoon as we'll stay Partly Cloudy.  

* MOISTURE from CA and Pacific will surge Eastward into NV/UT/ID and then impact Western WY late in the Evening with a "Light" Snow Chances.




WINTER STORM WATCHES are already out for a good chunk of Central, Northern and Western WY.  Here is what the NWS Riverton mentioned about this storm: "

A MAJOR WINTER STORM IS EXPECTED TO DEVELOP ACROSS THE AREA
THURSDAY NIGHT AND FRIDAY AND CONTINUE THROUGH SATURDAY NIGHT. THE
COMBINATION OF THREE STORMS SYSTEMS ARE EXPECTED TO COMBINE TO
FORM A HIGH IMPACT LATE WINTER STORM ACROSS THE AREA. THE WEST
WILL BE IMPACTED FIRST AS THE FIRST WEATHER DISTURBANCE MOVES IN
FROM THE WEST THURSDAY NIGHT AND LASTS INTO FRIDAY. AT THE SAME
TIME...AN ARCTIC COLD FRONT WILL MOVE SOUTH INTO FAR NORTHERN
WYOMING LATE THURSDAY NIGHT AND WORK SOUTH INTO CENTRAL WYOMING
DURING THE DAY FRIDAY. SNOW WILL DEVELOP BEHIND THIS SYSTEM ALSO.
A THIRD...MOIST AND POTENT STORM SYSTEM FRIDAY NIGHT AND SATURDAY
WILL COMBINE WITH THIS ARCTIC AIR TO PRODUCE A POTENTIALLY VERY
MAJOR STORM SYSTEM ACROSS CENTRAL WYOMING WITH SNOW CONTINUING
ELSEWHERE.

I am not Showing the Model Runs in this Blog Post this evening, but what I want to tell you is that this storm isn't showing signs of a classic Upslope Flow event.  This is a setup that shows Over-Running of moisture in a Zone or Band.  We call these Baroclinic Zones as Moisture can stream from UT/CO and surges Northward into WY. This zone can cause rising air to lift over Colder Air and surge Moisture ~ Isentropic Upglide.   (IMAGE BELOW)

- 3 of the 4 Weather Models (GFS/EURO/CANADIAN) still shows Moderate to Heavy Snow for Central and Eastern WY along the Laramies from Overnight Friday through Early Afternoon Saturday.  
- However, there is one Outlier; the NAM Model.  This shows much Drier Air as High Pressure eats away the Moisture, but only shows "Lighter Snow".  
  ** I will closely watch the Trends of each Model, any Fluctuations of themselves and any consistency between them through Friday Morning once the 1st Wave of Moisture spills in.  **



MODEL SNOW AMOUNTS:  **NOT A FORECAST **

This is the Canadian Model through 5AM Sunday:

-Casper: 6-12"
-Laramie Range: 12-16"
- Rest of Central WY: Anywhere from 2-6"

* Canadian Model has been fairly consistent with this Storm so we will closely see what it wants to spit out from Late Thursday through Sunday

<< This is the GFS Model Amount through 5AM Sunday.

Central WY: Over a Foot in Lower Elevations  along the I-25 Corridor

Laramie Range: 18"+

** Remember, the GFS has been very aggressive with this Storm for Central WY from Casper to Cheyenne along the Laramies.


METEOGRAM:   Here is the Iowa St Meteogram that shows Snow Amounts from different Weather Models.

< Casper's snow varies due to the NAM Model being Low, as the GFS shows the Higher Amounts.







Other Cities for Forecast Amounts via Meteogram ^
Lander: 3-7"
Sheridan: 3-6"
Gillette/Cheyenne: 2-4"
 Rock Springs/Laramie: 1-3"
Riverton: .5-1.5"


THOUGHTS:  As I looked at the Upper Atmosphere today about 10,000 Feet, you can tell where the Winds will be blowing from.  Its not a classic "dumping" of Snow for WY with the Upslope flow, but we could likely see that Isentropic (Southwest Flow) Lift.  Besides that, the Threat still exists for Moderate to Heavy Snows for Central & Southeastern WY along the Laramie Range.  A FOOT of Snow is still possible but once we head into Late Thursday and Early Friday, that is when we will have a better grasp of who can see how much.