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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 68 °
• Low: 45 °
• Chance of Rain

• Thursday
• 
• High: 64 °
• Low: 39 °
• T-Storms

• Friday
• 
• High: 59 °
• Low: 37 °
• Mostly Cloudy

• Saturday
• 
• High: 59 °
• Low: 41 °
• Chance of Rain

• Sunday
• 
• High: 66 °
• Low: 41 °
• Chance of Rain

Area forecast discussion 
National Weather Service Billings Montana 
336 PM MDT Tuesday may 22 2012 


Short term...valid for Wednesday and Thursday... 


Scattered showers and some thunderstorms moving across the 
forecast area this afternoon as expected. Left exit region of 
upper jet nosing into Wyoming providing dynamic support with 
shallow 700mb trough in the mean flow also helping. We will 
see some downward motion behind these features work into the 
northwest zones around Wheatland this evening as the showers 
continue across the east and south. Yet another wave within the 
mean cyclonic flow will drop into southwest Montana late tonight 
and begin to affect the absaroka/Beartooth Mountains again by 
sunrise. Forecasts depict decent frontogenesis over the western and 
southern zones through the day with moist unstable cyclonic flow 
in the middle levels. Most of this activity will be showers...but 
there is still enough cape along the Wyoming border...and perhaps 
back into the central zones for an isolated thunderstorm Wednesday 
afternoon. Will keep low probability of precipitation over the forecast area Wednesday 
night simply due to the moist cyclonic flow...but the loss of any 
heating and notable forcing will prevent widespread convection 
overnight. 


Thursday becomes more interesting. The entire region will be 
under broad cyclonic flow with an upper low extending from 
southern Saskatchewan to the Hudson Bay...and another strong 
upper low tracking through the Pacific northwest and dropping 
south along the West Coast. This will place our forecast area in 
a deformation zone. In the meantime...a cold front is prognosticated to 
drop south from Canada into our forecast area by late Thursday 
afternoon. Cross sections have consistently indicated significant 
upslope flow into the foothills and eastern slopes of the 
beartooths with this system. So will hit the eastern slopes probability of precipitation a 
bit harder Thursday evening. Snow levels will be tricky as the 
850mb temperatures forecasts have been bouncing around and stubbornly 
not getting the coolest air very far south on the most recent 
European model (ecmwf). Best chance of snow will be above 5000ft...but the 
possibility of some mixed with rain at lower elevations is still 
plausible. Certainly expect the Nye to Red Lodge area to see some 
snow. Friday into Saturday night may see a better chance of snow 
accumulation in the foothills...see the extended discussion below. 
Bt 






Long term...valid for Friday...Sat...sun...Mon...Tue... 


The extended forecast appear to be in pretty good shape for the 
most part...favoring a cool and wet Holiday weekend and early 
week. Models have come back into agreement on amplified solution 
to upper low moving across the region...and indicate significant 
precipitation...and snow in the mountains. 


The upper level low pressure system will lift north into the 
region on Friday...and dominate the pattern through early 
Sunday...as upper level high pressure system centered in the 
southeast Continental U.S. Blocks eastward progression. This supports a deep 
southerly diffluent flow over the area through Saturday. A surface 
low also develops over Wyoming supporting the development of 
strong isentropic lift in the lower levels. Easterly surface flow 
will also setup upslope into area mountains and foothills. Have 
increased probability of precipitation slightly in upslope regions and in the higher 
terrain somewhat. Snow will be a concern...especially for the 
high terrain....early Friday morning and and again Friday 
night...as cold air pushes into the area. Most recent cross 
sections indicate 0c levels even lower than previously 
advertised. Therefore rain/snow mix may be possible in klvm and 
kbil Friday night...with significant accumulating snow in the 
high terrain...and some accumulation possible in Red Lodge and 
similar elevations. The low lifts north and east out of the 
region Sunday...but looks like it is slow moving enough at this 
time to keep precipitation in the region through the morning and 
afternoon. Downslope flow looks like it should kick in to clear 
out the area by Sunday evening. Have cooled temperatures for Friday 
through Sunday...in response to extensive precipitation/cloud 
cover...and cold air advection. 


Models diverge a bit on how they handle the remainder of the 
period...with ec remaining somewhat zonal and keeping lingering 
probability of precipitation through Monday night...with another trough into the area by 
Tuesday night. GFS supports a quick return to shallow ridging for 
Monday...but also brings another trough through the region Tuesday 
evening. Have maintained slight probability of precipitation through the period...with 
slight increase for Tuesday. Have continued warming trend through 
the remainder of the period...but cooled temperatures slightly 
throughout the period...with potential for continued scattered 
cloud cover and showers. Aag 




&& 


Aviation... 


Scattered showers and isolated thunderstorms have spread across 
much of south central and southeast Montana this afternoon...and 
are expected to continue into tonight. VFR conditions continue to 
prevail...but MVFR conditions are possible in heavier precipitation 
through the day. Prevalent MVFR conditions are expected to develop 
later this evening...as ceilings lower. Mountains will eb mainly 
obscured through today...and overnight. Aag 


&& 


Preliminary point temp/pops... 


Wednesday Thursday Friday Sat sun Monday Tuesday 
----------------------------------------------------------- 
bil 046/062 042/058 038/051 039/052 037/061 040/067 044/068 
54/T 34/west 45/T 76/T 54/T 22/T 22/west 
lvm 039/055 034/053 033/047 033/050 029/057 034/065 035/066 
44/T 35/west 56/T 66/T 65/T 22/T 33/west 
hdn 045/064 042/060 037/054 040/057 038/063 040/068 043/071 
63/T 44/west 45/T 66/T 54/T 32/T 22/west 
mls 049/066 044/061 038/054 042/057 040/063 041/068 043/071 
42/west 23/west 34/T 65/T 54/T 32/T 22/west 
4bq 048/064 043/060 039/053 043/060 039/064 040/070 042/073 
42/west 22/west 34/T 75/T 54/T 32/T 22/west 
bhk 047/064 041/062 035/055 043/055 040/065 040/068 041/071 
41/north 23/west 34/T 65/T 54/T 32/T 22/west 
shr 043/060 039/055 035/052 038/058 036/061 036/066 038/071 
44/T 33/west 45/T 86/T 63/T 22/T 22/west 


&& 


Byz watches/warnings/advisories... 
Montana...none. 
Wyoming...none. 


&& 


$$ 
Weather.Gov/Billings