Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 132130

Area Forecast Discussion
National Weather Service Denver/Boulder CO
330 PM MDT Tue Mar 13 2018

.SHORT TERM...(This evening through Wednesday)
Issued at 330 PM MDT Tue Mar 13 2018

Quiet weather continues in the short term with a high amplitude
ridge building across the Central Rockies through Wednesday.
Airmass is sufficiently dry to keep out any threat of
precipitation. Lows tonight will modify a few degrees with onset
of warm advection, and then highs on Wednesday will be close to 15
degrees warmer as 700 mb temps rise to +4C. That should boost
highs to around 70F across the plains, with 40s to lower 50s
mountains and high valleys. Winds will remain light with the high
pressure ridge and light winds aloft. Only some high clouds
spilling across the Front Range through the day.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 330 PM MDT Tue Mar 13 2018

The upper ridge starting out over eastern Colorado tomorrow
evening is forecast to be moved out of the state by a vigorous
digging trough over the western U.S. by Friday morning. This
trough looks like it is going to bring a good amount of Pacific
moisture and entrain additional moisture from the southern plains.
Each of the medium range models show the trough becoming
negatively tilted over time as the main upper low remains off the
Oregon Coast. As the trough becomes negatively tilted and taps
into the Gulf of Mexico moisture over the southern plains, a new
upper circulation will form and intensify over southeastern
Colorado. This will create a lot of dynamic forcing over eastern
Colorado through the day Thursday. By evening, model soundings are
showing some instability over northeast Colorado with moist
soundings. This should produce showers through the evening and
overnight. Ahead of that, the moisture from the Pacific will be
moving into the mountains, bringing an increase in precipitation
over the higher terrain. Snow levels will be starting out quite
high, above 10,000 feet Thursday afternoon, but then quickly
dropping. Snow amounts look like they will be in the 3 to 6 inch

By Friday morning, the developing upper low over southeast
Colorado is expected to be moving out over western Kansas. The
return flow on the back side of the low will cool down the airmass
and possibly changing rain over to snowfall as the storm moves
out. Weak upper level ridging downstream from the western U.S. upper
low will bring a return of quiet weather to Colorado.

This upper low is then forecast to be the next weather maker over
Colorado when it arrives on Sunday. This upper low looks like it
will also move over the state in a negatively tilted orientation,
producing another round of mountain precipitation and a chance of
showers out across the plains Sunday and Sunday night. Warmer
temperatures ahead of the trough will once again be replaced by
cooler air after the trough moves past. Rain on the plains will
once again have the chance to change over to snow Sunday night.

All in all it looks like a fairly active pattern is starting to
set up for the upcoming week.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 330 PM MDT Tue Mar 13 2018

VFR conditions will persist through Wednesday. East/southeast
winds around 8-14 knots will shift more southerly through 06Z and
then remain south/southwest through 15Z Wednesday. Then expect a
slow transition back to southeasterlies around 10 knots by
Wednesday afternoon.




SHORT TERM...Barjenbruch
LONG TERM...Dankers
AVIATION...Barjenbruch is the U.S. government's official web portal to all federal, state and local government web resources and services.