Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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000
FXUS65 KBOU 291742
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1142 AM MDT Thu Sep 29 2016

.UPDATE...
Issued at 1114 AM MDT Thu Sep 29 2016

Pretty decent moisture stream moving north-northeast right not on
the satellite pictures. It is still mostly west and southwest of
the CWA currently. Will make appropriate adjustments to GFE sky
cover grids. There is precipitation with the moisture on the
radars upstream of the moisture. Will leave alpine pops alone
with this update

&&

.SHORT TERM...(Today and tonight)
Issued at 437 AM MDT Thu Sep 29 2016

Upper level ridge axis over eastern Colorado early this morning
will shift slowly eastward through tonight. As a result, flow
aloft turns south/southwesterly, allowing mid and upper level
moisture to spread across the forecast area. The majority of the
deeper moisture plume as seen in the water vapor and IR imagery is
moving nearly due north across western Colorado and will continue
to do so today as advertised in the specific humidity progs. That
will keep the best chance of showers and afternoon thunderstorms
to our west, but still expect isolated to scattered coverage to
develop over portions of our mountains from Summit county
northward this afternoon and evening. Not sure if anything will
even make it into the foothills given the high amplitude ridge and
southerly flow, while the plains should stay dry with a drier and
slightly more stable airmass in place. Winds will increase across
the plains and lead to increased grassland fire danger, but
humidities high enough to preclude any highlights. Temperatures
expected to be similar to those observed yesterday.

For tonight, will keep some threat of precipitation lingering in
the mountains but any precip would be light. Plains expected to
remain dry without sufficient synoptic scale forcing.

.LONG TERM...(Friday through Wednesday)
Issued at 437 AM MDT Thu Sep 29 2016

Weather on the plains will continue to be warm through about
Monday as southwesterly flow aloft and an upper ridge continue
over the state. Mountain areas will see increasing moisture which
could produce afternoon showers over the weekend. The plume of
increasing moisture is already evident on satellite imagery over
northwest Mexico and Arizona this morning. Medium range models are
in good agreement through the weekend as the upper ridge over
Colorado gradually moves eastward ahead of a vigorous trough
moving into the Great Basin by Monday morning. The 00z model runs
had continuing agreement early next week as the upper trough
tracked northeastward across Wyoming through the middle of the
week. The 06z run of the GFS now shows the upper trough moving to
southeast Colorado by Tuesday night. Will have to wait and see if
any other successive runs follow this track before changing the
forecasts. For the time being, will stick with the trend of most
precipitation occurring over the mountains through the weekend
with just a few periods of isolated showers on the plains early
next week. Regardless of the eventual track of the upper trough
next week, a fair shot of cold air will accompany the weather
system which is going to cool things down across the northern half
of the state from Monday night through Wednesday. Snow will be
possible in the mountains during this time frame. Across northeast
Colorado, next Tuesday and Wednesday could only see highs in the
lower 60s. But then again, it will be the first week of October.
Summer can`t last forever.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1114 AM MDT Thu Sep 29 2016

Weak northeasterly winds are expected to become easterly by mid
afternoon then southeasterly by later afternoon. Normal drainage
patterns are expected by 03Z. Ceiling issues are not expected.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...RJK
SHORT TERM...Barjenbruch
LONG TERM...Dankers
AVIATION...RJK


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