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000
FXUS65 KBOU 080526
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1126 PM MDT Wed Jun 7 2023

.UPDATE...
Issued at 832 PM MDT Wed Jun 7 2023

Showers and a few storms continue to move NW mainly west of a New
Raymer to Fort Morgan to Limon line. Appears to be some type of
weak mid level circulation in water vapor imagery over east
central CO. based on current trends some of this activity may
back build into portions of the I-25 Corridor before ending.

UPDATE Issued at 712 PM MDT Wed Jun 7 2023

Threat of flash flooding in the burn scars has diminished so
have canceled the watch that was in effect.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 227 PM MDT Wed Jun 7 2023

Radar shows scattered thunderstorms continuing over the high
country with a continued concern for flash flooding over the burn
areas. Ample moisture continues to be transported into the region
resulting in above normal precipitable water values. SPC
mesoanalysis shows values in the 0.5-0.7 range over the high
country this afternoon. Storms are quite notably moving very slow,
which is no surprise given the weak steering flow aloft. Storms
will be capable of producing localized heavy rainfall. This will
support the continued threat for flash flooding over the burn
areas, thus the Flash Flood Watch will continue through this
evening for portions of north/central high country. Scattered,
lower coverage showers and storms are possible over the plains
later afternoon/early evening, some potentially containing small
hail, brief heavy rain, and gusty winds. Storms weaken and move
eastward mid-late evening.

Thursday, a broad trough remains off to the west with weak flow
aloft. Above normal moisture and marginal instability will support
afternoon scattered showers/storms in the high country with a
chance for scattered storms to spread onto the adjacent
plains/Palmer Divide and eventually eastward. Coverage trends
less than Wednesday over the high country with weak synoptic
subsidence in place. Storms will still be capable of brief heavy
rain, small hail, gusty winds. Given weak flow and moisture, a
flash flooding threat exists, although lower than Wednesday. Highs
in the 70s across the plains and 50s/60s for most of the high
country.

.LONG TERM...(Thursday night through Wednesday)
Issued at 227 PM MDT Wed Jun 7 2023

Not much adjusting planned in the extended period. Temperatures
will remain below normal through the middle of next week. Thursday
night and Friday, the blocking ridge will continue over the
central U.S. with light mid and upper level winds over CO. Similar
temperatures expected with enough moisture around for a persistent
chance of thunderstorms. Thursday night the best chance of storms
will be over the high terrain, then the focus will shift more to
the plains on Friday. GFS/NAM12 Layer Precipitable Water (PWAT)
values will range from 0.40-0.50 inch in the mountains, 0.50-1.0
inch across the plains.

Over the weekend,  the ridge remains over the central U.S. but it
starts to get widdled away to some degree by trough on each side,
one over the Southwest/Great Basin and the other over the Great
Lakes region. An upper level disturbance dropping down the east
side of the ridge is still expected to bring a cold front into the
northeast plains on Saturday. Northeast/east post frontal winds
will allow for the focus of showers and thunderstorms to shift
back into the foothills and Palmer Divide. The coolest and wettest
day on the weekend will be Sunday. Model PWAT values will
increase: 0.50-0.80 inch in the Front Range mountains/foothills,
0.8 to 1.25 inches across the plains. Locally heavy rain and the
potential for flash flooding will continue due to persistently
higher moisture and slow storm motions.

Next week, the ridge finally weakens enough to allow trough over the
Desert Southwest to move across CO.  The upper level flow will
remain weak, disorganized and unsettled, with a good chance of
afternoon and evening thunderstorms expected each day.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1122 PM MDT Wed Jun 7 2023

Winds will be light tonight and will have typical drainage wind
directions. Weak rain showers can`t be completely ruled out
tonight but the chances of one crossing over a terminal are very
small. Winds will remain light during the day tomorrow. Afternoon
and early evening storms will form mainly over the Palmer Divide
and Cheyenne Ridge. It is unlikely that a storm moves over any of
the three terminals but it is possible. Gusty winds, small hail,
and a brief drop in ceilings would be the main impacts from a
thunderstorm. Skies will slowly clear tomorrow night with drainage
winds developing.

&&

.HYDROLOGY...
Issued at 227 PM MDT Wed Jun 7 2023

Limited threat for flash flooding over the burn areas Thursday.
Moisture remains in above normal ranges with instability building
in the afternoon to support scattered showers and thunderstorms in
the afternoon/early evening. However, coverage trends lower than
Wednesday due to drier weak subsident flow working in. Weak winds
aloft and storms capable of localized heavy rainfall will still
warrant a limited threat the burn areas.

On Friday, the threat of flash flooding will be limited in the
burn scars as the best thunderstorm coverage may shift to the
plains. Over the weekend, a cold front will push into the
northeast plains and settle along the higher terrain. This will
increase the coverage of showers and thunderstorms back over the
burn scars, with elevated risk possible especially for Cameron
Peak and possibly Calwood.

&&

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

$$

UPDATE...RPK
SHORT TERM...Mensch
LONG TERM...Cooper
AVIATION...Danielson
HYDROLOGY...Mensch/Cooper