Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 240126 CCA
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
621 PM MST Thu Nov 23 2017

.UPDATE...
Issued at 617 PM MST Thu Nov 23 2017

Getting some strong winds just outside of northern Carbon County
at Camp Creek RAWS and these winds are forecast to increase this
evening. Also getting gusts to 58MPH at Herrick Lane and Rock River
in the Laramie Valley. Went ahead and added northern Carbon and
Albany Counties to the High Wind Warning and started the Laramie
Valley zone now. Updates have been sent.

&&

.SHORT TERM...(This evening through Saturday Night)
Issued at 233 PM MST Thu Nov 23 2017

Tonight...Primary challenge will be the winds. Winds have already
begun to increase over our wind prone locations and with
strengthening gradients at the surface and aloft, we have decided to
begin the high wind warning early this afternoon. After midnight,
the NAM forecasts 700 mb winds to increase to 50 to 70 knots along
Interstate 25, with boundary layer showing near 50 knots. This
combined with decent subsidence should allow for some of the
stronger winds to mix down to the surface late tonight at Douglas,
Wheatland, Laramie and Cheyenne, so we have upgraded to a high wind
warning for the I-25 corridor and the Laramie Valley.

Friday...Fast moving shortwave trough aloft and its associated cold
front sweep across, producing a cooler day, albeit still relatively
mild for this time of year. With orographics, expect a chance of
showers over and near our Northern Laramie, Snowy and Sierra Madre
Ranges.

Friday night...Cooler night on tap with less wind and in the wake of
the cold frontal passage.

Saturday...Slightly cooler day with some thickness cooling and some
more cloud cover. Gradients suggest breezy to windy conditions
across southeast Wyoming.

Saturday night...Not as cold as Friday night as the airmass
moderates and with slightly more wind.

.LONG TERM...(Sunday through Thursday)
Issued at 233 PM MST Thu Nov 23 2017

Highly amplified upper air pattern returns to start the weekend
with strong ridging building over the Rockies through Sunday.
Southeast Wyoming will flirt with 580 dm heights at H5 and +8 C
temps at H7 by Sunday which should result in near record temps
once again especially over the plains. Still quite a spread
between the operational GFS and EC regarding the next strong upper
trough progged to cross the area from the west early next week.
GFS is much faster with the trough, keeping it an open wave while
driving a strong Pacific cold front through the area on Monday.
The EC is much slower and stronger, actually closing off the mid
level low over southern CO for a time on Tuesday. Don`t see much
support for the EC solution in the ensemble guidance and think the
pattern probably favors the more quickly ejecting and northern
system given the stronger jet energy downwind of the trough axis.
Should have a quick shot of mountain snow with the potential for
yet another wind event on Monday, this time more of a bora type
event with the strong cold frontal passage. Ridging builds in once
again behind this system for mid week, keeping us in a warm and
dry pattern.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 617 PM MST Thu Nov 23 2017

VFR with strong winds across our southeast Wyoming airports
through 18Z.  Winds should ease some afternoon, but slowly.

&&

.FIRE WEATHER...
Issued at 233 PM MST Thu Nov 23 2017

Minimal concerns based on projected winds and humidities.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until noon MST Friday for WYZ104>106-110-
     115>117.

     High Wind Warning from 2 AM to noon MST Friday for WYZ101-107-
     118.

NE...None.
&&

$$

UPDATE...GCC
SHORT TERM...RUBIN
LONG TERM...DEL
AVIATION...GCC
FIRE WEATHER...RUBIN
FXUS65 KCYS 052034
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
234 PM MDT FRI JUN 5 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 210 PM MDT FRI JUN 5 2015

THE MAIN CONCERNS LATE THIS AFTERNOON AND EVENING IS THE THREAT OF
SEVERE THUNDERSTORMS ALONG WITH THE POTENTIAL FOR FLASH FLOODING.
FORTUNATELY THE ATMOSPHERE OVER MUCH OF THE CWA STABILIZED
FOLLOWING MORNING SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A
QUICK MOVING SHORTWAVE. IT WILL TAKE A FEW HOURS FOR THE BOUNDARY
LAYER TO DESTABILIZE BUT EXPECTING THUNDERSTORMS TO REDEVELOP LATE
THIS AFTERNOON. THE MODELS CONTINUE TO STRUGGLE SHOWING WHERE AND
WHEN STORMS WILL OR WILL NOT DEVELOP. MOST LIKELY THUNDERSTORMS
WILL DEVELOP ALONG THE LARAMIE THE LARAMIE RANGE LATE AFTERNOON
AND THEN SHOULD PUSH NORTHEAST INTO THE PLAINS DURING THE EVENING.
SHOULD ANY THUNDERSTORM BECOME STATIONARY OR BACK BUILD...FLASH
FLOODING THREAT WILL INCREASE...SUCH AS OCCURRED YESTERDAY. THE
FLOW ALOFT IS SOMEWHAT STRONGER...SO MOST LIKELY STORMS WILL NOT
REMAIN STATIONARY BUT COULD STILL SEE A FEW TRAINING THUNDERSTORMS.
MOST SHOWER AND THUNDERSTORM ACTIVITY WILL END BY MIDNIGHT BUT A
FEW THUNDERSTORMS MAY LINGER INTO THE OVERNIGHT.

.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 210 PM MDT FRI JUN 5 2015


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 210 PM MDT FRI JUN 5 2015



&&

.FIRE WEATHER...
ISSUED AT 210 PM MDT FRI JUN 5 2015

A BRIEF BREAK FROM THE WET PATTERN EARLY NEXT WEEK THEN CHANCES FOR
SHOWERS AND THUNDERSTORMS AGAIN BE MID NEXT WEEK. NO FIRE WEATHER
CONCERNS AT THIS TIME.


&&

.HYDROLOGY...
ISSUED AT 210 PM MDT FRI JUN 5 2015


&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR WYZ101>103-
     105>108-115>119.

NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...SML
HYDROLOGY...ZF



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