Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 190414
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1014 PM MDT Mon Mar 18 2024

.KEY MESSAGES...

- Well above average temperatures with dry conditions are
  expected throughout most of the week.

- Precipitation chances increase towards the end of the week.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 310 PM MDT Mon Mar 18 2024

A VERY PLEASANT DAY HAS TAKEN HOLD OF THE REGION AS SURFACE HIGH
PRESSURE AND SPRING-LIKE TEMPERATURES REMAIN THROUGH THE EARLY
AFTERNOON HOURS. SURFACE OBSERVATIONS RANGE FROM THE LOWER 50S TO
MIDDLE 60S EAST OF THE LARAMIE RANGE. THIS IS ON THE ORDER OF 10 TO
EVEN 20 DEGREES WARMER IN SOME LOCATIONS COMPARED TO THIS TIME
YESTERDAY. FURTHER WEST OF THE LARAMIE RANGE, DAYTIME HIGHS IN THE
30S AND 40S ARE PRESENT, WHICH IS APPROXIMATELY 5-10 DEGREES WARMER
THAN 24 HOURS PREVIOUSLY. SURFACE FRONTAL ANALYSIS DEPICTS A WEAK
WARM FRONTAL BOUNDARY DRAPED ALONG A NORTH TO SOUTH TRANSECT FROM
THE NORTHERN PLAINS DOWN TO THE TEXAS PANHANDLE. TAKING A LOOK AT
GOES-16 SATELLITE WATER VAPOR IMAGERY, AN AMPLIFIED UPPER LEVEL
RIDGE RESIDES ALONG PACIFIC COASTLINE, AND ELONGATING OVER THE GREAT
BASIN AND INTERMOUNTAIN WEST, WITH THE CUT-OFF UPPER LEVEL LOW
CENTERED NEAR THE BAJA CALIFORNIA REGION. THE AFOREMENTIONED UPPER
LEVEL RIDGE IS WHAT`S RESPONSIBLE FOR THE ABOVE AVERAGE TEMPERATURES
ACROSS OUR CWA.

THIS TREND OF ABOVE AVERAGE TEMPERATURES WILL CONTINUE TO REMAIN
PRESENT FOR MOST OF THE CWA ON TUESDAY AND WEDNESDAY. WIND AND WIND
GUSTS WILL NOT BE AN IMPACT AS RELATIVELY TOLERABLE WINDS REMAIN
PRESENT FOR WYOMING AND WESTERN NE STANDARDS. THIS IS DUE TO A
MODIFIED AIR MASS REMAINING PRESENT ACROSS OUR CWA THE NEXT SEVERAL
DAYS. THE SURFACE WARM FRONTAL BOUNDARY TO OUR EAST, AS OF MONDAY
AFTERNOON, WILL BECOME A STATIONARY FRONTAL BOUNDARY. A PASSING
SHORTWAVE FURTHER UPSTREAM TO OUR NORTH LATE WEDNESDAY WILL CAUSE
THIS FRONTAL BOUNDARY TO RETROGRADE TOWARD THE LARAMIE RANGE.
HOWEVER, SUNSHINE WILL KEEP DAYTIME HIGHS IN THE ABOVE AVERAGE
THRESHOLD FOR THE SHORT-TERM FORECAST PERIOD FOR OUR CWA. A PLEASANT
WEATHER REGIME WILL CONTINUE AS DAYTIME HIGHS IN THE 50S AND 60S
PERSIST EAST OF THE LARAMIE RANGE, AND SLIGHTLY COOLER TEMPERATURES
WILL HELP MELT SOME OF THE SNOWPACK FURTHER TO THE WEST ACROSS THE
MOUNTAIN ZONES.

BY LATE WEDNESDAY NIGHT, THE SHORTWAVE DISTURBANCE WILL TREK TO OUR
EAST, AND CAUSE THE SURFACE PRESSURE GRADIENTS TO TIGHTEN A BIT.
THIS WILL RESULT IN WINDS BEGINNING THEIR TREK UPWARD IN THE WIND
GUST POTENTIAL. WE ARE NOT LOOKING AT ANY HIGH WIND HEADLINES BEING
PRESENT, BUT IT MAY NEED ANOTHER LOOK ONCE WE APPROACH THE LATE
WEDNESDAY NIGHT AND EARLY THURSDAY TIME FRAME.
BETWEEN NOW AND THEN, ENJOY THE TRANQUIL WEATHER CONDITIONS.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 310 PM MDT Mon Mar 18 2024

The primary forecast concern in the long term forecast period will
be gusty to strong winds followed by the potential for a prolonged
period of rain and snow across southeast Wyoming and western
Nebraska through the weekend into early next week. Confidence
remains low in the impacts and precipitation totals due to the
strongest impacts being near a week out.

Southeast Wyoming and western Nebraska remain under the influence of
upper-level ridging Thursday through Saturday, keeping high
temperatures well-above-average in the afternoons. A brief surface
shortwave ejects southeastward through Wyoming and Nebraska Thursday
into Friday, briefly tightening the surface pressure gradients. This
increased pressure gradient may result in strong winds across
southeast Wyoming, mainly in wind-prone areas and at higher
elevations and ridgetops. Internal high wind guidance is showing
near 30% probabilities at Arlington and near 50% probabilities at
Bordeaux. Highest confidence currently is in wind gusts 40 to 50 mph
mainly Thursday afternoon.

Precipitation chances begin increasing Saturday as a trough moving
onto the west coast and a trough in western Canada flatten the ridge
over the central CONUS. As the first of a few frontal passages push
through, temperatures Sunday will drop back closer to normal, and
chances for rain in the plains increase. Sunday into Monday the
deterministic GFS shows the two troughs merging into one widespread
positively-tilted trough-y pattern across the whole western CONUS.
This cold front passage will drop temperatures much more
significantly and areas will begin to see a transition to a
rain/snow mix or all snow. The current NBM has mainly 30 to 50%
probabilities of at least 2 inches of snowfall in the High Plains
from Sunday to Tuesday morning. However, due to this pattern being
very messy and little model run consistency, many forecast elements
will change leading up to this weekend including temperatures,
winds, and precipitation totals.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1012 PM MDT Mon Mar 18 2024

Northwest flow aloft will continue. Clear skies will prevail.
Winds will gust to 22 knots at Rawlins from 16Z to 00Z.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.

&&

$$

SHORT TERM...BW
LONG TERM...LEG
AVIATION...RUBIN


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