Area Forecast Discussion
Issued by NWS Cheyenne, WY

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679
FXUS65 KCYS 282049
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
249 PM MDT SAT MAY 28 2016

.SHORT TERM...(This evening through Monday Night)
Issued at 249 PM MDT Sat May 28 2016

Some showers and storms moving east across mainly the northern
parts of the CWA this afternoon but low shear and modest
instability keeping them fairly benign. Expect this activity to
diminish this evening as the boundary layer cools and instability
falls off.

No major changes in the overall weather pattern seen across the
area through Monday with a weak upper low over moving slowly east
over the desert SW and a stronger upper low that should move to
the Montana/southern Canadian border on Monday. Weak impulses
will move across the CWA in a generally westerly upper flow and
combine with instability to produce scattered mainly afternoon and
evening convection. Somewhat better shear and instability expected
across the northern parts of the CWA Monday as the upper low moves
a little closer so some stronger storms a better bet on that day
in that area. Otherwise temperatures seasonal over the next couple
days.

.LONG TERM...(Tuesday through Friday Night)
Issued at 249 PM MDT Sat May 28 2016

Models remain in agreement with swinging an upper level trough
across the high plains on Tuesday and Tuesday night, while surface
high pressure builds in from the west. The attendant cold front
is expected to be through our forecast area to the south by
Tuesday morning, so forcing for any ascent will be focused along
the Laramie Range and higher mountain peaks in upslope flow, and
where best instability will occur with cooler air aloft. High
pressure at the surface and a building ridge overhead will limit
convection for Wednesday although there remains a low chance for a
weak shower/storm over the higher peaks. Similar conditions will
persist for Thursday and Friday, while temps warm with the upper
ridge moving overhead. Could begin to see an increase in snowmelt
at this time, thus will have to monitor rivers closely for
potential rises.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1206 PM MDT Sat May 28 2016

Convection is becoming more widespread on satellite and radar
imagery late this morning. Expect vcts and -tsra to affect most
terminals through early this evening, especially as a cold front
drops south across the plains early this evening. Should see mvfr
vsbys in the heavier storms. Convection will diminish after sunset
with light winds prevailing through the night. Winds will shift to
the east-southeast and boundary layer moisture will increase
behind the front as well. So a return of fog is possible for most
lower elevation sites in the Nebraska Panhandle. Southerly winds
in the Laramie Valley could also promote fog formation at KLAR as
well late tonight, but confidence is somewhat low at this point.

&&

.FIRE WEATHER...
Issued at 249 PM MDT Sat May 28 2016

Fire weather concerns to remain low into the early part of next
week with non-critical conditions continuing. There will be
widely scattered mainly afternoon and evening showers and
thunderstorms into early next week with wetting rains from some of
these.

&&

.HYDROLOGY...
Issued at 249 PM MDT Sat May 28 2016

The North Platte and Laramie Rivers continue to run high but
should remain steady or continue to slowly decline over the next
couple of days with relatively steady reservoir releases and with a
cool environment in place. Warmer temperatures next week will
begin to increase snow melt again...so rivers will be on the rise.

&&

.CYS Watches/Warnings/Advisories...
WY...None.
NE...None.
&&

$$

SHORT TERM...RE
LONG TERM...RJM
AVIATION...RJM
FIRE WEATHER...RE
HYDROLOGY...RJM



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