Area forecast discussion
National Weather Service Riverton Wyoming
230 PM MDT sun may 19 2013
Short term...tonight through Wednesday
moist...complex upper low with multiple circulation centers will
impact the region through at least Monday and the far eastern zones
even into Tuesday as the lows try to gradually consolidate over
the northern High Plains. The moist north to NE flow and general ascent on
the west side of the circulation centers will keep the showers
going across much of the area through Monday. Precipitation
amounts of another one half to one inch are quite possible with
up to 2 inches in the mountains and foothills. Some areas are
already quite soggy from the April and recent rains so we'll just
have to watch those areas closely. Don't feel the need for flash
flood watches as rains are not associated with heavy thunderstorms
but just enhanced areas of showers and enhanced stratus bands.
Concentrated areas could need urban or small stream flood
advisories though later today or tonight and even into Monday.
Snow levels have been as low as 6500 feet but generally above 7500
to 8000 feet. Gradual improvement most areas Monday night and
Tuesday with the far northestern zones lingering a chance of showers the
longest. The next shortwave on Wednesday could produce strong
thunderstorms in the northwest half as front boundary produces a moist southeast
flow in the east half and shortwave provides the dynamics for the
central and northwest sections along with warmer temperatures to allow
for more instability.
Long term...Wednesday night through Sunday
large pacnw storm system will be the main weather feature during
the medium range period as multiple shortwaves in the southwest
flow ripple NE across the area leaving the County warning forecast area vulnerable to
showers and thunderstorms even as it retreats into southern Canada over
the weekend. Little changes to the going forecast with active
short term rain event. Wednesday's storms could be quite active
where moist southeast flow interacts with northeastward moving
shortwave...especially northwest half. Front is expected to lift NE on
Thursday but embedded disturbances will potentially act on moist
ground to create instability and more storms in and near the
mountains especially. The drier air will try to filter in Friday
but position of trough and embedded potential disturbances may
produce more convection than the models are currently indicating.
Little change over the weekend.
Aviation.../00z issuance/
A weather system will continue to impact the region through 12z
Monday. Widespread areas of rain and High Mountain snow will occur
over the region east of The Divide through 12z Monday. West of The
Divide rain and mountain snow will occur in northwest Wyoming. Scattered rain
showers will be common in southwest and southern Wyoming through 12z
Monday. VFR to MVFR conditions will occur in southern and southwest
Wyoming while MVFR to IFR conditions along with mountain obscurations
will prevail over the rest of the region.
Fire weather...
A cool and wet storm system will continue to impact the area
through Monday before improving conditions return on Tuesday. Most
areas will see off and on rain with higher elevation snow through
Monday along with periods of gusty north to northwest wind.
Another storm system will bring a chance of thunderstorms to the
northwest on Wednesday with gusty south to southeast winds across
the area.
&&
Riw watches/warnings/advisories...none.
&&
$$
Short term...skrbac
long term...skrbac
aviation...lipson
fire weather...skrbac
