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Area forecast discussion...update 
National Weather Service Riverton Wyoming
1150 am MDT Monday Apr 27 2015

Short term...today through Wednesday night

Our weather system that dropped measurable rain or snow across much
of the state will be wrapping up over New Mexico and pulling away
much of the Richer moisture along with it...however its exit will
stretch a deformation axis over the state that will keep a few
showers around central and eastern portions of the forecast area
this morning. Most areas will be free of precipitation by the
afternoon but today will still be on the cool and moist side with
patchy morning fog expected in any areas with saturated ground or
snow cover. Tuesday and Wednesday will be rather nice with
temperatures rising back into the 60s to low 70s...light winds and
mostly clear skies.

Long term...Thursday through Monday

A weather system and cold front is still expected to pass through
the area Thursday into Thursday night. At this point the models have
the cold front laying out from NE Wyoming to SW Wyoming at 00z Friday. This
may aid in getting more showers or storms to form in the afternoon
and evening. For now will keep the higher chances in the mountains
and nearby foothills. On Friday the frontal boundary looks to be
over southern Wyoming. Drier air occurs over the north and central zones
with better moisture near the frontal boundary in the south. Thus
isolated showers/storms may occur in the south along the boundary.
Will leave very isolated activity in the mountains Friday PM and
evening. Saturday and Sunday look to have isolated to scattered
afternoon and evening showers/thunderstorms both days. The European model (ecmwf)
model is drier on Saturday than the GFS with both models similar on
Sunday. The GFS drops a cold front into northern Wyoming Sunday night and
it seems to stall out in central Wyoming Monday morning. With this
potential boundary for next Monday...afternoon showers and storms
could very well form along this boundary with more coverage in the
mountains. The European model (ecmwf) model seems to hint at this frontal push but
is certainly not as strong with the potential cooling. At this
point...not everyone will see showers and storms from Friday
through next Monday and certainly there will be many dry hours
each day. As for temperatures...still fairly warm Thursday ahead of the
front with cooler highs in the northwest and north as the front
gets there sooner. A little cooler Friday but the models have
backed off some on the cooling that it had last night for Friday.
Made slight adjustments at this point. Saturday through Monday
look seasonal with little variation from day to day on high temperatures.
Do I Dare call it "springtime" weather in Wyoming to start out may?

&&

Aviation.../12z issuance/

East of The Divide...kcod/kcpr/klnd/kriw/kwrl routes

The back edge of the main cloud deck along with the asct MVFR/IFR
conditions and mountain obscurations will gradually shift southeast
clearing kriw/klnd/kwrl by 20z this afternoon but will probably not
arrive in kcpr until around 00z this evening. The Casper terminal
will see a couple of hours of VFR conditions before a moist easterly
flow brings back low clouds or fog. Fog will also be possible across
much of the area tonight...especially in areas that received a good
amount of precipitation. After 15z Tuesday...expect VFR conditions.

Please see the aviation weather center for the latest information on
icing and turbulence forecasts.

West of The Divide...kbpi/kjac/kpna/krks routes

The back edge of the main cloud deck along with the asct MVFR/IFR
conditions and mountain obscurations will gradually shift southeast with
clearing expected at kbpi and kpna between 19 and 20z this afternoon
but will likely not arrive at krks until 23z. VFR conditions will
continue in kjac. Fog will also be possible across much of the area
tonight...especially in areas that received a good amount of
precipitation. After 15z Tuesday...expect VFR conditions.

Fire weather...

Our storm will clear out today however with high humidity and cooler
temperatures. Tuesday will be warmer and drier but with no wind
concerns. Wednesday and Thursday will be warmer as well but there
could be another...much weaker and quicker system grazing the area
which could increase winds to above 25mph on Thursday with some
humidities potentially into the middle teens across Rawlins and
portions of Casper dispatch during the day...latest models are even
bringing a dry cold front down during the day with a slight chance
for a thunderstorm with a wetting rain in the evening...but given
how much the details of this solution have changed over the past few
days...there could be some major changes before the day arrives.

&&

Riw watches/warnings/advisories...
none.
&&

$$

Short term...Allen
long term...Arkansas
aviation...wm/lipson
fire weather...Allen

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