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Area forecast discussion 
National Weather Service Riverton Wyoming
411 PM MDT Monday Apr 27 2015

Short term...tonight through Tuesday

The low center that was responsible for the significant precipitation
across the area over the County Warning Area over the weekend has now propagated
all the way to the Oklahoma Texas border. The outer cloud band of
the thickest cloud deck extending out from the low center seems
to have moved as far southeast as Casper where they are holding tough
with an overcast deck of 1700 feet. North and west of there and
underneath the slowly exiting thinner high and middle cloud
decks...lower stratus and stratocu/cumulus decks are slowly
breaking apart with the lower broken deck at around 3k situated across
Sweetwater County...Upper Green river basin...Wind River basin and
northeast to Johnson County. The far west and Big Horn basin are
in the clear. Casper will be the last to clear out just before
sunset. Clouds should clear off enough for patchy fog to form
tonight in areas that had abundant moisture over the weekend albeit
not the best sounding profile for fog to form so we are looking at
shallow patchy fog that should dissipate by 15z Tuesday.

Otherwise expect sunny and pleasantly warm temperatures for
Tuesday as a positively tilted ridge builds in from the west.

Long term...Tuesday night through Monday

Ridge holding over the area through Wednesday with Wednesday being
the warmest day for most areas. Later Wednesday night into Thursday
our weak shortwave moves east across the northern sections with a weak
frontal boundary sagging south into central Wyo during the day
providing some focus for afternoon convection. Added in isolated
showers and thunderstorms along the Cody foothills south to the western half
of the Wind River basin and adjacent mountains. Nothing special but
modified soundings indicate some potential for 100-200 j/kg with the
front/terrain providing some focus. Modest middle level westerlies may
aid in a little shear also. These showers/isolated storms may drift
into the eastern zones during the evening. Tail end of this weak wave
may help with some far southern storms on Friday. One other item with
this shortwave Wednesday night/Thursday is some modest mountain wave signature with
increasing winds along the Cody foothills Wednesday night ahead of
the front. Could be quite windy for a few hours in the foothills
before the front shuts off the wind. Not seeing high wind right now
but enough to add in some windy conds. Another disturbance in the
far north will be close to aid in isolated mainly mountain showers/storms.
On Saturday...heights start to build and a little additional
moisture may try to edge up from the south. Still in doubt on how
much moisture may or may not be lifted northward but will keep in our
isolated in the south half. Moisture from the northern stream will be close
to the northern mountains a little stronger shortwave Sunday will push a
cold front south up against The Divide while additional moisture is
expected to lift NE aiding in a better chance of showers and
thunderstorms for most of the area... especially along and east of
The Divide. Additional moisture may lift NE while the boundary
remains as a potential upper low moves into California Monday. Bottom
line...an increasing chance of showers and thunderstorms Sunday into
Monday.

&&

Aviation.../00z issuance/

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

The back edge of the solid main cloud deck along with the asct
MVFR conditions with ceilings around 2k and mountain
obscurations...directly associated with the exiting low pressure
center now situated along the Texas Oklahoma border...will
continue to gradually shift southeast reaching kcpr by 03z this
evening. Kcpr will then experience gradual clearing for the rest
of this evening with improving ceilings. North and west of the back edge
of the aforementioned multilayered cloud deck...a lingering broken
deck of lower clouds will mostly dissipate by 01z where ceilings are
averaging around 3k. The far west and Big Horn basin are already
experiencing VFR conditions. By 06z most areas will experience VFR
conditions with some lingering patchy cloud decks at around 5 or
6k or so. Shallow patchy fog is expected over many areas tonight
through 15z Tuesday. Otherwise VFR conditions are expected
Tuesday.

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

&&

Fire weather...

Our clouds will continue to clear out this evening...however with
high humidity and shallow patchy fog over many areas tonight and
Tuesday morning. 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 25 miles per hour 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 in the forecast before
the day arrives.

&&

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

$$

Short term...lipson
long term...skrbac
aviation...lipson
fire weather...lipson

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