Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Billings Montana
338 am MDT Tuesday Sep 23 2014

Short term...valid for today and Wednesday...

An upper low was sitting over northeast Wyoming early this
morning. Moisture was wrapping around this low and producing light
showers over southern Carter County. High resolution models linger
these showers this morning over far southeast Carter County and
then sweep them into the Dakotas by late morning. Brushed some
lower probability of precipitation back northwest this morning for this.

Otherwise...the rest of the area will be mainly dry as an upper
ridge tries to build in behind the upper low. The ridge gets
flattened a bit this afternoon as a shortwave...currently moving
into central Idaho...moves into western zones. This wave was not
that strong...but did produce convection over eastern Oregon and
eastern Washington Monday evening. Will keep some low probability of precipitation in the
west for this...but the wave should weaken as heights
kept the probability of precipitation out of central zones. 700mb temperatures around 8c
would lead to lower 80s today.

Tonight and Wednesday will dry out everywhere as heights rise
with a building ridge. Heights rise to 590dm over northern Wyoming
which is 2 to 3 Standard deviations above seasonal averages. An
impressive thermal ridge will develop underneath the amplified
ridge Wednesday and will lead to highs in the upper 80s. Record
highs are around 90 degrees for Wednesday...and the forecast is
within 3 degrees of that in Billings. Stronger mixing could make
it warmer will mention near record highs for Billings
on Wednesday. Thursday looks even warmer. Twh

Long term...valid for Thursday...Fri...Sat...sun...Mon...

Minimal changes to extended forecast period once again this
morning. Models appear to be in good agreement on overall
pattern...with amplified ridge giving way to cooler and wetter
conditions over the weekend and continuing into early next week.
However...the timing of the transition timing and positioning and
form of transitions across the region remains very
uncertain...with little model consistency in any form.

Dry conditions and near record highs for Thursday and Friday under
an amplified upper level ridge will see highs near 90 Thursday and
upper 80s for Friday. The pattern transition to cooler and wetter
weather over the weekend. The GFS continues to be the fastest
solution...with the European model (ecmwf) much slower. The amplified pattern
typically would suggest slower solution...which seems to be
somewhat support by GFS slowing over last several days. Suspect
that Saturday will be the transition day...with increasing
moisture into the region...and start of cool off. Sunday should be
cooler...and have better precipitation potential after atmosphere has
chance to moisten following such warm temperatures to end the
workweek. Cool and unsettled weather will continue into early next
week as broad troff remains in control over the region.
Temperatures will fall below normal for the early portions of the
work week...with highs around 60 for Monday and Tuesday. Aag



Scattered showers and isolated thunderstorms continue in
southeast Montana this morning...with MVFR flight conditions
possible in showers. Showers should clear to the east through the
morning. Otherwise...VFR conditions will prevail today under
mainly clear skies. There is a slight chance of isolated showers
and thunderstorms in area mountains this afternoon...resulting in
occasional obscurations. Aag


Preliminary point temp/pops...

Today Wednesday Thursday Friday Sat sun Monday
bil 083 057/087 058/091 058/087 055/066 048/064 046/060
1/u 00/u 00/u 01/u 23/T 34/T 33/T
lvm 082 050/087 051/088 051/085 048/066 046/062 041/063
1/north 10/north 00/u 11/b 34/T 55/T 53/T
hdn 084 054/089 056/091 055/088 052/070 048/067 046/064
1/u 00/u 00/u 01/u 12/T 34/T 33/T
mls 085 056/089 058/092 060/090 055/074 051/069 048/063
0/u 00/u 00/u 01/u 12/T 34/T 33/T
4bq 083 053/089 057/092 059/091 056/077 051/069 047/063
1/b 00/u 00/u 01/u 12/T 23/T 34/T
bhk 081 051/088 054/088 057/089 054/078 050/070 046/063
1/b 00/u 00/u 01/u 12/T 23/T 34/T
shr 081 049/087 051/089 052/089 052/073 049/066 045/062
1/b 00/u 00/u 01/u 12/T 34/T 33/T


Byz watches/warnings/advisories...



National Weather Service Glossary of Abbreviations