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Area forecast discussion 
National Weather Service Billings Montana
951 am MDT Tuesday Oct 13 2015


Minor update to forecast this morning for the short term
forecast to raise daytime highs. Continued clear skies and west
winds gusting to 20 to 30 miles per hour are expected across the south
central Montana today. Downslope flow and good mixing potential
this afternoon will support warmer temperatures. Aag


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

Dry and mild weather will continue today and Wednesday thanks to
quiescent northwest flow aloft.

Today...a weak shortwave trough centered in far southern Manitoba
on early-morning water vapor imagery will push a weak surface cool
front across southeastern Montana early today. This will help enable a
mean westerly low-level flow across southern Montana and north central
Wyoming today...supporting highs in the lower to middle 70s f given mixing
to at least 750-mb per model-forecast sounding profiles. Winds are
again expected to be a bit gusty during peak heating and mixing...
with the highest gusts around 30 miles per hour near Livingston. Humidities
will fall to between 15 and 20 percent...yielding a couple-hour
period of elevated fire danger in fine fuels once again today.

Tonight...lows will be in the 40s...with upper 30s f likely in the
lower-lying areas of southeastern Montana like Baker.

Wednesday...forecast soundings suggest the depth of the well-mixed
layer may not be as high as today...and the 00 UTC NAM...GFS...and
European model (ecmwf) all support a shift to lighter northerly flow in many places
by late afternoon as a weak backdoor cool front approaches. Highs
may therefore not be quite as warm as today...but should still be
near 70 f in many areas. That is based on the warmer edge of the
00 UTC guidance that we generally leaned on for daytime highs and
humidity values for both today and Wednesday given a dry and well-
mixed boundary layer and recently-observed model biases. Schultz

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

Current extended forecast looks on track and therefore did not
make large changes. Two interesting periods of weather from
Thursday through next Monday...and that would be early and then
again late. Shortwave energy drops into North Dakota early
Thursday. This backs a cold front into the region for a
cooler...albeit seasonal...Thursday. Friday will be a little
warmer as heights build but limited mixing will keep highs just
above seasonal averages. The bigger warm up will be Saturday and
Sunday as ridging slides over the area and flattens out.

The Sunday and Monday period is where models diverge a bit. Both
develop a split flow to the pattern...and both increase precipitable water
values to around three quarters of an inch. The norther part of
the split flow will send energy across Sunday and Monday with the
GFS much more aggressive on energy and quantitative precipitation forecast generated. Both the GFS
and European model (ecmwf) were advertising a more unsettled pattern with cooler went along with probability of precipitation during this time frame with
highs falling back to seasonal averages. The system does not look
cold at all with the cold air locked up in Canada. Twh


VFR conditions on tap through the period. Winds will turn
westerly this afternoon as mixing brings westerly winds to the
surface. Kbil and klvm could see 25knot gusts early this afternoon
before a weak front lessens winds to 5 to 10 knots later this
afternoon. Dobbs


Preliminary point temp/pops...

Today Wednesday Thursday Friday Sat sun Monday
bil 077 045/071 043/060 035/062 039/069 046/074 048/064
0/u 00/b 01/b 00/u 00/u 00/b 32/west
lvm 078 043/075 037/061 033/067 038/074 045/069 043/061
0/north 00/north 00/u 00/u 00/u 01/b 33/west
hdn 077 042/072 041/061 035/064 039/071 043/076 045/066
0/u 00/b 00/b 00/u 00/u 00/b 22/west
mls 074 043/070 040/058 032/061 038/067 043/072 045/065
0/u 00/b 00/b 00/u 00/u 00/u 12/west
4bq 074 042/071 041/058 033/063 038/069 045/074 046/064
0/u 00/b 00/b 00/u 00/u 00/b 12/west
bhk 070 039/067 038/055 030/056 036/062 041/072 044/063
0/u 00/b 00/u 00/b 00/u 00/u 12/west
shr 076 041/073 040/059 033/066 038/072 042/074 042/061
0/u 00/u 00/b 00/u 00/u 00/b 23/west


Byz watches/warnings/advisories...



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