Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Billings Montana
352 PM MDT Monday Mar 10 2014
Short term...valid for Tuesday and Wednesday...
Minor updates to the forecast this afternoon as the wet Spring
storm system remains on track. The strong Pacific wave can be seen
on WV imagery tracking into eastern Oregon this afternoon with
strong synoptic lift developing across the entire forecast area.
Rain has been the predominate precipitation type today...but the
snow level is slowly lowering as locations in higher elevations
like Judith Gap...McLeod...and Big Timber are already switching
over to snow. The transition to snow will continue from the
northwest to the southeast tonight as cooler air moves into the
forecast area and continued dynamic cooling aids in the
Models have trended toward a slightly early transition across the
area...with an expected transition around 03z in Billings. The
transition will be earlier to the north and west...and later to
the south and east. Models remain steadfast in with the quantitative precipitation forecast
consensus and still project a widespread half inch to an inch.
Thus...given the increasing confidence in the earlier
transition...have slightly increased snow amounts overnight.
Models also continue to track the 700 mb low just south of the
forecast area...switching the 700 mb winds around to the northeast
after 00z. With this switch in 700 mb wind direction...the
increasing qg forcing and 700 mb frontogenesis...much of the area
will see precipitation develop and increase overnight. The higher
precipitation rates will also aid in snow accumulation since
temperatures will only be hovering near freezing. The foothills
locations will see very heavy snowfall overnight with the deep and
unstable upslope flow.
Blowing snow will become a concern for Sheridan County Wyoming and
far southeast Montana as the surface low deepens and winds
increase after midnight. Winds will increase to around 20 miles per hour with
gusts to around 30 miles per hour...thus visibilities will be reduced due to
blowing snow and may cause some areas of drifting.
Dryer air will work into the area from the north Tuesday
morning...and precipitaton will end quickly from north to south
by noon on Tuesday. Would not be surprised to see the sun start to
break through the clouds by Tuesday afternoon...especially across
the northern portion of the County Warning Area. Temperatures will rebound into
the upper 30s and low 40s on Tuesday...and thus the snow will
begin to melt quickly. Given the high liquid water content of this
snow...the runoff could contribute to the flooding problems in
places that have seen problems over the past week.
Long term...valid for Thursday...Fri...Sat...sun...Mon...
New extended solutions had the same basic ideas shown by the
previous model runs...but had some differences in shortwave
timing. Northwest flow with waves moving through the flow will be over
the region Thursday through Monday. A dry shortwave passage was still
forecast for Thursday. The GFS brought the next wave in for Friday night
while the European model (ecmwf) brought the wave in for Sat. The GFS did bring
some moisture in ahead of the wave on Friday while the ecwmf was dry.
Will need to watch trends for Friday in future model runs to see if
models come into better agreement. Probability of precipitation for Friday night and Sat
looked reasonable. Sun continued to look dry under upper
ridging...then model disagreement emerged again for Monday. Again
will need to watch model trends before making adjustments to the
uncertain periods. Cold air was still forecast to remain north of the
area through the period. Arthur
Rain will continue to overspread the area this afternoon and mix
with snow. Conditions will range from MVFR to LIFR. Expect the
precipitation to change to all snow between 00z and 06z across the
whole area with IFR to vlifr conditions. Snow will continue over
most of the area overnight. The NE big horns will become obscured
late this afternoon and remain obscured tonight. The
beartooths...absarokas and crazys will be obscured through
tonight. The precipitation will taper off from north to S through the
day on Tuesday resulting in improving conditions. Areas of mountain
obscuration Tuesday morning will become localized Tuesday afternoon.
Preliminary point temp/pops...
Tuesday Wednesday Thursday Friday Sat sun Monday
bil 028/040 028/051 032/054 032/052 037/051 035/055 036/052
+2/o 10/u 00/u 00/b 23/west 10/u 22/west
lvm 022/039 023/048 029/051 029/051 032/048 028/051 033/052
+3/o 10/u 01/north 00/b 23/west 10/u 22/west
hdn 027/042 028/051 031/056 035/055 038/052 034/057 037/054
92/o 10/u 00/u 00/b 23/west 20/u 22/west
mls 027/044 031/052 032/057 033/051 034/050 032/057 038/052
91/north 10/u 01/u 00/b 23/west 20/u 22/west
4bq 028/041 030/052 031/057 035/052 036/050 034/054 037/054
+2/o 10/u 00/u 00/b 23/west 10/u 23/west
bhk 024/043 027/051 030/056 029/048 029/047 029/053 034/051
81/north 10/b 00/u 00/b 23/west 20/u 23/west
shr 029/037 022/049 026/055 027/053 030/049 027/055 030/053
+3/o 10/u 00/u 00/b 23/west 10/u 22/west
Montana...Winter Weather Advisory in effect until noon MDT Tuesday for
Winter Storm Warning in effect until noon MDT Tuesday for
Wyoming...Winter Weather Advisory in effect until noon MDT Tuesday for