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Area forecast discussion 
National Weather Service Goodland Kansas
1000 am MST Sat Feb 28 2015

Update...
issued at 511 am MST Sat Feb 28 2015

Persistent light snow this morning over central and eastern zones
has prompted an early increase in probability of precipitation to these areas. Is showing
up more steadily a bit earlier than expected. Have adjusted
snowfall potential slightly to accommodate these changes...but
otherwise forecast still in good shape.

&&

Short term...(today and tonight)
issued at 220 am MST Sat Feb 28 2015

Cold conditions across the tri state region this morning as
temperatures range in the low teens and single numbers under
mainly cloudy skies. Surface high pressure is set up to our east
with low pressure off into The Rockies. This setup is giving the
area a southerly gradient...which is giving the area wind chill
reading in the single numbers above/below zero. Light scattered
snow showers are also falling across the area this morning as an
upper level shortwave lifts out of the desert SW towards the
Central Plains region. Most of the dynamics with this system will
pass to our south during the day...with models only carrying a
weak 700mb trough across the area...followed by weak middle level
ridging going into the evening hours. For today though...as system
passes the area...high temperatures in the 20s will afford the County Warning Area a
chance for -SW...with best chance for any light accumulate to be over
S/southeast zones...which will be closer to main trough dynamics as it
passes. For the evening/overnight hours brief break early on as
ridge passes over area ahead of next shortwave system and
associated surface frontal boundary. For tonight though...keeping
chance probability of precipitation in for light snow with only a few tenths of an inch
accumulate. Best chances will occur over northern and western zones due
to approach of next system towards morning.

Long term...(sunday through friday)
issued at 220 am MST Sat Feb 28 2015

Going into Sunday and on into Monday night. Surface ridge will
move out of the northern rockies and out east into the Central
Plains region during the arrival of next shortwave/front for
Sunday/Sunday night. Southerly gradient setting up between the two
systems will put main precipitation focus over western area. Surface
ridge will give way to a bit more potent shortwave that works out
across The Rockies and through the tri state region before exiting
east into the plains by Monday night. Model track with this
system will be key to amount of quantitative precipitation forecast potential and thus light snow
fall. A track over the area will keep low chances for the
County Warning Area...but a track more to the south will bring more quantitative precipitation forecast into area
on wrap-around circulation potential. With model differences
showing up...will keep chance probability of precipitation in for now at best for northern
zones based on expected track. Slight increase in expected temperatures
over the two-day period with highs in the 30s to near 40f and
lows in the teens Monday...to 20s Tuesday. Lack of cold air advection working
into area based on ridge movement before arrival of final
shortwave Monday night aids in this scenario.

Tuesday-Wednesday night...longwave trough will continue to be the
dominate feature across the plains during these periods...with
active west-SW flow in place over our County Warning Area. Shortwave trough moves out
of the central/southern rockies into the plains Tuesday with another
Arctic front dropping south over the County Warning Area during the day. While flow
aloft would generally indicate subsidence there appears to be enough
middle level forcing along with frontogenetic forcing immediately
behind this cold front to support at least light precipitation chances
Tuesday through Wednesday morning. Better precipitation signal seems to be
Tuesday night especially in the west. Temperatures will be tricky as a
result of the frontal passage...with southern County Warning Area possibly a little warmer if
front passage is in afternoon instead of morning/midday Tuesday.
Breezy to windy conditions will also develop over the County Warning Area as this
front moves through the region...and I could see a few locations
gusting around 45 miles per hour or higher through Tuesday afternoon based on
GFS/European model (ecmwf) winds aloft. Will mainly be depended on mixing and timing
of peak pressure rises. Other concern in these periods will be
potential for advisory criteria wind chills Wednesday morning and again
late Wednesday night/early Thursday morning. Arctic air should be in place
so question will be nighttime winds and impacts of cloud cover on
radiational conditions. Worth keeping mention in severe weather potential statement...but still
pretty far out.

Thursday-Friday...as has been the case guidance continues to show a
significant pattern change by late next week. Large scale ridge
should begin to develop across the eastern US and build east into the
central rockies/Western Plains. Result will be a much more
stable/dry pattern and moderation in temperatures aloft across the County Warning Area.
While we could still have complications from snow pack over parts of
the County Warning Area...considering the significant shift in pattern and warming
temperatures aloft we should see temperatures around or above seasonal normals by
Friday (if not earlier). I stuck with consensus...but could actually
see our County Warning Area 3-5f warmer both Thursday and Friday with good mixing
than current forecast.

&&

Aviation...(for the 18z tafs through 18z Sunday afternoon)
issued at 1000 am MST Sat Feb 28 2015

Kgld...MVFR/IFR ceilings and visible in light snow expected from taf
issuance through roughly 23z with winds from the south around
11kts. By 00z terminal should be in between weather systems with
southeast winds under 10kts and ceilings improving to VFR. Next
system moves in from the southwest after 03z bringing another
chance of light snow with MVFR/IFR ceilings and visible through 08z. As
low level moisture lifts northeast ceilings may improve to VFR in the
08z-14z timeframe. After 15z drier air tries to work north of the
terminal and should generally see VFR conditions but MVFR ceilings
wont be far away. Winds from the northwest under 10kts.

Kmck...MVFR ceilings expected through 20z with winds from the south
around 10kts. Low level moisture decreases a bit and should
provide a rise in ceilings just above MVFR range from 21z through 07z.
Weather system moves in from the southwest bringing an expected
return to MVFR ceilings with some snow showers or light snow in the
vicinity. If one of these should move directly over the terminal
visible likely to drop to MVFR range as well through 16z. After 16z
MVFR ceilings expected with no precipitation and north winds just over
5kts.

&&

Gld watches/warnings/advisories...
Kansas...none.
Colorado...none.
NE...none.
&&

$$

Update...jn
short term...jn
long term...jn/Dr
aviation...99

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