Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gaylord Michigan
353 PM EDT sun Mar 9 2014
issued at 352 PM EDT sun Mar 9 2014
High pressure will settle to our south...allowing milder air to push
back into the Great Lakes region from the southwest through Monday.
A series of systems will pass to the north and south of the region
during the first half of the week...bringing only very small chances
for precipitation. Much colder air will return to the region Tuesday
night into Thursday...behind a departing strong clipper.
Short term...(this evening through tonight)
issued at 352 PM EDT sun Mar 9 2014
Low amplitude northwest flow aloft from south-central Canada into New
England. Entrance region of 120 knot upper jet stream driving into
the northern lakes region this afternoon with an associated middle level
vorticity center and associated main area of forcing moving
through Ontario. Meanwhile...a somewhat tight lower level thermal
gradient is pushing through the western Great Lakes currently...0c
800 mb line working through the County Warning Area per guidance forecasts. This pulse
of warm advection forcing has/is producing a pocket of light
precipitation across the northern part of the County Warning Area...largely elevated (virga)
although some light snow has been falling in eastern Upper
Michigan particularly the Soo where 0.3 inch was reported there at
2 PM. Drier low level air further south has thus far prevented any
Tonight...warm advection forcing will push off to the east quickly
this evening...ending the light precipitation threat. That/S the easier
part. But what happens next is more uncertain. Guidance forecast
soundings and low level relative humidity forecasts continue to suggest the
development of low clouds/stratus via a near surface based saturated
layer to around 3k feet. No sign of that immediately upstream. But
increasing low level dewpoints from the west over the snow pack...
coupled with nighttime boundary layer cooling certainly supports
that idea. Going forecast has that idea and have no compelling
reason to change it at this point...and thus will maintain overall
cloudy skies through the night. However...given the uncertainty
and that depicted low level saturated layer is not that deep to
begin with...have removed light nuisance precipitation from the forecast.
Is possible for spotty very light fzdz at times over the higher
terrain...but Don/T think it/S Worth noting in the forecast.
Long term...(monday through sunday)
issued at 352 PM EDT sun Mar 9 2014
..relatively quiet period of weather west/alternating cold/mild
shots...with an overall trend to below normal temperatures...
High impact weather potential: minimal
Large scale indices continue to support now multiple Middle Range
deterministic/ensemble package runs that an overall rather quiet
period of weather is expected through the course of the upcoming
week. Loss of cross-polar flow/more Pacific influences to bring much
more typical up/down temperature swings...although with background
ridge west/trough east configuration...overall temperature flavor
continues to be below normal...with definitely no signs of any
prolonged warm-up anytime soon.
Primary forecast concerns/challenges: addressing rather significant
temperature trends and periodic light precipitation potential.
Those looking for some rather respectable early Spring warmth have
to look no further than Monday...with at least northern lower
Michigan squarely within warm sector of passing Ontario clipper.
Low level thermal forecasts spike...with 800 mb temperatures reaching low
and middle single digits above zero south of the bridge. Just how mild
things get centers on cloud and light precipitation trends.
Addressing both remains a rather low confidence Endeavor. Moisture
looks to remain disjointed at best...with more coherent deep layer
moisture remaining off to our north closer to clipper system.
NAM-WRF remains insistent on sub 9h saturated conditions...and as
mentioned by overnight forecaster...is a well known biases with that
piece of guidance. Might see some sprinkles/flurries across parts of
eastern upper...but feel any measurable precipitation should remain
across Lake Superior into Ontario. Giving what appears to be (for
now) overly aggressive low level moisture forecasts across northern
lower Michigan...think at least some filtered sunshine will be
realized. More persistent clouds expected across eastern Upper
Michigan. This brings US back to temperatures...and with anticipated
warming low level airmass...decent mechanical mixing via southwest
winds...and some sunshine...still kinda like the warmer end of the
guidance numbers showing highs well into the 40s over northern lower
Michigan. More clouds/slightly cooler airmass looks to keep eastern
upper just a touch cooler...but still pushing above normal values.
Interestingly...00/12z regional Gem bias corrected numbers...which
did exceptionally well with past friday's burst of mild air...has
most of northern lower pushing 50 to the lower 50s...and downslope
areas of northeast lower making a run into the middle...and even
upper...50s (oh boy!). does make one wonder if monday's forecast
highs might be a touch conservative. Sure no one would mind if that
was the case :).
Other than temperatures...simply not too much to talk about right
through next weekend. Still appears a decent late season winter
storm may impact parts of the southern lakes/Ohio Valley later
Tuesday into Wednesday...with upper air/seasonal trends supporting
the northern edge of the steadiest snowfall remaining just to our
south. Nice fgen streak of forcing noted in most forecasts bringing
initial round of snowfall before main system development across
Southern Lower Michigan. Will introduce at least some possibility
for light snows later Tuesday into Tuesday night along/south
of M-55. Flow afterwords remains supportive of additional clipper
systems... although timing and impact anything but certain. Model
consensus blend approach introduces some low end snow chances across
the north to end the work week into the weekend...and really can't
argue with such. Bigger news through this period will be roller
coaster temperatures...with quick shot of cold air dropping highs
Wednesday back into the teens and 20s. Really like idea set forth by
midnight crew of sub zero readings once again Wednesday night with
high pressure/clear skies setting up ideal radiational cooling
conditions. Readings hopefully rebound some heading through the end
of the work week...with some evidence another surge of colder air
will visit the region over the weekend.
Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 103 PM EDT sun Mar 9 2014
Solid VFR conditions through this afternoon with broken-overcast middle cloud
cover...but surface winds a bit gusty from the SW (gusts up around 25
knots developing). Low confidence ceiling forecast for tonight through
Monday morning however. Shorter range guidance sources continue to
support the development of low cloud cover across northern Wisconsin
and ultimately across northern lower Michigan through the evening
hours...with ceilings turning MVFR...apparently in response to
warmer/more moist air advancing over a cold boundary layer and
aided by nighttime cooling cycle. And...some hints of low clouds
even now just north of the Minnesota arrowhead now...where
guidance suggests it should be. So...have some confidence that
saturating low levels and stratus will develop...but we will just
have to see. Inherited aviation forecasts have MVFR ceilings
developing tonight and persisting into Monday morning and simply
have no compelling reason to change that.