Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gaylord Michigan
641 am EDT Sat Oct 25 2014
issued at 347 am EDT Sat Oct 25 2014
A cold front working through the region will deliver a brief round
of clouds this morning...but with breezy conditions and clear skies
for the afternoon and into tonight as somewhat cooler air slides
into the area. Winds will slowly diminish on Sunday as high pressure
inches closer...but with temperatures back on the cooler side.
Developing low pressure over the upper Midwest will lift a warm
front into Michigan for Monday...followed by a cold front
Tuesday...with these features providing a few rounds of showers and
thunderstorms. Breezy and much cooler conditions will make a return
into midweek...along with chances for some lake effect rain showers.
Short term...(today through tonight)
issued at 347 am EDT Sat Oct 25 2014
..clearing with gusty winds developing...
Current weather and synoptic pattern:
Low pressure in Ontario is deepening with the emergence of a
strengthening 100+ knots upper level jet punching into far northern Minnesota. A
warm front was stretched southward from this low pressure and was
working toward northern Michigan. The atmosphere was fairly dry...and
working with minimal moisture...but core of stronger forcing/-divq
over the sault/far Eastern Lake Superior was allowing for some radar
returns. This will likely bring at least some sprinkles across these
areas over the next few hours. Otherwise...the main feature of note
is the upstream cold front which was racing through western Upper
Michigan and northwest Wisconsin. Low clouds were clearing out ahead of
this front...presumably due to stronger winds/mixing and warming
into the stratus that was there earlier. Winds were gusting pretty
well back behind the front with clear skies being the rule.
Across northern Michigan...we still have the stratus hanging around most
all areas...with VAD wind profiles showing not as strong bl winds
and with low level moisture increasing with the warm front. The
stratus was lowering out across eastern Wisconsin...but any reports
of drizzle have been few and far between...and with the clearing
seen ahead of the cold front...drizzle chances are seemingly
dwindling. The best shot for a brief 2 hour window of possible drizzle
looks to be only in the higher terrain of interior northern lower.
Temperatures were fairly steady or slowly rising..in the middle 40s
and lower 50s.
Synoptic pattern/weather evolution:
Am expecting the lower clouds to hang around through daybreak
across northern lower...but the rapid advancement of clearing across
Upper Michigan suggest that eastern upper may southeast some of this
clearing right at daybreak or sooner. The cold front will continue
to race into northern Michigan this morning...and exit by middle day.
So...outside of the shot at drizzle in the higher terrain of
interior northern lower early this morning...drying behind the front and
stronger winds/stronger mixing in slight cold air advection...will quickly bring
more sun than clouds through the morning. A tightening pressure
gradient and deeper mixing will result in more lowered dew points
than MOS in the afternoon...and pretty gusty winds coming out of the
west-northwest...also lower than guidance suggests. Winds will be gusting as
high as 30 miles per hour by midday and into the afternoon. The gusty winds
will surely continue into this evening...and to some degree
overnight. Also...a shortwave drops down the backside of the upper
low...which tracks into Quebec tonight...dragging down some better
moisture from the north. This will likely allow for some mostly
cloudy skies to scrape through portions of eastern upper tonight.
Not sold on skies becoming that cloudy in northern lower just yet...but
signals are there showing some bl moisture and a developing
Highs today may be sneaky mild...with clearing skies immediately
behind the front and deep mixing (although we should be seeing some
cooling aloft mixing to the sfc)...highs could quickly bounce into
the upper 50s...with lower half of the 60s in downsloping regimes of
NE lower. Lows tonight dropping into the upper 30s and around 40f
due to some gusty winds/slightly mixed bl.
Long term...(sunday through friday)
issued at 347 am EDT Sat Oct 25 2014
..an active sendoff to October...
High impact weather potential: possible thunderstorms Monday evening
through Tuesday...with a low end threat for some stronger storms
depending on the timing of a cold front. Potentially windy into
midweek pending the strength of low pressure to our north...with
much colder conditions toward Halloween or just after.
Pattern summary/evolution: let's just come right out and say it -
confidence is not exactly stellar heading into middle and late week
with regard to the strength/position of low pressure to our
north...which will ultimately dictate just how much wind and/or cold
can get down this way toward Halloween. However...the overall gist
is for broad upper ridging to briefly arrive on Sunday...ahead of
sharper troughing digging through the northern rockies. That upper
trough will eventually take a swing at our region through the first
part of the work week...lifting a warm front into the area on
Monday...followed by a cold front sometime on Tuesday (timing of
that is still in question). Broader upper troughing is expected to
persist into middle and late week with a couple reinforcing shortwaves
meandering through the flow...with one or two of those potentially
carving out an even deeper shortwave trough sometime toward Friday
or next Saturday.
Let's sort out the details:
Sunday-monday: simply put...a period of change! Continue to see
significant hints of shallow sub-900mb cooler air oozing in through
the first half of the day on Sunday...with h9 temperatures dipping into the
0c to 3c range suggestive of some potential for pesky lake-induced
stratocu to fill the skies in mean northwesterly flow areas...and
perhaps even farther inland beneath said cooler air. That would of
course be par for the course up here in northern Michigan (our
official regional cloud is the stratocu after all)...and based on
the setup...feel a bit more of a pessimistic cloud trend is the way
to go...along with cooler highs perhaps stuck in the upper 40s
higher terrain and over the eastern u.P.
Things begin to change Sunday night as we lift an elevated warm
front through the area...with a nice surge of enhanced moisture
(pwats 1+") working through southwest portions of the County Warning Area late.
Trends the past 24 hours support a slightly slower onset of better
rain chances...helped along by ambient quite dry air intact over the
area for much of Sunday night. However...should see at least some
showers knocking on the door late...but slower looks better at this
point. With that said...given the later expected arrival...and some
room for clearing as low level ridging works across the area...would
not be shocked to see many areas take a dive in the temperature
department through the first half of the night...perhaps making a
run back below freezing in spots.
Quite the nice surge of deeper layer moisture advection coupled with
a shot of ascent just north of the actual surface warm front should
drive a band of showers through pretty much the entire County Warning Area into
Monday afternoon...with enough confidence to at least raise probability of precipitation to
the likely range based on the setup. Wouldn't be totally shocked to
see even a touch of thunder on the southern fringe of the rain
shield as the middle levels dry out and showalter indices take a dive
to around -2 to -3c...indicative of an axis of quite steep 700-450mb
lapse rates working north through the region.
Monday night-wednesday: what GOES up must sadly come down...and that
will be especially true with temperatures into midweek. Should see a
nice spike in temperatures Monday night as the warm front is forced north...
with another round (or two) of rain arriving with the approach of
the upper trough and associated cold front. Thunder chances will
also continue...and continue to see some signs of possible stronger
storms given the amount of shear aloft. However...as is quite often
the case this far north...it appears that the best instability may
outrun the strongest shear down into southern Michigan or the Ohio
Valley...with an earlier cold front passage up this way really
limiting any severe threat. Still something to watch though. In
addition...won't be totally shocked to see rain chances quickly
dwindle for many areas by middle morning as strong middle level dry
slotting arrives...particularly if a more wrapped up solution comes
to fruition. Should be a warm start the day on Tuesday...with some
eastern spots well into the 60s if we can hold up the front just
Strong push of cold advection looks to wrap into the region Tuesday
evening into Wednesday...though there are big differences among
guidance regarding the depth of the upper low over Ontario (closed
or not). This will have a big impact on wraparound lake enhanced
precipitation potential...as the airmass will be plenty cold for a lake
component...but without deeper moisture...any showers will be of the
lighter variety. In addition...the depth of that system will have an
impact on just how strong the winds will be...with the operational
GFS and its ensembles supporting a stronger solution and tighter
gradient/strong winds overhead...while the European model (ecmwf) has been rather
steadfast on a more open upper wave and weaker surface low just to
Wednesday night-friday: looking seasonably chilly as we bid farewell
to October. As has been mentioned quite a bit recently...still some
big differences regarding just how much cold air will dump into this
portion of the country into late week or next weekend. Trends of
late (i.E. The past 12 months) would suggest a deeper solution is
likely to win out...though the recent trend toward persistent
troughing toward the Gulf of Alaska and western Continental U.S. Suggests the
best height falls/temperature anomalies may just scrape the area and really
impact the eastern lakes and northeast Continental U.S.. in either case...no
big signs of additional warmth...with temperatures generally below normal
to wrap up October.
Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 636 am EDT Sat Oct 25 2014
..clearing fast and turning gusty...
A cold front was rapidly approaching from the west...pushing
through the northwest lower airports over the next 1-2 hours. Warm air advection ahead
of the front was eroding all stratus faster than thought...and the
increasing winds will be felt primarily behind the front. Expect
winds to shift out of the west-northwest/northwest this morning with gusts reaching
25kts or slightly higher at times. Gustiness will continue into
tonight with skies being VFR clear for most of this taf period.
Maybe some scattered 4-5kft clouds late tonight.
issued at 347 am EDT Sat Oct 25 2014
Updated: went ahead and extended all nearshores through Sunday
night for wind and continued choppy waves
..high end small craft advisories everywhere...
SW winds are racing up through Lake Michigan right now...with some
sporadic advisory level gusts seen in surface observation. This also in
conjunction with some low cloudiness and maybe some isolated brief
spits of drizzle. This will rapidly change this morning...as a cold
front will race across the lakes this morning. Winds will quickly
shift out of the west-northwest/northwest and become quite gusty is slowly decreasing
stability. Advisory level gusts are a given....and there may also be
some isolated gale force gusts too. This would be more likely in the
coastal convergence locales from The Straits through Presque Isle
light....as we as across Whitefish Bay. Will hold off on any
issuances of gales just yet.
Advisory guts will continue through tonight...and gradually weaken
heading through Sunday...but some of these advisories will need
extensions in time due to not just wind...but also wave action.
High pressure then moves into Sunday and Sunday night. Maybe some
additional advisories will be possible for Monday-Tuesday.
LH...Small Craft Advisory until 6 PM EDT Sunday for lhz345>349.
Lm...Small Craft Advisory until 6 PM EDT Sunday for lmz323-341-342-
Ls...Small Craft Advisory until 6 PM EDT Sunday for lsz321-322.