FXUS63 KAPX 140457

Area Forecast Discussion
National Weather Service Gaylord MI
1257 AM EDT Mon Jun 14 2021

Issued at 903 PM EDT Sun Jun 13 2021

Upstream surface low has reached the far western shore of Lake
Superior late this evening. Area of convection continues to
develop along and just NE of the associated warm front.
Strengthening mid level jet max and modest instability axis has
aided in the development of a fast-moving thin line of well-
organized thunderstorms which has now reached Green Bay. A few
additional thunderstorms have developed in its wake across far
Northern Wisconsin...again feeding off the strengthening mid level
winds. Low levels remain rather dry...so thunderstorms are high-
based with the primary threat being gusty winds. Upstream reports
have featured wind gusts to 40 mph and half inch hail so far.
Convective development/propagation is favoring the southern end of
the convective line where better instability resides...with
periodic bowing segment development as well. Will continue to keep
a close eye on this convection as it enters Lake Michigan and
eventually Northern Lower Michigan. Have made some minor
adjustments to POPs for the rest of the night...but overall expect
chances of showers will expand eastward thru much of our CWA
tonight...certainly with chances of embedded thunder. Winds across
our CWA will be significantly weaker than upstream...so expect an
overall downward trend in intensity of this convection as it
reaches our area. Also...loss of diurnal instability should aid in
this general trend.


.NEAR TERM...(Through Tonight)
Issued at 137 PM EDT Sun Jun 13 2021

...Some showers tonight...

High impact weather potential: Minimal. May see an isolated
thunderstorm or two this evening, but nothing severe expected.

Pattern synopsis and forecast:

Mid and upper level flow amplification well underway early this
afternoon...driven in large part by northward expanding ridge axis
extending from Mexico to northern Ontario. Troughing and attendant
northwest flow on the downstream side of this ridge developing into
the Great Lakes, bringing a gradual end to the recent warm and
muggy conditions. At the surface, high pressure centered across
the northern Great Lakes, as evident by dry conditions and plenty
of sunshine. Shortwave trough on exit region of 120+ knot upper
level jet digging rapidly southeast just northwest of Lake
Superior, kicking off an area of showers as it does so.

Pattern will continue to amplify heading into this work week, with
deep troughing becoming increasingly established across northeast
NOAM...including the eastern Great Lakes. Upstream wave will continue
to dig southeast in this amplifying regime, cutting across our
area tonight...with yet another wave dropping south into the area
on Monday.

Primary forecast concerns/challenges:

Addressing shower/storm threat into this evening with passage of
that lead wave.


Band of showers will drop southeast through the area later this
afternoon into tonight. Greatest forced ascent via weak low level
jet and favored exit region upper jet dynamics expected to target
mainly northern lower Michigan...especially around the Grand
Traverse Bay region and points southwest. Expect shower coverage and
organization to be greatest in this area, with perhaps even a rumble
of thunder or two given some limited instability. Unlike the last
few days, not expecting any of these storms to become severe.
Primary forcing exits with time overnight, taking the better shower
potential along with it, with perhaps just a few light showers
lingering far southeast by sunrise Monday.


.SHORT TERM...(Monday through Wednesday)
Issued at 324 AM EDT Sun Jun 13 2021

...Cooler temps and dry weather ahead...

High Impact Weather Potential: Low

Pattern Synopsis:

Dominant upper-level ridging centered over the 4 Corners will
amplify across the Rockies into much of Canada through the first
half of the week. Downstream, troughing will dip across the Great
Lakes and NE CONUS. Strong surface high pressure will build across
Hudson Bay and push into the Great Lakes by Wednesday.


After the trough axis pivots across the area Monday morning, broad
subsidence will encompass the Great Lakes through the beginning of
the week. Northerly low-level flow induced by high pressure near
Hudson Bay will advect cooler, drier air into the region for several
days. This, in tandem with subsidence aloft, will keep precip
chances at bay through Wednesday. There is a chance for isolated
showers near Saginaw Bay in association with lake breeze formation
Monday afternoon, but a very dry low-level airmass will make CI
difficult. Aside from this, highs in the low to mid 70s are expected
underneath sunny afternoon skies. Dewpoints dipping down well into
the 30s will prevent afternoons from feeling muggy, but will
reintroduce fire weather concerns to areas that have seen little/no
rainfall since the beginning of the month. Aforementioned
temperatures combined with sustained winds near 10-15 mph and RHs in
the teens and 20s will certainly create wildfire danger in areas
with very dry vegetation - particularly those across NW lower
stretching east along M-32 towards Alpena.

.LONG TERM...(Wednesday night through Sunday)
Issued at 324 AM EDT Sun Jun 13 2021

High Impact Weather Potential: Low for now

Shortwave ridging will slide across the Midwest on Thursday while
amplified troughing pushes off the Atlantic coast. A shortwave/jet
max looks to progress across the northern Great Plains and into the
Great Lakes in the Friday/Saturday timeframe, providing support for
a cyclone that should trek across northern Ontario/Quebec. Induced
southerly winds will attempt to advect moisture northward into the
region ahead of the aforementioned shortwave/jet max, but relatively
little time may exist to get dewpoints conducive for thunder/severe
potential far enough into the Great Lakes before precip arrives
Thursday evening/Friday morning. While confidence in any higher
potential is very low as of now, ample shear aloft could support a
strong line of storms should any instability exist. Otherwise, this
round of precip will be the next rain chances for northern Michigan.
High temps near 80 are expected before cooling down a few degrees
over Father`s Day weekend.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1256 AM EDT Mon Jun 14 2021

Low pressure in SE Wisconsin will track just south of the Great
Lakes through today, before high pressure and much drier air
gradually work toward the region. Rain/showers impacting APN/TVC/MBL
will end by daybreak, with additional isolated showers and few
storms south and SW of APN this afternoon. So, no additional
rainfall expected at the airports from daybreak through tonight at
the airports. Northerly winds will remain a little gusty for a few
more hours, then become gusty again this afternoon out of the NW,
before dropping off tonight. CIGS will largely remain VFR over the
TAF period, with no expectations for VSBY reductions.


Issued at 137 PM EDT Sun Jun 13 2021

Despite a bit cooler airmass and tighter pressure gradient, generally
stable conditions will continue over the Great Lakes into the
start of the work week...helping to keep winds and waves under
advisory levels. A weak area of low pressure and cold front arrive
tonight, bringing additional chances for showers and perhaps a
rumble of thunder or two as well. This front will be followed by
another tightening of the pressure gradient for Monday, but speeds
are still expected to be below advisory criteria attm.





NWS APX Office Area Forecast Discussion