Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 270026

Area Forecast Discussion
National Weather Service Gaylord MI
826 PM EDT Wed Apr 26 2017

.NEAR TERM...(Tonight through Thursday)
Issued at 358 PM EDT Wed Apr 26 2017

...Several rounds of showers and storms through Thursday...

High Impact Weather Potential...Thunderstorms possible tonight and
Thursday. Stronger storms possible Thursday.

Pattern Synopsis/Forecast...Satellite/upper air obs reveal Long
wave troughing stretching down through central NOAM...downstream
from broad upper ridging in the eastern Pacific and a strong upper
jet plowing into the US west coast. Lead short wave and associated
surface low analyzed over Wisconsin with a cold front stretching
down through Illinois and the Mid Mississippi River Valley, with
an associated batch of showers advancing through the western Great
Lakes. Second stronger short wave and associated surface low is
in eastern Texas with it`s own area of showers/storms spanning
from east Texas northward into the Midwest.

Tonight through Thursday...precip chances will come in a few
different waves. Initially, lead short wave will swing rather
quickly up through northern Michigan into this evening with this
ongoing first batch of showers skirting through upper Michigan and
parts of northern lower Michigan. Per SPC mesoanalysis, only
limited instability out there this afternoon and no lightning
showing up on NLDN/ENTLN charts. There is a nice axis of steeper
mid level lapse rates draped across lower Michigan ahead of the
front. So I suppose it`s not impossible we see some isolated
thunder in the next few hours...primarily across northern lower

Meanwhile, second stronger wave near the Gulf coast this afternoon
is expected to swing up into the lower lakes region tonight and
through the Great Lakes on Thursday...with the parent long wave
trough deepening and becoming negatively tilted in time and strong
cold front finally crossing the region on Thursday. Upstream
showers/storms pushing into the Midwest will be expanding up into
the region later tonight (mainly overnight) with one more round of
showers/storms crossing the region on Thursday with the front.
Thunderstorms on Thursday may pose a marginal risk for severe
weather given steeper mid level lapse rates and rather strong
0-6KM bulk shear values in excess of 50 knots, particularly if we
can generate any surface based instability prior to FROPA.


.SHORT TERM...(Thursday night through Saturday)
Issued at 358 PM EDT Wed Apr 26 2017

...Lingering showers diminishing Thursday night...

High impact weather potential: None.

Pattern Forecast: By Thursday night, broad troughing is expected to
encompass the majority of the CONUS with post cold frontal cooler
air filtering in locally as the much advertised area of low pressure
affecting the region will be quickly shifting northward towards
James Bay. Question marks through the short term forecast period lie
within the Friday afternoon-Friday night time frame as high pressure
attempts to push into the region from the west while a shortwave
treks from the central plains into the Great Lakes. Troughing
deepens across the four corners region during the day Saturday with
cyclogenesis underway lee of the Rockies as energy shifts east
Saturday night...ultimately continuing our active pattern with
additional rain chances late in the weekend-early next week.

Primary Forecast Concerns: Diminishing PoP trends Thursday evening-
night followed by shower chances Friday afternoon-evening.

Post cold frontal airmass Thursday evening will certainly put the
chill back in the air with low temps Thursday night bottoming out in
the 30s area-wide. Lingering scattered shower chances across the
northern third of the area (primarily north of the bridge) will
continue to diminish Thursday evening into the early overnight
hours. Wouldn`t be shocked to see a transition to a bit of wet
snow/drizzle/freezing drizzle across sections of Chippewa County as
low-mid level thermal profiles continue to cool before precip comes
to an end. Doesn`t look to amount to much of anything, however...and
no real impacts are expected.

After a quiet, but cool start to the day Friday, confidence
diminishes Friday afternoon through evening as high pressure attempts
to nose in from the west while a weak shortwave approaches the
region from the southwest. Deterministic/ensemble guidance is nearly
split in the overall evolution of Friday and attendant shower
chances. Gut feeling is that at least scattered showers beginning
mid-late afternoon are able to sneak in to far southern areas of the
CWA...primary south of M-72, diminishing as you head toward M-32
before ending Friday night. Another day with a 20 degree spread in
high temps across northern Michigan, ranging from the mid 40s north
to the low-mid 60s near Saginaw Bay.

A brief reprieve from the active weather on Saturday, despite below
normal temps and increasing/lowering clouds ahead of the next
approaching system set to spread more wet weather across the region
Saturday night through the start of next week (talked about a bit
more below).

.LONG TERM...(Saturday night through Wednesday)
Issued at 358 PM EDT Wed Apr 26 2017

The overall theme for the extended period is cool and wet.  A closed
low slowly moves over the great lakes Sunday through Tuesday...with
considerably cooler temperatures and widespread periodic chances for
precipitation through this time. Models show this low sucking cold
Canadian air down across the lakes late Monday, with H8 temps of -4C
over the area into Wednesday. There is a chance, should pops line up
with diurnal lows, a few locations (particularly in the interior
higher terrain) could see a couple snowflakes before it`s over.
Guidance then shows moisture stripping out on Wednesday...but that`s
a long way off.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 826 PM EDT Wed Apr 26 2017

Low pressure over the Lower Mississippi River Valley will lift
northeastward into the lower Great Lakes region tonight and up
through Michigan on Thursday. This will bring a few rounds of
showers and some thunderstorms to northern lower Michigan...with
the first round arrival overnight tonight. Second round
anticipated late tomorrow morning into the afternoon as the front
crosses the region.

Mainly VFR conditions anticipated tonight into Thursday...although
there is some lower stratus just across Lake Michigan that could
make a run at MBL and TVC later tonight into Thursday morning.
But cigs should lower substantially on Thursday after FROPA with
cooler air slicing into the region.

Winds have and will settle down tonight but increase again on
Thursday particularly after the front passes through the region.
Not quite as gusty as today...but gusts to around 25 knots.


Issued at 358 PM EDT Wed Apr 26 2017

Gusty SE winds into this evening and gusty SW winds on Thursday
will lead to a prolonged stretch of small craft advisories on the
Great Lakes through early Friday morning.


LH...SMALL CRAFT ADVISORY until 2 AM EDT Friday for LHZ345>349.
LM...SMALL CRAFT ADVISORY until 2 AM EDT Friday for LMZ323-341-342-
LS...SMALL CRAFT ADVISORY until 2 AM EDT Friday for LSZ321-322.


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