Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 230230

Area Forecast Discussion
National Weather Service Gaylord MI
1030 PM EDT MON AUG 22 2016

Issued at 1024 PM EDT Mon Aug 22 2016

Forecast continues to get a touch more challenging heading
through the remainder of the night...owning to that rather
organized convective complex making a run through central upper
Michigan and into northern Lake Michigan. This complex is on
the leading edge of h8-h7 theta-e advection and impressive
corridor of mid level lapse rates. Both of these gradients become
a touch more diffuse as they continue to advance east, supporting
most guidance progs of rather steadily decaying this convective
complex as it pushes into our area. With that said, simple
momentum supports a more aggressive shower/isolated thunderstorm
mention into the early morning hours...especially north of M-72.
Not expecting a ton of rain, and no severe weather threat with
rapidly decaying most unstable cape profiles. No doubt, however,
future amendments to the forecast will be needed as radar trends
our better realized.


.SHORT TERM...(Tonight and Tuesday)
Issued at 329 PM EDT Mon Aug 22 2016

High impact weather potential: slight chance of non-svr t-storms
tonight Straits area and eastern upper MI.

High pressure is centered in far southern IN. As the high continues
to move up the Ohio Valley and toward the northeast states, warm
advection will increase. Precip chances may emerge tonight as warm
advection initially ramps up.

Tonight...consistent signal from the short term guidance that
stronger warm advection will trigger some showers over western/
central upper MI near or just after sunset. This actually occurs in
an environment of almost negligible instability (mlcape 300j/kg or
less). However, a plume of 700-500mb lapse rates approaching 7c/km
tries to advance eastward into the western lakes (it never quite
gets here though). The Nam/Rap/HRRR all offer up rather similar
solutions, and if anything the Nam is the slowest/driest of the
models. With a consistent model suite, will increase the chance of
rain somewhat tonight, with late night pops as far se as a TVC-
Rogers City line. However, the limited instability should make it
difficult to realize any thunder from this activity. Expect this
activity to fade out toward sunrise as warmer/drier mid-level air
arrives. Despite the lack of progged instability, will maintain a
slight chance of thunder from the Straits region northward.

Min temps in the mid 50s to mid 60s (warmest near Lake MI).

Tuesday...a deep warm/dry airmass will continue to enter the region
from the sw. Anticipate any showers tonight getting wiped out before
12z, and no precip after. Lingering altocu/altostratus (especially
in central/northern sections) will be eroded fairly quickly in the
morning. That will result in abundant sunshine from late morning on,
with less in the way of cumulus than today. Warmer max temps, near
80 to the mid 80s, and a few upper 80s possible in ne lower MI. Will
see a breezy sw wind gusting to 15-25mph, gustiest near Lake MI and
in the far se.

.LONG TERM...(Tuesday Night through Monday)
Issued at 329 PM EDT Mon Aug 22 2016

Weather Impacts:  Minimal, with only some mid-week thunderstorm

Synoptic pattern: Upper trough initially over the Rockies and
western High Plains will migrate eastward through the period, as an
associated surface front (anchored to low pressure over southern
Canada) moves across the Plains and Upper Mississippi River Valley,
and eventually reaches the Great Lakes by late Wednesday.  This
system will provide our next chance for precipitation on Wednesday.

Tuesday Night and Wednesday:  Surface high pressure over the mid
Atlantic states, coupled with upper ridging over the eastern Conus,
will provide the Great Lakes with deep southwesterly flow. And not
too surprising, moisture will be on the increase. Models are in good
agreement that a short wave trough, and area of large scale forcing
for ascent, will eject out of and precede the aforementioned upper
trough to our west, bringing a chance for convection by Wednesday
(especially Wednesday afternoon over western/northern parts of
forecast area). Though 850 mb dew points should surge toward +15C
during the day, models are really keeping the best instability well
south and west of the region.  This, coupled with 500 mb flow
forecast generally in the 30-35 kt range, suggests any severe
weather should remain limited.  Highs Wednesday should reach 70s to
around 80.

Wednesday Night and Thursday:  Aforementioned upper trough will push
east-northeastward across upper Great Lakes and reach central
Ontario by late Thursday. At lower levels, model pressure fields are
somewhat nebulous.  It appears region will remain in a warm and
juicy air mass, and that the boundary layer flow will remain
somewhat cyclonic (suggesting support for additional convection).
However, lead trough passing through late Wednesday may limit
convergence heading into Wednesday Night.  Then by Thursday there
are some hints (particularly with the GFS) that additional
convection may fire as front finally moves through - though eastern
and southern areas may be most prone to additional showers as cool
air advection starts to kick in later in the day. Highs Thursday
will once again reach the 70s to around 80.


The passage of a cold front Thursday night will bring a chance of
precip, but afterwards, high pressure builds into the Great Lakes
from the Plains thanks to the persistent ridge in the southeastern
part of the country. This pattern will hold for most of the weekend
before a few shortwaves try to swing in ahead of a trough Sunday
into Sunday night. This will bring a chance of showers for Sunday as
a warm front at the surface slides down into the region from
Ontario. Temperatures for the weekend will be just above average for
this time of year and will be on a steady rise from the mid 70s
Friday to low 80s by the start of the work week.


.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 744 PM EDT Mon Aug 22 2016

Forecast becoming a touch more challenging heading through the
overnight, all tied to blossoming complex of upstream convection.
This will translate east, although do believe it will decay with
time. Still thinking high based activity, maintaining vfr
conditions at all taf site through the overnight. Will continue to
monitor of coarse, with the most likely spot for any significant
impact at KPLN. Skies clear again Tuesday as dry air invades the

Winds generally light tonight, becoming gusty out of the southwest
on Tuesday. Couple hours of late night wind shear possible for
KPLN only.


Issued at 329 PM EDT Mon Aug 22 2016

High pressure over the Ohio Valley will move off to the east and
ne, with strong sw low-level flow on its backside. Gusty sw winds
will persist into Tuesday, with small craft advisories already
issued for many waters.


.APX Watches/Warnings/Advisories...
LH...SMALL CRAFT ADVISORY until 6 PM EDT Tuesday for LHZ345.

     SMALL CRAFT ADVISORY from 8 AM to 6 PM EDT Tuesday for LHZ346-

LM...SMALL CRAFT ADVISORY until 6 PM EDT Tuesday for LMZ323-341-342-

LS...SMALL CRAFT ADVISORY until 6 PM EDT Tuesday for LSZ321.



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