Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 140843

Area Forecast Discussion
National Weather Service Gaylord MI
443 AM EDT Mon Aug 14 2017

.NEAR TERM...(Today through Tonight)
Issued at 336 AM EDT Mon Aug 14 2017

...Increased shower/thunderstorm chances today...

High Impact Weather Potential...thunderstorms are likely today
into this evening. A few stronger storms possible.

Pattern Synopsis/Forecast...Some semblance of an omega blocking
pattern is in place across NOAM this morning with the eastern
anchoring closed low still in the Hudson Bay region. Broad surface
high pressure spans much of the eastern CONUS with overall quiet
weather continuing across northern Michigan...although quite a bit
of high cloud cover is streaming through the region and there is
some spotty elevated radar returns on radar due to increasing
warm advection forcing.

Meanwhile...a couple short waves of interest within the broader
trough pattern. One fairly strong wave (and attending showers/storms)
is moving eastward through Minnesota...and a second wave (with
additional showers/storms) slipping southward through far western
Ontario. These two waves will phase but dampen while moving
through the Great Lakes later today and tonight.

Primary Forecast Concerns...Shower and thunderstorm chances
through tonight.

Today starts out fairly quiet with a fair amount of high cloud
cover...although there may be some spotty warm advection
showers/sprinkles already moving through the region this morning.
Aforementioned short wave phasing will be slow to develop...with
the main vorticity axis/QG-forcing for ascent and attending precip
just moving through Wisconsin by the end of the afternoon.
But...we will see increasing southerly flow/warm and moist
advection ahead of the trough into the region...kicking surface
dewpoints into the upper 50s/lower 60s with the higher dewpoints
pooling across NE lower Michigan. Forecast soundings this
afternoon suggest as much as 1200 J/KG MLCAPE across NE lower
Michigan. Larger scale synoptic forcing remains upstream through
the afternoon. But with the development of the typical smaller
scale low level convergence axis across NE lower Michigan...showers
and some thunderstorms are certainly a good bet...particularly
east of I-75.

Severe thunderstorm threat is not great...but better than in
recent days with not-to-shabby instability...mid level winds
increasing through the day to 20 to 30 knots...freezing levels
hovering around 10K FT and a bit of an inverted V look at the
bottom of the soundings supportive of gusty winds. SPC DAY 1
outlook keeps us in general thunder...but I will mention a few
stronger storms possible this afternoon across NE lower Michigan.

Tonight...phasing short wave trough slated to cross through the
region later this evening and overnight. With daytime heating...
anticipate additional/renewed convective development across
Wisconsin into Iowa/Illinois today ahead of the wave...with
diminishing convection crossing through lower Michigan tonight.
Hi-res guidance suggests this will be mainly south of M-72...but
we will just have to see how things evolve as we go through the


.SHORT TERM...(Tuesday through Wednesday)
Issued at 336 AM EDT Mon Aug 14 2017

Perhaps a leftover shower across eastern zones Tuesday morning,
otherwise ridging at the surface and aloft through Wednesday morning
should ensure precipitation free conditions. The next trough will
start to bring chances for showers across southwest zones late
Wednesday. Continued temperatures of right around climo (some spots
a little above Wednesday).

.LONG TERM...(Wednesday night through Sunday)
Issued at 336 AM EDT Mon Aug 14 2017

...Potential for heavy rain Wednesday night into Thursday...

Pacific energy is expected to carve out another trough which will
increase shower and thunderstorm chances through Friday. There is
even a decent chance for heavy downpours Wednesday night into
Thursday as precipitable water values climb to near 2 inches.
Another northern stream trough may lead to a few showers Saturday as
well. Short wave ridging will likely end the precipitation threat
for Sunday. Temperatures should be within a couple of degrees either
side of climo.


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 443 AM EDT Mon Aug 14 2017

Low pressure in the upper Midwest this morning will slowly move
through the Great Lakes through tonight. Ahead of this
system...increasing humidity will lead to shower/thunderstorm
development across parts of northern lower Michigan
today...particularly across NE lower Michigan and impacting the
APN terminal site. Another batch of showers will slip through the
region tonight...but may impact areas south of M-72.

VFR conditions through today...although with brief MVFR conditions
at APN in any showers/storms. Patchy to areas of fog anticipated


Issued at 336 AM EDT Mon Aug 14 2017

Winds and waves will remain below small craft advisory criteria
through midweek. Thunderstorm threat will increase on Lake Huron
this afternoon with a few stronger storms possible...which could
produce locally higher winds and waves. Diminishing shower/
thunderstorm threat tonight into Tuesday.




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