Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 200751
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
351 AM EDT SAT AUG 20 2016

.SHORT TERM...(Today and tonight)
Issued at 351 AM EDT Sat Aug 20 2016

...Potent cold front swings through the region later today...

High impact weather potential: Showers and thunderstorms today
through this evening. Slight risk for severe storms.

Overview: Stalled front stretches from the James Bay region down
through central upper Michigan and through Wisconsin, to secondary
low pressure over Missouri. A warm and soupy airmass is in place
ahead of the front through the Mississippi River valley and into
the Great Lakes region. Overnight SPC mesoanalysis reveals decent
instability across the lower lakes and midwest. More stable up
this way with very subtle mid level ridging and a bit of a warm
nose noted above 600 MB on our 00Z sounding. But there is a
northward surge of more unstable air up through Wisconsin and far
western lower Michigan along the developing warm front and "warm
advection wing" of showers and few storms bowing northward into
the Ludington/Manistee area in the last few hours.

Upstream, anticipated potent short wave is digging into the midwest
toward Iowa this morning, and expected to begin to gin up strong
surface cyclogenesis in the midwest shortly.

Today: It`s gonna rain and storm, it`s just a matter of fine
tuning forecast timing to the extent possible. Upstream potent
short wave will advance into the midwest this morning before
swinging across the western Great Lakes later this afternoon and
tonight. Strong synoptic forcing (aided by a coupled upper jet
structure) will lead to impressive late August surface
cyclogenesis with an eventual sub 1000 MB surface low tracking
northeast across eastern upper Michigan by 06Z tonight (still a
little wobble amongst the various guidance tracks). This system
will drive a potent cold front through the region late this
afternoon through this evening and a north-south axis of
widespread showers/storms crossing the CWA.

Initially, will have to account for "warm advection wing" of
showers and a few storms arcing into northern lower Michigan.
Unclear just how far north/east this intial batch of precip will
get due to more stable conditions further north, and some high
resolution guidance has this stuff fizzling out over the next few
hours. But will carry some higher pops across the SW counties
early on and see what happens. Arrival of strong synoptic forcing
and approaching sfc low will drive axis of categorical showers/storms
into and across the region late this morning and through the
afternoon hours and have beefed up pops to flat out 100 percent.

Severe weather possibilities: Plenty of synoptic forcing and
kinematics at play with a nice QG-forcing bullseye swinging up
through northern Michigan (centered on the U.P) this afternoon and
mid level flow increasing to in excess of 50 knots ahead of the
front. Forecast instability this far north is not so impressive
however given rather anemic mid level lapse rates and a shortened
window for decent daytime heating. Nonetheless, increasing
effective bulk shear and arrival of strong synoptic support should
make up for a lack of big instability and lead to embedded multi-
cell storms with some rotation and damaging wind potential. Thus
SPC slight risk looks good and if we did have more instability we
would probably be in a higher risk today.

Tonight: Cold front will cross the region through the evening
hours and mark a west-east end to the precip. Behind the front,
gusty winds and strong cold advection will usher in +10C 850 MB
air, which given the very warm lake temps (> +23C) will likely
lead to some lake induced rain showers across NW lower Michigan,
along with a nice batch of deformation (wrap around) showers
slipping through upper Michigan. Welcome to our first taste of
fall.

.LONG TERM...(Sunday through Friday)
Issued at 351 AM EDT Sat Aug 20 2016

(8/21)Sunday...The 500 mb trough moves through the forecast area in
the morning so that the axis is east of the region around 18z, with
some residual moisture associated with the sfc low and the 500 mb
low. 850 mb temperatures fall quickly through the day from +7c to
around +6c and with the water temperatures around 22C in N Lakes
MIchigan and Superior, will expect that the LE rain will be the
result. However, as is usually the case with these types of early
season events, there won`t be much in the way of banding, and the
rain will be more like drizzle. Dry air begins to move into the
region after 00z, and the chances of rain begins to fall apart.

(8/22)Monday...For the most part, the only moisture in the region is
the 700-500 mb moisture associated with the warm advection wing
north of Upper Michigan during the afternoon. The lower levels (850
mb and below) show the RH<50% as the 850 mb temperatures warm up
again into the middle teens C. So the day itself looks dry. The
forecast becomes problematic overnight as the GFS and ECMWF both
begin to produce some rain under the 500 mb jet streak (40knots) and
along a weak baroclinic zone, mainly in Upper Michigan. Based on the
moisture profiles of the soundings, not impressed and have the
chances at slight for the most part.

Extended (Tuesday through Friday)...Tuesday, any rain in the
region lifts north as the 500 mb ridge begins to builds over the
region. Models break down the ridge and push the 500 mb trough
into the Northern Plains, this looks similar to the system that
is/will push through the the Upper Great Lakes now/and later
today. However, it looks like it pushes out of the region by
Thursday morning so that the Thursday and Friday turn out dry.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1158 PM EDT Fri Aug 19 2016

Just some isolated light showers expected for the remainder of
tonight. Otherwise, reduced vsbys with mist/fog expected once
again through the early morning. Widespread rain expected
Saturday, especially during the late morning and afternoon, with
conditions deteriorating to widespread MVFR with areas of IFR in
stronger storm activity. IFR/MVFR conditions to persist right
through Saturday evening.


&&

.MARINE...
Issued at 351 AM EDT Sat Aug 20 2016

Active weather for the next 36 hours with showers and storms
anticipated today through this evening, and showers persisting
through Sunday. Cannot totally rule out waterspouts tonight into
Sunday morning.

Gustier SW winds will develop today as a potent storm system
swings into the region. Strong cold front crosses the region
tonight and will usher in gale force wind gusts for some nearshore
areas. Will hoist gale warnings or small craft advisories for all
nearshore zones for later today through Sunday evening.

&&

.APX Watches/Warnings/Advisories...
MI...NONE.
LH...GALE WATCH from late tonight through Sunday afternoon for LHZ347-
     348.

LM...GALE WATCH from this evening through Sunday morning for LMZ342-
     344-345.

LS...GALE WATCH from late tonight through Sunday afternoon for LSZ321.

&&

$$

SHORT TERM...Adam
LONG TERM...JSL
AVIATION...MSB
MARINE...Adam



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