Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 281901

Area Forecast Discussion
National Weather Service Marquette MI
301 PM EDT Wed Jun 28 2017

.SHORT TERM...(This evening through Thursday)
Issued at 256 PM EDT WED JUN 28 2017

The break in precipitation across the U.P. is slowly coming to an
end, with a weather system approaching from the southwest this
evening. Visible satellite imagery shows an expansive area of cloud
cover across the Great Lakes/Upper Midwest; however, some clouds
have been able to erode with afternoon heating across portions of
Southern MN/IA/MO. Water vapor imagery indicates a lobe of vorticity
embedded within the inverted trough axis across Northeast Iowa,
which is closer to the greatest instability area of Eastern
Iowa/Northern Illinois/Southwest Wisc. Forecast guidance throughout
the day has maintained diffluent flow over the U.P. which is helping
to diminish the leading edge of precip, and this appears to be the
case through 21z. Heights are then progged to fall, with the vort
lobe lifting northeast across Central Wisc but also weakening. The
warm/moist conveyor if progged to lift north over Central/Eastern
U.P. with the steadier precip still positioned along a Menominee
County to Southern Luce County. As eluded to earlier, guidance has
been trending towards less QPF through the event. But this could all
depend on upstream convection, which is struggling at present to
develop. With more thunderstorm activity over Southern Wisc/Iowa/IL,
this would help to shunt the heavier precip axis further south. Have
trended lower with QPF as a reflection of this thinking, with
between 0.5" to 0.8" for Central/Western U.P. and 1" to 1.3" for
Menominee/Luce axis. There does remain some instability through the
profile overnight, mainly within the 00-06z timeframe, which could
still support some embedded or isolated convection. Given the moist
airmass, some brief heavier downpours is plausible and could easily
push QPF totals higher for those respective area.

Temps tonight will remain mild with the warm/moist airmass in place,
pushing dewpoints into the upper 50s to lower 60s. This will keep
overnight lows similar to Td`s. The baggy gradient may produce some
patchy fog as well, but this appears to be more focused in the
eastern CWFA after midnight.

Thursday...Trough axis will continue to pivot east, being overhead
of the U.P. around daybreak. Then continueing to push east
throughout the day, with height rises beginning to approach from
west to east by early afternoon. Dry weather is then progged to
return. Highs for Thur will warm into the upper 60s to lower 70s,
with areas adjacent to Lake Superior experiencing a shadow effect
and remaining several degrees cooler than inland locations.

.LONG TERM...(Thursday through Tuesday)
Issued at 337 AM EDT WED JUN 28 2017

Models indicate a slowly progressive pattern will prevail with zonal
flow during the middle of the week giving way to troughing through
the north central CONUS this weekend as a mid level low moves from
Alberta into the Upper Great Lakes. A ridge will then build from the
Northern Plains into the Upper Great Lakes for the first half of
next week. Temperatures will remain below normal with moderation
closer to seasonal averages early next week.

Beginning Thursday, Additional wrap-around moisture and light rain
could continue across the northern tier of the cwa into early
Thursday afternoon as the compact mid level low moves across eastern
Lake Superior. Ridging and q-vector divergence spreading in from
the west in the afternoon will lead to drier conditions.

Friday-Sunday, as the larger scale mid level trough deepens from the
Northern Plains into the Upper Great Lakes, a shortwave trough and
associated sfc low is expected to lift from the Central Plains into
the western Great Lakes. The models have trended farther north with
this feature and associated pcpn compared to previous runs. The
heaviest pcpn is again expected over southeast Upper Mi based on
model consensus track of the sfc low and fcst of stronger 305k-310k
isentropic ascent over se half of the cwa. With the mid-level trough
deepening over the northern Great Lakes, rain chances will increase
Saturday, especially inland during peak heating. Isolated t-storms
will also be possible se half as MLCAPE values approach 500 J/Kg.
Enough moisture/instability will linger into Sunday with cyclonic
mid level wnw flow and potential of weak shortwaves moving through
region to warrant low chc pops for mainly afternoon isold to
scattered showers.

Monday-Wednesday, Models and ensembles in good agreement with the
drying trend expected at least for the first half of next week as
mid-level and sfc ridging build into the area. Sunshine should push
temps well into the 70s with a gradual warming trend into Tuesday.

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 256 PM EDT WED JUN 28 2017

VFR conds are still holding at TAF sites; however, visible
satellite imagery indicates upstream OBS are lowering due to the
moistening airmass that is expected to arrive tonight. Leading
edge of precip has struggled to lift northeast towards IWD/SAW;
however, expect later tonight precip coverage to increase along
with intensity increasing. There does remain a possible
thunderstorms could approach IWD/SAW, but timing is currently
difficult to pin-down. VFR conds are expected to steadily lower
this evening, heading towards IFR CIGs with VSBYs holding around
MVFR. After 6z, the gradient becomes weak and this may allow CIGs
and VSBYs to fall further towards LIFR conds. After daybreak Thur,
CIGs/VSBYs will be slow to recover but expect precip to shift east
by mid-morning and VFR conds returning by 18z Thur if not slightly


.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 256 PM EDT WED JUN 28 2017

Ahead of a low pressure system the gradient increases over Lake
Michigan, with gusts approaching 25 to 30 kt at times this
evening/overnight. Across Lake Superior the gradient is not as
robust; however, winds may approach small craft advisory conditions
at times for portions of Lake Superior east of the Keweenaw
Peninsula. The low lifts northeast tonight, and could allow marine
fog to develop. With winds turning west/northwest, expect any fog to
be confined to the east given the short-window for development.


Upper Michigan...
  Beach Hazards Statement until 9 PM EDT this evening for MIZ014.

Lake Superior...
Lake Michigan...


SHORT TERM...Beachler
MARINE...Beachler is the U.S. government's official web portal to all federal, state and local government web resources and services.