Area Forecast Discussion
Issued by NWS Marquette, MI

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856
FXUS63 KMQT 232203
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
603 PM EDT MON MAY 23 2016

.UPDATE...
Issued at 601 PM EDT MON MAY 23 2016

Bumped up pops for showers/TS over the far wrn CWA where latest SPC
mesoanalysis indicates MUCAPE up to 1000 j/kg under sharp gradient
of pwat. Still looks like the more numerous showers/TS wl stay over
wrn Lk Sup. With effective lyr shear no more than about 25-30kts,
severe TS are not likely.
&&

.SHORT TERM...(This evening through Tuesday)
Issued at 223 PM EDT MON MAY 23 2016

Upper air pattern consists of a closed 500 mb low over southern
Saskatchewan with a trough in the northern rockies, a closed low
along the mid atlantic seaboard and a 500 mb ridge over the upper
Great Lakes. A shortwave will eject out of the central plains this
afternoon and will head northeast and affect the area tonight and
bring with it some convection. This shortwave will also help to
flatten the ridge over the area. Nam brings in some weak 850-500 mb
q-vector convergence with a narrow ribbon of deeper moisture moving
through the western cwa tonight and then across the ern cwa on Tue.
Overall, the going forecast has things pretty well in hand and did
not make too many changes to the going forecast. Kept temperatures
about the same. One thing I did do is cut back the pops a bit and
moved them further back a couple hours as the airmass is very dry
and will take a while to moisten up.

As for fire weather, will continue to let the red flag warning
continue through 8 pm as winds will finally die down and
temperatures will fall a bit, so relative humidities will slowly
increase this evening.

.LONG TERM...(Tuesday night through Monday)
Issued at 353 PM EDT MON MAY 23 2016

Several chances for rain/storms with temps running slightly above
average through the upcoming weekend.

Overall, a difficult forecast with very little confidence in terms
of precip timing through the period. The pattern will be dominated
by a large trough across the west half of the U.S., and a large
ridge across the east half of the U.S. Several short-wave troughs
are progged to eject from the western trough and round the eastern
ridge. Upper MI will be near the top of the ridge, so any energy
will produce showers and some thunderstorms. There is little
opportunity to improve on model consensus data beyond mid-week as
the timing/magnitude of each wave vary considerably among individual
models.

At this time, conditions look mostly dry Tuesday night into
Wednesday after frontal precip clears the SE CWA, though some
terrain-induced drizzle may occur central and east for the N to NW
wind belts of Lake Superior. With the front stalling just to the
south and with a stout subsidence inversion taking hold, low clouds
should hang around for much of Wednesday across the south half.

Solutions diverge considerably by late Wednesday as the first
shortwave arrives. The GFS and Canadian GEM favor a flatter ridge to
the east, bringing the shortwave across the SE half of the CWA. The
ECMWF and NAM favor a sharper eastern ridge, bringing the main
precip to the NW CWA and northern MN. QPF guidance ranges from less
than 0.1" to 1.5" Wednesday night. Given the amount of convective
feedback that will likely occur across the Plains Tuesday night into
Wednesday, it is nearly impossible to pick a viable solution.

Chances for showers and some storms continue through the weekend,
with the best chances on Saturday as a larger portion of the trough
lifts across the Upper MS Valley.

With the lake of appreciable large-scale dynamics and instability
through the period, any storms should stay below severe limits.
However, if daytime heating and the timing of shortwaves line up,
some strong storms cannot be ruled out from time to time.
&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 101 PM EDT MON MAY 23 2016

With daytime heating, the strong southwest winds just above the
surface based inversion will mix out and result in gusty winds into
this evening. Since the SSW flow will be tapping dry air, VFR
conditions will prevail until late tonight. Some shra/perhaps a TS
may move into IWD/CMX this evening and to SAW late tonight. With the
greater moisture and pcpn, MVFR cigs are also expected into CMX/IWD
late tonight and at SAW Tue morning.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 223 PM EDT MON MAY 23 2016

Southerly winds of up to 25 knots are expected through this evening
as a low pressure trough approaches from the west. The trough will
stall over the Upper Great Lakes Tuesday through Friday, bringing
winds generally under 20 knots.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Red Flag Warning until 8 PM EDT /7 PM CDT/ this evening for
     MIZ001>015-084-085.

Lake Superior...
None.
Lake Michigan...
None.
&&

$$

UPDATE...KC
SHORT TERM...07
LONG TERM...Kluber
AVIATION...07
MARINE...07



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