Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 282344

Area Forecast Discussion
National Weather Service Marquette MI
744 PM EDT SAT MAY 28 2016

.SHORT TERM...(This evening through Sunday)
Issued at 245 PM EDT SAT MAY 28 2016

SSW upper flow still in place. Primary upper low is centered over
eastern SD with 1007mb sfc low over far northwest IA. Subtle warm
front arcs ahead of the sfc low, but it remains humid even north of
warm front with dwpnts in the low to mid 60s over Upr Michigan. Weak
shortwave and slight elevated instability with mucape up to 500j/kg
is supporting scattered showers over west cwa. Additional isolated
showers are affecting the far eastern cwa. Min in showers is noted
over central U.P. thus far. Radar trends and HRRR and RAP suggest
current pattern should hold for most part into the evening. There
has been no tsra yet as clouds have held down temps and instability.
Cannot count it out as there are tsra now forming upstream in WI.
Will keep isolated mention of tsra. Seems greatest chances for rain
and thunder into early evening will be over western Upper Michigan.

On a side note, latest flash flood guidance over western U.P. is
lower than points over central and eastern cwa - around 1.5-2.0
inches for 1 or 3 hours as there has been greater coverage to rain
there last few days. Any stronger storms could produce heavy rain
with 12z GRB sounding showing PWATS over 1.50 inches or over 200 pct
of normal. K-index was 34. Will be something to keep eye on as the
aftn goes into the evening.

Another mild night with lows in the upr 50s to low 60s. No need to
alter current persistent pattern with fog/stratus forming late
tonight and lingering into Sunday morning. Could see increase in
showers late tonight over sw as upper trough over SD moves to MN/WI.
Sfc low will be sliding over western U.P. during that time. Better
chances of showers and some thunderstorms will be later Sun morning
through Sun aftn with upper trough axis moving overhead and as
sfc-h85 trough axis crosses. Since low clouds should be around to
start day, could again see situation like last couple days where
instability forecast by models may be held down which will lead to
less chance of tsra. Proximity of mid level trough axis may lead to
higher lapse rates though since dry slot on leading edge of trough
(which has helped form tsra this afternoon over southern MN into
northern IA) will be pretty much east of cwa by aftn think that may
be where greater tsra chances will reside. Overall will keep thunder
chances low. Finally, once the sfc low and sfc-H85 trough pass by
expect strong/gusty west winds to develop over Lk Superior and
Keweenaw Peninsula. As the winds shift west and bring in slightly
drier air, should finally begin to scour out the fog over Lk
Superior. High temps on Sunday with plenty of clouds should reach
upper 60s to low-mid 70s with warmest readings south central and east
away from Great Lakes.

.LONG TERM...(Sunday night through Saturday)
Issued at 255 PM EDT SAT MAY 28 2016

Nam forecasts a 500 mb shortwave over the area 00z Mon followed by a
shortwave ridge that moves in on Tue. GFS and ECMWF show about the
same thing as well and will go with a blend of them for this
forecast. Pops move out Sun night and do not return to the cwa until
Tue. Looks pretty quiet and will still continue the dry forecast for
Memorial Day and Mon night. Overall, did not make too many changes
to the going forecast.

In the extended...GFS and ECMWF show a closed 500 mb trough and
closed low over the northern plains 12z Wed. This trough moves into
the upper Great Lakes 12z Thu and remains over the area through Sat.
Still remains unsettled this forecast period with temperatures
remaining near normal. Fri looks to be the driest day of this
forecast period with sfc high pressure in the area. Sat could have
some lake breeze convection with light winds and a warm front near
the area.

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 744 PM EDT SAT MAY 28 2016

LIFR clouds returned to KIWD late this afternoon and will persist
through the night with a few periods of IFR ceilings when the
occasional shower moves through. KSAW has broken out but will see
sky conditions deteriorate over the next few hours as more cloud
cover moves in with possibly a shower or two. KCMX has also broken
out to VFR but this will be ending within an hour or two as stratus
moves in and visibilities begin to decrease. IFR/LIFR conditions
will be the rule through the forecast over KIWD and KCMX. KSAW will
see a brief period of MVFR ceilings late Sunday morning and
afternoon along with increasing chances of showers and possibly a

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 245 PM EDT SAT MAY 28 2016

A relatively weak pres gradient/hi stability will dominate the Upper
Great Lakes this forecast period, so expect winds at or below 20kts.
Since moist air will linger over the chilly lake waters, dense fog
will persist into at least Sun. Will continue going Dense Fog
Advisory thru the day on Sun. The fog should begin to diminish Sun
night/Mon as drier air arrives from the NW.

Upper Michigan...
Lake Superior...
  Dense Fog Advisory until 6 PM EDT Sunday for LSZ243>246-264>267.

  Dense Fog Advisory until 2 PM EDT /1 PM CDT/ Sunday for LSZ162-

Lake Michigan...


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