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Area forecast discussion 
National Weather Service Marquette Michigan
109 am EDT sun Jul 5 2015

Short term...(this evening through sunday)
issued at 319 PM EDT Sat Jul 4 2015

Latest water vapor imagery and rap analysis show a shortwave trough
extending from western Quebec to the lower Great Lakes. Upstream...
shortwave ridge axis is building in from northwest Ontario and northern Minnesota. At
the surface...a weak surface high pressure ridge has settled into the upper
Great Lakes. The lake fog which rolled into eastern Upper Michigan earlier
this morning has since burned off. The near calm winds and moist dew
points have allowed fog to linger over the lake into the afternoon
hours. Looks like a combination of cirrus clouds and smoke from
wildfires over northern Canada continues to spill over middle-level ridge to
west and into the upper Great Lakes bringing mostly cloudy skies to
much of the forecast area this afternoon. Despite cloud cover...temperatures
have reached into the 70s across much of the area...except right
along the Lake Superior shoreline. Some weak instability over the
scntrl forecast area (mainly Menominee and Dickinson counties) of a few
hundred j/kg could maybe trigger an isolated shower late this
afternoon/early evening along a lake breeze boundary off the Bay of
Green Bay. Otherwise...expecting dry conditions.

Should be a nice night for 4th of July activities including
fireworks. Really the only concern is whether lingering marine fog
along Lake Superior shoreline areas will push out away from
shoreline areas by late evening. Anticipate this will happen with
onset of return southerly flow as the high pressure ridge shifts east and
cold front pushes out over the northern plains. Lows tonight will be
mainly in the 50s though developing S winds should hold temperatures up in
the lower 60s over portions of the west while portions of the east will slip
below 50f closer to departing high pressure.

Rising heights aloft on Sunday and warm front well to the north of
Upper Michigan should lead to a very warm day away from Lake Michigan
under mostly sunny skies. With 850 mb temperatures topping out at 16-18c and
possibly high as +19c over western County Warning Area...middle 80s seem like good bet
across the west half...with perhaps a reading or two approaching 90f
for downsloping areas along Lake Superior.

Long term...(sunday night through saturday)
issued at 250 PM EDT Sat Jul 4 2015

A front will stall over the western County Warning Area (exactly where is uncertain)
between a shortwave moving across Canada and a surface low developing
over the the Central Plains in response to a potent shortwave moving
across the northern plains. Showers and thunderstorms should move over
either Western Lake Superior or far western Upper Michigan depending on where the
front stalls.

There are small differences in timing/track/strengh of the surface
low...but the general consensus is the low will deepen to 999mb as
it tracks up the stalled front over western-Northern Lake Superior or far western
Upper Michigan. While the 12z/04 NAM made a jump away from the previous
run in bringing precipitation into the central County Warning Area much earlier Monday...the
previous NAM and current European model (ecmwf)/GFS/Gem-NH show most of the precipitation
staying along the stall front and along and behind the surface low and
associated cold front stretching south-southwest from the low. With precipitable waters in
excess of 2 inches and strong flow from the S/southeast ahead of the
low...heavy rain is expected. The most prolonged heavy rain and
greatest quantitative precipitation forecast totals are currently expected over the Minnesota arrowhead
and/or western-Northern Lake Superior...along and west of the stalled front. By
time the precipitation surges into Upper Michigan...the cold front will be
moving quickly as the low shunts quickly NE...so prolonged heavy
rain will not be an issue over most land areas. The western u.P. Should
see the greatest quantitative precipitation forecast totals due to proximity of the stalled
front/surface low track/incoming shortwave...with possible totals around
1.5 inches. Elsewhere...a quarter to half inch of rain is possible.
Severe potential is uncertain as cloud cover will limit full surface
heating potential and also since the shortwave will be lagging behind
the low/front...limiting middle level lapse rates and thus instability.
However...with the projected magnitude of low level flow and deep
moisture/convection...precipitation loading may be able to force
gusty winds to the surface under heavier convection. The severe wind
potential will continue to be monitored closely. Winds will be stiff
out of the S ahead of the low...with 925mb winds around 50kts over
and north of Lake Michigan. However...do not expect gust potential in
that area as very stable conditions will exist over Lake Michigan
(850mb temperatures around 18c) and will be advected across eastern Upper Michigan. Do
expect southerly gusts to 30- 35mph to maybe 40mph over all of Upper Michigan
ahead of the low. Behind the system...northwest gusts of 30-35kts are
possible as cold air advects in...strongest winds will be near Lake
Superior. Increasing cloud cover and steady southerly winds Sun night will
keep low temperatures in the 60s west to 50s east. Highs will be in the low 80s
south central and in the 70s elsewhere.

A surface ridge will move over the area by 00z Wednesday...but before then fog
may develop on Lake Superior after the rain...possible invating
areas along Lake Superior into Tuesday. Highs will be in the 50s near
Eastern Lake Superior and in the 60s to around 70 elsewhere as skies
clear.

Looks like clear skies for Tuesday night so temperatures will have ample
opportunity to drop under the light flow and dry airmass. Think the
previous shift had the right idea in lowering temperatures...so will
continue that trend. Could see lows below 40 in some spots.

Overall...should see a warming trend Wednesday through Sat and a lack of
obvious forcing features will limit widespread precipitation potential.
Will use a consensus blend for this time period.
&&

Aviation...(for the 06z tafs through 06z Sunday night)
issued at 106 am EDT sun Jul 5 2015

High pressure over the area will gradually shift to the east today...but
will continue to bring VFR conditions through the forecast period. Light
winds overnight will become srly today and may become gusty in the
afternoon.
&&

Marine...(for the 4 PM Lake Superior forecast issuance)
issued at 319 PM EDT Sat Jul 4 2015

Light winds under 15kt will prevail through this evening under high
pressure. As the high departs and a cold front moves out over the northern
plains...winds will begin to increase some late tonight...but more
so sun/Sun night as the front moves closer. S to southeast winds ahead of
the front sun will gust up to around 20kt in the afternoon over the east
half of the lake. While stability over the water will limit winds
closer to the water surface...would not be surprised to see the highest
observation platforms get winds gusts to around 30kt Sun night/Monday
morning...perhaps even reaching gale gusts. The strong cold front
will Cross Lake Superior Monday aftn/evening...bringing a wind shift to
the northwest at 15-25kt. Given the unusual strength of the front for
summertime...there may be a period of wind gusts to 30kt and perhaps
even gale force for a brief time immediately after the front passes.
The strongest winds will affect the central and eastern portion of Lake
Superior. Winds will diminish later Monday night through Tuesday and will
become light Tuesday night into Thursday as high pressure builds over the upper
Great Lakes.

Will continue dense fog advisory into this evening over the east
half of Lake Superior with idea that increasing winds late tonight
into Sunday should help thin fog by that time. Fog will likely
develop again Sun night/Monday as rain showers/thunderstorms overspread the area ahead
of the cold front passage on Monday.
&&

MQT watches/warnings/advisories...
Upper Michigan...
none.
Lake Superior...
none.
Lake Michigan...
none.
&&

$$

Short term...Voss
long term...Titus
aviation...jlb
marine...Voss

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