Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 201922

Area Forecast Discussion
National Weather Service Marquette MI
322 PM EDT FRI MAY 20 2016

.SHORT TERM...(This evening through Saturday)
Issued at 320 PM EDT FRI MAY 20 2016

Weak split upper troughing affects eastern Canada to the lower Great
Lakes into Sat. Meanwhile, strong ridge from Central Plains to south
central Canada slowly will move toward Upper Great Lakes by late on
Sat. At the sfc, high pressure ridge overhead much of this week will
give way to weak trough crossing Lk Superior and Upper Michigan on
Sat. Continue to lean on GEM bias corrected guidance for min temps
over interior. Could see mid-upr 30s in favored cold spots. On Sat,
soundings look too dry for showers or tsra but could be sct-bkn mid
clouds as the trough moves through. Passage of trough will result in
nw winds and not as much of a lake breeze off Lk Michigan. Temps
will be cooler east half near Lk Superior. Temps over inland west
areas should rise to the upper 70s if not reach 80 degrees in a few
spots. Expect another day with low min RH values, down to 22 to 27
pct inland.

Instead of issuing a separate statement addressing the elevated
wildfire potential for the weekend, have included that hazard in the
fire weather watch that was issued for Monday.

.LONG TERM...(Saturday through Thursday)
Issued at 503 AM EDT FRI MAY 20 2016

Expect a slowly progressive pattern as the mid/upper level ridge
over the plains shifts through the Great Lakes and the western CONUS
mid level low over OR lifts to Saskatchewan leaving a broad trough
with wsw flow to the Upper MS valley and northern Great Lakes.
Temperatures will remain above normal with dry weather finally
giving way to increasing shra/tsra chances from Monday into Tuesday
with precipitation potential continuing through Thursday. Until
greater moisture and pcpn arrive, elevated fire weather risks will
be the main forecast concern.

Saturday, A shortwave trough and associated cold front will dive to
the southeast through northern Ontario but the pcpn chances are
expected to remain to the north and east of Lake Superior. Deep
mixing, with 850 mb temps around 10C-12C, will support max temps
into the mid and upper 70s and bring dewpoints down into the upper
30s, at the lower end of guidance. With the relatively dry low
levels, the pcpn produced by the GFS was disregarded.

Sunday, Temps should climb a few degrees as 850 mb temps climb 1C-2C
compared to saturday as RH values again fall into the 20-30 pct
range.  with the sfc ridge moving just to the east of the area late,
expect relatively light winds with lake breezes developing.

Monday, A tightening gradient between the ridge over the eastern
Great Lakes and low pressure over manitoba will result southerly
winds of 10 to 20 mph. With 850 mb winds around 25-30 knots, gusts
should climb into the 20 to 30 mph range, strongest over the west
half. Although low level moisture will be increasing across the
west, another day with min RH values from 25 to 30 pct is expected
over the central and east. With the stronger winds, expect near
critical fire wx values leading to higher wildfire potential,
especially given the extended dry period.

Monday night through Tuesday, The front and axis of higher moisture
will spread across Upper Michigan with PWAT values climbing near 1.4
inches. However, with the blocking ridge to the east, the stronger
supporting qvector conv and upper level div may lift more to the
northeast of the CWA. Although POPs have trended higher compared to
previous forecasts, there is still uncertainty about the coverage
and amounts, especially over the central and east.

Wednesday and Thursday, Additional pcpn may be possible as another
shortwave trough moves out of the plains. However, there is even
greater uncertainty with the position and timing of this feature.

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 142 PM EDT FRI MAY 20 2016

With dry hi pres dominating the Upper Great Lakes region, expect VFR
conditions and light winds at all the TAF sites through tonight.
Just some high based cu is expected this afternoon. Weak trough
moves across on Sat which will switch winds to NW-N. Winds should
stay less than 10 knots and conditions will remain VFR.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 320 PM EDT FRI MAY 20 2016

A quiet late spring pattern is expected for Lake Superior for this
forecast period with high pressure over the Great Lakes region.
Winds will be mostly under 15kt each day. Winds on Monday will
increase to 20 to 25 knots ahead of a trough lifting through the
Northern Plains and this will be the strongest winds expected in
this forecast.

Upper Michigan...
  Fire Weather Watch from Monday morning through Monday evening
     for MIZ001>015-084-085.

Lake Superior...
Lake Michigan...


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