Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 182345

Area Forecast Discussion
National Weather Service Marquette MI
745 PM EDT WED MAY 18 2016

.SHORT TERM...(This evening through Thursday)
Issued at 351 PM EDT WED MAY 18 2016

High pressure at all levels will continue to dominate the western
Great Lakes maintaining dry conditions through Thursday.

Again favored the lower side of temp guidance tonight under clear
skies and PWAT values at or blo 0.5 inch, particularly over
traditional interior cold spots which will likely fall at or
slightly below the freezing mark. Locations closer to the Great
Lakes will generally be in the mid to upper 30s.

Models show a developing sfc trough on Thursday enhanced by lake
breeze circulations. This trough will be the focus for some high-
based cu by Thu afternoon over mainly the interior west half of
Upper Mi. Mixing slightly above 800 mb per forecast soundings under
mostly sunny skies will allow for inland highs on Thu to reach into
the upper 60s to lower 70s...warmest over the interior west.
Diurnal mixing of drier air to sfc will also lower dew points into
the upper 20s to lower 30s...again yielding RH values mainly in the
20 to 25 percent range over most interior locations. Used a blend of
the local mixed dewpoint tool along with bias corrected Canadian
model guidance to produce dewpoints. Once again winds are expected
to be light which should aid in limiting fire weather concerns
despite very dry conditions.

.LONG TERM...(Thursday night through Wednesday)
Issued at 408 PM EDT WED MAY 18 2016

Quiet pattern until further notice in terms of day to day weather as
upper ridge and sfc ridge dominate over the Upper Great Lakes in
some shape or form. Thus far the 2016 May 1st-17th period is in the
top 10 for driest on record. Only will extend the dryness through
the upcoming weekend. Fire weather quickly becoming issue as green
up remains slow in larger scale fuels such as pine trees over much
of Upper Michigan.

Sfc high in the vcnty through rest of week leads to persistent
weather pattern. Dry is the way to go. Used bias corrected Canadian
guidance for min temps and leaned that way for aftn dwpnts/RH. Since
the sfc high center will be southeast of cwa over lower Michigan to
the lower Great Lakes, primary lake breeze Fri will be off Lk
Michigan. Increased SSE-S winds over northern Lk Michigan/Bay of
Green Bay and over adjacent land areas of south central U.P. Temps
Fri into Sun gradually warm with maxes reaching toward 80 degrees
by Sun. Min RH values look to bottom out at 20-25 percent each day.
Away from the lake breezes winds should be relatively light. Given
the long stretch of dry and warm weather though, any day with gusty
winds could quickly cause fire weather issues.

Seems like models are latching on to Mon as being a day that fire
weather could pushing near critical thresholds. Shortwave trough
lifts across northern plains-scntrl Canada with sfc low and trough
trying to push toward Upper Great Lakes. Pressure gradient tightens
as the trough will be pushing into slowly departing ridge. S-SW
winds increase to 15-18 mph with gusts up to 25 mph, strongest west
half. H85 winds fm GFS/ECMWF are 30-40 kts, so if there is full
sunshine and deep mixing gusts could be on the strong side which
would only accentuate fire weather issues.

Trough eases over Upper Great Lakes Mon night into Tue. Stongest
larger scale forcing lifts northwest of Upper Michigan, but the low-
level trough along with theta-e ridging and at least some elevated
instability may support shra/tsra making it over cwa. Better chance
would be if the trough stalls out over cwa on Tue and another
shortwave lifts along the trough. Dry airmass and lack of large scale
forcing argues against anything more than small chance pops.
Widespread wetting rain which is needed now but certainly will be
needed by early next week does not look likely until maybe just
beyond the scope of this 7 day forecast.

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 745 PM EDT WED MAY 18 2016

With dry high pressure dominating the Upper Great Lakes region,
expect VFR conditions and light winds at all the TAF sites. Expect
some mid-level clouds developing Thursday afternoon.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 351 PM EDT WED MAY 18 2016

A quiet late spring pattern is expected for Lake Superior for the
remainder of this week as high pressure settles over the Great Lakes
region. Winds will be mostly under 15kt each day. Winds on Monday
may increase to 20 knots ahead of a trough lifting through the
Northern Plains.

Upper Michigan...
Lake Superior...
Lake Michigan...


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