Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KMQT 212007

Area Forecast Discussion
National Weather Service Marquette MI
407 PM EDT SAT MAY 21 2016

.SHORT TERM...(This evening through Sunday)
Issued at 339 PM EDT SAT MAY 21 2016

A decaying sfc trough sagging southward across Upper MI this
afternoon is creating enhanced convergence across the south half of
the CWA. A few radar echoes are surpassing 30dBz as low as 3kft, so
even though the sfc layer is very dry, a few sprinkles may reach the
ground through this evening.

Upper ridging building across the Upper MS Valley and sfc ridging
drifting eastward across Upper MI will bring clear skies with a few
passing high clouds and afternoon inland cumulus through Sunday.
H8/H9 temps a degree or two Celsius higher on Sunday will favor sfc
temps in the upper 70s to low 80 away from the immediate shores,
where widespread lake breeze development is expected.

The light winds will limit daytime boundary layer mixing to some
extent, but min RH values will still fall well into the 20s inland.
Some upper 10s cannot be ruled out across the interior east where
dry NE flow tonight ahead of the surface ridge leaves behind very
dry low-levels. Overall, with winds remaining light away from any
lake breeze boundary, Sunday will be another day of drying ahead of
the expected increased fire potential on Monday.

.LONG TERM...(Sunday night through Saturday)
Issued at 355 PM EDT SAT MAY 21 2016

...Critial fire weather conditions still possible for Monday...

The persistent dry weather pattern should come to an end this week.
How much rain is still a question though. The May 2016 precip thus
far of 0.45 inches at the NWS office near Negaunee ranks as 9th
driest since records began in 1961. In the shorter term, last time
the daily precip was over 0.10 inch was on May 12th. This stretch of
dry weather coinciding with spring green up is resulting in elevated
wildfire potential. Thus far, the warm and dry period have not been
combined with strong or gusty winds, but that does change on Monday.

Sunday night into Monday is the main concern for elevated wildfire
potential due to poor relative humidity recovery on Sun night and
gusty south winds on Monday. Lowest min RH will be over central and
east, while the strongest winds will occur over the west half. Based
on recent fuel indices from the Great Lakes Fires and Fuels page the
central U.P. seems to be where lowest RH and strong/gusty winds sync
up with where indices are worst. That said, all of Upper Michigan
will see elevated wildfire potential and so no reason to alter
going fire weather watch.

Once the front moves through Monday night into Tuesday, at the least
should see increase in low-level moisture as dwpnts move into the
50s. The increase in moisture will bring better chances of rain as
the front stalls out Tuesday into Wednesday. Still looking for an
elusive widespread wetting rainfall. Depending on how close the
front is when it stalls, could see some widespread showers as
another low pressure waves lifts along the front. Models indicate
maybe a more likely scenario initially would be scattered showers
and isolated thunderstorms developing on Tuesday as front is
overhead and with additional convergence from lake breezes. Sfc
dwpnts into the 50s along the front would support sfc based cape
values to around 500j/kg with potential for up to 1000j/kg if dwpnts
push more toward 60 degrees. Supercell composites taking into
account effective shear and instabilty fm GFS and ECMWF point to
best chance of organized storms over interior west half. Front sags
farther south Tuesday night into Wednesday. WSW flow aloft suggests
shortwaves could ride along the boundary into late in the week, but
there is disagreement on extent of instability and thus coverage of
shra/tsra. Kept the consensus pops in there and retained small
chance of tsra through the period. At this point, severe weather is
not expected.

Only other issue in the long term beyond Tuesday is potential for
fog on Lk Superior as the higher dwpnts spread over mainly the open
waters with sfc temps 38-42F. Coverage of fog will depend on extent
of rain that falls over Lk Superior Monday night into Tuesday. More
rain would lead to greater low-level moistening and cooling and
better chance of fog. Went with patchy coverage for now. Onshore
flow late Tuesday night into Wednesday could allow for a little fog
near Lk Superior shore. &&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 142 PM EDT SAT MAY 21 2016

Other than some passing mid-level clouds, expect clear conditions
through the period. Generally northerly winds this afternoon will
become light tonight before becoming southerly late Sunday morning.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 339 PM EDT SAT MAY 21 2016

High pressure over the Upper Great Lakes will keep winds under 15
knots through Sunday afternoon. Southerly winds of up to 25 knots
are then expected Sunday night through Monday night as a low
pressure trough approaches from the west. The trough will stall over
the Upper Great Lakes Tuesday through Thursday, bringing winds
generally under 15 knots.

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

Lake Superior...
Lake Michigan...


MARINE...Kluber is the U.S. government's official web portal to all federal, state and local government web resources and services.