Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 261915

Area Forecast Discussion
National Weather Service Marquette MI
315 PM EDT THU MAY 26 2016

.SHORT TERM...(Today and tonight)
Issued at 444 AM EDT THU MAY 26 2016

A couple (more) shortwaves will bring convection to the area this
afternoon/evening and then moving in late tonight.

Early morning rain will continue to exit the area over the next few
hours and fog will dissipate this morning over land.

Big question for today is the extent/coverage/intensity of
afternoon/evening convection as the shortwave (currently over NE)
moves through. Most models show some convection over the area today,
but models that show the least intense convection do not adequately
show the line of convection over IA and SE MN, so leaned more on
models that are better representing that. Good timing of the
shortwave to intercept peak heating. Have max temps up to 80 F over
the interior north central and west, and up to the mid 80s near the
WI border. Reasonable expectation for MLCAPEs today are around 1,500
J/kg, although the NAM has over 2,500 J/kg (appears to be too moist,
which is a known bias) and the GFS has just over 1,000 J/kg. The
1,500 J/kg was based on adjusted NAM soundings, the SREF mean and
UCAR ensemble. Low level winds will be on the light side, but with
40-45 kt westerlies, 0-6 km effective shear will be 40-50 kts.
Hodographs are favorably oriented for storm organization in a hockey
stick shape. With lake breezes developing today, most concern is
over the central (mainly north central) where E moving storms may
become pinned to the lake breeze boundary and become right deviant
as they follow the boundary to the SE. If this occurs, any right
movers will see enhanced inflow and shear, and could produce a
tornado or two. Confidence in the tornado threat is very limited and
the circumstances are quite conditional, but it can`t be ruled out.
Isolated large hail and damaging wind threat is a greater potential.
Will include wind/hail threat in the HWO/EHWO, lower confidence of
tornado threat will exclude that from being mentioned.

Additional, non-severe convection will approach or move into areas
near the WI border late tonight as another shortwave approaches.

.LONG TERM...(Friday night through Thursday)
Issued at 314 PM EDT THU MAY 26 2016

Upper air pattern forecasted to be a trough in the Pacific NW and
another trough in the central plains 00z Sat. There is also a broad
500 mb ridge over the ern U.S. 00z Sat that builds into the upper
Great Lakes region Fri night. This trough moves east into the Upper
Great Lakes Sat night into Sun.

Continues to look unsettled this forecast period through Sun and
hard to pin down any details with the numerous shortwaves moving
through. Will not be a total washout as there could be some brief
dry periods mixed in there from Fri night into Sun, but timing these
is next to impossible with convection that has not even developed
yet. Easiest course is to go with persistence and broadbrush this
forecast. Overall, did not make too many changes to the going
forecast for temperatures or weather.

In the extended, GFS and ECMWF show two broad 500 MB troughs across
the western and eastern U.S. 12z Mon. The trough over the western
U.S. moves into the Rockies 12z Tue and into the northern plains 12z
Wed which remains into 12z Thu. Still looks unsettled and
temperatures look to be near normal to slightly above normal for
this forecast period.

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 218 PM EDT THU MAY 26 2016

Rain showers and isolated thunderstorms will affect the TAF sites
this afternoon. Best chance of prevailing thunder will be at KSAW.
Distubance causing rain lifts out of area this evening. With enough
clearing could see low clouds and fog at all the TAF sites overnight
tonight into Friday morning. Conditions could drop to VLIFR,
especially at CMX as winds due to closer proximity of the widespread
fog on Lk Superior. More showers and thunderstorms should roll back
in late Friday morning or into Friday afternoon.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 444 AM EDT THU MAY 26 2016

Expect winds at or below 20 knots through the forecast period. Fog
will continue to be a problem at times and will be dependent on the
rain that falls.

Upper Michigan...
Lake Superior...
  Dense Fog Advisory until 6 PM EDT /5 PM CDT/ Friday for LSZ162-

Lake Michigan...
  Dense Fog Advisory until 10 AM EDT Friday for LMZ248-250.



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