Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 181954

Area Forecast Discussion
National Weather Service Marquette MI
354 PM EDT Fri May 18 2018

.SHORT TERM...(This evening through Saturday)
Issued at 354 PM EDT FRI MAY 18 2018

WV imagery and RAP analysis indicated a ridge from NY/PA into the
northern Great Lakes and a troughs from Manitoba into the nrn Plains
and from ern Missouri into Alabama. At the surface, moderate south
to southeast winds of 10-15 mph gusting to 20-25 mph prevailed
across Upper Michigan between high pressure over Quebec and an
inverted trough into nw MN. Dewpoints in the 25-30F range with temps
from the 60s east to 70s west have dropped RH values into the 20-25
percent range over much of the area. The breezy, warm dry conditions
have resulted in an elevated wildfire risk. Since winds are expected
to remain below Red Flag criteria, an SPS was reissued to highlight
the risk into this evening.

Tonight into early Saturday, models have trended signficantly
farther west with a shortwave trough lifting to the nne from IL. As
a rresult, rain chances have increased over the southeast half of
Upper Michigan from late tonight into Saturday morning. However,
rainfall amounts should remain light, at or below a tenth of an
inch. Temps dropping into the 40s along with some additional low
level moisture, will aid RH recovery into the 70-80 pct range.

The Manitoba/nrn plains shrtwv will slide to the east dragging a
cold front through Upper Michigan. Although the 700-300 qvector conv
and fgen with this feature is relatively modest, it should still be
able to generate sct -shra advancing through the west half of Upper
Michigan by late afternoon into the evening. Again, any rainfall
amounts will be light. Temperatures will drop substantially by mid
to late afternoon into the 40s over the north as onshore nrly winds
develop off of Lake Superior.

.LONG TERM...(Saturday night through Friday)
Issued at 320 PM EDT FRI MAY 18 2018

The main forecast concern in the extended will be the elevated fire
weather potential for much of next week as little to no rain
is expected.

Beginning Sat night, there could be an isolated shower along/behind
exiting trough/cold front mainly over the se portion of the fcst
area. Otherwise, expect decreasing clouds from the north and west
late Sat night.

Much of next week will be dry as models maintain split flow pattern
across the western half of the CONUS and a confluent nw flow into
the Upper Great Lakes region. Although winds will remain fairly
light across the area under persistent sfc high pressure, daytime
minimum RHs will continue to be fairly low (20-30% range) through
much of the week, heightening fire weather concerns in this
persistent dry pattern. Unfortunately, the next best chance of
rainfall looks like it won`t be until late next week (at the
earliest) as a shortwave trough moves in from the Northern Plains.
At this point, there`s plenty of model uncertainty on the strength
of this wave and whether there will enough available moisture to
produce any meaningful rainfall. A few of the recent model runs
suggest a shortwave from the Plains could bring some light rain into
the southeast fcst area on Monday, but again even if this happens,
it will do little to quell fire weather concerns over the next week.

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 136 PM EDT FRI MAY 18 2018

VFR conditions with scattered mid and high level clouds will prevail
at all TAF sites through tonight. Gusty south to southeast winds
this afternoon, strongestt SAW will become lighter tonight, but more
LLWS will return to CMX as a southerly low level jet develops above
the low level inversion out ahead of an approaching front. MVFR cigs
are expected to move into western Upper Michigan at KIWD and to near
KCMX by late Saturday morning as a cold front moves through the area.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 354 PM EDT FRI MAY 18 2018

Southeast winds of 15 to 25 knots will persist over eastern Lk
Superior tonight, before diminishing late. Winds will be less than
20 kts to start day on Sat but will shift north 20 to 30 kts in the
aftn and evening behind a front dropping across Lk Superior. Winds
will diminish to less than 20 kts late Sat night through the rest of
the forecast period as high pressure parks itself over the Upper
Great Lakes.

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


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