Area Forecast Discussion Issued by NWS Marquette, MI
000
FXUS63 KMQT 121953
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
353 PM EDT Fri Apr 12 2024
.KEY MESSAGES...
- Deep low pressure over Quebec continues gusty north to
northwest winds up to 30-40 mph, stronger winds are expected
over the eastern UP.
- Periods of showers into next week, including Saturday night
and then through much of next week.
- Temperatures on most days will be above normal through the
first half of next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 352 PM EDT Fri Apr 12 2024
Current RAP analysis shows the strong low pressure system northeast
of Lake Huron over the Ontario/Quebec province line with weak sfc
high pressure along the Dakotas/Minnesota state lines. The mid level
trough is located just southwest of sfc low and is centered over
Lake Huron/southern Ontario. A broad mid level ridge is analyzed
over the Rockies/Plains with a closed low off the western U.S.
coast. With the sfc low and mid level trough no longer vertically
stacked well, the sfc low will weaken into tonight as it lifts north
through Quebec while the trough progresses east-northeast into
Quebec/New England. Lingering light rain showers over the far
eastern UP will diminish from west to east into this evening as the
sfc low departs. No major accumulations beyond 0.01" are expected.
This set up continues a tighter pressure gradient over the UP into
tonight resulting in some gusty northwest winds, especially over the
east. Gusts around 20 to 30 mph are expected over the western third
of the UP with the remainder of Upper Michigan gusting up to around
30 to 40 mph; some gusts along the eastern lakeshores could reach 45
mph yet this afternoon. Thus, the wind advisory will continue
through 8 PM EST this evening for Alger/Delta counties eastward.
While the northwest winds off Lake Superior have kept the eastern
lakeshores cooler in the low to mid 40s, temps elsewhere have warmed
up into the mid 40s to mid 50s with the warmest over the south
central UP; not much if any additional warming is expected today.
Tonight, sfc high pressure will gradually build in from the west and
the pressure gradient overhead will slacken. PWATs show a 0.1" drop
across the UP as drier air moves in from the northwest, something
already noted in the water vapor imagery over Minnesota. The drier
air will help clear skies out as northwest winds weaken; gusts drop
back down to around 20 to 30 mph by Saturday morning with strongest
winds located near the eastern lakeshores. Clearer skies will also
help bring lows down into the upper 20s to mid 30s, warmer near the
lakeshores.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 520 AM EDT Fri Apr 12 2024
An active period is on tap through next week, resulting in frequent
opportunities of rainfall. After the storm now moving through the
Lower Great Lakes lifts north through Quebec later tonight, a
temporary quasi-zonal sets up across the area Saturday into Monday
as a shortwave tracking along the MN/Canadian border could spread
some scattered showers into the mainly northwest and eastern
sections of the U.P. Saturday night/early Sunday. After a dry and
seasonably mild day on Sunday, the zonal flow across the
U.S./Canadian border breaks down early next week as a
shortwave/closed low drops out of the Gulf of AK into the western
CONUS and in turn kicks a shortwave out of the Southwest U.S lifting
it through the Plains and into the Great Lakes by the middle of next
week. The developing low will bring widespread shra into Upper MI
Tuesday into Wednesday. One or maybe two more low pres waves may
lift through the Great Lakes late next week as western mid-level
troughing progresses downstream, providing additional opportunities
of pcpn. Above normal temps through much of the period will trend
slightly blo normal late next week into next weekend with the
progression of the western troughing and the passage of an
associated cold front through the area.
This weekend, weak ridging moves slowly west to east across the area
on Saturday should result in dry conditions through much of the day.
A shortwave tracking e along the vicinity of the MN/Canadian Border
will spread waa/isentropic ascent toward Upper MI by evening.
Combined with an advancing sharp 850mb theta-e gradient and vigorous
upper diffluence from the right entrance region of a 100kt upper jet
streak extending from northern Lake Superior into the Lower Great
Lakes, scattered showers should spread into w/nw Upper MI late
afternoon/early evening Sat. Scattered showers will then streak
across the fcst area Sat night, ending by sunrise Sunday. Pool of
elevated instability of 100-400 j/kg builds toward Upper MI for Sat
night, and it may be just sufficient toward the MI/WI stateline for
a rumble or two of thunder. Following the showers on Sat night,
Sunday looks to be a nice mid-Apr day under increasing sunshine.
Highs Sat will be in lower 60s over the interior west half and
mostly in the lower to mid 50s elsewhere. Highs Sun will be well
into the 60s F across the interior w half and south central and
mostly in the mid to upper 50s elsewhere.
By Monday, the quasi-zonal flow in the vicinity of the U.S./Canada
border will be breaking down as a shortwave drops out of the Gulf of
AK into the nw U.S. Downstream, upper jet will be forced to lift n,
again placing right entrance region upper diffluence over the area.
There are also hints of a weak shortwave tracking toward Upper MI.
So, a mention of pcpn is warranted at least across the w, but still
only 20-30pct chc for now. Continued ridging over the area should
keep conditions mostly dry across the area Mon night into Tue
morning.
Attention then turns to the wave over the Southwest U.S. that gets
kicked ne by the shortwave dropping from Gulf of AK through the NW
U.S. Surface response will be a deep sfc low organizing in the lee
of the Colorado Rockies. This low will reach peak strength over the
Plains on Tuesday, and then weaken as it lifts ne into the Upper
Great Lakes and northern Ontario/Quebec Tue night into Wed. With a
good surge of Gulf moisture ahead of the approaching low (layer
precipitable water values increase to over an inch or 225-250pct of
normal), expect widespread showers, maybe some thunder, to develop
late Tue into Wed. However, given the high pwats ensemble
probability guidance is not very bullish on total rainfall from this
system, probably since the system and associated dynamics are
weakening as it moves across the area. Ensembles suggest a 60-80 pct
probability of a half inch or more of rainfall over south central
portions with less than 50 pct chance of a half inch across the rest
of the fcst area. Breezy conditions will develop well Tue into Wed.
Models suggest showers may taper off a bit late Wed into Wed night
behind the low as it lifts to the ne. However, additional shortwaves
ahead of and with the passage of the approaching western CONUS trof
and associated closed low could reinvigorate showers Thu into Fri.
Temps will begin to trend blo normal in the wake of Thu`s cold
frontal passage.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 157 PM EDT Fri Apr 12 2024
Lingering MVFR cigs at IWD will return to VFR this afternoon as
light rain showers end within the next hour. Otherwise VFR
conditions will prevail the remainder of the 18Z TAF period as a
strong low pressure system just northeast of Lake Huron lifts north
into Quebec. The tight pressure gradient across the UP is yielding
some gusty northwest winds up to 25 kts at IWD and 35 kts at SAW and
CMX this afternoon. As the low departs and high pressure builds in
from the west, winds will weaken overnight into Saturday. Some low
level wind shear is possible at SAW tonight, however was left out of
the TAF for now as confidence remains low. Dry northwest flow will
also work to clear skies overnight.
&&
.MARINE...
Issued at 520 AM EDT Fri Apr 12 2024
Deepening low pres will lift into southern Ontario and to near
Georgian Bay this morning. In response, N to NNW winds will ramp up
today, reaching 40-45kt gales over the east half of Lake Superior
today. Internal probabilistic guidance indicates a 20pct chc of peak
gusts reaching storm force over the far se part of the lake btwn
Grand Marais and Whitefish Pt. As the low pulls away and high pres
ridge arrives on Sat, winds will diminish to blo gale force late
tonight/early Sat and to 20kt or less by Sat afternoon. Winds will
then remain mostly under 20kt thru Sun. Another deep low will begin
to organize on the lee side of the Rockies late on Mon. Easterly
winds will begin to increase late Mon night to 25-30kt, highest over
the western third of the lake. Ensemble guidance indicates a 70 to
near 100 pct chc of easterly gales of 35-40kt Tue aftn into Tue
night across much of Lake Superior. The gales may linger into Wed
morning before diminishing.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Wind Advisory until 8 PM EDT this evening for MIZ006-007-013-
014-085.
Lake Superior...
Small Craft Advisory until 5 PM EDT /4 PM CDT/ this afternoon
for LSZ241>243.
Gale Warning until 5 PM EDT this afternoon for LSZ244-264.
Small Craft Advisory until 8 AM EDT Saturday for LSZ244.
Gale Warning until 7 PM EDT this evening for LSZ245-248-265.
Small Craft Advisory from 7 PM this evening to 8 AM EDT
Saturday for LSZ245-248.
Small Craft Advisory until 11 PM EDT this evening for LSZ246-
247.
Gale Warning until 2 AM EDT Saturday for LSZ249-250-266.
Small Craft Advisory from 2 AM to 2 PM EDT Saturday for LSZ249-
250.
Gale Warning until 8 AM EDT Saturday for LSZ251-267.
Lake Michigan...
Gale Warning until 8 PM EDT this evening for LMZ221-248-250.
&&
$$
SHORT TERM...Jablonski
LONG TERM...Voss
AVIATION...Jablonski
MARINE...Voss