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000
FXUS63 KMQT 280845
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
445 AM EDT Sun Apr 28 2024

.KEY MESSAGES...

- Much cooler today with showers lifting from south to north
  during the afternoon.
- Active pattern continues as three low pressure systems track
  across the region over the next week. Above normal
  temps/precip are expected including thunderstorm chances.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 328 AM EDT Sun Apr 28 2024

Water vapor imagery and RAP analysis show that the shortwave that
affected Upper MI yesterday is now e and ne of Lake Superior. The
next shortwave has lifted out of the southern Rockies and out over
the western Plains. This wave is supporting a long band of
convection from TX to eastern KS, then to northern IL/IN. Frontal
boundary associated with the former wave is supporting additional
convection across central Lwr MI with even a few -shra back to near
Menominee. Across Upper MI, sfc winds are in the process of veering
n to ne in response to sfc high pres building into northern Ontario
and low pres over s central KS. In this veering upslope flow, some
-dz has developed into portions of western and n central Upper MI.
This -dz may linger for another couple of hrs. Under cloudy skies,
temps at 07z mostly range thru the 40s F, but it`s still in the low
50s at Menominee, and upper 30s are becoming more common across the
w to n central.

Today will be a much cooler day than yesterday under ne winds btwn
high pres building over northern Ontario and low pres lifting to IA.
Many locations will have high temps 15-25F lwr than yesterday. Under
generally cloudy skies, expect high temps today around 40 to the mid
40s w to n central ranging up to the low/mid 50s e. As low pres
lifts to IA today, strengthening waa/isentropic ascent will spread
into the Upper Great Lakes along with a nice push of 850-700mb
moisture transport. In addition, sharpening 850mb warm front will
approach. End result will be an organizing area of shra that will
lift n out of WI into Upper MI this aftn. Consensus of recent
guidance suggests -shra should reach Menominee County early aftn and
then slowly/steadily lift n during the aftn, though there is
uncertainly in how far n pcpn will get before 00z. While no pcpn
will reach the Keweenaw thru 00z, there is uncertainty across the
rest of northern Upper MI. It`s possible areas from Ontonagon to
L`anse, Marquette and Munising/Grand Marais will remain dry thru 00z
as well, but there is sufficient support for at least a 20-50pct chc
mention in those areas 22-24z.

&&

.LONG TERM /TONIGHT THROUGH SATURDAY/...
Issued at 443 AM EDT Sun Apr 28 2024

Not much about the extended period forecast has changed with good
model agreement in three low pressure systems tracking across the
region over the next week. While this is a very active pattern with
frequent rain chances, overall weather impacts are expected to be
minor. Thunderstorm chances represent the primary hazard with gusty
winds and locally heavy rainfall representing the secondary hazards.

The first system will be on our doorstep tonight and its warm front
will be the primary mechanism focusing rain chances. There are some
noteworthy model differences with rain chances along this warm
front. Most deterministic guidance appears to focus the heaviest
rain near the nose of a 40-45 kt LLJ between 00-06z Monday. This
keeps most rainfall near the Lake MI until early Monday morning,
when the warm front surges across the area. ECMWF guidance seems to
be an outlier with a more coherent warm front passage and PoPs were
adjusted to better represent potential for two waves of rain
tonight. Steadier rain lifts northeast of the area by midday and the
cold front sweeps across the area during the afternoon, but
persistent low level cloudiness prevents much destabilization. HREF
means indicate MUCAPE values stay less than 100 J/kg until Monday
afternoon suggesting thunder/lightning will be tough to achieve
tonight, but may accompany afternoon showers. Pwats of 1-1.25
inches indicates some potential for heavy rainfall rates, but
prolonged dry conditions suggests hydro hazards are unlikely.
Rain chances end behind the cold front leading to a ~36 hour
period of dry weather ahead of the next system.

The next system approaches Tuesday evening and substantial model
differences exist. The general model consensus is for an energetic
and negatively tilted shortwave pivoting across the area Tuesday
night. The dominant surface low stays well to our northwest across
the Canadian Prairies such that the warm sector briefly tracks
across Upper MI. Most model guidance keeps the warm front dry while
focusing convection along the cold front. The nocturnal timing of
this cold front is not favorable for convection in our area, but
upper level forcing may be sufficient to compensate for that.
Ensemble means indicate a northwest to southeast precipitation
gradient with highest amounts across the far west and Copper
Country.

Model spread remains large on Wednesday, but a ~1000 mb
surface low should be in the vicinity of Lake Nipigon Wednesday
afternoon. Moderate westerly flow south of the low is expected to
result in a dry and breezy day with deep mixing. EPS peak gust
guidance shows slightly higher winds over land indicating surface
heating is important for efficiently low level mixing. At this time
westerly gusts in the 30-40 mph range are forecast across the west
half, highest on the Keweenaw where about 20% of EPS members have
peak gusts >50 mph. It should be noted that other model suites have
considerably weaker winds on Wednesday, but zonal flow south of the
surface low tends to result in deep mixing. In addition to gusty
winds, deep mixing also indicates potential for RH to dip below
currently forecast values but recent rainfall should keep fire wx
concerns in check.

Medium range guidance has trended toward another low pressure
tracking into the region to close out the work week. Rain chances
increase on Thursday as the system approaches before ending on
Friday as the system departs. Embedded thunderstorms once again
appear possible.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 126 AM EDT Sun Apr 28 2024

Medium to high confidence in IFR at IWD with persistent
upsloping early in the northerly winds behind departing low
pressure system. Confidence is low, however, in MVFR conditions
continuing at CMX and SAW through this morning, so will carry a
mention of IFR. Anticipate much fluctuation through the morning
hours though overall with increasing confidence in MVFR
becoming predominant by early afternoon. Northeasterly winds
will increase this afternoon at IWD/SAW followed by CMX this
evening, gusts in excess of 30 kts possible.

&&

.MARINE...
Issued at 443 AM EDT Sun Apr 28 2024

Generally north winds gusting between 15 and 25 knots are occurring
early this morning across Lake Superior. Winds back northeasterly
early this morning as a low pressure approaches. Northeast gales up
to 40 kt are expected across the far western lake this afternoon
with easterly gales to 40 kts spreading across the entire lake
tonight. While a few gusts may exceed 40 kts late tonight into
Monday, probabilities remain on the low end (25-50%). The strongest
winds are expected in the far west as well as the north central
portion of the lake between the Keweenaw and Isle Royale where there
could be some channeling. Gales quickly diminish Monday afternoon as
the low pressure moves over western Lake Superior.

Significant wave heights up to 14 ft are possible Monday
morning between Duluth Harbor to the Bayfield Peninsula and near
Isle Royale. Waves fall below 8 ft Monday evening.

Winds fall below 20 kts Monday night, mainly remaining below until
Wednesday morning. West winds increase to around 30 kts with a few
gale force gusts to 35 knots possible between Isle Royale and the
Keweenaw Peninsula Wednesday afternoon.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning from 2 PM EDT /1 PM CDT/ this afternoon to 5 PM
     EDT /4 PM CDT/ Monday for LSZ162.

  Small Craft Advisory until 8 PM EDT /7 PM CDT/ Monday for
     LSZ240-241.

  Small Craft Advisory until 7 PM EDT Monday for LSZ242.

  Small Craft Advisory until 11 PM EDT this evening for
     LSZ243>245.

  Gale Warning from 11 PM this evening to 5 PM EDT Monday for
     LSZ243>246-263>266.

  Small Craft Advisory from 11 AM this morning to 11 PM EDT this
     evening for LSZ246.

  Small Craft Advisory until 8 PM EDT Monday for LSZ247-248.

  Small Craft Advisory until 5 PM EDT Monday for LSZ249>251.

Lake Michigan...
  Small Craft Advisory from 6 PM this evening to 11 AM EDT
     Monday for LMZ221.

  Small Craft Advisory from 6 PM this evening to 4 PM EDT Monday
     for LMZ248-250.

&&

$$

SHORT TERM...Rolfson
LONG TERM...EK
AVIATION...TDUD
MARINE...EK