829
FXUS63 KAPX 290203
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1003 PM EDT Sun Apr 28 2024

.KEY MESSAGES...

- Occasional showers and a few thunderstorms through Monday.

- Potential for a few showers mainly north and west Wednesday
  night

- Unsettled weather featuring showers and perhaps some thunder
  chances set to close out the week.

- Cooler airmass looks to intrude by the weekend.

&&

.UPDATE...
Issued at 1003 PM EDT Sun Apr 28 2024
Widespread showers continue to stream northward through our CWA
late this evening ahead of low pressure slowly lifting out of
Iowa and into the Western Great Lakes region. Steady feed of
deep moisture surging northward ahead of the low center and
up/over the associated warm front is fueling ongoing precip
production. Latest near term models still show very weak
instability thru the night...so still cannot rule out a rumble
or two of thunder. Current forecast is handling this scenario
well...no major changes needed for the balance of the night.
Temps will generally hold in the 40s overnight.

&&

.SHORT TERM /THROUGH TUESDAY/...
Pattern Synopsis/Forecast: Shortwave ridging currently encompasses
the western Great Lakes region with more amplified troughing
upstream across the northern Plains and Great Plains. Ridge axis
slides east of the forecast area this evening with troughing
becoming more prevalent tonight through Monday. At the surface,
yesterday`s cold front now situated over southern and central lower
MI, effectively becoming a warm front tied to low pressure centered
near the NE/IA border early this afternoon. That warm front will
slowly move north over the next 24-36 hours as low pressure meanders
through the upper Mississippi Valley to near western Lake Superior
by 00z Tuesday.

Forecast Details:

Occasional showers/storms through Monday: A few waves of scattered
to numerous showers are anticipated this afternoon (already
ongoing) through tonight as warm, moist advection/isentropic
ascent continue to spread across northern Michigan. Suppose a
few rumbles of thunder not entirely out of the question later
this afternoon into tonight given fumes of elevated instability.
Those shower chances progged to continue Monday -- most
numerously early Monday morning. Isolated to scattered
thunderstorms possible Monday afternoon in advance of a cold
front tied to aforementioned low pressure passing to our
northwest. While stronger storms aren`t necessarily expected,
it`ll be worth monitoring instability trends for Monday
afternoon given pre-frontal effective bulk shear progged around
35 kts.

Low temps tonight in the upper 30s far north and through the 40s for
much of northern lower. Wide range in high temps expected Monday,
largely hinging on warm frontal placement by mid-afternoon. Current
trends support highs in the low 50s over eastern upper and from the
mid-50s near the Straits and far northeast lower to the mid 60s
through low 70s near and south of M-32.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Pattern Synopsis / Forecast: 500mb low and associated broad surface
low pressure (~1005mb in the vicinity of Sioux City, IA) evident on
water vapor imagery over the northern Plains and western Corn Belt.
Attendant stationary boundary stretching east through southern
Michigan will be drawn northward with the system as the surface low
moves eastward through Lake Superior Monday, leaving us with a cold
frontal passage early Monday night that will bring about some
continuity of showers and perhaps some embedded thunder across
northern Michigan Monday night. Following the passage of the front,
cooler (but still relatively mild) air will reside overhead beneath
a well defined subsidence inversion, resulting in just some diurnal
cumulus through the day Tuesday. Next batch of showers set to
intrude into the region Tuesday night into Wednesday as a wave
ejects from the northern Rockies and rides zonal flow enhanced by
disheveled longwave troughing over the Canadian prairies. Zonal flow
continues as the front becomes stationary over Michigan before
another wave ejects into the central Plains, with surface low
potentially deepening considerably before lifting through the upper
Midwest into Canada, bringing another shot at some showers and
perhaps some thunder toward the weekend, and the return of cooler
air.

Primary Forecast Concerns:

Rain should trend less widespread through the overnight hours on
Monday as the surface low clears Lake Superior and synoptic
subsidence intrudes into the Great Lakes. Overall, not a lot of
additional rainfall Monday night as the bulk of the forcing and
energy departs to the east, marked by some lingering showers
/ thunder near Saginaw Bay in the evening (CAMs still have some
meager surface instability on the order of ~500 J/kg thru 03z
Tuesday), and some showers right along the passing surface cold
frontal boundary that should be moving into Lake Huron by 09z
Tuesday. Expecting drier weather to build rather quickly from west
to east, with perhaps just some lingering showers around the Soo by
sunrise. It will be replaced by drier weather for Tuesday, with
partly sunny skies amid a westerly flow with temps in the 50s across
the eastern UP and Lake Michigan shores, with 60s elsewhere
(possibly near 70 closer to Saginaw Bay?).

Next shower chances will be late Tuesday night into Wednesday as a
quick moving wave races northeast through Minnesota. Given origins
from the northern Rockies, not a ton of moisture to work with this
one. This feature will slingshot a warm front into the region, while
surface low pressure occludes over western Lake Superior and lifts
northward. Result will be limited shower coverage the farther south
and east one goes across the CWA, with better shower chances north
and west (as stated by previous forecaster). Flow associated with
this front looks to be parallel, which may lead to the front
becoming more stationary overhead. This may open the door for more
unsettled weather to close out the week before the bigger Plains low
develops and forces the pesky stationary boundary out of the Great
Lakes as a cold front passes closer to the weekend. Will have to
watch how much cooler the resulting airmass is for frost/freeze
potential considering area trees / plants may be reaching critical
points in growth stages.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Low pressure currently centered over Iowa will slowly lift NE
into and thru Lower Michigan tonight and Monday. Deep moisture
surging northward ahead of this system will continue to produce
widespread showers and a few thunderstorms across all of Eastern
Upper and Northern Lower Michigan thru Monday evening.
Conditions will drop to IFR as widespread showers develop
tonight and Monday. Surface winds will be mainly from the E/NE
at 15 to 25 kts.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 11 PM EDT Monday for LHZ345>348.
     Small Craft Advisory until 5 PM EDT Monday for LMZ323-341-342.
     Small Craft Advisory from 5 AM to 8 PM EDT Monday for LSZ321-
     322.

&&

$$

UPDATE...MLR
SHORT TERM...MJG
LONG TERM...HAD
AVIATION...MLR