848
FXUS63 KAPX 161950
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
350 PM EDT Mon Jun 16 2025

.KEY MESSAGES...

- Showers tonight...spotty at first but increasing chances overnight.

- Shower/thunderstorm chances Tuesday...possible stronger storms.

- Heavy rainfall threat Wednesday?

- First significant heat of the summer early next week?

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 347 PM EDT Mon Jun 16 2025

Pattern Synopsis/Forecast: Large scale pattern features broadly
zonal flow across the northern tier of states...downstream of a
trough axis off the west coast.  Broad ridge over the southwestern
U.S./southern Plains with an elongated trough axis moving into the
lower Mississippi Valley.  A couple of short wave troughs within the
northern tier zonal flow...one crossing Lower Michigan this
afternoon showing up nicely in water vapor imagery...a second better
defined wave (and perhaps convectively enhanced) over the Dakotas/
Nebraska.  Also a remnant MCV over southeast Wisconsin.  Visible
imagery also hints at a southeastward propagating gravity wave over
northern Ontario and extending back into northern Lower.  There is a
fair bit of humidity working its way back into the upper Great Lakes
this afternoon.  At the surface...ridge of high pressure extends
west from New England into the Great Lakes...with a weakly organized
area of low pressure over the northern Plains/upper Midwest.  Small
stub of a warm front lies across South Dakota/Iowa...with a poorly
defined boundary along the Ohio River.  Farther to the north an east-
west oriented front runs across far northern Ontario into Manitoba.

Northern Plains short wave trough is forecast to cross Lake
Superior/Upper Michigan during the first half of Tuesday...along
with a compact surface reflection (already 2-3mb/3h pressure falls
across the eastern Dakotas coincident with a 1006mb low center).
While the surface low is expected to propagate away from Lake
Superior...it will drag a weakening cold front across Michigan
Tuesday afternoon.

Primary Forecast Concerns:

Showers late afternoon/early evening: Passing gravity wave front
kicked off some scattered showers as is passed through fairly
quickly during the late morning/early afternoon across eastern Upper
and the Straits region.   Cu field has been bubbling up across
northwest Lower...instability as expected is pretty thin at just a
few hundred J/kg.  So remains to be seen whether short wave trough
emerging out over Lake Michigan can kick off any showers...or will
subsidence behind gravity wave squash any minimal potential (as
would be suggested by mid cloud clearing in its wake).  But moisture
will continue to increase from the west this evening ahead of the
approaching surface low that is expected to be over central Lake
Superior by Tuesday morning with its trailing cold front back across
eastern Wisconsin. Would expect remnants of convection over the
upper Mississippi Valley this afternoon to get pushed into northern
Michigan overnight...in addition to any scattered convection that
develops ahead of it along advancing moisture axis.

Shower/thunderstorm chances Tuesday...possible stronger storms:
Would expect rain to be ongoing Tuesday morning especially east
of the US-131 corridor. Cold front arrives during the afternoon
and with it a decent axis of instability (likely > 1000J/kg
MLCAPE). If this comes to fruition could be some sneaky stronger
storms with the front and will mention this possibility in the
afternoon Hazardous Weather Outlook despite only being in the
General SPC Day 2 outlook.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 347 PM EDT Mon Jun 16 2025

Days 2-3 (Wednesday-Thursday): Tuesday`s cold front looks like it
will stall across southern Michigan...along which a frontal wave
will ripple northeast and across Lower Michigan probably Wednesday
night.  Exactly how the surface pattern will evolve is a bit unknown
as model latent heat release is likely playing around with the model
surface pressure pattern.  But a good bit of moisture in play along
and north of this front...along with potentially favorable jet
dynamics is setting up the possibility for heavy rainfall across the
forecast area for Wednesday and especially Wednesday night. Rainfall
amounts of 1-2+ inches could be in play for some areas depending on
how the details set up.  But something else to add to the afternoon
HWO (most of Michigan in the Marginal WPC Day 3 Excessive Rainfall
Outlook).

Days 4-5 (Friday-Saturday):  Drying trend for Friday as 594+DM 500mb
ridge expands eastward across the Mississippi Valley and into the
southeastern U.S..  Northward moving frontal boundary associated
with this warmer air mass expected to push across the upper Lakes
Saturday and will likely bring another round of showers/
thunderstorms with it.

Days 6-7 Outlook (Sunday-Monday): CPC 6-10 Day outlook looking
pretty toasty as 594DM heights build into northern Michigan (a +2 to
+3 sigma 500mb standardized height anomaly).  As long as we are far
enough south of potential MCS "ridge runners" which is always our
bugaboo for much hyped heat events...the first round of 90+ degree
heat is certainly in play heading into next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 150 PM EDT Mon Jun 16 2025

KTVC will likely see a lake breeze development this afternoon
resulting in winds quickly steering to the north before flow
turns southeast tonight. Some instability develops late
overnight across the region, resulting in some gusty winds with
chances of showers Tuesday morning. Most areas likely remain
VFR, but low level cloud development this Tuesday along with a
few chances of thunder development could lower CIGs to MVFR
conditions, especially near KCIU.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

SHORT TERM...JPB
LONG TERM...JPB
AVIATION...SJC