526
FXUS63 KAPX 200733
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
333 AM EDT Fri Sep 20 2024

.KEY MESSAGES...

- Rain/thunder chances return today

- Chances for widespread rain and isolated thunder Sunday

- Cool down next work week&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 333 AM EDT Fri Sep 20 2024

Pattern/synopsis: An upstream cold front has pushed into western
WI and eastern IA. Decaying pre-frontal convection extends from
the WI/IL border up thru central Lk Superior. The front is
progged to slow as it crosses eastern WI today, and then moves
into northern MI tonight.

Forecast: Cloud cover has increased in nw lower MI, and will
become somewhat more extensive as the morning proceeds. However,
that cloud cover will also thin with time. Some showers will
likely reach the nw lower MI coast, and western Chip/Mack Cos
this morning. But otherwise, this initial push of precip will
struggle in our initially dry air. Diurnal instability then
starts to kick in, and by midday convection will start to
regenerate locally. MlCape values of 600-800j/kg can be
achieved. Those higher pops will start in western areas at
midday, expanding toward and east of I-75 thru the afternoon and
into early evening. 0-6km bulk shear reaches of 30-40kt in
southern areas, where instability should also be on the higher
side. This is into a parameter space where a few strong storms
are possible. Maybe even a stray severe? But probably not. (SPC
did push the marginal svr risk northward to about GRR, but not
this far north.)

500mb trof axis pushes across the area tonight, with mid-level
subsidence/drying/warming pushing into western areas. Chance for
showers and a few storms will still be present in central and
especially eastern areas this evening. By overnight, pops linger
only in the far north and east. Without a significant push of
cooler/drier air down low, partial clearing will lead us prone
to seeing fog late, especially in the west (and perhaps near Lk
Huron).

Max temps today mostly in the 70s, perhaps hitting 80f near
Saginaw Bay. Lows tonight mid 50s to near 60f.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 333 AM EDT Fri Sep 20 2024

Saturday, skies will clear through the morning hours and lead to a
mostly sunny and warm afternoon. Clouds will begin to build back in
Saturday evening/night as the next system approaches the state.

An upper level trough over central south Canada will close and start
to tilt negatively Sunday. This upper level jet will meet with a SW
upper jet over MN/WI, and aid in moisture advection northward
towards the Great Lakes Region (PWATs ~1.4 by Sunday afternoon over
northern MI). A deeper cold front will move through the state
Sunday, as some shallow upper waves move up from the south. All in
all, there should be enough larger scale forcing present for
scattered to even widespread wetting rain Sunday. At this time, weak
instability is present in the mid to lower part of the column,
meaning it will be harder for storms to grow. It will likely be
widespread light to moderate rains with a handful of embedded low
topped cells producing some lightning. Higher uncertainty in actual
moisture amounts play into this as well, if there is a little more
dry air to work with then gusty winds could be seen with some of
that embedded convection. GFS/high res Canadian show saturation
through much of the column (after top down moistening), with the NAM
hinting at some drier air.

After the ~1015mb air mass moves through, temperatures will start to
decrease. Forecasted high temps remain in the mid to high 60s Monday
through the end of next week. Winds will be breezy at times, with
chances for rain here and there. Low confidence in details for after
Sunday rain chances due to chaotic pattern.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1128 PM EDT Thu Sep 19 2024

Looking at some patchy MVFR to even IFR producing fog/mist
impacting KAPN early this morning. Otherwise, increasing high
clouds expected to give way to a lowering cloud deck today...although
trends continue to support cigs remaining VFR. Weak front
working into the area will likely kick off some scattered
showers and a few embedded thunderstorms...spreading from west
to east through the day. Not expecting any widespread
significant impacts from these, although suppose any
thunderstorms may bring some brief gusty winds and pockets of
heavy rain. Conditions will improve from west to east later this
afternoon and evening.

&&

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

&&

$$

SHORT TERM...JZ
LONG TERM...ELD
AVIATION...MSB