711
FXUS63 KAPX 250144
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
944 PM EDT Fri May 24 2024

.KEY MESSAGES...

- Showers and a slight chance of thunderstorms tonight.

- Rain likely Sunday night, showers continue into Memorial Day.

&&

.UPDATE...
Issued at 944 PM EDT Fri May 24 2024

Occluded low is centered along the Minnesota/Canada border late
this evening. Associated front has reached Western Wisconsin...
with the warm front extending southeastward thru Green Bay and
Lower Michigan. Area of showers and embedded sub-severe
thunderstorms continue to develop along and ahead of the cold
front...remaining mostly contained within the warm sector attm.
Latest KAPX base ref loop shows increasing shower development...
much of which is not reaching the ground as of yet thanks to dry
SE low level flow.

More substantial shower and embedded thunderstorm activity is
now moving onshore around FKS and MBL...marking the leading edge
of deeper moisture along the leading edge of the warm front.
This entire system will slide thru Michigan overnight into
Saturday morning...generating widespread showers and embedded
thunderstorms for our entire CWA. Expect thunderstorms will
remain below severe limited thanks to limited instability and
minimal shear available for organized convective development.
Overnight lows will cool into the 50s.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 314 PM EDT Fri May 24 2024

Synopsis/pattern: 994mb low pressure is over eastern ND, moving
nne. An associated occluded/cold front se and then s, across se
MN and central IA. This front crosses northern MI Saturday
morning. Aloft, shortwave energy pivots ne-ward across upper MI
and Superior late tonight.

Forecast: An initial band of showers is trying to advance across
central Lake MI. Our low and mid-levels remain pretty dry;
surface temp-dew points spreads are around 30f in some interior
areas. Perhaps a few sprinkles will be possible over the next
few hours in nw lower MI, mainly near/west of M-37. Otherwise
though, we`ll just push some thicker cloud cover into the area.

Our precip chances really ramp up from late evening onward.
Better/richer return flow develops, as sub-850mb winds become
more southerly and less easterly, just ahead of the front.
Though better instability is across southern lower MI, a narrow
axis of better Cape (MuCape in high triple digits as far north
as US-10 tonight) does impinge on this area. And the pivoting
shortwave produces height falls aloft, before warm/moist
advection has ended. Convection will reach the MBL area
initially (late evening), then expand e and n across all of
northern MI tonight. Not anticipating a svr threat, with
substantially elevated convection. QPF of around 0.50" will be
common, especially in western and northern areas.

Have slowed down precip departure slightly very late tonight
into Saturday. Even with a somewhat slower fropa, available
instability during the daylight morning hours Saturday will be
meager. Do hang onto some showers a bit longer, and a bit
further west, Sat morning. Still have precip entirely exiting by
2 pm, with clearing skies from w to e.

Low temps tonight near 50f to the mid 50s. Highs Saturday in the
60s to mid 70s, warmest near Saginaw Bay.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 314 PM EDT Fri May 24 2024

Pattern Synopsis and Forecast: Higher pressure will build in
Saturday night, giving way to calmer winds. Skies could take a
little longer to clear out, which will keep the cooler air mass only
around 5 - 8 degrees cooler than the previous night. A surface low
over the central plains will help deepen an upper level shortwave
Sunday. A slightly stronger mid to upper level jet will carry it
northeastward towards the Great Lakes region (reaching Ontario by
Monday midday). Southeast winds will become breezy in the afternoon
hours as the surface gradient tightens from west to east and
stronger winds aloft move overhead. Models want to advect around 1
inch of PW (mean of global ensembles for Sunday/Monday), leading to
showers and thunderstorm chances Sunday night into early Monday.
Brief clearing will be seen Monday ahead of another upper level
shortwave approaching quickly, brining more rain chances for Monday
evening/night. Less confidence in storms with this round. A deeper
upper level low drops south from Canada into MN Tuesday morning.
This low swings through and continues cooler temperatures and
cloudy/rainy weather through mid week. Possibly drying out near the
end of the work week.

Primary Forecast Concerns/Key Messages: For the thunderstorm chances
Sunday night into Monday morning, the PW values around an inch check
out as Gulf moisture advection into the Mississippi River Valley
keeps getting cut off by a fairly progressive pattern as of late.
The inch of PW will be enough for some rain/shower activity however,
just maybe not enough moisture for higher instability (which is also
reflected in the models). Sunday night into Monday will likely be
what we have been seeing lately, a line of convection along the
front moving in from the west Sunday evening continuing over the CWA
through the night. The upper level low could be close enough to help
provide more lift/instability, which could hold the storms together
as they move across northern MI. However hazards expected at this
time look to be marginal and include heavy rain, lightning, small
hail, and gusty winds.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 700 PM EDT Fri May 24 2024

Showers and a few thunderstorms will continue to develop along
and ahead of an approaching cold front that will sweep thru the
Western Great Lakes region tonight into Saturday morning. VFR
conditions will drop to low VFR this evening and then to
MVFR/IFR overnight into Saturday morning as the convection
impacts Northern Michigan. Conditions will improve to VFR by
Saturday afternoon as this cold front and resulting precip exit
our region. E/SE surface winds at 10 to 15 kts tonight will
become W/NW on Saturday in the wake of the cold front.

&&

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

&&

$$

UPDATE...MLR
SHORT TERM...JZ
LONG TERM...ELD
AVIATION...MLR