233
FXUS63 KAPX 161830
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
230 PM EDT Fri May 16 2025

.KEY MESSAGES...

- Warm, dry, and somewhat windy conditions results in elevated
  wildfire danger today.

- Another round of showers and storms this evening into tonight.
  Some storms may be strong to severe.

- Turning chilly with continued shower chances Saturday.

- Below normal temperatures through next week with areas of
  frost possible at times.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 229 PM EDT Fri May 16 2025

Current Overview / Pattern Synopsis:

Vertically stacked / cut off low pressure over Minnesota will slowly
trek eastward through the forecast period, with attendant secondary
cold frontal boundary sweeping through the Great Lakes this evening
into tonight. Convective response from a wave along this front well
underway across Iowa and Illinois, and with strengthening low level
jet dynamics, should bring another round of showers and thunder to
the area tonight. In the wake of the FroPa, cold air advection will
be the rule through Saturday... and with some lingering low level
moisture coupled with steep low level lapse rates (and a touch of
diurnal heating) anticipating shower coverage to fill right back in
through the day Saturday as a borderline autumn feel intrudes into
the region over the next several days.

Forecast Details:

Dry conditions hold across much of the area into this evening, with
the exception being some shower potential across the far SW as the
convective activity to our southwest intrudes. Current thoughts are
that with ample mixing and steepened low and mid level lapse rates
(latest guidance suggests the mixing layer may approach 600mb),
moisture intrusion aloft courtesy of a returning low level jet will
allow for some instability to develop this evening, bringing a
returning shower and storm chance.

The steep lapse rates aloft coupled with textbook "inverted-V" low
level convective profiles (more reminiscent of the Plains as opposed
to northern Michigan) suggest the environment may be conducive for
some gusty winds / dry microburst development to accompany as well
due tue negatively buoyant influences of rapid evaporative cooling
from water loading. Some of the initial storms may feature strong
to even severe gusts due to ample shear leading to well tilted
updrafts, but this particular threat probably wanes rather quickly
after the convective environment becomes contaminated with moisture
throughout the profile following the development of storms.

Hail will also be possible in the event that updrafts overachieve
due to strong lift in the hail growth region and ample shear. As
such, SPC has expanded the area of Marginal Risk for severe storms
(Level 1/5) to include all of northern lower Michigan. The greatest
overall storm chances favor NW lower. It should be noted that this
is a conditional threat, with non-zero higher end potential due to
aforementioned dry microburst potential. The front will pass late
this evening into tonight, taking with it the potential for thunder
across northern lower as cold air advection slowly builds due to the
occlusion, but that drier air will become more evident as that
subtle cold air advection lets lows slip to 45-55 tonight. The
occluded nature of the system will allow for prolonged rainfall
through much of the night across far NE lower into the eastern Yoop,
which may see some downpours through daybreak Saturday before the
cold air advection regime drives us to a shallower convective regime.

Eventually, anticipating cold air advection to go into overdrive
Saturday, with breezy W to NW winds bringing a raw feel to the
day... shallow convection seems a likely bet with diurnal heating,
so certainly some dry showers on the table throughout much of the
day Saturday as highs struggle to break out of the 50s for most,
with 60s becoming more likely the closer one gets to Lake Huron and
Saginaw Bay.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 229 PM EDT Fri May 16 2025

Pattern Forecast: At the start of the period Saturday night, closed
upper level low pressure is expected to be situated near the
southern Ontario/Quebec border with attendant broader area of
surface low pressure in the same vicinity. Some lingering low-level
moisture continues to wrap around the backside of that departing low
pressure Saturday night, but a general drying trend in store for the
remainder of the weekend as mid-level ridging folds over the western
Great Lakes. Canadian surface high pressure noses in from the
northwest by later Sunday and associated dry air will fight low
pressure that`s expected to trek across the Plains, mid-MS Valley
ino the Ohio Valley early-mid next week.

Forecast Details: A few lingering light/isolated showers may
continue to dot the map Saturday evening, but with a general drying
trend anticipated through Saturday night. Occasionally breezy
northwest winds continue with lows falling into the 40s area-wide.
Cooler than normal temperatures, with highs in the 50s and perhaps
low 60s on occasion in southern parts of the forecast area, are
expected to prevail Sunday through the end of the forecast period.
Pocket of colder air under ~1035mb high pressure to our north
largely responsible for this reprieve in warmer weather with the
primary focus revolving around potential frost chances, especially
Sunday night through Tuesday night. Blended guidance favors lows
each night in the lower to mid 30s over inland areas, and while that
seems feasible for now, will have to monitor overnight wind/cloud
trends for the potential of localized colder temperatures.

With respect to precip chances next week, longer range ensemble
guidance continues to favor plenty of dry time across northern
Michigan as dry northeast winds fend off associated moisture with
low pressure passing by to our south/southwest. However, by later
Wednesday/Thursday, as low pressure treks up the eastern seaboard,
at least low potential exists for that system to retrograde a bit
and provide some increased low-level wrap around moisture and
isolated to scattered shower chances.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 136 PM EDT Fri May 16 2025

VFR CIGs will be the rule through the afternoon amid a breezy SW
flow gusting to 25kts at times, especially for MBL, TVC, and MBL.
Cold front approaches this evening, bringing the development of
showers and thunderstorms after 00z, with potential for another
night of CBs. Some of these storms may produce gusty winds with
their passage. This should clear from west to east around or
just after 06z, perhaps a little later for CIU and APN. Winds
turn more westerly Saturday with MVFR to IFR CIGs at times as
cooler air and showery weather prevail.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 2 AM EDT Sunday for LMZ323-341-342-
     344>346.

&&

$$

SHORT TERM...HAD
LONG TERM...MJG
AVIATION...HAD