852
FXUS63 KAPX 141917
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
317 PM EDT Fri Jun 14 2024

.KEY MESSAGES...

- Chilly tonight. Patchy fog?

- Increasing clouds and/or precip chances later Saturday.

- Dangerous heat looks increasingly more likely next week.

- Some shower/thunder potential at times next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 315 PM EDT Fri Jun 14 2024

PATTERN SYNOPSIS/FORECAST:

Broad NW flow continues over the region...as pv niblet scrapes the
EUP...and a subtle swirly in the flow crosses central MI attm. Mid
clouds associated with this latter feature generally fading from
what they were earlier as better subsidence slips into the
region...as ridge axis between the two features overtakes northern
Michigan. Diurnal heating continuing to generate some cu
areawide...as well as promote better downward momentum transport,
with gusts reaching up into the 15-20kt range thus far this
afternoon. Drier air remains largely to our northeast over
Ontario...though better mixing is promoting dewpoints into the lower
40s, especially over the interior areas. Seeing some semblance of
lake breeze action despite this...especially in the Saginaw Bay
region...with a nice shoreline-following cu field slowly trying to
sneak further inland.

Primary surface high to slip overhead tonight...with weak pv strand
slipping back northeastward through the area. Generally clear skies
and winds becoming light and variable tonight; perhaps a bit of
patchy fog, though nothing widespread expected attm. (Best chance of
this would be over the EUP and perhaps Tip of the Mitt, where they
have actually had rain in the last day or so.) High pressure should
be slow to move out Saturday, with generally east to southeast winds
early...becoming more south to southwest with time during the
afternoon as return flow pivots in; would expect warmest
temperatures to be on west of I-75...with highs making a run at 80
or so, especially in the usual downslope areas (i.e., TVC).
Generally pleasant weather expected Saturday, though clouds should
be on the increase from the west during the afternoon...with an
outside potential for some rain?

Primary Forecast Concerns:

Chilly tonight...Seasonable highs today in the 70s to upper 70s/near
80 for the Saginaw Bay region should allow for lows in the 40s to
around 50, per a typical diurnal temp spread. Airmass is a bit drier
than normal, so do think it could be colder in some of the typical
cold spots, especially over interior northern Lower, as the high
rotates overhead tonight. With pv strand pivoting back overhead as
well, do have to wonder if this will have an impact on cloud trends
(and ultimately temps). For now, though, expecting generally clear
skies and temperatures likely to drop accordingly as winds generally
go light. Perhaps even a few of the usually cold locations could
drop into the upper 30s (e.g., Grayling, etc)...though for now, not
expecting things to go much colder than this, now that we have
greened up. Additionally, potential for a teensy bit of patchy fog
tonight could keep temps from totally bottoming out as well...though
not expecting this to be very widespread by any means.

Increasing clouds and/or precip chances later Saturday...Increasing
warm advection Saturday should allow for the return of mid/high
clouds, especially along and west of I-75 through the afternoon.
(Not impossible this could temper temperatures a bit from the
current forecast.) Attm...appears any activity should remain to our
west over WI...though some guidance is more bullish with the return
of moisture and precip chances...potentially trying to develop pops
as early as later Saturday afternoon over NW Lower into the EUP
along the warm front aloft...though certainly not looking at
anything surface based attm if anything were to develop...and think
best chances will hold off till overnight Saturday night and beyond.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 315 PM EDT Fri Jun 14 2024

Pattern Synopsis/Pattern Forecast:

All eyes directed at what looks to be a significant and perhaps
prolonged heat wave next week. Expected transition of large scale
features definitely supports such, with maturation of subtropical
southeast ridging downstream of troughing digging into the
Intermountain West and Rockies. Persistent southerly flow into the
Great Lakes looks to be the result...a direct tap into the southern
Plains and desert Southwest heat dome.

Primary Forecast Concerns/Challenges:

Heat indices next week...with secondary concern centered on shower
and storm potential.

Details:

As mentioned above...all systems appear a go for a significant heat
wave to visit the Great Lakes next week. Thermal profiles on nearly
the entire deterministic and ensemble guidance suite are
impressive...reaching maturity Monday and Tuesday. Simple breadth of
warm air advection supports widespread highs topping 90 degrees both
Monday and Tuesday across much of lower Michigan (well into the 80s
north of that big bridge), with perhaps just slightly "cooler"
readings returning by Wednesday and Thursday. Low level streamline
wind analysis shows a decent tap into the Gulf of Mexico moisture
plume, allowing dewpoints to reach well into the 60s Monday through
at least Wednesday...forcing apparent temperatures at least a few
degrees hotter than actual temperatures. Unfortunately this
relatively moisture rich environment will not allow significant
cooling during the overnight hours, with lows perhaps not falling
out of the 70s for some areas, especially by Monday night and
Tuesday night. Very uncomfortable heat indeed...and perhaps
dangerously so for those working outdoors or for those who do not
have access to home cooling. Now, with all that being said...the
only possible detriment to this expected heat would be the
development of moist convection. Pattern recognition strongly
supports convective development along the ridge/trough
interface...which currently is expected to remain just to our west
for much of the period. However, have experienced countless times
when initial convective outflow boundaries force a subsequent east
displacement of this activity (although, given expected strength of
southeast ridging...that definitely may not be the case this go
around). In addition, would not be surprised to see some diurnally
forced convection in our area, especially if lake breezes can
materialize. While any convection may force actual expected highs
from being realized, not matter how you slice it...much of next week
looks uncomfortably warm at least.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 131 PM EDT Fri Jun 14 2024

Winds generally NW-NE at 5-15kt, gusting 15-20kts...as we mix higher
than expected today. Decent cu field trying to hold on this
afternoon, but struggling...cigs could drop periodically to
SCT/BKN040, to perhaps as low as SCT030. Onshore lake breezes
developing...esp south of KAPN along the Lake Huron coast, though
KAPN could get in on this as well through afternoon. Expecting winds
to diminish/skies to clear tonight...as high pressure slips
overhead. Have gone ahead and included mention of fog/br at MBL
overnight, though possible this could develop at other TAF sites
including CIU, APN in particular. Nothing widespread expected,
though. Winds become more E/SE Saturday AM, eventually shifting to
SW toward end of TAF period or beyond...with increase in mid/high
clouds from W to E through the day.

&&

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

&&

$$

SHORT TERM...FEF
LONG TERM...MSB
AVIATION...FEF