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National Weather Service - Area Forecast Discussion

074
FXUS63 KAPX 290753
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
353 AM EDT Wed May 29 2024

.KEY MESSAGES...

- Chances of frost tonight and possibly Thursday night.

- Slowly increasing chances for showers and thunder later this upcoming
  weekend into next week.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 313 AM EDT Wed May 29 2024

Pattern Synopsis / Forecast:

While the upper-level flow is trending more neutral overall,
forecast area remains slightly under the influence of the mean
troffing over eastern North America. The better forcing and
moisture within the trof has shifted east of the area, leaving
cooler than normal temperatures as the primary impact. The
upstream upper-level ridging will stay west of the area through
the short-term forecast period, but an associated area of
surface high pressure will start pushing into the area by late
tonight. Northerly low-level flow to the east of the approaching
surface high is tapping a very dry air mass over central Canada.
This drier air mass supports RH values during peak diurnal
mixing this afternoon to fall to around 25%. RH values this low
would normally spark fire weather concerns, but winds will be
light enough and the significant rains earlier this week have
fuels relatively moist (especially post green-up). A more
immediate concern with the dry air mass is the potential for
cold overnight lows tonight given the good radiational cooling
conditions (light wind and clear skies). At this point overnight
lows look likely to stay above freezing but overnight lows
inland are expected to fall into the mid 30s and produce areas
of frost. Plan to hold off on any Frost Advisory at this time
per coordination with surrounding offices, but an advisory is
certainly a possibility later today.

Temperatures today are expected to top out in the 60s, with
overnight lows falling into the mid-upper 30s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 313 AM EDT Wed May 29 2024

Pattern Synopsis / Forecast:

500mb ridge axis (driven by troughing over the Canadian prairies)
set to move overhead over the course of Thursday and Friday, with
surface high pressure set to bring about dry conditions to close out
the work week. Highs expected to be in the upper 60s to mid 70s
Thursday, moderating to the lower to upper 70s by Friday. Large
differential heating between the warmer land and the colder Great
Lakes will generate a prime setup for lake breeze processes to
commence, thus locally cooler on the immediate lakeshores both days.
The larger trough will stall out and flatten over the Prairies, with
surface high pressure being forced to the east, drumming up warmer
southerly surface flow for the weekend. 500mb ridge axis will be
forced well to our east as more of a WSW to ENE zonal flow beneath
the aforementioned flattening trough commences. Though moisture
return will be rather slow to start the weekend, potential for weak
convective waves to ride this flow into the upper Great Lakes will
provide perhaps a shower or thunder chance, though most spots
probably hold dry much of the weekend as highs spike into the 70s
and 80s by Sunday. Warmth really kicks in on Monday as another ridge
axis moves into the Great Lakes ahead of another trough riding the
zonal flow regime. With 850mb temps spiking potentially as high as
16C, could result in highs well into the 80s Monday. Aforementioned
second trough will advance into western Lake Superior, lifting
northward and flattening out as it interacts with the ridge axis.
Proximity of this feature likely brings the best chance for showers
and thunder over the duration of the forecast period Monday into
Monday night.

Primary Forecast Concerns:

Thursday Night Frost: Confidence in widespread frost potential
Thursday night lowering somewhat at this juncture. Daytime temps in
the 60s and 70s on Thursday, coupled with shorter nights will force
diurnal processes that can tank temperatures to work rather
quickly... and despite decoupling winds and clear skies, most spots
outside of perhaps the more typical icebox locales (Raco, Trout
Lake, Grayling, Mio, etc) in the interior will largely remain in the
upper 30s.

Weekend Shower / Thunder Chances: Rather unimpressive wave
progressions along the zonal flow regime to begin with, coupled with
the core of forcing being kept north into western Lake Superior and
northern Ontario does not conjure up much in the way of hope for
widespread showers and thunder across the region for the weekend.
Dewpoints will increase some (into the 40s and lower 50s), which
could be just enough to drum up a few hundred joules of instability
Sunday. Overall lack of forcing probably limits convection on Sunday
to lift generated from additional lake breeze processes owing to
overall weak surface flow / more strong differential heating. Deeper
moisture (dewpoints in the upper 50s) will arrive Monday and
Tuesday, and with the passing wave to the north, a semblance of
somewhat better forcing could drum up better shower and storm
chances. Will have to see how the convective charge within this wave
evolves to get a better grasp on timing and intensity of any
resulting showers and storms across northern Michigan, which will be
examined in the coming forecast cycles considering this is 5-6 days
out from now.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1158 PM EDT Tue May 28 2024

VFR conditions are expected at all TAF sites through the issuance
period as isolated showers continue to dissipate across southern
portions of the area. Cloud cover will move out late tonight into
Wednesday morning, leaving mostly sunny/clear skies in place into
Wednesday night. Light/calm winds tonight will increase to around 10
kts out of the N/NNE on Wednesday with potential gusts to 15-20 kts
at times into the early evening hours.

&&

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

&&

$$

SHORT TERM...PBB
LONG TERM...HAD
AVIATION...DJC

NWS APX Office Area Forecast Discussion