005
FXUS63 KDTX 201915
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
315 PM EDT Sat Jul 20 2024

.KEY MESSAGES...

* Low coverage of showers or thunderstorms both Sunday and Monday
  afternoon.

* Greater chances for showers and thunderstorms middle of next week.

&&

.DISCUSSION...

Seasonably high amplitude flow regime will hold in place across
North America into early next week before going through one more
episode of amplification during the midweek prior to transitioning
to a more progressive state by week`s end.

The main feature of note with the next little impulse of height
falls is the ribbon of concentrated moisture along the lower
tropospheric front settling south across the Northern Great Lakes
region today. The shearing deformation within the overall weak
geopotential field will stall out across Central Lower Michigan
Sunday and Monday. There will be adequate moisture pooling within
this zone to support weakly capped modest instability generation
(~1.5 kJ/kg MLCAPE) across the Saginaw Valley and Thumb on Sunday.
Furthermore, this is the region that possesses the greatest CAPE
depth, thereby the best opportunity for convective initiation.
Furthermore, slightly unbalanced flow aloft in the entrance zone to
tropopause level jet and near surface focus near lake-breeze
features should support isolated convection during the middle and
late afternoon. Coverage should remain meager given the capping
layer and insufficient forcing to adiabatically erase. Quick pulse
nature to the convection is expected given the lack of shear, or any
flow in the column for that matter.

Only minor changes to the overall setup on Monday. Mainly the
decaying deformation axis will be perturbed by the meandering upper
circulation, currently over the Mid-Mississippi Valley, as it
wanders into the Southern Great Lakes Region. Some weak flow
imbalance aloft near the leading flank of the wave should be enough
to instigate isolated to scattered convective development once
again. The instability axis will rotate cyclonically and recenter
over interior portions of the Lower Peninsula. Greatest CAPE depth
looks to exist across the Saginaw Valley south to along and west of
the glacial ridge. Again, lack of shear and flow will support garden
variety smaller scale pulse convection. More of the same can be
expected Tuesday with continued general weak geopotential troughing
and adequate diurnal destabilization.

A more substantial deep tropospheric wave will pivot around the
Eastern North American trough into the Great Lakes region on
Wednesday. Certainly better over all forcing and better instability
density in the mid-levels to support a more vigorous convective
response. The flow remains rather weak; however, deep layer shear
does increase sufficiently to support organized convection.

&&

.MARINE...

Influence of surface high pressure wanes through the reminder of the
day as said high weakens. A weak cold front gradually sags through
the region this weekend into the beginning of next week offering
scattered shower and thunderstorm chances focused in the afternoon-
evening each day. Winds shift to N-NE behind this front though
speeds remain light at or below 10kts. Wider spread shower/storm
chances don`t arrive until midweek when a trough dives out of Canada
into the Great Lakes.

&&

.PREV DISCUSSION...
Issued at 124 PM EDT Sat Jul 20 2024

AVIATION...

Dry and stable low level conditions persist through tonight as high
pressure maintains control. This ensures VFR conditions hold, while
winds remain light and variable. Broad coverage of higher based
diurnal cu at scattered to perhaps briefly broken coverage will
linger through the latter half of the day before fading with loss of
daytime heating.

For DTW/D21 Convection...No convection is expected through the TAF
period.

DTW THRESHOLD PROBABILITIES...

* None.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

DISCUSSION...Mann
MARINE.......KDK
AVIATION.....MR


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