333
FXUS63 KDTX 301953
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
353 PM EDT Thu May 30 2024

.KEY MESSAGES...

- Another clear and chilly night ahead with lows near 40 outside of
metro Detroit, and in the upper 30s in rural or sheltered locations.

- Dry weather continues Friday and most of Saturday with a gradual
warming trend each day.

- The next chance of rain arrives late Saturday through Saturday
night.

- The weekend finishes dry and warm Sunday with highs near 80.

&&

.DISCUSSION...

Rock-solid high pressure is in full control of conditions across the
Great Lakes today. Observations throughout the day have shown the
surface ridge holding a western position resulting in maintenance of
north wind and steady low level cold advection into SE Mi. The
inbound colder air faces full sun as the mid level/500 mb ridge is
perfectly positioned over the Midwest to force strong subsidence into
the area. Despite nearly June 1st surface heating, temperatures have
struggled to reach 70 as a testament to the colder air mass in place
across the region. This sets the stage for another chilly night as
clear sky continues and as high pressure settles overhead for even
better prospects of calm wind compared to last night when there were
even a few reports of rooftop frost toward interior Thumb locations.
HREF mean projections of surface Td hold in the 30s again tonight
making another round of upper 30s lows likely by sunrise Friday
morning, although warm ground temperature guards against frost
threats to vegetation.

After the chilly morning start, temperatures rebound sharply in full
sun toward mid 70s highs Friday afternoon. These readings are at or
a couple degrees above normal for the last day of May and
accompanied by dry weather as high pressure maintains control while
drifting east of the region.

Departure of the surface high and eastward progression of the mid
level ridge become more apparent Friday night and Saturday as high
clouds thicken and wind returns to light south. The high clouds are
the first sign of the next low pressure system on schedule to spread
showers into SE Mi late Saturday and Saturday night. There are no
big issues with model performance in this medium time range given
the involvement of larger scale northern stream mid level systems.
The southern stream short wave could be embellished by upscale
growth of Plains convection during Friday, however an MCV will
likely end up being a component of the wave by Friday night into
Saturday. The system otherwise brings a generous Gulf moisture
supply in a pattern of deep SW flow theta-e advection that lifts PW
toward 1.5 inches in southern Lower Mi. Showers become widespread as
a result by late Saturday through Saturday night while the southern
stream low tracks through the Ohio valley. A rumble of thunder is
also possible in nocturnally enhanced but still weak elevated
instability.

The weekend wraps up nicely as the Ohio valley system exits to the
Atlantic coast leaving weak high pressure to fill in across the
Great Lakes. Dry weather with highs near 80 Sunday carry over into
Monday while a larger scale zonal flow transition takes place. This
typically lowers predictability on short wave features until Pacific
jet energy initiates larger scale height falls toward mid week.
Extended range model solutions show good agreement on a larger
system digging into the Rockies and Plains Tuesday night that could
reach the Great Lakes by Wednesday.

&&

.MARINE...

High pressure drifts directly overhead tonight maintaining dry
conditions and light flow. Winds shift toward southerly Friday as
the high center moves over southern Ontario with gusts expected to
remain below 20kts. High vacates early Saturday as low pressure
lifting into northern Ontario drags a cold front into the Great
Lakes. A secondary area of low pressure looks to develop along this
boundary over the Ohio Valley before tracking into the
central/southern Great Lakes latter part of the day Saturday into
early Sunday. System brings mainly showers though a few
thunderstorms will be possible over the southern half of the region.
Weak high pressure then briefly builds in late Sunday and Monday.

&&

.HYDROLOGY...

A pattern of showers moves into SE Michigan late Saturday which
continues through Saturday night when a brief period of heavy rain
is possible. Low pressure moving into the Ohio valley draws a deep
supply of Gulf moisture into the area potentially leading to
rainfall approaching totals near 1 inch before ending Sunday
morning. The system moves steadily through the area to prevent more
excessive totals, however minor flooding of prone areas and ponding
of water on roads will be possible.

&&

.PREV DISCUSSION...
Issued at 127 PM EDT Thu May 30 2024

AVIATION...

High pressure centered over the Door Peninsula of Wisconsin
maintains effectively clear skies and weak flow across the terminals
for the rest of today and overnight. Meager moisture within the 4.5-
6.0 kft AGL layer that supported areas of FEW cumulus this morning
will continue to struggle as active subsidence further dries the
column this afternoon. Light northerly winds veer toward the
northeast with time as the center of the ridge translates eastward
across Lower Michigan. Nocturnal winds then trend toward calm late
tonight and early Friday morning before becoming southerly midday
Friday. VFR conditions are expected to continue through the end of
the TAF period.

For DTW/D21 Convection...Thunderstorms are not expected during this
forecast 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...BT
MARINE.......KDK
HYDROLOGY....BT
AVIATION.....KGK


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