192
FXUS63 KDTX 020001
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
801 PM EDT Sat Jun 1 2024

.KEY MESSAGES...

- Showers move in this evening and continue overnight and Sunday
morning. Rainfall totals generally range between 0.25" to 0.75".

- A warming trend continues Sunday and Monday with highs in the
lower 80s expected Monday afternoon.

- Unsettled weather returns Tuesday and lasts through mid-week with
periods of showers and thunderstorms.

&&

.AVIATION...

VFR rain showers are spreading across terminals to start this TAF
period with ceilings mostly above 5 kft. Observations show MVFR
ceilings trailing the lead wave of light showers reaching western
portions of Michigan and northern Indiana. These ceilings will
spread across terminals by 07Z or shortly before a rain showers
continue. Slight uptick in heavier shower activity late tonight will
bring potential for MVFR VSBYs as well. The influx of low level
moisture will hold the lower stratus and possibly support some
fog/drizzle through the morning hours as surface low pressure moves
through southeast Michigan. Conditions will gradually improve
tomorrow afternoon into the evening.

For DTW/D21 Convection...There has been no thunderstorms observed in
Michigan with the arrival of rainfall thus far. The lack of
instability should greatly limit the thunder potential through
tonight.

DTW THRESHOLD PROBABILITIES...

* Low for thunderstorms tonight.

* High for ceilings at or below 5,000 feet tonight and tomorrow
  morning.

&&

.PREV DISCUSSION...
Issued at 313 PM EDT Sat Jun 1 2024

DISCUSSION...

A plume of showers extends from the Gulf coast to the upper Midwest
this afternoon as a southern stream short wave circulation phases
with the larger northern stream/Canadian mid level trough/low. Model
analysis fields indicate a broad moisture axis/theta-e ridge
extending south to north along and ahead of the associated surface
pressure system tapping plentiful Gulf moisture. Model fields match
up well with afternoon hourly mesoanalyses that measure 1.5 inch PW
reaching up to the Chicago area at forecast issuance. The foundation
of moisture transport is responsible for the sizable footprint of
showers with localized enhancement in and around the southern stream
mid level circulation projected to move across southern Lower Mi
tonight. So far, the absence of thunderstorms is a notable aspect of
the pattern commensurate with mesoanalysis of sub 6 C/km 700-500 mb
lapse rate and surface based CAPE hovering around 500 J/kg. Some
recovery of instability is likely south of the Ohio valley this
afternoon but remains an issue northward across Lower Mi through the
evening. Some elevated/nocturnal recovery is possible across the area
late tonight as moisture transport remains strong enough to be a
destabilizing factor into Sunday morning. This, along with forcing
tied to the mid level circulation, otherwise contribute to widespread
showers while keeping a stray rumble of thunder possible.

A model trend materializing for Sunday is slower exit timing on the
surface pressure system from SE Mi in the afternoon. Hi-res and
regional models are latching on to this idea as a source for
redevelopment or maintenance of scattered showers, especially during
peak heating similar to the response in the MO/IL/IA area today.
Larger scale forcing does increasingly become an opposing factor
mainly in terms of mid level subsidence in the downstream vicinity
of the short wave ridge. Opted to hold on to a low end chance POP
toward the eastern border region, very dependent on daytime heating,
considering upstream observations today.

The influence of the inbound mid level ridge and surface high
pressure gain traction Sunday night for dry weather Sunday night and
Monday. Mixed high clouds are the dominant sky cover Monday which
allows afternoon temperatures a chance to reach the lower 80s under
the broader long wave ridge to zonal flow transition. Today`s models
then show a reasonable consensus on continuing a pattern change
toward mid week. Pacific upper jet energy digging into the west
coast initiates Plains height falls Tuesday into an impressive
affecting the Great Lakes by Wednesday.

MARINE...

A slow moving low pressure system will move across southern Lake
Michigan this evening, then will advance toward southern Lake Huron
on Sunday before weakening. This system will drive an area of rain
across the lakes tonight through Sunday morning. As the low pressure
system weakens, high pressure will develop across the region Sunday
night into Monday. Winds will generally remain light given the weak
gradient across the eastern lakes. An approaching warm front will
bring a chance of showers and thunderstorms to the region on
Tuesday. Southeast wind gusts approaching 20 knots are possible as
the gradient increases ahead of this front. The warm front will then
be followed by a strong cold front on Wednesday, sustaining the
chances for thunderstorms.

HYDROLOGY...

Showers and a stray thunderstorm in the Midwest and Ohio valley
today are on schedule to move across Lower Michigan tonight and
Sunday. The activity is fueled by Gulf moisture feeding into low
pressure and a weakening front moving across the region. Rainfall
amounts between 0.25" to 0.75" are expected, although localized
higher amounts around 1 inch are not out of the question. Brief and
minor flooding of prone urban and low-lying areas, ponding of water
on roadways, and rises in area rivers are possible in this scenario
until the pattern becomes scattered and exits eastward Sunday
afternoon.

&&

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

$$

AVIATION.....AA
DISCUSSION...BT
MARINE.......SC
HYDROLOGY....BT


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