Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 150230
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1030 PM EDT Thu Mar 14 2024

.KEY MESSAGES...

- Drier weather returns Friday with above normal temperatures
holding through Saturday.

- Near to below normal temperatures arrive Sunday and linger through
Tuesday. Some periods of light snow showers possible in this
timeframe.

&&

.AVIATION...

Shallow post frontal cold air advection ongoing across Se Mi will
sustain IFR and perhaps some lingering LIFR during the early portion
of the overnight as the cool air undercuts lingering moisture.
Ongoing areas of light rain will diminsish overnight as elevated
frontal forcing continues to wane. Model soundings suggest some
increase in the depth of the inversion overnight into Friday
morning. This will make MVFR ceilings more probable during the
course of the night. A push of drier air from the north is likely to
cause conditiosn to improve to VFR at MBS for a time. Model
soundings suggest the dry air will be slow to push into Se Mi on
Friday, but recent indications are lending support to a clearing
trend during the afternoon.

For DTW...IFR conditions are expected to hold for several more
hours, with the prospects for prevailing MVFR toward morning as a
little drier air attemps to advect in from the north.

.DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 ft or less tonight and Friday morning.
  Moderate Friday afternoon.

&&

.PREV DISCUSSION...
Issued at 802 PM EDT Thu Mar 14 2024

UPDATE...

The main instability axis is southeast of the forecast area. The risk
of evening thunderstorms is now very low and the chance of anything
severe has ended. The forecast has been updated to remove the mention
of thunderstorms.

PREV DISCUSSION...
Issued at 317 PM EDT Thu Mar 14 2024

DISCUSSION...

Northern edge of storms now working across OH have held just south
of the state line resulting in only widespread showers with some
rumbles of thunder for areas south of I-94 to the border. That said,
this area remains under a marginal risk due to the potential for
additional storm development this evening. This scenario still
carries high uncertainty as its entirely dependent on how well
instability is able to build back into southern lower MI. Satellite
shows a robust clearing trend across IL that is pushing east in IN
early this afternoon with mesoanalysis depicting between 500-1000
J/kg of SBCAPE in this region. Timing the tailedge of this cloud
puts it over Lenawee county around 20Z which offers only a modest
window for destabilization given the mid-March sun and ~3hrs until
sunset. With the surface low tracking along the warm front this
evening, should any surface based storm develop in the warm
sector/along the front, all hazards would be possible. For areas to
the north, showers and isolated thunderstorms (south of I-69)
persist through this evening before tapering off late evening with
the departure of the low.

Low pressure vacates the region late this evening ushering in drier,
slightly cooler northerly flow in its wake. Mid-level drying is
amplified Friday as the compressed eastern edge of High Plains high
pressure builds overhead. Despite this, forecast soundings continue
to suggest insufficient mixing/lower level dry air advection to
fully scour out the lingering stratus layer until Friday evening for
most areas (afternoon for the Tri-Cities). As a result, expecting a
cooler, albeit still above average, day with highs around 50 (give
or take a couple degrees on either side) for the bulk of SE MI.
Should clearing overachieve, lower to mid 50s can be expected.
Exception will be the Thumb where flow directly off Lake Huron keeps
temps in the mid to low 40s.

Mild temps briefly make a return Saturday as deeper layer southwest
flow develops in advance of a mid-upper trough digging south out of
Manitoba supporting widespread mid 50 highs (perhaps upper 50s in
the southern CWA). Aforementioned trough is then set to reach the
central Great Lakes late day Saturday with its attendant cold front
sweeping through Saturday evening/early night. Moisture quality will
be the limiting factor for precip potential given the wave`s
northern continental origin as well as the resident dry airmass over
SE MI at that point. For now, an isolated shower mention seems
appropriate. Worth noting that mid range model solutions have been
keying on window for enhanced coverage/intensity Saturday night as
the northern wave phases with the southern jet over the Ohio Valley
resulting in a region of stronger upper divergence; however, this
looks to occur shortly after the front crosses Detroit confining
this activity just to our south over Ohio.

Much colder airmass, relative to late, settles over the Great Lakes
Sunday through Tuesday keeping temperatures at or even slightly
below normal for mid-March standards. A few shortwave impulses
embedded within the parent upper trough offer low-end chances for
lake effect/enhanced snow showers during this period, particularly
Sunday night and Monday, though only minor accumulations expected at
this time. Upper jet gradually trends more zonal through the
mid/late week allowing a moderation of temperatures back to above
normal.

MARINE...

A few more hours of showers and thunderstorms occur this evening as
low pressure tracks from southern Lake Michigan eastward across Lake
Erie tonight. As the low exits eastward, Small Craft Advisories
remain in effect tonight and Friday for Saginaw Bay and southern
Lake Huron, the main concern being a surge of N/NE wind following
the system tonight. Funneling down the Bay and along the Thumb
shoreline is expected to compensate for stability that would
otherwise limit the wind response. Northerly flow that is more
marginal in character but maintains higher waves continues through
Friday ahead of high pressure that briefly settles over the region
Friday night. A larger low pressure system then approaches from
central Canada Saturday that quickly ramps up SW wind and waves to
near Small Craft thresholds. The low tracks north of Lake Huron
Saturday night while pulling multiple cold fronts across the Great
Lakes Sunday. A turn toward below normal temperatures maintains a
higher wind and wave regime into early next week.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 AM EDT Friday for LHZ421-441.

     Small Craft Advisory until 4 AM EDT Friday for LHZ442.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....SC
UPDATE.......SC
DISCUSSION...KDK
MARINE.......BT


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