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000
FXUS63 KDTX 241703
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
103 PM EDT Wed Apr 24 2024

.KEY MESSAGES...

- A Freeze Warning is in effect for all of southeast MI tonight
through early Thursday morning as temperatures dip into the mid to
upper 20s.

- Dry conditions with a warming trend bring high temperatures to the
50s on Thursday and 60s on Friday.

- Showers are likely Friday night with windy and warm conditions
this weekend. There is low confidence in shower and thunderstorm
potential Saturday and Sunday.

&&

.AVIATION...

High pressure inbound from northern Ontario brings cool and dry air
to Lower Mi this afternoon. North wind gusting around 20 knots lifts
remain MVFR ceiling into low end VFR across SE MI by mid afternoon
while also clearing from north to south late in the day. Clear sky
and light wind follow the high pressure center across the Great
Lakes tonight and Thursday. Clouds are limited to thin cirrus while
light east wind sets up with some lake breeze augmentation Thursday
afternoon.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet or less through mid afternoon.

&&

.PREV DISCUSSION...
Issued at 425 AM EDT Wed Apr 24 2024

DISCUSSION...

A strong southward advancing cold front marked by a sharp northerly
wind shift is approaching the Thumb and Tri-Cities this morning,
driven by the departure of a mid-level trough axis. Temps will
settle into the lower 30s (north) to lower 40s (south), setting the
stage for a chilly late April day. Stratus will canopy the area
within the active cold advection this morning and stifle early day
warming, limiting high temp prospects to the 40s (north) and lower
50s (south). Some areas along the Lake Huron shoreline will likely
top out in the upper 30s. Meanwhile, winds will remain brisk out of
the north at around 15 to 25 mph this morning before gradually
tapering off this afternoon. This keeps a wintry bite around with
apparent temps holding in the 30s for much of the day. Dry air will
eventually erode the stratus deck north to south midday, with
sunshine and weaker winds then offering some relief.

Slow but steady mid-level height rebounds complement the dry
advection through this evening with a ridge of sfc high pressure
building in from the west. High confidence in sub freezing temps
overnight into Wednesday morning given clear skies indicated by
PWATs near the 1st percentile in NAEFS climo, very light winds,
thermal trough overhead, and sfc dew points dropping into the
teens/20s to create a very favorable radiational cooling
environment. A significant portion of HREF members bring a hard sub
28 degree freeze to most of the area north of the glacial ridge.
While a freeze like this is not uncommon for late April, the mild
winter and spring brought an early start to the growing season which
means impacts may be more pronounced and any sensitive vegetation
will be at risk. A Freeze Warning is in effect from midnight through
8 AM.

The 850mb thermal trough remains overhead on Thursday, but ridging
maintains sunny skies that help boost temps to the mid 50s for a
high. The dry environment means another cool night Thursday night
and interior areas may see lows near the freezing mark, but a
widespread hard freeze does not look likely. Benign weather carries
through much of Friday as the upper ridge axis passes over the Great
Lakes. During this time a low will be deepening over the central
Plains with its warm conveyor directed from the western Gulf up the
Mississippi Valley. As the low reaches eastern NE late Friday and
the ridge axis passes to our east, the warm advective wing will
spread overhead and bring a round of showers Friday evening/night.
The LLJ veers through overnight, peaking near 50 kt with strong
moisture transport bringing relatively high confidence in the
showers. Lapse rates look poor in available guidance, but some
embedded thunderstorms may be possible given relatively strong lift
spreading in.

Saturday will see the warm sector take residence over the area with
relatively low confidence on convective trends during this period.
Overall setup seems to favor drier conditions as mid-level ridging
builds into the area which keeps the profile capped. The LLJ will
remain positioned overhead which brings a strong southwest wind on
Saturday, likely gusting in excess of 30 mph. 850mb temps rising to
the lower teens C make high temps in the 70s likely. As the first
low tracks across Lake Superior on Saturday night, a second low
develops along the frontal zone draped across the central Plains.
This low takes a similar track to our west, ensuring we stay within
the warm sector through the weekend. Convective trends carry
relatively low predictability into Sunday with capping concerns, but
higher confidence in showers/storms arises on Monday as the cold
front moves through.

MARINE...

Brisk northerly flow in the wake of the earlier cold front will
commence this morning. There also remains a low-end potential for
gusts to gales while lapse rates steepen and forecast soundings are
well-mixed once stronger LLJ winds clip central Lake Huron.
Hazardous conditions for small craft can be expected on Lake Huron
today. Gradient winds trend lower midday Wednesday before high
pressure starts building into the Great Lakes. More favorable marine
conditions are expected Thursday with sustained ridging until
Friday. Unsettled weather returns Saturday, dependent on trajectory
of a large low pressure system ejecting from The Plains.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...Freeze Warning from midnight tonight to 8 AM EDT Thursday for
     MIZ047>049-053>055-060>063-068>070-075-076-082-083.

Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422-
     441>443.

Lake St Clair...Small Craft Advisory until 10 PM EDT this evening for LCZ460.

Michigan waters of Lake Erie...None.

&&

$$

AVIATION.....BT
DISCUSSION...TF
MARINE.......KGK


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at www.weather.gov/detroit.