Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
808
FXUS63 KDTX 201028
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
628 AM EDT Sun May 20 2018


.AVIATION...

Light north-northeast winds today coming off Lake Huron expected to
help maintain low clouds through the majority of the day, although
diurnal heating will allow for cloud bases to lift, likely reaching
into borderline MVFR/lower VFR this afternoon. Confidence in low
clouds is not as high at MBS/FNT. A few sprinkles not out question
as well as dissipating showers over western Great Lakes advance
east. Looks like there will be a sufficient dry push this evening to
break up the low clouds from north to south, with still some mid
clouds lingering through the night, as frontal boundary persists
near southern Michigan border.

For DTW...Latest guidance suggests low clouds holding through the
day, with borderline MVFR/low VFR even lingering this evening.

.DTW THRESHOLD PROBABILITIES...

* High for cigs aob 5000 ft today, medium this evening, then low.

&&

.PREV DISCUSSION...
Issued at 302 AM EDT Sun May 20 2018

DISCUSSION...

An elongated region of sfc high pressure will expand from northern
Minnesota/Lake Superior this morning into northern Lower Mi this
afternoon within mid level confluent flow across the northern lakes.
There has already been a push of shallow cool air across Se Mi
within the low level north-northwest flow preceding the sfc ridge
axis. This shallow cool layer has led to a deepening low level
inversion, supporting ample low clouds and fairly widespread
drizzle. Persistent low level northerly flow this morning will
advect drier boundary layer across Se Mi, this will end the drizzle
from north to south across the area during the early morning hours.

The cluster of showers/thunderstorms across SW Wisconsin overnight
have struggled to to make much progress to the east. There will be a
push of lower mid level theta e air across srn Mi from the north
today which will hold any semblance of elevated instability well to
the south and west of the area. There will also be subtle mid level
height rises across Lower Mi through the day. These factors will
make it unlikely for ongoing convective activity across srn WI to
advance into Se MI. While low clouds will tend to diminish from
north to south across the area during the course of the day, the
shallow cool air will limit mixing depths and likely hold afternoon
highs mainly in the 60s, with much cooler readings along the Lake
Huron shoreline.

The sfc high will build into Se Mi tonight. Mid/high level clouds
will likely inhibit radiational cooling potential across the
southern half of the forecast area. The likelihood for clearing skies
across the Saginaw Valley and thumb combined with the dry airmass
will warrant min temps into the low 40s (with some upper 30s
possible across the thumb).

There is a fair amount of model divergence with respect to timing
and amplitude of short wave impulses lifting out of the upper
Midwest and traversing srn Mi Monday into Tuesday. This will affect
the strength of mid level southwest flow which in turn will
determine the degree of mid level moisture/instability advection
into Se Mi. In light of the confluent flow overhead, preference lies
with those solutions which dampen the upper energy more
significantly, thereby only supporting just low chances of
convection (mainly south of M-59). High pressure will strengthen
across the Great Lakes midweek behind an amplifying mid level trough
over eastern Canada, supporting dry conditions across Se Mi. Mid
level ridging will then expand across the Great Lakes toward the end
of the week, leading to a steady warming trend.

MARINE...

Light winds today as high pressure builds into the area. Light winds
will persist through at least Wednesday, as high pressure more or
less holds over Lake Huron. Chance of showers and thunderstorms
early next week will be mainly confined to Lake St. Clair and Lake
Erie.

&&

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

$$

AVIATION.....SF
DISCUSSION...SC
MARINE.......SF


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.