Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 232310
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
610 PM EST Tue Jan 23 2018


.AVIATION...

Remnant light snow/freezing drizzle will end around PTK and DET by
00Z as a sfc cold front and mid level moisture exit to the east of
the region. Regional satellite/sfc obs show ample stratus blanketing
lower Mi. A deepening low level inversion and lingering low level
cyclonic flow will hold stratus in place across Se Mi through at
least daybreak Wed. Ongoing low level cold air advection will result
in a subtle rise in the inversion heights. This should result in a
subtle trend toward cigs rising into the 2-3k ft range late this
evening into the overnight.

For DTW...Ceilings look to fluctuate above and below 2k feet for at
least the next couple of hours. There are higher probabilities for
cigs to be above 2k ft overnight. The onset of nighttime cooling and
weakening sfc gradient will result in a slow decrease in the
westerly winds during the night, with a direction shift toward 290
to 300 degrees expected between 01Z and 02Z.

/DTW THRESHOLD PROBABILITIES...

* High for ceilings less than 5000 ft tonight and Wed morning.
  Moderate Wed afternoon.

&&

.PREV DISCUSSION...
Issued at 338 PM EST Tue Jan 23 2018

DISCUSSION...

Surface trough transiting the CWA is supporting light snow showers
this afternoon leading to nothing more than minor accums. Coverage
and intensity will continue to decrease as large scale forcing and
better moisture strips east. Cold advection within gusty northwest
wind will continue through the night as 850mb temps fall from around
-8C at press time to -13C Wednesday morning. Temps in the mid to
upper 20s over Wisconsin and northern Lower support going forecast
lows in the upper teens and low 20s, except the far south CWA where
cold fropa has yet to occur this aftn and arrival of coldest air
will be delayed. Some potential for lower temps across the north as
trailing dry advection, which is already advancing the back edge of
lake clouds over Lake Superior, works into the area from the NW and
potentially clears out low cloud as the gradient slackens post 06z.
A run to the low teens is not out of the question in the Thumb, but
remained conservative given uncertainties and lack of snowcover.

Thermal trough directly overhead to start Wednesday will ensure a
low ceiling on temps. Subsidence beneath incoming upper ridge will
reinforce existing inversion, supporting a more pessimistic cloud
forecast overall for Wednesday, especially considering mid/high
clouds streaming associated with the trough over the northern Great
Plains will be streaming overhead. No qualms with a mid to upper 20s
forecast for highs, keeping in mind some underachieving potential
will exist conditional on opacity/coverage of boundary layer clouds.
Confluent upper flow in advance of upper ridging will force surface
high pressure across the area early Thursday, scouring any remaining
low clouds before emerging return flow signals the arrival of a
shallow warm front likely to cause low clouds to return for at least
part of the day Thurs and a modest recovery in temps of about +5
over Wednesday`s values.

An upper level ridge axis crossing the region on Friday and low
pressure moving eastward through central Ontario will bring
increasing southwesterly flow through the day allowing highs to
approach 50 under mostly sunny skies. The low pressure will then
pull a cold front slowly eastward across Lower Michigan on Saturday.
Increasing moisture transport ahead of the front will bring rain
shower chances late Friday that will continue throughout Saturday as
temperatures remain well above average in the upper 30s to mid 40s.
Model solutions continue to differ on the exact details of frontal
timing and where the greatest moisture transport will take place
ahead of the front. The GFS keeps the bulk of moisture east of SE
Michigan on Saturday while the Euro and CMC pull moisture directly
over SE Michigan late Saturday. After the frontal passage,
temperatures will fall slightly into the 30s on Sunday before a
secondary cold front brings a stronger push of cold air to the
region late Sunday into Monday. A chance for snow showers will
accompany the second frontal passage as temperatures return closer
to average with highs in the low 30s and lows in the upper 10s by
Monday.

MARINE...

Low pressure centered over central Lake Huron this morning will lift
northeast into Ontario during the daylight period. Moderate
northerly winds currently residing north of this low over the north
half of lake Huron will expand across the entire lake Huron basin as
the low exits. This will be accompanied by colder air, which may
lead to a brief period of gusts to near gales late this afternoon
through early tonight. Winds and gusts will decrease Wednesday as
weak high pressure lifts across the region. Relatively light winds
will remain in place through the end of the week. Another increase
in winds will come for the weekend.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning until 10 PM EST this evening for LHZ362-363.

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

$$

AVIATION.....SC
DISCUSSION...JVC/JD
MARINE.......DG


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at www.weather.gov/detroit.



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