Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 182048
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
348 PM EST Sat Feb 18 2017
Main story for week is the continued warm spell as high temperatures
will run about 15-20 degrees above normal for mid/late February.
Impressive warm up today resulted in records being set at all 3
climate sites (DTW, FNT, MBS) though official values may not be
reached til after this discussion is published. Regardless, as of
3pm all sites had exceeded their record values (FNT by +9F
A surface low tracking across Ontario into Quebec today is pulling a
weak cold front through lower MI. The front is barely discernible
looking at surface temps and dewpoints but there is a slight wind
shift with it. It`s more easily picked up on water vapor imagery as
drier and cooler air aloft with more northwesterly flow advects into
the region. Overall the longwave pattern changes little through
Sunday as strong trough over the west coast keeps re-building and
strengthening the ridge over the central plains. The Great Lakes
will remain on the backside of the ridge Sunday with the trough axis
swinging through Monday afternoon when a strong jet dislodges the
deep trough to the west. High pressure at the surface over Canada
will fill in behind the exiting surface low under the building
ridge. This will lead to another warm day but the position of the
high will result in more northerly flow thus it will be a bit cooler
than today. Temps should range from near 60 at the Ohio border to
the mid 40s across mid MI.
Monday will start off similar to Sunday with 850mb temps hovering
around 6C with west/northwesterly flow aloft keeping the feed of
warm air from upstream. Clouds will be on the increase as the trough
and cold front approach, being forced east by a strong jet making
landfall over California early Monday. Models are hinting at some
prefrontal activity/showers passing through early Monday evening but
better forcing and most widespread activity should hold off til
closer to Tuesday Morning. Strengthening southwest flow ahead of the
front will keep temps up Monday night, likely above freezing for all
locations so precip should fall as all rain.
Rain chances continue on Tuesday as a frontal boundary slides across
the area. Chances for rain then diminish by Tuesday evening as the
front moves east bringing a brief dry period for Wednesday into
early Thursday. Weather conditions then start to become more active
as models are advertising a strong system moving up from the central
plains Thursday and impacting the region into the weekend. This
system has the potential to bring windy and rainy conditions as it
moves up towards the northeast. Temperatures through the extended
will remain above normal through the end of the week before cooler
air filters back in behind the departing low next weekend.
Moderate west to northwest flow to persist through early Sunday.
Winds ease throughout Sunday as high pressure builds in from the
west. This will hold wind gusts below 25 kts over most areas
throughout this time. Winds then turn southeasterly and gradually
increase Monday and Monday night.
Issued at 442 AM EST Sat Feb 18 2017
Wind shear will abate early in the forecast period due to the
coincident weakening of the low-level wind field and deepening of
the diurnal mixed layer. This will eventually translate into wind
gusts around 20 kts mixing to the surface by early this afternoon.
Conditions otherwise favorable with cloudless skies save for some
//DTW THRESHOLD PROBABILITIES...
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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