Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000
FXUS63 KDTX 241646
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1246 PM EDT Mon Apr 24 2017

.AVIATION...

Modest easterly flow will exist through the latter half of the day,
sustained south of high pressure.  Intermittent gustiness to this
wind may emerge at the height of peak heating, but with gusts below
20 kts.  Otherwise, this dry and stable environment will yield a
clear sky through the evening period.  Extensive canopy of mid cloud
tied an expanding area of Atlantic moisture will pivot northwest and
into the southeast Michigan airspace overnight.  This will bring an
increasing ceiling at 6 to 8 kft.  There is at least some potential
for a lower ceiling to emerge by Tuesday morning /low VFR to MVFR/
depending on the degree of moisture transport, but confidence in
this evolution remains low at this time.

For DTW...Persistent east-northeast wind will continue to support
northeast operations through this evening.  Mid cloud thickens
overnight and Tuesday morning, likely carrying cigs in the 6 to 8k
ft range...at least initially.  Low confidence on a subsequent drop
in ceiling heights below 5000 ft with time through the morning.

//DTW THRESHOLD PROBABILITIES...

* Low for ceiling at or below 5000 ft late tonight and Tuesday

&&

.PREV DISCUSSION...
Issued at 349 AM EDT Mon Apr 24 2017

DISCUSSION...

Another quiet day around southeast MI as high pressure sandwiched
in between a cutoff low to our south and the main baroclinic zone
laid out to our north. Thermal profile should remain very close to
what we saw Sunday as the airmass remains locked in place. Light
eastern flow off the lakes around the southern side of the high will
keep shoreline areas a bit cooler today, but strong diurnal mixing
will allow most locations to make a run at 70 again. Upper 60s will
be more common for inland areas with Lake Huron shoreline areas
lingering in the 50s.

Strong blocking ridge over the western Atlantic combined with
potentially a +150 knot jet digging southwest through the northwest
conus will lead to an amplification of the longwave pattern across
the US. Models have consistently kept us on the warm side of the
baroclinic zone which will keep temperatures above normal through
the forecast. 850mb temperatures will be fairly steady in the 5-10C
range through the week with the exception of Wednesday when the
trough nudges closer and 50 knot 850mb low level jet lifts into
southern MI providing a WAA boost into the mid/upper 70s. Otherwise
expect temps to run 5-10 degrees above normal this week.

Precipitation will be hard to come by through most of the week.
Resident airmass is sporting pwats around 0.2 inches and are
forecast to stay below a half inch through tonight. Moisture will
then begin to increase ahead of the trough drifting ever so slowly
eastward, but remaining well to the west up through the Midwest and
western Great Lakes. Challenge in the coming days will be to assess
how far east the precipitation will extend into the dry airmass over
southern MI...and when it finally reaches eastern lower MI. Models
have continually slowed the progress of this trough over the last
few days keeping the showers over western lower. The main fgen and
waves lifting up along the front look to stay to the west through
Wednesday night. Could very well see some showers and thunderstorms
clipping the Saginaw Valley on Wednesday and Wednesday night but the
best changes will come on Thursday as the upper low releases and
swings up through the region and sends the front through on
Thursday.

Additional rain chances will come through the weekend as the stalled
boundary lifts back over or near SE MI. We`ll have to watch for
additional shortwaves to ride up along the boundary for periodic
chances of precipitation.

MARINE...

The combination of surface high pressure over portions of central
and northern Canada and a broad trough of low pressure over the
central Plains states will lead to stiff easterly winds today over
the region. East winds of 20 to 25 knots are expected over the far
northern Lake Huron basin as well as Lake St Clair and the western
basin of Lake Erie. For the southern basin of Lake Huron, winds
today are expected to range between 15 and 20 knots. Winds are
forecasted to shift to the southeast on Tuesday and hold that
trajectory for a good chunk of this upcoming week. While greater
stability will come with southeasterly flow, it appears that winds
will persist in the 15 to 20 knot range for much of the marine
areas. Winds are not expected to turn southwesterly until sometime
Thursday.

&&

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

$$

AVIATION.....MR
DISCUSSION...DRK
MARINE.......CB


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