Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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000
FXUS63 KDTX 140805
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
305 AM EST Sat Jan 14 2017

.DISCUSSION...

Mid level confluent flow will hold across the Great Lakes through
the weekend, sustaining sfc high pressure and dry conditions across
the region. Most of the forecast area will be blanketed beneath mid
and high clouds today, with upper level moisture transported across
the upper jet axis extending from the srn Great Lakes to New
England. The core of the arctic air that was over the region
yesterday has now shifted well to the northeast. So with a little
warmer air in the low levels, high temps today will break 30 over
much of the area. The upper jet axis will shift a little south
tonight while subtle mid level height increases occur across the nrn
plains and wrn Great Lakes on Sunday. This will allow the thicker
mid and high clouds to shift south of the forecast area. Thus better
chances for clearing tonight will support min temps down into the
teens (possibly single digits in the north). A little better
insolation on Sunday will warrant high temps a degree or two warmer
compared to today.

The cut off upper low now off the coast of northern Baja is forecast
to eject across the central plains on Monday before lifting across
the Great Lakes on Tuesday. There remains some model spread with
respect to timing this system into Michigan. Model solutions are
most divergent with respect to their handling of northern stream
energy forecast to amplify in the lee of the Canadian Rockies. While
there is agreement that these features will maintain enough
separation so as not to phase, the GFS is deeper with the northern
stream wave and thus ejects the remnant cut off circulation into
Lower Mi a little faster than the Euro and Canadian. The 00Z GFS did
trend a little slower and does not bring the lead push of deep
moisture into Se Mi until Mon afternoon. This initial surge in
higher mid level theta e air /per GFS/ late Monday will encounter
lingering dry air near the surface. While this will certainly
limit the amount /if any/ precip which reaches the ground late
Monday, the dry air will hold sfc wet bulb temps near freezing. So
a brief period of light freezing rain will be possible Mon
afternoon/evening before the degree of warm moist air advection
transitions precip to all rain. The bulk of the rain looks to
occur Mon night into early Tues with the main upper wave. Moisture
advection with this system looks to be quite good for mid January
(precip water approaching one inch). With possible elevated
convective elements, there is a chance that rainfall totals may
exceed a half inch.

The differences in the handling of the northern stream energy causes
the medium range model suite to become a little out of phase by mid
week. There does however remain strong agreement with respect to the
long wave pattern, featuring troughing across the wrn US and
building heights across the eastern US. This will support very mild
temperatures for mid winter through the duration of next week.

&&

.MARINE...

Southwest to west winds will increase to around 20 knots today over
northern Lake Huron, as a weak front moves through. West to
northwest winds behind the front briefly topping out around 25 knots
this evening. Winds then diminishing overnight, with light winds
returning on Sunday and then linger into Monday as milder air begins
to edge north into the central Great Lakes. Southerly winds
increasing to around 20 knots on Tuesday will allow for ever milder
air to reach Lake Huron, resulting in precipitation type falling
as all rain.

&&

.HYDROLOGY...

Low pressure coming out of the Southern Plains will spread rain into
southeast Michigan Monday Night into Tuesday. This system will have
a good deal of moisture to work with, but at this point, rainfall
totals are expected to range in the quarter to half an inch
range. Heavier convective showers or even a slight chance of
thunderstorms could produce localized higher totals, but no flooding
is anticipated.

&&

.PREV DISCUSSION...
Issued at 1200 AM EST Sat Jan 14 2017

AVIATION...

High pressure will maintain VFR conditions during the night while
sliding from the central Great Lakes toward the New England states.
There will be generous coverage of mid to high clouds with light
east to light and variable wind. Radar will detect some virga from
the thicker clouds over southern Michigan while measurable
precipitation remains well south of the region from early morning
through Saturday evening.

//DTW Threshold Probabilities...

* None.


&&

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

$$

DISCUSSION...SC
MARINE.......SF
HYDROLOGY....SF
AVIATION.....BT


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at www.weather.gov/detroit.



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