Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 202252
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
652 PM EDT FRI MAY 20 2016
Clouds will thicken and lower overnight into Saturday morning,
especially along I-94 corridor as low pressure tracks into the
southern Ohio Valley and band(s) of light rain pivot into the far
southern terminals. Still expect VFR conditions to hold as high
pressure to the north maintains a dry northeast flow in the low
levels. Will maintain PROB30 group for light rain DET/DTW/YIP on
Saturday morning with clearing skies at the end of the forecast
period as this system works to the east.
Ceilings may approach 5000 feet Friday morning as pockets of light
rain lift through the area. Otherwise...winds will remain light and
northeast, although speeds of 7+ kts will be possible on Saturday.
//DTW Threshold Probabilities...
* Medium confidence that ceilings will remain above 5000 kft
Issued at 301 PM EDT Fri May 20 2016
Mid level circulation evident on water vapor imagery now lifting
into west-central Illinois will continue a general eastward
downstream trajectory over the next 24 hours. Extensive mid cloud
canopy along the broadening cyclonic northern periphery will
continue to make steady inroads into SE Michigan heading into
tonight. A greater push of low level moisture advection will be
lacking, low level flow locked into an easterly component
immediately south of prevalent surface ridging centered over
northern lake Huron. However, a consolidating corridor of modest
mid level forcing/deformation will pivot into the vicinity of the
Ohio border overnight, with the potential to briefly glance across
SE Michigan between early Saturday morning and roughly midday.
Recent model guidance holding firm on this positioning, while
increasing the depth of moisture across this layer /775-600 mb/.
This will leave an underlying environment conducive for some light
shower and/or sprinkle development during this time. Greatest
potential remains along and southeast of roughly a Howell to Pontiac
to Port Huron line. Placement and duration of thicker cloud cover
toward the south will likely translate into a slightly greater north
to south gradient in high temperatures Saturday. Potential for the
Tri-Cities to push toward the mid 70s under a higher degree of
insolation, where points toward the south peak near 70.
Stronger height falls within the western periphery of an amplifying
northern stream trough digging into the eastern Great Lakes will
ease a weak backdoor front into SE Michigan Saturday Night and
Sunday. This may introduce a period of low cloud as the thermal
gradient enters Sunday morning, but appears shallow enough to either
mix out or lift into a broader diurnal cu field by afternoon.
Moisture depth seemingly lacking to warrant any precipitation
mention at this stage. The uptick in northeast/onshore flow off
Lake Huron will dampen the diurnal temperature response,
particularly across the thumb. High temperature distribution
ranging from mid 60s in the thumb to lower 70s well inland.
Sunny and warm Monday and most of Tuesday...however several waves of
low pressure are expected to move through the Great Lakes region
beginning midweek. Expect increasing clouds late Tuesday
afternoon/evening ahead of the first wave...a developing low moving
out of the central plains. The second wave is progged to push into
the area Friday afternoon/evening. Chances for showers and
thunderstorms enter the forecast on Wednesday and remain in the
forecast through the remainder of the week.
High pressure and a weak pressure gradient will sustain light winds
and tranquil weather across the marine waters through the weekend.
Light southerly winds and warmer temperatures arrive early next
week...leading to a chance of showers and thunderstorms by mid week.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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