Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 300803
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
303 AM EST Wed Nov 30 2016
WV and IR imagery reveal shear max of interest positioned along the
eastern flank of the broad trough centered over the central US.
Inflection point noted in the southern plains, and given away by
expanding clouds in TX/OK will be the focus of synoptic scale lift
as it lifts northeast into SE Michigan today. Relatively deep layer
of 925-700mb conditional instability will reside over the forecast
area, but the 00z progs all indicate that the weak northward
moisture surge associated with this wave will mainly take place to
the east. Trimmed pops back to chc over far eastern areas where
forcing, diurnal heating, and moisture will be most favorably
superpositioned. Steepening lapse rates west of US-23 beneath the
encroaching cold core aloft will be offset by lack of moisture. An
isolated shower possible, but nothing worth an explicit wx mention.
Cold front currently hung up along the Lake Michigan shoreline will
release east as large scale support translates over Lower Michigan
this aftn. Highs a few degrees colder than yesterday, near 50,
especially further west where cold fropa will occur in early/mid
Lake Michigan activates tonight 0-1km theta-e lapse rates fall to a
modest -3 to -5C/KM. Broad scale ascent and descent moisture quality
will support deepening convective depths emanating off the lake,
particularly as an embedded shortwave tracks across the area after
06z tonight. Deepening saturated layer during this time will favor
lake effect rain and snow showers becoming likely north of M59 late
tonight into Thursday morning. No accumulation. Cool cyclonic flow
and prevalence of lake clouds will ensure temps near average through
the end of the week.
Modest southerly flow will continue across the region through the
daylight period. Winds will then increase from the southwest this
evening as cooler air begins to funnel over the lakes. Gusty
southwest winds will persist tonight and Thursday. While the gust
magnitude will largely remain just shy of cold season small craft
conditions /<30 kts/, a favorable trajectory across Saginaw Bay will
build waves sufficiently to warrant a small craft advisory across
the outer bay and along the tip of the thumb. These conditions will
likely persist into early Thursday night before easing.
Issued at 1159 PM EST Tue Nov 29 2016
With showers north of terminals now, expect dry conditions overnight
into Wednesday morning. There is still a chance of light showers on
Wednesday as low pressure tracks northeast into the eastern Great
Lakes, but it appears more likely that most of this precipitation
will edge east of area. With this in mind, will introduce a less
pessimistic ceiling and visibility forecast with a narrower window
of mvfr to lower vfr cigs and/or vsbys.
For DTW...While mvfr ceilings look to be limited to Wednesday
morning to early afternoon, 5000 foot cigs will become increasingly
likely overnight and may persist closer to 00z Thursday evening.
Light southeast flow overnight will veer to south in the morning and
southwest by midday Wednesday.
//DTW Threshold Probabilities...
* High for ceilings aob 5000 feet late tonight and Wednesday.
Lake Huron...Small Craft Advisory from 10 PM this evening to 10 PM EST Thursday
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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