Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 180744
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
344 AM EDT WED MAY 18 2016
Expansive area of high pressure is building over the Great Lakes and
will hold over the region through the end of the week. A weaken
trough will drop through the region on Saturday producing little
more than an enhanced cloud field before high pressure returns for
the remainder of the forecast. The forecast concerns through the
week are minimal, but we will be looking at one more night of frost
potential on Wednesday night before warmer air arrives.
The cold front that dropped through the region Tuesday is well to
the south of the state now but the mid level trough remains over
head. Flow aloft will become rather stagnate the next couple days as
an upper low over the west coast stalls and strengthens. This
blocking pattern will result in an amplifying ridge over the
Mountain West region with negligible flow over the Midwest and Great
Lakes. This will all lead to a slowly modifying airmass over SE
Michigan with accumulative effects of heating/mixing each day
resulting in slight increases in temperatures each day. Working
against heating will be the northeasterly flow on the east side of
the building ridge. Eventually on Thursday night the ridge will
slide east allowing weak southerly flow to commence aiding in
low/mid level warming. Looking at 850mb temperatures, after holding
around 3C through mid week they will jump to around 5C Friday and
closer to 7C by the weekend. Expect temperatures to slowly climb
through the mid to upper 60s through mid week before breaking into
the 70s this weekend and possibly mid 70s to start next week.
While we`re on the topic of temperatures it was mentioned we may
once again have to deal with frost over part of the area. Guidance
has temperatures dropping into the upper 30s over some locations
along and north of I69. Tonight`s lows will help assess how models
are handling this new airmass and low level moisture. The day shift
will then be able to decide if we need another Frost Advisory.
On Saturday a southern stream wave will lift north through the Ohio
Valley while a mid level trough (back door cold front) dives through
the eastern lakes. At this point the southern stream wave looks to
stay far enough south of us to prevent any rain from reaching
Michigan and the airmass looks dry enough to prevent the trough from
producing anything more than enhanced cloud field.
High pressure will expand into Lake Huron from the west today, then
expand across the eastern Great Lakes on Thursday. This high will
hold steady across the region through the weekend. Light and
variable winds will prevail across the region through the forecast
period due to the associated weak gradient and increasing over lake
Issued at 1155 PM EDT Tue May 17 2016
VFR conditions will prevail throughout the forecast as high pressure
builds south into the area. Upper level clouds will decrease during
the first several hours of the forecast as a weak shortwave trough
passes southeast of the area. Diurnal cumulus, generally FEW-SCT,
can be expected again on Wednesday. Light, northeast flow will also
persist throughout the forecast with just minor backing with Lake
Breeze influence late in the day at DET/DTW/YIP.
For DTW...Some diurnal cu (5-6 kft) can be expected again Wednesday
afternoon, but drier low level air tomorrow associated with the high
pressure will keep coverage FEW-SCT. Light, northeast wind will back
more to the east with lake breeze in the 21z to 00z time frame.
//DTW Threshold Probabilities...
* Low for ceilings at or below 5000 ft Wednesday afternoon.
MI...Frost Advisory until 8 AM EDT this morning FOR MIZ047>049-053>055-
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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