Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 202239
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
639 PM EDT Thu Apr 20 2017
Residual showers/thunderstorms will be well east of the termainals
by 00Z, with the sfc cold front set to pass through around 00Z. Post
frontal westerly winds will increase during the overnight as low
level cold air advection ensues, eroding a shallow near sfc stable
layer. Ceilings will undergo a brief post frontal improvement before
low level moisture funnels back into Se Mi under a developing low
level inversion. This will result in an expanding MVFR based stratus
deck late this evening into the overnight.
For DTW...With a little drier post frontal airmass upstream of
Detroit, the lower clouds may take until late in the evening to fill
//DTW THRESHOLD PROBABILITIES...
* High in ceilings below 5000 ft through taf period.
Issued at 350 PM EDT Thu Apr 20 2017
The ongoing convective cluster over Lower Michigan is expected to be
followed by one more round of storms along and ahead of the cold
front as it moves through the region during late afternoon and early
evening. Severe thunderstorm watch 151 is in effect until 8 PM.
Ongoing activity continues to have some potential for organization
along and south of the I-96 corridor which is about the position of
the surface warm front at press time. So far, this activity has been
marginally severe as 0-1km MLCAPE remained less than 1000 J/kg.
Similar concerns exist for the last phase of the event as the system
attempts to recover some instability between the ongoing convection
and the cold front over SW Lower Michigan. Discrete storms observed
over Indiana at press time are expected to develop northward into
Lower Michigan with a chance of gradually evolving into linear mode
thanks to increasing 0-6km effect shear. The improved wind profile
and larger scale vertical motion field will be produced by the upper
level wave moving into the region while the surface low moves into
northern Lower Michigan. This leaves a narrow window of opportunity
open for severe weather in our area through the watch expiration
and before the front exits into Ohio/Ontario.
Wraparound moisture associated with the low pressure system
will remain over the northern Great Lakes during Friday. This will
be followed by high pressure that will keep Southeast Michigan dry
while producing chilly nights this weekend and for the start of next
week. Low temperatures in the mid to upper 30s will be common each
night while typically colder locations making a run at freezing.
Daytime temperatures are projected to be in the upper 50s to around
60 degrees through Monday before readings warm back into the 60s by
middle of next week. The next chances for any precipitation is
expected by Tuesday as a shortwave skirts along the northern Great
Surface low over central Lake Michigan will track across northern
Lane Huron tonight. Strong easterly flow will weaken somewhat
tonight as the winds veer to the west by morning. Winds will
increase during the day Friday to about 15 to 20 knots while
veering to the northwest as high pressure approaches. Winds and
waves may be high enough to warrant small craft advisories for the
nearshores of southern Lake Huron Friday. Winds will weaken
over the weekend as high pressure crosses the area.
Lake Huron...Small Craft Advisory until 10 AM EDT Friday for LHZ421-441.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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