mi discuss
Office: MQT
FXUS63 KMQT 172349
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
749 PM EDT Fri Aug 17 2018
.SHORT TERM...(This evening through Saturday)
Issued at 354 PM EDT FRI AUG 17 2018
Satellite imagery showed the leading edge of the smoke from the
Western North American fires enchroaching from the west towards the
Upper Peninsula, and eventually reaching the Central UP this
afternoon. Smoke was fortunately not mixing down to the surface for
most areas, although it was significantly limiting the light
filtering through to the surface. This has reduced the surface
heating this afternoon for portions of the UP, otherwise locations
downwind of the smoke shield have seen temps warm into the lower
80s. Minimal pressure gradient from the northeast has allowed the
onshore flow to persist for areas along the Superior shoreline,
which has held temps in the upper 60s to around 70 this afternoon.
Expect the overnight hours to be relatively quiet, with the only
challenge being fog development and placement. Expect the fog to
slowly develop from IWD to IMT, then begin to spread north of that
line towards CMX. Guidance has exhibited a low confidence on
intensity, so expect at this time VSBYs to fall to around 2-3 miles
and persist until daybreak. The wildcard will be smoke coverage, and
an area of stratus that is trying to slide south across Lake
Superior. If this stratus deck slows over the UP this evening, this
will most likely minimize the fog coverage and keep surface temps
warmer. Have lows tonight falling into the 50s for most locations.
Saturday will continue to be a relatively quiet day, with dry
weather expected yet again under diffluent flow aloft. Mid-lvl
trough axis will be displaced to the east of the area, with a quasi-
cool northwest flow overhead. This should produce partly cloudy
skies with temps in the 70s for most locations across the UP. The
exception will be areas adjacent to Lake Superior that could see
onshore flow develop earlier and hold temps in the 60s.
.LONG TERM...(Saturday night through Friday)
Issued at 406 PM EDT FRI AUG 17 2018
During the long term, there are 2 main systems that will affect the
weather over the Upper Lakes, the first early next week and the
second late week. Vigorous shortwave currently moving across the
Pacific NW will track ese into the central Plains by Mon morning. As
this wave moves to the Plains, strong height rises along the w coast
of Canada into AK will begin to force trof amplification into
central N America early next week. Shortwave dropping se in
association with this amplification will in turn force the Plains
wave ne across the Great Lakes region on Tue and on into eastern
Canada on Wed. Degree of interaction btwn the 2 waves will dictate
track/strength of what may end up being an unusually deep sfc low
for Aug as it tracks ne across the Great Lakes region...a preview of
the Fall storm season which is quickly approaching. For Upper MI, at
least some showers will occur here early next week, either
associated the ne moving wave or the se moving wave. Whether or not
the heavier, steadier rain closer to the ne moving sfc low impacts
the fcst area remains to be seen. Above normal temps prevailing
ahead of the system will only briefly fall back to near/slighly blo
normal behind it as the amplifying mid-level trof quickly swings
eastward. A deep mid-level low is fcst to settle over Hudson Bay
during the mid-week period. Shortwave swinging around this feature
may force a cold front s into the Upper Lakes on Thu, but that looks
doubtful. What it will do is bring a quick warmup midweek under
developing westerly flow s of the mid-level low. For being well out
in the model runs, medium range guidance is in decent agreement
showing the next more notable shortwave tracking e toward the Upper
Lakes late week, bringing the next chc of showers at that time.
Beginning Sat night/Sun, dry/warm weather will be the rule as we
await the Plains shortwave and/or shortwave dropping se thru Canada.
Expect min temps in the 50s/lwr 60s Sat night. Closer to departing
sfc high, traditional cold spots over the interior e half will
probably fall blo 50F. Could be the typical late summer radiation
fog patches Sat night under clear skies/calm wind, especially in low
swampy areas and around rivers/lakes. Temps will reach the low/mid
80s on Sun, locally cooler along the Great Lakes in the aftn.
Organizing sfc low over the central Plains Sun night will deepen as
it lifts ne, passing across Lwr MI on Tue. While track of sfc low is
fairly well agreed upon among the models, the complicated
interaction of the 2 shortwaves involved leads to lower confidence
in the depth of the sfc low and how expansive the evolving pcpn
shield will be, and that uncertainty is further complicated at this
time of year by how convection evolves with the southern wave.
Whether the hvy pcpn consistently showed by models along/just n of
sfc low track expands far enough n to impact the fcst area remains
to be seen. Last few days of model runs, especially ECMWF, suggest
the se part of the fcst area has best chc of seeing at least mdt
pcpn amounts. Record low sea level pressures in the Upper Lakes in
the month of Aug are in the mid and upper 990s mb, so some
skepticism is required for model runs that are wrapped up with the
sfc low, dipping pres blo 1000mb as it moves across Lwr MI. Will
certainly be something to monitor as this will impact winds most
notably over the Great Lakes. In any event, sfc cold front
associated with trof amplifying s thru Canada will likely push over
Upper MI Sun night and may clear the fcst area on Mon or hang up
over se portions of the area. Upper divergence associated with right
entrance of upper jet across northern Ontario into northern Quebec
should aid development of at least sct shra along/behind front as it
slows down/stalls out Sun night/Mon. Could be some thunder, but
there's not a lot of instability. As southern wave/sfc low then lift
ne, mdt/hvy pcpn will spread into the Great Lakes Mon night/Tue
morning. Se half of the fcst area has the best chc of getting into
this heavier pcpn. Pcpn will then quickly shift e and ne out of the
area Tue aftn/night. After a cooler Tue with clouds/shra, Wed will
turn warmer/sunny as mid-level trof shifts eastward.
Thu looks warm, provided a cold front does not drop s into the area
as alluded to above. Max temps around 80F will be the rule. Next
shortwave should arrive from the w Fri/Sat, bringing the next chc of
shra.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 749 PM EDT FRI AUG 17 2018
Fog will become the main concern tonight, but that should be
confined to KIWD. Expect Vis to drop below a mile with accompanying
low ceilings. Smoke will continue to cover the area through
Saturday, but should not be as dense as this evening and should
remain aloft with no surface visibility restrictions expected.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 354 PM EDT FRI AUG 17 2018
Winds will generally be less than 15 kts thru tonight/Sunday;
however, the typical funnelling and tightening across the far
western arm of Lake Superior will see locally higher speeds into DLH
area in the afternoon/early evening hours. Otherwise light winds
from the northeast elsewhere. An area of low pres is expected to
track ne into the Great Lakes region late Mon/Tue. This system will
bring northerly winds of at least 15-25kt with gusts to 30kt.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Beachler
LONG TERM...Rolfson
AVIATION...Titus
MARINE...Beachler
Office: DTX
FXUS63 KDTX 180358
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 PM EDT Fri Aug 17 2018
.AVIATION...
Wind directions have uniformly turned to the northwest or west in
all location which has begun the drying out process of the
atmosphere. Plan view progs suggest a slow drying response this
evening, increasing now after 06Z. Deep downward motion is
forecasted with building surface high pressure. However, subsidence
inversion is not overly impressive and some diurnal instability will
exist Saturday afternoon. Model trends are now suggesting some
greater static stability in the midlevels. Dry conditions
anticipated today.
.DTW THRESHOLD PROBABILITIES...
* Low for cigs aob 5kft overnight, medium Sat afternoon.
&&
.PREV DISCUSSION...
Issued at 338 PM EDT Fri Aug 17 2018
DISCUSSION...
Extensive cloud cover remains in place over the area as the upper
low near Chicago slowly makes its way east. Clearing over northern
IN and southwest Lower MI has fostered modest destabilization and
subsequently allowed showers and thunderstorms to develop in that
area. This activity will spread into the the Detroit Metro area and
points south and west into the evening as renewed warm and moist
advection lifts into the area and larger scale dynamic forcing
increases. In the meantime, mediocre convection will likely continue
to flare up at times within areas of enhanced boundary layer
convergence. Further north, more organized mesoscale forcing will
still pose a threat for locally persistent heavy rain. However, the
lack of destabilization to this point, HRRR analysis indicates just
a few hundred J/KG MLCAPE, suggests the outcomes indicated by the
12z suite are highly unlikely. Instead, maintained likely to
categorical pops and will simply highlight a locally heavy rain
threat potentially leading to poor drainage or urban flooding.
Little in the way of airmass change between now and Sunday as H850
temps hover in the mid teens within mean troughing regime. Scouring
out of today's moisture will limit convective potential,
particularly as mid-level temperatures warm, favoring just diurnal
cu-up Sat and Sun aftn as high temps settle in the low 80s with a
decent coverage of upper atmosphere smoke worthy of an upward nudge
in the sky grid.
Midlevel ridging will remain in place on Monday as surface high
pressure drifts northeast into New England, allowing for a dry
Monday morning and afternoon for our area. Highs near normal in the
lower 80s and light southeasterly winds expected. A shortwave
currently moving over the Pacific Northwest will make its way into
the central Plains by this weekend and interact with additional
upper energy dropping in from the Canadian Prairie provinces on
Tuesday, resulting in a strengthening mid-latitude cyclone moving
into the Great Lakes by late Monday night. Long range guidance has
begun to converge on a solution suggesting the center will track
through lower Michigan during the day Tuesday. Chance for showers
and thunderstorms increases Monday evening and lasts through the day
Tuesday.
A broad area of high pressure will build back in on Wednesday and
maintain influence over the area through the rest of the work week,
allowing quiet weather to prevail. The early week system will pull a
good amount of cooler and drier air southward from Canada, leading
to highs in the mid to upper 70s Tuesday through the end of the week.
MARINE...
A weak secondary area of low pressure tracking across Lower Michigan
will maintain showers and thunderstorms this evening before exiting
the region tonight. In its wake, weak high pressure will build
across the Great Lakes bring dry weather for the weekend. Light to
moderate northerly flow will prevail through the weekend, with peak
gusts limited to around 15 knots.
HYDROLOGY...
A secondary low pressure system moving across Lower Michigan will
bring scattered to numerous showers and thunderstorms through this
evening. Rainfall amounts will generally range from a quarter to a
half of an inch, with locally higher amounts associated with
thunderstorms. The flooding threat will be minimal, with ponding of
water on roadways and localized minor poor drainage flooding briefly
possible where the heaviest rainfall occurs. Outside of an isolated
shower Saturday afternoon, the weekend will feature dry weather with
weak high pressure building across the region.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....CB
DISCUSSION...JVC/TF
MARINE.......JD
HYDROLOGY....JD
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Office: APX
FXUS63 KAPX 180350
AFDAPX
Area Forecast Discussion
National Weather Service Gaylord MI
1150 PM EDT Fri Aug 17 2018
.UPDATE...
Issued at 957 PM EDT Fri Aug 17 2018
Last of the diurnal convection (near and s of W Branch) has faded
out over the last hour. Maybe a small shower can still fire for
another hour or so, but otherwise we are mostly done with precip
for the night. Most recent Rap run does pop a few showers over
Saginaw Bay toward morning, perhaps due to converging land
breezes. This does not require a mention of shower, at least over
land.
Have expanded the mention of fog across all of northern MI
overnight. Airmass remains plenty soupy (especially in northern
lower), and cloud cover is exiting east (though we might have
enough smoke overhead to inhibit cooling to some degree).
No big changes to temps.
&&
.NEAR TERM...(Through Tonight)
Issued at 340 PM EDT Fri Aug 17 2018
...Showers and Thunderstorms Into the Evening...
High Impact Weather Potential: Thunderstorms through early evening.
Mostly non-severe, although a stronger storm/updraft could produce
hail...along with heavy rain.
Pattern Synopsis/Forecast: Slow moving closed low is over
Chicago/southern Lake Michigan, associated broad surface low
pressure is across far southern Ontario. Showers and some
thunderstorms with this system continue across central lower
Michigan back into Wisconsin within the associated deformation
axis, just skirting our far southern counties.
Further north, lots of mid/high cloud cover has spread up into
northern lower Michigan, mainly south of M-32. SPC mesoanalysis
reveals in excess of 500 J/KG MLCAPE across the southern counties.
Some convection is now developing along the differential heating
boundary that bisects northern lower MI currently. Strongest
updrafts so far (supporting some elevated hail cores in the last
hour) have been (of all places) in Benzie/Manistee counties,
where the intersection of the Lake Michigan marine boundary has
helped.
Tonight: Closed mid-level circulation over the Chicago area still
expected to open up and advance through lower Michigan through
this evening. Band of showers/thunder associated with attending
deformation axis will largely stay to our south, clipping the
Gladwin/Arenac counties area.
Meanwhile to the north, as noted, convection has started along
the differential heating boundary that bisects northern lower
Michigan and will likely continue to percolate/meander across
northern lower Michigan over the next few hours before diminishing
this evening. Always tough to know exactly how convection will
ultimately unfold. But I suspect the bulk of showers/storms will
tend to contract inland and south over the next few hours.
Severe weather potential: Relatively light winds aloft, minimal
ambient shear, and higher freezing levels suggest a low severe
storm threat. But, as we've seen, strongest updrafts can support
marginally severe hail. And, slow moving/back building updrafts
will result in localized heavy rain. Will mention those in the
HWO.
&&
.SHORT TERM...(Saturday through Monday)
Issued at 340 PM EDT Fri Aug 17 2018
Saturday through Sunday
...Despite the Small Rain Chances Saturday the next Round of Dryness
Begins...
High Impact Weather Potential...Thunderstorms, but nothing severe
expected.
Pattern Synopsis/Forecast...Models then begin to show another
"wiggle" in the 500 mb height fields for rain to be possible, but it
looks a lot less impressive than today's convection, and yesterday's
convection. Things diminish quickly by the evening and dry out
overnight. On Sunday, the high is built into the region, drying out
the state. The high continues over the region through the night.
Primary Forecast Concerns...Again is the thunder potential on
Saturday, Most of the models are pegging the area near M-55 and I-75
as where the convection would occur. While the consensus is in that
area, the ECMWF and the GFS have a broader coverage to the
convection Saturday. So, there is a lower chance that it will be
over portions of N Lower.
.LONG TERM...(Monday night through Friday)
Issued at 340 PM EDT Fri Aug 17 2018
...Rain on Monday night/Tuesday then Pretty Much Dry through
Friday...
Extended (Monday through Friday)...The ridge breaks down Monday,
allowing a cold front and the 500 mb low trough to move into the
region. It looks like thunder will be possible as the cold front
moves into the area Monday night/Tuesday morning. Then the models
show a decent band of rain on the north side of the sfc low in a
deformation zone producing some rain, possibly heavy at times, as
the system move NE through the State. Will continue the cautious
optimism as the models are holding onto this feature, but details
are still a little less certain. As the GEFS plumes show the mean
over GLR just under 0.5", but the GFS model, itself showing 1.4" and
is the furtherest outlier. However, the latest ECMWF is also showing
over an 1" of rain in Gaylord, as well. So it looks like a good
soaker, but not sure about the heavy amounts that the deterministic
models are trying to produce. Wednesday through Thursday are dry,
then scattered rain on Friday so low chance pops there.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1150 PM EDT Fri Aug 17 2018
Some fog again overnight, otherwise VFR.
Still expecting some fog overnight, with similar conditions to
last night progged (IFR at times PLN, MVFR MBL/APN, no issues at
TVC). Airmass remains muggy, and though some smoke aloft will
limit cooling, ground fog is still expected. Additional showers/
storms will fire Saturday afternoon in some interior sections of
northern lower MI, but these should be inland from all of the TAF
sites.
Light northerly breezes.
&&
.MARINE...
Issued at 340 PM EDT Fri Aug 17 2018
Lighter winds and waves will continue to dominate over the next
few days. No marine headlines anticipated.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JZ
NEAR TERM...BA
SHORT TERM...JL
LONG TERM...JL
AVIATION...JZ
MARINE...BA
Office: GRR
FXUS63 KGRR 180359
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
1159 PM EDT Fri Aug 17 2018
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 330 PM EDT Fri Aug 17 2018
Low pressure passing across southern Lower Michigan this evening
will bring scattered showers and thunderstorms, some containing
torrential downpours. The showers will end overnight, then a
mainly dry and warm weekend is expected.
A significant storm by August standards will pass through the
Great Lakes Region Monday night and Tuesday, bringing widespread
rain and thunderstorms followed by windy conditions. Dry, cooler,
and comfortable late summer weather will follow behind that
system for the rest of next week.
&&
.UPDATE...
Issued at 1008 PM EDT Fri Aug 17 2018
Showers have all but ended across the forecast area at 1000pm. An
isolated shower will remain possible for another hour or two from
roughly I-96 to the south, but for the most part expecting dry
conditions.
Next question will be cloud cover, which is more widespread across
the south at this time. The cloud cover in the south is directly
related to the upper trough being situated across that area. In
general expect clouds to decrease even across the south, at least
initially. The concern is that as the cloud associated with the
upper trough begin to push south we develop stratus in a cooling
but moist boundary layer. Hi-res models are becoming more bullish
on low clouds filling in from AZO to LAN and points to the east of
that line. Patchy fog is also expected as the surface winds will
be light through the night.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 330 PM EDT Fri Aug 17 2018
Combination of the upper low tracking through this evening and
very moist air mass with PWATs around 1.7 inches will result in
a continuation of showers and tstms with torrential rain. The
showers will be very slow movers so a localized flooding risk
will exist over the next several hours as diurnal heating cycle
peaks. Hard to nail down where best threat of flooding may be,
although latest radar trends and HRRR suggest one area along/near
I-94 and another from roughly Ionia to Flint.
System moving out overnight so showers ending with decreasing
clouds from northwest to southeast. The north flow behind the
system is rather weak so doubt that the current dew points near
70 will drop off much overnight. That may lead to areas of fog
developing again as skies clear, particularly where heavy rain
occurs through 10 PM.
On Saturday full sun is not expected. The combination of diurnal
cumulus clouds and a relatively thick smoke layer aloft should
lead to a partly cloudy/hazy sunshine type of day. Isolated
afternoon/early evening showers cannot be completely ruled out on
Saturday. Less risk of diurnal clouds and isolated showers on
Sunday, although some smoke may still be present aloft.
.LONG TERM...(Monday through Friday)
Issued at 330 PM EDT Fri Aug 17 2018
Confidence continues to increase that a deepening sfc low
will be tracking through the area on Monday night and Tuesday.
Impacts will be widespread much needed rain then windy
conditions as the low pulls away. A severe weather threat may
develop Tuesday as the sfc cold front comes through, but timing
of things and specifics still uncertain. Deep layer shear of
around 35 kts is progged, although amount of instability unclear
given expected high coverage of clouds/precip. This will be
something to watch in the coming days. Regardless of cold frontal
timing, marine impacts should be significant in the strong NW flow
and cold advection behind the front Tuesday afternoon and Tuesday
night. Weather then turns quiet for mid to late week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1153 PM EDT Fri Aug 17 2018
A mix of VFR/MVFR conditions at the moment will gradually
deteriorate to primarily MVFR during the early morning hours
Saturday due to development of low clouds and patchy fog. Some
patchy IFR is also possible early Saturday morning due to
potential for some locally denser fog and/or low clouds.
Conditions will gradually improve to mainly VFR by mid to late
Saturday morning as patchy fog dissipates. VFR conditions will
then continue at all the terminals Saturday afternoon through
Saturday evening.
&&
.MARINE...
Issued at 330 PM EDT Fri Aug 17 2018
North-northwest flow over Lk MI looks to be remaining on the
lighter side this afternoon, although it could be briefly
stronger on Saturday from mid afternoon through early evening
resulting a some choppier conditions for a time. Sunday looks like
a tranquil day on the lake, and the winds on Monday should be
mostly offshore. However hazardous winds are waves are a good bet
on Tuesday into Tuesday night as deepening sfc low tracks through.
Small Craft Advisories and Beach Hazard Statements will likely be
needed, and gales/beach erosion are not out of the question
either.
&&
.HYDROLOGY...
Issued at 154 PM EDT Fri Aug 17 2018
Rainfall over the past 24 hours...per MRMS with gage correction...
has been more widespread than in recent days...with locations south
of Grand Rapids showing one tenth of an inch or less. More isolated
coverage of rainfall was indicated over northern sections of Central
Lower Michigan...with some amounts in excess of one inch. The low
amounts to the south and the isolated nature of the heavy rain to
the north have produced little to no impact to area river levels.
Heavy rain of 4 to 6 inches fell across east central Wisconsin since
Thursday morning.
Quite a bit of uncertainty as to the expected coverage and location
of rainfall this afternoon and evening. Atmosphere has plenty of
moisture to work with as precipitable water values in excess of 1.5
inches over most of Lower Michigan. Slow movement of showers and
thunderstorms will also aid in producing increased amounts in areas
that receive rainfall.
Threat for significant impacts to area rivers is highly conditional
over the next 48 hours...mainly due to the recent dry conditions.
If precipitation can develop over a basin with appreciable areal
coverage and persist long enough for significant runoff to
develop...river stages could show significant rises. Combination of
factors results in a low confidence forecast for river impacts over
the next 48 hours.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...Duke
SYNOPSIS...Meade
SHORT TERM...Meade
LONG TERM...Meade
AVIATION...Laurens
HYDROLOGY...MWS
MARINE...Meade
