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Office: MQT

FXUS63 KMQT 172349

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

.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.

Upper Michigan...
Lake Superior...
Lake Michigan...


SHORT TERM...Beachler
LONG TERM...Rolfson

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
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