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Office: MQT

FXUS63 KMQT 211136

Area Forecast Discussion
National Weather Service Marquette MI
736 AM EDT Mon May 21 2018

.SHORT TERM...(Today and tonight)
Issued at 439 AM EDT MON MAY 21 2018

Water vapor imagery and RAP analysis show a deep northern stream
trof over eastern Canada. The flow is split over western N America
with a ridge over western Canada and a trof over the western CONUS.
In the sw flow downstream of the trof, a couple of shortwaves are
over the central Plains. One of the fcst concerns during the short
term will be whether these shortwaves will spread any shra into the
fcst area late today or this evening. Prior to that, fire wx will be
a concern. Currently, skies are clear across the fcst area, though
some high thin clouds are beginning to spread out of WI into Upper
MI ahead of the aforementioned shortwaves. A wide range of temps is
noted with some interior locations down in the low/mid 30s while
temps are as high as the low/mid 50s at some locations near Lake
Superior. Warmest conditions are in the Marquette area.

Some high clouds, mostly thin, will spread across the area today.
Mid clouds should then follow into s central Upper MI during the mid
and late aftn hrs as upstream shortwaves move closer. With high
clouds not providing much restriction to solar insolation, deep
mixing of drier air down from aloft will lead to another day of low
RH. Similar to yesterday, incorporated lower dwpts based on mixing
heights along with bias corrected guidance to arrive at aftn dwpts.
With high temps rising well into the 70s, min RH will likely be in
the 17 to 25pct range for much of the fcst area. Sustained winds
should be up around 9-13mph with gusts in the 15-20mph range,
strongest over the central fcst area. As a result, wildfire
potential will be elevated sufficiently to warrant a special weather
statement to heighten awareness for much of the area today,
particularly the central counties where winds will be strongest.
Under se winds, coolest conditions this aftn will be along Lake MI
and the east side of the Keweenaw.

Shortwave will weaken/shear e across the Great Lakes region tonight
in the more confluent flow across this region. As a result, moisture
transport gets shunted eastward rather than northward into Upper MI.
So, shra potential looks quite limited. As with the late aftn hrs,
will only include shc shra mention across southern Menominee County
this evening. Otherwise, with more cloud cover around tonight,
bumped min temps up a few degrees from previous fcst. 40s will be
the rule.

.LONG TERM...(Tuesday through Sunday)
Issued at 417 AM EDT MON MAY 21 2018

Dry with a warming trend to start the extended then still looks like
pattern could become more unsettled with increasing chances of rain
late this week into the holiday weekend as upper level trough
starting this week over the southwest CONUS moves to the northern
Plains and eventually the Upper Great Lakes. Initially Tue, Wed and
possibly into Thu focus will remain on fire weather concerns. Min RH
values should be 20-30 pct as daytime temps inland reach the 70s
Tue, well into the 80s over the interior west half on Wed and maybe
into the lower 80s on Thu depending on cloud cover. High pressure
ridge persisting will result in lake breezes Tue and Wed with gusts
inland reaching 15 mph. Later Thu, initial push of stronger moisture
advection could support some showers trying to move into western
Upper Michigan. Soundings indicate weak forcing and good deal of dry
air to overcome in low-levels so not expecting much rain on Thu. At
the least, clouds should thicken up over the west through the day.

Attn Thu night into Fri will be on shortwave trough and sfc low
slowly crossing the northern Plains and extending into scntrl
Canada. With the sfc low well to the northwest of here, increasing
south to southwest flow should result in increasing instability into
the Upper Great Lakes. Late Thu into Fri, Upper Great Lakes will be
on edge of elevated mixed layer with mid-level lapse rates over
7C/km. Would expect t-storm potential during this time to be driven
by where strongest moisture transport develops and also by any
convectively induced shortwaves that emerge from t-storms over the
northern Plains to the Upper Mississippi River Valley. With the
increasing instability could also see t-storms develop along lake
breezes over especially western and central Upper Michigan. MLCAPE
to 1000j/kg seems possible on Fri as sfc dwpnts climb into the 50s
to near 60F. Admittedly early to pin down shear forecasts, but
models are giving around 30-35 kts at this time. Seems that there
could be some stronger storms Fri if these forecasts of instability
and shear continue to hold. Main upper trough moves through in
northwest flow on Sat as sfc low crosses north of Lk Superior
swinging a cold front across Upper Michigan. Should see decent
coverage of showers and t-storms on Sat, though is is possible
chance of stronger storms could be held down as plume of steeper
lapse rates and greatest instability may advect farther south and
east by that time as low-level jet veers to the west.

Will keep chance of showers going Sat night into Sun until upper
trough axis exits east of Upper Michigan. Though most of the weekend
will be unsettled, good agreement that high pressure building back
over the region will bring dry weather for Memorial Day. Gone today
is the idea of cooler air plowing in over the region as well so
could be pretty warm Memorial Day, especially inland away from
Great Lakes.

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 736 AM EDT MON MAY 21 2018

With high pressure and a dry air mass lingering, VFR conditions will
prevail at KIWD/KCMX/KSAW through this forecast period. Light winds
will increase some today, especially at KSAW where gusts to
around 17kt are expected in the aftn.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 439 AM EDT MON MAY 21 2018

A weak pres gradient will dominate for much of this week, leading to
winds less than 20kt across Lake Superior. On most days, winds will
be under 15kt across much of the lake. A low pres system or trough
moving across the western Great Lakes on Sat may lead to somewhat
stronger winds at some point Fri/Sat.

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


SHORT TERM...Rolfson

Office: DTX FXUS63 KDTX 211706 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 106 PM EDT Mon May 21 2018 .AVIATION... Low pressure tracking east over northern Illinois will bring a gradual increase in moisture to the area through the remainder of the afternoon. Radar imagery shows a region of rainfall and a few thunderstorms associated with this low that high-res guidance indicates will track eastward across all terminals after 19Z. As the rainfall overspreads the area, expect lowering ceilings and easterly winds through the late afternoon before MVFR ceilings develop during the evening. The best potential for isolated thunderstorms appears to be focused during the late evening for the Metro Detroit terminals from PTK southward where instability will increase with southward extent. As the low tracks into the area overnight, increasing low level moisture will bring low MVFR/IFR ceilings and visibilities across much of the region as showers continue through early Tuesday morning. Some improvement is then expected by late Tuesday morning as the low tracks westward and ceilings rise back to MVFR under lingering low level moisture. For DTW...Light to moderate rainfall is expected to overspread the terminal after 19Z and continue through 00Z. Elevated instability will then increase ahead of the low during the evening bringing the potential for isolated thunderstorms during the late evening and continuing into the overnight. Increasing low level moisture as the low approaches will cause ceilings and visibilities to fall to low MVFR/IFR late tonight before improving Tuesday morning. .DTW THRESHOLD PROBABILITIES... * Moderate in ceilings at or below 5000 late this afternoon. High tonight. * Moderate in thunderstorms impacting the airport late this evening. && .PREV DISCUSSION... Issued at 1010 AM EDT Mon May 21 2018 UPDATE... As of 1010 AM EDT...Ongoing forecast continues to be on track, and have made some tweaks to PoPs for today based on the latest trends in hi-res guidance that slows onset, but a little more widespread in coverage mid-late afternoon. Locally dense fog that occurred this morning in the Tri-Cities region and portions of the Thumb has all but dissipated as morning heating continues. Cloud cover continues to increase out ahead of a decaying MCS currently moving into lower Lake Michigan. A few streamer showers east of this feature have attempted to move into lower Michigan, but stronger than anticipated surface high pressure and associated low-level dry air will preclude any of this precipitation from reaching the ground. It will take the remainder of the morning hours to saturate the column as the MCS approaches. Onset of showers now looks to be in the 2-4 PM timeframe west of US 23/I-75, and mid/late afternoon across the rest of southeast Michigan. Surface-based instability will be limited as lower Michigan will reside on the northern side of low pressure approaching from northern Illinois/Indiana. There will be some elevated instability moving in however and cannot rule out embedded thunder. Where thunderstorms and heavier showers occur, downpours will be possible with ponding of water on roadways and possible poor drainage flooding. Temperatures will only make it into the 60s early this afternoon, then gradually fall towards evening into the upper 50s/lower 60s with thick cloud cover and rain-cooled air. Dewpoints rising into the 50s will lead to abundant near surface moisture, and with easterly flow advecting additional moisture off Lakes Erie, St. Clair, and southern Huron, have added patchy fog to the forecast for general reduced visibilities late this afternoon and through the evening. Continue to also closely monitor lakeshore flooding potential with developing moderate easterly flow this afternoon and evening for the shores of western Lake Erie. PREV DISCUSSION... Issued at 300 AM EDT Mon May 21 2018 DISCUSSION... A wet start to the week as two distant upper waves tracks through Lower Michigan. The first wave will exit the midwest and reach southern Lake Michigan by early evening, sending a good deal of moisture into the State as 850 MB dew pts push toward 13 C (per 00z NAM), with low pressure tracking along the southern Michigan border this evening providing the focus for rainfall. Being on the north side of the low, no surface based instability to speak off, but the showalter index does go slightly negative (mainly along/south of M- 59) with strong low level jet working through, so chance/scattered thunderstorms appear fine, which will only act to enhance rainfall. Detroit will easily surge into the top 10 wettest May's on record, as the climo site currently sits at 5.60 inches/11th place. Cool start this morning, light easterly flow, coupled with clouds thickening up and rain showers arriving later in the day should hold high temps in the 60s. Trailing upper wave over central Plains to track through northern Lower Michigan Tuesday morning, which may allow for a few more showers, but mid level dry slot look to encompass much of the CWA during the day, before low level convergence/secondary cold front slips south of the border. Pronounced upper level northwest confluent flow Tuesday night will allow surface high (1020 MB) to build over Central Great Lakes. Could be enough surface/near surface moisture to support radiation fog. Upper level ridge axis over the Mississippi River Valley will slide east for the end of the work week, allowing for a significant warmup (80s). However, the warm front lifting through could become active, and derail the temperature climb if it gets hung up. Upper level low/trough coming out of the northern Rockies looks to be moving through the Great Lakes region over the Weekend, potentially bringing unsettled conditions with a good chance of showers and thunderstorms, but the amount of moisture around will need to be sorted out. MARINE... High pressure will remain across Lake Huron today, generally supporting light and variable winds. A frontal boundary located across the Ohio Valley will lift north as a warm front into Southern Michigan and Lake Erie tonight. Numerous waves of low pressure will track along this front, crossing the southern lakes region tonight and Tuesday. There will be an enhancement to the easterly winds on Lake Erie today. At this point, winds and waves are expected to hold below small craft conditions. The winds on Lake Erie will become more variable tonight with the passage of the sfc low. There will however be a developing northeasterly gradient on southern Lake Huron tonight, which will persist into Tuesday, as low pressure systems slide across the southern Great Lakes. At this point, the gradient is not expected to be strong enough to warrant small craft conditions. High pressure will expand back across the Great Lakes by Wednesday, resulting in light winds. HYDROLOGY... Showers will overspread southeast Michigan late this afternoon and will be widespread this evening, tapering off overnight. Rainfall totals around half an inch are expected across most locations, but a few thunderstorms are also likely, especially south of I-69, which will tend to enhance the rainfall, sending isolated amounts around an inch, which could lead to poor drainage flooding of low lying and urban areas. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....JD UPDATE.......IRL DISCUSSION...SF MARINE.......SC HYDROLOGY....SF You can obtain your latest National Weather Service forecasts online at
Office: APX FXUS63 KAPX 211536 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1136 AM EDT Mon May 21 2018 .UPDATE... Issued at 1126 AM EDT Mon May 21 2018 Convectively augmented wave and attendant moisture plume continue to pinwheel a rather large area of showers northeast into the lower Great Lakes this morning. These will continue to advance northeast, running into a much drier airmass in the process. Still think rain will reach the surface this afternoon and evening, especially south of M-32. Rain amounts should be light, with any thunder threat transitioning further south and out of our area. Forecast has been trended to a bit more temporal and spatial detail with regards to these showers. Otherwise, overall flavor of the inherited forecast remains unchanged. && .NEAR TERM...(Tonight) Issued at 153 AM EDT Mon May 21 2018 Impactful weather: Minimal. Low afternoon humidities. Pattern synopsis and forecast: Nrn Michigan remains in a confluent upper level flow, with NW mid level winds coming out of Ontario and more W/WSW winds coming out of a weak/shallow shortwave in the central conus. There was virtually no forcing out there attm, with sfc high pressure overhead and light/calm winds. Temperatures were chilly, but not quite as chilly as what was expected yesterday at this time. Dew points didn't mix out as effectively yesterday, likely due to the greater amount of green up that's been underway. This was especially the case along and south of M-72 where areas of fog have also developed. With the great radiational cooling conditions right now, am still expecting many areas along and north of M-72 to get chilly enough for frost/some fog development. There was some shower activity ahead of the weak shortwave, from far srn MN through Iowa/MO/IL. This was in a zone of weak forcing comprised of DPVA, low to mid level WAA and some upper divergence from a rather meager 60+kt upper jetlet. Heading through daybreak, higher level clouds with the aforementioned shortwave will start streaming in over the srn CWA, thickening up into a mostly cloudy/cloudy sky by late morning/early afternoon across much of nrn lower Michigan. Eastern upper to see a good deal of sun through much of the day. High temperatures will be warmest across the U.P. ... in the lower half of the 70s, decreasing heading further south (into the upper half of the 60s) where thicker clouds prevent as much solar insolation. Could even see some light rains develop as early as this afternoon in the GTV Bay region and along/south of M-72, as the weak forcing to our west attm, moves in across this area. This forcing and deepening moisture then crosses mainly M-32 and south in nrn lower through the night, providing chances for rain. No instability will result in little to no chance of thunder. The sfc high pressure and drier air remains over eastern upper through tonight, with little to no chance of any rain. Lows tonight have been raised a couple degrees in the srn half of the CWA with respect to consensus MOS numbers, due to thick low level cloud. Readings in the middle 40s north to as mild as the lower 50s to the M-55 corridor expected. && .SHORT TERM...(Tuesday through Wednesday) Issued at 153 AM EDT Mon May 21 2018 ...Quiet & warm midweek weather... High Impact Weather Potential: Minimal, although may have to watch fire danger concerns toward the middle of the week. Pattern Forecast: Rather zonal flow aloft will encompass the midsection of the country through much of the forecast area. A couple of weak shortwaves are expected to race across the region early Tuesday and again late Wednesday, but with little fanfare as strong surface high pressure drives northern Michigan's sensible weather through at least Thursday. Primary Forecast Concerns/Challenges: Temperatures and minimum relative humidity related to fire weather concerns, primarily on Wednesday. An area of low pressure passing through southern Michigan/Ohio valley Monday night will continue to shift east early Tuesday morning. Aside from a rogue lingering shower early in the day (primarily east of I-75), clearing skies will be the rule. Mostly sunny skies expected area-wide by mid-late afternoon as high pressure sits atop the region. High temperatures expected to top out in upper 60s to low 70s across the forecast area (cooler along the immediate lake shores). Quiet weather expected to continue into Wednesday with lots of sunshine and temperatures climbing a few degrees over Tuesday's highs. Low-mid 70s expected across eastern upper and low 70s to low 80s across northern lower. With high pressure continuing to remain in control, lots of dry air is expected through the column represented by afternoon minimum relative humidity values falling to the 20-35% range across the majority of the forecast area...lowest in sections of northeast lower. Despite light winds, the combination of warm temperatures and low RH will likely raise concern for elevated fire danger once again. .LONG TERM...(Wednesday night through Sunday) Issued at 153 AM EDT Mon May 21 2018 High Impact Weather Potential: Minimal. High pressure continues over the Great Lakes region producing a quiet, warm, and dry Thursday. By late in the week, an area of low pressure is expected to be dropping out of Canada into the northern plains before sliding east across the Great Lakes this weekend. With accompanying moisture advection from the Gulf of Mexico, shower and perhaps occasional thunderstorm chances return to the forecast as early as Thursday night/Friday and continue at various times through at least Sunday. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) Issued at 623 AM EDT Mon May 21 2018 ...MVFR CIGS and possible light rains developing at TVC/MBL... High pressure will be entrenched across eastern upper, while a weak area of low pressure crosses to our south tonight. Clouds will thicken from aloft heading through the day and evening, especially TVC/MBL, where light rain showers are possible this afternoon and into tonight. Also, MVFR CIGS are expected there tonight and through much of Tuesday. ATTM, not expecting and reductions in VSBY in the showers, outside of something brief in a potential brief heavier shower. Light winds through the period. && .MARINE... Issued at 153 AM EDT Mon May 21 2018 A weak pressure gradient will hold over the region for the next several days, resulting in minimal chances for any wind/wave issues. Weak low pressure does cross srn Lakes Michigan and Huron later this afternoon into tonight for some potential light rain showers. Otherwise, next chance of rain arriving mainly Friday-Saturday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...MB NEAR TERM...SMD SHORT TERM...MG LONG TERM...MG AVIATION...SMD MARINE...SMD
Office: GRR FXUS63 KGRR 211522 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 1122 AM EDT Mon May 21 2018 LATEST UPDATE... Update .SYNOPSIS... Issued at 330 AM EDT Mon May 21 2018 Low pressure moving northeast from Missouri will bring widespread rain and cool temperatures today and tonight. Clouds will linger in the wake of this system on Tuesday then sunny and warm weather is expected Wednesday and Thursday. Memorial Day Weekend starts out warm and humid with scattered showers and thunderstorms, then ends up dry for the holiday. && .UPDATE... Issued at 1122 AM EDT Mon May 21 2018 Rain is overspreading the area from the southwest, with embedded thunderstorms expected to stay mainly south of I-94. Evaporative cooling is expected with rain falling into surface air with dewpoints in the 40s and 50s, which will keep temperatures in the upper 50s to lower 60s for much of the day. Mid-level moisture convergence will depart this evening allowing for a break in the rain. MUCAPE values around 500 J/kg from parcels between 925 and 850 mb are still expected overnight as the main upper level trough approaches. Scattered thunderstorms may develop then, mainly near/south of I-96. Severe potential appears to be quite low due to cold and stable air at the surface. && .SHORT TERM...(Today through Wednesday) Issued at 330 AM EDT Mon May 21 2018 Big slug of rain headed our way today as shortwave ejects northeast from the Plains and draws up PWATs over 1.5 inches via 30kt low level jet. Will have categorical pops spreading in from southwest to northeast this morning, then expect a persistent cool rain this afternoon and evening which could even be heavy at times once the higher h8 theta-e air arrives from the south. Widespread rainfall amounts of one half to one inch are expected, although some streaks of locally heavier amounts over an inch are quite possible. MUCape progs argue against much coverage of tstms this afternoon and evening, but will continue to carry a slgt chance as some weak elevated instability does come through later in the day and evening. Heaviest/widespread rain departs after midnight, put expect some lingering scattered showers and areas of drizzle/fog. Low clouds will linger most of the day Tuesday, although some clearing may develop later in the day especially over nrn and wrn sections. Prospects for sunshine are much better on Wednesday (after patchy morning stratus/fog dissipates) with drier air mass and sfc ridge overhead. .LONG TERM...(Wednesday night through Sunday) Issued at 330 AM EDT Mon May 21 2018 Chances for rain aren't great during the long term, but probably highest over the northwest cwa. Initially, high pressure over Michigan will drift east late Thursday. Developing low pressure over the Plains will generate showers/storms along the Mississippi valley as the LLJ strengthens. An upper trough moving across the northern tier of states will push the sfc low eastward and the precipitation ahead of it will move toward the cwa. The highest chance of precipitation looks to be late Saturday as the trailing cold front moves across the cwa, but pops will linger into Sunday as the upper support moves through. Highs through the period will be in the 76 to 81 range. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) Issued at 754 AM EDT Mon May 21 2018 Variable flight conditions exist this morning, ranging from VFR to IFR/LIFR where areas of fog/stratus are present. Conditions will trend toward predominately MVFR by afternoon everywhere as rain becomes more widespread, then mostly IFR by later in the day and this evening as the rain continues and is occasionally heavy. Late tonight there will probably be quite a bit of LIFR developing as cigs further lower and areas of fog/drizzle develop behind the departing area of heavier rain. && .MARINE... Issued at 330 AM EDT Mon May 21 2018 May be dealing with areas of fog over Lake Michigan over the next 48 hours before high pressure delivers a drier air mass on Wednesday. Otherwise winds and waves expected to remain below advisory criteria. && .HYDROLOGY... Issued at 1127 AM EDT Sun May 20 2018 Many rivers especially in southern Michigan are running much above normal for this time of year, with lowland nuisance flooding still occurring at several points. Most river levels are falling. Showers on Monday have the potential to produce around a half inch of rain on average in southern Michigan, though it wouldn't be surprising if some locations picked up closer to an inch. Depending on the basins where any heavier rain may fall, this could prolong the nuisance flooding. The middle part of the week will be dry, then rain chances return toward the end of the week. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...CAS SYNOPSIS...Meade SHORT TERM...Meade LONG TERM...04 AVIATION...Meade HYDROLOGY...CAS MARINE...Meade