Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 150148
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
948 PM EDT Mon Aug 14 2017

.UPDATE...
Issued at 945 PM EDT Mon Aug 14 2017

Earlier diurnally enhanced showers and thunderstorms have now
pushed off into Lake Huron. Additional lighter showers rotating
east/southeast back across Wisconsin, tied to mid level wave
itself. This feature will slide across the area overnight,
bringing some of those light showers along with it. Not a lot of
rain for sure, and very possible many stay dry for the remainder
of the night. Plenty of clouds yet to pass overhead, which will
result in milder temperatures than those observed the last few
nights.

&&

.NEAR TERM...(Tonight through Tuesday)
Issued at 348 PM EDT Mon Aug 14 2017

...Convection continues this evening then diminishes...

High impact weather potential...t-storms thru this evening, few
strong storms possible.

Reasonably vigorous/widespread convection continues in ne lower MI,
away from the Lake MI shadow. Some weaker, residual showers are
occurring in eastern upper MI, as well as pushing into w central
lower MI. This activity is occurring in advance of a pair of
shortwaves digging toward Superior and central WI. Instability will
of course fade out by the time these waves cross northern MI
overnight, but the incoming upper trof will fight that trend off for
a while. Still looking at pretty quiet wx for Tuesday.

Ongoing activity in ne lower should remain reasonably robust this
evening, though expect intensity and eventually coverage to trend
downward after 7 pm. Have had a few cells get to the point of being
a hail/gusty wind producer; an isolated svr cell isn`t completely
out of question, but we have neither the shear nor instabilty for
anything resembling an outbreak (per AFDs from earlier today).

Even as ne lower activity diminishes, the incoming upper trof will
help some residual showers move from WI into parts of nw lower MI
and perhaps. Given very meager instability (but moderate forcing),
only light precip expected. By late in the overnight, only expect a
few lingering showers from CAD to OSC and points south.

High pressure will build toward Superior on Tuesday. Northerly low-
level flow in advance of this high will push slightly cooler/drier
low-level air into the region. Warmer temps aloft will also limit
attempts to build instability on Tuesday. Skies will tend to clear
from nw to se during the morning, resulting in a quiet and pleasant
day.

Min temps in the 50s. Max temps mid 70s to around 80f, cooler on
some of the beaches.

&&

.SHORT TERM...(Tuesday night through Thursday)
Issued at 348 PM EDT Mon Aug 14 2017

...Widespread rain possible Wednesday night-Thursday...

High Impact Weather Potential: Chance of thunderstorms Wednesday
night through Thursday. Periods of heavy rain also possible during
the same time frame.

Pattern Forecast: By Tuesday night, surface high pressure and rising
heights/ridging aloft are expected to be the dominant feature across
the midsection of the country ahead of an intensifying shortwave and
attendant area of low pressure ejecting eastward from the
Intermountain West...set to plague the Great Lakes Wednesday night-
Thursday.

Primary Forecast Concerns/Challenges: Focus revolves around
Wednesday night-Thursday`s heavy rain/thunder potential.

After a relatively quiet Tuesday night and Wednesday with high
pressure overhead, changes are expected to get underway Wednesday
evening. Low pressure across the upper Mississippi Valley Wednesday
afternoon continues to deepen as it slowly progresses northeastward
Wednesday evening. Locally, warm air advection will be underway
through most of the day, but really ramps up late Wednesday
afternoon through Wednesday evening. As a result, increasing deep
layer moisture and top-down saturation will lead to increasing
shower chances (and perhaps a few thunderstorms) from southwest to
northeast Wednesday evening through Wednesday night. At this
juncture, the greatest thunder threat arrives very late Wednesday
night through midday Thursday as northern Michigan lies squarely in
the warm sector. Forecast model soundings suggest a north-south
oriented instability gradient with a couple hundred J/kg of MLCAPE
as far north as the Straits/eastern Upper to near 1,000 J/kg near
the M-72 corridor. Limited sunshine may hinder instability to some
extent, but with roughly 30 kts of bulk shear progged to be in place
Thursday afternoon, prior to the system`s cold frontal passage
Thursday night, lends thought that a few stronger storms are not out
of the question. Heavy rain will also be a concern as PWs are
expected to climb to near 2.00 inches with a K-index in the mid-
upper 30s by Thursday morning. All supported with WPC`s Day 3
Excessive Rain Outlook encompassing a majority of northern Lower
Michigan. Cold front sweeps across northern Michigan Thursday
night...likely bringing any periods of steadier rain to an end with
just some lingering showers scattered about.

High temps Wednesday ranging from the mid 70s to the low 80s before
cloud cover/precip lends itself to cooler temps on Thursday...
generally from the low-upper 70s.

.LONG TERM...(Thursday night through Monday)
Issued at 348 PM EDT Mon Aug 14 2017

Primary concern for the extended is a late week storm system that
should be clearing the region through the day Friday. High pressure
will be in control after that, with perhaps a northern stream wave
bringing a line of showers into the area early next week. Not a lot
of confidence with that feature however. Temperatures will be near
normal to start the period, but will warm through the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 707 PM EDT Mon Aug 14 2017

A few showers remain possible, especially vicinity KMBL this
evening. Otherwise, will be on the lookout for the development of
light mist/fog, especially at KAPN, which received some
appreciable rainfall today. May see the same at KPLN, with perhaps
some broken MVFR producing cigs during the early morning hours.
Otherwise, VFR conditions expected to prevail under passing mid
level clouds tonight and the development of relatively high based
cumulus on Tuesday. Light winds will continue.


&&

.MARINE...
Issued at 348 PM EDT Mon Aug 14 2017

Generally light winds thru Tuesday night, with ongoing westerly
breezes becoming northerly as high pressure builds toward
Superior. Potential for a few strong thunderstorms for the Lk Huron
waters thru early this evening. Winds will veer easterly by
Wednesday.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

UPDATE...MB
NEAR TERM...JZ
SHORT TERM...MG
LONG TERM...AM
AVIATION...MB
MARINE...JZ



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