Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 140347
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1147 PM EDT Sun Aug 13 2017

.UPDATE...
Issued at 1051 PM EDT Sun Aug 13 2017

One lone shower remains, trapped within what was earlier the
eastern upper convergence axis. This will end quicky as all
diurnal support is already lost. Otherwise, just expecting some
passing high and mid level clouds overnight, with perhaps just
deep enough moisture to kick off a few sprinkles/very light
showers across southern areas by morning. This idea will be
introduced to the inherited forecast.

&&

.NEAR TERM...(Tonight through Monday)
Issued at 305 PM EDT Sun Aug 13 2017

...Scattered shower/storm threat returns Monday...

High Impact Weather Potential: Isolated thunderstorm possible across
interior eastern Upper through early this evening. Chance of
additional thunderstorms Monday afternoon, primarily across
northern Lower.

Pattern Synopsis: This afternoon`s surface analysis reveals a broad
area of high pressure across the Great Lakes, Upper Mississippi and
Ohio Valleys, along with a stalled frontal boundary focused well to
our north across central Ontario. Primary focus through Monday will
revolve around a compact yet potent shortwave currently centered
over the eastern Dakotas, which is progged to steadily progress
eastward through the start of this week while renewing scattered
shower/storm chances locally.

Primary Forecast Concerns/Challenges: Convection chances for the
remainder of this afternoon and again Monday afternoon.

Surface high pressure squarely overhead this afternoon will
gradually drift east tonight. Quiet weather is expected to prevail
across the bulk of northern Michigan right through Monday
morning. However, with that being said, there remains a small
chance for an isolated shower or storm, primarily along the
typical lake breeze/convergence axis across inland eastern Upper
Michigan where dew points have climbed to the mid-upper 50s and
SPC`s surface analysis suggests upwards of 500 J/kg of MUCAPE has
developed (cu have been bubbling since roughly ~17z or so across a
narrow corridor from roughly Newberry eastward to Drummond
Island). Hi-res guidance trends continue to remain fairly
steadfast in at least isolated development by late afternoon. See
no reason to stray from low end PoPs/thunder chances, although
forecast soundings suggest a cap centered around ~875 mb may
really struggle to completely erode, which should limit overall
coverage/strength of any convection. Further south...perhaps a
stray afternoon/early evening shower across far northeast Lower;
otherwise, near-normal temperatures and diurnally driven cu
dotting the map will be the rule. Bulk of the area`s low temps
tonight ranging from the upper 40s to the low-mid 50s.

Any convection and diurnally driven cu fade quickly heading into
tonight. Would expect some mid cloud to sneak into at least far
western areas by Monday morning as the aforementioned upstream
shortwave barrels toward the region. Scattered shower and
thunderstorm development is anticipated to be underway by midday
Monday. Primary threat for thunder on Monday lies east of I-75
coinciding with theta-e ridge axis and greater instability across
northeast Lower. At this juncture, a lack of impressive forcing and
winds aloft should preclude much in the way of severe weather.

&&

.SHORT TERM...(Monday night through Wednesday)
Issued at 305 PM EDT Sun Aug 13 2017

...Shower chances Monday night and late Wednesday...

High impact weather potential...none.

Incoming shortwave will deamplify as it crosses northern MI Monday
night. This trof will support lingering convection. Shortwave
ridging arrives Tue night, between upper lows over Quebec and s
central Canada. Associated strengthening warm advection could
support some showers at some point on Wednesday, as heights start to
fall again and as low pressure moves toward the upper MS Valley.

On Monday night, a weak surface low will cross southern lower MI - a
reflection of the shortwave digging into northern MI. Respectable
pops remain in order in the evening, in the east with leftover
diurnal instability, and in the west as activity originating in WI
tries to work across the lake. ECMWF (much more so than the Nam)
believes the latter will have considerable success working into nw
lower MI. Smallest pops will be north of the bridge, where
instability will be harder to come by. Nothing terribly strong/svr
is expected, with the better shear values to our south, and
instabilty waning with time. By overnight, hard to justify more
than a small chance of showers in ne lower MI, as western sections
see subsidence/drying work in just behind the shortwave.

Ridging surface and aloft will result in drier wx Tuesday, Tue
night, and Wed morning. With slowly lengthening nights and dew
points in the 50s, patchy fog is a possibility very early on Tuesday
and Wednesday. Otherwise this period is quiet and pleasant.

Next shortwave trof will advance across the northern plains on Wed,
with a surface low reaching the WI/MN border by early evening. An
associated warm front will advance into southern lower MI. Some
showers (and maybe a stray t-storm) will develop north of the warm
front in the afternoon. Better rain chances will be after sunset,
but slight-chance to chance pops in order across much of northern
MI, highest TVC-HTL and points sw of there.

Min temps both nights mid 50s to around 60f. Max temps mid 70s to
around 80f, with some lower 80s sneaking into nw lower MI on Wed.

.LONG TERM...(Wednesday night through Sunday)
Issued at 305 PM EDT Sun Aug 13 2017

A somewhat progressive pattern continues into the long term forecast
period with a weak area of low pressure over the Great Lakes
beginning the period, producing showers and possibly thunder
Wednesday night through Thursday. This appears to be the best chance
for precipitation, although models are in agreement with the
remainder of the period having periodic chances of showers with a
few areas of upper level low pressure and accompanying moisture.
Daytime temperatures will be in the mid to upper 70s (eastern upper:
low to mid 70s), while lows will dip down to the upper 50s to low
60s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1145 PM EDT Sun Aug 13 2017

Overnight high clouds expected to give way to a building cu field
later today as an upper level disturbance approaches. Expect some
showers to develop today, with KAPN standing the best chance to
see some of this shower activity. Otherwise, expecting both cigs
and vis to remain in VFR category through the duration. Light wind
fields to persist.

&&

.MARINE...
Issued at 305 PM EDT Sun Aug 13 2017

Light winds/waves are expected over the next several days. Quiet
weather conditions are anticipated through tonight, aside from a
couple of afternoon showers/storms across inland eastern Upper
Michigan, which may flirt with the St. Marys River system. The next
threat for scattered showers and a few storms across the entire
region arrives Monday.


&&

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

$$

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



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