Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 210148

Area Forecast Discussion
National Weather Service Gaylord MI
948 PM EDT Sat Jul 20 2019

Issued at 948 PM EDT Sat Jul 20 2019

Widespread convection has exited east. Rain cooled outflow air
forms an effective cold front that has moved south out of MI.
Actual synoptic cold fronts were in central lower MI, and over
northern Superior. Though widespread precip is gone, we have seen
some drizzle swing into parts of nw lower MI this evening, as our
low levels remain quite moist. Low clouds have diminished north of
M-32, but remain fairly extensive south. Guidance keeps the
threat for some drizzle or very light rain going thru about
06z/2am before fading, in line with lower cigs gradually advecting
out of northern MI. Otherwise not expecting precip tonight, with
partial clearing occurring from south to north.


.NEAR TERM...(Through Tonight)
Issued at 352 PM EDT Sat Jul 20 2019

High Impact Weather Potential: Severe storm threat over the next
several hours. Ongoing flooding in the SW counties.

Pattern Synopsis/Forecast: Thunderstorm complex and well defined
MCV is currently advancing through northern Lower Michigan
producing heavy rain and some severe weather, primarily south of
M-32. Trailing rain shield stretches up into eastern Upper
Michigan. Second complex of storms is not too far behind, pressing
through central Wisconsin, and will be moving through the region
over the next 3 to perhaps 6 hours, although the "business" end of
that convection appears to be taking a more southern track toward
southern Lower Michigan where better instability resides.

Primary Forecast Concerns: Ongoing severe storm and heavy rain

Ongoing round of showers/storms will move through the region
through late afternoon/early evening. Second round will follow
through early to mid evening although as mentioned, stronger part
of that complex may take a southern track into southern Lower
Michigan with more of the stratiform rain shield impacting
northern Lower. But the severe weather threat for us will
probably diminish after this first line and MCV exits the region,
fairly close to the end time of the ongoing severe thunderstorm
watch. Until then, will probably be able to start trimming out the
western sections of the watch in the next couple of hours.

Flooding threat from earlier training thunderstorms across
Manistee county is also diminishing...stationary storms and heavy
rain have been pushed out the area by the convective line/MVC.
Given the very hefty rainfall amounts through that area (possibly
as much as 10 inches) Will have to assess whether or not the
ongoing flash flood warning will need to be replaced by an areal
flood warning to address standing water issues.


.SHORT TERM...(Sunday through Tuesday)
Issued at 352 PM EDT Sat Jul 20 2019

High Impact Weather Potential: Minimal.

Pattern synopsis/forecast: By Sunday morning, fairly zonal upper-
level flow is anticipated across the region with two surface
boundaries of note. The primary and more impressive cold front is
expected to be situated downstate...generally running west to east
from near Chicago to Lake Erie. Secondary/weaker front progged to be
draped from the U.P eastward into Ontario and Quebec. These
boundaries should both slowly sag south throughout the day before
being ushered well off to the south and east as broad mid-level
troughing with several embedded smaller shortwaves arrives overhead
Sunday night through the remainder of the forecast period. However,
despite renewed troughing, high pressure nosing into the west should
allow for mainly dry conditions to prevail across much of northern
Michigan through early in the upcoming week.

Primary forecast concerns/challenges: Decreasing PoPs Sunday.
Temperature trends through the forecast period.

The aforementioned frontal boundaries are both expected to sag south
throughout the day Sunday, ultimately allowing cold air advection to
develop through much of the day Sunday. Much drier air will also
accompany this cooler airmass (PWs sink from 0.75 - 1.25 inches
early in the day to sub 0.75 inches by Sunday evening). Suppose
there could be a lingering early day shower, mainly south of M-55,
but expect this to be the exception rather than the rule. otherwise,
more sun than clouds are expected across northern Michigan with much
more comfortable temps/dew points as highs top out within a degree
or two of 80 degrees area-wide.

While I see no glaring evidence to add low PoPs into parts of the
forecast area Sunday night, could foresee a solution that brings a
few isolated sprinkles or light showers as a result of increased
mid-level support out ahead of the aforementioned incoming shortwave
trough axis. Of course, the limiting factor will be paltry deep
layer moisture, so have opted to keep the forecast dry through this
period as least at this point.

Primarily dry conditions are expected to prevail through the early
part of the upcoming work week as high pressure noses into the
region from the west. Lots of sunshine under broad north-
northwesterly flow will be the rule leading to slightly below normal
high temperatures ranging through the 70s area-wide.

.LONG TERM...(Tuesday night through Saturday)
Issued at 352 PM EDT Sat Jul 20 2019

High Impact Weather Potential: Minimal.

Broad northwesterly flow continues through at least Wednesday
night/Thursday morning with little in the way of impact. Could
foresee a solution that brings a few light/scattered showers to
portions of the region Tuesday night/Wednesday, but with little
confidence at this point given subtle guidance differences with
respect to timing/strength of embedded shortwaves in larger parent
troughing. Perhaps the next widespread chance of showers and perhaps
storms arrives late in the week into next weekend as a cold front is
expected to drop across the region.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 728 PM EDT Sat Jul 20 2019

IFR cigs possible near the Great Lakes this evening.

Widespread shower/t-storm activity has exited, though some showers
linger in spots. Somewhat cooler and less humid air will gradually
make inroads into northern MI. However, humid air over the Great
Lakes has resulted in some marine stratus, and this will impact
some TAF sites with IFR cigs for part of this evening. This should
further erode overnight, and Sunday looks VFR, quiet, and much
less humid.

Light nw to n winds thru the forecast.


Issued at 352 PM EDT Sat Jul 20 2019

Cold front will sag down through the region later tonight and turn
winds decidedly into the northwest with some gustiness lingering
into Sunday. Until then, winds will remain somewhat erratic owing
to ongoing convection moving through the region...with gusts
occassionally and briefly reaching small craft criteria.




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