Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 230155

Area Forecast Discussion
National Weather Service Gaylord MI
955 PM EDT FRI JUL 22 2016

Issued at 955 PM EDT Fri Jul 22 2016

Quiet night and clear skies ahead as elongated surface ridge axis
continues to build into the western Great Lakes. Afternoon minimum
surface dewpoints managed to dip down through 50s across interior
sections (49F at HTL), and along with clear skies and calm winds,
suggests we could see overnight lows dipping into the 50s as well
at the normally colder spots. Have thus lowered forecast lows


.SHORT TERM...(This evening and overnight)
Issued at 330 PM EDT Fri Jul 22 2016

Overview...A weak cold front/dry line is moving through the forecast
area and is slowly drying the dewpoints across the forecast area.
Temperatures are ranging from the mid 80s to lower 90s inland with
the lake shore temperatures in the mid 70s. Upstream is an area of
sfc high pressure in the Dakotas with a 500 mb flat ridge over the
Northern Plains.

Tonight...High pressure will continue to settle into the region
behind the dry line and continue the dry weather. With the lower
dewpoints, there is little to no threat for fog, and with the 500 mb
flat ridge pushing into the Upper Great Lakes, the low temperatures
will probably drop to only the lower 60s across the region.

Saturday...As the sfc high and the 500 mb ridge moves into the
forecast area, we will get another dry day. There may be some late
afternoon high clouds moving into the region as convection gets
going in the Upper Mississippi Valley.

.LONG TERM...(Saturday through Friday)
Issued at 330 PM EDT Fri Jul 22 2016

High impact weather potential: Lingering heat. Potential for more
stormy weather late Saturday night through Sunday night.

Pattern synopsis/expected evolution: Large scale pattern set to go
through some changes in the coming days, the most notable being a
slow relaxation of northern plains ridging (really the northward
extension of current central plains heat dome) and the development
of a more active/energetic northern tier flow regime. While the
former will help squash upstream heat further south with time, the
latter will attempt to briefly surge some of it back north, bringing
us the potential for another round of showers and thunderstorms in
the process to end the upcoming weekend.

Primary forecast concerns/challenges: Shower and thunderstorm
evolution and intensity Saturday night into Sunday evening.

Details: Overhead mid level ridging Saturday quickly yields to the
developing more aggressive northern tier flow regime and embedded
mid level waves Saturday night. Unfortunately, while these larger
scale changes are of rather high confidence, how the attendant
sensible weather unfolds is anything but. Real uncertainty remains
centered on expected upstream convective growth (MCS?) Saturday
evening and what effect it will have on our weather heading through
later Saturday night into Sunday. Simple pattern recognition and
anticipated placement of larger scale features supports rather rapid
upscale convective growth Saturday evening back across the Upper
Mississippi Valley and western Lakes along northward surging
moisture/instability plume on nose of developing low level jet. Deep
layer flow suggests what ever forms will propagate steadily east,
likely pushing into our area later Saturday night and Sunday
morning, with this round of showers/storms exiting/fading out,
waiting for additional late day development along trailing cold
front. Per the usual, timing will be everything with regards to
thunderstorm intensity/severe weather potential (an earlier arrival
of MCS will may allow for some decent storm structure to still
exist, as well as allow more destabilization during the afternoon
for approaching cold front to work on). Decent wind fields aloft
(especially north) does raise some concern for isolated severe
weather. Area is smack-dab in the middle of SPC`s day 3 marginal
risk, which definitely makes sense with all the uncertainties with
regards to early day convective evolution and its subsequent affects
on what occurs later in the day.

Any lingering activity looks to come to an end early Sunday night
after cold frontal passage, setting the stage to what should be a
dry Monday. Now, post-frontal cooling is not quite as aggressive as
the drying , and what there is may largely be offset by more
sunshine Monday. Highs both afternoons will mostly be in the 80s,
although with some uncertainty on Sunday owning to rain and cloud



Flow over the northern tier of the CONUS will remain nearly zonal,
while the warm dome setup over the southern tier persists. Will see
a small chance for some scattered showers as we near mid-week...with
a weak moving through ahead of deeper troughing to the west. This
deeper troughing will move overhead late in the week, with more
scattered showers possible ahead of the trough axis clearing the
state. There looks to be a bit of a pattern change as these height
falls start to arrive late in the week and persist over the eastern
CONUS into next week. This should help to get temperatures back down
to near normal values, with the amplified ridging remaining west of
the Rockies.



.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 758 PM EDT Fri Jul 22 2016

Solid VFR conditions will persist through tonight and through the
day Saturday, as high pressure builds across the state. Risk for
fog/reduced vsbys tonight is very low, thanks to ongoing drying
and daytime heating/mixing. Light/calm winds tonight. Some
increase in winds Saturday although sustained winds will remain
largely below 10 knots. Lake breezes also likely on Saturday with
lake breeze directions developing at the terminal sites.


Issued at 330 PM EDT Fri Jul 22 2016

Tonight Through Sunday...Tonight and Saturday will feature high
pressure over the region, so will expect that the winds and waves
will remain below small craft conditions. Saturday night, a warm
front will begin to move into the Upper Great Lakes and produce
thunderstorms. Winds and waves however, are still expected to be
under small craft conditions, although the thunderstorms may be wind
gusts above 35 knots which would lead to higher waves. Sunday, the
thunderstorm threat will begin to wind down, but the winds will
begin to veer to the SW and increase to 15 to 20 knots. At this
point it looks like the winds and waves will remain under small
craft conditions, but it will be something to watch.


.APX Watches/Warnings/Advisories...


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