Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 291705
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
105 PM EDT SUN MAY 29 2016

.UPDATE...
Issued at 1023 AM EDT Sun May 29 2016

Low pressure center has reached Lake Superior this morning...with
associated cold front extending southward thru Wisconsin. Cooler
air has filtered into Wisconsin along and behind this cold
front...as has a broad area of low clouds across Wisconsin...Wrn
Upr Michigan and the NE two- thirds of Minnesota. Broken area of
showers continues to gradually march east thru Wisconsin along
the front. No thunder to speak of yet as we begin to emerge from
the overnight/early morning period of minimum diurnal instability.
Temps are warming thru the 70s ...and dwpts remain in the lower
60s attm...but of which are behind yesterday`s temp/dwpt trends.

Latest RAP13 rotates the cold front and the leading edge of the
low clouds along that front into western sections of our CWA this
afternoon...which will likely limit instability and thus
convective development potential for Ern Upr and NW Lwr Michigan.
MUCAPES only rise to around 500-700 J/kg this afternoon across
this area. Even NE Lwr Michigan doesn`t appear to destabilize much
more than that. Better instability (MUCAPES of 1500-2000 J/kg) as
well as the 850 mb theta e ridge appear to target the Thumb area
of Michigan this afternoon more so that eastern sections of our
CWA. Certainly we will likely see some showers and thunderstorms
this afternoon...with best POPs and chance of some stronger storms
across NE Lwr Michigan...but chances of severe storms appears to
be waning. Will maintain highest pops across this area (likely)...
tapering to smaller chances in our western CWA (small chance)...
and will watch closely now thunderstorm intensity evolves as
cooler/drier/more stable air slowly presses into our CWA with
FROPA.

&&

.SHORT TERM...(Today and tonight)
Issued at 401 AM EDT Sun May 29 2016

Overview: Progressive short wave trough axis is swinging through
the upper Midwest and into the far western Great Lakes region
this morning. Broader area of surface low pressure is across the
upper Midwest with some semblance of pre-frontal troughing working
into lower Michigan. Main cold front resides from western
Wisconsin down through Iowa. Deep S/SW flow ahead of this system
has maintained a fairly moist boundary layer across the Great
Lakes with sfc dewpoints currently holding in the 59 to 65 degF
range, and we still have a fair amount of MLCAPE out there this
hour (several hundred J/KG across NE lower MI per SPC meso
analysis page) although a good amount of CINH as well given the
time of day.

Meanwhile, sharply defined dry slot has punched up into the western
Great Lakes ahead of the parent upper low. Combined with daytime
heating on Saturday, helped to spur on the earlier line of convection
from Wisconsin into Illinois. That activity died quickly upon reaching
Lake Michigan. But there is yet another thin line of showers that
has spread up from SE lower Michigan through Saginaw Bay area and
up along the Lake Huron coast into NE lower MI apparently along
that axis of modest instability nosing up through the area.

Today: Convective development late morning through the afternoon
is of course the main forecast issue. But first off, will have to
account for remnant showers rolling up along the Lake Huron
coastline. Not a big deal, but will has some low end chance pops
through early morning.

Then, upper level short wave trough still expected to swing
through the region late this morning through the afternoon, with
the strongest upper level height falls taking shape across Upper
Michigan/Lake Superior. Attending surface low advances across Lake
Superior and into Ontario by evening with the surface cold front
slipping through the region this afternoon. We should have a
decent amount of instability to work with this afternoon
especially across NE lower MI where warmest temps (back into the
lower 80s) and highest dewpoints will be found, with forecast
soundings suggesting 1000-1500 MLCAPE across NE lower michigan
assuming we can keep those dewpoints up around 60F. But, overall
QG-forcing for ascent is rather unimpressive this afternoon while low
level convergence with the front itself gets a bit muddied as
winds turn a bit more SW behind our pre-frontal trough. Still,
cannot rule out the chance for showers/thunder just about
anywhere in the CWA this afternoon. But I have focused the better
chances across NE lower Michigan and particularly along the Lake
Huron coast where added low level convergence off the lake will
be had.

Severe weather threat: I`m not wowed. But the combination of
decent instability, some modest 0-6 KM bulk shear values pushing
40 knots and freezing levels largely under 11K feet does support a
marginal severe storm threat across NE lower MI as depicted by
Day 1 SPC outlook.

Tonight: Upper trough and attending surface low continues into
Ontario. Wrap around/deformation forcing/precip (currently across
northern Minnesota) will be sliding through Upper Michigan and
parts of far northern lower Michigan through the evening. Thus
will maintain chancy pops for showers across those areas before
ending precip overnight.

.LONG TERM...(Monday through Saturday)
Issued at 401 AM EDT Sun May 29 2016

...Dry early part of the week then turning wetter for midweek...

High Impact Weather Potential: Minimal through Wednesday.

Pattern Synopsis/Forecast: Split pattern continues across North
America...with an active southern branch with short wave troughing
over southern California and moving into the midwest...with tropical
cyclone "Bonnie" getting funneled toward South Carolina.  To the
north of the tropical storm is an upper level ridge extending
northwest from the Atlantic up across the Great Lakes and into
northern Canada.  Northern branch upper low spinning over British
Columbia...pinched between the aforementioned ridge axis and another
closed high over Alaska.  Short wave trough moving into the midwest
has an associated surface low over southern Minnesota...with a
trailing cold front back into the southern Plains.

Midwest short wave trough will track across the Great Lakes over the
next 24 hours...while trough over British Columbia will advance very
slowly east into the northern plains by midweek and eventually
reaching the upper Lakes in the Thursday time frame.  A cold front
will be draped across Lake Superior and adjacent portions of Ontario
Monday...and will likely sag into Michigan Monday night into Tuesday
as a short wave trough ripples by the forecast area to the north.

Primary Forecast Concerns: Increasing rain chances toward midweek.

Monday...A drop in boundary layer humidity is expected for Memorial
Day Monday with dew points expected to fall into the 50s. Should be
a decent bit of sunshine with highs expected to range from the upper
60s over parts of eastern upper to the lower 80s over northeast
Lower. Height falls passing by to the north of the forecast area
will push a cold front south and into northern Michigan Monday night
into early Tuesday.  Not expecting much with this feature
initially...with generally clear to partly cloudy skies expected
Monday night and lows ranging from the mid 40s to lower 50s.

Tuesday...Short wave trough will move into the northern/central
plains states Tuesday...with some short wave ridging out ahead of
this feature.  Cold front will likely lie across lower Michigan
though instability looks pretty thin and think we can squeeze out
another dry day and will maintain that forecast trend.  A little
uncertain as to how quickly rain chances will increase across
northern Michigan as upstream short wave trough will make only slow
progress toward the upper Midwest/upper Great Lakes.  Will bring
chance PoPs into much of the area Tuesday night for the time being.

Extended Forecast (Wednesday through Saturday)...Upstream short wave
trough will still be...well...upstream of Michigan Wednesday though
associated cold front will probably be inching into the forecast
area Wednesday night.  So will continue with shower/thunderstorm
chances for Wednesday and will probably be a warm and sticky day.
Will keep precipitation chances in for Thursday given uncertainty
regarding frontal timing across lower Michigan (it is possible that
Thursday could end up being dry).  Will dry things out for
Friday/Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 105 PM EDT Sun May 29 2016

Scattered to numerous showers and thunderstorms will redevelop
this afternoon and continue into this evening across Nrn Lwr
Michigan along and ahead of a cold front sweeping thru the region.
Overall conditions will remain VFR thru this evening...although
conditions may briefly drop to MVFR and possibly IFR within
heavier showers and storms. Areas of fog are expected to develop
overnight...dropping conditions to MVFR into early Monday morning.
Dry weather and VFR conditions will return to all TAF sites for
the rest of Memorial Day. S/SW winds gusting to 20 kts this
afternoon will diminish to AOB 10 kts this evening...initially
shifting to the W/SW with FROPA and then to the NW later tonight
into Monday.

&&

.MARINE...
Issued at 401 AM EDT Sun May 29 2016

Some gustier SW winds will be found across the region today
particularly from Manistee up through Sleeping Bear Point. May
need to hoist another SCA for that area today. Otherwise, winds
and waves should largely remain under headline criteria. Winds
turn a bit more westerly tonight through Monday and again with
perhaps some gustiness. But no headlines are anticipated at this
time.

&&

.APX Watches/Warnings/Advisories...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY until 10 PM EDT this evening for LMZ345-346.

LS...NONE.
&&

$$

UPDATE...MLR
SHORT TERM...Adam
LONG TERM...JPB
AVIATION...MLR
MARINE...Adam



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