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Area forecast discussion 
National Weather Service Marquette Michigan
726 am EDT Sat Jul 26 2014

Short term...(today and tonight)
issued at 701 am EDT Sat Jul 26 2014(today through tonight)

Latest WV satellite imagery shows shortwave over southern
Saskatchewan this am with area of convection associated with front
pushing ahead of this feature over northern Ontario/Minnesota arrowhead
region. This activity should lose steam as it drifts to the east
this morning into increasingly stable air per latest BUFKIT

Drier air pushes into the region today ahead of the shortwave and
will bring to an end any precipitation that persists. With
decreasing clouds with increase mixing on the lower levels due to
decent 850-500 mb q vector divergence...area to see plenty of
sunshine today except for far east where clouds to linger longest.
Still lots of moisture around central and eastern Upper Michigan
although the west will mix out quite well thus some light showers
and a thunderstorm or two may develop as lake breezes develop and
move inland. With 850 mb temperatures rising to around 16 c over the WI
border region and with westerly downslope winds in place have
continued trend of holding a few degrees above guidance for
afternoon highs. Expect Lower/Middle 80s along areas favored by
downslope winds with some moderation along the Great Lakes shores.

For tonight...shortwave and associated surface low pushes into the
region. Combination of surface front and decent 850-500 mb q vector
convergence moving into the region brings the higher chances for
precipitation. The better forcing arrives after maximum heating with mu
convective available potential energy on the wane by the time the better forcing arrives. Still
enough instability to warrant mention of thunderstorms until late
evening/early morning...then showers after then. Temperatures will
still stay above seasonal averages overnight with persistent cloud
and with cold air advection holding off beyond the short term

Long term...(sunday through friday)
issued at 701 am EDT Sat Jul 26 2014

For major changes planned. The upper low over the
Canadian prairies will move just south of area on Sunday as it
interacts with the deep trough over Hudson Bay. This will allow the
surface low to move across the area Sunday morning...causing the
forecast area to be under the comma head moisture area for much of
the day. As looks like the central portion of the forecast
area will be under the best upward vertical motion due to the
deformation axis and low level frontogenetic circulaion. In
addition...the north central part of the forecast area will see
upslope flow due to north-NE low level flow as the day GOES on. Will
therefore increase probability of precipitation in the central part of the forecast area to
categorical. looks like a cool and damp day on
Sunday...more like September than late July.

However...the low pressure will move east fairly rapidly by Sunday
evening...with high pressure building into the northern plains/upper
MS valley Sunday night. In addition...strong cold/dry advection and
downward motion will move across the area Sunday night which should
allow for precipitation to move out of the region late Sun afternoon/sun
evening and skies to clear out. With 850mb temperatures dropping to +6c
across the region...expect a chilly night with temperatures dropping into
the upper 40s/lower 50s. With the winds staying not expect
temperatures to bottom out as much as one would think with these type of
850mb temperatures and the drying aloft /pwat values lower to below 0.75

In the extended periods...with the upper trough remaining in place
across the east...expect somewhat unsettled and cool weather to
continue through much of the week...although a gradual warmup will
be in store toward the end of the work week. It looks like there
will at least be small chances for showers or storms each afternoon
with the upper trough and cool air aloft...and numerous short waves
rotating through the area in northwest flow. Will therefore have to
maintain chance probability of precipitation for the interior parts of the area each day in
the extended due the likelihood of diurnal type showers through the
week. However...many spots will not see rainfall during this time
period. Temperatures will remain below normal through the week...although
will rise to closer to normal by Friday.

Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 726 am EDT Sat Jul 26 2014

Showers and thunderstorms continue to move across the area ahead of
a weak shortwave moving through the Minnesota arrowhead region early this
morning. Subtle surface trough the focusing mechanism for this
convection...with this feature expected to wash out as the shortwave
moves through later this morning. Once that occurs...drier air above
the boundary layer will move in with MVFR and some IFR ceilings giving
way to VFR when daytime mixing arrives in earnest. Better chances
for precipitation along with lower ceilings and reduced visibilities
arrives with the next shortwave and associated surface low. MVFR
ceilings return with the precipitation and cannot rule out IFR late in
the forecast at kcmx as easterly upslope flow develops. Otherwise
winds to remain below 10 knots through the forecast.

Marine...(for the 4 am Lake Superior forecast issuance)
issued at 701 am EDT Sat Jul 26 2014

Winds to remain under 15 knots early in the forecast as pressure
gradient remains weak under influence of a weak ridge. Winds will
pick up Sunday as a surface low moves through the area and northerly
winds ont the backside combined with cold air advection will produce
gusts to 20 to 25 knots Sunday and Sunday night. Wind gusts pick up
again Tuesday evening over the Eastern Lake but remain under 20
knots. After then...high pressure will prevail over the region and
will keep winds below 15 knots.

MQT watches/warnings/advisories...
Upper Michigan...
Lake Superior...
Lake Michigan...


Short term...rjt
long term...mrd

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