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Area forecast discussion 
National Weather Service Gaylord Michigan
358 PM EDT Wednesday Apr 1 2015

Near term...(this evening through tonight)
issued at 345 PM EDT Wednesday Apr 1 2015

..rain (may be mixed with snow) eastern upper and chance of
rain showers and possibly thunderstorms northern lower...

On the latest surface weather map...1021 mb high pressure is
centered across southwestern Quebec with 994 mb low pressure
centered across the northern border of North Dakota and Minnesota.
Surface observations and satellite imagery showed middle level clouds
overspreading the region from the west. The main short term forecast
concerns revolve around precipitation chances through tonight and
precipitation type across eastern upper.

Surface warm front and associated moisture will sweep across eastern
upper and The Straits region this evening. Southern end of best f-
general/q-vector forcing appears to just scrap eastern upper. Models
have this region pegged for between a tenth and a quarter of an inch
of precipitation through 06z tonight (with a half to three-quarters
of an inch not too far off to the north). As far as precipitation
type GOES...model soundings leave room for evaporative cooling
processes to cool the column enough for a mix with or change over to
all snow before warmer air takes. Therefore...have allowed for a mix
of rain and snow across northern Chippewa County this evening with
little or no snow accumulation expected before changing over to all
rain. looks like we will have to wait for elevated
convection to generate any possible rainfall. Convection has just
initiated across east central Minnesota and northwest Wisconsin (in
the right rear quadrant of a developing upper level jet). Middle level
instability increases late this evening and overnight across
northern lower with 700-500 mb lapse rates a robust 7.5 c/km. This
setup will bring a chance for a few showers and possible
thunderstorms during that time. Lows tonight only ranging from the
middle 30s north to the middle 40s southwest.


Short term...(thursday through saturday)
issued at 345 PM EDT Wednesday Apr 1 2015

..mild with Spring showers and perhaps some thunder then turning
cooler again...

High impact weather potential: risk for thunderstorms Thursday.
Severe weather not expected.

Pattern synopsis/anticipated evolution: 500 mb trough over the upper
MS valley Thursday will push eastward into the Great Lakes Friday and
Saturday. A brief period of deep southwest flow ahead of this
trough will bring Spring warmth and moisture into the region
Thursday...along with showers and a few thunderstorms until a cold
front sweeps across the area by middle-late afternoon. Cooler and dry
weather will return Thursday night and Friday...before another
disturbance moves into the upper Great Lakes region Saturday and
provides a chance for snow.

Thursday...aforementioned deep SW flow will be in full force early
Thursday...and will bring Spring moisture into the region /as precipitable waters
increase to around 1.00 in by midday/. Model soundings also show a
nice push of low level moisture just off the surface...and with
steep middle level lapse rates...MUCAPES will near 500 j/kg by middle
morning over parts of northern lower Michigan within pre-frontal airmass.
Cold front over WI at 12z will swing eastward into lower Michigan by 18z...
and this will coincide with increasing large-scale forcing as
right entrance region of 250 mb jet moves overhead and produces an
organized pocket of divergence aloft. Bottom line...plenty of
things coming together to support a period or two of showers and
possibly some thunder. Overall evolution and timing shown by
NAM/GFS are similar...and suggests showers continue to quickly
increase by middle morning over western and northern area...and by afternoon
for eastern areas. Will be hard to strictly rule out a chance for
showers/thunder even early in the day area wide given low level jet forcing
and potential for elevated convection. A few brief heavy
downpours will be possible...but limited instability will preclude
any severe weather. There may be a few peaks of sun early over
eastern areas...but clouds will be the rule. Highs will peak in the
50s to around 60.

Thursday night and Friday...cooler air will filter into the area
behind departing cold front...though little in the way of
precipitation expected. Models suggest a secondary cold front will
come through Thursday night...but lack of deep layer moisture should
prevent precipitation /though this will be something to watch for if
forcing increases/. Secondary front will be east of area Friday...
with only northwest flow and cold air advection expected. Cold air won't be sufficient for
any lake processes /it is April afterall/...with just partly to
mostly cloudy skies expected. Highs will reach the 30s to middle 40s.

Saturday...general troughiness aloft will persist...along with cool
weather conditions. Models show a weak disturbance rotating around
main upper trough. As this occurs...low level flow becomes SW
supporting some warm air advection/isentropic ascent. So a chance for snow /mixed
with rain?/ Seems warranted by midday - especially over northern areas.
Highs will reach the 30s to around 40.


Long term...(saturday night through wednesday)
issued at 345 PM EDT Wednesday Apr 1 2015

A fairly active end to the Easter weekend right on into next week is
expected as an initial northern-stream wave potentially followed by
a much more robust and moisture-rich system for early next week
impacts the area. As mentioned by the previous shift...confidence
remains rather low on how exactly the second half of the Holiday
weekend will play out. At this point...a tight baroclinic zone is
expected to be draped across Michigan with a secondary wave now
advertised to ride along that zone bringing frontogenetically
driven precipitation to at least parts of the area for Easter Sunday.
Thermal profiles continue to support rain/snow mix (if not all
snow... dependent on intensity). Still several days to watch how
this wave develops...its placement...and ultimately to Iron out
the specifics.

On to next guidance is still in support of low
pressure developing on Monday over the plains...sliding into the
Great Lakes by midweek. As clyclogenesis gets under way...a warm
front is expected to lift toward the County Warning Area...potentially bringing
several bouts of precipitation from as early as Monday all the way
to the Wednesday time frame. Being 5+ days away...the typical
uncertainties still exist as guidance continues to vary drastically
in time (as much as 36 hours) and placement of the aforementioned low
pressure. As it sits now...the spectrum of possibilities in terms of
sensible weather for northern Michigan include anything from
rain/thunder to freezing rain/wintry mix to all snow. Have gone
ahead and made a mention of the potential for active weather in the
latest severe weather potential statement.


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 142 PM EDT Wednesday Apr 1 2015

High pressure will move off to the east today as low pressure and
an associated cold front approach from the west later tonight and
moves through by Thursday afternoon. This will lead to a tighter
pressure gradient increasing winds. In addition...low level wind
shear is expected to develop at all taf sites this evening.
Showers and possible thunderstorms are likely at some point
between middle morning Thursday and Thursday afternoon as the cold
front moves through. Ceilings/visibilities are expected to be VFR through the
period...though MVFR ceilings are possible in showers.


issued at 345 PM EDT Wednesday Apr 1 2015

The surface pressure gradient between departing high pressure and
approaching low pressure will continue to tighten up tonight. This
will lead to gusty southerly winds and small craft advisories across
all marine nearshore zones. Gusty winds will continue Thursday out
ahead of and behind a surface cold front which will move through the small crafts will continue through late afternoon.

Low pressure moves by to our south on Friday...with what looks like
marginal northwest winds for headlines.


Apx watches/warnings/advisories...
LH...Small Craft Advisory from 9 PM this evening to 5 PM EDT Thursday
for lhz345>349.
Lm...Small Craft Advisory until 5 PM EDT Thursday for
Small Craft Advisory from 9 PM this evening to 5 PM EDT
Thursday for lmz341.
Ls...Small Craft Advisory until 5 PM EDT Thursday for lsz321-322.



Near term...Sullivan
short term...Smith
long term...gillen

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