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Area forecast discussion
National Weather Service Gaylord Michigan
124 am EDT sun Apr 20 2014
issued at 347 PM EDT Sat Apr 19 2014
High pressure will move east away from the Great Lakes region. Low
pressure passing to our north early Sunday will drag a cold front
into northern Michigan. That front will stall...leading to a period
of damp weather that begins late tonight and lasts until at least
Monday. Temperatures will be relatively mild Sunday and
Monday...then cool off yet again.
issued at 919 PM EDT Sat Apr 19 2014
Have sped up initial rain shield into eastern upper by 1-2 hours
given extrapolation based on current radar trends. This is fully
supported by recent hrrr/rap runs. Freezing rain potential is
still there with drm 33/26 as of this writing...with smaller
chances at anj 37/25 and ciu 36/25. Will continue to monitor temperatures
and will consider a Special Weather Statement if we cool a few more degrees /which could
bring a few Road surfaces to near 32/.
No other changes needed at this time.
Short term...(this evening through tonight)
issued at 347 PM EDT Sat Apr 19 2014
..rain to spread into eastern upper/far northern lower tonight...
High impact weather potential: minimal. Small chance for freezing
rain far eastern upper after midnight.
Pattern synopsis/forecast: afternoon surface/composite analysis
shows deep layer anticyclonic flow across the upper Great Lakes...
supplied by a surface ridge to the east of Michigan...and middle/upper
level short wave ridging crossing Wisconsin/Michigan this
afternoon. Warm advection west of the middle level ridge axis pushing
a thicker band of cloud cover across Lake Superior and Upper
Michigan...with radar returns out over The Big Lake though low
layers were quite dry. Narrow low/middle level Theta-E ridge axis
extends northeast from eastern Nebraska/Kansas into Minnesota...with
a concomitant band of rain showers.
As surface high and short wave ridging continue to give way...warm
advection pattern will begin to impact northern Michigan tonight.
Theta-E ridge axis will gradually "tip over" toward eastern
upper/far northwest lower as the night progresses...advecting deep
layer moisture into northern portions of the forecast area
(precipitable water values 0.75-1.00 inch).
Primary forecast concerns: timing of rain threat into eastern upper
and northwest lower tonight...and maybe a question of precipitation type
across eastern upper overnight (freezing rain?).
Tonight: quiet start to the evening as cloud cover across eastern
upper will likely thin out for a brief time this evening before
returning later. Expect to see precipitation push into western
portions of Chippewa/Mackinac counties toward midnight...then slowly
push east into far eastern upper and far northwest lower Michigan
during the early morning hours. Much of northeast lower Michigan
and M-55 corridor should remain dry until closer to daybreak.
Current precipitation band upstream not overly impressive...but
intensity expected to improve tonight as deep layer moisture
increases and some entrance region jet dynamics get involved. So
expect 12h rainfall amounts across eastern upper of 0.25-0.50+ inch
Other forecast concern is surface temperatures across eastern
upper...currently within a couple degrees either side of 40 though
with dew points in the 20s. Cloud cover and a persistent south/
southeast breeze should keep temperatures from dropping quickly this
evening...but there is a good deal of room for evaporative cooling
once precipitation arrives which means temperatures may be very
close to freezing at that point especially across far eastern
upper. So can't rule out some threat for a little freezing precipitation
after midnight in the St. Mary's River vicinity...and will have a
"chancy" mention of this in the overnight grids.
Long term...(sunday through saturday)
issued at 347 PM EDT Sat Apr 19 2014
..rain chances once again on the increase...
High impact weather potential: early week rainfall and potential
impacts on current receding river levels.
Larger scale overview: split...kinda zonal low amplitude flow
expected to continue through the early portions of the
upcoming week. Initial deep layer Gulf moisture feed tied to
southern portion of the flow regime...as evident by band of heavy
rain moving up the southeast coast earlier this morning. Pacific
moisture plume associated with south Canada shortwave helping drive
a band of lighter rainfall into the northwest lakes and upper
Mississippi Valley. Pattern heading into the middle and end portions of
the long range period becomes increasingly uncertain...tied to
potential development of downstream North Atlantic blocking
(negative North Atlantic oscillation). Interestingly...both the GFS
ensemble suite and deterministic European model (ecmwf) show this development.
Unfortunately...this would support an increasingly "blocky"
pattern...and definitely not one supportive of any significant and
sustained warm-ups in our near future. As mentioned...however...past
seasonal trends do not support this strong blocking...and really
have to wonder if forecasts are being overambitious driving its
Primary forecast concerns/challenges: temperature and cloud trends
throughout the forecast. Accessing rain potential/amounts through
early week and possible impacts of such on area rivers.
Details: increasingly challenging rainfall forecast to start the
period. Current southern Canada wave races by well to our north
tonight into Sunday...dragging a weakening cold front into our area
as it does so. Front becomes essentially stationary as it
increasingly aligns itself with middle level flow pattern. Decent rer
jet dynamics and low level convergence helping focus rains along
this frontal axis...especially during the morning. Guidance trends
for the above have been noticeably slower and further north...
keeping the better rain across eastern upper/far northern lower
Michigan later tonight into the first part of Sunday (which is good
thing as greater impacts/flooding from past event were further
south). Hard to argue against such with complete detachment of middle
level parent system. Still...have to wonder of colder lake waters
may drive this front a touch further south. Will hedge north...but
leave some wiggle room via less than desirable broad brushed chance
probability of precipitation further south. Loss of best upper level jet structure and
limited middle level support argues for better rain coverage to come to
an end during the late morning and afternoon. Front become
re-energized heading into later Sunday night and Monday with
approach of next middle level wave. Even some potential for weak
surface low development along the temperature gradient...further enticing
low level mass convergence. Inherited forecast already well trended
this direction...although will begin the step-up process of
increasing probability of precipitation and quantitative precipitation forecast. Passage of primary shortwave trough keeps
some shower threat going Monday night...with conditions expected to
dry out as we head through Tuesday.
As for the all important rainfall amounts through this event:
steady-state nature of frontal axis definitely supports some decent
rain totals...with current indications this occurs north of the
hardest hit areas from this past weeks rain. Total rain amounts up
to and exceeding a half inch appears reasonable given prolonged
nature and precipitable water values surging to at or above one inch levels. Still...lack
of both more vigorous middle and upper level support and deep convective
threat (no thunderstorms) should keep amounts from getting too out
of hand...and really do not see any period were rainfall rates
become exceptionally heavy (also supported by no sref support for
greater than half inch amounts in a three hour period...with little
support for even greater than quarter inch amounts in three hours
being realized). Thus...no Flood Watch warranted...but definitely an
event to monitor for a potential further south and heavier rain
solution...the latter of which is a rather low probability scenario at this
Temperature trends through the early week period highly predicated
by rain coverage/timing and frontal placement. Forecast highs will
likely not mimic reality...but easily envision areas south of the
front Sunday and Monday making a run into the 60s (perhaps lower
70s?)...with readings several degrees colder to the north. Will
trend forecast toward a sharper temperature gradient. If things work
out right (further north solution)...Gaylord just might see their
first 60 degree day in over half a year! Not sold on that just
yet...however. Back to 2014 Spring reality on Tuesday...with highs
once again falling back through the 40s and 50s...several degrees
As alluded to earlier...pattern attempts to become a touch more
amplified/slower heading into the middle and end portions of the
week. Support is rather high that next Pacific slug of energy will
help carve out rather robust troughing into the northern plains just
after middle week...which looks to slowly slide across the Great Lakes
heading into the end of the week period. Exact timing/magnitude of
this system is anything but certain...and will no doubt change in
the coming days. Above simply forces a model blend forecast
approach...and one that continues to support rain chances for our
area Thursday right on into the start of next weekend. Entire period
will likely not be a washout...but simply too much uncertainty to
try to pinpoint a dry period. Of course...given recent (and coming)
wet pattern...will have to closely monitor rain possibilities. As of
now...guidance suggests a weakening/occluded system as it passes
overhead...keeping rainfall rates and totals at a minimum. Finally
..system backside cold air advection looks substantial enough to keep inherited
not entirely liquid precipitation Friday night into Saturday across
the far north (remember...just the messenger here). Speaking of
those temperatures...while don't see readings straying exceptionally
far from normal...overall flavor continues to support a tendency for
slightly below average readings. Of course...exact numbers will be
entirely dependent on system timing/rainfall coverage/and low level
frontal placement....which...my friends...are a long way from being
Aviation...(for the 06z tafs through 06z Sunday night)
issued at 123 am EDT sun Apr 20 2014
Summary: a cold front will stall over northern Michigan overnight
and through the day on Sunday with deteriorating flying conditions
Restrictions: overall..conditions looking a little more optimistic
for the day Sunday than six hours ago based on evening model
expectations. Only terminal impacted through early Sunday should be
pln...with a deterioration to MVFR/IFR restrictions by daybreak with
rain developing. Expect that it will take most of the day for this
rainfall to make it far enough south the impact the other
terminals...likely not until after 18z tvc/apn and even later at
mbl. Some MVFR restrictions due to ceilings and vsybs likely at these
sites by Sunday evening...with mbl still looking to hold onto VFR
conditions through 06z Monday.
Winds: southeast winds will continue 5-10kts for the overnight.
Winds will veer southerly by Sunday morning around 10kts before
continuing to veer southwesterly 10kts for the day on Sunday.
Sunday evening winds will diminish to light and variable.
Low level wind shear /confidence: high/: southerly winds in the 0.5-1.5kft layer are
now reaching 30-35kts and this low level wind shear will continue through the overnight
with shear layer winds gradually veering more southwesterly by
Sunday morning. Expect shear layer to mix out during the morning
Thunder: no threat this cycle.