NWS Gaylord, MI wrote its last area forecast discussion before the first event at May 28, 12:34 PM EST, 6 minutes earlier.
Area forecast discussion, May 28, 12:34 PM EST, 6 minutes before
Area Forecast Discussion
National Weather Service Gaylord MI
134 PM EDT Thu May 28 2020
.UPDATE...
Issued at 1001 AM EDT Thu May 28 2020
A slow-moving cold front is pushing across eastern Superior,
central upper MI, and ne thru sw WI. Moist southerly flow is found
ahead of the front, including the remnants of Bertha in eastern
OH and western PA. Some precip is found in northern MI, including
light showers near OSC/W Branch/Gladwin, and a cluster of more
vigorous convection in the CVX/PLN area. This latter cluster has
had a little in-cloud lightning this morning, per the ENTLN.
However, the most widespread precip is with and just behind the
front.
A little different day ahead today than the last few, with plenty
of cloud cover to limit diurnal heating. There are some breaks in
the clouds in eastern upper MI, though thicker clouds and showers
are encroaching from the south. There are also breaks working
northward into w central lower MI. But we are very moist thru a
deep layer, and any open spots in cloud cover will tend to quickly
fill in with clouds and showers.
That said, enough diurnal heating will occur to generate skinny
MlCape values of circa 500j/kg. (Note that per the 12Z APX
sounding, we are already cooler in the 750-400mb layer than even
12 hours ago.) With skinny cape and limited evap cooling potential
in the column, don't think we will see the isolated svr threat we
saw occasionally this week. Heavy/excessive rain is a bigger
concern. 950-850mb s/ssw winds of 15kt or so isn't amazing, but
will interact with outflow boundaries to regenerate convection and
potentially produce training.
Precip coverage/intensity should increase after 1 pm. This will
likely be initially along a TVC-PLN-Raber line, migrating east
thru the afternoon to HTL-APN. Localized 1-2" rainfall amounts
will occur, and perhaps 2"+ in a few spots. Expected amounts will
be highest in nw and n central lower MI, on into far eastern upper
MI. Thankfully, for now this does not include areas near Saginaw
Bay, which is clearly the most vulnerable part of this forecast
area with respect to flooding.
Will closely monitor precip trends today. A flood or flash flood
watch is worth some consideration, but am choosing to hold off for
now.
Have boosted max temps by 1-2f, mid 70s to low 80s.
&&
.NEAR TERM...(Today through Tonight)
Issued at 323 AM EDT Thu May 28 2020
...Widespread showers and a few thunderstorms...
High impact weather potential: Locally heavy rain possible.
Pattern synopsis/forecast: Persistent upper level pattern of late
beginning to break down as closed southern low begins to lift
northeast and strong northern stream energy digs southeast across
the Prairie lands of southern Canada. Overhead mid level heights
showing signs of falling as a result, although deep southerly flow
ahead of weak surface trough/cold front continues to pump
unseasonably warm and moist air into the Northwoods. Most active
weather early this morning tied to that front across Wisconsin down
into the Corn Belt, with more disorganized showers across our area
as weak wave rotates overhead.
Much more bonafide changes expected in the coming days, driven in
large part by that southern Canada wave as it deepens and digs
steadily southeast...reaching central upper Michigan and Wisconsin
by Friday morning. Upstream cold front will strengthen and increase
its forward speed in the process, likely clearing our area by later
this evening or early Friday morning. Combination of increased low
level convergence, mid and upper level support (the latter supplied
by some decent right entrance region jet dynamics), and deep
moisture all support a pretty good bet for showers and thunderstorms
today and tonight.
Primary forecast concerns/challenges: Temporal and spatial
resolution of showers/storms through tonight as well as addressing
additional rainfall amounts.
Details: As mentioned above, plenty coming together to produce
plenty of showers today into at least this evening. Plume of even
deeper moisture rotating north around that southern wave will only
help the cause, helping drive precipitable water values to well over
an inch and a half. Plenty of clouds will keep instability limited
when compared to the last few days, but still enough to warrant at
least some thunder potential. Despite that strengthening front and
enhanced deep layer support, not seeing any real severe weather
concerns given that limited instability and weak mid level lapse
rates. "Skinny" cape profiles and deep moisture through the entire
vertical column support some pretty efficient rain generation
processes...supporting at least brief periods of heavier rain,
especially with any embedded thunderstorms. Best shower/storm threat
gradually ends from northwest to southeast tonight as that front
sweeps across the area. Could see some decent rainfall totals by
Friday morning, with some area likely seeing over an inch of
rain...with locally higher amounts definitely possible. Area remains
under slight risk of excessive rain...per latest Weather Prediction
Center forecast. Definitely something to monitor today and tonight.
As for temperatures...clouds and showers will keep readings at least
a few degrees cooler today than the past few days, with highs
generally in the 70s. Definitely turning a bit cooler tonight, with
lows ranging from the middle 40s to upper 50s (warmest south side of
the sunrise side).
&&
.SHORT TERM...(Friday through Saturday)
Issued at 323 AM EDT Thu May 28 2020
High Impact Weather Potential: Frost/freeze potential Saturday night
Pattern Synopsis:
Longwave troughing centered over the Great Lakes will slowly pivot
across the NE CONUS through the weekend with embedded jet maxima
rotating through at times. At the surface, a cyclone near James Bay
will continue to deepen underneath divergence/ascent aloft and
progress across Quebec. With upper-level ridging in place across the
Rockies, surface high pressure will build across much of the north-
central CONUS underneath subsidence aloft at the ridge/trough
inflection point.
Forecast/Details:
A cold front associated with the cyclone in Canada will have moved
through the area by the start of the period. However, lingering
showers are possible Friday morning, especially across our far
southeastern counties that have already experienced heavy rainfall
in May thus far. Mainly light rainfall is expected Friday morning as
the heaviest is expected to fall before the period begins. However,
effects of any flooding as a result of this rainfall -- especially
areas of locally heavier amounts due to training storms -- will be
felt through Friday with the given antecedent ground/soil conditions.
After Friday, the focus shifts to Saturday night as cold air is
funneled into the Great Lakes with enhanced NW surface flow created
by the departing cyclone to our northeast and surface high pressure
building to the west. This cold, dry airmass will favor clear skies
Saturday night with accompanying weak winds as high pressure settles
overhead. While this is still several days away and don't want to
get too far ahead of ourselves, this set-up has the potential to
tank overnight low temperatures down to near freezing across much of
northern lower Michigan away from the lakeshore, and even into the
upper 20s for some. These low temperatures certainly bring the risk
for frost and even freeze conditions across the area. More details
will come as Saturday night draws closer and confidence increases.
For what it is worth, record lows Saturday night are in the upper
20s. Aside from Saturday night, high temperatures will drop into the
60s for many behind the cold front on Saturday as cold air advection
helps keep temps lower throughout the day. Highs drop even further
on Saturday as many areas will struggle to get warmer than the mid
50s during the afternoon -- quite the difference from the mid-summer
high temps as of late.
.LONG TERM...(Saturday night through Wednesday)
Issued at 323 AM EDT Thu May 28 2020
High Impact Weather Potential: More frost concerns Sunday night
Amplified longwave troughing will continue to pivot off of New
England into early next week while upper-level ridging moves into
the central CONUS. The Great Lakes looks to stay in persistent NW
upper-level flow into the middle of next week. Relatively strong
surface high pressure will be centered over the Great Lakes through
the beginning of the work week as it slowly builds into the mid-
Atlantic. This will inhibit the return flow of warm, moist air back
into the region for a few days. Embedded shortwaves/speed maxima in
the large-scale flow may help support some precip chances towards
the end of the long term as high pressure begins to vacate the
region. While most of the long term appears somewhat quiet for now,
the main concern may be continued frost conditions that will be
possible again Sunday night as lows may get down into the mid 30s
across northern Michigan. However, these colder temps will give way
to afternoon highs in the low 70s early next week with overnight
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 133 PM EDT Thu May 28 2020
Periods of showers/storms into tonight.
Showers and thunderstorms are already present in numbers across
northern MI, and will remain so until after a cold front finally
crosses the area tonight. MVFR to IFR conditions will persist
until Fri morning, when we will improve to VFR from west to east.
IFR cigs will be most common tonight.
Light sw breezes this afternoon, becoming nw tonight into early
Friday.
&&
.MARINE...
Issued at 323 AM EDT Thu May 28 2020
Cold front will making steady southeast progress across the region
today into tonight, bringing showers and a few thunderstorms along
with it. Southwest winds will turn northwest after the front passes,
becoming a bit gusty at times, especially on Friday. Still appears
both winds and waves will remain mostly below advisory levels,
although cannot rule out a few gusts to advisory levels on Friday.
Northwest to north winds this weekend will usher in a much cooler
and drier airmass.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
UPDATE...JZ
NEAR TERM...MB
SHORT TERM...DJC
LONG TERM...DJC
AVIATION...JZ
MARINE...MB