Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kapx 150550 

Area forecast discussion
National Weather Service Gaylord Michigan
150 am EDT sun Sep 15 2019

Near term...(today through tonight)
issued at 147 am EDT sun Sep 15 2019

..a bit of wet weather to end the weekend...

High impact weather potential: minimal. Perhaps a rumble or two of
thunder, especially early this morning.

Pattern synopsis/forecast: amplification process to the mid and
upper level flow regime across noam beginning to take shape early
this morning, made to do so by robust Pacific originated upper level
jet core punching into the southern Canadian rockies. Mid level
response is one of building Western Heights, with subtle height
rises already noted into the western High Plains. Northern Michigan
centered in transition axis between this burgeoning upstream ridge
axis and elongated troughing centered across northeast noam. Low
amplitude shortwave trough traversing the resultant mostly zonal
flow aloft, cutting across the western Great Lakes early this
morning. Attendant and quick hitting round of warm, moist advection
on nose of 30+ knot low level jet directed into the area, kicking
off some showers and a few rumbles of thunder in the process.

Amplification really kicks into overdrive today and tonight as that
earlier mentioned upper jet core bows well north into central
Canada. Mid level heights continue to build north in the process,
with the development of an elongated and robust upper level ridge
axis, extending from central Canada to the Gulf of Mexico by sunrise
Monday. Approaching shortwave trough is forced southeast across our
area quicky this morning, with perhaps even more subtle
perturbations passing overhead heading through this afternoon and
evening. These will act to keep our weather a bit inclement and cool
to end this weekend, with warmer and more quiet weather soon to
follow as that upstream ridging eventually builds overhead (see that
information in the short and longer term section to follow).

Primary forecast concerns/challenges: shower trends and potential
for a bit of fog tonight.

Details: main bout of wet weather will occur early on this morning
as nose of low level jet and core of primary warm, moist advection
spread overhead. Recent radar trends confirm latest high res
guidance output of two primary axis of rainfall, one cutting across
the northern third of the area, with the other well to our southwest
across northern Illinois. Just enough elevated instability to
support a rumble of thunder or two, but definitely nothing
significant. While main support for rainfall exits stage right
quickly this morning as shortwave trough does the same, guidance
derived soundings show plenty of lingering low level moisture,
suggesting clouds will be much harder to erode. Moisture depth may
be just deep enough to kick off a bit of drizzle/spotty very light
rain showers into this afternoon, but believe most areas remain rain-
free after this mornings activity. Those low clouds look to hang on
into much of tonight with little mixing or dry air advection noted
in the surface-rooted moist layer. May even see some fog develop
overnight as the boundary layer cools, likely most significant
across eastern upper and The Highlands of northern lower.

As for temperatures...clouds will definitely put a lid on how warm
we get today, with highs expected to be near normal. And,
those clouds will keep things on the mild side tonight, with
expected lows in the 50s several degrees above normal for this time
of year.


Short term...(monday through tuesday)
issued at 147 am EDT sun Sep 15 2019

..mild and mostly dry...

High impact weather potential: minimal

Pattern/synopsis: broad scale high pressure in the southeast
Continental U.S. Has pushed the mostly zonal jet near the US-Canadian border.
A wave currently over The Arrowhead of Minnesota will bring rain and
thunder chances through Sunday. By Monday morning, however, this
wave will have moved well off to the east. Ridging will be
building into the central US and will stretch well north into
Canada. This anomalously strong ridging for this time of the year
will last through most of the week, giving US above normal
temperatures for mid-September.

Forecast details/concerns: Monday morning we still might be hanging
on to some very light scattered showers and low level clouds as most
guidance has the column saturated from 900mb to the surface. A ridge
of surface high pressure and drier air quickly moves in after noon,
giving way to mostly sunny skies and highs in the low to mid 70s.
Off to our west a surface low intensifies in the northern rockies.
The elongated surface high is very slow to move through southern
Ontario/Quebec, and will thus continue to dominate our weather for
tuesdsay. This high keeps the northern rockies low from making much
eastward progress. One thing that could bring a very low chance of
rain (more likely just renewed cloud cover) would be a subtle
shortwave trying to ride over the top of the ridge. Included some
very low pops in eastern upper because of this.


Long term...(tuesday night through saturday)
issued at 147 am EDT sun Sep 15 2019

High impact weather potential: minimal

Midweek continues the strong ridging with the ridge axis moving
right overhead of the upper Great Lakes. This will lead to a fairly
dry pattern with high temperatures being a good 10 to 15 degrees
above normal for mid-September. Slight rain chances move back into
the picture late week as a low treking across Ontario drags a weak
cold front across the state. Guidance is trying to come into a
little better agreement with the front moving through on Thursday.
But placement and timing confidence in this system is still low
enough to warrant low-end pops late Wednesday into Thursday. Then
Friday into the beginning of the weekend looks dry as weak high
pressure again expands back westward over the area (from the main
core of high pressure over the eastern seaboard). This is quickly
followed by another system lurking off to the west.


Aviation...(for the 06z tafs through 06z Sunday night)
issued at 1143 PM EDT Sat Sep 14 2019

IFR cigs to develop late Sunday.

Ridge of high pressure will move off to the east. This will allow
an incoming warm front and upper level disturbance to push into
Michigan. Showers (and perhaps a few T-storms) will occur overnight
into Sunday (especially early). MVFR to IFR conditions will
develop as precip moves in. Even as widespread precip exits
Sunday, IFR cigs will develop.

A southerly breeze develops Sunday. Low level wind shear at tvc/mbl late tonight
and early Sunday morning.


issued at 147 am EDT sun Sep 15 2019

Southeast winds expected to be a bit gusty this morning,
especially across Whitefish Bay. Some low end Small Craft Advisory
gusts are possible, and will continue to monitor for potential
headlines. Winds decrease in speed this afternoon, with light winds
expected tonight. Trends support sub-advisory winds persisting
through at least Tuesday night.


Apx watches/warnings/advisories...


National Weather Service Glossary of Abbreviations