Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 200750

Area Forecast Discussion
National Weather Service Gaylord MI
350 AM EDT Thu Oct 20 2016

.SHORT TERM...(Today and tonight)
Issued at 350 AM EDT Thu Oct 20 2016

...Return of cloudy skies and cooler temperatures...

Overview: Progressive short wave trough making its way through the
plains and into the Midwest/western Great Lakes region this
morning. Fairly tight thermal gradient and resulting strong upper
jet streak stretches from the midwest up through the Great Lakes
into eastern Canada. Elongated surface low/front continues to
develop from the Ohio Valley back through Arkansas with a long
axis of showers/thunderstorms north of the front stretching from
Ohio into north Texas. Another small grouping of showers/storms
noted over eastern Kansas into Iowa near the vorticity center and
upper level cold pool.

Here at home, Secondary cold front has made it through northern
lower Michigan and into the Saginaw Bay area with little fanfare.
However as anticipated, low stratus has been making steady
progress south through northern Michigan behind the front with
the shallow cool air seeping into the region. Some lake banding
evident on Superior per satellite fog product and a little bit of
lake precip just starting to show on Lake Superior per MQT radar.

Today and tonight: Plains short wave will continue to carve out
deeper troughing through the Great Lakes/Midwest and Ohio Valley
while noticeably cooler air spreads into northern Michigan.
Surface system to the south will slide up through the Ohio Valley
and into New England/mid Atlantic coast by Friday morning. Most
precip with this system will miss northern Michigan, although
northern fringe may just skirt the far SE counties as the system
digs and pivots eastward. Will carry some low end pops for showers
across those areas today.

Meanwhile, cold advection will persist through tonight with H8
temps dipping to just below 0C by evening and several degrees
below 0C by Friday morning (-6C forecast of northern Superior).
Certainly enough instability to talk lake effect precip. But there
are some negatives in the form of some fairly dry air aloft and
relative low inversion heights, although lake effect conditions do
improve a bit tonight into Friday as cold advection proceeds.
Best chances for lake induced rain showers will be across upper
Michigan today and translate into parts of NW lower Michigan
tonight. I do not anticipate particularly well organized or
vigorous lake effect rain showers given the above negatives.

.LONG TERM...(Friday through Wednesday)
Issued at 350 AM EDT Thu Oct 20 2016

High Impact Weather: Waterspouts Friday on the Lakes

(10/21)Friday...With the fall season, the forecast grids become more
complicated as the chance for lake effect processes begin to factor
into the forecasts. From Fri/12z to Sat/12z for the forecast, is no
different with the models starting out relatively similar, but
beginning to diverge by the end of the period with the moisture
parameters so that there is a decent chance that the LE rain
overnight will end much more quickly than all the offices have
depicted. The problem is that the Model (GFS/NAM/ECMWF/HiRes) all
begin to dry out the 850-700 mb layer at different rates, and with
us in the early part of the fall lake effect season, the rain seems
to be more affected by dry air, and does snow. So the main idea is
that the North to NNW flow areas will be affected in the morning and
then as the 850 mb temperatures warm a bit, and the moisture in the
850-700 mb layer dries to around 40% on the GFS, (30% on the NAM)
the rain should begin to taper off with it halting overnight (maybe
in the evening).

(10/22)Saturday...High pressure builds into the region, and the warm
air moves in as well, but the baroclinic zone is rather broad, and
with 500 mb jet streak to the west. So no precipitation is expected
as temperatures begin to warm up during the day, and somewhat

Extended (Sunday through Wednesday)...The pattern is evolving into a
warmer than normal with near normal precipitation as the almost
zonal flow at 500 mb begins to amplify in the Central US in response
to the 500 mb lows in the N Pacific and N Atlantic. However, with
the flow still rather progressive several shortwave troughs move
through the flow, bringing showers to the Upper Great Lakes every
couple of days. The flow begins to flatten out a bit more after


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1153 PM EDT Wed Oct 19 2016

MVFR cigs at times overnight/Thu morning.

Lower cigs are making slow southward progress into northern lower
MI, behind a cold front crossing the region. MVFR cigs are
expected to expand into all taf sites during the overnight, and
last until about midday Thu. Could see a few lake effect rain
showers Thu evening, especially in the TVC area.

Light northerly breezes thru the forecast.


Issued at 350 AM EDT Thu Oct 20 2016

Northerly winds will prevail on the lakes today through Friday
with occasional gusts into the 20 knot range and waves building
into the 2 to 4 foot range. Marginal small craft advisory
conditions may be seen on Lake Michigan and Lake Huron late today
through Friday, but will not hoist any marine headlines at this

Otherwise, with increasing over lake instability, waterspouts
will be possible on Lake Michigan tonight into Friday, and
possibly on Lake Huron on Friday.




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