Area Forecast Discussion
Issued by NWS Gaylord, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KAPX 152021
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
321 PM EST Sun Jan 15 2017

.NEAR TERM...(Tonight and Monday)
Issued at 322 PM EST Sun Jan 15 2017

High impact weather potential...none.

1031mb high pressure is positioned along the southern border of MI.
Sub-850mb winds continue to become more southerly. Lake clouds
continue to become more expansive along an old land-breeze
convergence boundary over northern Lake MI.  These are spilling into
parts of nw lower MI, and especially the Straits area and eastern
upper. Cloud/temps trends are the main concern into Monday
afternoon, as precip looks to hold off until just after.

Tonight...stratocu deck from eastern upper MI to the Gd Trav Bay
area will continue to progress slowly eastward. This deck should
thin out and erode as it does so, as it moves away from Lake MI and
as diurnal heating wanes. Otherwise another quiet night ahead, with
some cirrus starting to drift into southern sections overnight.
Pressure gradient is tighter than last night, especially in northern
sections. Expect temps near 20f in eastern upper MI, and along the
nw lower MI coast. However, in the rest of northern lower, am
concerned we will have at least a period of decoupling. Readings
here should range down into the lower/mid teens.

Monday...nearly stacked low will lift from northern OK to nw MO.
Increasing warm/moist advection will thicken/lower cloud cover from
south to north during the day, especially in the afternoon. Virga
will erode low-level dry air in southern sections as the afternoon
proceeds. However, it will be a challenge to actually get precip to
the surface. Since yesterday, the Nam and GFS have changed stories,
with the Nam now dry and the GFS arguing for precip to work in very
late. Will maintain a small chance for precip, only after 4 pm, and
only in parts of Manistee Co. If this actually occurs, it precedes
the warm nose aloft, and so p-type will depend on how warm the
surface layer. Given expected temps in the mid 30s, a chance of
either snow or rain is reasonable.

Max temps in the mid 30s.

&&

.SHORT TERM...(Monday night into Wednesday)
Issued at 322 PM EST Sun Jan 15 2017

...Wintry mix leading to hazardous travel Monday night-Tuesday...

High Impact Weather Potential: Icy wintry mix expected Monday night
through midday Tuesday. Hazardous travel possible.

Pattern Forecast: Upper-level low and associated surface reflection
currently centered over northern Mexico/southern NM will eject
northeastward out of West Coast troughing on Monday resulting in
ridging across the Great Lakes before low pressure rolls across the
region on Tuesday. Strong warm air advection aloft will be ongoing
across the region Monday night-Tuesday all while deep layer moisture
slowly advects into the area from the south. However, boundary layer
dry air should keep most, if not all, precip at bay until Monday
evening/night.

Primary Forecast Concerns: Main forecast concerns and challenges
revolve around Monday afternoon through midday Tuesday and include
timing of precip arrival, ice accumulation amounts, and if/when a
transition to all rain occurs Tuesday. Cloud cover will certainly be
on the increase late in the day Monday, but not before a majority of
the area begins the day to the tune of "calm before the storm" with
mostly to partly sunny skies. Thickening/lowering clouds will be the
rule late in the day, most prevalent during the late afternoon/early
evening, as top down saturation gets underway. While a bit of
scattered precip may work its way into the far southwest (Manistee,
Cadillac, etc.) during the evening hours, guidance has slowed a bit
from 24 hours ago, with the most predominant surge of moisture
arriving overnight into Tue. afternoon (~06-15z), in conjunction
with the tightest thermal gradient and push of warm air aloft. There
still lies some uncertainty in terms of initial p-type as boundary
layer temps remain above freezing after a `mild` Monday. With a
wedge of dry air sub 700 mb, wet-bulb temps are progged to be in the
-1 to 0 C range, and suspect that will be the largest player in
terms of p-type at the onset. Will initially allow for at least a
brief period of wet snow prior to the warm nose arriving from south
to north. Glaring concern with this theory is that top down
saturation isn`t able to overcome the aforementioned dry wedge until
the tighter thermal gradient pushes north, which would result in
precip beginning as more of a sleet and rain/freezing rain mix.

Either way you slice it, as heavier/steadier precip arrives
coinciding with the warm nose arrival, rain/freezing rain is
expected to become the predominant p-type through a majority of the
overnight hours into Tuesday morning across much of northern Lower.
Note that several of the 15/12z deterministic models have trended
surface temps about 0.5-1.0 degree F warmer (all the difference, in
this case). Not completely sold enough on that theory at this point
to run with it full throttle (which would switch precip over to
plain rain across many areas excluding the higher terrain/northeast
Lower) after only a couple hours of freezing rain. Slow-to-arrive
precip and slightly cooler boundary layer temps north of the bridge
may inhibit much precip from falling until Tuesday morning for,
likely continuing in more scattered fashion Tuesday afternoon as a
wintry mix of snow, sleet and freezing rain. Not much change from
prior thinking in terms of ice accumulation amounts with 0.05-0.15
inches across interior northern Lower, resulting in hazardous
travel. Downsloping should lead to just a touch warmer overnight
temps as you head close to Lake Michigan, so expecting lesser
amounts in those locales (but even a glaze can be a travel headache
on non-pretreated roadways). Lingering freezing rain issues Tuesday
should gradually wane as temperatures begin to rise above freezing
from south to north. Last to warm will be across the U.P., where
precip may remain mixed for a large part of the day. PoPs decrease
Tuesday afternoon, although some lingering drizzle may plague parts
of the area...perhaps even mixed with light snow/flurries as
boundary layer temps begin to cool just a touch Tuesday night.

In terms of headlines, if the current trends continue we`ll be in
advisory territory. In coordination with neighboring offices, will
hold off this forecast cycle for another look at tonight`s
runs...just to make sure there isn`t a substantial jump in one
direction or another.

&&

.LONG TERM...(Wednesday night through Sunday)
Issued at 322 PM EST Sun Jan 15 2017

High Impact Weather Potential: Weekend rain possible. Could see
slick roads overnight, but a few warm days prior could lessen the
impact.

Things look pretty quiet from mid-week into the weekend, with precip
likely ending by Wed afternoon. The big story will be the well above
normal temps through the period, as temps moderate from the upper
30s Wed to as high as the mid 40s by the weekend. Normal highs this
time of year are in the mid 20s.

With a system passing to our west over the weekend, can`t rule out
some warm advection showers. At this time, most model soundings are
showing thermal profiles supportive of all rain. Have adjusted p-
type over the weekend in collaboration with surrounding offices to
reflect this.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1231 PM EST Sun Jan 15 2017

Mostly VFR, except for periods of MVFR this afternoon.

High pressure over the southern lakes will move gradually east.
One last bit of lake effect cloud cover (before warmer air
arrives) has blossomed over northern Lake MI. This will bring MVFR
cigs for a period this afternoon at all TAF sites except APN.
Otherwise, just cirrus expected into Monday morning, with clouds
then lowering and thickening as the day proceeds.

A light sw wind will persist.

&&

.MARINE...
Issued at 322 PM EST Sun Jan 15 2017

Southwest winds will continue into Monday, but generally on the
light to moderate side, as high pressure moves away from far
southern lower MI. Winds will back to the se Monday night, as low
pressure moves nne-ward from Missouri.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

NEAR TERM...JZ
SHORT TERM...MJG
LONG TERM...ALM
AVIATION...JZ
MARINE...JZ



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.