Area Forecast Discussion
Issued by NWS Gaylord, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 231724
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
124 PM EDT TUE AUG 23 2016

.UPDATE...
Issued at 1006 AM EDT Tue Aug 23 2016

No sooner do I post the previous update, than a few showers flared
back up over eastern upper MI. Forecast updated for isolated
showers for another couple of hours up that way.

UPDATE Issued at 853 AM EDT Tue Aug 23 2016

Early morning shower activity was (as expected) done for good by 8
am. Some bubbly mid-clouds linger from Harrisville to Standish,
and more extensively in parts of Chippewa Co. This will tend to
erode with time, though it will take several more hours before
central/northern Chip loses the mid-cloud deck. With a warmer but
still relatively dry airmass advecting in on sw winds, our cu
field should be less impactful than yesterday.

So overall, quiet for the rest of the day. Warm max temps, near
80f to the mid 80s.

&&

.SHORT TERM...(Today and tonight)
Issued at 339 AM EDT Tue Aug 23 2016

High impact weather potential: A minimal chance at a thunderstorm
through daybreak.

Pattern synopsis and forecast:

High pressure was over the east coast early this morning while low
pressure was in the Dakotas. Nrn Michigan in between these two
features with a tightening pressure gradient resulting in periodic
gusty SW warming winds. A weak shortwave aloft was crossing nrn
Michigan on the leading edge of steeper lapse rates aloft (6 c/km)
within an area of enhanced 925mb-700mb theta-e advection. Forcing
from the wave is supported by a region of upper divergence and has
resulted in an area of showers over nrn Lake Michigan and NW lower.
This rainfall was falling apart overhead, as it is running into our
drier air, and by out-running the stronger support being supplied by
an LLJ laid out in central upper.

The wave and theta-e advection pass by around daybreak with the LLJ
weakening and veering with time. This will result in the demise of
all rain showers and any minimal thunder threat. Mid level heights
then rise through the day with increased overall subsidence ahead of
a strong eastward-moving closed low spinning across srn Canada. Any
forcing from additional weak waves in the flow aloft, shift north
into Ontario, while PWATS/atmospheric moisture drop through this
evening. A relatively sunny day heading through this morning, and a
mostly clear evening.

Late tonight, the flow turns more SW aloft ahead of the spinning
closed low, with more defined/stronger shortwave energy punching up
through the mid/upper Mississippi valley and western Great Lakes.
Renewed 925-700mb theta-e advection tries to sneak into the Manistee
area at daybreak with no other forcing than DPVA in the picture.
Doubt there will be any possible rain to make it in by daybreak.

Most areas will see highs today in the low to mid 80s with lows
tonight in the lower half of the 60s.

.LONG TERM...(Wednesday through Monday)
Issued at 339 AM EDT Tue Aug 23 2016

(8/24)Wednesday...Models continue to slow the runs down
progressively over the last several days and are beginning to show
holes in the QPF. This has caused me to slow down the onset of the
rain and lower the pops a bit, so that we are in low likelys, and
not high likely/categorical. The ECMWF and NAM due has different
amounts for likely rain, so will keep the high chance to likely as
it seems that when the thunderstorms roll in most everyone will see
rain. 500 mb winds are pretty anemic (25 knots) so am not expecting
much in the way of a severe threat, there is some decent MUCAPE, but
it looks skinny, so again thunderstorms, but not likely severe.
after 00z, the rain should begin to leave the region, wouldn`t be
surprised if my timing is a little slow based on the HiRes models,
but the ECMWF/GFS shows the rain continuing through 06z, before
things begin to dry out.

(8/25)Thursday...The cold front stalls a bit, downstate, and allows
a wave or two to move up the front and produce some rain in NE
Lower, but the front begins to move out of the region overnight, as
the sfc high begins to build into the region. The 500 mb flow goes
zonal again, pushing the waves out of the region.

Extended (Friday through Monday)...As I have been saying the last
few days, the pattern is for a decent frontal passage every couple
of days and looks like it will continue on into the following week.
the models are in agreement that after Wednesday/Thursday passage,
that the next is Saturday/Sunday. The GFS suggests that there could
be more rain as the cold front stalls, kind of like the forecast on
Thursday. ECMWF dries things out on Monday. So we will see, keeping
the chance pops in the forecast for now.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 124 PM EDT Tue Aug 23 2016

VFR. Some showers arriving at MBL/TVC Wed morning.

Southwest low-level flow will continue, between high pressure
over mid-atlantic states, and a cold front in the plains. This
flow is initially dry, with limited cloud cover for much of
tonight. However, deeper moisture will start to edge toward the
region from the sw late tonight and especially Wed morning. Clouds
cover will increase in nw lower MI late tonight, and some showers
will arrive at MBL and then TVC Wed morning.

S to sw surface winds will persist, and will be gusty at times,
especially this afternoon.

&&

.MARINE...
Issued at 339 AM EDT Tue Aug 23 2016

A tighter SW flow pressure gradient continues to set up over the
nearshore waters. There are already several locales with advisory
level winds over Lake Michigan, and periodic advisory level winds
will become more common across Whitefish Bay and parts of the Lake
Huron nearshores through today. Lake Michigan will continue to see
these winds through at least tonight, and likely Wednesday. Will
keep current headlines only through tonight however. The gradient
loosens up later Wednesday and Wednesday night as a cold front
approaches with good chances for showers and possible storms.


&&

.APX Watches/Warnings/Advisories...
MI...BEACH HAZARDS STATEMENT through late tonight for MIZ015-016-019-
     020-025-031.

LH...SMALL CRAFT ADVISORY until 6 PM EDT this evening for LHZ345-346-
     348-349.

LM...SMALL CRAFT ADVISORY until 5 AM EDT Wednesday for LMZ323-341-342-
     344>346.

LS...SMALL CRAFT ADVISORY until 6 PM EDT this evening for LSZ321.

&&

$$

UPDATE...JZ
SHORT TERM...Dickson
LONG TERM...JSL
AVIATION...JZ
MARINE...Dickson


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