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 261717
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
117 PM EDT THU MAY 26 2016

.UPDATE...
Issued at 1125 AM EDT Thu May 26 2016

Low clouds continue to fill in across all of Nrn Michigan late
this morning north of the approaching warm front. Wave of
overnight convection has pushed well east of our CWA...right in
time for our next wave of convection lifting NE out of Wisconsin
toward Nrn Michigan just ahead of the warm front. This area of
precip has shown an overall diminish in both areal coverage and
intensity over the last few hours...but expect both should ramp
back up again as we head into the afternoon thanks to diurnal
heating and increasing daytime instability. Big question is just
how much instability will we be able to realize given increasing
low level cloudiness which will limit diurnal instability. If we
are able to develop some good breaks in these clouds...CAPES
should reach to around 2000 joules this afternoon...certainly
enough for descent convective development. Will certainly keep
increasing chance pops in the forecast for the afternoon...
especially across North Central and NE Lwr Michigan where lake
breeze development off of Lake Huron lends to better low level
convergence with SW low level synoptic flow. Potential for
marginal svr storms will likely depend to a certain extent if we
break out of the low clouds and achieve better diurnal
instability. At this point...we certainly cannot rule out a few
stronger storms with some shear thru the column.

UPDATE Issued at 738 AM EDT Thu May 26 2016

Some aspects of the forecast today are worth re-evaluating.
Nighttime precip is departing largely on schedule, maybe a bit
ahead of schedule. However, we have an upstream MCS now pushing
into western WI, which has held together better than expected
several hours ago. There are a multitude of model solutions, from
the Nam (which doesn/t know the MCS exists), to the SPC HRRR
(which lets it slowly die across central/northern WI), to the RAP
(which slowly but steadily brings it all the way into northern MI
this afternoon).

The most likely scenario is that the MCV associated with upstream
convection will manage to carry some dying SHRA into parts of nw
lower MI as we approach or go past midday.

Earlier forecast did not have any precip near Lake MI. Will add
some pops to parts of nw lower MI beginning midday, and will add
some cloud cover there as well. Max temps could use a slight
downward tweak in response. Does this reduce the chance of any svr
TSRA this afternoon? It might, but the obvious incoming MCV will
provide a shot of dynamics that was not earlier anticipated. For
now will leave the HWO unaltered.

&&

.SHORT TERM...(Today and tonight)
Issued at 346 AM EDT Thu May 26 2016

High impact weather potential: a few severe t-storms possible
this afternoon/evening in northern lower.

A warm front continues to slowly work northward into lower MI,
presently north of TVC and near HTL. This front should make the
Straits area today, maybe even clear it for a time, before low
pressure departing across northern Quebec helps drag it back
southward tonight. A nw-se oriented band of shra is moving into
eastern upper and n central lower mi, supported by broad
warm/moist advection but with overall waning instability.
Isolated shra/tsra activity is seen ahead of this band. Forecast
remains on the messy side, with precip trends the main concern.

Today...shra/tsra will continue to lift ne-ward across northern MI
this morning. Much of this activity will have wound down/exited by
12z/8am, with eastern upper/ne lower MI likely to see at least some
activity lingering a bit past that. Tricky cloud forecast behind
this. Central and northern WI has plenty of stratus/fog, but we
have almost no low clouds to speak of. Though ongoing precip
event may help generate some, we may not have enough time to
develop much before sun starts eating away at them. That said,
will be difficult for eastern upper MI to not have lower clouds
this morning (and perhaps longer), given the warm/moist pattern
and prevalence of marine influences. In northern lower, expect a
period of clearing behind precip band, rather quickly giving way
to cumulus development as temps rise into the 70s with dew points
in the lower 60s.

Sw 950mb winds are 10-15kt, low enough to allow for some lake breeze
development, but not like the bonanza we saw yesterday. That will be
one possible trigger mechanism to take advantage of a reasonably
healthy amount of instability. The Nam is much too aggressive;
more reasonable progs from the Sref-Mean and GFS advertise MLCape
in the 1-1.5k j/kg range. That is more than yesterday. We also
have more shear than yesterday, with 0-6km bulk shear of 30-35kt.
This is not overwhelmingly favorable, but not terrible. We
managed one severe storm yesterday (right on top of HTL), and
suspect we have the ingredients to get a few today. Not a major
outbreak by any stretch, but enough for a moderately busy
afternoon/evening. CIPS analogs suggest a 30-40 percent chance of
at least one svr here.

Sct afternoon/evening pops will be placed away from the Lake MI
shadow in northern lower. Will keep most other areas dry, though
far western Mackinac Co could see some spillover from decaying
convection in western upper MI late in the day.

Max temps from near 70f/lower 70s in eastern upper MI, to lower 80s
in much of northern lower.

Tonight...diurnal convection from the afternoon will fade out by
late evening. With little in the war of forcing, and the primary low
level jet pointing at southern Lake Mi, don/t anticipate something
new firing here overnight. Could we have enough low-level sw flow to
generate new convection over the Lake Mi cold dome, and/or support
MCS remnants as they try to move in from the west? Either scenario
is plausible; neither is one that the NCAR or NSSL hi-res ensembles
are terribly excited about. Think regardless that precip coverage
will not be impressive, if it even happens at all. Am so not a fan
of 20 pops (i.e. slight chance), but that/s what we and our
neighbors are already carrying, and will let that ride thru most of
the night in most areas. Will also allow for some fog overnight.
Min temps mid 50s to around 60f.

.LONG TERM...(Friday through Wednesday)
Issued at 346 AM EDT Thu May 26 2016

(5/27)Friday...Ridging at 500 mb begins to move a little more north
and east of the forecast area, putting us in the weak part of the
jet streak off to the west. Meanwhile, the sfc low looks to try and
move to the east into the Upper Great Lakes, at least on the ECMWF,
while the GFS is more to the west, in the Dakotas. Lower Michigan
looks to be in the warm sector, and with the weak 500 mb jet, and
difluence, the thunder chances increase through the morning and into
the afternoon. As noted earlier, with so much of the dynamics to the
west, like on the GFS, and once we lose the heat of the day, think
that our chances are just that, chances, instead of likely it was
during the day and evening hours. ECMWF is a little more bullish
with the sfc low and would continue with the rain showers, and
thunderstorms in NW Lower, and portions of E Upper.

(5/28)Saturday...Again we run into the same issue as we had for
Friday`s forecast, only this time, the models are a little closer,
with the sfc low to the west, as well as the 500 mb trough. So as
the trough moves closer, and the sunshine begins to destabilize
things, the chances for thunderstorms will go up through the day. Of
course, this looks to diminish once we lose the heat of the day and
the 500 mb shortwave trough rotates through the region, and the 700-
500mb layer dry slot begins to help cap off the convection during
the evening and overnight.

Extended (Sunday through Wednesday)...Low confidence pattern this
week with the ECMWF and the GFS at odds with the forecast after
Monday. The 500 mb shortwave trough moves through the Upper Great
Lakes so that Sunday has showers and thunderstorms, and it ends up
dry over N Lower Sunday night.  Models continue to look dry into
Monday night, although GFS has some qpf splattered about during the
day. Tuesday, both models start with 500 mb ridging in the Upper
Great Lakes, so that the day probably ends up dry. However, going
into the evening, the ECWMF pushes a 500 mb trough into the region,
while the GFS amplifies the ridge a bit and keeps the low (now a cut
off) back farther west. This remains the case through Wednesday as
the ECMWF says rain and the GFS is dry.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 117 PM EDT Thu May 26 2016

Scattered showers and thunderstorms will redevelop across Nrn Lwr
Michigan later this afternoon and this evening as CAPES increase
to near 2500 J/kg thanks to diurnal heating. Modest wind shear
thru the column could produce an isold strong/marginally svr
storm. The best chance of precip will be across North Central and
NE Lwr Michigan...including APN. Will handle with VCTS for a
portion of the afternoon and early evening. Will leave the rest of
our TAFs (PLN/TVC/MBL) dry for now and update if needed.
Southerly winds around 10 kts this afternoon will become
light/variable tonight and then shift to the SE on Friday.

&&

.MARINE...
Issued at 346 AM EDT Thu May 26 2016

Humid pattern with generally light southerly flow will persist.
This will maintain fog at times over the chilly waters of the
Great Lakes. Small craft advisories will not be needed in the near
future. Sporadic chances for showers and t-storms continue,
especially very early this morning.

&&

.APX Watches/Warnings/Advisories...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

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


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