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Area forecast discussion 
National Weather Service Gaylord Michigan
414 am EDT Thursday Jul 30 2015

Near term...(today through tonight)
issued at 411 am EDT Thursday Jul 30 2015

..warm and windy today...

High impact weather potential: elevated fire danger...high swim risk
on Lake Michigan.

Pattern synopsis/forecast: midnight surface analysis shows
yesterday's cold front moving across southern Ontario/lower Great
Lakes...broad cyclonic flow behind the front across the upper
lakes/upper Midwest and northern Ontario/Manitoba associated with an
anomalous surface low near the southern shore of Hudson Bay. 1021mb
high centered over central portions of Nebraska/Kansas. Dew points
have fallen off nicely behind the boundary...00z precipitable water
values between apx (behind the front) and DTX (ahead of the front)
were 0.67/1.71 inches respectively. Water vapor imagery shows a
well defined vorticity center tracking east across central Upper
Michigan...pushing an area of middle clouds across eastern upper/far
northern lower Michigan along with some sprinkles moving through The
Straits. Another short wave trough was spinning east across
southeast Manitoba/North Dakota.

While low level cyclonic flow persists today...a couple of upstream
short wave troughs will cross the upper lakes over the next 24-36 arrives later this afternoon with a second approaching
Friday morning.

Primary forecast concerns: impacts of approaching short wave energy
(if any). Gusty winds and warm temperatures today leading to
elevated fire danger. High swim risk likely on Lake Michigan beaches

Today...looks like winds should pick up rather quickly this morning
with initial mixing...925mb winds already 25-30kts overhead so that
should get things going early on. Probably a sunny start but cooler
low level temperatures across Upper Michigan (e.G., 8-10c 850mb
temperatures) expected to result in quick development of a
stratocumulus field above the bridge by late morning. Short wave
trough over southeast Manitoba will be digging southeast across the
upper lakes during the afternoon hours...probably crossing the
forecast area during middle/late afternoon with an associated thermal
trough. Decent mixing won't be an issue...00z apx sounding residual
layer extends to 800mb so should mix out to at least that level.
Question is one of low level moisture...if surface dew points can
remain above 55f or so by middle/late afternoon as cooler middle level
temperatures arrive then perhaps there could be some thin
instability for short wave trough to act upon. Current thinking is
that low level moisture may fall a little short...especially if
upstream vertical moisture profiles from 00z grb/mpx are any
indication. So current dry forecast seems the best way to go at
this point...will have to watch this or the possibility of some
convection upstream across Wisconsin drifts into northwest lower
late in the day/early evening. Afternoon highs across northern
lower expected to reach into the 80s once again for the most
part...while across eastern upper expect afternoon highs in the 70s.
Rather sparse precipitation recently combined with another warm
afternoon and gusty winds expected to result in elevated fire danger.

Tonight...lead short wave trough will be moving through lower
Michigan during the first part of the evening...some weak low level
warm/Theta-E advection across Upper Michigan and maybe some elevated
instability. Will continue with the dry weather idea for the evening
though won't rule out some showers floating around in the vicinity
especially to the north. Second short wave trough/speed maximum will
drop into Lake Superior overnight...various bits of quantitative precipitation forecast in the
guidance but tough to square that up with the forecast mass fields.
So forecast persistence will be the way to go for now.


Short term...(friday through Saturday night)
issued at 411 am EDT Thursday Jul 30 2015

(7/31)friday...with the 500 mb low over James Bay, little spokes of
energy rotate over the region however, like yesterday, i'm not
completely sold on it. While there is a thin layer of moisture at
850 mb, the deeper moisture is still to the north of Lake Superior
and doesn't rotate into the region until Saturday. However, will try
to be somewhat consistent with the previous forecasts and with the
other offices so have lowered the probability of precipitation a bit so as to not totally
remove it. Overnight, is much the same, although it does look as if
the models, losing the day time heating, lose the ability to produce
precipitation. However, it looks like there is a decent shortwave
trough that is moving into east upper between 06z and 12z, so will go
with chance of showers.

(8/1) looks like there is a pocket of dry air in the
700-500 mb layer that looks like it would push the chances of east
of the region by the afternoon. However, with the northwest flow, if
we can warm enough, can't count out a shower, but it looks rather
quiet at the beginning of the weekend. Overnight, a better, strong
500 mb shortwave looks to be moving into the upper Great Lakes with
an associated surface trough. The European model (ecmwf) has our forecast area surround,
while the GFS brings the showers and thunderstorms through the
region from the southwest. European model (ecmwf) has this same system, but just
gets it to US-10 by 12z so will go with showers and slight chance of
thunder, since we will be on the cold side of the front and the surface


Long term...(sunday through wednesday)
issued at 411 am EDT Thursday Jul 30 2015

Extended (sunday through wednesday)...after our brief foray into
Summer, it looks like the 500 mb low that was locked in over
Hudson/James Bay for the last two years, has grown and reestablished
itself, again. The mex and ecm numbers are trending below normal and
looking at the cips analogs as well, we are going to be cooler than
normal with rain showers and possibly thunderstorms periodically
over the last 4 days of the forecast period. The temperature trend
is probably right, but as has been the problem this Summer, the
models haven't exactly done well with precipitation over our
forecast area. So wouldn't be surprised if the rain is light or none


Aviation...(for the 06z tafs through 06z Thursday night)
issued at 116 am EDT Thursday Jul 30 2015

VFR conditions overnight through Thursday morning...low level wind
shear tonight with gusty winds developing shortly after daybreak.


issued at 411 am EDT Thursday Jul 30 2015

Today/tonight...small craft advisories will need to be extended and
expanded across all nearshore zones into this evening...and possibly
along Northern Lake Huron through midnight. Building waves likely
to lead to a high swim risk on Lake Michigan beaches today.

Outlook...additional hazards not anticipated through Friday night.


Apx watches/warnings/advisories...
LH...Small Craft Advisory until 8 PM EDT this evening for lhz345-346-

Small Craft Advisory until midnight EDT tonight for lhz347-348.

Lm...Small Craft Advisory until 8 PM EDT this evening for lmz323-341-

Ls...Small Craft Advisory until 8 PM EDT this evening for lsz321-322.



Near term...jpb
short term...jsl
long term...jsl

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