Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 231941

Area Forecast Discussion
National Weather Service Gaylord MI
341 PM EDT Thu May 23 2019

.NEAR TERM...(Through Tonight)
Issued at 244 PM EDT Thu May 23 2019

High Impact Weather Potential...Minimal

Pattern Synopsis/Forecast...Low pressure northeast of Lake
Superior has continued to produce cloud cover over portions of the
state, after its attendant cold front moved off the Lake Huron
shore this morning. Wrap around moisture and a 500 mb shortwave
are helping to produce stratocu over NW Lower and E Upper Michigan
with rain showers breaking out over E Upper Michigan. This will
continue to into the early evening, before the diurnal heating
diminishes, and along with it, the chances for rain showers with
the instability tailing off. Overnight looks to remain dry, but
the ECMWF does have a small chance for rain to move into the
forecast area, prior to 12z/Fri.

Primary Forecast Concerns...Rain starting prior to 12z/Fri.
Despite the ECMWF showing that a warm advection wing of rain
showers moves into the region between 09z and 12z/Fri, think that
this is unlikely based on the GFS/SREF/NAM/ARW/NMM and the ECMWF
soundings looking rather dry. So have thrown out the ECMWF QPF
idea of the chance pops in the SW portion of the forecast area.
This will leave a dry forecast for the area tonight.


.SHORT TERM...(Friday through Sunday)
Issued at 244 PM EDT Thu May 23 2019

High Impact Weather Potential: Minimal through the short term.

Pattern Synopsis/Forecast: Large scale analysis this afternoon
reveals an anomalously strong upper level ridge/very warm air
anchored across the SE states with 500 MB heights in excess of 590
DM. Heights are a bit more suppressed/cool-ish temperatures linger
across the Great Lakes owing to short-wave energy and attendant
surface low pressure rolling through the northern Great Lakes
region. Upstream, anomalously deep persistent troughing is across
the western CONUS. SW flow up through the central CONUS continues
(and will continue) to produce active weather across the Plains.

Moving through the upcoming holiday weekend, strong upper ridge will
remain anchored across the SE states through the entire weekend.
With the departure of the Great Lakes short-wave, upper level
ridging and warmer/more moist air is still looking to build up
through the Midwest and into the Great Lakes beginning Friday. But
shower chances will also increase later Friday/Friday night and into
Saturday as another system lifts up into Canada and attending cold
front slips through the region.

Primary Forecast Concerns/Challenges: Increasing shower/thunderstorm
chances Friday into Friday night. Lingering chances into Saturday.

In the wake of today`s short-wave/surface low, will start the day
rain-free on Friday as a narrow surface ridge axis slides across the
region. Meanwhile, short-wave energy and surface low pressure in the
western CONUS today will advance up into the northern Plains and
upper Midwest on Friday and into Ontario Friday night. Ahead of this
system, increasing warm advection/theta-e push into the western
Great Lakes will probably lead to some W-E shower development across
the forecast area as we go through the afternoon, although overall
coverage does not appear that least through the
daytime hours. I`ve slowed PoP timing and coverage just a bit versus
my inherited forecast.

Best shower/thunderstorm chances come Friday night and into Saturday
morning as an increasing and deep SW flow/increasing low level jet
drives low-mid level theta-e and instability axis up into lower
Michigan. This setup has the potential to bring some heavier
rainfall into parts of the Midwest into the Great Lakes although the
better threat is expected to be well off to our SW. Severe weather
threat for northern Michigan is low owing to time of day/low level
stability, although strong mid level winds and resulting 0-6 KM bulk
shear values in excess of 40 knots could lead to some organized
updrafts and hail potential. Will see how that goes.

For Saturday, cold front will slowly slip down through northern
Michigan with cooler air once again bleeding into the northern lakes
region. Saturday certainly appears a bit on the cloudier side as the
overnight precip axis only slowly departs to the S/E. In addition,
owing to cooler air aloft, hi-res guidance suggest there may be some
daytime heating driven showers (thunder maybe?) across the U.P. and
just down into the tip of the mitt during the afternoon into the
evening hours. I`ve lowered forecast max temperatures a degree or
two with the expected cloud cover and lingering precip.

High pressure builds back into the region for Sunday and I think we
will see at least a fair amount of sunshine along with temperatures
somewhat resembling readings close to normal.


.LONG TERM...(Sunday night through Thursday)
Issued at 244 PM EDT Thu May 23 2019

High Impact Weather Potential: Minimal.

Northern Michigan will remain on the northern periphery of strong
ridging anchored over the SE CONUS through the first half of the
week, with more or less flattened zonal flow through the Great Lakes
and temperatures near seasonal normals. Low pressure ejecting out of
the plains may bring another round of showers/thunderstorms during
the late Monday into Tuesday timeframe. Then, longer range guidance
suggests a bit of a pattern shift may be looming during the middle
to latter half of the week as a closed low and core of cold air
drops down through central Canada and into the Great Lakes. More
shower potential while temperatures get knocked back to below normal
readings once again.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 215 PM EDT Thu May 23 2019

The stratocu is making its way across Lake Michigan, which will
help to cover the region in clouds for the night. So far, the rain
showers have been contained to E Upper this afternoon, and will
expect that until this evening. Some of the showers may make it
south to the region, but make it a bit south into N Lower by this
evening. However, as we lose the heating after sunset, the cloud
cover will remain, but the rain showers should diminish. CIGS
overnight look to remain in the IFR to MVFR categories as the
moisture moves through the region.

The next system will move into the region tomorrow morning, with
mainly high clouds.


Issued at 244 PM EDT Thu May 23 2019

Will probably have to make some adjustments for the evening, but
for the most part, the winds have been mixing well enough over the
water to continue the small craft advisory. The tight gradient is
expected to remain so into the evening, before high pressure
begins to move into the region, and slacken the gradient, allowing
the winds to diminish. As the high moves by to the north, the
winds will continue to veer through the night and into Friday so
that by 00z/Sat, the winds will be out of the SE. The next front
moves through the region and will bring rains showers and
thunderstorms Friday night into Saturday. The winds continue to
veer to the SW by the afternoon, but the gusts should remain below
small craft criteria.


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 LMZ323-342-
LS...SMALL CRAFT ADVISORY until 8 PM EDT this evening for LSZ321-322.


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