Area Forecast Discussion
Issued by NWS Marquette, MI
FXUS63 KMQT 271919
Area Forecast Discussion
National Weather Service Marquette MI
319 PM EDT FRI MAY 27 2016
.SHORT TERM...(Today and tonight)
Issued at 456 AM EDT FRI MAY 27 2016
Continued difficult forecast as convection will be driven by subtle
shortwave energy that will be modified by upstream convection.
Prediction of convection from these shortwaves is difficult even
within 12 hours, so confidence is limited. Generally followed a
blend of mesoscale models for pops through the short term.
Looking for 2-3 very subtle waves to move through this afternoon
through tonight. Sfc and upper ridging this afternoon will help
somewhat limit convection, as will limited instability less than 500
J/kg as shown by all models. Have scattered showers and
thunderstorms over the west and central to 00Z tonight. Highs today
in the 70s away from the Great Lakes shores will be dependent on
cloud cover and precip.
Have likely pops moving in tonight as another shortwave moves in and
sfc ridging gives way to troughing. Fog redevelopment is also
expected over land tonight.
.LONG TERM...(Saturday night through Friday)
Issued at 319 PM EDT FRI MAY 27 2016
Nam shows a trough in the wrn U.S. with a shortwave over the
Mississippi River valley 00z Sun with a ridge over the ern U.S. This
shortwave moves across the upper Great Lakes Sat night and Sun.
Confidence continues to be low for this forecast overall as it
depends heavily on amount of convection which influences the cloud
cover which influences the temperatures. Hard to time the shortwaves
out and how much convection will fire with them which in turn
influences how much cloud cover and the temperatures. For now, will
not make very many changes to the going forecast and will have some
chance pops to low likely pops into Sunday night and then will keep
Memorial Day dry for now. Is not out of the question that there
could be some lake breeze convection that forms on Memorial Day as
GFS and NAM both generate a little qpf, but thinking right now is
that this is overdone and will keep dry. Will not change
temperatures much from the going forecast.
In the extended, GFS and ECMWF show a 500 mb closed low and trough
over the northern plains and another over the desert SW 12z Tue. The
trough over the northern plains moves slowly east 12z Wed and moves
into the upper Great lakes 12z Thu and this remains over the area
into Fri. Still looks unsettled this forecast period with
temperatures near normal. Mon night and Fri look to be the driest
for this forecast for right now.
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 145 PM EDT FRI MAY 27 2016
Isolated showers and perhaps a TSRA is expected this aftn into
tonight. Best chance of TSRA will be at KSAW late this aftn. VFR
conditions into early evening will follow trends of last couple
nights by deteriorating to IFR/LIFR overnight in low clouds and
fog. Light easterly flow off fog covered Lk Superior will result
in VLIFR conditions around airport minimums at KCMX. Should see
very low clouds and fog diminish mid morning Saturday but lower
MVFR deck may persist along with chance for showers.
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 349 AM EDT FRI MAY 27 2016
A relatively weak pres gradient/hi stability will dominate the Upper
Great Lakes this forecast period, so expect winds at or below 20kts.
Since moist air will linger over the chilly lake waters, fog will
linger into at least Sun.
Dense Fog Advisory until 6 PM EDT /5 PM CDT/ Sunday for LSZ162-
Dense Fog Advisory until 4 PM EDT Saturday for LMZ248-250.