Area Forecast Discussion
Issued by NWS Marquette, MI
FXUS63 KMQT 220806
Area Forecast Discussion
National Weather Service Marquette MI
406 AM EDT Sat Apr 22 2017
.SHORT TERM...(This evening through Saturday)
Issued at 353 PM EDT FRI APR 21 2017
WV imagery and RAP analysis indicated a split flow pattern with a
ridge over the nrn plains and a trough into Quebec resulting in
confluent nrly mid/upper level flow through the nrn Great Lakes. At
the surface, brisk nrly winds were diminishing into Upper Michigan
as high pressure over the eastern Dakotas builds toward the area.
Tonight, the high will move overhead tonight with clear
skies/light winds. With PWAT values aob 0.25 inch very favorable
radiational cooling conditions will allow temps to drop toward the
lower end of guidance, into the lower 20s over interior west.
Expect higher readings tonight in the mid 30s near the relatively
warmer Great Lakes.
Saturday, sunshine and mixing through 850 mb temps in the 3C to 5C
range will push inland max temps into the lower to mid 60s. Winds
will be light enough to allow lake breeze development over the
central and east.
.LONG TERM...(Sunday through Friday)
Issued at 406 AM EDT SAT APR 22 2017
Nam shows a closed 500 mb low near Paducah, KY 12z Sun with a trough
over the upper Great Lakes. This trough moves east with another
trough moving into the Pacific NW 12z Mon. This trough moves into
the Rockies Mon night. Nam shows some 850-500 mb q-vector
convergence and deeper moisture over the area 12z Sun that remains
into 12z Tue. Frontal zone gets hung up over the area and remains
through Mon night. Moisture still remains limited until Mon night,
so will keep low chance pops in. Overall, did not make too many
changes to the going forecast.
In the extended, GFS and ECMWF show a broad 500 mb trough across the
Rockies into the plains 12z Tue. This trough moves into the upper
Great Lakes 12z Wed with some colder air moving in behind this
trough for Wed into Thu. A 500 mb trough over the Rockies on Thu
will strengthen and move into the northern plains 12z Fri. This
trough remains into Sat. Still looks unsettled for this period with
temperatures being the warmest on Tue and then going below normal
for Wed through Sat.
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 320 AM EDT SAT APR 22 2017
Dry high pres will dominate thru this aftn, ensuring VFR conditions
prevail at KIWD/KCMX/KSAW. A cold front will drop s across the area
tonight, passing KCMX during the evening and KIWD/KSAW overnight.
Cigs may drop to IFR or even LIFR just beyond this fcst period.
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 325 PM EDT FRI APR 21 2017
Lingering stronger nnw winds up to 20-25 kts over the e portion of
the Lake will diminish this evening with the arrival of a surface hi
pres. Expect a wind shift to the wsw on Sat as the hi center sinks
to the se. As the pres gradient tightens ahead of an approaching
cold front, wind speeds up to 20-25 kts will be possible in the
afternoon/evening in the area between the Keweenaw and Isle Royale,
where the topography funnels this flow. In the wake of the frontal
passage, n winds up to 20-25 kts will occur late Sat night into Sun
before the gradient slackens on Sun as hi pres building into Ontario
extends a ridge into the Upper Lakes. E veering s winds will then
increase up to 25 to 30 kts on Mon into Tue as a lo pres moves from
the ncentral Plains across the Upper Lakes. Where the winds are
stronger over portions of the ncentral and e parts of the Lake, not
out of the question there could be a gale at least a part of this
time depending on the strength of the lo pres. Expect a wind shift
to the n up to 25-30 kts on Wed following the exiting lo pres/
attendant cold frontal passage.