fxus63 kdtx 190000
area forecast discussion
national weather service detroit/pontiac mi
800 pm edt fri sep 18 2020
daytime cumulus has dissipated this evening with mostly clear skies
taking over through tonight. the only exception will be some passing
cirrus coming in from the northwest. high pressure drifting east
through the central great lakes will bring light northeasterly winds
which will begin to back out of the southeast throughout the day
tomorrow as the high pressure drifts east of the state. daytime
cumulus will become harder to come by tomorrow with drier air in
place and lake moisture becoming less influential, but it remains
possible that some few-sct cumulus could develop again around 5kft.
winds will remain weak at around 5 knots.
.dtw threshold probabilities...
issued at 354 pm edt fri sep 18 2020
center of surface high pressure is centered over the portions of
lake michigan and northern lower michigan this afternoon. the
surface high has broad support from upper level confluent flow and
deep 950-550mb anticyclonic flow trajectories. main discussion point
for tonight will be on frost potential. ideal radiative cooling
conditions will develop tonight as surface decoupling occurs and
winds trend variable this evening. with surface dewpoints currently
running in the low to mid 30s and moist/green up conditions lows
tonight should remain buoyed in the lower to middle 30s across the
area. a few isolated interior locations across northern saginaw
valley may drop into the upper 20s. issued a frost advisory for the
entire cwa from midnight tonight through 9 am saturday
the main narrative throughout this upcoming weekend will be ideal,
dry, early autumn weather for southeast michigan. previous
discussion referenced low pwats throughout the entire weekend.
surface dewpoints will run in the 30s and 40s. temperatures this
weekend will be some 5 to 10 degrees below normal.
dry conditions are expected to persist through the early to middle
of next week. there is model signal the longwave will become
increasingly more amplified next week. the central great lakes
appear to be in a favorable position to experience a zonal flow
inflection point within the longwave. this is important as it
suggests a continued dry southwesterly trajectory. expecting some
movement on high temperatures for next week as current automated
values appear to be washed out. suspect high temperatures will be
warmer on a few days next week compared to what is currently being
onshore flow will persist through this afternoon as winds begin to
diminish through the early evening with conditions falling below
small craft criteria. high pressure will continue to build in from
the west and will move directly over the central great lakes and
bring more favorable boating conditions over the weekend with light
and variable winds and low wave action.
mi...frost advisory from midnight tonight to 9 am edt saturday for
lake st clair...none.
michigan waters of lake erie...none.
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