Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Detroit/Pontiac Michigan
324 PM EDT Tuesday Jun 2 2015
large surface high pressure over eastern Canada nosing back into the
Great Lakes tonight will continue a dry and cool northeasterly flow
into the area. Minor warm air advection aloft will occurr as middle
level heights rise slightly. This will help moderate lows
tonight a few degrees but still remain below average for this time
of year. With skies mostly clear...light to calm winds and low
dewpoints...most will have lows in the 40s except for pockets of
upper 30s possible in the interior of The Thumb and western Midland
Long term...Wednesday through next Tuesday
A fairly quiet start to the long term period as strong surface high
pressure and upper level ridging persists through Thursday. This
high will result in dry conditions and calm winds across Southeast
Michigan on Wednesday with limited moisture in the atmosphere
keeping skies mostly clear. As diurnal heating continues into the
afternoon... a scattered cumulus deck may develop across parts of the
County Warning Area. Mostly clear skies will allow temperatures to easily rise into
the middle 70s by late Wednesday afternoon. Sunset and the lack of
continued diurnal heating will result in any cloud development to
dissipate. Under mostly clear skies...low temperatures will drop
into the low to middle 50s Wednesday night.
High pressure will slowly drift eastward by Thursday
morning...keeping the morning hours dry. However...increasing clouds
will be possible as low pressure over the Tennessee Valley slides
northward. This low will filter in a layer of deep middle level
moisture into Southeast Michigan. In addition...current model runs
are trying to show a small area of increased instability across
extreme Southeast Michigan. The result in the combination of these
will be a chance of rain showers /and possible thunderstorm/ late
Thursday afternoon and early evening...mainly south of the M-59
corridor. Uncertainty definitely still remains in how intense these
showers will be...if they even develop at all. Therefore...did not
feel comfortable putting anything more than a slight chance in the
forecast for Thursday afternoon and evening.
Showers come to an end by late evening as weak high pressure returns
for Thursday night. However...regardless of dry conditions...clouds
will persist overnight as the next low pressure system approaches
from the west. Low temperatures on Thursday night will remain on the
warmer side /lows upper 50s to low 60s/ as a result of the clouds
inhibiting any nocturnal cooling.
Shortwave trough still expected to quickly transit the lower Great
Lakes or just south of there on Friday. Lowered probability of precipitation a bit Friday as
models have trended the forcing with this wave further
South/West...though relatively moist airmass still warrants low
chance probability of precipitation. Northwesterly upper flow in the wake of this wave will
promote surface high pressure expansion over western Great Lakes
leading to a dry and cooler Saturday. 12z GFS/Euro advertising a
more robust wave Sunday or Sunday night...mid-range chance probability of precipitation in
High pressure will keep winds light and conditions dry across the
Great Lakes through Thursday. A slight chance of an isolated shower
or thunderstorm will be possible /mainly across Lake St. Clair and
Lake Erie/ late Thursday afternoon as diurnal heating causes some
instability in the atmosphere. The next low pressure returns on
Friday bringing a better chance for unsettled weather to the Great
Aviation...issued 1259 PM EDT Tuesday Jun 2 2015
Few-scattered diurnal cumulus around 5k feet this afternoon as high pressure
ridging continues to nose in from Canada. This will continue a
light easterly flow through the taf period.
//Dtw threshold probabilities...
Lake St Clair...none.
Michigan waters of Lake Erie...none.
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