Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
FXUS63 KDTX 191044
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
544 AM EST Sun Feb 19 2017
Light northwest flow emerges early this morning in advance of
building high pressure. Exceedingly dry 00z sounding will undergo
little modification through the day supporting clear skies aside
from any passing cirrus. Decoupling tonight as high pressure settles
immediately to the north and east will support variable to
occasionally light east flow into Monday morning.
//DTW THRESHOLD PROBABILITIES...
Issued at 302 AM EST Sun Feb 19 2017
A 160 knot upper jet nosing into central California will lead to
downstream amplification of the long wave height field over the next
couple of days. This force the upper low over the desert SW to open
up as it lifts into the cntl/srn rockies today, while mid level
ridge amplification occurs across the upper Midwest. The mid level
ridge axis will then traverse Lower Mi on Monday. The influence of
this ridge will maintain dry conditions across the forecast area
today through the day Monday. There will however be some mid and
high level clouds from time to time today associated with subtle
forcing along a sharp mid/upper level frontal boundary extending
from Lake Superior to srn Lake Huron.
The passage of a weak frontal boundary last night has suppressed the
low level warm pool farther south, leaving a low level thermal
gradient across Se Mi. The post frontal cold air advection was not
very aggressive. In fact, 925mb temps will remain in the single
digits through the day. Considering the degree of over achievement
on high temps yesterday, daytime heating should support high temps
into the lower 60s for metro Detroit and point south, with temps
graduated toward the upper 40s across the nrn thumb. There will be a
chance record highs may again be broken today. The records for today
are: DTW 64 (1884); FNT 59 (1994); MBS 57 (1930). The building upper
level ridge will result in strengthening sfc high pressure across
nrn Ontario today. This high will expand into the eastern Great
Lakes Monday. It will force a secondary cold front to push into the
region from the northeast. This front, modified by the cold waters
of Lake Huron, is expected to slide across the thumb region this
evening, then push across the region of the forecast area during the
night. The result will be a rapid drop in temps into the 30s.
Easterly flow off the lakes will persist through Monday, holding
daytime highs in the 40s and low 50s (which is still a good 15 deg
above late Feb norms).
The mid level trough over the Rockies is forecast to eject to the
northeast, tracking across the Great Lakes Monday Night and Tuesday.
This wave is forecast to dampen but will lead to the advection of a
narrow plume of deep layer moisture. This couple with the brief
forced mid level ascent will provide a good chance for rain Monday
night/early Tuesday. Very warm low level air will then advect right
back into the region in the wake of the Tues system, supporting very
mild conditions through the end of the work week. The medium range
model suite continue to show fairly good agreement in the
development of a strong low pressure system over the midwest on
Friday. This system will have the potential to bring rain, maybe
even some thunderstorms, and gusty winds Fri/Fri night. Much colder
air is then forecast to funnel in behind this system, bringing temps
back toward more seasonal levels next weekend.
Moderate northwest flow will diminish late, becoming light northerly
overnight. Wind will then gradually veer to southeasterly through
the day Monday gusting as high as 25 kts Monday night into Tuesday
in advance of a cold front. Wind rapidly diminishes Tuesday
afternoon as the pressure gradient weakens.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
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