Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 161742
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1242 PM EST Thu Feb 16 2017


.AVIATION...

Band of lower clouds stretched over and just west of terminals at
1700Z will slide eastward over the next few hours, while drier air
entrainment into the area will also cause these clouds to thin and
dissipate. Expect VFR conditions by 20Z. High pressure over the area
will then provide lighter winds and allow for only high clouds into
the evening. Broad troughing extending into the Northern Plains from
low pressure over Canada will lift an elevated warm front through
the area this evening and early tonight. An area of mid-level clouds
will pass across Lower Michigan tonight as this occurs, with little
impact to the terminals.

For DTW...Clouds near 3500 feet will move east while also thinning
over the next few hours. Expect VFR conditions to develop in the 19-
20Z window. Winds will trend lighter and turn more westerly through
the afternoon, then become light and variable in the evening.

//DTW THRESHOLD PROBABILITIES...

* Medium for ceilings below 5000 feet through 19Z today.

&&

.PREV DISCUSSION...
Issued at 305 AM EST Thu Feb 16 2017

DISCUSSION...

One last cold day before a big time warm up occurs, with temperatures
surging toward record values on Saturday.

Lowering inversion heights with low level anti-cyclonic flow
building in today, coupled with the daytime mixing expected to
dissipate low clouds, as breaks in the clouds noted over Lake
Michigan early this morning. As the low clouds scour out this
afternoon, mid clouds will be streaming in with good warm advection
pattern setting up. Upper wave over central Manitoba early this
morning to track through southern Lower Michigan this evening, but
the low levels expected to be too dry to support any snow.

The highly amplified central North American Ridge will then fold
over into the Great Lakes region, arriving Friday Night. The warm
advection will be very impressive, with 850 mb temps forecasted to
reach to near 12 C Saturday Morning, per 00z Euro. With plenty of
insolation expected and good low level southwest flow on Saturday
ahead of a cold front, skewed the forecast to the higher side, but
still not as high as the lower 60s offered up by the Euro Mos.
Around a third NCEP SREF temp plumes indicating highs around 60
degrees for Detroit, and expecting maxes in the 55 to 60 degree
range across the majority of southeast Michigan.

Friday looks to be a bigger challenge, as the temperature plume
spread is greater, as there is uncertainty with how quickly the
surface warm front lifts north. It will probably take most of the
day, and with the surface flow backed out of the southeast coming
off Lake St. Clair/Erie and limited mixing, temps will likely remain
in the 40s, but there is a couple SREF outliers and euro mos
indicating late day surge to 50+ degrees, so not out of the question.

Dry cold front passage late in the day Saturday or during the
evening, and the 00Z euro has trended stronger with the cold
advection filtering in as upper level trough deepens over New
England. Fairly tight baroclinic zone over the area, with 925 mb
temps of 5 C to 9 C south during Sunday, but mixing depths likely
coming up just short of that level. Even so, assuming mostly sunny
skies, still thinking lower 50s are likely.

Warm advection pattern returns on Monday, but backed surface winds
out of the southeast will likely hold maxes in the 50 to 55 degree
range, and Tuesday could actually end up being warmer if the next
cold front is a bit slower. However, with the upper level pattern
splitting off, a faster northern stream trough passage is favored at
this time, but in a weakening state as main upper level energy heads
into Ontario. Thus, just chance pops for Tuesday at this time.

MARINE...

Midlevel cold pool within thermal trough and associated steep low
level lapse rates will stay in place over the central Great Lakes
throughout the remainder of the morning hours. Northwest winds will
remain in the 15 to 25 knot range during this time. Northwest winds
will then decrease dramatically this weekend in response to a
surface ridge pushing directly into the area. Variable winds are
expected tonight with modest southeasterly winds developing for
Friday. All signs point to an extended run of relatively benign
marine conditions, less than 20 knots, right into next week. The one
exception will be a period of modest westerly flow developing over
both the southern Great Lakes and northern Great Lakes Saturday.
West winds of around 20 to 25 knots will be possible then.

CLIMATE...

Record highs for Saturday February 18th:

Detroit 62 degrees (1976)
Flint 56 degrees (2011)
Saginaw 53 degrees (1981)

Outside of 59 degrees at Saginaw for Feb 19th, daily highs reside in
the lower 60s Sunday Feb 19th through Tuesday Feb 21st, with the
majority of the daily records in that time frame from 1930.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....HLO
DISCUSSION...SF
MARINE.......CB
CLIMATE......DG
CLIMATE......DG


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.



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