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FXUS63 KDTX 202330

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
730 PM EDT Tue Mar 20 2018


Prevailing northeast flow will sustain dry low level conditions 
through the TAF period.  While a thickening canopy of high cloud 
will lift into the region tonight, this will ensure skies remain 
clear across the lowest 7-8k ft. Evidence of a narrow strip of 
stratus lifting from Saginaw Bay into MBS is waning now, so will 
lean toward simply a scattered coverage moving forward.  Gusty 
northeast winds will ease early tonight as diurnal support fades, 
but with the occasional gust near 20 knots still likely through the 

For DTW...Winds hold from the north-northeast /010-030 direction/ 
tonight, gradually easing in both magnitude and gust frequency. 
Gradual backing of winds to north and north-northwest throughout 
Wednesday. Skies to remain clear across the lowest 5000 ft through 


* None.


Issued at 309 PM EDT Tue Mar 20 2018 


Strong Canadian high pressure (1030+ MB) will remain anchored 
along/near Ontario/Quebec border over the next several days. 

12Z DTX indicated a very dry airmass in place over southeast 
Michigan today, as 850 MB dew pt depression checked in at 32 C, with
a PW value of 0.14 inches. 

Brisk northeast winds will continue through tonight (holding min 
temperatures in the low/mid 20s), shifting to the North-Northeast 
early tomorrow morning. Strengthening low-mid level circulation 
tracking through southern Ohio will send 850-700 MB Theta-E gradient 
over Lenawee/Monroe counties overnight. But with continued low level 
feed of dry air, still looking at the snow shield holding near the 
southern Michigan border. 12z Regional Gem would even argue for 
light accumulations south of I-94 as 700 MB specific humidity rises 
to 2.5 G/KG. Preference is more toward the slightly drier RAP 
solution, but low chance pops for light snow late tonight still 
seems warranted south of I-94, especially if that flow becomes a bit 
more easterly off Lake Erie. 

Upper level shortwave ridging to become established on Wednesday. 
With northerly flow off cold waters of Lake Huron, looks like good 
temp gradient setting up during the day, as 925 mb temps advertised 
to range from -8 C over northern tip of the Thumb to -2 C along the 
southern Michigan border, translating to highs in lower 30s to lower

Dry airmass and skies becoming clear Wednesday night will lead to a 
favorable radiating night, sending temps into the lower 20s. Could 
even see mins sneak into the teens in the normally colder locations 
if winds fully decouple. 

Thursday and beyond...

Confluent NW flow still forcing all meaningful precip south of the 
area while ensuring mostly sunny skies with dominant high pressure 
at the surface. The third week of spring will see temperatures 
creeping ever-closer to average values as ridging builds over the 
central CONUS for the remainder of the forecast period.


Large High pressure to the north and a low pressure system moving up 
the Ohio Valley will continue a prolonged period of moderate 
northeast wind which will continue this afternoon through Wednesday 
before gradually diminishing Wednesday night.  Occasional gusts to 
30 kts are likely through Wednesday. The long northeast fetch over 
open water will build high waves through the period and small craft 
advisories remain in effect through Wednesday for all marine areas 
except Lake St Clair which is through tonight. Advisories will 
continue into Wednesday night for outer Saginaw Bay and Lake Huron 
near shore. The wind will weaken and back north by Wednesday night 
as the low exits the mid Atlantic coast and as the Ontario high 
builds over the western Great Lakes. This will allow waves to 
gradually diminish below advisory levels all areas by Thursday and 
last through Friday.


MI...Lakeshore Flood Advisory until 10 AM EDT Wednesday for MIZ083.

Lake Huron...Small Craft Advisory until 2 AM EDT Thursday for LHZ421-441>443.

     Small Craft Advisory until 4 PM EDT Wednesday for LHZ422.

Lake St Clair...Small Craft Advisory until 8 AM EDT Wednesday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 8 AM EDT Wednesday for LEZ444.




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