893  
FXUS63 KDTX 041153  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
653 AM EST WED MAR 4 2015  
 
   
AVIATION
 
 
MVFR CIGS WILL BE SLOW TO ERODE TODAY...EXPECT PERHAPS MBS/FNT WHERE  
COLD FRONT WILL PASS THROUGH AND BRING DRIER NORTHWEST FLOW EARLIER  
IN THE DAY. FURTHER SOUTH...CIGS AROUND 2500 FEET WILL GRADUALLY  
LIFT TO 3500 FEET OR SO AND TREND TOWARDS BKN AS THIS FRONT CLIPS  
THE AREA. VFR CONDITIONS WILL THEN DEVELOP TONIGHT AS A SECONDARY  
SURGE OF DRIER...COLDER AIR PUSHES INTO THE AREA AS HIGH PRESSURE  
BUILDS IN FROM THE WEST.  
 
FOR DTW...MVFR CEILING WILL LINGER IN ADVANCE OF THE COLD FRONT  
BEFORE IMPROVING SLIGHTLY INTO VFR POST FRONT DURING THE MORNING  
 
//DTW THRESHOLD PROBABILITIES...  
 
* HIGH FOR CEILINGS BELOW 5000 FT THROUGH 20Z OR SO.  
 

 
   
PREV DISCUSSION
 
ISSUED 347 AM EST WED MAR 4 2015  
 
SHORT TERM...TODAY AND TONIGHT  
 
RATHER QUIET WEATHER EXPECTED OVER THE NEXT 24 HOURS. A COLD FRONT  
WILL SETTLE THROUGH THE AREA TODAY AND BRING OCCASIONAL FLURRIES TO  
PARTS OF THE AREA. THIS ACTIVITY WILL LIKELY BE LIMITED TO THE  
NORTHERN SECTIONS OF THE FORECAST AREA AS MINOR UPPER LEVEL SUPPORT  
WITH THIS FRONT SHIFTS EAST/SOUTHEAST INTO SOUTHERN ONTARIO WITH  
TIME LATE IN THE DAY. OTHERWISE...SKIES WILL GENERALLY BE MOSTLY  
CLOUDY AS COLD...CYCLONIC FLOW MAINTAIN UNSETTLED CONDITIONS OVER  
THE AREA...WITH CLOUD COVER FURTHER ENHANCED BY MOISTURE STREAMING  
FROM LAKE MICHIGAN AS THE AIRMASS BECOMES INCREASINGLY COLD DURING  
THE DAY AND LEADS TO SOME LAKE EFFECT/ENHANCED CLOUDINESS.  
 
HIGHS WILL RANGE FROM NEAR 20 OVER THE FAR NORTHERN THUMB/SAGINAW  
VALLEY TO THE MID/UPPER 20S SOUTH THROUGH THE I-69 CORRIDOR ON TO  
THE OHIO AND MICHIGAN STATE LINE. THESE HIGHS WILL MOST LIKELY COME  
IN THE EARLY TO MID AFTERNOON AS INCREASING COLD AIR ADVECTION  
DURING THE LAST HALF OF THE DAY CAP THE HIGHS AND LEAD TO SLOWLY  
FALLING TEMPERATURES FROM LATE AFTERNOON INTO THE EARLY EVENING.  
 
TEMPERATURES WILL CONTINUE TO DROP INTO TONIGHT AS THE NEXT PIECE OF  
ARCTIC AIR DEEPENS OVER THE AREA. AS SURFACE RIDGING ASSOCIATED WITH  
THIS AIRMASS SHIFTS INTO THE AREA...SOME GRADUAL CLEARING OF SKIES  
CAN BE EXPECTED...ESPECIALLY OVER NORTHERN SECTIONS OF THE REGION.  
THIS WILL ALLOW TEMPERATURES TO DROP TO ZERO OR SLIGHTLY BELOW IN  
MANY LOCATIONS ALONG AND NORTH OF I-69 WITH SINGLE DIGITS ABOVE ZERO  
THE RULE FURTHER TO THE SOUTH. THE FRESH SEVERAL INCHES OF SNOW WILL  
ALSO ASSIST IN RADIATIVE COOLING AND PROMOTE THESE COLDER MINIMUM  
TEMPERATURES. WILL MAINTAIN THE FORECAST M-59 SOUTH...BUT SHAVE A  
FEW DEGREES OFF OF LOWS FURTHER NORTH GIVEN THIS EXPECTATION. THIS  
WILL BRING WIND CHILLS DOWN TO 10 BELOW OR LESS IN SPOTS...BUT NOT  
QUITE TO THE ADVISORY CRITERION OF 15 BELOW...AT LEAST NOT IN A  
WIDESPREAD AND PERSISTENT MANNER.  
 
LONG TERM...THURSDAY THROUGH TUESDAY  
 
SOUTHEASTERN MICHIGAN WILL REMAIN UNDER THE GRIPS OF THE LARGE  
WAVLENGTH UPPER LEVEL TROUGH THROUGH THE UPCOMING WEEKEND...POSSIBLY  
BREAKING DOWN SOMETIME NEXT WEEK. THIS WILL LEAD TO A CONTINUATION  
OF BELOW NORMAL TEMPERATURES THURSDAY AND FRIDAY BEFORE MODERATING  
THIS WEEKEND. THE FIRST TWO ITEMS TO NOTE ARE THE FORECASTED LOW  
TEMPERATURES FRIDAY MORNING AROUND ZERO...AND THE POTENTIAL FOR  
WINDCHILLS FRIDAY MORNING TO RANGE BETWEEN 8 AND 18 DEGREES BELOW  
ZERO. THE NEXT FORECAST ITEM OF NOTE IS THEN BRISK SOUTHWESTERLY  
FLOW SETTING UP OVER ALL OF SOUTHEASTERN MICHIGAN DUE TO RETURN FLOW  
KICKING IN ON THE COLD/NORTHERN PERIPHERY OF THE SURFACE  
ANTICYCLONE. DESPITE LOW MIXING HEIGHTS DUE TO HIGH STABILITY...THIS  
IS A CLASSIC SETUP FOR A SIGNIFICANT GRADIENT FLOW SETUP. WINDSPEEDS  
FRIDAY AFTERNOON ARE EXPECTED TO REACH THE 20 TO 30 MPH...HIGHER END  
OF THE RANGE ACROSS THE NORTHERN CWA. WARM ADVECTION CLOUDS ARE THEN  
FORECASTED TO RETURN FRIDAY NIGHT AHEAD OF THE CLIPPER SYSTEM THAT  
WILL DIVE ACROSS THE REGION ON SATURDAY. MODELS HAVE BEEN VERY  
PERSISTENT IN THE OVERALL SHARP MIDLEVEL TROUGH THAT WILL ACCOMPANY  
THE SHORTWAVE ENERGY WHICH INCREASES THE POTENTIAL FOR BOTH  
TEMPERATURES TO CLIMB ABOVE THE FREEZING MARK SATURDAY AND SOME  
INCREASED PRECIPATION CHANCES. THATS ABOUT IT FOR THE INCREASING  
CONFIDENCE AS TIMING...PLACEMENT...STRUCTURE DIFFERENCES CONTINUE TO  
EXIST IN REGARDS TO THE CLIPPER SYSTEM.  
 
MARINE...  
 
WESTERLY WINDS WILL INCREASE EARLY TODAY AS ANOTHER SURGE OF ARCTIC  
AIR ADVANCES INTO THE REGION. THE WINDS SHOULD BE STRONGEST ACROSS  
NORTHERN LAKE HURON AS SOME DEGREE OF LINGERING SURFACE TROUGH IS  
EXPECTED ACROSS THE SOUTHERN HALF OF THE LAKE INTO THIS AFTERNOON.  
WINDS WILL THEN DECREASE LATE WED INTO THURS AS HIGH PRESSURE BUILDS  
INTO THE REGION FROM THE WEST. MAIN ITEM TO NOTE WITH THIS MARINE  
PACKAGE IS STRONG SOUTHWESTERLY WINDS DEVELOPING OVER THE GREAT  
LAKES FRIDAY ON THE NORTHWEST PERIPHERY OF THE SURFACE HIGH. CURRENT  
INDICIATIONS ARE WINDSPEEDS MAY REACH THE 30 TO 40 KNOT RANGE DURING  
THE AFTERNOON HOURS.  
 

 
   
DTX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LAKE HURON...NONE.  
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  

 
 

 
 
AVIATION.....DG  
SHORT TERM...DG  
LONG TERM....CB  
MARINE.......CB  
 
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE  
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  
 
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