518  
FXUS63 KDTX 290706  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
306 AM EDT WED JUN 29 2016  
   
DISCUSSION
 
 
HIGH PRESSURE WILL SETTLE INTO THE WESTERN AND CENTRAL GREAT LAKES  
TODAY BEFORE SHIFTING SOUTH INTO THE OHIO VALLY EARLY ON THURSDAY.  
LARGE-SCALE SUBSIDENCE ASSOCIATED WITH THE HIGH AND SHORTWAVE  
RIDGING ALOFT WILL BRING MOSTLY CLEAR SKIES TODAY AND TONIGHT. AFTER  
A CHILLY START TO THE MORNING, DRY AIRMASS AND SUNSHINE WILL ALLOW  
MAX TEMPS TO RISE BACK INTO THE 70S AND EVEN NEAR 80 FROM DETROIT  
SOUTHWARD. (5 TO 10 DEGREES WARMER THAN YESTERDAY). EXCELLENT  
RADIATIONAL COOLING WILL LEAD TO A CHILLY NIGHT ONCE AGAIN, WITH LOW  
TEMPERATURES FALLING INTO THE MID/UPPER 40S TO LOW 50S MOST AREAS,  
AND UPPER 50S IN THE DETROIT HEAT ISLAND.  
 
UPPER SHORTWAVE OVER MANITOBA/SASKATCHEWAN WILL PIVOT DOWN AROUND  
LOW PRESSURE NEAR HUDSON BAY, SWINGING ACROSS MICHIGAN LATE THURSDAY  
THROUGH EARLY FRIDAY. THIS WILL PUSH A SURFACE TROUGH AND COLD FRONT  
ACROSS THE STATE THURSDAY NIGHT, PROVIDING THE ONLY CHANCE FOR  
RAINFALL IN THE 7-DAY FORECAST. ALTHOUGH COOLER AIR ALOFT LOOKS TO  
START ARRIVING THURSDAY AFTERNOON, GFS/NAM MODEL FORECAST SOUNDINGS  
DO NOT SHOW IT WILL BE SUFFICIENT ENOUGH TO ERODE THE CAP UNTIL 00Z  
OR LATER. MOISTURE ALSO LOOKS TO REMAIN FAIRLY MEAGER THROUGH ABOUT  
THIS TIME AS WELL, AND HAVE KEPT THE FORECAST DRY THROUGH 00Z/8PM  
THURSDAY. SUNSHINE WILL BE PREVALENT FOR THE FIRST HALF OF THE DAY  
BEFORE CLOUDS START TO WORK IN FROM WEST TO EAST. THIS, BETTER  
MIXING, AND H850 TEMPS RISING TO 12-14C WILL RESULT IN MAX TEMPS IN  
THE UPPER 70S TO LOW 80S.  
 
A SOLID SHOT OF QUICK BUT DEEP LAYER FORCING LOOKS TO ACCOMPANY THE  
FRONT OVERNIGHT AS PVA AND RIGHT ENTRANCE REGION HELP SURFACE TROUGH  
AND COLD FRONT. MOISTURE (THETA-E AXIS) LOOKS TO POOL JUST AHEAD OF  
THE FRONTAL BOUNDARY, WITH PW VALUES RISING TO BETWEEN 1.0 AND 1.5  
INCHES. INSTABILITY LOOKS LIMITED HOWEVER, WHICH SHOULD TEMPER THE  
RESPONSE FROM LIFT AND MOISTURE. THIS DOES NOT LOOK LIKE AN OVERALL  
GOOD CHANCE FOR MEANINGFUL RAIN AS DURATION OF MOISTURE/LIFT LOOK  
CONFINED TO AT MOST A 6 HOUR WINDOW, LIKELY SHORTER PER MODEL CROSS-  
SECTIONS, AND WE MUST FIRST OVERCOME THE DRY AIRMASS ALREADY IN  
PLACE. MODEL QPF OF MORE THAN 0.25 INCHES LOOKS OVERDONE. FRONTAL  
PASSAGE LOOKS TO OCCUR ACROSS SOUTHEAST MICHIGAN DURING THE LATE  
OVERNIGHT HOURS THROUGH MID-MORNING ON FRIDAY. CHANCES FOR SHOWERS  
AND PERHAPS A THUNDERSTORM WILL THEREFORE LINGER INTO THE EARLY PART  
OF FRIDAY FOR THE EASTERN PORTION OF THE FORECAST AREA BEFORE DRIER  
AIR AND SUBSIDENCE BEHIND THE MID-LEVEL TROUGH WORK INTO THE AREA.  
 
SURFACE HIGH PRESSURE WILL SLOWLY REBUILD INTO THE AREA FOR THE  
HOLIDAY WEEKEND, YIELDING HIGHER CONFIDENCE FOR DRY WEATHER AND  
ALLOWING MAX TEMPERATURES TO WARM BACK INTO THE LOW/MID 80S BY THE  
FOURTH OF JULY. SURFACE HIGH CENTER WILL SHIFT EAST FOR TUESDAY AND  
WEDNESDAY AS UPPER HEIGHTS BUILD AS AN EXTENSION OF STRONG UPPER  
RIDGING OVER THE SOUTHEASTERN U.S.. LATEST GUIDANCE SUGGESTS  
TEMPERATURES WARMING BACK UP INTO THE UPPER 80S TO NEAR 90 BY  
WEDNESDAY.  
 

 
   
MARINE
 
 
HIGH PRESSURE WILL SETTLE OVER THE GREAT LAKES TODAY THROUGH TONIGHT  
AND BRING FAVORABLE MARINE CONDITIONS TO LAKE HURON THROUGH WESTERN  
LAKE ERIE. THE NEXT COLD FRONT IS THEN EXPECTED TO MOVE INTO THE  
REGION THURSDAY NIGHT AND BRING A PATTERN OF SHOWERS AND POSSIBLY A  
THUNDERSTORM. NORTHWEST WINDS WILL RAMP UP AGAIN TO MODERATE SPEED  
THROUGH FRIDAY BUT ARE NOT YET PROJECTED TO REACH SMALL CRAFT  
ADVISORY CRITERIA. ANOTHER ROUND OF HIGH PRESSURE WILL BE IN PLACE  
OVER MARINE AREAS BY SATURDAY.  
 

 
   
PREV DISCUSSION
 
 
ISSUED AT 1205 AM EDT WED JUN 29 2016  
 
AVIATION...  
 
MAINLY CLEAR SKIES AND LIGHT WINDS WILL HOLD SERVE OVER THE  
SOUTHEAST TERMINALS THROUGH TODAY.  
 
FOR DTW...NORTH/NORTHWEST WINDS SHOULD STAY LIGHT ENOUGH TO ALLOW  
FOR SOUTHERLY FLOW OPERATIONS.  
 
//DTW THRESHOLD PROBABILITIES...  
 
* NONE  
 

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

 
 

 
 
DISCUSSION...HLO  
MARINE.......BT  
AVIATION.....MANN  
 
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE  
AT WWW.WEATHER.GOV/DETROIT.  
 
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