999  
FXUS63 KDTX 220754  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
350 AM EDT WED OCT 22 2014  
   
SHORT TERM
 
TODAY AND TONIGHT  
 
SOUTHEAST MICHIGAN HOLDING FIRM THIS MORNING WITHIN THE EXISTING MID  
LEVEL CYCLONIC FLOW ATTENDANT TO THE OUTER PERIPHERY OF THE  
SPRAWLING CLOSED MID LEVEL CIRCULATION POSITIONED OVER THE MID  
ATLANTIC COASTLINE. RETENTION OF A MODESTELY DEEP NORTH-NORTHEAST  
GRADIENT UNDER THIS PATTERN SUSTAINING AT LEAST A WEAK COLD AIR  
ADVECTIVE COMPONENT...AND LIKELY PROVIDING SOME DEGREE OF MOISTURE  
FLUX CONTRIBUTION OFF LAKE HURON. THE NET RESULT EARLY THIS MORNING  
BEING THE SOLIDIFICATION AND RENEWED WESTWARD EXPANSION OF STRATUS  
ACCOMPANYING THIS COOLING/MOISTENING OF THE SUB-INVERSION LAYER.  
LATEST SOUNDING ANALYSIS AND LOW LEVEL RH FIELDS CONTINUE TO SUGGEST  
THE EXTENSIVE DRY LAYER EXISTING AT THE EDGE OF BUILDING HIGH  
PRESSURE JUST UPSTREAM WILL TAKE SOME TIME TO MAKE BETTER INROADS  
LOCALLY TODAY. THIS POINTS TO A MOSTLY CLOUDY FIRST HALF OF THE  
DAY...BEFORE INCREASING SUBSIDENCE AND DRY AIR ADVECTION AIDES IN A  
PROGRESSIVE CLEARING TREND DURING THE AFTERNOON. HIGHS TODAY IN THE  
LOWER AND MIDDLE 50S.  
 
HIGH PRESSURE DOMINATED CONDITIONS EXPECTED TONIGHT. A DIMINISHING  
GRADIENT FLOW...CLEAR SKY...AND DRY MID LEVEL ENVIRONMENT CONTINUE  
TO LEND CONFIDENCE TOWARD WITNESSING A STRONG RADIATIONAL COOLING  
RESPONSE OVERNIGHT. LOWS MAKING A RUN INTO THE UPPER 20S IN THE  
COLDEST LOCALES.  
 

 
   
LONG TERM
 
THURSDAY THROUGH TUESDAY  
 
THURSDAY WILL START WITH RIDGING AT THE SURFACE AND ALOFT OVER  
SOUTHEAST MICHIGAN. THIS SHOULD MAINTAIN QUIET AND DRY CONDITIONS  
OVER THE AREA. SUNSHINE AND WEAK THERMAL ADVECTION (H850 TEMPS UP TO  
8C) WILL HELP BOOST TEMPERATURES INTO THE MID 50S. MODELS THEN  
CONTINUE TO SHOW SOME MINOR DIFFERENCES WITH HOW THEY HANDLE ENERGY  
WITHIN THE UPPER TROUGH NOW SEEN ON WATER VAPOR STRETCHING FROM THE  
CANADIAN ROCKIES DOWN TOWARDS THE FOUR CORNERS. NAM IS A FAST  
OUTLIER WITH THE ENERGY INTO THE GREAT LAKES...WHILE THE EURO/GEM  
NOW SPLIT THE ENERGY...TAKING THE BIGGER PIECE DOWN INTO THE  
TENNESSEE VALLEY WHILE THE REST CROSSES MICHIGAN LATE THURSDAY NIGHT  
AND FRIDAY. THESE SOLUTIONS CONTINUE TO SHOW MOST OF THE MOISTURE AT  
THE MID AND UPPER LEVELS...AND SHOW LITTLE IN THE WAY OF A LOW-LEVEL  
FORCING MECHANISM. THIS CONTINUES TO SUPPORT A DRY FORECAST WITH  
JUST AN INCREASE IN CLOUDS...BUT WILL CONTINUE TO MONITOR MODEL  
SOLUTIONS AND WATER VAPOR IMAGERY IN CASE CHANGES ARE WARRANTED.  
 
MEDIUM-RANGE MODELS THEN CONTINUE TO SHOW STRONG CONTINUITY WITH A  
LARGER UPPER LOW OVER THE GULF OF ALASKA DIVING THROUGH ONTARIO  
FRIDAY NIGHT THROUGH SATURDAY NIGHT. INCREASED MIXING AHEAD OF A  
COLD FRONT ASSOCIATED WITH THIS FEATURE SHOULD BOOST TEMPERATURES  
CLOSER TO 60 ON SATURDAY...AS WE MIX INTO WARMER AIR ALOFT THAT  
SHOULD ARRIVE LATE FRIDAY. DRY COLD FRONT IS THEN PROGGED TO DROP  
THROUGH SATURDAY EVENING...BRINGING AN INCREASE IN WINDS AND  
DROPPING TEMPERATURES BACK DOWN INTO THE 50S FOR SUNDAY.  
 
GFS/EURO THEN IN STRONG AGREEMENT WITH UPPER RIDGING SLIDING OVER  
THE AREA SUNDAY INTO MONDAY...CONTINUING THE STRETCH OF DRY WEATHER.  
AN APPROACHING TROUGH SHOULD HOWEVER BOOST WIND SPEEDS ON  
MONDAY...THEN BRING A CHANCE FOR SHOWERS ON TUESDAY.  
 

 
   
MARINE
 
GUSTY WINDS AND LARGE WAVES OVER LAKE HURON WILL CONTINUE  
TO SUBSIDE THROUGH THE EARLY MORNING HOURS AS LOW PRESSURE MOVES  
TOWARDS THE EAST COAST AND A RIDGE OF HIGH PRESSURE BEGINS TO SETTLE  
INTO THE CENTRAL GREAT LAKES. THE HIGH WILL REMAIN OVERHEAD INTO  
THURSDAY...BRINGING FAIRLY CALM CONDITIONS AND DRY WEATHER. THE NEXT  
PERIOD OF INCREASED WINDS IS EXPECTED SATURDAY INTO SUNDAY AS A COLD  
FRONT DROPS THROUGH THE AREA. SMALL CRAFT ADVISORIES MAY BE NEEDED  
FOR PORTIONS OF LAKE HURON.  
 

 
   
AVIATION
 
ISSUED 1156 PM EDT TUE OCT 21 2014  
 
A DEEP LOW LEVEL INVERSION AND A MOIST NE FLOW OFF LAKE HURON WILL  
SUSTAIN THE STRATUS THROUGH THE MORNING. STRONG SUBSIDENCE ABOVE THE  
INVERSION SHOULD HOLD MVFR CEILINGS /2K TO 3K FT/. DRY AIR ACROSS  
THE NORTHERN GREAT LAKES WILL ATTEMPT TO NUDGE IN FROM THE NORTHWEST  
WED AFTERNOON AS HIGH PRESSURE TAKES HOLD ACROSS LOWER MI. THIS WILL  
LEAD TO A GRADUAL EROSION OF THE CLOUDS.  
 
FOR DTW...  
 
//DTW THRESHOLD THREATS...  
 
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT THIS MORNING. LOW  
CONFIDENCE WED AFTERNOON.  
 

 
   
DTX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
 
LAKE HURON...  
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT  
HURON INCLUDING OUTER SAGINAW BAY...UNTIL 8 AM WEDNESDAY.  
 
LAKE ST CLAIR...NONE.  
 
MI WATERS OF LAKE ERIE...NONE  
 

 
 

 
 
SHORT TERM...MR  
LONG TERM....HLO  
MARINE.......HLO  
AVIATION.....SC  
 
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE  
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab MI Page Main Text Page