874  
FXUS63 KDTX 282015  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
315 PM EST SUN FEB 28 2021  
   
DISCUSSION
 
 
STEADILY MODERATING THERMAL PROFILE IN RESIDENCE LOCALLY LATE THIS  
AFTERNOON WITHIN EMERGING POST-WARM FRONTAL LOW LEVEL SOUTHERLY  
FLOW, AS SOUTHEAST MICHIGAN LIES JUST OUTSIDE THE PENDING HEIGHT  
FALLS ASSOCIATED WITH A SHORTWAVE SHEARING NORTHEAST ACROSS THE LAKE  
SUPERIOR. ATTENDANT COLD FRONT ON PACE TO SWEEP ACROSS THE AREA  
BETWEEN 23Z AND 02Z AS THE HEIGHT FALL GRADIENT MIGRATES EAST. THIS  
TIMING STILL AFFORDS A NARROW WINDOW YET FOR CONTINUED LOW LEVEL  
WARM ADVECTION, LEAVING MILD EVENING CONDITIONS AS TEMPS PUSH TO OR  
WELL INTO THE 50S MOST LOCATIONS OUTSIDE OF THE SAGINAW  
VALLEY. INBOUND FRONTAL CONVERGENCE AND ENSUING COLD AIR ADVECTION  
MAINTAINS A CHANCE FOR RAIN DEVELOPMENT BY LATE EVENING. THIS  
PROCESS ALSO ENGAGES A HEIGHTENED WIND FIELD JUST OFF THE SURFACE,  
SUPPORTING A PERIOD OF POST-FRONTAL WESTERLY GUSTS OF 30 TO 35 MPH.  
HIGH MAGNITUDE COLD AIR ADVECTION OVERNIGHT NETS A SOLID 15-20  
DEGREE DROP IN TEMPERATURES AT 850 MB BY MID MORNING MONDAY. LOWS  
DIPPING BELOW FREEZING.  
 
THE ONGOING HEIGHT FALLS AND ACCOMPANYING COLD AIR ADVECTION IS  
EFFECTIVELY REINFORCED THROUGHOUT MONDAY, RESPONDING TO THE INFUSION  
OF DCVA TIED TO A TRAILING, STRONGER PV ANOMALY OF NORTHERN CANADIAN  
ORIGIN. LIMITED DIURNAL TEMPERATURE RESPONSE NOTED ACCORDINGLY,  
MAGNITUDE OF THE ADVECTIVE PROCESS ENSURING HIGHS REMAIN IN THE  
LOWER TO MIDDLE 30S. SOME EASEMENT OF THE PROJECTED WIND FIELD NOTED  
IN RECENT MODEL TRENDS, SUGGESTING A MORE STANDARD DIURNAL RESPONSE  
IN TERMS OF GUST POTENTIAL. GUSTS 25 TO 30 MPH DURING THE  
AFTERNOON/EARLY EVENING HOURS. MOISTURE QUALITY REMAINS ON THE  
LEANER SIDE, BUT THE UNDERLYING FORCING HELD WITHIN A STEEP LAPSE  
RATES ENVIRONMENT WITHIN THE BACKGROUND OF COLD CYCLONIC FLOW WILL  
MAINTAIN THE POSSIBILITY FOR SOME SNOW SHOWERS.  
 
CONFLUENT MID LEVEL NORTHWEST FLOW ABOVE SURFACE HIGH PRESSURE  
YIELDS DEEP LAYER STABILITY TUESDAY. A GRADUAL MODERATING TREND  
UNDER A BUILDING UPPER HEIGHT FIELD WORKING WITH FULL INSOLATION.  
HIGHS ARRIVING RIGHT AT SEASONAL NORMS - MID TO UPPER 30S. LONG  
RANGE MODEL GUIDANCE STILL PROJECTING A RATHER BENIGN STRETCH OF  
WEATHER LASTING THROUGH THE END OF NEXT WEEK. OVERALL PATTERN WOULD  
LEND TO A SOLID WARMING TREND FOR WEDNESDAY, BUT HINTS OF RENEWED  
HEIGHT FALLS AS LONGWAVE TROUGHING EMERGES TO THE NORTHEAST SUGGESTS  
A THERMAL REGIME THAT RESIDES CLOSER TO AVERAGE LATE NEXT WEEK.  
 

 
   
MARINE
 
 
LOW PRESSURE TRACKS OVER EASTERN UPPER MICHIGAN THIS AFTERNOON WITH  
SOUTHEAST WINDS VEERING TO SOUTHWEST BY THIS EVENING AHEAD OF THE  
ASSOCIATED COLD FRONT. THE FRONT BRINGS A SURGE OF INSTABILITY AND  
STRONG COLD ADVECTION TO THE CENTRAL GREAT LAKES LATE THIS EVENING.  
A GALE WARNING REMAINS IN EFFECT FOR NORTHERN AND CENTRAL LAKE HURON  
TO ACCOUNT FOR TWO PERIODS OF EXPECTED GALES: TONIGHT, MAINLY FROM  
8PM TO 5AM; AND AGAIN MONDAY AFTERNOON. DURING BOTH PERIODS,  
NORTHWEST GUSTS OF 35 TO 40+ KT CAN BE EXPECTED FOR THE WARNED AREA,  
WHILE GUSTS OF 20 TO 30 KT ARE MORE LIKELY FOR SOUTHERN LAKE HURON,  
LAKE ST. CLAIR, AND WESTERN LAKE ERIE WHICH ARE FARTHER REMOVED FROM  
THE STRONG COLD ADVECTION.  
 
A BRIEF LULL IN WIND STRENGTH FOLLOWS FOR THE MONDAY MORNING PERIOD  
BEFORE A SECOND STRONG COLD FRONT SWEEPS THROUGH MONDAY AFTERNOON.  
WINDS IN ITS WAKE WILL INCREASE BACK TO GALE FORCE FOR  
NORTHERN/CENTRAL LAKE HURON AND THE GALE WARNING WILL CONTINUE UNTIL  
LATE MONDAY EVENING. WAVES ACROSS THE OPEN WATER BUILD TO 8 TO 11 FT  
WHILE WAVES ALONG THE NEARSHORE ZONES OF LAKE HURON BUILD UPWARDS OF  
5 FT - A SMALL CRAFT ADVISORY HAS BEEN ISSUED THROUGH MONDAY NIGHT.  
HIGH PRESSURE THEN SLIDES ACROSS THE SOUTHERN GREAT LAKES ON TUESDAY  
MORNING AND ALLOWS WINDS TO WEAKEN.  
 

 
   
PREV DISCUSSION
 
 
ISSUED AT 1222 PM EST SUN FEB 28 2021  
 
AVIATION...  
 
SATELLITE AND OBSERVATIONS SHOW IFR/LIFR STRATUS CONTINUING TO  
SLOWLY PUSH NORTH EARLY THIS AFTERNOON. ACCOMPANYING FOG/MIST WILL  
LIKELY PERSIST THROUGH THE AFTERNOON THOUGH SOME GRADUAL VSBY  
IMPROVEMENT IS EXPECTED MID/LATE AFTERNOON ALLOWING VSBYS TO REACH  
BACK INTO/NEAR MVFR TERRITORY. MOST OF THE REGION IS CURRENTLY  
SITTING AT OR NEAR THEIR LOWEST EXPECTED CEILING HEIGHTS, WITH THE  
EXCEPTION OF MBS WHO WILL LIKELY SEE FURTHER DECREASES IN CIGS  
WITHIN THE NEXT COUPLE HOURS. SOME MINOR LIFTING OF CEILINGS IS  
POSSIBLE LATE AFTERNOON UNDER MUTED DAYTIME HEATING BUT CIGS WILL  
STAY IN IFR TERRITORY. LOW PRESSURE MOVING ACROSS THE UPPER GREAT  
LAKES WILL SWING A COLD FRONT THROUGH SE MI THIS EVENING PROVIDING  
ANOTHER PERIOD OF LIGHT RAIN SHOWERS. GENERAL TIMEFRAME FOR PRECIP  
IS BETWEEN 22-01Z (MBS LIKELY A TOUCH EARLIER, 20-00Z). ACTIVITY  
WILL BRIEFLY LOWER CIGS TO LOW IFR AGAIN UNTIL THE COLD FRONT  
CROSSES THE REGION AROUND 01Z. WINDS WILL RAPIDLY SHIFT TO W BEHIND  
THE FRONT AND CONTINUE TO BACK TO NW TONIGHT. GUSTY CONDITIONS  
FOLLOW THE FRONT AS COLD AIR SURGES INTO THE REGION ALLOWING GUSTS  
UP TO AROUND 25KTS THROUGH THE FIRST HALF OF TONIGHT.  
 
FOR DTW... LOWEST CEILINGS ARE CURRENTLY OCCURING WITH SLIGHT GRADUAL  
LIFTING EXPECTED THIS AFTERNOON INTO MID TO UPPER IFR TERRITORY.  
COLD FRONT IS EXPECTED TO CROSS THE TERMINAL AROUND 01Z THIS EVENING  
SHIFTING WINDS TO WESTERLY AND INCREASING GUST POTENTIAL UP TO  
AROUND 25KTS. THESE POST-FRONTAL WINDS WILL BRING THE POTENTIAL FOR  
WEST FLOW OPERATIONS INTO EARLY TONIGHT. LIGHT RAIN SHOWERS ARE  
POSSIBLE AHEAD OF THIS FRONT BETWEEN 22-01Z CAUSING REDUCTIONS IN  
CIGS TO LOW IFR-NEAR LIFR.  
 
DTW THRESHOLD PROBABILITIES...  
 
* HIGH FOR CEILING 5000 FT OR LESS THROUGH THIS EVENING.  
 
* HIGH FOR RAIN AS PRECIPITATION TYPE DURING THIS EVENING.  
 
* LOW FOR CEILINGS AT OR BELOW 200 FEET AND VISIBILITY OF A 1/2 MILE  
OR LESS.  
 

 
   
DTX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR LHZ421-441>443.  
 
GALE WARNING UNTIL 10 PM EST MONDAY FOR LHZ361>363.  
 
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  

 
 

 
 
DISCUSSION...MR  
MARINE.......TF  
AVIATION.....KDK  
 
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AT WWW.WEATHER.GOV/DETROIT.  
 
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