559  
FXUS63 KDTX 062023  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
323 PM EST TUE JAN 6 2026  
   
KEY MESSAGES  
 
- A DENSE FOG ADVISORY IS IN EFFECT THROUGH 9PM THIS EVENING.  
 
- A CONTINUED WARMING TREND BRINGS HIGH TEMPS INTO THE 40S THROUGH  
MID-WEEK WITH 50S POSSIBLE THURSDAY AND FRIDAY.  
 
- THE NEXT ROUND OF WIDESPREAD RAIN IS EXPECTED LATE THURSDAY INTO  
THURSDAY NIGHT.  
 
- DYNAMIC LOW PRESSURE SYSTEM IS FORECASTED TO LIFT THROUGH THE  
REGION THIS WEEKEND. UNCERTAINTY EXISTS IN HEAVIEST PRECIPITATION  
AXIS.  
 
 
   
DISCUSSION  
 
COLD GROUND, SATURATED LOWER TROPOSPHERE, AND DEWPOINTS IN THE  
MIDDLE 30S HAS RESULTED IN WIDESPREAD DENSE FOG ACROSS MOST OF THE  
SOUTHERN FORECAST AREA. GIVEN THE BREADTH OF THE OBSERVATIONS AND  
THE LOW-MID LOW CIRCULATION IS NOT SET TO REACH THE EASTERN CWA  
BORDER TO AROUND 00Z, PREFERENCE WAS TO HAVE A DENSE FOG ADVISORY, I  
69 CORRIDOR SOUTHWARD, THROUGH THE EVENING COMMUTE. NWP SUPPORTS  
THAT DEEPER FRONTOGENESIS RESPONSIBLE FOR WIDESPREAD PRECIPITATION  
WILL WANE RAPIDLY AFTER 00Z AS THE CENTER OF MIDLEVEL LOW PRESSURE  
CIRCULATION PASSES OVERHEAD OF THE I 69 CORRIDOR. THERE WILL BE SOME  
TRAILING ABSOLUTE VORTICITY MAXIMA MERIDIONALLY FROM LAKE SUPERIOR  
VICINITY DOWN TO ILLINOIS THAT WILL NEED TO ADVECT THROUGH THE STATE  
THIS EVENING. DIFFERENTIAL CYCLONIC VORTICITY ADVECTION AND A  
PERSISTENCE OF SOME CONVERGENCE IS SHOWN TO RESULT IN SOME LAST  
VESTIGES OF DEEPER/MIDLEVEL DEFORMATION LATE TONIGHT. A LOW POP  
EXISTS LATE TONIGHT FOR SOME POTENTIAL OF DRIZZLE/FREEZING DRIZZLE  
OR SNOW SHOWER. NO IMPACTS ANTICIPATED FROM PRECIPITATION.  
 
BROAD SPLIT STREAM RIDGING WILL BUILD OVER THE CENTRAL GREAT LAKES  
WEDNESDAY THROUGH THE FIRST HALF OF THURSDAY. FORECAST SOUNDINGS  
SHOW ACTIVE SUBSIDENCE OCCURRING AROUND 9.0 KFT AGL EARLY IN THE  
DAY, WITH THE BASE OF THE SUBSIDENCE LOWERING TO POSSIBLY 2.5 KFT  
AGL BY EARLY EVENING. THE AGGRESSIVE DRYING OFFERS AN OPTIMISM OF  
CLEARING, BUT GUIDANCE SUGGESTS IT WILL BE VERY LATE (AFTER 20Z).  
HIGHS IN THE UPPER 30S.  
 
STRONG POTENTIAL VORTICITY ANOMALY OFF OF THE BAJA CALIFORNIA WITH  
ARRIVAL OF DEEP TROUGHING IN PACIFIC NORTHWEST WEDNESDAY AND  
THURSDAY WILL RESULT IN DOWNSTREAM RIDGE AMPLIFICATION AND THE  
DEVELOPMENT OF DEEP SOUTHWESTERLY RETURN FLOW ACROSS SOUTHEAST  
MICHIGAN. CURRENT INDICATIONS ARE THAT FAR SOUTHERN STREAM PV  
ANOMALY WILL BE KICKED NORTHEASTWARD WITH TOO MUCH SEPARATION AND  
LITTLE MERGING THROUGH SOUTHEAST MICHIGAN. A VERY WARM SYSTEM, 850MB  
DEWPOINTS OF +8 OR +9C. FROM THIS VANTAGE POINT THERE APPEARS AT  
SOME POTENTIAL FOR NEUTRAL STABILITY TO INSTABILITY BETWEEN 4.0-20.0  
KFT AGL. CONVECTIVE RAINFALL POSSIBLE AND ELEVATED THUNDER MAY BE  
NEEDED IN THE FORECAST THURSDAY NIGHT. CURRENT 75TH PERCENTILE OF  
THE EPS IS ABOUT .40 TO .50 INCH. HIGHS BOTH THURSDAY AND FRIDAY MAY  
RANGE IN THE 40S TO 50S.  
 
AGEOSTROPHIC CIRCULATIONS DEVELOPING IN RESPONSE TO STRONG  
GEOPOTENTIAL HEIGHT FALLS AND CHANGES IN UPPER LEVEL JET STREAK  
CURVATURE IS FORECASTING A DYNAMIC STORM SYSTEM OVER THE REGION THIS  
WEEKEND. UNCERTAINTY EXISTS DUE TO TIMING CONCERNS IN BOTH VORTICITY  
MERGING AND UPPER LEVEL JET PHASING. CURRENT DATA SUGGESTS ANOTHER  
WARM SYSTEM HERE LOCALLY AND THAT IS WHERE THE FORECAST CURRENTLY  
RESIDES. DEPENDING ON THE EVENTUAL TRACK OF THE SURFACE LOW, STRONG  
WIND CONCERNS MAY ARISE. BULK OF WRAP AROUND SNOW CHANCES LOOKS TO  
BE SUNDAY.  
 
 
   
MARINE  
 
LOW PRESSURE LIFTS TOWARD THE SOUTHERN LAKE HURON BASIN THIS  
AFTERNOON-EVENING. ONGOING PRECIPITATION COVERAGE HAS BEEN GREATEST  
NORTH OF THE SYSTEM'S WARM FRONT, WHICH WILL KEEP STEADY RAIN GOING  
INTO TONIGHT. THE MORE WIDESPREAD IMPACT OF THIS LOW HAS BEEN A  
BLANKET OF FOG ACROSS THE GREAT LAKES, WHICH MAY BECOME LOCALLY  
DENSE AT TIMES THIS EVENING. WINDS BECOME MORE UNIFORM BY WEDNESDAY  
MORNING AS THE LOW DEPARTS AND HIGH PRESSURE FILLS IN. THIS SUPPORTS  
A QUIETER MID WEEK PERIOD BEFORE THE NEXT STRING OF LOW PRESSURE  
SYSTEMS IMPACT THE GREAT LAKES FRIDAY INTO THIS WEEKEND. INITIALLY,  
WARM AND STABLE CONDITIONS WILL PREVENT AN OTHERWISE ENERGETIC LOW  
LEVEL JET FROM MIXING TO THE SURFACE TO KEEP WIND GUSTS AROUND 30  
KNOTS OR LESS.  
 
 
   
PREV DISCUSSION  
 
ISSUED AT 1128 AM EST TUE JAN 6 2026  
 
AVIATION...  
 
SFC LOW PRESSURE WILL MOVE ACROSS THE NORTHERN DETROIT METRO  
AIRSPACE IN THE 20Z TO 23Z TIME FRAME. PERSISTENT ELEVATED FRONTAL  
FORCING WILL SUSTAIN RAIN ACROSS PTK/FNT/MBS THROUGH THE AFTERNOON,  
WITH OCCASIONAL DRIZZLE/LIGHT RAIN IMPACTING THE METRO DETROIT  
TERMINALS. ONGOING MOISTURE ADVECTION INTO THIS LOW PRESSURE SYSTEM  
WILL SUSTAIN IFR CONDITIONS INTO TONIGHT. A FEW AREAS OF LIFR  
CONDITIONS ARE ALSO EXPECTED. WHILE THE LOW PRESSURE SYSTEM WILL  
DEPART TO THE EAST TONIGHT, LINGERING MOISTURE WRAPPING AROUND THE  
BACK SIDE OF THE SYSTEM WILL SUSTAIN LOW CLOUDS THROUGH THE NIGHT,  
WITH A DEEPENING SUBSIDENCE INVERSION LIKELY TO HOLD A IFR AND/OR  
MVFR BASED STRATUS DECK INTO WEDNESDAY. LINGERING LIGHT RAIN WITHIN  
THE WRAP AROUND MOISTURE MAY MIX WITH OR CHANGE OVER TO SNOW TONIGHT  
UNDER SUBTLE LOW LEVEL COOLING.  
 
FOR DTW...THE PROXIMITY TO THE HIGHER MOISTURE FEEDING INTO THE LOW  
PRESSURE SYSTEM MAY DRIVE CEILINGS AND/OR VISIBILITY DOWN TOWARD 200  
FT AND/OR 1/2SM THIS AFTERNOON AND EARLY EVENING. OBSERVATIONAL  
TRENDS SUGGEST THIS MAY BE BRIEF, BUT WILL WARRANT A TEMPO FOR  
CONDITIONS NEAR THESE THRESHOLDS.  
 
DTW THRESHOLD PROBABILITIES...  
 
* HIGH FOR CEILING 5000 FEET OR LESS TODAY THROUGH WEDNESDAY.  
 
* LOW FOR CEILINGS AND/OR VISIBILITIES AT OR BELOW 200 FEET AND/OR  
1/2 SM.  
 
 
   
DTX WATCHES/WARNINGS/ADVISORIES  
 
MI...DENSE FOG ADVISORY UNTIL 9 PM EST THIS EVENING FOR MIZ060>063-  
068>070-075-076-082-083.  
 
LAKE HURON...NONE.  
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  
 
 
 
 
DISCUSSION...CB  
MARINE.......MV  
AVIATION.....SC  
 
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