515
FXUS63 KDTX 070525
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1225 AM EST WED JAN 7 2026
KEY MESSAGES
- 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.
AVIATION
IFR TO BORDERLINE LIFR CONDITIONS REMAIN ENTRENCHED ACROSS THE
TERMINALS TONIGHT AS A SURFACE LOW EXITS SOUTHERN LOWER MICHIGAN.
PERSISTENT LOW-LEVEL SATURATION WITH WEAK ASCENT HAS ENSURED A MIX
OF THINNING FOG AND RAIN/DRIZZLE/SNOW THROUGH EARLY TONIGHT, MAINLY
FROM PTK NORTH. CONDITIONS WILL ONLY IMPROVE SLIGHTLY OVERNIGHT,
STILL HOLDING IFR FOR MOST SITES INTO WEDNESDAY MORNING. WINDS
REORIENT WESTERLY BEHIND THE DEPARTING LOW WHICH HELPS USHER IN
SLIGHTLY LESS HUMID AIR, THEREFORE VISIBILITIES ARE EXPECTED TO
IMPROVE PRIOR TO CEILINGS GIVEN UPSTREAM TRENDS. CEILINGS HOLD IN
THE LOW MVFR RANGE THROUGH MOST OF THE DAYLIGHT HOURS BEFORE LIFTING
ABOVE 2 KFT AGL AND EVENTUALLY SCATTERING OUT WEDNESDAY EVENING AS
FLOW BACKS SOUTHWESTERLY. POTENTIAL EXISTS FOR AREAS OF SKC
WEDNESDAY NIGHT.
FOR DTW...PREDOMINANTLY IFR, THEN LIFTING TO MVFR FOR MOST OF
WEDNESDAY. PRECIPITATION IS GENERALLY OVER, BUT A BIT OF ADDITIONAL
LIGHT DRIZZLE (LIQUID) REMAINS POSSIBLE BEFORE SUNRISE.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING AT OR BELOW 5000 FEET THROUGH WEDNESDAY EVENING.
* LOW FOR CEILINGS AND/OR VISIBILITIES AT OR BELOW 200 FEET AND/OR
1/2 SM THE REST OF THE EVENING.
PREV DISCUSSION
ISSUED AT 323 PM EST TUE JAN 6 2026
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.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....KGK
DISCUSSION...CB
MARINE.......MV
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