620
FXUS63 KDTX 100521
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1221 AM EST SAT JAN 10 2026
KEY MESSAGES
- ACCUMULATING SNOW IS EXPECTED ACROSS MUCH OF SOUTHEAST MICHIGAN
SATURDAY AFTERNOON AND SATURDAY NIGHT. SNOWFALL AMOUNTS WILL VARY
WITH 1 TO 3 INCHES POSSIBLE ALONG AND NORTH OF I 69. HIGHEST AMOUNTS
WILL BE POSSIBLE OVER MIDLAND, BAY AND HURON COUNTIES. LESSER
AMOUNTS ARE EXPECTED TO THE SOUTH ACROSS METRO DETROIT WITH THE
POTENTIAL FOR MELTING.
- THERE IS A CHANCE FOR SNOW SHOWERS WITH SOME BRIEF SNOW SQUALLS
SATURDAY NIGHT AND EARLY SUNDAY MAINLY ALONG AND SOUTH OF I 96. LOW
CONFIDENCE IN TIMING AND COVERAGE.
- NORTHWEST WINDS OF 30 TO 35 MPH WILL BE POSSIBLE SUNDAY.
- BELOW NORMAL TEMPERATURES DEVELOPING FOR THE MIDDLE TO END OF NEXT
WEEK.
AVIATION
LOWER COLUMN FLOW HAS STARTED TO RESPOND TO EXPANDING SUBSIDENCE
OVER LOWER MICHIGAN LEADING TO THE EROSION OF BKN-OVC MVFR LAKE-
MODIFIED STRATOCUMULUS DECK BENEATH A PASSING WEAK SHORTWAVE RIDGE.
INCORPORATED SOME TEMPOS FOR A PERIOD OF PARTIAL SCATTERING, BUT
ANOTHER PLUME OF LOW-LEVEL MOISTURE IS STILL LIFTING NORTHWARD
ACROSS THE MI/OH BORDER, THEREFORE INCORPORATED ADDITIONAL MVFR
CEILINGS FOR THE SOUTHERN TAF SITES. THE NEXT LOW PRESSURE SYSTEM IS
ALREADY APPROACHING FROM THE WEST, BUT EXPECT THAT IT WILL TAKE
UNTIL SATURDAY AFTERNOON FOR CEILINGS TO FULLY FILL BACK IN AND
LOWER TO MVFR OR IFR, THEN VISIBILITIES DECREASE ACCORDINGLY AFTER
PRECIPITATION STARTS. SITES FROM PTK NORTH ARE MORE LIKELY TO REMAIN
ALL SNOW AT THE START OF THE EVENT, WHILE FURTHER SOUTH, HIGHER
CHANCES EXISTS FOR RAIN, OR A RAIN/SNOW MIX AT ONSET. PRECIPITATION
LIKELY HOLDS OFF UNTIL AFTER 15Z, BEGINNING LATER WITH SOUTHEASTWARD
EXTENT TO AROUND 18Z. THE SYSTEM'S COLD FRONT MOVES THROUGH SATURDAY
EVENING VEERING WINDS WESTERLY. THIS ALSO ACTIVATES COLD ADVECTION,
LEADING TO STEEPER LAPSE RATES AND GUSTY WINDS TO AROUND 25 KNOTS BY
SATURDAY NIGHT.
FOR DTW...MVFR CEILINGS FOR MOST OF TONIGHT, THEN VFR UNTIL SATURDAY
AFTERNOON AS RAIN/SNOW ARRIVES. WINDS BACK WESTERLY SATURDAY NIGHT
WITH MVFR TO IFR CEILINGS AND ADDITIONAL LAKE EFFECT SNOW SHOWERS.
DTW THRESHOLD PROBABILITIES...
* MODERATE FOR CEILING AT OR BELOW 5000 FEET OVERNIGHT, THEN HIGH
SATURDAY AFTERNOON AND EVENING.
* MODERATE FOR RAIN/SNOW MIX SATURDAY AFTERNOON, THEN HIGH
FOR SNOW SATURDAY EVENING/NIGHT.
PREV DISCUSSION
ISSUED AT 305 PM EST FRI JAN 9 2026
DISCUSSION...
NON-CONVECTIVE PEAK WINDS OF 55 TO 65 MPH OCCURRED OVER A GREATER
PORTION OF THE SOUTHERN FORECAST AREA FROM DETROIT SOUTHWARD IN AN
APPROXIMATE 60 MINUTE PERIOD BETWEEN 1030-1130AM. STEEP LAPSE RATES
THAT RESULTED FROM THE COMBINATION OF DAYTIME HEATING AND THE
INITIAL NEAR SURFACE COLD ADVECTION ALLOWED FOR THE EFFICIENT
DOWNWARD MOMENTUM TRANSPORT OF THE STRONG KINEMATIC PROFILE ALOFT.
OVER THE NEXT HOUR, A SECONDARY WIND SHIFT TO THE NORTHWEST WILL
OCCUR ALONG THE TRAILING TROUGH AXIS. FORECASTED WIND FIELDS PROJECT
SOME LINGERING GUSTY WIND POTENTIAL THE NEXT HOUR BEFORE FALLING
OFF/WEAKENING RAPIDLY BY 22Z. THE WIND ADVISORY WILL BE ALLOWED TO
EXPIRE AT 4PM.
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION, ANTICYCLONIC CURVATURE TO
THE UPPER LEVEL JET AXIS, AND DOWNSTREAM SHORTWAVE RIDGING WILL
SUPPORT SURFACE HIGH PRESSURE OVER SOUTHEAST MICHIGAN TONIGHT. PLAN
VIEW OF RELATIVE HUMIDITY ON ISENTROPIC SURFACES SUPPORTS DEEP DRY
AIR ADVECTION WITH WELL DEFINED SYSTEM RELATIVE ISENTROPIC DOWNGLIDE
THROUGH 12Z SATURDAY MORNING. SOME LIGHT BR/HZ WILL BE POSSIBLE
AROUND DAYBREAK WITH LIGHT WINDS, BUT NO SIGNIFICANT SIGNAL EXISTS
FOR DENSE FOG.
IMPRESSIVE MERGER OF TWO ABSOLUTE VORTICITY CENTERS WILL CAUSE
CYCLOGENESIS OVER LOWER MICHIGAN LATE SATURDAY AFTERNOON AND
SATURDAY NIGHT. THE MOST NOTABLE ASPECT OF THE SYSTEM IS AN
EXTREMELY PROGRESSIVE AND DOMINANT UPPER LEVEL JET STREAK THAT
FLASHES EASTWARD CARRYING THE GREATEST HEIGHT FALLS THROUGH OHIO/PA
BEFORE TRANSFERRING CYCLOGENESIS TO THE EAST COAST. LOCALLY, THE NET
RESULT IS A PSEUDO BAROTROPIC LOW PRESSURE SYSTEM THAT WILL HAVE AT
LEAST SOME BRIEF WARM CONVEYOR CONNECTION. THE FORECAST QUESTION FOR
THE SATURDAY SYSTEM NOW APPEARS TO HAVE EVOLVED TOWARD ONE OF QPF
AMOUNTS. MIDLEVEL MOISTURE PROGS OUT OF BOTH THE 09.12Z GFS AND NAM
SUGGEST A 6-8 HOUR PERIOD OF MIDLEVEL MOISTURE/SATURATION THAT WILL
SWING THROUGH SOUTHEAST MICHIGAN BEFORE MIDLEVEL DRY SLOT LIFTS
NORTHWARD AGAIN THROUGH ALL OF THE CWA. THE 00Z CONTROL RUN OF THE
ECMWF AND THE GREATER 06Z EPS SUITE WERE SIGNIFICANT OUTLIERS WITH
DEEPER MOISTURE AND A LONGER PRECIPITATION DURATION DUE TO PERSISTENT
TROWAL/DEFORMATION FORCING. THE LATEST 09.12Z CONTROL RUN OF THE
ECMWF HAS SINCE BACKED OFF THIS SOLUTION. MARKED DIFFERENCES EXIST IN
QPF AND SNOW AMOUNTS BETWEEN NBM V5.0 AND NBM V4.3. PREFERENCE IS
SIDED WITH A STRONG NWP CONSENSUS FOR LIGHT AMOUNTS OF QPF. THIS DOES
REMAIN IN GOOD AGREEMENT WITH THE INHERITED GRIDS.
THE OTHER TREND IS FOR A COLDER SOLUTION SPACE SUPPORTING SNOW AS A
PRECIPITATION TYPE SATURDAY NIGHT AND SUNDAY. CONSENSUS OF MODEL
SOLUTIONS SHOWS A VERY STRONG WET BULB COOLING POTENTIAL BETWEEN 2.0
AND 5.0 KFT AGL FOR ALL AREAS INCLUDING SOUTHERN METRO DETROIT.
FORECASTED SURFACE TEMPERATURES STILL REMAIN MILD FOR THE DAYTIME,
BUT FORECAST SOUNDINGS SUGGEST IT WILL BE EXTREMELY SHALLOW. PEAK OF
THE EVENT APPEARS BETWEEN 16Z SAT AND 00Z SUNDAY. THE POTENTIAL THEN
EXISTS FOR SHOW SHOWERS AND OR BRIEF SNOW SQUALLS SATURDAY NIGHT AS
THE VORTICITY MAX TRACKS DIRECTLY THROUGH FAR SOUTHERN LOWER
MICHIGAN. UNCERTAINTY EXISTS ON COVERAGE DUE TO MESOSCALE PROCESSES
THAT WILL LIKELY HAVE INTERACTION WITH CONVERGENCE PULLING AWAY FROM
LAKE MICHIGAN. WRAP AROUND SNOW CHANCES WILL THEN BE POSSIBLE SUNDAY.
LOW CONFIDENCE ON COVERAGE AGAIN SUNDAY AS LATEST MODEL DATA
SUGGESTS COMPOSITE TROUGH AXIS WILL ALREADY BE DRIFTING EAST OF THE
CWA. GEOPOTENTIAL HEIGHTS FILLING WITH A TRANSITION TO CONFLUENCE
ALOFT SHOULD SUPPORT SYNOPTIC SCALE SUBSIDENCE LATE SUNDAY. THE
MESSAGING FOR THIS EVENT WILL BE 1 TO 3 INCHES OF SNOWFALL POSSIBLE
FOR AREAS ALONG AND NORTH OF I 69 WITH HIGHEST AMOUNTS EXPECTED IN
BAY AND MIDLAND COUNTIES. LESS THAN 2 INCHES OF SNOWFALL IS EXPECTED
SOUTH OF I 69 BUT THAT WILL ACCOUNT FOR THE ENTIRE 24 HOUR PERIOD
18Z SATURDAY TO 18Z SUNDAY.
STRONG NORTHWEST GRADIENT FLOW IN THE WAKE OF THE SYSTEM WILL BRING
ANOTHER PERIOD OF STRONGER WINDS TO SOUTHEAST MICHIGAN SUNDAY. A
WEAKER KINEMATIC FIELD THAN THIS PREVIOUS SYSTEM WITH LESS DYNAMIC
FRONTAL PASSAGE LIMITS THE FORECASTED WINDS INTO THE 30 TO 35 MPH
RANGE. CONFLUENCE ALOFT SHOULD LEAD TO QUIET HIGH PRESSURE MONDAY
BEFORE A SERIES OF TROUGHS BEGIN TO DESCEND INTO THE GREAT LAKES
TUESDAY AND THE MIDDLE OF NEXT WEEK.
MARINE...
A COLD FRONT HAS NOW CLEARED THE GREAT LAKES WHICH WILL SUSTAIN
BREEZY NORTHWEST FLOW INTO THE EVENING. THE BETTER COLD AIR
ADVECTION AND THUS REGION OF ENHANCED OVER LAKE INSTABILITY WILL
RESIDE ACROSS NORTHERN AND CENTRAL LAKE HURON, WHICH WILL MAINTAIN
GUST TO GALES THROUGH THE EVENING. HIGH PRESSURE DOES RAPIDLY FILL
IN ACROSS THE REGION LATE TONIGHT INTO TOMORROW MORNING, WHICH WILL
QUICKLY DIMINISH WIND POTENTIAL, LEADING TO LIGHT WINDS OVERNIGHT.
A SECOND LOW PRESSURE SYSTEM WILL THEN MOVE THROUGH STARTING
SATURDAY WHICH WILL BRING WIDESPREAD SNOW TO THE GREAT LAKES.
DEPARTURE OF THIS LOW INTO CANADA WILL BRING ANOTHER COLD FRONT
ACROSS THE REGION WITH A RENEWED PUSH OF COLD AIR AIR WHICH WILL
BRING ELEVATED WINDS THROUGH SUNDAY. GUSTS AROUND 30 KNOTS ARE
INCREASINGLY LIKELY ACROSS PORTIONS OF LAKE HURON BY SUNDAY MORNING,
WITH SOME LOW-END CHANCES FOR GUST TO GALES THROUGH THE CENTRAL AND
SOUTHERN BASIN. SMALL CRAFT ADVISORIES WILL BE LIKELY ACROSS THE
OUTER SAGINAW BAY THROUGH NORTHERN THUMB AS NORTHWEST FLOW BRINGS
ELEVATED WAVE HEIGHTS. A BRIEF RIDGE OF HIGH PRESSURE BUILDS IN LATE
SUNDAY TO MONDAY MORNING, DECREASING WIND SPEEDS WHILE WINDS BACK TO
THE SOUTHWEST.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...GALE WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR LHZ363-
462>464.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM EST SUNDAY FOR
LHZ421-441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....KGK
DISCUSSION...CB
MARINE.......AM
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