269
FXUS63 KDTX 172037
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
337 PM EST WED DEC 17 2025
KEY MESSAGES
- MILD WITH HIGH TEMPS IN THE MID 40S TO AROUND 50 DEGREES ON
THURSDAY.
- WIDESPREAD RAINFALL IS EXPECTED ON THURSDAY, ALONG WITH GUSTY
WINDS OF 30-40 MPH INTO FRIDAY AS WELL.
- THERE IS THE POTENTIAL FOR ANY MOISTURE ON ROADWAYS TO FLASH
FREEZE THURSDAY NIGHT AS ARCTIC AIR MOVES BACK INTO THE REGION.
- SCATTERED-NUMEROUS LIGHT SNOW SHOWERS THURSDAY NIGHT-FRIDAY
MORNING, WITH ISOLATED EMBEDDED SNOW SQUALLS POSSIBLE INTO THE
AFTERNOON. SNOWFALL ACCUMULATIONS UP TO AN INCH IN THE HEAVIEST
ACTIVITY. EXPECT THE FRIDAY MORNING COMMUTE TO BE IMPACTED AND ALLOW
FOR EXTRA TIME.
DISCUSSION
THE ACTIVE AND PROGRESSIVE JET STREAM ACROSS THE NORTHERN TIER OF
THE CONUS WILL CONTINUE THROUGH THE FORECAST PERIOD WITH ONE OF THE
STRONGEST, MOST DYNAMIC SYSTEMS IN A FEW WEEKS IMPACTING THE REGION
TOMORROW INTO FRIDAY. THIS SYSTEM WILL BRING ABOVE NORMAL
TEMPERATURES AND MODERATE RAINFALL THURSDAY, BOTH OF WHICH WILL AIDE
IN SNOW MELT, AND ALSO ELEVATED WINDS THURSDAY AND FRIDAY, RAPIDLY
FALLING TEMPS THURSDAY NIGHT WITH LIGHT SNOW AND POSSIBLY SQUALLS
INTO FRIDAY BEFORE FINALLY SETTLING DOWN FOR THE WEEKEND.
TEMPERATURES WERE ABLE TO TOUCH 40 AT MOST LOCATIONS ACROSS SE MI
TODAY AS HEIGHTS ROSE A BIT BEHIND THIS MORNINGS TROUGH, AIDED BY
CLEARING SKIES. AS THE UPPER LEVEL TROUGH DIGS INTO THE PLAINS
TONIGHT AND DEEPENS WITH THE INBOUND 160 KNOT UPPER LEVEL JET,
DOWNSTREAM RIDGE AMPLIFICATION WILL LEAD TO MORE RAPIDLY BUILDING
HEIGHTS AND WARM AIR ADVECTION WITH STRONG SOUTHERLY LOW LEVEL JET
KICKING IN SO EXPECTING HIGHS INTO THE MID TO UPPER 40S THURSDAY.
SOME SOUTHERN LOCATIONS MAY TOUCH 50 AS WELL.
THURSDAY WILL ALSO BE A WET DAY WITH PREFRONTAL RAIN DEVELOPING
THROUGH THE DAY AND POSSIBLE CONVECTIVE RAIN ALONG THE STRONG COLD
FRONT IN THE EVENING. LOCAL PROBABILISTIC GUIDANCE SHOWS ABOVE AN
80% CHANCE FOR ALL LOCATIONS TO RECEIVE A QUARTER INCH OF RAINFALL
FROM ABOUT 18-06Z AND MAINLY LESS THAN A 20% CHANCE TO REACH A HALF
INCH. NATIONAL GUIDANCE FALLS IN LINE WITH THIS AS THE MEAN VALUE
FOR THE 12 HOUR PERIOD IS ROUGHLY 0.3-0.4 INCHES WITH 90% PERCENTILE
VALUES REACHING 0.5-0.6 INCHES. SO CURRENT FORECAST FOR AROUND 0.4
IS VERY REASONABLE. ADDING SNOW MELT WHICH CURRENTLY HOLDS AROUND 0.5-
1.0 INCHES OF WATER, DO EXPECT SOME RISES IN LOCAL WATERWAYS BUT
CURRENT GUIDANCE SUGGESTS IT WON'T BE ENOUGH TO CAUSE FLOODING.
FRONTAL PASSAGE IN THE EVENING THEN OPENS THE DOOR FOR RAPID COOLING
WITH 850MB TEMPS DROPPING FROM 6C AT 00Z, -2C AT 06Z AND -11C BY
12Z. RESIDUAL WATER ON ROADS MAY RAPIDLY FREEZE AS AIR TEMPS QUICKLY
DROP INTO THE MID TO UPPER 20S AFTER DARK. ADDITIONALLY, THE STRONG
COLD WESTERLY WINDS WILL EXCITE LAKE EFFECT WITH BANDS OF SNOW
WORKING EAST ACROSS LOWER MI. STILL NO REAL STRONG SIGNAL WITH LOW
LEVEL CONVERGENCE WHICH WOULD SUGGEST HIGHER CONFIDENCE FOR ANY
CORRIDOR TO OVERACHIEVE WITH LAKE EFFECT BANDS SETTING UP. STILL,
STRONG WINDS AND SNOW OVERNIGHT THURSDAY INTO FRIDAY MORNING WILL
OFFER A CHANCE FOR BRIEF SNOW SQUALLS. CURRENTLY ONLY THINKING
AROUND A HALF INCH OF SNOW IS MOST LIKELY AS MIXING DEPTHS ARE
TOPPING OUT AROUND 5KFT. THOUGH THIS DOES PASS THROUGH THE DGZ, IT'S
A BIT SHALLOWER THAN WE'D LIKE TO SEE FOR HIGHER END LAKE EFFECT.
AS BRIEFLY MENTIONED, WINDS WILL BE ELEVATED THURSDAY AND FRIDAY.
THURSDAY WILL BE PREFRONTAL SOUTH/SOUTHEASTERLY WINDS BUT A STRONG
INVERSION WILL PREVENT MIXING DOWN THE STRONGEST OF WINDS WITH MOST
MODELS TOPPING GUSTS OFF AROUND 20-30 MPH OVER LAND. FRIDAY WINDS
WILL BE STRONGER AS THE COLD ADVECTION HELPS MIXING DEPTHS INCREASE
TO AROUND 5KFT. PROBABILISTIC GUIDANCE SHOWS THE ONLY CHANCE (LESS
THAN 20%) FOR THE NORTHERN THUMB TO HIT 45 MPH WITH GUSTS. MOST OF
THE GUIDANCE CENTERS IN THE 30-40 MPH RANGE. SO AN ISOLATED GUST
COULD REACH WIND ADVISORY CRITERIA, BUT DOESN'T LOOK TO BE THE NORM.
HIGH PRESSURE BUILDS BACK ACROSS THE OHIO VALLEY AND UP INTO MI
THROUGH THE DAY FRIDAY AND LINGERING THROUGH SATURDAY. THIS WILL BE
SHORT LIVED THOUGH AS THE PROGRESSIVE PATTERN HOLDS AND THE NEXT LOW
TRACKING THROUGH ONTARIO BRINGS THE NEXT COLD FRONT THROUGH LOWER MI
SATURDAY EVENING OR OVERNIGHT.
MARINE
QUIET CONDITIONS PERSIST THROUGH THE EVENING, FOLLOWED BY WINDS
QUICKLY ORGANIZING OUT OF THE SOUTH OVERNIGHT AS LOW PRESSURE TRACKS
ALONG THE CONUS-CANADA BORDER. LOW LEVEL WINDS AHEAD OF THIS LOW
INTENSIFY RAPIDLY THURSDAY, APPROACHING 70 KNOTS AT 850MB. WARM AND
STABLE CONDITIONS PREVENT THIS MAGNITUDE OF WINDS FROM REACHING THE
SURFACE, BUT EVEN THE SHALLOW MIXING DEPTHS WILL STILL BE CAPABLE OF
35-40 KNOT GUSTS ACROSS THE OPEN WATERS. A GALE WARNING HAS BEEN
ISSUED AS A RESULT. HIGHER STABILITY TOWARD THE SHORELINE KEEPS
GUSTS AROUND 30 KNOTS, ALTHOUGH OVERACHIEVEMENT IN MIXING MAY
REQUIRE AN OBSERVATION-BASED UPGRADE FOR THE NEARSHORE ZONES. THE
LOW EVENTUALLY DRAWS A COLD FRONT ACROSS THE GREAT LAKES THURSDAY
EVENING, AFFORDING A BRIEF LULL IN WIND GUSTS BEFORE RAMPING BACK UP
EARLY FRIDAY MORNING AS STRONG COLD ADVECTION BEGINS. THE COLDER AIR
ERODES STABILITY TO SUPPORT A SECOND WAVE OF GALE FORCE GUSTS, THIS
TIME OUT OF THE WEST-NORTHWEST AND FOR BOTH THE NEARSHORE AND OPEN
WATERS. IN ADDITION TO WIND/WAVE CONCERNS, THE FRONT WILL ALSO FOCUS
A BAND OF RAIN SHOWERS ACROSS THE GREAT LAKES THURSDAY EVENING
FOLLOWED BY A TRANSITION TO LAKE ENHANCED SNOW FOR FRIDAY. SNOW
SQUALLS WILL BE POSSIBLE GIVEN THE GUSTY WINDS. HIGH PRESSURE THEN
ARRIVES FRIDAY NIGHT, BRINGING A BRIEF REPRIEVE FROM THE ACTIVE
STRETCH, ALTHOUGH YET ANOTHER LOW PRESSURE SYSTEM TRACKS THROUGH
ONTARIO SATURDAY NIGHT-SUNDAY WHICH CARRIES ADDITIONAL GALE
POTENTIAL.
HYDROLOGY
MILDER TEMPERATURES BRING SNOW MELT ACROSS THE AREA AND WIDESPREAD
RAINFALL IS EXPECTED THURSDAY FROM LATE MORNING INTO THE EVENING.
MAXIMUM SNOW WATER EQUIVALENT IN THE DEEPER SNOW PACK IS CURRENTLY
AROUND 1 INCH. BASIN AVERAGE RAINFALL TOTALS AROUND HALF AN INCH ARE
EXPECTED, WHICH WITH THE SNOW MELT MAY LEAD TO PONDING ON ROADWAYS.
RISES ON AREA RIVERS ARE LIKELY LATE THIS WEEK, BUT FLOOD CONDITIONS
ARE NOT ANTICIPATED.
PREV DISCUSSION
ISSUED AT 1249 PM EST WED DEC 17 2025
AVIATION...
A RIDGE OF HIGH PRESSURE PASSING TO THE SOUTH MAINTAINS A LOW-LEVEL
INVERSION THAT CONTINUES TO LOWER SLIGHTLY THIS AFTERNOON,
MAINTAINING POTENTIAL FOR MVFR CEILINGS AT TIMES. THINKING THE
STRATUS WILL BEGIN TO SCATTER AND TREND TO VFR BY THIS EVENING.
WESTERLY WIND WILL BACK TO SOUTHERLY TONIGHT AND STRENGTHEN
CONSIDERABLY OVERNIGHT IN ADVANCE OF A STRONG LOW PRESSURE SYSTEM
TRACKING IN FROM THE WEST ON THURSDAY. A CORE OF 50+ KT FLOW WITHIN
THE LOWEST 1.5 TO 2 KFT WILL ARRIVE EARLY THURSDAY MORNING, LEADING
TO LLWS CONCERNS BEFORE THE SURFACE LAYER WIND INCREASES AND
MITIGATES THE SHEAR. THIS SPEED MAX ALOFT PEAKS DAYTIME THURSDAY AT
60+ KT, WITH SURFACE GUSTS EXCEEDING 30 KT. WIDESPREAD RAIN WILL
ARRIVE FROM THE SOUTH AND WEST DURING THE MORNING, WITH MVFR THEN
IFR CONDITIONS EXPECTED FIRST IN THE SAGINAW VALLEY BY AROUND NOON,
THEN SPREADING ACROSS THE REST OF THE AREA LATER IN THE DAY.
FOR DTW...CEILING TRENDS THIS AFTERNOON CARRY A HIGH AMOUNT OF
UNCERTAINTY. LLWS WILL BECOME LIKELY AFTER AROUND 08Z AND MAY
PERSIST LONGER INTO THE MORNING DEPENDING ON HOW WINDY THE SURFACE
LAYER BECOMES. HIGH CONFIDENCE IN ALL RAIN THROUGH 00Z FRI.
DTW THRESHOLD PROBABILITIES...
* MODERATE IN CEILINGS AOB 5000 FEET TODAY. HIGH AFTER 10Z THURSDAY
MORNING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...GALE WARNING FROM MIDNIGHT TONIGHT TO 7 PM EST FRIDAY FOR
LHZ361>363-462.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST THURSDAY
NIGHT FOR LHZ421-441>443.
GALE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY EVENING FOR
LHZ421-422-441>443.
LOW WATER ADVISORY FROM 7 AM THURSDAY TO 7 PM EST FRIDAY FOR LHZ422.
SMALL CRAFT ADVISORY FROM 7 AM THURSDAY TO MIDNIGHT EST THURSDAY
NIGHT FOR LHZ422.
GALE WARNING FROM 7 AM THURSDAY TO 7 PM EST FRIDAY FOR LHZ463-464.
LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 7 AM THURSDAY TO 7 PM EST FRIDAY FOR
LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 7 AM THURSDAY TO 7 PM EST FRIDAY FOR
LEZ444.
DISCUSSION...DRK
MARINE.......MV
HYDROLOGY....SF
AVIATION.....TF
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