854
FXUS63 KDTX 170134
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
834 PM EST SUN FEB 16 2025
KEY MESSAGES
- BECOMING COLDER LATE TONIGHT WITH LOWS IN THE UPPER SINGLE DIGITS
TO LOW TEENS, AND WITH WINDS HOLDING IN THE 10-15 MPH RANGE, WIND
CHILLS MINIMIZE AROUND ZERO IF NOT NEGATIVE SINGLE DIGIT TERRITORY
BY SUNRISE MONDAY MORNING.
- ADDITIONAL LAKE EFFECT SNOW SHOWERS ARE POSSIBLE MONDAY WITH MINOR
ACCUMULATIONS BEFORE DRIER WEATHER SETTLES IN TUESDAY AND EARLY
WEDNESDAY.
- ADDITIONAL LIGHT SNOWFALL CHANCES WEDNESDAY EVENING INTO THURSDAY
MORNING WITH WELL BELOW NORMAL TEMPERATURES UNTIL LATE THIS WEEKEND.
UPDATE
SINCE THE LOSS IN DIURNAL MIXING POST SUNSET, REMNANT SNOW SHOWERS
HAVE DEVELOPED INTO MORE DOMINATE BANDED STRUCTURES, MOST NOTABLY
ALONG THE I-75 CORRIDOR. DEEP LAYER MOISTURE OVERHEAD WILL EXIT TO
THE EAST DURING THE REMAINDER OF THE EVENING. THIS WILL FURTHER
DIMINISH THE COVERAGE OF SNOW SHOWERS/FLURRIES. SCATTERED SNOW SHOWERS
WILL BECOME FOCUSED ACROSS THE SOUTHERN PORTIONS OF THE AREA
OVERNIGHT AS THE LOW LEVEL FLOW BACKS A LITTLE MORE TOWARD THE WEST-
NORTHWEST. INVERSION HEIGHTS ACROSS SOUTHERN LAKE MICHIGAN WILL
REMAIN BELOW 6K FEET. HOWEVER, GOOD MOISTURE AROUND THE -16 TO -20C
LAYER SHOULD BE EFFECTIVE AT GENERATING LIGHT SNOW SHOWERS WITHIN THE
LAKE MOISTURE PLUME. A FORECAST UPDATE WAS ISSUED TO DO SOME MINOR
UPWARD ADJUSTMENTS TO SNOW SHOWER COVERAGE.
PREV DISCUSSION
ISSUED AT 554 PM EST SUN FEB 16 2025
AVIATION...
A STEADY WESTERLY FLOW WILL PREVAIL THROUGH THE TAF PERIOD WHILE
ARCTIC AIR CONTINUES ITS INTRUSION INTO SE MI. MVFR AND SOME IFR
CONDITIONS IN FLURRIES AND LIGHT SNOW SHOWERS WILL PERSIST THROUGH
ROUGHLY 03 TO 04Z BEFORE THE AXIS OF DEEP LAYER MOISTURE OVERHEAD
EXITS TO THE EAST. THE LAKE MICHIGAN MOIST PLUME WILL STILL SUSTAIN
SOME SEMBLANCE OF STRATO CU ACROSS SE MI TONIGHT, MAINLY VFR BASED.
SOME PARTIAL CLEARING DOES LOOK POSSIBLE TOWARD DAYBREAK IN LIGHT OF
THE DEGREE OF DRY AIR ARRIVING WITH THIS ARCTIC AIRMASS. THE ONSET
OF DIURNAL MIXING ON MONDAY WILL SUPPORT SOME REDEVELOPMENT OF THE
LAKE MICHIGAN MOISTURE PLUME INTO A SOLID STRATO CU DECK, ALSO
SUPPORTING A CHANCE OF SOME FLURRIES AND SNOW SHOWERS. THE
PERSISTENCE OF THE COLD AIR ADVECTION WILL SUSTAIN SOME DEGREE OF LOW
LEVEL MIXING AND GUSTINESS TO THE WESTERLY WINDS.
FOR DTW...LINGERING BRIEF BUT HIGHER INTENSITY SNOW SHOWERS CAN BE
EXPECTED ACROSS METRO FOR THE FIRST HOUR OR SO OF TAF ISSUANCE BASED
ON RECENT RADAR TRENDS.
DTW THRESHOLD PROBABILITIES...
* MEDIUM IN CEILING AT OR BELOW 5000 FEET THROUGH THE TAF PERIOD.
* LOW IN CROSSWIND THRESHOLDS BEING MET TONIGHT AND MONDAY.
PREV DISCUSSION...
ISSUED AT 346 PM EST SUN FEB 16 2025
DISCUSSION...
AMPLIFIED UPPER LEVEL TROUGH CONTINUES TO PIVOT INTO THE NORTHEAST
TODAY CAUSING WINDS ALOFT TO VEER TOWARD THE NORTHWEST WITH TIME
OVER THE GREAT LAKES. IN THE LOWER LEVELS, AND IN RESPONSE TO THE
DEPARTURE OF THE CLOSED LOWER COLUMN CIRCULATION, WINDS BACK
NORTHWESTERLY WHICH SUPPORTS THE ADVECTION OF A LAKE AGGREGATE
THETAE PLUME FURTHER INLAND. THE COMBINATION OF IMPINGING LOW-LEVEL
ARCTIC AIRMASS AND DUCTED LAKE MOISTURE WITHIN THE 3-5 KFT AGL LAYER
LOCATED BENEATH A SUBSIDENCE/ISOTHERMAL LAYER HAS SUPPORTED
ADDITIONAL LIGHT SNOWFALL THIS AFTERNOON AND INTO THE EVENING HOURS.
A SURVEY OF REPRESENTATIVE SOUNDINGS SUGGESTS SHALLOW, BUT
SUFFICIENT, DGZ SUPERSATURATION WRT ICE AND IMPROVING OMEGA/ASCENT
PERSISTS THIS EVENING (AND PROBABLY EARLY TONIGHT) TO GENERATE SOME
LIGHT ACCUMULATING SNOWFALL. THIS ALIGNS WITH KGRR/KDTX/CASET RADAR
TRENDS IN SUSTAINING A BROAD PLUME WITHIN THE MODIFIED MIXED LAYER.
MAIN QUESTIONS RELATE TO THE EFFICIENCY OF THE SLRS WHICH ARE
PROJECTED TO HOLD ABOVE 15:1 GIVEN THE FAVORABLE MICROPHYSICS SETUP,
BUT ALSO THE DURATION INTO THE OVERNIGHT HOURS AS THE FLOW
EVENTUALLY ORIENTS NORTHWESTERLY. OVERALL, CONSENSUS QPF/SLR SUGGEST
NEW SNOWFALL OF AROUND A HALF INCH FOR MOST AREAS NORTH OF I-94, BUT
AREAS ACROSS THE THUMB AND SOUTHERN LAKE HURON SHORELINE COULD
CONCLUDE WITH NEW AMOUNTS CLOSER TO AN INCH GIVEN THE MORE FAVORABLE
LAKE HURON CONNECTION ALONG CYCLONIC NORTH-NORTHWEST FLOW
TRAJECTORIES. ENHANCED LLJ OF APPROXIMATELY 40 KNOTS AND EFFICIENT
MECHANICAL TURBULENCE OFFER GUSTS IN EXCESS OF 30 MPH FOR THE REST
OF THE DAYLIGHT HOURS.
BECOMING COOLER TONIGHT WITH LOWS IN THE UPPER SINGLE DIGITS NORTH
TO LOW TEENS (FAHRENHEIT) FURTHER SOUTH. WITH MODEST GRADIENT WIND
EXPECTED TO HOLD IN THE 10-15 MPH RANGE, WIND CHILLS WILL MINIMIZE
AROUND ZERO IF NOT NEGATIVE SINGLE DIGIT TERRITORY BY SUNRISE MONDAY
MORNING. GUSTS REMAIN ELEVATED DURING THIS TIME WITH 20-25 MPH GUSTS
CONTINUING TO MIXING DOWN THROUGHOUT THE NIGHT WHICH MAKES FOR A
SHARPER FEEL THAN ACTUAL APPARENT TEMPERATURES.
WESTERLY FLOW ALOFT EFFECTIVELY STRIPS OUT ANY LINGERING MOISTURE
ABOVE 6 KFT AGL AS COLDER THERMAL PROFILES BEGIN TO STABILIZE WITHIN
A PROLONGED ARCTIC AIR INTRUSION. SUB-700 MB FLOW ACHIEVES A WEST-
NORTHWESTERLY POSITION BETWEEN 06Z AND 09Z TONIGHT WHICH
REESTABLISHES A MORE FAVORABLE CONFIGURATION FOR ADDITIONAL LAKE
EFFECT MONDAY OFF THE MICHIGAN BASIN. GIVEN THE CHILLY WATER
TEMPERATURES (0-4C), MOISTURE FLUX SHOULD WILL RELY ON LARGE DELTATS
DUE TO 850 MB TEMPS OF MINUS 23C. STEEP LOW-LEVEL LAPSE RATES AFFORD
SOME DEGREE OF LAKE-INDUCED CAPE, BUT IN THE ABSENCE OF CLEAR
FORCING SIGNAL, THE OVERALL SNOWFALL RESPONSE SHOULD BE KEPT IN-
CHECK. HIGH VARIABILITY IN COVERAGE, INTENSITY, AND DURATION LEADS
TO LOW CONFIDENCE IN TOTAL NEW ACCUMULATIONS AS FLOW-PARALLEL BANDS
COULD BECOME FIXATED. THE POTENTIAL EXISTS FOR POCKETS OF A HALF
INCH OF SNOWFALL OR GREATER. WINDS REMAIN GUSTY MONDAY WITH
WIDESPREAD 25-35 MPH GUSTS, ESPECIALLY WHILE THE BOUNDARY-LAYER
DEPTH IS MAXIMIZED DURING THE AFTERNOON. TEMPERATURES DROP
SIGNIFICANTLY MONDAY NIGHT, ESPECIALLY IF SKIES CLEAR OUT ONCE
ANTICYCLONIC FLOW FILLS INTO THE 925-850 MB LAYER. SOME LOCALES
SHOULD ANTICIPATE WIND CHILLS DROPPING TO AROUND MINUS 10F (PERHAPS
LOWER SHOULD SKC ARISE) LATE MONDAY NIGHT AND EARLY TUESDAY MORNING.
SOME CONSIDERATION WAS MADE FOR A COLD WEATHER ADVISORY, BUT
CONFIDENCE AND SPATIAL EXTENT IS TOO LOW.
1033-1035 MB SURFACE RIDGE WILL FIXATE OVER LOWER MICHIGAN TUESDAY
AND WEDNESDAY WITH LOWER POTENTIAL FOR LAKE EFFECT SNOW. THERMAL
TROUGH RETAINS STRENGTH THROUGH MID-WEEK WITH PERHAPS A BIT OF
WARMING, BUT STILL WELL BELOW NORMAL TEMPERATURES BY SOME 20
DEGREES. RESIDENT HIGH PRESSURE WILL ACT TO DEFLECT THE EFFECTS OF A
LOBE OF PV SPINNING DOWN FROM THE UPPER MIDWEST TOWARD THE OHIO
VALLEY. THIS LEADS TO THE ESTABLISHMENT OF A CLOSED LOW THROUGH THE
UPPER TWO THIRDS OF THE COLUMN WHICH SLINGSHOTS EASTWARD INTO
WEDNESDAY EVENING INTO THURSDAY. ADDITIONAL ACCUMULATING SNOWFALL IS
POSSIBLE WITH THIS SYSTEM, BUT MOST OF THE QPF SHOULD RESIDE SOUTH
OF THE STATE. TEMPERATURES BEGIN TO RECOVER OVER THE WEEKEND.
MARINE...
ARCTIC AIR WILL CONTINUE TO FILL IN ACROSS THE GREAT LAKES THROUGH
MONDAY IN THE WAKE OF A COLD FRONT. THIS WILL SUSTAIN BREEZY
CONDITIONS, PARTICULARLY ACROSS LAKE HURON WITH THE NORTHWEST FLOW,
WHERE GUSTS AROUND 30 KNOTS WILL BE POSSIBLE. THIS WILL ALSO
GENERATE FREEZING SPRAY ACROSS THE GREATER PORTION OF LAKE HURON
THROUGH TUESDAY MORNING, WHERE A FREEZING SPRAY WARNING IS IN PLACE.
LAST, LAKE EFFECT SNOW SHOWERS, INCLUDING SNOW SQUALLS, WILL BE
LIKELY THROUGH TUESDAY. SNOW SQUALL POTENTIAL WILL PEAK LATE MONDAY
MORNING INTO EARLY TUESDAY MORNING OVER NORTH AND CENTRAL LAKE
HURON, TIED TO THE FAVORABLE NORTHWEST FETCH AND COLDEST PUSH OF
ARCTIC AIR. THE PRESSURE GRADIENT WILL DECREASE IN INTENSITY THROUGH
THE MIDWEEK WHICH WILL DIMINISH WIND SPEEDS AND GUST POTENTIAL.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST TUESDAY FOR LHZ361>363.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST TUESDAY FOR LHZ462-463.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
UPDATE.......SC
AVIATION.....SC
DISCUSSION...KGK
MARINE.......AM
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