271
FXUS63 KDTX 200842
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
342 AM EST THU FEB 20 2025
KEY MESSAGES
- WIDESPREAD LIGHT SNOW WILL TAPER OFF THOUGH THE MORNING,
BECOMING DRY FOR MOST AFTERNOON FOR MOST.
- NORTHERLY WINDS MAY PUSH A LAKE EFFECT SNOW BAND OFF LAKE HURON
INTO THE NORTHERN AND EASTERN THUMB WHICH COULD RESULT IN SOME
ADDITIONAL SNOW ACCUMULATIONS.
- WARMING TREND WILL COMMENCE HEADING INTO THE WEEKEND WITH HIGH
TEMPERATURES BACK UP TO FREEZING BY SUNDAY, AND UP TO AROUND 40
MONDAY THROUGH WEDNESDAY.
DISCUSSION
WIDESPREAD LIGHT SNOW IS ONGOING AND WILL CONTINUE THROUGH THE
MORNING HOURS. THERE WILL BE A DECREASING TREND THROUGH THIS TIME
FROM NW TO SE AS THE UPPER LOW NOW CENTERED OVER CLE WILL CONTINUE
DRIFTING EASTWARD, PULLING THE WEAKENING DEFORMATION AXIS AWAY WHILE
ALSO DRAWING THE LAKE TROUGH SOUTHWARD AS WELL. THE RESULTING
NORTHWESTERLY FLOW WILL OFFER AN INCREASINGLY DRIER AIRMASS THROUGH
THE AFTERNOON. ANY ADDITIONAL ACCUMULATIONS THROUGH THE MORNING WILL
BE MAYBE A TENTH OR TWO, KEEPING TOTALS GENERALLY AROUND A HALF INCH.
WE DO CONTINUE TO WATCH THE EASTERN AND NORTHERN THUMB FOR THE
POTENTIAL FOR THE NORTHEASTERLY WINDS OVER THE LAKE PUSH THE LAKE
BAND TOWARDS SHORE BEFORE BACKING MORE TOWARD THE NORTHWEST, PUSHING
THE BAND BACK OVER THE LAKE. HIRES MODELS GIVE THE TYPICAL SPREAD,
VARYING FROM IT PUSHING ALL THE WAY THROUGH BAD AXE OR STAYING
OFFSHORE ALTOGETHER. LUCKILY, AS MENTIONED IN THE EVENING UPDATE,
THE CONVECTIVE DEPTH THROUGHOUT THE SOUNDINGS IS FIRMLY AROUND 5-
6KFT THANKS TO THE STOUT RIDGE ALOFT, LIMITING THE SNOWFALL
POTENTIAL WITH THIS SETUP. WILL KEEP THE ACCUMULATIONS AROUND AN
INCH FOR NOW.
HIGH PRESSURE OVER THE PLAINS WILL BUILD EASTWARD THROUGH THE REST
OF THE WEEK, EVENTUALLY ENCOMPASSING THE ENTIRE CONUS EAST OF THE
ROCKIES. 500MB HEIGHTS WILL ALSO BE INCREASING AS THE WESTERN RIDGE
GETS DRAWN INTO THE REGION IN THE WAKE OF TODAYS TROUGH. NOT THE
CLEANEST RIDGE AS A SHORTWAVE TROUGH GETS CUTOFF OVER THE FOUR
CORNERS AND SEVERAL WEAK SHORTWAVES WORK THROUGH THE NORTHWESTERLY
FLOW BUT WITH THE LACK OF A DOMINATE NORTHERN STREAM JET CHANNEL,
THE TRACKS OF ONE WAVE TO THE NEXT MAY WAVER THROUGHOUT THE BROADER,
WEAKER FLOW. LOOKS LIKE WE SHOULD REMAIN DRY WITH THE RIDGING
THROUGHOUT THE COLUMN, BUT PRECIP CHANCES RETURN SUNDAY AND THEN WE
COULD GET INTO A PROGRESSIVE PATTERN WITH A WAVE RIPPLING THROUGH
THE REGION ONCE A DAY.
PTYPE MAY BECOME A CONCERN HEADING INTO NEXT WEEK AS THE MODERATING
AIRMASS WITHIN THE AIRMASS, AND SURFACE RIDGE SHIFTING EAST ALLOWING
FOR WEST/SW FLOW TO WARM US BACK TO AROUND 40 FOR HIGHS MONDAY AND
BEYOND.
MARINE
WEAK LOW PRESSURE BRINGS RELATIVELY LIGHT WINDS AND WIDESPREAD LIGHT
SNOW THROUGH THE MORNING HOURS. AS THE SYSTEM DEPARTS THIS
AFTERNOON, NORTH TO NORTHWEST WIND WILL INCREASE TO AROUND 20 KNOTS
THROUGH TONIGHT WITH MORE LOCALIZED LAKE EFFECT SNOW SHOWERS
CONTINUING OVER LAKE HURON. HIGH PRESSURE BUILDS INTO THE MID-
MISSISSIPPI VALLEY ON FRIDAY WITH A RIDGE EXTENDING NORTHEAST INTO
THE GREAT LAKES TO MAINTAIN A PERIOD OF LIGHTER WINDS THROUGH THE
DAY. SOUTHWEST WIND THEN BEGINS TO INCREASE AGAIN FRIDAY NIGHT INTO
SATURDAY AS THE RIDGE PASSES EAST AND MILDER AIR BEGINS TO WORK IN.
WIND MAGNITUDE AGAIN LOOKS TO TOP OUT AROUND 20 TO 25 KNOTS, BUT
THERE WILL BE A CHANCE FOR SOME 30 KNOT GUSTS OVER PARTS OF LAKE
HURON SATURDAY AFTERNOON AND EVENING AS A COLD FRONT APPROACHES FROM
THE NORTH. A CLIPPER SYSTEM WILL THEN DROP INTO THE REGION SUNDAY
NIGHT INTO MONDAY BRINGING THE NEXT INCREASE IN SOUTH WINDS AHEAD OF
IT.
PREV DISCUSSION
ISSUED AT 1153 PM EST WED FEB 19 2025
AVIATION...
LIGHT SNOW IS INCREASING COVERAGE AND INTENSITY ON SCHEDULE AS
MIDWEST LOW PRESSURE SLIDES JUST SOUTH OF THE MI BORDER LATE
TONIGHT. CLOUD CEILING HOVERS AROUND THE MVFR THRESHOLD GIVEN
MAINTENANCE OF THE NW CLOUD LAYER WIND COMBINED WITH THE CENTRAL
GREAT LAKES SURFACE TROUGH. ALONG WITH THE CLOUDS, BRIEF MVFR
VISIBILITY QUICKLY DROPS INTO IFR AS SNOW SPREADS ACROSS THE
TERMINAL CORRIDOR DURING PEAK INTENSITY AND THEN BACKS OFF INTO MVFR
DURING THE MORNING. SNOW ENDS WHILE MVFR CEILING LINGERS IN A
RENEWED NW WIND FIELD THIS AFTERNOON AND THURSDAY EVENING.
FOR DTW... A PERIOD OF LIGHT SNOW AVERAGES IFR VISIBILITY DURING THE
LATE NIGHT GRADUALLY IMPROVING TO MVFR THROUGH MUCH OF THE MORNING.
PROJECTIONS ARE FOR EVENT TOTAL ACCUMULATION AROUND 0.5 INCH.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING AT OR BELOW 5000 FEET TONIGHT AND THURSDAY.
* HIGH FOR SNOW AS PRECIPITATION TYPE TONIGHT AND THURSDAY.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...DRK
MARINE.......TF
AVIATION.....BT
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