675
FXUS63 KDTX 192357
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
657 PM EST WED FEB 19 2025
KEY MESSAGES
- WIDESPREAD LIGHT SNOW DEVELOPS TONIGHT INTO THURSDAY MORNING AS A
SYSTEM PASSES TO OUR SOUTH BUT REACHES UP INTO MICHIGAN. GENERALLY
AROUND A HALF INCH OF SNOW IS EXPECTED.
- NORTHERLY WINDS THURSDAY MAY PUSH A LAKE EFFECT SNOW BAND OFF LAKE
HURON INTO THE NORTHERN AND EASTERN THUMB WHICH COULD RESULT IN
SOME ADDITIONAL SNOW ACCUMULATIONS.
- TEMPERATURES OF 5 TO 10 DEGREES BELOW NORMAL WILL HOLD THROUGH THE
REMAINDER OF THE WEEK.
AVIATION
MIDWEST LOW PRESSURE BRINGS A PERIOD OF LIGHT SNOW WHILE SLIDING
JUST SOUTH OF THE MI BORDER TONIGHT. EXISTING STRATOCU 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, VISIBILITY DROPS INTO MVFR WITH A FEW HOURS OF IFR AS SNOW
SPREADS ACROSS THE TERMINAL CORRIDOR AFTER MIDNIGHT LASTING THROUGH
THE MORNING. SNOW ENDS WHILE MVFR CEILING LINGERS IN A RENEWED NW
WIND FIELD THURSDAY AFTERNOON AND EVENING.
FOR DTW... BORDERLINE MVFR/VFR CEILING LEADS INTO A PERIOD OF LIGHT
SNOW LATE TONIGHT, BEGINNING AFTER MIDNIGHT AND LASTING 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.
PREV DISCUSSION
ISSUED AT 340 PM EST WED FEB 19 2025
DISCUSSION...
A LOBE OF PLANETARY VORTICITY AND A MYRIAD OF FAIRLY DISORGANIZED
SHORTWAVE ENERGY WILL STEADILY COALESCE WHILE PIVOTING THROUGH THE
UPPER MISSISSIPPI RIVER VALLEY AND CENTRAL GREAT LAKES THIS
AFTERNOON AND TONIGHT. H5 GEOPOTENTIAL CHARTS AND ABSOLUTE VORTICITY
FIELDS SUPPORT AMPLIFICATION AND MIDLEVEL LOW PRESSURE DEEPENING
THROUGH PORTIONS OF NORTHERN IN/OH BETWEEN 00-06Z TONIGHT. ALL
INDICATIONS ARE THAT WEAK AGEOSTROPHIC OR DEFORMATION RESPONSE OF
THE DEVELOPING LOW WILL PASS IMMEDIATELY SOUTH OF THE MICHIGAN BORDER
, HOWEVER, MODELS HAVE BEEN VERY CONSISTENT IN ADVECTING REMNANT
ATLANTIC MOISTURE SOUTHWARD INTO LOWER MICHIGAN FROM ONTARIO.
FORECAST 290-280KT SURFACES SIGNAL SHALLOWLY SLOPED ISENTROPIC
ASCENT BETWEEN 05-12Z WITH A MATCH IN TIMING TO DEEP SATURATION IN
THE FORECAST SOUNDINGS. SOUNDINGS SHOW DEEP MOISTURE WITH AT LEAST
A BOUNDARY LAYER CONNECTION INTO THE DENDRITIC GROWTH ZONE INTO THE
DAYLIGHT THURSDAY. MUCH OF THE DETERMINISTIC AND ENSEMBLE GUIDANCE
REMAINS LEAN ON QPF, BUT GIVEN THE SETUP QUALITATIVELY PREFERENCE IS
TO CARRY A HIGH POP (APPROXIMATELY 60%) WITH LOW QPF (SNOW
ACCUMULATION OF DUSTING OR A COUPLE OF TENTHS). GIVEN THE COLD
TEMPERATURES AND REFRIGERATED GROUND, SUSPECT THAT FLURRIES AND LIGHT
SNOW ACTIVITY WILL BE ABLE TO ACCUMULATE EFFICIENTLY FOR A LIGHT
ACCUMULATION. COLD NORTHERLY FLOW WITH SOME CYCLONIC VORTICITY
DIFFERENTIAL 1000-500MB GEOPOTENTIAL HEIGHT RISES WILL SUPPORT
SURFACE HIGH PRESSURE BUILDING THROUGH THE GREAT LAKES LATE THURSDAY
THROUGH EARLY SUNDAY. QUIET WEATHER WITH HIGH CONFIDENCE IN STRONG
STATIC STABILITY BETWEEN 4.0 AND 9.0 FT AGL. DAYTIME TEMPERATURES
WILL RANGE IN THE UPPER 20S FRIDAY AND SATURDAY, SOME 5 TO 10
DEGREES BELOW NORMAL.
VERY DISORGANIZED SHORTWAVE ENERGY IS FORECASTED TO ADVECT ALONG IN
THE WEST TO NORTHWEST FLOW THIS WEEKEND AND EARLY NEXT WEEK. PLENTY
OF OPPORTUNITY EXISTS FOR PERIODIC CHANCES AT FLURRIES, BUT WARM AIR
IS FORECASTED TO REMAIN IN PLACE DIFFERENTIALLY ALOFT. THE ONE TIME
PERIOD TO MONITOR MAY BE ON MONDAY AS THE EXIT REGION OF THE NEXT
UPPER LEVEL JET STREAK COULD ARRIVE. THE CURRENT FORECAST HAS A LOW
CHANCE FOR A RAIN/SNOW MIX WITH PACIFIC AIR MASS ALLOWING FOR
TEMPERATURES OF NEAR 40 DEGREES.
MARINE...
A WEAK SURFACE TROUGH HOLDS OVER THE CENTRAL GREAT LAKES THROUGH
THIS EVENING WITH JUST ENOUGH CONVERGENCE WITHIN THE WEAK N TO NW
FLOW TO MAINTAIN SOME POCKETS OF SNOW SHOWERS OVER LAKE HURON. AN
UPPER LEVEL DISTURBANCE PASSING OVER TONIGHT WILL THEN BRING A MORE
WIDESPREAD AREA OF LIGHT SNOW FROM LATE THIS EVENING INTO THURSDAY.
AN UPTICK IN N TO NW WIND ENSUES THURSDAY AFTERNOON INTO THURSDAY
NIGHT AS THIS SYSTEM PASSES, TOPPING OUT AROUND 20 TO 25 KNOTS. HIGH
PRESSURE BUILDS INTO THE MID-MISSISSIPPI VALLEY ON FRIDAY, EXTENDING
NORTHEAST INTO THE GREAT LAKES. THIS MAINTAINS LIGHTER WIND THAT
SHIFTS SW AND BEGINS TO INCREASE AGAIN FRIDAY NIGHT INTO SATURDAY.
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 INTO
MONDAY BRINGING THE NEXT INCREASE IN SOUTH WINDS AHEAD OF IT.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....BT
DISCUSSION...CB
MARINE.......TF
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