799
FXUS63 KDTX 192040
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
340 PM EST WED FEB 19 2025
KEY MESSAGES
- LIGHT SNOWFALL CHANCES TODAY ACROSS MID MICHIGAN AND INTO THE
NORTHERN THUMB. BETTER CHANCES FOR WIDESPREAD LIGHT SNOW WEDNESDAY
NIGHT 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
SNOW ACCUMULATIONS.
- TEMPERATURES OF 5 TO 10 DEGREES BELOW NORMAL WILL HOLD THROUGH THE
REMAINDER OF THE WEEK.
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.
PREV DISCUSSION
ISSUED AT 1246 PM EST WED FEB 19 2025
AVIATION...
STRATIFORM CLOUD ENSCONCED WITHIN THE LOWEST 3 KFT AGL PERSISTS
TODAY WITH SOME POCKETS OF LIGHT FLURRIES. NO VISIBILITY REDUCTIONS
HAVE BEEN NOTED WITH THESE FLURRIES, AND SHOULD CONTINUE AS SUCH.
COVERAGE OF THE MVFR CLOUD DECK COULD BECOME BROKEN MID-AFTERNOON,
BUT THE CONFIDENCE IN DIURNAL VFR HEIGHT RECOVERY HAS DECREASED,
THEREFORE THE LATEST TAFS ADVERTISE MVFR INTO UNTIL THIS EVENING.
THE EXCEPTION WOULD BE FOR DTW/DET/YIP WHICH ARE BASED SLIGHTLY
HIGHER THAN THE NORTHERN TERMINALS, THEREFORE ANY IMPROVEMENT IN
BOUNDARY LAYER DEPTHS COULD PUSH HEIGHTS JUST ABOVE THE 3 KFT MARK.
WEAK LOW-LEVEL FLOW VEERS NORTH-NORTHEASTERLY THIS EVENING WHICH
INTRODUCES SOME DRIER AIR THAT MORE LIKELY LIFTS THE STRATUS CLOSER
TO 4 KFT AGL. ANY IMPROVEMENT WOULD BE SHORT-LIVED AS THE NEXT
WINTER SYSTEM SPINS OVER THE OHIO VALLEY BRINING LOWER CEILINGS AND
THE POTENTIAL FOR MORE ROBUST SNOWFALL. PERIODS OF IFR
CEILINGS/VISIBILITIES EXPECTED, ALTHOUGH THERE HAS BEEN A SLIGHT
DECREASE IN SNOWFALL DURATION AND INTENSITY WITH THIS EVENT. WINDS
WILL GENERALLY BE LIGHT (LESS THAN 10 KNOTS) THROUGH THE PERIOD WITH
THE MVFR CEILINGS PERSISTING THROUGH MOST OF THURSDAY MORNING.
DTW THRESHOLD PROBABILITIES...
* HIGH IN CEILING AT OR BELOW 5000 FEET THROUGH THURSDAY MORNING.
* HIGH IN PRECIPITATION TYPE AS SNOW TONIGHT AND THURSDAY MORNING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...CB
MARINE.......TF
AVIATION.....KGK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page