549
FXUS63 KDTX 191204
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
704 AM 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.
AVIATION
MVFR CEILINGS ARE ENCROACHING INTO SOUTHEAST MICHIGAN THIS MORNING
AS LAKE CLOUDS REMAIN TRAPPED UNDER A SUBSIDENCE INVERSION. BOUNDARY
LAYER GROWTH INTO THE AFTERNOON SHOULD HELP LIFT THESE CEILINGS BACK
INTO LOWER END VFR, BUT IT MAY BE POSSIBLE FOR SOME SCATTERED MVFR
CEILINGS TO HOLD ON. A FEW LIGHT SNOW SHOWERS WILL BE POSSIBLE
TOWARDS MBS THIS AFTERNOON BEFORE WIDESPREAD LIGHT SNOWFALL ARRIVES
TONIGHT. LIGHT SHOWERS LIKELY TO BRING A RETURN TO WIDESPREAD MVFR
CONDITIONS. WINDS OF 5-10 KNOTS WILL HOLD GENERALLY OUT OF THE W-NW
THROUGH BULK OF THE TAF PERIOD.
FOR DTW... CLOUD BASES BELOW 5,000 FEET THROUGH THE TAF PERIOD WITH
A CHANCE FOR LIGHT SNOW TONIGHT INTO TOMORROW MORNING. ACCUMULATION
TO AROUND A HALF INCH BY TOMORROW MORNING.
DTW THRESHOLD PROBABILITIES
* MODERATE FOR CEILING AOB 5000 FEET TODAY AND HIGH TONIGHT.
PREV DISCUSSION
ISSUED AT 322 AM EST WED FEB 19 2025
DISCUSSION...
A STRONG 1050MB SURFACE CENTERED OVER SOUTHERN SASKATCHEWAN WILL
DRIFT DOWN THROUGH THE PLAINS WEDNESDAY AND THURSDAY BEFORE
SPREADING EASTWARD TO ENCOMPASS ALL OF THE CONUS EAST OF THE
ROCKIES. THIS WILL HELP GUIDE THE FORECAST FOR THE NEXT SEVERAL DAYS
AS WE THIS WEAKENING HIGH AND MODERATING AIRMASS RESIDES OVER THE
AREA.
FOR TODAY WE HAVE CONTINUED NORTHERLY FLOW WITH THE HIGH WELL TO OUR
WEST, SETTING UP THE FAVORED REGIONS FOR LAKE EFFECT ACROSS THE
GREAT LAKES. THIS TYPICALLY DOESN'T AFFECT SE MI BUT WE DO HAVE A
LAKE AGGREGATE TROUGH DRAPED ACROSS THE NORTHERN LAKES, REMAINS OF
THE LOW NOW OVER FAR EASTERN CANADA, WHICH WILL GET DISLODGED AND
FORCED SOUTHWARD TODAY AS A MID LEVEL WAVE DROPS INTO THE BROADER
TROUGH AND THEN THROUGH THE OHIO VALLEY. AS THIS TROUGH DROP SOUTH
IT WILL FOCUS THE MOISTURE AND LOW LEVEL CONVERGENCE FROM THE
VARIOUS LAKE BANDS/PLUMES ACROSS LOWER MI. THIS SHOULD BE GOOD
ENOUGH TO PRODUCE AT LEAST FLURRIES IF NOT LIGHT SNOW ACROSS MID MI
AND THE THUMB THIS AFTERNOON AS THE TROUGH REACHES THOSE AREAS. THE
NAM, RAP, AND RGEM ALL SUPPORT SOME LOW LEVEL CONVERGENCE BANDING
BENEATH THE INVERSION AROUND 6KFT THIS AFTERNOON. PLUS THAT AIRMASS
ALREADY HAS FLAKES IN IT SO THE EXTRA FOCUS SHOULD BE SEEN IN THAT
AREA. FARTHER SOUTH THE EXPECTATION IS FOR THE DRY BL AIR TO HOLD
THROUGH THE DAY. NOT TO SAY WE CAN'T GET SOME FLURRIES LATER, BUT
THERE IS MORE SUPPORT TO THE NORTH. REGARDLESS, TRACE AMOUNTS TO A
DUSTING ARE EXPECTED.
HEADING INTO TONIGHT, THE MID LEVEL LOW WILL SKIRT BY WITH THE
NORTHERN PERIPHERY REACHING UP INTO MI. WEAK ISENTROPIC ASCENT WITH
A BAND OF EPV AND WEAK DEFORMATION LOOKS TO BE ENOUGH TO SPREAD A
BROADER COVERAGE OF LIGHT SNOW ACROSS SOUTHERN MI, FOCUSED IN THE 09-
15Z THURSDAY MORNING WINDOW. THIS IS ALL WHILE THE STRONGER FORCING
FROM THE LAKE TROUGH STILL RESIDES OVER THE AREA. WE HAVE LIKELY
POPS GOING FOR THE BULK OF THIS TIME WINDOW WHICH SEEM ON TRACK AT
THIS TIME. OVERALL IT WILL BE A HIGHER POPS, LOWER QPF SYSTEM AS
MOISTURE QUALITY IS NOT THERE, WITH MODELS ONLY GENERATING A FEW
HUNDRETHS. FORECAST IS FOR AROUND A HALF INCH OF SNOWFALL. ONE THING
TO WATCH THURSDAY WILL BE THE ENHANCED NORTHERLY FLOW BEHIND THE
LAKE TROUGH, WHICH HIRES MODELS ARE SHOWING TO BE SUFFICIENT TO
PUSH THE DOMINATE (WHATS LEFT OF IT) LAKE BAND INTO THE THUMB. SO
WILL HIGHLIGHT HIGHER POPS FOR THE NORTHERN AND EASTERN THUMB FOR
SOME ADDITIONAL LAKE EFFECT.
SURFACE HIGH HOLDS FRIDAY INTO THE WEEKEND WITH WINDS TURNING MORE
WESTERLY ALLOWING FOR A WARMING TREND THROUGH THE FORECAST WITH
HIGHS REACHING THE 30S BY SUNDAY AND EVEN INTO THE 40S NEXT WEEK.
THERE ARE A COUPLE WEAK WAVES SEEN IN THE LONGER RANGE MODELS IN THE
W-NW FLOW THIS WEEKEND INTO NEXT WEEK AS WELL BUT WE'LL SEE HOW THEY
INTERACT WITH THE RIDGE AS THEY RACE THROUGH THE NORTHERN GREAT
LAKES.
MARINE...
WEAK/ILL-DEFINED PRESSURE PATTERN IN PLACE TODAY WILL RESULT IN
PREDOMINATELY LIGHT WINDS, AT OR BELOW 15 KNOTS.
HIGH PRESSURE TRACKING SOUTH THROUGH THE PLAINS WEDNESDAY NIGHT AND
THURSDAY, COUPLED WITH DEEPENING LOW PRESSURE OFF THE EAST COAST
WILL RESULT IN INCREASING NORTHERLY WINDS OVER THE CENTRAL GREAT
LAKES REGION FOR THE THURSDAY-THURSDAY NIGHT, BUT LIKELY ONLY
TOPPING OUT IN THE 20-25 KNOT RANGE PER LOCAL PROBABILISTIC
GUIDANCE.
RIDGE OF HIGH PRESSURE SLIDES THROUGH ON FRIDAY, ALLOWING FOR AT
LEAST MODERATE RETURN SOUTHWEST FLOW TO DEVELOP FRIDAY EVENING-
SATURDAY. AIRMASS STILL LOOKS TO BE COLD ENOUGH TO SUPPORT NEAR LAKE
SURFACE UNSTABLE PROFILES, AND GUSTS OF 25 TO 30 KNOTS SEEM DOABLE,
PARTICULARLY FOR CENTRAL SECTIONS OF LAKE HURON.
LOW PRESSURE LOOKS TO BE TRACKING THROUGH THE GREAT LAKES REGION
SUNDAY-MONDAY, BUT BIG DIFFERENCES AMONGST THE MODELS WITH RESPECT
TO STRENGTH AND LOCATION. EVEN IF THE STRONGER SOLUTION VERIFIES,
ANY GALE FORCE WINDS LOOK TO BE SHORT LIVED AS THE LOW LOOKS TO BE
MOVING THROUGH RATHER QUICKLY.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....AA
DISCUSSION...DRK
MARINE.......SF
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