808
FXUS63 KDTX 142342
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
642 PM EST TUE JAN 14 2025
KEY MESSAGES
- LIGHT SNOW IS LIKELY BETWEEN 5AM AND 11AM THURSDAY.
- THERE IS A 50 PERCENT CHANCE OF PRECIPITATION ON SATURDAY.
PRECIPITATION TYPE AND AMOUNTS CARRY A GOOD DEAL OF UNCERTAINTY AT
THIS STAGE IN THE FORECAST.
- SUB ZERO WIND CHILLS ARE FORECAST EARLY NEXT WEEK. THIS WILL BE
THE COLDEST AIRMASS TO AFFECT THE AREA SO FAR THIS SEASON.
AVIATION
PERIOD OF CLEAR SKY EXISTS EARLY TONIGHT, AS A BRIEF WINDOW OF DRY
LOW LEVEL NORTHWEST FLOW MAINTAINS CONTROL. GRADUAL VEERING OF LOW
LEVEL FLOW WITH TIME OVERNIGHT AND EARLY WEDNESDAY WILL DRAW LAKE
MOISTURE BACK INTO THE REGION. THIS WILL SUPPORT AN INCREASE IN
CLOUD COVERAGE DURING THIS TIME. CLOUD BASE INITIALLY AT LOWER VFR,
BUT SOME REDUCTION TO NEAR MVFR REMAINS PLAUSIBLE BY WEDNESDAY
MORNING AS WARMING ATOP THE INVERSION BEGINS TO LOWER THE INVERSION
BASE. BROKEN COVERAGE OF STRATUS LIKELY TO LINGER INTO THE
AFTERNOON, BEFORE THE MODEST WARMING AS LOW LEVEL WINDS SETTLE TO
SOUTHWEST FAVOR A CLEARING TREND TOWARD WEDNESDAY EVENING.
DTW THRESHOLD PROBABILITIES...
* LOW FOR CIGS AOB 5000 FEET TONIGHT. MEDIUM WEDNESDAY.
PREV DISCUSSION
ISSUED AT 258 PM EST TUE JAN 14 2025
VISIBLE IMAGERY THIS AFTERNOON HIGHLIGHTS THAT A GOOD AMOUNT OF
SUNSHINE HAS BROKEN OUT IN THE SUBSIDENCE REGION BEHIND THE
DEPARTING SHORTWAVE. WILL LIKELY OBSERVE VARYING AMOUNT OF CLOUDS
THROUGHOUT THE REMAINDER OF THE DAYLIGHT HOURS. WEST FLOW TONIGHT
WITH NOCTURNAL COOLING IS EXPECTED TO RESULT IN ENOUGH SATURATION
FOR STRATOCUMULUS DEVELOPMENT. SUPERSATURATION WITH RESPECT TO ICE
WITHIN THE CLOUD BEARING LAYER AT -10 TO -11C WILL LIKELY SUPPORT
SOME UBIQUITOUS FLURRIES. CLOUDS ARE EXPECTED TO BEGIN THE DAY
WEDNESDAY BEFORE WARM ADVECTION SCOURS OUT THE MOISTURE. PROBABLY
WILL SET SOME EARLY EVENING MINIMUMS WEDNESDAY EVENING BEFORE
SOUTHWEST WINDS INCREASE.
EXIT REGION TO UPPER LEVEL JET IMPULSE NOW AT SUPERGEOSTROPHIC
POSITION OF WESTERN NORTH AMERICA RIDGE WILL DIG INTO THE GREAT
LAKES LATE WEDNESDAY AND EARLY THURSDAY. MODELS SHOW INCREASING
CYCLONIC CURVATURE TO THE COMPOSITE TROUGH AXIS WHICH IS EXPECTED TO
RESULT IN A CORRIDOR OF LOW-MIDLEVEL CONVERGENCE HERE ACROSS LOWER
MICHIGAN. PROBLEMS WITH THE SETUP OVERALL INCLUDE, EXTREMELY QUICK
MOVEMENT OF THE SYNOPTIC CONVERGENCE, LITTLE TO NO PRECEDING
ISENTROPIC ASCENT, AND WARM THETAE/MOISTURE LAGGING THE FORCING.
BEST FRONTAL FORCING WILL BE CENTERED AROUND 700MB ASSOCIATED WITH A
LOW PRESSURE CIRCULATION AT 12Z. GOOD SATURATION THROUGH THE DGZ
OCCURS FOR A TIME, BUT DRY AIR PUSHES DOWNWARD IN THE COLUMN TO
AROUND 4.5 KFT AGL IN THE SUBSIDENCE WAKE. COLLECTION OF EPS AND
HIRESOLUTION NWP SUGGESTS A 10-16Z TIME WINDOW ON THURSDAY FOR LIGHT
SNOW. WILL ATTEMPT AT TIGHTENING THE TIME MENTION IN THE GRIDS AND
INCREASE POPS INTO THE LIKELY CATEGORY. LACK OF DURATION TO DEEPER
MOISTURE LIMITS SNOW AMOUNTS TO AN INCH OR LESS.
SPLIT UPPER LEVEL FLOW WITH RISING GEOPOTENTIAL HEIGHTS WILL GOVERN
THE WEATHER LATE THURSDAY AND FRIDAY. FORECAST SOUNDINGS SUPPORT
QUIET WEATHER WITH STRONG STATIC STABILITY BETWEEN 1.5 AND 8.0 KFT
AGL. RELATIVELY COMFORTABLE DAYTIME CONDITIONS WITH TEMPERATURES IN
THE LOWER TO MIDDLE 30S.
PHASING OF THE NORTHERN AND SOUTHERN STREAM WILL HAVE THE POTENTIAL
TO DIRECT AN AREAS OF FRONTOGENESIS ACROSS LOWER MICHIGAN ON
SATURDAY. OVERALL PREDICTABILITY OF THE EVENT APPEARS TO BE
DEPENDENT ON TIMING/DETAILS HOW SOUTHERN STREAM SHORTWAVE ENERGY
EJECTS OUT OF TEXAS AHEAD OF THE NORTHERN STREAM POTENTIAL VORTICITY
TROUGH. GUIDANCE HAS NOT BECOME SETTLED ENOUGH TO OFFER MUCH
COMMENTARY. EPS/GEPS/GEFS CLUSTER ANALYSIS SHOWS AS MANY AS 6
DIFFERENT SOLUTION CLUSTERS ALTHOUGH ITS INTERESTING TO NOTE THAT
MOST OF THE CLUSTERS DO OFFER SOME PRECIPITATION AMOUNTS. 00Z EPS
DATA IS SHOWING APPROXIMATELY 30 PERCENT OF THE SOLUTIONS AT LESS
THAN 1.0 INCH AT DTW. A PERIOD TO MONITOR.
THE BIG STORY OF THE EXTENDED IS THE COLD AIR MASS THAT WILL LIKELY
BE IN RESIDENCE DURING THE EARLY PORTION OF NEXT WEEK. LATEST EPS
DATA EXEMPLIFIES A REMARKABLY LOWER AMOUNT OF VARIANCE FOR DAYTIME
HIGHS MONDAY AND TUESDAY. MEAN VALUES SUGGEST DAYTIME HIGHS IN THE
SINGLE DIGITS ABOVE ZERO, SOME 20 TO 25 DEGREES BELOW AVERAGE.
MARINE...
A RIDGE OF HIGH PRESSURE WILL BRIEFLY FILL IN OVER THE GREAT LAKES
LATE TONIGHT AND INTO TOMORROW WHICH WILL MODERATE WIND SPEEDS AND
GUST POTENTIAL THROUGH TOMORROW MORNING. A SOUTHERN EXTENSION OF A
CLIPPER SYSTEM WILL THEN MOVE THROUGH THE NORTHERN GREAT LAKES LATE
TOMORROW NIGHT INTO THURSDAY MORNING. EXPANSION OF THIS SYSTEM INTO
THE REGION WILL BACK WIND DIRECTION TO THE SOUTHWEST. THE FAVORABLE
FETCH WILL AGAIN PROVIDE A WINDOW FOR ELEVATED WIND SPEEDS AND GUST
POTENTIAL, ESPECIALLY THROUGH THE SAGINAW BAY AND INTO CENTRAL LAKE
HURON, WHERE SUSTAINED WINDS OF 20 TO 25 KNOTS, GUSTS UP TO 30
KNOTS, WILL BE LIKELY. THIS SYSTEM ALSO BRING WIDESPREAD LIGHT SNOW
TO ALL OF THE GREAT LAKES. PASSAGE OF THE CLIPPER VEERS WIND
DIRECTION BACK TO THE NORTHWEST ON THURSDAY.
PREV DISCUSSION...
ISSUED AT 254 PM EST TUE JAN 14 2025
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....MR
DISCUSSION...CB
MARINE.......AM
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