773
FXUS63 KDTX 151753
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1253 PM EST SUN DEC 15 2024
KEY MESSAGES
- POTENTIAL FOR SLICK CONDITIONS ACROSS THE SAGINAW VALLEY THIS
MORNING AS FREEZING RAIN TRACKS THRU THE AREA. A WINTER WEATHER
ADVISORY REMAINS IN EFFECT.
- WARMER CONDITIONS TODAY AS AREAS OF LIGHT RAIN PERSIST.
- SEASONABLY WARM TEMPERATURES BREAK THE 50 DEGREE MARK (SOUTH OF I-
69) MONDAY WITH MORE RAIN, THEN READINGS DECLINE THROUGHOUT THE
WORKWEEK.
AVIATION
SCATTERED LIGHT RAIN SHOWERS/DRIZZLE WILL CONTINUE TO SPREAD ACROSS
TERMINALS, ESPECIALLY ACROSS THE SOUTHERN METRO TERMINALS, THROUGH
THE AFTERNOON. WARMING SURFACE TEMPERATURES ENSURES ALL RAIN
PRECIPITATION TYPE. ABUNDANT LOW LEVEL MOISTURE IS RESULTING IN
IFR/LIFR CEILINGS THAT WILL STICK AROUND THROUGH TONIGHT AS LIGHT
RAIN SHOWERS AND DRIZZLE CONDITIONS GRADUALLY FADE AND FOGGY
CONDITIONS BECOME THE PREVAILING WEATHER. DOWNSTREAM OBSERVATIONS
AND GUIDANCE SUPPORT IFR/LIFR VISIBILITY DEVELOPING THROUGHOUT THIS
EVENING AND HOLDING THROUGH THE BULK OF TONIGHT. MAY BEGIN TO SEE
SLIGHT IMPROVEMENTS POST 12Z TOMORROW MORNING AS FLOW BECOMES
SOUTHERLY AND DRY AIR BEGINS TO MIX IN THE LOWER LEVELS.
FOR DTW...LIGHT RAIN/DRIZZLE WILL TAPER OFF BY THIS EVENING WITH
MEDIUM CONFIDENCE THAT CEILINGS/VSBYS WILL FALL INTO VLIFR
RESTRICTIONS LATE THIS EVENING AND HOLD THROUGH THE OVERNIGHT
PERIOD.
DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILINGS AT OR BELOW 5000 FEET THROUGH MONDAY MORNING.
* HIGH IN PRECIPITATION BEING ALL RAIN THROUGH.
* MEDIUM FOR CIGS/VSBY TO FALL BELOW 200 FT AND/OR 1/2 SM TONIGHT.
PREV DISCUSSION
ISSUED AT 857 AM EST SUN DEC 15 2024
UPDATE...
THE WIDESPREAD AREA OF LIGHT RAIN IS TAPERING OFF THIS MORNING AS
PARENT ISENTROPIC ASCENT CONTINUES TO WEAKEN AND SLIDE EAST OF THE
AREA. ADDITIONAL SCATTERED SHOWERS TIED TO ARRIVAL OF THE CLOSED
UPPER LOW ARE LIFTING NORTHEAST FROM NORTHERN IN INTO SOUTHERN LOWER
MI, A TREND THAT WILL BRING THEM ACROSS SOUTHEAST MI OVER THE NEXT
SEVERAL HOURS. LATEST SURVEY OF AVAILABLE AIR, ROAD, AND SOIL
TEMPERATURE OBSERVATIONS SHOW READINGS IN THE MID TO UPPER 30S FOR
AREAS SOUTH OF I-69 AND READINGS BETWEEN 32 AND 34 TO THE NORTH.
THESE TEMPS WILL CONTINUE TO RISE THIS MORNING AS MILDER AIR WORKS
IN FROM THE SOUTH, AND DO NOT EXPECT WIDESPREAD IMPACTS FROM
FREEZING RAIN GOING FORWARD. THUS WILL ALLOW THE WINTER WEATHER
ADVISORY FOR MIDLAND, BAY, AND SAGINAW COUNTIES TO EXPIRE AT 9 AM.
SOME AREAS, ESPECIALLY RURAL LOCALES, ALONG AND NORTH OF I-69 MAY
CONTINUE TO SEE SLICK/ICY ROAD CONDITIONS FOR SEVERAL HOURS AS
SURFACE TEMPS AND DEW POINTS SIT TENUOUSLY CLOSE TO THE FREEZING
MARK, BUT COVERAGE OF PRECIP WILL BE LOW UNTIL THE SHOWERS ARRIVE
FROM THE SOUTH MAINLY TOWARD NOON.
PREV DISCUSSION...
ISSUED AT 351 AM EST SUN DEC 15 2024
DISCUSSION...
EARLY MORNING SURFACE ANALYSIS SHOWS LOW PRESSURE TRACKING ACROSS
WESTERN ILLINOIS, WITH A WARM FRONTAL ZONE STRETCHING EASTWARD INTO
OHIO VALLEY. CORRIDOR OF MOIST ISENTROPIC ASCENT EMANATING NORTH OF
THESE FEATURES MAINTAINED WITHIN THE BROADER REGION OF ELEVATED WARM
AIR ADVECTION, RESULTING IN AN EXPANSIVE PRECIPITATION SHIELD NOW
MAKING INROADS THROUGHOUT SOUTHEAST MICHIGAN. DRY EASTERLY FLOW
EFFECTIVELY RELENTING FROM SOUTH TO NORTH AS SUFFICIENT MAGNITUDE TO
THETA-E ADVECTION WORKS TO SATURATE THE PROFILE, WHILE A WARMING
COLUMN ENSURES THIS ARRIVES IN LIQUID FORM. PERUSAL OF LOCAL
OBSERVATIONS SUGGEST ADEQUATE NEAR SURFACE WARMING NOW ALLOWING
TEMPERATURES FOR MOST LOCATIONS OUTSIDE OF THE SAGINAW VALLEY TO
RESIDE SAFELY ABOVE FREEZING, MEANING SIMPLY JUST RAIN GOING
FORWARD. WINDOW REMAINS ACROSS THE SAGINAW VALLEY FOR FREEZING RAIN
TO GENERATE SOME LIGHT ICE ACCUMULATION OVER THE NEXT SEVERAL HOURS.
WINTER WEATHER ADVISORY REMAINS IN EFFECT THROUGH 12Z FOR THIS
CORRIDOR.
MOIST AND MILDER CONDITIONS WILL EXIST THROUGHOUT SUNDAY AS THE
TRAILING CLOSED LOW MEANDERS ACROSS THE REGION ATOP AN INCREASINGLY
DIFFUSE WARM FRONT/TROUGH AXIS. THIS PATTERN MAINTAINS UNSETTLED
CONDITIONS AS FOCUSED AREAS OF DCVA WITHIN THE UNDERLYING MID LEVEL
CYCLONIC FLOW CONTRIBUTES ADDITIONAL POCKETS OF LIGHT RAIN/DRIZZLE
DURING THE DAYLIGHT HOURS. THE MODERATING THERMAL PROFILE WILL
SUPPORT HIGHS NEAR 40 DEGREES. A QUICK TRANSITION TOWARD BUILDING
UPPER HEIGHTS TONIGHT WITH THE BACKGROUND OF SOUTH TO SOUTHEAST LOW
LEVEL WILL MINIMIZE ANY NOCTURNAL COOLING POTENTIAL, LEAVING LOWS
WITHIN SEVERAL DEGREES OF LATE DAY READINGS.
WARMING TREND SOLIDIFIED HEADING INTO MONDAY AS FLOW VEERS TO
SOUTHWESTERLY AND INCREASES DEPTH IMMEDIATELY DOWNSTREAM OF THE NEXT
INBOUND UPPER WAVE. ANOTHER QUICK SHOT OF MEANINGFUL MOIST
ISENTROPIC ASCENT WITHIN THE STRENGTHENING PATTERN OF WARM AIR
ADVECTION RESULTS IN A HIGH PROBABILITY, LIGHT RAINFALL EVENT DURING
THE DAYLIGHT PERIOD. COLLECTIVE ENSEMBLE SOLUTION SPACE ONBOARD WITH
THIS OUTCOME. TEMPERATURES PEAK THIS PERIOD NEAR 50 DEGREES. MODEST
COLD AIR ADVECTION EMERGES MONDAY EVENING INTO THE OVERNIGHT HOURS
AS HEIGHT FALLS COMMENCE WITH THE UPPER TROUGH PASSAGE. THE
ADVECTIVE PROCESS LACKS STRENGTH GIVEN PACIFIC ORIGIN, BUT MAY
CONTRIBUTE TO SOME GUSTINESS OF WEST-SOUTHWEST WIND OVERNIGHT WITHIN
THE POST-FRONTAL ENVIRONMENT AS PROJECTED WINDS OF 30-35 KNOTS EXIST
AT THE TOP OF THE MIXED LAYER.
A MILDER RESIDENT THERMAL PROFILE WILL HOLD INTO THE MIDWEEK PERIOD,
AS THE LARGE SCALE PATTERN REMAINS GOVERNED BY LOWER AMPLITUDE FLOW
OF POLAR ORIGIN. DRY AND GUSTY CONDITIONS PERSIST INTO TUESDAY
WITHIN A FIRM WESTERLY GRADIENT. A BRIEF PERIOD OF MEANINGFUL FORCED
ASCENT WILL ATTEMPT TO MATERIALIZE WEDNESDAY WITHIN THE NORTH FLANK
OF LOW PRESSURE TRACKING ACROSS THE OHIO/TENNESSEE VALLEY AND ALONG
A COLD FRONT ATTENDANT TO ADDITIONAL INBOUND HEIGHT FALLS FROM THE
NORTH. AN ILL-DEFINED SETUP AT THIS STAGE OWING TO EXPECTED
DEVIATION WITHIN THE MODEL SOLUTION SPACE ON PLACEMENT AND
INTERACTION OF KEY FEATURES. FORECAST WILL CONTINUE TO OFFER A MORE
GENERAL OUTLOOK FOR THE POSSIBILITY OF LIGHT RAIN AND SNOW GIVEN
MARGINAL MELTING LAYER DEPTH FOCUSED DURING THE DAYLIGHT PERIOD
WHERE TEMPS PEAK IN THE MID/UPPER 30S.
MARINE...
SOUTHEAST WINDS OF 15 TO 25 KNOTS CONTINUE OVER LAKE HURON TODAY,
ALLOWING 4+ WAVES TO IMPACT THE NEARSHORE ZONES. WINDS ATTEMPTING TO
BECOME MORE DUE SOUTHERLY INTO SUNDAY NIGHT. WARMER AIR WILL
GRADUALLY WORK INTO THE REGION ALLOWING FOR PRECIPITATION TO FALL
FALL AS RAIN TODAY AS WEAKENING LOW PRESSURE TRACKS IN FROM THE
MIDWEST. THIS LOW AND ANY COLD AIR FIZZLE OUT IN FAVOR OF THE
STRONGER/MORE AMPLIFIED UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS
SUNDAY NIGHT.
RESUMED MODERATE SOUTHERLY FLOW CAN BE EXPECTED WITH ADDITIONAL RAIN
BY MONDAY. COLD FRONT, ATTACHED TO LOW PRESSURE TRACKING THROUGH
ONTARIO AND NEAR JAMES BAY, WILL SWING THROUGH THE CENTRAL GREAT
LAKES EARLY MONDAY EVENING. TIGHT PRESSURE GRADIENT WITH 850 MB
TEMPS LOWERING TO AROUND -8 C LOOKS SUPPORTIVE OF WIND GUSTS IN
THE 30 TO 35 KNOT RANGE OVER CENTRAL AND NORTHERN LAKE HURON, LATE
MONDAY NIGHT INTO EARLY TUESDAY MORNING. HOWEVER, GUSTS TO GALES
APPEAR TO BE BRIEF, AS THE PRESSURE GRADIENT QUICKLY RELAXES DURING
THE DAY ON TUESDAY. THUS, NOT PLANNING ON GALE WATCH AT THIS TIME.
AN EVEN STRONGER COLD FRONT LOOKS TO BE MOVING THROUGH ON WEDNESDAY,
AND NORTHERLY WINDS LATE WEDNESDAY THROUGH THURSDAY MORNING WILL
LIKELY REACH INTO THE 20 TO 30 KNOT RANGE, BUT ULTIMATELY INFLUENCED
BY THE STRENGTH AND POSITION OF LOW PRESSURE TRACKING THROUGH/NEAR
THE SOUTHERN OHIO VALLEY. A RIDGE OF HIGH PRESSURE QUICKLY FOLLOWS,
ALLOWING FOR A PERIOD OF LIGHT WINDS TO END THE WORK WEEK.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LHZ441-442.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LHZ443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....AA
UPDATE.......TF
DISCUSSION...MR
MARINE.......SF
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