590
FXUS63 KDTX 190454
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EST SAT JAN 18 2025
KEY MESSAGES
- COLD AIR ADVECTION IS ONGOING IN THE WAKE OF THE MORNING COLD
FRONT. TEMPERATURES WILL CONTINUE TO DECREASE THROUGH THE AFTERNOON
REACHING THE LOW TEENS LATER TONIGHT.
- THE COLDEST TEMPERATURES OF THE WINTER THUS FAR ARRIVE EARLY NEXT
WEEK. DANGEROUS WIND CHILLS OF -15 TO -25 LIKELY FOR THE MORNING
HOURS, WITH LITTLE RELIEF FOR THE AFTERNOON, CENTERED MONDAY THROUGH
WEDNESDAY.
AVIATION
INTERVALS OF LOWER VFR LAKE STRATUS WILL CONTINUE TO FUNNEL ACROSS
SOUTHEAST MICHIGAN DURING THE EARLY-MID MORNING HOURS. THIS MOISTURE
TIED TO ONGOING NORTHWEST FLOW OF MODEST WIND SPEED. APPROACHING MID
LEVEL WAVE WILL LIKELY MAINTAIN A HIGHER COVERAGE OF VFR CLOUD
HEADING INTO SUNDAY. THIS WAVE MAY ALSO LEAD TO AN UPTICK IN
COVERAGE OF LIGHT SNOW SHOWERS SUNDAY AFTERNOON AND EVENING,
PARTICULARLY ACROSS THE DETROIT AIRSPACE UP THROUGH PTK.
DTW THRESHOLD PROBABILITIES...
* LOW FOR CEILING AOB 5000 FEET TONIGHT. MEDIUM SUNDAY.
* HIGH FOR PTYPE OF SNOW FOR ANY LIGHT ACTIVITY SUNDAY INTO SUNDAY
NIGHT.
PREV DISCUSSION
ISSUED AT 348 PM EST SAT JAN 18 2025
DISCUSSION...
THE ARCTIC FRONT IS NOW TO OUR EAST AND WE WILL BE TURNING ATTENTION
TOWARD THE WELL ADVERTISED ARCTIC AIR OUTBREAK THAT WILL CARRY
THROUGH MID WEEK. IN ADDITION, THIS COLD AIRMASS OVER THE OPEN LAKES
WILL EXCITE MORE LAKE EFFECT SNOW SHOWERS THROUGH THE FIRST HALF OF
THE WEEK. BIGGER IMPACT FROM THE LIGHT ACCUMULATIONS WE COULD SEE
MAY END UP BEING THE RESULTANT CLOUD COVER AND ITS IMPACT ON THE LOW
TEMPERATURES. MORE ON THIS BELOW.
THE ARCTIC OUTBREAK IS NOW UNDERWAY WITH COLD AIR ADVECTION OCCURING
ACROSS THE REGION IN THE WAKE OF THE MORNING COLD FRONT. AFTER
STARTING OFF THE DAY WITH TEMPS IN THE MID/UPPER 30S, MOST OF THE
AREA IS NOW DOWN INTO THE MID/UPPER 20S ALREADY AND WILL BE DOWN
INTO THE LOW TEENS TONIGHT. LOOKING AT 850MB TEMPS TRENDS, WE'RE
EXPECTING THEM TO FALL TO -10C OR LESS BY 00Z TONIGHT AND -15 TO -
20C BY 12Z SUNDAY MORNING. A MID LEVEL TROUGH WILL SWING THROUGH
SUNDAY NIGHT OPENING THE DOOR FOR EVEN COLDER AIR DOWN TO AROUND -25C
TO SLIDE INTO THE REGION. SO AFTER STARTING THE MORNING OFF IN THE
LOW SINGLE DIGITS, THERE WILL NOT BE MUCH RELIEF AS HIGHS STAY
MOSTLY BELOW 10F OUTSIDE OF THE DETROIT METRO AREA. EVEN SO, THE
COLDEST AIR IN THE POLAR VORTEX STILL RESIDES TO THE WEST OVER MN/WI
AND WON'T ARRIVE UNTIL TUESDAY WHEN THE NEXT TROUGH AXIS PASSES OVER
THE GREAT LAKES. THIS IS WHERE 850MB TEMPS WILL BOTTOM OUT AROUND -
25C TO -30C DEPENDING ON THE AMOUNT OF AIRMASS MODIFICATION THAT
OCCURS AS IT PASSES OVER THE LAKES. LOWS MONDAY NIGHT SHOULD FALL TO
AROUND 0 TO -5F WHICH IS SLIGHTLY WARMER THAN PREVIOUS FORECAST BUT
THIS COULD BE DUE TO MID RANGE MODELS PICKING UP ON THE LAKE EFFECT
CLOUDS/SNOW SIGNAL AND MORE CLOUDS MEANS WARMER LOWS. SO ADJUSTMENTS
WILL BE LIKELY IN THIS WINDOW. TUESDAY NIGHT SHOULD BE THE COLDEST
NIGHT WHEN LOWS FALL SOLIDLY INTO THE NEGATIVE SINGLE DIGITS
ACROSS THE REGION. COLDEST CORE OF AIR THEN PUSHES OFF TO THE
NORTHEAST TUESDAY NIGHT INTO WEDNESDAY WITH TEMPS TRENDING WARMER
BACK TO NEAR AVERAGE FOR THE END OF THE WEEK.
THE VERY COLD AIRMASS WILL BRING ADDED CONCERNS WITH WIND CHILLS
WHICH WILL FALL BELOW ZERO SUNDAY NIGHT AND LIKELY REMAIN IN THE
NEGATIVES UNTIL THURSDAY MORNING. THE LOWEST VALUES FORECAST ARE
STILL IN THE -10 TO -15F RANGE WHICH HAS BEEN FAIRLY CONSISTENT THE
LAST FEW DAYS. AS THIS FALLS BELOW THE -25F THRESHOLD FOR A EXTREME
COLD WATCH/WARNING, WE'LL BE MONITORING FOR THE NEED FOR A COLD
WEATHER ADVISORY FOR SOME PORTION OF SUNDAY NIGHT THROUGH WEDNESDAY
NIGHT.
IN REGARDS TO LAKE EFFECT SNOW. WHEN THE AIR GETS THIS COLD IT WILL
EXCITE CLOUDS AND SNOW BUT THE DGZ WILL AT THE GROUND LEVEL AND WELL
BELOW THE MOIST LAYER SO POSSIBILITY OF LARGE FLAKES AND
ACCUMULATIONS GOES WAY DOWN. REGARDLESS, MIXED LAYERS WILL REACH UP
TO 5-6KFT WITH STEEP LAPSE RATES SO FLURRIES WITH A FEW LIGHT
SNOW SHOWERS WILL BE LIKELY.
MARINE...
COLD POST-FRONTAL NORTHWEST WIND ON THE ORDER OF 20 TO 30 KNOTS THIS
AFTERNOON DECREASES DOWN TO THE 10 TO 15 KNOT RANGE OVERNIGHT AS
ARCTIC HIGH PRESSURE BEGINS TO BUILD INTO THE AREA. A SMALL CRAFT
ADVISORY WAS ISSUED THROUGH THIS EVENING FOR THE NEARSHORE WATERS
AROUND THE THUMB WHERE LATEST ANALYSIS SHOWS ICE COVER HAS CLEARED
OUT, ALLOWING 4+ FOOT WAVES TO ENCROACH ON THE AREA. THE FRIGID
ARCTIC AIR MASS WILL TAKE RESIDENCE OVER THE GREAT LAKES TONIGHT
THROUGH WEDNESDAY. PREVAILING NORTHWEST TO NORTH WIND THROUGH SUNDAY
NIGHT TRENDS MORE WESTERLY ON MONDAY THEN WEST-SOUTHWEST ON TUESDAY
AND WEDNESDAY, THOUGH LOCAL FLUCTUATIONS IN WIND DIRECTION WILL
OCCUR AS THE RELATIVELY WARMER LAKES INDUCE A LAKE AGGREGATE SURFACE
TROUGH OVER LAKE HURON. GALES ARE NOT ANTICIPATED AT THIS TIME, BUT
LAKE EFFECT SNOW - HEAVY AT TIMES - AND PERIODS OF FREEZING SPRAY
CAN BE EXPECTED. A REBOUND IN TEMPERATURES IS THEN FORECAST FOR THE
LATE WEEK.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR LHZ421-441-442.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
AVIATION.....MR
DISCUSSION...DRK
MARINE.......TF
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