999
FXUS63 KDTX 170900 CCA
AFDDTX
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
400 AM EST MON FEB 17 2025
KEY MESSAGES
- COLD START TO THIS MORNING WITH SINGLE DIGITS TO LOW TEENS AND
WIND CHILLS IN THE LOW SINGLE DIGITS TO NEGATIVE SINGLE DIGITS.
EVEN COLDER TUESDAY MORNING WITH WIND CHILLS FALLING TO -10F OR
LOWER.
- ADDITIONAL LAKE EFFECT SNOW SHOWERS EXPECTED TODAY WITH HIGHLY VARIABLE
ACCUMULATIONS TO AROUND A HALF INCH POSSIBLE. DRIER WEATHER
SETTLES IN TUESDAY AND EARLY WEDNESDAY.
- ADDITIONAL LIGHT SNOWFALL CHANCES WEDNESDAY EVENING INTO
THURSDAY MORNING WITH WELL BELOW NORMAL TEMPERATURES HOLDING
THROUGH THE MID TO LATE WEEK.
DISCUSSION
ARCTIC AIRMASS WILL BECOME ESTABLISHED TODAY INTO MID-WEEK. COLD
ADVECTION THIS MORNING IS SUPPORTING MAINTENANCE OF ELEVATED WINDS
AS MIXING DEPTHS REACH INTO STRONGER LOWER LEVEL FLOW ALOFT AND
PRODUCE SCATTERED GUSTS OF 20-25 MPH. THIS MAKES FOR A BLUSTERY
START TO THE DAY WITH WIND CHILLS THAT ARE EXPECTED TO BE AROUND
ZERO DEGREES (F) BY SUNRISE.
LOWER LEVEL FLOW TURNS MORE UNIFORMLY OUT OF THE W TODAY. MOISTURE
DEPTH WILL BE SHALLOW AS FORECAST SOUNDING SHOW PLENTY OF DRY AIR
ABOVE 5KFT ARRIVING WITH THIS ARCTIC AIR. OVERLAKE INSTABILITY WILL
BE RATHER HIGH GIVEN THE 850MB TEMPERATURES DOWN TO BELOW -20C
RESULTING IN DELTA TS GREATER THAN 20C. THIS WILL CONTINUE THE LAKE
EFFECT REGIME THROUGH TODAY WITH PLENTY OF CLOUDS AND SCATTERED SNOW
SHOWERS. LOOKING OVER THE FORECAST SOUNDINGS, THE BASE OF THE LAKE
MOISTURE PLUME RESIDES WITHIN THE NORTHERN END OF THE DGZ WITH GOOD
SATURATION WITH RESPECT TO ICE FOR THE EARLY AFTERNOON AS LOWER LEVEL
LAPSE RATES ARE MAXIMIZED AND THERE IS AN INCREASE IN DIURNAL
SURFACE BASED CAPE. THIS PROVIDES THE GREATEST OPPORTUNITY FOR AN
UPTICK IN WEST TO EAST ORIENTED LAKE EFFECT BANDS TO BECOME FIXATED
ACROSS PARTS OF THE CWA. GIVEN THE ANTICIPATED PERSISTENCE OF THIS
ACTIVITY OVER THE COURSE OF A FEW HOURS DURING THE AFTERNOON,
SNOWFALL AMOUNTS TO AROUND A HALF AN INCH WILL BE POSSIBLE. LACK OF
GREATER SYNOPTIC FORCING WILL OTHERWISE KEEP AMOUNTS IN CHECK, BUT
WOULD NOT BE SURPRISED IF SOME SPOTS ACHIEVE AN INCH IF THEY
EXPERIENCE A LONGER RESIDENCE TIME UNDER ANY CONCENTRATED SNOW BANDS.
SNOW AMOUNTS WILL BE HIGHLY VARIABLE AND LOCALIZED AS IS TYPICAL
WITH THIS TYPE OF ACTIVITY. TEMPERATURES COOL A LITTLE FURTHER INTO
THE EVENING AND DRAW THE BEST MOISTURE OUTSIDE OF THE DGZ BEFORE
ANTICYLONIC FLOW FURTHER CUTS OFF THE LAKE EFFECT SNOW POTENTIAL
TONIGHT.
AREAS OF CLEARING SKIES WILL MAY DEVELOP TONIGHT, THOUGH HOW MUCH
CLEARING AND HOW WIDESPREAD THE CLEARING IS STILL UNCLEAR. A STEADY
LIGHT WIND SHOULD AT LEAST PRODUCE WIND CHILLS DOWN TO AROUND
-10F FOR MUCH OF SOUTHEAST MICHIGAN. GREATER CONFIDENCE TO REACH ANY
COLD WEATHER ADVISORY CRITERIA OF -15F OR BELOW WILL BE ACROSS THE
THUMB, BUT WILL ALLOW FOR ONE MORE FORECAST CYCLE TO GAIN BETTER
CONFIDENCE IN CLOUD TRENDS BEFORE HOISTING ANY COLD HEADLINES.
SURFACE RIDGE EXTENDS INTO LOWER MICHIGAN TUESDAY AND WEDNESDAY
WHILE MORE ZONAL FLOW AT THE BASE OF CANADIAN TROUGH RESIDES OVER
THE GREAT LAKES. THE SETUP MORE LIKELY LEANS TOWARD LAKE ACTIVITY
STAYING CLOSER TO THE LAKES, SO WILL MAINTAIN A DRY FORECAST FOR
TUESDAY AND WEDNESDAY. A CLOSED LOW IS THEN FORECAST TO DEVELOP OVER
THE CENTRAL GREAT LAKES WEDNESDAY EVENING INTO THURSDAY OFFERING THE
NEXT BEST CHANCE FOR ACCUMULATING SNOWFALL. HOWEVER, MOISTURE WILL BE
LACKING AND SHOULD KEEP ACCUMULATIONS ON THE LIGHTER END.
TEMPERATURES EXPECTED TO REMAIN WELL BELOW THE AVERAGE WITH DAILY
HIGHS IN THE 20S FOR THE LATE WEEK PERIOD.
MARINE
ARCTIC AIR WILL CONTINUE TO FILL IN ACROSS THE GREAT LAKES TODAY IN
THE WAKE OF A COLD FRONT. THIS WILL SUSTAIN BREEZY CONDITIONS,
PARTICULARLY ACROSS LAKE HURON WITH THE NORTHWEST FLOW, WHERE GUSTS
AROUND 30 KNOTS WILL BE POSSIBLE. THIS WILL ALSO GENERATE FREEZING
SPRAY ACROSS THE GREATER PORTION OF LAKE HURON THROUGH TOMORROW
MORNING, WHERE A FREEZING SPRAY WARNING IS IN PLACE. LAST, LAKE
EFFECT SNOW SHOWERS, INCLUDING SNOW SQUALLS, WILL BE LIKELY THROUGH
TOMORROW. SNOW SQUALL POTENTIAL WILL PEAK LATE THIS MORNING INTO
EARLY TOMORROW MORNING OVER NORTH AND CENTRAL LAKE HURON, TIED TO
THE FAVORABLE NORTHWEST FETCH AND COLDEST PUSH OF ARCTIC AIR. THE
PRESSURE GRADIENT WILL DECREASE IN INTENSITY THROUGH THE MIDWEEK
WHICH WILL DIMINISH WIND SPEEDS AND GUST POTENTIAL.
PREV DISCUSSION
ISSUED AT 1144 PM EST SUN FEB 16 2025
AVIATION...
THE LOW LEVEL WIND FIELDS OVER SOUTHERN LAKE MICHIGAN WILL BACK FROM
NORTHWEST TO WESTERLY TONIGHT THRU MONDAY MORNING. STEADY WESTERLY
FLOW WILL THEN PERSIST INTO MONDAY NIGHT. ONGOING ARCTIC AIR
ADVANCING ACROSS THE LAKE WILL MAINTAIN THE MOISTURE FLUX TO SUPPORT
CONTINUED STRATO CU AND SOME FLURRIES/LIGHT SNOW SHOWERS THROUGH AT
LEAST MONDAY AFTERNOON. WITH AN ONGOING DEPARTURE OF DEEP LAYER
MOISTURE AND LOW LEVEL DRY AIR ADVECTION, TRENDS SUGGEST CEILINGS
TRENDING TO PREDOMINATELY VFR. SOME PARTIAL CLEARING DOES LOOK
POSSIBLE TOWARD DAYBREAK IN LIGHT OF THE DEGREE OF DRY AIR ARRIVING
WITH THIS ARCTIC AIRMASS. THE ONSET OF DIURNAL MIXING ON MONDAY WILL
SUPPORT SOME REDEVELOPMENT OF THE LAKE MICHIGAN MOISTURE PLUME, ALSO
SUPPORTING SOME CONTINUED FLURRIES AND SNOW SHOWERS. THE PERSISTENCE
OF THE COLD AIR ADVECTION WILL SUSTAIN SOME DEGREE OF LOW LEVEL
MIXING AND GUSTINESS TO THE WESTERLY WINDS.
DTW THRESHOLD PROBABILITIES...
* MEDIUM IN CEILING AT OR BELOW 5000 FEET THROUGH THE TAF PERIOD.
* LOW IN CROSSWIND THRESHOLDS BEING MET TONIGHT AND MONDAY.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST TUESDAY FOR LHZ361>363.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST TUESDAY FOR LHZ462-463.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...AA
MARINE.......AM
AVIATION.....SC
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