135
FXUS63 KDTX 290350
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1150 PM EDT MON APR 28 2025
KEY MESSAGES
- RECORD/NEAR RECORD WARMTH TOMORROW AS HIGH TEMPERATURES PUSH INTO
THE UPPER 70S TO MID 80S. IT WILL BE WINDY AS WELL, WITH PEAK
SOUTHWEST-WEST GUSTS OF 40-45 MPH IN THE AFTERNOON.
- THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO
TUESDAY. IF ANY THUNDERSTORMS DEVELOP TOMORROW AFTERNOON (11 AM - 5
PM), THEY WILL HAVE THE POTENTIAL TO BECOME SEVERE AND PRODUCE
DAMAGING WIND GUSTS. OTHERWISE, STORMS LATE TONIGHT/TOMORROW
MORNING WILL BE CAPABLE OF SMALL HAIL AND SUB-SEVERE GUSTY WINDS.
- MUCH COOLER TUESDAY NIGHT INTO WEDNESDAY, WITH FROST POSSIBLE
NORTH OF M-59 AROUND SUNRISE WEDNESDAY.
- SOAKING RAIN ARRIVES LATE WEDNESDAY NIGHT-THURSDAY AND PERSISTS
INTO EARLY FRIDAY MORNING.
AVIATION
A DRY AIRMASS AT THE SURFACE AND DIFFERENTIAL WARM ADVECTION ALOFT
INTO THE MIDLEVELS WILL LEAD TO STABLE VFR CONDITIONS OVERNIGHT.
DEEPER MOISTURE ARRIVES AS CYCLONIC FLOW TRAJECTORIES TAKE HOLD
AFTER 10Z. ISOLATED TO SCATTERED SHOWERS WILL BE POSSIBLE AND
INCLUDED A TEMPO GROUP. THUNDERSTORM DEVELOPMENT IS THEN POSSIBLE
ALONG A COLD FRONT BETWEEN 17-21Z. UNCERTAINTY EXISTS ON THE COVERAGE
OF CONVECTION ALONG THE FRONT AND WHETHER OR NOT THE BETTER
DEVELOPMENT WILL OCCUR TO THE EAST OF THE TAF SITES. DID MAINTAIN A
PROB30 GROUP FOR THE AFTERNOON +TSRA POTENTIAL. IF ACTIVITY OCCURS IT
WILL BE VERY BRIEF.
DTW THRESHOLD PROBABILITIES
* LOW FOR CEILINGS AOB 5000 FEET LATE TONIGHT AND TUESDAY MORNING.
* LOW FOR THUNDERSTORMS TUESDAY.
PREV DISCUSSION
ISSUED AT 257 PM EDT MON APR 28 2025
DISCUSSION...
ACTIVE UPPER LEVEL PATTERN WITH SEVERAL UPPER LEVEL WAVES BACK
ACROSS THE ROCKIES WITH A STRONG NORTHERN STREAM UPPER LEVEL TROUGH
TRACKING EAST THROUGH CENTRAL CANADA. INTERACTION OF MULTIPLE WAVES
MAKES FOR DIFFICULT FORECAST TOMORROW. THE SEASONABLY STRONG SURFACE
LOW (994 MB) ENTERING WEST CENTRAL MINNESOTA WILL BE TRACKING OFF TO
THE NORTHEAST AND REACHING THE CENTRAL ONTARIO/QUEBEC BORDER TOWARD
12Z TUESDAY, ABSORBED BY THE NORTHERN STREAM TROUGH. ALTHOUGH THE
MAIN UPPER LEVEL WAVE/COLD POOL (-24 C AT 500 MB) WILL LINGER BACK
ACROSS THE FOUR CORNERS REGION, THERE DOES APPEAR TO BE A
SHORTWAVE/JET STREAK COMING OUT, ENHANCING THE UPPER LEVEL JET OVER
THE CENTRAL GREAT LAKES REGION FOR TOMORROW. THE QUESTION FOR
TOMORROW CONTINUES TO BE TIMING OF THE COLD FRONT AND IF WE CAN
OVERCOME WARM MID LEVELS AND ERODE THE CAP IN PLACE. LOCATION OF THE
RIGHT ENTRANCE FORCING OF THE UPPER LEVEL JET WILL BE A BIG FACTOR,
AND THERE ARE STILL DISCREPANCIES. STRONG SOUTHWEST LOW LEVEL JET TO
TRANSPORT A GOOD DEAL OF MOISTURE INTO LOWER MICHIGAN, WITH 850 MB
DEW PTS PUSHING 12 C AND 700 MB DEW PTS REACHING AROUND ZERO TUESDAY
MORNING, ALL NEAR DAILY RECORD DAILY VALUES FOR SOUTHEAST MICHIGAN
SOUNDING CLIMATOLOGY. MOISTURE AXIS AND MID LEVEL INSTABILITY AXIS
ALREADY BEGINS TO PULL EAST BY MID DAY. EVEN SO, MLCAPES EXPECTED TO
BUILD TO 1000-2000 J/KG ON TUESDAY, WITH NAM EXCEEDING 2500 J/KG
WHILE 12Z HRRR IS CLOSER TO SBCAPES OF 2000 J/KG WITH THE CAP
HOLDING AS THE COLD FRONT MOVES THROUGH DURING THE MID AFTERNOON.
UNIDIRECTIONAL FLOW IN THE LOW LEVELS WITH THE FRONT, AND NOT MUCH
LOW LEVEL CONVERGENCE MAKES THIS CHALLENGING FORECAST WITH THE
AMOUNT OF CONVECTION DEVELOPING ALONG THE FRONT, IF ANY. WITH THE
STRONG WIND FIELDS AND PREVIOUSLY MENTIONED CAPES, DAMAGING WINDS
WILL BE MAIN HAZARD WITH THE POTENTIAL SEVERE STORMS. SPC DAY 2
CONTINUES TO MAINTAIN SLIGHT CHANCE RISK, BUT REMAINS CONDITIONAL,
AND REALLY CAN'T JUSTIFY CARRY MORE THAN CHANCE POPS (20-40%) FOR
SHOWERS/THUNDERSTORMS WITH THE AGGRESSIVE MID LEVEL DRY SLOT
OVERLAPPING THE COLD FRONT. ELEVATED ACTIVITY AROUND 12Z TUESDAY
ACTUALLY HAS BETTER CHANCE (30-50%) WITH THE STEEP MID LEVEL LAPSE
RATES. REGARDLESS OF STORMS DURING TUESDAY, WITH THE BOUNDARY LAYER
MIXING DURING THE DAY AS TEMPS REACH NEAR/RECORD VALUES IN THE UPPER
70S TO MID 80S DEGREES, EXPECTING WIND GUSTS TOPPING OUT 40-45 MPH
RANGE. THIS IS SUPPORTED BY LOCAL PROBABILISTIC GUIDANCE AND A WIND
ADVISORY IS POSSIBLE WITH THE 50+ KNOTS OF WESTERLY FLOW AT THE 850
MB LEVEL.
COOLER AND DRY WITH NEAR NORMAL TEMPS ON WEDNESDAY AS RIDGING AT ALL
LEVELS ARRIVE. WITH CLEAR SKIES AND WINDS GOING CALM TOWARD SUNRISE,
MINS IN THE LOWERS 30S (NORTH) TO LOWER 40S (SOUTH) EXPECTED,
RESULTING IN FROST NORTH OF M-59.
A MOISTURE LADEN LOW PRESSURE SYSTEM THEN ON TRACK TO MOVE INTO
LOWER MICHIGAN ON THURSDAY, PHASING AND DEEPENING WITH THE NORTHERN
STREAM. THUS, MOVEMENT WILL BE SLOW, AND NOT EXITING THE CENTRAL
GREAT LAKES UNTIL FRIDAY MORNING. TOTAL RAINFALL AMOUNTS OF HALF AN
INCH TO ONE INCH SEEM LIKELY AT THIS POINT, WITH THE POTENTIAL FOR
HIGHER AMOUNTS WITH MESOSCALE BANDING AND/OR CONVECTION.
MARINE...
BROAD AREA OF HIGH PRESSURE HAS EXPANDED ACROSS THE EAST COAST WHILE
A STRONG AREA OF LOW PRESSURE HAS MOVE OVER THE MIDWEST ON IT'S WAY
NORTHEAST THROUGH THE NORTHERN GREAT LAKES TODAY. THE LOW WILL
CONTINUE INTO ONTARIO/QUEBEC TONIGHT WHILE THE COLD FRONT REMAINS
DRAPED BACK TO THE SOUTHWEST. THIS SETUP PLACES THE EASTERN LAKES IN
A STRONG WARM ADVECTION SETUP TODAY. THE GRADIENT WILL TIGHTEN
BETWEEN THE TWO MAIN SYSTEMS BUT THE WARM AIR WILL BRING STABILITY
TO THE REGION LIMITING THE GUST POTENTIAL THROUGH TONIGHT. WINDS
SHOULD STILL GET UP TO AROUND 25 KNOTS THUS SMALL CRAFT ADVISORIES
ARE IN EFFECT FOR ALL NEARSHORE ZONES AND LAKE ST CLAIR TONIGHT
THROUGH TUESDAY. A COLD FRONT THEN SWEEPS THROUGH TUESDAY AFTERNOON
WITH POSSIBLE SHOWERS AND THUNDERSTORMS. MAIN QUESTION IS HOW DO THE
WINDS RESPOND BEHIND THE COLD FRONT FOR THE EVENING? MODELS AND
ENSEMBLE SOLUTIONS SHOW THE POTENTIAL FOR A SHORT WINDOW OF GALES IN
THE AFTERNOON AROUND 4PM TO 8PM ACROSS NORTHERN LAKE HURON AND
SAGINAW BAY. PROBABILISTIC GUIDANCE SHOWS ONLY ABOUT A 30-40% CHANCE
OF GALES IN THAT TIME. HAVE DECIDED TO HOLD OFF ON A GALE WATCH OR
WARNING AT THIS TIME DUE TO LOW CONFIDENCE AND SHORT WINDOW OF TIME.
SO EXPECTATIONS ARE FOR A PERIOD OF STRONGER FLOW TO AROUND 30 KNOTS
WITH A FEW HOURS WITH ISOLATED GUSTS TO GALES. WILL CONTINUE TO
MONITOR FOR TRENDS IN GALE POTENTIAL. HIGH PRESSURE BUILDS IN ON
WEDNESDAY WITH WIND BECOMING LIGHT AND VARIABLE. THE NEXT LOW IS
THEN SET TO ARRIVE THURSDAY INTO FRIDAY.
CLIMATE...
THE RECORD HIGHS FOR TUESDAY, APRIL 29TH.
DETROIT: 83 DEGREES (SET IN 1899)
FLINT: 82 DEGREES (SET IN 1942)
SAGINAW: 84 DEGREES (SET IN 1970)
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 10 PM EDT TUESDAY FOR LHZ442-443.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT TUESDAY FOR LHZ421-422-441.
LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 10 PM EDT TUESDAY FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT TUESDAY FOR LEZ444.
AVIATION.....CB
DISCUSSION...SF
MARINE.......DK
CLIMATE......SF
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