498
FXUS63 KAPX 251711
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
111 PM EDT FRI APR 25 2025
KEY MESSAGES
- INCREASING RAIN CHANCES INTO THIS AFTERNOON.
- LINGERING DREARY CONDITIONS EARLY SATURDAY.
- STRONG STORMS AND HEAVY RAIN POSSIBLE EARLY NEXT WEEK.
UPDATE
ISSUED AT 959 AM EDT FRI APR 25 2025
INHERITED FORECAST LARGELY REMAINS ON TRACK SO FAR TODAY WITH
SHOWERS OCCASIONALLY REACHING THE GROUND ACROSS PARTS OF THE
EASTERN U.P. SHOWERS STILL EXPECTED TO HOLD OFF UNTIL THIS
AFTERNOON FOR MUCH OF NORTHERN LOWER WITH JUST SOME MINOR
TEMPORAL/SPATIAL TWEAKS TO POPS BASED ON LATEST NEAR-TERM
GUIDANCE TRENDS.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 336 AM EDT FRI APR 25 2025
PATTERN/SYNOPSIS: HIGH PRESSURE IS ANCHORED OVER FAR NORTHERN
ONTARIO TODAY, THEN SHIFTS SOUTH TOWARD WESTERN LK SUPERIOR
TONIGHT. TO OUR SOUTH, LOW PRESSURE IS TRYING TO ORGANIZE AS
IT TRACKS FROM THE MID MS VALLEY TO THE SOUTHERN LAKES. THE LOW
WILL DEEPEN/ORGANIZE MORE SUBSTANTIALLY TONIGHT AS IT MOVES
TOWARD THE EASTERN LAKES. ALOFT, AN INBOUND SHORTWAVE TROF MOVES
ESE-WARD AND SHARPENS. IT WILL START TO CLOSE OFF RIGHT OVER OUR
HEADS SAT MORNING.
FORECAST: THE CORE OF DEEP MOISTURE WITH THIS SYSTEM GETS
SHUNTED FROM THE OH VALLEY TO THE EASTERN LAKES AND POINTS EAST.
MID-LEVEL DEFORMATION AND SOME COLD-CONVEYOR-BELT-TYPE DYNAMICS
IS OUR PRIMARY SOURCE OF MOISTURE/FORCING THIS FAR NORTH. SHOWER
COVERAGE WILL GRADUALLY INCREASE IN THE EASTERN UP THIS MORNING,
AS CONTINUED MID-LEVEL FORCING TURNS MORE OF OUR ONGOING
(MOSTLY) VIRGA INTO ACTUAL PRECIP. THIS PROCESS CONTINUES THRU
THE AFTERNOON, WITH A GRADUAL SE-WARD SHIFT IN AREA OF BEST
FORCING AND HIGHEST POPS. AROUND MIDDAY, CHANCY POPS RAMP UP
INTO PLN-TVC. MORE WIDESPREAD RAIN EXPANDS ACROSS THE ENTIRE
AREA THIS AFTERNOON, PERHAPS EXCEPTING THE FAR SE. TOTAL
RAINFALL TODAY IS 0.10-0.30" TODAY IN MOST OF THE AREA, HIGHEST
IN EASTERN UPPER. POPS AND QPF BOTH RAMP DOWN SUBSTANTIALLY
TONIGHT, WITH PRECIP DIMINISHING AND MOSTLY ENDING WEST OF I-75
IN BOTH PENINSULAS. HOWEVER, THE CLOSED 500MB LOW DIRECTLY
OVERHEAD WILL SUPPORT A CHANCE OF SHOWERS IN NE LOWER MI ALL THE
WAY TO 8AM.
HIGHS TODAY FROM UPPER 40S NORTH TO MID 60S NEAR GLADWIN. LOWS
TONIGHT IN THE 30S.
LONG TERM /SATURDAY THROUGH THURSDAY/
ISSUED AT 336 AM EDT FRI APR 25 2025
COL REGION SETTING UP OVERHEAD...WITH ELONGATED AREA OF ZONAL HIGH
PRESSURE TO OUR NORTH...AND ELONGATED TROUGH OF LOW PRESSURE
STRETCHING FROM THE LOWER GREAT LAKES TO SOUTHERN MI TO IA AND BACK
INTO EASTERN CO. THERMAL GRADIENT REMAINS RELATIVELY STEADFAST OVER
THE REGION, BOTH IN THE MID-LEVELS AND ALOFT...WITH A SURFACE TEMP
GRADIENT FROM THE UPPER 30S OVER THE EUP...TO THE 60S ACROSS
SOUTHERN LOWER MI. 100KT ZONAL UPPER JET LIFTING NORTHEASTWARD
TOWARD JAMES BAY TO OUR NORTH. SURFACE HIGH OVER THE SE US RESULTING
IN RETURN FLOW/MOISTURE ADVECTION INTO AFOREMENTIONED ELONGATED
BOUNDARY...WITH ABUNDANT CONVECTION ACROSS THE CENTER OF THE
CONUS...RELATED TO SUBTLE DIFLUENCE AHEAD OF A SHORTWAVE TROUGH
ALOFT...AND LONGER-WAVE SW FLOW FROM OFF THE COAST OF SOCAL. UPPER
RIDGE BALLOONING OVER THE CANADIAN ROCKIES...WITH A LOOSE POSITIVELY
TILTED TROUGH AXIS STRETCHING FROM A SWIRLY OF PV OVER EASTERN MT TO
A NORTHERN STREAM DISTURBANCE OVER THE CANADIAN PRAIRIES.
POTENT SHORTWAVE TROUGH ZIPS THROUGH THE REGION TODAY INTO TONIGHT,
DEEPENING A SURFACE CYCLONE TO OUR EAST OVER NEW ENGLAND BY
SATURDAY. HIGH PRESSURE WILL BUILD INTO OUR REGION SATURDAY, SLOWLY
SCRUBBING OUT LINGERING MOISTURE FROM WEST TO EAST...MOVING OVERHEAD
SATURDAY NIGHT. SURFACE HIGH WILL BE QUICK TO EXIT STAGE RIGHT...IN
RESPONSE TO POTENT TROUGH OVER THE SW US TREKKING FURTHER
INLAND...AND RESULTING IN DEVELOPMENT OF A POTENT SURFACE LOW WHICH
SHOULD TRACK ACROSS THE CENTRAL/NORTH CENTRAL US GOING INTO EARLY
WEEK. EXPECT STRONG RETURN FLOW AHEAD OF THIS FEATURE ACROSS THE
CENTRAL US...EVENTUALLY MAKING ITS WAY INTO THE UPPER GREAT LAKES
WITH TIME AS UPSTREAM TROUGHING APPROACHES...CROSSING THE AREA
TUESDAY...WITH A SLIGHTLY COLDER AIR MASS SETTLING IN FOR
MIDWEEK...AND CHANCES FOR CONTINUED UNSETTLED WEATHER HANGING ON
BEYOND THAT.
PRIMARY FORECAST CONCERNS:
SPRINKLES/FLURRIES/DRIZZLE EARLY SATURDAY?...MOISTURE STRIPS OUT
FROM THE TOP DOWN THROUGH THE DAY FROM WEST TO EAST. THINK IT WILL
TAKE MOST OF THE DAY TO MIX OUT LINGERING BOUNDARY LAYER MOISTURE,
WHICH COULD KEEP THINGS ON THE CLOUDY/COOL ORDER FOR MOST OF THE
DAY...AND HAVE DIALED TEMPS BACK FOR SATURDAY, WITH THE EXPECTATION
THAT HIGHS COULD STRUGGLE TO REACH 50 FOR PARTS OF THE AREA GIVEN
COLD AIR ALOFT AND NORTH FLOW HANGING ON, IN ADDITION TO THE CLOUDS.
ADDITIONALLY...THERE COULD BE JUST ENOUGH BOUNDARY LAYER MOISTURE TO
LEAD TO SOME SPRINKLES/FLURRIES SATURDAY MORNING, PARTICULARLY IN N
FLOW AREAS...AND MOST LIKELY THE INTERIOR HIGHER TERRAIN WHERE IT
SHOULD BE A BIT COOLER ANYHOW. WILL LOOK FOR IMPROVEMENTS FROM WEST
TO EAST THROUGH THE AFTERNOON...WITH A NICE SUNSET FOR MOST OF THE
AREA.
WHILE THINGS SHOULD BE DRYING OUT...DO HAVE TO WONDER IF THE
MOISTENING OF THE BOUNDARY LAYER FROM TODAY'S RAIN (AND WHATEVER
HANGS ON INTO SATURDAY) WILL BE ABLE TO KEEP OVERNIGHT LOWS SATURDAY
NIGHT FROM DROPPING TOO DRAMATICALLY...BUT THINK WE HAVE A DECENT
SHOT AT LOWS IN THE VICINITY OF FREEZING SATURDAY NIGHT, REGARDLESS.
ADDITIONALLY, WITH THE POTENTIAL FOR EFFICIENT RADIATIONAL COOLING
AND LINGERING BOUNDARY LAYER MOISTURE SATURDAY NIGHT...DO THINK SOME
PATCHY FOG COULD DEVELOP...
RAIN/STORMS EARLY NEXT WEEK...STILL A BIT OF UNCERTAINTY IN THE
DETAILS ATTM...BUT THE BROAD IDEA OF A STRONG SURFACE SYSTEM
CROSSING THE UPPER MIDWEST MONDAY THROUGH TUESDAY IS QUITE VALID.
STRONG SIGNALS FOR MOISTURE TRANSPORT INTO THE UPPER MIDWEST
STARTING EARLY MONDAY...AND ATTM, SUSPECT THE DEPARTING HIGH
PRESSURE COULD AT LEAST INITIALLY LIMIT EASTWARD EXPANSION OF
RAINFALL INTO OUR AREA. (PATTERN APPEARS PROGRESSIVE ENOUGH TO PUNT
THE SURFACE HIGH AND ATTENDANT DRY AIR ADVECTION OUT...AS MOISTURE
INCREASES FROM THE WEST.) PWATS BETWEEN 1-1.5INCH MOVING IN MONDAY
NIGHT INTO TUESDAY IS SOMEWHAT SIGNIFICANT (1-IN-10-YEAR ANNUAL
RETURN INTERVAL FOR VAPOR TRANSPORT THROUGH THE COLUMN)...THOUGH
AGAIN, CURRENT EXPECTED PROGRESSIVE NATURE OF THE SYSTEM SHOULD PUNT
THE BETTER MOISTURE ON EASTWARD RATHER QUICKLY, WHICH LIMITS THE
AMOUNT OF TIME HEAVIER RAIN POTENTIAL COULD HANG OUT OVER US. SOME
WEAKER STABILITY MOVING IN INITIALLY COULD ALSO AID IN THE POTENTIAL
FOR BETTER RAINFALL MONDAY NIGHT...AND DO WONDER IF
OVERNIGHT/MORNING CONVECTION WILL BE ABLE TO LIMIT THE EXTENT OF
ATMOSPHERE RECOVERY TUESDAY AS THE COLD FRONT SLIDES IN. MAY END UP
BEING SOMETHING WE HAVE TO WAIT FOR THE WHITES OF ITS EYES TO SEE.
ALL THIS BEING SAID...STILL A DEFINITE POSSIBILITY THAT THE BETTER
THETA-E ADVECTION AND THUS, RAINFALL POTENTIAL, COULD END UP WELL TO
OUR NORTH/NORTHWEST OVER CANADA...SO NOT A SOLID DEAL YET BY ANY
MEANS.
STORMS MONDAY NIGHT INTO TUESDAY COULD BE STRONG TO SEVERE, NOTING
POTENTIAL FOR STRONG WIND FIELDS ALOFT WITH THIS SYSTEM) APPEARS TO
COME MONDAY NIGHT INTO EARLY TUESDAY AS BETTER THETA-E ADVECTION
SLIPS INTO THE REGION...AND AS ANY UPSTREAM CONVECTION TRIES TO MOVE
EASTWARD. A POTENTIAL DRY SLOT PUNCHING IN TUESDAY COULD BOOST
POTENTIAL FOR DIURNAL HEATING (WITH UNUSUALLY WARM TEMPS
ALOFT)...LEADING TO AN ADDITIONAL SHOT AT STORMS TUESDAY AFTERNOON
ALONG THE COLD FRONT, WHICH COULD BE MORE SURFACE-BASED THAN THE
MORNING ROUND. CERTAINLY NOT IMPOSSIBLE THIS ENDS UP BEING MORE LIKE
ONE ROUND EARLY IN THE DAY THAT ENDS UP KEEPING THINGS CLOUDY/COOL
TO PRECLUDE DEVELOPMENT OF SURFACE-BASED INSTABILITY...BUT WITH THE
FRONT SLIDING THROUGH, AND THE INCREASE IN MOISTURE (IT WILL BE
MUGGY MONDAY NIGHT/TUESDAY)...DEFINITELY WORTH KEEPING AN EYE ON
TUESDAY AFTERNOON FOR OUR EASTERN/SOUTHEASTERN ZONES...EVEN IF WE
DON'T CLEAR UP VERY MUCH. (ASSUMING CURRENT GUIDANCE IDEAS HOLD AND
THIS DOESN'T CHANGE DRAMATICALLY IN THE NEXT FEW DAYS....) NOT EVEN
ENTIRELY IMPOSSIBLE SOME SNOW COULD MIX IN ON THE BACKSIDE OF THIS
SYSTEM ACROSS OUR NORTHERNMOST REGIONS GOING INTO TUESDAY NIGHT
BEHIND THE COLD FRONT...SO QUITE THE ROLLER COASTER WEATHER PATTERN,
INDEED.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 109 PM EDT FRI APR 25 2025
SHOWERS WILL BECOME MORE WIDESPREAD ACROSS NORTHERN MICHIGAN THIS
AFTERNOON WITH THE EXPECTATION THAT CIGS/VSBYS WILL GRADUALLY
LOWER. IFR CIGS EXPECTED AT CIU BY EARLY AFTERNOON BEFORE
GRADUALLY SPREADING SOUTH TO PLN BY LATE AFTERNOON AND
APN/TVC/MBL THIS EVENING. VSBYS LOWERED AT TIMES TO LOW-END
MVFR/HIGH-END IFR, ESPECIALLY LATER THIS AFTERNOON/EVENING.
OCCASIONALLY BREEZY NORTHEAST WINDS THIS AFTERNOON TURN MORE
NORTHERLY TONIGHT.
APX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 5 PM EDT
SATURDAY FOR LHZ348-349.
SMALL CRAFT ADVISORY UNTIL 5 PM EDT SATURDAY FOR LMZ345-346.
UPDATE...MJG
SHORT TERM...JZ
LONG TERM...NSC
AVIATION...MJG
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