559
FXUS63 KAPX 270721
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
321 AM EDT SUN APR 27 2025
KEY MESSAGES
- QUIET AND WARMER TODAY AND TONIGHT
- STRONG TO SEVERE THUNDERSTORMS POSSIBLE MONDAY NIGHT INTO
VERY EARLY TUESDAY
- WIDESPREAD BREEZY/WINDY CONDITIONS EXPECTED MONDAY NIGHT INTO
TUESDAY
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 322 AM EDT SUN APR 27 2025
PATTERN/SYNOPSIS: HIGH PRESSURE WILL BE OVERHEAD THIS MORNING,
AND WILL ONLY SLOWLY HEAD TOWARD THE EASTERN LAKES THRU TONIGHT.
FORECAST: QUIET, WITH ABUNDANT DRY AIR AT LOW LEVELS. SOME WEAK
RETURN FLOW GETS UNDERWAY THIS AFTERNOON, AND SLOWLY INCREASES
THRU TONIGHT. BUT THE FLOW COMING OFF THE DEPARTING HIGH IS
STILL DRY, EVEN IF STARTING TO TREND LESS DRY TONIGHT. THOUGH WE
DO SEE SOME HIGH CLOUDS AT TIMES, ESPECIALLY IN THE NORTH HALF
THIS AFTERNOON, DIURNAL HEATING AND DEEP MIXING WILL MIX OUT BL
MOISTURE. THIS WILL ESPECIALLY BE THE CASE IN THE USUAL INTERIOR
DRIER SPOTS. USED NBM10PCT AS GUIDANCE FOR DEW POINTS THIS
AFTERNOON, WHICH RESULTS IN RHS BOTTOMING OUT AROUND 20%.
THANKFULLY WE ONLY HAVE A BIT OF A SOUTH WIND THIS AFTERNOON,
MORE SO IN NW LOWER MI (WHERE THE PRESSURE GRADIENT STARTS TO
TIGHTEN 1ST). EVEN THERE, WINDS ARE WEAK ENOUGH FOR SIGNIFICANT
LAKE BREEZE PENETRATION THIS AFTERNOON. WILL HIGHLIGHT THE DRY
CONDITIONS IN FIRE WX PRODUCTS, BUT A STRONGER RESPONSE IS NOT
NEEDED.
WARM-ADVECTION CLOUD COVER REMAINS CONSIDERABLE IN THE NORTH
THIS EVENING, WITH CLOUDS TENDING TO DECREASE FOR A BIT
OVERNIGHT.
HIGHS TODAY IN THE 60S IN THE INTERIOR, MUCH COLDER ON THE
BEACHES AS ONSHORE WINDS DEVELOP. LOWS TONIGHT NEAR 40F TO THE
MID 40S.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 322 AM EDT SUN APR 27 2025
PATTERN SYNOPSIS/FORECAST:
BIG BALL OF VORTICITY SPINNING OVER THE WESTERN US...WITH
SOUTHWESTERLY FLOW ALOFT AMPLIFYING UPPER RIDGE NOW CENTERED OVER
THE CENTRAL US. VORT SWIRLY AND DEEPENING SURFACE LOW THAT HAD
PESTERED US FRIDAY/SATURDAY MORNING NOW OVER EASTERN CANADA/NEW
ENGLAND. SURFACE HIGH CENTERED LARGELY OVER LAKE MI AS OF 3Z...WITH
SUBTLE NORTHERLY FLOW KEEPING DRY AIR OVER THE REGION...LEAVING US
OTHERWISE QUIET AND COOL. NEARLY MERIDIONAL FLOW IN THE LOW-LEVELS
UP THROUGH THE PLAINS OFF THE GULF...AIDING IN A PLUME OF BETTER
MOISTURE SNEAKING NORTHWARD TOWARD THE DAKOTAS...ALONG/AHEAD OF
SUBTLE PV MAXES IN THE LONGWAVE BUT SLIGHTLY DISCONNECTED TROUGH
AXIS STRETCHING FROM AFOREMENTIONED VORT BALL OVER SOCAL/NV
NORTHWARD INTO THE CANADIAN ROCKIES. NORTHERN STREAM ENERGY TRYING
TO BE A LITTLE MORE PROGRESSIVE...WITH SURFACE COLD FRONT DRAPING
SOUTHWARD ACROSS SOUTHWEST CANADA.
RIDGE AXIS TO HANG OVER US TODAY...DRIFTING EASTWARD AS CALIFORNIA
VORT BALL SPINS FURTHER INLAND. LONGWAVE TROUGH AXIS WILL BECOME
POSITIVELY TILTED AS NORTHERN STREAM ENERGY PROGRESSES MORE QUICKLY
THROUGH THE FLOW MONDAY/TUESDAY...DRIVING UNSEASONABLY DEEP SURFACE
LOW ALONG A SW-NE ORIENTED BOUNDARY ACROSS THE MIDWEST MONDAY NIGHT
INTO TUESDAY...BRINGING POTENTIAL FOR STRONG TO SEVERE STORMS FOR
PARTS OF THE MIDWEST, INCLUDING THE UPPER GREAT LAKES, FOR THIS
PERIOD. HIGH PRESSURE AND A COOLER AIR MASS BRIEFLY SLIDES IN BEHIND
THE FRONT LATER TUESDAY INTO WEDNESDAY...BUT NEXT TROUGH AXIS WILL
ALREADY BE ON OUR DOORSTEP BY MIDWEEK, WITH STRONG JET OVER THE
PACIFIC AIDING IN PROGRESSIVE FLOW. GUIDANCE STILL SIGNALING,
PERHAPS A BIT BETTER WITH THE CURRENT MODEL RUNS, THE POTENTIAL FOR
THIS TROUGH TO CLOSE OFF ONCE IT GETS TO OUR EAST...PLACING A BIG
ROADBLOCK IN THE FLOW IF THIS COMES TO FRUITION. STILL QUITE A BIT
OF UNCERTAINTY IN HOW THIS EVOLVES...BUT WORTH KEEPING AN EYE ON, AS
IT COULD CERTAINLY LEAD TO A PERIOD OF COOL/DREARY WEATHER LATE
WEEK/NEXT WEEKEND IF THIS IDEA HOLDS.
PRIMARY FORECAST CONCERNS:
SEVERE STORM POTENTIAL MONDAY NIGHT INTO TUESDAY...
STILL HAVE CONCERNS THAT THERE COULD BE SOME WARM ADVECTION RAIN
EARLY MONDAY THAT COULD THROW A WRENCH INTO THE CURRENT FORECAST.
FOR WHAT IT'S WORTH...THE ADDITION OF LOW-LEVEL MOISTURE WITH ANY
MORNING PRECIP COULD VERY WELL DESTABILIZE THE ENVIRONMENT AS WELL
AS ANY DIURNAL HEATING COULD...AND NOT SURE THAT DIURNAL HEATING
WILL NECESSARILY BE A CONCERN FOR US. FROPA HERE IN NORTHERN
MICHIGAN LOOKS TO TAKE PLACE AT SOME POINT AFTER MIDNIGHT AS THE
FRONT SLIDES THROUGH FROM NW TO SE. EXPECT THERE SHOULD BE FORCING
ALONG THE FRONT ITSELF...AND THINK CONVECTIVE INSTABILITY WILL BE
FURTHER ENHANCED AFTER MIDNIGHT, TOO, AS A DRY SLOT POKES INTO THE
AREA. THINK THESE ITEMS WILL AID IN FOCUSING THE BEST OPPORTUNITY
FOR CONVECTIVE ACTIVITY MONDAY NIGHT INTO TUESDAY MORNING, WITH SOME
LINGERING ACTIVITY POSSIBLE TOWARD SAGINAW BAY/LAKE HURON COAST
GOING INTO EARLY TUESDAY AFTERNOON....THOUGH RECENT GUIDANCE TRENDS
HAVE BEEN SUGGESTING THE FRONT WILL EXIT QUICKER THAN PREVIOUSLY
THOUGHT.
FOR US...THINK OUR GREATEST CONCERNS WILL BE WIND AND HAIL. 50-60+KT
LOW-LEVEL JET (ANOMALOUSLY SO) PASSING OVERHEAD WILL NOT ONLY BE
PRESENT FOR DOWNWARD MOMENTUM TRANSFER CONCERNS (EVEN WITH THE
PRESENCE OF AN INVERSION)...BUT ALSO SUPPORT STRONG SHEAR TO
POTENTIALLY LEAD TO STRONGER UPDRAFTS IN ANY CONVECTION THAT IS A
LITTLE MORE DISCRETE...THUS INCREASING THE HAIL THREAT. DISCRETE
CONVECTION IS CERTAINLY POSSIBLE AS DEEP-LAYER SHEAR VECTORS ARE NOT
TOTALLY PARALLEL TO THE BOUNDARY...AND DISCRETE CONVECTION COULD
CHUCK AN INCREASED POTENTIAL FOR TORNADIC ACTIVITY INTO THE
MIX...THOUGH BETTER POTENTIAL FOR LEGITIMATELY SURFACE-BASED
ACTIVITY (EVEN OVERNIGHT!) MAY BE UPSTREAM OVER WI. HOWEVER...WITH
SHEAR VECTORS PARTLY PARALLEL TO THE BOUNDARY...THINK THERE WILL BE
SOME UPSCALE GROWTH INTO MORE LINEAR MODES WITH TIME, WHICH WOULD
FAVOR A DAMAGING WIND THREAT OVERNIGHT INTO EARLY TUESDAY
MORNING...POTENTIALLY EVEN ACROSS AREAS STILL TRYING TO RECOVER FROM
THE ICE STORM. EMBEDDED SPIN-UPS CERTAINLY NOT OUT OF THE QUESTION
WITH ANY LINEAR ACTIVITY.
STILL CONCERNED ABOUT RAINFALL POTENTIAL FOR OUR AREA, AS IT'S HARD
TO IGNORE THE STRONG SIGNALS FOR ANOMALOUS MOISTURE IN THE PRESENCE
OF STRONG FORCING. SAVING GRACE FOR US AS FAR AS EXCESSIVE RAINFALL
GOES...IS THAT THIS BOUNDARY APPEARS RATHER PROGRESSIVE, WHICH COULD
LIMIT RESIDENCE TIME FOR HEAVIER RAINFALL FOR US...AND KEEP RAINFALL
TOTALS A BIT MORE IN CHECK. CURRENT SIGNALS SUGGEST THE EXCESSIVE
RAINFALL POTENTIAL WILL BE TO OUR NORTHWEST MONDAY NIGHT INTO
TUESDAY, BUT NOT IMPOSSIBLE THAT CONVECTION COULD TRAIN A BIT ACROSS
PART OF THE YOOP MONDAY/MONDAY NIGHT BEFORE THINGS TURN MORE
PROGRESSIVE OVERNIGHT.
WIDESPREAD BREEZY NON-THUNDERSTORM WINDS MONDAY NIGHT INTO
TUESDAY...STRONG SURFACE PRESSURE GRADIENT WITH THIS SYSTEM
CERTAINLY SUPPORTIVE OF SUSTAINED S-SW WINDS 10-20KTS OR BETTER AT
TIMES MONDAY...CONTINUING RIGHT ON INTO TUESDAY AS WINDS SWITCH
AROUND TO THE WEST AND EVENTUALLY NW BEHIND THE FRONT (AND A
SECONDARY FRONT IN THE LATTER PORTION OF THE DAY). SOME SIGNALS FOR
AN ENHANCED PRESSURE GRADIENT ON THE BACKSIDE OF THE DEPARTING LOW
OVER THE EASTERN YOOP, WHICH BEARS WATCHING. ADDITIONALLY...WITH THE
DRAMATIC PRESSURE CHANGES TUESDAY WITH THE FRONT...AND THE AMOUNT OF
WIND PRESENT WITH THIS SYSTEM...WOULD NOT BE SURPRISED TO SEE A
BOOST IN WIDESPREAD, NON-THUNDERSTORM WIND GUSTS A FEW HOURS EITHER
SIDE OF FROPA. GOOD CONFIDENCE ATTM IN GUSTS 30-35KTS ON TUESDAY
MORNING FROM PROBABILISTIC DATA...AND DO THINK WE MAY NEED TO KEEP
AN EYE ON POTENTIAL FOR A WIND ADVISORY FOR MONDAY NIGHT INTO
TUESDAY ON TOP OF WHATEVER CONVECTIVE WINDS COME THROUGH THE REGION.
CERTAINLY NOT IDEAL FOR AREAS THAT ARE STILL RECOVERING FROM THE ICE
STORM.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1123 PM EDT SAT APR 26 2025
VFR CONDITIONS THROUGH THE PERIOD, WITH MOSTLY SUNNY SKIES THIS
MORNING GIVING WAY TO JUST SOME INCREASING HIGH CLOUDS THIS
AFTERNOON AND EVENING. LIGHT WINDS WITH LOCAL AFTERNOON LAKE
BREEZE DEVELOPMENT EXPECTED.
APX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
SHORT TERM...JZ
LONG TERM...FEF
AVIATION...MSB
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