067
FXUS63 KAPX 290503
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
103 AM EDT SAT MAR 29 2025
KEY MESSAGES
- SIGNIFICANT ICE ACCUMULATIONS DEVELOPING ACROSS EASTERN UPPER
AND PARTS OF NORTHERN LOWER MICHGIAN TONIGHT.
- POTENTIAL FOR ANOTHER ROUND OF SIGNIFICANT ICE DEVELOPS ON
SATURDAY.
- ANOTHER ROUND OF ACCUMULATING FREEZING RAIN/ICING RETURNS
SATURDAY EVENING/NIGHT. FREEZING RAIN FOCUSES MOSTLY ON
ELEVATED TERRAIN OF NORTHERN LOWER ALONG WITH THE STRAITS.
- VARIABLE WEATHER CONDITIONS SWING ACROSS NORTHERN LOWER THIS SUNDAY
AS WARM AIR BUILDS WITH SHOWER/STORM CHANCES, FOLLOWED BY A
COLD FRONT RETURNING MIXED PRECIP AND SNOW SUNDAY NIGHT INTO
MONDAY.
- QUIET AND COOL CONDITIONS BUILD THROUGH THE FIRST HALF OF
NEXT WEEK. ADDITIONAL PRECIPITATION CHANCES RETURN TO THE
GREAT LAKES REGION AROUND THE WEDNESDAY/THURSDAY TIMEFRAME.
UPDATE
ISSUED AT 1150 PM EDT FRI MAR 28 2025
ISSUED A WINTER WX ADVIS EARLIER FOR GLR TO APN FOR NIGHTTIME
ACTIVITY, RIGHT UP TO WHEN THE WATCH KICKS IN AT 12Z. DIDN'T
FEEL RIGHT/COMFORTABLE ABOUT DECIDING TO UPGRADE SATURDAY AND
BEYOND TO A WARNING (THOUGH THAT SEEMS/FEELS LIKELY AT THE
MOMENT). VERY MARGINAL TEMPS WILL LIMIT ICE ACCUMS EVEN WITH
BRIEF HIGH PRECIP RATES. AT LEAST THAT'S THE PLAN.
ISSUED AT 957 PM EDT FRI MAR 28 2025
LINE OF DEEP CONVECTION EXTENDS ENE-WSW THRU THE STRAITS BACK
INTO NE WI. STRATIFORM PRECIP IS FALLING NORTH OF THIS MCS,
CONTRIBUTING TO MESSY WINTER WX IN NORTHERN AREAS. ICE STORM
WARNING SEEMS TO WORKING OUT FINE IN EASTERN UPPER...THE SAULTS
HAVE GONE BACK TO MOSTLY SNOW, BUT MORE IN THE WAY OF A MIX
WAS/IS EXPECTED THAT FAR NORTH AS THE NORTH TIP OF THE WARM
NOSE ALOFT BOUNCES AROUND SOME. THAT WARM NOSE IS +8C AT 895MB
OVER THE OFFICE, PER THE OBSERVED 00Z SOUNDING.
WHAT TO DO FURTHER SOUTH? HEAVY PRECIP RATES ARE CLEARLY
INBOUND INTO THE M-68 AND EVENTUALLY M-32 COUNTIES. PLN IS 32/28
(A TOUCH OF ROOM FOR EVAP COOLING, IN THEORY), WITH PERIODS OF
FZDZ/-FZRA ALREADY. CHEBOYGAN 30/30, ROGERS 31/30. SIGNIFICANT
FZRA SEEMS INEVITABLE THERE...BUT WHAT WILL ACCUMS BE? WE'LL
REMAIN AT OR JUST BARELY BELOW FREEZING, AND PRECIP RATES WILL
BE HIGH ENOUGH FOR A LOT OF THAT WATER TO RUN OFF WITHOUT
FREEZING. PLUGGED IN THE LATEST/GREATEST FOR QPF GUIDANCE
TONIGHT, AND MADE A FEW TWEAKS TO THE T CURVE (WHICH SHOULD
STILL BE VERY SLOWLY FALLING OVER THE TIP OF THE MITT COUNTIES,
WITH COLD ADVECTION AND EVAP COOLING WINNING OVER LATENT HEAT
RELEASE AS RAIN FREEZES). GET ICE TOTALS IN EXCESS OF 0.25" THRU
SAT MORNING OVER CENTRAL/NORTHERN EMMET CO, NORTHERN CHEBOYGAN,
AND NW AND CENTRAL PRESQUE ISLE.
GIVEN THE ABOVE, UPGRADED THOSE COUNTIES TO ICE STORM WARNINGS
FOR THE REST OF THIS INITIAL EVENT. ARE COUNTIES FURTHER SOUTH
GOING TO NEED HEADLINES? IT'S GOING TO BE VERY TOUCH-AND-GO OVER
THE HIGH TERRAIN (GLR/APX/ATLANTA), BUT THE T CURVE IS JUST
SLIGHTLY WARMER THAT FAR SOUTH. NOTHING YET AS FAR AS
HEADLINES, BUT AM NERVOUS.
SHORT TERM /THROUGH SUNDAY/
ISSUED AT 251 PM EDT FRI MAR 28 2025
PATTERN SYNOPSIS/FORECAST:
ALL EYES DIRECTED AT MULTI-LAYER FRONTAL FEATURES AND ATTENDANT
INTENSE THERMAL GRADIENT FOUND ACROSS THE GREAT LAKES EARLY THIS
AFTERNOON. ACTUAL FOCUSED SURFACE FRONT/WARM FRONT SLOWLY BOWING
NORTH FROM SOUTHERN MINNESOTA TO SOUTHWEST MICHIGAN, WITH THIS FRONT
DELINEATING MUCH COOLER AIR TO THE NORTH AND SPRINGTIME WARMTH TO
ITS SOUTH. TWO AREAS OF ORGANIZED PRECIPITATION, ONE ALONG AND NORTH
OF THAT AFORMENTIONED WARM FRONT (DRIVEN BY INTENSE AND MOISTURE
RICH ISENTROPIC UPGLIDE)...WITH ANOTHER ZONE OF MIXED WINTRY
PRECIPITATION ARCHING FROM NORTHWEST TO SOUTHEAST ACROSS SOUTHERN
ONTARIO INTO LAKE SUPERIOR (WITH THIS AREA BEEN DRIVEN BY DEEP
FRONTOGENETICAL RESPONSE ALONG RIGHT ENTRANCE REGION OF 120+ KNOT
UPPER LEVEL JET). PRIMARY CONCERN TONIGHT WILL FOCUS ON THE LATTER
AS IT SLOWLY DRIFTS SOUTH, ENCOUNTERING A SUSTAINED COOL AND DRY LOW
LEVEL FLOW ROTATING AROUND HIGH PRESSURE SLIDING ACROSS SOUTHERN
CANADA...WITH AN OFF THE DECK WARM NOSE SUPPLIED BY ELEVATED WARM
AIR ADVECTION ONLY ADDING TO THE COMPLEXITY. IMPRESSIVE SURGE OF
DEEP LAYER ISENTROPIC UPGLIDE TAKES CENTER STAGE TOMORROW AS LOW
PRESSURE BEGINS TO LIFT OUT OF THE SOUTHERN PLAINS. NO DOUBT ABOUT
IT, ABOVE YIELDS ONE COMPLICATED AND RELATIVELY LOW CONFIDENCE
FORECAST TONIGHT AND SATURDAY.
PRIMARY FORECAST CONCERNS:
PRIMARY CONCERNS REMAINS CENTERED ON FREEZING RAIN/SLEET
EVOLUTION, AMOUNTS, AND ATTENDANT IMPACTS/HEADLINE MANAGEMENT.
DETAILS:
ABOUT AS TRICKY OF A FORECAST AS THEY GET, WITH BOTH AN ELEVATED
WARM NOSE AND WITH A MARGINALLY COLD LOW LEVEL THERMAL PROFILE TO
CONTEND WITH. BEST EDUCATED GUESS TO FOLLOW: EXPECT PRECIPITATION
TO CONTINUE TO EXPAND AND BUILD SOUTH INTO UPPER MICHIGAN INTO THE
STRAITS REGION THIS EVENING AS ELEVATED FGEN RESPONSE AND DEEP
MOISTURE CONVERGENCE DOES THE SAME. COOL EAST FLOW WILL ONLY
INTENSIFY WITH TIME, KEEPING TEMPERATURES NEAR OR A TOUCH BELOW
FREEZING TONIGHT FOR AREAS NORTH OF THE BIG BRIDGE. LATEST TRENDS
SUGGESTING WARM NOSE ACROSS EASTERN UPPER MAY NOT BE QUITE AS ROBUST
AS INITIALLY THOUGHT, PERHAPS SUPPORTING A MIX OF FREEZING RAIN AND
SLEET...WITH MORE SLEET THE FURTHER NORTH ONE GOES. STILL, LOOKING
AT UPWARDS OF A QUARTER OF AN INCH OR MORE OF FREEZING RAIN FOR AT
LEAST PARTS OF EASTERN UPPER MICHIGAN BY SUNRISE SATURDAY...
DEFINITELY ENOUGH TO CAUSE SOME SIGNIFICANT IMPACTS...INCLUDING
MINOR TREE DAMAGE AND POWER OUTAGES. COLD AIR BLEEDS SOUTH WITH TIME
TONIGHT, BRINGING FREEZING RAIN CONCERNS INTO THE TIP OF THE MITT
COUNTIES. A BIT LATER START AND A MORE MARGINAL LOW LEVEL THERMAL
PROFILE (LIKELY SOME MODIFICATION FROM LAKE HURON) SHOULD LIMIT
OVERALL ICE ACCUMULATIONS, BUT AGAIN STILL LOOKING AT A TENTH TO
QUARTER OF AN INCH BY SUNRISE SATURDAY. BIGGEST QUESTION IS JUST HOW
FAR SOUTH THE FREEZING LINE DESCENDS...WITH SOME EVIDENCE FOR AT
LEAST SOME ICING IMPACTS ALONG AND NORTH OF M-32 STRETCHING FROM
EASTERN OTSEGO TO WESTERN ALPENA COUNTIES. TENTATIVELY BELIEVE THIS
AREA WILL ONLY SEE MINOR ICE ACCUMULATIONS/IMPACTS...NOT WORTHY OF
ANY HEADLINE TONIGHT. TO TOP ALL THIS OFF, WILL LIKELY SEE SOME
EMBEDDED DEEPER CONVECTION WITHIN THE LARGER RAIN SHIELD...
SUPPORTING SOME ISOLATED TO SCATTERED THUNDERSTORMS. WHILE NOTHING
SEVERE IS EXPECTED, COOL PROFILES COULD RESULT IN SOME SMALLER SIZE
HAIL WITH ANY MORE ORGANIZED UPDRAFTS.
THERMAL GRADIENT AND ATTENDANT PRECIPITATION SLOWLY SAGS SOUTH AND
LIKELY DECREASES IN ORGANIZATION SATURDAY MORNING, WITH LIKELY SOME
REGENERATION LATER IN THE DAY AS ISENTROPIC UPGLIDE AGAIN INCREASES.
THAT SOUTHWARD SAGGING THERMAL GRADIENT SUPPORTS NEAR TO SUB-
FREEZING TEMPERATURES EXPANDING ACROSS A GOOD PORTION OF INTERIOR
NORTH CENTRAL AND NORTHEAST LOWER MICHIGAN. FREEZING RAIN APPEARS
LIKELY, MORE SO ON ELEVATED SURFACES AS SOLAR INSOLATION INCREASES
THROUGH THE DAY. WOULD AGAIN EXPECT SOME INCREASED IMPACTS,
ESPECIALLY AS WE HEAD TOWARD EVENING (WITH MORE ICE EXPECTED
SATURDAY NIGHT). WINTER STORM WATCHES HAVE BEEN ISSUED TO ACCOUNT
FOR THIS SIGNIFICANT ICE POTENTIAL.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
ISSUED AT 251 PM EDT FRI MAR 28 2025
PATTERN SYNOPSIS:
CURRENT STATIONARY BOUNDARY SET UP ACROSS MICHIGAN'S UPPER PENINSULA
WILL REMAIN OVER THE NORTHWOODS UNTIL THE BEGINNING OF THE LONG TERM
PERIOD. AT THE SAME, SURFACE LEVEL LOW PRESSURE WILL BEGIN TO
DEVELOP AND MAKE ITS WAY TO THE MIDWEST THIS WEEKEND. WITH
TEMPERATURES ONCE AGAIN NEAR FREEZING AT THE SURFACE AND WARMER
AIR ALOFT, ANOTHER ROUND OF FREEZING RAIN SATURDAY NIGHT INTO
SUNDAY MORNING. WARM AIR ADVECTION ASSOCIATED ON THE WARM SIDE
OF THE SYSTEM WILL EVENTUALLY RETURN SHOWERS TO THE ENTIRE CWA
THIS SUNDAY. CONDITIONS QUICKLY OVERHAUL HOWEVER AS COLD AIR ON
THE BACKSIDE OF THE LOW WILL SWITCH PRECIPITATION FROM RAIN TO A
WINTRY MIX/SNOW BEFORE DEPARTING TO THE EAST COAST.
QUIET WEATHER THANKFULLY RETURNS THIS TUESDAY AS LONGWAVE TROUGHING
OVER CANADA PUSHES COOL AND DRY CONTINENTAL AIR INTO THE REGION. THE
MIDLEVEL PATTERN UPSTREAM REMAINS PRETTY ACTIVE HOWEVER AS ANOTHER
WAVE OF ENERGY DEVELOPS OVER THE ROCKIES AND EJECTS ITSELF INTO THE
GREAT LAKES. "BEAUTIFUL" SPRING SURFACE AND LOW LEVEL TEMPERATURES
HOVERING AROUND FREEZING WILL CONTINUE CHANCES OF MULTIPLE PRECIP
TYPES AROUND THE WEDNESDAY/THURSDAY TIMES FRAME. AT THIS TIME, MORE
RAIN FAVORS AREAS SOUTH OF THE BRIDGE WHILE SLEET/SNOW STAYS ALONG
EASTERN UPPER, BUT THAT IS LIKELY TO CHANGE AS FUTURE GUIDANCE
DETERMINES THE TRACK OF LOW PRESSURE.
PRIMARY FORECAST CONCERNS:
DESCRIBING THIS SYSTEM AS MESSY WOULD BE AN UNDERSTATEMENT DUE TO
THE RAPIDLY CHANGING AND VARIABLE WEATHER TYPES ACROSS THE CWA THIS
WEEKEND. BIGGEST IMPACTS FOR THE ENTIRETY OF THE FORECAST PERIOD ARE
AT THE BEGINNING AS THERMAL PROFILES INDICATE FREEZING RAIN AND
CONTINUE OVERNIGHT INTO SUNDAY MORNING. FORECAST REMAINS EXTREMELY
TRICKY AS TEMPERATURES ACROSS THE CWA ARE AT OR BELOW FREEZING.
AREAS LIKELY TO SEE ACCUMULATING ICE WILL BE EAST OF I-75 AND NORTH
OF M-72 WHERE OVERNIGHT LOWS DROP INTO THE UPPER 20S WHILE THE LOW
LEVEL JET KEEPS H8 WARM ENOUGH TO MELT ANY FALLING PRECIP.
ACCUMULATIONS AT THIS TIME FOR THESE AREAS ARE LIKELY TO BE AROUND A
QUARTER INCH BY SUNDAY MORNING, BUT FAVORABLE AREAS SUCH AS ELEVATED
TERRAIN MAY SEE EVEN MORE. OBVIOUSLY ROADWAYS ARE A CONCERN WITH ICE
BUILD UP, BUT 20-30 MPH GUSTS COMBINED WITH THE ADDED WEIGHT OF
LIQUID ON BRANCHES/POWERLINES COULD LEAD TO POWER OUTAGES ACROSS THE
REGION. AS FOR AREAS OUTSIDE OF FAVORABLE ICING... SOME SMALL
ACCUMULATIONS OF A GLAZING OF ICE TO A TENTH OR SO REMAINS POSSIBLE,
BUT LUCKILY SURFACE TEMPS REMAIN WARM ENOUGH TO LIMIT BUILD UP FOR
THE MORE POPULATED AREAS NEAR TRAVERSE BAY.
WARM AIR ADVECTION QUICKLY SURGES TEMPERATURES INTO THE 40S AND 50S
THIS SUNDAY, EVENTUALLY (BREIFLY) TRANSITIONING ALL AREAS TO
RAINFALL. INSTABILITY ALOFT WILL LEAD TO SOME CONVECTIVE DRIVEN
SHOWERS AND THUNDERSTORMS AS THE WARM SECTOR BUILDS ACROSS THE
REGION. A COUPLE STRONGER STORMS NEAR THE SOUTHERNMOST PARTS OF THE
CWA COULD PERHAPS PRODUCE SEVERE HAIL, BUT OVERALL THIS PERIOD
SHOULD PROVIDE A BRIEF LULL BEFORE COLD AIR BUILD ON THE BACKSIDE OF
THE SURFACE LOW AND RETURNS A FINAL ROUND ON RAIN TRANSITIONING TO
SNOW. SNOWFALL AMOUNTS WILL BE PRETTY MINOR ON MONDAY, WITH ONLY A
TENTH OR SO EXPECTED FOR PARTS OF NORTHERN LOWER AND EASTERN UPPER,
BUT RAPIDLY FREEZING TEMPERATURES COULD ONCE AGAIN RESULT IN ICY
ROADWAYS AND POOR DRIVING CONDITIONS FOR THE MONDAY COMMUTE.
COLD POLAR AIR FROM THE NORTH WILL UNFORTUNATELY KEEP TEMPERATURES
COOLER THAN NORMAL WITH HIGHS IN THE 30S AND 40S NEXT WEEK. ANOTHER
CHANCE OF PRECIPITATION RETURNS LATER NEXT WEEK AS A SHORTWAVE
TROUGH DEEPENS AND TRACKS ACROSS THE GREAT LAKES AROUND THE
WEDNESDAY/THURSDAY TIMEFRAME.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 103 AM EDT SAT MAR 29 2025
WARM FRONT HAS STALLED OVER CENTRAL WISCONSIN AND CENTRAL LOWER
MICHIGAN EARLY THIS MORNING...AND IS SLATED TO VERY SLOWLY SINK
SOUTHWARD TOWARD THE SOUTHERN BORDERS OF THESE TWO STATE TODAY
INTO TONIGHT. WAVES OF SHOWERS AND SOME EMBEDDED THUNDERSTORMS
WILL CONTINUE TO IMPACT OUR AREA OVERNIGHT...WITH LOCATIONS
ALONG AND NORTH OF M-32 EXPERIENCING SOME FREEZING
RAIN/SLEET/SNOW. WIDESPREAD MIXED PRECIP WILL CONTINUE TO IMPACT
MUCH OF NORTHERN LOWER MICHIGAN THRU THE DAY ON SATURDAY...WITH
THIS PRECIP THEN SPREADING NORTHWARD INTO EASTERN UPPER
MICHIGAN AGAIN SATURDAY NIGHT. PREVAILING CONDITIONS WILL REMAIN
IFR FOR THE NEXT 24 HOURS. SURFACE WINDS WILL REMAIN FROM THE NE
AT 15 TO 25 KTS.
APX WATCHES/WARNINGS/ADVISORIES
MI...ICE STORM WARNING UNTIL 11 AM EDT THIS MORNING FOR MIZ016>018-
086>088-095>097.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT THIS MORNING FOR
MIZ022>024.
WINTER STORM WATCH FROM 8 AM EDT THIS MORNING THROUGH SUNDAY
MORNING FOR MIZ022>024-028>030.
WINTER WEATHER ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
MIZ098.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LHZ345>349.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-
341-342-344>346.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ321-
322.
UPDATE...JZ
SHORT TERM...MSB
LONG TERM...SJC
AVIATION...MLR
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