Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 181433
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1033 AM EDT THU SEP 18 2014

.SYNOPSIS...
ISSUED AT 419 AM EDT THU SEP 18 2014

COOL CANADIAN HIGH PRESSURE BUILDS IN TODAY THEN PUSHES OFF TO OUR
EAST FRIDAY. SO AFTER A COOLER DAY TODAY...MODERATING TEMPERATURES
ARE EXPECTED FRIDAY INTO SATURDAY DUE TO A WARMER SOUTHWESTERLY WIND
FLOW. MEANWHILE...LOW PRESSURE MOVING THROUGH THE GREAT LAKES REGION
WILL BRING SHOWERS AND CHANCES FOR THUNDERSTORMS BEGINNING FRIDAY
NIGHT...AND CONTINUING THROUGH SATURDAY EVENING...WITH SHOWERS
POSSIBLY LINGERING INTO SUNDAY AS WELL.

&&

.UPDATE...
ISSUED AT 1032 AM EDT THU SEP 18 2014

LARGE CENTER OF HIGH PRESSURE HAS SETTLED ACROSS THE FAR NRN GREAT
LAKES INTO ONTARIO THIS MORNING. SFC COLD FRONT NOW SUPPRESSED
WELL SOUTH OF THE REGION. A FAIRLY SHALLOW COLD AIRMASS SITS
ACROSS NORTHERN MICHIGAN PER THIS MORNINGS APX/GRB SOUNDINGS. BUT
AS ANTICIPATED...FAIRLY WIDESPREAD STRATUS MANAGED TO EXPAND
ACROSS MUCH OF MICHIGAN AND WISCONSIN UNDER THE STOUT INVERSION
OVERNIGHT. ALSO...WITH TEMPS RUNNING JUST ABOVE 0C AT THE BOTTOM
OF THE INVERSION...HAVE QUITE A BIT OF LAKE CLOUD BANDS ON HURON
AND MICHIGAN AS WELL...AND JUST A TOUCH OF DRIZZLE ACROSS NRN
LOWER MICHIGAN. EASTERN UPPER DID CLEAR OUT FINALLY EARLY THIS
MORNING...BUT TO LATE TO GET WIDESPREAD FROST.

TODAY...MAINLY SUNNY SKIES IN EASTERN UPPER WITH A NE-E FLOW
TRAJECTORY OFF ONTARIO. BUT NRN LOWER MICHIGAN...STUCK WITH CLOUDS
FOR AWHILE. NE-E LOW LEVEL FLOW...MOISTURE/HEAT FLUX OFF HURON AND
DAYTIME HEATING WILL CONSPIRE TO KEEP CLOUDY SKIES INTACT FOR MUCH
OF THE CWA THROUGH AT LEAST EARLY OR MID AFTERNOON. BUT I REMAIN
OPTIMISTIC THAT WEAKENING LOW LEVEL FLOW THIS AFTERNOON COMBINED
WITH HEATING AND MIXING SHOULD EVENTUALLY ERODE AWAY THE LOW
CLOUDS BY LATE IN THE DAY. HAVE TWEAKED SKY FORECASTS JUST A BIT
TO KEEP CLOUDY SKIES AROUND LONGER.

TONIGHT...HIGH PRESSURE CENTER SLIDES ON TO THE EAST WITH LOW
LEVEL FLOW VEERING AROUND TO THE SOUTH BY FRIDAY MORNING. AM
CONCERNED THAT WHATEVER LOW LEVEL MOISTURE REMAINS OUT THERE WILL
SIMPLY GET RECYCLED BACK TO THE NORTH AND BRING ANOTHER BATCH OF
EXPANDING STRATUS UP THROUGH NRN LOWER/EASTERN UPPER MICHIGAN.
CERTAINLY THAT TIME OF YEAR FOR THAT SORT OF NUISANCE STUFF TO
HAPPEN AND NAM12 925 RH FORECASTS CERTAINLY SUPPORT THAT IDEA. OF
COURSE THAT HAS BIG TEMPERATURE AND FROST IMPLICATIONS. WILL
PONDER THESE ISSUES FOR THE AFTERNOON FORECAST.

UPDATE ISSUED AT 653 AM EDT THU SEP 18 2014

HAD TO ADD PATCHY DRIZZLE FOR NORTH CENTRAL/NORTHEAST LOWER FOR
THE NEXT FEW HOURS SINCE WE`VE BEEN GETTING SOME BITS OF PRECIP
RECENTLY. NORTHEAST UPSLOPE FLOW INTO THE HILLTOPS PROBABLY NOT
HURTING THE CAUSE. NO OTHER CHANGES.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 419 AM EDT THU SEP 18 2014

...CLOUDS SLOW TO CLEAR NORTHERN LOWER TODAY/FROST POSSIBLE
TONIGHT...

HIGH IMPACT WEATHER POTENTIAL: FROST POTENTIAL EARLY FRIDAY
MORNING...ESPECIALLY ACROSS INTERIOR NORTH CENTRAL/NORTHEAST LOWER
MICHIGAN.

PATTERN SYNOPSIS/FORECAST: EARLY MORNING SURFACE ANALYSIS SHOWS AN
EAST-WEST ORIENTED COLD FRONT CUTTING ACROSS NORTHERN LOWER MICHIGAN
AND EXTENDING BACK INTO NORTHERN WISCONSIN/CENTRAL MINNESOTA/NORTH
DAKOTA...WITH COOL CANADIAN HIGH PRESSURE BUILDING SOUTH ACROSS LAKE
SUPERIOR/UPPER MICHIGAN.  BENEATH THIS SURFACE HIGH...AFTERNOON HIGH
TEMPERATURES WERE IN THE 40S ACROSS NORTHERN ONTARIO BEHIND THE
FRONT AND 00Z YPL 850MB TEMPERATURE WAS DOWN TO -4C.  SHORT WAVE
TROUGHING WAS MOVING AWAY FROM THE UPPER GREAT LAKES AND INTO
QUEBEC...AND THOUGH WATER VAPOR IMAGERY SHOWS ANOTHER SMALL
VORTICITY CENTER CROSSING LAKE SUPERIOR IN NORTHWEST FLOW ALOFT...
POCKET OF DRY AIR SPREADING ACROSS LAKE SUPERIOR PREVENTING THIS
FEATURE FROM HAVING MUCH IMPACT.  LOW STRATUS WAS SPREADING SOUTH
ACROSS THE FORECAST AREA BEHIND THE COLD FRONT...WITH SOME THINNING
OF CLOUD COVER EAST OF LAKE SUPERIOR.  PROBABLY SOME LAKE MICHIGAN/
HURON COMPONENT TO CLOUD COVER SETTING UP WITH 925MB TEMPERATURES
AROUND 4-6C AND WATER TEMPERATURES RUNNING AROUND 16C ON LAKE
MICHIGAN AND 12-14C NORTHERN LAKE HURON.

COLD FRONT WILLS SINK SOUTH INTO SOUTHERN LOWER MICHIGAN THIS
MORNING...WHILE CENTRAL CANADIAN SURFACE HIGH WILL SHIFT EAST TODAY
AND MOVE INTO QUEBEC BY THIS EVENING.

PRIMARY FORECAST CONCERNS: CLOUDS TODAY...AND LOW TEMPERATURES AND
RESULTANT FROST POTENTIAL TONIGHT.

TODAY...CLOUDS HAVE CERTAINLY BEEN MORE PERSISTENT EARLY THIS
MORNING ESPECIALLY ACROSS EASTERN UPPER WHERE CLEARING IS KNOCKING
ON THE DOOR OF THE ST. MARY`S RIVER.  BUT THIS ISN`T BODING WELL FOR
FROST POTENTIAL EARLY THIS MORNING...THOUGH STILL EXPECT SKIES TO
IMPROVE OVER THE NEXT SEVERAL HOURS ACROSS EASTERN UPPER.  WILL
PROBABLY CAN THE FROST ADVISORY FOR CHIPPEWA/MACKINAC COUNTIES WITH
08Z FORECAST ISSUANCE.  BELOW THE BRIDGE WILL BE A LITTLE MORE SOUR
ON THE PROSPECTS FOR MUCH SUN TO START THE DAY...WITH CLOUD COVER
BEING REINFORCED BY NORTHEAST BOUNDARY LAYER FLOW OFF LAKE HURON.
CLOUDS WILL PROBABLY MIX INTO A HIGHER STRATOCUMULUS DECK DURING THE
LATE MORNING/EARLY AFTERNOON HOURS...AND PROBABLY BECOME MORE
SCATTERED OVER NORTHWEST LOWER WHILE COVERAGE REMAINS MORE
SUBSTANTIAL OVER NORTHEAST LOWER PARTICULARLY SOUTH OF M-32.  HIGHS
TODAY WILL BE COOLER THAN YESTERDAY...MAINLY 50S/AROUND 60 WEST OF
THE M-37 CORRIDOR.

TONIGHT...LOOKS LIKE SKIES TONIGHT WILL BE MAINLY CLEAR-PARTLY
CLOUDY.  DEPENDING ON DEGREE OF MIXING THIS AFTERNOON THERE COULD BE
SOME RESIDUAL LOW LEVEL MOISTURE THAT MAY ALLOW FOR SOME STRATUS (OR
FOG PATCHES) TO DEVELOP ACROSS NORTHERN LOWER.  THERE WILL ALSO BE A
STRONGER GRADIENT THAT BEGINS TO DEVELOP OVERNIGHT...SO MAY SEE A
LITTLE BREEZE POP UP ACROSS EASTERN UPPER/NORTHWEST LOWER.  SO JUST
A COUPLE OF STICKING POINTS TO TONIGHT`S LOW TEMPERATURE FORECAST.
ON THE PLUS SIDE WE WILL HAVE A COOL START TO THE EVENING GIVEN
BELOW NORMAL HIGH TEMPERATURES EXPECTED THIS AFTERNOON...AND AS
LONG AS THERE IS A LACK OF CLOUD COVER THERE SHOULD BE A PRETTY
GOOD FROST THREAT FOR INTERIOR NORTHERN LOWER.  POTENTIAL FOR
INCREASING WINDS RAISES SOME QUESTIONS FOR EASTERN UPPER FROST
POSSIBILITIES...BUT WILL CONTINUE TO HIGHLIGHT FROST THREAT FOR
NORTHERN LOWER.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 419 AM EDT THU SEP 18 2014

...MODERATING TEMPS INTO THE WEEKEND THEN COOLING OFF AGAIN...

HIGH IMPACT WEATHER POSSIBILITIES: CHANCE FOR SEVERE STORMS SATURDAY
INTO SATURDAY EVENING THEN FROST POTENTIAL EARLY NEXT WEEK.

THE UPPER LEVEL FLOW FLATTENS OUT ACROSS THE GREAT LAKES FRIDAY INTO
SATURDAY BEFORE RENEWED RIDGING OUT WEST INDUCES MORE TROUGHING
AGAIN FOR EARLY NEXT WEEK FOLLOWED BY RISING HEIGHTS BY MID WEEK
(IN OTHER WORDS GET READY FOR A ROLLER COASTER RIDE). THIS SCENARIO
IS EXPECTED TO LEAD TO MODERATING TEMPERATURES FOR FRIDAY INTO THE
WEEKEND BEFORE RETREATING BACK TO BELOW AVERAGE LEVELS AGAIN FOR THE
BEGINNING OF NEXT WEEK FOLLOWED BY MODERATING TEMPERATURES. IN
ADDITION...SHOWERS AND POSSIBLY THUNDERSTORM CHANCES INCREASE MAINLY
FROM FRIDAY NIGHT INTO SATURDAY EVENING. THE MAIN LONG TERM FORECAST
CONCERNS REVOLVE AROUND POPS FOR FRIDAY NIGHT ALL THE WAY INTO
MONDAY ALONG WITH THE POTENTIAL FOR SEVERE STORMS AND/OR HEAVY
RAINFALL SATURDAY INTO SATURDAY EVENING.

HIGH PRESSURE SAILS OFF TO OUR EAST FRIDAY BUT HOLDS ON WHAT LOOKS
LIKE LONG ENOUGH TO KEEP ANY SHOWERS AT BAY FOR MUCH IF NOT ALL OF
THE DAY. MEANWHILE...LOW PRESSURE DEVELOPS ACROSS THE WESTERN GREAT
LAKES FRIDAY NIGHT AND MOVES ACROSS THE REGION SATURDAY LEADING TO A
"WARMER" AND MUCH MORE MOIST SOUTHERLY FLOW. THIS SYSTEM WILL LIKELY
BRING SHOWERS AND CHANCES FOR THUNDERSTORMS FRIDAY NIGHT THROUGH
SATURDAY EVENING. MODELS CONTINUE TO ADVERTISE STRONG LOW/MID LEVEL
WIND FIELDS WITH 0-6KM BULK SHEARS VALUES BETWEEN 40 AND 50 KNOTS.
HOWEVER...THERE ARE MANY UNANSWERED QUESTIONS OVER THE AMOUNT OF
INSTABILITY DUE TO EXPECTED EXTENSIVE CLOUD COVER. HOWEVER...IF WE
CAN MIX OUT...A DAMAGING WIND THREAT DEFINITELY EXISTS...MAINLY FOR
SATURDAY AFTERNOON AND EVENING. IT STILL LOOKS LIKE HEAVY DOWNPOURS
ARE POSSIBLE AS STRONG THETA-E RIDGING PUSHES PRECIPITABLE WATER
VALUES UPWARDS OF BETWEEN 1.50 AND 1.75 INCHES ON SATURDAY...AS
DEVELOPING LOW PRESSURE TRIES TO TAP INTO SOME OF THE REMNANT
TROPICAL MOISTURE FROM THE SOUTHWEST. ANOTHER NORTHERN STREAM TROUGH
THEN DROPS IN FOR SUNDAY INTO MONDAY...PERHAPS EVEN PRODUCING A FEW
LAKE EFFECT SHOWERS. HOWEVER...EXTENDED MODELS CONTINUE TO VARY ON
JUST HOW DEEP/COLD THIS SYSTEM WILL BE WITH LATEST GUIDANCE ON THE
MORE MELLOW SIDE (NOT AS COLD). EITHER WAY...COOL AIR LOOKS TO BE
SLOW TO LIFT OUT THROUGH THE MIDDLE OF NEXT WEEK DESPITE RENEWED
RISING HEIGHTS ALOFT. THERE IS STILL POTENTIAL FOR FROST FORMATION
FOR BOTH MONDAY AND TUESDAY NIGHTS (MORE ON THAT MUCH LATER).

FORECAST HIGH TEMPERATURES IN THE MIDDLE TO UPPER 60S FRIDAY
FOLLOWED BY THE LIKELY WARMER MIDDLE 60S TO MIDDLE 70S SATURDAY
(ALTHOUGH THIS IS A TOUGH CALL AS IT WILL BE VERY WARM ALOFT BUT
EXPECTED CLOUD COVER WILL LIKELY KEEP TEMPERATURES FROM GOING TOO
CRAZY). HIGHS SUNDAY RANGING FROM THE COOLER UPPER 50S TO UPPER 60S
THEN FALLING BACK INTO THE MIDDLE 50S TO LOWER 60S FOR BOTH MONDAY
AND TUESDAY. HIGHS WEDNESDAY A TAD MILDER WITH THE LOWER AND MIDDLE
60S EXPECTED. LOWS RANGING FROM THE MILDER MIDDLE 50S TO NEAR 60
FRIDAY NIGHT THEN THE STILL MILD LOWER AND MIDDLE 50S SATURDAY
NIGHT/ THIS WILL BE FOLLOWED BY UPPER 30S TO MIDDLE 40S SUNDAY NIGHT
THEN THE CHILLY MIDDLE 30S TO THE LOWER 40S FOR BOTH MONDAY AND
TUESDAY NIGHTS (PERHAPS EVEN PRODUCING SOME FROST).

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 653 AM EDT THU SEP 18 2014

MVFR CEILINGS THIS MORNING WILL BE SLOW TO LIFT...SHOULD IMPROVE
TOWARD MIDDAY AT PLN/TVC/MBL BUT CEILINGS WILL LIKELY PERSIST
UNTIL LATE AFTERNOON AT APN.


&&

.MARINE...
ISSUED AT 419 AM EDT THU SEP 18 2014

WEAKENING GRADIENT WITH HIGH PRESSURE BUILDING IN FROM THE NORTHWEST
WILL KEEP WINDS LIGHTER FROM THE NORTHEAST/EAST TODAY...WILL NEED TO
CHECK ON RESIDUAL WAVE ACTION ON LAKE MICHIGAN TO SEE IF SMALL CRAFT
ADVISORY WILL NEED TO BE MAINTAINED THIS MORNING.  OTHERWISE WINDS
ARE EXPECTED TO SWING AROUND TO THE SOUTH/SOUTHEAST TONIGHT AS HIGH
PUSHES EAST OF THE UPPER GREAT LAKES.  BUT WINDS ARE EXPECTED TO
PICK UP TONIGHT ESPECIALLY ON LAKE MICHIGAN...AND MAY NEED ANOTHER
ROUND OF SMALL CRAFT ADVISORIES HEADING INTO FRIDAY.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...ADAM
SYNOPSIS...AJS
SHORT TERM...JPB
LONG TERM...AJS
MARINE...JPB





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