Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 191052
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
652 AM EDT FRI SEP 19 2014

.SYNOPSIS...
ISSUED AT 420 AM EDT FRI SEP 19 2014

MODERATING TEMPERATURES ARE EXPECTED TODAY THROUGH SATURDAY AS
SOUTHERLY WINDS DEVELOP AHEAD OF AN APPROACHING COLD FRONT. THIS
FRONT WILL ALSO BRING INCREASING RAIN CHANCES...WITH THE THREAT FOR
SHOWERS AND THUNDERSTORMS BEGINNING THIS EVENING...WITH PERIODIC
SHOWERS AND THUNDERSTORMS CONTINUING SATURDAY. ADDITIONAL UPPER
LEVEL DISTURBANCES BEHIND THIS FRONT WILL KEEP THE THREAT FOR MORE
SHOWERS GOING THROUGH SUNDAY. QUIETER AND INCREASINGLY MILD
CONDITIONS ARE EXPECTED HEADING THROUGH NEXT WORK WEEK.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 420 AM EDT FRI SEP 19 2014

...MOSTLY DRY AND MILD TODAY/SHOWERS AND THUNDERSTORMS TONIGHT...

HIGH IMPACT WEATHER POTENTIAL: GALE FORCE WINDS ON LAKE MICHIGAN BY
TONIGHT.  THUNDERSTORMS WHICH COULD BE ON THE STRONG SIDE OVERNIGHT
WITH A POSSIBLE HAIL THREAT.

PATTERN SYNOPSIS/FORECAST: EARLY MORNING SURFACE ANALYSIS SHOWS
1027MB HIGH OVER WESTERN QUEBEC...WITH AN ELONGATED AREA OF LOW
PRESSURE OVER CENTRAL CANADA.  1000MB SURFACE LOW CENTER WITHIN THIS
BROADER AREA OF LOW PRESSURE ALONG THE SASKATCHEWAN/MANITOBA BORDER
WITH A FRONTAL (WARM) BOUNDARY EXTENDING SOUTHEAST ACROSS THE UPPER
MIDWEST/MID MISSISSIPPI VALLEY.  PRETTY STRONG TEMPERATURE CONTRAST
BETWEEN THESE TWO FEATURES...WITH TEMPERATURES IN THE UPPER 20S
ACROSS NORTHEAST ONTARIO...WITH 65-70 DEGREE READINGS OVER SOUTHWEST
MANITOBA.  LOW AMPLITUDE SHORT WAVE RIDGE AXIS WAS MOVING INTO THE
UPPER GREAT LAKES AS MAIN WESTERLIES HAVE BECOME A LITTLE FLATTER
OVER THE PAST COUPLE OF DAYS.  POSITIVE TILT ELONGATED POTENTIAL
VORTICITY ANOMALY STRETCHES FROM SOUTHERN SASKATCHEWAN ACROSS THE
GREAT BASIN TO OFF THE CENTRAL/SOUTHERN CALIFORNIA COAST.  LOW/MID
LEVEL WARM ADVECTION IS UNDERWAY ACROSS THE UPPER LAKES...THOUGH
STILL PRETTY DRY ACROSS THE FORECAST AREA...00Z APX SOUNDING
PRECIPITABLE WATER UNDER 0.30 INCH (LESS THAN 40 PERCENT OF
NORMAL).  THERE IS SOME RESIDUAL LOW LEVEL MOISTURE LEFTOVER FROM
EARLIER CLOUD COVER...AND IS MANIFESTING ITSELF AS AN EXPANDING AREA
OF STRATUS ACROSS INTERIOR NORTHERN LOWER.  SOME SCATTERED HIGH
BASED STRATOCUMULUS ASSOCIATED WITH ABOVE MENTIONED WARM ADVECTION
PATTERN ALSO FOUND ACROSS LAKE MICHIGAN/NORTHWEST LOWER.

FLAT SHORT WAVE RIDGE EXPECTED TO SLIDE ACROSS MICHIGAN THIS MORNING
WHILE UPSTREAM SHORT WAVE TROUGH/PV ANOMALY TRACKS EAST INTO THE
NORTHERN PLAINS.  AS THIS OCCURS PRESSURES WILL FALL ACROSS MICHIGAN
TODAY WITH AN INCREASING SOUTHERLY GRADIENT WIND DEVELOPING AS
SYNOPTIC LOW LEVEL JET IMPINGES UPON NORTHERN MICHIGAN BY LATE IN
THE DAY.  INCREASING RETURN FLOW ALSO DRAWS MOISTURE UP INTO THE
FORECAST AREA AS WELL TONIGHT (PRECIPITABLE WATER VALUES APPROACHING
1.25 INCH ALREADY IN PLACE ACROSS THE DAKOTAS/SOUTHERN MANITOBA).

PRIMARY FORECAST CONCERNS: EARLY ONGOING CLOUD COVER AND WINDS FOR
TODAY...AND RAIN CHANCES TONIGHT GIVEN COMBINATION OF GOOD MOISTURE
INFLOW/WARM ADVECTION AND HEIGHT FALLS WITH ADVANCING SHORT WAVE
TROUGH.

TODAY...CURRENT THINKING WITH RESPECT TO CLOUD COVER IS THAT CURRENT
LOW CLOUDS OVER NORTHERN LOWER WILL TEND TO MIX OUT WITH TIME THIS
MORNING...BUT WARM ADVECTION CLOUDS MAY BE MORE PROBLEMATIC ACROSS
EASTERN UPPER.  00Z GRB/DTX SOUNDINGS SHOW HIGHER MIXING RATIOS
GETTING PULLED TOWARD UPPER MICHIGAN AND INTERACTING WITH A
LOCALIZED TIGHT THERMAL GRADIENT WHICH MAY END UP GENERATING  MORE
CLOUD COVER ABOVE THE BRIDGE FOR A GOOD CHUNK OF TODAY.  COULD ALSO
SQUEEZE OUT SOME DRIZZLE AS WELL THIS MORNING (ERY VISIBILITY
DROPPING TO 7 MILES LOOKS LIKE AN AUSPICIOUS SIGN).  MID CLOUDS WILL
ALSO BE SPREADING INTO THE FORECAST AREA FROM THE WEST DURING THE
MID AND LATE AFTERNOON HOURS AS DEEPER MOISTURE ADVANCES TOWARD
NORTHERN MICHIGAN.  OUTSIDE OF ANY MORNING DRIZZLE FOR EASTERN UPPER
SHOULD I DECIDE TO THROW THAT INTO THE MIX...WILL HOLD OFF ON RAIN
CHANCES UNTIL THIS EVENING.  WINDS WILL CONTINUE TO PICK UP
TODAY...GUSTING 20-30 MPH THIS AFTERNOON WITH STRONGER GUSTS OVER
EASTERN UPPER/NORTHWEST LOWER.

TONIGHT...THINK THE INITIAL PUSH OF PRECIPITATION WILL BE ACROSS
EASTERN UPPER AND STRAITS REGION THIS EVENING...BUT INCREASING LOW
LEVEL THETA-E ADVECTION AND ADVECTION OF STEEPER MID LEVEL LAPSE
RATES WILL LIKELY SUPPORT THUNDERSTORM DEVELOPMENT ON THE OTHER SIDE
OF LAKE MICHIGAN DURING THE MID TO LATE EVENING AND SPREAD INTO
NORTHERN LOWER AROUND OR SHORTLY AFTER MIDNIGHT. ON THE PLUS SIDE
WITH REGARD TO FRIDAY NIGHT FOOTBALL GAMES...LOOKS LIKE MOST GAMES
SHOULD END BEFORE ANY REAL ISSUES OCCUR.  PLENTY OF WIND ENERGY AND
SHEAR ALOFT TO SUPPORT ORGANIZED UPDRAFTS WITH CONVECTION...AND
WHILE BOUNDARY LAYER STABILIZATION WILL LIMIT WIND DAMAGE
POTENTIAL HAIL MAY BE A THREAT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 420 AM EDT FRI SEP 19 2014

...RATHER WET LOOKING WEEKEND...

HIGH IMPACT WEATHER POTENTIAL: THUNDERSTORM CONCERNS SATURDAY. NOT
MUCH THEREAFTER.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: CURRENT AMPLIFIED NOAM
PATTERN SET TO GET A RATHER SIGNIFICANT BOOST...COURTESY OF STRONG
UPPER JET SLATED TO DIVE INTO AND THROUGH THE GREAT LAKES THIS
WEEKEND. SAID JET ALREADY FULLY MATURE BACK ACROSS THE NORTH
PACIFIC...WITH NOSE OF 140+ KNOT H25 JET ALREADY ENTERING ABOVE THE
SHORE OF BRITISH COLUMBIA. ADDITIONAL JET ENERGY DIGGING ON ITS
BACKSIDE...AND THESE WILL WORK IN TANDEM TO INITIATE RAPID WESTERN
NOAM RIDGE BUILDING AND SUBSEQUENT DOWNSTREAM TROUGH DEEPENING INTO
OUR NECK OF THE WOODS. THIS CHANGE WILL NOT BE A QUIET ONE...WITH
PRE-TROUGH MOISTURE ADVECTION RIPENING AN ATMOSPHERE FOR MID LEVEL
DYNAMICS AND ATTENDANT COLD FRONT TO WORK OVER. SHOWERS...WITH
EMBEDDED STORMS A RATHER SAFE BET SATURDAY ALONG LEAD CHARGING COLD
FRONT...WITH ADDITIONAL MID LEVEL IMPULSES POTENTIALLY KEEPING
CONDITIONS RATHER UNSETTLED RIGHT INTO SUNDAY. PACIFIC PATTERN LOOKS
TO BECOME INCREASINGLY AGITATED HEADING THROUGH NEXT WEEK...SETTING
UP THE POTENTIAL FOR A RATHER SIGNIFICANT PATTERN CHANGE AS DEEP
TROUGHING DEVELOPS INTO WESTERN NOAM...FORCING A RAPID NORTHWARD
RETREAT OF POLAR JET INTO CENTRAL CANADA. IF THIS OCCURS...THIS
WOULD SET THE STAGE FOR A MILDER AND MUCH QUIETER WEATHER REGIME
HEADING INTO THE LATTER PORTIONS OF THIS FORECAST...AND LIKELY WELL
BEYOND. ONLY TIME WILL TELL OF COURSE.

PRIMARY FORECAST CHALLENGES/CONCERNS: ALMOST ALL EARLY IN THE
PERIOD...MOSTLY CENTERED ON SPATIAL AND TEMPORAL RESOLUTION OF
WEEKEND SHOWERS. THUNDERSTORM POTENTIAL AND INTENSITY WILL ALSO NEED
TO BE ADDRESSED.

DETAILS: AS MENTIONED EARLIER...PLENTY COMING TOGETHER TO BRING A
BOUT OF WET WEATHER THIS WEEKEND. STRONG LOW LEVEL JET FRIDAY NIGHT
WILL SUPPLY THE MOISTURE...WITH PWAT VALUES BY SUNRISE SATURDAY
ALREADY UP NEAR AN INCH AND A HALF (OVER 2 STANDARD DEVIATIONS ABOVE
NORMAL). LOW LEVEL JET ITSELF WILL BE EXITING STAGE RIGHT RATHER
QUICKLY SATURDAY MORNING...WITH BEST FORCED CONVERGENCE FROM SUCH
DOING THE SAME. UPPER JET DYNAMICS INITIALLY FOCUSED TO OUR
WEST...AS IS BEST SURFACE FORCING ALONG APPROACHING FRONT. KINDA
ENVISION INITIAL ROUND OF SHOWERS/PERHAPS WITH ELEVATED
STORMS/PASSING OFF TO OUR EAST...POTENTIALLY NOT LEAVING MUCH UNTIL
BETTER FORCING ARRIVES DURING THE AFTERNOON. UPPER JET FORCING AND
MID LEVEL SUPPORT ALONE SHOULD BE ENOUGH TO GENERATE ADDITIONAL
ACTIVITY DURING THE AFTERNOON. NOT REALLY CONFIDENT ABOUT SURFACED
BASED CONVECTIVE POTENTIAL GIVING WHAT LOOKS TO BE PLENTY OF CLOUD
COVER/LIMITED INSOLATION. DEFINITELY NEED TO MONITOR... HOWEVER...
WITH NEARLY UNIDIRECTIONAL VERTICAL WIND PROFILES SUPPORTING IN
EXCESS OF 50 KNOTS OF 0-6KM SHEAR. WIND SUPPORT IS DEFINITELY THERE
FOR A SEVERE THUNDERSTORM/DAMAGING WIND THREAT. INSTABILITY WILL
DICTATE....WITH CURRENT INDICATIONS BEST POTENTIAL FOR SEVERE
THUNDERSTORM SUPPORTING DESTABILIZATION REMAINING OFF TO OUR SOUTH
(LATEST CIPS IMPACT GUIDANCE CONCURS). DEFINITELY NOT OUT OF THE
WOODS JUST YET...AND WILL CONTINUE TO USE OUR HAZARDOUS WEATHER
PRODUCTS AS AVENUES TO EXPRESS THIS CONCERN.

FRONT SLIDES THROUGH THE REGION SATURDAY EVENING...BUT DOES NOT END
THE RAIN THREAT AS ADDITIONAL ENERGY SLIDES OVERHEAD IN DEVELOPING
TROUGH AXIS. CYCLONIC FLOW AND FORCED UPSLOPE INTO THE HIGHLANDS
SHOULD ONLY HELP THE CAUSE. SAME STORY GOES FOR SUNDAY...WITH AN
ADDITIONAL SHORTWAVE TROUGH/SURFACE REFLECTION AND ASSOCIATED
CONVERGENCE/WEAK LAKE RESPONSE KEEPING THE SHOWER THREAT GOING.
AFTER HIGHS IN THE 60S AND LOWER 70S SATURDAY...IT WILL BE
NOTICEABLY CHILLIER SUNDAY...A GOOD 10 OR SO DEGREES COOLER.

TROUGHING BEGINS TO RELAX HEADING INTO THE BEGINNING OF NEXT
WEEK...ALTHOUGH WILL NEED TO WATCH FOR PERHAPS ONE LAST WAVE DIVING
ALONG ITS BACKSIDE LATER MONDAY/MONDAY NIGHT. MORE SIGNIFICANT
CHANGES BEGIN TO TAKE PLACE HEADING INTO MID WEEK WITH GROWING
SUPPORT FOR RAPID HEIGHT RISES BEGINNING AS EARLY AS TUESDAY...WITH
OVERHEAD RIDGING BY WEDNESDAY. SURFACE HIGH PRESSURE ALSO SPREADS
ACROSS THE REGION...AND THE ABOVE COMBO SHOULD LEAD TO
QUIET CONDITIONS RIGHT THROUGH THURSDAY (AND LIKELY BEYOND IF THINGS
SET UP AS GUIDANCE SUGGESTS). SLOW WARMING TREND EXPECTED RIGHT
THROUGH THE WEEK...WITH HIGHS BY THURSDAY BACK TO THE MID AND UPPER
60S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 651 AM EDT FRI SEP 19 2014

PERIOD OF MVFR CEILINGS AT PLN THIS MORNING...OTHERWISE VFR
CONDITIONS EXPECTED THROUGH THE DAY WITH GUSTY WINDS THIS
AFTERNOON. CLOUDS WILL LOWER WITH RAIN SHOWERS MOVING INTO
NORTHWEST LOWER TONIGHT. LOW LEVEL WIND SHEAR LIKELY TO BECOME AN
ISSUE AS WELL.

&&

.MARINE...
ISSUED AT 420 AM EDT FRI SEP 19 2014

GRADIENT EXPECTED TO TIGHTEN UP DURING THE DAY TODAY...AND WHILE
STRONG WARM ADVECTION WILL LIMIT MIXING OVER THE WATER...GRADIENT
PLUS SOME ISALLOBARIC CONTRIBUTION WILL SUPPORT WINDS APPROACHING
GALE FORCE WITHIN NORTHERN LAKE MICHIGAN ZONES...ESPECIALLY SOUTH OF
GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE AND WINDS FUNNELING
THROUGH THE MANITOU PASSAGE WON`T HURT.  SO WILL HOIST A GALE
WARNING FOR THE MANISTEE TO GRAND TRAVERSE LIGHT NEARSHORE
ZONES...WITH SMALL CRAFT ADVISORIES FOR THE REMAINING LAKE MICHIGAN
NEARSHORE ZONES...AND WILL SPIN UP AN ADVISORY FOR WHITEFISH BAY
STARTING THIS AFTERNOON.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 5 AM EDT SUNDAY FOR
     LMZ323-341-342.
     GALE WARNING FROM 5 PM THIS AFTERNOON TO 8 AM EDT SATURDAY FOR
     LMZ344>346.
LS...SMALL CRAFT ADVISORY FROM NOON TODAY TO 8 AM EDT SATURDAY FOR
     LSZ321.

&&

$$

SYNOPSIS...MSB
SHORT TERM...JPB
LONG TERM...MSB
MARINE...JPB






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