Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 170247
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1047 PM EDT TUE SEP 16 2014

.SYNOPSIS...
ISSUED AT 311 PM EDT TUE SEP 16 2014

A WEAK SURFACE BOUNDARY OVER LAKE SUPERIOR...WILL GENERATE A FEW
RAIN SHOWERS NORTH OF THE STRAITS OF MACKINAC TONIGHT AND WEDNESDAY.

OTHERWISE A LARGE AREA OF HIGH PRESSURE CENTERED IN THE OHIO
VALLEY AND GREAT LAKES...WILL GENERATE SOME SUN AND NEARLY SEASONAL
TEMPERATURES ACROSS NORTHERN MICHIGAN TO END THE WORK WEEK.

HOWEVER...A STORM SYSTEM ORGANIZING OVER THE PACIFIC NORTHWEST...
WILL PUSH INTO THE GREAT LAKES FRIDAY NIGHT. THIS PATTERN WILL
GENERATE WARM TEMPERATURES AND RAIN SHOWERS ACROSS NORTHERN MICHIGAN
THIS WEEKEND.

&&

.UPDATE...
ISSUED AT 1043 PM EDT TUE SEP 16 2014

EVERYTHING SEEMS TO BE GOING ALONG AS FORECAST. THE MID CLOUDS
THAT ARE INTO THE TIP OF THE MIT, ARE FALLING APART AS ARE THE
CLOUDS OVER UPPER MICHIGAN. MAIN AREA OF MOISTURE AND ENERGY IS
BEGINNING TO DESCEND FROM NEAR LAKE WINNEPEG/MINNESOTA ARROWHEAD
AND WILL GET INTO E UPPER AROUND 09Z OR SO AS WAS THOUGHT. SO WILL
KEEP THE FORECAST AS IS.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 311 PM EDT TUE SEP 16 2014

...MAINLY QUIET OVERNIGHT WITH A FEW SHOWERS POSSIBLE NORTH...

JUST A SPECTACULAR SEPTEMBER AFTERNOON ACROSS NORTHERN MICHIGAN! WE
CAN THANK SPRAWLING HIGH PRESSURE BRANCHING INTO OUR AREA FROM THE
MID MISSISSIPPI VALLEY...ALL WHILE A BACKDOOR COLD FRONT AWAITS JUST
UPSTREAM...CURRENTLY SLIDING THROUGH FAR SOUTHERN ONTARIO AS OF
EARLY AFTERNOON. THERE CONTINUE TO BE A HANDFUL OF SHOWERS ALONG
THAT FEATURE...HELPED ALONG BY A QUICK SHOT OF UPPER FORCING ON THE
SOUTHERN TAIL OF A SHORTWAVE DEPARTING TOWARD JAMES BAY. MEANWHILE...
A SECONDARY UPPER WAVE IS ANALYZED OVER CENTRAL MANITOBA...WITH THIS
FEATURE EXPECTED TO DROP INTO THE SOUTHERN PERIPHERY OF A MUCH
BROADER UPPER TROUGH ACROSS HUDSON BAY. THAT SETUP SHOULD MAKE AN
ATTEMPT AT PUSHING THE SURFACE COLD FRONT DOWN INTO THE EASTERN U.P.
OVERNIGHT...STALLING AS A WEAK SURFACE RIPPLE DEVELOPS ALONG THE
BOUNDARY.

FROM A PRECIPITATION STANDPOINT...BY FAR THE BEST RAIN CHANCES WILL
RESIDE JUST NORTH OF THE SURFACE WAVE...TIED TO A BRIEF ENHANCEMENT
OF UPPER JET SUPPORT AS WELL AS A QUITE STRONG LOW LEVEL
FRONTOGENETIC RESPONSE AS QUITE THE COLD AIRMASS BUILDS SOUTH
THROUGH ONTARIO. THIS SETUP IS VERY SIMILAR TO THE NUMEROUS CLIPPER
SYSTEMS WE TYPICALLY SEE IN THE WINTER...AND BELIEVE THIS ONE WILL
HAVE THE SAME EVOLUTION...WITH A BAND OF SHOWERS PERHAPS JUST
CLIPPING CHIPPEWA COUNTY MAINLY AFTER 09Z. SOUTH OF THESE AREAS...A
DRY NIGHT IS ON TAP AS HIGH PRESSURE HOLDS ITS GROUND...WITH ONLY
SOME INCREASE IN THICKER MID/HIGH CLOUDS FROM NORTH TO SOUTH
OVERNIGHT. A TIGHTENING GRADIENT WITH TIME SHOULD ACT TO KEEP THE
WINDS UP FOR MANY AREAS OVERNIGHT...LIGHTEST SOUTH WHERE THOSE AREAS
WILL BE DISPLACED FROM THE INCOMING FRONT. AS SUCH...SHOULD SEE A
NICE GRADIENT IN TEMPS FROM THE LOW OR MID 40S NORTH BENEATH THE
THICKER CLOUDS/MORE WIND...TO PROBABLY SOME MID OR UPPER 30S SOUTH
WHERE SKIES MAY REMAIN CLEAR MUCH OF THE NIGHT.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 311 PM EDT TUE SEP 16 2014

...COOL START THEN MODERATION FOR THIS WEEKEND...

HIGH IMPACT WEATHER POTENTIAL:

 *FROST POTENTIAL WEDNESDAY AND THURSDAY NIGHTS
 *SLIGHT CHANCE OF SEVERE THUNDERSTORM ACTIVITY THIS WEEKEND

PATTERN SUMMARY/FORECAST: EARLY AFTERNOON WATER VAPOR IMAGERY ACROSS
NORTH AMERICA REVEALS THE SEMI-PERMANENT RIDGE-TROUGH PATTERN WE/VE
BEEN FAMILIAR WITH THROUGHOUT THE SUMMER WITH NORTHERN MICHIGAN
FINDING ITSELF UNDER NORTHWEST FLOW ALOFT.  THIS AMPLIFIED PATTERN
LOOKS TO REMAIN IN PLACE FOR ANOTHER 1-2 DAYS BEFORE A STRENGTHENING
TROUGH OVER THE GULF OF ALASKA INVIGORATES THE UPPER JET OVER THE
NORTHEAST PACIFIC...DRIVING IT EASTWARD INTO WESTERN NOAM.  THIS
WILL FLATTEN THE DOWNSTREAM PATTERN FOR A TIME WITH BUILDING HEIGHTS
IN THE GREAT LAKES REGION BY THE END OF THIS WEEK AND TO BEGIN THE
COMING WEEKEND.  BEYOND THIS...HOWEVER...THERE IS GOOD
DETERMINISTIC/ENSEMBLE MODEL AGREEMENT THAT THE GULF OF ALASKA
TROUGH WILL CONTINUE TO DIG...CAUSING RENEWED AMPLIFICATION OF THE
DOWNSTREAM PATTERN WITH A RAPIDLY STRENGTHENING RIDGE ALONG THE
CONTINENTAL DIVIDE...WITH DOWNSTREAM TROUGHING TAKING SHAPE OVER THE
EASTERN HALF OF NOAM.

PATTERN IMPLICATIONS:  CERTAINLY COOL TO START THE PERIOD...BUT WITH
THE AFOREMENTIONED FLATTENING OF THE FLOW...EXPECT MODERATING
TEMPERATURES TO END THE WEEK...WITH LLEVEL TRAJECTORIES SUGGESTING A
SIGNIFICANT INCREASE IN LLEVEL MOISTURE AND THEREFORE...
PRECIPITATION POTENTIAL.  PRIMARY PRECIPITATION DRIVER LOOKS TO BE
LOW PRESSURE DEVELOPING IN THE GREAT LAKES REGION ON SATURDAY-
SUNDAY AS THE UPSTREAM RIDGE AMPLIFICATION DRIVES SHORTWAVE ENERGY
INTO THE SHARPENING TROUGH OVERHEAD.

MODEL AGREEMENT/CONFIDENCE: LARGE SCALE PATTERN AGREEMENT IS GOOD
THROUGH NEXT MONDAY...WITH THE GFS BECOMING AN OUTLIER BEYOND THIS
AS IT DRASTICALLY EXPANDS THE WESTERN RIDGE BY THE MIDDLE OF NEXT
WEEK.  THIS SOLUTION HAS LITTLE SUPPORT FROM THE 00/12Z ECMWF...THE
00Z EC-ENS AND THE 00Z GEFS...AND WAS DISCARDED.

MIDDLE RANGE /WEDNESDAY THROUGH FRIDAY/:

WEDNESDAY: SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ZIPS ALONG
SHARP BAROCLINIC ZONE NORTH OF THE GREAT LAKES WITH A THIN RIBBON OF
DEEPER MOISTURE ASSOCIATED WITH IT.  QG FORCING IS MODEST AND
OVERSPREADS THE REGION DURING THE MORNING COLLOCATED WITH MODEST
ASCENT ON THE 295K SURFACE.  WITH PWATS REACHING OVER 0.75 INCH
AHEAD OF THE SURFACE COLD FRONT...FEEL SOME SHOWERS ARE PROBABLE
OVER EASTERN UPPER...POTENTIALLY REACHING INTO NORTHEAST LOWER
DURING THE AFTERNOON. CERTAINLY NOT A SIGNIFICANT RAIN-MAKER WITH NO
MORE THAN 0.1" NORTH OF THE BRIDGE...AND LIKELY ONLY 1-2 HUNDREDTHS
TO THE SOUTH.  TEMPERATURES WILL BE HELD BACK BY THE CLOUDS/SHOWERS
OVER MUCH OF CHIPPEWA COUNTY WHERE HIGHS WILL STRUGGLE TO REACH MUCH
ABOVE 50.  60S LOOK REASONABLE SOUTH OF THE BRIDGE WITH T8S AROUND
5C.

COLD FRONT MOVES THROUGH THE REGION WEDNESDAY NIGHT WITH CANADIAN
HIGH PRESSURE SETTING UP SHOP JUST NORTH OF THE FORECAST AREA BY
DAYBREAK THURSDAY. DRY AIR PUSH LOOKS TO HOLD OFF UNTIL LATE EVENING
OVER EASTERN UPPER...AND NOT UNTIL AFTER MIDNIGHT FOR MUCH OF
NORTHERN LOWER.  AIRMASS ALOFT IS CERTAINLY COOL ENOUGH TO SUPPORT A
FROST...BUT WITH AFOREMENTIONED FRONTAL PASSAGE TIMING WE/LL HAVE TO
DEAL WITH CLOUD ISSUES.  ALSO...ARRIVING HIGH IS RATHER
ROBUST...LEAVING A MODEST NORTHEASTERLY GRADIENT OVERHEAD AFTER
MIDNIGHT.  BEST CHANCE FOR FROST WILL BE OVER EASTERN UPPER WHERE
THE GRADIENT IS LIGHTEST AND THE DRY AIR ARRIVES FIRST.  WILL
MAINTAIN PATCHY FROST WORDING OVER MUCH OF INTERIOR NORTHERN
LOWER...BUT AT THIS TIME THINK GREATEST CHANCES WILL BE IN THE
TYPICALLY COOLER SPOTS NORTH OF M-72.

THURSDAY:  HIGH PRESSURE IN CONTROL FOR THE DAY THURSDAY...SETTLING
TOWARDS THE NEW ENGLAND STATES THURSDAY NIGHT.  LIMITED MIXING DUE
TO THE PROXIMITY OF THE STRONG HIGH...COMBINED WITH T9S 4-8C FROM
NORTH TO SOUTH SUGGEST THAT 60 WILL BE HARD TO COME BY FOR MANY
SPOTS...SAVE PORTIONS OF NORTHWEST LOWER FROM TVC TO MBL.  A CHILLY
DAY LOOKS TO BE IN STORE OVER EASTERN UPPER/NORTHEAST LOWER GIVEN
TRAJECTORIES ARRIVING DIRECTLY FROM THE CANADIAN HIGH KEEPING TEMPS
FROM REACHING ABOVE THE LOWER 50S.  THESE COOL HIGHS AND A VERY DRY
AIRMASS IN PLACE /SIMILAR TO A HUDSON BAY HIGH SETUP/ SUGGEST
ANOTHER NIGHT OF POTENTIAL FROST.  CLOUDS LOOK TO BE LESS OF A
THREAT THURSDAY NIGHT /BUT WILL HAVE TO WATCH FOR SOME SHALLOW LAKE
STRATUS/...WITH THE PRIMARY LIMITING FACTOR FOR THE FROST BEING
DEVELOPING RETURN FLOW AFTER MIDNIGHT...PARTICULARLY CLOSER TO LAKE
MICHIGAN.  WILL EXPAND FROST MENTION SOME AND CONTINUE TO MENTION IN
THE AFTERNOON HAZARDOUS WEATHER OUTLOOK.

FRIDAY:  WARM ADVECTION REGIME STRENGTHENS DURING THE DAY WITH
BUILDING HEIGHTS ALOFT AND T8S WARMING FROM +5C TO START THE DAY TO
NEAR +10C BY FRIDAY EVENING.  SHORTWAVE IN THE DEVELOPING WESTERLY
FLOW ALOFT WILL MAKE A RUN AT THE REGION TOWARDS EVENING...WITH TOP
DOWN SATURATION DEVELOPING.  HOWEVER...THE LLEVELS LOOK TO REMAIN
RATHER DRY THROUGH 00Z SATURDAY...WITH PERHAPS A SPRINKLE/SHOWER
MAKING A RUN AT WESTERN CHIP/MACK...AND MAYBE THE COAST OF NW LOWER
BY LATE AFTERNOON.  THE QUICK WARM UP ALOFT WILL NOT BE
FULLY-REALIZED AT THE SURFACE GIVEN THE DEVELOPING STABLE PROFILES.
T9S RISING TO 10-12C WOULD ALLOW FOR MID 60S FULLY MIXED...IN LINE
WITH CURRENT EXPECTATIONS AND MODEL CONSENSUS.

LONG RANGE /SATURDAY THROUGH TUESDAY/:

A MILD...BUT UNSETTLED WEEKEND LOOKS TO BE IN STORE AS THE EASTERN
TROUGH RELOADS...WITH LOW PRESSURE MOVING THROUGH THE GREAT LAKES
REGION.  THE OVERALL CONSENSUS IDEA IS FOR A COLD FRONT TO SETTLE
INTO GREAT LAKES REGION FRIDAY NIGHT/EARLY SATURDAY WITH LOW
PRESSURE DEVELOPING NEAR THIS BOUNDARY SATURDAY NIGHT AND MOVING
EAST OF THE REGION ON SUNDAY.  POPS ARE WARRANTED THROUGH THE PERIOD
WITH INHERITED LIKELIES FOR MANY AREAS LOOKING GOOD GIVEN MODEST MODEL
AGREEMENT ON THIS EVOLUTION.

AS FOR THE DETAILS OF THE EVOLUTION...AGREEMENT IS SHAKIER...
ALTHOUGH IMPROVING WITH THE MOST RECENT GFS COMING ABOARD TO A MORE
ECMWF-LIKE SOLUTION /WITH GEFS SUPPORT AS WELL/...SUGGESTING A MORE
ROBUST UPSTREAM WAVE AND RESULTANT LOW PRESSURE DEVELOPMENT...
TRACKING NORTH OF THE FORECAST AREA. THIS PRESENTS AT LEAST SOME
POTENTIAL FOR SEVERE WEATHER SATURDAY NIGHT AHEAD OF THE ARRIVING
SURFACE COLD FRONT WITH H5 WINDS 50-60 KTS WITH CONCURRENT UPPER JET
SUPPORT AND A 40-50KT LOW LEVEL JET.  CLEARLY THESE DETAILS WILL
LIKELY CHANGE...BUT SOME POTENTIAL IS THERE FOR A HIGH SHEAR/LOW
CAPE SETUP.  CERTAINLY SOMETHING TO KEEP AN EYE ON IN THE COMING
DAYS.  SOME LOCALLY HEAVY RAIN POTENTIAL IS ALSO THERE GIVEN
THE AMOUNT OF MOISTURE AVAILABLE SOUTH OF THE PRIMARY BAROCLINIC
ZONE /PWATS ~1.5"/.

TEMPERATURES THIS WEEKEND WILL BE LARGELY MODULATED BY RAINFALL
PLACEMENT...BUT IT WILL CERTAINLY BE WARMER/MUGGIER ON SATURDAY WITH
T8S ABOVE 10C...SUGGESTING POTENTIAL FOR SOME SPOTS TO REACH ABOVE
THE 70 DEGREE MARK.  ROBUST COLD ADVECTION LOOKS TO DEVELOP BEHIND
DEPARTING LOW PRESSURE TO END THE WEEKEND WITH TEMPERATURES FALLING
BACK TO SEASONAL NORMS ON SUNDAY.

A RETURN TO COOLER THAN NORMAL TEMPERATURES LOOKS TO BE IN STORE TO
START NEXT WEEK.  GIVEN THE DEEPER GREAT LAKES LOW SCENARIO EXPECTED
FOR SATURDAY-SUNDAY...LAKE EFFECT RAIN SHOWERS WILL BE POSSIBLE FOR
MONDAY...WITH FURTHER DOWNWARD TEMPERATURE ADJUSTMENTS NECESSARY IF
12Z GFS/00Z ECMWF CONSENSUS VERIFIES.  A FROST/FREEZE WOULD ALSO BE
LIKELY MONDAY NIGHT GIVEN THIS SCENARIO.  MODERATION IS LIKELY TO
END THE PERIOD TUESDAY...BUT TEMPERATURES LOOK TO REMAIN BELOW
SEASONAL NORMS /MID 60S/ THROUGH THE END OF THE FORECAST PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 813 PM EDT TUE SEP 16 2014

THERE ARE SOME VFR CIGS IN UPPER MICHIGAN, THAT WILL PROBABLY DROP
INTO N LOWER THIS EVENING. NOT EXPECTING THEM TO FALL BELOW VFR
CONDITIONS TONIGHT AS THE DRY AIR IN THE LOWER LEVELS SHOULD KEEP
CONDITIONS FROM DETERIORATING. THE CLOUDS WILL PROBABLY JUST
AFFECT PLN AND APN THIS EVENING, AND MAY BE TVC OVERNIGHT. THE VFR
CIGS AND VSBYS ARE EXPECTED TO REMAIN THROUGH WEDNESDAY EVENING.


&&

.MARINE...
ISSUED AT 311 PM EDT TUE SEP 16 2014

...GENERALLY HEADLINE FREE THROUGH THE WEEK...

SUMMARY: HIGH PRESSURE JUST SOUTH OF THE GREAT LAKES REGION WILL
GIVE WAY TO A FAST-MOVING LOW PRESSURE SYSTEM ON WEDNESDAY.  BEHIND
THIS SYSTEM...A LARGE AREA OF HIGH PRESSURE WILL DROP INTO THE GREAT
LAKES REGION FOR THE END OF THE WEEK...WITH GENERALLY QUIET
CONDITIONS EXPECTED OVER THE MARINE WATERS.

HEADLINES: WINDS/WAVES LOOK TO GENERALLY REMAIN BELOW SMALL CRAFT
LEVELS FOR MUCH OF THE WEEK...WITH SOME POTENTIAL FOR MARGINAL SMALL
CRAFT CONDITIONS WITH AFOREMENTIONED LOW PRESSURE SYSTEM WITH 20KT
WESTERLY GUSTS WEDNESDAY GIVING WAY TO NORTH-NORTHEASTERLY WINDS
WEDNESDAY NIGHT.

THUNDERSTORMS: NO THREAT OF THUNDER THROUGH FRIDAY.


&&

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

&&

$$

UPDATE...JL
SYNOPSIS...SWR
SHORT TERM...LAWRENCE
LONG TERM...ARNOTT
AVIATION...JL
MARINE...ARNOTT






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