000
FXUS63 KAPX 142343
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
743 PM EDT FRI JUN 14 2013

.SYNOPSIS...
ISSUED AT 347 PM EDT FRI JUN 14 2013

DRY AND SEASONABLY COOL WEATHER WILL CONTINUE TO SETTLE INTO
NORTHERN MICHIGAN AS WE WRAP UP THE WORK WEEK...WITH CANADIAN HIGH
PRESSURE BUILDING THROUGH THE GREAT LAKES. A SERIES OF UPPER LEVEL
DISTURBANCES WILL BRING A CHANCE OF SHOWERS OR EVEN A THUNDERSTORM
LATER SATURDAY INTO EARLY SUNDAY...AND AGAIN EARLY NEXT WORK WEEK.

&&

.UPDATE...
ISSUED AT 743 PM EDT FRI JUN 14 2013

CIRRUS LOOKS IN LINE TO MAKE BETTER INROADS LATE TONIGHT/SATURDAY
MORNING THAN EARLIER FORECAST. OTHERWISE FEW CHANGES NEEDED ON
THIS VERY QUIET EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 347 PM EDT FRI JUN 14 2013

CURRENTLY, HIGH PRESSURE IS SLOWLY DRIFTING OVER THE UPPER GREAT
LAKES REGION AT THE SFC. AT 500 MB, THE RIDGE AXIS IS JUST MOVING
INTO THE GREAT LAKES. ALONG AND BEHIND THIS RIDGE, THE WARM
ADVECTION AHEAD OF THE NEXT SFC LOW IS PRODUCING THUNDERSTORMS.

TONIGHT...THE SKY WILL REMAIN CLEAR, ESPECIALLY BELOW 500 MB AS THE
RIDGE AXIS MOVES TOWARD THE AREA. WITH THE CORE OF THE SFC HIGH OVER
US AND THEN DRIFTING SE OVERNIGHT, THE WINDS WILL DECOUPLE. THIS
WILL ALLOW OUR TEMPERATURES TO FALL TO THE MID TO UPPER 30S OVER
PORTIONS OF THE FORECAST AREA. WITH TEMPERATURES FALLING INTO THE
LOWER 30S IN NE LOWER, AWAY FROM LAKE HURON. THIS WILL PRODUCE
PATCHY FROST OVER MORE SANDY AREAS THAT RUNS FROM AROUND PELLSTON TO
NEAR ATLANTA THROUGH THE EASTERN PART OF THE HURON FOREST AND UP THE
AU SABLE RIVER VALLEY, AT THE BASE OF THE RIDGE THAT RUNS THROUGH
OGEMAW COUNTY.

SATURDAY...BY THE MORNING, THE 500 MB RIDGE AXIS WILL BE MOVING INTO
OUR AREA, AND EVEN FLATTENING. THE SFC HIGH WILL BE SE OF US,
ALLOWING THE RETURN FLOW START. MODELS ARE NOT IN GOOD AGREEMENT FOR
THE MOISTURE FLOWING INTO THE REGION. LOOKING AT THE 850 MB MOISTURE
THE GFS HAS IT THROUGH NE LOWER, WHILE THE ECMWF HOLDS OFF THE
MOISTURE AT 850 MB UNTIL AFTER 00Z. THE NAM IS KIND OF MIDDLE OF THE
ROAD. ECMWF LOOKS MORE CONSISTENT, AND THE NAM LOOKS TO BE LEANING
TOWARD THE ECMWF. SO KEPT A CHANCE IN N LOWER EXCEPT ALONG THE LAKE
HURON SHORE COUNTIES, WHERE IT WAS LEFT DRY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 347 PM EDT FRI JUN 14 2013

LARGE SCALE PATTERN/FORECAST: FOUR WAVE HEMISPHERIC PATTERN WITH A
TROUGH/RIDGE/TROUGH PATTERN PROGRESSING FROM WEST TO EAST ACROSS
NORTH AMERICA.  GREAT LAKES CAUGHT IN THE NORTHWESTERLY FLOW ALOFT
BETWEEN THE RIDGE OVER THE CENTRAL U.S. AND MEAN TROUGHING OVER THE
NORTHEASTERN STATES/EASTERN CANADA.  UPPER TROUGH OVER WESTERN
CANADA/PACIFIC NORTHWEST CONSISTS OF TWO PIECES OF ENERGY...ONE OF
WHICH IS GETTING KICKED TO THE NORTHEAST AS ANOTHER UPPER LOW DIGS
SOUTHEAST PAST 140W.  THIS LEAD SHORT WAVE TROUGH WILL FLATTEN THE
CENTRAL U.S. RIDGE AND EVENTUALLY REINFORCE/RETROGRADE THE
NORTHEASTERN TROUGH BACK CLOSER TO THE GREAT LAKES EARLY NEXT WEEK.
THIS SUPPRESSES THE REAL SUMMER HEAT WELL TO THE WEST THROUGH THE
EXTENDED PERIOD.

HIGH PRESSURE CURRENTLY RIDGING INTO THE GREAT LAKES FROM THE NORTH
WILL GIVE WAY TO A SLOW MOVING COLD/OCCLUDED FRONT ASSOCIATED WITH
THE SHORT WAVE TROUGH EJECTING FROM THE PACIFIC NORTHWEST.  WHAT
REMAINS OF THIS BOUNDARY WILL ARRIVE SUNDAY MORNING...FOLLOWED BY A
STRONGER PIECE OF UPPER LEVEL ENERGY FOR MONDAY.  SO FORECAST
PROBLEMS WILL FOCUS ON PRECIPITATION POTENTIAL WITH BOTH OF THESE
FEATURES.

SATURDAY NIGHT THROUGH MONDAY:  SENSIBLE WEATHER...AXIS OF 1.00-1.50
INCH PRECIPITABLE WATER VALUES PUSH INTO MICHIGAN BY SATURDAY
EVENING...ALONG WITH INCREASING ELEVATED INSTABILITY.  OVERALL
FORCING NOT PARTICULARLY STRONG... SOME LOW LEVEL WARM ADVECTION AND
UPPER DIVERGENCE WITHIN RIGHT READ QUADRANT OF A 100+KT JET STREAK
OVER NORTHEAST ONTARIO/QUEBEC.  ENOUGH TO CONTINUE THE THREAT FOR
SOME SHOWERS/THUNDERSTORMS SATURDAY NIGHT...QUESTION FOR SUNDAY
REMAINS DEGREE OF DRYING AS BOUNDARY LAYER WINDS SHIFT MORE
WESTERLY.  NAM-WRF IS CONSIDERABLY DRIER THAN GFS (OPPOSITE OF THE
TYPICAL BIAS BETWEEN THESE MODELS)...WILL PLAY THE MIDDLE OF THE
ROAD ON THIS WHICH SUGGESTS BEST AREA FOR INSTABILITY WILL BE OVER
THE SOUTHEAST CORNER OF THE FORECAST AREA.  THIS IS ALSO AN AREA
MOST LIKELY TO BE IMPACTED BY A BREEZE OFF LAKE HURON.  OTHERWISE
SOME LINGERING LOW CLOUDS/FOG SUNDAY MORNING SHOULD MIX OUT
REASONABLY QUICKLY.

SUNDAY NIGHT WILL SEE APPROACH OF NEXT SHORT WAVE TROUGH DROPPING IN
FROM THE NORTHWEST...WHICH WILL RAMP UP THE PRECIP CHANCES ONCE
AGAIN FIRST ACROSS THE UPPER PENINSULA SUNDAY NIGHT...THEN SPREADING
SOUTHEAST FOR MONDAY.  PASSAGE OF UPPER WAVE WITH DIURNAL HEATING
MAXIMUM ACROSS NORTHERN LOWER WILL SET THE STAGE FOR THUNDERSTORM
DEVELOPMENT AS WELL MONDAY AFTERNOON.

WINDS: LIGHT WEST/SOUTHWEST SATURDAY NIGHT...BECOMING MORE WESTERLY
10-15 MPH WITH SOME GUSTINESS FOR SUNDAY...MAYBE SOME LAKE BREEZE
DEVELOPMENT ON LAKE HURON SOUTH OF THUNDER BAY.  WINDS DIMINISHING
AGAIN SUNDAY NIGHT...WEAKNESS IN PRESSURE PATTERN MONDAY MAY RESULT
IN VARYING WIND DIRECTIONS FROM NORTH (EASTERLY) TO SOUTH
(WEST/SOUTHWESTERLY) ACROSS THE FORECAST AREA WITH LAKE BREEZE
COMPLICATIONS.

TEMPERATURES: MILD SATURDAY NIGHT AS CLOUDS AND A MORE HUMID AIR
MASS ADVECT INTO NORTHERN MICHIGAN...ADVENT OF SUNSHINE LATER SUNDAY
MORNING EXPECTED TO RESULT IN DECENT MIXING AND TEMPERATURES WELL
INTO THE 70S/NEAR 80.  MILD AGAIN SUNDAY NIGHT...MONDAY AFTERNOON
HIGHS WILL BE MUCH DEPENDENT ON CLOUD COVER AND PRECIP EVOLUTION...
STILL THINK SEASONABLE HIGHS LOOK FINE FOR NORTHERN LOWER BUT WILL
BE COOLER ACROSS EASTERN UPPER WHERE CLOUDS MORE LIKELY TO PLAY A
ROLE.

EXTENDED FORECAST (TUESDAY THROUGH FRIDAY): HIGH PRESSURE BUILDS
INTO THE UPPER LAKES TO START THE EXTENDED PERIOD TUESDAY...DRY BUT
TEMPERATURES PROBABLY  A BIT COOLER THAN MONDAY.  SIMILAR STORY FOR
WEDNESDAY BUT WILL TACK ON A COUPLE DEGREES FOR DAYTIME HIGHS.  SOME
INDICATIONS OF ENERGY WITHIN NORTHWEST UPPER LEVEL FLOW ON THURSDAY
PASSING IN THE VICINITY...BUT WILL KEEP THE FORECAST DRY FOR THE
TIME BEING.  BY FRIDAY BIG DIFFERENCES IN GUIDANCE DEPICTION OF
UPPER LEVEL FLOW EVOLUTION WITH PREFERRED ECMWF KEEPING HEIGHTS
SUPPRESSED OVER EASTERN CANADA AND EXTENDING BACK INTO THE GREAT
LAKES REGION.  WITH THIS IN MIND WILL START FRIDAY OUT DRY...
TEMPERATURES MAY END UP COOLER THAN WHAT WE HAVE GOING BUT
COLLABORATION ISSUES WILL RESULT IN TEMPERATURES CLOSER TO
CLIMATOLOGY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 743 PM EDT FRI JUN 14 2013

VFR. CHANCES FOR SHRA/PERHAPS TSRA ARRIVE SATURDAY AFTERNOON.

HIGH PRESSURE AND VERY DRY AIR IS OVERHEAD THIS EVENING. THE HIGH
WILL MOVE OFF TO THE SE OVER THE NEXT 24 HOURS...ALLOWING MORE
MOIST AIR TO GRADUALLY RETURN TO THE REGION. CIRRUS AND EVENTUALLY
MID CLOUDS WILL INCREASE LATE TONIGHT IN SATURDAY. LOWER CLOUDS
(3-6K FT) AND SHRA CHANCES WILL ARRIVE IN NW AND N CENTRAL LOWER
MI SATURDAY AFTERNOON/EVENING. SLIGHT CHANCE FOR A TSRA...HAVE NOT
INCLUDED ANY TS MENTION IN THE TAFS AT THIS TIME.

CALM WINDS TONIGHT. LIGHT SW BREEZE DEVELOPING SATURDAY...WITH APN
LIKELY SEEING A LAKE BREEZE IN THE AFTERNOON.

&&

.MARINE...
ISSUED AT 347 PM EDT FRI JUN 14 2013

THE SFC HIGH THAT DRIFTS ACROSS MICHIGAN TONIGHT WILL DRIFT
SOUTHEAST OF THE REGION. THE GRADIENT WITH THIS NEXT SYSTEM REMAINS
RATHER SLACK, SO WINDS WILL REMAIN WELL BELOW SMALL CRAFT CRITERIA
THROUGH SUNDAY. THE ONLY WEATHER TO WATCH FOR OUT ON THE LAKES WILL
BE THE SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON AND NIGHT, AND
THE MARINE FOG SATURDAY NIGHT INTO THE SUNDAY.


&&

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

&&

$$

UPDATE...JZ
SYNOPSIS...TJL
SHORT TERM...JSL
LONG TERM...JPB
AVIATION...JZ
MARINE...JSL