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000
FXUS63 KAPX 172005
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
405 PM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 405 PM EDT FRI MAY 17 2013

AS HIGH PRESSURE EXITS TOWARD THE NORTH ATLANTIC...NORTHERN
MICHIGAN`S WEATHER WILL GROW INCREASINGLY UNSETTLED INTO THE
WEEKEND...WITH SCATTERED SHOWERS POSSIBLE MAINLY ON SATURDAY. A
STORM SYSTEM CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO
THE PLAINS ON SATURDAY AND INTO THE GREAT LAKES TO START THE WORK
WEEK. THIS WILL GENERATE SHOWERS AND THUNDERSTORMS WHILE CONTINUING
EXTREMELY WARM TEMPERATURES OVER NORTHERN MICHIGAN INTO MIDWEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RATHER INTERESTING FORECAST UNFOLDING THIS AFTERNOON...WITH REMNANTS
OF UPSTREAM EARLY MORNING MCS SPREADING ALONG THE M-55 CORRIDOR...
IN-SPITE OF PERSISTENT LOW LEVEL DRYING. WIDESPREAD LIGHT RAINS THE
RESULT SOUTH OF GRAND TRAVERSE BAY...WITH DEEP LAYER DRY WEDGE AND
LACK OF FORCING MAINTAINING DRY WEATHER ELSEWHERE. TEMPERATURES HAVE
RESPONDED ACCORDINGLY...WITH THE "WARMEST" READINGS WELL INTO THE
60S ACROSS THE NORTH...WITH THOSE EXPERIENCING RAIN STUCK MAINLY IN
THE 50S. FORECAST CONCERNS THROUGH SATURDAY CENTER ON ADDITIONAL
RAIN CHANCES AS WELL AS CLOUD AND TEMPERATURE TRENDS.

OVERNIGHT CONFIDENCE HAS TAKEN A REMARKABLE DOWNWARD TREND AFTER
TODAY`S EVENTS. BEST GUESS SUGGESTS ONGOING ACTIVITY WILL WANE
THROUGH THE AFTERNOON...WITH INCREASING FOCUS FOR RENEWED ACTIVITY
FURTHER TO OUR NORTHWEST WHERE MOISTURE/MASS CONVERGENCE IS
MAXIMIZED ON NOSE OF LOW LEVEL JET AND ALONG ELEVATED WARM FRONT.
DESPITE SOME LOW LEVEL MOISTENING...FEEL BEST BET FOR ANY RAINS
REACHING THE SURFACE WILL REMAIN ACROSS WISCONSIN INTO WESTERN UPPER
MICHIGAN THROUGH THE OVERNIGHT. NORTHEAST BOWING THETA-E RIDGE MAY
SUPPORT SOME LIGHT SHOWERS ADVANCING EAST FROM GENERATION
REGION...PERHAPS BRINGING SOME SCATTERED LIGHT SHOWERS TO PARTS OF
THE AREA (ESPECIALLY THE WESTERN HALF WHERE LOW LEVEL MOISTURE WILL
BE DEEPER). WILL CONTINUE TO WORD AS SUCH...KEEPING JUST LOW END
MENTION FOR LIGHT SHOWERS SLOWLY ADVANCING NORTH WITH TIME. PLENTY
OF CLOUDS TONIGHT SUPPORTS MUCH WARMER TEMPERATURES THAN THOSE
OBSERVED LAST NIGHT...WITH WIDESPREAD READINGS IN THE 40S.

PERHAPS SOME LINGERING LIGHT SHOWERS SATURDAY MORNING...OTHERWISE A
MAINLY DRY DAY IS EXPECTED AS MID LEVEL RIDGING BUILDS OVERHEAD AND
FOCUS FOR ADDITIONAL SHOWERS SHUNTS EVEN FURTHER NORTHWEST. CLOUDS
SHOULD DOMINATE EARLY...WITH TRENDS SUPPORTING SOME AFTERNOON
CLEARING SPREADING IN FROM THE SOUTHWEST. TEMPERATURES HIGHLY
DEPENDENT ON JUST HOW AGGRESSIVE CLEARING BECOMES. A BLEND BETWEEN
COOL GUIDANCE AND INHERITED WARM READINGS SEEMS AS GOOD A STARTING
POINT AS ANY...GIVING HIGHS IN THE UPPER 60S AND LOWER 70S.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RECENT TRENDS: TEMPERATURES...STARTING TO RECOVER FROM RECENT COOL
SPELL...3-4C BELOW NORMAL LAST 7 DAYS AND NEAR TO A LITTLE (1-2C)
ABOVE NORMAL FOR THE MONTH OF MAY (WESTERN AND LOWER GREAT LAKES/NEW
ENGLAND WARMTH...COOL IN BETWEEN AND ACROSS THE SOUTHEAST AND GULF
COAST.  PRECIPITATION/HYDROLOGY...BEEN DRIER PAST COUPLE OF DAYS...
PRECIP LAST 7 DAYS 150-300 PERCENT NORMAL EAST OF I-75...MUCH DRIER
ACROSS EASTERN UPPER AND WEST OF US-131 CORRIDOR.  MONTH-TO-DATE
BELOW NORMAL PRECIP EXCEPT SMALL AREA OF NORTHEAST LOWER CENTERED
AROUND ALPENA (SUBSTANTIALLY DRIER DOWNSTATE).  30 DAY STANDARDIZED
PRECIP INDEX MOSTLY NEAR NORMAL.  SOIL MOISTURE ABOVE AVERAGE ACROSS
THE FORECAST AREA...MEAN STREAMFLOWS RUNNING NEAR TO ABOVE NORMAL ON
AREA RIVERS.

LARGE SCALE PATTERN/FORECAST: PROGRESSIVE 5 WAVE HEMISPHERIC PATTERN
WITH LONG WAVE TROUGHS OVER EASTERN CANADA/NEW ENGLAND AND THE
NORTHEAST PACIFIC.  PACIFIC HEIGHT FALLS MOVING ONTO THE WEST COAST
WITH A GRADUAL AMPLIFYING OF THE PATTERN IN RESPONSE...WITH RIDGING
BUILDING ACROSS THE NORTHERN PLAINS/CANADIAN PRAIRIES WITH A REMNANT
CLOSED LOW STUCK BENEATH THE RIDGE MOVING INTO THE TENNESSEE
VALLEY.  GOING FORWARD...SPLIT IN THE FLOW PATTERN EXPECTED TO
DEVELOP OUT WEST AS WESTERN TROUGH CROSSES THE ROCKY MOUNTAINS AND
INTO THE NATION`S MIDSECTION EARLY NEXT WEEK WHILE UPPER HIGH
DEVELOPS OVER THE CANADIAN PRAIRIES IN A BIT OF A SMALL SCALE
BLOCKING PATTERN.  QUASI-EAST/WEST ORIENTED FRONTAL BOUNDARY RUNNING
FROM THE NORTHERN PLAINS ACROSS THE MID MISSISSIPPI VALLEY/OHIO
VALLEY THIS AFTERNOON WILL BE A FOCUS FOR PRECIPITATION DEVELOPMENT
OVER THE COMING DAYS...WITH THE WESTERN PORTION OF THE FRONT GETTING
PUSHED NORTHWARD IN RESPONSE TO FALLING PRESSURES TO THE LEE OF THE
ROCKIES.  EVENTUALLY...THIS FRONT MERGES WITH A COLD FRONT WITHIN
THE NORTHERN BRANCH FOLDING IN FROM THE NORTH ON MONDAY AS UPPER
LEVEL ENERGY PUSHES INTO THE MIDWEST. SO TRYING TO DISCERN RAIN
CHANCES OVER THE COMING DAYS AS THESE FEATURES COME TOGETHER WILL BE
THE MAIN WEATHER CONCERN INTO EARLY NEXT WEEK.

SATURDAY NIGHT THROUGH MONDAY: SHORT WAVE RIDGING WILL BUILD INTO
THE UPPER LAKES SATURDAY NIGHT...WITH PERSISTENT LOW/MID LEVEL WARM
ADVECTION AS NORTHERN MICHIGAN SHOULD STILL BE ON THE COOL SIDE OF
THE OHIO VALLEY BAROCLINIC ZONE.  SHOULD STILL BE SOME CLOUDS AROUND
SATURDAY NIGHT WITHIN WARM ADVECTION/ISENTROPIC ASCENT...PROBABLY
CAN`T RULE OUT SOME SPOTTY LIGHT RAIN SHOWERS ESPECIALLY THE FARTHER
NORTH ONE GOES.  BUT THE GENERAL TREND OF IMPROVING CONDITIONS INTO
SUNDAY STILL LOOKS REASONABLE.  LOOKS LIKE BOUNDARY TO THE SOUTH
WILL TEND TO WEAKEN/MIX OUT SUNDAY...WITH AN INCREASE OF LOW LEVEL
MOISTURE INTO LOWER MICHIGAN WITH SOUTHERLY WINDS.  PROBABLY A
LITTLE TOO MOIST IN SOME OF THE GUIDANCE (E.G., NAM-WRF)...THUS WILL
KEEP THE FORECAST DRY AS IS CURRENTLY AND NOT INTRODUCE DIURNALLY
DRIVEN CONVECTIVE SHOWERS INTO THE FORECAST FOR SUNDAY AFTERNOON.
EXPECT SUNDAY AFTERNOON TO BE WARM WITH HIGHS WELL INTO THE 70S/
AROUND 80.

DEVELOPING/STRENGTHENING BAROCLINIC ZONE TO THE NORTH OF MICHIGAN
FORECAST TO BECOME BETTER ORGANIZED SUNDAY NIGHT INTO MONDAY AS IT
PRESSES SOUTH INTO THE UPPER PENINSULA AND POSSIBLY NUDGING INTO
NORTHERN LOWER MICHIGAN (AIDED BY COOL LAKE BREEZE CIRCULATION??).
POTENTIALLY ANOTHER WARM AND MORE HUMID AFTERNOON MONDAY...FORECAST
SOUNDINGS HAVE A LITTLE MORE CAPPY LOOK TO THEM BUT WILL HANG ONTO A
CHANCE OF THUNDERSTORMS FOCUSED MAINLY ON THE DIURNAL CYCLE.

EXTENDED FORECAST (TUESDAY THROUGH FRIDAY): UNSETTLED WEATHER
THROUGH MIDWEEK AS BOUNDARY CONTINUES TO SAG INTO THE LOWER
PENINSULA...WITH CHANCES FOR THUNDERSTORMS BOTH TUESDAY AND
WEDNESDAY.  IF THE FRONT CAN CLEAR THE AREA WEDNESDAY NIGHT SHOULD
BE ABLE TO DRY THINGS OUT HEADING INTO THURSDAY/FRIDAY...BUT NOT
CERTAIN ABOUT HOW QUICKLY UPPER WAVE WILL MOVE OUT AND SUSPECT THAT
IT WILL BE SLOWER THAN DEPICTED BY THE GFS.  SO WILL SPLIT THE
DIFFERENCE HERE...DRAGGING POPS INTO THURSDAY THEN GOING DRY FOR
FRIDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 116 PM EDT FRI MAY 17 2013

VFR CONDITIONS EXPECTED. EXTENSIVE DECK OF HIGH AND MID LEVEL
CLOUDS WILL CONTINUE TO AFFECT ALL TAF SITES RIGHT INTO SATURDAY
MORNING. LIGHT RAINS ALREADY OCCURRING AT KMBL...AND SHOULD
CONTINUE TO DO SO FOR THE NEXT FEW HOURS. RAINS MAY EDGE NORTH TO
TVC LATER THIS AFTERNOON...ALTHOUGH WITH NO IMPACT TO VIS. LIGHT
WINDS WILL REMAIN ACROSS THE AREA.

&&

.MARINE...
ISSUED AT 405 PM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TONIGHT WITH NO
MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES SATURDAY
THROUGH SUNDAY AND A HANDFUL OF SMALL CRAFT ADVISORIES MAY BE
NEEDED AT THAT TIME.

&&

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

&&

$$

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