Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 060546
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
146 AM EDT SUN JUL 6 2014

.SYNOPSIS...
ISSUED AT 409 PM EDT SAT JUL 5 2014

HEAT AND HUMIDITY WILL INCREASE THROUGH SUNDAY AHEAD OF A COLD FRONT
ASSOCIATED WITH A LOW PRESSURE SYSTEM APPROACHING THE NORTHERN GREAT
LAKES REGION. ALONG WITH THE INCREASED HEAT AND HUMIDITY COMES
CHANCES FOR SHOWERS AND THUNDERSTORMS...PARTICULARLY INTO SUNDAY
EVENING. SOMEWHAT COOLER AND LESS HUMID CONDITIONS WILL MAKE A
RETURN INTO MUCH OF NEXT WEEK...COMPLETE WITH A FEW MORE CHANCES FOR
SHOWERS THROUGH WEDNESDAY.

&&

.UPDATE...
ISSUED AT 951 PM EDT SAT JUL 5 2014

DIURNAL CU OVER NORTHERN LOWER MI CONTINUES TO FIZZLE. HOWEVER...
CIRRUS HAS STARTED TO ADVANCE INTO THE REGION...AHEAD OF AN AREA
OF SHRA/TSRA OVER WESTERN SUPERIOR AND WESTERN UPPER MI. HAVE BEEN
FIDDLING WITH CLOUD COVER TRENDS THIS EVENING...AS WE CLEARED VERY
QUICKLY BUT HAVE RETURNED TO PARTIAL CLOUD COVER ALMOST AS QUICKLY.

THAT AREA OF CONVECTION UPSTREAM HAS ONLY BEEN MAKING VERY SLOW
EASTWARD PROGRESS. THERE IS A CONSIDERABLE W-E 850MB THETA-E
GRADIENT IN PLACE ACROSS THE LAKES REGION...WITH GRB 5C WARMER
THAN APX IN THE 00Z SOUNDINGS. WITH STEADY SW LOW-LEVEL FLOW...THE
JUICIER SUB-700MB AIR WILL GRADUALLY INTRUDE INTO NW LOWER AND
EASTERN UPPER MI OVERNIGHT. THIS WILL PROVIDE A SLIGHTLY MORE
FAVORABLE ENVIRONMENT FOR UPSTREAM CONVECTION TO SURVIVE...AND/OR
IGNITE NEW ACTIVITY (PERHAPS OVER THE COLD DOMES OF LAKES
MI/SUPERIOR). HAVE SLIGHTLY ACCELERATED THE ONSET OF CHANCE POPS
OVERNIGHT...GIVEN UPSTREAM RADAR TRENDS.

NO MAJOR CHANGES TO TEMPS.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 409 PM EDT SAT JUL 5 2014

SW FLOW AND DEEPER MOISTURE AXIS IN PLACE FROM THE PLAINS INTO THE
FAR WESTERN AND NORTHERN GREAT LAKES THIS AFTERNOON. ELEVATED
CONVECTION HAS BEEN PERSISTENT ACROSS LAKE SUPERIOR WITH SOME LIGHT
SHOWERS UNFORTUNATELY GETTING INTO EASTERN UPPER MICHIGAN OVER THE
LAST FEW HOURS. MORE ROBUST CONVECTION HAS DEVELOPED NEAR THE
ARROWHEAD OF MINNESOTA ALONG EASTERN FRINGE OF TRUE INSTABILITY
AXIS/STEEPER LAPSE RATES ALOFT...AIDED BY ANOTHER SUBTLE SHORT WAVE
DROPPING DOWN THROUGH THAT AREA.

ACROSS THE CWA...BONE DRY AIRMASS IN PLACE THIS MORNING. BUT
MOISTURE ADVECTION ON SW FLOW HAS BEEN INCHING LOW LEVEL DEWPOINTS
UPWARD A BIT TODAY...EVIDENCED BY DECENT CU DEVELOPMENT OVER NW
LOWER MICHIGAN AND OF COURSE SFC DEWPOINTS PUSHING INTO THE 50S.

FORECAST CHALLENGE CONTINUES TO REVOLVE AROUND CHANCES FOR
CONVECTION...WITH MANY POSSIBLE OUTCOMES. FIRST OFF...SMALL MCS
COMPLEX PASSING THROUGH THE MINNESOTA ARROWHEAD INTO LAKE SUPERIOR
WILL LIKELY OUTRUN BETTER INSTABILITY FURTHER TO THE WEST HEADING
INTO THE EVENING AND SPUTTER OUT...ALTHOUGH REMNANT SHOWERS COULD
CERTAINLY SURVIVE AND EVENTUALLY GET INTO EASTERN UPPER MICHIGAN.
MEANWHILE...UPSTREAM THETA-E AXIS WILL GRADUALLY FOLD INTO THE GREAT
LAKES THROUGH THE COURSE OF THE NIGHT AS UPSTREAM LOW PRESSURE AND
DEVELOPING COLD FRONT PRESSES INTO THE REGION. BUT WE NEVER REALLY
GET INTO THE BETTER UPSTREAM INSTABILITY/REALLY STEEP LAPSE RATES
WHICH BASICALLY WEAKENS AS WE GO THROUGH THE NIGHT...AND SUGGESTS
THAT ANY UPSTREAM CONVECTION WILL HAVE A DIFFICULT TIME GETTING INTO
THE CWA TONIGHT.

SO...AM REASONABLY SURE THE EVENING STAYS DRY AND HAVE TRIMMED BACK
POPS ACCORDINGLY. HAVE BEEN MULLING OVER TRIMMING BACK POPS
OVERNIGHT AS WELL. BUT THERE ARE JUST TO MANY UNKNOWNS WHEN IT COMES
TO CONVECTION. SOMETHING COULD GET GOING TO OUR WEST AND MAKE A RUN
AT THE CWA. COULD ALSO SEE DEVELOPMENT OFF LAKE MICHIGAN OVERNIGHT
AS BETTER MOISTURE ARRIVES AND LOW LEVEL JET GETS LOCALLY RAMPED UP
OVER THE STABLE MARINE LAYER. AGAIN...LOTS OF POSSIBILITIES.
THUS...WILL MAINTAIN LOW CHANCES FOR SHOWERS/STORMS ACROSS THE
NRN/WRN PART OF THE CWA AT THIS JUNCTURE.

.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 409 PM EDT SAT JUL 5 2014

...THUNDERSTORMS POSSIBLE SUNDAY/SUNDAY NIGHT...

HIGH IMPACT WEATHER POTENTIAL: CHANCE OF THUNDERSTORMS SUNDAY/SUNDAY
NIGHT (PROBABLY NOT SEVERE).

PATTERN SYNOPSIS/FORECAST: WHILE MEAN LONG WAVE PATTERN CONTINUES TO
EXHIBIT A GENERAL FOUR WAVE LOOK TO IT WITH MEAN TROUGHING OVER
EASTERN NORTH AMERICA AND RIDGING WEST...FLOW ACROSS THE NORTHERN
TIER OF STATES HAS MOSTLY FLATTENED OUT TO START THIS WEEKEND...WITH
SHORT WAVE TROUGHING MOVING THROUGH NEW ENGLAND AND SCOOPING THE
REMNANTS OF TROPICAL CYCLONE "ARTHUR" INTO ATLANTIC CANADA.  BROAD
TROUGHING REMAINS OVER THE NORTHEAST PACIFIC...AND ZONAL JET PATTERN
ACROSS THE NORTHERN CONTINENTAL U.S. CONTAINS A NUMBER OF SMALL
SHORT WAVE TROUGHS EMBEDDED WITHIN IT.  AT THE SURFACE...1027MB HIGH
PRESSURE CENTERED OVER OHIO WITH ANTICYCLONIC SOUTHWESTERLY BOUNDARY
LAYER FLOW SETTING UP ACROSS THE UPPER GREAT LAKES REGION.  NARROW
AXIS OF HIGHER PRECIPITABLE WATER EXTENDS FROM THE TEXAS GULF COAST
NORTHWARD ALONG THE EAST SIDE OF THE GREAT PLAINS AND INTO THE UPPER
MIDWEST HELPING FUEL AREAS OF CONVECTION WITHIN WARM ADVECTION
PATTERN AND AIDED BY EMBEDDED SHORT WAVE TROUGHS.

MEAN TROUGHING BECOMES MORE AMPLIFIED OVER THE UPPER GREAT LAKES TO
START NEXT WEEK WITH A PAIR OF SHORT WAVE TROUGHS DROPPING INTO THE
REGION FROM WESTERN CANADA.  LEAD PUSH OF HEIGHT FALLS ARRIVES LATER
SUNDAY INTO MONDAY...WHICH WILL SEND A COUPLE OF COLD FRONTS ACROSS
MICHIGAN...ONE SUNDAY NIGHT/EARLY MONDAY AND A SECONDARY FRONT
MONDAY AFTERNOON/NIGHT.  MOISTURE WILL INCREASE ACROSS NORTHERN
MICHIGAN LATER TONIGHT AND SUNDAY AHEAD OF THE LEAD FRONTAL BOUNDARY.

PRIMARY FORECAST CONCERNS (NEAR TERM): PRECIPITATION CHANCES AHEAD
OF INITIAL COLD FRONT SUNDAY/SUNDAY NIGHT...AND WILL WE BE ABLE TO
DRY THINGS OUT IN THE WAKE OF THIS FRONT MONDAY?

NEAR TERM (SUNDAY/MONDAY): TRICKY FORECAST FOR SUNDAY WITH GOOD WARM
AIR/MOISTURE ADVECTION INTO NORTHERN MICHIGAN IN SOUTHWESTERLY FLOW
AHEAD OF THE LEAD COLD FRONT WHICH WILL MAKE ITS WAY INTO THE UPPER
MIDWEST DURING THE DAY.  BEST INSTABILITY WILL STILL BE UPSTREAM
CLOSER TO THE COLD FRONT...BUT WILL SEE AN INCREASE IN AT LEAST
ELEVATED INSTABILITY AND THE POSSIBILITY OF SOME CONVECTION POPPING
ALONG THETA-E RIDGE AXIS ACROSS THE NORTHERN HALF OF THE FORECAST
AREA.  WILL BE NOTICEABLY MORE HUMID ON SUNDAY THAN THIS AFTERNOON
AS DEW POINTS CLIMB THROUGH THE 50S AND INTO THE LOWER-MID 60S.
EXPECTING THUNDERSTORMS TO FIRE ACROSS THE MID/UPPER MISSISSIPPI
VALLEY SUNDAY AFTERNOON AIDED BY HEIGHT FALLS SPREADING IN FROM THE
NORTHWEST DURING THE AFTERNOON.  THIS ACTIVITY WILL THEN TRACK
TOWARD MICHIGAN...THOUGH HOW MUCH OF AN IMPACT IT WILL HAVE ON
NORTHERN MICHIGAN WILL DEPEND ON WHERE CONVECTION INITIATES AS
THUNDERSTORMS WILL LIKELY PROPAGATE TOWARD THE SOUTHEAST.  NOT GOING
TO RULE OUT ADDITIONAL DEVELOPMENT AS THE COLD FRONT SWINGS THROUGH
SUNDAY NIGHT...JUST THAT THE HEAVIEST ACTIVITY COULD END UP SLIDING
INTO SOUTHERN LOWER MICHIGAN.  BUT PLENTY OF TIME TO EVALUATE THAT.

COLD FRONT EXPECTED TO MOVE THROUGH NORTHERN LOWER MICHIGAN DURING
THE MONDAY MORNING TIME FRAME...WITH THE SECONDARY COLD FRONT
DROPPING IN QUICKLY ON ITS HEELS FROM THE NORTH ALONG WITH ANOTHER
SHORT WAVE TROUGH/PV ANOMALY.  MAY BE SOME ACTIVITY ALONG THE LEAD
FRONT ACROSS NORTHEAST LOWER MONDAY MORNING...QUESTION IS WILL
ENOUGH MOISTURE LINGER BEHIND THE LEAD FRONT TO ALLOW FOR SOME
INSTABILITY TO DEVELOP AHEAD OF THE SECONDARY FRONT MONDAY
AFTERNOON.  CAN`T RULE OUT THE POSSIBILITY ACROSS NORTHERN
LOWER...SO WILL CONFINE POPS TO BELOW THE BRIDGE FOR THE AFTERNOON
HOURS...THEN DRY THINGS OUT MONDAY NIGHT.

MEDIUM RANGE (TUESDAY/WEDNESDAY/THURSDAY): ANOTHER POSSIBILITY FOR A
SHORT WAVE TROUGH/ASSOCIATED COLD FRONT PASSAGE TUESDAY...AND WILL
HAVE TO WATCH ANOTHER FOR THE MIDWEEK PERIOD BRINGING A CHANCE FOR
RAIN SHOWERS WEDNESDAY.  DRY THURSDAY WITH TEMPERATURES STARTING TO
WARM.

OUTLOOK (FRIDAY/SATURDAY): DRY AND SEASONABLY WARM FRIDAY...
POTENTIAL COLD FRONT SATURDAY WITH ATTENDANT PRECIPITATION THREAT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 138 AM EDT SUN JUL 6 2014

PREDOMINATELY VFR WEATHER WILL CONTINUE TODAY ACROSS NRN
MICHIGAN. SW BREEZES WILL BRING INCREASING MOISTURE TO THE
REGION...AND THOUGH MVFR CONDITIONS ARE CURRENTLY BEING OBSERVED
UPSTREAM OVER WI...CEILINGS TODAY ARE EXPECTED TO REMAIN JUST
ABOVE THE MVFR THRESHOLD /AVERAGING 3.5-4.0 KFT/.

LLWS WILL BE POSSIBLE UNTIL DAYBREAK THANKS TO DECOUPLING AND AN
INCREASING PRESSURE GRADIENT.

ISOLATED CONVECTION MAY POP ACROSS FAR NRN AND ERN AREAS AFTER
18-19Z. AS A COLD FRONT APPROACHES FROM THE WEST...THE BEST
CHANCES FOR SHOWERS/THUNDERSTORMS WILL ARRIVE AFTER 00Z /WITH MVFR
VSBYS EXPECTED/.

&&

.MARINE...
ISSUED AT 409 PM EDT SAT JUL 5 2014

SOUTHWEST SYNOPTIC WINDS EXPECTED TONIGHT AND SUNDAY AND WILL BE ON
THE GUSTY SIDE OVER NORTHERN LAKE MICHIGAN NECESSITATING A SMALL
CRAFT ADVISORY (AND PERHAPS MAY NEED ONE WITHIN LAKE HURON NEARSHORE
ZONES SOUTH OF THUNDER BAY).  COLD FRONT WILL CROSS NORTHERN
MICHIGAN SUNDAY NIGHT/EARLY MONDAY WHICH VEERS WINDS AROUND TO THE
WEST AND NORTHWEST.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ323-341-342-
     344>346.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...TJL
SHORT TERM...ADAM
LONG TERM...JPB
AVIATION...SMITH
MARINE...JPB






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