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000
FXUS63 KAPX 252300
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
700 PM EDT FRI JUL 25 2014

.SYNOPSIS...
ISSUED AT 400 PM EDT FRI JUL 25 2014

CLOUDS WILL CONTINUE TO INCREASE THIS AFTERNOON AS A QUICK MOVING
SYSTEM APPROACHES THE AREA. SHOWERS AND A FEW THUNDERSTORMS WILL
BE POSSIBLE TONIGHT INTO THE START OF THE WEEKEND. A STRONGER SYSTEM
IS EXPECTED TO ARRIVE BY TOWARD THE END OF THE WEEKEND...BRINGING A
BETTER POTENTIAL FOR SHOWERS AND THUNDERSTORMS SUNDAY INTO SUNDAY
NIGHT. TEMPERATURES WILL DROP TO WELL BELOW NORMAL READINGS FOR
MONDAY...WITH ONLY A SLOW MODERATION EXPECTED THROUGH THE REMAINDER
OF NEXT WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 400 PM EDT FRI JUL 25 2014

...SCATTERED SHOWERS MAYBE A THUNDERSTORM...

CURRENTLY, A WING OF WARM ADVECTION SHOWERS HAS BEEN CONTINUING,
ALBEIT WEAKLY, IN C AND E WISCONSIN, AND IN THE ARROWHEAD REGION OF
MINNESOTA. THE SHOWERS HAVE BEEN TRYING TO MOVE ACROSS LAKE
MICHIGAN, BUT HAVE BEEN HAVING A HARD TIME PUSHING INTO THE DRY AIR.
THE RETURN FLOW FROM THE SFC HIGH TO THE SE OF THE REGION HAS BEEN
ABLE TO WARM AND MOISTEN THE LOWER LEVELS OF THE ATMOSPHERE, BUT
THERE IS STILL SOME DRY AIR IN THE MID LEVELS (AROUND 700 MB) THAT
HAS BEEN ABLE TO INHIBIT THE RAIN. THERE IS A CAPPING INVERSION
THAT IS LIMITING THE CONVECTION AS WELL.

TONIGHT...THE MOISTENING IN THE MID LEVELS SHOULD BEGIN AFTER 00Z,
AND BY THE LOOKS OF THE MODEL SOUNDINGS, AND THE UPSTREAM SOUNDINGS
THIS MORNING, THE CHANCES FOR THE SHOWERS WILL INCREASE OVERNIGHT.
THIS ALSO COINCIDES WITH THE SFC TROUGH MOVING THROUGH THE FORECAST
AREA SO THAT BY 12Z, THE RAIN SHOWERS, AND ISOLATED THUNDERSTORM
SHOULD BE EXITING NE LOWER. HOWEVER, WITH THE MOISTURE AND THE FACT
THAT WE HAVEN`T BROKEN INTO THE WARM SECTOR, IT LOOKS LIKE THERE IS
STILL SOME CHANCES FOR RAIN SHOWERS BETWEEN 10Z AND 12Z IN NW LOWER.
ALTHOUGH WOULDN`T BE SURPRISED IF NOTHING HAPPENS AFTER THE SFC
TROUGH MOVES EAST OF I-75. TEMPERATURES SHOULD SLOWLY FALL, BUT NOT
FALL TOO MUCH OUT OF THE 60S OVERNIGHT WITH THE SW FLOW.

.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 400 PM EDT FRI JUL 25 2014

...RAIN CHANCES INCREASE AS THE WEEKEND PROGRESSES...

HIGH IMPACT WEATHER POTENTIAL: CHANCE FOR THUNDERSTORMS BOTH
SATURDAY AND SUNDAY.

PATTERN SYNOPSIS/FORECAST: LONG WAVE TROUGHS OVER THE NORTHEAST
PACIFIC AND EASTERN CANADA AND THE NORTHEAST QUADRANT OF THE U.S.
NORTH AMERICAN PATTERN WITHIN THIS FIVE WAVE HEMISPHERIC PATTERN
FEATURES A BROAD RIDGE ENCOMPASSING MUCH OF THE SOUTHERN U.S...
CLOSED CIRCULATION OVER EASTERN CANADA WITH TROUGHING EXTENDING INTO
THE NORTHEAST QUADRANT OF THE COUNTRY...WITH QUASI-ZONAL FLOW FROM
THE UPPER MIDWEST TO THE PACIFIC NORTHWEST WITH A SMALLER UPPER LOW
OVER THE PRAIRIE PROVINCES.  SURFACE ANALYSIS SHOWS HIGH PRESSURE
CENTERED OVER THE OHIO VALLEY/GREAT LAKES...SURFACE LOW ASSOCIATED
WITH PRAIRIES SHORT WAVE MOVING INTO SASKATCHEWAN WITH A TRAILING
COLD FRONT INTO THE DAKOTAS AND BACK WEST INTO THE CENTRAL GREAT
BASIN.  WEAK SURFACE WAVE OVER SOUTH DAKOTA HAS A WARM FRONT
EXTENDING SOUTH INTO THE LOWER MISSISSIPPI VALLEY.  NARROW AXIS OF
DEEPER MOISTURE RESIDES AHEAD OF THESE BOUNDARY ACROSS THE PLAINS/
MISSISSIPPI VALLEY (PRECIPITABLE WATER GENERALLY 1.00-1.50
INCHES)...DRIER POCKET OF AIR ACROSS LOWER MICHIGAN AND POINTS SOUTH
AND EAST.

SHORT WAVE TROUGH OVER THE CENTRAL CANADA WILL BE A BIG PLAYER IN
GREAT LAKES WEATHER THIS FORECAST CYCLE...WITH THIS WAVE EXPECTED TO
DIG SOUTHEAST AND HELP REINFORCE THE MEAN TROUGH OVER THE EAST WHILE
PULLING LOWER HEIGHTS BACK INTO THE GREAT LAKES.  THIS WILL SEND
ANOTHER SURGE OF COOL AIR INTO MICHIGAN FOR NEXT WEEK...PROBABLY
STARTING LATER SUNDAY INTO MONDAY.  INITIAL COLD FRONT OVER THE
NORTHERN PLAINS EXPECTED TO PUSH INTO MICHIGAN SATURDAY BUT
WEAKENING AS IT DOES...WITH A SECOND COLD FRONT MOVING THROUGH WITH
THE SHORT WAVE PASSAGE SUNDAY EVENING.

PRIMARY FORECAST CONCERNS (NEAR TERM): INCREASING RAIN THREAT THIS
WEEKEND WITH ARRIVAL OF INITIAL COLD FRONT SATURDAY...AND SHORT WAVE
DYNAMICS SUNDAY.

NEAR TERM (SATURDAY/SUNDAY):  SATURDAY WILL PROBABLY START OUT WITH
A GOOD DEAL OF CLOUD COVER...AND THE POSSIBILITY OF SOME SCATTERED
PRECIPITATION ALONG LOW LEVEL THERMAL GRADIENT ESPECIALLY EAST OF
THE US-131 CORRIDOR.  QUESTION FOR THE AFTERNOON IS POTENTIAL
DESTABILIZATION AHEAD OF WEAK SURFACE BOUNDARY THAT IS EXPECTED TO
PUSH INTO LOWER MICHIGAN DURING THE AFTERNOON.  DEW POINTS ARE
EXPECTED TO CLIMB INTO THE 60S...AND THOUGH CLOUDS MAY HANG ON FOR A
WHILE DO THINK WE`LL SEE ENOUGH THINNING TO GENERATE ON THE ORDER OF
500-1000J/KG MLCAPE AT LEAST ACROSS INTERIOR NORTHERN LOWER FOR THE
BOUNDARY TO WORK ON (ALONG WITH ANY LAKE BREEZE CONVERGENCE THAT MAY
FORM).  COULD BE A LAKE SHADOW ALONG NORTHWEST LOWER SHORELINE
COUNTIES PROVIDED NOTHING FORMS UPSTREAM ACROSS EASTERN WISCONSIN
AND TRIES TO MAKE A RUN ACROSS LAKE MICHIGAN.  BUT WILL KEEP
PROBABILITIES ON THE CHANCY SIDE...A LITTLE TOUGH TO GET A GOOD
HANDLE ON SOLID FEATURES TO FOCUS ON.  SATURDAY NIGHT LOOKS TO BE
RELATIVELY QUIET OUTSIDE OF ANY LINGERING PRECIPITATION DURING THE
EVENING...SOME FOG POSSIBLE WITH LIGHT WINDS AND A MOIST LOW LEVEL
AIR MASS.

MORE SUBSTANTIAL SHORT WAVE TROUGH WILL SWING SOUTHEAST OUT OF
WISCONSIN SUNDAY AND INTO LOWER MICHIGAN SUNDAY NIGHT...AND WITH IT
A MORE DEFINED CHANCE FOR SHOWERS/THUNDERSTORMS HEADING THROUGH THE
DAY SUNDAY.  RAINFALL SHOULD BE A COMBINATION OF SYNOPTIC/
FRONTOGENETIC FORCING TO THE NORTH OF THE TRACK OF THE SHORT WAVE
TROUGH (SPREADING IN FROM THE NORTH)...AND THE POSSIBILITY FOR
CONVECTIVE DEVELOPMENT OUT AHEAD OF THE SHORT WAVE TROUGH ACROSS
LOWER MICHIGAN AIDED BY DIURNAL HEATING.  SO PLAN TO CARRY HIGHER
RAIN CHANCES SUNDAY/SUNDAY NIGHT...WITH RAIN ENDING FROM NORTH TO
SOUTH SUNDAY NIGHT.

MEDIUM RANGE (MONDAY/TUESDAY/WEDNESDAY): COOL/BRISK NORTH/NORTHEAST
WINDS EXPECTED MONDAY AS THE NEXT SHOT OF COOL JULY AIR OVERSPREADS
THE UPPER GREAT LAKES.  WOULD EXPECT A GOOD BIT OF (MOSTLY)
DIURNALLY DRIVEN CLOUD COVER MONDAY...LOOKS MOSTLY DRY PROVIDED
SHORT WAVE TROUGH CLEARS LOWER MICHIGAN IN A TIMELY FASHION.
850MB TEMPERATURES FALLING BACK INTO THE SINGLE DIGITS AND
LIKELIHOOD OF CLOUD COVER SUGGEST ANOTHER DAY WITH HIGHS MAINLY IN
THE 60S.  THERMAL TROUGHING WILL BE HANGING AROUND THROUGH THE FIRST
PART OF THE WEEK...SURFACE PATTERN BECOMES PRETTY NON-DESCRIPT
SITTING BENEATH NORTHERLY FLOW ALOFT BUT WITH POTENTIAL FOR SOME
INSTABILITY WITHIN COLD AIR ALOFT ANY SMALL THING MAY GENERATE SOME
THREAT FOR PRECIPITATION.  LITTLE MORE MOISTURE POSSIBLE FOR
TUESDAY/WEDNESDAY WHICH MAY KICK UP THE CHANCES FOR SHOWER
DEVELOPMENT.  NOT EXPECT HIGHS TO WARM MUCH ABOVE THE LOWER-MID 70S
THROUGH MIDWEEK.

OUTLOOK (THURSDAY/FRIDAY):  STILL COOL THURSDAY...SHORT WAVE PASSAGE
MAY HELP GENERATE ANOTHER ROUND OF SCATTERED SHOWERS.  WILL START
FRIDAY OUT DRY...THOUGH THAT IS PRETTY MUCH A TOSS-UP AT THIS
POINT.  HIGH TEMPERATURES STILL NOT EXPECTED TO BE NEAR EARLY AUGUST
NORMALS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 700 PM EDT FRI JUL 25 2014

VFR CIGS WILL LOWER TO MVFR TOWARD DAYBREAK SATURDAY MORNING AS
LOW LEVEL MOISTURE INCREASES ALONG THE NRN EDGE OF AN INVERTED
TROUGH POKING INTO MICHIGAN. CHANCES OF RAIN SHOWERS AND POSSIBLY
A THUNDERSTORM WILL REMAIN PRESENT BUT SMALL THRU THE FORECAST
PERIOD...AND WILL HANDLE WITH VCSH FOR NOW. MAINLY LIGHT/VARIABLE
WINDS TONIGHT WILL BECOME SW AND EVENTUALLY WEST AOB 10 KTS ON
SATURDAY.

&&

.MARINE...
ISSUED AT 400 PM EDT FRI JUL 25 2014

PRESSURE GRADIENT REMAINS WEAK INTO THIS WEEKEND WHICH MAY PROMOTE
SOME ATTEMPT AT LAKE BREEZE DEVELOPMENT.  WINDS NOT REALLY EXPECTED
TO PICK UP UNTIL LATER SUNDAY INTO SUNDAY NIGHT AS A SHORT WAVE
TROUGH MOVES THROUGH AND PRESSURE GRADIENT TIGHTENS UP FROM THE
NORTH IN ITS WAKE.  SMALL CRAFT ADVISORIES MAY END UP BEING NEEDED
TO START NEXT WEEK.

&&

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

&&

$$

SYNOPSIS...MG
SHORT TERM...JSL
LONG TERM...JPB
AVIATION...MR
MARINE...JPB