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000
FXUS63 KAPX 010352
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1152 PM EDT THU JUL 31 2014

.SYNOPSIS...
ISSUED AT 334 PM EDT THU JUL 31 2014

AN AREA OF LOW PRESSURE CONTINUES TO LINGER AROUND JAMES BAY
BRINGING PERIODIC CHANCES FOR SHOWERS THROUGH SATURDAY ...ESPECIALLY
DURING THE AFTERNOON HOURS AND MAINLY ACROSS NORTHEAST LOWER
MICHIGAN. DRY WEATHER RETURNS TO END THE WEEKEND...WITH THE THREAT
FOR A FEW MORE SHOWERS TO START NEXT WORK WEEK. TEMPERATURES WILL
RETURN TO MUCH MORE SEASONAL LEVELS BY FRIDAY AND ON INTO THE
EXTENDED.

&&

.UPDATE...
ISSUED AT 1010 PM EDT THU JUL 31 2014

WHAT APPEARS TO BE THE LAST OF THE EASTERN UPPER-SPAWNED SHRA IS
PASSING SOUTH OF DRUMMOND ISL. DEEP CONVECTION CONTINUES TO
PERCOLATE ALONG AN AXIS FROM JUST S OF DULUTH MN TO JUST N OF
MUSKEGON MI. THIS IS GETTING NO CLOSER TO NORTHERN MI...NOR SHOULD
IT GIVEN A TENDENCY TOWARD DEEPER NORTHERLY FLOW.

CLOUD COVER IS TENDING TO DIMINISH...NOW THAT A LARGISH AREA OF MI
CLOUD IS MOVING EAST FROM APN/ROGERS. HOWEVER...ANOTHER SWIRL OF
LOW/MID CLOUDS COVERS THE NORTH HALF OF SUPERIOR...AND SHOULD
SPILL INTO EASTERN UPPER MI OVERNIGHT.

SOME MINOR TWEAKS MADE TO CLOUD COVER...BUT NO MAJOR CHANGES ARE
NEEDED FOR THE OVERNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 334 PM EDT THU JUL 31 2014

...FAIRLY QUIET OVERNIGHT...

HIGH IMPACT WEATHER POTENTIAL: NOT MUCH. PERHAPS A LITTLE SHALLOW
GROUND FOG LATER TONIGHT.

PATTERN SUMMARY: SAME PATTERN...DIFFERENT DAY. BROAD/ANOMALOUS
CLOSED UPPER LOW CONTINUES TO SPIN IN THE VICINITY OF JAMES BAY...
WITH FAIRLY DEEP AND COOL CYCLONIC FLOW PREVAILING ACROSS THE GREAT
LAKES. A SURFACE TROUGH AXIS IS ANALYZED AS OF 19Z JUST DIPPING INTO
THE EASTERN U.P....WORKING IN TANDEM WITH DEVELOPING INLAND LAKE
BREEZE CONVERGENCE TO HELP LIGHT OFF A FEW SHOWERS JUST NORTH OF THE
STRAITS. MEANWHILE...COOLISH AIR MASS ALOFT IS CONTRIBUTING TO A
SMATTERING OF DIURNAL CU ACROSS NORTHERN LOWER...DESPITE DEW POINTS
MIXING DOWN INTO THE 40S FOR INLAND SPOTS.

FORECAST: STILL WATCHING TO SEE IF WE CAN MANAGE A COUPLE OF
ADDITIONAL SHOWERS FIRING ALONG LOCALIZED LAKE BREEZE CONVERGENCE OF
NORTHEAST LOWER. SAID CONVERGENCE IS RELEGATED TO AREAS VERY CLOSE
TO THE COAST...AND WARMING ALOFT THE PAST 18 HOURS CERTAINLY WON`T
HELP. STILL...SUSPECT WE WILL REALIZE AT LEAST A FEW AND ISOLATED
POPS WILL BE MENTIONED THROUGH EARLY EVENING. MEANWHILE...ACTIVITY
TOWARD THE STRAITS WILL LIKELY CONTINUE A SLOW SOUTHEAST MIGRATION...
PROBABLY WEAKENING WITH TIME AS IT OUTRUNS THE SLIGHTLY BETTER
INSTABILITY (SUCH AS IT IS) AND LOW LEVEL CONVERGENCE.

HAD SOME EARLIER CONCERNS ACTIVITY ACROSS WISCONSIN MAY MAKE A RUN
AT SOUTHWEST PORTIONS OF THE CWA LATER THIS EVENING...BUT A CURRENT
LOOK OUT THAT WAY REVEALS A VERY FLAT CU FIELD OVER NORTHERN
PORTIONS OF THAT STATE. THAT CAN BE TRACED TO MODEST MIXING OF
BOUNDARY LAYER MOISTURE OUT THAT WAY...AND IT WOULD APPEAR ANY SUCH
ACTIVITY WILL REMAIN SOUTH OF OUR AREA THIS EVENING. ALL THE
WHILE...WATER VAPOR IMAGERY SHOWS ANOTHER IN A STRING OF SHORTWAVES
RIPPLING SOUTHWARD THROUGH THE FLOW OVER WESTERN ONTARIO...SET TO
ARRIVE HERE LATE. LIMITED MOISTURE WITH THIS FEATURE SUGGESTS A DRY
FORECAST IS PROBABLY THE WAY TO GO...THOUGH THIS MAY ACT TO KICK
SOME THICKER MID CLOUDS BACK OVER THE EASTERN U.P. ANOTHER
COMFORTABLE NIGHT TEMPERATURE-WISE...WITH VERY MINOR TWEAKS MADE TO
GOING LOWS DOWN IN THE UPPER 40S TO MID 50S. JUST LIKE LAST
NIGHT...LIGHT WIND REGIME AND TIME OF YEAR MAY ALLOW FOR SOME PATCHY
SHALLOW GROUND FOG ONCE AGAIN.

.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 334 PM EDT THU JUL 31 2014

...SCATTERED PRECIPITATION CHANCES NORTHERN LOWER THROUGH SATURDAY...

HIGH IMPACT WEATHER POTENTIAL: MINIMAL.

PATTERN SYNOPSIS/FORECAST: AMPLIFIED PATTERN CONTINUES ACROSS NORTH
AMERICA WITH UPPER LOWS OVER JAMES BAY AND THE NORTHEAST ATLANTIC...
AND RIDGING ACROSS WESTERN NORTH AMERICA.  LONG WAVE TROUGH THAT
ENCOMPASSES NORTHEAST PACIFIC LOW ALSO HAS ANOTHER STRONG SHORT WAVE
TROUGH EMERGING FROM THE ARCTIC AND INTO THE HIGH LATITUDES OF
NORTHWEST CANADA.  COLD MID LEVEL TEMPERATURES WERE SHIFTING AWAY
FROM MICHIGAN AND WERE ACROSS EASTERN ONTARIO/QUEBEC AND THE LOWER
GREAT LAKES.  BROAD SURFACE LOW PRESSURE REFLECTING THE UPPER LEVEL
CIRCULATION WAS CENTERED JUST SOUTH OF JAMES BAY WITH A TRAILING
COLD FRONT ACROSS LAKE SUPERIOR/NORTHERN MINNESOTA...SO STILL SOME
LOW LEVEL COLD ADVECTION IMPLIED ACROSS THE UPPER LAKES DESPITE MID
LEVEL WARMING.

TROUGHING WILL LINGER ACROSS THE GREAT LAKES THROUGH THIS WEEKEND
AND INTO EARLY NEXT WEEK...THOUGH WEAKENING IN MAGNITUDE.  SO AT
LEAST TEMPERATURES WILL MODERATE THOUGH NO SUGGESTION OF ANY REAL
HEAT ANYTIME SOON.  SHORT WAVE ENERGY WILL CONTINUE TO SPILL INTO
THE MEAN TROUGH...THOUGH NO REAL SURFACE FEATURES TO SINK YOUR TEETH
INTO AS THE SURFACE PRESSURE PATTERN REMAINS PRETTY FLAT AND DEEP
LAYER CYCLONIC FLOW LOOSENS ITS GRIP.  A COUPLE OF SHORT WAVE
TROUGHS TO IMPACT MICHIGAN AND THE SURROUNDING REGION IN THE SHORT
TERM...ONE ON SATURDAY AND A SECOND LATER SUNDAY INTO EARLY
MONDAY...THE LATTER FEATURE WILL HAVE A WEAK SURFACE COLD FRONT
ASSOCIATED WITH IT THAT MAY ARRIVE IN THE MONDAY TIME FRAME.

PRIMARY FORECAST CONCERNS (NEAR TERM): PROBABLY ANOTHER COUPLE DAYS
OF POTENTIAL FOR DIURNALLY ENHANCED PRECIPITATION CHANCES...AIDED BY
LAKE BREEZE DEVELOPMENT.

NEAR TERM (FRIDAY/SATURDAY): FORECAST ISSUES FOR FRIDAY LOOK A LOT
LIKE THOSE OF THIS AFTERNOON...SOMEWHAT COOL AIR MASS AND JUST
ENOUGH BOUNDARY LAYER MOISTURE TO MAKE THINGS INTERESTING.  DEW
POINTS IN THE LOWER 50S SHOULD BE ENOUGH TO GENERATE A NARROW
INSTABILITY PROFILE AT LEAST ACROSS NORTHERN LOWER MICHIGAN.  LAKE
HURON BREEZE PRESSING INLAND WILL PROVIDE A POTENTIAL FOCUS FOR
CONVECTIVE DEVELOPMENT...THOUGH A BROAD AREA OF LOW LEVEL MOISTURE
CONVERGENCE IS DEPICTED ACROSS MUCH OF NORTHERN LOWER SO WILL HAVE A
RELATIVELY BROAD AREA OF SHOWER CHANCES FOR NORTH CENTRAL/NORTHEAST
LOWER (INLAND FROM LAKE MICHIGAN SHADOW).  EASTERN UPPER INSTABILITY
MAY BE A LITTLE MARGINAL SO WILL KEEP AREAS ABOVE THE BRIDGE DRY.
SHOWER THREAT EXPECTED TO WANE WITH LOSS OF HEATING FRIDAY EVENING.
STILL MAINLY 70S FOR HIGHS FRIDAY AFTERNOON.

SATURDAY MAY DAWN WITH A LITTLE PATCHY FOG...OTHERWISE SHOULD BE A
NICE START TO THE DAY WITH FORECAST ISSUES LIKELY FOCUSING ON THE
SAME THINGS WE`VE BEEN LOOKING AT THE PAST SEVERAL WHICH IS THE
LIKELIHOOD OF DIURNALLY DRIVEN SHOWERS.  NOT SURE THAT SHORT WAVE
TROUGH PASSAGE WILL HAVE MUCH OF AN IMPACT...AND BOUNDARY LAYER MAY
BE A LITTLE DRIER ON SATURDAY ESPECIALLY FARTHER NORTH.  SO ANY
SHOWER THREAT MAY END UP GETTING PUSHED TOWARD OR SOUTH OF THE M-72
CORRIDOR...AND LIKE FRIDAY LAKE BREEZE CONVERGENCE MAY BE A MAIN
PLAYER AS FAR AS FORCING IS CONCERNED.  SATURDAY HIGHS EXPECTED TO
BE WITHIN A COUPLE DEGREES EITHER SIDE OF AVERAGE (MID 70S TO AROUND
80).  ANOTHER SHORT WAVE TROUGH WILL PUSH IN FROM THE NORTHWEST
SATURDAY NIGHT ALONG WITH A WEAK COLD FRONT...BUT ANY IMPACTS FROM
THIS FEATURE WILL BE AN ISSUE FOR SUNDAY.

MEDIUM RANGE (SUNDAY/MONDAY/TUESDAY): AS MENTIONED ABOVE...LOOKING
AT ANOTHER SHORT WAVE TROUGH PASSAGE IN THE LATER SUNDAY/EARLY
MONDAY TIME FRAME...WHICH WILL ALSO HAVE A WEAK SURFACE REFLECTION
AND COLD FRONT ALONG WITH IT.  THIS BOUNDARY MAY END UP STALLING
SOUTH OF MICHIGAN BY TUESDAY AS IT BEGINS TO PARALLEL THE UPPER
LEVEL FLOW.  AS LONG AS IT CAN PUSH FAR ENOUGH SOUTH TUESDAY SHOULD
BE DRY.  NARROW BAND OF MOISTURE ALONG THE FRONT MAY BRING SOME
SHOWERS TO NORTHERN MICHIGAN FROM WEST TO EAST AS SUNDAY
PROGRESSES...POSSIBLY DRYING OUT MONDAY TO SOME DEGREE BUT UNCERTAIN
ON FRONTAL TIMING WHICH WILL BE PROBLEMATIC ESPECIALLY SOUTH OF THE
BRIDGE.  NO CHANGES YET TO A DRY TUESDAY FORECAST.

OUTLOOK (WEDNESDAY/THURSDAY):  MIDWEEK PERIOD MAY SEE BOUNDARY TRY
TO PUSH BACK NORTH AS IT INTERACTS WITH NEW SHORT WAVE ENERGY...BUT
EXACT EVOLUTION AND WHETHER THIS FRONT LIFTS FAR ENOUGH NORTH TO
IMPACT NORTHERN MICHIGAN IS UNKNOWN THIS FAR OUT...AND WILL CHANGE
WITH EACH ITERATION OF THE GUIDANCE GOING FORWARD.  SO EITHER
WEDNESDAY OR THURSDAY (OR BOTH) COULD HAVE SOME WET PERIODS SO WILL
TREND FORECAST IN THAT DIRECTION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1151 PM EDT THU JUL 31 2014

GROUND FOG OVERNIGHT PLN/MBL. OTHERWISE VFR.

WEAK LOW PRESSURE JUST SOUTH OF JAMES BAY WILL MOVE NE AWAY FROM
THE REGION. THAT WILL LEAVE BROAD...WEAK HIGH PRESSURE IN CONTROL.
SOME FOG IS EXPECTED AGAIN TONIGHT AT FOG-PRONE MBL/PLN. BRIEF
INCURSIONS OF IFR ARE POSSIBLE...BUT FOR NOW WILL JUST TEMPO IN
SEVERAL HOURS OF MVFR VERY LATE TONIGHT.

LIGHT WINDS TONIGHT...LAKE BREEZES BY FRIDAY AFTERNOON.

&&

.MARINE...
ISSUED AT 334 PM EDT THU JUL 31 2014

WEAK LOW PRESSURE DISPLACED WELL NORTHEAST OF MICHIGAN WILL KEEP THE
PRESSURE GRADIENT WEAK ACROSS THE UPPER GREAT LAKES THROUGH
SATURDAY.  SO NOT A LOT OF MARINE CONCERNS NOTED THROUGH SATURDAY
OUTSIDE OF LAKE BREEZE DEVELOPMENT IMPACTING LOCAL WIND VELOCITIES.


&&

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

&&

$$

UPDATE...JZ
SYNOPSIS...ALM
SHORT TERM...LAWRENCE
LONG TERM...JPB
AVIATION...JZ
MARINE...JPB