000
FXUS63 KAPX 120535
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
135 AM EDT SAT JUL 12 2014

.SYNOPSIS...
ISSUED AT 407 PM EDT FRI JUL 11 2014

A WEAK DISTURBANCE APPROACHING AND PASSING THROUGH THE NORTHERN
LAKES WILL BRING THE RISK FOR A FEW SHOWERS AND POSSIBLE
THUNDERSTORMS LATER TONIGHT... CONTINUING THROUGH THE WEEKEND. A
PERIOD OF UNSEASONABLY CHILLY AND UNSETTLED CONDITIONS IS EXPECTED
HEADING INTO THE START OF NEXT WORK WEEK.

&&

.UPDATE...
ISSUED AT 1002 PM EDT FRI JUL 11 2014

SHORTWAVE SLIDING EAST OF THE AREA AND SCATTERED LIGHT
SHOWERS/SPRINKLES EXITING THE REGION. STILL A FEW RETURNS PERCOLATING
OVER EASTERN UPPER WITHIN 850MB THETA-E GRADIENT AND MORE
FAVORABLE KINEMATICS. THIS MAY CONTINUE FOR MUCH OF THE NIGHT...WITH A
UPTICK IN THE ACTIVITY POSSIBLE OVER EASTERN UPPER TOWARD SUNRISE
AS DEEPER MOISTURE WORKS INTO THE AREA FROM THE WEST WITH THE ARRIVAL
OF ADDITIONAL UPPER SUPPORT. A MILD NIGHT BY RECENT STANDARDS WITH
LOWS GENERALLY IN THE UPPER 50S TO LOWER 60S.

UPDATE ISSUED AT 659 PM EDT FRI JUL 11 2014

WEAK SHORTWAVE ENERGY SLIDING ACROSS NORTHERN MICHIGAN EARLY THIS
EVENING WITH JUST ENOUGH JET FORCING TO PRODUCE SOME LIGHT
SHOWERS/SPRINKLES. GIVEN TEMP/DWPT SPREADS OF 15-25 DEGF IN SOME
AREAS...PRECIPITATION QUITE LIGHT. WILL SPREAD PRECIPITATION
MENTION FURTHER SOUTH INTO NORTHERN LOWER THIS EVENING
/SPRINKLES/. THERE MAY NOT BE MUCH HAPPENING LATER THIS EVENING
BEHIND THIS INITIAL WAVE...WITH INCREASED ACTIVITY LATE TONIGHT
AS RIBBON OF HIGHER THETA-E AIR GRADUALLY WRAPS INTO THE AREA FROM
THE WEST.

WILL LEAVE THUNDERSTORM WORDING IN FOR EASTERN UPPER...ALTHOUGH
INSTABILITY IS LESS THAN IMPRESSIVE /BUT STILL SOME FAVORABLE
KINEMATICS/.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 407 PM EDT FRI JUL 11 2014

CURRENTLY...IN BETWEEN A 1024MB HIGH PRESSURE CENTERED OVER THE
NORTHEAST UNITED STATES AND A LOW PRESSURE SYSTEM TO THE WEST OF
HUDSON BAY...PRODUCING A SOMEWHAT DRY SOUTHWESTERLY WIND FLOW. AN
AREA OF ELEVATED RADAR RETURNS IS MOVING EASTWARD ACROSS CENTRAL
UPPER MOVING INTO DEW POINT DEPRESSIONS OF 20 DEGREES FAHRENHEIT OVER
EASTERN UPPER...DIMINISHING CHANCES OF PRECIPITATION. BEST AREA OF
LOW-LEVEL MOISTURE IS CURRENTLY OVER SOUTHERN WISCONSIN...AND ALONG
WITH SOME INSTABILITY ASSOCIATED WITH A SHORTWAVE TROUGH OVER THE
WESTERN GREAT LAKES REGION IS PRODUCING LIGHT TO MODERATE RAIN
SHOWERS.

REST OF TODAY...AFOREMENTIONED SHORTWAVE TRAVERSES OVER THE NORTHERN
GREAT LAKES THIS AFTERNOON/EVENING...BUT WITH LOW-LEVEL MOISTURE
AXIS STAYING WELL WEST ANY RAIN CHANCES ARE VERY LOW. BEST CHANCES
WILL BE OVER EASTERN UPPER AND THE TIP OF THE MITT...AS ANOTHER
SMALL RIBBON OF MOISTURE MOVES OVER SAID LOCATIONS. STILL THINK
CHANCES ARE VERY LOW DUE TO DRY LOW-LEVELS AND IF ANYTHING DOES
DEVELOP IT WILL BE VERY LIGHT SHOWERS/SPRINKLES.

TONIGHT...MOISTURE AXIS FINALLY ARRIVES OVER NORTHERN MICHIGAN ALONG
WITH UPPER LEVEL JET AXIS DIPPING FROM WESTERN UPPER INTO NORTHERN
LOWER. ALTHOUGH MOST INSTABILITY EXITED EAST WITH AFOREMENTIONED
SHORTWAVE...THIS JET SETUP WILL LEAVE THE BEST CHANCES FOR
PRECIPITATION/THUNDER OVER EASTERN UPPER AS THEY ARE UNDER THE LEFT
EXIT REGION OF THE UPPER JET. MOST ACTION WILL OCCUR WEST OF HERE
WHERE THE LOW LEVEL JET AND INSTABILITY WILL BE BEST. WILL LEAVE
PRECIPITATION CHANCES IN THE FORECAST...BUT SLOW THE TIMING BY A
COUPLE HOURS. LOW TEMPERATURES UPSTREAM THIS MORNING WAS IN THE LOW
TO MID 60S. WITH TEMPERATURES IN THE MID TO UPPER 70S THIS AFTERNOON
AND FORECAST CLOUD COVER...RAISED NIGHT TIME TEMPERATURES JUST A
COUPLE DEGREES TO AGREE WITH UPSTREAM OBSERVATIONS THIS MORNING AND
TRENDING MODEL THOUGHTS.

.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 407 PM EDT FRI JUL 11 2014

...INCREASING RAIN CHANCES ESPECIALLY SATURDAY NIGHT/MUCH COOLER
EARLY NEXT WEEK...

HIGH IMPACT WEATHER POTENTIAL: SOME THUNDERSTORMS POSSIBLE SATURDAY
AND ESPECIALLY NORTHERN LOWER SATURDAY NIGHT.  ANOMALOUS CHILL FOR
TUESDAY.

PATTERN SYNOPSIS/FORECAST: EVOLVING FIVE WAVE HEMISPHERIC PATTERN
WITH A TROUGH-RIDGE-TROUGH PATTERN FROM THE NORTHEAST PACIFIC-
WESTERN NORTH AMERICA-EASTERN NORTH AMERICA.  REMNANTS OF TROPICAL
CYCLONE "NEOGURI" PULLING AWAY FROM JAPAN AND INTO THE NORTHWEST
PACIFIC.  SHORT WAVE PATTERN SHOWS A NICE WAVE TRAIN ACROSS CANADA
WITH TROUGHS OVER ATLANTIC CANADA AND MANITOBA...AND A LARGE UPPER
LOW OVER THE ALEUTIANS.  SHORT WAVE RIDGING ACROSS THE UPPER GREAT
LAKES INTO NORTHERN ONTARIO...AND UP INTO BRITISH COLUMBIA/YUKON
WHICH IS HELPING PUSH A HIGH LATITUDE SHORT WAVE SOUTHWARD FROM
ABOVE THE ARCTIC CIRCLE AND TOWARD THE SHORT WAVE TROUGH OVER
MANITOBA.  SO ALL THE PLAYERS ARE ON THE FIELD...SO TO SPEAK...FOR
SIGNIFICANT PATTERN EVOLUTION HEADING INTO NEXT WEEK.  WATER VAPOR
IMAGERY ALSO SHOWS A WELL DEFINED VORTICITY CENTER LIFTING NORTHWARD
THROUGH THE GREAT BASIN...WHICH MAY HAVE AN IMPACT ON LOCAL WEATHER
THIS WEEKEND.  SURFACE ANALYSIS SHOWS A COLD FRONT ASSOCIATED WITH
MANITOBA SHORT WAVE TROUGH EXTENDING SOUTHWARD FROM A SURFACE LOW
OVER FAR NORTHERN MANITOBA INTO THE DAKOTAS/SOUTHERN MONTANA/IDAHO
PANHANDLE.  AXIS OF 60+F DEW POINTS EXTENDS ACROSS THE PLAINS/
MIDWEST AND ALONG THE MANITOBA/ONTARIO BORDER AHEAD OF THE
BOUNDARY...NARROW RIDGE OF DRIER AIR EXTENDS INTO LOWER MICHIGAN
FROM THE NORTHEAST.  HIGH PRESSURE ENCOMPASSED THE LOWER GREAT
LAKES...OLD WARM FRONT EXTENDS FROM EASTERN COLORADO SOUTHEAST INTO
THE LOWER MISSISSIPPI VALLEY.

MERGING MANITOBA AND ARCTIC UPPER LEVEL ENERGY EXPECTED TO RESULT IN
A VERY ANOMALOUS LOW TO DEVELOP OVER CENTRAL CANADA THIS WEEKEND
(2-3 STANDARD DEVIATIONS BELOW THE MEAN)...WHICH THEN SPILLS SOUTH
INTO THE NORTHERN PLAINS/UPPER MIDWEST SUNDAY (AT 3+ STANDARD
DEVIATIONS BELOW THE MEAN).  LEAD COLD FRONT OVER THE DAKOTAS TODAY
WILL GET STRETCHED NORTHEAST-SOUTHWEST AS IT TRIES TO PUSH INTO THE
UPPER GREAT LAKES...WHILE PLAINS WARM FRONT LIFTS NORTHWARD INTO THE
MIDWEST.  HEIGHT FALLS ASSOCIATED WITH MANITOBA VORTEX WILL BEGIN TO
SPREAD INTO THE UPPER MIDWEST SATURDAY...WITH SECONDARY COLD FRONT
INTO THE UPPER GREAT LAKES FOR SUNDAY.  CORE OF THE HEIGHT/THERMAL
TROUGH WILL DROP INTO THE UPPER MIDWEST/WISCONSIN MONDAY.

PRIMARY FORECAST CONCERNS (NEAR TERM): VARYING PRECIPITATION CHANCES
THROUGH THE WEEKEND.

NEAR TERM (SATURDAY/SUNDAY): APPROACHING COLD FRONT WILL HAVE A
DIFFICULT TIME PUSHING ACROSS THE UPPER PENINSULA...BUT LOW LEVEL
MOISTURE/THETA-E AXIS WILL GET "TIPPED" TOWARD NORTHERN MICHIGAN
WITH INCREASING ADVECTION ACROSS THE FORECAST AREA.  INITIAL
COVERAGE WILL BE SOMEWHAT SCATTERED DURING THE MORNING ACROSS
EASTERN UPPER/NORTHWEST LOWER WITH NORTHERN MICHIGAN UNDER RIGHT
EXIT (CONVERGENT) REGION OF THE JET AXIS...WHILE LIKELY WATCH SOME
MCS REMNANTS PASS BY WELL TO THE SOUTH.  BY AFTERNOON...LOW LEVEL
THETA-E AXIS WILL LIE ACROSS NORTHERN MICHIGAN...AND WILL BEGIN TO
GET BENEATH MORE FAVORABLE JET DYNAMICS AS HEIGHT FALLS DROP INTO
THE MIDWEST.  ANY HEATING WE CAN GENERATE WON`T HURT THE CAUSE...
SEEMS MORE LIKELY OVER NORTHEAST LOWER AS THERE MAY BE A GOOD BIT OF
CLOUD COVER AHEAD OF THE WEAKENING FRONTAL BOUNDARY.  BUT ANOTHER
HELPFUL FACTOR MAY BE IN THE FORM OF THE GREAT BASIN VORTICITY
MAXIMUM WHICH IS FORECAST TO GET DRAWN EASTWARD TONIGHT AND
EVENTUALLY ARRIVE OVER LOWER MICHIGAN LATE IN THE DAY.  MODEST LAKE
BREEZE CONVERGENCE MAY ALSO HELP THINGS ALONG NEAR LAKE HURON AND
WHITEFISH BAY.  SO EXPECT AN UPTICK IN CONVECTIVE COVERAGE ACROSS
WISCONSIN/IOWA/NORTHERN ILLINOIS AND LOWER MICHIGAN LATER IN THE DAY
AND LEADING INTO SATURDAY EVENING.  PLAN TO INCREASE PRECIPITATION
PROBABILITIES ACROSS NORTHERN LOWER MICHIGAN IN RESPONSE SATURDAY
AFTERNOON AND INTO SATURDAY NIGHT.  SOME CONCERN FOR HEAVY RAINFALL
POTENTIAL DEPENDING ON WHERE CONVECTION SETS UP...RIGHT NOW THINK
GREATER THREAT IS ACROSS SOUTHERN LOWER BUT IF THINGS DEVELOP A
LITTLE FARTHER NORTH COULD SEE SOME GOOD RAINS GETTING INTO THE M-55
CORRIDOR.

SUNDAY FORECAST IS A BIT MORE AMBIVALENT IN THAT SATURDAY NIGHT
PRECIPITATION SHOULD BE EAST OF THE AREA BY MORNING...WHILE HEIGHT
FALLS CONTINUE TO PRESS INTO MICHIGAN FROM THE NORTHWEST ALONG WITH
SECONDARY COLD FRONT.  WHILE THINGS ARE EXPECTED TO DRY OUT
OVERALL...ARRIVAL OF BETTER DYNAMICS AND COOLER TEMPERATURES ALOFT
AND SOME LINGERING BOUNDARY LAYER MOISTURE MAY ALLOW FOR SOME
SHOWERS TO DEVELOP ESPECIALLY WITH SOME HEATING.  SO RELUCTANT TO
DOWNPLAY PRECIP CHANCES FOR SUNDAY THOUGH FORECAST SOUNDINGS ARE NOT
TERRIBLY IMPRESSIVE DESPITE GUIDANCE TRYING TO SQUEEZE OUT SOME
QPF.  WILL PROBABLY SEE SOME MORNING LOW CLOUDS MIX INTO A CU
DECK...SO SUNDAY MAY NOT TURN OUT TO BE TOO BAD OF A DAY THOUGH WILL
BE COOLER THAN SATURDAY ESPECIALLY THE FARTHER NORTH ONE GOES.  DRY
SUNDAY NIGHT AS COOLER/DRIER AIR FILTERS IN.

MEDIUM RANGE (MONDAY/TUESDAY/WEDNESDAY): COOLER AIR WILL ALREADY BE
SPILLING INTO MICHIGAN SUNDAY...SO THE EARLY PART OF THE WEEK WILL
BE A CONTINUATION OF THIS AS THE HEART OF THE COLDEST AIR MOVES INTO
THE UPPER MIDWEST MONDAY.  STILL PREFER THE IDEA OF INSTABILITY
SHOWERS MONDAY AFTERNOON...WHICH WILL CONTINUE SWIRLING ABOUT
TUESDAY AS LOWEST HEIGHTS DRAG THROUGH THE GREAT LAKES WITH PLENTY
OF CLOUDS AND LIKELY PLENTY OF HIGH TEMPERATURES IN THE 50S AS A
RESULT.  COULD WE EVEN BE DEALING WITH SOME LAKE INSTABILITY HEADING
INTO TUESDAY NIGHT/WEDNESDAY?  THINGS EXPECTED TO START MODERATING
BY MIDWEEK.

OUTLOOK (THURSDAY/FRIDAY): DRY WITH A WARMING TREND AS UPPER TROUGH
CONTINUES TO DEPART.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 133 AM EDT SAT JUL 12 2014

VFR CONDITIONS EXPECTED TO CONTINUE FOR MUCH OF THE DAY
DESPITE MOISTENING LOW LEVEL AIRMASS. WILL NEED TO WATCH FOR
INCREASING SHOWER AND STORM POTENTIAL...ESPECIALLY NORTHEAST LOWER
(KAPN) LATER THIS AFTERNOON AS AIRMASS DESTABILIZES. BETTER
POTENTIAL FOR MORE WIDESPREAD SHOWERS AND STORMS ARRIVES VERY LATE
TODAY INTO THIS EVENING AS A DISTURBANCES MOVES THROUGH THE REGION.
MVFR CONDITIONS POSSIBLE DURING THIS TIME...WITH PERIODS OF VIS
RESTRICTION IN BRIEF HEAVY RAIN. CONFIDENCE ON HOW THIS ALL UNFOLDS
REMAINS VERY LOW...AND SIMPLY TO LOW TO SHOW THIS TYPE OF
SPECIFICITY WITHIN THIS TAF CYCLE. WILL CONTINUE TO RUN WITH VCSH
WORDING AND VFR CONDITIONS FOR NOW...LEAVING PLENTY OF TIME TO
EVALUATE CONVECTIVE TRENDS AS WE HEAD THROUGH LATER THIS
MORNING.

&&

.MARINE...
ISSUED AT 407 PM EDT FRI JUL 11 2014

SOUTHWEST GRADIENT WIND CONTINUES INTO SATURDAY THOUGH WINDS MAY GET
PULLED MORE ONSHORE NEAR THE NORTHEAST LOWER LAKE HURON NEARSHORE
ZONES AND POSSIBLY ALONG WHITEFISH BAY AS WELL.  INCREASING DEW
POINTS SHOULD ALSO BEGIN TO LEAD TO A REDUCTION IN VISIBILITIES DUE
TO ADVECTION FOG INITIALLY ON LAKE MICHIGAN SATURDAY AFTERNOON...AND
INTO WHITEFISH BAY AND NORTHERN LAKE HURON INTO SATURDAY NIGHT AND
THE FIRST HALF OF SUNDAY.  PASSAGE OF A COLD FRONT SUNDAY SHOULD
BEGIN TO IMPROVE VISIBILITIES AS WELL AS SWITCH WINDS AROUND TO THE
WEST AND NORTHWEST...THOUGH SHOULD BE AT SPEEDS BELOW SMALL CRAFT
ADVISORY CRITERIA.

&&

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

&&

$$

UPDATE...JK
SYNOPSIS...AM
SHORT TERM...TL
LONG TERM...JPB
AVIATION...MSB
MARINE...JPB