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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
416 AM EDT WED AUG 20 2014

.SYNOPSIS...
ISSUED AT 413 AM EDT WED AUG 20 2014

UPPER LEVEL LOW PRESSURE WILL MEANDER ACROSS THE AREA TODAY...PROVIDING
NORTHERN MICHIGAN WITH A FEW MORE SHOWERS AND THUNDERSTORMS INTO
THE EVENING HOURS. THIS SYSTEM WILL DEPART TONIGHT...ALLOWING HIGH
PRESSURE TO BRIEFLY RETURN WITH DRY WEATHER ON THURSDAY. ADDITIONAL
SMALL CHANCES FOR SHOWERS AND STORMS WILL RETURN FRIDAY AND THROUGH
THE WEEKEND...AS A WARM FRONT SLOWLY LIFTS NORTH THROUGH THE GREAT
LAKES.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 413 AM EDT WED AUG 20 2014

...MAINLY CLOUDY TODAY WITH SCATTERED TO NUMEROUS SHOWERS...

HIGH IMPACT WEATHER POTENTIAL: LOCALLY DENSE FOG EARLY THIS MORNING...
MORE RAIN THIS AFTERNOON WITH LOCALLY HEAVY DOWNPOURS.

PATTERN SYNOPSIS/FORECAST: MIDNIGHT SURFACE/COMPOSITE ANALYSIS SHOWS 
A DEEP/STACKED CYCLONIC CIRCULATION CENTERED OVER WESTERN UPPER 
MICHIGAN...1005MB SURFACE LOW OVER NORTHERN LAKE MICHIGAN WITH AN 
EAST-WEST FRONT RUNNING THROUGH THE CENTER OF THE LOW ACROSS 
NORTHERN LAKE HURON AND EXTENDING SOUTHEAST INTO THE LOWER GREAT 
LAKES...ANOTHER TROUGH/COLD FRONT EXTENDS SOUTH FROM THE LOW DOWN 
THE AXIS OF LAKE MICHIGAN INTO NORTHERN ILLINOIS.  LOW LEVEL WARM 
ADVECTION EAST OF THE LOW SUPPORTING SHOWERS ACROSS THE NORTH 
CHANNEL AND INTO NORTHEAST ONTARIO...LOW LEVEL COLD ADVECTION ACROSS 
WESTERN UPPER MICHIGAN/NORTHERN WISCONSIN CONTRIBUTING TO A DEARTH 
OF PRECIPITATION ACROSS MUCH OF UPPER/NORTHERN LOWER MICHIGAN EARLY 
THIS MORNING.  WATER VAPOR IMAGERY SHOWS A NUMBER OF SMALL VORTICITY 
CENTERS SPINNING AROUND THE PERIPHERY OF THE CIRCULATION...NARROW 
AXIS OF MID LEVEL DRY AIR HAS SPREAD ACROSS THE FORECAST AREA THOUGH 
PRECIPITABLE WATER STILL IN THE 1.25-1.50 INCH RANGE.  

DEEP LAYER CYCLONE WILL CONTINUE TO INCH EASTWARD THROUGH TONIGHT
ACROSS MICHIGAN...ALONG WITH CONTINUED DEEP LAYER MOISTURE AND THE 
PLETHORA OF VORTICITY CENTERS ROTATING AROUND THE MAIN CYCLONIC 
CENTER.  

PRIMARY FORECAST CONCERNS: CONTINUED PRECIPITATION CHANCES...WHICH 
SHOULD HAVE A MOSTLY DIURNAL COMPONENT TO THEM. POTENTIAL FOR 
ADDITIONAL STRATUS AND FOG TONIGHT.

TODAY/TONIGHT...WIDESPREAD CLOUDS ACROSS NORTHERN MICHIGAN EARLY 
THIS MORNING...SCATTERED SHOWERS ARE MOVING ACROSS NORTHERN LOWER 
AHEAD OF THE LAKE MICHIGAN SURFACE TROUGH/COLD FRONT.  SOME FOG HAS 
BEEN DEVELOPING AS WELL...A LITTLE THICKER ACROSS THE HIGHER TERRAIN 
WHERE STRATUS IS INTERSECTING THE HILLTOPS.  THINK PRECIPITATION 
TODAY WILL START OUT SCATTERED THIS MORNING AHEAD OF THE EASTWARD 
ADVANCING BOUNDARY AND THE UPPER LOW ITSELF.  ALTHOUGH CLOUDS WILL 
HANG ON MOST AREAS DURING THE DAY...COOLING ALOFT AND EVEN JUST SOME 
MODEST HEATING SHOULD GENERATE A BIT OF INSTABILITY THIS AFTERNOON 
ESPECIALLY ACROSS NORTHERN LOWER.  SO POSSIBILITY FOR AN EXPANSION 
IN PRECIPITATION COVERAGE ACROSS NORTH CENTRAL/NORTHEAST LOWER AS 
THE DAY WEARS ON.  LOCALLY HEAVY RAINFALL WILL BE AN ISSUE GIVEN 
DECENT MOISTURE CONTENT/NARROW CAPE PROFILE AND SLOW MOVEMENT OF 
STORMS.  ALSO EXPECTING A MINIMUM IN PRECIPITATION ACROSS NORTHWEST 
LOWER...WITH OVERALL DIMINISHING OF THE PRECIPITATION THREAT THIS 
EVENING (AND SHOULD SEE ANOTHER ROUND OF STRATUS/FOG DEVELOP 
TONIGHT).

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 413 AM EDT WED AUG 20 2014

...TYPICAL LATE AUGUST WEATHER RETURNS...

HIGH IMPACT WEATHER POTENTIAL: SEVERAL CHANCES FOR THUNDERSTORMS...
PRIMARILY THURSDAY NIGHT ON INTO THE WEEKEND. SEVERE STORMS NOT 
LOOKING TOO LIKELY AT THIS POINT...BUT LOCALIZED HEAVY RAINS 
POSSIBLE. 

PATTERN SUMMARY: A PATTERN NOT SEEN VERY MUCH THIS SUMMER SHOULD 
TAKE SHAPE THROUGH LATE WEEK AND THE WEEKEND...CONSISTING OF 
AMPLIFIED WESTERN TROUGHING AND A DOWNSTREAM RIDGE AMPLIFICATION 
RIGHT ON INTO THE GREAT LAKES. THIS FEATURE WILL GET SQUEEZED WEST 
OF RESIDUAL UPPER TROUGHING OVER NEW ENGLAND...WHILE A COUPLE OF 
WEAKER HARD TO TIME SHORTWAVE RIDE THE NORTHERN PERIPHERY OF THE 
MEAN RIDGE AXIS. AT THE SURFACE...A WARM FRONT OF SORTS (DELINEATION 
BETWEEN THE TRUE SUMMERTIME HEAT/HUMIDITY/INSTABILITY AND MORE 
NORTHERN STREAM INFLUENCED "COOLER" CONDITIONS) IS EXPECTED TO WAVER 
SOMEWHERE NEARBY...WITH SIMPLE PATTERN RECOGNITION OF THE OVERALL 
UPPER FLOW SUGGESTIVE THAT SEVERAL CONVECTIVE COMPLEXES MAY TEASE 
NORTHERN MICHIGAN AT VARIOUS TIMES. AT SOME POINT NEXT WEEK...THE 
WESTERN TROUGH IS EXPECTED TO EASE EASTWARD...SENDING A COLD FRONT 
IN OUR DIRECTION DURING THE FIRST PART OF THE WORK WEEK. HOWEVER...
CONFIDENCE ON TIMING OF THIS FEATURE IS FAR FROM HIGH AT THIS POINT 
IN TIME.

A LOOK AT THE FORECAST DETAILS...

THURSDAY-FRIDAY NIGHT: NOT EXACTLY THE HIGHER CONFIDENCE I WOULD 
LIKE THIS FAR IN...WITH PLENTY OF QUESTION REVOLVING AROUND JUST HOW 
FAR NORTH CONVECTION WILL MAKE IT. SIMPLE MECHANISM OF BUILDING 
LOW/MID LEVEL RIDGING WILL NUDGE A RATHER TIGHT THERMAL/THETA-E 
GRADIENT NORTHWARD THROUGH THE WESTERN LAKES WITH TIME...WITH THIS 
FEATURE TRYING DESPERATELY TO LIFT INTO PARTS OF CENTRAL MICHIGAN BY 
FRIDAY. AS WAS DISCUSSED SEVERAL DAYS AGO...THURSDAY ITSELF MAY WELL 
TURN OUT TO BE DRY FOR MOST LOCATIONS...AS A NOTABLE INFLUX OF DRIER 
LOW LEVEL AIR ENTERS THE PICTURE COURTESY OF WEAK NORTHERLY FLOW ON 
THE BACKSIDE OF THE DEPARTING UPPER TROUGH. CURRENT FORECAST HAS A 
SLIVER OF LOW POPS ACROSS SOUTHERN COUNTIES...AND THAT MAY WORK WELL 
WITH WEAKISH LOW LEVEL THETA-E ADVECTION KICKING IN DOWN THAT WAY 
THROUGH THE LATE DAY. 

HAVE TO HONESTLY SAY THAT I'M NOT TERRIBLY THRILLED BY CHANCES FOR 
PRECIP THEREAFTER AS THE SETUP JUST DOESN'T SCREAM FOR RAIN ACROSS 
NORTHERN MICHIGAN. FOR ONE...THE UPPER RIDGE LOOKS FLATTER THAN 
DESIRED...FAVORING NOCTURNAL CRANKING OF THE LOW LEVEL JET NOSE TO 
OUR SOUTH...WHILE WE ALSO SIT ON THE SLACKER SIDE OF THE 
MOISTURE/HEAT/INSTABILITY GRADIENT LIKELY TO RESIDE OVER THE MID 
MISSISSIPPI VALLEY...SOUTHERN LAKES...AND OHIO VALLEY. IN 
ADDITION...REPEATED ROUNDS OF CONVECTION ALONG THE LOW LEVEL 
BOUNDARY JUST TO OUR SOUTH WON'T DO ANYTHING TO LIFT IT NORTH IN THE 
FACE OF ANY LACKING STRONGER UPPER WAVES TO OUR WEST...SUGGESTING A 
MUCH MORE CLIMO-FAVORED POSITION FOR CONVECTION RESIDING THROUGH THE 
LOWER LAKES...SOME OF WHICH MAY BE A BIT BEEFY GIVEN THE DEGREE OF 
HEAT/INSTABILITY AND STRONGER JET DYNAMICS POTENTIALLY IN PLAY AT 
TIMES. THE GFS ENSEMBLE MEAN PRECIP PLOTS HAVE BEEN ALL OVER THIS 
IDEA FOR DAYS...SUGGESTING OUR FORECAST IS PROBABLY WAY TOO WET FOR 
MOST PERIODS. GIVEN THE REMAINING UNCERTAINTY (THIS IS CONVECTION 
WE'RE TALKING ABOUT AFTER ALL)...DO HAVE TO KEEP AT LEAST A SMALLER 
CHANCE MENTION THROUGH LATE WEEK...WITH THE BEST CHANCES (IF YOU CAN 
CALL THEM THAT) RESIDING OVER SOUTHWEST COUNTIES SOUTH OF GRAND 
TRAVERSE BAY. 

SATURDAY-SUNDAY NIGHT: PERHAPS A BETTER CHANCE FOR SHOWERS AND 
STORMS AS WE PUSH INTO THE WEEKEND...AS THE WESTERN TROUGH EMERGES 
ONTO THE NORTHERN PLAINS...HELPING FURTHER AMPLIFY THE UPPER RIDGE 
THROUGH THE GREAT LAKES. THAT SETUP SHOULD ATTEMPT TO LIFT AN 
ELEVATED WARM FRONT THROUGH OUR REGION SOMETIME AROUND SATURDAY OR 
SATURDAY NIGHT (TIMING STILL IN QUESTION)...WITH RESULTANT BETTER 
RAIN CHANCES ALONG THAT FEATURE. SAID ELEVATED WARM FRONT SHOULD 
LIFT THROUGH ONTARIO BY SUNDAY...ALLOWING FOR AT LEAST POTENTIAL FOR 
SOME REAL AUGUST HEAT AS STRONGER THERMAL RIDGING (H8 TEMPS AROUND 
16-18C PER CONSENSUS) BRIEFLY BUILDS INTO OUR NECK OF THE WOODS. OF 
COURSE...ONE POORLY PLACED ROUND OF RAIN WOULD EASILY SPOIL THE 
FUN...BUT FOR THE WARM WEATHER FOLKS...THIS ONE AT LEAST HAS SOME 
PROMISE.

MONDAY-TUESDAY: CONTINUED UNCERTAINTY AS THE UPPER PATTERN AGAIN 
ATTEMPTS TO UNDERGO TRANSITION. AT SOME POINT...THE TROUGH AXIS 
ACROSS THE NORTHERN PLAINS WILL GET PUNTED EASTWARD...DRIVING A 
ROUND LOWERING HEIGHTS THROUGH THE GREAT LAKES AND ALSO LIKELY 
FORCING THE ARRIVAL OF A COLD FRONT SOMETIME AROUND MONDAY NIGHT OR 
TUESDAY...AT LEAST BASED ON CURRENT TIMING. SAID UPPER TROUGH WILL 
BE NOSING INTO A STRONGLY RIDGED ENVIRONMENT...AND SUSPECT SOME 
FURTHER SLOWDOWNS ARE IMMINENT WITH REGARD TO THE FRONTAL PASSAGE 
TIMING. NONETHELESS...ADDITIONAL CHANCES FOR SHOWERS AND STORMS 
SHOULD BE FOUND DURING THIS STRETCH BEFORE PERHAPS ANOTHER ROUND OF 
COOLER WEATHER ROLLS IN TOWARD MIDWEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1151 PM EDT TUE AUG 19 2014

CONDITIONS DETERIORATING TO IFR TONIGHT...SLOWLY IMPROVING TO MVFR
WEDNESDAY. 

LOW PRESSURE WILL WEAKEN AS IT DRIFTS EAST FROM NORTHERN LAKE MI
TO EASTERN LOWER MI DURING THE TAF PERIOD. THE WX WILL REMAIN
UNSETTLED...WITH PERIODIC CHANCES FOR SHRA AND PERHAPS A TSRA.
THE BEST CHANCE FOR THESE WILL CENTER ON WEDNESDAY AFTERNOON. THE
MAIN STORY FOR TONIGHT IS AN INTRUSION OF DRY AIR ALOFT...ALLOWING
FOR A PERIOD OF PARTIAL CLEARING. THE LOW LEVELS REMAIN MOIST...
AND FOG/STATUS IS STILL EXPECTED LATE TONIGHT. COMPARED TO THE
PREVIOUS TAF ISSUANCE...THE PRIMARY FOCUS WILL BE MORE IN THE WAY
OF STRATUS...AND LESS IN THE WAY OF FOG.

LIGHT WINDS THRU THE FORECAST.

&&

.MARINE...
ISSUED AT 413 AM EDT WED AUG 20 2014

WEAK LOW PRESSURE WILL MEANDER OVER THE WATERS TODAY...YIELDING A 
WEAK PRESSURE GRADIENT AND LIGHT WINDS MAINLY 10 KNOTS OR LESS...
OUTSIDE OF A FEW SHOWERS OR THUNDERSTORMS THAT DEVELOP THROUGH THE 
DAY. WEAK HIGH PRESSURE WILL TAKE OVER TONIGHT INTO THURSDAY...WITH 
CONTINUED LIGHT WINDS AND LOW WAVES...WITH A SIMILAR SLACK PRESSURE 
GRADIENT DELIVERING AN EXTENDED STRETCH OF WINDS 15 KNOTS OR LESS 
RIGHT ON THROUGH THE WEEKEND. 

&&

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

&&

$$

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

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