Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 231733
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
133 PM EDT SAT AUG 23 2014

.SYNOPSIS...
ISSUED AT 246 AM EDT SAT AUG 23 2014

HIGH PRESSURE TO OUR EAST WILL PROVIDE FOR LIGHT SOUTHERLY
BREEZES...AND INCREASING WARMTH AND HUMIDITY THROUGH MONDAY. FOR
THE MOST PART THE WEEKEND LOOKS DRY...BUT SHOWERS AND THUNDERSTORM
CHANCES WILL INCREASE ON MONDAY...AHEAD OF A WEAK COLD FRONT
THAT WILL ENTER NORTHERN MICHIGAN MONDAY NIGHT.

&&

.UPDATE...
ISSUED AT 1111 AM EDT SAT AUG 23 2014

SHARP MID LEVEL RIDGE AXIS CONTINUES TO POKE UP INTO THE WESTERN
GREAT LAKES...DOWNSTREAM OF STRONG SHORT WAVE TROUGHING ACROSS THE
NRN ROCKIES INTO THE NRN PLAINS. BROAD LOW PRESSURE ACROSS THE
CENTRAL PLAINS WITH A SFC WARM FRONT DRAPED ACROSS THE MIDWEST
INTO THE OHIO VALLEY...AND CONTINUES TO BE THE MAIN WEATHER FOCUS
WITH YET ANOTHER ROUND OF CONVECTION IN THE MIDWEST.

ACROSS NRN MICHIGAN...A BUNCH OF LITTLE THINGS HAPPENING. WEAK
HIGH PRESSURE IS DRAPED ACROSS NRN MICHIGAN. BUT...SUBTLE LOW-MID
LEVEL TROUGH AXIS ANALYZED ACROSS WESTERN/CENTRAL UPPER MICHIGAN
ALONG NE FRINGE OF DEEPER MOISTURE GRADIENT...WHERE RUC ANALYSIS
REVEALS A STRONG LOW-MID LEVEL DEFORMATION AXIS STRETCHING FROM
NRN LAKE MICHIGAN UP THROUGH CENTRAL UPPER MICHIGAN. THIS IN TURN
HAS/IS GENERATING A BAND OF SHOWERS UP THROUGH THAT AREA. ONE
POCKET OF RAIN IN PARTICULAR HAS SEEMINGLY LATCHED ON TO THE
TERRAIN INCREASE OFF LAKE MICHIGAN AND HAS BROUGHT SOME LOCALLY
HEAVY RAIN THROUGH THAT AREA.

NOTHING LIKE THAT HAPPENING HERE. BUT...BATCH OF VERY STUBBORN
STRATUS CONTINUES TO FLOW OFF LAKE HURON WITHIN EASTERLY
FLOW...BRINGING CLOUDY SKIES TO PARTS OF EASTERN UPPER AND NE
LOWER MICHIGAN. STRATUS IS BEGINNING TO ERODE...BUT PROCESS IS
TAKING IT/S TIME.

REST OF TODAY...STRATUS IN THE EAST AND IN EASTERN UPPER MICHIGAN
WILL EVENTUALLY ERODE/MIX OUT...BUT IT WILL TAKE SEVERAL MORE
HOURS AS EAST FLOW CONTINUES TO PUMP COOL/MOIST MARINE AIR INTO
THOSE AREAS. HAVE STRETCHED CLOUDY SKIES OUT FOR SEVERAL MORE
HOURS. ELSEWHERE...HEATING INDUCED CLOUD COVER SHOULD DEVELOP OVER
NW LOWER MICHIGAN AND WE MAY SEE SOME OF THAT AFOREMENTIONED
DEFORMATION CLOUD COVER EXPAND DOWN INTO NW LOWER MICHIGAN AS
WELL. SO... EITHER CLOUDY BECOMING PARTLY SUNNY...OR SUNNY
BECOMING PARTLY SUNNY WILL BE THE NAME OF THE GAME THIS AFTERNOON.
TEMPS WILL OF COURSE BE TRICKY GIVEN THE CLOUDS...AND AREAS EAST
OF I-75 WILL END UP WITH THE LOWER READINGS AND HAVE TWEAKED MAX
TEMPS ACCORDINGLY. BUT...IT WILL NOT TAKE MUCH FOR TEMPS TO
REBOUND WHEN THE SUN FINALLY DOES BREAK OUT. JUST HOPE WE DON/T
GET SOME SORT OF DIFFERENTIAL HEATING BOUNDARY ACROSS NRN
LOWER/EASTERN UPPER MICHIGAN THAT POPS OFF CONVECTION THIS
AFTERNOON. THINK WE ARE TOO CAPPED FOR THAT...BUT WILL SEE.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 246 AM EDT SAT AUG 23 2014

HIGH IMPACT WEATHER POTENTIAL: MINIMAL

PRIMARY FORECAST CHALLENGES: DO SHOWERS MOVE INTO NORTHERN MICHIGAN?

CURRENTLY, AS WAS MENTIONED AT THE EARLIER UPDATE, RAIN SHOWERS
UPSTREAM OF THE FORECAST AREA ARE JUST SOUTH OF MQT AND SAW AND
ALONG THE 700 MB DEWPOINT DEPRESSION GRADIENT, AND IN THE LFQ OF THE
500 MB 30 KNOT JET STREAK MOVING THROUGH N WISCONSIN. MAIN FORCING
THAT IS GOING ON OVERNIGHT IS OVER FARTHER SOUTH AND WEST IN
NEBRASKA WHERE THE DEEPER SFC LOW AND 500 MB VORT AND SPEED MAXES
ARE DIGGING. THIS HAS GIVEN RISE TO THE COMPLEX OF STORMS IN THE
CENTRAL PLAINS. THE SFC LOW IN THE E COLORADO IS LINKED BY A SLOWLY
STRENGTHENING FRONT THAT STRETCHES TO THE NE THROUGH N MINNESOTA AND
UP INTO JAMES BAY TO A WEAKER SFC LOW.

TODAY...THE MODELS ARE IN GOOD AGREEMENT WITH THE
RUC/NAM12/GFS/ECMWF/LOCAL WRF4KM SHOWING THE MORNING ISOLATED
SHOWERS THAT WILL TRY TO PUSH INTO NW LOWER THIS MORNING. HOWEVER,
AS THE 500 MB RIDGE OVER THE UPPER GREAT LAKES CONTINUES TO AMPLIFY,
THE FORCING FOR THE SHOWERS WILL GET PUSHED TO THE NORTH AND WEST
THROUGH THE AFTERNOON. THE FRONT WILL ALSO MOVE TO THE NORTH AND
WEST AS THE SFC LOW IN E COLORADO MOVES OUT OVER THE CENTRAL PLAINS
AND DEEPENS. THIS WILL HELP TO FOCUS MOST OF THE RAIN INSTABILITY
AND THE DYNAMIC SUPPORT OVER THE NORTHERN PLAINS AS DEPICTED BY SPC.

TONIGHT...THIS MOVEMENT OF THE SFC LOW OUT OF THE CENTRAL PLAINS
WILL PUSH INTO NORTH DAKOTA OVERNIGHT CONTINUING TO PULL THE FOCUS
AWAY FROM THE UPPER GREAT LAKES. THIS SHOULD CONTINUE OUR RAIN FREE
STREAK (OR AT LEAST OUR MEASURABLE PRECIPITATION) THROUGH THE NIGHT.
WHILE THERE IS SOME INSTABILITY, THE LACK OF A FOCUS AND THE CAPPING
EXPECTED IN THE EVENING (BLAYER CIN 20-40 J/KG) SHOULD INHIBIT ANY
SHOWERS FROM GETTING GOING. IT DOESN`T LOOK LIKE THERE IS MUCH IN
THE WAY OF ELEVATED INSTABILITY AS THE SHOWALTER INDEX OVER N
MICHIGAN AT ITS LOWEST IS ONLY +2C.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 246 AM EDT SAT AUG 23 2014

A HIGHLY AMPLIFIED 500MB RIDGE WILL BE OVERHEAD TO START OUR SUNDAY.
AN EJECTING UPPER LOW FROM THE NORTHERN HIGH PLAINS WILL HAVE TO
CREST THIS RIDGE...AND WILL PASS WELL TO OUR NORTH MONDAY NIGHT.
THIS WILL FLATTEN OUT THE RIDGE...THOUGH IN OUR NECK OF THE WOODS
500MB HEIGHTS WILL HARDLY LOWER AT ALL. STILL...AN ASSOCIATED COLD
FRONT WILL SLOWLY GET DRAGGED INTO THE AREA MONDAY NIGHT. UNTIL THAT
HAPPENS...IT WILL BE SOMETHING OF A CHALLENGE TO GET A PRECIP THREAT
GOING IN THESE PARTS. BUT IT WON/T BE CHALLENGING TO BECOME
INCREASINGLY WARM AND HUMID.

SUNDAY...CORE OF THE 500MB RIDGE STARTS TO SLIDE DOWNSTREAM IN THE
AFTERNOON. THAT CORRESPONDS WITH A SLIGHT UPTICK IN 1000-850MB
RETURN FLOW. HOWEVER...A SHORTWAVE RIDGE ASCENDING INTO THE LARGER
RIDGE WILL HELP KEEP HEIGHTS HIGH. AT THE SAME TIME...SURFACE HIGH
PRESSURE TO OUR EAST WILL STILL EXTEND A TOUCH OF RIDGING INTO
NORTHERN MI. FROM A CONCEPTUAL MODEL STANDPOINT...IT WILL BE
DIFFICULT TO FIRE OFF CONVECTION IN THIS PATTERN UNTIL HEIGHTS ALOFT
FALL. INDEED...THE MODELS ARE NOT INCLINED TO PROG MUCH IF ANY CAPE.
00Z NAM HAS A LATE-DAY AXIS OF A FEW HUNDRED J/KG OF MUCAPE...
HUGGING THE LAKE MI COAST FROM LTL TRAV BAY SOUTH. THIS IS WHERE
LAKE BREEZE CONVERGENCE AND MOISTURE POOLING WILL BE CONCENTRATED...
THANKS TO A BACKGROUND LIGHT SE SYNOPTIC SURFACE WIND. EVEN SO...AN
82/65 PARCEL HAS ABOUT 50J/KG OF CIN TO OVERCOME...THANKS TO 700MB
TEMPS AROUND 9C.

SO WILL MAINTAIN A DRY FORECAST. CAN GENERALLY EXPECT PARTLY SUNNY
SKIES...WILL SOME BUBBLY CU AND MID/HIGH DEBRIS CLOUDS (INSTABILITY
WILL BE MUCH HIGHER W OF LAKE MI). MAX TEMPS UPPER 70S (EASTERN
UPPER...AND NE LOWER COAST)...TO LOW/MID 80S (INTERIOR SW SECTIONS).

SUN NIGHT/MONDAY...SUB-850MB FLOW MAINTAIN AN EASTERLY COMPONENT
INTO THE EVENING...BEFORE VEERING S TO EVEN SSW OVERNIGHT. THAT WILL
ALLOW A JUICIER AND POTENTIALLY UNSTABLE AIRMASS TO FINALLY MAKE
INROADS. HOWEVER...THAT WILL BE SLOW AT 1ST...WITH PERHAPS WESTERN
CHIP/MACK THE ONLY PLACE PROGGED TO SEE SOME CAPE ARRIVE BY MORNING.
THIS COULD ALLOW CONVECTION ORIGINATING IN WI A CHANCE TO GRAZE BY
THAT AREA OVERNIGHT. BUT...GIVEN THE MODELS TEND TO BE TOO QUICK TO
BREAK DOWN RIDGING AND CIN...WILL MAINTAIN A DRY FORECAST FOR SUN
NIGHT.

DEEP MOISTURE/MODERATE INSTABILITY PLUME WILL VERY SLOWLY WORK IN
FROM THE WNW MONDAY...AHEAD OF A COLD FRONT ADVANCING ACROSS WI.
HEIGHTS/TEMPS ALOFT HERE REMAIN HIGH...BUT ACTIVITY SHOULD DEVELOP
UPSTREAM IN WI AND MOVE E AND NE TOWARD WESTERN/NORTHERN
SECTIONS...ESPECIALLY LATER IN THE DAY. WILL MAINTAIN CHANCE POPS BY
AFTERNOON IN THE NW 2/3DS OF THE FORECAST AREA...INCLUDING HIGH
CHANCE (50) POPS IN WESTERN CHIP/MACK.

MIN TEMPS NEAR 60F TO THE MID 60S. MAX TEMPS NEAR 80 TO THE MID
80S...A FEW UPPER 80S POSSIBLE IN THE INTERIOR OF NORTHERN LOWER.
DEW POINTS WILL BE RISING INTO THE MID AND UPPER 60S...SO IT WILL
ALSO BE QUITE STICKY ON MONDAY.

REST OF THE FORECAST...SHAPING UP FOR A FAVORABLE MCS PATTERN
MID-WEEK. A STALLED FRONTAL ZONE (AND A WARM/HUMID AIRMASS) WILL BE
JUST TO OUR SOUTH...WITH FAST ZONAL FLOW IN THE NORTHERN LAKES.
CONSALL GRIDS ARE TRYING TO NUDGE US TOWARD LIKELY POPS IN SOME
PERIODS. AM BACKING AWAY FROM THIS THINKING GIVEN THAT IT/S
CONVECTION WE/RE TALKING ABOUT...AND PRECIP HAS UNDERPERFORMED OVER
THE LAST WEEK OR SO. TEMPS WILL BE DRIFTING BACK TOWARD OR A BIT
UNDER CLIMO BY LATE IN THE WORK WEEK...THOUGH PROBABLY NOT AS COOL
AS THE GFS/MEX GUIDANCE ADVERTISES...AS THE ECMWF IS SLOWER AND LESS
AMPLIFIED WITH THE UPPER TROF THAT PROGRESSES INTO THE PLAINS STATES
MID/LATE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 132 PM EDT SAT AUG 23 2014

STUBBORN STRATUS DECK FLOWING OFF LAKE HURON ON EASTERLY WINDS
CONTINUES TO BRING MVFR FLIGHT CONDITIONS TO PLN/APN...ALTHOUGH
STRATUS DECK HAS/IS SLOWLY ERODING. CLOUDS SHOULD SCATTER OUT BY
MID TO LATE AFTERNOON AT THOSE SITES LEAVING A PERIOD OF VFR
CONDITIONS HEADING INTO THE EVENING. VFR CONDITIONS AT TVC AND MBL
WILL PERSIST.

TONIGHT...FEAR CYCLE WILL REPEAT AS MARINE STRATUS ONCE AGAIN
REDEVELOPS OFF THE LAKE INTO NE LOWER MICHIGAN...LATER THIS
EVENING AND FOR THE OVERNIGHT HOURS WITHIN PERSISTENT E/SE FLOW.
THUS...HAVE IFR CIGS AND LOW VSBYS ONCE AGAIN TAKING OFF AT
APN/PLN THROUGH THE COURSE OF THE NIGHT WHILE TVC/MBL REMAIN
LARGELY VFR WITH SOME MINOR REDUCTIONS TO VSBY DUE TO LIGHT FOG.

WINDS...LIGHT EASTERLY TODAY...CALM TONIGHT AND LIGHT SE ON
SUNDAY.

&&

.MARINE...
ISSUED AT 246 AM EDT SAT AUG 23 2014

OVER THE NEXT 48 HOURS, THE WINDS WILL SLOWLY INCREASE AND VEER
FROM THE EAST TO THE SOUTH LOW PRESSURE NEAR COLORADO DEEPENS AND
MOVES INTO NORTH DAKOTA. SO TODAY THROUGH SUNDAY NIGHT, WILL
EXPECT THAT WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT
CONDITIONS.


&&

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

&&

$$

UPDATE...ADAM
SYNOPSIS...JZ
SHORT TERM...JL
LONG TERM...JZ
AVIATION...ADAM
MARINE...JL






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