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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1159 AM EDT THU OCT 23 2014

.SYNOPSIS...
ISSUED AT 347 AM EDT THU OCT 23 2014

HIGH PRESSURE WILL START TO EXIT EAST TODAY. THIS WILL ALLOW A 
WEAK DISTURBANCE WITH A PERIOD OF LIGHT RAIN AND DRIZZLE TO CROSS
THE REGION TONIGHT INTO TOMORROW MORNING. A COLD FRONT WILL THEN
CROSS NORTHERN MICHIGAN SATURDAY...BRINGING SOME GUSTY WINDS AND
COOLER TEMPERATURES. 

THE NEXT LOW PRESSURE SYSTEM WILL ARRIVE IN THE EARLY TO MIDDLE
PARTS OF NEXT WORK WEEK...RESULTING IN ADDITIONAL CHANCES FOR
RAIN.

&&

.UPDATE...
ISSUED AT 1135 AM EDT THU OCT 23 2014

VERY TRICKY CLOUD FORECAST ONCE AGAIN TODAY. LARGE AREA OF STRATUS
ACROSS NORTH CENTRAL LOWER HAS MOVED INTO SOUTHEAST ZONES OF THE
FORECAST AREA. THE EXTENT AND MOVEMENT OF THIS AREA OF CLOUDS IS
RATHER TOUGH AS THERE IS VERY LITTLE STEERING FLOW AS IT IS
TRAPPED BELOW SURFACE HIGH PRESSURE. GENERAL TREND IS FOR
CONTINUED SLOW EROSION THROUGH EARLY AFTERNOON...THOUGH HAD TO
INCREASE CLOUD COVER TO START. DID KNOCK A COUPLE OF DEGREES OFF OF
HIGH TEMPERATURES DUE TO THE LIGHT FLOW AND ONLY SHALLOW MIXING
EXPECTED.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 347 AM EDT THU OCT 23 2014

...A CHILLY START FOR SURE...

IMPACTS: REDUCED VISIBILITY EARLY THIS MORNING. LOCALIZED DENSE FOG.

CURRENT WEATHER AND SYNOPTIC PATTERN:

UPPER LEVEL RIDGE CURRENTLY OVERHEAD IS SHALLOWING OUT AS AN 
UPSTREAM FAIRLY SHARP TROUGH IS MAKING WAY TOWARD THE FAR WESTERN 
GREAT LAKES. AN ASSOCIATED COLD/OCCLUDED FRONT WAS SEEN ACROSS 
MN/IA/KS/NE WITH A CORRIDOR OF MOISTURE AND WEAK-MODEST -DIVQ WHICH 
WAS PRODUCING SOME LIGHT RAIN AND SPRINKLES. NOT MUCH LIQUID IN 
THESE SHOWERS...AS THE DEEPER MOISTURE IS WORKING INTO WHAT WAS A 
VERY DRY AIR MASS. LATEST SATELLITE AND SHORT TERM DATA SUGGEST/SHOW 
POTENTIALLY TWO SEPARATE VORTICITY MAXIMA WITHIN THIS TROUGH...EACH 
SHOWING A CONGEALED AREA OF SHOWERS. THESE TWO WAVES ARE LIKELY 
WORKING IN OPPOSITE DIRECTIONS...ONE EAST AND ANOTHER TO THE 
NORTH...PER SFC DEWPOINT ANALYSIS SHOWING THE MOISTURE SHEARING OUT 
WITH TIME.

OVER NRN MICHIGAN...THE DEEPEST OF DRY AIR IS OVERHEAD...ALONG WITH 
THE UPPER AND SFC RIDGES. STRONG RADIATIONAL COOLING HAS LED TO SOME 
SHALLOW FOG AND STRATUS DEVELOPMENT. THIS WAS MAINLY ONGOING ACROSS 
NE LOWER...WHERE YESTERDAYS VISIBLE SATELLITE SHOWED A LINGERING 
STRATUS DECK...SURPRISINGLY WELL INTO THE DAY YESTERDAY. THIS KEPT 
SFC/LOW LEVEL MOISTURE FROM MIXING OUT...AND HENCE THE STRATUS/FOG. 
SOME VISIBILITIES WERE DOWN TO A QUARTER OF A MILE IN SPOTS. TEMPS 
WERE AS COLD AS THE LOWER 20S IN THE LOWEST LYING AREAS.

SYNOPTIC PATTERN/WEATHER EVOLUTION:

NOTHING TO CRAZY IN OUR WEATHER OVER THE NEXT 24 HRS...BUT WE WILL 
HAVE THE AFOREMENTIONED UPPER TROUGH HEADING INTO THE REGION. THE 
TWO SUGGESTED SEPARATE VORTICITY MAXIMA WILL CONTINUE TO TAKE ON 
DIFFERENT TRACKS. ONE...LIFTING ENE INTO ONTARIO...AND THE OTHER 
INTO SRN LAKE MICHIGAN. THIS WILL CONTINUE TO SHEAR OUT THE MOISTURE 
AND FORCING...WHILE PUSHING INTO OUR VERY DRY AIR MASS. THEREFORE 
NOT EXPECTING ANY SORT OF COVERAGE AS WE SEE CURRENTLY UPSTREAM. 
FORCING AND FCST BFR SOUNDINGS HOWEVER DO SUGGEST THAT SOME LIGHT 
RAIN OR SPRINKLES COULD MOVE IN TOWARD EVENING IN NW LOWER AND 
EASTERN UPPER...AND THEN POSSIBLY INTO THE I75 CORRIDOR THROUGH 
MIDNIGHT OR SO. BEHIND THAT...AND VERIFIED BY UPSTREAM SFC OBS...A 
PERIOD OF DEEP LOW LEVEL MOISTURE WILL ARRIVE. THIS WILL LEAVE SKIES 
CLOUDY IN THE LOW LEVELS...WITH A PERIOD OF DRIZZLE LIKELY...WHICH 
WILL LAST FOR A BIT INTO FRIDAY MORNING.

SKIES WILL INCREASE IN CLOUDINESS THIS AFTERNOON...AND ESPECIALLY 
THROUGH THE NIGHT TO ALL CLOUDY. PRIOR TO THE CLOUDS ACROSS NE LOWER 
THIS EVENING...TEMPERATURES WILL DROP VERY QUICKLY WITH PATCHY FOG 
DEVELOPMENT LIKELY. THESE TEMPS HERE WILL CLIMB AFTER THAT.

HIGH TEMPS TODAY WILL BE IN THE LOWER TO MIDDLE 50S...WITH LOWS 
TONIGHT RANGING FROM THE UPPER 20S LOWER LOWER 30S IN NE LOWER...TO 
THE UPPER 30S AND AROUND 40F WEST OF I-75 (WHERE CLOUDS WILL ALREADY 
BE BY THIS EVENING).  

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 347 AM EDT THU OCT 23 2014

...WET WEATHER FOR MONDAY THROUGH WEDNESDAY...

HIGH IMPACT WEATHER POTENTIAL: NONE. 

PRIMARY FORECAST CHALLENGES: HOW DOES THIS SYSTEM NEXT WEEK EVOLVE? 

OVERVIEW...THE PROCESS OF FLATTENING THE CURRENTLY AMPLIFIED PATTERN 
CONTINUES WITH THE 500 MB LOW OVER THE EAST COAST, NOW CUTTING OFF 
FROM THE 500 MB FLOW. THIS IS WHAT LEADS TO THE SPLIT FLOW OVER THE 
UPPER GREAT LAKES BY FRIDAY MORNING. 

(10/24)FRIDAY...THE MODELS ARE IN GOOD AGREEMENT WITH THE 500 MB 
FLOW SPLIT, WITH THE 850 MB AND LOWER MOISTURE STALLING AS IT MOVES 
ACROSS THE FORECAST AREA. THE MODEL SOUNDINGS SHOW MOISTURE 
INCREASING WITH HEIGHT UNDER THE INVERSION SO THAT THERE IS STRONG 
CHANCE THAT WE'LL HAVE PATCH DRIZZLE AT 12Z. IT LOOKS LIKE BY 
SOUNDINGS THAT THE MOISTURE SHOULD MIX OUT. SO KEPT THE DRIZZLE IN 
THROUGH 15Z, AND THEN WITH THE THINNING MOISTURE, STOP THE DRIZZLE 
AS THE CLOUDS BEGIN TO LIFT UP WITH THE MIXING IN THE LOWER 
ATMOSPHERE. 

FRIDAY NIGHT...AS A 500 MB SHORTWAVE TROUGH MOVE THROUGH THE UPPER 
GREAT LAKES THE MOISTURE IN THE 700-500 MB LAYER STAYS NORTH OF THE 
STRAITS, THIS LEAVES MOISTURE ALONG THE SFC FRONT AT 850 MB AND 
BELOW A LITTLE THIN. IT LOOKS AS THOUGH OVERNIGHT THERE MAY BE SOME 
ADDED MOISTURE AS THE SYSTEM MOVES TO THE SOUTHEAST OVER NE LOWER. 
HOWEVER, IT LOOKS LIKE THE CHANCE FOR RAIN IS PRETTY SMALL. 
CONTEMPLATED TAKING THE RAIN OUT OF THE FORECAST THERE, BUT WILL 
LEAVE IN THE SMALL CHANCE WE HAVE FOR NOW. 

(10/25)SATURDAY...500 MB HEIGHTS BEGIN BUILD INTO THE UPPER GREAT 
LAKES. 850 MB TEMPERATURES BEGIN TO FALL OFF AS THE COLD FRONT MOVES 
THROUGH. WILL HAVE TO WATCH FOR LE RAIN BY THE EARLY EVENING AS THE 
850 MB TEMPERATURES GET TO AROUND 0C TO -2C IF THE GFS IS RIGHT. 
THEN TEMPERATURES WARM BETWEEN 06Z AND 12Z AS THE SFC HIGH BEGINS TO 
BUILD INTO THE UPPER GREAT LAKES. FOR NOW WILL LEAVE THE DRY 
WEATHER, BUT THIS COULD CHANGE INTO A CHILLY DAMP NIGHT IN NW LOWER 
IF THE MODELS TREND MORE THIS WAY. 

EXTENDED (SUNDAY THROUGH WEDNESDAY)...(10/26)SUNDAY...MODELS ARE IN 
BETTER AGREEMENT AND KEEP THE PERIOD DRY AS THE SFC HIGH FORCES THE 
MOISTURE EAST AGAIN AND ALLOWING THE 850 MB AND SFC TEMPERATURES TO 
RISE. (10/27)MONDAY...THERE ARE SOME MINOR TIMING ISSUES WITH THE 
ONSET OF TH RAIN WITH THE GFS A LITTLE FASTER, AND A FLATTER RIDGE 
AT 500 MB. THE ECWMF IS A LITTLE MORE AMPLIFIED, SO THINK THAT IT 
MAY BE ONTO THE RIGHT TRACK WITH THE SLOWER ONSET OF RAIN. 
(10/28)TUESDAY...THE RAIN CONTINUES THROUGH THE DAY NOW, BUT THE GFS 
STILL WRAPS THE SFC LOW PRETTY TIGHT. AM BEGINNING TO WONDER IF THE 
THERE IS SOME CONVECTIVE FEEDBACK ISSUES WITH THE GFS WITH ALL OF 
THE PRECIPITATION IT FORMS, AND THE MUCH DEEPER LOW. THIS WOULD 
ACCOUNT FOR THE DIFFERENCES BETWEEN THE TWO MODELS. 
(10/29)WEDNESDAY...AGAIN BOTH MODELS HAVE RAIN FOR DIFFERENT 
REASONS. WILL CONTINUE THE CHANCES OF RAIN AND NOT SIDE WITH HOW WE 
GET TO THIS POINT UNTIL THERE ARE FEW MORE RUNS IN. 

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 646 AM EDT THU OCT 23 2014

...SHALLOW GROUND FOG AND STRATUS ROAMING THE AREA...

SFC RIDGE AND VERY DRY AIR OVERHEAD HAS LED TO STRONG RADIATIONAL 
COOLING OVERNIGHT. THIS HAS RESULTED IN SHALLOW SFC GROUND FOG AND 
STRATUS FOR MUCH OF NE LOWER...WHICH IS GONE FROM APN...BUT STILL
IN THE AREA. COULD STILL SEE A BRIEF PERIOD OF POOR VISIBILITY AND
SHALLOW STRATUS...BUT CONFIDENCE IS LOW FOR THAT. UNLIKE
YESTERDAY...ANY FOG AND STRATUS THAT HAPPENS TO BE NEAR/AT THE
AIRPORTS...WILL BURN OFF QUICKLY...LEADING TO VFR CONDITIONS AND
LOTS OF SUN. HIGH LEVEL CLOUDS WILL INCREASE ACROSS NW LOWER LATER
THIS AFTERNOON...AND SPREAD EASTWARD OVERNIGHT. THESE CLOUDS WILL
DEEPEN TO THE LOW LEVELS RESULTING IN A POSSIBLE PERIOD OF LIGHT
RAIN AND SPRINKLES...THEN ULTIMATELY SUB 1KFT CLOUDS WITH PERIODS
OF DRIZZLE AND REDUCED VISIBILITIES AGAIN.

LIGHT WINDS WILL TURN SOUTHERLY AOB 10KTS...THEN VERY LIGHT 
SOUTH/CALM TONIGHT. 


&&

.MARINE...
ISSUED AT 347 AM EDT THU OCT 23 2014

...POSSIBLE ADVISORY LEVEL WINDS BY THE WEEKEND...

SFC HIGH PRESSURE AND VERY DRY AIR OVERHEAD WILL SLOWLY PUSH EAST 
THROUGH TONIGHT...WHILE A DECAYING SFC TROUGH ARRIVES TONIGHT. LIGHT 
WINDS WILL TURN SOUTHERLY OVER THIS TIME...BUT REMAIN WELL BELOW 
ADVISORY LEVELS. A MORE SUBSTANTIAL FRONT ARRIVES FRIDAY NIGHT BRING 
POSSIBLE ADVISORY LEVEL SW WINDS TO LAKE MICHIGAN. COLD AIR POURING 
IN SATURDAY VIA A WIND SHIFT OUT OF THE WNW WILL RESULT IN 
INCREASING OVERLAKE INSTABILITY AND A BETTER CHANCE FOR ADVISORY 
LEVEL WINDS. 


&&

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

&&

$$

UPDATE...AS
SYNOPSIS...SMD
SHORT TERM...SMD
LONG TERM...JL
AVIATION...SMD
MARINE...SMD

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