Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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000
FXUS63 KMKX 150553 AAB
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1153 PM CST SUN DEC 14 2014

.UPDATE...

VISIBILITIES ARE IMPROVING A LITTLE OVER SOUTHEAST WI PER SURFACE
OBS BUT THERE IS STILL PLENTY OF DENSE FOG SHOWING UP IN THE
WEBCAMS. THERE ARE SOME HIGH CLOUDS DRIFTING OVERHEAD AS LOW
PRESSURE APPROACHES. LAKESHORE COUNTIES ARE ALSO SHOWING MORE SIGNS
OF FOG ON THE WEB CAMS. I HANDLED THE LAKESHORE COUNTIES WITH AN SPS
FOR PATCHY DENSE FOG AND THERE IS A DENSE FOG ADVISORY IN EFFECT
ELSEWHERE.

&&

.AVIATION/06Z TAFS/...

REDUCED VISIBILITIES AND LOW CLOUDS LINGERING ACROSS THE FORECAST
AREA THROUGH TONIGHT. THE DENSE FOG IS SOMEWHAT TRANSIENT AND RECENT
OBS HAVE SHOWN SLIGHT IMPROVEMENT AS HIGH CLOUDS DRIFT INTO THE
REGION.

THERE WILL BE GRADUAL IMPROVEMENT OF VSBY AND CIGS AGAIN MONDAY...
THOUGH CONDITIONS WILL LIKELY REMAIN IN THE IFR TO LOW MVFR RANGE.


&&

.PREV DISCUSSION... /ISSUED 759 PM CST SUN DEC 14 2014/

UPDATE...

WE EXPANDED THE DENSE FOG ADVISORY EASTWARD EARLY THIS EVENING AND
IT NOW COVERS ALL OF THE MKX AREA EXCEPT THE LAKESHORE COUNTIES.
WEBCAMS ARE SHOWING DECREASING VISIBILITIES WITH TIME THIS
EVENING... SO IT IS STILL POSSIBLE WE WILL HAVE TO EXPAND THE DENSE
FOG ADVISORY ALL THE WAY TO THE LAKE. FOR NOW... SURFACE OBSERVATION
SITES ARE REMAINING WELL ABOVE ONE QUARTER MILE VSBY.

AVIATION/00Z TAFS/...

REDUCED VISIBILITIES AND LOW CLOUDS LINGERING ACROSS THE FORECAST
AREA THROUGH TONIGHT. DENSE FOG RETURNED TO MSN AND IS IN AND OUT AT
UES. EXPECT DENSE FOG MAINLY WEST OF A LINE FROM FOND DU LAC TO
WAUKESHA TO BURLINGTON.

MAY SEE SOME DRIZZLE AT TIMES THROUGH TONIGHT...WITH LIGHT RAIN
EXPECTED MONDAY.

WILL SEE GRADUAL IMPROVEMENT OF VSBY AND CIGS AGAIN MONDAY... THOUGH
CONDITIONS WILL LIKELY REMAIN IN THE IFR TO LOW MVFR RANGE.

PREV DISCUSSION... /ISSUED 202 PM CST SUN DEC 14 2014/

SHORT TERM...

NOT MUCH WILL CHANGE INTO TONIGHT. WARM TEMPS ALOFT WILL REMAIN IN
PLACE...WITH A STRONG LOW LEVEL INVERSION PERSISTING. VISIBILITIES
HAVE IMPROVED AGAIN DURING THE DAYTIME HOURS...BUT MANY LOCATIONS
ARE STILL 2 OR LESS MILES. THINK THE BEST CHANCE FOR MORE DENSE FOG
TONIGHT WILL BE IN THE WESTERN FORECAST AREA. THIS IS BASED ON
CURRENT OBS AND THE FACT THAT VISIBILITIES WENT DOWN QUICKER AND FOR
A LONGER PERIOD IN THE WEST LAST NIGHT. HAVE DECIDED TO PUT A DENSE
FOG ADVISORY OUT FOR WESTERN AREAS UNTIL NOON TOMORROW. THE ADVISORY
WILL START THIS AFTERNOON IN THE SOUTHWEST WHERE THERE ARE STILL
REPORTS OF DENSE FOG...AND AT 6 PM ELSEWHERE IN THE WESTERN FORECAST
AREA.

PRECIPITABLE WATER VALUES WILL INCREASE TO 8 OR 9 TENTHS OF AN INCH
MONDAY AS LOW PRESSURE APPROACHES. WITH DEEPER SATURATION AND SOME
LIFT FINALLY SHOWING UP IN SOUNDINGS...SEEMS LIKE A PRETTY GOOD BET
FOR SOME LIGHT RAIN AS AN AREA OF WARM ADVECTION LIFTS THROUGH.

GIVEN THE CLOUDS AND CURRENT DEWPOINTS...TEMPS WILL LIKELY ONLY FALL
TO THE LOW OR MID 40S TONIGHT. DEPENDING ON HOW FAR THE TEMPS FALL
BY MIDNIGHT MONDAY NIGHT...MAY SEE THE HIGHEST LOW TEMPS ON RECORD
FOR DEC 15.  TEMPS DURING THE DAY WILL BE MILD...BUT LIKELY FALL A
COUPLE DEGREES SHY OF RECORD HIGHS.

MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE...HIGH

THE 250 MB AND 500 MB SHORTWAVE MOVES ACROSS SOUTHERN WISCONSIN
AND NORTHERN ILLINOIS MONDAY NIGHT AND REACHES THE EASTERN GREAT
LAKES BY TUESDAY. A SECOND SHORTWAVE WILL BE DROPPING DOWN FROM
THE NORTHWEST TO NORTHEAST MINNESOTA AND THE WESTERN LAKE
SUPERIOR AREA TUESDAY. WEAK 700 MB UPWARD MOTION CONTINUES MONDAY
NIGHT AND BECOMES DOWNWARD ON TUESDAY. 700 RH VALUES ARE HIGH
MONDAY NIGHT...THEN BECOME DRY BY TUESDAY AFTERNOON. THE 850 MB
LEVEL DRIES FROM THE WEST DURING THE AFTERNOON...WHILE 925
REMAINS HIGH...ESPECIALLY NORTH SECTIONS. EVEN IN THE SOUTHWEST
NAM SOUNDINGS HAVE A SHALLOW SATURATED LAYER CONTINUING BELOW A
WEAK INVERSION. AS A RESULT MUCH OF THE FORECAST AREA SHOULD
REMAIN IN STRATUS.

THE SURFACE LOW MOVES ACROSS NORTHERN ILLINOIS AND FAR SOUTHEAST
WISCONSIN MONDAY NIGHT AND MOVES TO THE SOUTHERN LAKE HURON AND
LAKE ERIE AREA TUESDAY. NAM SOUNDINGS CONTINUE TO SHOW
PRECIPITATION SHOULD BE DIMINISHING AS BOUNDARY LAYER TEMPERATURES
COOL ENOUGH FOR SNOW...WITH A NARROW WARM AREA AROUND 875 MB
STAYING ABOVE FREEZING...EVEN AS THICKNESS VALUES COOL ENOUGH FOR
SNOW.

TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE...MEDIUM

THE SECOND SHORTWAVE REMAINS ACROSS THE NORTHERN WISCONSIN TO
LAKE HURON AREA. THE ECMWF HAS NOW TRENDED TO THE NAM/GFS. 700 MB
REMAINS MAINLY DRY...ALTHOUGH SOME INCREASE IN RH OCCURS TOWARDS
CENTRAL WISCONSIN. THE 850 MB LEVEL IS RATHER DRY...WHILE 925
REMAINS HIGH...ESPECIALLY NORTH SECTIONS WHERE THE STRATUS WILL
LIKELY CONTINUE.

THE SURFACE LOW MOVES OFF INTO SOUTHEAST CANADA WITH A RATHER
BRISK NORTH FLOW ACROSS SOUTHEAST WISCONSIN WITH COLD AIR
ADVECTION. MEANWHILE A SURFACE HIGH CENTERED OVER THE NORTHERN
PLAINS BUILDS TOWARDS THE UPPER MISSISSIPPI VALLEY WEDNESDAY.

LONG TERM...

WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE...MEDIUM

THE MID LEVEL TROUGH EXTENDING ACROSS THE GREAT LAKES AT 500 MB
GRADUALLY WEAKENS.

THE SURFACE HIGH MOVES INTO WISCONSIN WITH SEASONABLE
TEMPERATURES EXPECTED.

THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM

THE FLOW BECOMES WEAK ACROSS THE UPPER MIDWEST AT 500 MB WITH A
WEAK RIDGE TRYING TO DEVELOP.

SURFACE HIGH PRESSURE IS EXPECTED TO EXTEND ACROSS THE UPPER
MIDWEST AND WESTERN GREAT LAKES.

FRIDAY NIGHT AND AND SATURDAY...FORECAST CONFIDENCE...MEDIUM

A SPLIT FLOW PATTERN EXISTS WITH ONE SHORTWAVE IN THE SOUTHERN
STREAM. THE GFS/DGEX AND ECMWF ALL DIFFER ON THE LOCATION AND
STRENGTH OF THIS SHORTWAVE. THE GFS IS MORE NORTH INTO THE MID
MISSISSIPPI VALLEY...WITH THE ECMWF MORE TOWARDS THE LOWER
MISSISSIPPI VALLEY. THE DGEX HAS A FLATTER SHORTWAVE.

THE NORTHERN STREAM JET IS WELL NORTH INTO CANADA.

SURFACE HIGH PRESSURE IS EXPECTED TO EXTEND ACROSS THE UPPER
GREAT LAKES. THE PRECIPITATION WITH A SURFACE LOW OVER THE
SOUTHEAST U.S. IS TO THE SOUTH OF WISCONSIN ON THE 00Z ECMWF...BUT
DOES REACH FAR SOUTHERN WISCONSIN ON THE 12Z GFS WITH LESS THAN A
TENTH OF AN INCH. THICKNESS VALUES INDICATE THIS WOULD BE SNOW IF
IT OCCURRED.

SUNDAY...FORECAST CONFIDENCE...MEDIUM

THE SHORTWAVE MOVES OFF TO THE EAST WITH A LINGERING TROUGH INTO
THE GREAT LAKES...AS ANOTHER TROUGH DIGS OVER THE SOUTHWEST U.S.

THE SURFACE LOW MOVES OFF TO THE EASTERN U.S. WITH HIGH PRESSURE
BUILDING INTO THE PLAINS AND MISSISSIPPI RIVER VALLEY.

AVIATION/00Z TAFS/...

REDUCED VISIBILITIES AND LOW CLOUDS LINGERING ACROSS THE FORECAST
AREA THIS AFTERNOON. WOULD NOT BE SURPRISED AT SOME MORE DENSE FOG
TONIGHT...PARTICULARLY WEST OF A LINE FROM FOND DU LAC TO
JANESVILLE.

MAY SEE SOME DRIZZLE AT TIMES THROUGH TONIGHT...WITH LIGHT RAIN
EXPECTED MONDAY.

WILL SEE GRADUAL IMPROVEMENT OF VSBY AND CIGS AGAIN
TOMORROW...THOUGH CONDITIONS WILL LIKELY REMAIN IN THE IFR TO LOW
MVFR RANGE.

MARINE...

COULD SEE SOME MORE FOG TONIGHT INTO MONDAY...BUT VISIBILITIES
SHOULD GENERALLY STAY ABOVE 1 MILE.

SOUTH TO SOUTHEAST WINDS WILL GUST TO AROUND 20 KNOTS MONDAY...WITH
WAVES BUILDING TO 2 TO 4 FEET. WINDS AND WAVES LOOK TO STAY JUST
UNDER SMALL CRAFT ADVISORY LEVELS THOUGH.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL NOON CST MONDAY FOR WIZ046-047-051-
     056>059-062>065-067>070.

LM...NONE.
&&

$$

UPDATE...MRC
TONIGHT/MONDAY AND AVIATION/MARINE...DDV
MONDAY NIGHT THROUGH SUNDAY...HENTZ



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