Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 131959
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
259 PM CDT SUN APR 13 2014

.SHORT TERM...

.TONIGHT AND MONDAY - CONFIDENCE...MEDIUM LOW LEVEL NORTHEAST FLOW
RESULTING IN AREAS OF DENSE FOG COMING OFF THE LAKE. AS WINDS RAMP
UP AND RAIN MOVES IN THINKING THIS WILL DISPERSE SOME. MAIN
SHORTWAVE WILL LIFT NORTHEAST FROM THE CENTRAL PLAINS. A HINT OF
SOME COUPLED JET ACTION WILL AID IN THE VERTICAL MOTION WITH
SURFACE/850 LOWS TRACKING INTO LOWER MICHIGAN BY LATER IN THE NIGHT.
MODELS SHOWING ANOTHER INCH OR TWO OF RAIN SO FLOOD WATCH REMAINS
CWA WIDE. THERMAL PROFILE SHOWS AIRMASS REMAINING WARM ENOUGH FOR
ALL RAIN THROUGH AT LEAST 6Z. AFTER 6Z THINGS GET A BIT TRICKY AS
PROFILE COOLS AS NORTH WINDS ON BACK SIDE OF SURFACE/850 LOWS DRAG
COLDER AIR IN...COLLAPSING THE THERMAL PROFILE A BIT. EXPECT THE
NORTHERN AND NORTHWEST CWA TO SEE A MIX FIRST LATER IN THE NIGHT
WITH THE TRANSITION ZONE SAGGING SOUTHEASTWARD INTO MONDAY MORNING.
THE DELAYED EROSION OF 850 WARM LAYER...LOSS OF ICE CRYSTALS IN THE
DENDRIDIC GROWTH ZONE AND THE WARM GROUND ALL SUGGEST KEEPING
ANTICIPATED SNOW ACCUMS ON THE LIGHT SIDE AND MAINLY ON GRASSY
SURFACES. HOWEVER GIVEN SOME OF THE HIGHER QPF NUMBERS FROM THE NAM
AND GFS IN THE NW CWA AFTER 6Z...COINCIDING WITH THE INFLUX OF COLD
AIR...DECIDED TO BUMP SNOW AMOUNTS JUST A SMIDGE THERE. A FEW
HUNDREDTHS OF QPF LINGERS BEYOND 12Z. MENTIONED A MIX OF RAIN AND
SNOW SHOWERS GIVEN BUFKIT SOUNDINGS SHOWING A LOSS OF SATURATION
WITHIN THE DENDRIDIC GROWTH ZONE FOR A TIME ON MONDAY.

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

THE MAIN MID/UPPER TROUGH AXIS MOVES ACROSS WISCONSIN LATE MONDAY
NIGHT AND TUESDAY MORNING AND REACHES LAKE MICHIGAN AROUND NOON.
THE 250 MB JET MAX INCREASES TO 140 KNOTS BY SUNRISE AS IT LIFTS
NORTHEAST ACROSS LOWER MICHIGAN. UPPER DIVERGENCE EXISTS AHEAD OF
THE TROUGH AXIS AND WEAK CONVERGENCE BEHIND. THE 700 MB TROUGH
AXIS IS FARTHER EAST WITH  WEAK 700 MB UPWARD MOTION OVER THE FAR
SOUTHEAST TIP EARLY MONDAY EVENING...OTHERWISE DOWNWARD MOTION
EXISTS TROUGH THE NIGHT AND TUESDAY MORNING.

RELATIVE HUMIDITY VALUES DRY DURING FAR SOUTHEAST EARLY IN THE
EVENING AND REMAIN DRY OVERNIGHT AND TUESDAY...WITH SOME INCREASE
IN RH TOWARD THE MISSISSIPPI RIVER TOWARD EVENING. 850 MB RH
REMAINS FAIRLY HIGH...SO SOME STRATOCUMULUS SHOULD REMAIN
ESPECIALLY NORTHEAST AREA.

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

THE MID/UPPER LEVEL FLOW BECOMES ZONAL BY WEDNESDAY MORNING. UPPER
DIVERGENCE INCREASES SOMEWHAT WEDNESDAY AFTERNOON. LOW LEVEL
WARM AIR ADVECTION BEGINS TUESDAY NIGHT AND STRENGTHENS
WEDNESDAY. MODERATE 700 MPH UPWARD MOTION BEGINS LATER TUESDAY
NIGHT OVER NORTHWEST AREAS...WITH WEAKER UPWARD MOTION SOUTHEAST.
A NARROW BAND SATURATES AT 700 MB BY MIDNIGHT...THAT LIFTS INTO
CENTRAL WISCONSIN BY NOON WEDNESDAY AS A 50 KNOT 700 MB JET MAX
MOVES ACROSS SOUTH CENTRAL WISCONSIN. AN EVEN STRONGER 850 MB JET
MAX OF 55 KNOTS APPROACHES SOUTH CENTRAL WISCONSIN BY
MIDNIGHT...BEFORE EXTENDING ACROSS SOUTHERN WISCONSIN WEDNESDAY.

MOST OF THE PRECIPITATION STAYS NORTH EARLY WEDNESDAY
MORNING..BUT THE NAM DOES BRING SOME LIGHT PRECIPITATION MAINLY
NORTH OF A DELLS TO SHEBOYGAN LINE. TO COMPLICATE
THINGS...THICKNESS AND 850 MB TEMPERATURES ARE COLD ENOUGH FOR
SNOW. NAM FORECAST SOUNDINGS SHOW DRY AIR BLOW 800 MB...BUT MID
LAPSE RATES ARE RATHER STEEP SO THAT MAY NOT PREVENT PRECIP FROM
REACHINGTHE GROUND IF IT IS MORE CONVECTIVE IN NATURE.

.LONG TERM...

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

THE MID/UPPER LEVEL FLOW BECOMES SOUTHWEST THURSDAY AS A TROUGH
MOVES ACROSS THE PLAINS. THE 12Z GFS IS STRONGER WITH THIS.

THE 00Z ECMWF HAS COME IN LINE WITH THE GFS AND NOW BOTH SHOW A
TROUGH EXTENDING FROM EASTERN OKLAHOMA INTO SOUTHERN WISCONSIN
THURSDAY. PRECIPITATION IS BEHIND THE TROUGH AXIS ON BOTH
MODELS...WITH BOTH MODELS SHOWING VERY LIGHT RAIN FOR THURSDAY.

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

THE 12Z GFS SWINGS A RATHER SHARP SHORTWAVE INTO WISCONSIN FRIDAY
WITH AN UPPER LOW OVER THE MINNESOTA/DAKOTA BORDER. IT TAKES THE
UPPER LOW INTO WISCONSIN FRIDAY NIGHT. THE ECMWF AND DGEX HAVE A
MORE OPEN WAVE WHICH APPEARS MORE REASONABLE.

THE 12Z GFS BRINGS A MODERATE AMOUNT OF PRECIPITATION WITH THE
UPPER LOW FEATURE WITH COLDER THICKNESS VALUES. THE ECMWF BRINGS
A SURFACE HIGH ACROSS WISCONSIN BY SATURDAY MORNING.

.SUNDAY...FORECAST CONFIDENCE...LOW

THE 12Z GFS HAS A LARGE HIGH ACROSS WISCONSIN SUNDAY...WHILE THE
ECMWF HAS WARM AIR ADVECTION AND PRECIPITATION SATURDAY NIGHT. THE
DGEX IS A CONSENSUS BETWEEN THE OTHERS. WILL JUST USE CONSENSUS
GRIDS FOR THE FORECAST.

&&

.HYDROLOGY...HEAVY RAINFALL FELL NORTH OF A PORT WASHINGTON TO
SUN PRAIRIE TO MINERAL POINT LINE WHERE TO 2 4 INCHES OF RAIN FELL
YESTERDAY AFTERNOON AND LAST NIGHT.

LOW PRESSURE WILL MOVE NORTHEAST ALONG A FRONTAL BOUNDARY JUST TO
THE SOUTH OF WISCONSIN.  THE LOW WILL REACH NORTHERN ILLINOIS BY
MIDNIGHT AND INTO LOWER MICHIGAN DURING THE EARLY MORNING HOURS.  AN
ADDITIONAL 1 TO 2 INCHES OF RAINFALL IS EXPECTED IN THE AREA THAT
RECEIVED THE HEAVY RAIN LAST NIGHT.  WIDESPREAD 2 INCH TOTALS ARE
EXPECTED OVER SOUTH AREAS INCLUDING MADISON...MILWAUKEE...RACINE AND
KENOSHA.

MODERATE RAINS WERE PUSHING NORTHEAST INTO SOUTHERN WISOCNSIN THIS
AFTERNOON. THIS ADDED RAIN WILL LIKELY SEND MANY RIVERS INTO
FLOOD. SOME RIVERS MAY EVEN REACH MAJOR FLOOD CATEGORY...LIKE THE
SHEBOYGAN RIVER...AND MILWAUKEE RIVER AT CEEDARBURG.

FLOOD WATCHES ARE IN EFFECT INTO MONDAY MORNING. SOME RIVER FLOOD
WARNINGS HAVE ALSO BEEN ISSUED.

&&

.AVIATION/00Z TAFS/...

.AVIATION/00Z TAFS/...LOW PRESSURE WILL TRACK FROM THE CENTRAL
PLAINS TO EASTERN LOWER MI BY MONDAY MORNING. MODERATE TO HEAVY RAIN
WILL BE WIDESPREAD ACROSS SRN WI WITH THIS TRACK. INITIAL MOISUTRE
SURGE AHEAD OF THE LOW SPREADING RAIN IN INTO THIS EVENING. SOME
DENSE FOG HAS MOVED ONSHORE AND THIS WILL AFFECT KMKE AND KENW INTO
THE EVENING. ONCE WINDS RAMP UP AND RAIN BEGINS EXPECT SOME
DISPERSION OF THE THICKER FOG. IFR AND SOME LIFR CIGS WILL BE
PREVALENT THROUGH TONIGHT. WITH COLDER AIR WRAPPING INTO THE SYSTEM
LATER TONIGHT...EXPECTING A MIX AND CHANGEOVER TO OCCUR WHICH WILL
RESULT IN SOME LIGHT ACCUMULATIONS...ESPECIALLY NORTHWEST OF KUES
AND NORTH OF KMSN. GUSTY NNE WINDS WILL TRANSITION TO MORE OF NNW
WIND FOR MONDAY AND REMAIN BLUSTERY. CIGS LIKELY TO TRANSITION MORE
TO MVFR AS HEAD INTO THE LATE MORNING AND AFTERNOON HOURS.

&&

.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FOR TONIGHT THROUGH
MONDAY DUE TO BRISK NORTHERLY WINDS IN THE WAKE OF A DEPARTING LOW
PRESSURE SYSTEM. PRIOR TO THE ARRIVAL OF THE GUSTIER WINDS...A
BAGGIER GRADIENT WITH LIGHT FLOW OFF THE LAKE HAS RESULTED IN SOME
DENSE FOG FORMATION SO ADVISORY FOR THIS THROUGH THE EARLY EVENING
HOURS.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH MONDAY MORNING
     FOR WIZ063>072.

     FLOOD WATCH THROUGH MONDAY MORNING FOR WIZ046-047-051-052-
     056>060-062.

LM...DENSE FOG ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ643>646.

     SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT MONDAY
     FOR LMZ643>646.

&&

$$

TONIGHT/MONDAY AND AVIATION/MARINE...COLLAR
MONDAY NIGHT THROUGH SUNDAY...HENTZ



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