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000
FXUS63 KMKX 181630 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1130 AM CDT SAT MAY 18 2013

.UPDATE...

IT IS DIFFICULT TO TRACK THE LOW CLOUDS ON SATELLITE IMAGERY TODAY
DUE TO THE HIGH CLOUDS STREAMING OVER THEM. HOWEVER...THERE IS A
DISCERNIBLE AREA OF LOW CLOUDS...CONFIRMED BY ASOS/AWOS
OBSERVATIONS...FROM MADISON UP TO JUNEAU AND OVER TO WEST BEND THAT
IS SHIFTING NORTH WITH TIME. CUMULUS CLOUDS HAVE RECENTLY DEVELOPED
OVER SOUTH CENTRAL WI IN AREAS WHERE THE DEWPOINTS ARE ABOUT 59F AND
HIGHER.

THIS HELPS TO DISTINGUISH THE BOUNDARY BETWEEN LAKE-INFLUENCED DRIER
AIR WITH EASTERLY WINDS AND THE STREAM OF MOISTURE FEEDING INTO
SOUTH CENTRAL WI ON SOUTHERLY WINDS. EXPECTING THIS MOIST AIR TO
SPREAD NORTH AND WEST OF MADISON UP TO THE DELLS...BUT NOT SURE
EXACTLY HOW FAR EAST IT WILL GET. IN THE AREA OF CUMULUS
CLOUDS...RAP SOUNDINGS SHOW A SMALL AMOUNT OF CAPE...BUT THE DEPTH
OF THE MOIST LAYER LOOKS VERY SHALLOW. THE 14Z HRRR MODEL NOW BRINGS
LIGHT SHOWERS/TSTORMS BACK INTO AREAS OF SOUTH CENTRAL AND CENTRAL
WI THIS AFTERNOON...SO NOT GIVING UP ON THE SMALL POPS IN OUR
FORECAST.

&&

.AVIATION/18Z TAFS/...

FUEL ALTERNATE CLOUDS...WEAKLY DISCERNIBLE ON VISIBLE SATELLITE
IMAGERY AND CONFIRMED BY ASOS/AWOS OBSERVATIONS FROM MADISON UP TO
JUNEAU AND OVER TO WEST BEND...WILL SHIFT NORTH WITH TIME TODAY.
MVFR CUMULUS CLOUDS HAVE RECENTLY DEVELOPED OVER SOUTH CENTRAL WI IN
AREAS WHERE THE DEWPOINTS ARE ABOUT 59F AND HIGHER.

THIS HELPS TO DISTINGUISH THE BOUNDARY BETWEEN LAKE-INFLUENCED DRIER
AIR WITH EASTERLY WINDS AND THE STREAM OF MOISTURE FEEDING INTO
SOUTH CENTRAL WI ON SOUTHERLY WINDS. EXPECTING THIS MOIST AIR TO
SPREAD NORTH AND WEST OF MADISON UP TO THE DELLS...BUT NOT SURE
EXACTLY HOW FAR EAST IT WILL GET. IN THE AREA OF CUMULUS CLOUDS...
RAP SOUNDINGS SHOW A SMALL AMOUNT OF CAPE...BUT THE DEPTH OF THE
MOIST LAYER LOOKS VERY SHALLOW. THE 14Z HRRR MODEL NOW BRINGS
LIGHT SHOWERS AND ISOLATED TSTORMS BACK INTO AREAS OF SOUTH CENTRAL
AND CENTRAL WI THIS AFTERNOON...SO NOT GIVING UP ON THE SMALL POPS
IN OUR FORECAST. WILL ADD MENTION OF -SHRA BACK INTO MSN TAF.

FOG MAY BE MORE PREVALENT TONIGHT DUE TO LIGHT BOUNDARY LAYER MIXING
BUT TOO MUCH UNCERTAINTY REGARDING CLOUD COVER TO INCLUDE MORE THAN
MVFR VSBYS AT THIS POINT.

&&

.PREV DISCUSSION... /ISSUED 320 AM CDT SAT MAY 18 2013/

AVIATION/12Z TAFS/...BOUNDARY LAYER MIXING AND MOIST LOW TO MID LEVELS
HAS ALLOWED PATCHY LOW CLOUDS TO DEVELOP BY LAKE MI LAST HOUR. WL
LIKELY CONTINUE FOR SEVERAL MORE HOURS AND MAY EXPAND FARTHER
WEST...BUT LOW LEVEL CONVERGENCE WL DIMINISH AS WINDS BEGIN TO
VEER THROUGH THE EARLY MRNG. HENCE WL RETURN TO VFR CONDITIONS BY
MID-MORNING. SOME LIGHT FOG MAY ACCOMPANY LOW CLOUDS BUT BOUNDARY
LAYER MIXING SHOULD PREVENT MORE SIGNIFICANT FOG. FOG MAY BE MORE
PREVALENT TONIGHT DUE TO LIGHT BOUNDARY LAYER MIXING BUT TOO MUCH
UNCERTAINTY REGARDING CLOUD COVER TO INCLUDE MORE THAN MVFR VSBYS
AT THIS POINT.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...COLLAR
SUNDAY THROUGH FRIDAY...MBK