Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 160259 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
859 PM CST MON DEC 15 2014

.UPDATE...
A BREAK DURING THE EARLY EVENING IN THE DENSE FOG AS VSBYS ROSE
WITH STEADIER RAIN AND LIFT WITH VORT MAX PASSING THROUGH. BAND OF
HIGHER REFLECTIVITY SHOWERS ON RADAR OFFSHORE IN LINE WITH
ENHANCED LOW-LEVEL FRONTOGENESIS THAT LIFTS NORTH WITH VORT MAX.
HRRR AND 00Z NAM VSBY FORECASTS INDICATE 1/4 MILE OR LESS VSBYS
MOVE BACK IN TO THE LAKE SHORE COUNTIES BETWEEN 03Z AND 06Z WITH
BAGGY GRADIENT ASSOCIATED WITH THE SURFACE LOW AND INCREASED
SURFACE DEW POINTS...CONTINUING THROUGH THE OVERNIGHT. WILL HAVE
TO WATCH ADJOINING COUNTIES TO THE WEST FOR INCLUSION BASED ON NAM
FORECASTS. WILL LEAVE DENSE FOG ADVISORY AS IS.

&&

.AVIATION/06Z TAFS/...

PERIOD OF STEADIER RAIN BROUGHT VSBYS UP TO MVFR LEVELS THOUGH
IFR CIGS CONTINUE. NAM AND HRRR VSBY FORECASTS SHOW IFR VSBYS IN
FOG RETURNING BETWEEN 03Z AND 06Z AND LASTING THROUGH THE
OVERNIGHT...WITH IMPROVEMENT FROM WEST TO EAST REACHING THE
EASTERN TAF SITES AROUND/SHORTLY AFTER 12Z WITH COLDER...DRIER
AIR ADVECTING IN ON GUSTY NW WINDS BEHIND COLD FRONT. CIGS WILL BE
SLOWER TO RISE...WITH CIGS NOT EXPECTED TO REACH 1K FT OR HIGHER
UNTIL 21Z TO 00Z...AND MVFR LEVELS TOWARD THE END OF THE FORECAST
PERIOD.

&&

.MARINE...
MARINE DENSE FOG ADVISORY CONTINUES UNTIL 12Z TUESDAY...WITH VSBYS
RISING WITH COLDER...DRIER AIR ADVECTING IN ON INCREASING NW
WINDS BEHIND A COLD FRONT. A SMALL CRAFT ADVISORY WILL LIKELY BE
NEEDED FOR TUESDAY AFTERNOON AND EVENING AS THESE NW WINDS RISE TO
15 TO 25 KNOTS. THE OFFSHORE FETCH WILL KEEP HIGHER WAVES TOWARD
OPEN WATER.

&&

.PREV DISCUSSION... /ISSUED 411 PM CST MON DEC 15 2014/

TONIGHT AND TUESDAY...FORECAST CONFIDENCE...HIGH

PERIODIC RAIN SHOWERS WILL CONTINUE THROUGH THE NIGHT AS LOW
PRESSURE PASSES OVER NORTHERN ILLINOIS. EXPECT FOG TO DEVELOP AGAIN
ACROSS THE REGION. SOUNDINGS INDICATE A SATURATED ENVIRONMENT FROM
THE SURFACE TO MIDLEVELS THROUGH TUES MORNING. FOG MAY BE DENSE
AFTER MIDNIGHT MAINLY ACROSS THE SOUTHEAST WHERE ONSHORE FLOW THIS
EVENING WILL CONTRIBUTE TO ADDITIONAL MOISTURE.

COLD AIR ADVECTION ERODES LOW LEVEL INVERSION THIS EVENING AND
PROFILE IS ISOTHERMAL UP TO ABOUT 2000 FT. LITTLE CHANGE IN
OVERNIGHT TEMPERATURES EXPECTED FROM EVENING LOWS AND HIGH TEMPS
WILL OCCUR TUES MORNING AS COLD AIR ADVECTION CONTINUES DURING THE
DAY. TEMPERATURES ARE EXPECTED TO DROP TO NEAR FREEZING DURING THE
AFTERNOON SO A TRANSITION TO A RAIN/SNOW MIX IS EXPECTED AROUND
MIDDAY IN SOUTH-CENTRAL WI AND LATE AFTERNOON IN THE SOUTHEAST. A
FEW HOURS OF LIGHT SNOW IS POSSIBLE ON THE BACK EDGE OF PRECIP
WITH LITTLE TO NO ACCUMULATION.

BEHIND THE DEPARTING LOW WINDS WILL SHIFT NORTHWEST AND
INCREASE. MID LEVELS WILL BE DRYING ON TUES BEHIND THE COLD FRONT
BUT SOUNDINGS SHOW LOW LEVEL MOISTURE LINGERING. HENCE CLOUDS WILL
CONTINUE AFTER PRECIPITATION ENDS.

TUESDAY NIGHT THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE
MEDIUM TO HIGH.

BRISK NWLY WINDS AND COLD ADVECTION TO CONTINUE TUE NT AND WED AS
THE UPPER TROUGH CURRENTLY OVER MANITOBA AND W ONTARIO CANADA
MOVES SEWD ACROSS THE STATE. 850 MB TEMPS TO DROP TO -10C BY 18Z
WED. THE COLD POOL WILL MOVE AWAY BY THU WITH POLAR HIGH PRESSURE
TO THEN PREVAIL OVER THE UPPER MS RIVER VALLEY.

THE SFC TEMPS WILL DEPEND ON CLOUD COVER WHICH IS UNCERTAIN. THE
TYPICAL MOIST LOW LEVELS OF THE NAM HANGS ONTO THE STRATUS RIGHT
INTO THU WHILE THE GFS SOUNDINGS SUGGEST MORE PTLY CLOUDY
CONDITIONS WITHIN THE COOLER AND DRIER AIRMASS. GIVEN NO SNOW
COVER...ANY SUNSHINE WILL AID IN MILDER TEMPS THAN WHAT MAY BE
EXPECTED. BELIEVE BROKEN STRATUS ARE LIKELY AT TIMES WITH THE
UPPER TROUGH PASSAGE ON WED ESPECIALLY OVER CENTRAL WI...THEN
TRENDING MORE PARTLY CLOUDY INTO THU. DID TREND A LITTLE ON THE
MILD SIDE FOR HIGH TEMPS BUT LOW TEMPS HAVE THE POTENTIAL TO BE
COLDER IF CLEARING HOLDS LONG ENOUGH AT NIGHT.

LONG TERM...FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM.

THE WRN GREAT LAKES WILL REMAIN BETWEEN THE NRN AND SRN JET
STREAMS WITH LITTLE FLOW ALOFT. A N-S SFC RIDGE WILL PREVAIL OVER
THE REGION DURING THIS TIME WITH SLOWLY RISING HIGH TEMPS IN THE
30S.

AVIATION/00Z TAFS/...

EXPECT MAINLY IFR CONDITIONS OR LESS TO CONTINUE THROUGH TUES
MORNING. DENSE FOG IS LIKELY AT TIMES AT MKE AND ENW DUE TO A
MOIST SOUTHEAST FLOW. IT MAY ALSO DEVELOP AT MSN AND UES BUT THERE
IS MORE UNCERTAINTY AT THE THESE LOCATIONS.

WINDS WILL INCREASE TUESDAY AND SHIFT TO THE NORTHWEST WHICH WILL
HELP SCOUR OUT LOW CLOUDS SOMEWHAT IN THE AFTERNOON. MAY SEE NEAR
MVFR CONDITIONS LATE TUES AFTERNOON AT MSN THEN SPREADING TO EASTERN
TAF SITES.

PERIODIC RAIN SHOWERS EXPECTED THROUGH TUES MORNING. EXPECTING A
TRANSITION TO A RAIN/SNOW MIX MIDDAY WITH SOME LIGHT SNOW SHOWERS
POSSIBLE LATE IN THE AFTERNOON AT MSN AND EARLY EVENING AT EASTERN
TAF SITES. NO SNOW ACCUMULATION EXPECTED.

MARINE...

ONSHORE WINDS AND RELATIVELY HIGH LOW LEVEL MOISTURE WILL RESULT
IN PERSISTENT DENSE FOG ACROSS THE NEARSHORE WATERS THROUGH
TONIGHT. WINDS WILL SHIFT OFFSHORE TUESDAY MORNING...LIKELY
BRINGING DRIER AIR AND AN END TO THE DENSE FOG.

NORTHWEST WINDS WILL BECOME GUSTY BY TUESDAY AFTERNOON...WITH
HIGHER WINDS PERSISTING INTO THE NIGHT. A SMALL CRAFT ADVISORY
WILL LIKELY BE NEEDED FOR THIS PERIOD.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 7 AM CST TUESDAY FOR WIZ052-060-066-071-
     072.

LM...DENSE FOG ADVISORY UNTIL 7 AM CST TUESDAY FOR LMZ643>646.

&&

$$

UPDATE...REM
TONIGHT/TUESDAY AND AVIATION/MARINE...SM
TUESDAY NIGHT THROUGH MONDAY...DAVIS



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