Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 101652 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1152 AM CDT THU APR 10 2014

.UPDATE...LIGHT RAIN SHOWERS/SPRINKLES...ASSOCIATED WITH 850 MB
TO 700 MB FRONTOGENESIS RESPONSE FIELDS...WERE MOVING EAST
NORTHEAST THROUGH THE NORTHEASTERN PORTIONS OF THE FORECAST AREA.
NOT MUCH GROUND TRUTH WAS OBSERVED WITH THESE SHOWERS/SPRINKLES AS
THEY MOVED THROUGH. DRY AIR BELOW 10000 FEET WAS LIMITING A FAIR
AMOUNT OF THE PRECIPITATION FROM REACHING THE SURFACE. THIS SHOULD
MOVE OUT OF THE AREA BY 18Z THURSDAY.

COLD FRONT EXITING THE SOUTHEAST COUNTIES...WITH WINDS VEERING
NORTHWEST BEHIND IT. GOOD LOW LEVEL MIXING WILL ALLOW FOR GUSTS TO
AROUND 20 KNOTS DURING THE AFTERNOON. MID LEVEL CLOUDS WILL
GRADUALLY MOVE OUT OF THE AREA...WITH AT LEAST PARTIAL SUNSHINE BY
MID AFTERNOON. 925 MB TEMPERATURES AND GOOD MIXING SUGGEST HIGHS
SHOULD REACH THE UPPER 50S TO LOWER 60S.

&&

.AVIATION/18Z TAFS/...VFR CONDITIONS ARE EXPECTED THIS
AFTERNOON...TONIGHT AND FRIDAY ACROSS TAF SITES. NORTHWEST WINDS
WILL REMAIN THIS AFTERNOON...GUSTING TO AROUND 20 KNOTS AT TIMES.
MID LEVEL CLOUDS WILL GRADUALLY MOVE OUT OF THE AREA DURING THIS
TIME.

LIGHT AND VARIABLE WINDS THIS EVENING WILL BECOME LIGHT AND
SOUTHERLY LATER TONIGHT...AS HIGH PRESSURE PASSES BY TO THE
SOUTHWEST. SOUTHWEST WINDS ARE EXPECTED ON FRIDAY...WITH GUSTS TO
AROUND 20 KNOTS IN THE LATE MORNING AND AFTERNOON. SCATTERED
CLOUDS AROUND 6000 FEET ABOVE GROUND LEVEL ARE EXPECTED IN THE
AFTERNOON.

&&

.MARINE...NORTHWEST WINDS BEHIND THE PASSING COLD FRONT THIS
AFTERNOON WILL GUST TO AROUND 20 KNOTS AT TIMES. A SMALL CRAFT
ADVISORY WILL NOT BE NEEDED.

A SMALL CRAFT ADVISORY MAY BE NEEDED SUNDAY NIGHT AND MONDAY...AS
LOW PRESSURE PASSES BY THE SOUTHEAST OF THE AREA. THE TIGHT
PRESSURE GRADIENT SHOULD RESULT IN GUSTY NORTH TO NORTHEAST WINDS
AND HIGH WAVES.

&&

.FIRE WEATHER...DEEP MIXING BEHIND COLD FRONT WILL BRING VERY LOW
RELATIVE HUMIDITY VALUES IN THE 20 TO 30 PERCENT RANGE ACROSS MOST
OF THE AREA AGAIN THIS AFTERNOON...EXCEPT IN FAR SOUTHEAST
WISCONSIN. NORTHWEST WINDS BEHIND COLD FRONT IN THE AFTERNOON MAY
GUST TO 20 TO 25 MPH. TEMPERATURES WILL REMAIN IN THE UPPER 50S
TO LOWER 60S.

DEEP MIXING WITH MILDER AIR MOVING INTO THE REGION FOR FRIDAY WILL
BRING VERY LOW RELATIVE HUMIDITY VALUES IN THE 25 TO 30 PERCENT
RANGE. SOUTHWEST WINDS WILL GUST TO 20 TO 25 MPH AT TIMES. HIGH
TEMPERATURES WILL BE IN THE MIDDLE 60S...WITH A FEW UPPER 60S
POSSIBLE IN SOUTH CENTRAL WISCONSIN.

WILL HIGHLIGHT THE EXPECTED VERY LOW RELATIVE HUMIDITY VALUES AND
GUSTY WINDS ON FRIDAY WITH THE AFTERNOON FIRE WEATHER FORECAST
ISSUANCE.

&&

.PREV DISCUSSION... /ISSUED 341 AM CDT THU APR 10 2014/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

977 MB SFC LOW IN WRN ONTARIO WITH A SFC TROUGH EXTENDING TO THE
SOUTHWEST THROUGH NW WI/SE MN/NW IA. GETTING A DUCTED GRAVITY WAVE
ALONG SFC WIND SHIFT THAT IS SHOWING UP AS PARALLEL BANDS ON
REGIONAL RADARS. SCATTERED RETURNS ON RADAR ALONG TROUGH ONLY
PRODUCING 10SM LIGHT SHOWERS/SPRINKLES UNDER 9K TO 10K FT CLOUD
DECK. ALSO HAVING TROUBLE GETTING GROUND TRUTH UNDER MORE IMPRESSIVE
NARROW BAND OF PCPN ON REGIONAL RADAR MOSAICS JUST BEHIND TROUGH
ALONG COLD FRONT.

MODEL TRENDS HAVE BEEN PICKING UP ON DRY AIR IN PLACE AND CUTTING
BACK ON AREAL COVERAGE AND INTENSITY...AND EVEN THOUGH THERE IS A
STRONG 850-700 MB FRONTOGENETIC RESPONSE...HAVE CONTINUED DOWNWARD
POP ADJUSTMENTS FROM PREVIOUS SHIFT.

POST-FRONTAL MIXING UP TO AROUND 730 MB AND SOME SUNSHINE THIS
AFTERNOON...ESPECIALLY IN THE NW HALF...ALLOWS TEMPS TO RECOVER INTO
THE LOWER 60S WEST. LOOKING AT MID TO UPPER 50S EAST WITH CLOUDS
HANGING ON INTO THE MID-AFTERNOON. SFC DEW POINTS FALL INTO THE LOW
TO MID 20S. LOOKING AT POST-FRONTAL WINDS GUSTING TO AROUND 20 MPH.

QUIET TONIGHT WITH RIDGE OF SFC HIGH PRESSURE OVER SRN WI. WINDS
LIGHTEN EARLY THEN TURN SRLY AROUND 5 MPH. ALONG WITH MID-HIGH LEVEL
WARM ADVECTION CLOUDS SPREADING IN AFTER MIDNIGHT PREVENTING FULL
RADIATIONAL COOLING...EXPECTING LOWS IN THE MID-UPPER 30S.

FRIDAY - CONFIDENCE...MEDIUM
SHORTWAVE TROUGH AFFECTS MAINLY NRN WI THOUGH AN EXTENSION OF THE
VORT SWINGS THROUGH SRN WI DURG THE AFTN. BUFKIT SOUNDINGS SHOW
LOW LEVEL INVERTED V STRUCTURE WITH VARYING DEGREES OF MID LEVEL
MOISTURE. MOISTURE PROFILE LOOKS MORE SUPPORTIVE OF PRECIP IN THE
FAR NRN CWA. THE GEM MORE GENEROUS CWA WIDE FOR LIGHT PRECIP
WHILE THE GFS/ECMWF AND NAM SUGGEST A MORE GLANCING SHOT. WILL
CONFINE AFTN POPS TO TO THE FAR NRN CWA FOR NOW. 925 TEMPS
SUPPORTIVE OF LOW/MID 60S FOR HIGHS.

SATURDAY AND SATURDAY NIGHT - CONFIDENCE...MEDIUM
UNSETTLED PERIOD AS UPPER FLOW TURNS SOUTHWEST AND LOW PRESSURE
APPROACHES FROM THE PLAINS. WARM AIR/MOISTURE ADVECTION WILL
LIKELY RESULT IN SHRA DEVELOPMENT DURING THE DAY WITH POTENTIAL
FOR TSRA SAT NGT. SHORTWAVE NOTED IN THE SW UPR FLOW AND APPROACHING
FRONTAL BOUNDARY WILL AID IN VERTICAL MOTION. THERE IS ALSO A
SIGNIFICANT UPPER LEVEL DIVERGENCE SIGNATURE ASSOCIATED WITH RIGHT
REAR QUADRANT OF JET CORE SITUATED TO THE NORTH AND NORTHEAST OF
WI. 00Z MODEL RUNS FOCUS BETTER CONVECTIVE DEVELOPMENT FROM IA
INTO PORTIONS OF NW WI DURG THE AFTN WITH THIS ACTIVITY ROLLING
INTO SRN WI SAT NGT. THIS IN ASSOCIATION WITH SURFACE/850 FRONTS
DRAWING CLOSER FROM THE NW SAT NGT.

SUNDAY AND MONDAY - CONFIDENCE...LOW
ATTENTION THEN TURNS BACK TO THE CENTRAL PLAINS FOR THE PROGRESSION
OF THE SECONDARY LOW TOWARDS THE NORTHEAST. 00Z ECMWF HAS THE LOW
IN NW INDIANA BY 12Z MONDAY WHILE THE GEM AND GFS ARE SHOWING A
TRACK THROUGH CENTRL/SRN INDIANA. 850 BAROCLINIC TIGHTENS UP
ACROSS THE CWA SUNDAY AND THIS WILL MAINTAIN RAIN/THUNDER POTENTIAL.
AS THE LOW SHIFTS EAST SUNDAY NIGHT/MONDAY...COLDER AIR GETS DRAWN
AS NORTH WINDS INCREASE. THE GFS SHOWS LESS MIX/SNOW POTENTIAL.
THE ECMWF KEEPS SHOWS LARGEST AMOUNT OF QPF WITHIN THE COLDER
AIRMASS LONGEST. THE GFS SHOWS EVEN LESS SNOW POTENTIAL DUE TO
LOWER QPF WITH THE MORE SEWD TRACK. AT THIS TIME THE GEM SOLUTION
IS A COMPROMISE OF THE ECMWF AND GFS. STILL LIKE THE IDEA OF
MENTIONING AT LEAST SOME LIGHT ACCUMS AT THIS POINT EVEN THOUGH
CONSIDERABLE MODEL VARIABILITY EXISTS WITH RESPECT TO THE EXTENT
OF PRECIP ON THE COLD SIDE OF SYSTEM.

TUESDAY - CONFIDENCE...MEDIUM
UPPER TROUGH WILL BE SHIFTING AWAY. ECMWF DIGS MORE SHORTWAVE
ENERGY ON THE BACK SIDE OF THE TROUGH INTO SRN WI...WHILE THE GFS
KEEPS THIS VORT MORE ELONGATED ACRS NRN WI. WILL STICK WITH THE
ALLBLEND POPS AT THIS TIME. BELOW NORMAL TEMPS EXPECTED.

WEDNESDAY - CONFIDENCE...LOW
PROGS AGREE ON SOME MID LEVEL RIDGING TAKING HOLD. IN THE LOWER
LEVELS THE ECMWF...AND TO A LESSER EXTENT THE GFS...SHOW HIGH
PRESSURE IN CONTROL. THE GFS SUGGESTS AN ELONGATED STRIP OF
ISENTROPIC PRECIP EXTENDING INTO SRN WI. ALLBLEND TAKES THE
COMPROMISE APPROACH AND WILL FOLLOW THOUGH WOULD LEAN A BIT
TOWARDS THE DRIER SETUP PRESENTED BY THE ECMWF.

AVIATION/12Z TAFS/...LOOKING AT LOW-LEVEL WIND SHEAR CONDITIONS
TO END BETWEEN 13Z AND 14Z AS WINDS JUST OFF THE DECK EASE WITH
PASSAGE OF MID-LEVEL TROUGH. LOOKING AT SCATTERED LIGHT SHOWERS...
SPRINKLES AS COLD FRONT MOVES THROUGH THIS MORNING...WITH VFR
CLOUDS/VSBYS. NW WINDS BEHIND THE FRONT WILL GUST IN THE 20-25 KT
RANGE FOR A TIME.

WINDS EASE AND SKIES SCATTER OUT LATER THIS AFTERNOON/EVENING...WITH
VFR CONDITIONS EXPECTED FOR THE REMAINDER OF THE FORECAST.

MARINE...SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT UNTIL 15Z
ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN...WITH WINDS EASING
AS SURFACE TROUGH/COLD FRONT MOVE THROUGH THE REGION. STILL
LOOKING AT SWLY WIND GUSTS OF 25 TO 30 KNOTS NEAR THE SHORE UNTIL
TROUGH MOVES CLOSER...WITH INVERSION HOLDING GUSTS LOWER TOWARD
OPEN WATER.

WINDS WILL VEER NORTHWEST TO WEST BEHIND THE COLD FRONT THIS AFTERNOON...
GUSTING TO AROUND 20 KNOTS. WAVES SHOULD SUBSIDE AS WINDS BECOME
OFFSHORE. WINDS WILL THEN SUBSIDE FURTHER TONIGHT.

FIRE WEATHER...DEEP MIXING BEHIND COLD FRONT WILL BRING VERY LOW
RELATIVE HUMIDITY VALUES BELOW 30 PCT AGAIN TODAY...EXCEPT IN FAR
SOUTHEAST WISCONSIN. NORTHWEST WINDS BEHIND COLD FRONT IN THE AFTERNOON
MAY GUST TO 20 TO 25 MPH. TEMPERATURES WILL REMAIN IN THE UPPER 50S
TO LOWER 60S. WILL HIGHLIGHT THE EXPECTED VERY LOW RELATIVE HUMIDITY
VALUES AND GUSTY WINDS IN THE FIRE WEATHER FORECAST.

&&

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

$$

UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...REM
FRIDAY THROUGH WEDNESDAY...COLLAR



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