Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

000
FXUS63 KMKX 260249 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
949 PM CDT MON APR 25 2016

.UPDATE...

AXIS OF HIGHER DEW POINTS HAS SHIFTED EAST OF AREA AHEAD OF
SURFACE LOW NOW CENTERED OVER SRN LAKE MICHIGAN ENDING THE SEVERE
WEATHER THREAT. AN ISOLATED SHOWER STILL POSSIBLE LATE THIS
EVENING ALONG COLD FRONT/SURFACE TROUGH AS IT SAGS THROUGH THE
REMAINDER OF THE CWA OVERNIGHT IN THE WAKE OF THE LOW. MOSTLY
CLEAR SKIES WILL BE REPLACED BY STRATUS DECK BEHIND THE COLD
FRONT. LATEST NAM SUPPORTS GOING FORECAST WITH EVERYONE FALLING
INTO THE 40S BY MORNING ON NORTH TO NORTHEAST WINDS.

&&

.AVIATION/06Z TAFS/...

LOOKING FOR VFR CONDITIONS UNTIL IFR STRATUS OVERSPREADS ALL OF
SOUTHERN WISCONSIN LATE TONIGHT BEHIND A COLD FRONT/SURFACE TROUGH
THAT IS CURRENTLY ALONG A WEST BEND...JUNEAU...PORTAGE TO THE
DELLS LINE. CURRENT TIMING BRINGS THE LOW CLOUDS DOWN TO A LONE
ROCK...MADISON TO MILWAUKEE LINE AROUND 0430Z TO 05Z...AND TO THE
ILLINOIS BORDER BETWEEN 06Z AND 07Z...WITH THE LATER TIME OVER THE
SW. COULD SEE SOME LOCATIONS DROP TO BELOW ALTERNATE MINIMUMS IN
THE EAST WITH THE COOL NORTH TO NORTHEAST FLOW OFF OF LAKE
MICHIGAN ALONG WITH SOME PATCHY DRIZZLE. SHOULD LIFT CLOUDS BACK
UP TO MVFR LEVELS OVER WESTERN AREAS AROUND MID-MORNING...BUT
EASTERN LOCATIONS WILL NOT REACH THOSE LEVELS UNTIL MIDDAY OR
EARLY AFTERNOON. EXPECT VFR CIGS BY EARLY AFTERNOON WEST AND LATE
AFTERNOON EAST.

&&

.MARINE...

SLOW MOVEMENT OF SURFACE TROUGH/COLD FRONT WILL KEEP NORTHERLY
GUSTS FROM REACHING SMALL CRAFT ADVISORY LEVELS UNTIL AFTER 08Z IN
THE NORTH AND 11Z OR 12Z IN THE SOUTH. CURRENT TIMING OF SMALL
CRAFT ADVISORIES LOOKS ON TRACK AND SUPPORTED BY LATEST NAM
SOUNDINGS.

&&

.PREV DISCUSSION... /ISSUED 517 PM CDT MON APR 25 2016/

UPDATE...

SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 10 PM.

WHEN THUNDERSTORMS HIT THE LAKE BREEZE... WE ARE SEEING A BRIEF
UPTICK IN STORM STRENGTH/GROWTH. THIS IS DUE TO THE STORMS GETTING A
LITTLE EXTRA LIFT. THEY TEND TO DROP LARGER THAN PEA SIZE HAIL JUST
EAST OF THE LAKE BREEZE.

THE THUNDERSTORMS ARE PULSE-LIKE AND TYPICAL OF SINGLE CELL STORMS.
WE ARE SEEING VERY FEW STORMS THAT SHOW PERSISTENT MID LEVEL
ROTATION. MANY OF THE STORMS ARE DEVELOPING WHERE CAPE IS ONLY
AROUND 500 J/KG AND 0-6KM SHEAR IS 40 TO 50 KNOTS.

THERE IS STILL POTENTIAL FOR THUNDERSTORMS TO REACH SEVERE
CRITERIA... ESPECIALLY WITH HAIL. THE INSTABILITY WILL HANG AROUND
SOUTHEAST WI UNTIL ONE MORE FRONT MOVES THROUGH... PROBABLY CLEARING
SOUTHEAST WI BY 10 PM. WE DROPPED THE WATCH FOR DANE... COLUMBIA AND
GREEN COUNTIES SINCE THERE IS MORE DRY AIR IN THAT AREA. MESO MODELS
KEEP CONVECTION CONFINED MAINLY IN EASTERN WI.

PREV DISCUSSION... /ISSUED 337 PM CDT MON APR 25 2016/

LATE THIS AFTERNOON...

SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 10 PM.

CONVECTION DEVELOPED SLIGHTLY EARLIER THAN ANTICIPATED. THEY ARE
FOCUSING ALONG A SURFACE FRONT DEFINED BY A WIND DIRECTION CHANGE
FROM SOUTH TO SW WITHIN THE LEADING GRADIENT BETWEEN HIGHEST CAPE
AND LOWER CAPE. BULK SHEAR OF 40 TO 50 KNOTS IS SUFFICIENT FOR HAIL.
WE HAVE HAD SEVERAL REPORTS OF LESS THAN ONE INCH HAIL SO FAR.

THE OTHER AREA OF INTEREST IS TOWARD FOND DU LAC AND SHEBOYGAN WHERE
THE WARM FRONT IS MEETING UP WITH THE PERSISTENT COLD NORTHEAST FLOW
OFF LAKE MICHIGAN. THE FRONT WITH THE WIND SHIFT IS MEETING UP WITH
THESE TWO FRONTAL BOUNDARIES AND THUNDERSTORMS ARE CONTINUOUSLY
DEVELOPING. THERE IS HIGH 0-1KM SHEAR AROUND 20 KT IN THIS AREA
ALTHOUGH LOWER CAPE. THIS IS THE AREA THAT WILL NEED TO BE WATCHED
CLOSELY FOR A POSSIBLE TORNADO.

THERE SHOULD BE MORE CONVECTION DEVELOPING IN SOUTH CENTRAL WI WITH
ANOTHER WEAK FRONT/DRY LINE APPROACHING. CAPE WILL LIKELY BE HIGHER
WITH THIS NEXT ROUND IF IT DEVELOPS AND THERE IS A LARGER HAIL
THREAT. THESE ADDITIONAL THUNDERSTORMS ARE EXPECTED TO EVOLVE INTO
MORE OF A LINE LATER THIS AFTERNOON. THERE IS A LAKE BREEZE
INFLUENCE WHICH INCREASES THE 0-1KM SHEAR.

PER THE LATEST HRRR MODEL AND OTHER MESOSCALE MODELS...
THUNDERSTORMS SHOULD NOW BE OUT OF SOUTHEAST WI BY 7 PM OR 8 AT THE
LATEST.

TONIGHT AND TUESDAY...

A COLD FRONT WILL SLIDE SOUTHWESTWARD THROUGH SOUTHERN WI LATE
TONIGHT AND BRING LOW CLOUDS AND BRISK NORTH TO NORTHEAST WINDS.
THERE IS 2000 TO 3000 FEET THICK LAYER OF SATURATION WITH THE LOW
CLOUDS WHICH COULD BE SUFFICIENT FOR DRIZZLE THROUGH MID TUE
MORNING.

TUESDAY NIGHT...FORECAST CONFIDENCE IS HIGH.

A MID LEVEL SHORT WAVE RIDGE AXIS WILL DRIFT OFF TO THE
EAST...ALLOWING THE NEXT CIRCULATION TO BEGIN IMPINGING ON
SOUTHWEST WISCONSIN TOWARD SUNRISE ON WED. MOST OF THE NIGHT
SHOULD BE DRY...WITH A CHANCE SNEAKING INTO THE FAR SOUTHWEST
AFTER 4 AM.

WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE IS MEDIUM.

A DECENT BAND OF PRECIP SHOULD DEVELOP WITHIN A DEEP AND
PRONOUNCED TROUGH AXIS DRIFTING ACROSS THE UPPER MIDWEST. THE MID
LEVEL SYSTEM IS DISPLACED QUITE A BIT FARTHER NORTH COMPARED TO
THE SURFACE LOW WHICH WILL DRIFT ACROSS CNTRL AND SRN IL LATE WED
NIGHT AND THURSDAY. THE MAIN CHALLENGE WILL BE HOW MUCH THE DRY
EASTERLY LOW LEVEL FLOW WILL ERODE THE ADVANCING RAIN TO THE
NORTH. THE NAM IS THE MOST CONSERVATIVE WITH THE RAIN...KEEPING IT
OUT OF OUR NE FORECAST AREA...WHILE THE GFS/EC/GEM DO TAKE IT
THROUGH SHEBOYGAN AND FOND DU LAC BY WEDNESDAY NIGHT. THE MOISTURE
TRANSPORT AND SUPPORT DIMINISHES BY THURSDAY AFTERNOON...SO WE
SHOULD SEE MOST OF THE RAIN END BY LATE AFTERNOON OR EARLIER.

FRIDAY...FORECAST CONFIDENCE IS HIGH.

THIS LOOKS LIKE A DRY AND COOL DAY AS HIGH PRESSURE RETURNS...BUT
THE COOL EAST TO NORTHEAST FLOW DOMINATES.

SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.

ANOTHER SIMILAR MID LEVEL CIRCULATION LIFTS INTO THE AREA FOR THE
WEEKEND...BRINGING CHANCES OF SHOWERS. THE COOL EAST NORTHEAST
FLOW CONTINUES.

AVIATION/00Z TAFS/...

SEVERAL ROUNDS OF NORTH TO SOUTH ORIENTED LINES OF SCATTERED
THUNDERSTORMS ARE EXPECTED TO TRACK THROUGH SOUTHEAST WI LATE THIS
AFTERNOON INTO THE EARLY EVENING. KEEP AN EYE ON RADAR FOR TIMING OF
THUNDERSTORMS. CIGS AND VSBY RESTRICTIONS ARE ONLY EXPECTED WITHIN
THE STORMS. SOME STORMS COULD PRODUCE LARGE HAIL AND DAMAGING WINDS.

A COLD FRONT WILL SLIDE SOUTH THROUGH SOUTHERN WI LATE TONIGHT.
EXPECT BRISK NORTHERLY WINDS AND A LOW STRATUS DECK...BELOW 1000
FT...INTO SRN WI. LOW CONFIDENCE... BUT THERE COULD BE DRIZZLE WITH
THE LOW CLOUDS AND SOME ASSOCIATED MVFR FOG.

MARINE...

SCATTERED THUNDERSTORMS EXPECTED THIS AFTERNOON AND EARLY EVENING.
SOME COULD BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS.

WINDS WILL SHIFT TO THE NORTHWEST TO NORTH LATER THIS EVENING AS LOW
PRESSURE PASSES BY. LOOK FOR THOSE WINDS TO TURN STRONG AND GUSTY
LATER TONIGHT...SHIFTING TO THE NORTHEAST BY TUE AFTN.  WAVES WILL
BUILD TO 3 TO 5 FEET TUE AM. THE HIGHER WINDS AND WAVES WILL
CONTINUE THROUGH WED SOUTH OF NORTH POINT LIGHTHOUSE WHILE FALLING
BELOW SCA CRITERIA LATE TUE EVE NORTH OF NORTH POINT LIGHTHOUSE.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 7 AM TUESDAY TO 1 AM CDT WEDNESDAY FOR
     LMZ645-646.

     SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM CDT TUESDAY FOR LMZ643-
     644.

&&

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.