Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 251551 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1051 AM CDT MON MAY 25 2015

.UPDATE...

LAST AREA OF SHOWERS IS MOVING NORTHEASTWARD INTO THE WESTERN
COUNTIES...DRIVEN BY APPROACHING 500 MB VORTICITY MAXIMUM. THIS
FEATURE WILL MOVE NORTHEASTWARD THROUGH THE AREA BY EARLY THIS
AFTERNOON...WHICH SHOULD TAKE THE LINGERING SHOWER ACTIVITY ALONG
WITH IT.

ALREADY SEEING ROBUST LOW LEVEL MIXING OCCURRING...WITH SOUTHWEST
WIND GUSTS TO AROUND 30 KNOTS IN SPOTS. THE BROKEN TO OVERCAST
CLOUDS WILL MIX OUT TO SCATTERED BY EARLY THIS AFTERNOON...AS THE
MIXING DEEPENS WITH DAYTIME HEATING. RAISED HIGHS INTO THE LOWER
80S IN MOST LOCATIONS...WITH CURRENT TRENDS AND THE DEEP MIXING
EXPECTED THIS AFTERNOON.

KEPT LOWER END POPS FOR LATER THIS AFTERNOON IN THE WESTERN
COUNTIES...THOUGH THIS MAY NEED TO BE TRIMMED BACK OR REMOVED...AS
MAIN UPWARD VERTICAL MOTION FIELDS REMAIN TO THE WEST INTO THIS
EVENING. MESOSCALE MODELS ARE KEEPING MOST SHOWER/STORM ACTIVITY
WEST OF THE AREA INTO THIS EVENING AS WELL.

&&

.AVIATION/18Z TAFS/...

RAIN SHOWERS LINGERING IN THE AREA SHOULD MOVE OUT BY EARLY THIS
AFTERNOON...AS A TROUGH OF LOW PRESSURE MOVES THROUGH. CEILINGS
WILL MIX OUT BY EARLY THIS AFTERNOON...WITH DEEP MIXING OCCURRING
WITH DAYTIME HEATING. GUSTY SOUTHWEST WINDS ARE EXPECTED INTO
EARLY THIS EVENING...WITH GUSTS TO AROUND 25 KNOTS. SOME HIGHER
GUSTS TO 30 KNOTS ARE POSSIBLE AT TIMES.

SOUTHWEST WINDS AT 1500 TO 2000 FEET ABOVE GROUND LEVEL WILL
APPROACH THE 35 TO 40 KNOT RANGE FOR A TIME LATER THIS EVENING
INTO THE OVERNIGHT HOURS. THIS MAY BE ENOUGH FOR A LOW LEVEL WIND
SHEAR MENTION IN THE EASTERN TAF SITES...ALREADY IN TAF AT
MADISON.

SOUTH WINDS WILL WEAKEN SOMEWHAT TONIGHT INTO TUESDAY...AS A
SURFACE TROUGH MOVES TOWARD THE AREA FROM THE WEST. CHANCES FOR
SHOWERS AND STORMS WILL GRADUALLY INCREASE LATER TONIGHT INTO
TUESDAY. VICINITY SHOWERS OR STORMS WORDING WILL LIKELY BE USED
FOR TUESDAY...WITH SOME UNCERTAINTY WITH AREAL COVERAGE AND
TIMING. MVFR CEILINGS/VISIBILITIES ARE POSSIBLE IN ANY HEAVIER
SHOWERS/STORMS.

&&

.MARINE...

SOME FOG IS SEEN ON AREA WEB CAMERAS TOWARD THE OPEN WATERS...AND
SHOULD MIX OUT NEAR THE SHORE WITH THE GUSTY SOUTHWEST WINDS
DEVELOPING. AS THE DEW POINTS REMAIN REASONABLY ABOVE THE WATER
TEMPERATURES...IT MAY LINGER AT TIMES ACROSS THE WATERS FOR MOST
OF THE WEEK. THIS WOULD BE ESPECIALLY TRUE TOWARD THE OPEN
WATERS...MORE UNDER THE INFLUENCE OF THE MARINE INVERSION.

SMALL CRAFT ADVISORY CONTINUES ACROSS THE NEARSHORE WATERS UNTIL
09Z TUESDAY...AS A TIGHT PRESSURE GRADIENT DEVELOPS ACROSS THE
AREA. GUSTY SOUTH WINDS NEAR SHEBOYGAN WILL VEER SOUTHWEST BY
EARLY THIS AFTERNOON...WITH THE GUSTY SOUTHWEST WINDS ALREADY
OCCURRING TO THE SOUTH OF THERE.

GUSTS TO AROUND 25 KNOTS ARE EXPECTED INTO EARLY THIS EVENING
ACROSS THE NEARSHORE WATERS. KENOSHA MAY SEE GUSTS APPROACHING
GALE FORCE LATE THIS MORNING...BUT THINK THESE WILL LOWER INTO THE
25 KNOT RANGE THIS AFTERNOON. HIGHEST WAVES WILL BE TOWARD THE
OPEN WATERS. THE WINDS AND WAVES WILL SUBSIDE BY LATER TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 341 AM CDT MON MAY 25 2015/

SHORT TERM...

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

THE FOCUS THIS MORNING IS ON THE TRACK AND TIMING OF A MID LEVEL
SHORT WAVE TROF AXIS CURRENTLY STRETCHED FROM NE KS INTO NW MO. THIS
SHOULD GENERALLY MARK THE END OR SIGNIFICANT DIMINISHMENT OF THE
PRECIP AS THAT AXIS MOVES THROUGH SRN WISCONSIN THIS MORNING.
CURRENT TIMING HAS IT ALONG THE WI/IL BORDER BY 15Z AND NORTH OF OUR
CWA BORDER BY AROUND 18Z.  AN ASSOCIATED SURFACE LOW/TROF WILL
PRECEDE THE UPPER SYSTEM BY A FEW HOURS AND WILL TRACK ACROSS OUR
WRN FORECAST AREA. THE ENHANCED FORCING/FRONTOGENESIS WITH THIS
FEATURE WILL BRING THE BETTER PRECIP AMOUNTS AND PROBABILITIES WEST
OF MADISON THIS MORNING.

WE SHOULD SEE SOME CLEARING THIS AFTERNOON...ESPECIALLY SOUTHEAST...
IN THE SUBSIDENCE BEHIND THE MID LEVEL TROF AND WITH 925MB TEMPS IN
THE 17-20C RANGE...WE SHOULD SEE SOME PLACES TOP 80F FOR HIGHS.  THE
AFTERNOON SHOULD GENERALLY BE DRY WITH THE PRECIP CHANCES RETURNING
TONIGHT AS ANOTHER TROF APPROACHES FROM THE SOUTHWEST. STRONGER
CONVECTION IS EXPECTED ACROSS IOWA LATE THIS AFTERNOON AND EVENING
AND SOME OF THAT ACTIVITY COULD DRIFT INTO OUR WESTERN CWA LATER IN
THE EVENING AND AFTER MIDNIGHT. SUPPORT FOR THE STRONG STUFF SHOULD
GENERALLY BE LACKING ONCE THEY GET INTO WISCONSIN HOWEVER.

TUESDAY THROUGH WEDNESDAY... FORECAST CONFIDENCE MEDIUM.

A POTENT 500MB SHORTWAVE TROUGH WILL MOVE THROUGH THE UPPER MIDWEST
ON TUESDAY... COINCIDENT WITH THE RIGHT ENTRANCE REGION OF AN UPPER
JET AND A SURFACE TROUGH. THE SURFACE FRONT WILL BE HUNG UP OVER
CENTRAL WI... SO THE WARMTH AND MOISTURE WILL REMAIN IN PLACE OVER
SOUTHEAST WI. MODERATE SHEAR AND STRENGTH OF UPPER LEVEL FORCING MAY
BE ENOUGH TO PRODUCE A FEW STRONGER THUNDERSTORMS. THE LIMITING
FACTOR IS THE AMOUNT OF CAPE DUE TO THE WEAK MID LEVEL LAPSE RATES.
THE NAM HAS THE HIGHEST CAPE OF THE MODELS.  THUS... SPC KEPT THE
SOUTHEAST MKX FORECAST AREA IN THE MARGINAL RISK FOR SEVERE.

CLOUDS AND PRECIP WILL LIMIT THE HEATING ON TUESDAY... BUT HIGHS
SHOULD STILL BE ABLE TO GET INTO THE MID 70S. THE WEAK PRESSURE
GRADIENT WILL LIKELY ALLOW FOR A LAKE BREEZE DURING THE AFTERNOON.

SHOWER AND THUNDERSTORM CHANCES WILL DIMINISH THROUGH THE NIGHT AS
THE SURFACE AND UPPER TROUGHS MOVE OUT OF THE AREA. CLOUDS WILL BE
SLOW TO CLEAR... SO LOWS WILL REMAIN MODERATED IN THE UPPER 50S.

MODELS ARE TRENDING SLOWER WITH GETTING THAT 500MB TROUGH OUT OF THE
AREA. THUS... THE SMALL CHANCE FOR SHOWERS OR MAYBE A THUNDERSTORM
WILL LINGER THROUGH THE DAY WEDNESDAY.

LONG TERM...

WEDNESDAY NIGHT THROUGH THURSDAY EVENING... FORECAST CONFIDENCE
MEDIUM.

THIS TIME PERIOD WILL FEATURE QUIET WEATHER WITH A BRIEF PERIOD OF
UPPER AND SURFACE RIDGING TO ENJOY. TEMPS WILL BE ABOVE SEASONAL
NORMAL IN THE UPPER 70S TO AROUND 80 INLAND FROM LAKE MICHIGAN.

FRIDAY THROUGH SATURDAY NIGHT... FORECAST CONFIDENCE MEDIUM.

ANOTHER UPPER LEVEL TROUGH WILL SET UP OVER THE WEST HALF OF THE
COUNTRY AND SEND ENERGY UP THROUGH WI ALONG A SURFACE TROUGH/
BAROCLINIC ZONE. THAT SURFACE TROUGH WILL SLIDE SOUTH THROUGH THE
PERIOD. THIS WILL LEAD TO MORE CONTINUOUS CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS SOUTHERN WI LATE THIS WEEK.

SUNDAY AND MONDAY... FORECAST CONFIDENCE LOW.

BY SUNDAY... THE ECMWF HAS THIS FRONT SOUTH OF THE WI/IL BORDER
WHILE THE GFS BRINGS IT BACK UP INTO WI DUE TO A MORE NORTHWARD
PLACEMENT OF A CLOSED UPPER LOW OVER THE PLAINS. THEREFORE... THE
ECMWF KEEPS SOUTHERN WI DRY AND THE GFS HAS SEVERAL ROUNDS OF
PRECIP IN THE FORECAST.

AVIATION/12Z TAFS/...

LOOK FOR CIGS IN THE 1500-3000FT RANGE THROUGH ABOUT 15-16Z THIS
MORNING. ALTHOUGH KMSN WILL BE RIGHT ALONG THE LINE WHERE SOME IFR
CIGS BELOW 1KFT ARE POSSIBLE AT TIMES.  A COMBINATION MID LEVEL
SHORT WAVE AND SURFACE LOW WILL BE LIFTING NORTH ACROSS SOUTHERN
WISCONSIN EARLY THIS MORNING...BRINGING SHOWERS TO MUCH OF THE AREA.
THE HEAVIEST RAINFALL WOULD BE FROM MADISON WEST INTO IOWA AND
MINNESOTA...CLOSER TO THE SURFACE LOW TRACK.  WINDS WILL SHIFT TO
SOUTHWEST IN THE WAKE OF THE PASSING LOW AND THAT SHOULD SIGNAL
LIFTING CIGS THAT MAY EVEN SCATTER OUT THIS AFTERNOON. THE TAF SITES
SHOULD ALL BE VFR BY 16Z. THE AFTERNOON IS LOOKING DRY AND THAT WILL
LIKELY CONTINUE INTO THE EARLY EVENING. SHOWERS AND POSSIBLE
THUNDERSTORM CHANCES RETURN LATER THIS EVENING AND INTO THE
OVERNIGHT HOURS. WE COULD SEE MVFR CIGS RETURN BY 12Z TUE.

MARINE...

STRONG SOUTH TO SOUTHWEST WINDS WILL BRING SMALL CRAFT ADVISORY
CONDITIONS THROUGH TONIGHT. THE HIGHEST WAVES WILL BE OUT TOWARD
OPEN WATER.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CDT TUESDAY FOR LMZ643>646.

&&

$$

UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
TUESDAY THROUGH SUNDAY...MRC



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