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000
FXUS63 KMKX 221918 AAB
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
218 PM CDT TUE JUL 22 2014

.UPDATE...

SPC TRIMMED THE SLIGHT RISK A LITTLE FURTHER SOUTHEAST. MESOSCALE
MODELS CONTINUE TO KEEP THE AREA CAPPED UNTIL THE FRONT GETS INTO
FAR SOUTHEAST WI OR EVEN NORTHEAST IL LATE THIS AFTERNOON BETWEEN
22Z AND 00Z. SPC MESOANALYSIS RAP IS SHOWING ERODING CIN ALONG THE
FRONT IN CENTRAL WI...SO I WILL KEEP THE SLIGHT CHANCE ALONG THE
FRONT AS IT MOVES SOUTHEAST THROUGH THE MKX FORECAST AREA. WE
CANNOT RULE STORM DEVELOPMENT GIVEN THE STRONG SURFACE CONVERGENCE...
HIGH DEWPOINTS AND SIGNS OF SLIGHT UPSTREAM COOLING AT 700-850MB.

&&

.AVIATION/18Z TAFS/...

A COLD FRONT MOVING SOUTHEAST THROUGH SOUTHERN WI WILL BRING A
CHANCE OF SHOWERS AND THUNDERSTORMS ALONG IT LATE THIS AFTERNOON.
THE CHANCE WILL INCREASE AS THE FRONT GETS INTO FAR SOUTHEAST
WISCONSIN AROUND 6 PM...ESPECIALLY KENOSHA AND THEN SOUTHWARD INTO
NORTHEAST IL.

KEPT VICINITY THUNDERSTORMS IN TAFS FOR LATE AFTERNOON/EVENING...
WHICH WILL BRING MVFR CIGS/VSBYS IF/WHEN THEY DEVELOP. WINDS WILL
BECOME NORTHWEST BEHIND THE FRONT... THEN NORTH TO NORTHEAST
OVERNIGHT. EXPECT A PERIOD OF BROKEN VFR CUMULUS CLOUDS WED MIDDAY
ON STEADY NORTHERLY WINDS.

&&

.PREV DISCUSSION... /ISSUED 1101 AM CDT TUE JUL 22 2014/

UPDATE...

THE COLD FRONT WITH A WIND SHIFT AND A CHANCE FOR SHOWERS AND
THUNDERSTORMS TRACKING SOUTHEAST THROUGH WI TODAY IS EXPECTED TO
REACH MADISON AROUND 4 PM AND MILWAUKEE AROUND 6 PM. THESE TIMES ARE
BASED ON THE HRRR AND THE WRF-ARW MODELS. THERE IS GENERALLY GOOD
MODEL AGREEMENT...GIVE OR TAKE 2 HOURS. THE NAM CAME IN SLOWER WITH
THE FRONTAL PASSAGE AND THE RAP IS A LITTLE FASTER.

DEWPOINT TEMPS ARE POOLING IN THE LOWER 70S JUST AHEAD OF THE COLD
FRONT. VISIBLE SATELLITE IS ALSO SHOWING CLEARER SKIES IN THIS AREA.
THIS WILL ALLOW TEMPS TO HEAT UP TO OUR EXPECTED MAX AROUND 90. HEAT
INDEX VALUES ARE STILL EXPECTED IN THE MID 90S.

WE WILL BE CAPPED UNTIL THE FRONT GETS INTO SOUTHEAST WI. THE HRRR
IS CONSISTENT IN PRODUCING CONVECTION OVER SOUTHEAST WI JUST AFTER
IT PASSES THROUGH MADISON. WE WILL WATCH TO SEE IF THIS TREND
CONTINUES WITH THE MODEL.  SEE THE PREVIOUS FORECAST DISCUSSION FOR
MORE DETAILS ABOUT THE AFTERNOON CONVECTION.

PREV DISCUSSION... /ISSUED 506 AM CDT TUE JUL 22 2014/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

RADAR RETURNS OVER WEST CENTRAL AND SW WISCONSIN ON LEADING EDGE OF
850 MB WARM ADVECTION...IN REGION OF DECENT CONVERGENCE. HOWEVER NO
GROUND TRUTH AS PRECIP IS DEVELOPING ABOVE DRY...WARM LAYER BETWEEN
750MB AND 650 MB RESULTING IN VIRGA ONLY MAKING IT DOWN TO AROUND 5K
FT ABOVE THE GROUND.

THIS CAPPING INVERSION WILL BE PROBLEMATIC DURING THE DAY AS WARM
ADVECTION CONTINUES TO STRENGTHEN THE CAP AHEAD OF THE COLD FRONT.
CONSENSUS SFC-BASED CAPE INCREASES TO BETWEEN 2500 AND 3000 J/KG BUT
CIN REMAINS IN THE 150 TO 200 J/KG RANGE. NAM DOES SHOW AN ERODING
CAP TOWARDS THE 22Z-00Z TIME FRAME...BUT IT HAS DEW POINTS
APPROACHING 80F AND SB-CAPE APPROACHING 5000 J/KG. FOLLOWING LOWER
CONSENSUS TEMPS/DEW POINTS TRENDS TOWARD THE MORE CAPPED SOLUTION.

BULK SHEAR OF 25 TO 30 KTS ACCOMPANIES MEAGER 500 MB HEIGHT
FALLS/MID-LEVEL COOLING AS SRN EDGE OF SHORT WAVE TROUGH PASSES
THROUGH LEADS TO THE POTENTIAL FOR SOME ISOLATED/SCATTERED SEVERE
STORMS IF CAP IS BROKEN AS FRONT PASSES THROUGH.  WILL LIMIT POPS TO
MID-HIGH CHANCE CATEGORY LATE THIS AFTERNOON AND EVENING.

FORECAST TEMPERATURES IN THE UPPER 80S TO LOW 90S WITH LOW-MID 70S
DEW POINTS KEEP APPARENT TEMPERATURES BELOW HEAT ADVISORY HEADLINES
EXCEPT FOR A SMALL PORTION OF THE WESTERN CWA AROUND LONE ROCK. NOT
CONFIDENT IN HIGHS REACHING THE FORECAST IF CLOUDS REMAIN THICKER
THAN EXPECTED AND  TOO SMALL AN AREA FOR A HEADLINE. WILL CONTINUE
ISSUANCE OF SPS HIGHLIGHTING THE NEAR-ADVISORY WARMTH.

PRECIP CHANCES EXIT WITH FRONT LATE THIS EVENING WITH COOLER AND
DRIER AIR MOVING IN. TEMPERATURES DOWN INTO THE LOWER 60S AND DEW
POINTS IN THE MID TO UPPER 50S BY WEDNESDAY MORNING.

WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE...HIGH

HIGH PRESSURE IS EXPECTED TO BRING DRY WEATHER AND AMPLE SUNSHINE
WEDNESDAY AND THURSDAY. IT SHOULD BE A COUPLE OF VERY PLEASANT
DAYS WITH HIGHS IN THE 70S MOST PLACES. THREW IN SOME LOW POPS
SOUTHWEST THURSDAY NIGHT...AS THE HIGH HEADS EAST AND WARM
ADVECTION MAY KICK OFF A FEW STORMS.

FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM

A SERIES OF SHORTWAVES ARE EXPECTED TO BRING SHOWER/STORM CHANCES
TO SOUTHERN WISCONSIN AT TIMES FRIDAY THROUGH THE WEEKEND. MODELS
STILL HAVE SOME DETAILS TO WORK OUT...SO LEFT CHANCE POPS THROUGH
THE WEEKEND. LOOKS LIKE TEMPS WILL BE NEAR NORMAL THROUGH SUNDAY.

IT LOOKS LIKE THERE WILL BE LESS AVAILABLE MOISTURE EARLY NEXT
WEEK...BUT STILL WENT WITH SOME LOW POPS MONDAY AS MODELS ARE
ADVERTISING A WEAK WAVE. TEMPS SHOULD BE A COUPLE DEGREES COOLER
AS WELL.

AVIATION/12Z TAFS/...

EXPECT VFR CONDITIONS THROUGH THE FORECAST. CURRENT BAND OF HIGH-
BASED PRECIPITATION ON RADAR OVER SOUTHERN WISCONSIN STRUGGLING
TO REACH THE GROUND...THOUGH A FEW SPOTS HAVE REPORTED VERY LIGHT
RAIN/SPRINKLES WITH ONLY TRACE AMOUNTS. BEST CHANCE FOR SHOWERS
AND STORMS WILL BE ALONG COLD FRONT...BUT WILL HAVE TO BREAK
THROUGH WARM MID-LEVEL CAP. WILL KEEP VICINITY THUNDERSTORMS IN
TAFS FOR LATE AFTERNOON/EVENING...WHICH WILL BRING MVFR CIGS/VSBYS
IF/WHEN THEY DEVELOP. GUSTY SOUTH TO SOUTHWEST WINDS AHEAD OF
FRONT WILL LOWER AND TURN NORTH TO NORTHEAST BEHIND FRONT TONIGHT.

MARINE...HAVE LEFT SMALL CRAFT ADVISORY HOURS FROM PREVIOUS
FORECAST. EXPECT SOUTH TO SOUTHWEST WIND GUSTS TO REACH CRITERIA
MID-MORNING AND CONTINUE INTO LATE THIS AFTERNOON BEFORE LOWERING
AS COLD FRONT/SURFACE TROUGH MOVES THROUGH. WAVES WILL BE SLOWER
TO LOWER...SO 9 PM END TIME IS LOOKING GOOD. WINDS AND WAVES WILL
RISE ON WEDNESDAY AS HIGH PRESSURE BUILDS IN

BEACHES...SOUTH TO SOUTHWEST WINDS WILL GUST TO BETWEEN 20 AND 25
KNOTS TODAY. WHILE SOUTHERN ZONES WILL ONLY SEE WAVES BUILD TO 1
TO 3 FEET AT MOST ALONG THE BEACHES...THE NORTHERN 2 ZONES MAY SEE
3 TO 5 FOOT WAVES...ESPECIALLY AT SOUTH-FACING BEACHES. THIS
PLACES SHEBOYGAN AND OZAUKEE COUNTY BEACHES IN A MODERATE RISK OF
SWIMMING HAZARDS.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR LMZ643>646.

&&

$$

UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...REM
WEDNESDAY THROUGH MONDAY...DDV