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000
FXUS63 KMKX 180820
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
320 AM CDT TUE JUN 18 2013

.TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

CANADIAN HIGH PRESSURE CONTINUES TO DRIFT SOUTH ACROSS THE AREA
TODAY. EXPECT MUCH COOLER NORTHEAST WINDS COMPARED TO THE HEAT OF
YESTERDAY. ONLY CONCERN TODAY IS RELATED TO THE STRONG MID LEVEL
SHORT WAVE TROF TRACKING FROM THE MN/IA BORDER EARLY THIS
MORNING...SOUTHEAST TO THE IL/IN STATE LINE JUST SOUTH OF CHICAGO
BY EARLY THIS EVENING.

A RESPECTABLE CLUSTER OF THUNDERSTORMS IS LOCATED RIGHT UNDER THE
COLD CORE OF THIS UPPER SYSTEM AND WITHIN A DECENT LEFT EXIT
REGION OF THE UPPER JET AT 2AM THIS MORNING. EXTRAPOLATING THIS
ACTIVITY STILL BRINGS A THREAT OF SOME STORMS TO THE FAR SOUTHWEST
PORTION OF THE FORECAST AREA...MAINLY SOUTHWEST OF MADISON. THE
NCEP 4KM WRF-NMM...HIRES ARW...NAM AND TO SOME DEGREE THE GEM
REGIONAL AND ECMWF CLIP THE FAR SOUTHWEST WITH SOME QPF. IT LOOKS
LIKE MOST OF THIS SHOULD EXIT TO THE SOUTH BY EARLY AFTERNOON.

OTHERWISE...THE REST OF THE FORECAST AREA WILL BE QUIET AND COOLER
WITH NORTHEAST WINDS. MORE SUN NORTH OF MILWAUKEE AND MADISON THAN
TO THE SOUTH. QUIET AND CONTINUED COOL TONIGHT WITH HIGH PRESSURE
SOLIDLY OVERHEAD.

.WEDNESDAY THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM
TO HIGH.

SHORT TERM MODELS CONTINUE TO INDICATE HIGH PRESSURE AT THE
SURFACE OVER LAKE MICHIGAN SLIDING EAST WEDNESDAY INTO THURSDAY.
500MB VORTICITY MAXIMUM SLIDES EAST ACROSS THE AREA LATE WEDNESDAY
NIGHT INTO THURSDAY. AREA FORECAST SOUNDINGS FROM NAM/GFS WERE
SHOWING SOME MID LEVEL MOISTURE AND WEAK CAPE WITH THIS
FEATURE...BUT THE REST OF THE SOUNDING WAS DRY. GRADUAL WARM AIR
ADVECTION DOES OCCUR IN THE LOW LEVELS. AREA OF QPF CLIPS THE FAR
SOUTHWEST COUNTIES THURSDAY AFTERNOON ON NAM/GFS...WITH THE ECMWF
DRY.

WILL KEEP THIS PERIOD DRY FOR NOW...THOUGH MAY HAVE TO ADD LOW
POPS FOR THURSDAY IN LATER FORECASTS IF BETTER MOISTURE AND UPWARD
VERTICAL MOTION ARE EVIDENT. TEMPERATURES WILL SLOWLY WARM DURING
THIS TIME...TO AROUND SEASONAL NORMAL VALUES. ONSHORE WINDS WILL
KEEP LAKESHORE AREAS COOLER.

LOW LEVEL WARM AIR ADVECTION CONTINUES THURSDAY NIGHT ACROSS THE
AREA...WITH THE LOW LEVEL JET REMAINING FOCUSED NORTH TO NORTHEAST
OF THE AREA. MORE MOISTURE IN THE LOW LEVELS DEVELOPS...AND LEADS
TO MORE ELEVATED INSTABILITY. THE NAM SHOWS QUITE A BIT MORE
ELEVATED CAPE THAN THE GFS. SHORT TERM MODELS SHOW BEST QPF TO THE
NORTH OF THE AREA NEAR THE WARM FRONT...WITH THE NAM THE MOST
AGGRESSIVE WITH BRINGING QPF INTO THE SOUTH CENTRAL WISCONSIN
AREA. CONTINUED LOW END POPS FOR THURSDAY NIGHT ACROSS THE SOUTH
CENTRAL COUNTIES FOR NOW.

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

GFS/ECMWF SHOW DIFFERENCES WITH FEATURES DURING THIS PERIOD ACROSS
THE REGION. GFS SHOWS THE WARM FRONT WELL NORTH OF THE AREA DURING
MOST OF THIS PERIOD...WITH SOUTHERN WISCONSIN FIRMLY IN THE WARM
SECTOR AIRMASS. SOUTHWEST FLOW AT 500MB TAKES HOLD OVER THE REGION
DURING THIS TIME...WITH VARIOUS VORTICITY MAXIMA PASSING THROUGH.
MOST OF THE QPF ON THE GFS IS FOCUSED NEAR THE WARM FRONT OVER
NORTHERN WISCONSIN.

THE ECMWF IS FURTHER SOUTH WITH THE WARM FRONT...KEEPING IT
STRETCHED ACROSS THE REGION FRIDAY INTO SATURDAY. IT THEN SHIFTS
NORTHWARD SATURDAY NIGHT INTO SUNDAY. 500MB FLOW BECOMES WEST
SOUTHWESTERLY...WITH VARIOUS VORTICITY MAXIMA MOVING THROUGH. QPF
SHIFTS THROUGH THE AREA PERIODICALLY FRIDAY INTO MONDAY.

GFS FORECAST SOUNDINGS ARE SHOWING A LOT OF MEAN LAYER CAPE DURING
THIS TIME...THOUGH AIRMASS IS CAPPED MAINLY BEYOND FRIDAY. STILL A
FAIR AMOUNT OF MEAN LAYER CAPE AFTER ADJUSTING MODEL DEW POINTS
DOWNWARD SOMEWHAT. DEEP LAYER SHEAR IS MODEST. ALSO SEEING FAIRLY
HIGH PRECIPITABLE WATER VALUES AT TIMES.

FOR NOW...WILL USE CONSENSUS POPS AND TEMPERATURES FOR THIS
PERIOD. IT CERTAINLY LOOKS LIKE A WARMER AND MORE HUMID AIRMASS
WILL MOVE INTO THE REGION.

&&

.AVIATION/12Z TAFS/...VFR CONDITIONS EXPECTED THROUGH THE PERIOD
AS CANADIAN HIGH SINKS SOUTH ACROSS THE AREA.

&&

.MARINE...NORTHEAST WINDS AND WAVES WILL BE CLOSE TO SMALL CRAFT
ADVISORY CRITERIA EARLY THIS MORNING. WILL NOT ISSUE A SMALL CRAFT
ADVISORY AT THIS TIME...BUT SMALL CRAFT SHOULD EXERCISE CAUTION.
WINDS AND WAVES WILL DIMINISH BY THIS AFTERNOON.

&&

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

$$

TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
WEDNESDAY THROUGH MONDAY...WOOD