Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 241428 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
928 AM CDT FRI JUL 24 2015

.UPDATE...

HAVE UPDATED POPS AND SKY COVER THIS MORNING TO ACCOUNT FOR DYING
MCS ABOUT TO ENTER THE WESTERN FORECAST AREA. THE HRRR SEEMS TO
HAVE THE BEST HANDLE ON IT...SO MODELED SHORT TERM FORECAST AFTER
IT. EXPECT THE RAIN TO MOVE INTO THE WEST THIS
MORNING...DIMINISHING AS AT APPROACHES THE SOUTHEAST EARLY THIS
AFTERNOON. SHOULD MID DRY MID/LATE AFTERNOON...EXCEPT FOR A SLIGHT
CHANCE FOR SHOWERS/STORMS NORTHWEST LATE AFTERNOON AS NEXT ROUND
OF CONVECTION TRIES TO DEVELOP.

MAY HAVE TO LOWER HIGH TEMPS A BIT IF EXTENSIVE CIRRUS DECK FROM
CONVECTION HANGS ON WELL INTO THE AFTERNOON.

&&

.AVIATION/18Z TAFS/...

A DYING MCS WILL LIKELY BRING SOME LIGHT TO MODERATE RAIN TO THE
SOUTHWEST HALF OF THE FORECAST AREA THIS MORNING INTO EARLY
AFTERNOON. COULD BE A RUMBLE OR TWO OF THUNDER...BUT THUNDER
CHANCES WILL LIKELY DECREASE OVER THE NEXT FEW HOURS AS THE
COMPLEX WIPES OUT. VFR CONDITIONS SHOULD PERSIST...OTHER THAN SOME
BRIEFLY LOWER VSBYS IN MODERATE RAINFALL.

THERE WILL BE MORE SHOWER/STORM CHANCES THIS EVENING AND OVERNIGHT
AS AN UPPER WAVE AND WEAK SURFACE FRONT DROP THROUGH THE AREA.
LOOKS MAINLY DRY THEN SATURDAY AS HIGH PRESSURE MOVES BACK INTO
THE AREA.

&&

.PREV DISCUSSION... /ISSUED 344 AM CDT FRI JUL 24 2015/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

A 250 MB UPPER LEVEL RIDGE ACROSS WISCONSIN EARLY THIS MORNING
WILL REACH THE EASTERN GREAT LAKES LATE TONIGHT...AS A WEST TO
EAST UPPER LEVEL JET INCREASES TO 105 KNOTS ACROSS WISCONSIN
TONIGHT.

WEAK UPPER LEVEL DIVERGENCE TODAY...THEN INCREASING LATE TONIGHT.
WEAK 700 MB UPWARD MOTION MAINLY THIS AFTERNOON...THEN INCREASING
TO MODERATE UPWARD MOTION TONIGHT.

A 40 KNOT 700 MB JET EXITS THE NORTHERN PLAINS AND
MINNESOTA...REACHING AREAS JUST NORTHWEST AND NORTH OF THE
FORECAST AREA. THE JET DECREASES TO AROUND 35 KNOTS THIS
EVENING...BEFORE DROPPING INTO SOUTHERN WISCONSIN TONIGHT AT
AROUND 30 KNOTS.

700/850 AND SURFACE DEWPOINTS INCREASE THROUGH THE AFTERNOON.
ZERO TO 1 KM MIXED LAYER CAPE INCREASES...BUT THE HIGH CAPE AXIS
IS STILL NORTHWEST OF THE FORECAST AREA EARLY THIS EVENING...WITH
ONLY AROUND 600 JOULES/KG ACROSS SOUTH CENTRAL AND SOUTHEAST
WISCONSIN. BY THE TIME THE SURFACE FRONT ARRIVES OVER SOUTH
CENTRAL WISCONSIN...ZERO TO 1 KM CAPES ARE AROUND 1200
JOULES/KG...AND AROUND 700 JOULES/KG FAR SOUTHEAST TOWARD SUNRISE
SATURDAY.

THE GFS HAS A RATHER STRONG CAP ABOVE 850 MB THAT ONLY WEAKENS
TONIGHT.

MODELS ARE NOT VERY CONSISTENT WITH THE UPSTREAM MINNESOTA
CONVECTION. THE MORE AGGRESSIVE ONES TAKE A WEAKENING AREA OF
SHOWERS/THUNDERSTORMS INTO SOUTH CENTRAL AND PORTIONS OF SOUTHEAST
WISCONSIN TODAY...WHILE THE OTHER WEAKEN THE THUNDERSTORMS
COMPLETELY BEFORE REACHING SOUTH CENTRAL WISCONSIN. THEN THE
CHANCE OF THUNDERSTORMS INCREASE WITH THE COLD FRONT LATER
TONIGHT. FOR NOW WILL GO WITH A COMPROMISE.

SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT...FORECAST CONFIDENCE
IS MEDIUM.

KEPT LOW POPS GOING IN THE FAR SOUTHEAST EARLY IN THE MORNING
SATURDAY...AS COLD FRONT MOVES SOUTHEASTWARD OUT OF THE AREA.
OTHERWISE...MODELS ARE SHOWING HIGH PRESSURE WORKING SOUTHEASTWARD
INTO THE AREA. NAM SOUNDINGS ARE TOO MOIST AND TOO UNSTABLE...SO
FOLLOWED THE MORE REASONABLE GFS SOUNDINGS WITH THE DRIER AIRMASS
FOR SATURDAY INTO SATURDAY EVENING.

THUS...WENT WITH A DRY FORECAST FOR THIS PERIOD. WARM
TEMPERATURES ARE EXPECTED INLAND SATURDAY...PER BLENDED MODEL
GUIDANCE. LAKE BREEZE WILL KEEP LAKESHORE AREAS A BIT COOLER.

THE HIGH SHIFTS OFF TO THE EAST LATER SATURDAY NIGHT AND
SUNDAY NIGHT...AS AN AXIS OF WARM AIR ADVECTION AND A WARM FRONT
APPROACH THE AREA FROM THE WEST. 500 MB VORTICITY MAXIMUM PASSES
THROUGH THE AREA LATER SUNDAY AND EARLY SUNDAY NIGHT.

MODELS ARE IN SOME DISAGREEMENT WITH THE TIMING AND PLACEMENT OF
THESE FEATURES...ESPECIALLY SUNDAY NIGHT. NAM APPEARS OVERDONE
WITH CONVECTIVE FEEDBACK SUNDAY NIGHT ACROSS THE AREA. CONSENSUS
OF GFS/ECMWF/CANADIAN MODELS SUGGEST CONTINUING SLOWLY INCREASING
POPS SATURDAY NIGHT INTO SUNDAY NIGHT FROM WEST TO EAST. ANOTHER
MILD DAY IS EXPECTED INLAND...WITH SOMEWHAT COOLER VALUES NEAR
THE LAKE WITH ONSHORE WINDS.

LONG TERM...MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE IS
MEDIUM.

GFS/ECMWF SHOWING A 500 MB RIDGE SHIFTING EAST ACROSS THE AREA
MONDAY INTO TUESDAY...BEFORE A DEEP 500 MB LOW SHIFTS EASTWARD
ACROSS FAR SOUTH CENTRAL CANADA INTO JAMES BAY WEDNESDAY INTO
THURSDAY. THESE MODELS SHOW A GENERAL WARM AIR ADVECTION REGIME
ACROSS THE REGION MONDAY INTO TUESDAY...BEFORE A COLD FRONT
CROSSES THE REGION LATER TUESDAY NIGHT INTO WEDNESDAY. SOME
DIFFERENCES WITH TIMING AND PLACEMENT OF QPF AND SOME FEATURES
DURING THIS PERIOD.

CONTINUED CONSENSUS BLEND OF MODEL POPS FOR MOST OF THIS
PERIOD...HIGHEST TUESDAY NIGHT INTO WEDNESDAY. DRIER AIR THEN
WORKS INTO THE REGION FOR THURSDAY. MILD TEMPERATURES LOOK TO
CONTINUE FOR MOST OF THIS PERIOD...PER CONSENSUS BLEND OF MODEL
TEMPERATURES.

AVIATION/12Z TAFS/...

LOOKING AT SIMILAR VFR CONDITIONS EARLY THIS MORNING...AS THE
PAST FEW DAYS WITH AREAS OF IFR/LIFR FOG IN THE WISCONSIN RIVER
VALLEY...AND PATCHY GROUND FOG UNTIL JUST AFTER SUNRISE IN LOW
LYING AREAS ELSEWHERE.

MODELS ARE NOT VERY CONSISTENT WITH THE UPSTREAM MINNESOTA
CONVECTION. THE MORE AGGRESSIVE ONES TAKE A WEAKENING AREA OF
SHOWERS/THUNDERSTORMS INTO SOUTH CENTRAL AND PORTIONS OF SOUTHEAST
WISCONSIN TODAY...WHILE THE OTHER WEAKEN THE THUNDERSTORMS
COMPLETELY BEFORE REACHING SOUTH CENTRAL WISCONSIN. THEN THE
CHANCE OF THUNDERSTORMS INCREASE WITH THE COLD FRONT LATER
TONIGHT. FOR NOW WILL GO WITH A COMPROMISE.

EXPECT SHALLOW CUMULUS BELOW THE CAP AT AROUND 4 TO 5 THSD
FT...WITH INCREASING MID/HIGH LEVEL CLOUDS FROM THE UPSTREAM
CONVECTION. THEN MVFR/IFR CONDITIONS IN ANY THUNDERSTORMS TONIGHT.

MARINE...

SOUTHWEST TO SOUTH FLOW INCREASES...WITH A SOUTH TO SOUTHEAST
LAKE BREEZE SETTING IN. WINDS/WAVES SHOULD BE BELOW SMALL CRAFT
CRITERIA. LOOK FOR A CHANCE OF THUNDERSTORMS LATE TONIGHT WITH A
COLD FRONT.

&&

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

$$

UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SATURDAY THROUGH THURSDAY...WOOD


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