AP-WI--MKE-WI SO Central Area Forecast Discussion, WI

000

FXUS63 KMKX 151521

AFDMKX

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI

1021 AM CDT WED JUL 15 2015

.AVIATION/18Z TAFS/...VFR CONDITIONS TODAY INTO MUCH OF THE NIGHT

WITH DRY/STABLE INFLUENCE OF SURFACE HIGH. EXPECT AN INCREASE IN

MID LEVEL CLOUDS AS THE NIGHT WEARS ON WITH LATEST RAP SOUNDINGS

SHOW LOW LEVELS REMAINING QUITE DRY. IMPRESSIVE LLJ TAKES AIM AT

SRN WI FOR THURSDAY WITH DECENT THERMAL/MOIST ADVECTION EXPECTED.

SO HIGH POPS LOOK GOOD. SREF MVFR CIG PROBS SHOW GREATEST

LIKELIHOOD OF MVFR/IFR CONDITIONS ACRS NRN WI ON THURSDAY.

PC

&&

.PREV DISCUSSION... /ISSUED 359 AM CDT WED JUL 15 2015/

TODAY...FORECAST CONFIDENCE IS HIGH.

KEEPING EYE ON LOW CLOUDS MOVING WWD ACROSS LAKE FROM LOWER MI.

APPEARS DECREASING TREND SHOWING UP ON LATEST IR IMAGERY. LOW

CLOUDS NOT INDUCED BY LAKE EFFECT DUE TO MINIMAL DELTA T

DIFFERENCE. CLOUDS ALSO RUNNING INTO DRIER AIR AND SUBSIDENCE OVER

SRN WI. AFTER PATCHY EARLY MORNING CLOUDS IN THE SOUTHEAST...STILL

EXPECTING A VERY PLEASANT DAY UNDER LOTS OF SUNSHINE WITH SOME

PASSING MID TO HIGH CLOUDS LATER THIS MRNG AND AFTN.

NORTHEAST BREEZES WL CONTRIBUTE TO TEMPERATURES REMAINING BELOW

NORMAL TODAY. WARMEST TEMPS IN FAR WEST WHERE KLNR WL MOST LIKELY

CRACK 80.

TONIGHT...FORECAST CONFIDENCE IS HIGH.

A QUIET NIGHT IS EXPECTED MOST AREAS AS SHORT WAVE RIDGING SLIDES

OFF TO THE EAST. DRY AIR AND LIGHT WINDS WILL ALLOW TEMPERATURES

TO FALL RAPIDLY DURING THE EVENING. HOWEVER EXPECT INCREASING MID

TO HIGH CLOUDS LATER IN THE EVENING AND OVERNIGHT AS UPSTREAM LOW

LEVEL JET FOCUSES ON IA/MN. SOUTHWEST WI GETS CLIPPED BY

INCREASING MID LEVEL MOISTURE AND SURGE OF 700MB WARM AIR

ADVECTION. MAY BE JUST ENOUGH MID LEVEL INSTABILITY FOR ISOLD

-SHRA/-TSRA TO DEVELOP LATE TNGT ACROSS FAR WRN CWA WITH BULK OF

PRECIPITATION OCCURRING ON THURSDAY.

SHORT TERM...THURSDAY THROUGH FRIDAY NIGHT...FORECAST CONFIDENCE

IS MEDIUM.

MODELS ARE STILL SHOWING SOME VARIATION IN TIMING AND PLACEMENT OF

FEATURES FOR THURSDAY INTO THURSDAY NIGHT. THE NAM AND CANADIAN

MODELS CONTINUE TO BRING WEAK LOW PRESSURE AND A WARM FRONT

NORTHEASTWARD TOWARD AND ACROSS CENTRAL/NORTHEAST WISCONSIN

DURING THIS PERIOD. THE GFS HAS TRENDED FURTHER NORTHWARD WITH

THESE FEATURES...SIMILAR TO THE NAM/CANADIAN. THE ECMWF CONTINUES

TO BE THE FURTHEST SOUTH WITH THESE FEATURES...NORTHEASTWARD INTO

AND ACROSS SOUTHERN WISCONSIN.

ALL MODELS SHOW A GOOD AMOUNT OF FOCUSED WARM AIR ADVECTION ACROSS

THE AREA THURSDAY INTO THURSDAY NIGHT. THE BEST FRONTOGENESIS

RESPONSE FIELDS REMAIN NORTH/NORTHWEST OF THE AREA...ALONG WITH

THE NOSE OF THE SOUTH SOUTHWESTERLY LOW LEVEL JET. THE MAIN 500 MB

VORTICITY MAXIMUM MOVES THROUGH THE REGION ON THURSDAY...FOCUSING

ON NORTHERN WISCONSIN...EXCEPT THE ECMWF WHICH BRINGS IT THROUGH

SOUTHERN WISCONSIN.

CONTINUED TREND OF BRINGING LIKELY POPS EASTWARD INTO THE AREA

THURSDAY...LINGERING THURSDAY NIGHT. SPC EXPANDED THE MARGINAL

RISK FOR SEVERE STORMS INTO SOUTH CENTRAL WISCONSIN. THERE IS

ENOUGH ELEVATED CAPE LATER THURSDAY INTO THURSDAY NIGHT WITH

MARGINAL DEEP LAYER SHEAR THAT WOULD SUPPORT ISOLATED SEVERE

HAIL. ECMWF HAS MUCH LOWER CAPE VALUES THAN NAM/GFS...SO WENT

BETWEEN THESE FOR CAPE ESTIMATES. HIGH PRECIPITABLE WATER VALUES

AS WELL...SO SOME HEAVY RAINFALL COULD OCCUR.

KEPT CHANCE POPS FOR SHOWERS AND STORMS FRIDAY AND FRIDAY NIGHT

ACROSS THE AREA...AS SURFACE TROUGH/STATIONARY FRONT LINGERS WEST

TO EAST. NAM/ECMWF SHOWING A POSSIBLE MCS TRYING TO MOVE ALONG IT

TOWARD THE AREA FRIDAY NIGHT. THE OTHER MODELS HINT AT QPF ALONG

THE BOUNDARY AT VARIOUS TIMES DURING THIS PERIOD.

AGAIN...WENT BETWEEN HIGH CAPES ON NAM/GFS AND LOWER VALUES ON

ECMWF DURING THIS TIME. DEEP LAYER SHEAR IS MODEST AT BEST...WITH

DECENT PRECIPITABLE WATER VALUES. BEST SHOT AT ANY SEVERE WEATHER

WOULD BE WITH MCS MOVING TOWARD THE AREA LATER FRIDAY NIGHT.

VERY WARM AND HUMID DAY IS EXPECTED FRIDAY...WITH SOUTHWEST WINDS

BRINGING MID TO UPPER 80S ACROSS THE AREA. DEW POINTS SHOULD RISE

INTO THE UPPER 60S TO LOWER 70S AS WELL.

LONG TERM...SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE IS

MEDIUM.

GFS/ECMWF CONTINUE TO SHOW SOME DIFFERENCES WITH TIMING AND

PLACEMENT OF FEATURES DURING THIS PERIOD. ECMWF TRIES TO BRING

POSSIBLE WEAKENING MCS THROUGH THE AREA SATURDAY MORNING...KEEPING

BOUNDARY NEARBY IN THE AFTERNOON. IT BRINGS A COLD FRONT SOUTHEAST

THROUGH THE AREA SUNDAY WITH DECENT QPF VALUES.

THE GFS HAS THE BOUNDARY FURTHER NORTH...WITH THE COLD FRONT

SLIDING THROUGH MAINLY SUNDAY NIGHT WITH GOOD QPF VALUES.

CONTINUED POPS FOR SHOWERS AND THUNDERSTORMS SATURDAY INTO SUNDAY

NIGHT. MODIFIED CAPES AND MODEST AT BEST DEEP LAYER SHEAR SUGGEST

RELATIVELY LOW SEVERE RISK AT THIS TIME.

VERY WARM AND HUMID CONDITIONS CONTINUE SATURDAY AND SUNDAY...THOUGH

LAKE BREEZE SATURDAY SHOULD COOL THINGS DOWN NEAR THE LAKE. HEAT

INDEX VALUES MAY REACH THE MID 90S DURING THIS TIME INLAND.

THERE MAY BE A LULL IN ANY PRECIPITATION ACTIVITY MONDAY INTO

TUESDAY...WITH COOLER AND DRIER AIR WORKING INTO THE REGION. KEPT

CONSENSUS BLEND OF POPS AND TEMPERATURES FOR THIS PERIOD...BUT MAY

HAVE TO GO DRIER IN LATER FORECASTS IF THIS TREND PERSISTS.

AVIATION/12Z TAFS/...

WEAK LOW LEVEL CONVERGENCE OVER SRN LOWER MI AND LAKE MI CARRYING

SOME STRATUS INTO PORTIONS OF THE WI LAKESHORE EARLY THIS MORNING.

UNFORTUNATELY...PATCHY HIGH CLOUDS CURRENTLY OBSCURING TRENDS OVER

PAST HOUR OR SO...BUT SLIGHT DECREASING TREND NOTED IN LAST

SEVERAL 11-3.9 MICRON IMAGES.

STILL...LATEST IMAGE SHOWS LOW CLOUDS KNOCKING ON DOORSTEP OF

KMKE AND KENW SO INTRODUCED IN LATEST UPDATE. WOULD EXPECT THESE

LOW CLOUDS WOULD THIN RAPIDLY EARLY THIS MORNING AS DRIER AIR AND

BUILDING SUBSIDENCE ERODE LOW CLOUDS. OTRW A VFR PERIOD WITH

THICKENING CLOUDS LATER TONIGHT DUE TO UPSTREAM SURGE OF LOW LEVEL

MOISTURE AND WARM AIR.

MARINE...

WINDS REMAINING GUSTY ACROSS SOUTHERN MARINE ZONES EARLY THIS

MORNING. STATIONARY VESSEL IN RACINE HARBOR REPORTING SUSTAINED NE

WINDS OF 13KTS WHILE FARTHER SOUTH...NE WINDS STILL GUSTING TO

26KTS AT KNSW3. FARTHER NORTH...WEAKENING PRESSURE GRADIENT AND

SURGE OF COLD AIR HAS ALLOWED WINDS TO SUBSIDE TO MOSTLY 10 TO

18KTS.

THIS DIMINISHING TREND WI AFFECT SOUTHERN LAKE MI ZONES EARLY

THIS MORNING...BUT EXPECT WINDS TO REMAIN GUSTY ACROSS SRN LAKE MI

ZONE THROUGH 12Z OR SO. HENCE WL EXTEND SMALL CRAFT ADVY IN LMZ646

BUT CANCEL ELSEWHERE.

BEACHES...

WILL LET BEACH HAZARD STATEMENT EXPIRE AT 09Z. WINDS HAVE

DECREASED TO BELOW 15 KNOTS NORTH OF WIND POINT LIGHT OVERNIGHT

DUE TO WEAKENING PRESSURE GRADIENT AND WEAKENING PUSH OF LOW LEVEL

COLD AIR. WINDS REMAIN GUSTY SOUTH OF WIND POINT ACROSS RACINE AND

KENOSHA BEACHES AS WAVE HEIGHTS STILL IN THE 3 TO 5 FT RANGE.

HOWEVER EXPECT WINDS AND WAVES TO SUBSIDE THROUGH 8 AM SO DO NOT

SEE THE NEED TO EXTEND BEACH HAZARD STATEMENT AT THIS TIME. MOST

SWIMMERS WOULD BE HEADING TO THE BEACH LATER THIS MORNING AND AFTN

WHEN WINDS AND WAVES WILL BE SIGNIFICANTLY LOWER.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...

WI...NONE.

LM...NONE.

&&

$$

TODAY/TONIGHT AND AVIATION/MARINE...MBK

THURSDAY THROUGH TUESDAY...WOOD

Delivered by Weather Underground Inc. Wed Jul 15 2015 11:22AM EDT