Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 011550
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1050 AM CDT MON SEP 1 2014

.AVIATION/18Z TAFS/...LOW PRESSURE LIFTING NORTHEAST FROM LAKE
SUPERIOR WITH TRAILING COLD FRONT INTO NW WI THROUGH CNTRL IA.
AIRMASS QUITE STABLE ATTM AHEAD OF THIS FRONT WITH JUST A COUPLE
BATCHES OF SHRA. CLOUD COVER IS EXTENSIVE AND PRIMARY
SHORTWAVE/SPEED MAX LIFTING NORTHEAST. EXTENSIVE CLOUD COVER
UPSTREAM LIKELY TO KEEP INSTABILITY FROM GETTING OUT OF
HAND....THOUGH SOME HERE AND THERE. SO WHILE FRONT IS YET TO WORK
THROUGH...SVR CONVECTIVE DEVELOPMENT NOT LIKELY. MESO MODELS
CONTINUE TO PULL BACK ON STORM STRENGTH THIS AFTN/EVE...SO AGREE
WITH SPC/S REMOVAL OF SLGT RISK FROM SRN WI. EXPECT MVFR CIGS TO
LINGER INTO THE AFTERNOON WITH THE VERY MOIST LOW LEVELS AHEAD OF
THE COLD FRONT. SOME IMPROVEMENT OF THESE CIGS INTO THIS EVENING
ONCE SFC COLD FRONT WORKS THROUGH AND DRIER NW WINDS KICK IN.
WEAK HIGH BUILDS IN TNGT WITH SFC TROUGH POSSIBLY GENERATING A FEW
SHRA TUE AFTN.

PC

&&

.PREV DISCUSSION... /ISSUED 355 AM CDT MON SEP 1 2014/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

AREA OF RAIN SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST
WISCONSIN...INTO FAR EASTERN IOWA AND FAR NORTHWEST ILLINOIS...HAS
BEEN SLOWLY WEAKENING OVER THE PAST FEW HOURS. THIS WAS BEING DRIVEN
BY 500 MB VORTICITY MAXIMUM MOVING INTO THE AREA...UPPER DIVERGENCE
WITH RIGHT REAR QUADRANT OF 250 MB JET STREAK...ALONG WITH 850 MB
LOW LEVEL JET. SPC MESOANALYSIS PAGE SHOWING A GOOD AMOUNT OF
CONVECTIVE INHIBITION OVER THE AREA...WHICH MAY BE HELPING WEAKEN
CONVECTION.

STILL...THE ABOVE MAIN FEATURES SHOULD CONTINUE TO BRING SOME
SHOWERS ACROSS THE AREA THROUGH THE MIDDLE MORNING HOURS. THIS IS
SUPPORTED BY THE HRRR AND OTHER MESOSCALE MODELS...THOUGH THEY AREA
SOMEWHAT OVERDONE WITH CURRENT PRECIPITATION TRENDS. THUS...WILL
CONTINUE HIGH POPS THROUGH THE MIDDLE MORNING HOURS FOR SHOWERS AND
ISOLATED STORMS.

MAIN ISSUE WILL BE CONVECTIVE TRENDS THIS AFTERNOON AND EVENING WITH
PASSING COLD FRONT AND SEVERE WEATHER POSSIBILITIES. COLD FRONT WILL
PASS EAST THROUGH THE AREA THIS AFTERNOON...EXITING THE SOUTHEAST BY
MIDDLE TO LATE EVENING. SYNOPTIC MODELS VARY A BIT IN THE TIMING OF
THE FRONT. FRONTOGENESIS RESPONSE WITH FRONT IS WEAK AS IT MOVES
THROUGH THE AREA...THOUGH ELONGATED 500 MB VORTICITY MAXIMUM PUSHES
INTO THE AREA FROM THE WEST. WENT WITH CHANCE POPS FOR THIS
AFTERNOON...AND EVENING IN THE SOUTHEAST...AS THERE IS SOME
UNCERTAINTY WITH THE AREAL COVERAGE OF CONVECTION WITH THE FRONT.

IF MORNING PRECIPITATION CAN MOVE OUT AND CLOUDS BREAK UP THIS
AFTERNOON...SHOULD SEE AT LEAST 1000 TO 1500 J/KG OF MEAN LAYER CAPE
AND AROUND 50 KNOTS OR SO OF DEEP LAYER SHEAR. THIS IS CERTAINLY
SUPPORTIVE OF SEVERE CONVECTION...WITH LARGE HAIL AND DAMAGING WINDS
POSSIBLE. SPC HAS MOST OF THE AREA IN A SLIGHT RISK FOR SEVERE
STORMS THIS AFTERNOON AND EARLY THIS EVENING.

DRIER AIR WORKS INTO THE AREA LATER TONIGHT...BRINGING QUIETER
WEATHER. HIGHS TODAY WILL DEPEND ON AMOUNT OF CLOUDS LINGERING FROM
MORNING PRECIPITATION. WENT WITH UPPER 70S TO LOWER 80S FOR NOW.
LOWS TONIGHT SHOULD DROP INTO THE UPPER 50S TO LOWER/MID 60S.

TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...HIGH

IT LOOKS MAINLY DRY TUESDAY AND WEDNESDAY AS SURFACE HIGH PRESSURE
SLIDES THROUGH THE AREA. DID ADD A SLIGHT CHANCE FOR
SHOWERS/STORMS IN THE NORTH TUESDAY...AS MODELS NOW IN DECENT
AGREEMENT WITH A WEAK SHORTWAVE PASSING THROUGH. WARM TEMPS WILL
CONTINUE BOTH DAYS WITH HIGHS NEAR TO A FEW DEGREES ABOVE NORMAL.

WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM

BUMPED POPS UP WEDNESDAY NIGHT...AS MODELS ARE IN PRETTY GOOD
AGREEMENT IN BRINGING STRONG WARM AIR ADVECTION INTO SOUTHERN
WISCONSIN ON THE NOSE OF A 40-50 KT LLJ. LOOKS LIKE A SHORTWAVE
WILL ALSO BE MOVING THROUGH...WHICH SHOULD HELP TO FIRE OFF SOME
SHOWERS/STORMS.

THE PRECIP MAY HANG ON INTO THURSDAY MORNING...WITH MOST MODELS
THEN SHOWING A DRIER AND VERY WARM AFTERNOON IF THE SUN CAN COME
OUT. MODEL 925 MB TEMPS GET UP TO AROUND 25-26C...WHICH WOULD
RESULT IN HIGHS AROUND 90 GIVEN ENOUGH SUN. THROW IN DEWPOINTS IN
THE LOW 70S AND IT COULD END UP BEING AN UNCOMFORTABLE EARLY
SEPTEMBER DAY.

THE COLD FRONT IS EXPECTED TO MOVE THROUGH THURSDAY
NIGHT...BRINGING MORE THUNDERSTORM CHANCES. LINGERED SOME POPS
INTO FRIDAY DUE TO A COUPLE MODELS BEING A BIT SLOWER WITH THE
TIMING OF THE FRONT AND SHORTWAVE. SHOULD SEE HIGH TEMPS BACK DOWN
TO AROUND NORMAL FOR FRIDAY.

SATURDAY AND SUNDAY...FORECAST CONFIDENCE...MEDIUM

IT LOOKS COOLER AND DRY SATURDAY AND SUNDAY AS HIGH PRESSURE
SETTLES INTO THE GREAT LAKES REGION. TEMPERATURES WILL LIKELY BE
A FEW DEGREES BELOW NORMAL IF CURRENT MODEL FORECASTS VERIFY.

AVIATION/12Z TAFS/...

AREA OF SHOWERS AND A FEW STORMS WILL SHIFT EAST NORTHEAST THROUGH
THE AREA INTO THE MIDDLE MORNING HOURS. MAY SEE MVFR VISIBILITIES
AND CEILINGS WITH THESE SHOWERS. GUSTY SOUTH SOUTHWEST WINDS ARE
EXPECTED BY THE AFTERNOON HOURS...WITH GUSTS TO 25 KNOTS AT TIMES.

COLD FRONT WILL PUSH EASTWARD THROUGH TAF SITES BETWEEN 21Z TODAY
AND 03Z TUESDAY. SHOWERS AND STORMS ARE POSSIBLE ALONG AND AHEAD OF
THE FRONT. STRONG/SEVERE STORMS ARE POSSIBLE WITH HAIL AND GUSTY
WINDS. UNCERTAINTY EXISTS WITH THE AREAL COVERAGE OF STORMS...SO
WILL JUST USE VICINITY THUNDER WORDING FOR NOW IN TAFS. MVFR/IFR
VISIBILITIES AND CEILINGS ARE POSSIBLE IN ANY STORMS.

QUIET WEATHER WILL RETURN AFTER THE FRONTAL PASSAGE AND LINGER
THROUGH THE REST OF TONIGHT. LIGHT WINDS AND LINGERING MOISTURE MAY
BRING MVFR/IFR FOG AND CEILINGS TO THE AREA AFTER 06Z TUESDAY.


MARINE...

CANCELLED MARINE DENSE FOG ADVISORY EARLY...AS INCREASING SOUTH
WINDS SHOULD MIX OUT ANY LINGERING FOG NORTH OF NORTH POINT
LIGHTHOUSE.

SMALL CRAFT ADVISORY CONTINUES FOR THE NEARSHORE WATERS FROM 15Z
UNTIL 23Z TODAY. TIGHT PRESSURE GRADIENT WILL ALLOW FOR GUSTY SOUTH
SOUTHWEST WINDS TO 25 KNOTS AT TIMES. THIS WILL BRING WAVES OF 3 TO
5 FEET TOWARD THE OPEN WATERS. WINDS AND WAVES WILL SUBSIDE BY THIS
EVENING.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR LMZ643>646.

&&

$$
TODAY/TONIGHT AND AVIATION/MARINE...WOOD
TUESDAY THROUGH SUNDAY...DDV


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