Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KMKX 281547 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1047 AM CDT TUE JUL 28 2015

.UPDATE...

TWO AREAS OF PRECIPITATION CONTINUE TO MOVE TOWARD THE
AREA...DRIVEN MAINLY BY 700 MB WARM AIR ADVECTION AND A PASSING
500 MB VORTICITY MAXIMUM. THE FIRST BATCH HAS SHOWN SOME WEAKENING
TRENDS IN THE PAST FEW RADAR SCANS...AND SHOULD SLOWLY WEAKEN OVER
THE NEXT HOUR OR TWO.

THE SECOND AREA HAS BECOME MORE ORGANIZED INTO A CONVECTIVE LINE
OVER EASTERN IOWA IN THE PAST HOUR. THERE IS A COLD POOL BEHIND
IT...SO THIS MAY CONTINUE EAST SOUTHEAST INTO THE AFTERNOON HOURS.
HOW FAR EAST IS THE BIG QUESTION.

THE TWO HRRR MODEL VERSIONS ARE SHOWING DIFFERING
SOLUTIONS...WITH ONE TAKING IT THROUGH MOST OF THE AREA THIS
AFTERNOON...AND THE OTHER WIPING IT OUT OVER THE NEXT FEW HOURS.

FOR NOW...INCREASED POPS QUITE A BIT IN THE FAR WESTERN COUNTIES
OVER THE NEXT FEW HOURS...AS THIS AREA SHOULD SEE SOME MEASURABLE
PRECIPITATION. KEPT LOWER POPS TO THE EAST OF THERE...GIVEN SOME
UNCERTAINTY WITH HOW FAR EAST THIS PRECIPITATION WILL GET.

MEAN LAYER CAPES ARE NOT EXPECTED TO GET VERY HIGH...AND DEEP
LAYER SHEAR IS WEAK...SO NOT EXPECTING ANY SEVERE WEATHER. COULD
SEE GUSTY WINDS TO AROUND 25 KNOTS WITH THE LINE OF STORMS...IF
THEY MAKE IT INTO THE WESTERN COUNTIES. LOCALLY HEAVY RAINFALL IS
POSSIBLE GIVEN HIGH PRECIPITABLE WATER VALUES.

THE INCREASE IN CLOUDS MAY ALSO LIMIT HIGHS THIS
AFTERNOON...THOUGH MOST OF THE AREA IS ALREADY INTO THE LOWER 80S.
STILL MAY NEED TO ADJUST TEMPERATURES DOWNWARD FOR THIS AFTERNOON.

&&

.AVIATION/18Z TAFS/...

MADISON MAY SEE SOME SHOWER ACTIVITY WITH THE FIRST BATCH OF
PRECIPITATION LATER THIS MORNING...THOUGH THIS MAY DISSIPATE
BEFORE REACHING THERE. THE SECOND LINE OF SHOWERS/STORMS MAY BRING
BRIEF GUSTY WINDS TO 25 KNOTS BY EARLY THIS AFTERNOON IF IT HOLDS
TOGETHER...BUT THERE IS UNCERTAINTY IF THIS WILL MAKE IT THERE
TOO. FOR NOW...WILL MENTION RAIN SHOWERS IN TAF BUT MAY LEAVE OUT
THUNDER. MAY SEE BRIEF MVFR VISIBILITIES AND CEILINGS WITH THE
SHOWERS AND STORMS.

BROKEN TO OVERCAST MIDDLE TO HIGH CLOUDS ASSOCIATED WITH
PRECIPITATION SHOULD LINGER ACROSS THE AREA FOR MOST OF THE REST
OF TODAY. LIGHT/MODERATE SOUTH/SOUTHEAST WINDS ARE EXPECTED.

AREA OF SHOWERS AND THUNDERSTORMS ARE LIKELY WITH THE COLD FRONTAL
PASSAGE LATER TONIGHT INTO EARLY WEDNESDAY MORNING ACROSS TAF
SITES. MAY SEE MVFR VISIBILITIES AND CEILINGS AT TIMES. WILL
CONTINUE TO MENTION PREVAILING THUNDER WEST TO EAST IN TAFS LATER
TONIGHT INTO EARLY WEDNESDAY MORNING.

GUSTY WEST WINDS ARE EXPECTED WEDNESDAY BEHIND THE FRONT...WITH
GUSTS TO AROUND 20 KNOTS POSSIBLE. VFR CONDITIONS ARE EXPECTED
WEDNESDAY AT ALL SITES.

&&

.PREV DISCUSSION... /ISSUED 310 AM CDT TUE JUL 28 2015/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

CONVECTION FROM THE OVERNIGHT QLCS COMPLEX OVER THE NORTHERN PLAINS
SHOULD BE APPROACHING OUR WESTERN FORECAST AREA BY AROUND MID DAY.
THE MESO MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THAT. BUT IT WILL
BE GOING THROUGH THE TYPICAL DIURNAL DISSIPATION...SO ANTICIPATING
JUST HOW FAR EAST IT WILL GET BEFORE WIPING OUT IS CHALLENGING. THE
AIRMASS OVER SOUTHERN WISCONSIN IS QUITE DRY AND STABLE. I/LL KEEP
IT MOSTLY WEST OF MADISON. THEN WE SHOULD BE QUIET FROM MID
AFTERNOON TO EARLY EVENING. 925MB TEMPS WILL BE IN THE 23-24C
RANGE...SO ANOTHER WARM AFTERNOON WITH HIGHS IN THE MID 80S ALONG
WITH RISING DEWPOINTS. TEMPS WILL BE TRICKY WITH CLOUD COVER
SOMEWHAT UNCERTAIN GIVEN MORNING CONVECTIVE DEBRIS.

ATTENTION WILL THEN FOCUS ON THE NEXT ROUND OF STORMS FOR TONIGHT. A
COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST...EVENTUALLY
REACHING MADISON TOWARD SUNRISE WEDNESDAY.  THE SEVERE POTENTIAL IS
LIMITED BY A RATHER WEAK WIND FIELD THROUGH THE COLUMN AND A LATER
ARRIVAL TIME OF THE CONVECTION.  MOISTURE WILL BE INCREASING RAPIDLY
LATE THIS AFTERNOON AS PRECIPITABLE WATER VALUES INCREASE BY ABOUT
AN INCH...TO JUST OVER 2 INCHES BY THIS EVENING.  HOW THE CONVECTION
DEVELOPS WILL BE INFLUENCED GREATLY BY THE OUTFLOW FROM THE MORNING
CONVECTION. THUS...THERE ARE A FEW SCENARIOS AMONG THE MODELS WITH
REGARD TO TIMING/COVERAGE OF THE OVERNIGHT PRECIP. THE MID LEVELS
SHOW THE UPPER RIDGE BEING FLATTENED BY SOME SHORT WAVE ENERGY
ALREADY THIS EVENING. THIS IS AHEAD OF A MUCH LARGER UPPER LOW OVER
SOUTH CENTRAL CANADA/NCNTRL U.S. GIVEN THAT DISTANCE...THE MID LEVEL
FLOW WILL REMAIN WEAK OVER SOUTHERN WISCONSIN. IT LOOKS LIKE THE
NEXT ROUND WILL MOSTLY STAY BACK CLOSER TO THE LOW LEVEL FRONT AS
FORCING AHEAD OF IT WILL BE ON THE WEAK SIDE. JUST CAN/T RULE OUT
SOME LEADING SHOWERS/STORMS. THERE SHOULD BE A DECENT RIBBON OF HIGH
SFC DEWPOINTS RIDING JUST AHEAD OF THE SFC FRONT AS WELL. CAPE
VALUES ARE NOTHING SPECIAL...IN THE 700-1300J/KG RANGE. HOPEFULLY...WE
CAN GET SOME WIDESPREAD RAINFALL...AS CONDITIONS HAVE DRIED OUT
QUITE A BIT LATELY.

WEDNESDAY - CONFIDENCE...MEDIUM
SURFACE FRONT EXITS ERN WI VERY EARLY IN THE DAY WITH POTENTIAL
FOR SOME LINGERING SHRA. HOWEVER WARM WESTERLY FLOW WILL KICK IN
WITH 925 TEMPS IN THE 21-23C RANGE. EXPECTING A DROPOFF IN DEW
POINTS BUT NOT SO IN THE TEMP DEPT. SHOULD SEE A GOOD DEAL OF
SUNSHINE ONCE CLOUD COVER ASSOCIATED WITH FRONT EXITS ERN WI.

THURSDAY - CONFIDENCE...MEDIUM
WNW MID LEVEL FLOW CONTINUES WITH SHORTWAVE PASSING BY ACRS NRN
WI AND INTO THE U.P. NOT MUCH IN THE WAY OF FORCING HERE WITH 925
TEMPS RISING BACK UP...ESPECIALLY ON THE GFS WHERE 925 TEMPS SURGE
AS HIGH AS 26C. SO WITH THE WESTERLY LOW LEVEL FLOW CONTINUING
EXPECT TEMPS TO BE RATHER WARM...AT LEAST WELL INTO THE 80S.

FRIDAY - CONFIDENCE...MEDIUM
850 THERMAL RIDGE EXTENDS INTO SRN WI WITH SURFACE/850 TROUGH
PROGGD TO SWING THROUGH. GFS SHOWS SPOTTY PRECIP THOUGH NOT MUCH
UPPER SUPPORT TO LATCH ONTO. SPOTTY PRECIP ON GFS IS SOUTH OF THE
AREA AND 00Z ECMWF HAS COME IN DRIER THAN THE 12Z RUN. PER COLLAB
WITH KLOT HAVE ELECTED TO REMOVE THE SMALL SUPERBLEND POPS THAT
WERE SHOWN FOR THE ERN CWA.

SATURDAY - CONFIDENCE...MEDIUM
SURFACE RIDGE AXIS SLIDES ACROSS AND TO THE SOUTH OF WI THIS
PERIOD. PRECIP CHANCES ARE LOOKING TO REMAIN TO OUR WEST WITH THE
NEXT APPROACHING TROUGH. 925 TEMPS ARE PROGGD TO STILL BE IN THE
LOWER 20S CELSIUS SO MORE 80S IN THE WORKS.

SATURDAY NIGHT THROUGH MONDAY - CONFIDENCE...MEDIUM
APPEARS THERE MAY BE A COUPLE OF DIFFERENT FRONTAL BOUNDARIES
THAT GENERATE PRECIP THIS PERIOD WITH STRONG WNW UPPER FLOW
PERSISTING.

AVIATION/12Z TAFS/...OVERNIGHT CONVECTION IN THE NORTHERN PLAINS
WILL BE APPROACHING WESTERN WISCONSIN BY LATE MORNING...BUT SHOULD
DISSIPATE BEFORE REACHING KMSN. THEREFORE LOOK FOR QUIET...VFR
CONDITIONS THROUGH ABOUT MID EVENING. ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS IS EXPECTED ACROSS THE AREA TONIGHT ALONG AND AHEAD
OF AN APPROACHING COLD FRONT. THE BEST CHANCE FOR STORMS AT KMSN
WILL BE LATE THIS EVENING OR AROUND MIDNIGHT AND A FEW HOURS LATER
AT KMKE/KUES/KENW. THE STORMS SHOULD WE WEAKENING IN INTENSITY AND
COVERAGE BY THE TIME THEY REACH EASTERN WISCONSIN LATER TONIGHT.
MVFR CONDITIONS ARE POSSIBLE AS THE SHOWERS AND STORMS MOVE
THROUGH.

&&

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

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.