Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 231455 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
955 AM CDT THU APR 23 2015

.UPDATE...

CUMULUS DEVELOPMENT IS EXPECTED THIS MORNING INTO EARLY
AFTERNOON...PARTICULARLY ACROSS THE NORTHEAST FORECAST AREA.
SOUNDINGS SHOW MORE DRYING IN THE LOW LEVELS THROUGH THE
AFTERNOON...SO SHOULD SEE DECREASING CLOUD COVER AS THE AFTERNOON
GOES ON. OTHERWISE...FORECAST HIGH TEMPERATURES SEEM TO BE ON
TRACK...WITH HIGHS RANGING FROM AROUND 50 NORTHEAST...TO 55
SOUTHWEST.

&&

.AVIATION/18Z TAFS/...

VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE DAY FRIDAY.
WILL SEE INCREASING CLOUDS LATER TONIGHT AND INTO FRIDAY AHEAD OF
APPROACHING LOW PRESSURE. LATEST SOUNDINGS SUGGEST THAT THE DRY
AIR IN THE LOWER LEVELS WILL HOLD ON FOR QUITE A WHILE...LIKELY
KEEPING THE AREA MAINLY DRY THROUGH THE DAYTIME HOURS. A LITTLE
LIGHT RAIN MAY SNEAK INTO THE WEST BY EVENING PER SOME OF THE
MODELS...THOUGH THE NAM KEEPS IT DRY UNTIL AFTER MIDNIGHT. THE
DRIER AIR SHOULD ALSO KEEP CIGS GENERALLY AT OR ABOVE 5 KFT
THROUGH LATE FRIDAY AFTERNOON.

&&

.MARINE...WEAKENING PRESSURE GRADIENT ACROSS LAKE MI AND WESTERN
GTLAKES WILL ALLOW NORTHWEST WINDS TO TURN ONSHORE EARLY THIS
AFTERNOON.  LAKE SURFACE TEMP REMAIN IN THE MID TO UPPER 30S.
ONSHORE WINDS WILL BECOME OFFSHORE THIS EVENING AND THEN MORE
VARIABLE OVERNIGHT AS HIGH PRESSURE RIDGE PASSES ACROSS WRN GTLAKES.

&&

.PREV DISCUSSION... /ISSUED 328 AM CDT THU APR 23 2015/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

THE LARGE POLAR TROUGH CENTERED OVER ERN ONTARIO AND WRN QUEBEC
CANADA WILL FINALLY SHIFT EWD WITH 500 HEIGHT RISES OF 120 M OVER
SRN WI. LOW LEVEL INSTABILITY WILL LINGER DURING THE MORNING INTO
THE EARLY AFTERNOON OVER FAR ERN WI BUT SUBSIDENCE AND DRYING WILL
DOMINATE AFTERWARD. THUS SCT-BKN STRATOCUMULUS EXPECTED OVER ERN
WI FROM 15Z-18Z WITH SKY CONDITIONS IMPROVING TOWARD LATE
AFTERNOON.

FORECAST 925 MB TEMPS OF 3-5C YIELDS HIGH TEMPS IN THE LOWER TO
MID 50S FOR TODAY. DO EXPECT A LAKE BREEZE TODAY BUT WITH LITTLE
INLAND PENETRATION GIVEN THE NWLY FLOW INLAND. FOR TNT...HEIGHT
RISES WILL CONTINUE WITH THE SFC RIDGE SETTLING OVER WI. COLD
TEMPS...BELOW FREEZING EXPECTED.

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

MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE LOW PRESSURE SYSTEM
AFFECTING THE REGION FRIDAY NIGHT INTO SATURDAY. CONSENSUS OF
MODELS TAKE THE LOW FROM THE CENTRAL HIGH PLAINS FRIDAY INTO
NORTHWEST MISSOURI FRIDAY NIGHT...THEN INTO SOUTHEAST ILLINOIS
SATURDAY.

ASSOCIATED 500 MB SHORTWAVE TROUGH SLIDES EAST SOUTHEAST FROM THE
NORTHERN PLAINS TO NORTHWEST INDIANA DURING THIS PERIOD. UPWARD
VERTICAL MOTION IS BEST ON SATURDAY IN THE SOUTHERN PORTIONS OF
THE AREA...AS THE SHORTWAVE TROUGH MOVES THROUGH THE AREA. BEST
WARM AIR ADVECTION REMAINS JUST SOUTH OF THE AREA SATURDAY.

AREA FORECAST SOUNDINGS INDICATING MORE DEEP COLUMN MOISTURE ON
GFS VERSUS NAM FRIDAY NIGHT INTO SATURDAY...BEST IN THE SOUTH.
CONTINUED WITH THE HIGHEST POPS IN THE SOUTH AND SOUTHWEST
COUNTIES FRIDAY NIGHT INTO SATURDAY. MAY GET COLD ENOUGH LATER
FRIDAY NIGHT INTO EARLY SATURDAY FOR A MIX OF LIGHT RAIN AND LIGHT
SNOW IN PARTS OF THE NORTHERN AND EASTERN COUNTIES.

INCREASING ONSHORE WINDS FRIDAY INTO SATURDAY WILL KEEP COLDER
TEMPERATURES NEAR LAKE MICHIGAN...WITH BELOW NORMAL TEMPERATURES
ACROSS THE ENTIRE AREA BOTH DAYS.

LONG TERM...SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE IS
MEDIUM.

GFS/ECMWF IN GENERAL AGREEMENT WITH HIGH PRESSURE TO THE NORTH OF
THE REGION SUNDAY INTO MONDAY NIGHT...WITH WEAK 500 MB RIDGE
SLIDING SOUTHEAST INTO THE REGION. THIS SHOULD RESULT IN A PERIOD
OF QUIET WEATHER. MORE SEASONABLE TEMPERATURES SHOULD OCCUR AWAY
FROM LAKE MICHIGAN...WITH ONSHORE WINDS KEEPING LAKESHORE AREAS
COOLER.

MODELS THEN KEEP THE AREA DRY TUESDAY INTO WEDNESDAY...SHOWING
DIFFERENT TIMING AND PLACEMENT OF PASSING 500 MB SHORTWAVE TROUGH.
ECMWF BRINGS IT THROUGH THE AREA TUESDAY...WITH THE GFS KEEPING IT
TO THE SOUTHWEST OF THE AREA. THIS IS QUITE A SHIFT FROM THE PAST
FEW DAYS...WHICH HAD THE AREA SEEING SOME LIGHT QPF. FOR
NOW...WILL USE CONSENSUS POPS AND TEMPERATURES...BUT THESE MAY
NEED TO BE REMOVED IN LATER FORECASTS IF DRY LOOK CONTINUES.

AVIATION/12Z TAFS/...

VFR CONDITIONS TODAY AND TNT AS HIGH PRESSURE BUILDS INTO WI.
SCT-BKN040-050 STRATOCUMULUS OVER ERN WI FROM 15Z-18Z THEN FEW-SCT
AFTERWARD.

&&

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

$$

UPDATE...DDV/MBK
TODAY/TONIGHT AND AVIATION...GEHRING
FRIDAY THROUGH WEDNESDAY...WOOD



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