Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 041559 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
959 AM CST WED MAR 4 2015

.UPDATE...

NO CHANGES TO CURRENT FORECAST FOR TODAY.

&&

.AVIATION/18Z TAFS/...

A COLD LOW LEVEL NORTHWEST FLOW AND LINGERING MOISTURE WILL CAUSE
SCATTERED TO OCCASIONALLY BROKEN CLOUDS AROUND 2500 TO 3000 FEET.
AS DRIER AIR MOVES IN TONIGHT SKIES SHOULD EVENTUALLY CLEAR.

A BRISK NORTHWEST WIND WILL PERSIST TODAY AHEAD OF HIGH PRESSURE
OVER THE NORTHERN PLAINS.  STEEP LOW LEVEL LAPSE RATES WILL ALLOW
MIXING OF 25 KNOT GUSTS TO THE SURFACE INTO THE EARLY AFTERNOON...
THEN SLOWLY EASING AS THE HIGH MOVES TOWARD THE UPPER MISSISSIPPI
VALLEY TONIGHT.

&&

.MARINE...

WILL CONTINUE SMALL CRAFT ADVY FOR NOW.  STILL EXPECT OCCASIONAL
GUSTS AROUND 25KTS TODAY BUT WEAKENING PRESSURE GRADIENT WILL ALLOW
HIGHER GUSTS TO GRADUALLY DIMINISH THIS AFTN INTO THIS EVE.  LATEST
VSBL HI RES IMAGERY FROM MARCH 2 SHOWING MORE OPEN WATER SO WL ADD
SOME WAVES TO THE NEARSHORE FORECAST.

&&

.PREV DISCUSSION... /ISSUED 220 AM CST WED MAR 4 2015/

TODAY AND TONIGHT... FORECAST CONFIDENCE HIGH.

A STRONG 170 TO 180 KNOT 250 MB JET MAX EXTENDS FROM THE MID
MISSISSIPPI VALLEY TO THE EASTERN GREAT LAKES.  THE CORE OF THE JET
MAX INCREASES TO 190 KNOTS FROM SOUTHEAST WISCONSIN TO 210 KNOTS
OVER THE EASTERN GREAT LAKES BY EVENING. THIS PLACES SOUTHERN
WISCONSIN CLOSE TO PORTIONS OF THE ENTRANCE REGION WITH UPPER LEVEL
DIVERGENCE INCREASING JUST TO THE SOUTH AND EAST. THE JET MAX PUSHES
SOUTH AND EAST AS THE UPSTREAM TROUGH AXIS REACHES WESTERN WISCONSIN
TOWARD SUNRISE THURSDAY.  THIS PLACES THE LEFT ENTRANCE REGION OF
THE JET OVER THE AREA THIS EVENING.  A 500 MB MID LEVEL TROUGH AXIS
REACHES WISCONSIN LATE TONIGHT WITH CYCLONIC VORTICITY ADVECTION
OCCURRING TONIGHT.  DOWNWARD MOTION OCCURS ACROSS SOUTHERN WISCONSIN
FOR MUCH OF THE TIME...BUT MAY BECOME UPWARD BRIEFLY AS THE MID
LEVEL TROUGH MOVES IN LATE TONIGHT.  THE 700 MB LAYER REMAINS
DRY...WITH HIGHER 925 MB MOISTURE...ALTHOUGH NOT SATURATED.
THEREFORE EXPECT MAINLY SCATTERED TO OCCASIONALLY BROKEN
STRATOCUMULUS POTENTIAL WITH MOST OF THE HIGH CIRRUS STAYING JUST TO
THE SOUTH AND EAST.

THE MAIN CONCERN WILL BE THE LOW LEVEL COLD AIR ADVECTION.
STRONGEST 850 MB COLD AIR ADVECTION OCCURS THIS AFTERNOON AND
EVENING.  THEREFORE EXPECT A QUICK DROP IN TEMPERATURES LATER THIS
AFTERNOON AND EVENING.  EXPECT SUB ZERO TEMPERATURES LATE TONIGHT
BUT SURFACE WINDS WILL BE DIMINISHING AS THE SURFACE HIGH BUILDS
INTO THE UPPER MISSISSIPPI VALLEY.  A FEW WIND CHILLS MAKE IT TO 20
BELOW...BUT NOT WIDESPREAD OR LONG ENOUGH FOR A WIND CHILL
ADVISORY.

THURSDAY...FORECAST CONFIDENCE...HIGH

HIGH PRESSURE WILL MOVE OVERHEAD THURSDAY. EXPECT DRY WEATHER WITH
PLENTY OF SUNSHINE. UNFORTUNATELY...THE VERY COLD AIRMASS WILL
REMAIN IN PLACE...WITH WELL BELOW NORMAL TEMPERATURES EXPECTED.
WIND CHILLS WILL STRUGGLE UP TO AROUND ZERO BY AFTERNOON.

FRIDAY THROUGH TUESDAY...FORECAST CONFIDENCE...MEDIUM

EXPECT A COUPLE OF WEAK WAVES TO MOVE THROUGH PREVAILING NORTHWEST
FLOW FRIDAY THROUGH SUNDAY...WITH SOME FLURRIES OR LITTLE LIGHT
SNOW POSSIBLE AT TIMES. TEMPS ARE EXPECTED TO WARM TO AROUND
NORMAL VALUES FOR THE WEEKEND.

THE FLOW WILL TURN MORE ZONAL FOR EARLY NEXT WEEK...ALLOWING FOR
MILDER AIR TO MOVE INTO SOUTHERN WISCONSIN. COULD SOME 40S FOR THE
FIRST TIME SINCE THE MIDDLE OF JANUARY...MAYBE EVEN 50 BY
TUESDAY...WHICH HAS NOT HAPPENED SINCE MID-DECEMBER. THERE IS
INCREASING CONFIDENCE IN THIS MILDER AIR...AS THE GFS HAS TRENDED
TOWARD THE MILDER ECMWF COMPARED TO 24 HOURS AGO.

AVIATION/12Z TAFS/...

A STRONG 170 TO 180 KNOT 250 MB JET MAX EXTENDS FROM THE MID
MISSISSIPPI VALLEY TO THE EASTERN GREAT LAKES.  THE CORE OF THE JET
MAX INCREASES TO 190 KNOTS FROM SOUTHEAST WISCONSIN TO 210 KNOTS
OVER THE EASTERN GREAT LAKES BY EVENING.

A COLD LOW LEVEL NORTHWEST FLOW AND LINGERING MOISTURE WILL CAUSE
SCATTERED TO OCCASIONALLY BROKEN CLOUDS AROUND 25 HUNDRED FEET.  AS
DRIER AIR MOVES IN TONIGHT SKIES SHOULD EVENTUALLY CLEAR. A BRISK
NORTHWEST WIND WILL PERSIST AHEAD OF HIGH PRESSURE OVER THE NORTHERN
PLAINS.  STEEP LOW LEVEL LAPSE RATES WILL ALLOW MIXING OF 25 KNOT
GUSTS TO THE SURFACE INTO THE EARLY AFTERNOON...THEN SLOWLY EASING
AS THE HIGH MOVES TOWARD THE UPPER MISSISSIPPI VALLEY.

MARINE...

A BRISK NORTHWEST WIND WILL PERSIST AHEAD OF HIGH PRESSURE OVER THE
NORTHERN PLAINS.  STEEP LOW LEVEL LAPSE RATES WILL ALLOW MIXING OF
25 KNOTS TO THE SURFACE. THEREFORE EXPECT FREQUENT SMALL CRAFT
ADVISORY LEVEL GUSTS INTO THE EARLY AFTERNOON THEN SLOWLY EASING AS
THE HIGH MOVES TOWARD THE UPPER MISSISSIPPI VALLEY.

&&

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

&&

$$

UPDATE...MRC/MBK
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...DDV


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