Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 222026
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
226 PM CST SUN FEB 22 2015

.SHORT TERM...

.TONIGHT AND MONDAY... FORECAST CONFIDENCE HIGH.

SURFACE HIGH PRESSURE WILL DRIFT FROM SOUTHWEST MINNESOTA TO
ILLINOIS TONIGHT THROUGH MONDAY AFTERNOON. THE TIGHT PRESSURE
GRADIENT WILL EASE OVER SOUTHERN WI TONIGHT... AND THEN INCREASE
MONDAY AFTERNOON AS LOW PRESSURE APPROACHES FROM SOUTHERN CANADA.
THE HIGH WILL BRING A CORE OF ARCTIC AIR INTO THE REGION.

925MB TEMPS WILL DROP TO -22 TO -24C WHICH TRANSLATES TO THE LOWER
TO MID TEENS BELOW ZERO FAHRENHEIT. COLDEST TEMPS WILL BE TOWARD
WESTERN AND CENTRAL WI... CLOSER TO THE CORE OF THE HIGH. WINDS
COULD DECOUPLE THERE WHICH WOULD ALLOW TEMPS TO DROP LOWER THAN
FORECAST... BUT WIND CHILL TEMPS WOULD NOT BE QUITE AS LOW.
OVERALL... EXPECTING NORTHWEST WINDS TO REMAIN ELEVATED AT 5 TO 10
MPH... SO MINIMUM WIND CHILL VALUES WILL BE IN THE 20 TO 30 BELOW
RANGE FROM MID EVENING THROUGH MID MONDAY MORNING. A WIND CHILL
ADVISORY IS IN EFFECT.

TEMPERATURES WILL REBOUND UP TO AROUND 10 DEGREES BY MONDAY
AFTERNOON. WINDS WILL REMAIN BRISK OUT OF THE WEST AND EVENTUALLY
BECOME SOUTHWEST LATE WITH RETURN FLOW AROUND THE HIGH.

.MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE HIGH.

A SPLIT FLOW DEVELOPS IN THE UPPER LEVELS WITH A NORTHERN TROUGH
MOVING ACROSS WISCONSIN. THE STRONGER MID LEVEL TROUGH BRUSHES THE
NORTHERN GREAT LAKES WITH THE CYCLONIC VORTICITY MAXIMUM MOVING ACROSS
THE NORTHERN GREAT LAKES...NORTHEAST OF OUR AREA. WEAK UPPER
DIVERGENCE WITH WEAK UPWARD 700 MB LIFT ACROSS SOUTHERN WISCONSIN
MONDAY NIGHT AND MAINLY SOUTHEAST WISCONSIN TUESDAY. MODERATE
925/850/700 MB WARM AIR ADVECTION MONDAY NIGHT WITH WEAKER COLD
AIR ADVECTION BY TUESDAY AFTERNOON.

A BAND OF HIGH RELATIVE HUMIDITY AT 925/850/700 MB SWINGS DOWN
ACROSS SOUTHERN WISCONSIN MAINLY TUESDAY MORNING WITH DRYING
TUESDAY AFTERNOON. HIGH 925 MB RH REMAINS LONGER INTO TUESDAY
AFTERNOON WITH SOME DRYING FROM THE NORTH LATE.

THE SURFACE LOW IS NORTH OF THE GREAT LAKES WITH A TRAILING COLD
FRONT REACHING THE AREA TUESDAY AFTERNOON.

THE NAM BRINGS A BAND OF LIGHT SNOW WITH THE FRONT...BUT THE GFS
AND ECMWF ARE BOTH DRIER...WITH THE 00Z ECMWF HAVING NO MEASURABLE
PRECIPITATION EXCEPT TOWARDS SHEBOYGAN TUESDAY AFTERNOON. WILL
CONTINUE THE LOW MENTION OF LIGHT SNOW.

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

THE BASE OF THE INITIAL NORTHERN STREAM TROUGH EXTENDS ACROSS THE
GREAT LAKES TO THE NORTHEAST U.S. WEDNESDAY....WITH A SECOND
TROUGH AXIS APPROACHING THE UPPER MISSISSIPPI VALLEY WEDNESDAY
AFTERNOON. VERY WEAK UPPER DIVERGENCE WITH MAINLY WEAK DOWNWARD
MOTION AT 700 MB. 700 MB RH IS LOW. THE 925/850 MB RH DRIES
TUESDAY EVENING WITH 925 MB RH INCREASING AGAIN WEDNESDAY
AFTERNOON.

ANOTHER COLD SURFACE HIGH NORTH OF MONTANA AND THE DAKOTAS...
BUILDS INTO THE UPPER MISSISSIPPI VALLEY WITH NORTH LOW LEVEL
WINDS AND COLD AIR ADVECTION.


.LONG TERM...

.WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE HIGH.

THE SPLIT FLOW BREAKS DOWN AS THE NORTHERN TROUGH BUILDS BACK
TOWARD THE SOUTHWEST WITH THE TROUGH AXIS ACROSS WISCONSIN
TOWARDS THE CENTRAL PLAINS.

THE COLD SURFACE HIGH SAGS ACROSS THE PLAINS AND UPPER
MISSISSIPPI VALLEY INTO WISCONSIN. AS THE HIGH MOVES ACROSS...
WELL BELOW NORMAL TEMPERATURES WILL HAVE A FIRM GRIP ON THE
REGION. WITH LIGHT WINDS LOW TEMPERATURES WILL BE VERY COLD IF
SKIES ARE MOSTLY CLEAR. WITH LIGHT WINDS...WINDS CHILLS WILL
NOT BE MUCH OF A FACTOR.

.THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE HIGH.

THE NORTHERN STREAM BECOMES A BIT MORE ZONAL AS IT WEAKENS AND A
STRONG SHORTWAVE MOVES SOUTH ACROSS THE WESTERN U.S.

THE CENTER OF THE COLD SURFACE HIGH IS CENTERED ACROSS WISCONSIN
THURSDAY NIGHT AND PUSHES A LITTLE EAST FRIDAY CONTINUING THE VERY
COLD TEMPERATURES. HOWEVER WITH LIGHT WINDS...WINDS CHILLS WILL
NOT BE A FACTOR.

.SATURDAY AND SUNDAY...FORECAST CONFIDENCE MEDIUM.

THE WESTERN SHORTWAVE REACHES THE SOUTHWEST U.S. WITH A WEST
SOUTHWEST FLOW ACROSS THE PLAINS TO WISCONSIN.

MODEL DIFFERENCES CONTINUE WITH THE TIMING AND STRENGTH OF ANY
EJECTING SHORTWAVES. THE 00Z ECMWF HAS TWO SHORTWAVES PUSHING
EAST NORTHEAST...THE FIRST WOULD MOVE WELL SOUTH OF WISCONSIN.
THE GFS IS MUCH WEAKER WITH ANY EJECTING SHORTWAVES. THE 12Z ECMWF
IS MUCH CLOSER TO THE 12Z GFS.

THE GFS BRINGS IN MORE PRECIPITATION SATURDAY NIGHT AND SUNDAY
THAN THE 00Z ECMWF. THE GFS WOULD BRING SEVERAL INCHES OF SNOW TO
SOUTHERN WISCONSIN. THE 00Z ECMWF WOULD ONLY BEGIN SOME LIGHT SNOW
SUNDAY AFTERNOON. HOWEVER THE NEW 12Z ECMWF IS SIMILAR TO THE 12Z
GFS WITH SEVERAL INCHES OF SNOW.

&&

.AVIATION/00Z TAFS/...

VFR CONDITIONS WILL PREVAIL THROUGH MONDAY EVENING AS HIGH PRESSURE
SLIDES SOUTHEAST FROM MINNESOTA TO SOUTHERN ILLINOIS. NORTHWEST
WINDS WILL EASE SOMEWHAT TONIGHT INTO MONDAY MORNING... THEN BECOME
WEST TO SOUTHWEST MONDAY AFTERNOON. LOOK FOR STRONG AND GUSTY
SOUTHWEST WINDS MONDAY NIGHT AS LOW PRESSURE TRACKS ACROSS LAKE
SUPERIOR. LOW LEVEL WIND SHEAR IS POSSIBLE MONDAY NIGHT AS WELL...
WITH 40 TO 50 KNOT WSW WINDS AT 2000 FEET AGL.

&&

.MARINE...

WINDS WILL SHIFT TO THE SOUTHWEST MONDAY AFTERNOON AS HIGH PRESSURE
SLIDES INTO THE CENTRAL U.S. AND LOW PRESSURE TRACKS ACROSS LAKE
SUPERIOR. HIGH-END SMALL CRAFT ADVISORY WINDS AND GUSTS ARE EXPECTED
MONDAY NIGHT THROUGH TUESDAY. GALE FORCE GUSTS ARE POSSIBLE LATE
MONDAY NIGHT.

THE LATEST MODIS SATELLITE IMAGERY STILL SHOWS A LAYER OF ICE OVER
THE NEARSHORE WATERS OF SOUTHEAST WISCONSIN.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 10 AM CST MONDAY
     FOR WIZ046-047-051-052-056>060-062>072.

LM...NONE.
&&

$$

TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...HENTZ


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