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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
330 AM CST FRI JAN 30 2015

.SHORT TERM...

TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

A NORTHWEST UPPER FLOW WILL CONTINUE ACROSS SOUTHERN WISCONSIN WITH 
THE MAIN UPPER JET ACROSS THE MID MISSISSIPPI VALLEY.  THE 250 MB 
JET MAX LIFTS NORTH DURING THE DAY AND REACHES SOUTHERN WISCONSIN 
AROUND SUNRISE SATURDAY AT 140 KNOTS...WITH THE ENTRANCE REGION JUST 
TO THE NORTHWEST.  MAINLY WEAK UPPER LEVEL CONVERGENCE UNTIL SUNRISE 
SATURDAY. 
 

DOWNWARD MOTION AT 700 MB GIVES WAY TO VERY WEAK UPWARD MOTION 
TONIGHT. A BAND OF HIGHER MID LEVEL 700 MB RH MOVES ACROSS SOUTHERN 
WISCONSIN AROUND NOON WITH THE HIGHER RH NEAR AND JUST NORTH OF 
SHEBOYGAN TONIGHT. VERY WEAK 700 MB WARM AIR ADVECTION TODAY AND 
TONIGHT WITH A LITTLE STRONGER 850 MB WARM AIR ADVECTION... 
ESPECIALLY TONIGHT.  
 
850 MB RH DRIES BY SUNRISE...BUT THE 925 MB RH IS SLOWER TO DRY... 
BUT DOES SLOWLY DRY FROM THE WEST DURING THE DAY. 

THE SURFACE HIGH CENTERED OVER THE UPPER MISSISSIPPI VALLEY MOVES 
ACROSS SOUTHERN WISCONSIN BY NOON...AND REACHES THE EASTERN GREAT 
LAKES BY MIDNIGHT. 

.LONG TERM...

SATURDAY THROUGH SUNDAY... FORECAST CONFIDENCE MEDIUM.

PLAN ON QUIET WEATHER SATURDAY WITH SURFACE HIGH PRESSURE GRADUALLY 
DEPARTING SOUTHERN WI. CLOUDS WILL BE INCREASING THROUGH THE DAY AND 
TEMPS SHOULD RISE INTO THE LOWER 30S. WINDS WILL PRIMARILY BE OUT OF 
THE SOUTHWEST TO WEST DURING THE DAY. THEN WINDS WILL SHIFT TO 
NORTHEAST SATURDAY EVENING ALONG A BACK DOOR COLD FRONT. 

1000-850MB WINDS WILL BECOME NORTHEAST SAT EVENING WITH HIGH RH IN 
THE DENDRITIC GROWTH ZONE /DGZ/... DECENT OMEGA IN LOW LEVELS AND 
SUFFICIENT DELTA-T FOR LAKE EFFECT SNOW. THE LAKE EFFECT PORTION 
WILL BEGIN WITH A BROAD AREA OF LIGHT LAKE EFFECT AND THEN 
TRANSITION TO A MORE FOCUSED BAND MUCH LATER IN THE EVENT... TOWARD 
SUNDAY AFTERNOON AND EVENING.

THE SYNOPTIC SYSTEM OF INTEREST FOR SATURDAY NIGHT AND SUNDAY IS 
BACK TO ITS NORTHERLY TRACK IN THE 00Z OPERATIONAL MODELS. THE ECMWF 
IS NOW FURTHEST NORTH. THERE IS A CHANCE THE PRECIP AXIS COULD SLIP 
BACK SOUTHWARD A BIT WITH THE 12Z RUN... THUS THE FORECAST 
CONFIDENCE IS STILL MEDIUM. NONETHELESS... I RAISED POPS ACROSS ALL 
OF SOUTHERN WI FOR THIS EVENT.

MOISTURE FROM A CLOSED UPPER LOW OVER THE SOUTHWEST US WILL STREAM 
NORTHEAST ON THE LOW LEVEL JET SATURDAY AND SATURDAY NIGHT. 
MEANWHILE... A DIGGING 500MB SHORTWAVE TROUGH WILL DROP DOWN THROUGH 
THE NORTHERN PLAINS AND MIDWEST... SUPPORTED BY THE RIGHT ENTRANCE 
REGION OF A STRONG UPPER JET OVER THE GREAT LAKES. THE MAIN SURFACE 
LOW WILL TRACK ACROSS SOUTHERN IL DURING THE DAY SUNDAY. LOOK FOR 
SNOW TO SPREAD INTO FAR SOUTHERN WI AHEAD OF THE DEVELOPING SFC LOW 
SATURDAY EVENING. THE SNOW WILL SPREAD FURTHER NORTH LATE SAT 
NIGHT... LIKELY INTO THE NORTHERN MKX FORECAST AREA.

THE COMBINATION OF THE LAKE EFFECT/ENHANCEMENT AND THE SYSTEM SNOW 
WILL LEAD TO SLIGHTLY HIGHER SNOWFALL ACCUM IN FAR SOUTHEAST WI... 
ABOUT AN INCH MORE. THE TOTAL SNOWFALL AMOUNTS AT THIS TIME LOOK 
LIKE THE 2 TO 4 INCH RANGE SOUTH OF A LINE FROM SHEBOYGAN TO THE 
DELLS WITH HIGHEST AMOUNTS IN THE FAR SOUTHEAST. THIS WOULD HAPPEN 
OVER AN EXTENDED PERIOD OF TIME... MAINLY LATE SATURDAY NIGHT 
THROUGH SUNDAY AFTERNOON.

LIGHT LAKE EFFECT SNOW MAY LINGER IN SOUTHEAST WI THROUGH LATE 
SUNDAY NIGHT.

MONDAY THROUGH THURSDAY... FORECAST CONFIDENCE MEDIUM.

NORTHWEST FLOW ALOFT WILL RESUME OVER THE UPPER MIDWEST. CLIPPERS 
COULD BRING LIGHT SNOW TO SOUTHERN WI MONDAY NIGHT... TUE NIGHT AND 
AGAIN WED NIGHT. TEMPS WILL BE SLIGHTLY BELOW NORMAL DURING THIS 
PERIOD.

&&

.AVIATION/12Z TAFS/...

SCATTERED TO BROKEN STRATOCUMULUS AROUND 3 TO 5 THSD FT WITH A FEW 
MVFR CIGS WILL GRADUALLY BECOME SCATTERED OVER MUCH OF SOUTHERN 
WISCONSIN BY NOON.  A BAND OF MID CLOUDS WILL THEN MOVE ACROSS 
SOUTHERN WISCONSIN THIS AFTERNOON. 

&&

.MARINE...

EXPECT THE NORTH TO NORTHWEST WINDS TO SUBSIDE THIS MORNING CAUSING 
WAVES TO DROP BELOW ADVISORY LEVELS BY NOON. 

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL NOON CST TODAY FOR LMZ643>646.

&&

$$

TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SATURDAY THROUGH THURSDAY...MRC

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