000
FXUS63 KMKX 010254
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
854 PM CST SAT FEB 28 2015

.UPDATE...

NEW 00Z MODELS AND HIGH RES MESO MODELS ARE KEEPING THE LIGHT SNOW
MAINLY SOUTH OF THE BORDER...ALTHOUGH THE MESO MODELS DO HAVE SOME
WEAK REFLECTIVITY`S ON THE SIMULATED RADAR PRODUCTS. 00Z MODELS
MAY HAVE BACKED OFF TOO MUCH AS A FEW SITES ARE REPORTING LIGHT
SNOW IN THE ILLINOIS BORDER COUNTIES AND RACINE. THIS WILL BE
SHORT LIVED AS THE VERY LIGHT PRECIPITATION MOVES QUICKLY EAST AS
THE LEFT EXIT REGION OF THE 250 MB 145 KNOT JET MAX MOVES EAST.

&&

.AVIATION/06Z TAFS/...

SOME MVFR VSBYS IN SNOW IN THE ILLINOIS BORDER COUNTIES AND
RACINE. VERY LIGHT SNOW MAY REACH THE MILWAUKEE AREA. THIS WILL BE
SHORT LIVED AS THE VERY LIGHT PRECIPITATION MOVES QUICKLY EAST
EARLY THIS MORNING AS THE LEFT EXIT REGION OF THE 250 MB 145 KNOT
JET MAX MOVES EAST.

MAINLY VFR CIGS...THEN A PERIOD OF MVFR CIGS EXPECTED SUNDAY AS A
WEAK SURFACE TROUGH APPROACHES.

&&

.PREV DISCUSSION... /ISSUED 235 PM CST SAT FEB 28 2015/

TONIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.

MIDDLE TO LOW LEVEL CLOUDS FROM THE SOUTHWEST WILL SHIFT INTO THE
AREA INTO THE EARLY EVENING HOURS.

MAINLY VERY LIGHT SNOW SHOULD AFFECT THE FAR SOUTHEAST COUNTIES FROM
MIDDLE EVENING INTO THE OVERNIGHT HOURS...AS WARM AIR ADVECTION AND
A MODEST 500 MB VORTICITY MAXIMUM PUSHES INTO THE AREA. UPWARD
VERTICAL MOTION FIELDS ARE RATHER WEAK OVER THE SOUTHEAST
COUNTIES...WITH THE STRONGER UPWARD MOTION REMAINING JUST TO THE
SOUTH.

SYNOPTIC MODELS SHOWING LIGHT QPF IN THE SOUTHERN COUNTIES THIS
EVENING...THOUGH MESOSCALE MODELS JUST CLIPPING THE FAR SOUTHEAST
COUNTIES WITH LIGHT SIMULATED REFLECTIVITIES. IN FACT...THE HRRR
KEEPS ALL OF THIS ACTIVITY SOUTHEAST OF THE AREA. SOME UNCERTAINTY
HERE WITH POPS AS A RESULT.

AREA FORECAST SOUNDINGS DO SHOW LOW TO MID LEVEL SATURATION IN
FAIRLY DEEP DENDRITE SNOW GROWTH ZONE FROM AROUND 03Z TO 08Z SUNDAY.
FOR NOW...ADJUSTED POPS UPWARD IN THE FAR SOUTHEAST PORTIONS OF THE
AREA DURING THIS TIME. ANY SNOW ACCUMULATIONS WILL BE VERY LIGHT...A
TENTH OF AN INCH OR SO AT WORST. SHOULD SEE SCATTERED FLURRIES
ELSEWHERE ACROSS THE AREA.

SOME LINGERING LOW LEVEL MOISTURE AND STEEP LOW LEVEL LAPSE RATES
SUNDAY...ALONG WITH APPROACHING STRONG SHORTWAVE TROUGH LATER IN THE
DAY...SHOULD SUPPORT MORE FLURRIES. MILDER...BUT STILL BELOW NORMAL
TEMPERATURES...ARE EXPECTED TONIGHT AND SUNDAY.

SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE IS HIGH.

LOOK FOR COLD AIR TO ADVECT IN SUNDAY NIGHT IN THE WAKE OF A
DEPARTING COLD FRONT. SKIES SHOULD GRADUALLY CLEAR FROM WEST TO
EAST...BUT THE PERSISTENT WEST TO NORTHWEST WIND SHOULD KEEP TEMPS
FROM BOTTOMING OUT TOO HARD. STILL...LOWS WILL DIP INTO THE 7 TO
13 ABOVE RANGE. FULL SUNSHINE AND LIGHT WINDS WITH HIGH PRESSURE
MOVING OVERHEAD ON MONDAY WILL ALLOW TEMPS TO RECOVER INTO THE MID
20S.

MONDAY NIGHT INTO TUESDAY EVENING...FORECAST CONFIDENCE IS
MEDIUM.

NO MAJOR SURPRISES WITH THE SYSTEM COMING IN PRIMARILY AFTER
SUNRISE ON TUESDAY. THE MODELS ARE IN RATHER GOOD AGREEMENT FOR A
SYSTEM THIS FAR OUT. THE TOUGH DETAILS CONTINUE TO BE WHERE THE
PRECIP TRANSITION LINE WILL SET UP ON TUESDAY. SNOW SHOULD BEGIN
TO SPREAD IN LATER MONDAY NIGHT AS STRONG WARM AIR ADVECTION
ARRIVES AHEAD OF A DEEPENING TROF OVER THE CENTRAL PLAINS. THE
THE MOISTURE SURGE AND DEEPEST FORCING PEAKS FROM TUESDAY MORNING
THROUGH MID AFTERNOON ON TUESDAY. THE MORNING RUSH HOUR COULD GET
DICEY.

THE BIG QUESTION IS HOW FAR NORTH THE WARM LAYER WILL GET...RESULTING
IN A WINTRY MIX POTENTIAL WITH THE POTENTIAL FOR SOME FREEZING
RAIN.  THE GFS OPERATIONAL RUN IS ONE OF THE MOST BULLISH
SOLUTIONS...PUSHING IT INTO THE SOUTHERN HALF OF THE FORECAST
AREA. THE GFS ENSEMBLE MEAN KEEPS THAT LAYER ALONG THE STATE LINE
AND SOUTH. THE ECMWF SUGGESTS AN ALL SNOW SOLUTION FOR OUR
AREA...AS DOES THE CANADIAN AND THE NAM.

THE LATEST SREF INDICATES A VERY SMALL POTENTIAL FOR A MIX ACROSS
THE FAR SOUTHERN TIER...BUT A MUCH BETTER CHANCE FOR ALL SNOW.
MOST OF THE THERMAL PARAMETERS SUPPORT A SNOW EVENT.

GIVEN THAT WE WILL BE STARTING OUT IN A COLD AND DRY AIRMASS...THE
EVAPORATIVE COOLING AND PRECIP RATES SHOULD FAVOR A COLDER
SOLUTION THAN WHAT THE GFS INDICATES. I/LL CONTINUE TO PUT A MIX
IN THE FAR SOUTH...JUST NOT AS FAR NORTH AS THE GFS INDICATES.

WHERE WE SEE SNOW...IT COULD BE A 4 TO 5 INCH SNOWFALL. PLENTY OF
UNCERTAINTY WITH THE LOW TRACK AND THE TEMP PROFILE...SO STAY
TUNED. IT/S A FAST MOVING SYSTEM...AND THAT WILL HELP KEEP THE
SNOWFALL AMOUNTS LOWER.

LOOK FOR THE PRECIP TO TRANSITION BACK TO ALL SNOW AND END QUICKLY
FROM WEST TO EAST DURING THE EARLY EVENING.

WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE IS HIGH.

THE REMAINDER OF THE WEEK LOOKS DRY. IN THE WAKE OF THE DEPARTING
LOW...ANOTHER SHOT OF ARCTIC AIR WILL BRING VERY COLD TEMPERATURES
FOR WEDNESDAY THROUGH THURSDAY NIGHT. HIGHS IN TEENS...LOWS IN THE
SINGLE DIGITS ABOVE/BELOW ZERO. TEMPS REBOUND BY FRIDAY WITH HIGHS
IN THE MID 30S...CONTINUING INTO THE WEEKEND. THOSE TEMPS
WEDNESDAY AND THURSDAY MAY BE THE LAST TIME WE SEE READINGS THIS
COLD THIS SEASON. THE PATTERN BEGINS TO SHIFT TOWARD A
MILDER...MORE NORMAL CONFIGURATION.

AVIATION/00Z TAFS/...

VFR CONDITIONS ARE EXPECTED INTO MID EVENING ACROSS TAF SITES. LIGHT
SOUTH WINDS ARE EXPECTED...AS MIDDLE TO LOW LEVEL CLOUDS PUSH INTO
THE AREA FROM THE SOUTHWEST.

SHOULD SEE A PERIOD OF VERY LIGHT SNOW AFFECT KENOSHA AND PERHAPS
MILWAUKEE AND WAUKESHA FROM ABOUT 03Z TO 08Z SUNDAY. MVFR CEILINGS
ARE EXPECTED BY MIDDLE EVENING...LINGERING INTO SUNDAY. MVFR
VISIBILITIES ARE POSSIBLE AT KENOSHA. MADISON SHOULD SEE
JUST FLURRIES.

ANY SNOW ACCUMULATIONS AT KENOSHA WILL BE VERY LIGHT...A TENTH OF AN
INCH OR SO AT WORST. MILWAUKEE MAY SEE A DUSTING...THOUGH LESS
CONFIDENT THERE. LIGHT SOUTHWEST WINDS LATER TONIGHT WILL INCREASE
SOMEWHAT IN MAGNITUDE ON SUNDAY. FLURRIES WILL LINGER THROUGH SUNDAY
AT ALL SITES...WITH APPROACH OF TROUGH OF LOW PRESSURE FROM THE
NORTHWEST.

&&

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

$$

UPDATE...HENTZ
TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD
SUNDAY NIGHT THROUGH SATURDAY...DAVIS