000
FXUS63 KGRB 040545
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1145 PM CST MON MAR 3 2014

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 212 PM CST MON MAR 3 2014

LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE STRETCHING FROM TEXAS TO THE CENTRAL GREAT LAKES EARLY
THIS AFTERNOON. CLOUDS ARE INCREASING FROM WEST TO EAST ACROSS THE
STATE AHEAD OF SHORTWAVES MOVING ACROSS THE DAKOTAS. THE LEADING
EDGE OF A BAND OF SNOW IS ALREADY APPROACHING NORTHWEST WISCONSIN
ALONG A MID-LEVEL FGEN/WARM ADVECTION ZONE. DISTANCE/SPEED TOOL
HAS THIS BAND OF SNOW MOVING INTO NORTH-CENTRAL WISCONSIN BETWEEN
23-00Z THIS AFTERNOON. AS THE SNOW MOVES TO THE SOUTHEAST...SNOW
TIMING AND AMOUNTS ARE THE MAIN FORECAST CONCERNS.

TONIGHT...WEAK SHORTWAVE ENERGY OVER THE DAKOTAS WILL MOVE ESE TO THE
NORTHERN MISSISSIPPI VALLEY THIS EVENING AND REACH LAKE MICHIGAN BY
12Z TUESDAY.  AHEAD OF THE WAVES...FORCING IN THE FORM OF ISENTROPIC
ASCENT...700-500MB FGEN AND WEAK UPPER DIVERGENCE WILL PUSH THE AREA
OF SNOW OVER EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA ACROSS
NORTHERN WISCONSIN THIS EVENING.  UNCERTAINTY REMAINS HOW THIS WILL
EVOLVE...BUT SOME MODELS SHOW A SECONDARY AREA OF SNOW MAY ALSO
DEVELOP OVER SOUTHERN MINNESOTA/NORTHERN IOWA THIS EVENING ALONG THE
LOW LEVEL BAROCLINIC ZONE AND THEN MERGE WITH THE PRIMARY AREA OF
SNOW OVER CENTRAL AND EASTERN WISCONSIN.  AS A RESULT...THINK ALL
AREAS WILL SEE DECENT ACCUMULATING SNOW TONIGHT THOUGH PIN POINTING
WHERE AND HOW MUCH SNOW WILL FALL IS RATHER DIFFICULT DUE TO THE
UNORGANIZED FORCING.  ADDING TO THE COMPLEXITY IS A DEEP DENDRITIC
GROWTH ZONE THAT COULD LEAD TO HIGH END SNOW TO LIQUID RATIOS.  BEST
GUESS IS NOT THAT DIFFERENT FROM THE PREVIOUS SHIFT...FROM TOMAHAWK
TO STURGEON BAY WHERE HAVE ABOUT 2 INCHES IN THE FORECAST THROUGH
TONIGHT.  THE SNOW WILL BE LIGHT AND FLUFFY...AND BE WINDING DOWN
TOWARDS THE START OF THE MORNING COMMUTE...SO DO NOT PLAN ON ANY
ADVISORIES.  BUT WILL ISSUE AN SPS TO HIGHLIGHT SLICK ROADS TONIGHT
AND EARLY TOMORROW MORNING.

TUESDAY...LIGHT SNOW WILL BE ONGOING OVER MUCH OF THE FORECAST EARLY
TUESDAY MORNING UNTIL THE SHORTWAVE EXITS TO THE EAST.  BUT EVEN
AFTER THIS TIME...THE MID-LEVEL THERMAL GRADIENT WILL BE OVERHEAD
AND PROGGED SOUNDINGS INDICATE PLENTY OF MOISTURE WILL BE LEFTOVER
THROUGH 700-600MB UNTIL MID TO LATE AFTERNOON.  SO DESPITE THE
SHORTWAVES PULLING OUT...POTENTIAL IS THERE FOR LIGHT SNOW/FLURRIES
TO LINGER INTO THE AFTERNOON.  ADDITIONAL ACCUMS WILL REACH UP TO A
HALF INCH...AND MUCH OF THAT WILL COME EARLY IN THE MORNING.  SKIES
WILL BE MAINLY CLOUDY...BUT HIGHS WILL CONTINUE THERE WARMING TREND
AND REACH THE UPPER TEENS TO LOWER 20S.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 212 PM CST MON MAR 3 2014

CONTINUED NEAR ZONAL-PROGRESSIVE PATTERN OVER THE NORTHERN U.S.
THIS PERIOD. SPREAD SEEN IN MODELS/ENSEMBLES LATER PERIODS WITH HOW
HANDLE ENERGY COMING INTO PACIFIC COAST AND EFFECTS ON UPPER RIDGE.
TRENDS ARE FOR TEMPS TO WARM CLOSER TO NORMS THROUGH PERIOD WITH
MORE WESTERLY FLOW. MODEL BLEND FOR NEXT MONDAY SHOWING UPPER 30S
ATTM. A REAL CONTRAST FROM TODAY.

LIGHT SNOW CHANCES AT ISSUE AGAIN TUE NIGHT AS WEAK WAVE MOVES
THROUGH FLOW. WAA SETS UP OVER BAROCLINIC ZONE TO BE CENTERED OVER
SOUTHERN HALF OF WI. WEAK FGEN/JET SUPPORT...PASSES MAINLY SOUTH
OF CWA. AGAIN MODELS TRENDING TOWARD DEEP DENDRITIC GROWTH ZONE.
HAVE TIGHTENED GRADIENT UP FOR SNOW-NO SNOW WITH HIGH PRESSURE
RIDGING SOUTH OUT OF CANADA INTO NORTHERN WI. KEPT CHANCE POPS
OVER FAR SOUTHERN COUNTIES.

NEXT ISSUE WITH UPPER LOW NOW MOVING INTO BRITISH COLUMBIA.
FEATURE TO TRACK EAST ACROSS CANADA. MODELS SHOWING A BIT BETTER
AGREEMENT WITH FOCUS OF PCPN CHANCES THU OVER NORTHWEST WI AND
NORTHEAST MN...MOVING INTO CWA THU NIGHT INTO FRI WITH COLD FRONT
MOVING THROUGH STATE.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1145 PM CST MON MAR 3 2014

AN AREA OF LIGHT SNOW PASSING OVER THE REGION EARLY
THIS MORNING WILL PRODUCE A PERIOD OF MVFR CIGS AND VSBYS. AROUND
DAYBREAK CIGS WILL THEN IMPROVE TO A MIX OF VFR CIGS WITH
SCATTERED MVFR CIGS AND VSBYS DUE TO SNOW SHOWERS.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......TDH