FXUS63 KGRB 250948
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
348 AM CST FRI DEC 25 2009

.SHORT TERM...TODAY/TONIGHT/SATURDAY. CHALLENGE DURING THIS XMAS PERIOD
IS DEALING WITH THE AN UPPER LOW GUEST WHO WONT LEAVE. SYSTEM WILL
CONTINUE TO THROW VARIOUS WEATHER CHALLENGES THROUGH
SATURDAY...BUT THE CONTINUED LONG DURATION WARNING HEADLINE IS NO
LONGER SUPPORTED AFTER CALLS TO THE COUNTIES.  REEVALUATED AND
COORDINATED HEADLINES WITH ADJACENT OFFICES THIS MORNING AFTER
OBSERVING CURRENT CONDITIONS AND ANTICIPATED CONDITIONS TODAY.
THIS DOES NOT MEAN ADDITIONAL HEADLINES WILL NOT BE NEEDED THROUGH
SATURDAY JUST NOT THE PRECIOUS ONES. WARM AIR ALOFT ON SE WINDS
CONTINUES WORKING OVER THE AREA THIS MORNING. AT 09Z...PCPN HAS
TURNED TO MAINLY RAIN MIXED WITH SLEET AT TIMES OVER EC WI...THEN
A MIX OF R/ZR/IP/S OVER CENTRAL AND NORTH CENTRAL...BUT MAINLY
RAIN ACCORDING TO COUNTIES.  LIGHT SNOW MAY BE THE DOMINATE PCPN
TYPE FOR A FEW HOURS THIS MORNING OVER FAR NC WI. NEVERTHELESS
WARNING CRITERIA NO LONGER BEING MET SO WILL CHANGE TO AN ADVISORY
FOR THE MIX OVER CENTRAL AND NORTH CENTRAL WI AND LET THE EC WI
ADVISORY EXPIRE AT 4 AM.  UNTREATED ROADS AND SECONDARY ROADS
LIKELY NOT IN GOOD SHAPE FROM PCPN THE LAST FEW DAYS...BUT EXPECT
SOME IMPROVEMENT THIS MORNING AS TEMPS CONTINUE TO RISE INTO THE
30S FROM EAST TO WEST.

PROGS AND FORECAST SOUNDINGS INDICATE THE WARMING TREND ENDS THIS
AFTERNOON AS THE OCCLUDED FRONT WITH CAA FROM THE SOUTH ALONG WITH
DRYING PRODUCING EVAP COOLING BEGINS TURNS THE PCPN TYPE OVER TO
SNOW AGAIN. QUESTION IS HOW FAST. THIS TRANSITION PERIOD OCCURS
MAINLY AFTER PREVIOUS HEADLINES AND ITS QUITE POSSIBLE PARTS OF
NC WI AND FAR NE WI MAY NEED ADDITIONAL ADVISORY HEADLINES FOR
SNOW AS THIS UPPER LOW PIVOTS OVER THE AREA. WILL ACCOUNT FOR THE
ADDITIONAL SNOW TONIGHT OVER THE NORTH BY LINGERING THE ADVISORY
TIL 9 PM. OTHERWISE WILL CONTINUE WITH THE TREND OF THE RAIN OR
RAIN MIX TURNING BACK OVER TO SNOW BY EARLY EVENING. MORE OF A
PROBLEM FOR TONIGHT IS THE POTENTIAL OF A FLASH FREEZE OVERNIGHT
AS TEMPERATURES DROP INTO THE LOWER TO MID 20S OVERNIGHT OVER THE
WET ROADS.  LATER SHIFTS MAY NEED TO ADDRESS WITH A SPS.

SYSTEM CONTINUES TO STACK AND SLOWLY WEAKEN BUT WILL CONTINUE TO
PRODUCE LIGHT SNOW THROUGH SATURDAY. ACCUMULATING SNOW EXPECTED
TO BE MINOR OR NON ADVISORY TYPE AT THIS TIME.

FORECAST MAX TEMPS TO BE REACHED EARLY AFTERNOON BEFORE STALLING
PRIOR TO OCCLUDED FRONT FROM THE SOUTH THEN FALL OVERNIGHT.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY.

TIMING THE DEPARTURE OF THE CURRENT STORM SYSTEM IS THE MAIN
CONCERN DURING THIS PART OF THE FORECAST.

MEDIUM RANGE MODELS APPEARED TO BE INDICATING SOME DRY AIR WRAPPED
AROUND THE BACK SIDE OF THE DEPARTING SYSTEM...INTO NORTHERN
WISCONSIN FOR SATURDAY NIGHT. HAVE CHANCE POPS IN THE NORTH WITH
LIKELY POPS FOR THE REST OF THE CWA AS A RESULT OF THIS. POPS
DECREASE TO CHANCE ON SUNDAY AS THE SURFACE LOW BECOMES MORE
DIFFICULT TO EVEN IDENTIFY. FOR SUNDAY NIGHT THERE WILL ONLY BE
SOME SCATTERED OR ISOLATED LIGHT SNOW SHOWERS IN NORTH-CENTRAL
WISCONSIN AND THE DOOR PENINSULA SINCE NORTHERLY FLOW OVER THE WARMER
WATERS COULD BRING SOME LAKE EFFECT TO THOSE LOCATIONS. OTHERWISE
JUST WENT WITH A CHANCE OF FLURRIES. ONLY A SLIGHT CHANCE OF SNOW
ON MONDAY FOR LOCATIONS SUSCEPTIBLE TO LAKE EFFECT. DID NOT MENTION
SNOW ANYWHERE ELSE IN THE CWA.

HAVE A DRY PERIOD IN THE FORECAST FOR MONDAY NIGHT THROUGH TUESDAY
NIGHT AS A SURFACE HIGH AND WEAK UPPER RIDGE PASS THROUGH THE REGION.

DID NOT MAKE MAJOR CHANGES TO TEMPERATURES IN THE LONG TERM. THE
EARLY PART OF NEXT WEEK LOOKS TO BE RATHER COLD WITH RECENT
SNOWFALL AND PLENTY OF BREAKS IN THE CLOUDS DURING THE NIGHTS. IF
LATER MODEL RUNS INDICATE CLEAR SKIES AND LIGHT WINDS...TEMPERATURES
WILL PROBABLY NEED TO BE LOWERED FROM THEIR CURRENT FORECAST
VALUES.
&&

.AVIATION...WIDESPREAD IFR CIGS AND MVFR VSBYS EXPECTED TODAY AND
TONIGHT. PCPN WILL BECOME MAINLY RAIN OVER EC WI TODAY...BUT TURN
BACK OVER TO SNOW TONIGHT. OVER CENTRAL AND NORTH CENTRAL WI...A
MIX OF SNOW...FREEZING RAIN...RAIN AND SLEET WILL CONTINUE TODAY
THEN TURN OVER TO ALL SNOW TONIGHT.
&&

.MARINE...WILL CONTINUE GALE WARNING FOR THE NEARSHORE. AS THE
SURFACE LOW SHIFTS NORTH LATE TODAY INTO THIS EVENING...WINDS WILL
DIMINISH. LATER SHIFTS CAN ADJUST TO THE SMALL CRAFT ADVISORY
TOWARD TONIGHT AFTER THE GALE WARNING EXPIRES.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ005-
010>013-018-019.

WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ020-
021-030-031-035>037-045.

&&

$$
TDH/MG