FXUS63 KMKX 260303
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
903 PM CST FRI DEC 25 2009
.UPDATE...
PRECIPITATION ALL SNOW NOW ACROSS THE FORECAST AREA. ONE BAND OF
ENHANCED IR CLOUDS MOVING ACROSS THE FORECAST AREA. MAINLY LIGHT
SNOW BUT VISIBILITIES DOWN TO NEAR ONE MILE AT TIMES.
ACCUMULATIONS MAINLY AN INCH OR LESS. EXPECT A LULL AFTER THIS
ENHANCED AREA ASSOCIATED WITH PVA LOBE PUSHES NORTH.
NEW 00Z NAM BRINGS UPPER LOW ACROSS NORTHERN ILLINOIS
TONIGHT...AND INTO SOUTHEAST WISCONSIN BY SUNRISE. UPPER LOW MAY
BRING ANOTHER PERIOD OF STEADIER SNOW DURING THE EARLY MORNING HOURS.
&&
HENTZ
.PREV DISCUSSION... /ISSUED 313 PM CST FRI DEC 25 2009/
SHORT TERM...
TONIGHT-
FORECAST CONFIDENCE...HIGH
OCCLUDED FRONT SHOULD CONTINUE SURGING NORTHEAST. EXPECTED TO
REACH MADISON AROUND 4 PM...MILWAUKEE 530 PM...FOND DU LAC 730
PM...AND SHEBOYGAN AROUND 8 PM. TEMPERATURES FALL QUICKLY INTO THE
20S BEHIND THE FRONT WITH SHIFT OF WIND TO SOUTH-SOUTHWEST.
BAND OF PRECIPITATION ALONG OCCLUDED FRONT DOES APPEAR TO CHANGE
TO SNOW BRIEFLY BEFORE ENDING. THERE WILL ALSO BE ADDITIONAL
PERIODS OF LIGHT SNOW DURING THE NIGHT BUT PROBABLY NOTHING MORE
THAN HALF AN INCH MOST AREAS.
THE POTENTIAL FOR A FLASH FREEZE IS OF MORE CONCERN. UNTREATED
SURFACES WILL QUICKLY FREEZE INTO SHEETS OF ICE WITH SOME LIGHT
SNOW ON TOP CREATING HAZARDOUS CONDITIONS. WILL CONTINUE TO
HIGHLIGHT THIS IN A SPECIAL WEATHER STATEMENT.
SATURDAY-
FORECAST CONFIDENCE...MEDIUM
UNUSUAL SITUATION SETTING UP TOMORROW. UPPER LOW WOBBLES WESTWARD
OVER WISCONSIN WITH SURFACE LOW ROTATING EAST ACROSS IOWA TOWARD
NORTHERN ILLINOIS. SO IT LOOKS LIKE A BATCH OF LIGHT SNOW WITH
PERHAPS 1-2 INCHES ACCUMULATION HEADED FOR SOUTHERN WISCONSIN.
SINCE 850 MB TEMPERATURES CRASH TO -10 TO -12C...RATHER UNSTABLE
CONDITIONS DO DEVELOP OVER THE LAKE.
SOUTHERLY FLOW REGIME AHEAD OF LOW COULD DEVELOP A RARE SOUTH TO
NORTH PRIMARY LAKE BAND...WHICH THEN IS SHOWN BY NAM AND LOCAL
MESOSCALE MODELS TO PIVOT NORTHWEST TOWARD EAST CENTRAL WISCONSIN
SATURDAY AFTERNOON AND EVENING. NAM BUFKIT SOUNDING FOR KSBM IS
VERY IMPRESSIVE...WITH ABOUT 500 J/KG OF LAKE INDUCED CAPE.
VARIOUS MODELS PRODUCE 0.25 TO 0.50 INCH OF LIQUID QPF WITH
THIS...MAINLY JUST NORTH OF CWA IN MANITOWOC COUNTY.
COORDINATED WITH GREEN BAY OFFICE ON THIS AND HAVE POTENTIAL FOR 4
TO 6 INCHES OF SNOW ON SHEBOYGAN SHORE. THUS MAY HAVE TO CONSIDER
A SNOW ADVISORY OR LAKE SNOW ADVISORY IN LATER PACKAGES.
SUNDAY-
FORECAST CONFIDENCE...HIGH
UPPER LOW CONTINUES LARGE CYCLOIDAL MOTION AND TURNS BACK TO THE
SOUTHEAST TOWARD NORTHERN INDIANA BY EVENING. DEEP CYCLONIC FLOW
OVER AREA SHOULD CONTINUE THREAT FOR SNOW SHOWERS.
ALL TOLD...OVER A 48 HOUR PERIOD FROM TONIGHT THROUGH SUNDAY...MANY
AREAS COULD SEE 2 TO 4 INCHES OF SNOW WITH EXCEPTION OF LAKE
EFFECT POTENTIAL. GIVEN THE LONG DURATION OF THE EVENT...WINTER
WEATHER ADVISORIES ARE NOT ANTICIPATED AWAY FROM THE LAKE.
MONDAY-
FORECAST CONFIDENCE...MEDIUM
SIGNIFICANT HEIGHT RISE OCCUR BUT CYCLONIC NORTHWEST FLOW
CONTINUES. AT THIS TIME LEAVING OUT PRECIPITATION...BUT FLURRIES
NOT OUT OF THE QUESTION BUT MORE LIKELY NORTH AND EAST OF SOUTHERN
WISCONSIN.
LONG TERM...
TUESDAY-
FORECAST CONFIDENCE...HIGH
QUIET WEATHER EXPECTED WITH HIGH PRESSURE RIDGE BOTH SURFACE AND
ALOFT.
WEDNESDAY-
FORECAST CONFIDENCE...MEDIUM
NEXT WEAK TROUGH MOVES INTO AREA WITH LIGHT SNOWS POSSIBLE. COULD
END UP BEING AN INCH OR TWO BUT NOT PLAYING THIS UP MUCH YET.
THURSDAY AND FRIDAY-
FORECAST CONFIDENCE...LOW
12Z ECMWF AND GFS DIFFERENCES BECOME MORE APPARENT. BOTH HAVE A
LONG WAVE TROUGH OVER THE CENTRAL STATES...BUT ECMWF HAS A DEEPER
UPPER LOW MOVING ACROSS MIDDLE MISSISSIPPI VALLEY BY FRIDAY. NOT A
LOT OF MOISTURE SO WILL KEEP SNOW CHANCES RATHER LOW.
AVIATION...
ANOTHER SURGE OF RAIN HEADING NNW INTO THE CWA FROM IL
ASSOCIATED WITH NEXT PIECE OF ENERGY WRAPPING AROUND MASSIVE UPPER
LOW. COLD FRONT KNOCKING ON THE DOOR FROM THE SOUTHWEST...WILL
CHANGE LIGHT RAIN TO LIGHT SNOW AS THERMAL PROFILE COOLS. EXPECTING
IFR CEILINGS TO BECOME PREDOMINANTLY MVFR AS THE NIGHT WEARS ON. THE
UPPER LOW IS EXPECTED TO WOBBLE ACROSS THE STATE LATER TONIGHT
THROUGH THE WEEKEND.
MARINE...
GRADIENT EXPECTED TO WEAKEN A BIT TONIGHT. WINDS TO SHIFT
TO THE SOUTH WITH FROPA. WILL TRANSITION TO SMALL CRAFT ADVISORY FOR
LINGERING GUSTY SOUTHEAST WINDS SHIFTING SOUTH. WILL TAKE SOME TIME
FOR WAVES TO SETTLE DOWN. WITH SURFACE LOW BECOMING SITUATED ACROSS
SOUTHERN WI AND NORTHERN IL SATURDAY...EXPECT LIGHTER WIND REGIME TO
BE IN PLACE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM CST SATURDAY FOR LMZ643>646.
&&
$$
SHORT/LONG TERM...CRAVEN/02
AVIATION/MARINE...COLLAR/10
