000
FXUS63 KMKX 250924
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
324 AM CST FRI FEB 25 2011
.TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
NORTH TO NORTHEAST WINDS WILL PROVIDE A GOOD FETCH FOR POSSIBLE LAKE
ENHANCEMENT...BUT WITH BARELY BORDERLINE SFC TO 850 DELTA T VALUES
AROUND 10C DON'T EXPECT ANYTHING ORGANIZED. STILL A FEW LINGERING
LIGHT SNOW OR FLURRIES OVER THE FAR SOUTHEAST TIP AT THE START OF
THE FORECAST PERIOD...BUT THIS WILL QUICKLY END.
THEN 700 MB WARM AIR ADVECTION BRINGS WEAK ISENTROPIC LIFT WITH
CONDENSATION PRESSURE DEFICITS AROUND 14 MB. THIS COMBINED WITH A
WEAK VORT MAX MOVING ACROSS THE REGION THIS AFTERNOON WILL BRING A
CHANCE OF LIGHT SNOW.
850 TO 700 MB MOISTURE...WEAK Q VECTOR CONVERGENCE AND SOME
FAVORABLE SATURATED EQUIVALENT POTENTIAL VORTICITY MAY BRING ANOTHER
CHANCE OF LIGHT SNOW TONIGHT.
SATURDAY- CONFIDENCE...MEDIUM
HIGH PRESSURE IN CONTROL AT THE SURFACE...HOWEVER IN THE MID AND
UPPER LEVELS...STRONG JET MAX AT 200-300 MILLIBARS WILL BE ACROSS
THE CWA...WITH SOME HINT OF SOME RIGHT REAR DIVERGENCE. LOW LEVEL
ISENTROPIC LIFT WILL BE WEAK THOUGH FAIRLY PERSISTENT. WITH MOST
MODELS GENERATING 0.05 TO 0.10 LIQUID...WILL BOOST THE GOING POPS TO
LIKELY. HPC GENERATES THE LOWEST QPF WHILE THE CANADIAN HAS UP TO
0.20 INCHES. WILL STEER TOWARDS THE MIDDLE GROUND.
SUNDAY- CONFIDENCE...MEDIUM
280-290K ISENTROPIC PLOTS SHOW WEAK UPGLIDE UNDERWAY IN ADVANCE OF
THE APPROACHING STORM SYSTEM. NAM PLOTS LOOK MORE REASONABLE THAN
THE GFS. THE CONDENSATION PRESSURE DEFICITS ARE A BIT HIGH BUT SOME
LIGHT PRECIP NOT OUT OF THE QUESTION. PRETTY DECENT 850 WARM SURGE
AS READINGS GO FROM -3/-4C TO 5/6C BY 00Z MONDAY. THE GFS HAS
EXTENSIVE LIGHT QPF WHILE THE NAM AND ECMWF ARE DRY. WILL CONFINE
POPS TO THE AFTERNOON AND KEEP THEM IN THE SLIGHT CHANCE CATEGORY.
SUNDAY NIGHT- CONFIDENCE...MEDIUM
850 LOW MOVES ACROSS SOUTHEAST WI. EXTENSIVE QPF WITH SOME UPPER JET
COUPLING NOTED. THE WARM SURGE ON EASTERN SIDE OF 850 LOW SHOVES
BAROCLINIC ZONE/0C ISOTHERM OUT OF CWA...PRETTY GOOD SHOT WHOLE AREA
WILL BE LIQUID BETWEEN 00-06Z MONDAY. PRETTY DECENT MID LEVEL LAPSE
RATES AND NEGATIVE SHOWALTER VALUES SUPPORTS THE GOING MENTION OF
THUNDER. WHEN LOW SHIFTS TO THE EAST...COLDER AIR WRAPS IN ON THE
BACK SIDE WITH COLLAPSING 850 TEMPS/1000-500 MILLIBAR THICKNESSES.
WILL LIKELY BE A TRANSITION OF RAIN TO SNOW...ESPECIALLY IN
NORTHWEST CWA. BY THE TIME THE COLDER AIR ARRIVES INTO THE
SOUTHEAST...MUCH OF THE MOISTURE AND LIFT WILL HAVE SHIFTED AWAY.
MONDAY- CONFIDENCE...MEDIUM
LOW PULLS AWAY RATHER QUICKLY DURING THE MORNING. MODELS KEEP LIGHT
QPF AROUND FOR A TIME IN THE SOUTHEAST CWA...THIS WOULD BE ALL LIGHT
SNOW WITH THE COLDER TEMPERATURE REGIME IN PLACE. SHORTWAVE RIDGING
BUILDS IN QUICKLY FOR THE AFTERNOON.
TUESDAY AND WEDNESDAY- CONFIDENCE...LOW
BRIEF 850 THERMAL RIDGE ON TUESDAY AHEAD OF A LOW TRAVERSING NEAR
LAKE SUPERIOR. MOISTURE/LIFT TIED TO THE STRONGER DYNAMICS TO THE
NORTH. COLD ADVECTION THEN KICKS IN FOR LATER TUESDAY INTO TUESDAY
EVENING. BIG DIFFERENCE IN 850 TEMP REGIME IN THE COLD ADVECTION
PATTERN. GFS MORE PROGRESSIVE WITH WARM ADVECTION KICKING IN BEHIND
WITH READINGS RANGING FROM -15C ON THE ECMWF TO -5C ON THE GFS.
CANADIAN SUPPORTING THE COLDER LOOK OF THE ECMWF.
THURSDAY- CONFIDENCE...LOW
GFS QUICKER ON BRINGING IN WAA PRECIP FOR THURSDAY WHILE ECMWF HOLDS
THIS OFF UNTIL THURSDAY NIGHT. BETTER CONSENSUS FOR POPS ON THURSDAY
NIGHT...AND WITH THE SLOWER LOOK OF THE CANADIAN...SEEMS BETTER TO
HAVE SLIGHTLY HIGHER POPS THURSDAY NIGHT THAN ON THURSDAY.
&&
.AVIATION...SOME MVFR CIGS WITH NORTHEAST FLOW OFF LAKE MICHIGAN.
NORTH TO NORTHEAST WINDS WILL PROVIDE A GOOD FETCH FOR POSSIBLE
LAKE ENHANCEMENT...BUT WITH BARELY BORDERLINE SFC TO 850 DELTA T
VALUES AROUND 10C DON'T EXPECT ANYTHING ORGANIZED. A FEW LINGERING
AREAS OF LIGHT SNOW OR FLURRIES WITH MVFR VSBYS OVER THE FAR
SOUTHEAST TIP AT THE START OF THE FORECAST PERIOD...BUT THIS WILL
QUICKLY END AS MAIN LOW OVER NORTHEAST KENTUCKY MOVES OFF.
THEN 700 MB WARM AIR ADVECTION BRINGS WEAK ISENTROPIC LIFT WITH
CONDENSATION PRESSURE DEFICITS AROUND 14 MB. THIS COMBINED WITH A
WEAK VORT MAX MOVING ACROSS THE REGION THIS AFTERNOON WILL BRING A
CHANCE OF LIGHT SNOW. SOME MVFR CIGS AND VSBYS IN LIGHT SNOW WITH
THIS.
AS MOIST AIR RETURNS EXPECT MORE MVFR CIGS AND SOME LIGHT SNOW
POSSIBILITIES TONIGHT.
&&
.MARINE...SMALL CRAFT CONDITIONS WILL CONTINUE TODAY AS NORTH TO
NORTHEAST WINDS OF 15 TO 25 KNOTS CONTINUE. WINDS WILL DIMINISH
THIS AFTERNOON...BUT HIGHER WAVES WILL LINGER A BIT LONGER. THUS
KEPT SMALL CRAFT ADVISORY GOING INTO EARLY FRIDAY EVENING. THIS MAY
BE ABLE TO BE CANCELLED EARLY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
SHORT/LONG TERM...COLLAR
TODAY/TONIGHT/AVIATION/MARINE...HENTZ
