FXUS63 KMKX 032127 CCA
AFDMKX
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
328 PM CST THU DEC 3 2009
FORECAST FOCUS SQUARELY ON SNOW TONIGHT.
.SHORT TERM/TONIGHT THROUGH SUNDAY/...
.TONIGHT...CONFIDENCE: MEDIUM.
WINTER WEATHER ADVISORY STILL IN EFFECT AS INDIVIDUAL CONVECTIVE
CELLS DEVELOPING OVER SWRN WI EXPECTED TO FORM INTO A NARROW BAND
ALONG SURFACE CONVERGENCE LINE/WIND SHIFT AS INSTABILITY EVIDENT
IN HIGH RESOLUTION MODELS...NAM 12 AND LOCAL WRF...850-700MB QPV
FORECASTS MOVES ACROSS CWA. QPF FROM THESE MODELS PRODUCE UP TO .30
INCH BY CAPTURING THIS CONVECTION THAT LOWER RESOLUTION MODELS
AVERAGE ACROSS A LARGER GRID. SNOW RATIOS WILL GO FROM AROUND 12:1
TO 13:1 TO NEAR 17:1 AS COLDER AIR WORKS INTO THE REGION.
THE MADISON AREA IS ALREADY GETTING INTO THE HEAVIER SNOW BURSTS FOR
THE EVENING RUSH...WITH MKE SEEING THE SNOW TOWARDS THE END OF THE
RUSH. AXIS OF 3-5 INCH SNOWS LOOKS TO SET UP BETWEEN THE I-94
CORRIDOR AND THE ILLINOIS BORDER ROUGHLY FROM LONE ROCK TO KENOSHA.
THERE WILL BE A VERY SHARP CUT-OFF AWAY FROM THIS AXIS. TRYING TO
MARK THE EXACT LOCATION OF THE HEAVY BAND IS WHY CONFIDENCE IS NOT
HIGH.
SNOW WILL DROP OFF RAPIDLY AFTER MIDNIGHT WITH EXIT OF VORT MAX.
CLOUD COVER WILL HOLD LOW TEMPS IN THE UPPER TEENS TO LOWER 20S.
.FRIDAY INTO SUNDAY...CONFIDENCE: HIGH.
FORCING WITH NEXT SHORT WAVE MOVING THROUGH CYCLONIC FLOW WILL STAY
TO THE NORTH OF CWA...BUT LOW LEVEL INSTABILITY WILL BRING SCATTERED
FLURRIES INTO FRIDAY EVENING. NOT MUCH OF A DIURNAL RISE FOR FRIDAY
HIGHS AS COLD AIR ADVECTION CONTINUES THROUGH THE DAY WITH MOSTLY
CLOUDY SKIES WITH MOISTURE TRAPPED UNDER SUBSIDENCE INVERSION.
HIGH PRESSURE KEEPS MOST OF THE WEEKEND DRY. WARM AIR ADVECTION
AHEAD OF NEXT WAVE BEGINS SATURDAY...WITH CLOUDS GRADUALLY BREAKING
FROM SW TO NE. TEMPS WILL CLIMB BACK INTO THE LOW 30S WHICH IS STILL
BELOW NORMAL. TEMPS GET CLOSE TO NORMAL ON SUNDAY...WITH INCREASING
CLOUDS LATE IN THE DAY FROM APPROACHING WAVE.
.LONG TERM/SUNDAY NIGHT THROUGH THURSDAY/...
.SUNDAY NIGHT/MONDAY...CONFIDENCE: MEDIUM.
HIGH CHANCE POPS WARRANTED AS SHORT WAVE AND ASSOCIATED SFC/850 MB
FEATURES MOVE NE ALONG BAROCLINIC ZONE. CURRENT FORECASTED TRACK
PLACES BETTER SNOW AMOUNTS IN NRN CWA...SRN GRB CWA AND TAPERING OFF
TO THE SOUTH...BUT AMOUNTS THRU THE PERIOD LOOK TO TOTAL 1-2 INCHES
AT THIS POINT.
.MONDAY NIGHT INTO TUESDAY...CONFIDENCE: MEDIUM.
HIGH PRESSURE NOSES INTO REGION BETWEEN DEPARTING LOW AND NEXT LOW
DEVELOPING OVER THE SRN PLAINS MONDAY NIGHT. OFFSHORE FLOW WILL
PREVENT ANY LAKE-EFFECT. SHOULD SEE AN INCREASE IN CLOUDS DURING
THE MORNING HOURS TUESDAY.
.TUESDAY AFTERNOON THROUGH WEDNESDAY...CONFIDENCE: LOW.
WITH BOTH GFS AND ECMWF TAKING DEEP SFC LOW TO THE SE THROUGH THE
OHIO RIVER VALLEY...WITH SRN WI TO BE ON INITIALLY ON NRN PERIPHERY
OF PCPN SHIELD AND EVENTUALLY ON WESTERN EDGE. HOWEVER...WILL HAVE
TO BE WATCHED AS MID RANGE MODELS TEND TO TAKE SYSTEMS WELL TO THE
SE...THEN BRING BACK TO THE NW AS AFFECTED TIME PERIOD DRAWS NEAR.
.WEDNESDAY NIGHT AND THURSDAY...CONFIDENCE: MEDIUM.
BASED ON CURRENT TRENDS...SNOW WILL BE ENDING FROM SW TO NE
WEDNESDAY AFTERNOON...WITH DRY WEATHER WEDNESDAY NIGHT AND THURSDAY
AND BELOW NORMAL TEMPERATURES AS HIGH BUILDS IN.
&&
.AVIATION...EXPECT PREVAILING MVFR CIGS THIS EVENING AND TONIGHT AS
AN UPPER LEVEL TROUGH SWINGS THROUGH THE STATE. CONVECTIVE SNOW
SHOWERS CONTINUE TO DEVELOP THIS AFTERNOON AND WILL LAST THROUGH THE
EVENING. THE CURRENT NATURE OF THESE SHOWERS WILL CAUSE VISIBILITIES
TO JUMP ALL OVER THE PLACE...WITH GENERALLY PREVAILING VFR AND
HEAVIER SHOWERS TAKING VISBYS BRIEFLY DOWN TO IFR OR LIFR. THINK
SNOW ACTIVITY WILL BECOME MORE WIDESPREAD THIS EVENING...WITH MVFR
VISBYS PREVAILING AND A CONTINUED THREAT FOR LIFR OR LIFR IN HEAVIER
SHOWERS/BANDS. CIGS WILL ALSO LIKELY DROP TO IFR WITHIN THE HEAVIER
SNOW. THE SNOW WILL GENERALLY WIND DOWN BETWEEN 03Z AND 06Z FROM
WEST TO EAST ACROSS THE FORECAST AREA.
CIGS WILL GENERALLY IMPROVE LATER TONIGHT AS THE LOW MOVES
EAST...BECOMING BORDERLINE VFR/MVFR TOMORROW MORNING AND THROUGH THE
DAY. EXPECT SCATTERED FLURRIES THROUGH THE DAY FRIDAY....ALONG WITH
BREEZY WESTERLY WINDS.
&&
.MARINE...WINDS DECREASED QUITE A WHILE AGO AND HAVE BEEN LIGHTER
THROUGH THE DAY...WITH WAVES SUBSIDING THROUGH THE DAY. GIVEN HOW
LONG AGO THE WINDS DECREASED ALONG WITH A LOOK AT CURRENT LAKE SHORE
WEBCAMS...IT IS LIKELY THAT WAVES ARE NOW GENERALLY FOUR OR LESS
FEET. THEREFORE THE SMALL CRAFT ADVISORY HAS BEEN ALLOWED TO EXPIRE.
WAVES OF 2 TO 4 FEET EARLY THIS EVENING WILL DECREASE TO 1 TO 3 FEET
OVERNIGHT.
THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN AGAIN FRIDAY AND FRIDAY
NIGHT...WITH WINDS AND WAVES APPROACHING SMALL CRAFT ADVISORY
LEVELS. THIS IS WILL BE A WEST TO SOUTHWEST FLOW WHICH MAKES IT MORE
MARGINAL FOR HAZARDOUS CONDITIONS. STAY TUNED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 10 PM CST THIS EVENING FOR WIZ056-
062-063-067>069.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
WIZ064>066-070>072.
LM...NONE.
&&
$$
CORRECTED TO ADD CONFIDENCE DESCRIPTOR TO TIME PERIODS.
SHORT/LONG TERM...09/REM
AVIATION/MARINE...07/DDV
