Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 250237
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
837 PM CST SAT JAN 24 2015

.UPDATE...

00Z NAM CONTINUES THE TREND OF TAKING THE CLIPPER FARTHER SOUTH.
NAM HAS LESS SNOW...SO WILL TRIM FORECAST AMOUNTS EVEN
MORE...ALTHOUGH NOT QUITE AS MUCH AS THE LATEST HRRR WHICH KEEPS
ALMOST ALL SNOW SOUTH OF THE ILLINOIS BORDER. ALSO WITH NORTHEAST
WINDS EXPECT SOME LIGHT LAKE EFFECT SNOW SUNDAY. INVERSION LOWERS
TO 25 HUNDRED FEET SUNDAY AFTERNOON...SO LITTLE IN THE WAY OF
ACCUMULATIONS.

&&

.AVIATION/06Z TAFS/...

EXPECT MVFR CIGS/VSBYS SPREAD SOUTHEAST WITH AN AREA OF LIGHT SNOW
FROM THE UPSTREAM CLIPPER TYPE LOW. THE LOW SHOULD TRACK ACROSS
CENTRAL IOWA TO CENTRAL/SOUTHERN ILLINOIS SUNDAY MORNING. SOME
POCKETS OF IFR CONDITIONS EXPECTED. WEST WINDS WILL GRADUALLY
WEAKEN INTO TONIGHT...THEN BECOME GUSTY OUT OF THE NORTHEAST BY
12Z SUNDAY. THESE WINDS WILL LINGER ON SUNDAY...WITH GUSTS TO 25
KNOTS POSSIBLE. ALSO WITH NORTHEAST WINDS EXPECT SOME LIGHT LAKE
EFFECT SNOW SUNDAY.

&&

.PREV DISCUSSION... /ISSUED 331 PM CST SAT JAN 24 2015/

TONIGHT AND SUNDAY...FORECAST CONFIDENCE IS HIGH.

EXPECT MIDDLE TO HIGH CLOUDS TO FILL BACK IN ACROSS THE FAR WESTERN
COUNTIES THAT HAVE SEEN SOME CLEARING THIS AFTERNOON. LOW CLOUDS
WILL THEN FILL IN THIS AREA LATER TONIGHT INTO SUNDAY. LOW CLOUDS
SHOULD REMAIN ACROSS THE REST OF THE AREA INTO SUNDAY.

MODELS ARE FINALLY IN DECENT AGREEMENT WITH THE TRACK OF THE SURFACE
LOW AND 500 MB SHORTWAVE TROUGH ACROSS THE REGION. THEY BRING IT
SOUTHEASTWARD FROM SOUTHWEST MINNESOTA TO FAR NORTHEAST MISSOURI
TONIGHT...THEN INTO CENTRAL KENTUCKY ON SUNDAY. THE BULK OF THE 500
MB SHORTWAVE TROUGH MISSES THE AREA TO THE SOUTHWEST DURING THIS
TIME.

ENOUGH LOW LEVEL Q VECTOR CONVERGENCE CROSSES THE AREA TO CONTINUE
THE HIGHER END POPS FOR LIGHT SNOW LATER TONIGHT INTO SUNDAY
MORNING. LOWERED SNOWFALL AMOUNTS A BIT ACROSS THE AREA...WITH THE
BEST UPWARD VERTICAL MOTION TO THE SOUTHWEST.

AMOUNTS OF 1/2 INCH TOWARD SHEBOYGAN...TO AROUND 1 INCH IN
MADISON/MILWAUKEE/KENOSHA...TO AROUND 2 INCHES IN DARLINGTON ARE
EXPECTED. NO LAKE ENHANCEMENT IS EXPECTED...AS DELTA T VALUES ARE
NOT FAVORABLE SUNDAY...WITH VERY DRY AIR ABOVE THE INVERSION
DEVELOPING DURING THE AFTERNOON. TEMPERATURES TONIGHT WILL DROP INTO
THE 20S IN MOST OF THE AREA...WITH NEARLY STEADY TEMPERATURES ON
SUNDAY.

SHORT TERM...SUNDAY NIGHT THROUGH TUESDAY.

SUNDAY NIGHT...FORECAST CONFIDENCE HIGH

THE 12Z 12KM NAM HAS DONE AWAY WITH THE LAKE-EFFECT POTENTIAL WITH
ONSHORE 1000-900MB CONVERGENCE DISSIPATING RAPIDLY EARLY SUNDAY
EVENING AS GRADIENT EASES WITH CLIPPER LOW MOVING AWAY TO THE
SOUTHEAST AND WEAK RIDGE OF HIGH PRESSURE BUILDING IN. 925 MB DIP TO
THEIR LOWEST POINT AROUND 06Z...THEN STEADY OUT AND BEGIN TO RISE
TOWARDS MORNING WITH DEVELOPING SW FLOW AHEAD OF NEXT SHORT WAVE.
SHOULD SEE LOWS OF 10 TO 15 AROUND MIDNIGHT...THEN REMAIN STEADY.
LAKESHORE LOCATIONS WILL SEE READINGS HOLD UP HIGHER WITH RELATIVELY
WARMER ONSHORE FLOW.

MONDAY AND MONDAY NIGHT...FORECAST CONFIDENCE MEDIUM

WARM AIR ADVECTION AHEAD OF NEXT SHORT WAVE IN THE NWLY FLOW BRINGS
SLIGHT CHANCES TO NWRN PORTIONS OF CWA MONDAY MORNING...AND
OVERSPREADS ALL OF SRN WI MONDAY AFTERNOON. TRACK OF WAVE AND
SURFACE LOW KEEP BETTER FORCING...DEEP LAYER Q-VECTOR
CONVERGENCE/FRONTOGENETIC RESPONSE...AND DEEP MOISTURE TO THE
NORTHEAST.

INITIAL PCPN SHOULD BE ALL LIGHT SNOW WITH A SATURATED DENDRITE
GROWTH ZONE...TOUGH AMOUNTS WILL BE LIMITED BY DRY AIR BELOW 5K
FT...THEN MID-LEVELS DRY OUT WITH THE LOWER LAYERS SATURATING...BUT
OUT OF THE DENDRITE GROWTH ZONE. EXPECT A TRANSITION TO FREEZING
RAIN WHEN CRYSTALS ARE LOST. NOT MUCH ICE ACCUMULATION WITH PCPN
DIMINISHING AS LOW SHEARS OUT AND IS ABSORBED BY DEEPENING EAST
COAST LOW...AND COLUMN DRIES EARLY MONDAY EVENING.

TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE HIGH.

A DRY PERIOD AS HIGH PRESSURE MOVES ACROSS THE REGION. LITTLE IN THE
WAY OF TEMPERATURE ADVECTION AS 925-850 MB BAROCLINIC ZONES REMAIN
PARALLEL TO THE FLOW. LOOKING FOR HIGHS IN THE MID 30S AND LOWS IN
THE LOW 20S WITH TEENS IN THE FAR NORTH.

LONG TERM...WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM

NEXT SYSTEM TO AFFECT REGION MOVES IN WEDNESDAY NIGHT AND THURSDAY
AS A NORTHERN STREAM SHORT WAVE MERGES WITH A WAVE THAT TRACKS FROM
THE SRN CALIFORNIA COAST TO THE CENTRAL PLAINS. MODELS IN VERY GOOD
AGREEMENT IN TAKING A BROAD LEE TROUGH IN THE PLAINS AND CONSOLIDATE
IT INTO A RAPIDLY DEEPENING SURFACE LOW OVER NRN HALF OF IL BY
THURSDAY MORNING. THERMAL STRUCTURE INDICATES SRN CWA WILL SEE A
RAIN SNOW MIX WITH MAINLY LIGHT SNOW NORTHERN HALF. QPF AMOUNTS ARE
LOW WITH QPF MAX STAYING SOUTH CLOSER TOT HE LOW CENTER.


MODELS DIFFER ON WHETHER OR NOT TO BRING A SHORT WAVE INTO THE
REGION SATURDAY. 12Z ECMWF BRINGS A WAVE IN SATURDAY
AFTERNOON/EVENING FOLLOWED BY SOME OF THE COLDEST AIR OF THE SEASON
WHILE GFS KEEPS THE WAVE OVER SRN CANADA AND DELAYS INTRUSION OF
ARCTIC AIR.

AVIATION/00Z TAFS/...

EXPECT IFR CEILINGS TO SPREAD EAST ACROSS TAF SITES BY EARLY THIS
EVENING. THESE CEILINGS WILL LINGER TONIGHT INTO SUNDAY...BECOMING
MVFR LATER IN THE DAY. WEST WINDS WILL GRADUALLY WEAKEN INTO
TONIGHT...THEN BECOME GUSTY OUT OF THE NORTHEAST BY 12Z SUNDAY.
THESE WINDS WILL LINGER ON SUNDAY...WITH GUSTS TO 25 KNOTS POSSIBLE.

LIGHT SNOW WITH 1 MILE VISIBILITIES WILL SPREAD INTO MADISON BY 09Z
SUNDAY...AND THE EASTERN SITES BY 11Z SUNDAY. THE LIGHT SNOW WILL
LINGER THROUGH MOST OF THE MORNING...ENDING BETWEEN 16Z TO 18Z
SUNDAY. SNOWFALL RATES OF 0.1 TO 0.2 INCHES PER HOUR ARE EXPECTED.
TOTAL AMOUNTS OF AROUND 1 INCH ARE EXPECTED.

MARINE...

SMALL CRAFT ADVISORY CONTINUES LATER TONIGHT INTO SUNDAY EVENING
ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN. A TIGHT PRESSURE
GRADIENT WILL DEVELOP DURING THIS TIME...RESULTING IN GUSTY
NORTHEAST WINDS. GUSTS TO 30 KNOTS ARE POSSIBLE AT TIMES...WITH HIGH
WAVES OF 4 TO 6 FEET. FREEZING SPRAY IS ANTICIPATED WITH THE
EXPECTED WINDS AND WAVES.

GUSTY WINDS...HIGH WAVES AND SOME FREEZING SPRAY ARE POSSIBLE
THURSDAY INTO THURSDAY NIGHT...AS LOW PRESSURE PASSES BY TO THE
SOUTH OF THE AREA.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 AM SUNDAY TO MIDNIGHT CST SUNDAY
     NIGHT FOR LMZ644>646.

     SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM CST SUNDAY
     FOR LMZ643.

&&

$$

UPDATE...HENTZ
TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD
SUNDAY NIGHT THROUGH SATURDAY...REM


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