Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 121600 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1000 AM CST FRI DEC 12 2014

.UPDATE...

SOME MODELS ARE SUGGESTING CLEARING SKIES IN THE EAST TODAY...WITH
CLOUDS THEN FILLING BACK IN THIS EVENING. NOT SEEING SIGNS OF THIS
YET THOUGH...AND CLOUD COVER IS PRETTY EXTENSIVE...SO WILL KEEP
CLOUDY SKIES IN THE FORECAST FOR ALL OF THE FORECAST AREA. GIVEN
THE CURRENT TEMPERATURES AND EXPECTED CLOUDS THE REMAINDER OF THE
DAY...FORECAST AFTERNOON HIGHS IN THE LOW TO MID 30S STILL SEEM
REASONABLE.

&&

.AVIATION/18Z TAFS/...

SOME MODELS ARE SUGGESTING CLEARING SKIES IN THE EAST TODAY...WITH
CLOUDS THEN FILLING BACK IN THIS EVENING. NOT SEEING SIGNS OF THIS
YET THOUGH...AND CLOUD COVER IS PRETTY EXTENSIVE...SO WILL KEEP
CLOUDY SKIES IN THE FORECAST THROUGH THE DAY SATURDAY. CIGS WILL
GENERALLY STAY BELOW 1 KFT...WITH SOME IMPROVEMENT TO LOWER MVFR
POSSIBLE AT TIMES...MAINLY THIS AFTERNOON AND AGAIN SATURDAY
AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 350 AM CST FRI DEC 12 2014/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

THE HUMBLING EXPERIENCE OF FORECASTING STRATUS CONTINUES...WITH
LOW CLOUDS RAPIDLY PUSHING BACK EAST OVERNIGHT AND NOW COVERING
ALL OF THE CWA. ALSO GETTING REPORTS OF PATCHY ICE FORMING ON
UNTREATED ROADS AND SIDEWALKS...STEPS ETC. FROM FREEZING FOG. THIS
WILL BE MOST PROBLEMATIC AT LOCATIONS WHERE FOG IS THICK ENOUGH TO
REDUCE VISIBILITIES TO 2 MILES OR LESS.

AGAIN THE GUIDANCE IS AT ODDS OVER TRENDS TODAY WITH MAV GUIDANCE
NOT CATCHING CURRENT CLOUD COVER AT ALL AND KEEPING SKIES
SCATTERED TO CLEAR OVER MOST OF SRN WI INTO SATURDAY
MORNING...WHILE NAM AGAIN IS THE MOST PESSIMISTIC...THOUGH THE 00Z
MET MOS AT MKE HELD OFF ON THE RETURN OF THE STRATUS UNTIL 15Z.

925 MB-850 MB WARM AIR ADVECTION RAISES TEMPS AT THOSE LEVELS 2C
TO 3C BETWEEN 12Z AND 00Z SAT...WHICH WILL ONLY HELP TO STRENGTHEN
INVERSION. WHILE THIS WARMING DOES NOT BREAK THROUGH THE
INVERSION...SOME SURFACE THERMAL AND MOISTURE ADVECTION SPREADS
WEST TO EAST THIS AFTERNOON AND TONIGHT AS SURFACE HIGH CONTINUES
TO SAG SOUTH. EXPECT HIGHS TO REACH THE MID 30S.

TEMPS FALL OFF AFTER SUNSET...WITH OVERNIGHT LOWS AROUND 06Z THEN
STEADY OR SLOWLY RISE THROUGH 12Z SATURDAY. FOG WILL DEVELOP AGAIN
TONIGHT..BUT WILL LEAVE AS PATCHY AS CURRENT TEMP/DEW POINT
SPREADS LOOK TO PREVENT MOST VISIBILITIES FROM FALLING BELOW 2
MILES.

SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT...FORECAST CONFIDENCE
IS MEDIUM.

SOUTHWEST LOW LEVEL FLOW LINGERS ACROSS THE AREA DURING THIS
PERIOD...AS SHOWN ON AREA FORECAST SOUNDINGS FROM NAM/GFS. 500 MB
RIDGE AXIS SHIFTS EAST ACROSS THE REGION DURING THIS TIME. THE
AIR BELOW THE TEMPERATURE INVERSION REMAINS SATURATED FOR MOST OF
THIS PERIOD...WITH THE INVERSION GRADUALLY RISING SATURDAY NIGHT
INTO SUNDAY NIGHT.

GIVEN THE CONTINUED MOISTURE ADVECTION INTO THE AREA SATURDAY
NIGHT INTO SUNDAY NIGHT...COULD SEE LIGHT RAIN OCCUR AT TIMES.
BEST SHOT WOULD BE SUNDAY NIGHT...WITH APPROACH OF LOW PRESSURE
AND 500 MB SHORTWAVE TROUGH FROM THE SOUTHWEST.

ALSO KEPT PATCHY/AREAS OF FOG DURING THIS PERIOD...AS WINDS DO
LIGHTEN UP AT TIMES. TEMPERATURES WILL REMAIN MILD DURING THIS
PERIOD...WITH SOUTH WINDS ACROSS THE AREA. KEPT LOWER TO MID 40S
SATURDAY...WITH MID TO UPPER 40S SUNDAY.

LONG TERM...MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE IS
MEDIUM.

GFS/ECMWF AREA SHOWING DECENT AGREEMENT WITH LOW PRESSURE MOVING
THROUGH THE REGION MONDAY INTO TUESDAY. THE LOW SHIFTS NORTHEAST
ACROSS WISCONSIN LATER MONDAY INTO MONDAY NIGHT...BEFORE MOVING
NORTHEAST OF THE REGION TUESDAY. 500 MB SHORTWAVE TROUGH SLIDES
NORTHEAST THROUGH THE AREA ON MONDAY NIGHT...WITH ANOTHER MORE
SHEARED ONE ON TUESDAY. BOTH MODELS ARE PRODUCING A DECENT AMOUNT
OF QPF...MAINLY RAIN MONDAY INTO MONDAY EVENING...BEFORE MIXING
WITH AND CHANGING TO LIGHT SNOW BY TUESDAY MORNING.

SO...KEPT THE HIGHER END POPS GOING FOR MONDAY INTO MONDAY
NIGHT...WITH LOWER POPS ON TUESDAY. COLDER AIR MOVES INTO THE
REGION MONDAY NIGHT...SO KEPT TRANSITION FROM RAIN TO SNOW GOING.
MAY SEE LIGHT SLEET OCCUR MONDAY NIGHT. WEDNESDAY AND THURSDAY
APPEAR MAINLY DRY AT THIS TIME...WITH THE NEXT SYSTEM REMAINING
WELL SOUTH OF THE AREA. GFS MORE AGGRESSIVE WITH QPF ON
THURSDAY...WITH THE ECMWF WELL SOUTHWEST. KEPT THE DRY FORECAST
GOING FOR NOW.

AVIATION/12Z TAFS/...

IFR CIGS WILL COVER THE FORECAST AREA THIS MORNING...WITH THE
EXPECTATION THAT THEY WILL LIFT TO MVFR LEVELS LATE THIS MORNING
OR EARLY IN THE AFTERNOON AS INVERSION HEIGHT RISES. AGAIN THE
FORECAST SOUNDINGS...EXCEPT FOR THE GFS...ARE INDICATING ENOUGH
DEPTH TO THE CLOUD LAYER TO PREVENT MIXING OUT LIKE YESTERDAY.

WILL KEEP PESSIMISTIC CLOUD FORECAST GOING GIVEN HIGH
PROBABILITIES IN ALL MODELS OF BKN-OVC SKIES THROUGH THE PERIOD.
IFR VSBYS...MAINLY IN WESTERN AREAS...ARE EXPECTED TO RISE TO MVFR
BY MID MORNING WITH VFR VSBYS EVERYWHERE BY THIS AFTERNOON. FOG
RETURNS TONIGHT...BUT EXPECT MAINLY 3-5 MILES AT TAF SITES.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
SATURDAY THROUGH THURSDAY...WOOD


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