Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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079
FXUS63 KMKX 081547 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
947 AM CST MON FEB 8 2016

.UPDATE...

STUBBORN SNOW SHOWERS OVER THE EASTERN FORECAST AREA ARE FINALLY
SHOWING A BIT OF SOUTHWARD MOVEMENT AT THIS TIME. LOCALIZED AREAS
HAVE PICKED UP A QUICK 1 TO 3 INCHES THIS MORNING. AFTER THE
CURRENT SHOWERS MOVE ON OR DISSIPATE...MORE SNOW SHOWERS UPSTREAM
WILL MOVE IN FOR THE AFTERNOON AS A SURFACE FRONT/TROUGH DROPS
THROUGH SOUTHERN WISCONSIN. MODEL QPF IS NOT SHOWING MUCH THIS
AFTERNOON...BUT GIVEN THE SLOW MOVING AND LOCALLY MODERATE TO
HEAVY NATURE OF THE SNOW...WOULD NOT BE SURPRISED BY ANOTHER INCH
OR TWO IN SOME SPOTS. BEST CHANCE FOR ADDITIONAL ACCUMULATING
SNOW WILL BE IN THE EASTERN HALF OF THE FORECAST AREA THIS
AFTERNOON INTO EVENING.

TEMPS WILL RISE A COUPLE/FEW DEGREES THIS MORNING INTO THE
AFTERNOON...BUT WILL NOT BE MUCH MILDER THAN CURRENT READINGS.

&&

.AVIATION/18Z TAFS/...

STUBBORN SNOW SHOWERS OVER THE EASTERN FORECAST AREA ARE FINALLY
SHOWING A BIT OF SOUTHWARD MOVEMENT AT THIS TIME. AFTER THE
CURRENT SHOWERS MOVE ON OR DISSIPATE...MORE SNOW SHOWERS UPSTREAM
WILL MOVE IN FOR THE AFTERNOON. WOULD NOT BE SURPRISED BY ANOTHER
INCH OR TWO IN SOME SPOTS. BEST CHANCE FOR ADDITIONAL ACCUMULATING
SNOW WILL BE IN THE EASTERN HALF OF THE FORECAST AREA THIS
AFTERNOON INTO EVENING. SNOW WILL BE DRIER TOWARD THE WEST AND
WETTER IN THE EAST WITH THE MILDER TEMPS. LIGHT SNOW IS EXPECTED
TO PERSIST THROUGH TONIGHT AND MUCH OF TUESDAY...ESPECIALLY IN THE
EAST.

CIGS WILL MAINLY BE MVFR THROUGH TUESDAY...THOUGH SOME VFR HOLES
ARE POSSIBLE. IFR CIGS NOT OUT OF THE QUESTION EITHER...ESPECIALLY
WITHIN MODERATE SNOW SHOWERS. VSBYS WILL BOUNCE AROUND AS
SNOW SHOWERS COME AND GO.

&&

.PREV DISCUSSION... /ISSUED 315 AM CST MON FEB 8 2016/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

THE FIRST OF TWO STRONG COLD FRONTS WILL BE EXITING EASTERN
WISCONSIN RIGHT AROUND SUNRISE...THE SECOND SWEEPS THROUGH LATE
THIS AFTERNOON. THIS WILL MARK THE START OF A RATHER COLD WEEK
AHEAD. THE SCENARIO IS UNCHANGED. A VERY LARGE CLOSED UPPER LOW
WILL CONTINUE TO DROP SOUTH INTO THE GREAT LAKES TODAY. A LONG
DURATION CYCLONIC FLOW PATTERN WILL PERSIST OVER THE REGION INTO
TUESDAY NIGHT. THE OVERALL FORCING REMAINS WEAK.

BUT...THE KEY HERE IS THE MOISTURE DEPTH WHICH IS RATHER
IMPRESSIVE...EXCEEDING 12KFT THROUGH TONIGHT. THE COLD AIR FLOWING
IN WILL STEEPEN THE LOW LEVEL LAPSE RATES WITH THE DENDRITE ZONE
GROWING TO ABOUT 8KFT TONIGHT. NUMEROUS VORTICITY MAX/S WILL BE
ROTATING THROUGH THE UPPER PATTERN AS WELL.

ALL THIS JUST MEANS PERIODS OF SNOW SHOWERS...BUT AMOUNTS WILL BE
QUITE LIGHT. DESPITE ALL THE HIGH POPS IN THE FORECAST...WE/RE
ONLY LOOKING AT 1 TO 1.5 INCHES OF SNOW THROUGH TONIGHT...AND THAT
MAY BE ON THE HIGH SIDE.

TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.

MODELS REMAIN IN PRETTY GOOD AGREEMENT WITH FEATURES DURING THIS
PERIOD. THEY CONTINUE TO TAKE THE 500 MB LOW FURTHER TO THE EAST
SOUTHEAST OF THE AREA TUESDAY INTO TUESDAY NIGHT. ONE FINAL
SHORTWAVE TROUGH WITHIN THE CYCLONIC FLOW SHOULD PASS SOUTHEAST
THROUGH EASTERN PORTIONS OF THE AREA AROUND 06Z WEDNESDAY. OTHER
VORTICITY MAXIMA SHOULD PASS THROUGH PERIODICALLY TUESDAY INTO
TUESDAY EVENING.

AREA FORECAST SOUNDINGS FROM NAM/GFS SHOW SATURATION IN THE LOW
TO MID LEVELS TUESDAY...WITH A DEEP DENDRITE SNOW CRYSTAL GROWTH
ZONE. THE AIR COLUMN THEN DRIES OUT TUESDAY NIGHT FROM WEST TO
EAST...AS COLDER AND DRIER AIR MOVES IN.

THUS...WILL CONTINUE HIGH POPS FOR SNOW SHOWERS IN THE EAST
TUESDAY MORNING...LOWER IN THE WEST. TRENDED THESE DOWNWARD
TUESDAY AFTERNOON AND NIGHT FROM WEST TO EAST. THERE IS SOME
CONCERN THAT THE POPS TUESDAY WILL NEED TO BE RAISED IN THE
WEST...AS THAT AREA LOOKS SIMILAR TO THE EAST WITH MOISTURE
PROFILES AND UPWARD VERTICAL MOTION IN THE DENDRITE ZONE. LIGHT
SNOW ACCUMULATIONS UNDER AN INCH ARE FORECAST AT THIS TIME.

NORTHWEST WINDS WILL REMAIN BRISK TUESDAY INTO WEDNESDAY ACROSS
THE AREA...HELPING REINFORCE THE COLD AIRMASS OVER THE REGION.
HIGH PRESSURE MOVING INTO THE REGION FROM THE NORTHWEST WEDNESDAY
NIGHT WILL HELP WEAKEN THE WINDS AND BRING SOME CLEARING SKIES.

TEMPERATURES WELL BELOW SEASONAL NORMALS ARE EXPECTED TUESDAY
INTO WEDNESDAY NIGHT. WIND CHILLS SHOULD DROP INTO THE 10 BELOW TO
19 BELOW ZERO RANGE LATE TUESDAY NIGHT INTO EARLY WEDNESDAY
MORNING...AND 10 BELOW TO 15 BELOW ZERO BY LATER WEDNESDAY NIGHT.
NOT EXPECTING ADVISORY LEVEL WIND CHILLS AT THIS TIME FOR TUESDAY
NIGHT INTO WEDNESDAY MORNING.

THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS MEDIUM.

THE ECMWF AND GFS ARE SHOWING GENERALLY SIMILAR TRENDS FOR THIS
PERIOD. THEY KEEP THE REGION IN NORTHWEST FLOW AT 500 MB FOR MOST
OF THIS PERIOD. THIS SHOULD HELP STEER ANOTHER ANOTHER CANADIAN
HIGH PRESSURE SYSTEM SOUTHEASTWARD INTO THE REGION SATURDAY. THERE
APPEARS TO BE ANOTHER SHOT OF COLD AIR ADVECTION AHEAD OF THE HIGH
ON FRIDAY. THUS...THE COLD TEMPERATURES SHOULD PERSIST RIGHT INTO
THE WEEKEND...WITH COLD WIND CHILLS AT TIMES.

THERE IS SOME DISAGREEMENT WITH QPF PLACEMENT FOR THURSDAY NIGHT
INTO FRIDAY ACROSS THE REGION. THE ECMWF BRINGS A WIDE SWATH OF
LIGHT QPF ACROSS THE REGION THURSDAY NIGHT INTO FRIDAY
MORNING...WITH THE GFS DRY. THE MAIN 500 MB VORTICITY MAXIMUM
PASSES WELL TO THE SOUTHWEST OF THE AREA...WHERE THE BEST LOW
LEVEL FRONTOGENESIS MAY ALSO BE. SO...KEPT THE FORECAST DRY DURING
THIS TIME. DID BRING SOME CLOUDS SOUTHEASTWARD THROUGH THE AREA
DURING THIS TIME FOR NOW.

MORE DIFFERENCES SHOW UP SUNDAY. THE GFS CRANKS UP WARM AIR
ADVECTION ACROSS THE AREA...WITH THE HIGH REMAINING OVER THE AREA
IN THE ECMWF. KEPT CONSENSUS POPS GOING FOR SUNDAY...WITH CHANGES
PROBABLY OCCURRING AS WE GET CLOSER TO THIS PERIOD.

AVIATION/12Z TAFS/...

MVFR CIGS ARE EXPECTED THROUGH THE TAF PERIOD. WE COULD HAVE A
FEW PERIODS WHERE CIGS/VSBYS DROP BRIEFLY TO IFR LEVELS IN ANY
DECENT SNOW SHOWERS. CONVERSELY...CIGS MAY LIFT TO VFR FOR A TIME
AS WELL. THE OVERALL PATTERN WILL FEATURE A COLD CYCLONIC FLOW
OVER THE REGION THROUGH THE TAF PERIOD...WITH SNOW SHOWERS ON AND
OFF RIGHT THROUGH TUESDAY. DESPITE THE HIGH PROBABILITY OF LIGHT
SNOW...SNOW ACCUMULATIONS WILL BE LIGHT WITH 1 TO 2 INCHES
POSSIBLE OVER THE 36 HOURS OR MORE.

MARINE...

BRISK NORTHWEST WINDS IN THE WAKE OF A DEPARTING LOW PRESSURE
SYSTEM WILL RESULT IN SMALL CRAFT ADVISORY CONDITIONS FROM THIS
EVENING THROUGH EARLY WEDNESDAY EVENING.

&&

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

     SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT CST
     WEDNESDAY NIGHT FOR LMZ643.

&&

$$

UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
TUESDAY THROUGH SUNDAY...WOOD



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