National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KGRB 030907
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
307 AM CST TUE MAR 3 2015

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 306 AM CST TUE MAR 3 2015

PRIMARY ISSUES TODAY ARE SNOW AMOUNTS AND TRENDS AND THEN COLDER
WEATHER LATER TONIGHT INTO WEDNESDAY.

A 850 MB SHORT WAVE TROUGH SLIDES OVER THE AREA THIS MORNING AND
EARLY AFTERNOON. THE PRIMARY DYNAMICS OF WAA...FORCING FROM THE
UPPER JET AND THE BETTER SNOW GROWTH REGION ARE DISPLACED ACROSS
THE REGION.

FIRST BAND OF SNOW LIFTING NORTHWARD RUNNING INTO THE DRY AIR
MASS AND A PORTION OF THE MOISTURE USED FOR SATURATION. DID
PRODUCE A MINOR ACCUM DURING PASSAGE. AT 09Z...RADARS TO THE
SOUTH SHOWING A BREAK IN THE PCPN OVER SOUTHERN PORTIONS OF
MINNESOTA AND WISCONSIN AS WELL AS NORTHERN PORTIONS OF ILLINOIS
AND IOWA. BUT RETURNS ARE INCREASING OVER SOUTHERN IOWA AND
CENTRAL ILLINOIS NEAR THE 850 WARM FRONT AND BAROCLINIC ZONE. THIS
AREA OF PCPN OVER ILLINOIS IS ALSO LOOKING RATHER CONVECTIVE WITH
A MIX OF SLEET...FREEZING RAIN AND SNOW BEING REPORTED AT DVN.
THIS CONVECTIVE REGION OF PCPN WAS GRADUALLY LIFTING
NORTHEASTWARD TOWARD SOUTHERN WISCONSIN EARLY THIS MORNING AND AT
PRESENT RATE WILL BE BRUSHING PARTS OF EAST CENTRAL WISCONSIN AT
DAYBREAK. THIS 850 FRONTAL BOUNDARY IS FORECAST TO MOVE INTO
SOUTHERN WISCONSIN THIS MORNING TO INCREASE SNOW COVERAGE ACROSS
THE AREA...AND CONTINUE EARLY AFTERNOON OVER EASTERN WISCONSIN
UNTIL THE SHORT WAVE TROUGH AXIS PASSAGE...SO IF THIS INITIAL BAND
HOLDS TOGETHER...WILL AFFECT MAINLY EAST CENTRAL WISCONSIN.

MEANWHILE THE BETTER FORCING OF THE LFQ OF THE UPPER JET LIFTS
INTO NORTHERN WISCONSIN THIS MORNING BEFORE DIMINISHING THIS
AFTERNOON. COLDER AIR ACROSS THE NORTH ALSO PROVIDES A LARGER SNOW
GROWTH REGION COMPARED TO PARTS OF CENTRAL AND EAST CENTRAL
WISCONSIN. DUE TO THE VARIOUS DYNAMICS IN PLAY...SNOW AMOUNTS WILL
LIKELY VARY WITH THE 2 TO 4 INCH RANGE.

THE PCPN WITH THIS SYSTEM DEPARTS THIS AFTERNOON AS THE SHORT
WAVE TROUGH SHIFTS EASTWARD...ITS POSSIBLE THE GOING ADVISORY
COULD BE DROPPED A BIT EARLIER THAN 6 PM.

WILL BUMP UP TEMPS A TAD TODAY OVER EAST CENTRAL WISCONSIN DUE TO
MORNING TEMPERATURES ARE RUNNING ABOVE GUID LEVELS. COLDER AIR ON
ITS WAY TONIGHT WILL PUSH WIND CHILLS READINGS DOWN NEAR ADVISORY
CRITERIA FOR A FEW HOURS BETWEEN 6 AM AND 9 AM. DUE TO ONGOING
HEADLINES...LATER SHIFTS TODAY CAN REEVALUATE FOR A HEADLINE WHILE
SNOW IS WINDING DOWN THIS AFTERNOON.

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 306 AM CST TUE MAR 3 2015

POSITIVE-TILTED LONGWAVE TROF ACROSS THE CNTRL CONUS AT THE ONSET...
WL MOVE INTO THE ERN CONUS BY THU. A NW FLOW IS EXPECTED TO REMAIN
OVER THE GREAT LAKES INTO THE FIRST PART OF NEXT WEEK...PRIMARILY
DUE TO UPR RIDGING OVER THE WRN CONUS. THE MEAN FLOW IS EXPECTED TO
BE SPLIT WITH THE MORE ACTIVE SRN BRANCH TAKING MOST OF THE SYSTEMS
TO OUR SOUTH. WEAKER NRN BRANCH MAY BRING A WEAK SYSTEM INTO WI THIS
WEEKEND...BUT PCPN AMOUNTS OVERALL TO BE BELOW NORMAL. TEMPS ARE
FCST TO RUN BELOW NORMAL THRU THU NGT WITH SOME MODERATION EXPECTED
BY THE WEEKEND AND BEYOND.

ARCTIC AIR MASS TO RESIDE OVER THE GREAT LAKES WED NGT WITH 8H TEMPS
TO BE IN THE -20 TO -25C RANGE. EXACTLY HOW COLD WE CAN GET WL
ULTIMATELY BE DETERMINED BY THE CLOUDS AS THE LONGWAVE TROF TO PUSH
INTO THE WRN GREAT LAKES WL BE COUNTERED BY AN AREA OF HI PRES
MOVING INTO THE MIDWEST. SINCE THE VAST MAJORITY OF THE MOISTURE TO
HAVE BEEN SHUNTED EAST BY THE DEPARTED WINTER STORM...HARD TO SEE
MUCH IN THE WAY OF CLOUDS (OTHER THAN LAKE EFFECT CLOUDS FROM
SUPERIOR OVER N-CNTRL WI). THEREFORE...ANTICIPATE A VERY COLD NGT
WITH SUB-ZERO MIN TEMPS AND ENUF WIND SUCH THAT WIND CHILL HEADLINES
MAY BECOME NECESSARY.

THE LONGWAVE TROF SHIFTS EAST ON THU...ALLOWING FOR THE SFC HI
(CENTERED OVER THE MID-MS VALLEY) TO BE THE MAIN WEATHER FEATURE FOR
WI. NW WINDS ARE EXPECTED TO GRADUALLY BACK TO THE SW DURING THE DAY
ADN EVEN WITH PLENTY OF SUNSHINE...THU WL BE A COLD DAY WITH TEMPS A
GOOD 20 TO 25 DEGS BELOW NORMAL. THIS WOULD PLACE READINGS ONLY IN
THE UPR SINGLE DIGITS TO MID TEENS.

AS THE SFC HI MOVES UP THE OHIO RIVER VALLEY MON NGT...THE
PREVAILING SW WINDS ARE EXPECTED TO BRING A SURGE OF WAA INTO WI.
8H TEMPS WL RISE INTO THE -6 TO -12C RANGE BY DAYBREAK AND WITH THE
MODELS INDICATING SOME INCREASE IN MOISTURE (CLOUDS)...TEMPS COULD
EASILY REACH MINS IN THE EVENING AND SLOWLY RISE THEREAFTER. THESE
CLOUDS ARE LIKELY TO STICK AROUND THE AREA THRU FRI...ESPECIALLY AS
A WEAK CDFNT APPROACHES LATE IN THE DAY. ANY LIFT/FORCING APPEARS
TOO WEAK TO ALLOW PCPN TO DEVELOP...THUS HAVE MAINTAINED A DRY FCST.
THE WAA PATTERN TO CONT INTO FRI AS 8H TEMPS CLIMB INTO THE -1 TO
-6C RANGE. THIS SHOULD ALLOW MAX TEMPS TO REACH THE LWR 30S OVER
MUCH OF NE WI.

AS THE CDFNT SLIDES ACROSS WI FRI NGT...THERE MIGHT BE ENUF LIFT
PROVIDED TO ALLOW FOR AT LEAST A SMALL CHC OF LIGHT SNOW TO PUSH
INTO NE WI. MOISTURE AVAILABILITY LOOKS RATHER MEAGER...THUS IF
ANY SNOW DOES FALL...ACCUMULATIONS WOULD BE NEGLIGIBLE. SAT SHOULD
BE A QUIET DAY AS ANOTHER AREA OF HI PRES BUILDS ACROSS THE
MIDWEST. DESPITE THE PASSAGE OF THE CDFNT...MAX TEMPS ON SAT
SHOULD BE CLOSE TO FRI`S READINGS MAINLY DUE TO THE MILDER START
TO THE DAY.

MAIN FOCUS FOR THE LATTER PART OF THE WEEKEND WL BE THE MOVEMENT
OF A MODEST CLIPPER SYSTEM DIVING SE TOWARD THE GREAT LAKES. THE
GEM IS BY FAR THE MOST AGGRESSIVE WITH A STRONGER SFC LOW TRACKING
FARTHER SOUTH THAN OTHER MODELS AND IT ALSO HAS A STRONGER
SHORTWAVE TROF IN THE MID-LEVELS. MEANWHILE...THE GFS IS A BIT
WEAKER WITH BOTH THE SFC LOW AND THE SHORTWAVE TROF. DEPENDING ON
THE FINAL TRACK THE SFC LOW TAKES...THERE COULD BE SOME SNOW
SOMEWHERE OVER THE WRN GREAT LAKES ON SUNDAY...BUT WL KEEP POPS
LOW FOR NOW. EVEN WITH CLOUDS AND PCPN IN THE VICINITY...MAX TEMPS
SUNDAY COULD ACTUALLY EDGE ABOVE NORMAL WITH MOST OF NE WI IN THE
MID TO UPR 30S.

WEAK RDG OF HI PRES QUICKLY MOVES ACROSS WI SUNDAY NGT AND THEN
MORE TIMING QUESTIONS ARISE WITH THE NEXT CLIPPER ON MON. TOO FAR
OUT YET TO MAKE A DETERMINATION...THUS HAVE FOLLOWED THE CONSENSUS
SOLUTION WHICH KEEPS THE VAST MAJORITY OF THE FCST AREA DRY...WITH
THE EXCEPTION OF VILAS CNTY TO A PREVAILING NW FLOW ALOFT. MAX
TEMPS BY MON TO RANGE FROM THE UPR 20S N-CNTRL WI...TO THE MID 30S
OVER THE WARMER LOCATIONS OF CNTRL WI (WAUTOMA TO SHAWANO).
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 854 PM CST MON MAR 2 2015

NOT MUCH CHG TO OVERALL FCST THINKING FM PREV TAF PKG. MAIN CHGS
WL BE TO ADJUST TIMING OF THE SNOW TO REFLECT THE LATEST TRENDS IN
THE OBS. THE MOST SIG SNOW WL PROBABLY MV THROUGH DURING THE
MID-LATE MORNING...WITH SNOW TAPERING OFF IN THE AFTN. CAN/T
TOTALLY RULE OUT PCPN CHGG TO FZDZ AS INTENSITY WANES IN THE
AFTN...BUT AT THIS POINT THE PROBABLILITY OF THAT OCCURRING DOES
NOT SEEM GREAT ENOUGH TO WARRANT CARRYING FZDZ IN THE TAFS.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ005-
010>012-018-019-030-035>037-045-048>050.

WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ013-
020>022-031-038>040-073-074.
&&

$$

SHORT TERM.....TDH
LONG TERM......KALLAS
AVIATION.......SKOWRONSKI