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000
FXUS63 KGRB 111022
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
522 AM CDT SAT MAY 11 2013

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 336 AM CDT SAT MAY 11 2013

A STRONG COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING
ACCOMPANIED BY SCATTERED SHOWERS. ADDITIONAL SHOWERS ARE POSSIBLE THIS
AFTERNOON AS A COLD UPPER TROUGH APPROACHES AND DESTABILIZES THE
ATMOSPHERE. THE BEST CHANCE OF SHOWERS THIS AFTERNOON WILL BE IN
NORTHCENTRAL WISCONSIN. SOME SLEET OR SMALL HAIL IS POSSIBLE AS
TEMPERATURES ALOFT ARE QUITE COLD.

RAIN OR SNOW SHOWERS ARE POSSIBLE IN FAR NORTHCENTRAL WISCONSIN
THIS EVENING. WITH 850MB TEMPERATURES JUST ABOUT COLD ENOUGH FOR
LAKE EFFECT PRECIPITATION IT IS NOT OUT OF THE QUESTION FOR A
DUSTING OF WET SNOW ON THE GRASS BUT IT SHOULD NOT BE A BIG DEAL.
THERE IS SOME POTENTIAL FOR FREEZING TEMPERATURES OVER CENTRAL AND
NORTHCENTRAL WISCONSIN LATE TONIGHT AS SKIES CLEAR BUT THINK THAT
A STEADY BREEZE AND DRY AIR WILL INHIBIT FROST FORMATION. WILL
MENTION POSSIBILITY OF A FEW HOURS OF FREEZING TEMPERATURES
TONIGHT BUT HOLD OFF ON ANY HEADLINES RIGHT NOW.

MOTHERS DAY SHOULD BE A BIT BLUSTERY AND COOL FOR MOST OUTDOOR
ACTIVITIES BUT IT SHOULD AT LEAST BE DRY.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 336 AM CDT SAT MAY 11 2013

WHILE LONG-TERM MDLS CONT TO SHOW THE MEAN FLOW DEAMPLIFYING EARLY
NEXT WEEK...THE RESULTANT NEAR ZONAL FLOW WL LEAD TO TIMING ISSUES
AS A COUPLE OF SYSTEMS RACE ACROSS THE CONUS. TRYING TO DECIDE
WHICH PERIODS TO FOCUS PCPN CHCS WL BE THE MAIN FCST OBSTACLE FOR
NEXT WEEK. AFTER A COOL WEEKEND...THE NEAR ZONAL FLOW WOULD BRING
AT OR ABOVE NORMAL TEMPS TO NE WI.

SFC RDG AXIS TO RESIDE OVER ERN WI BY 12Z MON WHICH PROMISES
MAINLY CLEAR SKIES AND LIGHT WINDS. THIS SETS UP WELL FOR
FAVORABLE RADIATIONAL COOLING AND WITH THE AIR MASS STILL QUITE
COLD FOR MAY`S STANDARDS...TEMPS SHOULD NOT HAVE AN PROBLEM
REACHING THE MID 20S FAR NORTH TO THE LWR-MID 30S NEAR LAKE MI.
EXPECT PLENTY OF FROST TO DEVELOP SUNDAY NIGHT WITH SUB-FREEZING
TEMPS OVER MOST OF NE WI. AFTER COLLABORATING WITH OFFICES WHERE
THE GROWING SEASON HAS STARTED...HAVE DECIDED TO ISSUE A FREEZE
WATCH FOR CENTRAL AND MOST OF E-CENTRAL WI FROM 06Z TO 12Z MON.

THE SFC RDG SLIDES TO OUR EAST ON MON AND ALLOWS FOR A RETURN FLOW
TO DEVELOP ACROSS WI WITH THE MDLS CONTINUING TO SHOW AN IMPRESSIVE
SURGE OF WAA SPREADING OVER THE STATE. THE BEST ISEN LIFT APPEARS
TO BE TO OUR WEST WHERE THE TIGHT BAROCLINIC ZONE TO RESIDE AND
THERE ARE QUESTIONS AS TO HOW MUCH MOISTURE WL BE AVAILABLE TO HELP
GENERATE ANY SHOWER ACTIVITY. THE LIFT SHOULD AT LEAST BE
SUFFICIENT TO BRING A GENERAL INCREASE IN CLOUDS TO THE FCST
AREA...BUT ANTICIPATE MEASURABLE PCPN TO REMAIN MAINLY OVER WRN
WI. TEMPS WL BEGIN THEIR UPSWING ON MON AS THE WARMER PACIFIC AIR
REACHES WI AS MAX TEMPS TO RANGE FROM A LAKE-COOLED MID 50S ALONG
THE SHORELINE TO THE LWR 60S OVER PARTS OF CNTRL WI.

MDLS ARE CONSISTENT IN PRODUCING LIGHT SHOWERS OVER NE WI MON NGT
AS AN INCREASE IN ISEN LIFT IS AIDED BY THE NWD MOVEMENT OF A
WRMFNT INTO WI. CHC POPS STILL LOOK GOOD FOR NOW AND KEPT THUNDER
OUT FOR NOW AS INSTABILITY PARAMETERS ARE NOT THAT IMPRESSIVE. MIN
TEMPS TO BE A GOOD 15 TO 20 DEGS MILDER COMPARED TO SUNDAY NGT AS
SW WINDS KICK IN AND 8H TEMPS APPROACH +10C. MAIN QUESTION FOR TUE
CONTS TO BE EXACTLY WHERE THIS WRMFNT WL RESIDE AS ITS LOCATION WL
NOT ONLY IMPACT PCPN CHCS...BUT ALSO TEMPS. THE ECMWF/GEM GENERALLY
HOLD THE FNT OVER SRN WI WHICH WOULD KEEP SPOTTY SHOWERS OVER AT
LEAST NRN WI AND KEEP TEMPS IN CHECK. THIS HAS BEEN A CONSISTENT
SIGNAL BY THESE MDLS...THUS FAVOR KEEPING A SMALL POP OVER NRN WI
AND HOLDING BACK ON THE REALLY WARM AIR TO OUR SW. EVEN SO...LOOK
FOR MAX TEMPS TO RANGE FROM THE 60S LAKESIDE TO THE UPR 70S OVER
CNTRL WI.

PCPN CHCS TO PERSIST OVER THE REGION TUE NGT INTO WED AS THE WRMFNT
TRIES TO LIFT FARTHER NORTH TUE NGT...ONLY TO SEE A CDFNT PUSH INTO
WI ON WED. ECMWF IS SLOWER WITH THE PASSAGE OF THE CDFNT AND APPEARS
TO GIVE A SE CONUS WEAK UPR RDG TOO MUCH CREDIT. CURRENT THINKING IS
TO BRING THE CDFNT THUR NE WI LATE TUE NGT/WED MORNING AND KEEP
MOVING THE CDFNT SEWD AWAY FROM THE REGION WED AFTERNOON. FCST
THEN REMAINS SOMEWHAT MUDDLED THRU THE END OF THE WORK WEEK AS THE
ECMWF STALLS THE CDFNT JUST TO OUR SOUTH...WHILE THE GFS BEGINS TO
AMPLIFY THE MEAN FLOW ONCE AGAIN WITH A WRN CONUS UPR TROF/CNTRL
CONUS UPR RDG AND A WEAK SHORTWAVE TROF ARRIVING AROUND FRI.
CONFIDENCE IS RATHER LOW FOR BOTH NEXT THU AND FRI AND GENERALLY
FOLLOWED A CONSENSUS SOLUTION WHICH KEEPS LOW POPS IN THE FCST FOR
BOTH DAYS.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 521 AM CDT SAT MAY 11 2013

A PERIOD OF MVFR CEILINGS POSSIBLE THIS MORNING ALONG
WITH SCATTERED RAIN SHOWERS AS A COLD FRONT MOVES ACROSS THE AREA.
PARTIAL CLEARING WITH GUSTY NORTHWEST SURFACE WINDS THIS AFTERNOON
WITH SCATTERED SHOWERS AGAIN LATE IN THE AFTERNOON AND EARLY
EVENING ESPECIALLY IN FAR NORTHERN WISCONSIN. SKIES SHOULD CLEAR
ACROSS MOST OF THE AREA TONIGHT WITH A SMALL CHANCE OF FROST IN
CENTRAL WISCONSIN. MOSTLY SUNNY SUNDAY WITH GUSTY NORTHWEST
SURFACE WINDS.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
WIZ020-030-031-035>040-045-048>050-073-074.
&&

$$

SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......RDM