000
FXUS63 KGRB 240350
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1050 PM CDT THU MAY 23 2013

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.UPDATE...
ISSUED AT 857 PM CDT THU MAY 23 2013

NO CHANGE TO THE HEADLINES TONIGHT. WINDS ARE IN THE PROCESS OF
DIMINISHING AS EXPECTED...AND THE 00Z GRB SOUNDING SHOWS A PWAT OF
0.26 INCHES...WHICH IS AN INDICATION OF VERY DRY AIR OVERHEAD.
THINK EAST-CENTRAL AND NORTHEAST WISCONSIN WILL NOT FULLY DECOUPLE
UNTIL LATE TONIGHT...WHICH WILL KEEP THIS AREA RELATIVELY SAFER
FROM FROST THAT FURTHER WEST AND NORTH. BUT OUTLYING AREAS COULD
STILL SEE PATCHY FROST.
&&

.SYNOPSIS...
ISSUED AT 240 PM CDT THU MAY 23 2013

HIGHLY AMPLIFIED PATTERN WAS IN PLACE OVER THE CONUS THIS
AFTERNOON. WEAKENING UPPER LEVEL TROUGH CONTINUED TO PUSH EAST OUT
OF THE GREAT LAKES REGION TODAY...TAKING WITH IT ANY LEFT OVER
RAIN SHOWERS. EXPECT THE TROUGH/RIDGE/TROUGH PATTERN IN THE UPPER
LEVELS TO CONTINUE THROUGH THE WEEKEND...WITH BELOW NORMAL TEMPS
THROUGH THE BEGINNING OF NEXT WEEK BEFORE WARMING UP STARTING
MONDAY. THE NEXT CHC FOR SIG PRECIP PROBABLY WONT ARRIVE UNTIL THE
MIDDLE OR LATE NEXT WEEK.
&&

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 240 PM CDT THU MAY 23 2013

TONIGHT AND FRIDAY
MAIN FORECAST CONCERN FOR THE SHORT TERM WILL BE TEMPERATURES
OVERNIGHT...WHICH COULD SET NEW RECORD LOWS. OTHERWISE...CLEAR
SKIES AND QUIET WEATHER IS EXPECTED THROUGH FRIDAY.

DIDNT NEED TO CHANGE TOO MUCH FROM THE PREVIOUS FORECAST. MODELS
ALL HAVE CLEAR SKIES AND LIGHT WINDS TONIGHT AS HIGH PRESSURE
CONTINUES TO SPREAD INTO WISCONSIN. THIS...COMBINED WITH DRY AIR
BEING FILTERED IN FROM CANADA...WILL ALLOW FOR TEMPERATURES TO
DROP OFF QUICKLY TONIGHT. LINGERING CLOUDS THIS MORNING OVER THE
NORTH AND EAST KEPT TEMPERATURES A FEW DEGREES COOLER THAN
EXPECTED TODAY...SO DECREASED OVERNIGHT LOWS A DEGREE OR TWO.
COULD SEE TEMPERATURES IN THE TYPICAL COLD SPOTS DIP BELOW 20
DEGREES. CURRENT FROST AND FREEZE HEADLINES IN PLACE TO HIGHLIGHT
THE COLDER TEMPERATURES TO THE GROWING COMMUNITY AND SEEM
REASONABLE. DEBATED ADDING MARATHON COUNTY TO THE FREEZE WARNING
AS TEMPERATURES COULD GET BELOW 32 DEGREES IN A FEW
LOCATIONS...HOWEVER IT SHOULD BE JUST A FEW SPOTS FOR AN HOUR OR
SO. WILL ADD LOCALIZED FREEZE WORDING TO THE FROST ADVISORY THAT
IS CURRENT IN EFFECT FOR THIS AREA INSTEAD.

FRIDAY SHOULD BE ANOTHER SUNNY DAY. TEMPERATURES WILL STILL BE
BELOW NORMAL FOR THIS TIME OF THE YEAR WITH CHILLY NORTHWEST FLOW
PERSISTING OVER THE REGION. HOWEVER...WITH LIGHTER WINDS THAN
TODAY
AND WARMING 850MB TEMPERATURES...IT WILL BE WARMER THAN WHAT WE
SAW TODAY. STILL HAD TO DROP A DEGREE OR TWO OFF OF HIGH TEMPS
TOMORROW TO COMPENSATE FOR LOWERING OF OVERNIGHT TEMPERATURES.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 240 PM CDT THU MAY 23 2013

MAIN FORECAST CONCERNS INCLUDE FROST POTENTIAL FRIDAY NIGHT AND
SATURDAY NIGHT...WHETHER OR NOT TO INCLUDE PCPN CHANCES OVER THE
HOLIDAY WEEKEND...THEN A WARMUP AND TSTM POTENTIAL INTO MIDWEEK.

ALTHOUGH A WEAK S/W TROF AND A JET STREAK MAY BRING A SLIGHT
CHANCE OF SHOWERS TO CENTRAL WI LATE FRIDAY NIGHT INTO SATURDAY
MORNING...MOST OF THE REGION WILL STAY PARTLY CLOUDY AND DRY
DUE TO THE PRESENCE OF CANADIAN HIGH PRESSURE. GOOD RADIATIONAL
COOLING WILL LEAD TO SOME FROST POTENTIAL OVER THE NORTHEAST
THIRD OF THE CWA ON FRIDAY NIGHT AND SATURDAY NIGHT...AS MIN
TEMPS DROP INTO THE LOWER TO MIDDLE 30S.

HAVE FOCUSED MORE ON THE ECMWF...WHICH IS REGARDED AS THE BEST
MEDIUM RANGE MODEL AND HAS BEEN THE MOST CONSISTENT OVER THE PAST
FEW DAYS...FOR THE END OF THE HOLIDAY WEEKEND. THE ECMWF KEEPS THE
LARGE CANADIAN SFC HIGH RIDGED OVER THE REGION THROUGH THE
PERIOD...AND SUPPORTS A COMPLETELY DRY FCST. THIS SCENARIO IS
SUPPORTED BY HPC...THE LATEST RUN OF THE UKMET...AND EVEN A FEW OF
THE GFS ENSEMBLE MEMBERS. TO ACCOUNT FOR THE WETTER GFS/GEFS/GEM
MODELS...HAVE KEPT TOKEN SLIGHT CHANCE POPS OVER THE SW PART OF
THE CWA FROM SUNDAY NIGHT INTO MONDAY.

PCPN CHANCES WILL INCREASE AS A WARM FRONT LIFTS INTO THE REGION
DURING THE MIDWEEK PERIOD. THE FRONT WILL BRING ABOVE NORMAL
TEMPS...ALONG WITH INCREASING MOISTURE AND INSTABILITY. IT IS
DIFFICULT TO GAUGE THE SEVERE TSTM THREAT THIS FAR OUT...BUT THE
PRESENCE OF A WARM FRONT...AND THE ECMWF SHOWING CAPE OF 1500-2000
J/KG...MID-LEVEL LAPSE RATES AROUND 7 C/KM...AND DEEP LAYER SHEAR
OF 30-40 KTS INDICATES SOME POTENTIAL.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1050 PM CDT THU MAY 23 2013

GOOD FLYING WEATHER OVER THE NEXT 24 HOURS THANKS TO AN
INCOMING HIGH PRESSURE SYSTEM.  THE COLD AIRMASS WILL PROMOTE FROST
FORMATION ON AIRCRAFT LATE TONIGHT.  INCREASING HIGH CLOUDS FRIDAY
AFTERNOON AND EVENING...BUT VFR CONDITIONS TO PREVAIL.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 7 AM CDT FRIDAY FOR WIZ020-022-030-031-
035>040-045-048>050-073-074.

FREEZE WARNING UNTIL 7 AM CDT FRIDAY FOR WIZ005-010>013-018-019-
021.
&&

$$

UPDATE.........MPC
SYNOPSIS.......WOLF
SHORT TERM.....WOLF
LONG TERM......KIECKBUSCH
AVIATION.......MPC