Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 181146
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
646 AM CDT FRI APR 18 2014

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 335 AM CDT FRI APR 18 2014

THE MAIN FCST CONCERNS ARE TEMPERATURES...AND PCPN TRENDS ON SATURDAY.

LOW CLOUDS WERE GRADUALLY CLEARING FROM WEST TOO EAST EARLY THIS
MORNING. PATCHY FOG DEVELOPED OVER NC WI AS THE CLEARING OCCURRED...
DUE TO RAPIDLY FALLING TEMPS OVER THE FRESH AND DEEP SNOW COVER.

PATCHY/AREAS OF FOG SHOULD MIX OUT OVER NC/FAR NE WI EARLY THIS
MORNING...OTHERWISE HIGH PRESSURE WILL BRING PARTLY SUNNY SKIES
TO THE FCST AREA. MIXING THROUGH ABOUT 850 MB SUPPORTS HIGH TEMPS
IN THE UPPER 40S AND LOWER 50S WHERE THERE IS NO SNOW COVER. HAVE
GONE A FEW DEGREES BLO GUIDANCE OVER NC/FAR NE...OVER THE DEEP
SNOW PACK...WHERE READINGS IN THE UPPER 30S AND LOWER 40S ARE
ANTICIPATED.

HIGH PRESSURE WILL SHIFT EAST TONIGHT...ALLOWING RETURN FLOW TO
DEVELOP. DESPITE INCREASING WAA OVER OUR WSTRN COUNTIES...MODELS
SUGGEST THAT ENOUGH DRY AIR WILL REMAIN IN THE LOWER TO MID LEVELS
TO PRECLUDE PCPN DEVELOPMENT. THOUGH MOS GUIDANCE DOESN`T SHOW
THE TREND...TEMPS MAY WARM A BIT OVERNIGHT DUE TO WAA AND INCREASING
CLOUDS.

WAA WILL INCREASE OVER THE FCST AREA ON SATURDAY...ON THE NOSE OF
A 30-50 KT LLJ (STRONGEST OVER THE NW 1/2 OF THE CWA). THE BEST
FORCING AND SATURATION IS EXPECTED OVER N WI...SO PCPN CHANCES WILL
BE FOCUSED THERE...WITH THE HIGHEST POPS (LIKELY) NEAR THE UPPER
MICHIGAN BORDER. A LIGHT MIX OF SNOW/SLEET IS EXPECTED OVER NC WI
EARLY IN THE DAY...WITH RAIN ANTICIPATED FOR THE LATE MORNING AND
AFTERNOON. WILL SEE A LARGE TEMPERATURE GRADIENT OVER THE REGION
ON SATURDAY AFTERNOON...WITH READINGS IN THE 40S OVER THE NORTH
(SNOW PACK AND CLOUDS/PCPN)...BUT RISING INTO THE UPPER 50S TO
MIDDLE 60S OVER PARTS OF C/EC WI.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 335 AM CDT FRI APR 18 2014

THE MEDIUM RANGE MODELS ARE IN VERY GOOD AGREEMENT THROUGH THE
MIDDLE OF NEXT WEEK WITH THE LARGE SCALE FEATURES. THE MAIN FOCUS
IN THIS PERIOD CONTINUES TO REVOLVE AROUND RAIN CHANCES FOR THE
SECOND HALF OF THE WEEKEND INTO EARLY NEXT WEEK. THE GFS IS
SLIGHTLY MORE PROGRESSIVE WITH A WEAK COLD FRONT LATE SUNDAY INTO
MONDAY THAN THE ECMWF. THE APPEAL TO THE GEM INDICATES SUPPORT FOR
THE SLOWER FRONTAL PASSAGE...SO WILL SIDE TOWARDS THE CONSISTENT
SOLUTION OF THE ECMWF.

SATURDAY NIGHT THROUGH SUNDAY NIGHT...A CLOSED SHORTWAVE WILL LIFT
NORTHEAST ACROSS SOUTH-CENTRAL CANADA SATURDAY NIGHT...BUT WILL
STILL HAVE WEAK HEIGHT FALLS TO HELP SAG A COOL FRONT SLOWLY INTO
NORTH-CENTRAL WISCONSIN.  AHEAD OF THE FRONT...MODEST MOISTURE
TRANSPORT WITHIN THE MID-LEVEL THETAE AXIS ALONG WITH UPPER
DIVERGENCE IN THE RIGHT REAR QUAD OF A JET STREAK WILL PROVIDE THE
FOCUS FOR OCCASIONAL LIGHT RAIN.  THE RAIN SHOULD MAINLY BE OVER THE
NORTHWEST HALF OF THE FORECAST AREA DURING THE EVENING BEFORE
SPREADING TO THE REST OF THE FORECAST AREA OVERNIGHT.  NOT LOOKING
AT ALOT OF RAIN DESPITE PWATS OVER AN INCH...BUT PERHAPS A TENTH OR
TWO.  THE CHANCE OF RAIN WILL CONTINUE ON SUNDAY ALONG THE FRONT
OVER CENTRAL AND NORTHEAST WISCONSIN.  ENOUGH DRY AIR MAY BE PRESENT
TO KEEP N-C WISCONSIN PRECIP FREE THOUGH.  THE FRONT MOVES VERY
LITTLE ON SUNDAY NIGHT...AND ADDITIONAL SHORTWAVE FORCING COULD MAKE
THE FRONT MORE ACTIVE.  THEREFORE...THE THREAT OF PRECIP WILL
CONTINUE OVER THE SOUTHEAST HALF OF THE FORECAST AREA SUNDAY NIGHT.

REST OF THE FORECAST...WITH SHORTWAVE ENERGY AND THE RIGHT REAR QUAD
OF A JET STREAK OVERHEAD...PRECIP CHANCES WILL CONTINUE OVER CENTRAL
AND NORTHEAST WISCONSIN ON MONDAY.  FINALLY...THE SUPPORT ALOFT IS
PROGRESSIVE ENOUGH TO PUSH THE FRONT TO THE EAST BY MONDAY NIGHT AND
WILL START THE FIRST DRY PERIOD THEN.  HIGH PRESSURE THEN BUILDS IN
FOR TUESDAY AND TUESDAY NIGHT WHICH WILL CONTINUE THE DRY
CONDITIONS...BUT TEMPS WILL BE SLIGHTLY BELOW NORMAL.  THE NEXT
CHANCE OF RAIN WILL ARRIVE LATE WEDNESDAY INTO THURSDAY WHEN A DEEP
WESTERN NOAM TROUGH MOVES INTO THE PLAINS.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 639 AM CDT FRI APR 18 2014

MVFR CIGS WILL GRADUALLY CLEAR OUT OF NE/EC WI THIS MORNING...AND
SHOULD EXIT THE MTW VCNTY BY AROUND 15Z. PATCHY IFR/LIFR CONDITIONS
IN FOG WILL ALSO END ACROSS NC/FAR NE WI EARLY TODAY. OTHERWISE...
EXPECT SCT-BKN MID-LEVEL CLOUDS TO IMPACT THE REGION THROUGH THE
TAF PERIOD. LIGHT NORTH WINDS WILL BECOME EASTERLY LATER TODAY
INTO TONIGHT.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....KIECKBUSCH
LONG TERM......MPC
AVIATION.......KIECKBUSCH






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