Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 130843
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
343 AM CDT SAT SEP 13 2014

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 343 AM CDT SAT SEP 13 2014

MAIN FCST CONCERNS THRU TNGT TO BE ON TEMPS AND THE POTENTIAL FOR
PATCHY FROST ONCE AGAIN TNGT. THE MAIN ISSUE FOR SUNDAY TO BE THE
EXTENT OF PCPN CHCS AHEAD OF THE NEXT SYSTEM.

THE 07Z MSAS SFC ANALYSIS SHOWED AN AREA OF LOW PRES OVER THE TN
VALLEY WITH AN INVERTED TROF EXTENDED N-NW INTO THE ERN GREAT
LAKES. FARTHER TO THE WEST...A BROAD AREA OF HI PRES STRETCHED
FROM THE CNTRL PLAINS N-NE INTO THE UPR MS VALLEY. SATL IMAGERY
EARLY THIS MORNING STILL SHOWED PLENTY OF CLOUDS ACROSS NE WI...
BUT THE CLEARING LINE WAS OVER WRN WI. RADAR MOSAIC INDICATED THE
BACK EDGE OF THE STEADY LIGHT RAIN WAS ABOUT TO PULL AWAY FROM THE
LAKESHORE COUNTIES...ALTHO SPOTTY DRIZZLE WAS LEFT BEHIND ACROSS
NRN WI.

THE STRONG SHORTWAVE TROF IN THE MID-LEVELS OF THE ATMOSPHERE
RESPONSIBLE FOR THE LIGHT RAIN OVRNGT QUICKLY GETS SHUNTED E-NE
INTO SE CANADA BY AN UPSTREAM WEAKER SHORTWAVE TROF MOVING INTO
SRN MANITOBA/NRN PLAINS. IN BETWEEN THESE SYSTEMS...THE LARGE AREA
OF HI PRES WL MOVE INTO THE GREAT LAKES/MIDWEST FOR TODAY. SKIES
WL BE MOSTLY SUNNY OVER MOST OF NE WI...ALTHO THERE WL BE AN
INCREASE IN HI CLOUDS LATE THIS AFTERNOON...ESPECIALLY OVER
N-CNTRL WI IN ADVANCE OF THE NEXT SYSTEM. THE RETURN OF SUNSHINE
SHOULD PROVIDE A BOOST IN TEMPS...BUT THE AIR MASS ALOFT IS STILL
QUITE COOL BY SEPTEMBER STANDARDS (8H TEMPS AROUND +1C). EXPECT
MAX TEMPS TO MAINLY END UP IN THE 55-60 DEG RANGE OR 10 TO 15 DEGS
BELOW NORMAL.

AS THE SFC HI SLIDES EWD AND EXTENDS FROM THE MID-MS VALLEY TO THE
ERN GREAT LAKES TNGT...A RETURN FLOW SETS UP OVER WI. THE NEXT
SHORTWAVE TROF IS FCST TO MOVE E-SE AND REACH THE UPR MS VALLEY...
ACCOMPANIED BY A CDFNT CUTTING SE FROM NRN MN TO CNTRL NEBRASKA.
LOOK FOR HI CLOUDS TO THICKEN OVER NE WI THRU THE NGT AND WITH A
SW BOUNDARY LAYER WIND AT 10 TO 20 KTS...TEMPS SHOULD NOT BE AS
COLD AS PREVIOUS NGTS. NEVERTHELESS...MIN TEMPS ARE FCST TO DROP
INTO THE 35-40 DEG RANGE WEST OF A Y50-IMT LINE AND WL INCLUDE
PATCHY FROST IN THE FCST.

THE SHORTWAVE TROF IS PROGGED TO MOVE INTO NRN SECTIONS OF THE
GREAT LAKES ON SUNDAY WITH THE CDFNT TO STRETCH ROUGHLY FROM
S-CNTRL ONTARIO SWWD THRU N-CNTRL WI TO W-CNTRL IA BY 00Z MON.
TYPICALLY...THIS SYNOPTIC SET-UP WOULD PROVIDE FOR A DECENT CHC OF
PCPN. HOWEVER...THE BEST PV ADVECTION TO OCCUR IN THE VICINITY OF
THE SHORTWAVE TROF AND STRONGER Q-G/FRONTOGENETICAL FORCING TO BE
LOCATED TO OUR SOUTH OVER THE MIDWEST. THIS LEAVES THE FNT
INITIALLY TO PROVIDE THE LIFT NECESSARY TO GENERATE PCPN AND THE
LIFT LOOKS WEAK OVER NE WI SUNDAY AFTERNOON. HAVE KEPT A SMALL POP
NEAR THE FNT (N-CNTRL WI) AND KEPT THE REST OF NE WI DRY WITH
INCREASING CLOUDS. PREVAILING SW WINDS WL CONT TO PUMP MODESTLY
WARMER AIR INTO THE AREA WITH MAX TEMPS REACHING AROUND 60 DEGS
N-CNTRL SECTIONS...LWR TO MID 60S ELSEWHERE.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 343 AM CDT SAT SEP 13 2014

THIS FORECAST PERIOD BEGINS WITH AN UPPER LEVEL RIDGE ACROSS THE
WESTERN CONUS AND A BROAD TROUGH IN THE CENTRAL AND EASTERN STATES.

A WEAK SURFACE BOUNDARY IS FORECAST TO PASS THROUGH WISCONSIN
SUNDAY NIGHT INTO MONDAY AND BRING A CHANCE FOR SHOWERS TO THE
AREA. AT THE SAME TIME...THERE WILL BE A COUPLE OF WEAK SHORT
WAVES MOVING THROUGH THE WESTERN GREAT LAKES REGION. MOST OF THE
ENERGY FROM THE NORTHERN SHORT WAVE SHOULD STAY NORTH OF
WISCONSIN...WHILE THE SOUTHERN WILL HAVE MORE IMPACT TO THE
SOUTHWEST OF THE FORECAST AREA.

A LARGE SURFACE HIGH PRESSURE SYSTEM SLOWLY MOVING ACROSS THE
CONUS WILL HELP TO KEEP THINGS MOSTLY RAIN-FREE UNTIL THE END OF
THE WEEK. THERE MAY BE A WEAK SURFACE BOUNDARY AND/OR SOME SHORT
WAVE ENERGY PASSING MAINLY NORTH OF THE STATE...BUT TIMING REMAINS
UNCERTAIN...SO HAVE LEFT THINGS DRY FOR NOW.

UPPER FLOW IS EXPECTED TO BECOME LESS AMPLIFIED AS THE RIDGE
ACROSS THE WEST MOVES EASTWARD...REACHING WISCONSIN BY THE END OF THE
WEEK. A TROUGH TRAILING THE RIDGE...ALONG WITH A SURFACE COLD
FRONT...WILL BRING RAIN CHANCES BACK TO NORTH CENTRAL WISCONSIN ON
FRIDAY AND THE REST OF THE AREA ON FRIDAY NIGHT.

DAYTIME TEMPERATURES SHOULD REMAIN BELOW NORMAL...BUT A SLIGHT
WARMING TREND IS EXPECTED.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1049 PM CDT FRI SEP 12 2014

LIGHT RAIN AND DRIZZLE WILL DEPART TO THE NORTHEAST
OVERNIGHT AS AN UPPER LEVEL DISTURBANCE LIFTS NORTHEAST OF THE
AREA. UNTIL IT DEPARTS...PATCHY MVFR CIGS WILL LINGER OVERNIGHT
OVER NORTHEAST WISCONSIN. ITS LIKELY CLOUDS WILL DIMINISH FROM
WEST TO EAST TONIGHT WITH CLEARING SKIES POSSIBLE. WHERE SKIES
CLEAR THERE IS A GOOD CHANCE OF FROST AND FOG. ANY FOG OR FROST
THAT DOES OCCUR SHOULD END BY 14Z SATURDAY WITH GOOD FLYING
WEATHER EXPECTED SATURDAY INTO SUNDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ005-010>012-
018-019-030-035-036.
&&

$$

SHORT TERM.....KALLAS
LONG TERM......MG
AVIATION.......TDH






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