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000
FXUS63 KGRB 141941
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
241 PM CDT FRI JUN 14 2013

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 240 PM CDT FRI JUN 14 2013

VERY PLEASANT DAY IN NORTHEAST WI WITH ONLY SOME MIDDLE AND UPPER
LEVEL CLOUDS DRIFTING ACROSS THE AREA. THE QUIET WEATHER WILL COME
TO AN END FOR SOME TONIGHT AS SURFACE HIGH PRESSURE PUSHES EAST
OF THE AREA...AND A FRONTAL SYSTEM AND SHORTWAVE APPROACH FROM THE
NORTHERN PLAINS. SHOWERS AND STORMS WILL CONTINUE TO DEVELOP
ACROSS IOWA AND MINNESOTA IN RESPONSE TO WARM AIR ADVECTION AND A
LOW LEVEL JET NOISING INTO THAT AREA. THIS ACTIVITY WILL PUSH OVER
CENTRAL AND NORTH CENTRAL WI AREA LATER TONIGHT...MAINLY AFTER
MIDNIGHT. THUNDER THREAT WILL CONTINUE OVERNIGHT...AS MOST OF THE
ACTIVITY WILL BE ELEVATED...TAPPING INTO SOME INSTABILITY ALOFT AND
STEEPER LAPSE RATES. STRONGEST WARM AIR ADVECTION AND LOW LEVEL
JET ENERGY WILL REMAIN SOUTH OF THE AREA...CLOSER TO SOUTHERN
WI...IOWA...AND NORTHERN ILLINOIS...SO EXPECT THE MAJORITY OF THE
THUNDERSTORMS TO REMAIN THERE. A COMPLEX COULD FORM IF THE
ACTIVITY IS ABLE TO ORGANIZE OVERNIGHT. WILL KEEP THE HIGHEST POPS
ACROSS CENTRAL WI...WITH LOWER POPS EAST AS DRIER AIR IS IN PLACE
AND IT IS FARTHER AWAY FROM THE DYNAMICS.

THE FRONT WILL CROSS THE AREA ON SATURDAY...AS THE BEST UPPER
LEVEL SUPPORT ARRIVES AS A JET PUSHES ACROSS THE REGION.
HOWEVER...PLENTY OF CLOUDS ARE EXPECTED...SO INSTABILITY SHOULD
REMAIN IN CHECK...AND SOME DRIER AIR WILL MOVE INTO THE MID-
LEVELS. SUBSIDENCE FROM ANY COMPLEX AND/OR CONVECTION TO OUR SOUTH
PREVENTING ENOUGH MOISTURE TO RETURN INTO THE AREA COULD PUT A
DAMPER ON ADDITIONAL DEVELOPMENT. SO NOT THE BEST SET UP FOR
ANOTHER ROUND OF SHOWERS AND STORMS...BUT PREFER TO KEEP A CHANCE
IN THE FORECAST. DID NOT MAKE ANY MAJOR CHANGES TO TEMPS...WITH
NEAR SEASONAL READINGS EXPECTED.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 240 PM CDT FRI JUN 14 2013

BASIC UPPER PATTERN CONSISTS OF TROFS OVER THE EAST AND WEST
COASTS WITH FLAT RIDGE OVER CENTRAL U.S. AS CLOSED LOW SHIFTS
EAST THROUGH SOUTHERN CANADA. PATTERN TO BECOME MORE AMPLIFIED
ONCE AGAIN NEXT WEEK AS RIDGE BUILDS OVER CENTRAL U.S. FOR TUE
ONWARD. STAYED WITH BASICALLY DRY FORECAST GIVEN MUCH UNCERTAINTY
WITH ANY WAVES MOVING THROUGH NW FLOW OVER STATE. TEMPERATURES
EXPECTED TO BE AT OR SLIGHTLY ABOVE SEASONAL NORMS.

SATURDAY NIGHT...A WEAK COLD FRONT WILL BE MOVING THROUGH EASTERN
WI. WEAK WAVE/S MOVING THROUGH WESTERLY FLOW SOUTH OF CANADIAN
LOW AND ASSOCIATED CONVECTION THE QUESTION. WHERE AND WHEN THIS WILL
OCCUR VERY UNCERTAIN. GIVEN EXPECTED LOCATION OF FRONT AND
MOISTURE HAVE TRENDED TOWARDS GFS/EC SOLUTIONS HIGHLIGHTING
SOUTHERN HALF OF CWA.

DRY AIR MASS/WESTERLY WINDS ON SUNDAY BEHIND FRONT TO BRING WARM
AND MOSTLY SUNNY DAY FOR FATHERS DAY.

MODELS STILL SHOWING DIFFERENCES ON SPEED AND DEPTH OF MAIN WAVE
EXPECTED TO PASS SUNDAY NIGHT INTO MONDAY. ALL HAVE IT EAST OF THE
STATE BY 00Z TUE SO TRENDED TOWARD DRY FORECAST MONDAY NIGHT. BEST
FORCING SUN NIGHT AND MON TO THE NORTH LEADING TO HIGHER POPS
THERE SUNDAY NIGHT. SOME DIFFERENCES IN AVAILABLE INSTABILITY WITH
NAM MORE ENERGETIC. HAVE STAYED CLOSE TO PREVIOUS FORECAST AND
CHANCE POPS.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1243 PM CDT FRI JUN 14 2013

MID/HIGH LEVEL CLOUDS WILL CONTINUE TO SLOWLY INVADE AND THICKEN
OVER THE AREA FROM THE WEST THIS AFTERNOON AND EVENING...AS A A
FRONTAL SYSTEM APPROACHES. THIS SYSTEM WILL SPREAD THE CHANCE
FOR SHOWERS AND A FEW THUNDERSTORMS ACROSS THE AREA
TONIGHT...ESPECIALLY OVER CENTRAL AND NORTH CENTRAL WISCONSIN.
BECAUSE OF THE UNCERTAINTY REGARDING HOW WIDESPREAD THE ACTIVITY
WILL BE...WILL ONLY HAVE A TEMPO GROUP FOR SHOWERS DURING THE
09-13Z PERIOD FOR RHI/AUW/CWA...HOWEVER THAT DOES NOT COMPLETELY
RULE OUT A SHOWER BEFORE THIS PERIOD. FARTHER EAST...A LOWER
CHANCE OF SHOWERS (OR A STORM) EXISTS DUE TO DRIER AIR...SO WILL
HANG ON TO THE PROB30 FROM THE PREVIOUS FORECAST. NOT ENOUGH
CONFIDENCE TO ADD THUNDER...HOWEVER IT MAY BE ADDED IN LATER
FORECASTS. THE FRONT WILL WEAKEN AS IT CROSSES THE AREA
SATURDAY...HOWEVER IT WILL KEEP THE CHANCE FOR SHOWERS OR
THUNDERSTORMS ACROSS THE AREA DURING THE AFTERNOON HOURS. NOT
ENOUGH CONFIDENCE ON DEVELOPMENT...SO WILL LEAVE OUT OF THE TAFS
AT THIS POINT.
&&

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

$$

SHORT TERM.....BERSCH
LONG TERM......TE
AVIATION.......BERSCH