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000
FXUS63 KGRB 141743
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1243 PM CDT FRI JUN 14 2013

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 352 AM CDT FRI JUN 14 2013

SURFACE HIGH CENTERED OVER NORTHERN WISCONSIN WILL
BRING BEAUTIFUL WEATHER TO THE AREA TODAY BEFORE EDGING TO THE
EAST TONIGHT. LOW DEW POINTS AND SINKING AIR SHOULD KEEP THINGS DRY
TODAY WITH JUST AN INCREASE IN HIGH CLOUDS THIS AFTERNOON. AN
OCCLUDED FRONT WILL APPROACH FROM MINNESOTA LATE TONIGHT AND BRING
SHOWERS AND ELEVATED THUNDERSTORMS. BEST LOW LEVEL WARM ADVECTION
IS TO OUR SOUTH WHILE BEST UPPER SUPPORT IS TO THE NORTH. HIGHEST
PRECIPITATION TOTALS SHOULD BE IN CENTRAL WISCONSIN. THE FRONT IS
FORECAST TO MOVE ACROSS WISCONSIN SATURDAY BUT THERE IS LITTLE
SUPPORT FOR PRECIPITATION DUE TO DRY MID LEVEL AIR AND A CAPPING
INVERSION. WILL KEEP A CHANCE OF THUNDERSTORMS FOR NOW.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 352 AM CDT FRI JUN 14 2013

THE MEDIUM RANGE MODELS TONIGHT CONTINUE TO HAVE THEIR
DIFFERENCES WITH THEIR TIMING OF A POSITIVELY TILTED SHORTWAVE
ACROSS THE REGION LATE THIS WEEKEND. THE ECMWF HAS BEEN THE MOST
CONSISTENT MODEL WITH THIS FEATURE...AND HAS SUPPORT FROM THE SREF
SO WILL CONTINUE TO STICK WITH IT FOR THE MASS FIELDS.
HOWEVER...MODELS ARE STRUGGLING WITH THEIR PRECIP FIELDS AS
WELL...MOST LIKELY DUE TO THEIR HANDLING OF CONVECTION ACROSS THE
REGION. WILL MAKE SOME HAND EDITS TO POPS BASED ON THE LOCATION OF
THE PROJECTED FORCING. BY THE MIDDLE OF NEXT WEEK...THE GFS IS
CONSIDERABLY MORE PROGRESSIVE WITH THE EASTWARD MOTION OF THE MID-
LEVEL RIDGE...WHILE THE ECMWF IS MORE AMPLIFIED AND SLOWER. GIVEN
THE AMPLIFIED NATURE OF THE PATTERN TO BEGIN WITH...SLOWER IS
PROBABLY BETTER.

SATURDAY NIGHT THROUGH SUNDAY NIGHT...A CLOSED UPPER LOW WILL BE
SPINNING OVER THE LAKE WINNIPEG REGION AS SHORTWAVE ENERGY EJECTS
OUT OF THIS LOW OVER SOUTHERN ONTARIO ON SATURDAY NIGHT.  AS THIS
OCCURS...STILL SEEING EVIDENCE OF WEAK SHORTWAVE IMPULSES MOVING
WEST TO EAST ACROSS THE SOUTHERN GREAT LAKES...PLACING NORTHERN
WISCONSIN BETWEEN THESE TWO AREAS OF FORCING.  REGARDLESS...THE
RIGHT REAR QUAD OF THE UPPER JET STREAK WILL BE PASSING OVER CENTRAL
AND SOUTHERN WISCONSIN WHERE THERE IS MODEST ELEVATED INSTABILITY.
WILL PUT HIGHEST POPS OVER THIS AREA...BUT NORTHERN WISCONSIN COULD
STILL SEE SCT SHOWERS AND THUNDERSTORMS.  PRECIP CHANCES WILL EXIT
OVERNIGHT AS A WEAK COLD FRONT PASSES ACROSS THE AREA.  LOW PRESSURE
WILL MOVE INTO THE LAKE SUPERIOR REGION ON SUNDAY...BUT PLENTY OF
DRY AIR ALOFT AHEAD OF IT.  WILL REMOVE PRECIP CHANCES.  THE
SOUTHERN CANADA SHORTWAVE THEN SWINGS ACROSS THE REGION ON SUNDAY
NIGHT.  LIGHT PRECIP CHANCES WILL RETURN BUT CANNOT FIND MUCH
INSTABILITY.  WILL DIMINISH THUNDER CHANCES.  HIGHS ON SUNDAY IN THE
UPPER 70S TO MID 80S.  LOWS IN THE 50S AND 60S FOR BOTH NIGHTS.

REST OF THE FORECAST...WILL LINGER SMALL PRECIP CHANCES OVER NE
WISCONSIN MONDAY MORNING UNTIL THE SHORTWAVE EXITS.  THEN CANADIAN
HIGH PRESSURE BUILDS INTO THE REGION FOR THE SECOND HALF OF MONDAY
AND WILL LINGER THROUGH AT LEAST WEDNESDAY AND MOST LIKELY INTO
THURSDAY AS WELL.  SOME RIPPLES WILL BE PASSING OVERHEAD DURING THIS
PERIOD WITHIN THE NW FLOW...BUT THE AIRMASS IS QUITE DRY SO WILL
TREAT THIS MORE AS A SHORT TERM CONCERN.  TEMPERATURES WILL BE
COOLING INTO THE LOW TO MID 70S MONDAY AND TUESDAY...AND THEN WILL BE
GRADUALLY WARMING THEREAFTER.  WILL LOWER HIGHS ON MONDAY.
&&

.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.....RDM
LONG TERM......MPC
AVIATION.......BERSCH