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000
FXUS63 KGRB 101744
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1244 PM CDT THU JUL 10 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 345 AM CDT THU JUL 10 2014

FORECAST CONCERNS ARE PCPN CHANCES BY FRIDAY. UNTIL THEN...WEATHER
NIL UNDER HIGH PRESSURE.

SURFACE HIGH MOVING QUICKLY EAST INTO LOWER MI EARLY THIS MORNING.
SOUTHERLY...RETURN FLOW EXPECTED TODAY WITH MOISTURE RAPIDLY
INCREASING AS CURRENT PWATS OF .5 INCREASE TO 1.5 BY FRI
AFTERNOON.

ZONAL UPPER FLOW CONTINUES WITH UPPER TROF SHIFTING EAST INTO
CENTRAL CANADA. SHORT WAVE (MONTANA) IN THE WESTERLIES SOUTH OF LOW TO
MOVES INTO SW MINNESOTA THIS AFTERNOON WEAKENING AS IT MOVES INTO
NW WI TONIGHT. MODELS TRENDING TOWARDS SHOWING PCPN MAXIMIZED IN
TWO AREAS. ONE TO THE SOUTH AND SOUTHWEST OF CWA WHERE LLVL JET
FOCUSED INTO 850 FRONT AND INCREASING DIVERGENT FLOW AS UPPER JET
MOVES EAST INTO STATE. SECOND AREA AHEAD OF SURFACE COLD FRONT OVER
NW WI. HAVE ADJUSTED POPS TO SHOW HIGHER CHANCES OVER SOUTH AND NORTHWEST.

TEMPS TODAY TO WARM TO NEAR NORMAL LEVELS UNDER PARTLY CLOUDY
CONDITIONS. WHILE WAA INCREASES...CLOUDS/PCPN EXPECTED TO HOLD
BACK TEMPS ON FRI.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 345 AM CDT THU JUL 10 2014

THE MAIN STORY IN THE EXTENDED PERIOD TO BE THE AMPLIFICATION OF
THE MEAN FLOW WITH AN UPR RDG BUILDING OVER WRN NOAM AND A
DOWNSTREAM BROAD UPR TROF OVER THE NE QUADRANT OF THE CONUS/ERN
CANADA. UNSETTLED WEATHER EXPECTED OVER NE WI THRU AT LEAST MON
BEFORE THE UPR TROF SHIFTS EAST ADN HI PRES IS ALLOWED TO BUILD
TOWARD THE WRN GREAT LAKES. TEMPS TO BE NEAR NORMAL THIS
WEEKEND...BUT FALL WELL BELOW NORMAL TOWARD THE MIDDLE OF NEXT
WEEK.

INITIAL CHC OF SHWRS ASSOCIATED WITH THE SHORTWAVE TROF SHOULD
TAPER OFF FRI EVENING...HOWEVER THE PASSAGE OF A TRAILING CDFNT
LATER FRI NGT COULD RE-INTRODUCE A SHWR THREAT. INSTABILITY IS
MARGINAL AND WITH GULF INFLOW INTERCEPTED BY A WRMFNT SITUATED
ACROSS THE MIDWEST...PCPN CHCS OVER NE WI AFTER MIDNGT WL BE KEPT
IN THE CHC CATEGORY WITH RELATIVELY LIGHT QPF AMOUNTS. PLENTY OF
CLOUDS/RAIN CHCS/PATCHY FOG WL KEEP TEMPS UP FRI NGT WITH READINGS
IN THE UPR 50S TO LWR 60S.

SAT LOOKS TO BE AN INTERESTING DAY AS THE MEAN FLOW BEGINS TO
AMPLIFY AND THE BROAD UPR TROF BEGINS TO SETTLE SWD TOWARD THE
GREAT LAKES. THE CDFNT IS EXPECTED TO STALL SOMEWHERE OVER NRN IL
AND BE THE PRIMARY FOCAL POINT FOR SHWRS/TSTMS. HOWEVER...AS
COOLER AIR STARTS TO PUSH SOUTH INTO WI AND MID-LEVEL LAPSE RATES
STEEPEN/CAPES RISE TO AROUND 1500 J/KG...WE COULD SEE SHWR/TSTM
ACTIVITY PICK UP...ESPECIALLY DURING THE AFTERNOON HOURS.

THE UPR TROF CONTS TO PUSH INTO THE GREAT LAKES SAT NGT WITH A
SECOND CDFNT MOVING SE AS WELL. MDLS ARE STRUGGLING WITH REGARDS
TO THE SPEED OF THIS CDFNT WITH THE ECMWF/GEM MUCH MORE AGGRESSIVE
THAN THE NAM/GFS. THIS MAKES POP/QPF FCSTS QUITE UNCERTAIN...NOT
TO MENTION THE INSTABILITY PARAMETERS FOR POTENTIAL TSTMS. HAVE
KEPT A CHC POP IN THE FCST FOR NOW AND HOPE THAT THE MDLS CAN GET
INTO BETTER SYNC. MIN TEMPS TO GENERALLY RESIDE IN THE UPR 50S TO
MID 60S. USING A DIPLOMATIC APPROACH FOR THE LOCATION OF THE CDFNT
(ESSENTIALLY SPLITTING THE MDLS)...THIS WOULD SEND THE FNT THRU NE
WI ON SUNDAY WITH ADDITIONAL CHCS FOR SHWRS/TSTMS. INSTABILITY IS
A LITTLE WEAKER ON SUNDAY (COMPARED TO SAT)...BUT THE SHEAR IS
STRONGER. DEPENDING ON EXACTLY WHEN THE FNT ARRIVES AND WHETHER WE
WL BE ABLE TO SEE ANY SUNSHINE...THIS WOULD DETERMINE THE POTENTIAL
FOR ANY OF THESE STORMS TO BECOME STRONG OR EVEN SEVERE. SUNDAY
ALSO LOOKS LIKE THE LAST OF THE `MILD` DAYS WITH MAX TEMPS IN THE
UPR 70S TO LWR 80S.

LOSS OF DAYTIME HEATING SHOULD ALLOW THE PCPN TO BECOME MORE
WIDELY SCATTERED SUNDAY NGT...ONLY TO INCREASE ONCE AGAIN ON MON
AS THE CORE OF THE UPR TROF ROTATES SE INTO THE WRN GREAT LAKES.
8H TEMPS DROP TO AROUND +6C OVER NE WI ON MON...THUS MAX TEMPS MAY
NOT HIT 70S DEGS NORTH...WITH MID 70S OVER E-CNTRL WI. A COOL...
CYCLONIC FLOW TO THEN BE IN PLACE OVER WI MON NGT/TUE AS THE UPR
TROF STARTS TO SHIFT EAST INTO ERN SECTIONS OF ONTARIO AND THE
GREAT LAKES. WL NEED TO KEEP SPOTTY SHWRS IN THE FCST UNTIL THIS
UPR TROF PULLS FAR ENUF AWAY. TUE LOOKS TO BE THE COOLEST DAY OF
THE EXTENDED FCST WITH MAX TEMPS ONLY IN THE LWR 60S NORTH...MID
60S ACROSS CNTRL/E-CNTRL WI. THIS WOULD PLACE READINGS A GOOD 15
TO 20 DEGS BELOW NORMAL!

WE FINALLY CAN SAY GOOD RIDDANCE TO THIS UPR TROF BY NEXT WED...
ALTHO THE MEAN FLOW TO REMAIN FROM THE NW. WEAK HI PRES BUILDING
EAST FROM THE PLAINS SHOULD BRING A GOOD AMOUNT OF SUNSHINE TO THE
REGION WITH MAX TEMPS A BIT WARMER (UPR 60S TO MID 70S).
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1228 PM CDT THU JUL 10 2014

FAIR WEATHER CUMULUS CLOUDS DEVELOPED THIS MORNING AS ANTICIPATED.
WINDS WERE GENERALLY FROM THE SOUTH AT 5 TO 10 KNOTS WILL A FEW GUSTS
TO 15 KNOTS ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. WINDS ALONG
THE BAY AND LAKE WERE FROM THE SOUTHEAST. MAIN ISSUE IS WHEN TO BRING
PRECIPITATION INTO THE REGION ON FRIDAY. MOST OF THE LATEST 12Z MODELS
HAVE SLOWED THE EASTWARD PROGRESS OF THE RAIN...THUS HAVE PUSHED BACK
THE TIMING OF VICINITY SHOWERS IN THE KRHI/KCWA/KAUW. SOME OF THE
MODELS EVEN PUSH THE TIMING OF PRECIPITATION AFTER THE TAF PERIODS
ENDS AT 18Z ON FRIDAY. SOUTH WINDS WILL INCREASE ON FRIDAY...WITH
SOME GUSTS AROUND 20 KNOTS BY LATE FRIDAY MORNING AND AFTERNOON. THE
WIND WILL BE FROM THE SOUTHEAST.

DID ALSO INCLUDE SOME PATCHY FOG AT KMTW LATER TONIGHT DUE TO MOIST
FLOW OFF THE LAKE. CONFIDENCE IS LOW IF THIS WOULD HAPPEN AS WINDS
ARE EXPECTED TO BE SOMEWHAT STRONGER TONIGHT.

 &&

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

$$

SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......ECKBERG