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000
FXUS63 KGRB 091952
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
252 PM CDT SUN MAR 9 2014

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SYNOPSIS...
ISSUED AT 243 PM CDT SUN MAR 9 2014

QUIET WEATHER EXPECTED FOR THE NEXT WEEK...BUT WITH FAIRLY
SUBSTANTIAL SWINGS IN TEMPERATURE.

BROAD BAND OF WESTERLIES WL REMAIN ACRS NOAM THROUGH THE PERIOD.
THE WESTERLIES WL GO THROUGH AT LEAST 1 AMPLIFICATION/
DEAMPLIFICATION CYCLE...AND UNDERGO SOME SPLITTING AT TIMES.

WITH GENERALLY WEAK WX SYSTEMS AFFECTING THE AREA AND GULF
MOISTURE LOCKED AWAY TO OUR S...PCPN AMNTS WL BE BLO NORMAL FOR
THE PERIOD. TEMPS WL BE ON A ROLLERCOASTER RIDE AS CANADIAN AND
MODIFIED PACIFIC AIR VIE FOR CONTROL OF THE FCST AREA. SO DESPITE
CONSIDERABLE WARM/COLD SWINGS...THE WEEK AS A WHOLE WILL PROBABLY
AVERAGE CLOSE TO NORMAL.
&&

.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 243 PM CDT SUN MAR 9 2014

A LACK OF ANY SIGNIFICANT WEATHER SYSTEMS WL PLACE THE MAIN FCST
FOCUS OVER THE NEXT 24 HOURS SQUARELY ON TEMPS AS A MILD AIR MASS
CONTS TO MOVE ACROSS THE REGION.

THE 19Z MSAS SFC ANALYSIS SHOWED ONE AREA OF LOW PRES OVER SW
ONTARIO WITH A SECOND LOW PRES OVER EXTREME NW MN. A CDFNT
CONNECTED THESE LOW PRESSURE SYSTEMS AND CONTINUED THRU THE NRN
PLAINS. A RDG OF HI PRES WAS SITUATED OVER THE OHIO RIVER VALLEY
WITH GUSTY SW WINDS BETWEEN THE THIS HI PRES AND THE TWO SFC LOWS.
VSBL SATL IMAGERY SHOWED A LOT OF MID AND HI CLOUDS FROM THE NRN
PLAINS TO THE GREAT LAKES...WHICH HAS SLOWED THE WARM-UP OF TEMPS
SO FAR TODAY.

MILD PACIFIC AIR WL CONT TO FLOW THRU WI TNGT AS THE AREA OF LOW
PRES MOVES ACROSS SRN CANADA. 8H TEMPS TO RANGE FROM +3 TO +8C
THRU THE NGT AND WITH MID/HI CLOUDS DRIFTING OVERHEAD...WE ARE
LOOKING AT MIN TEMPS ONLY IN THE MID 20S TO LWR 30S. THIS WOULD BE
20 TO 30 DEGS WARMER THAN LAST NGT AND NE WI HAS NOT SEEN
NIGHTTIME TEMPS THIS WARM SINCE MID-JAN.

THE WEAK CDFNT IS FCST TO SWING THRU WI MAINLY ON MON MORNING AND
VEER THE WINDS TO THE WEST. LIFT AND FORCING APPEAR MARGINAL AT
BEST...THUS NO PCPN WL ACCOMPANY THE FRONTAL PASSAGE. THE TOUGHEST
PART OF THE FCST WL BE HOW WARM WE CAN GET BETWEEN THE MILD START
TO THE DAY VERSUS THE ONSET OF WEAK CAA MON AFTERNOON. WHILE THE
MARCH SUN CONTS TO STRENGTHEN WITH EACH PASSING DAY...THE VAST
MAJORITY OF THE FCST AREA STILL HAS A DOUBLE DIGIT SNOWPACK TO
REFLECT THIS SOLAR ENERGY. AS MUCH AS I WOULD LIKE TO THROW 50S
EVERYWHERE IN THE FCST...BELIEVE THAT 45-50 DEGS WOULD BE A GOOD
RANGE FOR MAX TEMPS ON MON...WITH THE CAVEAT BEING THAT AREAS WEST
OF THE FOX VALLEY WL BE ABLE TO SNEAK INTO THE LWR 50S.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 243 PM CDT SUN MAR 9 2014

THE FIRST SUBSTANTIAL ISSUE TO DEAL WITH IN THE LONG TERM IS
PRECIPITATION CHANCES AS BAROCLINIC ZONE SINKS SWD ACRS THE AREA
LATE MON NGT/TUE. MODELS HAVE FLIP-FLOPPED SINCE YDA...WITH THE
NAM NOW WAY S AND THE ECMWF MUCH FARTHER N. GIVEN THE MODEL
DIFFERENCES...IT/S HARD TO ARGUE AGAINST THERE BEING AT LEAST A
CHANCE OF PCPN OVER ABOUT THE SRN 1/3 OF THE FCST AREA. SO STUCK
WITH CHC POPS...BUT DIDN/T WANT TO GO BEYOND THAT. REALLY...ENDED
UP PRETTY CLOSE TO PREV FCST...THOUGH PERHAPS A BIT SLOWER WHICH
ALSO HAS BEEN THE TREND OF THE ECMWF. TEMPS ALOFT WL INITIALLY BE
WARM...BUT THE ATM WL ALSO BE DRY...SO WET-BULB PROFILE SUGGESTS
MAINLY SNOW. IF PRECIPITATION DOES OCCUR...EXPECT IT TO START AS A
MIX OF RN/SN AND MAYBE EVEN SOME ZR BEFORE CHANGING TO ALL SNOW.
BUT SINCE WE DON/T HAVE HIGH CONFIDENCE THAT IT WL EVEN
PRECIPITATE...JUST STUCK WITH A RN/SN MIX IN THE FCST FOR NOW.

EXPECT SCT SHSN TUE NGT AS SHARPENING UPR TROF CROSSES THE AREA.
EDGED POPS ABV GUIDANCE MOST AREAS.

THE MAIN FCST CHG SINCE YDA IS FOR THE PUSH OF COLDER AIR MID-WEEK
TO BE MORE SUBSTANTIAL THAN EARLIER ANTICIPATED. TRENDED TEMPS
DOWN TUE NGT/WED/WED NGT...AND WOULD NOT BE SURPRISED IF LATER
SHIFTS NEED TO ADJUST THEM DOWNWARD FURTHER.

LOOKS LIKE ANOTHER PUSH OF MODIFIED PACIFIC AIR WL DRIVE TEMPS
BACK ABV NORMAL LATE IN THE WEEK BEFORE ANOTHER COOL DOWN OCCURS
NEXT WEEKEND.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1223 PM CDT SUN MAR 9 2014

GUSTY SW WINDS WL CONT THRU THE REMAINDER OF THE
AFTERNOON INTO THE EARLY EVENING HOURS AS THE PRES GRADIENT TO BE
TIGHT BETWEEN RETREATING HI PRES OVER THE OHIO RIVER VALLEY AND AN
AREA OF LOW PRES OVER WRN ONTARIO. EVEN THO WE WL LOSE THE WIND
GUSTS AROUND SUNSET...WINDS JUST ABOVE THE SFC COULD STILL BE
BLOWING AT 30 TO 45 KTS...THUS HAVE INCLUDED SOME LLWS THRU THE
EVENING HOURS. OTHERWISE...EXPECT TO SEE PLENTY OF MID/HI CLOUDS
TNGT INTO MON WITH VFR CONDITIONS TO PREVAIL. ONLY CONCERN COULD
BE THE FORMATION OF SOME LOW CLOUDS ACROSS THE NORTH WHERE ADDED
MOISTURE FROM MELTING SNOW WL COMBINE WITH LIGHTER WINDS. HAVE
KEPT THE RHI TAF SITE VFR FOR NOW...BUT SOMETHING TO WATCH FOR
LATE TNGT.
&&

.HYDROLOGY...
ISSUED AT 243 PM CDT SUN MAR 9 2014

TEMPERATURE FORECASTS GENERALLY IN THE UPR 40S TO LWR 50S ON MON
ARE EXPECTED TO DROP BACK LATE IN THE DAY DUE TO THE PASSAGE OF A
WEAK COLD FRONT. THIS AMOUNT OF WARMING SHOULD PUT A DENT IN THE
DEEP SNOWPACK THROUGH MONDAY. COOLER TEMPERATURES ARRIVE MONDAY
NIGHT THROUGH MID-WEEK TO SLOW DOWN THE MELTING PROCESS. ANY
PROBLEMS FROM THE RUN OFF SHOULD STILL BE CONFINED MAINLY TO
CLOGGED STORM DRAINAGE SYSTEMS ON MONDAY. HOWEVER...SOME PONDING
IN LOW-LYING AREAS IS POSSIBLE. IN ADDITION...RUN OFF WILL ONLY BE
DUE TO SNOW MELT WITH NO ADDITIONAL PRECIPITATION FROM ANY WEATHER
SYSTEMS.

IT WILL LIKELY TAKE A LONGER DURATION SNOW MELT FOR RUN OFF TO
START IMPACTING STREAMS AND RIVERS. AFTER A BRIEF WARM UP AGAIN
THURSDAY AND FRIDAY...COLDER AIR IS FORECAST TO RETURN FOR THE
UPCOMING WEEKEND.
&&

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

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....KALLAS
LONG TERM......SKOWRONSKI
AVIATION.......AK
HYDROLOGY......KALLAS