000
FXUS63 KGRB 091723
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1223 PM CDT SUN MAR 9 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND MONDAY
ISSUED AT 351 AM CDT SUN MAR 9 2014

TYPICAL THIS EARLY MARCH WITH THE DEEP SNOW PACK...TEMPS HAVE FALLEN
INTO THE SINGLE DIGITS WHERE WINDS HAVE CALMED EARLY THIS
MORNING...A FEW SPOTS PROBABLY DROPPING BELOW ZERO. AFTER THE COLD
START THIS MORNING...STRONG WAA DEVELOPING TODAY AND CONTINUING INTO
MONDAY WILL PROVIDE A WELCOMED TEMP CHALLENGE...MAX TEMPERATURES.

MAINLY HIGH LEVEL CLOUDS WILL PASS OVER THE AREA TODAY INTO
TONIGHT AS A LOW PRESSURE SYSTEM TRACKS NORTH OF THE AREA. SOME
MIDDLE LEVEL CLOUDS WILL PASS OVER THIS MORNING. THESE CLOUDS WERE
ASSOCIATED WITH A WARM FRONT PASSING OVER THE NORTHERN GREAT
LAKES REGION TODAY. DLH RADAR IS PICKING UP SOME RETURNS IN THE
ARROWHEAD REGION EARLY THIS MORNING AND WILL MONITOR DEVELOPMENT
THIS MORNING FOR POSSIBLE SMALL MENTION OF PCPN ACROSS THE FAR
NORTH AND NORTHEAST AS THE WARM FRONT PASSES.

THE FOCUS TURNS TO TEMPERATURE FORECASTS AND TRENDS AS THE WAA
INCREASES LATE TODAY AND TONIGHT. H850 TEMPS CLIMBING TO +6 C BY
LATE AFTERNOON THIS AFTERNOON AND NEAR +8 C MONDAY MORNING BEFORE
TAPERING BACK MONDAY AS A COOL FRONT SLIDES OVER. RATHER LARGE
WARM LAYER FROM 925 MP TO 800 MB WILL BE BATTLING THE COLD
BOUNDARY CONDITIONS...BUT MANY TIMES BETTER MIXING OCCURS WITH THE
PASSAGE OF A COOL FRONT TO ALLOW THE WARMER AIR TO REACH THE
SURFACE AS WILL BE THE CASE ON MONDAY. IN ADDITION A FEW PROGS
INDICATE 925 TEMPS REMAIN AROUND +9 DURING THE BETTER MIXING
PERIOD ON MONDAY WHICH SUPPORTS WELL INTO THE 50S. OTHER
VARIABLES WHICH COULD AFFECT TEMPS WILL BE AMOUNT OF CLOUDS AND
THEN MONDAY MORNING TEMPS IN REGARDS TO THE WARM INITIAL START.
THE GFS MODEL WAS PRODUCING A FEW LIGHT AMOUNTS MONDAY AFTERNOON
SO A BIT MORE CLOUDS MAY PUT SOME DAMPER ON MONDAYS HIGHS.
ANTICIPATE FURTHER ADJUSTMENTS TO TEMP TRENDS THE NEXT FEW DAYS
WILL BE REQUIRED.

WITH A BRISK WEST WIND FOR MONDAY...DO NOT ANTICIPATE USING A
COOLER BY THE LAKE WORDING JUST YET.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
ISSUED AT 351 AM CDT SUN MAR 9 2014

NO MAJOR SYSTEMS TO DEAL WITH FOR THE REMAINDER OF THE WORK WEEK.
THE LATEST ECMWF WOULD SUGGEST CLIPPER SYSTEM FOR NEXT SATURDAY
ALTHOUGH GFS BRINGS THIS SYSTEM WELL SOUTH OF THE AREA. TEMPERATURES
THIS WEEK WILL BE ON THE TYPICAL SPRING ROLLER COASTER RIDE WITH
SEVERAL DAYS AT OR ABOVE NORMAL AND A FEW DAYS WITH BELOW NORMAL
TEMPERATURES.

FOR MONDAY NIGHT...HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN.
SYSTEM BREWING IN THE CENTRAL AND SOUTHERN PLAINS WILL CAUSE SNOW
TO FORM ACROSS NEBRASKA AND SOUTH DAKOTA AND THEN SPREAD EAST INTO
MINNESOTA AFTER MIDNIGHT. THE SYSTEM SHOULD PASS WELL SOUTH OF THE
STATE ON TUESDAY. TEMPERATURES SHOULD STILL BE FAIRLY SEASONABLE
WITH HIGHS IN THE MIDDLE 30S TO LOWER 40S. THE CANADIAN/ECMWF HAD
PRECIPITATION FURTHER NORTH THAN THE GFS/WRF. SINCE STILL A FEW
DAYS OUT...TOOK A COMPROMISE BETWEEN THESE TWO SOLUTIONS WHICH WAS
PRETTY MUCH WHAT WAS IN THE CURRENT FORECAST FOR THIS PERIOD.

ADDED WRINKLE FOR TUESDAY NIGHT WAS TO ADD A SLIGHT CHANCE OF SNOW
SHOWERS WITH COLD FRONT THAT SHOULD PUSH SLOWLY SOUTHWEST ACROSS
THE FORECAST AREA. LATER SHIFTS MAY NEED TO BUMP UP SNOW CHANCES WITH
THIS FEATURE. SOME MODELS DID LINGER THE FRONT ACROSS CENTRAL WISCONSIN
WEDNESDAY MORNING...THUS SMALL CHANCES FOR SNOW SHOWERS IN THIS PORTION
OF THE FORECAST AREA. IT WILL BE COLD ON WEDNESDAY WITH HIGHS IN THE
20S.

ATTENTION THEN TURNS TO THURSDAY WITH FAIRLY DECENT 850MB WARM ADVECTION.
ECMWF/CANADIAN ARE SIMILAR IN SHOWING BAND OF PRECIPITATION MOVING ACROSS
THE AREA THURSDAY MORNING INTO THURSDAY AFTERNOON. THERMAL PROFILES
WOULD INDICATE PRECIPITATION WOULD START AS SNOW...THEN THEN POSSIBLY
TRANSITION INTO RAIN OR FREEZING RAIN DEPENDING ON HOW BOUNDARY LAYER
TEMPERATURES RESPOND LATER THURSDAY MORNING AND THURSDAY AFTERNOON.
HAVE 20ISH PERCENT CHANCES FOR PRECIPITATION AT THE MOMENT...BUT COULD
SEE LATER SHIFTS INCREASING THEM EVEN MORE. FRIDAY WILL BE SEASONABLE
WITH HIGHS IN THE MIDDLE 30S TO LOWER 40S...THEN TURN COLDER FOR NEXT
SATURDAY. BASED ON 00Z MODELS TONIGHT...PROBABLY AT LEAST SEVERAL
DEGREES TOO WARM FOR HIGHS ON SATURDAY. PLENTY OF TIME FOR THE MODELS
TO CHANGE ITS TUNE ON HOW MUCH COLD AIR WILL WORK INTO THE REGION...
THUS WILL PASS ON MY CONCERN TO THE DAY SHIFT.
&&

.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 351 AM CDT SUN MAR 9 2014

TEMPERATURE FORECASTS FOR TODAY INTO MONDAY HAVE
TRENDED A BIT WARMER THE LAST FEW DAYS...WITH SOME OF THE WARMER
BIAS LOCATIONS POSSIBLY REACHING OR JUST EXCEEDING THE 50 DEGREE
MARK MONDAY BEFORE TAPERING BACK LATE IN THE DAY DUE TO A COOL
FRONT PASSAGE. WITH TEMPS RISING TO NEAR 40 TODAY...OVERNIGHT LOWS
FALLING TO JUST NEAR FREEZING AND THEN A RUN WELL INTO THE 40S TO
NEAR 50 MONDAY...THIS WILL PUT A GOOD DENT IN THE DEEP SNOWPACK
THROUGH MONDAY. COOLER TEMPERATURES ARRIVE MONDAY NIGHT THROUGH
MID WEEK TO SLOW DOWN THE PROCESS. ANY PROBLEMS FROM THE RUN OFF
SHOULD STILL BE CONFINED TO CLOGGED STORM DRAINAGE SYSTEMS ON
MONDAY BUT RUN OFF WILL BE A BIT MORE...WITH SOME PONDING IN LOW
LYING AREAS POSSIBLE. IN ADDITION RUN OFF WILL BE ONLY DUE TO SNOW
MELT WITH NO ADDITION FROM ANY WEATHER SYSTEM.

IT WILL LIKELY TAKE A LONGER DURATION SNOW MELT FOR RUN OFF TO
START IMPACTING STREAMS AND RIVERS. AFTER A BRIEF WARM UP AGAIN
THIS THURSDAY...LOOKS COLD THROUGH THIS WEEKEND.
&&

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

$$

SHORT TERM.....TDH
LONG TERM......ECKBERG
AVIATION.......AK
HYDROLOGY......TDH