Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 162242
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
542 PM CDT THU APR 16 2015

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SYNOPSIS...
ISSUED AT 254 PM CDT THU APR 16 2015

CONTINUED MILD AND DRY THE NEXT COUPLE DAYS...THEN SHOWERY AND
TURNING COOLER LATE IN THE WEEKEND AND NEXT WEEK.

THE UPR FLOW ACRS NOAM IS SPLIT...WITH A LOW AMPLITUDE NRN STREAM
ACRS CANADA. A HIGH AMPLITUDE SRN STREAM IS LOCATED ACRS THE
CONUS AND NRN MEXICO...ANCHORED BY A CLOSED UPR LOW OVER THE 4
CORNERS REGION. THE CURRENT PATTERN WL REMAIN IN PLACE THE NEXT
COUPLE DAYS...THEN AS THE NORTHERN STREAM STARTS TO AMPLIFY...THE
SEPARATE BRANCHES WILL BEGIN TO PHASE BACK TOGETHER. THE
AMPLIFICATION WILL CONTINUE NEXT WEEK...EVENTUALLY RESULTING IN A
NEAR BLOCKING REGIME WITH A POSITIVE HEIGHT ANOMALY OVER THE
CANADIAN ARCHIPELAGO...AND A DEEP NEGATIVE ANOMALY TO THE SSE NEAR
THE GREAT LAKES REGION.

THE DRY MILD WEATHER WILL PERSIST THE NEXT COUPLE DAYS AS THE
FORECAST AREA REMAINS NEAR THE SOUTHERN STREAM RIDGE POSITION.
THAT WILL BE FOLLOWED BY A PERIOD OF WET AND COOLER WEATHER LATE
IN THE WEEKEND AND EARLY NEXT WEEK AS THE REMNANTS OF THE SOUTHERN
STREAM CLOSED UPPER LOW SHIFT INTO THE REGION AND BEGIN TO MERGE
BACK WITH THE NORTHERN STREAM. BELOW NORMAL TEMPERATURES ALONG
WITH SOME LIGHT SHOWERS ARE EXPECTED NEXT WEEK AS A DEEP UPPER
TROF DEVELOPS OVER ONTARIO AND THE GREAT LAKES REGION.
&&

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 254 PM CDT THU APR 16 2015

CLOUDS...AND POSSIBLY A FEW LIGHT SHOWERS OR SPRINKLES...IN FAR
EASTERN WISCONSIN MOVED NORTHEAST OVER LAKE MICHIGAN BY EARLY
AFTERNOON. RADAR SHOWED SOME ECHOES MOVING INTO PARTS OF CENTRAL
AND NORTH CENTRAL WISCONSIN TODAY BUT THE AIR WAS QUITE DRY WITH
SURFACE DEW POINT DEPRESSIONS AROUND 30F. THERE WERE NO REPORTS
OF RAIN...AND MOST LOCATIONS DID NOT EVEN REPORT ANY CLOUDS.

A COLD FRONT ACROSS ONTARIO THIS AFTERNOON WILL WEAKEN AS IT
PUSHES SOUTH INTO WISCONSIN. MODELS INDICATED SOME LOW LEVEL
MOISTURE SOUTH OF THE FRONT BUT IT LOOKS LIKE ANOTHER ARID DAY
FARTHER TO THE NORTH. EXPECT AN INCREASE IN CLOUDS AS THE FRONT
MOVES INTO THE AREA BUT MODELS DID NOT HAVE ANY QPF TONIGHT AND
HAD LITTLE OR NOTHING FRIDAY AFTERNOON...SO HAVE CONTINUED WITH A
DRY FORECAST. TEMPERATURES SHOULD BE A BIT WARMER ON FRIDAY AT
MOST LOCATIONS SO HIGHS WELL INLAND FROM LAKE MICHIGAN WILL RANGE
FROM THE UPPER 60S TO MIDDLE 70S.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 254 PM CDT THU APR 16 2015

ONE FINAL DRY DAY IS EXPECTED SATURDAY AS HIGH PRESSURE BUILDS
SEWD TOWARD THE ERN GREAT LAKES REGION. SUBSIDENCE WITH THE HIGH
WL RESULT IN VERY DRY AIR ALOFT FLOWING BACK WWD INTO THE
REGION...AND MIXING INTO THE DRY AIR WILL PROBABLY RESULT IN LOW
AFTERNOON HUMIDITIES.

THE MAIN FCST ISSUES THEN WILL BE THE TIMING OF THE ARRIVAL OF
PRECIPITATION WITH THE EJECTING SOUTHERN STREAM UPPER LOW...AND
PRECIPITATION AMOUNTS WITH THE FEATURE. THE NAM LOOKS TOO FAST
BRUSHING PRECIP THROUGH THE AREA ALREADY SATURDAY...ESPECIALLY
CONSIDERING THE DRY AIR LEFT ON THE WRN FLANK OF THE RECEDING
HIGH. TIMING OF THE MAIN PRECIP CHANCE WITH THE SYSTEM STILL NOT
TOTALLY CLEAR...BUT IT APPEARS THE BEST CHC OF PCPN WILL BE MAINLY
SUNDAY IN THE WEST AND SUN AFTN/NIGHT IN THE EAST. MODEL QPFS ARE
NOT TOO GREAT...BUT SEEM A LITTLE LOW GIVEN THE MOISTURE-RICH
SOUTHERN STREAM SYSTEM HEADING ACRS THE RGN.

A MUCH COOLER PATTERN IS SETTING UP FOR NEXT WEEK. THERE WL BE
SOME SCT SHOWERS AT TIMES...THOUGH AMOUNTS WILL PROBABLY BE RATHER
LIGHT. IT WILL ALSO BE COOL ENOUGH THAT PRECIPITATION TYPE WILL BE
AN ISSUE...ESPECIALLY DURING THE NIGHT. THIS SEEMED ADEQUATELY
HANDLED BY THE BROAD-BASED EXTENDED FORECAST INITIALIZATION
GRIDS...SO NO SIG CHANGES WERE NEEDED.



SKOWRONSKI.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 541 PM CDT THU APR 16 2015

MAINLY VFR CONDITIONS EXPECTED TONIGHT INTO FRIDAY. A FRONTAL
BOUNDARY WILL DROP SOUTHEASTWARD OVER THE STATE TONIGHT INTO
FRIDAY MORNING. SINCE THE AIR MASS IS DRY...EXPECT A BAND OF MID
LEVEL CLOUDS TO BE ASSOCIATED WITH THE FRONT. LIGHT SOUTHWEST
WINDS SHIFTING NORTHWEST WILL MARK THE FRONTS PASSAGE. LATER
FRIDAY...DEEP MIXING MAY PRODUCE A 5 TO 10 MPH WEST WIND BY
FRIDAY AFTERNOON WHILE WINDS REMAIN NORTHEAST TO EAST ALONG LAKE
MICHIGAN FRIDAY AFTERNOON.

&&

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

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....MG
LONG TERM......SKOWRONSKI
AVIATION.......TDH





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