Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 211936
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
236 PM CDT THU AUG 21 2014

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 235 PM CDT THU AUG 21 2014

IN THE NEAR-TERM...FIRST BATCH OF RAIN ASSOCIATED WITH DECAYING
CONVECTIVE SYSTEM MOVED OUT OF FORECAST AREA DURING THE EARLY
AFTERNOON. CONSIDERABLE CLOUDS BEHIND SYSTEM INHIBITING ATMOSPHERE
FROM DESTABILIZING. ANY ADDITIONAL CONVECTION WILL BE TIED TO
UPPER LEVEL SHORTWAVE TROF THAT TOPS THE RIDGE AS IT MOVES ACROSS
MN INTO N WI TONIGHT. WHILE ADDITIONAL DEVELOPMENT CANNOT BE RULED
OUT ASSOCIATED WITH SURFACE FRONT THAT IS SUPPRESSED A BIT TO THE
SOUTH OF THE FORECAST AREA...THINK BETTER CHANCE FOR DEVELOPMENT MAY
BE IN THE NW HALF OF THE AREA...WHICH WOULD THEN SLIDE EAST OVERNIGHT.

FORCING THEN WANES LATER TNGT AS THE SHORTWAVE TROF SHIFTS E AND 850
MB FLOW VEERS WLY. UPR HEIGHTS ACRS THE AREA BUILD FRIDAY AND
UPPER FLOW BECOMES INCREASINGLY ANTICYCLONIC. HARD TO ABSOLUTELY
RULE OUT PRECIP GIVEN THE AVAILABLE MOISTURE AND POSSIBLE
BOUNDARIES ACRS THE REGION...THOUGH LARGE SCALE FORCING IS
DEFINITELY UNFAVORABLE. WILL KEEP VERY SMALL CHANCE/ISOLATED POPS.

TEMP FORECAST IS A BLEND OF PREVIOUS FORECAST AND BEST PERFORMING
SHORT-TERM GUIDANCE.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 235 PM CDT THU AUG 21 2014

FRIDAY NIGHT INTO SATURDAY...PROGS IN GOOD AGREEMENT WITH THE
UPPER RIDGE BUILDING OVER THE WESTERN GREAT LAKES REGION. MODELS
ARE PRODUCING SPOTTY QPF IN THE WARM AND MOIST AIR MASS BUT WILL
CONTINUE WITH LOW END CHC POPS OR NO MEASURABLE POPS FOR THIS
STRETCH. MAIN FRONTAL SYSTEM WITH DEEP MOISTURE SAGS SOUTH OF THE
AREA STARTING FRIDAY NIGHT.

THE UPPER RIDGE IS PROGGED TO NUDGE EAST A LITTLE SATURDAY AS A
CLOSED LOW OR DEEP UPPER TROUGH DRIFTS INTO THE NORTHERN AND
CENTRAL PLAINS. H850 LLJ AHEAD OF THIS NEXT SYSTEM STARTS TO LIFT
A DEEP MOISTURE AND A MORE UNSTABLE AIR MASS OVER MINNESOTA AND
FAR WESTERN WISCONSIN LATER SATURDAY AND ESPECIALLY SATURDAY NIGHT
INTO SUNDAY. POPS WILL TEND TO BE HIGHER TO THE WEST SATURDAY AND
SATURDAY NIGHT AND EVEN PERHAPS SUNDAY...WITH THE UPPER RIDGE
PROTECTING EASTERN AREAS.

UPPER SYSTEM TRACKING OVER SOUTHERN CANADA SUNDAY NIGHT INTO
MONDAY NIGHT WILL DRAG A COLD FRONT OVER THE AREA. WHILE TIMING
ISSUES REMAIN WITH THIS FROPA PASSAGE...THE SLOW PROGRESSION
SUPPORTS A PCPN MENTIONED FOR SEVERAL PERIODS THROUGH MONDAY.

DEEPER AND MORE UNSTABLE AIR MASS GETS SHOVED SOUTH MONDAY NIGHT
INTO TUESDAY FOR ANOTHER PERIOD OF LOW END POPS. BUT PRECIP
CHANCES WILL RETURN NEXT WEEK WITH A SERIES OF COLD FRONT
PASSAGES ASSOCIATED WITH THE UPPER TROUGH SYSTEM OVER SOUTHERN
CANADA AND THE NORTHERN GREAT LAKES REGION. A DEVELOPING
BAROCLINIC ZONE MAY INTERACT WITH THE UPPER JET DYNAMICS FOR A FEW
PERIODS OF RAIN MID WEEK.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1230 PM CDT THU AUG 21 2014

WIDESPREAD MVFR AND IFR CLOUDS INTO EARLY AFTERNOON WITH
BREAKS POSSIBLE BEHIND DECAYING CONVECTIVE SYSTEM MOVING ACROSS
CENTRAL AND EAST-CENTRAL WI. ADDITIONAL CONVECTION LATE THIS
AFTERNOON/EVE ASSOCIATED WITH MAIN SYSTEM.
&&

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

$$

SHORT TERM.....JKL
LONG TERM......TDH
AVIATION.......JKL





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