Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 201100
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
600 AM CDT MON APR 20 2015

UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 400 AM CDT MON APR 20 2015

THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN AREA OF
STRENGTHENING LOW PRESSURE MOVING NORTH OVER SOUTHWEST LOWER
MICHIGAN.  COMMA HEAD PRECIP AROUND THE LOW IS NOW SHIFTING
NORTHWEST AND EXTENDS FROM WAUTOMA TO WAUSAUKEE.  FARTHER
WEST...MID-LEVEL FRONTOGENESIS IS CREATING A BAND OF RAIN OVER
WESTERN WISCONSIN AHEAD OF AN UPPER TROUGH POSITIONED OVER
SOUTH-CENTRAL CANADA AND THE NORTHERN PLAINS.  WINDS SHIFT TO THE
NORTHWEST OVER WESTERN WISCONSIN AND ARE GUSTING INTO THE LOWER 30
KTS.  SOME SNOW BEING REPORTED OVER NORTHERN MINNESOTA AS WELL.  AS
THE LOW CONTINUES TO LIFT TO THE NORTH AND THE UPPER TROUGH SETTLES
OVER THE GREAT LAKES...PRECIP TRENDS ARE THE MAIN FORECAST CONCERN.

TODAY...THE LOW PRESSURE SYSTEM WILL TRAVEL NORTHWARD OVER WESTERN
LOWER MICHIGAN INTO NORTHERN ONTARIO.  MODELS INDICATE THAT COMMA
HEAD PRECIP ASSOCIATED WITH THE LOW WILL LIFT NORTH ACROSS THE
CENTRAL FORECAST AREA EARLY THIS MORNING AND ACROSS THE CENTRAL UPPER
PENINSULA LATER IN THE MORNING.  MEANWHILE...THE FGEN INDUCED RAIN
BAND WILL PIVOT NORTHEAST ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN
THIS MORNING AND NORTHEAST WISCONSIN THIS AFTERNOON.  THEREFORE
EXPECT PERIODS OF RAIN THROUGH THE MORNING...BEFORE THE RAIN
GRADUALLY EXITS TO THE NORTHEAST IN THE AFTERNOON.
ADDITIONALLY...WEST WINDS WILL DRIVE COLDER AIR ACROSS THE STATE
BEHIND THE SYSTEM WHICH WILL STEEPEN LOW LEVEL LAPSE RATES...AND
PROMOTE GUSTY WINDS DEVELOPING.  SOME GUSTS OVER CENTRAL AND
EAST-CENTRAL WISCONSIN COULD EXCEED 30 MPH THIS AFTERNOON.  WITH THE
RAIN AND CLOUDS...COOLER HIGHS IN THE MID 40S TO AROUND 50.

TONIGHT...MID-LEVEL DRY SLOTTING WILL BE ROTATING OVERHEAD DURING
THE EVENING BEFORE DEEPER MOISTURE RETURNS AS UPPER LEVEL LOW
PRESSURE SETTLES ACROSS THE REGION.  MOISTURE WILL BE THE DEEPEST
OVER FAR NORTH-CENTRAL WISCONSIN FOR THE EVENING HOURS...WHERE WILL
CARRY LOW CHANCES OF PRECIP.  THEN PRECIP CHANCES WILL INCREASE FROM
NORTHWEST TO SOUTHEAST THROUGH THE OVERNIGHT.  SOUNDINGS COOL ENOUGH
OVERNIGHT FOR SNOW TO BECOME THE DOMINANT PTYPE OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN FOR MINOR ACCUMULATIONS ON GRASSY SURFACES.
LOWS RANGING FROM THE LOW TO MID 30S.

TUESDAY...WITH UPPER LEVEL LOW PRESSURE OVERHEAD...PERIODS OF RAIN
AND SNOW SHOWERS LOOK TO OCCUR OVER NORTH-CENTRAL WISCONSIN.  MINOR
SNOW ACCUMULATIONS ARE POSSIBLE ACROSS THE NORTH DURING THE
MORNING.  CHANCES OF PRECIP WILL IMPROVE THROUGH THE MORNING OVER
EASTERN WISCONSIN WHERE PRECIP COULD BE A MIX OF RAIN AND SNOW
INITIALLY BEFORE TEMPS RISE WARM ENOUGH FOR ALL RAIN.  COOL WITH
HIGHS RANGING FROM NEAR 40 NORTH TO THE UPPER 40S SOUTHEAST.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 400 AM CDT MON APR 20 2015

UPPER LOW ACROSS ONTARIO WILL GRADUALLY SHIFT EAST INTO QUEBEC BY
THE END OF THE WORK WEEK. COOL CYCLONIC FLOW WILL CONTINUE TO BRING
BELOW NORMAL TEMPERATURES INTO THE WEEKEND...ALONG WITH A CHANCE OF
RAIN OR SNOW SHOWERS AT TIMES TUESDAY NIGHT INTO THURSDAY. HIGHEST
CHANCES WILL BE ACROSS THE NORTH...IN CLOSER PROXIMITY TO THE UPPER
LOW AND SHORTWAVE ENERGY. CURRENT FORECAST IS DRY FOR FRIDAY...
BUT COULD NOT RULE OUT A STRAY RAIN/SNOW SHOWER ACROSS THE NORTH.

DRY CONDITIONS ARE EXPECTED THIS WEEKEND AS HIGH PRESSURE DOMINATES
THE WEATHER PATTERN. ONLY MINOR CHANGES MADE TO MAX/MIN TEMPERATURES
AND PRECIPITATION CHANCES.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 559 AM CDT MON APR 20 2015

STEADY RAIN WITH IFR AND LIFR CIGS WILL END FROM SOUTHWEST TO
NORTHEAST DURING THE AFTERNOON HOURS AS LOW PRESSURE SYSTEM AND
COLD FRONT EXIT THE REGION. AS THE RAIN ENDS...CONDITIONS WILL
EVENTUALLY IMPROVE BACK TO VFR IN THE AFTERNOON. A TIGHT PRESSURE
GRADIENT WILL LEAD TO GUSTY WESTERLY WINDS TODAY. THEN UPPER LEVEL
LOW PRESSURE WILL SETTLE OVER THE REGION TONIGHT WITH RAIN AND
SNOW SHOWERS...AND MVFR CIGS SPREADING SOUTHEAST ACROSS THE TAF
SITES.

&&

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

$$

SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......MPC





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