Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 241955
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
255 PM CDT THU APR 24 2014

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 255 PM CDT THU APR 24 2014

PROGRESSIVE PATTERN OVER REGION THIS PERIOD...AS TROF OVER CENTRAL
PLAINS SWEEPS THROUGH THE REGION. DIFLUENT FLOW ALOFT AND STRONG
WAA MAINTAINING WIDESPREAD PRECIPITATION OVER THE REGION THIS
AFTERNOON. TEMPERATURES NOT CLIMBING TOO FAST OVER FAR NORTHERN
WI...WITH SNOW STILL BEING SEEN OVER PARTS OF NORTH CENTRAL WI.
SNOW IS ONLY ACCUMULATING ON GRASSY SURFACES IF AT ALL. WAA TO
CONTINUE AND WILL LIMIT ANY FURTHER ACCUMULATION THIS EVENING. TWO
PIECES OF TROF MAKING WAY TOWARDS AREA...STRONG SHORT WAVE OVER
KS/MO REGION AND NORTHERN SHORTWAVE OVER DAKOTAS. LARGE AREA OF
SHOWERS WITH FIRST SYSTEM TO MAKE WAY TOWARDS EASTERN CWA.
NORTHERN SHORT WAVE EXPECTED TO MOVE THROUGH AROUND
MIDNIGHT...BRINGING AN END TO THE PRECIPITATION TONIGHT FROM WEST
TO EAST..

FRI MAY BE THE TRICKY PART OF THE FORECAST. CYCLONIC FLOW
CONTINUES OVER REGION...WITH MODELS SHOWING MID LEVELS REMAINING
UNSTABLE. QUESTION IS TEMPS. STRONG SUBSIDENCE BEHIND NORTHERN
WAVE SHOULD CLEAR THINGS OUT IN THE EARLY MORNING...THOUGH IS
EXPECTED TO CLOUD OVER AGAIN FAIRLY QUICKLY WITH RESIDUAL MOISTURE
AND COLD AIR ALOFT. WITH OFFSHORE FLOW AND RELATIVELY WARM LLVL
TEMPS WILL SEE NEAR NORMAL TEMPS SOUTH...THOUGH CONTINUED BELOW
NORMAL NORTH WITH MORE CLOUDS...HIGHER CHANCE OF SHOWERS. NO
CHANGE IN THOUGHTS OF ISOLD TO SCATTERED SHOWERS FOR FRI.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 255 PM CDT THU APR 24 2014

LONG TERM FCST BECOMES COMPLICATED AFTER SATURDAY...AS A HIGHLY
AMPLIFIED PATTERN DEVELOPS AND A LONG PERIOD OF UNSETTLED WEATHER
SETS UP OVER WISCONSIN...WITH SEVERAL CHANCES FOR RAIN AND
POSSIBLY SOME SNOW TO THE NORTH FOR THE CWA. OVERALL...A WET AND
COOL PATTERN IS PREDICTED BEGINNING SATURDAY NIGHT AND CONTINUING
THROUGH THE BEGINNING OF NEXT WEEK.

LETS START WITH THE MORE STRAIGHT FORWARD PORTION ON THE FCST
PERIOD...FRIDAY NIGHT AND SATURDAY. LOW PRESSURE WILL BE PASSING
NORTH OF WISCONSIN THROUGH LAKE SUPERIOR FRIDAY NIGHT. A COLD
FRONT ALONG WITH SOME ENERGY FROM THIS SYSTEM WILL BRUSH NORTHERN
WISCONSIN AS IS MOVES EAST. THIS WILL BRING A CHANCE FOR LIGHT
RAIN OR SNOW TO THE FAR NORTH...MAINLY THROUGH MIDNIGHT. SOME OF
THE MODELS HINT AT SOME PCPN FURTHER SOUTH...HOWEVER TRIED TO
CONFINE POPS TO THE VICINITY OF THE FRONT AND BEST VORTICITY
ADVECTION TO THE NORTH. AFTER MIDNIGHT...HIGH PRESSURE WILL BUILD
SOUTH INTO THE STATE OUT OF CANADA...RESULTING IN DRY AND MOSTLY
SUNNY CONDITIONS DEVELOPING ON SATURDAY WITH COOL TEMPERATURES AS
STRONG NW FLOW ALOFT AND CAA SETS UP OVER THE AREA. DROPPED HIGH
TEMPERATURES A FEW DEGREES ON SATURDAY AS MANY MODELS CAME IN COLDER
FOR 12Z RUN.

THE SYNOPTIC PATTERN WILL THEN BECOME MORE AMPLIFIED SATURDAY
INTO SATURDAY NIGHT AS AN UPPER LVL TROUGH DIGS INTO THE WESTERN
US AND A RIDGE BUILDS TO OUR EAST. IN ADDITION...A DEEPENING LOW
PRESSURE SYSTEM DEVELOPS TO THE LEE OF THE ROCKIES ON SATURDAY.
WITH SOUTHERLY WINDS DEVELOPING OVER THE CENTRAL US...PLENTIFUL
MOISTURE OUT OF THE GULF WILL BE AVAILABLE AS THIS SYSTEM DRIFTS
NORTH AND EAST TOWARDS WISCONSIN SATURDAY NIGHT. MODELS STRUGGLE
WITH THIS TIMING AND PRECIP PLACEMENT ASSOCIATED WITH THIS
SYSTEM.

AS A RESULT...STARTING SATURDAY NIGHT...FCST BECOMES
MUDDLED...MAKING IT DIFFICULT TO ADD ANY DETAILS TO THE OVERALL
PATTERN...WHICH WOULD BE AN EXTENDED PERIOD OF RAIN WITH POSSIBLY
SOME SNOW OVERNIGHTS IN THE NORTH. DO NOT THINK THERE WILL BE
PRECIP FOR DAYS ON END CONTINUOUSLY...HOWEVER IT IS NOT POSSIBLE
TO DELINEATE DRY PERIODS FROM WET PERIODS AT THIS TIME. TRIED TO
ADD SOME DETAIL TO SUNDAY...AS MODELS HAVE TRENDED TOWARDS A
SIMILAR SOLUTION...WITH AN 850MB WARM FRONT SITTING OVER SOUTHERN
WISCONSIN BY 12Z SUN WHICH PUSHES NORTHWARD. RAIN WILL OVERSPREAD
THE REGION THROUGH THE DAY AS THIS FRONT MOVES NORTH. FAVORED THE
SLOWER TIMING OF PRECIP ARRIVAL AS THERE IS ABUNDANT DRY AIR TO
OVERCOME AT LOW LEVELS...AND MODELS SEEM TO BE TRENDING SLOWER
WITH NORTHWARD PUSH OF THE FRONT. STRONG FORCING WILL BE IN PLACE
OVER THE AREA...WITH THE RRQ OF AN UPPER LEVEL JET...STRONG
VORTICITY...AND FGEN CO- LOCATED IN THE VICINITY OF THE WARM FRONT
SUNDAY AFTERNOON THROUGH CENTRAL AND EAST- CENTRAL WISCONSIN.
TRIED TO HIGHLIGHT THE BEST CHANCES FOR POPS HERE SUNDAY LATE
AFTERNOON INTO SUNDAY NIGHT.

RAIN WILL CONTINUE THROUGH THE BEGINNING OF THE WEEK WITH TIMING
AND AMOUNTS DEPENDENT ON THE MOVEMENT OF THE LOW THAT WILL SLOWLY
DRIFT TOWARDS THE GREAT LAKES REGION. MODELS SHOW THIS SYSTEM
REACHING SOUTHERN WISCONSIN MONDAY AND THEN SHIFTING EAST BEFORE
BECOMING NEARLY STATIONARY BY LATE TUESDAY AS A BLOCKING PATTERN
SETS UP. THE LOW SITTING OVER THE IN/IL AREA FOR A EXTENDED
PERIOD OF TIME AND THROWING CHANCES OF RAIN OUR WAY AS PIECES OF
CIRCULATE AROUND THE CLOSED UPPER LEVEL LOW. OVERALL...BELOW NORMAL
TEMPERATURES AND WET WEATHER IS EXPECTED MONDAY THROUGH THURSDAY.
MAINLY RAIN CAN BE EXPECTED...WITH SOME SNOW POSSIBLE OVER
NORTHERN WISCONSIN WITH ANY PRECIP THAT FALLS THROUGH THE
OVERNIGHT PERIODS.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1235 PM CDT THU APR 24 2014

LOW PRESSURE IN THE PLAINS TO SEND WAVES OF PCPN INTO WESTERN
LAKES. DRY AIR IN PLACE OVER THE REGION THIS MORNING HAS COMBINED
WITH TEMPS IN THE 30S TO PRODUCE SOME WET SNOW FOR FEW HOURS AT
START OF PCPN. NOT SEEING ANY ACCUMULATION. EXPECT ALL TO SWITCH
OVER TO ALL RAIN AS WARM ADVECTION CONTINUES OVER THE STATE. FINAL
PIECE OF ENERGY MOVES THROUGH THIS EVENING OUT OF THE PLAINS
TAKING BULK OF PCPN OUT OF REGION BY MORNING. CYCLONIC FLOW AND
INSTABILITY ON FRI WILL LEAD TO SCATTERED SHOWER ACTIVITY AND
CLOUDS THROUGH MUCH OF DAY...ESPECIALLY OVER THE NORTH.
&&

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

$$

SHORT TERM.....TE
LONG TERM......WOLF
AVIATION.......TE






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