Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGRB 022017
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
317 PM CDT SAT MAY 2 2015

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 316 PM CDT SAT MAY 2 2015

CHANCES FOR SHOWERS AND STORMS ARE THE MAIN CONCERNS THROUGH
SUNDAY.

SOUTHWEST SURFACE FLOW...BETWEEN HIGH PRESSURE OVER THE OHIO VALLEY
AND LOW PRESSURE FROM THE THE MANITOBA/ONTARIO BORDER INTO THE
NORTHERN U.S. PLAINS...BROUGHT HIGHER TEMPERATURES AND HIGHER DEW
POINTS INTO THE AREA TODAY. 19Z TEMPERATURES AWAY FROM LAKE
MICHIGAN RANGED FROM AROUND 70 DEGREES ACROSS NORTH CENTRAL
WISCONSIN TO NEAR 80 IN PARTS OF CENTRAL WISCONSIN. DEW POINTS
WERE MAINLY IN THE UPPER 30S AND LOWER 40S.

WATER VAPOR SATELLITE IMAGERY SHOWED A POTENT MID LEVEL SHORT WAVE
MOVING ACROSS IOWA. RADAR MOSAIC SHOWED SHOWERS AND ISOLATED
THUNDER ASSOCIATED WITH THIS SYSTEM...AIDED BY SOME WARM ADVECTION.
THE 12Z GFS AND 15Z SREF BROUGHT QPF INTO THE AREA TONIGHT WHILE
THE 12Z ECMWF AND 12Z NAM KEPT IT SOUTH OF THE FORECAST AREA.
SINCE IT DID NOT APPEAR TO BE BUILDING OR MOVING TO THE
NORTH...HAVE NOT INCLUDED ANY POPS TO ACCOUNT FOR THIS FEATURE
TONIGHT.

ATTENTION THEN TURNS TO SUNDAY AS A COLD FRONT APPROACHES FROM THE
NORTHERN PLAINS AND MOVES INTO THE AREA. THE FRONT...COMBINED
WITH WARM ADVECTION AND SBCAPE VALUES MAINLY 1000-2000
J/KG...WILL RESULT IN THE DEVELOPMENT OF THUNDERSTORMS. HAVE
LIKELY OR CATEGORICAL POPS GOING FOR MOST OF THE AREA BY LATE IN
THE AFTERNOON. BEST SHEAR WILL BE ACROSS NORTH CENTRAL WISCONSIN
DURING THE DAY AND SPC INCREASED THE SEVERE RISK FOR SUNDAY
THROUGH SUNDAY NIGHT FROM MARGINAL TO SLIGHT RISK FOR MUCH OF THE
AREA WEST AND NORTHWEST OF THE FOX VALLEY...WITH MARGINAL FOR THE
REST...EXCEPT PART OF MANITOWOC COUNTY. SO...STRONG WINDS AND
LARGE HAIL ARE A POSSIBILITY...ESPECIALLY LATE IN THE DAY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 316 PM CDT SAT MAY 2 2015

PCPN TRENDS WITH SEVERAL FRONTAL SYSTEMS...SEVERE TSTM POTENTIAL
SUNDAY EVENING...AND TEMPERATURES...WILL BE THE MAIN FCST CONCERNS.

TSTMS SHOULD BE ONGOING OVER THE NW TWO-THIRDS OF THE FORECAST AREA
BY EARLY SUNDAY EVENING...AND WILL OVERSPREAD THE REST OF THE
REGION DURING THE EVENING AS A COLD FRONT AND ASSOCIATED MOISTURE
CONVERGENCE MOVES THROUGH. MODERATE INSTABILITY AND DEEP LAYER
SHEAR OF 25 TO 35 KTS WILL SUPPORT A SLIGHT RISK OF SVR TSTMS OVER
NORTH CENTRAL...CENTRAL AND FAR NORTHEAST WI DURING THE EVENING
HOURS. LOCALLY HEAVY RAINFALL IS EXPECTED...AS PRECIPITABLE WATER
VALUES RISE TO AROUND 1.25 INCHES...AND H8 DEW POINTS REACH +10
TO +11 C.

THE FRONT IS EXPECTED TO DROP SOUTH OF THE REGION MONDAY AND
MONDAY NIGHT...WITH HIGH PRESSURE RIDGING ACROSS THE NORTHERN
GREAT LAKES. THIS WILL RESULT IN A MAINLY DRY PERIOD FOR THE
START OF THE NEXT WORK WEEK. AN ELEVATED WARM FRONT IS EXPECTED
TO LIFT BACK INTO THE FORECAST AREA TUESDAY INTO WEDNESDAY...
AND BRING A CHANCE OF SHOWERS AND TSTMS. POPS MAY NEED TO BE
INCREASED DURING THIS PERIOD...ESPECIALLY TUESDAY NIGHT INTO
WEDNESDAY MORNING AS THE STRONGEST BAND OF MOISTURE CONVERGENCE
MOVES THROUGH.

THERE MAY BE A BIT OF A LULL IN THE PCPN CHANCES AFTER THE
WARM FRONT LIFTS NORTH OF THE REGION LATER WEDNESDAY INTO
WEDNESDAY NIGHT...BUT CONFIDENCE IS TOO LOW TO GO WITH A DRY
FCST AT THIS TIME.

PCPN CHANCES SHOULD INCREASE AGAIN OVER THE END OF THE WORK WEEK
AS THE PLAINS LOW AND ASSOCIATED COLD FRONT PUSH INTO THE REGION.
THE FRONT MAY LINGER INTO THE WEEKEND...FOR A CONTINUED CHANCE OF
SHOWERS AND TSTMS.

TEMPERATURES ARE EXPECTED TO BE ABOVE NORMAL FOR MOST OF THE PERIOD.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1237 PM CDT SAT MAY 2 2015

EXPECT VFR CONDITIONS TO PREVAIL OVERNIGHT INTO SUNDAY MORNING.
CANNOT RULE OUT SHOWERS OR THUNDER IN CENTRAL/EAST CENTRAL
WISCONSIN OVERNIGHT...BUT CHANCES AND CONFIDENCE LEVEL ARE TOO LOW
TO INCLUDE IN TAFS. SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG
AND AHEAD OF AN APPROACHING COLD FRONT ON SUNDAY. STILL SOME
DIFFERENCES IN MODEL TIMING BUT AFTERNOON APPEARS TO BE THE MOST
LIKELY TIME FOR STORMS. LATEST SPC CONVECTIVE OUTLOOK FOR SUNDAY
THROUGH SUNDAY NIGHT WAS UPGRADED FROM MARGINAL TO SLIGHT RISK AND
EXPANDED TO INCLUDE MUCH OF THE AREA...SO EXPECT CONDITIONS TO
DETERIORATE BY EARLY SUNDAY AFTERNOON.
&&

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

$$

SHORT TERM.....MG
LONG TERM......KIECKBUSCH
AVIATION.......MG





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.