Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 220752
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
252 AM CDT TUE APR 22 2014

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 252 AM CDT TUE APR 22 2014

DRY AND COOLER WEATHER EXPECTED TODAY BEHIND FRONTAL
SYSTEM THAT MOVED THROUGH YESTERDAY EVENING. COLD ADVECTION IS NOT
THAT IMPRESSIVE BUT ADEQUATE TO KEEP TEMPERATURES AT OR BELOW
SEASONAL NORMALS. CLOUDS SHOULD BE MOSTLY ACROSS NORTH CENTRAL
WISCONSIN WITH NORTHWEST WINDS DOWN SLOPING ACROSS THE REST OF THE
AREA AND HELPING TO KEEP CLOUDS SCATTERED. UPPER RIDGE APPROACHES
TONIGHT AND SURFACE HIGH MOVES RIGHT OVERHEAD. THIS SHOULD MAKE
FOR CLEAR SKIES AND LIGHT WINDS. SNOW COVERED AREAS IN THE FAR
NORTH COULD GET DOWN IN THE UPPER TEENS WITH THE REMAINDER OF THE
REGION IN THE 20S TO NEAR 30. MIDDLE AND HIGH CLOUDS WILL INCREASE
WEDNESDAY AFTERNOON AS COMPLEX SYSTEM APPROACHES FROM THE PLAINS
STATES. MOST OF THE AREA SHOULD REMAIN DRY WITH A CHANCE OF
SHOWERS IN CENTRAL WISCONSIN. SOUTHEAST SURFACE WINDS WILL KEEP
THE LAKE AND BAY AREAS COOLER THAN INLAND AREAS WEDNESDAY.

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 252 AM CDT TUE APR 22 2014

MEAN FLOW IS EXPECTED TO TRANSITION FROM WEAKLY AMPLIFIED/PROGRESSIVE
TO A STRONGLY AMPLIFIED/BLOCKY PATTERN BY NEXT WEEKEND. INITIAL
SYSTEM MOVING ALONG OR JUST SOUTH OF THE CANADIAN BORDER TO IMPACT
NE WI DURING THE WED NGT THRU FRI TIME FRAME AND IS HANDLED SIMILARLY
AMONG THE MDLS. FCST BECOMES MORE COMPLEX AND UNCERTAIN FOR NEXT
WEEKEND AS THE MDLS ATTEMPT TO SHOW A REX BLOCK OVER S-CNTRL CANADA
AND DEEP UPR TROFFING OVER THE ROCKIES. EXACTLY HOW THESE TWO
FEATURES INTERACT WL DETERMINE PCPN POTENTIAL FOR NEXT SUNDAY AND
MON. TEMPS ARE EXPECTED TO BE BELOW NORMAL THRU THE ENTIRE EXTENDED
FCST.

A STRONG/SLIGHTLY NEGATIVELY-TILTED UPR TROF IS FCST TO MOVE INTO
THE PLAINS WED NGT AND HELP TO ENHANCE AN AREA OF LOW PRES TO MOVE
FROM THE CNTRL PLAINS TO THE MIDWEST. AN INCREASING SOUTHERLY LOW-
LEVEL JET OF 40 TO 50 KTS WL BRING WARMER/MORE MOIST AIR MASS
QUICKLY NWD...AS WELL AS LIFT A WRMFNT WHICH IS EXPECTED TO REACH
NE IA/CNTRL IL BY 12Z THU. STRONG SURGE OF ISEN LIFT TO TAKE PLACE
TO OUR WEST AND WHEN YOU ADD A COUPLED JET STRUCTURE FOR ADDED
LIFT...WE SHOULD SEE RAIN SHWRS GRADUALLY OVERSPREAD MOST OF NE WI
WED NGT. WL HAVE TO WATCH NRN WI AS TEMPS DIP INTO THE LWR TO MID
30S AND THE POTENTIAL FOR A LITTLE SNOW TO MIX WITH THE RAIN.

THE UPR TROF SWEEPS INTO THE UPR MS VALLEY/MIDWEST ON THU WITH
MODERATE MID-LEVEL FORCING PUSHING INTO WI. MEANWHILE...THE SFC
LOW IS PROGGED TO LIFT NE INTO SW WI WITH THE WRMFNT REACHING SRN
WI. CONTINUED WAA AND FAVORABLE JET DYNAMICS...COMBINED WITH
PLENTY OF LOW-LEVEL MOISTURE TO BE IN PLACE WITH PW VALUES
APPROACHING 1 INCH...WL LEAD TO A RAINY DAY ACROSS ALL OF NE WI
WITH LOCALLY HEAVY RAINFALL POSSIBLE. NOT OVERLY IMPRESSED WITH
THE THUNDER POTENTIAL ON THU AS CAPES ARE MINIMAL AND LI`S ONLY
FALL INTO THE LWR SINGLE DIGITS ABOVE ZERO. PREFER TO TONE DOWN
THE THUNDER THREAT WITH THE CHCS OF SVR STORMS VERY LOW AT BEST.
MAX TEMPS TO BE HELD IN CHECK BY ALL THE CLDS/RAIN...THUS MID TO
UPR 40S NORTH...LWR TO MID 50S SOUTH WL HAVE TO DO.

SHWR ACTIVITY TO CONT THRU AT LEAST THU EVENING AS THE SFC LOW
LIFTS NE AND AN ATTENDANT CDFNT PUSHES THRU WI. THE UPR TROF ALSO
LIFTS NE THRU WI AND EVENTUALLY CLOSES OFF INTO A LARGE/MODEST UPR
LOW BY 12Z FRI. SOME QUESTIONS REMAIN FOR THU NGT INCLUDING WHEN
(IF) THE PCPN ENDS AND IF IT DOESN`T END...COULD SNOW MIX IN
ACROSS THE NORTH AS TEMPS BEGIN TO FALL? CAN`T SEE THE PCPN
COMPLETELY SHUTTING DOWN...ESPECIALLY OVER THE NORTH IN PROXIMITY
TO THE UPR TROF. HAVE ADDED A MIX TO THE FCST FOR FAR NRN WI AFTER
MIDNGT...BUT NO ACCUMULATION WORDING AS GROUND TEMPS HAVE WARMED.
THIS SYSTEM WL CONT TO PLAGUE NE WI THRU FRI AS A TRIALING
SHORTWAVE TROF/SECONDARY CDFNT MOVE THRU THE WRN GREAT LAKES.
MIXED PCPN OVER N-CNTRL WI MAY LINGER INTO FRI MORNING BEFORE
TRANSITIONING TO ALL RAIN AS TEMPS CLIMB INTO THE 40S. OTHERWISE...
ANOTHER CLDY DAY WITH CHC POPS NECESSARY AND TEMPS 5 TO 15 DEGS
BELOW NORMAL.

WE FINALLY GET RID OF THIS SYSTEM FRI NGT WITH WEAK SFC RIDGING TO
BUILD ACROSS THE UPR MS VALLEY. THAT BEING SAID...WL HAVE TO WATCH
N-CNTRL WI FOR POTENTIAL LAKE EFFECT AS COLD NORTH WINDS MOVE OVER
LAKE SUPERIOR. MEAN FLOW BEGINS TO AMPLIFY BY SAT AS A DEEP UPR
TROF MOVES ACROSS THE WRN CONUS AND DOWNSTREAM UPR RIDGING TAKES
PLACE OVER THE CNTRL CONUS. THE SFC RDG AXIS TO REACH THE GREAT
LAKES ON SAT WITH MOSTLY SUNNY TO PARTLY CLDY SKIES AND TEMPS A
GOOD 10 TO 15 DEGS BELOW NORMAL.

MAIN POINT OF CONTENTION FOR EARLY NEXT WEEK WL BE THE INTERACTION
BETWEEN THE DEEP UPR TROF (OR CLOSED UPR LOW) OVER THE CNTRL PLAINS
AND THE NEARLY CLOSED UPR HI (REX BLOCK) OVER S-CNTRL CANADA. AN
ACTIVE QUASI-STNRY FRONTAL BOUNDARY TO BE SITUATED OVER THE MID-MS/
OHIO RIVER VALLEY REGIONS AND BE THE PRIMARY FOCAL POINT FOR PCPN.
EXACTLY HOW FAR NORTH THIS PCPN CAN GET WITH A DRY NE WIND OVER WI
WL BE A FCST HEADACHE FOR DAYS TO COME. HAVE KEPT SUNDAY DRY WITH
THE DRY/BLUSTERY NE WINDS DOMINATING. EVEN SUNDAY NGT/MON LOOK
PRIMARILY DRY ALTHO SRN SECTIONS OF THE FCST AREA MAY NEED A SMALL
POP BY THEN AS THE PCPN TRIES TO EDGE CLOSER.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1031 PM CDT MON APR 21 2014

LOW CLDS HAVE PUSHED SWD INTO FAR NRN WI. BUT EXPECT THAT ANY
ADDITIONAL SWD PUSH WL BE LIMITED. WL KEEP LOW CLDS WITH LOW-END
VFR/HIGH-END MVFR CIGS IN N-C WI...BUT BACK OFF ON EXPANDING THEM
SWD ACRS THE AREA.
&&

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

$$

SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......SKOWRONSKI






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