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 280843
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
343 AM CDT THU MAY 28 2015

FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SYNOPSIS...
ISSUED AT 336 AM CDT THU MAY 28 2015

QUITE WARM TODAY...THEN ANOTHER ROUND OF WET WEATHER FRIDAY INTO
FRIDAY NIGHT.

THE MAIN WESTERLIES ARE ACRS CANADA...WITH A WEAKER BUT ENERGETIC
SRN STREAM ACRS THE CONUS. THE DEGREE OF SEPARATION OF THE
STREAMS WL TEMPORARILY DECREASE THE NEXT FEW DAYS AS STG NRN
STREAM SHRTWV SWINGS THROUGH SRN CANADA...AND DRAWS IN SOME SRN
STREAM ENERGY. BUT THE SPLIT IS EXPECTED TO RE-EMERGE NEXT WK...
WITH SRN STREAM UPR TROF POSN NR THE WEST COAST AND BROAD RIDGING
DOWNSTREAM OVER THE CONUS.

THIS IS A PRETTY TYPICAL EARLY SUMMERTIME PATTERN. TEMPERATURES
WL START OUT ABV NORMAL...FALL TO BELOW NORMAL LEVELS FOR THE
WEEKEND AS THE NRN STREAM SHRTWV DRAGS A COOL ANTICYCLONE SEWD
INTO GREAT LAKES RGN FM NWRN CANADA...THEN WARM BACK TO ABV NORMAL
BY THE MIDDLE OF NEXT WEEK. THE PROXIMITY OF THE SRN STREAM WL
RESULT IN AMPLE MOISTURE AND SEVERAL OPPORTUNITIES FOR PCPN...SO
AMNTS ARE LIKELY TO END UP ABV NORMAL FOR THE PERIOD.
&&

.SHORT TERM...TODAY...TONIGHT...AND FRIDAY
ISSUED AT 336 AM CDT THU MAY 28 2015

WK FRONTAL BOUNDARY HAS SAGGED INTO THE NRN PART OF THE FCST
AREA. WITH MAINLY CLR SKIES AND A WK SFC PRESSURE GRADIENT...FOG
HAS FORMED OVER MUCH OF THE AREA. THE FOG WL LINGER THROUGH
DAYBREAK...THEN SHOULD BURN OFF QUICKLY. HIGH CLDS FM THE WEST WL
PROBABLY STREAM ACRS THE AREA...BUT ARE LIKELY TO BE THIN. THAT
SHOULD ALLOW FOR PLENTY OF SUN...AT LEAST UNTIL CONVECTIVE
TEMPERATURES ARE REACHED...AT WHICH POINT SOME CU WL BEGIN TO
FORM. MOST MODELS GENERATED SCT PCPN DURING THE AFTN OVER E-C TO
NE WI...WITH INITIATION POSSIBLY AIDED BY CONVERGENCE ALONG THE
LAKE BREEZE FRONT. GIVEN THE EASE WITH WHICH CONVECTION FIRED YDA
AFTN AND THE INSTABILITY ON MODEL FCST SOUNDINGS...IT SEEMS
REASONABLE TO EXPECT ISOLD-SCT SHRA/TSRA TO DEVELOP AGAIN TDA.
THE GREATEST COVERAGE SHOULD BE OVER NE WI...NR THE RETREATING
FRONTAL BOUNDARY. STUCK CLOSE TO PREV FCST FOR MAX TEMPS.

THE CONVECTION OVER ERN WI SHOULD DECR/END THIS EVENING. MODELS
WERE IN AGREEMENT IN SLOWING THE EWD ADVANCE OF THE PCPN FM THE W.
SO TRIMMED POPS BACK FM PREV FCST. ERN WI COULD VERY WELL REMAIN
DRY THROUGH THE NGT AFTER ANY EVENING SHRA DISSIPATE.

PCPN SHOULD OVERSPREAD THE AREA FRI. AS THE FCST STANDS NOW...CLDS
SHOULD BE IN PLACE BY DAYBREAK FRI AND PCPN IS EXPECTED TO
OVERSPREAD THE REMAINDER OF THE AREA DURING THE MORNING. THAT
WOULD GREATLY LIMIT DESTABILIZATION...MITIGATING THE SVR THREAT.
SPC HAS A MARGINAL RISK OF SVR OVER ABOUT THE SERN 1/4 OF THE FCST
AREA...AND THAT SEEMS REASONABLE GIVEN THE ABOVE SCENARIO. BUT
AFTER MAKING MAJOR CHANGES TO PCPN TIMING WITH THIS FCST...IT/S
HARD TO HAVE GREAT CONFIDENCE THAT WE/VE SUDDENLY GOT IT ALL
FIGURED OUT. IF FURTHER SLOWING OF THE CLDS AND PCPN BECOMES
NECESSARY...IT WOULD ALLOW FOR MORE SIG DESTABILIZATION TO
OCCUR FRI...AND RESULT IN AN INCREASED RISK OF SVR STORMS.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 336 AM CDT THU MAY 28 2015

MAIN FCST FOCUS TO BE ON THE FRI NGT/SAT MORNING PCPN CHCS/AMOUNTS
AS A CDFNT TO CONT SLOWLY MOVING SOUTH AWAY FROM THE REGION.
OTHERWISE...GENERALLY QUIET AND COOL CONDITIONS EXPECTED FOR THE
WEEKEND BEFORE TEMPS GRADUALLY WARM NEXT WEEK. NEXT PCPN CHC AFTER
SAT MORNING MAY NOT OCCUR UNTIL THE MIDDLE OF NEXT WEEK AT THE
EARLIEST. THIS SHOULD ALLOW RIVERS THAT ARE CURRENTLY RUNNING HIGH
TO DROP WITHIN BANKFULL.

THERE ARE STILL SOME TIMING DIFFERENCES AMONG THE MODELS WITH
RESPECT TO HOW FAST THE CDFNT WL EXIT THE REGION FRI NGT. NAM/
ECMWF ARE SLOWER WITH THE FNT ONLY REACHING THE WI/IL BORDER BY
12Z SAT...WHILE THE GFS/GEM ARE THE FASTEST WITH THE FNT PUSHING
TOWARD CNTRL WI. THIS DIFFERENCE WL EVENTUALLY DETERMINE HOW LONG
TO HANG ON TO PCPN ACROSS THE NORTH FRI NGT AND CNTRL/E-CNTRL WI
HEADED INTO SAT. HAVE HEDGED THE FCST TOWARD THE NAM/ECMWF MAINLY
DUE TO A SFC WAVE MOVING ALONG THE CDFNT THAT WOULD THE SLOW THE
FNT`S SE PROGRESS. THEREFORE...FAIRLY HIGH POPS EXPECTED FRI
EVENING BEFORE THE PCPN BEGINS TO DIMINISH OVER N-CNTRL WI LATER
FRI NGT. AN ADDITIONAL ONE-QUARTER TO ONE-HALF INCH OF RAIN IS
POSSIBLE ACROSS CNTRL/E-CNTRL WI FRI NGT WHICH COULD ALLOW SOME
AREA RIVERS TO APPROACH FLOOD STAGE. HAVE RAISED MIN TEMPS A
COUPLE OF DEGS WITH A 40-45 DEG RANGE NORTH...UPR 40S TO LWR 50S
SOUTH.

AFTER SOME LINGERING SHWR CHCS SAT MORNING ACROSS E-CNTRL WI...
EXPECT TO SEE DECREASING CLOUDS ACROSS THE FCST AREA AS AN AREA OF
HI PRES SETTLES OVER ONTARIO. DRIER/COOLER AIR MASS TO PUSH INTO
WI ON GUSTY NORTH WINDS WITH A NOTICEABLE DROP IN TEMPS COMPARED
TO READINGS SEEN EARLIER IN THE WEEK. LOOK FOR MAX TEMPS TO RANGE
FROM THE MID TO UPR 50S NEAR LAKE MI...UPR 50S TO AROUND 60 DEGS
NORTH AND LWR TO MID 60S CNTRL/E-CNTRL WI.

THE BROAD AREA OF HI PRES IS FCST TO SETTLE INTO SRN ONTARIO/NRN
GREAT LAKES SAT NGT BRINGING RATHER CHILLY CONDITIONS TO THE FCST
AREA. UNDER MAINLY CLEAR SKIES AND DIMINISHING E-NE WINDS...THE
THREAT OF FROST BECOMES AN ISSUE ESPECIALLY OVER NRN WI WHERE
WINDS WL BE THE LIGHTEST. WL CONT TO HIT THE FROST THREAT IN THE
HWO AS MIN TEMPS DIP INTO THE UPR 20S TO LWR 30S NORTH...MID TO
UPR 30S CNTRL/E-CNTRL AND AROUND 40 DEGS NEAR LAKE MI. THE SFC HI
REMAINS ANCHORED FROM THE NRN SECTIONS OF THE GREAT LAKES INTO SE
CANADA ON SUNDAY...PROMISING PLENTY OF SUNSHINE AND A MODEST E-SE
WIND AT 5 TO 15 MPH. TEMPS WL CONT TO RUN BELOW NORMAL BY 5 TO 10
DEGS WITH READINGS SIMILAR TO SAT.

AS THE SFC HI BEGINS TO SLIDE TOWARD THE CANADIAN MARITIMES/NE
CONUS ON MON...NE WI TO REMAIN ON THE WRN FRINGE OF THE HI PRES...
THUS A CONTINUED STRETCH OF DRY WEATHER WITH A GRADUAL MODERATION
IN TEMPS. AFTER ANOTHER COOL NGT (SUNDAY NGT)...MAX TEMPS FOR MON
ARE FCST TO REACH AROUND 60 DEGS LAKESIDE...MID TO UPR 60S
ELSEWHERE.

QUIET CONDITIONS TO PREVAIL MON NGT/TUE AS THE GREAT LAKES REGION
TO RESIDE BETWEEN THE RETREATING SFC HI TO THE EAST AND A BROAD
UPR TROF OVER THE WRN CONUS. WINDS ARE EXPECTED TO VEER TO THE
SOUTH AND ALLOW FOR WEAK WAA TO OVERSPREAD WI. THIS WAA WL HAVE
ENUF LIFT TO GENERATE MORE CLOUDS...BUT NOT STRONG ENUF TO PRODUCE
ANY PCPN. MAX TEMPS ON TUE WL RISE INTO THE MID 60S ALONG LAKE
MI...LWR 70S NORTH AND MID 70S SOUTH.

TOWARD THE MIDDLE OF NEXT WEEK...A BLOCKY PATTERN TO BE IN PLAY
WITH THE WRN CONUS UPR TROF AND A BROAD UPR RDG SITUATED JUST OFF
THE SE CONUS COAST. THIS WOULD BRING A SW FLOW ALOFT INTO WI WITH
INCREASING TEMPS AND MOISTURE. THE PRIMARY CDFNT IS PROGGED TO
STILL BE LOCATED TO OUR WEST ON WED...BUT WITH A MODERATELY
UNSTABLE AIR MASS OVER THE STATE...ANY SHORTWAVE OR POTENTIAL LAKE
BREEZE BOUNDARY MAY BE ENUF TO KICK OFF A FEW SHWRS OR TSTMS. NOT
VERY CONFIDENT THIS FAR OUT ON PCPN POTENTIAL AND WOULD PREFER TO
KEEP ANY POPS RATHER LOW. MORE CONFIDENT ON THE CONTINUED WARMING
WITH MAX TEMPS FOR WED RANGING FROM THE UPR 60S NEAR LAKE MI...MID
70S N-CNTRL WI AND UPR 70S TO LWR 80S ELSEWHERE.
&&

.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 336 AM CDT THU MAY 28 2015

FOG WILL LEAD TO QUITE VARIABLE AND LOCALLY VERY POOR FLIGHT
CONDITIONS EARLY THIS MORNING. BUT ONCE THAT BURNS OFF AFTER
SUNRISE...GENERALLY GOOD FLIGHT CONDITIONS ARE EXPECTED FOR THE
REST OF TDA AND MUCH OF TNGT...WITH THE EXCEPTION OF ANY ISOLD-SCT
SHRA/TSRA THAT DEVELOP THIS AFTN.
&&

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

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......KALLAS
AVIATION.......SKOWRONSKI



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