Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 251800
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
100 PM CDT SAT JUL 25 2015

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 243 AM CDT SAT JUL 25 2015

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL END BY SUNRISE
AHEAD OF A WEAK COLD FRONT MOVING ACROSS THE AREA. THE AIR BEHIND
IT IS NOT MUCH COOLER THAN THE AIR AHEAD OF IT BUT IT IS A LITTLE
DRIER. SKIES SHOULD BECOME MOSTLY SUNNY WITH HIGHS AROUND FIVE
DEGREES ABOVE USUAL FOR THIS TIME OF THE YEAR.

CLEAR SKIES EXPECTED TONIGHT WITH GROUND FOG POSSIBLE IN THE USUAL
LOCATIONS. LOWS TONIGHT WILL BE PRETTY CLOSE TO SEASONAL NORMALS.

SUNDAY SHOULD BE SUNNY AND SLIGHTLY WARMER. HIGHS WILL BE IN THE
MIDDLE TO UPPER 80S WITH COOLER TEMPERATURES ALONG RIGHT ALONG THE
LAKESHORE.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 243 AM CDT SAT JUL 25 2015

THE MEAN FLOW WL UNDERGO SOME MODIFICATION NEXT WEEK AS A RATHER
STRONG UPR-LVL TROF MOVES FROM THE NW CONUS E-NE ALONG THE NRN
TIER OF STATES/SRN CANADA. AHEAD OF THIS SYSTEM...THERE REMAINS
UNCERTAINTY AS TO PCPN CHCS AS AN UPR RDG TO RESIDE OVER THE
E-CNTRL CONUS WITH WEAK DISTURBANCES MOVING ACROSS THE TOP OF THIS
RDG. VERY WARM AND HUMID CONDITIONS WL ALSO EXIST...SO IT WOULD
NOT TAKE MUCH TO POP UP A FEW SHWRS OR TSTMS IN THIS AIR MASS. THE
BEST LIKELIHOOD FOR SEEING A MORE WIDESPREAD RAINFALL WOULD BE TUE
NGT INTO WED MORNING ASSOCIATED WITH THE PASSAGE OF A CDFNT...
ALONG WITH THE UPR TROF MOVING BY TO OUR NORTH. THE UPR RDG IS
THEN EXPECTED TO SHIFT TOWARD THE WRN CONUS...BRINGING A NW FLOW
TO NE WI. SLIGHTLY COOLER/LESS HUMID CONDITIONS TO PREVAIL FOR
LATE NEXT WEEK.

AS MENTIONED ABOVE...THERE IS STILL PLENTY OF UNCERTAINTY DURING
THE SUNDAY NGT/MON TIME PERIOD AS THE SFC HI BEGINS TO PULL AWAY
AND ALLOWS FOR A RETURN FLOW/ONSET OF WAA TO MOVE INTO WI. EVEN
THO THE UPR RDG IS POKING INTO THE GREAT LAKES...THERE ARE SUBTLE
DISTURBANCES MOVING ON THE FRINGE OF THIS RDG AND SOME OF THE
MODELS INSIST THAT A FEW SHWRS OR TSTMS COULD DEVELOP OVER PARTS
OF THE STATE. OTHER MODELS KEEP THE HI PRES CLOSE ENUF TO PREVENT
ANY PCPN FROM REACHING ERN WI THRU 00Z TUE. PREFER TO KEEP SOME
CONTINUITY TO THE FCST AND KEEP A MINIMAL POP FOR MOST OF THE FCST
AREA DUE TO THE WEAKNESS OF THE UPR RDG PLUS INCREASED INSTABILITY
AS MAX TEMPS ON MON RANGE FROM THE LWR 80S NEAR LAKE MI...TO THE
MID TO UPR 80S ELSEWHERE.

AS THE UPR TROF MOVES ACROSS THE NRN ROCKIES TOWARD THE NRN PLAINS
MON NGT INTO TUE...A CDFNT IS EXPECTED TO PUSH INTO THE UPR MS
VALLEY. A PREVAILING SOUTHERLY WIND INTO WI WL HELP TO LIFT A SFC
WRMFNT INTO THE GREAT LAKES BRINGING A SURGE OF ISEN LIFT. ONCE
AGAIN...IT APPEARS THAT PCPN COVERAGE WOULD BE SPOTTY WITH MANY
DRY HOURS FOR BOTH MON NGT AND TUE. AFTER A MILD NGT WITH MIN
TEMPS IN THE MID TO UPR 60S...IT IS POSSIBLE FOR MAX TEMPS ON TUE
TO APPROACH THE 90 DEG MARK OVER PARTS OF CNTRL/E-CNTRL WI IF THE
PCPN CAN STAY AWAY.

THE BEST CHC FOR SEEING A WIDESPREAD RAINFALL APPEARS TO BE TUE
NGT WITH THE PASSAGE OF THE CDFNT. WAY TOO EARLY TO DETERMINE
WHETHER ANY OF THESE TSTMS WOULD HAVE THE POTENTIAL OF TURNING
SEVERE. THERE WL BE GOOD INSTABILITY...HOWEVER SHEAR VALUES ARE
WEAK AND STRONGER FORCING WOULD BE FOCUSED CLOSER TO THE UPR TROF
(TO OUR NORTH AND WEST). THE SHWR/TSTM THREAT MAY LINGER INTO WED
MORNING...ESPECIALLY OVER ERN WI UNTIL THE CDFNT CLEARS THE AREA.
ONCE THE FNT DEPARTS...DRIER AIR IS FCST TO SWEEP INTO WI WITH DEW
POINTS FALLING THRU THE DAY. THE WARM START TO WED (MID 60S TO LWR
70S) WL ALLOW MAX TEMPS TO REACH THE LWR 80S N-CNTRL WI...UPR 80S
E-CNTRL WI (AWAY FROM LAKE MI).

AN AREA OF HI PRES IS FCST TO BUILD FROM THE CNTRL PLAINS INTO THE
GREAT LAKES BY THU AND BRING PLEASANT/SEASONAL CONDITIONS TO THE
FCST AREA. MAX TEMPS THU WL BE CLOSER TO NORMAL WITH READINGS IN
THE UPR 70S TO LWR 80S. AFTER A QUIET THU NGT...LONG-RANGE MODELS
SEND A WEAK CDFNT INTO WI ON FRI. WL MAINTAIN A SMALL POP OVER
PARTS OF THE FCST AREA FOR NOW...ALTHO MOISTURE AVAILABILITY MAY
BE AN ISSUE AS GULF MOISTURE LOOKS TO BE CUT-OFF BY A FRONTAL
BOUNDARY DRAPED ALONG THE GULF COAST STATES. MAX TEMPS ON FRI
SHOULD BE CLOSE TO THOSE SEEN ON THU (PERHAPS A DEG OR TWO WARMER)
WHICH TRANLATES TO MORE UPR 70S TO LWR 80S.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1258 PM CDT SAT JUL 25 2015

AREAS OF MVFR CIGS AND LOW END VFR CIGS IN EAST CENTRAL WISCONSIN
SHOULD EXIT THE AREA THIS AFTERNOON AS DRIER AIR ARRIVES. DEW
POINTS AT 17Z WERE IN THE 65 TO 70F RANGE FROM WAUTOMA...TO
OSHKOSH AND MANITOWOC...BUT ONLY IN THE MID AND UPPER 50S FROM
CENTRAL WISCONSIN EAST INTO THE SHAWANO AREA. EXPECT LIGHT WINDS
UNDER HIGH PRESSURE. THERE WERE AREAS OF DENSE FOG THIS MORNING UNDER
THE SURFACE HIGH...MAINLY IN NORTHWEST WISCONSIN AND MINNESOTA.
THE PREVIOUS TAFS MENTIONED FOG AND HAVE OPTED TO KEEP IT EVEN
THOUGH 12Z MET AND 12Z MAV GUIDANCE INDICATING LITTLE OR NO FOG.
&&

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

$$

SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......MG


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