Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 070621
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
121 AM CDT TUE JUL 7 2015

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 250 PM CDT MON JUL 6 2015

THE CONTINUING FCST CHALLENGE REMAINS PCPN TRENDS FOR THE REST OF
THE AFTERNOON INTO THE EVENING HOURS AS CONDITIONS HAVE NOT WORKED
OUT AS ANTICIPIATED.

THE 19Z MSAS SFC ANALYSIS INDICATED THAT A CDFNT EXTENDED FROM
N-CNTRL WI SWWD TO SW WI WITH A STEADY MOVEMENT TO THE EAST. THERE
WAS A SFC WAVE ON THE FRONT LOCATED OVER CNTRL WI AND THIS WAS
HELPING TO GENERATE A CONCENTRATED AREA OF HEAVIER SHWRS OVER
W-CNTRL WI. A BREAK IN THE PCPN OVER THE ERN HALF OF WI HAD
ALLOWED TEMPS TO RECOVER TO AROUND 80 DEGS AND WITH DEW POINTS IN
THE 70S...THE ATMOSPHERE HAS BEGUN TO DESTABILIZE A BIT.

THE FCST HAD PROBLEMS TO BEGIN WITH AS A LARGE CLUSTER OF
SHWRS/TSTMS DEVELOPED OVER THE UPR MS VALLEY LAST NGT AND MOVED
INTO WI THIS MORNING. THIS AREA OF PCPN WEAKENED AS IT REACHED ERN
WI...BUT LEFT A BLANKET OF CLOUDS WHICH INHIBITED FURTHER SHWRS
AND TSTMS FROM DEVELOPING. WL NEED TO WATCH CONDITIONS OVER THE
NEXT COUPLE OF HOURS...HOWEVER THE THREAT OF SEVERE NOW LOOKS
MARGINAL AT BEST WITH LOCALLY HEAVY RAIN THE MAIN THREAT.

THE CDFNT WL EXIT ERN WI THIS EVENING...HOWEVER TRAILING
STRATIFORM LIGHT SHWRS MAY LINGER OVER CNTRL WI TIL AROUND SUNSET
AND ERN WI TIL AROUND MIDNGT. ONCE THE PCPN ENDS...MODELS SHOW
THAT LOW-LEVEL MOISTURE TO LINGER OVER THE AREA THRU MOST OF THE
NGT...THUS A SLOW DECREASE IN CLOUDS CAN BE EXPECTED WITH CLEARING
NOT OCCURRING TIL NEAR DAYBREAK. MIN TEMPS TO RANGE FROM THE UPR
40S N-CNTRL WI...TO THE UPR 50S E-CNTRL WI.

AN AREA OF HI PRES IS FCST TO BUILD INTO THE GREAT LAKES ON TUE
AND BRING COOLER/LESS HUMID AIR TO NE WI. OTHER THAN SOME FAIR
WEATHER CU...MOSTLY SUNNY SKIES ARE EXPECTED WITH DEW POINTS
FALLING INTO THE 40S. MAX TEMPS WL RANGE FROM 65-70 DEGS NORTH/
LAKESHORE...70-75 DEGS SOUTH.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 250 PM CDT MON JUL 6 2015

HIGH PRESSURE WILL BUILD IN FOR THE MIDDLE PART OF THE
WEEK...USHERING IN A DRY COOL AIRMASS ACROSS THE WESTERN GREAT
LAKES. THIS WILL BRING UNSEASONABLY COOL TEMPERATURES TO THE
REGION...MAINLY DURING THE OVERNIGHT HOURS. WITH CLEAR
SKIES...LIGHT WINDS...AND A COOL AIRMASS OVERHEAD OVERNIGHT LOWS
ARE FORECAST TO FALL INTO THE LOW 40S ACROSS NORTH CENTRAL
WISCONSIN. THERE ARE SOME MODELS THAT SUGGEST LOWS COULD EVEN DIP
DOWN INTO THE UPPER 30S...HOWEVER GIVEN THE TIME OF YEAR WILL KEEP
TEMPERATURES A FEW DEGREES WARMER THAN THESE VALUES. TEMPERATURES
THEN SLOWLY START TO MODERATE STARTING WEDNESDAY AS THE HIGH
SHIFTS OFF TO THE EAST AND RETURN FLOW BRINGS WARMER TEMPERATURES
TO THE AREA.

ONE AREA OF CONCERN IS A LOW PRESSURE SYSTEM TRACKING OFF TO THE
SOUTH ON WEDNESDAY NIGHT. CURRENTLY THE NAM IS THE ONLY MODEL THAT
BRINGS THIS LOW FAR ENOUGH NORTH TO BRING RAIN WEDNESDAY NIGHT.
WITH A RIDGE OF HIGH PRESSURE IN PLACE ACROSS THE GREAT LAKES
DURING THIS PERIOD IT DOESN`T SEEM LIKELY THAT THE LOW WOULD
DISPLACE THE HIGH FAR ENOUGH NORTH TO TRACK THROUGH NORTHERN
ILLINOIS PER THE NAM SOLUTION. THEREFORE WILL CONTINUE WITH THE
DRY FORECAST DURING THIS PERIOD WITH THE EXPECTATIONS THE HIGH
WILL WIN OUT IN THE MEDIUM TERM.

THE FORECAST BECOMES A BIT MORE MURKY FARTHER OUT AS A SERIES OF
SHORTWAVES TRACK THROUGH THE GREAT LAKES REGION DURING THE
WEEKEND AND INTO EARLY NEXT WEEK...BRINGING SEVERAL ROUNDS OF
SHOWERS AND THUNDERSTORMS TO NORTHEAST WISCONSIN. AT THIS POINT IT
IS DIFFICULT TO PARSE OUT ANY DRY PERIODS AMONGST THE SEVERAL
ROUNDS OF THIS ACTIVITY...WITH DISCREPANCIES BETWEEN THE MODELS
THEMSELVES OFFERING LITTLE IN THE WAY OF CLARITY. WILL GO WITH
CHANCY POPS DURING THIS PART OF THE FORECAST GIVEN THE MODEL
UNCERTAINTY THIS FAR OUT. THE ATMOSPHERE WILL BECOME WARM AND
JUICY DURING THIS PERIOD...AS DEW POINTS SOAR BACK INTO THE 60S
AND DAYTIME HIGHS GET BACK INTO THE 80S.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 120 AM CDT TUE JUL 7 2015

ISOLATED TO SCATTERED SHOWERS WILL LINGER OVER EAST
CENTRAL WISCONSIN EARLY THIS MORNING OR MAINLY EAST OF THE FOX
RIVER. WHILE CIGS WERE IMPROVING FROM WEST TO EAST OVER MOST AREAS
EXCEPT NORTH CENTRAL WISCONSIN...CLEARING SKIES WERE PRODUCING
MVFR VSBYS DUE TO A COMBINATION OF SMOKE FROM CANADA AND FOG. VFR
CONDITIONS TO EVENTUALLY PREVAIL TUESDAY WITH HIGH PRESSURE
SETTLING INTO THE GREAT LAKES REGION.
&&

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

$$

SHORT TERM.....KALLAS
LONG TERM......KURIMSKI
AVIATION.......TDH


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