Area Forecast Discussion
Issued by NWS Green Bay, WI

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780
FXUS63 KGRB 151749
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1249 PM CDT FRI MAY 15 2015

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 402 AM CDT FRI MAY 15 2015

THE UPPER TROUGH THAT BROUGHT US SHOWERS OVERNIGHT WILL EXIT THE
REGION AROUND DAYBREAK THOUGH A FEW LIGHT SHOWERS OR SPRINKLES MAY
LINGER THROUGH MIDDAY. WEAK UPPER RIDGING ARRIVES IN THE AFTERNOON
BUT NOT SURE IF THERE WILL BE MUCH SUN AS LOW LEVEL MOISTURE MAY
BE STUCK UNDER A SUBSIDENCE INVERSION. HIGHS SHOULD BE IN THE 60S
AND POSSIBLY 70 IF THERE IS MUCH SUNSHINE.

SKIES MAY BEGIN TO CLEAR THIS EVENING THOUGH IF THEY DO LOW CLOUDS
OR FOG MAY FORM DUE TO THE LOW LEVEL MOISTURE REMAINING. BEST
CHANCE OF FOG IS IN THE NORTH.

SATURDAY SHOULD BE PARTLY SUNNY AND WARMER AS A WARM FRONT MOVES
NORTH ACROSS THE REGION WELL AHEAD OF SYNOPTIC SCALE SYSTEM OVER
THE PLAINS STATES. HIGHS IN THE 70S AND DEWPOINTS IN THE 50S
PRODUCE CAPES OF 300 IN THE EAST TO 1000 IN CENTRAL WISCONSIN. BUT
THE DYNAMICS ARE NOT GREAT TO INITIATE CONVECTION.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 402 AM CDT FRI MAY 15 2015

CLOSED UPPER LOW ACROSS THE SOUTHWESTERN UNITED STATES WILL OPEN
UP AS IT EJECTS NORTHEAST INTO THE WESTERN GREAT LAKES BY EARLY
NEXT WEEK. 500MB PATTERN WILL BECOME ZONAL...ALTHOUGH HEIGHTS WILL
BE BELOW NORMAL FOR THIS TIME OF YEAR BY THE MIDDLE OF NEXT WEEK.

A WEAK DISTURBANCE WILL MOVE ACROSS THE WESTERN GREAT LAKES REGION
SATURDAY NIGHT...BRINGING A CHANCE OF SHOWERS AND STORMS. A FEW
OF THE STORMS MAY BE STRONG ACROSS PORTIONS OF CENTRAL AND NORTH-
CENTRAL WISCONSIN SATURDAY EVENING. MODIFIED SOUNDINGS INDICATED
CAPES AROUND 1000 J/KG...WET BULB HEIGHTS AROUND TEN THOUSAND
FEET AND WINDEX VALUES OF 35 TO 40 KNOTS.

ATTENTION THEN TURNS TO SUNDAY AS 0-6KM SHEAR INCREASES TO 40 TO
50 KNOTS. MODIFIED WAUSAU SOUNDING INDICATED 1000-1500 J/KG OF
CAPE AND WINDEX VALUES APPROACHING 50 KNOTS. WET BULB HEIGHTS WERE
A TAD BIT HIGHER...BUT STRONG SHEAR SHOULD OFFSET THIS RISE. SPC
DAY 3 HAS MUCH OF THE AREA IN A SLIGHT RISK OF SEVERE STORMS.
THE STORMS SHOULD EXIT THE REGION SUNDAY EVENING. THE LATEST MODELS
INDICATE DRY SLOT MOVING ACROSS MUCH OF THE AREA AFTER MIDNIGHT...
THUS LOWERED RAIN CHANCES SUBSTANTIALLY BETWEEN 1 AM AND 7 AM MONDAY.
LATER SHIFTS MAY BE ABLE TO REMOVE THE RAIN COMPLETELY.

HIGH TEMPERATURES ON MONDAY WILL BE DECEIVING. WITH SOME MORNING
SUNSHINE...TEMPERATURES SHOULD RISE INTO THE 50S NORTH TO THE
MID 60S ACROSS NORTHEAST WISCONSIN. THE COLDER AIR WILL FILTER INTO
THE REGION DURING THE DAY...THUS TEMPERATURES WILL MORE THAN LIKELY
FALL DURING THE AFTERNOON.

FROST POTENTIAL NORTH AND WEST OF THE FOX VALLEY MONDAY NIGHT
COMPLICATED BY CLOUD COVER AND WINDS. ALSO...HAVE A SMALL CHANCE
OF RAIN AND YES SNOW SHOWERS AFTER MIDNIGHT OVER THE VERY FAR
NORTH. FROST POTENTIAL LOOKS MUCH BETTER FOR TUESDAY NIGHT AND
WEDNESDAY NIGHT NORTH AND WEST OF THE FOX VALLEY DUE TO CLEAR
SKIES AND LIGHT WINDS AS HIGH PRESSURE DROPS INTO THE REGION.
THERE COULD BE A FEW HOURS OF FREEZING TEMPERATURES IN THE TYPICAL
COLD SPOTS ACROSS THE NORTH TUESDAY NIGHT AND WEDNESDAY NIGHT.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1248 PM CDT FRI MAY 15 2015

RELATIVELY LOW FORECAST CONFIDENCE FOR THIS TAF
PERIOD. MAINLY IFR CIGS SHOULD GRADUALLY GIVE WAY TO MOSTLY VFR
CONDITIONS WITH SOME MVFR CIGS TODAY. 12Z NAM AND GFS MOS PRODUCTS
INDICATED LOW CIGS AND DENSE FOG TONIGHT INTO EARLY SATURDAY. HAVE
GENERALLY USED A TEMPO GROUP IN THE TAFS TO HANDLE THIS WITH
HIGHER CIGS AND VSBYS IN THE PREVAILING FORECAST. CONDITIONS
SHOULD IMPROVE DURING THE MORNING. THERE COULD BE SOME SHOWERS OR
THUNDERSTORMS ACROSS PART OF CENTRAL WISCONSIN...BUT WOULD NOT
EXPECT ANYTHING TO GET AS FAR NORTH AS CWA OR AUW UNTIL LATER IN
THE DAY.
&&

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

$$

SHORT TERM.....RDM
LONG TERM......ECKBERG
AVIATION.......MG






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