Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 040218
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
918 PM CDT FRI JUL 3 2015

.UPDATE...
A DRY AND COOL AIR MASS REMAINS OVER THE REGION DUE TO A SURFACE
RIDGE OF HIGH PRESSURE STRETCHED ACROSS THE SOUTHERN GREAT LAKES.
THE 04.00Z RAP SOUNDINGS THROUGH SOUTHERN WISCONSIN SUGGEST THAT
CONDITIONS WILL STAY DRY ENOUGH THAT FOG SHOULD NOT DEVELOP
OVERNIGHT...OUTSIDE OF POSSIBLY IN THE WISCONSIN RIVER VALLEY.

A COLD FRONT WILL THEN HANG UP ACROSS CENTRAL WISCONSIN TOMORROW
AFTERNOON WITH SOME INSTABILITY DEVELOPING ALONG THIS BOUNDARY.
LITTLE TO NO WIND SHEAR IS PRESENT...SO ANYTHING THAT MAY DEVELOP
WILL BE VERY ISOLATED AND PULSEY. THE CANADIAN/ALASKAN WILDFIRES
HAVE ALSO CAUSED HAZY/SMOKEY CONDITIONS ACROSS MUCH OF THE
NORTHERN PLAINS TODAY ALONG AND NORTH OF THE BOUNDARY WHERE
SURFACE DEW POINTS INCREASE TO AROUND 60F OR HIGHER. SOME OF THAT
COULD GET INTO THE FORECAST AREA TOMORROW AFTERNOON...BUT
CONFIDENCE IS NOT HIGH ENOUGH THAT IT WILL TO WARRANT PUTTING IT
INTO THE FORECAST AT THIS POINT.

&&

.AVIATION/06Z TAFS/...
LIGHT WINDS WILL CONTINUE OVERNIGHT AS A RIDGE OF HIGH PRESSURE
SITS OVER THE REGION.  A COLD FRONT WILL STALL OUT ACROSS CENTRAL
WISCONSIN AND PIVOT BACK NORTHWARD TOMORROW AFTERNOON...SO ANY
POTENTIAL SHOWERS AND THUNDERSTORMS SHOULD STAY TO THE NORTH OF
THE LOCAL TAF SITES. HOWEVER...A MIX OF HAZE AND SMOKE FROM THE
CANADIAN/ALASKAN WILDFIRES HAS KEPT VISIBILITY DOWN INTO THE 2 TO
4SM RANGE ACROSS MUCH OF THE DAKOTAS AND MINNESOTA TODAY...WHICH
COULD PUSH EASTWARD TOMORROW AS THE FRONT SAGS SOUTHWARD.
CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO PUT ANY VISIBILITY
DROPS INTO THE FORECAST AT THIS TIME...BUT TRENDS WILL HAVE TO BE
MONITORED.


&&

.PREV DISCUSSION... /ISSUED 325 PM CDT FRI JUL 3 2015/

TONIGHT...FORECAST CONFIDENCE - MEDIUM.

WATER VAPOR/RAP SHOWS MID LEVEL SHEAR AXIS EXTENDING FROM CNTRL IL
INTO THE EASTERN LAKES SHIFTING AWAY FROM SRN WI. MEANWHILE VRY LGT
FLOW PERSISTS WITH BROAD SURFACE RIDGE AXIS SPANNING FROM THE CNTRL
PLAINS INTO LWR MI. MILKY SKIES TO PERSIST DUE TO THE SMOKE FROM
CANADIAN WILDFIRES. CU FIELD EXPECTED TO DISSIPATE THIS EVENING WITH
BETTER FORCING AND SHRA POTENTIAL TO OUR NORTH WITH NORTHERN STREAM
ENERGY AND FRONT TRAVERSING THE U.P. AND NRN WI. WHILE MID LEVEL
ENERGY PEELS AWAY TO THE EAST THE SURFACE BOUNDARY IS PROGGD TO SAG
INTO CNTRL WI LATER...BUT WITH LOSS OF HEATING AND UPPER SUPPORT
EXPECT ANY LINGERING SHRA IN NRN OR CNTRL WI TO NOT HOLD TOGETHER
INTO MKX CWA.

SATURDAY...FORECAST CONFIDENCE - MEDIUM

PRESSURE TROUGH OR FRONTAL BOUNDARY IN A WEAKENED STATE WILL BE
ACROSS PARTS OF SOUTHERN OR CENTRAL WI. A WEAK MID LEVEL SHORTWAVE
COMBINED WITH AN UPTICK IN CAPE MAY SET OFF A SHRA OR TSRA. MODELS
HAVE BEEN HINTING AT THIS AND SEE NO REASON TO CHANGE THE SMALL POPS
IN THE GRIDS. 925 TEMPS NUDGE A BIT MORE SO WARMER...THOUGH
DEPENDING ON SMOKE COVERAGE/THICKNESS...TEMPS MAY BE TEMPERED
SOMEWHAT.

SATURDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE - MEDIUM.

WILL CARRY SMALL POPS INTO EARLY SATURDAY EVENING DUE TO LINGERING
INSTABILITY ALONG WEAKENING CONVERGENCE ZONE ACROSS CENTRAL WI.
OTHERWISE A WARMER AND DRY PERIOD IS EXPECTED THE REMAINDER OF THE
HOLIDAY WEEKEND AS SUBSIDENCE ASSOCIATED WITH SHORT WAVE RIDGE
EXPANDS ACROSS THE WESTERN GTLAKES AHEAD OF APPROACHING TROF.  SOUTH
WINDS AND 925H TEMPS WARMING INTO THE 22-23C RANGE WILL ALLOW
DAYTIME TEMPERATURES TO WARM ABOVE SEASONAL LEVELS FOR JULY 5TH AWAY
FROM LAKE MI.  FEW SPOTS WL LIKELY REACH THE UPPER 80S.  THESE WARM
TEMPS ARE BASED ON THE CANADIAN SMOKE FIELD GETTING NUDGED NORTHWARD
BY INCREASING WINDS FROM THE SOUTH.

AFTER A MILD AND DRY NIGHT SUNDAY NIGHT...ANOTHER WARM DAY IS
EXPECTED IN SOUTHEAST WISCONSIN.  BREEZY SOUTH WINDS AND FILTERED
MORNING SUNSHINE SHOULD HELP TEMPS WARM AGAIN INTO THE MID TO UPPER
80S...BUT REMAINING SLIGHTLY COOLER RIGHT ALONG LAKE MI.  SHORT TERM
GUIDANCE IN GOOD AGREEMENT ON VIGOROUS SHORT WAVE TROUGH MOVING THRU
SRN WI FROM MON AFTN THRU MON NGT.  INCREASING COLUMN MOISTURE AND
LAYER Q-VECTOR CONVERGENCE SHOULD RESULT IN SCT TO NUMEROUS SHOWERS
AND STORMS DEVELOPING MAINLY IN THE AFTN.  LLJ FOCUS HOWEVER WILL BE
FARTHER NORTH ACROSS NRN WI.

SHORT TERM GUIDANCE DIFFERS ON AMOUNT OF BULK SHEAR AND INSTABILITY.
SFC DEWPTS SHOULD BE IN THE MID TO UPPER 60S BY THEN BUT ELEVATED
INSTABILITY MORE IN QUESTION ALONG WITH SHEAR.  LOCAL PARAMETERS
INDICATING SMALL POTENTIAL FOR SEVERE PROVIDED CLOUDS DON/T INCREASE
TO RAPIDLY ON MONDAY.  WOULD NOT BE SURPRISED IF CWA INCLUDED IN A
MARGINAL AREA FOR DAY 3 BY SPC TONIGHT.

MONDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE - MEDIUM
TRENDING TOWARD LOW.

WILL CONTINUE LIKELY WORDING FOR SHOWERS AND STORMS MONDAY NIGHT AS
SFC CDFNT AND MID-LEVEL SHORT WAVE TROF MOVE THROUGH WI DURING THE
EVENING.  ABUNDANT COLUMN MOISTURE WILL BE AVAILABLE AS PWAT VALUES
EXPECTED TO EXCEED 2 INCHES DURING THE EVE.  MEDIUM RANGE GUIDANCE
IN GOOD AGREEMENT ON CARRYING SFC FNT THRU SE WI AROUND 06Z/TUE WITH
DRIER AIR AND SUBSIDENCE RETURNING IN ITS WAKE.  HENCE PREFER LOWER
POPS FOR THE LATE NIGHT PERIOD.

BRIEFLY ZONAL FLOW CARRIES WEAK SHORT WAVE RIDGE ACROSS THE WESTERN
GTLAKES TUE INTO WED.  MID-LEVEL FLOW BEGINS TO BACK AHEAD OF
APPROACHING SHORT WAVE FOR THE THU/FRI TIMEFRAME.  GUIDANCE DIVERGES
ON THE STRENGTH OF THIS LATE WEEK SHORT WAVE.  00Z ECMWF CARRIES
WEAK WAVE THRU WRN GTLAKES WED NGT/THU MRNG WITH ZONAL FLOW QUICKLY
RETURNING.  00Z GFS SHOWS MUCH MORE AMPLIFIED LONG WAVE TROF AND
GREATER THREAT FOR WIDESPREAD QPF ACROSS SRN WI ON THU/THU EVE.
DESPITE LACK OF MODEL RUN CONSISTENCY FROM DETERMINISTIC
ECMWF...ECMWF ENSEMBLE TRENDING TOWARD WEAKER AND MORE PROGRESSIVE
SOLUTION.  WPC AND NAF ENSEMBLE ALSO LEANING TOWARD THIS SOLUTION.
FOR NOW...WL HAVE SMALL CHANCES FROM THE WED NGT THRU THU NIGHT
PERIOD BUT MAY BE ABLE TO PARE THESE BACK IN FUTURE FORECASTS SHOULD
THIS TREND CONTINUE.  TEMPERATURES ARE EXPECTED TO BE NEAR OR
SLIGHTLY BELOW SEASONAL NORMAL INTO THE SECOND WEEK OF JULY FOR MOST
OF THIS PERIOD.

AVIATION/00Z TAFS/...

SHEAR AXIS FROM IL INTO ERN LAKES MOVG AWAY.   EXPECTING ANY
CONVECTION FROM NRN WI WITH NRN ENERGY/FRONT TO DISSIPATE BEFORE
REACHING TAF SITES LATER THIS EVENING. OVERALL VFR CONDITIONS
EXPECTED TO PERSIST INTO SATURDAY. VERY WEAK TROUGH AND WEAK UPPER
WAVE WILL NECESSITATE VRY SML POPS FOR SATURDAY. NAM AND GFS SHOW
VARYING AMOUNTS OF CAPE THOUGH MOISTURE RETURN MAY NOT BE QUICK
ENOUGH GIVEN WEAK FLOW AROUND UPPER MIDWEST.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

UPDATE...HALBACH
TONIGHT/SATURDAY AND AVIATION/MARINE...COLLAR
SATURDAY NIGHT THROUGH FRIDAY...MBK



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