Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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000
FXUS63 KMKX 010226
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
926 PM CDT MON AUG 31 2015

.UPDATE...TEMPS DROPPED RAPIDLY EARLY THIS EVENING SO LOWERED
MINIMUM SEVERAL DEGREES MOST AREAS. AREAS OF FOG LIKELY TO
DEVELOP...BUT BOUNDARY LAYER MIXING SHOULD KEEP WIDESPREAD DENSE
FOG AT BAY. LIKELY TO BE SOME PATCHY DENSE FOG HOWEVER...ESPECIALLY
IN THE EAST CLOSER TO RIDGELINE AND MOIST MARINE LAYER.

&&

.AVIATION/06Z TAFS/...FOG LIKELY TO AFFECT TAF SITES OVERNIGHT.
WIDESPREAD FOG OVER THE NEARSHORE WATERS WILL LIKELY AFFECT
LAKESHORE FOR A TIME...HOWEVER LAKESHORE WINDS EXPECTED TO TURN TO
THE SOUTH TO SOUTHWEST...KEEPING MOST OF THE LAKE FOG AT/OFF
SHORE. DEWPTS ABOUT 3 DEGREES WARMER THAN YESTERDAY AND HIGH
AFTERNOON CROSS OVER TEMPS AND CLEAR SKIES LIKELY TO ALLOW FOG TO
DROP VSBYS TO MVFR. WL CONTINUE IFR VSBYS AT KENW DUE TO HIGH
CROSS OVER TEMP AND CLOSER PROXIMITY TO RIDGELINE. BETTER LOW
LEVEL MIXING LIKELY TO KEEP DENSE FOG AT BAY ELSEWHERE. RECENT
ASCENT KMKE TAMDAR SOUNDING SHOWS STRONG MIXING ABOUT 1K FEET OFF
SURFACE.

&&

.MARINE...LATEST 11-3.9 MICRON IMAGERY SHOWING DENSE FOG RAPIDLY
EXPANDED AND NOW COVERS MOST OF THE NEARSHORE WATERS...WHICH IS
CONFIRMED BY LAKESHORE WEBCAMS. MODIS IMAGERY ESTIMATED NEARSHORE
LAKE SURFACE TEMPS IN THE LOW 50S EARLY TODAY...BUT THEN WARMED
INTO THE MID TO UPPER 50S DURING THE AFTN. RECENT UPWELLING
INCIDENT HAS CAUSED THE COOL WATER TO SURFACE AS OFF SHORE LAKE
SFC TEMPS MOSTLY IN THE 60S.

WITH THE WARM...MOIST AIR STICKING AROUND FOR MUCH OF THE COMING
WEEK...BOUTS OF DENSE FOG ARE LIKELY TO CONTINUE UNTIL THE SURFACE
WATER TEMP WARMS AT LEAST 5 TO 10 DEGREES.

&&

.PREV DISCUSSION... /ISSUED 252 PM CDT MON AUG 31 2015/

SHORT TERM...

TONIGHT - CONFIDENCE...MEDIUM
STRATUS DECK MORPHED INTO CU FIELD. EXPECT THIS TO DIURNALLY DISSIPATE.
FOG POTENTIAL STILL THERE WITH OVERALL LIGHT WIND REGIME AND HIGH DEW
POINTS. HOWEVER THERE IS A BIT MORE STIRRING OFF THE DECK SO NOT
EXPECTING WIDESPREAD DENSE FOG TO BE A CONCERN. MOS TEMPS APPEAR
REASONABLE.

TUESDAY - CONFIDENCE...HIGH
AFTER ANY MORNING FOG ERODES 925/850 THERMAL RIDGE LEANS INTO THE CWA
WITH 925 TEMPS REACHING THE MID 20S CELSIUS. SO EXPECT HIGHS TO REACH
WELL INTO THE 80S WITH A FEW SPOTS REACHING 90. EVOLVING ONSHORE
COMPONENT WILL DROP TEMPS BACK A BIT LAKESIDE AS THE AFTERNOON WEARS ON.

TUESDAY NIGHT THROUGH THU NT..

A LARGE SCALE UPPER TROUGH WILL PREVAIL OVER WRN CANADA AND THE
PACIFIC NW WITH RIDGING OVER MUCH OF THE CENTRAL AND ERN USA
DURING THIS PERIOD. HOWEVER...WEAK SHORTWAVE TROUGHS WILL EXIST
WITHIN THE RIDGING AREA. ONE SUCH SHORTWAVE TROUGH IS EXPECTED TO
TRACK ACROSS CENTRAL OR SRN WI FOR LATE WED INTO THU. MLCAPES ARE
EXPECTED TO CLIMB TO 1500-2000 J/KG FOR WED AFT WITH LITTLE
CAPPING...BUT ALSO LITTLE TO NO SFC CONVERGENCE. SOME MODELS DO
HAVE QPF AT TIMES ALTHOUGH MODEL AND MOS POP GUIDANCE IS VERY LOW
DURING THIS PERIOD. THUS WENT WITH SLIGHT CHANCE POPS FOR THE
AFTERNOON OVER SOUTH CENTRAL WI AND OVER THE ENTIRE CWA FOR WED NT
AND THU.

HIGH TEMPS THE LAST COUPLE DAYS HAVE BEEN COOLER THAN
FORECAST DUE TO STRATUS AND FOG AND CANNOT COMPLETELY RULE THIS
OUT FOR THIS PERIOD...ALTHOUGH STILL BELIEVE TEMPS WILL BE ABLE TO
WARM INTO THE MID-UPPER 80S. HEAT INDEX VALUES WILL REACH THE
LOWER 90S.

LONG TERM...FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM.

A VERY WARM...HUMID...AND UNSTABLE AIRMASS WILL CONTINUE FOR THE
WEEKEND. THUS SMALL CHANCES OF TSTORMS ARE FORECAST AT TIMES BUT
WILL INCREASE ON LABOR DAY AS A COLD FRONT APPROACHES. THE MODELS
DIFFER ON THE STRENGTH OF THE COLD FRONT AND ASSOCIATED PCPN AT
THIS TIME.

AVIATION/00Z TAFS/...MVFR CU FIELD EXPECTED TO DISSIPATE WITH LOSS
OF DIURNAL HEATING. AIRMASS REMAINS MOIST AND GUID STILL SUGGESTING
FOG DEVELOPS AS THE NIGHT WEARS ON. LEANED A LITTLE CLOSER TO THE
METMOS ON VSBY TRENDS. 850/925 THERMAL RIDGE STARTS TO LEAN INTO THE
AREA TUESDAY WITH INCREASING SW FLOW. NAM SOUNDINGS NOT SHOWING MUCH
CU POTENTIAL.


MARINE...WEAK FLOW CONTINUES TONIGHT INTO TUESDAY WITH HIGH DEW
POINT AIRMASS OVER COOL WATERS OF THE LAKE. SOME UPTICK IN SOUTH
THEN SOUTHEAST WINDS ON TUESDAY BUT TRAJ FAVORS KEEPING FOG...SOME
DENSE...IN PLACE THROUGH AT LEAST TUESDAY MORNING. WITH POTENTIAL
LINGERING LONGER IN NORTHERN ZONES INTO TUE NGT. WITH GRADIENT
LOOKING OVERALL WEAK FOR THE BALANCE OF THE WEAK MAY BE SEEING MORE
OF THE DENSE FOG ADVISORY HEADLINES AS THE WEEK MOVES ALONG.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...DENSE FOG ADVISORY UNTIL 10 AM CDT TUESDAY FOR LMZ644>646.

     DENSE FOG ADVISORY UNTIL 7 AM CDT WEDNESDAY FOR LMZ643.

&&

$$

UPDATE...MBK


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