Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 310820
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
320 AM CDT SUN AUG 31 2014

.TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.

FIRST ISSUE IS FOG/LOW STRATUS TRENDS THROUGH THE MID MORNING HOURS.
VERY LIGHT/CALM WINDS WITH AT LEAST PARTIAL CLEARING HAS ALLOWED FOR
FOG TO FORM AT SEVERAL SITES. ALSO SEEING LOW STRATUS FORMING IN
SPOTS...MORE SO IN THE NORTHERN COUNTIES. EXPECT THE FOG AND LOW
STRATUS TO LINGER INTO THE MIDDLE MORNING HOURS...BEFORE QUICKLY
DISSIPATING. SHOULD SEE SOME DENSE FOG IN THE WISCONSIN RIVER VALLEY
AREA...AND IN USUAL LOW SPOTS. FOG SHOULD NOT BE DENSE IN OTHER
AREAS...OR REMAIN SHORT LIVED...GIVEN PRESENCE OF LOW STRATUS.

SOUTH TO SOUTHEAST WINDS SHOULD ALLOW FOR MOSTLY SUNNY SKIES THIS
MORNING...THEN BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SOME DIURNAL CUMULUS CLOUD DEVELOPMENT. 925 MB TEMPERATURES SUGGEST
LOWER TO MID 80S INLAND FOR HIGHS...WITH COOLER MIDDLE TO UPPER 70S
NEAR THE LAKE WITH ONSHORE WINDS.

MODELS IN PRETTY GOOD AGREEMENT WITH BRINGING COLD FRONT EASTWARD
TOWARD THE AREA TONIGHT. WESTERN PORTIONS OF THE AREA SHOULD BE
WITHIN 850 MB SOUTHWESTERLY LOW LEVEL JET AXIS AND WARM AIR
ADVECTION. THIS AREA ALSO SEES A 500 MB VORTICITY MAXIMUM SHIFT
NORTHEAST TOWARD THE AREA LATER TONIGHT...AS WELL AS SOME UPPER
DIVERGENCE FROM RIGHT REAR QUADRANT OF 250 MB JET STREAK.

AREA FORECAST SOUNDINGS AGREE ON AIR COLUMN BECOMING MORE MOIST IN
THE LOW LEVELS...WITH BUILDING ELEVATED CAPE...DEEP LAYER SHEAR AND
PRECIPITABLE WATER VALUES. THUS...WILL CONTINUE WITH TRENDING UP
POPS LATER TONIGHT IN THE WESTERN COUNTIES. NAM/GFS CWASP VALUES
INCREASE TO LOWER 70S BY 12 MONDAY IN THE FAR WEST/NORTHWEST.
SO...MAY BE A STRONG STORM OR TWO IN THIS AREA LATER TONIGHT.

.MONDAY...FORECAST CONFIDENCE...MEDIUM

SHOWERS AND STORMS ARE LIKELY IN THE WEST BY DAYBREAK MONDAY
MORNING AND THEN ACROSS THE FORECAST AREA DURING THE DAY AS A COLD
FRONT MOVES THROUGH THE REGION. STILL THINK SOME STRONG TO SEVERE
STORMS ARE POSSIBLE...BUT THIS WILL BE DEPENDENT ON THE TIMING OF
THE FRONT. OVERALL...IT LOOKS LIKE A DECENT AMOUNT OF INSTABILITY
TO GO ALONG WITH AROUND 40-50 KNOTS OF 0-6 KM BULK SHEAR. SPC DAY
2 CONVECTIVE OUTLOOK NOW HAS THE ENTIRE FORECAST AREA IN A SLIGHT
RISK FOR SEVERE STORMS.

MAIN CONCERN WITH THIS SETUP IS THAT RIGHT NOW IT LOOKS LIKE
OVERNIGHT CONVECTION WILL LIMP IN DURING THE MORNING HOURS...WITH
THE DEEPEST MOISTURE AND BEST INSTABILITY SETTING UP SOUTH OF THE
WI/IL BORDER FOR THE AFTERNOON AND EVENING. MOST OF THE MODELS
HAVE THE WIDESPREAD STORMS DEVELOPING SOUTH OF THE AREA LATER IN
THE DAY...WITH SOME DEVELOPMENT FARTHER NORTH INTO THE FORECAST
AREA ALONG THE COLD FRONT. PRECIPITABLE WATER VALUES ARE
PROJECTED TO DROP TO AROUND 1.30 INCHES ACROSS SOUTHERN WISCONSIN BY
AFTERNOON...SO CERTAINLY LESS MOISTURE TO WORK WITH. STILL SOME
TIME FOR DETAILS TO CHANGE THOUGH...AS CONVECTIVE SITUATIONS ARE
NEVER SET IN STONE.

.TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...HIGH

IT LOOKS MAINLY DRY TUESDAY AND WEDNESDAY AS SURFACE HIGH PRESSURE
SLIDES THROUGH THE AREA. A COUPLE MODELS ARE SHOWING A WEAK WAVE
OR TWO BRINGING SOME SPLOTCHY QPF HERE AND THERE...BUT NOT SEEING
A CONSISTENT SIGNAL AT THIS POINT SO KEPT THE FORECAST DRY. WARM
TEMPS WILL CONTINUE WITH HIGHS NEAR TO A FEW DEGREES ABOVE NORMAL.

.THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE...MEDIUM

A RETURN OF MOISTURE UNDER SOUTHERLY LOW LEVEL FLOW IS EXPECTED TO
BRING A CHANCE FOR SHOWERS AND STORMS BACK TO THE AREA THURSDAY
AND FRIDAY. THERE IS LOWER CONFIDENCE IN POPS ON THURSDAY...AS
ECMWF AND CANADIAN HAVE MORE OF A CAPPED LOOK FOR SOUTHERN
WISCONSIN...KEEPING THE PRECIP MAINLY NORTH OF THE AREA. BETTER
CHANCE FOR SHOWERS/STORMS FRIDAY THEN AS THE COLD FRONT MOVES
THROUGH. DEPENDING ON THE TIMING OF THE FRONT...LOOKS MAINLY DRY
SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.

IT COULD GET QUITE WARM THURSDAY IF IT STAYS DRY...AS MODEL 925
MB TEMPS GET UP TO AROUND 25C. THIS WOULD RESULT IN HIGHS NEAR
90...SO TRENDED THE FORECAST WARMER. THROW IN DEWPOINTS IN THE
LOW 70S AND IT WOULD BE AN UNCOMFORTABLE EARLY SEPTEMBER DAY.
IT SHOULD TREND COOLER FRIDAY AND SATURDAY AS A COOLER AIRMASS
MOVES IN BEHIND THE COLD FRONT.

&&

.AVIATION/12Z TAFS/...

EXPECT FOG AND LOW STRATUS TO GO UP AND DOWN BETWEEN VFR AND LIFR
CATEGORY INTO THE MIDDLE MORNING HOURS...BEFORE DISSIPATING. VERY
LIGHT/CALM WINDS ARE EXPECTED DURING THIS PERIOD. MAY NOT SEE LOW
STRATUS AT KENOSHA AND MILWAUKEE GIVEN CURRENT TRENDS. DENSE FOG IN
LOW LYING AREAS IS POSSIBLE...AND SHOULD BE SHORT LIVED.

VFR CONDITIONS ARE THEN EXPECTED FOR THE REST OF TODAY AND THROUGH
MOST OF TONIGHT. SOUTH WINDS WILL INCREASE IN SPEED SOMEWHAT DURING
THE DAY AT MADISON...WITH SOUTHEAST WINDS AT THE EASTERN SITES. SOME
DIURNAL CUMULUS IS POSSIBLE THIS AFTERNOON.

APPROACHING COLD FRONT FROM THE WEST MAY BRING SHOWERS AND
THUNDERSTORMS THAT WILL AFFECT MADISON BEFORE 12Z MONDAY. FOR
NOW...HELD OUT OF MADISON TAF FOR NOW DUE TO SOME UNCERTAINTY IN
TIMING AND PLACEMENT OF PRECIPITATION.

&&

.MARINE...

TIGHT PRESSURE GRADIENT ACROSS THE NEARSHORE WATERS MONDAY SHOULD
ALLOW FOR GUSTY SOUTH WINDS...BECOMING SOUTHWEST BY 00Z TUESDAY.
THIS MAY BRING FREQUENT 22 TO 25 KNOT GUSTS TO THE NEARSHORE WATERS
DURING THIS TIME. WAVES SHOULD BUILD TO 2 TO 4 FEET...MAINLY TOWARD
THE OPEN WATERS. LATER SHIFTS WILL NEED TO WATCH THE GUSTS FOR A
SMALL CRAFT ADVISORY.

&&

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

$$

TODAY/TONIGHT AND AVIATION/MARINE...WOOD
MONDAY THROUGH SATURDAY...DDV



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