Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 180134
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
834 PM CDT SUN MAY 17 2015

.UPDATE...
LOOKS LIKE ANY CHANCE FOR SHOWERS HAS ENDED. THE DRY AIR HAS
OVERSPREAD THE AREA AHEAD OF AN APPROACHING COLD FRONT. THE FRONT
WON/T HAVE ANYTHING TO WORK WITH AND WILL COME THROUGH DRY LATE
TONIGHT THROUGH ABOUT MID MORNING ON MONDAY. SO...LOOK FOR A
FAIRLY QUIET NIGHT WITH WINDS REMAINING SOMEWHAT ELEVATED AND
TEMPS FALLING BACK INTO THE MID 50S TO LOWER 60S.

&&

.AVIATION/06Z TAFS/...

VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. THE ONLY
OPERATIONAL CONCERN WILL BE LOW LEVEL WIND SHEAR THROUGH ABOUT
10-12Z MONDAY. WINDS AT 2000FT WILL BE AROUND 35-40KTS WHILE AT
THE SURFACE THEY MAY DIMINISH TO AROUND 10KTS. A COLD FRONT WILL
SWEEP ACROSS THE AREA...DRY...FROM ABOUT 10-14Z MONDAY WITH WINDS
BECOMING WESTERLY BEHIND THE FRONT. WINDS WILL BE GUSTY TO NEAR 25
KNOTS MONDAY AFTERNOON...DIMINISHING BY MONDAY EVENING.

&&

.PREV DISCUSSION... /ISSUED 330 PM CDT SUN MAY 17 2015/

SHORT TERM...

TONIGHT...FORECAST CONFIDENCE MEDIUM.

THE HRRR MODEL HAS BEEN CONSISTENT TODAY AND SO FAR CORRECT. OTHER
MESO MODELS ARE SIMILAR. A LINE OF SHOWERS AND THUNDERSTORMS WAS
ORIENTED ROUGHLY NORTH TO SOUTH ACROSS THE CENTRAL MKX FORECAST AREA
AT 2 PM THIS AFTERNOON. THIS LINE IS SLOWLY TRACKING EAST WITH MID
LEVEL VORTICITY ADVECTION. THESE ARE WORKING OFF THE HIGHER CAPE
AXIS THAT DEVELOPED OVER INLAND WI AREAS AND ALSO WEAK SURFACE
CONVERGENCE. THE CONVECTION IS LOW-TOPPED SINCE MID LEVEL LAPSE
RATES ARE WEAK. THEREFORE... MANY OF THE ECHO TOPS ARE BENEATH THE
FREEZING LEVEL OF 12.5 KFT AND ARE NOT EVEN PRODUCING THUNDER.
SEVERAL CELLS HAVE TOPS AROUND 20 KFT AND WE ARE SEEING CLOUD TO
GROUND LIGHTNING STRIKES WITH THEM.

PER THE HRRR AND OTHER MESO MODELS... THESE SHOWERS WILL CONTINUE
EAST THROUGH 6 PM... ALL THE WAY THROUGH MILWAUKEE. EXPECT HEAVY
DOWNPOURS. BRIEF LOCALIZED FLOODING IS POSSIBLE IN URBAN AREAS.

THERE IS A BREAK BEHIND THIS LINE OF SHOWERS AND STORMS LATE THIS
AFTERNOON. LOOK FOR GUSTY SOUTH-SOUTHWEST WINDS AS THE LOW LEVELS
MIX OUT AND DEWPOINTS DROP TO AROUND 60. CAPE/INSTABILITY WILL LOWER
IN THIS AREA. 0-6KM BULK SHEAR WILL REMAIN HIGH... AROUND 40 KT.

THERE IS ONE MORE CHANCE FOR STORMS ACROSS SOUTHERN WI THIS
EVENING... BUT THE CHANCE IS BECOMING VERY LOW. THE HRRR... NAMNEST
AND OTHER MESO MODELS ARE SHOWING QUITE A DRY SCENARIO FOR OUR AREA.
THE FEATURE WE HAVE BEEN FOCUSING OUR ATTENTION ON FOR SEVERE
POTENTIAL IS AN UPPER LEVEL WAVE AND A SURFACE PRE-FRONTAL TROUGH
ASSOCIATED WITH AN OCCLUDING LOW PRESSURE SYSTEM OVER THE EASTERN
DAKOTAS AND WEST CENTRAL MN. THE UPPER WAVE NOW LOOKS LIKE IT WILL
COME THROUGH SOUTHERN WI A LITTLE AHEAD OF THE PRE-FRONTAL TROUGH...
SO DEVELOPMENT OF STORMS WILL BE HARDER TO ACHIEVE. IF ANY STORMS
DEVELOP... THE CAPE WILL BE MARGINAL AND SHEAR WILL BE HIGH. THUS...
THERE IS STILL A SMALL RISK FOR SEVERE. SPC STILL HAS OUR AREA IN A
SLIGHT RISK FOR SEVERE STORMS.

SKIES SHOULD CLEAR LATE THIS EVENING WITH THE DRY AIR WRAPPING INTO
SOUTHERN WI AS THE SURFACE LOW TRACKS INTO NORTHEAST MN. WINDS WILL
SHIFT TO THE SW AND WEST TOWARD MORNING.

MONDAY...FORECAST CONFIDENCE HIGH.

THE SURFACE/925MB COLD FRONT WILL TRACK THROUGH SOUTHERN WI DURING
THE DAY MONDAY. IT WILL BE SLOW TO REACH SOUTHEAST WI... THUS MAX
TEMPS WILL BE IN THE MID 70S THERE. THE DELLS AREA WILL BE COOLEST
WITH HIGHS AROUND 60. EXPECT BRISK AND GUSTY WEST WINDS DUE TO A
STRONG PRESSURE GRADIENT OVER THE REGION.

MONDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.

THE UPPER LOW OVER NRN MN WILL BECOME AN OPEN WAVE AND MOVE ACROSS
LAKE SUPERIOR AND INTO ONTARIO CANADA MON NT. A WEAKER SHORTWAVE
TROUGH WILL ALSO MOVE ACROSS CENTRAL WI DURING THAT TIME. THE
SHORTWAVE WILL LIKELY AID IN BROKEN STRATUS SHIFTING SOUTH INTO S
WI ALONG WITH THE NWLY SFC FLOW AND COLD ADVECTION. NLY SFC FLOW
WILL CONTINUE INTO TUE BUT WITH WEAKENING COLD ADVECTION. DAYTIME
HEATING AND DRIER AIR SHOULD BE ENOUGH TO SCATTER OUT THE STRATUS
DECK. HOWEVER HIGH TEMPS WILL REMAIN WELL BELOW NORMAL WITH 925 MB
TEMPS ONLY WARMING TO 5-7C.

AN UPPER LOW OVER THE WRN USA WILL THEN OPEN UP AS A SHORTWAVE
TROUGH AND MOVE TOWARD WI FOR WED. DESPITE MID LEVEL FRONTOGENESIS
OVER THE REGION...KEPT THE FCST DRY AS MUCH OF THE LOW TO MID
LEVEL WARM...MOIST ADVECTION STAYS TO THE SOUTH. THUS EXPECT MO
CLOUDY SKIES FROM MIDDLE TO HIGH CLOUDS. THE CLOUDS WILL KEEP THE
HIGH TEMPS MAINLY IN THE 50S FOR THE 2ND DAY IN A ROW.

LONG TERM...

THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM.

THE SRN PERIPHERY OF AN UPPER TROUGH WILL MOVE ACROSS THE NORTHERN
AND EASTERN GREAT LAKES THU-FRI. THIS IS EXPECTED TO BRING A WEAK
AND DRY BACKDOOR COLD FRONT ACROSS SRN WI ON FRI. HIGH PRESSURE
WILL THEN FOLLOW FROM THE NORTHERN GREAT LAKES TO THE EASTERN
GREAT LAKES FOR FRI-SAT. FOR SAT NT AND SUN AN UPPER TROUGH WILL
EJECT NEWD TOWARD WI FROM THE 4 CORNERS REGION ALONG WITH ITS SFC
TROUGH. A GOOD SURGE OF WARM...MOIST ADVECTION AND SHOWERS/TSTORMS
ARE EXPECTED. TEMPS WILL RETURN TO NEAR NORMAL FOR THE THU-SUN
PERIOD.

AVIATION/00Z TAFS/...

AN AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL WI SHOULD
EXPAND AS IT TRACKS INTO SOUTHEAST WI THROUGH 6 PM. THIS WILL BE
ABOUT A 2 HOUR PERIOD OF MODERATE TO HEAVY RAIN AND OCCASIONAL
THUNDER.

LOOK FOR A QUIET PERIOD OF WEATHER LATE THIS AFTERNOON. THERE IS ONE
MORE SMALL CHANCE FOR THUNDERSTORMS EARLY THIS EVENING... BUT THAT
CHANCE IS NOW LOOKING VERY LOW.

THE RISK FOR SEVERE WEATHER HAS DECREASED... BUT ISOLATED SEVERE
STORMS ARE STILL POSSIBLE.

LOOK FOR CLEARING SKIES OVERNIGHT. GUSTY WEST WINDS AND SCATTERED TO
BROKEN VFR CUMULUS CLOUDS EXPECTED MONDAY.

MARINE...

DENSE FOG ADVISORY WAS EXTENDED UNTIL 00Z/ 7PM THIS EVENING DUE TO
PERSISTENT SOUTHEAST WINDS AND WARM AND HUMID AIR OVER THE LAKE.
INCREASING SOUTH TO SOUTHWEST WINDS SHOULD PUSH ANY LINGERING FOG
OUT OF THE NEARSHORE WATERS THIS EVENING.

&&

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

$$

UPDATE...DAVIS
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...GEHRING


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