National Weather Service Text Product Display

Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 190440
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1140 PM CDT SAT MAY 18 2013

.UPDATE...STILL EXPECTING STRONG TO SEVERE THUNDERSTORMS SUNDAY
EVENING/NIGHT AS THE ERN PERIPHERY OF THE DIFFLUENT UPPER LOW OVER
THE CENTRAL PLAINS AND THE NOSE OF A 40 KT LOW LEVEL JET STREAM
SHIFTS EWD INTO SRN WI/NRN IL. ONGOING CONVECTION OR CONVECTIVE
INITIATION WILL LIKELY BE OCCURRING OVER IA AND SRN MN SUN
AFTERNOON. CORFIDI VECTORS...LOCATION OF LIFT...AND HIGH CAPE TO THE
SOUTH SUGGESTS MCS COULD TURN DUE EAST OR ESE VERSUS FOLLOWING THE
SLY 850-300 MB FLOW. THIS DEVIANT AND SLOWER MOTION COULD BE
FAVORABLE FOR FLASH FLOODING WITH PWS UP TO 1.5 INCHES.

SINCE SRN WI IS ON THE ERN PERIPHERY OF THE MID LEVEL FLOW...DEEP
LAYER SHEAR IS WEAK BUT THE SWLY FLOW ALOFT IS FLOWING OVER SSELY
FLOW AT THE SFC WITH 0-3 KM SRH INCREASING TO AROUND 200 M2/S2 AND
MLCAPES AROUND 2000 J/KG. 0-1 SRH IS AROUND 100 M2/S2 WITH 0-1 KM
SHEAR OF 15-20 KTS. THEREFORE HP SUPERCELLS WITH ATTENDANT
LARGE HAIL...DAMAGING WIND...FLASH FLOODING...AND A TORNADO
THREAT IS POSSIBLE OVER SOUTH CENTRAL WI UNLESS A SOLID LINE OF
CONVECTION ORGANIZES BEFORE MOVING INTO THE CWA THEREBY LIMITING
SUPERCELL DEVELOPMENT.

ERN WI WILL HAVE SUBSTANTIALLY LESSER MLCAPE DUE TO THE
PERSISTENT ONSHORE FLOW AND CONVECTION WILL LIKELY BE MORE
ELEVATED THERE. ADDITIONAL ROUNDS OF CONVECTION VIA THE LOW LEVEL
JET AND UPPER DIFFLUENCE IS EXPECTED MON-TUE WITH MUCH STRONGER
DEEP LAYER SHEAR IN PLACE TO SUPPORT ADDITIONAL SVR WX.


&&

.AVIATION/06Z TAFS/...PATCHY FOG/STRATUS MAY DEVELOP EARLY SUN AM
AS WINDS WEAKEN UNDER MO CLEAR SKIES. OTHERWISE SCT-BKN050 CUMULUS
WILL DEVELOP OVER SOUTH CENTRAL SUN AFTERNOON WITH LESSER CLOUDS
OVER THE ERN WI DUE TO THE COOLING EFFECTS OF LAKE MI. STRONG TO
SEVERE TSTORMS ARE THEN EXPECTED SUN EVENING AS A WARM FRONT
APPROACHES SRN WI. REDUCED CIGS AND VSBYS IN TSTORMS.



&&

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

$$

UPDATE...GEHRING

National Weather Service Regional Office