000
FXUS63 KMKX 172034
AFDMKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
334 PM CDT FRI MAY 17 2013

.VERY SHORT TERM...TONIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM
TO HIGH.

ELEVATED SHOWERS CURRENTLY NORTH AND EAST OF THE DELLS THROUGH
JUNEAU AND PORT WASHINGTON...ASSOCIATED WITH 850MB
FRONTOGENESIS/WARM AIR ADVECTION...WILL VERY GRADUALLY LIFT NORTH
THIS EVENING. MODELS TEND TO MOVE THIS TYPE OF BOUNDARY NORTHWARD
TOO QUICKLY BECAUSE THEY ARE UNDER-DOING THE STRENGTH OF THAT HIGH
PRESSURE AREA OVER SOUTHERN ONTARIO AND LAKE SUPERIOR. SO KEPT HIGH
POPS OVER FOND DU LAC AND SHEBOYGAN AREAS THROUGH THE REST OF THE
EVENING. PRECIP SHOULD SHIFT NORTH OF THERE BY AROUND MIDNIGHT AS
THE BOUNDARY CONTINUES NORTH.

THE SURFACE FRONT INDICATED BY A WIND SHIFT/TEMP GRADIENT OVER
EASTERN IOWA AND NORTHERN IL WILL LIFT NORTHWARD INTO SOUTHWEST AND
SOUTH CENTRAL WI BY MIDDAY SATURDAY. CURRENTLY SHOWERS AND
THUNDERSTORMS ARE FIRING UP ALONG IT THIS AFTERNOON IN NORTHERN IL.
THIS BOUNDARY WILL BECOME THE FOCUS FOR DIURNALLY-DRIVEN SCATTERED
SHOWERS AND ISOLATED THUNDER FROM LATE SAT MORNING THROUGH THE LATE
AFTERNOON IN SOUTH CENTRAL WI INLAND FROM THE LAKE.

HIGHS SHOULD GET INTO THE UPPER 70S TO AROUND 80 INLAND FROM THE
LAKE GIVEN THE 925MB TEMPS INCREASING TO 19-20C. SOUTHEAST WINDS OFF
THE LAKE WILL CONTINUE TO KEEP THE LAKESHORE AREAS COOLER. EXPECTING
FILTERED SUNSHINE DUE TO HIGH CLOUDS HANGING OUT OVER THE REGION.

.SHORT TERM...SATURDAY NIGHT THROUGH MONDAY.

SATURDAY NIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.

MODEL SOUNDINGS ANY CAPE FROM EARLIER IN THE DAY OVER THE AREA
DIMINISHES AROUND 00Z...WITH SOUTHEASTERLY FLOW PUSHING BACK
LOW-LEVEL MOISTURE CONVERGENCE TO THE WEST...SO WILL NOT HAVE ANY
POPS SATURDAY NIGHT. WITH WINDS TURNING A BIT MORE SOUTHERLY IN THE
WEST...SHOULD HOLD LOWS AROUND 60...WITH LOW 50S ALONG THE LAKE.

SUNDAY AND SUNDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

WILL RAISE PRECIPITATION CHANCES FROM WEST TO EAST SUNDAY
AFTERNOON/SUNDAY NIGHT AS FOCUS OF LOW-LEVEL JET SHIFTS INTO THE
STATE AS LOW DEEPENS TO THE WEST...THOUGH SOME MODEL DIFFERENCES
WITH TIMING AND NORTHWARD EXTENT OF JET. SOME OF THE MODELS INDICATE
THE POTENTIAL OF AN MCS DEVELOPING OVER EASTERN IOWA AND MOVING
ACROSS SOUTHERN WISCONSIN OVERNIGHT. OVERNIGHT LOWS IN THE LOW TO
MID 60S AWAY FROM THE LAKE...WITH LOW TO MID 50S ALONG THE LAKE.

HIGHER DEW POINT AIR ADVECTING INTO THE REGION WILL BE CHILLED BY
COOL ONSHORE FLOW SO HAVE ADDED FOG TO LAKESHORE AREAS FOR
SUNDAY/SUNDAY NIGHT. FOG EXPECTED TO PUSH OFFSHORE MONDAY WITH MORE
SOUTH TO SOUTH-SOUTHWEST WINDS.

MONDAY AND MONDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

CWASP AND CIPS ANALOGS TARGETING MONDAY INTO MONDAY NIGHT FOR A GOOD
POTENTIAL FOR SEVERE THUNDERSTORMS IN THE REGION WITH WARM MOIST
UNSTABLE FLOW AHEAD OF CLOSED LOW TO THE WEST. NAM BUFKIT SOUNDINGS
WITH FORECASTED MID-60 DEW POINTS AND HIGHS AROUND 80 ARE PRODUCING
SURFACE-BASED CAPE OF 1000-1300 J/KG...WITH GFS CLOSER TO 2000 J/KG
AND 0-6 BULK SHEAR OF 40-50 KNOTS. BUT CAPE PREDICATED ON MUCH
HIGHER SURFACE DEW POINTS/LOW 70S/. GFS AND ECMWF ARE MORE BULLISH
WITH SEVERE POTENTIAL FOR SOUTHERN WISCONSIN PER CWASP PROBABILITIES
AT 00Z TUE...WITH THE DRY OCCLUSION ON THE NAM AND CANADIAN GEM
PUSHING POTENTIAL FARTHER TO THE SOUTH AND SOUTHWEST...CLOSER TO THE
SPC DAY 4 AREA. WILL CONTINUE MENTION OF SEVERE POTENTIAL IN THE
HWO.

.LONG TERM...TUESDAY THROUGH FRIDAY. FORECAST CONFIDENCE LOW TO
MEDIUM.

MODELS STILL STRUGGLING WITH THE TIMING AND TRACK OF CLOSED SYSTEM
ACROSS WESTERN GREAT LAKES. GFS IS FASTER TAKING THE SURFACE LOW
THROUGH THE REGION...WITH ANOTHER WAVE DEVELOPING AND LIFTING NE
THROUGH ILLINOIS TUE NIGHT AND WEDNESDAY...WITH PRECIPITATION ENDING
THURSDAY MORNING WITH HIGH PRESSURE NOSING IN.  ECMWF AND GEM DRIFT
A BROADER/WEAKER LOW ACROSS THE REGION...WITH THE HIGH NOT BUILDING
IN UNTIL OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. WILL KEEP
LIKELY/HIGH CHANCE POPS GOING INTO WEDNESDAY NIGHT...THEN TAPER OFF
THURSDAY.

&&

.AVIATION/00Z TAFS/...

SHOWERS FROM JUNEAU TO WEST BEND AND NORTH WILL SLOWLY MOVE OFF TO
THE NORTH AND DISSIPATE LATE THIS EVENING. THESE ARE ASSOCIATED WITH
AN UPPER LEVEL FRONT.

THERE IS A CHANCE THAT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL DEVELOP ONCE AGAIN SATURDAY AFTERNOON ALONG THE SURFACE
BOUNDARY WEST OF WAUKESHA...BUT AFFECTING MADISON AND JANESVILLE.
NOT SURE IF THUNDER WILL BE WIDESPREAD ENOUGH TO MENTION IN
TAF...BUT WILL OPT TO PUT IT IN FOR MSN.

CEILINGS AND VISIBILITY MAY DROP TO MVFR DURING RAIN SHOWERS...BUT
OTHERWISE VFR EXPECTED THROUGH THE PERIOD.

&&

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

$$

TONIGHT/SATURDAY AND AVIATION/MARINE...MRC
SATURDAY NIGHT THROUGH FRIDAY...REM