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000
FXUS63 KMKX 161450 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
950 AM CDT THU MAY 16 2013

.UPDATE...WINDS HAVE ALREADY TURNED ONSHORE ALONG THE LAKESHORE
THIS MORNING...WITH THE COOLER LAKE AIRMASS EXPECTED TO PUSH
INLAND THROUGH THE REMAINDER OF THE DAY. TEMPS HAVE WARMED QUICKLY
THIS MORNING...AND SHOULD STILL GET UP TO AROUND 80 WELL INLAND.
THE LAKE ENHANCED COLD FRONT SHOULD MAKE IT JUST ABOUT ALL THE WAY
THROUGH THE FORECAST BY THIS EVENING...WITH TEMPERATURES FALLING
QUITE A BIT BEHIND THE FRONT. WILL LIKELY SEE 50S ACROSS THE EAST
BY LATE AFTERNOON OR EVENING.

STILL A CHANCE THERE COULD BE A FEW SHOWERS THAT FORM ALONG THE
FRONT...PARTICULARLY NORTH OF MADISON WHERE THERE WILL BE A BIT
MORE MID LEVEL MOISTURE. WILL THUS LEAVE SLIGHT CHANCE POPS IN.

&&

.AVIATION/18Z TAFS/...VFR CONDITIONS WILL PERSIST THROUGH FRIDAY.
WINDS SHOULD TRANSITION TO EASTERLY BY MID OR LATE MORNING ACROSS
THE EASTERN FORECAST AREA...AND BY EVENING ACROSS THE WEST. THERE
COULD BE A FEW AFTERNOON AND EARLY EVENING SHOWERS ALONG THE
ADVANCING LAKE ENHANCE COLD FRONT...PRIMARILY NORTH OF MADISON.

THERE WILL BE A CHANCE FOR SHOWERS AND STORMS FRIDAY...THE BEST
CHANCE IN THE AFTERNOON FROM MADISON WESTWARD.

&&

.PREV DISCUSSION... /ISSUED 330 AM CDT THU MAY 16 2013/

SHORT TERM...

TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH

MAIN ISSUE FOR TODAY IS THE ARRIVAL OF A BACK DOOR COLD FRONT...
AFFECTIONATELY KNOWN AROUND HERE AS A PNEUMONIA FRONT.  THIS IS A
FRONT THAT WILL DEVELOP AS HIGH PRESSURE BUILDS AND PUSHES ACROSS
THE NORTHERN GREAT LAKES. THE RESULTANT NORTHEAST TO EAST WINDS WILL
PUSH RAPIDLY DOWN THE LAKE LATER THIS MORNING AND PUSH MUCH COOLER
LAKE AIR INLAND DURING THE AFTERNOON.  HIGHS IN THE EAST WILL BE
FELT EARLY IN THE DAY...WITH FALLING TEMPS THEREAFTER.  THE NAM/NCEP
4KM WRF AND HIRES NMM MODELS SUGGEST THE STRONG LOW LEVEL
CONVERGENCE COULD HELP GENERATE A FEW SHOWERS MAINLY NORTH OF
MADISON.  THIS WOULD BE LIGHT STUFF IF IT DEVELOPS.

THE COLDER AND DRIER AIR WILL ALLOW TEMPS TO COOL NICELY TONIGHT.
RETURN FLOW IN A DEVELOPING WARM ADVECTION PATTERN COULD RESULT IN
SOME LATE NIGHT THUNDERSTORMS WEST OF MADISON...THOUGH CONFIDENCE IS
RATHER LOW WITH THAT. MANY OF THE MODELS ARE DRY...HOLDING THE
ADVANCING PRECIP OFF UNTIL FRIDAY. WILL KEEP THE POPS VERY LOW AT
THIS POINT.

FRIDAY THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM.

UPPER LEVEL RIDGING WILL DOMINATE THE WESTERN GREAT LAKES REGION
THROUGH SUNDAY UNTIL AN AMPLIFIED...SLOW-MOVING UPPER TROUGH FINALLY
REACHES THE UPPER MIDWEST. WEAK SHORTWAVES EMBEDDED WITHIN THE RIDGE
ALONG WITH WEAK 700-850MB WARM AIR ADVECTION WILL BE THE SOURCE OF
SCATTERED SHOWER AND THUNDERSTORM ACTIVITY.

ONGOING CONVECTION OVER MN AND POSSIBLY WESTERN WI WILL LIKELY
SPREAD NORTHEASTWARD WITH THE 500MB SHORTWAVE AND 850MB BAROCLINIC
ZONE WHILE WEAKENING ON FRIDAY. SO WHILE THERE IS LIMITED POTENTIAL
FOR ANY THUNDERSTORMS TO DEVELOP OVER SOUTHERN WI FRI/FRI
NIGHT...ELEVATED SHOWERS AND THUNDERSTORMS MAY REACH ALL THE WAY TO
THE LAKE DESPITE THE LOW-LEVEL DRY EASTERLY FLOW. BY SATURDAY...ANY
THUNDERSTORM ACTIVITY WILL LIKELY BE NORTH OF THE FORECAST AREA BUT
MODELS CONTINUE TO SHOW A SHORTWAVE MOVING ACROSS SOUTHERN WI...SO
KEPT THE SLIGHT CHANCE OF STORMS IN THE FCST. DRY BY SAT NIGHT.

CLOUDS AND PERSISTENT EAST FLOW OFF THE LAKE WILL KEEP TEMPS COOLER
ON FRIDAY. THEN GENERAL WARMING TREND THROUGH THE WEEKEND.

LONG TERM...

SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM.

THE EASTWARD PROGRESSION OF THE AMPLIFIED UPPER TROUGH WILL STALL AS
IT REACHES THE UPPER MIDWEST SUNDAY AND MONDAY AND EVOLVES INTO A
CLOSED UPPER LOW OVER THE DAKOTAS/MN. THUNDERSTORM CHANCES WILL
INCREASE ACROSS SOUTHERN WI SUN NIGHT INTO MONDAY AS SHORTWAVES
ROTATING AROUND THE UPPER LOW AND INCREASING MOISTURE TRIGGER ROUNDS
OF CONVECTION.

SUNDAY COULD END UP DRY...WITH THE MORE LIKELY SCENARIO OF
THUNDERSTORMS TRIGGERING IN EASTERN IOWA AND TRACKING INTO SOUTHERN
WI SUNDAY EVENING DUE TO A STRONG SHORTWAVE CLOSE TO THE MAIN
SURFACE AND UPPER LOWS AND UPPER DIVERGENCE WITH A COUPLED JET.

IN TERMS OF INSTABILITY...GFS FORECAST SOUNDINGS FOR MONDAY/MON
NIGHT SHOW MODERATE CAPE AND STRONG LOW LEVEL SHEAR. THE DEWPOINTS
ARE OVERDONE WHICH WOULD LIMIT THE SURFACE-BASED CONVECTIVE
POTENTIAL...BUT IF THUNDERSTORMS COULD INITIATE...SEVERE WOULD BE
POSSIBLE. SPC HAS WEST CENTRAL IL HIGHLIGHTED IN THE DAY 6 SEVERE
WEATHER OUTLOOK.

TEMPS AND DEWPOINTS WILL BE ON THE RISE SO IT WILL BE HOT AND HUMID.
EXPECTING LOWER 80S SOUTH INLAND FROM THE LAKE. DEWPOINTS WILL
LIKELY GET INTO THE LOWER 60S. PRECIPITABLE WATER VALUES INCREASE TO
AROUND 1.25 INCHES WHICH IS AROUND 130 PERCENT OF NORMAL.

TUESDAY THROUGH THURSDAY...FORECAST CONFIDENCE LOW.

THE CHANCE FOR THUNDER WILL CONTINUE THROUGH WEDNESDAY AS SOUTHERN
WI REMAINS IN THE WARM SECTOR WITH THE CLOSED UPPER LOW OVER MN OR
IOWA. THE ECMWF THEN MOVES THAT CLOSED UPPER LOW SOUTHEAST ACROSS IL
WED NIGHT/THU WHICH WOULD ALLOW HIGH PRESSURE BACK INTO THE REGION
AND DRY BUT COOL WEATHER. THE GFS KEEPS IT PARKED OVER THE GREAT
LAKES AREA AND IT WEAKENS WHICH STALLS THE HIGH PRESSURE RIDGE OVER
THE PLAINS AND KEEPS SOUTHERN WI IN A SHOWERY BUT WARM PATTERN.

AVIATION/12Z TAFS/...

VFR CONDITIONS WILL PERSIST THROUGH THURSDAY. COULD SEE A FEW
SHOWERS MAINLY NORTH OF MADISON AND MILWAUKEE THIS AFTERNOON.
A BACK DOOR COLD FRONT WILL SWEEP IN FROM THE NORTHEAST LATER THIS
MORNING AS A STRENGTHENING NORTHEAST TO EAST WIND WILL PUSH DOWN THE
LAKE SHORE.  THIS OFTEN RESULTS IN AN ABRUPT AND GUSTY WIND SHIFT
FOR KMKE AND KENW.  WINDS TYPICALLY GUST RATHER HIGH FOR ABOUT AN
HOUR BEFORE BACKING DOWN RIGHT AWAY. CURRENT TIMING HAS WINDS
SHIFTING FROM NORTHWEST TO NORTHEAST AROUND 16Z-17Z THIS MORNING AT
KMKE AND ABOUT 17-18Z AT KENW/KUES.

MARINE...
ONLY CONCERN TODAY IS THE ABRUPT WIND SHIFT THAT WILL OCCUR OVER THE
LAKE SHORE THIS MORNING. WINDS WILL SHIFT QUICKLY FROM LIGHT
WESTERLY TO A SOMEWHAT GUSTY NORTHEAST THEN EAST DIRECTION DURING
THE MORNING HOURS.  THIS SHOULD OCCUR AROUND SHEBOYGAN BY 9-10
AM...REACHING MILWAUKEE BY 11-NOON.  WINDS AND WAVES ARE EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY LEVELS.

&&

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

$$

UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
FRIDAY THROUGH WEDNESDAY...MRC