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000
FXUS63 KMKX 141502 AAA
AFDMKX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1002 AM CDT TUE MAY 14 2013

.UPDATE...HAVE WARMED TEMPS IN THE SOUTHEAST THIS MORNING...AS IT
APPEARS THE SOUTHWEST WINDS WILL KEEP THE LAKE BREEZE AWAY A BIT
LONGER THAN ORIGINALLY ANTICIPATED. THIS WILL ALLOW THE 80 DEGREE
TEMPS TO PUSH FARTHER EAST...LIKELY REACHING MILWAUKEE TO KENOSHA.
FARTHER NORTH NEAR THE LAKE...THE WINDS WILL TURN ONSHORE
QUICKER...SO STILL EXPECTING COOLER TEMPS.

&&

.AVIATION/18Z TAFS/...VFR CONDITIONS WILL PERSIST THROUGH
WEDNESDAY. STILL LOOKS LIKE CHANCES FOR ANY SHOWERS OR STORMS ARE
QUITE LOW FOR THIS EVENING...AS THERE IS A LOT OF DRY AIR IN
PLACE. WILL THUS LIKELY MAINTAIN A DRY FORECAST FOR THE TAF SITES.

&&

.PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 14 2013/

SHORT TERM...

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

VERY LITTLE CHANGE TO THE GOING FORECAST FOR THIS PERIOD.
TEMPERATURES THIS AFTERNOON WILL CLIMB ABOUT 20 DEGREES ABOVE
YESTERDAY/S HIGHS.  TEMPS WILL BE HELD DOWN FROM THE BEACHES OF
KENOSHA...STRETCHING INLAND TO SHEBOYGAN AND FOND DU LAC COUNTIES
DUE TO A PERSISTENT SOUTH TO SOUTHEAST FLOW BRINGING COOLER LAKE AIR
IN. HIGHS WILL RANGE FROM THE UPPER 80S IN WESTERN IOWA/LAFAYETTE
COUNTIES...TO THE MID/UPPER 60S ALONG THE LAKE SHORE.

THE CHALLENGE FOR TONIGHT IS THE ARRIVAL OF A COLD FRONT LATER THIS
EVENING. THE PARENT LOW IS OVER SOUTHERN CANADA WITH A SECONDARY LOW
TRACKING ACROSS NORTHERN WISCONSIN...TRAILING THE CDFNT. THE MODELS
CONTINUE TO HAVE ERRORS WITH RESPECT TO BOUNDARY LAYER MOISTURE. THE
GFS STILL HAS DEWPOINTS CLIMBING INTO THE LOWER 70S AHEAD OF THE
FRONT OVER WESTERN WISCONSIN...WHEN IN REALITY THEY/LL BE ABOUT 15
DEGREES LOWER. THE NAM/ECMWF ARE PROBABLY 10 DEGREES TOO HIGH.
CURRENT THINKING IS THIS IS RELATED TO THE CLIMATOLOGICALLY LATE
GREEN UP AND LACK OF EVAPOTRANSPIRATION THE MODELS ARE EXPECTING.
WITH THOSE DEWPOINTS...A FEW MODELS WANT TO FIRE OFF CONVECTION. THE
GFS/NAM/SPC SREF ARE THE ONLY MODELS SHOWING ANY PRECIP. THE HIRES
ARW/NMM/ECMWF/NCEP 4KM WRF ARE DRY. CORRECTING FOR THE HIGH
DEWPOINTS DRAMATICALLY INCREASES THE CONVECTIVE INHIBITION. THE
SOUNDINGS ARE VERY DRY. ISENTROPICALLY...THE CONDENSATION PRESSURE
DEFICITS ARE HUGE.  WILL ONLY CARRY A SLIGHT CHANCE OF THUNDERSTORMS
THIS EVENING WEST OF MADISON...BUT THIS IS MORE OF A COLLABORATION
NOD TO OFFICES UPSTREAM THAT HAVE HIGHER POPS.  THE FRONT WILL
LIKELY COME THROUGH DRY.

WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE HIGH

WINDS WILL BE BRISK OUT OF THE NW IN THE WAKE OF THE SURFACE TROUGH
WED MORNING. THE PRESSURE GRADIENT AND RESULTING WINDS WILL WEAKEN
DURING THE AFTERNOON AS HIGH PRESSURE NOSES INTO THE GREAT LAKES
REGION. EXPECTING A LATE AFTERNOON LAKE BREEZE TO DEVELOP AND REMAIN
NEAR THE LAKESHORE...THUS WARM TEMPS ALL THE WAY TO THE SHORELINE.

ZONAL FLOW ALOFT WILL ALLOW TEMPS TO REBOUND QUICKLY BEHIND THE
SURFACE TROUGH/COLD FRONT ON WED. LEANED TOWARD MOS GUIDANCE FOR
HIGHS IN THE UPPER 70S TO AROUND 80.

HIGH PRESSURE ALOFT AND AT THE SURFACE WILL ALLOW FOR LIGHT WINDS
AND A LAKE BREEZE ON THU. INLAND TEMPS WILL BE VERY SIMILAR TO WED
HIGHS...BUT LAKESHORE TEMPS WILL BE COOLER.

SOME MODELS ARE SUGGESTING LIGHT QPF OVER SOUTHERN WI AT TIMES WED
AND THU DUE TO A WEAK 500MB SHORTWAVE AND THE RIGHT ENTRANCE REGION
OF AN UPPER JET...BUT WILL DISREGARD THAT GIVEN THE DRY AIR IN THE
LOW LEVELS AND MODEL HIGH MOISTURE BIAS.

LONG TERM...

THURSDAY NIGHT THROUGH SATURDAY NIGHT...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 ON SUNDAY. IT IS FORECAST TO CLOSE OFF
OVER THE REGION AND STALL HERE UNTIL AT LEAST THE MIDDLE OF NEXT
WEEK.

WEAK WARM AIR ADVECTION AND SUBTLE SHORTWAVE ENERGY MAY BE ENOUGH TO
PRODUCE RANDOM ELEVATED THUNDERSTORMS THU NIGHT THROUGH SAT
NIGHT...THUS THE SMALL CHANCE FOR THUNDER IN EVERY PERIOD. LOW
CONFIDENCE IN ANY PRECIP AT A GIVEN LOCATION.

TEMPS WILL CONTINUE TO BE WARM IN THE UPPER 70S AHEAD OF THIS
UPPER LOW WITH 925MB TEMPS IN THE 16 TO 20C RANGE. HOWEVER...
EASTERLY COMPONENT TO THE WINDS WILL KEEP LAKESHORE TEMPS COOLER.

SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM.

THE BETTER CHANCE FOR THUNDERSTORMS IN SOUTHERN WI WILL BE ON SUNDAY
AS THE SURFACE LOW MOVES INTO MN AND THE UPPER TROUGH TAKES ON A
NEGATIVE TILT. THE CHANCE FOR THUNDER WILL CONTINUE UNTIL MONDAY
WHEN THE INITIAL SURFACE TROUGH MOVES THROUGH SOUTHEAST WI. THEN
SHOWER CHANCES WILL REMAIN OVER SOUTHERN WI UNTIL THAT UPPER TROUGH
MOVES OUT...WHICH MAY BE TOWARD THE END OF NEXT WEEK. THE 00Z ECMWF
NOW SHOWS THE POSSIBILITY FOR THUNDER CONTINUING INTO THE MIDDLE OF
NEXT WEEK.

AVIATION/12Z TAFS/...VFR THROUGH THE PERIOD.  A TROUGH OF LOW
PRESSURE AND COLD FRONT WILL BE PUSHING IN LATER THIS AFTERNOON AND
TONIGHT. WINDS AT KMKE WILL LIKELY TURN SOUTHEAST FOR A TIME THIS
AFTERNOON...BUT TURN BACK TO THE SOUTHWEST AS THE TROUGH APPROACHES.
THE TROUGH IS EXPECTED TO COME THROUGH DRY.  LOOK FOR THE FRONT TO
PASS THROUGH KMSN AROUND 07Z AND KMKE BETWEEN 10-12Z.

&&

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

$$

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