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000
FXUS63 KARX 131745
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1245 PM CDT THU JUN 13 2013

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 258 AM CDT THU JUN 13 2013

WATER VAPOR IMAGERY/RAP 500MB ANALYSIS THIS MORNING HAS THE
MID-LEVEL TROUGH THAT WAS RESPONSIBLE FOR THE ACTIVE WEATHER THIS PAST
AFTERNOON/EVENING NOW OVER MOVING INTO THE GREAT LAKES/OHIO RIVER
VALLEY REGION. MEANWHILE...HIGH AMPLITUDE RIDGE OF HIGH PRESSURE
MOVING ACROSS THE INTERMOUNTAIN WEST INTO THE PLAINS. AT THE
SURFACE...HIGH PRESSURE WAS NOSING INTO THE AREA FROM MANITOBA WITH
MUCH DRIER AIR. DEW POINTS ON NORTHERLY WINDS WERE IN THE UPPER 40S
ACROSS NORTHERN/CENTRAL MN AND NORTHERN WI. OTHERWISE...IR IMAGERY
WAS SHOWING WIDESPREAD MAINLY MID-CLOUD ACROSS THE AREA WITH
TEMPERATURES IN THE UPPER 50S TO THE MIDDLE 60S.

FOR TODAY...FINALLY SOME DRIER/PLEASANT WEATHER ON TAP AS HIGH PRESSURE
BUILDS OVER THE AREA. LOOK FOR MOSTLY SUNNY SKIES WITH HIGHS IN THE
70S AND NORTH WINDS IN THE 10-15 MPH RANGE. DEW POINTS AND RESULTANT
HUMIDITY TODAY WILL BE NOTICEABLY LOWER AS WELL THAN ON WEDNESDAY.

THE RIDGE WILL HOLD IN PLACE THROUGH TONIGHT AS A TROUGH OF LOW
PRESSURE AND COLD FRONT PUSH EAST OUT OF THE INTERMOUNTAIN WEST.
OTHER THAN A FEW HIGH/MID CLOUDS FROM CONVECTIVE DEBRIS OVER THE
PLAINS DRIFTING INTO THE AREA THROUGH THE RIDGE...MOSTLY CLEAR SKIES
EXPECTED TO RESULT WITH OVERNIGHT LOWS IN THE UPPER 40S TO THE MIDDLE
50S.

PLAN ON INCREASING CLOUDS FRIDAY...WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS WEST OF THE MISSISSIPPI LATER IN THE AFTERNOON. THIS IS
IN RESPONSE TO INCREASING ISENTROPIC LIFT AND 850MB MOISTURE
TRANSPORT IN ADVANCE OF THE COLD FRONT PUSHING INTO THE PLAINS. THIS
CONVECTION WILL BE BATTLING DRY AIR IN PLACE TO THE EAST AND AS A
RESULT...VERY ELEVATED IN NATURE. NAM SHOWING 1-6KM MUCAPE IN THE
400-800J/KG RANGE...SO STORMS EXPECTED TO REMAIN BELOW SEVERE
LIMITS. OTHERWISE...PLAN ON HIGH TEMPERATURES IN THE 70S.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 258 AM CDT THU JUN 13 2013

FRIDAY NIGHT INTO SATURDAY WILL HAVE TO BE WATCHED CLOSELY FOR SEVERE
WEATHER THREAT. MODELS CONTINUE TO DRAG THE COLD FRONT INTO THE AREA
WITH A TRIPLE POINT OF SORTS DEVELOPING ACROSS IA WITH A WARM FRONT
EXTENDING APPROXIMATELY ALONG I-80. MODELS IN GOOD AGREEMENT IN
FAIRLY STRONG 850MB MOISTURE TRANSPORT OVER THE WARM FRONT FOCUSING
INTO NORTHEAST IA/SOUTHWEST WI AFTER MIDNIGHT FRIDAY NIGHT. NAM
SHOWING 1-6KM MUCAPE IN THE 2000-3200J/KG RANGE ALONG THE MN/IA
BORDER INTO FAR SOUTHWEST WI...MAINLY SOUTH OF I-90. WITH 25-30KT
1-6KM BULK SHEAR...THIS MAY BE ENOUGH FOR SOME ORGANIZED ELEVATED
THUNDERSTORM  ACTIVITY WITH HAIL AND DAMAGING WIND THREAT...ALONG
WITH HEAVY RAINFALL/LOCALIZED FLOODING POTENTIAL AS PRECIPITABLE
WATER VALUES CREEP BACK UP INTO THE 1.5 TO 2 INCH RANGE. MODELS THEN
HAVE THE MOISTURE TRANSPORT/BETTER CAPE AXIS SHIFTING SOUTH AND EAST
OF THE AREA BY SATURDAY AFTERNOON...TAKING THE SEVERE/LOCALIZED
FLOODING THREAT WITH IT.

FOR SATURDAY NIGHT THROUGH SUNDAY...THE AREA WILL BE IN A FAST HIGH
ZONAL FLOW ALOFT WITH PERHAPS A COUPLE EMBEDDED WEAK SHORTWAVE
TROUGHS. THIS...COMBINED WITH SOME WEAK LINGERING INSTABILITY IS
ENOUGH TO WARRANT A LOWER-END SHRA/TS CHANCE. OTHERWISE...HIGHS ON
SUNDAY EXPECTED TO CLIMB INTO THE UPPER 70S/LOWER 80S.

MODELS IN GOOD AGREEMENT IN DROPPING A FAIRLY VIGOROUS MID-LEVEL
TROUGH SOUTHEAST ACROSS THE AREA IN THE SUNDAY NIGHT/MONDAY TIME
FRAME FOR A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS. SLIGHTLY
COOLER TEMPERATURES WILL RESULT MONDAY WITH HIGHS DROPPING BACK INTO
THE MID/UPPER 70S.

ECMWF/GFS IN VERY GOOD AGREEMENT IN BUILDING A RIDGE INTO THE AREA
TUESDAY THROUGH WEDNESDAY FOR A RAIN-FREE PERIOD WITH HIGHS IN THE
MID/UPPER 70S TUESDAY...WARMING INTO THE UPPER 70S/LOWER 80S ON
WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1244 PM CDT THU JUN 13 2013

SCATTERED INSTABILITY CUMULUS CLOUDS WILL GRADUALLY DEVELOP
ACROSS THE AREA THIS AFTERNOON. WITH THE LOSS DIURNAL HEATING LATE
THIS AFTERNOON AND EARLY EVENING...SKIES WILL BECOME CLEAR AND THE
SURFACE WINDS WILL DROP TO 6 KNOTS OR LESS. WAS INITIALLY
CONCERNED WITH THE POTENTIAL OF VALLEY FOG TONIGHT. HOWEVER BUFKIT
SOUNDINGS SHOW THAT THE LOWEST 1 KM WILL REMAIN WELL MIXED.

ON FRIDAY MORNING...THE MID AND HIGH CLOUDS WILL GRADUALLY
INCREASE FROM THE WEST AS A CONVECTIVE DEBRIS CLOUDS SPILL OVER
THE TOP OF RIDGE LOCATED OVER THE CENTRAL PLAINS.

&&

.HYDROLOGY...(FOR FRIDAY NIGHT INTO SATURDAY MORNING)
ISSUED AT 258 AM CDT THU JUN 13 2013

WILL BE WATCHING FRIDAY NIGHT INTO SATURDAY MORNING CLOSELY FOR THE
LIKELIHOOD OF ANOTHER ROUND OF THUNDERSTORMS ALONG WITH THE
POTENTIAL OF EXCESSIVE RAINFALL WITH LOCALIZED FLOODING. THE AREA
THAT LOOKS MOST SUSCEPTIBLE WILL BE ACROSS PORTIONS OF NORTHEAST IA
INTO FAR SOUTHWEST WI THAT WAS ALREADY HIT PRETTY HARD THIS
WEDNESDAY AFTN/EVENING WITH HEAVY RAINFALL. WITH NEARLY SATURATED
SOILS...THESE AREAS WILL HAVE TO STAY TUNED TO THE LATEST FORECAST
FOR FLOODING POTENTIAL.

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BOYNE
HYDROLOGY....DAS