Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KARX 091745
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1245 PM CDT WED JUL 9 2014

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 336 AM CDT WED JUL 9 2014

ANALYSIS OF WATER VAPOR LOOP AND RAP 500MB LEVEL SHOWING AN
ANOMALOUSLY DEEP LONGWAVE TROUGH CARVED OUT OVER THE GREAT
LAKES/MISSISSIPPI VALLEY REGION WHILE RIDGING CONTINUES OVER THE
WESTERN CONUS. A SHORTWAVE TROUGH WITHIN THE MAIN LONGWAVE TROUGH
WAS ROTATING SOUTHEAST THROUGH THE U.P. AND NORTHERN WI. RADAR
SHOWING SOME WEAK SHOWER ECHOES WITH THIS FEATURE. OTHERWISE...
TEMPERATURES ACROSS THE ARX FORECAST AREA WERE IN THE MIDDLE 50S TO
LOWER 60S WITH CALM TO LIGHT NORTHWEST WINDS UNDER PARTLY CLOUDY
SKIES.

FOR TODAY...LONGWAVE TROUGH BEGINS TO PUSH EAST TODAY TAKING COLDEST
POOL OF TEMPERATURE ALOFT WITH IT MORE INTO THE GREAT LAKES REGION.
NONETHELESS...FAIRLY STEEP LOW LEVEL LAPSE RATES REMAIN OVER THE
AREA MAINLY NORTHEAST OF I-94. BUFKIT SOUNDINGS SHOWING QUITE A BIT
OF CUMULUS ACROSS THAT AREA ALONG WITH THE POSSIBILITY OF SOME
SHOWERS. WILL KEEP A 20-30 PROBABILITY FOR THAT AREA. REST OF THE
AREA SHOULD SEE SCATTERED CUMULUS. OTHERWISE...LOOK FOR HIGHS IN THE
LOWER 70S ACROSS NORTH CENTRAL WI..TO THE MIDDLE AND UPPER 70S
ELSEWHERE.

FOR TONIGHT...HIGH PRESSURE BUILDS OVERHEAD FOR MOSTLY CLEAR AND
CALM CONDITIONS. THIS WILL SET UP GOOD RADIATIONAL COOLING ACROSS
THE AREA WITH LOWS TONIGHT DIPPING INTO THE MIDDLE/UPPER 40S IN THE
SAND/CRANBERRY COUNTRY OF CENTRAL WISCONSIN...AND IN THE 50S
ELSEWHERE. ALSO...AREAS OF FOG WILL BE LIKELY ACROSS THE LOWER LYING
AREAS/RIVER VALLEYS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 336 AM CDT WED JUL 9 2014

FOR THURSDAY THROUGH FRIDAY...

HIGH PRESSURE MOVES OFF TO THE EAST...SETTING UP RETURN/SOUTHERLY
FLOW ACROSS THE REGION ON THURSDAY. UNDER MOSTLY SUNNY SKIES LOOK
FOR HIGHS REBOUNDING INTO THE UPPER 70S TO THE LOWER 80S. DEW POINTS
WILL ALSO BE ON THE RISE THROUGH THE DAY FOR A SLIGHTLY MORE HUMID
FEEL.

ATTENTION THEN TURNS TO A MID-LEVEL TROUGH DROPPING SOUTHEAST FROM
THE NORTHERN PLAINS TOWARD THE UPPER MISSISSIPPI RIVER VALLEY REGION
THURSDAY NIGHT THROUGH FRIDAY WHILE A WARM FRONT SETS UP ACROSS THE
PLAINS INTO FAR SOUTHERN IA/CENTRAL IL. THIS WILL BRING A GOOD
CHANCE/LIKELIHOOD OF SHOWERS AND THUNDERSTORMS INTO THE AREA
CENTERED ON FRIDAY. THINKING ANY SEVERE THREAT SHOULD BE WELL SOUTH
OF THE AREA CLOSER TO NOSE OF 850MB MOISTURE TRANSPORT OVER THE
PLAINS WARM FRONT.

FOR SATURDAY THROUGH SUNDAY...

WILL CONTINUE TO SEE A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH
SATURDAY/SATURDAY EVENING AS A WEAK COLD FRONT MOVES IN AND STALLS
ACROSS THE AREA. GFS BUFKIT SHOWING 1000-2000J/KG OF MLCAPE ACROSS
THE AREA WITH 0-3KM BULK SHEAR IN THE 10-15KT RANGE IN THE BEST CAPE
POOL. SO...AN ISOLATED SEVERE PULSE-MODE STORM CANNOT BE RULED
OUT...BUT WIDESPREAD SEVERE NOT EXPECTED AT THIS TIME.

SHOWER/THUNDERSTORM CHANCES CONTINUE THROUGH SUNDAY AS WELL AS A MID-
LEVEL TROUGH/SURFACE TROUGH DROPS OUT OF SOUTHERN CANADA/NORTHERN
PLAINS TOWARD THE AREA. GFS A BIT FASTER WITH THIS FEATURE THAN THE
ECMWF...SO TIMING NOT SET IN STONE. GFS SHOWING MLCAPE IN THE 1000-
1500J/KG RANGE WITH A LITTLE BETTER 0-3KM SHEAR AROUND 20KT. WILL
HAVE TO KEEP AN EYE ON THE TIMING OF THIS FEATURE AND SEVERE THREAT.

FOR MONDAY INTO TUESDAY...COOLER AIR FILTERS INTO THE AREA AS AN
ANOMALOUSLY DEEP CLOSED LOW DROPS SOUTH OUT OF CANADA TOWARD THE
REGION. WILL HAVE TO KEEP A CLOSE WATCH ON THUNDERSTORM THREAT
MONDAY WITH TIMING OF INCOMING SHORTWAVE TROUGH ENERGY/LEADING EDGE
OF COLDER AIR DURING PEAK HEATING. TUESDAY LOOKING LIKE A
COOL/CLOUDY/POSSIBLY SHOWERY DAY AS DEEP CLOSED LOW/COLD POOL ALOFT
SETTLES OVER THE AREA.

TEMPERATURE-WISE...EXPECTING TEMPERATURES IN THE UPPER 70S/LOWER 80S
ON SUNDAY...THEN COOLING INTO THE UPPER 60S/LOWER 70S BY TUESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1245 PM CDT WED JUL 9 2014

CUMULUS FIELD HAS DEVELOPED ACROSS MUCH THE REGION AND WILL
PERSIST THROUGH THE AFTERNOON HOURS AT 3-6KFT. ANY SHOWERS THAT
DEVELOP ARE EXPECTED TO STAY OFF TO THE EAST OF THE TAF SITES.
SKIES WILL CLEAR OUT TONIGHT AS A RIDGE OF HIGH PRESSURE MOVES IN
FROM THE WEST. SOME VALLEY FOG IS POSSIBLE AT LSE...BUT SOME MID
LEVEL CLOUDS MAY BE MOVING IN ALONG WITH SOME STRONGER LOW LEVEL
WINDS...SO CONFIDENCE WAS NOT HIGH ENOUGH TO PUT ANY REDUCTIONS
INTO THE FORECAST.

&&

.HYDROLOGY...
ISSUED AT 336 AM CDT WED JUL 9 2014

THE MISSISSIPPI RIVER LEVEL CONTINUES TO FALL. MCGREGOR AND
GUTTENBERG IOWA ARE THE ONLY ARX FORECAST POINTS THAT REMAIN IN
FLOOD. THESE POINTS ARE EXPECTED TO FALL BELOW FLOOD STAGE BY
THURSDAY. FOR THE CURRENT AND FORECAST RIVER LEVELS...SEE OUR
INTERNET PAGE AT WWW.WEATHER.GOV/LACROSSE.

&&

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

$$

SHORT TERM...DAS
LONG TERM...DAS
AVIATION...HALBACH
HYDROLOGY...DAS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.