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000
FXUS63 KARX 141755
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1255 PM CDT TUE MAY 14 2013

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 330 AM CDT TUE MAY 14 2013

WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWS A BROAD RIDGE OF HIGH
PRESSURE ACROSS THE CENTRAL CONUS. A MID-LEVEL SHORTWAVE TROUGH
MOVING ACROSS NORTHERN MT WAS SPARKING AN MCS OVER SOUTHEAST
SASKATCHEWAN AND NORTHERN ND. AT THE SURFACE...A WARM FRONT WAS
POSITIONED FROM JUST EAST OF THE MISSISSIPPI WITH TEMPERATURES AT 3
AM ACROSS THE AREA RANGING FROM THE UPPER 40S/LOWER 50S ACROSS NORTH
CENTRAL WI...TO THE MID 50S/NEAR 60 ACROSS THE REST OF THE AREA.

FOR TODAY...WILL SEE THAT WARM FRONT JUST EAST OF THE MISSISSIPPI
RIVER PUSH EAST ACROSS THE REST OF THE AREA BY LATER THIS MORNING.
WILL HAVE TO WATCH THAT MCS UPSTREAM THIS MORNING...BUT FAIRLY
CONFIDENT IT WILL STAY NORTH OF THE AREA OVER NORTHERN MN/UPPER
MICHIGAN GIVEN THE MOISTURE TRANSPORT/CORFIDI VECTORS.

MEANWHILE...A DRY LINE OF SORTS PUSHES EAST INTO NORTHEAST
IA/SOUTHEAST MN BY MID-AFTERNOON WITH INCREASING HEAT AND LOWERING
SURFACE DEW POINTS. IN ADDITION...HIGHER BASED 850-700MB MOISTURE
TRANSPORT AHEAD OF AN APPROACHING COLD FRONT BEHIND THE DRY LINE
WILL PRODUCE ACCAS AND ISOLATED TO SCATTERED SHRA/TS BY LATE THIS
AFTERNOON. NAM/EC DEPICTING 850-500MB MUCAPE IN THE 1000-1800J/KG
WHICH MAY LEAD TO SOME VIGOROUS HIGH-BASED CONVECTION WITH CLOUD
BASES AT OR ABOVE 700MB. THIS CONVECTION WILL THEN HAVE THE
POTENTIAL TO PRODUCE BRIEF ERRATIC WIND GUSTS AROUND 40
MPH...AND...WITH MOST PRECIPITATION EVAPORATING BEFORE REACHING THE
GROUND...SOME DRY LIGHTNING AS WELL. THE COMBINATION OF VERY LOW
RELATIVE HUMIDITY AND THIS CONVECTION HAVE AN IMPACT ON FIRE WEATHER
WHICH IS FURTHER DISCUSSED IN THE FIRE WEATHER SECTION BELOW.
OTHERWISE...LOOK FOR NEAR RECORD HIGHS TODAY ACROSS THE AREA WITH
READINGS RANGING FROM THE LOWER/MIDDLE 80S ACROSS CENTRAL
WISCONSIN...TO THE LOWER 90S ACROSS NORTHEAST IA/SOUTHEAST MN.

LOOK FOR THAT COLD FRONT AND SCATTERED SHOWER/TS ACTIVITY TO PUSH
SOUTHEAST ACROSS THE AREA THIS EVENING...AND THEN CLEARING OUT OF
THE AREA AFTER MIDNIGHT. PLAN ON LOWS OVERNIGHT IN THE 50S.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 AM CDT TUE MAY 14 2013

A WEAK RIDGE OF HIGH PRESSURE WILL DRIFT ACROSS THE REGION WEDNESDAY
THROUGH THURSDAY FOR DRY CONDITIONS. THE NAM DOES HINT AT A WEAK
MID-LEVEL TROUGH PROPAGATING EAST THROUGH THE RIDGE AND DOES PRODUCE
SOME MID-LEVEL MOISTURE AND LIGHT QPF FOR WEDNESDAY AFTN/EVE.
HOWEVER...IT IS THE ONLY MODEL DOING THIS...SO DISCOUNTED FOR NOW
BUT WILL HAVE TO BE WATCHED WITH 12Z MODEL RUN.

THEN FOR THURSDAY NIGHT INTO FRIDAY...WILL SEE AN INCREASE AGAIN IN
850-700MB MOISTURE TRANSPORT AND ISENTROPIC LIFT INTO THE REGION
AHEAD OF LOW PRESSURE MOVING OUT OF THE ROCKIES INTO THE HIGH PLAINS.
THIS WILL YIELD A CHANCE OF SHOWERS AND THUNDERSTORMS. HIGHS
EXPECTED TO TOP OFF IN THE MID/UPPER 70S ON THURSDAY...THEN COOLING
A FEW DEGREES ON FRIDAY WITH INCREASED CLOUD COVER/SCATTERED
PRECIPITATION.

FOR THE WEEKEND...GFS/ECMWF SHOW A DEEPENING MID-LEVEL TROUGH OVER THE
WEST WITH SURFACE LOW PRESSURE DEVELOPING OVER THE PLAINS AND
APPROACHING THE UPPER MISSISSIPPI RIVER VALLEY REGION. CONTINUED
MOISTURE TRANSPORT AHEAD OF THE TROUGH/LOW WILL PRODUCE AN EXTENDED
PERIOD FOR A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS. HIGH
TEMPERATURES LOOK TO REMAIN RIGHT AROUND NORMAL IN THE 70S.
THUNDERSTORM CHANCES CONTINUE INTO MONDAY WITH COLD FROPA. WILL HAVE
TO WATCH THIS WEEKEND CLOSELY AS EXACT DETAILS ON WHERE BEST
DYNAMICS SET UP ARE NOT CLEAR. THIS WOULD DETERMINE WHERE ANY SEVERE
THREAT WOULD ARISE. STAY TUNED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1255 PM CDT TUE MAY 14 2013

SOUTHWEST WINDS OF 14 TO 18 KTS ARE EXPECTED AT THE TAF SITES THROUGH
LATE THIS AFTERNOON. THE WINDS WILL GUST TO AROUND 30 KTS AT KRST
AND TO AROUND 24 KTS AT KLSE. A COLD FRONT WILL SLIDE ACROSS THE
TAF SITES LATE THIS AFTERNOON INTO THIS EVENING...POSSIBLY
GENERATING A FEW SHOWERS AND THUNDERSTORMS. CONFIDENCE ON THESE
IMPACTING THE TAF SITES IS LOW SO HAVE NOT INCLUDED THEM IN THE
TAFS AT THIS TIME. WINDS WILL DIMINISH INTO THE 7 TO 10 KT RANGE
LATE THIS EVENING AND SWITCH TO THE NORTHWEST BEHIND THE FRONT.
WEAK SURFACE HIGH PRESSURE IS EXPECTED TO BUILD IN LATE TONIGHT
INTO WEDNESDAY MORNING WITH VFR CONDITIONS EXPECTED. PLAN ON
NORTH/NORTHWEST WINDS INCREASING TO AROUND 12 KTS DURING THE MID
TO LATE MORNING HOURS ON WEDNESDAY.

&&

.FIRE WEATHER...TODAY
ISSUED AT 330 AM CDT TUE MAY 14 2013

VERY WARM PUSH OF AIR TODAY WITH VERY LOW SURFACE RELATIVE
HUMIDITIES BY THIS AFTERNOON ACROSS PORTIONS OF SOUTHEAST
MN/NORTHEAST IA. LOOKING FOR HIGHS ACROSS THAT AREA IN THE LOWER 90S
WITH RELATIVE HUMIDITY DIPPING INTO THE LOWER 20 PERCENT RANGE. ADD
IN GUSTY SOUTHWEST WINDS AND SOME FUELS NOT GREENED UP YET AND
WILDFIRE THREAT IS THE RESULT. IN ADDITION...SOME DRY THUNDERSTORMS
MAY BE SEEN LATER IN THE AFTERNOON AHEAD OF AN APPROACHING COLD
FRONT. THIS MAY RESULT IN ERRATIC WIND GUSTS AROUND 40 MPH AND DRY
LIGHTNING FOR PERHAPS SOME FIRE STARTS IF FUELS ARE RECEPTIVE
ENOUGH. FOR THIS REASON...WENT AHEAD AND ISSUED A RED FLAG WARNING
FROM NOON TODAY UNTIL 8 PM THIS EVENING FOR DODGE/MOWER COUNTIES IN
SOUTHEAST MN...AND MITCHELL/FLOYD COUNTIES IN NORTHEAST IA.

&&

.CLIMATE...TODAY
ISSUED AT 330 AM CDT TUE MAY 14 2013

RECORD HIGHS FOR REFERENCE FOR TODAY...MAY 14TH...GIVEN THE
UNSEASONABLE WARMTH FORECAST:

IOWA...

CHARLES CITY      93 IN 1932
DECORAH           94 IN 1940
FAYETTE           93 IN 1932

MINNESOTA...

ROCHESTER         94 IN 2007
AUSTIN            91 IN 2001
CALEDONIA         87 IN 1894
PRESTON           86 IN 1991

WISCONSIN...

LA CROSSE         93 IN 1932
PRAIRIE DU CHIEN  92 IN 1932
SPARTA            88 IN 1991
MEDFORD           87 IN 1991
RICHLAND CENTER   89 IN 1932
VIROQUA           90 IN 1932

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ086-094.

IA...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR IAZ008-018.

&&

$$

SHORT TERM.....DAS
LONG TERM......DAS
AVIATION...WETENKAMP
FIRE WEATHER...DAS
CLIMATE........AJ