National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KARX 152248
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
545 PM CDT SAT JUN 15 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 330 PM CDT SAT JUN 15 2013

LATEST RADAR SHOWED A LINE OF SHOWERS AND ISOLATED THUNDERSTORM
MOVING ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA AND WAS
WEAKENING RAPIDLY AS IT APPROACHED THE MISSISSIPPI RIVER.
SCATTERED THUNDERSTORMS WERE ONGOING ACROSS PORTIONS OF NORTH
CENTRAL AND NORTHWEST WISCONSIN. SURFACE OBSERVATIONS INDICATED A
WEAK COLD FRONT EXTENDING FROM SUPERIOR WISCONSIN...SOUTH TO RED
WING MINNESOTA TO AROUND AUSTIN MINNESOTA AND WAS GRADUALLY MOVING
EAST. A WEAKENING MCV WAS MOVING ACROSS THE FORECAST AREA AND WAS
SUPPORTING THE SHOWER/STORM ACTIVITY.

LATEST MESOSCALE ANALYSIS SHOWS 1500 TO 2000 J/KG OF SURFACED
BASED CAPE LINGERING ACROSS MUCH OF THE FORECAST AREA WITH AROUND
100 J/KG OF CIN. WILL HAVE TO KEEP A VERY CLOSE EYE ON THE
CLEARING BEHIND THE MCV TO SEE IF ADDITIONAL SHOWERS AND STORMS
WILL DEVELOP ALONG THE COLD FRONT. 0-6KM SHEAR IS INCREASING
BEHIND THIS FEATURE AS A 500 MB JET SAGS SOUTH INTO THE AREA. THE
FORECAST AREA ALSO IN PROXIMITY TO THE RIGHT ENTRANCE REGION OF A
250 MB JET STRETCHING FROM EASTERN SOUTH DAKOTA THROUGH CENTRAL
MINNESOTA INTO CENTRAL ONTARIO. CANNOT RULE OUT AN ISOLATED STRONG
TO PERHAPS SEVERE THUNDERSTORM LATE THIS AFTERNOON. CURRENTLY
THERE ISN/T MUCH FOR CUMULUS DEVELOPMENT ALONG THE BOUNDARY IN THE
WAKE OF THE MCV SO THINKING OVERALL SEVERE THREAT IS QUICKLY
DIMINISHING. THE COLD FRONT SLIDES SOUTH OF THE FORECAST AREA THIS
EVENING AS HIGH PRESSURE BUILDS IN TONIGHT INTO SUNDAY MORNING.
PLAN ON QUIET AND PLEASANT WEATHER ON SUNDAY WITH HIGH
TEMPERATURES CLIMBING INTO THE LOWER TO MID 80S UNDER PARTLY TO
MOSTLY SUNNY SKIES.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 PM CDT SAT JUN 15 2013

A TROUGH IS EXPECTED TO DIVE SOUTHEAST OUT OF SOUTHERN
MANITOBA/CANADA LATE SUNDAY NIGHT THROUGH MONDAY. ALSO...A COLD
FRONT WILL SLIDE SOUTH JUST AHEAD OF THE TROUGH. THE FRONT LOOKS TO
MOVE FROM NORTH TO SOUTH ACROSS THE FORECAST AREA MONDAY AFTERNOON
INTO MONDAY EVENING. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP LATE SUNDAY NIGHT AND CONTINUE INTO MONDAY AS THE FRONT
AND UPPER TROUGH MOVES THROUGH THE REGION. IF THE SYSTEM SLOWS AND
INSTABILITY CAN BUILD AHEAD OF THE SYSTEM ON MONDAY...A FEW STRONG
TO SEVERE STORMS ARE POSSIBLE. FORECAST SOUNDINGS INDICATE A
RATHER DRY SUB CLOUD LAYER...WITH AN INVERTED V LOOK TO THE
SOUNDING. 0-6 KM BULK SHEAR VALUES OF 30 TO 35 KTS...AND 0-3KM
MUCAPE VALUES IN THE 1200 TO 1500 J/KG ALSO SUPPORT THE POTENTIAL
FOR SEVERE THUNDERSTORMS. THINKING THAT THUNDERSTORMS MONDAY
AFTERNOON MAY HAVE THE POTENTIAL TO PRODUCE DAMAGING WIND GUSTS
AND POSSIBLY LARGE HAIL. THE FRONT MOVES SOUTH OF THE FORECAST
AREA MONDAY EVENING AND SURFACE HIGH PRESSURE BUILDS IN QUICKLY IN
ITS WAKE. NORTHWEST FLOW ALOFT THEN SETS UP ACROSS THE UPPER
MIDWEST TUESDAY THROUGH WEDNESDAY AS A RIDGE BUILDS OVER THE
CENTRAL CONUS. WILL HAVE TO KEEP A CLOSE WATCH ON EMBEDDED
SHORTWAVES WITHIN THE FLOW...WHICH HAVE THE POTENTIAL TO PRODUCE
SHOWERS AND THUNDERSTORMS. THINKING THE SURFACE HIGH SHOULD WIN
OUT AND PROVIDE QUIET WEATHER TUESDAY INTO WEDNESDAY. PLAN ON
HIGHS ON TUESDAY IN THE LOWER TO MID 70S...THEN WARMING SLIGHTLY
ON WEDNESDAY WITH HIGHS CLIMBING INTO THE UPPER 70S. THE UPPER
RIDGE STARTS TO BREAK DOWN THURSDAY THROUGH FRIDAY WITH SEVERAL
EMBEDDED SHORTWAVES MOVING THROUGH IT. WARM SOUTHERLY FLOW SETS UP
AT THE SURFACE ON THURSDAY AS THE HIGH SLIDES OFF TO THE EAST AND
A SURFACE TROUGH DEVELOPS OVER THE CENTRAL/NORTHERN PLAINS. AN
ACTIVE PERIOD IS IN STORE FOR THE FORECAST AREA STARTING LATE
THURSDAY AND POTENTIALLY LASTING INTO THE WEEKEND. LOOKING AT THE
ECMWF SOLUTIONS FOR FRIDAY...A SEVERE WEATHER EVENT MAY OCCUR. A
LOT OF DETAILS TO SORT OUT YET...BUT THIS IS THE TIMEFRAME WHEN
CAPE AND SHEAR PROFILES WOULD SUPPORT SEVERE THUNDERSTORMS.
ALSO...A SHORTWAVE TROUGH IS EXPECTED TO MOVE ACROSS THE AREA AND
COULD TRIGGER THE SHOWERS/STORMS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 545 PM CDT SAT JUN 15 2013

TAF SITES SITTING BETWEEN AREAS OF SHRA/TS EARLY THIS EVENING. SOME
MESO MODELS SUGGEST PCPN COULD DEVELOP BETWEEN THIS SYSTEM BETWEEN
NOW AND 03Z...BUT NOT SOLD ON THIS. THERE IS SOME INSTABILITY AND
THE LATEST RAP POINTS TO SOME LOW LEVEL MOISTURE TRANSPORT TOO.
HOWEVER...NO HINTS OF ANY CU/ENHANCED CLOUDS ACROSS THE LOCAL AREA
PER LATEST SATELLITE IMAGERY. FRONTOGENETIC FORCING LIES
NORTH/SOUTH...WHERE THE CURRENT PCPN RESIDES. SO...WILL OPT FOR DRY
FOR THE EVENING HOURS.

EXPECT CLEARING SKIES LATER TONIGHT AS WEAK HIGH PRESSURE BUILDS IN.
DECOUPLING WINDS LEAD TO THOUGHTS OF FOG. LIGHTER SFC WINDS AT
KLSE...BUT RAP BUFKIT SOUNDINGS STIRRING AT 14 KTS BY 04Z AT 200 FT
AND BOUNDARY LAYER DOESN/T APPEAR OVERLY MOIST. SO...DON/T BELIEVE
FG/BR WILL BE A CONCERN OVERNIGHT. EXPECT VFR CONDITIONS THROUGH
MUCH OF THE DAY SUNDAY.

LATER SUNDAY NIGHT...THE BOUNDARY TO THE NORTH WILL SINK SOUTH WITH
SOME WEAK MOISTURE TRANSPORT ALONG IT. A FEW SHRA/TS COULD SPARK
ALONG THE BOUNDARY...AND COULD IMPACT KRST/KLSE AFTER 06Z. ACTIVITY
WILL LIKELY BE SCATTERED.


&&

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

$$

SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RIECK