000
FXUS63 KARX 191147
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
647 AM CDT SUN MAY 19 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT SUN MAY 19 2013

IT STILL APPEARS AMPLE INSTABILITY WILL BE AROUND BY AFTERNOON
OVER THE FORECAST AREA....HOWEVER A CLEAR TRIGGER AND FOCUS FOR
THUNDERSTORMS AND SEVERE WEATHER IS STILL NOT CLEAR.

AT 08Z THE HIGH PLAINS CONVECTION CONTINUES TO SHIFT EAST ACROSS
IA...BEING FUELED BY A MARITIME TROPICAL AIR MASS SURGE AS
PRESSURES FALL IN RESPONSE TO THE INITIAL SHORTWAVE TROUGH
EJECTING NORTH FROM THE LONG WAVE TROUGH OVER THE INTERMOUNTAIN.
CURRENTLY THE TROUGH IS OVER NERN CO PER GOES WATER VAPOR IMAGERY.
ANOTHER PIECE OF ENERGY IS OVER THE WRN TX PANHANDLE AND WILL
ARRIVE THIS EVENING. 00Z RAOB DATA INDICATES THAT MARITIME
TROPICAL AIR MASS WELL...WITH AN AXIS OF 1.25 TO 1.50 INCH
PRECIPITABLE WATER VALUES FROM OMAHA TO SPRINGFIELD /170 PERCENT
NORMAL/. THIS IS COMPARED TO 1.00 TO 1.25 INCHES MSP-DVN. THIS AIR
MASS ARRIVES OVER THE FORECAST AREA TODAY WITH SURFACE DEWPOINTS
THE HIGHEST OF THE YEAR...IN THE MIDDLE TO UPPER 60S. 88D WIND
PROFILERS SHOWING AN INCREASING LOW- LEVEL JET ACROSS
IA...CONVERGING INTO MN. THIS TRAJECTORY IS NOT LIFTING
ADIABATICALLY HOWEVER...WITH LITTLE TEMPERATURE GRADIENT THROUGH
THAT AREA. THE CONVERGENCE AND INSTABILITY IS FUELING THE STORMS.
A FEW WARNINGS HAVE BEEN ISSUED RECENTLY FOR HAIL. WIND SHEAR IS
WEAKER SO ISOLATED LARGE HAIL IS REALLY ALL WE WOULD EXPECT.

HAVE BEEN MONITORING THE HRRR RUNS ALL EVENING AND UNTIL THE
19.03Z RUN...A VERY CONSISTENT SIGNAL WAS PRESENT OF BRINGING THE
CONVECTION INTO THE WRN FORECAST AREA AROUND 12Z. HAVE SLOWLY
STEPPED UP THE RAIN CHANCES BASED ON THE LOW-LEVEL JET AND
MOISTURE TRANSPORT CONVERGENCE IN CONCERT WITH INCREASING CAPE AS
THAT MOIST AIR MASS BEGINS ITS INFLUENCE. CURRENTLY MUCAPES OF
AROUND 1000 J/KG ARE WEST OF THE MISS RIVER...BUT THIS IS LIKELY
TO INCREASE OVERNIGHT AND PROBABLY BE IN THE 1300 J/KG RANGE BY
DAWN.

THE MOISTURE SURGE AND TRANSPORT SHIFT NORTHWARD AND BEGIN WHAT
APPEARS TO BE A LONGER TERM FOCUS OF CONVERGENCE NORTHWEST OF THE
FORECAST AREA. THIS AFTERNOON IT APPEARS THE MODEL GUIDANCE IS
CONSISTENT IN A FAIRLY UNIFORM SOUTHEAST FLOW OVER THE FORECAST
AREA...WITH CONVERGENCE ACROSS NRN WI TO CENTRAL MN...ALONG THE
STATIONARY BOUNDARY. WITH VERY HIGH MOISTURE IN PLACE AND SOME
HEATING...WE WILL BUILD SOME HIGHER MLCAPES AROUND 1800 J/KG
QUICKLY /MAYBE 3000 J/KG SBCAPE/. THIS USING A 67F DEWPOINT.

THE WIND SHEAR OVER THE AREA HAS BEEN CONSISTENTLY FORECAST BELOW
SUPERCELL THRESHOLDS THIS AFTERNOON WITH MOST OF THE SHEAR A
MODERATE 30-35KTS FROM 0-3KM AND LITTLE INCREASE ABOVE. THIS WOULD
FAVOR COLD POOL SYSTEMS AND BOWING WIND SEGMENTS. THE 19.00Z NAM
IS A BIT OF AN OUTLIER SUGGESTING STRONGER WINDS ALOFT FURTHER
NORTH...IN THE SUPERCELL RANGE. HAVE STAYED THE COURSE WITH A
WEAKER GRADIENT ALOFT WITH THE LOW CENTER STILL FAR WEST. SO THE
THREATS CONTINUE TO BE DAMAGING WIND AND LARGE HAIL. FLASH
FLOODING COULD ALSO BE A PROBLEM...SEE HYDROLOGY SECTION. AN
ISOLATED TORNADO IS POSSIBLE TOO.

THE MAIN PROBLEM RIGHT NOW SEEMS TO BE THE LACK OF A GOOD TRIGGER
THIS AFTERNOON. THE BOUNDARY LAYER FLOW IS A UNIFORM SOUTHEAST AND
LITTLE CONVERGENCE IS SEEN IN THE AREA. THUS...ANY BOUNDARY THAT
DOES PRESENT ITSELF COULD TRIGGER INITIATION AS THERE WILL BE NO
CAP IN PLACE. WITH SUCH VIGOROUS CONVECTION IN KS/OK...UPSTREAM OF
THE AREA...WE COULD SEE A CONVECTIVE VORTICITY MAX APPEAR IN THE
FLOW AND POSSIBLY BECOME AN INITIATOR. THE HRRR AND HI RES NMM SEEM
TO BE HINTING AT THIS SOLUTION LATER AFTERNOON.

THIS EVENING...AS STRONG ENERGY ROTATES NORTHEAST...CURRENTLY IN
WEST TX...THE LOW-LEVEL JET IN THE 19.00Z NAM EXCITES AND A NICE
CONVERGENT LOW-LEVEL JET DEVELOPS CONVECTION OVER IOWA AND MOVES
IT NORTHWARD. THE 19.00Z GFS DOES NOT AGREE ON THIS WITH ITS FOCUS
NORTH AGAIN ON THE NWRN WI-CENTRAL MN BOUNDARY. BUT THE HI RES 00Z
RUNS...USING THE NAM AS INITIALIZATION AND BOUNDARY
CONDITIONS...BRING WIDESPREAD CONVECTION IN FROM IA. THERE IS
BETTER JET DYNAMICS AND TRANSPORT IN THE NAM..AND THIS SEEMS
REASONABLE...THUS..HAVE CONTINUED TO HIT THE EVENING
HARD...EVOLVING THE WEATHER NORTH BY MORNING. THE 19.00Z GEM AND ECMWF
AGREE WELL WITH THIS SCENARIO. SO...LOOKING FOR A WET OVERNIGHT.
THERE IS STILL INSTABILITY OVERNIGHT...2K MUCAPE...AND A BIT
BETTER SHEAR.

BOTTOM LINE IS THAT THE DAYTIME HOURS MAY BE PRETTY CLEAN BECAUSE
OF LACK OF A THUNDERSTORM TRIGGER. IF AN MCV FROM OK/KS CAN
DEVELOP TSRA AND THE TSRA CAN ROOT ITSELF IN THE BOUNDARY LAYER
OVER IA...OR SOME BOUNDARY EXISTS...CHANCES INCREASE FOR AFTERNOON
SEVERE WEATHER...AS THE AIR MASS WILL BE WEAKLY CAPPED. THIS
EVENING SEEMS TO PROMOTE INCREASING RAIN AND THUNDERSTORMS WITH
STILL SOME SEVERE POTENTIAL UNTIL THE CAPE IS USED UP...BUT NOT
QUITE AS WIDESPREAD AS AN AFTERNOON EVENT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 318 AM CDT SUN MAY 19 2013

AS THE LOW DRAWS CLOSER MONDAY...SHEAR INCREASES TO SUPERCELL
STRENGTH...BUT AGAIN IT MAY BE DIFFICULT TO IDENTIFY A TRIGGER
WITH LITTLE SURFACE BOUNDARY ACTION IN THE AREA. THE STATIONARY
BOUNDARY REMAINS TO THE NW WITH THE BEST CONVERGENCE. HOWEVER...WITH
THE SURFACE LOW EXPECTED TO BE NEAR KFSD...AND AMPLE MLCAPE AGAIN
NEAR 2000 J/KG...STORMS LOOK TO FORM TO THE WEST AND MOVE INTO THE
AREA TUESDAY EVENING. HOWEVER...THIS PATTERN IS SO UNCAPPED AND
UNSTABLE...WE FOUND IT HARD TO GET DETAILED ON TIMING ANYWHERE.
MONDAY STILL HAS THE POTENTIAL FOR SEVERE WEATHER...AND IT LOOKS
LIKE THE EVENING HOURS. WITH INCREASED WIND SHEAR...ROTATING
STORMS ARE POSSIBLE AND THUS LARGE HAIL AND WIND. AN ISOLATED
TORNADO CANNOT BE RULED OUT BUT THE WIND ENVIRONMENT DOESNT LOOK
OVERLY FAVORABLE.

THE LOW CONTINUES TO SHIFT SLOWLY EAST AND PROVIDE RAIN THREATS
THAT ARE DIFFICULT TO TARGET THROUGH THURSDAY. SOME DRIER AIR BEGINS TO
SHIFT INTO THE AREA ON SOUTHWEST FLOW OFF THE ROCKIES ON
TUESDAY...AND SOMEWHAT COOLER AIR. THIS WILL END THE SEVERE
WEATHER THREAT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 646 AM CDT SUN MAY 19 2013

A WEAKENING LINE OF SHOWERS AND A FEW THUNDERSTORMS WILL MOVE INTO
WESTERN WISCONSIN AROUND 19.12Z. THIS LINE IS NOT CAUSING ANY
VISIBILITY RESTRICTIONS OR A WIND SHIFT. IN ADDITION...THE
CEILINGS WILL REMAIN VFR. MESO MODELS SUGGEST THAT SEVERAL LINES
OF SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE TAF SITES THIS
AFTERNOON AND TONIGHT. THE ONLY TIME PERIOD THAT SEEMS TO BE
CONSISTENT IN TIMING IS THE ONE THAT MOVES THROUGH BETWEEN 19.18Z
AND 19.21Z...SO INCLUDED SOME THUNDERSTORMS DURING THIS TIME
PERIOD. A FEW OF THESE STORMS MAY EVEN BECOME SEVERE WITH LARGE
HAIL AND DAMAGING WINDS BEING THE PRIMARY CONCERN. BEYOND THIS
TIME PERIOD...THE TIMING IS VERY INCONSISTENT...SO JUST WENT WITH
SHOWERS FOR NOW.

&&

.HYDROLOGY...
ISSUED AT 318 AM CDT SUN MAY 19 2013

HYDROLOGY...THE PROBABILITIES HAVE TIPPED TOWARD A FLASH FLOOD WATCH
FOR 3 PM TODAY THROUGH MONDAY. THERE ARE TOO MANY VARIABLES IN
PLAY THAT SUGGEST HEAVY RAINFALL AND FLOODING POTENTIAL INCLUDING
SOIL MOISTURE CENTERED OVER SERN MN ABNORMALLY HIGH...FRIDAYS
RAINFALL HAVING HIGHER END FLOODING OUTCOMES IN SERN
MN...PRECIPITABLE WATER VALUES OVER 150 PERCENT NORMAL MOVING
IN...SBCAPE BUILDING DURING THE DAY TO NEAR 3K /ML NEAR 1800/
BASED ON 67F DEW POINT...AND FORCING INCREASING DURING THE EVENING
WITH STRONGER MOISTURE TRANSPORT CONVERGENCE AND SHEAR MOVING INTO
THE AREA.

THIS FLASH FLOOD WATCH MAY BE EXPANDED AND POSSIBLY EXTENDED INTO
MONDAY NIGHT SHOULD DETAILS SUGGEST THE FLOODING THREAT COULD
REMAIN. THERE IS SOME SUGGESTION THAT THE VERY HIGH PRECIPITABLE
WATER MOIST CONVEYOR BELT WOULD SHIFT INTO WI AS A DRIER ROCKIES AIR
MASS ADVECTS IN ON SWRLY FLOW.

RIVERS IN THE WATCH AREA WOULD ALSO SEE RAPID RISES ASIDE FROM THE
FLASH FLOODING EFFECTS.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH FROM 3 PM CDT THIS AFTERNOON THROUGH MONDAY
     EVENING FOR MNZ079-086-087-094-095.

IA...FLASH FLOOD WATCH FROM 3 PM CDT THIS AFTERNOON THROUGH MONDAY
     EVENING FOR IAZ008.

&&

$$

SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...BOYNE
HYDROLOGY...BAUMGARDT

000
FXUS63 KARX 190818
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
318 AM CDT SUN MAY 19 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT SUN MAY 19 2013

IT STILL APPEARS AMPLE INSTABILITY WILL BE AROUND BY AFTERNOON
OVER THE FORECAST AREA....HOWEVER A CLEAR TRIGGER AND FOCUS FOR
THUNDERSTORMS AND SEVERE WEATHER IS STILL NOT CLEAR.

AT 08Z THE HIGH PLAINS CONVECTION CONTINUES TO SHIFT EAST ACROSS
IA...BEING FUELED BY A MARITIME TROPICAL AIR MASS SURGE AS
PRESSURES FALL IN RESPONSE TO THE INITIAL SHORTWAVE TROUGH
EJECTING NORTH FROM THE LONG WAVE TROUGH OVER THE INTERMOUNTAIN.
CURRENTLY THE TROUGH IS OVER NERN CO PER GOES WATER VAPOR IMAGERY.
ANOTHER PIECE OF ENERGY IS OVER THE WRN TX PANHANDLE AND WILL
ARRIVE THIS EVENING. 00Z RAOB DATA INDICATES THAT MARITIME
TROPICAL AIR MASS WELL...WITH AN AXIS OF 1.25 TO 1.50 INCH
PRECIPITABLE WATER VALUES FROM OMAHA TO SPRINGFIELD /170 PERCENT
NORMAL/. THIS IS COMPARED TO 1.00 TO 1.25 INCHES MSP-DVN. THIS AIR
MASS ARRIVES OVER THE FORECAST AREA TODAY WITH SURFACE DEWPOINTS
THE HIGHEST OF THE YEAR...IN THE MIDDLE TO UPPER 60S. 88D WIND
PROFILERS SHOWING AN INCREASING LOW- LEVEL JET ACROSS
IA...CONVERGING INTO MN. THIS TRAJECTORY IS NOT LIFTING
ADIABATICALLY HOWEVER...WITH LITTLE TEMPERATURE GRADIENT THROUGH
THAT AREA. THE CONVERGENCE AND INSTABILITY IS FUELING THE STORMS.
A FEW WARNINGS HAVE BEEN ISSUED RECENTLY FOR HAIL. WIND SHEAR IS
WEAKER SO ISOLATED LARGE HAIL IS REALLY ALL WE WOULD EXPECT.

HAVE BEEN MONITORING THE HRRR RUNS ALL EVENING AND UNTIL THE
19.03Z RUN...A VERY CONSISTENT SIGNAL WAS PRESENT OF BRINGING THE
CONVECTION INTO THE WRN FORECAST AREA AROUND 12Z. HAVE SLOWLY
STEPPED UP THE RAIN CHANCES BASED ON THE LOW-LEVEL JET AND
MOISTURE TRANSPORT CONVERGENCE IN CONCERT WITH INCREASING CAPE AS
THAT MOIST AIR MASS BEGINS ITS INFLUENCE. CURRENTLY MUCAPES OF
AROUND 1000 J/KG ARE WEST OF THE MISS RIVER...BUT THIS IS LIKELY
TO INCREASE OVERNIGHT AND PROBABLY BE IN THE 1300 J/KG RANGE BY
DAWN.

THE MOISTURE SURGE AND TRANSPORT SHIFT NORTHWARD AND BEGIN WHAT
APPEARS TO BE A LONGER TERM FOCUS OF CONVERGENCE NORTHWEST OF THE
FORECAST AREA. THIS AFTERNOON IT APPEARS THE MODEL GUIDANCE IS
CONSISTENT IN A FAIRLY UNIFORM SOUTHEAST FLOW OVER THE FORECAST
AREA...WITH CONVERGENCE ACROSS NRN WI TO CENTRAL MN...ALONG THE
STATIONARY BOUNDARY. WITH VERY HIGH MOISTURE IN PLACE AND SOME
HEATING...WE WILL BUILD SOME HIGHER MLCAPES AROUND 1800 J/KG
QUICKLY /MAYBE 3000 J/KG SBCAPE/. THIS USING A 67F DEWPOINT.

THE WIND SHEAR OVER THE AREA HAS BEEN CONSISTENTLY FORECAST BELOW
SUPERCELL THRESHOLDS THIS AFTERNOON WITH MOST OF THE SHEAR A
MODERATE 30-35KTS FROM 0-3KM AND LITTLE INCREASE ABOVE. THIS WOULD
FAVOR COLD POOL SYSTEMS AND BOWING WIND SEGMENTS. THE 19.00Z NAM
IS A BIT OF AN OUTLIER SUGGESTING STRONGER WINDS ALOFT FURTHER
NORTH...IN THE SUPERCELL RANGE. HAVE STAYED THE COURSE WITH A
WEAKER GRADIENT ALOFT WITH THE LOW CENTER STILL FAR WEST. SO THE
THREATS CONTINUE TO BE DAMAGING WIND AND LARGE HAIL. FLASH
FLOODING COULD ALSO BE A PROBLEM...SEE HYDROLOGY SECTION. AN
ISOLATED TORNADO IS POSSIBLE TOO.

THE MAIN PROBLEM RIGHT NOW SEEMS TO BE THE LACK OF A GOOD TRIGGER
THIS AFTERNOON. THE BOUNDARY LAYER FLOW IS A UNIFORM SOUTHEAST AND
LITTLE CONVERGENCE IS SEEN IN THE AREA. THUS...ANY BOUNDARY THAT
DOES PRESENT ITSELF COULD TRIGGER INITIATION AS THERE WILL BE NO
CAP IN PLACE. WITH SUCH VIGOROUS CONVECTION IN KS/OK...UPSTREAM OF
THE AREA...WE COULD SEE A CONVECTIVE VORTICITY MAX APPEAR IN THE
FLOW AND POSSIBLY BECOME AN INITIATOR. THE HRRR AND HI RES NMM SEEM
TO BE HINTING AT THIS SOLUTION LATER AFTERNOON.

THIS EVENING...AS STRONG ENERGY ROTATES NORTHEAST...CURRENTLY IN
WEST TX...THE LOW-LEVEL JET IN THE 19.00Z NAM EXCITES AND A NICE
CONVERGENT LOW-LEVEL JET DEVELOPS CONVECTION OVER IOWA AND MOVES
IT NORTHWARD. THE 19.00Z GFS DOES NOT AGREE ON THIS WITH ITS FOCUS
NORTH AGAIN ON THE NWRN WI-CENTRAL MN BOUNDARY. BUT THE HI RES 00Z
RUNS...USING THE NAM AS INITIALIZATION AND BOUNDARY
CONDITIONS...BRING WIDESPREAD CONVECTION IN FROM IA. THERE IS
BETTER JET DYNAMICS AND TRANSPORT IN THE NAM..AND THIS SEEMS
REASONABLE...THUS..HAVE CONTINUED TO HIT THE EVENING
HARD...EVOLVING THE WEATHER NORTH BY MORNING. THE 19.00Z GEM AND ECMWF
AGREE WELL WITH THIS SCENARIO. SO...LOOKING FOR A WET OVERNIGHT.
THERE IS STILL INSTABILITY OVERNIGHT...2K MUCAPE...AND A BIT
BETTER SHEAR.

BOTTOM LINE IS THAT THE DAYTIME HOURS MAY BE PRETTY CLEAN BECAUSE
OF LACK OF A THUNDERSTORM TRIGGER. IF AN MCV FROM OK/KS CAN
DEVELOP TSRA AND THE TSRA CAN ROOT ITSELF IN THE BOUNDARY LAYER
OVER IA...OR SOME BOUNDARY EXISTS...CHANCES INCREASE FOR AFTERNOON
SEVERE WEATHER...AS THE AIR MASS WILL BE WEAKLY CAPPED. THIS
EVENING SEEMS TO PROMOTE INCREASING RAIN AND THUNDERSTORMS WITH
STILL SOME SEVERE POTENTIAL UNTIL THE CAPE IS USED UP...BUT NOT
QUITE AS WIDESPREAD AS AN AFTERNOON EVENT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 318 AM CDT SUN MAY 19 2013

AS THE LOW DRAWS CLOSER MONDAY...SHEAR INCREASES TO SUPERCELL
STRENGTH...BUT AGAIN IT MAY BE DIFFICULT TO IDENTIFY A TRIGGER
WITH LITTLE SURFACE BOUNDARY ACTION IN THE AREA. THE STATIONARY
BOUNDARY REMAINS TO THE NW WITH THE BEST CONVERGENCE. HOWEVER...WITH
THE SURFACE LOW EXPECTED TO BE NEAR KFSD...AND AMPLE MLCAPE AGAIN
NEAR 2000 J/KG...STORMS LOOK TO FORM TO THE WEST AND MOVE INTO THE
AREA TUESDAY EVENING. HOWEVER...THIS PATTERN IS SO UNCAPPED AND
UNSTABLE...WE FOUND IT HARD TO GET DETAILED ON TIMING ANYWHERE.
MONDAY STILL HAS THE POTENTIAL FOR SEVERE WEATHER...AND IT LOOKS
LIKE THE EVENING HOURS. WITH INCREASED WIND SHEAR...ROTATING
STORMS ARE POSSIBLE AND THUS LARGE HAIL AND WIND. AN ISOLATED
TORNADO CANNOT BE RULED OUT BUT THE WIND ENVIRONMENT DOESNT LOOK
OVERLY FAVORABLE.

THE LOW CONTINUES TO SHIFT SLOWLY EAST AND PROVIDE RAIN THREATS
THAT ARE DIFFICULT TO TARGET THROUGH THURSDAY. SOME DRIER AIR BEGINS TO
SHIFT INTO THE AREA ON SOUTHWEST FLOW OFF THE ROCKIES ON
TUESDAY...AND SOMEWHAT COOLER AIR. THIS WILL END THE SEVERE
WEATHER THREAT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1245 AM CDT SUN MAY 19 2013

CONFIDENCE IS INCREASING THAT WEATHER WILL BE AROUND THE TAF SITES
IN THE MORNING HOURS AROUND 12Z. EXACTLY HOW THAT WILL AFFECT THE
AIRFIELDS IS STILL OF LOWER CONFIDENCE. WITH INCREASING
INSTABILITY MOVING IN AND SOME WEAK LIFT...THE CURRENT TSRA OVER
WRN IA WILL SHIFT INTO THE AREA AND WEAKEN AS IT MOVES TOWARD KLSE.
THUS...KRST HAS A BETTER CHANCE OF SEEING TSRA AT THE AIRFIELD
THAN KLSE.

THIS WILL BE A QUICK PERIOD OF WEATHER AND THEN A BREAK IS GOING
TO OCCUR UNTIL PROBABLY THE LATER AFTERNOON HOWEVER...THE TIMING
AND EXTENT OF THE WEATHER THIS AFTERNOON IS STILL VERY MUCH A
CHANGING FORECAST. IT APPEARS THE EVENING WILL BE OF GREATER
COVERAGE OF TSRA AND SHRA BUT THIS COULD BEGIN IN THE AFTERNOON.
PLENTY OF INSTABILITY IS IN PLACE....HIGHEST OF THE SEASON...BUT
THE EXACT TRIGGER FOR TSRA DEVELOPMENT IS IN QUESTION. SEVERE
WEATHER IS POSSIBLE WITH THE INSTABILITY IN PLACE AND LIFT
INCREASING THIS EVENING.


&&

.HYDROLOGY...
ISSUED AT 318 AM CDT SUN MAY 19 2013

HYDROLOGY...THE PROBABILITIES HAVE TIPPED TOWARD A FLASH FLOOD WATCH
FOR 3 PM TOPDAY THROUGH MONDAY. THERE ARE TOO MANY VARIABLES IN
PLAY THAT SUGGEST HEAVY RAINFALL AND FLOODING POTENTIAL INCLUDING
SOIL MOISTURE CENTERED OVER SERN MN ABNORMALLY HIGH...FRIDAYS
RAINFALL HAVING HIGHER END FLOODING OUTCOMES IN SERN
MN...PRECIPITABLE WATER VALUES OVER 150 PERCENT NORMAL MOVING
IN...SBCAPE BUILDING DURING THE DAY TO NEAR 3K /ML NEAR 1800/
BASED ON 67F DEW POINT...AND FORCING INCREASING DURING THE EVENING WITH
STRONGER MOISTURE TRANSPORT CONVERGENCE AND SHEAR MOVING INTO THE
AREA.

THIS FLASH FLOOD WATCH MAY BE EXPANDED AND POSSIBLY EXTENDED INTO
MONDAY NIGHT SHOULD DETAILS SUGGEST THE FLOODING THREAT COULD
REMAIN. THERE IS SOME SUGGESTION THAT THE VERY HIGH PRECIPITABLE
WATER MOIST CONVEYOR BELT WOULD SHIFT INTO WI AS A DRIER ROCKIES AIR
MASS ADVECTS IN ON SWRLY FLOW.

RIVERS IN THE WATCH AREA WOULD ALSO SEE RAPID RISES ASIDE FROM THE
FLASH FLOODING EFFECTS.

&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH FROM 3 PM CDT THIS AFTERNOON THROUGH MONDAY
     EVENING FOR MNZ079-086-087-094-095.

IA...FLASH FLOOD WATCH FROM 3 PM CDT THIS AFTERNOON THROUGH MONDAY
     EVENING FOR IAZ008.

&&&&

$$

SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...BAUMGARDT
HYDROLOGY...BAUMGARDT

000
FXUS63 KARX 190545
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1245 AM CDT SUN MAY 19 2013

.UPDATE...
ISSUED AT 724 PM CDT SAT MAY 18 2013

HAVE BEEN WORKING TO GET A BETTER HANDLE ON THE THUNDERSTORM
CHANCES AROUND DAYBREAK MOVING IN FROM THE SOUTHWEST. THE
THUNDERSTORM CHANCES ARE CLOSELY TIED TO THE SHORTWAVE TROUGH
SHIFTING OUT OF KS/OK AND THE FOCUS OF CURRENT DEEP CONVECTION
THERE. THE STORMS/SHRAS WOULD BE ON THE LEADING EDGE OF A MOISTURE
SURGE OF 12G/KG MIXING RATIO ABOVE THE SURFACE ON THE 305K SURFACE
/850MB/...THUS CAPE WILL INCREASE TOO...PER 18.23Z RAP. SHOULD SEE
THE LINE OF CONVECTION ADVECT ACROSS IA ON THE NOSE OF THIS
MOISTURE AND LOW-LEVEL JET CONVERGENCE. HOWEVER...THE BEST
LOW-LEVEL JET CONVERGENCE IS FURTHER INTO IA AND IS WEAKER IN THE
LOCAL AREA PER THE RAP. PROBABLY WHY THE RAP HAS THE AREA DRY.

THE SPC SSEO HAS A PROBABILITY OF 70+ PERCENT CHANCE OF 40DBZ OR
HIGHER FROM THE 7 CONVECTION ALLOWING MODELS BY 12Z ALONG I-35.
THIS IS PROBABILITY IS DECREASING HOWEVER. 3 OF THE LATEST 4 HRRR
RUNS ALSO HAVE A TSRA/SHRA ALONG I-35 BY 09Z IN MN-IA. THE LATEST
RUN 18.21Z BRINGS THIS CONVECTIVE SYSTEM TO JUST WEST OF THE MISS
RIVER BY 12Z SUN. THERE ARE CONVECTIVE ELEMENTS OVER 50 DBZ WITH
ABOUT 1200 J/KG OF MUCAPE WHICH IS ELEVATED. THE WIND SHEAR IS
FAIRLY WEAK WITH ONLY 20-30 KTS OF FLOW AT 6 KM.

HAVE UPDATED THE FORECAST TO INCLUDE A HIGHER CHANCE OF TSRA WEST
OF THE MISS RIVER SUNDAY AROUND DAYBREAK. THE FORCING IS WEAKER
THAN FURTHER TO THE SOUTHWEST /IA/...BUT THIS MOISTURE SURGE
ISENTROPICALLY LIFTING IN THE OVERNIGHT HOURS USUALLY PRODUCES
SOME ELEVATED STORMS. WILL CONTINUE TO MONITOR...RAIN CHANCES MAY
NEED TO BE INCREASED FURTHER. WITH LIMITED WIND SHEAR...WOULD
THINK POSSIBLY AN ISOLATED SEVERE HAILER MAY BE ABOUT ALL THAT COULD
OCCUR. THE RAINFALL SHOULD BE PROGRESSIVE...BUT ANY RAIN ON THE
SERN MN AREA HAS TO BE FOLLOWED CLOSELY...SOILS JUST CANNOT TAKE
IT. A FLASH FLOOD WATCH MAY BE NEEDED THERE. SEE FACEBOOK POST FOR
30 DAY WATER EQUIVALENT THAT HAS FALLEN THERE...5-8 INCHES ABOVE
NORMAL.

&&

.SHORT TERM...(TONIGHT AND SUNDAY)
ISSUED AT 250 PM CDT SUN MAY 18 2013

MORNING MCS QUICKLY DIED OUT FOR THE AFTERNOON...WHILE A SFC
WARM FRONT HANGS ACROSS CENTRAL MN INTO NORTHERN WI. THE 850 MB JET
KICKS IN ACROSS SOUTHERN/CENTRAL PLAINS...AND EXPECT SOME CONVECTION
TO INITIATE. STEERING WINDS WOULD FAVOR A NORTH/NORTHEAST
MOVEMENT...LIKELY KEEPING IT JUST WEST OF THE FORECAST AREA THROUGH
12Z. THAT SAID...MESO ARW/HRRR SUGGEST IT COULD WORK INTO NORTHEAST
IA/SOUTHEAST MN BY 12Z. THINK THE POSITIONING OF THE VARIOUS WEATHER
ELEMENTS GIVES THIS SOLUTION SOME MERIT...AND WILL TREND SOME POPS
TOWARD THIS. ELSEWHERE...SOME INSTABILITY A LOFT PER BUFKIT
SOUNDINGS...BUT WITHOUT A KICKER TO TAP INTO IT...SHOULD BE A DRY
NIGHT.

FOR SUNDAY...UPPER LEVEL TROUGH HANGS WELL WEST WHILE ITS SFC LOW
WOBBLES OVER THE PLAIN STATES. THE SFC WARM FRONT STAYS NORTH WITH
THE COLD FRONT SOUTH OF THE SFC LOW...BUT SOME HINTS THAT ANOTHER
SFC BOUNDARY COULD EXTEND FROM THE LOW ACROSS EASTERN IOWA. THE LOW
LEVEL JET AND MOISTURE TRANSPORT FOCUS INTO EASTERN IA/EASTERN
MN/WESTERN WI BY 00Z MONDAY...PERSISTING THROUGH THE EVENING HOURS.
GFS/NAM SFC TDS PUSH UPPER 60S TO LOW 70S INTO THE FORECAST AREA BY
00Z MON...WHICH IS PROBABLY OVERDONE...ESP THE GFS. MID 60S SEEM
MORE REASONABLE...SO ASSOCIATED MODELED SBCAPE VALUES WILL ALSO BE
LESS AS A RESULT. MLCAPES AROUND 1200 J/KG LOOK GOOD. 0-6 KM SHEAR
IS NOT THAT IMPRESSIVE...MOSTLY 30 KTS. LOW LEVEL SHEAR IS MUCH
BETTER...30+ KTS IN THE 0-3 KM LAYER...WITH 15-25 KTS OF 0-1KM SHEAR
FROM 00-06Z SUNDAY EVENING. THE ATMOSPHERE WOULD BE SUPPORTIVE OF
SEVERE WEATHER...WITH A BETTER CHANCE FOR SUPERCELL DEVELOPMENT
SOUTHWEST...WHICH COULD MIGRATE INTO THE FORECAST AREA.
OVERALL...THINK THE THREATS WOULD FOCUS ON LARGE HAIL...DAMAGING
WINDS...AND FLASH FLOODING. CAN/T RULE OUT AN ISOLATED TORNADO WITH
THE STRONG NEAR SFC SHEAR AND POTENTIAL FOR ANY SMALLER SFC BOUNDARY
PROVIDING ENHANCED VORTICITY.

TIMING...LOCATION...AND INITIATION ARE ALL RATHER NEBULOUS
THOUGH...AND CONFIDENCE IS LOW IN THE WHERES AND WHENS OF THE
CONVECTION. IT IS HIGHER THAT THE BEST PCPN CHANCES WILL BE SUNDAY
NIGHT...WITH THE MAIN SEVERE THREAT IN THE EVENING.

SCENARIO COULD PLAY OUT LIKE THIS...MCSS OVER THE PLAINS TONIGHT
MAKE THEIR WAY TOWARD THE FORECAST AREA SUNDAY MORNING. THEY MAY OR
MAY NOT BRING RAIN TO WESTERN PORTIONS OF THE AREA...BUT WILL AT
LEAST BRING SOME CLOUDS FOR THE EARLY PART OF THE DAY. ATMOSPHERE
WILL NEED SOME TIME TO CLEAR/THIN CLOUDS...SO INSTABILITY WILL BE
BUILD LATER IN THE DAY. THIS WILL THEN INTERACT WITH SFC BOUNDARY
HANGING SOUTHEAST FROM THE SFC LOW AND AN UPPER LEVEL SHORTWAVE
TROUGH ROTATING OUT OF THE MEAN TROUGH TO SPARK SHOWERS/STORMS OVER
IOWA. SUPERCELL DEVELOPMENT IS PROBABLE...WITH SHEAR SUGGESTING A
TRANSITION TO LINE/BOWING SEGMENTS AS THE STORMS MOVE INTO THE
AREA...DAMAGING WINDS POSSIBLE AS THE STORMS ORIENT TO THE 0-3KM
SHEAR VECTOR. AGAIN THOUGH...CAN/T RULE OUT ISOLATED TORNADOES AS
LOW LEVEL SHEAR AND VARIOUS/POSSIBLE SFC BOUNDARIES WOULD SUPPORT
THIS. OF COURSE...THESE SEVERE THREATS ARE CONDITIONAL ON HOW
QUICKLY THE ATMOSPHERE CAN RELOAD...AND WHERE THE VARIOUS BOUNDARIES
WILL LIE.

FORECAST NEEDS MORE CLARITY...WHICH HOPEFULLY COMES WHEN WE GET A
BETTER HANDLE ON WHAT THE OVERNIGHT CONVECTION WILL DO.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 250 PM CDT SAT MAY 18 2013

A WET START TO THE WORK WEEK AS THE UPPER LEVEL LOW WOBBLES VERY
SLOWLY EASTWARD...WITH VARIOUS BITS OF ENERGY ROTATING AROUND IT.
THE SFC LOW TAKE AN EASTWARD TRACK ACROSS NORTHERN IA. PERSISTENT
INFLUX OF LOW LEVEL MOISTURE AHEAD OF AND WRAPPED AROUND THE LOW.
THIS MIX WILL KEEP THE AREA UNDER PERIODS OF SHOWERS AND
THUNDERSTORM.

WITH INSTABILTY RE-ESTABLISHING ITSELF MONDAY
AFTERNOON/EVENING...AND DECENT WIND SHEAR...ANOTHER SHOT FOR SEVERE
WEATHER WILL BE POSSIBLE. MUCH WILL DEPEND ON WHERE VARIOUS MESO
FEATURES RESIDE...ALA SURFACES BOUNDARIES...AND WHERE THE GREATER
INSTABILITY BUILDS.

SOME HOPE THAT THE SLOW MOVING SYSTEM FINALLY EXITS EAST THU NIGHT
WITH THE EC MERGING THE UPPER LEVEL LOW WITH A DEEPER/STRONGER LOW
OVER THE NEW ENGLAND STATES. THE GFS...HOWEVER...LINGERS THE LOW
LONGER...AND WOULD FIRE A FEW MORE SHOWERS/STORMS AROUND THE LOW/SFC
BOUNDARY THU NIGHT INTO EARLY FRI. HIGH PRESSURE TAKES OVER FOR
FRI/FRI NIGHT...PROMISING A DRY PERIOD. THAT SAID...THE EC IS
ALREADY BRINGING IN SOME QPF TO THE WEST SAT WITH WARM AIR
ADVECTION/SHORTWAVE INTERACTION ON THE BACKSIDE OF THE HIGH.

NOT MUCH CONFIDENCE WITH WHEN THE LOW WILL FINALLY EXIT EAST...AND
MODEL DIFFERENCES AREN/T HELPING WITH THE CLARITY. WILL HOLD WITH
THE CONSENSUS SOLUTION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1245 AM CDT SUN MAY 19 2013

CONFIDENCE IS INCREASING THAT WEATHER WILL BE AROUND THE TAF SITES
IN THE MORNING HOURS AROUND 12Z. EXACTLY HOW THAT WILL AFFECT THE
AIRFIELDS IS STILL OF LOWER CONFIDENCE. WITH INCREASING
INSTABILITY MOVING IN AND SOME WEAK LIFT...THE CURRENT TSRA OVER
WRN IA WILL SHIFT INTO THE AREA AND WEAKEN AS IT MOVES TOWARD KLSE.
THUS...KRST HAS A BETTER CHANCE OF SEEING TSRA AT THE AIRFIELD
THAN KLSE.

THIS WILL BE A QUICK PERIOD OF WEATHER AND THEN A BREAK IS GOING
TO OCCUR UNTIL PROBABLY THE LATER AFTERNOON HOWEVER...THE TIMING
AND EXTENT OF THE WEATHER THIS AFTERNOON IS STILL VERY MUCH A
CHANGING FORECAST. IT APPEARS THE EVENING WILL BE OF GREATER
COVERAGE OF TSRA AND SHRA BUT THIS COULD BEGIN IN THE AFTERNOON.
PLENTY OF INSTABILITY IS IN PLACE....HIGHEST OF THE SEASON...BUT
THE EXACT TRIGGER FOR TSRA DEVELOPMENT IS IN QUESTION. SEVERE
WEATHER IS POSSIBLE WITH THE INSTABILITY IN PLACE AND LIFT
INCREASING THIS EVENING.

&&

.HYDROLOGY...SUNDAY AND INTO NEXT WEEK
ISSUED AT 250 PM CDT SAT MAY 18 2013

WITH CONSIDERABLE RAINFALL ACROSS PORTIONS OF SOUTHEAST MN AND
NORTHEAST IA YESTERDAY...SOILS ARE MOIST. 1 HR FFG IS FROM 1 1/2 TO
2 INCHES TO NEAR 2 INCHES FOR 3 HOURS. WHILE TODAY BROUGHT A PERIOD
OF DRYING...SHOWERS AND THUNDERSTORMS RETURN FOR SUNDAY INTO
WEDNESDAY. THERE IS THE POTENTIAL FOR 1 TO 3 INCHES OVER THIS
PERIOD. IF THIS FALLS IN A SHORT PERIOD...LOCALIZED FLASH FLOODING
WOULD OCCUR. A FLASH FLOOD WATCH MAY BE NECESSARY FOR PORTIONS OF
THE AREA. STREAMS...CREEKS...AND RIVERS HAVE RESPONDED TO THE RECENT
RAINFALL...MOSTLY WITHIN BANK RISES. HOWEVER...REPEATED ROUNDS OF
HEAVY RAIN COULD PUSH SOME OF THE MORE FLASHY BASINS ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA TO NEAR FLOOD STAGE.

&&

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

$$

UPDATE...BAUMGARDT
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...BAUMGARDT
HYDROLOGY....RIECK

000
FXUS63 KARX 190024
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
724 PM CDT SAT MAY 18 2013

.UPDATE...
ISSUED AT 724 PM CDT SAT MAY 18 2013

HAVE BEEN WORKING TO GET A BETTER HANDLE ON THE THUNDERSTORM
CHANCES AROUND DAYBREAK MOVING IN FROM THE SOUTHWEST. THE
THUNDERSTORM CHANCES ARE CLOSELY TIED TO THE SHORTWAVE TROUGH
SHIFTING OUT OF KS/OK AND THE FOCUS OF CURRENT DEEP CONVECTION
THERE. THE STORMS/SHRAS WOULD BE ON THE LEADING EDGE OF A MOISTURE
SURGE OF 12G/KG MIXING RATIO ABOVE THE SURFACE ON THE 305K SURFACE
/850MB/...THUS CAPE WILL INCREASE TOO...PER 18.23Z RAP. SHOULD SEE
THE LINE OF CONVECTION ADVECT ACROSS IA ON THE NOSE OF THIS
MOISTURE AND LOW-LEVEL JET CONVERGENCE. HOWEVER...THE BEST
LOW-LEVEL JET CONVERGENCE IS FURTHER INTO IA AND IS WEAKER IN THE
LOCAL AREA PER THE RAP. PROBABLY WHY THE RAP HAS THE AREA DRY.

THE SPC SSEO HAS A PROBABILITY OF 70+ PERCENT CHANCE OF 40DBZ OR
HIGHER FROM THE 7 CONVECTION ALLOWING MODELS BY 12Z ALONG I-35.
THIS IS PROBABILITY IS DECREASING HOWEVER. 3 OF THE LATEST 4 HRRR
RUNS ALSO HAVE A TSRA/SHRA ALONG I-35 BY 09Z IN MN-IA. THE LATEST
RUN 18.21Z BRINGS THIS CONVECTIVE SYSTEM TO JUST WEST OF THE MISS
RIVER BY 12Z SUN. THERE ARE CONVECTIVE ELEMENTS OVER 50 DBZ WITH
ABOUT 1200 J/KG OF MUCAPE WHICH IS ELEVATED. THE WIND SHEAR IS
FAIRLY WEAK WITH ONLY 20-30 KTS OF FLOW AT 6 KM.

HAVE UPDATED THE FORECAST TO INCLUDE A HIGHER CHANCE OF TSRA WEST
OF THE MISS RIVER SUNDAY AROUND DAYBREAK. THE FORCING IS WEAKER
THAN FURTHER TO THE SOUTHWEST /IA/...BUT THIS MOISTURE SURGE
ISENTROPICALLY LIFTING IN THE OVERNIGHT HOURS USUALLY PRODUCES
SOME ELEVATED STORMS. WILL CONTINUE TO MONITOR...RAIN CHANCES MAY
NEED TO BE INCREASED FURTHER. WITH LIMITED WIND SHEAR...WOULD
THINK POSSIBLY AN ISOLATED SEVERE HAILER MAY BE ABOUT ALL THAT COULD
OCCUR. THE RAINFALL SHOULD BE PROGRESSIVE...BUT ANY RAIN ON THE
SERN MN AREA HAS TO BE FOLLOWED CLOSELY...SOILS JUST CANNOT TAKE
IT. A FLASH FLOOD WATCH MAY BE NEEDED THERE. SEE FACEBOOK POST FOR
30 DAY WATER EQUIVALENT THAT HAS FALLEN THERE...5-8 INCHES ABOVE
NORMAL.

&&

.SHORT TERM...(TONIGHT AND SUNDAY)
ISSUED AT 250 PM CDT SUN MAY 18 2013

MORNING MCS QUICKLY DIED OUT FOR THE AFTERNOON...WHILE A SFC
WARM FRONT HANGS ACROSS CENTRAL MN INTO NORTHERN WI. THE 850 MB JET
KICKS IN ACROSS SOUTHERN/CENTRAL PLAINS...AND EXPECT SOME CONVECTION
TO INITIATE. STEERING WINDS WOULD FAVOR A NORTH/NORTHEAST
MOVEMENT...LIKELY KEEPING IT JUST WEST OF THE FORECAST AREA THROUGH
12Z. THAT SAID...MESO ARW/HRRR SUGGEST IT COULD WORK INTO NORTHEAST
IA/SOUTHEAST MN BY 12Z. THINK THE POSITIONING OF THE VARIOUS WEATHER
ELEMENTS GIVES THIS SOLUTION SOME MERIT...AND WILL TREND SOME POPS
TOWARD THIS. ELSEWHERE...SOME INSTABILITY A LOFT PER BUFKIT
SOUNDINGS...BUT WITHOUT A KICKER TO TAP INTO IT...SHOULD BE A DRY
NIGHT.

FOR SUNDAY...UPPER LEVEL TROUGH HANGS WELL WEST WHILE ITS SFC LOW
WOBBLES OVER THE PLAIN STATES. THE SFC WARM FRONT STAYS NORTH WITH
THE COLD FRONT SOUTH OF THE SFC LOW...BUT SOME HINTS THAT ANOTHER
SFC BOUNDARY COULD EXTEND FROM THE LOW ACROSS EASTERN IOWA. THE LOW
LEVEL JET AND MOISTURE TRANSPORT FOCUS INTO EASTERN IA/EASTERN
MN/WESTERN WI BY 00Z MONDAY...PERSISTING THROUGH THE EVENING HOURS.
GFS/NAM SFC TDS PUSH UPPER 60S TO LOW 70S INTO THE FORECAST AREA BY
00Z MON...WHICH IS PROBABLY OVERDONE...ESP THE GFS. MID 60S SEEM
MORE REASONABLE...SO ASSOCIATED MODELED SBCAPE VALUES WILL ALSO BE
LESS AS A RESULT. MLCAPES AROUND 1200 J/KG LOOK GOOD. 0-6 KM SHEAR
IS NOT THAT IMPRESSIVE...MOSTLY 30 KTS. LOW LEVEL SHEAR IS MUCH
BETTER...30+ KTS IN THE 0-3 KM LAYER...WITH 15-25 KTS OF 0-1KM SHEAR
FROM 00-06Z SUNDAY EVENING. THE ATMOSPHERE WOULD BE SUPPORTIVE OF
SEVERE WEATHER...WITH A BETTER CHANCE FOR SUPERCELL DEVELOPMENT
SOUTHWEST...WHICH COULD MIGRATE INTO THE FORECAST AREA.
OVERALL...THINK THE THREATS WOULD FOCUS ON LARGE HAIL...DAMAGING
WINDS...AND FLASH FLOODING. CAN/T RULE OUT AN ISOLATED TORNADO WITH
THE STRONG NEAR SFC SHEAR AND POTENTIAL FOR ANY SMALLER SFC BOUNDARY
PROVIDING ENHANCED VORTICITY.

TIMING...LOCATION...AND INITIATION ARE ALL RATHER NEBULOUS
THOUGH...AND CONFIDENCE IS LOW IN THE WHERES AND WHENS OF THE
CONVECTION. IT IS HIGHER THAT THE BEST PCPN CHANCES WILL BE SUNDAY
NIGHT...WITH THE MAIN SEVERE THREAT IN THE EVENING.

SCENARIO COULD PLAY OUT LIKE THIS...MCSS OVER THE PLAINS TONIGHT
MAKE THEIR WAY TOWARD THE FORECAST AREA SUNDAY MORNING. THEY MAY OR
MAY NOT BRING RAIN TO WESTERN PORTIONS OF THE AREA...BUT WILL AT
LEAST BRING SOME CLOUDS FOR THE EARLY PART OF THE DAY. ATMOSPHERE
WILL NEED SOME TIME TO CLEAR/THIN CLOUDS...SO INSTABILITY WILL BE
BUILD LATER IN THE DAY. THIS WILL THEN INTERACT WITH SFC BOUNDARY
HANGING SOUTHEAST FROM THE SFC LOW AND AN UPPER LEVEL SHORTWAVE
TROUGH ROTATING OUT OF THE MEAN TROUGH TO SPARK SHOWERS/STORMS OVER
IOWA. SUPERCELL DEVELOPMENT IS PROBABLE...WITH SHEAR SUGGESTING A
TRANSITION TO LINE/BOWING SEGMENTS AS THE STORMS MOVE INTO THE
AREA...DAMAGING WINDS POSSIBLE AS THE STORMS ORIENT TO THE 0-3KM
SHEAR VECTOR. AGAIN THOUGH...CAN/T RULE OUT ISOLATED TORNADOES AS
LOW LEVEL SHEAR AND VARIOUS/POSSIBLE SFC BOUNDARIES WOULD SUPPORT
THIS. OF COURSE...THESE SEVERE THREATS ARE CONDITIONAL ON HOW
QUICKLY THE ATMOSPHERE CAN RELOAD...AND WHERE THE VARIOUS BOUNDARIES
WILL LIE.

FORECAST NEEDS MORE CLARITY...WHICH HOPEFULLY COMES WHEN WE GET A
BETTER HANDLE ON WHAT THE OVERNIGHT CONVECTION WILL DO.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 250 PM CDT SAT MAY 18 2013

A WET START TO THE WORK WEEK AS THE UPPER LEVEL LOW WOBBLES VERY
SLOWLY EASTWARD...WITH VARIOUS BITS OF ENERGY ROTATING AROUND IT.
THE SFC LOW TAKE AN EASTWARD TRACK ACROSS NORTHERN IA. PERSISTENT
INFLUX OF LOW LEVEL MOISTURE AHEAD OF AND WRAPPED AROUND THE LOW.
THIS MIX WILL KEEP THE AREA UNDER PERIODS OF SHOWERS AND
THUNDERSTORM.

WITH INSTABILTY RE-ESTABLISHING ITSELF MONDAY
AFTERNOON/EVENING...AND DECENT WIND SHEAR...ANOTHER SHOT FOR SEVERE
WEATHER WILL BE POSSIBLE. MUCH WILL DEPEND ON WHERE VARIOUS MESO
FEATURES RESIDE...ALA SURFACES BOUNDARIES...AND WHERE THE GREATER
INSTABILITY BUILDS.

SOME HOPE THAT THE SLOW MOVING SYSTEM FINALLY EXITS EAST THU NIGHT
WITH THE EC MERGING THE UPPER LEVEL LOW WITH A DEEPER/STRONGER LOW
OVER THE NEW ENGLAND STATES. THE GFS...HOWEVER...LINGERS THE LOW
LONGER...AND WOULD FIRE A FEW MORE SHOWERS/STORMS AROUND THE LOW/SFC
BOUNDARY THU NIGHT INTO EARLY FRI. HIGH PRESSURE TAKES OVER FOR
FRI/FRI NIGHT...PROMISING A DRY PERIOD. THAT SAID...THE EC IS
ALREADY BRINGING IN SOME QPF TO THE WEST SAT WITH WARM AIR
ADVECTION/SHORTWAVE INTERACTION ON THE BACKSIDE OF THE HIGH.

NOT MUCH CONFIDENCE WITH WHEN THE LOW WILL FINALLY EXIT EAST...AND
MODEL DIFFERENCES AREN/T HELPING WITH THE CLARITY. WILL HOLD WITH
THE CONSENSUS SOLUTION.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 724 PM CDT SAT MAY 18 2013

VFR CONDITIONS OVERNIGHT UNTIL A POSSIBLE LINE OF TSRA WILL AFFECT
THE TAFS FROM THE SOUTHWEST. SOME CAPE WILL BE AVAILABLE AS THIS
MOISTURE SURGE MOVES IN AND THUS HAVE INTRODUCED A VCTS INTO THE
TAF. THIS IS NOT A HIGH CONFIDENCE FORECAST BUT CONFIDENCE IS
INCREASING ON SOME WEATHER MOVING THROUGH AROUND DAYBREAK. IF THE
TSRA IN THE MORNING CONTINUES ON AN INCREASING TREND...WILL NEED
TO BRING IN SOME MVFR CONDITIONS WITH +RA. THE BETTER C HANCES FOR
TSRA ARE CLOSER TO KRST...THUS HAVE NOT INCLUDED TS AT KLSE IN
THE MORNING FORECAST.

THIS WEATHER WILL MOVE THROUGH IN THE MORNING AND A VFR IS EXPECTED
UNTIL AN AFTERNOON THREAT OF TSRA PRESENTS ITSELF. DETAILS ON
TIMING ARE OF LOW CONFIDENCE...AND MUCH WILL HINGE ON SURFACE
BOUDNARIES TO FORM THUNDERSTORMS. IT APPEARS THE EVENING PERIOD
AFTER THE TAF ENDING TIME WILL BE MORE WIDESPREAD TSRA. SEVERE
WEATHER IS ALSO POSSIBLE WITH DURING THE LATER AFTERNOON AND
EVENING PERIOD.

&&

.HYDROLOGY...SUNDAY AND INTO NEXT WEEK
ISSUED AT 250 PM CDT SAT MAY 18 2013

WITH CONSIDERABLE RAINFALL ACROSS PORTIONS OF SOUTHEAST MN AND
NORTHEAST IA YESTERDAY...SOILS ARE MOIST. 1 HR FFG IS FROM 1 1/2 TO
2 INCHES TO NEAR 2 INCHES FOR 3 HOURS. WHILE TODAY BROUGHT A PERIOD
OF DRYING...SHOWERS AND THUNDERSTORMS RETURN FOR SUNDAY INTO
WEDNESDAY. THERE IS THE POTENTIAL FOR 1 TO 3 INCHES OVER THIS
PERIOD. IF THIS FALLS IN A SHORT PERIOD...LOCALIZED FLASH FLOODING
WOULD OCCUR. A FLASH FLOOD WATCH MAY BE NECESSARY FOR PORTIONS OF
THE AREA. STREAMS...CREEKS...AND RIVERS HAVE RESPONDED TO THE RECENT
RAINFALL...MOSTLY WITHIN BANK RISES. HOWEVER...REPEATED ROUNDS OF
HEAVY RAIN COULD PUSH SOME OF THE MORE FLASHY BASINS ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA TO NEAR FLOOD STAGE.

&&

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

$$

UPDATE...BAUMGARDT
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...BAUMGARDT
HYDROLOGY....RIECK

000
FXUS63 KARX 181958
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
250 PM CDT SAT MAY 18 2013

.SHORT TERM...(TONIGHT AND SUNDAY)
ISSUED AT 250 PM CDT SUN MAY 18 2013

MORNING MCS QUICKLY DIED OUT FOR THE AFTERNOON...WHILE A SFC
WARM FRONT HANGS ACROSS CENTRAL MN INTO NORTHERN WI. THE 850 MB JET
KICKS IN ACROSS SOUTHERN/CENTRAL PLAINS...AND EXPECT SOME CONVECTION
TO INITIATE. STEERING WINDS WOULD FAVOR A NORTH/NORTHEAST
MOVEMENT...LIKELY KEEPING IT JUST WEST OF THE FORECAST AREA THROUGH
12Z. THAT SAID...MESO ARW/HRRR SUGGEST IT COULD WORK INTO NORTHEAST
IA/SOUTHEAST MN BY 12Z. THINK THE POSITIONING OF THE VARIOUS WEATHER
ELEMENTS GIVES THIS SOLUTION SOME MERIT...AND WILL TREND SOME POPS
TOWARD THIS. ELSEWHERE...SOME INSTABILITY A LOFT PER BUFKIT
SOUNDINGS...BUT WITHOUT A KICKER TO TAP INTO IT...SHOULD BE A DRY
NIGHT.

FOR SUNDAY...UPPER LEVEL TROUGH HANGS WELL WEST WHILE ITS SFC LOW
WOBBLES OVER THE PLAIN STATES. THE SFC WARM FRONT STAYS NORTH WITH
THE COLD FRONT SOUTH OF THE SFC LOW...BUT SOME HINTS THAT ANOTHER
SFC BOUNDARY COULD EXTEND FROM THE LOW ACROSS EASTERN IOWA. THE LOW
LEVEL JET AND MOISTURE TRANSPORT FOCUS INTO EASTERN IA/EASTERN
MN/WESTERN WI BY 00Z MONDAY...PERSISTING THROUGH THE EVENING HOURS.
GFS/NAM SFC TDS PUSH UPPER 60S TO LOW 70S INTO THE FORECAST AREA BY
00Z MON...WHICH IS PROBABLY OVERDONE...ESP THE GFS. MID 60S SEEM
MORE REASONABLE...SO ASSOCIATED MODELED SBCAPE VALUES WILL ALSO BE
LESS AS A RESULT. MLCAPES AROUND 1200 J/KG LOOK GOOD. 0-6 KM SHEAR
IS NOT THAT IMPRESSIVE...MOSTLY 30 KTS. LOW LEVEL SHEAR IS MUCH
BETTER...30+ KTS IN THE 0-3 KM LAYER...WITH 15-25 KTS OF 0-1KM SHEAR
FROM 00-06Z SUNDAY EVENING. THE ATMOSPHERE WOULD BE SUPPORTIVE OF
SEVERE WEATHER...WITH A BETTER CHANCE FOR SUPERCELL DEVELOPMENT
SOUTHWEST...WHICH COULD MIGRATE INTO THE FORECAST AREA.
OVERALL...THINK THE THREATS WOULD FOCUS ON LARGE HAIL...DAMAGING
WINDS...AND FLASH FLOODING. CAN/T RULE OUT AN ISOLATED TORNADO WITH
THE STRONG NEAR SFC SHEAR AND POTENTIAL FOR ANY SMALLER SFC BOUNDARY
PROVIDING ENHANCED VORTICITY.

TIMING...LOCATION...AND INITIATION ARE ALL RATHER NEBULOUS
THOUGH...AND CONFIDENCE IS LOW IN THE WHERES AND WHENS OF THE
CONVECTION. IT IS HIGHER THAT THE BEST PCPN CHANCES WILL BE SUNDAY
NIGHT...WITH THE MAIN SEVERE THREAT IN THE EVENING.

SCENARIO COULD PLAY OUT LIKE THIS...MCSS OVER THE PLAINS TONIGHT
MAKE THEIR WAY TOWARD THE FORECAST AREA SUNDAY MORNING. THEY MAY OR
MAY NOT BRING RAIN TO WESTERN PORTIONS OF THE AREA...BUT WILL AT
LEAST BRING SOME CLOUDS FOR THE EARLY PART OF THE DAY. ATMOSPHERE
WILL NEED SOME TIME TO CLEAR/THIN CLOUDS...SO INSTABILITY WILL BE
BUILD LATER IN THE DAY. THIS WILL THEN INTERACT WITH SFC BOUNDARY
HANGING SOUTHEAST FROM THE SFC LOW AND AN UPPER LEVEL SHORTWAVE
TROUGH ROTATING OUT OF THE MEAN TROUGH TO SPARK SHOWERS/STORMS OVER
IOWA. SUPERCELL DEVELOPMENT IS PROBABLE...WITH SHEAR SUGGESTING A
TRANSITION TO LINE/BOWING SEGMENTS AS THE STORMS MOVE INTO THE
AREA...DAMAGING WINDS POSSIBLE AS THE STORMS ORIENT TO THE 0-3KM
SHEAR VECTOR. AGAIN THOUGH...CAN/T RULE OUT ISOLATED TORNADOES AS
LOW LEVEL SHEAR AND VARIOUS/POSSIBLE SFC BOUNDARIES WOULD SUPPORT
THIS. OF COURSE...THESE SEVERE THREATS ARE CONDITIONAL ON HOW
QUICKLY THE ATMOSPHERE CAN RELOAD...AND WHERE THE VARIOUS BOUNDARIES
WILL LIE.

FORECAST NEEDS MORE CLARITY...WHICH HOPEFULLY COMES WHEN WE GET A
BETTER HANDLE ON WHAT THE OVERNIGHT CONVECTION WILL DO.


.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 250 PM CDT SAT MAY 18 2013

A WET START TO THE WORK WEEK AS THE UPPER LEVEL LOW WOBBLES VERY
SLOWLY EASTWARD...WITH VARIOUS BITS OF ENERGY ROTATING AROUND IT.
THE SFC LOW TAKE AN EASTWARD TRACK ACROSS NORTHERN IA. PERSISTENT
INFLUX OF LOW LEVEL MOISTURE AHEAD OF AND WRAPPED AROUND THE LOW.
THIS MIX WILL KEEP THE AREA UNDER PERIODS OF SHOWERS AND
THUNDERSTORM.

WITH INSTABILTY RE-ESTABLISHING ITSELF MONDAY
AFTERNOON/EVENING...AND DECENT WIND SHEAR...ANOTHER SHOT FOR SEVERE
WEATHER WILL BE POSSIBLE. MUCH WILL DEPEND ON WHERE VARIOUS MESO
FEATURES RESIDE...ALA SURFACES BOUNDARIES...AND WHERE THE GREATER
INSTABILITY BUILDS.

SOME HOPE THAT THE SLOW MOVING SYSTEM FINALLY EXITS EAST THU NIGHT
WITH THE EC MERGING THE UPPER LEVEL LOW WITH A DEEPER/STRONGER LOW
OVER THE NEW ENGLAND STATES. THE GFS...HOWEVER...LINGERS THE LOW
LONGER...AND WOULD FIRE A FEW MORE SHOWERS/STORMS AROUND THE LOW/SFC
BOUNDARY THU NIGHT INTO EARLY FRI. HIGH PRESSURE TAKES OVER FOR
FRI/FRI NIGHT...PROMISING A DRY PERIOD. THAT SAID...THE EC IS
ALREADY BRINGING IN SOME QPF TO THE WEST SAT WITH WARM AIR
ADVECTION/SHORTWAVE INTERACTION ON THE BACKSIDE OF THE HIGH.

NOT MUCH CONFIDENCE WITH WHEN THE LOW WILL FINALLY EXIT EAST...AND
MODEL DIFFERENCES AREN/T HELPING WITH THE CLARITY. WILL HOLD WITH
THE CONSENSUS SOLUTION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED
AT 1256 PM CDT SAT MAY 18 2013

A MOIST AIRMASS FLOWING INTO THE REGION THIS AFTERNOON WILL
PRODUCE SCATTERED TO BROKEN CUMULUS CLOUDS WITH BASES IN THE 2500
TO 3500 FT RANGE. SOUTH WINDS WILL INCREASE THIS AFTERNOON TO
AROUND 10 KTS AT KLSE AND TO AROUND 14 KTS AT KRST. CANNOT RULE
OUT AN ISOLATED SHOWER OR THUNDERSTORM THIS AFTERNOON...BUT THIS
LOOKS UNLIKELY GIVEN THE LACK OF FORCING. CHANCES FOR SHOWERS AND
STORMS INCREASE ACROSS THE REGION ON SUNDAY AS A LOW PRESSURE
SYSTEM DEEPENS OVER THE NORTHERN PLAINS. AT THIS TIME...THE
HIGHEST CHANCES FOR SHOWERS AND POSSIBLY A THUNDERSTORM APPEARS TO
BE AT KRST IN THE 10 TO 14Z TIMEFRAME...THEN ACROSS MUCH OF THE
AREA LATE SUNDAY AFTERNOON INTO SUNDAY EVENING. THE STORMS COULD
PRODUCE PERIODS OF HEAVY RAIN...GUSTY WINDS AND HAIL...ESPECIALLY
DURING THE LATE AFTERNOON AND EVENING ON SUNDAY.

&&

.HYDROLOGY...SUNDAY AND INTO NEXT WEEK
ISSUED AT 250 PM CDT SAT MAY 18 2013

WITH CONSIDERABLE RAINFALL ACROSS PORTIONS OF SOUTHEAST MN AND
NORTHEAST IA YESTERDAY...SOILS ARE MOIST. 1 HR FFG IS FROM 1 1/2 TO
2 INCHES TO NEAR 2 INCHES FOR 3 HOURS. WHILE TODAY BROUGHT A PERIOD
OF DRYING...SHOWERS AND THUNDERSTORMS RETURN FOR SUNDAY INTO
WEDNESDAY. THERE IS THE POTENTIAL FOR 1 TO 3 INCHES OVER THIS
PERIOD. IF THIS FALLS IN A SHORT PERIOD...LOCALIZED FLASH FLOODING
WOULD OCCUR. A FLASH FLOOD WATCH MAY BE NECESSARY FOR PORTIONS OF
THE AREA. STREAMS...CREEKS...AND RIVERS HAVE RESPONDED TO THE RECENT
RAINFALL...MOSTLY WITHIN BANK RISES. HOWEVER...REPEATED ROUNDS OF
HEAVY RAIN COULD PUSH SOME OF THE MORE FLASHY BASINS ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA TO NEAR FLOOD STAGE.

&&

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

$$

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

000
FXUS63 KARX 181756
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1256 PM CDT SAT MAY 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT MAY 18 2013

UPPER LEVEL RIDGING TAKING PLACE ACROSS THE UPPER MIDWEST TODAY AS
THE WESTERN CONUS TROUGH DEEPENS. PLENTY OF CONVECTION FIRING UP OFF
THE 850 MB LLJ IN CONJUNCTION WITH A PASSING SHORTWAVE ACROSS
CENTRAL MINNESOTA BACK INTO THE DAKOTAS. THIS ACTIVITY WILL MOSTLY
REMAIN NORTH/NORTHWEST OF THE FORECAST AREA...HOWEVER COULD CLIP
PORTIONS OF NORTH CENTRAL WISCONSIN BY MID TO LATE MORNING. LATEST
RUNS OF THE HRRR AND RAP SHOW CONVECTION WANING BUT POSSIBLY
IMPACTING TAYLOR AND CLARK COUNTIES IN WISCONSIN SO HAVE MAINTAINED
SHOWER/STORM CHANCES THERE. MOIST EASTERLY FLOW AND DECAYING
CIRRUS WILL KEEP SKIES MOSTLY CLOUDY TO OVERCAST THIS
MORNING...BUT AS THE MCS LIFTS NORTH...IT WILL PULL THE WARM FRONT
THROUGH THE AREA. PARTLY TO MOSTLY SUNNY SKIES WILL MOST LIKELY BE
SEEN ACROSS NORTHEAST IOWA WHERE THE FRONT IS ABLE TO CLEAR
THROUGH THE MOST.

DECENT INSTABILITY EXPECTED TODAY IN THE WARM SECTOR...AND MUCAPE
VALUES RANGE FROM 1000 TO 2000 J/KG IN A WEAKLY CAPPED ENVIRONMENT.
LACK OF SURFACE CONVERGENCE HOWEVER PRECLUDES HIGHER PRECIPITATION
CHANCES BUT MOST OF THE DETERMINISTIC AND PROBABILISTIC GUIDANCE
HINTS THAT CENTRAL WISCONSIN COULD SEE A STRAY SHOWER OR
THUNDERSTORM THIS AFTERNOON. HAVE MAINTAINED PRECIPITATION CHANCES
THERE. OTHERWISE...A WARM DAY ON TAP WITH LOWER TO MID 80S EXPECTED
SOUTH OF I-94.

RELATIVELY QUIET CONDITIONS TONIGHT AS CONVECTION IS EXPECTED TO
REMAIN WELL TO THE WEST AND NORTH. MILD NIGHT WITH SOUTHERLY
FLOW...AND OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT MAY 18 2013

FOCUS IS ON SEVERE WEATHER CHANCES SUNDAY AND MONDAY AS ACTIVE
WEATHER PATTERN SETS UP ACROSS MUCH OF THE CENTRAL PLAINS.

UPPER LEVEL NEGATIVE TILTED SHORTWAVE TROUGH EJECTS INTO THE CENTRAL
PLAINS ON SUNDAY...MEANWHILE AT THE SURFACE A FEW WAVES OF LOW PRESSURE
SHOULD BE DEVELOPING ACROSS OKLAHOMA INTO NEBRASKA. THIS WILL PULL
NORTH AMPLE GULF OF MEXICO MOISTURE...WITH PWATS INCREASING FROM
AROUND 1 INCH...TO NEARLY 1.75 INCHES...OR 175 PERCENT OF NORMAL.
SURFACE DEWPOINTS WILL RISE INTO THE LOW TO MIDDLE 60S. THERE SHOULD
BE CONVECTION ACROSS WESTERN IOWA INTO SOUTHWEST MINNESOTA EARLY
SUNDAY MORNING...WHICH WILL BE FEEDING OFF THE 850 MB LLJ. THIS
SHOULD WEAKEN AS IT APPROACHES THE WESTERN FORECAST AREA BUT GOOD
CONSENSUS THAT SHOWERS AND THUNDERSTORMS WILL BE AROUND IN THE
MORNING HOURS. THEN...THE BIG QUESTION BECOMES HOW MUCH CLEARING
WE WOULD SEE TO AID IN DESTABILIZATION. ASSUMING WE CLEAR
OUT...0-3KM MUCAPE IS EXPECTED TO INCREASE TO 1500-2000
J/KG...HIGHEST TO THE SOUTH AND WEST. OVERALL THE SHEAR PROFILES
ARE LESS IMPRESSIVE...BUT STILL SHOW 0-3KM BULK SHEAR OF NEARLY 30
KTS. THE ATMOSPHERE DOES REMAIN UNCAPPED SO EXPECTING GOOD CHANCES
OF CONVECTIVE INITIATION WITH ORGANIZED STORMS IN THE FORM OF
SUPERCELLS OR POSSIBLY BOWING SEGMENTS. STRONG TO SEVERE STORMS
WOULD DEVELOP ACROSS WESTERN INTO CENTRAL IOWA...AND TRACK
EAST/NORTHEAST THROUGH THE EVENING HOURS. THE PRIMARY THREATS ARE
LARGE HAIL AND DAMAGING WINDS. THE ENVIRONMENT STILL SUPPORTS AN
ISOLATED TORNADO...HOWEVER DEPENDING WHERE A WARM FRONT LAYS IS
MORE UNCERTAIN. 18.00Z GFS HAS THIS BOUNDARY ACROSS CENTRAL
IOWA...BUT 18.00Z ECMWF/NAM HINT THIS COULD BE FURTHER SOUTH.

THE WHOLE SYSTEM EDGES EASTWARD MONDAY...WITH THE BOTH THE
SURFACE AND UPPER LEVEL LOW BECOMING STACKED NEAR SIOUX FALLS SD
BY 12Z MONDAY. PIECES OF ENERGY WILL BE ROTATING THROUGH SOUTHERN
BEND OF THIS TROUGH...LIFTING THROUGH THE AREA DURING THE DAY. THE
SYNOPTIC SETUP IS SLIGHTLY MORE FAVORABLE FOR SEVERE WEATHER FOR
PARTS OF THE AREA. THE SHEAR PROFILES ARE MORE IMPRESSIVE WITH
0-6KM BULK SHEAR VALUES 40 TO 50 KTS ACROSS EASTERN IOWA INTO
SOUTHERN WISCONSIN. THE MORE LIMITING FACTOR THIS DAY IS HOW MUCH
DESTABILIZATION WILL OCCUR. THERE COULD BE SCATTERED SHOWERS AND
PLENTY OF CLOUDS AROUND TO LIMIT INSTABILITY. IF WE CAN BREAK OUT
AND FULLY DESTABILIZE...THEN 0-3KM MUCAPE MAY REACH 1500 TO 2000
J/KG. THE ENVIRONMENT SHOULD SUPPORT DISCRETE STORM CELLS...WITH
THE THREATS AGAIN LARGE HAIL AND DAMAGING WINDS.

TUESDAY AND BEYOND...THE UPPER LOW REMAINS NEARLY STATIONARY ACROSS
THE UPPER MIDWEST. THIS GIVES PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS THE ENTIRE AREA TUESDAY-THURSDAY. MODEL
CONSENSUS PAINTS 30 TO 60 PERCENT CHANCES WHICH IS APPROPRIATE AT
THIS TIME. FEEL THAT MUCH OF NEXT WEEK COULD BE UNSETTLED BUT SEE
LITTLE OPPORTUNITY TO PROVIDE MORE DETAILS IN WHAT PERIODS WOULD BE
MORE ACTIVE...SINCE TIMING PIECES OF ROTATING AROUND THE UPPER LOW
IS DIFFICULT THIS FAR OUT. THE BIGGER STORY WOULD BE THE HEIGHTENED
RISK FOR EXCESSIVE RAINFALL AND LOCALIZED FLOODING IF REPEATED
ROUNDS OF CONVECTION DO IMPACT THE AREA. BY MID-WEEK...SOILS WOULD
BECOME EVEN MORE SATURATED...AND FLASH GUIDANCE FURTHER REDUCED. SEE
HYDROLOGY SECTION BELOW FOR MORE DETAILS ON THAT RISK.

TEMPERATURE-WISE...WARMEST DAYS LOOK TO BE SUNDAY AND MONDAY BEFORE
A GRADUAL COOL DOWN TUESDAY...THEN TO BELOW NORMAL READINGS
WEDNESDAY THROUGH THURSDAY AS THE UPPER LOW DRIFTS OVERHEAD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1256 PM CDT SAT MAY 18 2013

A MOIST AIRMASS FLOWING INTO THE REGION THIS AFTERNOON WILL
PRODUCE SCATTERED TO BROKEN CUMULUS CLOUDS WITH BASES IN THE 2500
TO 3500 FT RANGE. SOUTH WINDS WILL INCREASE THIS AFTERNOON TO
AROUND 10 KTS AT KLSE AND TO AROUND 14 KTS AT KRST. CANNOT RULE
OUT AN ISOLATED SHOWER OR THUNDERSTORM THIS AFTERNOON...BUT THIS
LOOKS UNLIKELY GIVEN THE LACK OF FORCING. CHANCES FOR SHOWERS AND
STORMS INCREASE ACROSS THE REGION ON SUNDAY AS A LOW PRESSURE
SYSTEM DEEPENS OVER THE NORTHERN PLAINS. AT THIS TIME...THE
HIGHEST CHANCES FOR SHOWERS AND POSSIBLY A THUNDERSTORM APPEARS TO
BE AT KRST IN THE 10 TO 14Z TIMEFRAME...THEN ACROSS MUCH OF THE
AREA LATE SUNDAY AFTERNOON INTO SUNDAY EVENING. THE STORMS COULD
PRODUCE PERIODS OF HEAVY RAIN...GUSTY WINDS AND HAIL...ESPECIALLY
DURING THE LATE AFTERNOON AND EVENING ON SUNDAY.

&&

.HYDROLOGY...SUNDAY AND INTO NEXT WEEK
ISSUED AT 400 AM CDT SAT MAY 18 2013

HEAVY RAINFALL /2 TO 2.5 INCHES/ FELL FRIDAY ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA...AND COMBINED WITH A RECORD
WET METEOROLOGICAL SPRING...RESULTS IN AN INCREASED RISK FOR
LOCALIZED FLASH FLOODING AS WE HEAD INTO THE LATTER PART OF THE
WEEKEND AND MUCH OF NEXT WEEK. PERIODS OF SHOWERS AND THUNDERSTORMS
LOOK TO IMPACT MUCH OF SOUTHEAST MINNESOTA AND NORTHEAST BEGINNING
SUNDAY AFTERNOON. AN ADDITIONAL 1 TO 3 INCHES IS POSSIBLE...AND IF
THIS FALLS IN A SHORT PERIOD...LOCALIZED FLASH FLOODING WOULD OCCUR.
THE 1 AND 3 HOUR FLASH GUIDANCE REMAINS WELL BELOW NORMAL...AND IS
GENERALLY LESS THAN 1 AND 2 INCHES...RESPECTIVELY. WPC CONTINUES THE
SLIGHT RISK OF EXCESSIVE RAINFALL AND FLASH FLOODING EARLY NEXT WEEK
ACROSS MUCH OF CENTRAL MINNESOTA INTO NORTHWEST WISCONSIN. A FLASH
FLOOD WATCH MAY BE NECESSARY FOR PORTIONS OF THE AREA.
STREAMS...CREEKS...AND RIVERS HAVE RESPONDED TO THE RECENT
RAINFALL...MOSTLY WITHIN BANK RISES. HOWEVER...REPEATED ROUNDS OF
HEAVY RAIN COULD PUSH SOME OF THE MORE FLASHY BASINS ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA TO NEAR FLOOD STAGE.

&&

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

$$

SHORT TERM...ZT
LONG TERM...ZT
AVIATION...WETENKAMP
HYDROLOGY...ZT

000
FXUS63 KARX 181145
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
645 AM CDT SAT MAY 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT MAY 18 2013

UPPER LEVEL RIDGING TAKING PLACE ACROSS THE UPPER MIDWEST TODAY AS
THE WESTERN CONUS TROUGH DEEPENS. PLENTY OF CONVECTION FIRING UP OFF
THE 850 MB LLJ IN CONJUNCTION WITH A PASSING SHORTWAVE ACROSS
CENTRAL MINNESOTA BACK INTO THE DAKOTAS. THIS ACTIVITY WILL MOSTLY
REMAIN NORTH/NORTHWEST OF THE FORECAST AREA...HOWEVER COULD CLIP
PORTIONS OF NORTH CENTRAL WISCONSIN BY MID TO LATE MORNING. LATEST
RUNS OF THE HRRR AND RAP SHOW CONVECTION WANING BUT POSSIBLY
IMPACTING TAYLOR AND CLARK COUNTIES IN WISCONSIN SO HAVE MAINTAINED
SHOWER/STORM CHANCES THERE. MOIST EASTERLY FLOW AND DECAYING
CIRRUS WILL KEEP SKIES MOSTLY CLOUDY TO OVERCAST THIS
MORNING...BUT AS THE MCS LIFTS NORTH...IT WILL PULL THE WARM FRONT
THROUGH THE AREA. PARTLY TO MOSTLY SUNNY SKIES WILL MOST LIKELY BE
SEEN ACROSS NORTHEAST IOWA WHERE THE FRONT IS ABLE TO CLEAR
THROUGH THE MOST.

DECENT INSTABILITY EXPECTED TODAY IN THE WARM SECTOR...AND MUCAPE
VALUES RANGE FROM 1000 TO 2000 J/KG IN A WEAKLY CAPPED ENVIRONMENT.
LACK OF SURFACE CONVERGENCE HOWEVER PRECLUDES HIGHER PRECIPITATION
CHANCES BUT MOST OF THE DETERMINISTIC AND PROBABILISTIC GUIDANCE
HINTS THAT CENTRAL WISCONSIN COULD SEE A STRAY SHOWER OR
THUNDERSTORM THIS AFTERNOON. HAVE MAINTAINED PRECIPITATION CHANCES
THERE. OTHERWISE...A WARM DAY ON TAP WITH LOWER TO MID 80S EXPECTED
SOUTH OF I-94.

RELATIVELY QUIET CONDITIONS TONIGHT AS CONVECTION IS EXPECTED TO
REMAIN WELL TO THE WEST AND NORTH. MILD NIGHT WITH SOUTHERLY
FLOW...AND OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT MAY 18 2013

FOCUS IS ON SEVERE WEATHER CHANCES SUNDAY AND MONDAY AS ACTIVE
WEATHER PATTERN SETS UP ACROSS MUCH OF THE CENTRAL PLAINS.

UPPER LEVEL NEGATIVE TILTED SHORTWAVE TROUGH EJECTS INTO THE CENTRAL
PLAINS ON SUNDAY...MEANWHILE AT THE SURFACE A FEW WAVES OF LOW PRESSURE
SHOULD BE DEVELOPING ACROSS OKLAHOMA INTO NEBRASKA. THIS WILL PULL
NORTH AMPLE GULF OF MEXICO MOISTURE...WITH PWATS INCREASING FROM
AROUND 1 INCH...TO NEARLY 1.75 INCHES...OR 175 PERCENT OF NORMAL.
SURFACE DEWPOINTS WILL RISE INTO THE LOW TO MIDDLE 60S. THERE SHOULD
BE CONVECTION ACROSS WESTERN IOWA INTO SOUTHWEST MINNESOTA EARLY
SUNDAY MORNING...WHICH WILL BE FEEDING OFF THE 850 MB LLJ. THIS
SHOULD WEAKEN AS IT APPROACHES THE WESTERN FORECAST AREA BUT GOOD
CONSENSUS THAT SHOWERS AND THUNDERSTORMS WILL BE AROUND IN THE
MORNING HOURS. THEN...THE BIG QUESTION BECOMES HOW MUCH CLEARING
WE WOULD SEE TO AID IN DESTABILIZATION. ASSUMING WE CLEAR
OUT...0-3KM MUCAPE IS EXPECTED TO INCREASE TO 1500-2000
J/KG...HIGHEST TO THE SOUTH AND WEST. OVERALL THE SHEAR PROFILES
ARE LESS IMPRESSIVE...BUT STILL SHOW 0-3KM BULK SHEAR OF NEARLY 30
KTS. THE ATMOSPHERE DOES REMAIN UNCAPPED SO EXPECTING GOOD CHANCES
OF CONVECTIVE INITIATION WITH ORGANIZED STORMS IN THE FORM OF
SUPERCELLS OR POSSIBLY BOWING SEGMENTS. STRONG TO SEVERE STORMS
WOULD DEVELOP ACROSS WESTERN INTO CENTRAL IOWA...AND TRACK
EAST/NORTHEAST THROUGH THE EVENING HOURS. THE PRIMARY THREATS ARE
LARGE HAIL AND DAMAGING WINDS. THE ENVIRONMENT STILL SUPPORTS AN
ISOLATED TORNADO...HOWEVER DEPENDING WHERE A WARM FRONT LAYS IS
MORE UNCERTAIN. 18.00Z GFS HAS THIS BOUNDARY ACROSS CENTRAL
IOWA...BUT 18.00Z ECMWF/NAM HINT THIS COULD BE FURTHER SOUTH.

THE WHOLE SYSTEM EDGES EASTWARD MONDAY...WITH THE BOTH THE
SURFACE AND UPPER LEVEL LOW BECOMING STACKED NEAR SIOUX FALLS SD
BY 12Z MONDAY. PIECES OF ENERGY WILL BE ROTATING THROUGH SOUTHERN
BEND OF THIS TROUGH...LIFTING THROUGH THE AREA DURING THE DAY. THE
SYNOPTIC SETUP IS SLIGHTLY MORE FAVORABLE FOR SEVERE WEATHER FOR
PARTS OF THE AREA. THE SHEAR PROFILES ARE MORE IMPRESSIVE WITH
0-6KM BULK SHEAR VALUES 40 TO 50 KTS ACROSS EASTERN IOWA INTO
SOUTHERN WISCONSIN. THE MORE LIMITING FACTOR THIS DAY IS HOW MUCH
DESTABILIZATION WILL OCCUR. THERE COULD BE SCATTERED SHOWERS AND
PLENTY OF CLOUDS AROUND TO LIMIT INSTABILITY. IF WE CAN BREAK OUT
AND FULLY DESTABILIZE...THEN 0-3KM MUCAPE MAY REACH 1500 TO 2000
J/KG. THE ENVIRONMENT SHOULD SUPPORT DISCRETE STORM CELLS...WITH
THE THREATS AGAIN LARGE HAIL AND DAMAGING WINDS.

TUESDAY AND BEYOND...THE UPPER LOW REMAINS NEARLY STATIONARY ACROSS
THE UPPER MIDWEST. THIS GIVES PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS THE ENTIRE AREA TUESDAY-THURSDAY. MODEL
CONSENSUS PAINTS 30 TO 60 PERCENT CHANCES WHICH IS APPROPRIATE AT
THIS TIME. FEEL THAT MUCH OF NEXT WEEK COULD BE UNSETTLED BUT SEE
LITTLE OPPORTUNITY TO PROVIDE MORE DETAILS IN WHAT PERIODS WOULD BE
MORE ACTIVE...SINCE TIMING PIECES OF ROTATING AROUND THE UPPER LOW
IS DIFFICULT THIS FAR OUT. THE BIGGER STORY WOULD BE THE HEIGHTENED
RISK FOR EXCESSIVE RAINFALL AND LOCALIZED FLOODING IF REPEATED
ROUNDS OF CONVECTION DO IMPACT THE AREA. BY MID-WEEK...SOILS WOULD
BECOME EVEN MORE SATURATED...AND FLASH GUIDANCE FURTHER REDUCED. SEE
HYDROLOGY SECTION BELOW FOR MORE DETAILS ON THAT RISK.

TEMPERATURE-WISE...WARMEST DAYS LOOK TO BE SUNDAY AND MONDAY BEFORE
A GRADUAL COOL DOWN TUESDAY...THEN TO BELOW NORMAL READINGS
WEDNESDAY THROUGH THURSDAY AS THE UPPER LOW DRIFTS OVERHEAD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 644 AM CDT SAT MAY 18 2013

WITH THE BEST FORCING REMAINING NORTH AND WEST OF THE FORECAST
AREA THROUGH THIS EVENING...KEPT THE TAF SITES DRY WITH CEILINGS
ABOVE 12K FEET. THE MESO MODELS ARE IN GOOD AGREEMENT THAT A SHORT
WAVE TROUGH WILL MOVE NORTHEAST THROUGH THE AREA. THIS WILL BRING
SHOWERS AND THUNDERSTORMS TO NORTHEAST IOWA AND SOUTHEAST
MINNESOTA AFTER 19.09Z. DESPITE THIS PRECIPITATION...SOUNDINGS
SUGGEST THAT THE CEILINGS WILL REMAIN VFR. WHILE THERE MAY BE
SOME BRIEF VISIBILITIES IN THE IFR/MVFR RANGE...TIMING IS VERY
UNCERTAIN...SO LEFT THEM VFR.

&&

.HYDROLOGY...SUNDAY AND INTO NEXT WEEK
ISSUED AT 400 AM CDT SAT MAY 18 2013

HEAVY RAINFALL /2 TO 2.5 INCHES/ FELL FRIDAY ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA...AND COMBINED WITH A RECORD
WET METEOROLOGICAL SPRING...RESULTS IN AN INCREASED RISK FOR
LOCALIZED FLASH FLOODING AS WE HEAD INTO THE LATTER PART OF THE
WEEKEND AND MUCH OF NEXT WEEK. PERIODS OF SHOWERS AND THUNDERSTORMS
LOOK TO IMPACT MUCH OF SOUTHEAST MINNESOTA AND NORTHEAST BEGINNING
SUNDAY AFTERNOON. AN ADDITIONAL 1 TO 3 INCHES IS POSSIBLE...AND IF
THIS FALLS IN A SHORT PERIOD...LOCALIZED FLASH FLOODING WOULD OCCUR.
THE 1 AND 3 HOUR FLASH GUIDANCE REMAINS WELL BELOW NORMAL...AND IS
GENERALLY LESS THAN 1 AND 2 INCHES...RESPECTIVELY. WPC CONTINUES THE
SLIGHT RISK OF EXCESSIVE RAINFALL AND FLASH FLOODING EARLY NEXT WEEK
ACROSS MUCH OF CENTRAL MINNESOTA INTO NORTHWEST WISCONSIN. A FLASH
FLOOD WATCH MAY BE NECESSARY FOR PORTIONS OF THE AREA.
STREAMS...CREEKS...AND RIVERS HAVE RESPONDED TO THE RECENT
RAINFALL...MOSTLY WITHIN BANK RISES. HOWEVER...REPEATED ROUNDS OF
HEAVY RAIN COULD PUSH SOME OF THE MORE FLASHY BASINS ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA TO NEAR FLOOD STAGE.

&&

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

$$

SHORT TERM...ZT
LONG TERM...ZT
AVIATION...BOYNE
HYDROLOGY...ZT

000
FXUS63 KARX 180900
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
400 AM CDT SAT MAY 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT MAY 18 2013

UPPER LEVEL RIDGING TAKING PLACE ACROSS THE UPPER MIDWEST TODAY AS
THE WESTERN CONUS TROUGH DEEPENS. PLENTY OF CONVECTION FIRING UP OFF
THE 850 MB LLJ IN CONJUNCTION WITH A PASSING SHORTWAVE ACROSS
CENTRAL MINNESOTA BACK INTO THE DAKOTAS. THIS ACTIVITY WILL MOSTLY
REMAIN NORTH/NORTHWEST OF THE FORECAST AREA...HOWEVER COULD CLIP
PORTIONS OF NORTH CENTRAL WISCONSIN BY MID TO LATE MORNING. LATEST
RUNS OF THE HRRR AND RAP SHOW CONVECTION WANING BUT POSSIBLY
IMPACTING TAYLOR AND CLARK COUNTIES IN WISCONSIN SO HAVE MAINTAINED
SHOWER/STORM CHANCES THERE. MOIST EASTERLY FLOW AND DECAYING
CIRRUS WILL KEEP SKIES MOSTLY CLOUDY TO OVERCAST THIS
MORNING...BUT AS THE MCS LIFTS NORTH...IT WILL PULL THE WARM FRONT
THROUGH THE AREA. PARTLY TO MOSTLY SUNNY SKIES WILL MOST LIKELY BE
SEEN ACROSS NORTHEAST IOWA WHERE THE FRONT IS ABLE TO CLEAR
THROUGH THE MOST.

DECENT INSTABILITY EXPECTED TODAY IN THE WARM SECTOR...AND MUCAPE
VALUES RANGE FROM 1000 TO 2000 J/KG IN A WEAKLY CAPPED ENVIRONMENT.
LACK OF SURFACE CONVERGENCE HOWEVER PRECLUDES HIGHER PRECIPITATION
CHANCES BUT MOST OF THE DETERMINISTIC AND PROBABILISTIC GUIDANCE
HINTS THAT CENTRAL WISCONSIN COULD SEE A STRAY SHOWER OR
THUNDERSTORM THIS AFTERNOON. HAVE MAINTAINED PRECIPITATION CHANCES
THERE. OTHERWISE...A WARM DAY ON TAP WITH LOWER TO MID 80S EXPECTED
SOUTH OF I-94.

RELATIVELY QUIET CONDITIONS TONIGHT AS CONVECTION IS EXPECTED TO
REMAIN WELL TO THE WEST AND NORTH. MILD NIGHT WITH SOUTHERLY
FLOW...AND OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT MAY 18 2013

FOCUS IS ON SEVERE WEATHER CHANCES SUNDAY AND MONDAY AS ACTIVE
WEATHER PATTERN SETS UP ACROSS MUCH OF THE CENTRAL PLAINS.

UPPER LEVEL NEGATIVE TILTED SHORTWAVE TROUGH EJECTS INTO THE CENTRAL
PLAINS ON SUNDAY...MEANWHILE AT THE SURFACE A FEW WAVES OF LOW PRESSURE
SHOULD BE DEVELOPING ACROSS OKLAHOMA INTO NEBRASKA. THIS WILL PULL
NORTH AMPLE GULF OF MEXICO MOISTURE...WITH PWATS INCREASING FROM
AROUND 1 INCH...TO NEARLY 1.75 INCHES...OR 175 PERCENT OF NORMAL.
SURFACE DEWPOINTS WILL RISE INTO THE LOW TO MIDDLE 60S. THERE SHOULD
BE CONVECTION ACROSS WESTERN IOWA INTO SOUTHWEST MINNESOTA EARLY
SUNDAY MORNING...WHICH WILL BE FEEDING OFF THE 850 MB LLJ. THIS
SHOULD WEAKEN AS IT APPROACHES THE WESTERN FORECAST AREA BUT GOOD
CONSENSUS THAT SHOWERS AND THUNDERSTORMS WILL BE AROUND IN THE
MORNING HOURS. THEN...THE BIG QUESTION BECOMES HOW MUCH CLEARING
WE WOULD SEE TO AID IN DESTABILIZATION. ASSUMING WE CLEAR
OUT...0-3KM MUCAPE IS EXPECTED TO INCREASE TO 1500-2000
J/KG...HIGHEST TO THE SOUTH AND WEST. OVERALL THE SHEAR PROFILES
ARE LESS IMPRESSIVE...BUT STILL SHOW 0-3KM BULK SHEAR OF NEARLY 30
KTS. THE ATMOSPHERE DOES REMAIN UNCAPPED SO EXPECTING GOOD CHANCES
OF CONVECTIVE INITIATION WITH ORGANIZED STORMS IN THE FORM OF
SUPERCELLS OR POSSIBLY BOWING SEGMENTS. STRONG TO SEVERE STORMS
WOULD DEVELOP ACROSS WESTERN INTO CENTRAL IOWA...AND TRACK
EAST/NORTHEAST THROUGH THE EVENING HOURS. THE PRIMARY THREATS ARE
LARGE HAIL AND DAMAGING WINDS. THE ENVIRONMENT STILL SUPPORTS AN
ISOLATED TORNADO...HOWEVER DEPENDING WHERE A WARM FRONT LAYS IS
MORE UNCERTAIN. 18.00Z GFS HAS THIS BOUNDARY ACROSS CENTRAL
IOWA...BUT 18.00Z ECMWF/NAM HINT THIS COULD BE FURTHER SOUTH.

THE WHOLE SYSTEM EDGES EASTWARD MONDAY...WITH THE BOTH THE
SURFACE AND UPPER LEVEL LOW BECOMING STACKED NEAR SIOUX FALLS SD
BY 12Z MONDAY. PIECES OF ENERGY WILL BE ROTATING THROUGH SOUTHERN
BEND OF THIS TROUGH...LIFTING THROUGH THE AREA DURING THE DAY. THE
SYNOPTIC SETUP IS SLIGHTLY MORE FAVORABLE FOR SEVERE WEATHER FOR
PARTS OF THE AREA. THE SHEAR PROFILES ARE MORE IMPRESSIVE WITH
0-6KM BULK SHEAR VALUES 40 TO 50 KTS ACROSS EASTERN IOWA INTO
SOUTHERN WISCONSIN. THE MORE LIMITING FACTOR THIS DAY IS HOW MUCH
DESTABILIZATION WILL OCCUR. THERE COULD BE SCATTERED SHOWERS AND
PLENTY OF CLOUDS AROUND TO LIMIT INSTABILITY. IF WE CAN BREAK OUT
AND FULLY DESTABILIZE...THEN 0-3KM MUCAPE MAY REACH 1500 TO 2000
J/KG. THE ENVIRONMENT SHOULD SUPPORT DISCRETE STORM CELLS...WITH
THE THREATS AGAIN LARGE HAIL AND DAMAGING WINDS.

TUESDAY AND BEYOND...THE UPPER LOW REMAINS NEARLY STATIONARY ACROSS
THE UPPER MIDWEST. THIS GIVES PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS THE ENTIRE AREA TUESDAY-THURSDAY. MODEL
CONSENSUS PAINTS 30 TO 60 PERCENT CHANCES WHICH IS APPROPRIATE AT
THIS TIME. FEEL THAT MUCH OF NEXT WEEK COULD BE UNSETTLED BUT SEE
LITTLE OPPORTUNITY TO PROVIDE MORE DETAILS IN WHAT PERIODS WOULD BE
MORE ACTIVE...SINCE TIMING PIECES OF ROTATING AROUND THE UPPER LOW
IS DIFFICULT THIS FAR OUT. THE BIGGER STORY WOULD BE THE HEIGHTENED
RISK FOR EXCESSIVE RAINFALL AND LOCALIZED FLOODING IF REPEATED
ROUNDS OF CONVECTION DO IMPACT THE AREA. BY MID-WEEK...SOILS WOULD
BECOME EVEN MORE SATURATED...AND FLASH GUIDANCE FURTHER REDUCED. SEE
HYDROLOGY SECTION BELOW FOR MORE DETAILS ON THAT RISK.

TEMPERATURE-WISE...WARMEST DAYS LOOK TO BE SUNDAY AND MONDAY BEFORE
A GRADUAL COOL DOWN TUESDAY...THEN TO BELOW NORMAL READINGS
WEDNESDAY THROUGH THURSDAY AS THE UPPER LOW DRIFTS OVERHEAD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1203 AM CDT SAT MAY 17 2013

GOES SATELLITE IMAGERY SHOWING A LARGE CONVECTIVE COMPLEX WITH
MASSIVE CIRRUS SHIELD HEADING OVER THE TAF SITES AFTER 06Z.
OBSERVATIONS OF CEILINGS ARE SHOWING INCREASING MIDLEVEL CLOUD
COVER NORTH OF THE TAF SITES WITH ERODING LOW-LEVEL IFR CIGS
NORTHWESTWARD. THIS IS THE OPPOSITE OF THE CURRENT TRENDS AT THE
TAF SITES WHICH HAVE IFR BUILDING IN OVERNIGHT.

THE HI RES RAPID REFRESH GUIDANCE CEILING FORECAST...WHICH SEEMS
TO HANDLE THE CURRENT SITUATION AND TREND VERY WELL...CONTINUES TO
ERODE THE IFR CIGS NORTHWEST AND AWAY FROM THE TAF SITES. HOWEVER...THE
TEMP/DEW POINT SPREADS ARE ONLY A FEW DEGREES...ESPECIALLY AT
KRST...THUS ANY COOLING MAY SATURATE THAT CLOUD LAYER.

A SLOW APPROACH TO AN IMPROVEMENT IN THE FORECAST SEEMS PRUDENT.
THUS...HAVE DELAYED ONSET OF IFR FOR THE 06Z TAFS. WILL CONTINUE TO
MONITOR THE TRENDS...BUT IFR MAY BE REMOVED FROM THE FORECAST IN
THE NEXT SEVERAL HOURS.

&&

.HYDROLOGY...SUNDAY AND INTO NEXT WEEK
ISSUED AT 400 AM CDT SAT MAY 18 2013

HEAVY RAINFALL /2 TO 2.5 INCHES/ FELL FRIDAY ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA...AND COMBINED WITH A RECORD
WET METEOROLOGICAL SPRING...RESULTS IN AN INCREASED RISK FOR
LOCALIZED FLASH FLOODING AS WE HEAD INTO THE LATTER PART OF THE
WEEKEND AND MUCH OF NEXT WEEK. PERIODS OF SHOWERS AND THUNDERSTORMS
LOOK TO IMPACT MUCH OF SOUTHEAST MINNESOTA AND NORTHEAST BEGINNING
SUNDAY AFTERNOON. AN ADDITIONAL 1 TO 3 INCHES IS POSSIBLE...AND IF
THIS FALLS IN A SHORT PERIOD...LOCALIZED FLASH FLOODING WOULD OCCUR.
THE 1 AND 3 HOUR FLASH GUIDANCE REMAINS WELL BELOW NORMAL...AND IS
GENERALLY LESS THAN 1 AND 2 INCHES...RESPECTIVELY. WPC CONTINUES THE
SLIGHT RISK OF EXCESSIVE RAINFALL AND FLASH FLOODING EARLY NEXT WEEK
ACROSS MUCH OF CENTRAL MINNESOTA INTO NORTHWEST WISCONSIN. A FLASH
FLOOD WATCH MAY BE NECESSARY FOR PORTIONS OF THE AREA.
STREAMS...CREEKS...AND RIVERS HAVE RESPONDED TO THE RECENT
RAINFALL...MOSTLY WITHIN BANK RISES. HOWEVER...REPEATED ROUNDS OF
HEAVY RAIN COULD PUSH SOME OF THE MORE FLASHY BASINS ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA TO NEAR FLOOD STAGE.

&&

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

$$

SHORT TERM...ZT
LONG TERM...ZT
AVIATION...BAUMGARDT
HYDROLOGY...ZT

000
FXUS63 KARX 180503
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1203 AM CDT SAT MAY 18 2013

.UPDATE...
ISSUED AT 643 PM CDT FRI MAY 17 2013

HAVE UPDATED THE FORECAST TO REMOVE THE THUNDER CHANCES IN WI AND
COUNTIES IMMEDIATELY ALONG THE MISSISSIPPI RIVER OVERNIGHT.

STATIONARY FRONTAL BOUNDARY CURRENTLY LIES JUST SW OF THE FORECAST
AREA FROM FAIRMONT MN TO WATERLOO AND THEN TO DAVENPORT IA. ALL
THE INSTABILITY IS ALONG THAT BOUNDARY AND ONLY SLIGHTLY EAST A
COUNTY OR TWO BEFORE STABILITY IS ENCOUNTERED. THE SURFACE
CONVERGENCE IS ALONG THE FRONT AND NO REAL FORCING IS GOING TO BE
IN PLAY OVERNIGHT. SO...HAVE LEFT ONLY AN ISOLATED THUNDER CHANCE
IN NERN IA AND SERN MN FOR THE NEXT HOURS.

AS DAYTIME HEATING DIMINISHES...WOULD EXPECT THE ACTIVITY OVER
SWRN/SC MN TO DIMINISH AS WELL. AT THIS TIME...THE STORMS ARE
REMAINING ON THE BOUNDARY AND DO NOT POSE A RISK TO THE AREA.
LITTLE IN THE WAY OF ADDITIONAL FORCING FOR DEVELOPMENT IS
EXPECTED IN THE NEAR TERM.

BIGGEST ISSUE TONIGHT MAY BE WIDESPREAD LOW CLOUD AND FOG AS THE
CURRENT SURFACE OBSERVATIONS INDICATE VERY LOW DEW POINT
DEPRESSIONS /3-7F/ FROM ABOUT I-90 AND NORTH. WITH ONLY THE CIRRUS
MOVING OVERHEAD DURING THE NEXT FEW HOURS FROM THE CURRENT UPSTREAM
CONVECTION...EXPECTED TO DISSIPATE...STRATUS/FOG WILL DEVELOP OVER/INTO THE
AREA BY LATE EVENING. SOME BOUNDARY LAYER WIND MAY HELP PREVENT
WIDESPREAD DENSE FOG...BUT WOULD THINK THE INVERSION AND BEING
NORTH OF THE STATIONARY BOUNDARY...WITH MOIST CONDITIONS
ALREADY...SPELL SOME FOG. CURRENTLY COLLABORATING THIS IDEA WITH
NEIGHBORING OFFICES.

HAVE HAD SOME RISES ON THE CEDAR BASIN STREAMS/RIVER WITH TODAYS 2
INCHES. HAVE ISSUED STATEMENTS ON THESE WITHIN BANK RISES.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 341 PM CDT FRI MAY 17 2013

LATEST SURFACE OBSERVATIONS PLACED A WARM FRONT EXTENDING FROM
BOOKINGS SOUTH DAKOTA...EXTENDING SOUTHEAST THROUGH SOUTHERN
MINNESOTA...TO NEAR FAIRMONT MINNESOTA...INTO EAST CENTRAL IOWA. THE
FRONT WAS NEARLY STATIONARY THIS AFTERNOON BUT WILL START TO SLOWLY
ADVANCE NORTHWARD TONIGHT. WATER VAPOR IMAGERY AND 500 MB RAP
ANALYSIS SHOWED AN ACTIVE PATTERN ACROSS THE CONUS. A VIGOROUS TROUGH
WAS DIVING INTO THE CENTRAL ROCKIES...PUSHING EAST. A SHORTWAVE WAS
MOVING ACROSS SOUTHERN MINNESOTA/NORTHERN THROUGH SOUTHERN WISCONSIN
AND WAS GENERATING A PERSISTENT BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS. HEAVY RAIN HAS FALLEN ACROSS PORTIONS OF NORTH
CENTRAL IOWA INTO SOUTHEAST MINNESOTA.

KEEPING A VERY CLOSE WATCH ON THE WARM FRONT LATE THIS AFTERNOON INTO
THIS EVENING WITH ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT
EXPECTED ALONG IT. A CONVERGENT AREA WAS NOTED IN THE SURFACE WINDS
FIELDS OVER SOUTHWEST MINNESOTA...AND SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED ACROSS THESE AREAS. ALL OF THE MESOSCALE MODEL GUIDANCE IS
SUGGESTING THAT THIS AREA OF SHOWERS AND STORMS WILL CONTINUE AND
DRIFT SOUTHEAST ALONG THE FRONT LATE THIS AFTERNOON INTO THIS
EVENING. A VERY UNSTABLE AIRMASS IS FEEDING INTO THE WARM FRONT.
WHERE THERE HAS BEEN SUN THIS AFTERNOON...SURFACE BASES CAPE VALUES
HAVE CLIMBED TO AROUND 2000 J/KG. A RATHER MOIST AIRMASS IN PLACE
OVER THE AREA WITH PRECIPITABLE WATER VALUES OF 1.2 TO 1.3 INCHES.
THE SHOWERS AND THUNDERSTORMS HAVE BEEN VERY EFFICIENT RAIN
PRODUCERS TODAY AND WITH THIS MOIST AIRMASS IN PLACE...ANY
ADDITIONAL SHOWERS AND STORMS WOULD ALSO BE EFFICIENT RAIN
PRODUCERS. 0-6 KM SHEAR IS RATHER WEAK SO THINKING THE MAIN SEVERE
WEATHER THREAT WITH ANY THUNDERSTORMS TONIGHT WOULD BE PERIODS OF
HEAVY RAINFALL. CANNOT RULE OUT AN ISOLATED STORM OR TWO WITH LARGE
HAIL. THE MAIN CONCERN FOR THIS ACTIVITY IS ACROSS PORTIONS OF
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA.

A THUNDERSTORM COMPLEX WILL FIRE OVER WESTERN SOUTH DAKOTA AND RACE
EAST TONIGHT. INSTABILITY REALLY WANES LATE THIS EVENING...WITH 0-3
KM MUCAPE VALUES FALLING TO 300 J/KG ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA MAINLY AFTER 6Z TONIGHT. THINKING THE THUNDERSTORMS
WILL REALLY START TO DIE OFF WHEN THEY APPROACH THE INTERSTATE 35
CORRIDOR. THE STRONGEST 850 MB MOISTURE TRANSPORT STAYS FOCUSED INTO
EASTERN SOUTH DAKOTA THROUGH THE LATE NIGHT HOURS SO A WEAKENING
TREND SEEMS REASONABLE AND THE MESOSCALE MODELS ARE ALSO IN LINE
WITH THIS.

EARLY SATURDAY MORNING...THE WARM FRONT IS EXPECTED TO SLOWLY LIFT
NORTH OF THE INTERSTATE 90 CORRIDOR. CLOUD COVER OVER CENTRAL AND
NORTHERN WISCONSIN MAY SLOW ITS ADVANCE TO THE NORTH WITH THE COOLER
AIR UNDER CLOUD COVER TO THE NORTH AND SOME SUNSHINE SOUTH OF THE
WARM FRONT. FORECAST MODELS HAVE BEEN GENERATING SOME LIGHT PRECIPITATION
ACROSS AREAS RIGHT ALONG AND EAST OF THE MISSISSIPPI RIVER LATE
SATURDAY MORNING INTO SATURDAY AFTERNOON. THERE REALLY ISN/T ANY
APPRECIABLE FORCING ALOFT TO WORK WITH BUT FORECAST SOUNDINGS SHOW
CAPE VALUES INCREASING TO AROUND 1500 J/KG ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND TO AROUND 300 J/KG OVER NORTH CENTRAL
WISCONSIN. HAVE EXTENDED SHOWER/THUNDERSTORM CHANCES A BIT FURTHER
SOUTH OVER THE PREVIOUS FORECAST TO ACCOUNT FOR THE INSTABILITY AND
SLOWER MOVEMENT OF THE WARM FRONT. IT WILL BE RATHER WARM ON
SATURDAY IN THE WAKE OF THE WARM FRONT WITH HIGHS CLIMBING INTO THE
LOWER TO MID 80S OVER NORTHEAST IOWA...SOUTHEAST MINNESOTA AND FAR
WESTERN WISCONSIN. IT WILL BE  A LITTLE COOLER ACROSS NORTH CENTRAL
WISCONSIN WHERE HIGHS WILL STRUGGLE TO GET OUT OF THE LOWER 70S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 341 PM CDT FRI MAY 17 2013

A VERY ACTIVE PATTERN IS IN STORE FOR THE REGION SUNDAY THROUGH
MONDAY WITH SEVERE WEATHER POSSIBLE. THUNDERSTORMS FIRING OVER THE
DAKOTAS INTO THE CENTRAL PLAINS AND MOVING EAST INTO THE FORECAST
AREA SUNDAY MORNING WILL HAVE AN IMPACT ON CONVECTION FOR SUNDAY
AFTERNOON.

A POTENT SHORTWAVE EJECTS OUT OF THE CENTRAL PLAINS SUNDAY AFTERNOON
AND LIFTS NORTH INTO THE UPPER MISSISSIPPI RIVER VALLEY...BECOMING
NEGATIVELY TILTED.  MEANWHILE...SURFACE LOW PRESSURE DEEPENS OVER
SOUTHEAST SOUTH DAKOTA...AND A SECONDARY WARM FRONT DEVELOPS OVER
NORTHERN IOWA AND LIFTS NORTH INTO SOUTHERN MINNESOTA EARLY SUNDAY
EVENING. 0-3KM MUCAPE VALUES INCREASE TO 1200-1500 J/KG LATE SUNDAY
AFTERNOON ACROSS NORTHERN IOWA/SOUTHERN MINNESOTA AND SOUTHWEST
WISCONSIN. 0-6 KM SHEAR INCREASES AS THE WAVE MOVES INTO THE
AREA...INCREASING TO 30 TO 45 KTS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER...OVERALL
RATHER IMPRESSIVE LOW LEVEL SHEAR PROFILES. LATEST THINKING IS THAT
THUNDERSTORMS WILL ERUPT OVER PORTIONS OF WESTERN IOWA SUNDAY
AFTERNOON WITH ADDITIONAL DEVELOP POSSIBLE TO THE NORTHEAST ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA....AND POTENTIALLY INTO
SOUTHWEST WISCONSIN.  SHEAR PROFILES WOULD FAVOR SUPERCELL
STRUCTURES. SINCE MOST OF THE SHEAR IS LOCATED IN THE 0-3 KM
LAYER...THERE IS GROWING CONCERN FOR DAMAGING WINDS AND BOWING
STRUCTURES WITH THE STORMS. ISOLATED TORNADOES ARE ALSO POSSIBLE.
ALSO...THERE IS THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY SUNDAY
EVENING AS 850 MB MOISTURE TRANSPORT INCREASES ACROSS NORTHERN
IOWA/SOUTHERN MINNESOTA AND SOUTHWEST WISCONSIN...FOCUSING INTO THE
WARM FRONT.

A BROAD UPPER TROUGH OVER THE UPPER MIDWEST WILL FINALLY CLOSE INTO
AN UPPER LOW ON MONDAY. SEVERAL PIECES OF ENERGY ROTATING AROUND THE
LOW WILL BRING ADDITIONAL CHANCE FOR SHOWERS AND THUNDERSTORMS TO
THE AREA. THINKING THE BULK OF THE INSTABILITY SHOULD BE SOUTHEAST
OF THE FORECAST AREA SO IT APPEARS THE GREATEST SEVERE THREAT SHOULD
BE SOUTHEAST OF THE AREA...BUT THIS WILL DEPEND ON HOW THE
CONVECTION PLAYS OUT SUNDAY NIGHT. THE UPPER LOW CONTINUES TO SPIN
OVER THE REGION THROUGH MIDWEEK WITH DAILY CHANCES FOR SHOWERS AND
POSSIBLE THUNDERSTORMS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1203 PM CDT FRI MAY 17 2013

GOES SATELLITE IMAGERY SHOWING A LARGE CONVECTIVE COMPLEX WITH
MASSIVE CIRRUS SCHIELD HEADING OVER THE TAF SITES AFTER 06Z.
OBSERVATIONS OF CEILINGS ARE SHOWING INCREASING MIDLEVEL CLOUD
COVER NORTH OF THE TAF SITES WITH ERODING LOW-LEVEL IFR CIGS
NORTHWESTWARD. THIS IS THE OPPOSITE OF THE CURRENT TRENDS AT THE
TAF SITES WHICH HAVE IFR BUILDING IN OVERNIGHT.

THE HI RES RAPID REFRESH GUIDANCE CEILING FORECAST...WHICH SEEMS
TO HANDLE THE CURRENT SITUATION AND TREND VERY WELL...CONTINUES TO
ERODE THE IFR CIGS NORTHWEST AND AWAY FROM THE TAF SITES. HOWEVER...THE
TEMP/DEW POINT SPREADS ARE ONLY A FEW DEGREES...ESPECIALLY AT
KRST...THUS ANY COOLING MAY SATURATE THAT CLOUD LAYER.

A SLOW APPROACH TO AN IMPROVEMENT IN THE FORECAST SEEMS PRUDENT.
THUS...HAVE DELAYED ONSET OF IFR FOR THE 06Z TAFS. WILL CONTINUE TO
MONITOR THE TRENDS...BUT IFR MAY BE REMOVED FROM THE FORECAST IN
THE NEXT SEVERAL HOURS.

&&

.HYDROLOGY...THIS EVENING THROUGH MONDAY
ISSUED AT 341 PM CDT FRI MAY 17 2013

PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF SOUTHEAST
MINNESOTA INTO NORTHEAST IOWA HAVE PRODUCED 2 TO NEARLY 2 1/2
INCHES OF RAINFALL SO FAR TODAY. SCATTERED THUNDERSTORMS ARE
EXPECTED LATE THIS AFTERNOON INTO EARLY THIS EVENING. THE STORMS
ARE SLOW MOVING AND WILL HAVE THE POTENTIAL TO PRODUCE PERIODS OF
HEAVY RAINFALL...WHICH COULD LEAD TO FLOODING...ESPECIALLY ACROSS
THOSE AREAS THAT HAVE ALREADY SEEN HEAVY RAINFALL.

THUNDERSTORMS ARE EXPECTED SUNDAY AFTERNOON THROUGH MONDAY. THE
STORMS COULD PRODUCE PERIODS OF HEAVY RAINFALL WHICH COULD LEAD TO
FLOODING. 1 TO 3 INCHES OF ADDITIONAL RAINFALL IS POSSIBLE FROM
SUNDAY INTO WEDNESDAY. A FLASH FLOOD WATCH MAY BE NEEDED IF
CONFIDENCE INCREASES ON WHERE THE HEAVIEST RAIN WILL FALL.

&&

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

$$

UPDATE...BAUMGARDT
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...BAUMGARDT
HYDROLOGY...WETENKAMP

000
FXUS63 KARX 180020
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
720 PM CDT FRI MAY 17 2013

.UPDATE...
ISSUED AT 643 PM CDT FRI MAY 17 2013

HAVE UPDATED THE FORECAST TO REMOVE THE THUNDER CHANCES IN WI AND
COUNTIES IMMEDIATELY ALONG THE MISSISSIPPI RIVER OVERNIGHT.

STATIONARY FRONTAL BOUNDARY CURRENTLY LIES JUST SW OF THE FORECAST
AREA FROM FAIRMONT MN TO WATERLOO AND THEN TO DAVENPORT IA. ALL
THE INSTABILITY IS ALONG THAT BOUNDARY AND ONLY SLIGHTLY EAST A
COUNTY OR TWO BEFORE STABILITY IS ENCOUNTERED. THE SURFACE
CONVERGENCE IS ALONG THE FRONT AND NO REAL FORCING IS GOING TO BE
IN PLAY OVERNIGHT. SO...HAVE LEFT ONLY AN ISOLATED THUNDER CHANCE
IN NERN IA AND SERN MN FOR THE NEXT HOURS.

AS DAYTIME HEATING DIMINISHES...WOULD EXPECT THE ACTIVITY OVER
SWRN/SC MN TO DIMINISH AS WELL. AT THIS TIME...THE STORMS ARE
REMAINING ON THE BOUNDARY AND DO NOT POSE A RISK TO THE AREA.
LITTLE IN THE WAY OF ADDITIONAL FORCING FOR DEVELOPMENT IS
EXPECTED IN THE NEAR TERM.

BIGGEST ISSUE TONIGHT MAY BE WIDESPREAD LOW CLOUD AND FOG AS THE
CURRENT SURFACE OBSERVATIONS INDICATE VERY LOW DEW POINT
DEPRESSIONS /3-7F/ FROM ABOUT I-90 AND NORTH. WITH ONLY THE CIRRUS
MOVING OVERHEAD DURING THE NEXT FEW HOURS FROM THE CURRENT UPSTREAM
CONVECTION...EXPECTED TO DISSIPATE...STRATUS/FOG WILL DEVELOP OVER/INTO THE
AREA BY LATE EVENING. SOME BOUNDARY LAYER WIND MAY HELP PREVENT
WIDESPREAD DENSE FOG...BUT WOULD THINK THE INVERSION AND BEING
NORTH OF THE STATIONARY BOUNDARY...WITH MOIST CONDITIONS
ALREADY...SPELL SOME FOG. CURRENTLY COLLABORATING THIS IDEA WITH
NEIGHBORING OFFICES.

HAVE HAD SOME RISES ON THE CEDAR BASIN STREAMS/RIVER WITH TODAYS 2
INCHES. HAVE ISSUED STATEMENTS ON THESE WITHIN BANK RISES.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 341 PM CDT FRI MAY 17 2013

LATEST SURFACE OBSERVATIONS PLACED A WARM FRONT EXTENDING FROM
BOOKINGS SOUTH DAKOTA...EXTENDING SOUTHEAST THROUGH SOUTHERN
MINNESOTA...TO NEAR FAIRMONT MINNESOTA...INTO EAST CENTRAL IOWA. THE
FRONT WAS NEARLY STATIONARY THIS AFTERNOON BUT WILL START TO SLOWLY
ADVANCE NORTHWARD TONIGHT. WATER VAPOR IMAGERY AND 500 MB RAP
ANALYSIS SHOWED AN ACTIVE PATTERN ACROSS THE CONUS. A VIGOROUS TROUGH
WAS DIVING INTO THE CENTRAL ROCKIES...PUSHING EAST. A SHORTWAVE WAS
MOVING ACROSS SOUTHERN MINNESOTA/NORTHERN THROUGH SOUTHERN WISCONSIN
AND WAS GENERATING A PERSISTENT BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS. HEAVY RAIN HAS FALLEN ACROSS PORTIONS OF NORTH
CENTRAL IOWA INTO SOUTHEAST MINNESOTA.

KEEPING A VERY CLOSE WATCH ON THE WARM FRONT LATE THIS AFTERNOON INTO
THIS EVENING WITH ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT
EXPECTED ALONG IT. A CONVERGENT AREA WAS NOTED IN THE SURFACE WINDS
FIELDS OVER SOUTHWEST MINNESOTA...AND SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED ACROSS THESE AREAS. ALL OF THE MESOSCALE MODEL GUIDANCE IS
SUGGESTING THAT THIS AREA OF SHOWERS AND STORMS WILL CONTINUE AND
DRIFT SOUTHEAST ALONG THE FRONT LATE THIS AFTERNOON INTO THIS
EVENING. A VERY UNSTABLE AIRMASS IS FEEDING INTO THE WARM FRONT.
WHERE THERE HAS BEEN SUN THIS AFTERNOON...SURFACE BASES CAPE VALUES
HAVE CLIMBED TO AROUND 2000 J/KG. A RATHER MOIST AIRMASS IN PLACE
OVER THE AREA WITH PRECIPITABLE WATER VALUES OF 1.2 TO 1.3 INCHES.
THE SHOWERS AND THUNDERSTORMS HAVE BEEN VERY EFFICIENT RAIN
PRODUCERS TODAY AND WITH THIS MOIST AIRMASS IN PLACE...ANY
ADDITIONAL SHOWERS AND STORMS WOULD ALSO BE EFFICIENT RAIN
PRODUCERS. 0-6 KM SHEAR IS RATHER WEAK SO THINKING THE MAIN SEVERE
WEATHER THREAT WITH ANY THUNDERSTORMS TONIGHT WOULD BE PERIODS OF
HEAVY RAINFALL. CANNOT RULE OUT AN ISOLATED STORM OR TWO WITH LARGE
HAIL. THE MAIN CONCERN FOR THIS ACTIVITY IS ACROSS PORTIONS OF
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA.

A THUNDERSTORM COMPLEX WILL FIRE OVER WESTERN SOUTH DAKOTA AND RACE
EAST TONIGHT. INSTABILITY REALLY WANES LATE THIS EVENING...WITH 0-3
KM MUCAPE VALUES FALLING TO 300 J/KG ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA MAINLY AFTER 6Z TONIGHT. THINKING THE THUNDERSTORMS
WILL REALLY START TO DIE OFF WHEN THEY APPROACH THE INTERSTATE 35
CORRIDOR. THE STRONGEST 850 MB MOISTURE TRANSPORT STAYS FOCUSED INTO
EASTERN SOUTH DAKOTA THROUGH THE LATE NIGHT HOURS SO A WEAKENING
TREND SEEMS REASONABLE AND THE MESOSCALE MODELS ARE ALSO IN LINE
WITH THIS.

EARLY SATURDAY MORNING...THE WARM FRONT IS EXPECTED TO SLOWLY LIFT
NORTH OF THE INTERSTATE 90 CORRIDOR. CLOUD COVER OVER CENTRAL AND
NORTHERN WISCONSIN MAY SLOW ITS ADVANCE TO THE NORTH WITH THE COOLER
AIR UNDER CLOUD COVER TO THE NORTH AND SOME SUNSHINE SOUTH OF THE
WARM FRONT. FORECAST MODELS HAVE BEEN GENERATING SOME LIGHT PRECIPITATION
ACROSS AREAS RIGHT ALONG AND EAST OF THE MISSISSIPPI RIVER LATE
SATURDAY MORNING INTO SATURDAY AFTERNOON. THERE REALLY ISN/T ANY
APPRECIABLE FORCING ALOFT TO WORK WITH BUT FORECAST SOUNDINGS SHOW
CAPE VALUES INCREASING TO AROUND 1500 J/KG ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND TO AROUND 300 J/KG OVER NORTH CENTRAL
WISCONSIN. HAVE EXTENDED SHOWER/THUNDERSTORM CHANCES A BIT FURTHER
SOUTH OVER THE PREVIOUS FORECAST TO ACCOUNT FOR THE INSTABILITY AND
SLOWER MOVEMENT OF THE WARM FRONT. IT WILL BE RATHER WARM ON
SATURDAY IN THE WAKE OF THE WARM FRONT WITH HIGHS CLIMBING INTO THE
LOWER TO MID 80S OVER NORTHEAST IOWA...SOUTHEAST MINNESOTA AND FAR
WESTERN WISCONSIN. IT WILL BE  A LITTLE COOLER ACROSS NORTH CENTRAL
WISCONSIN WHERE HIGHS WILL STRUGGLE TO GET OUT OF THE LOWER 70S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 341 PM CDT FRI MAY 17 2013

A VERY ACTIVE PATTERN IS IN STORE FOR THE REGION SUNDAY THROUGH
MONDAY WITH SEVERE WEATHER POSSIBLE. THUNDERSTORMS FIRING OVER THE
DAKOTAS INTO THE CENTRAL PLAINS AND MOVING EAST INTO THE FORECAST
AREA SUNDAY MORNING WILL HAVE AN IMPACT ON CONVECTION FOR SUNDAY
AFTERNOON.

A POTENT SHORTWAVE EJECTS OUT OF THE CENTRAL PLAINS SUNDAY AFTERNOON
AND LIFTS NORTH INTO THE UPPER MISSISSIPPI RIVER VALLEY...BECOMING
NEGATIVELY TILTED.  MEANWHILE...SURFACE LOW PRESSURE DEEPENS OVER
SOUTHEAST SOUTH DAKOTA...AND A SECONDARY WARM FRONT DEVELOPS OVER
NORTHERN IOWA AND LIFTS NORTH INTO SOUTHERN MINNESOTA EARLY SUNDAY
EVENING. 0-3KM MUCAPE VALUES INCREASE TO 1200-1500 J/KG LATE SUNDAY
AFTERNOON ACROSS NORTHERN IOWA/SOUTHERN MINNESOTA AND SOUTHWEST
WISCONSIN. 0-6 KM SHEAR INCREASES AS THE WAVE MOVES INTO THE
AREA...INCREASING TO 30 TO 45 KTS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER...OVERALL
RATHER IMPRESSIVE LOW LEVEL SHEAR PROFILES. LATEST THINKING IS THAT
THUNDERSTORMS WILL ERUPT OVER PORTIONS OF WESTERN IOWA SUNDAY
AFTERNOON WITH ADDITIONAL DEVELOP POSSIBLE TO THE NORTHEAST ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA....AND POTENTIALLY INTO
SOUTHWEST WISCONSIN.  SHEAR PROFILES WOULD FAVOR SUPERCELL
STRUCTURES. SINCE MOST OF THE SHEAR IS LOCATED IN THE 0-3 KM
LAYER...THERE IS GROWING CONCERN FOR DAMAGING WINDS AND BOWING
STRUCTURES WITH THE STORMS. ISOLATED TORNADOES ARE ALSO POSSIBLE.
ALSO...THERE IS THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY SUNDAY
EVENING AS 850 MB MOISTURE TRANSPORT INCREASES ACROSS NORTHERN
IOWA/SOUTHERN MINNESOTA AND SOUTHWEST WISCONSIN...FOCUSING INTO THE
WARM FRONT.

A BROAD UPPER TROUGH OVER THE UPPER MIDWEST WILL FINALLY CLOSE INTO
AN UPPER LOW ON MONDAY. SEVERAL PIECES OF ENERGY ROTATING AROUND THE
LOW WILL BRING ADDITIONAL CHANCE FOR SHOWERS AND THUNDERSTORMS TO
THE AREA. THINKING THE BULK OF THE INSTABILITY SHOULD BE SOUTHEAST
OF THE FORECAST AREA SO IT APPEARS THE GREATEST SEVERE THREAT SHOULD
BE SOUTHEAST OF THE AREA...BUT THIS WILL DEPEND ON HOW THE
CONVECTION PLAYS OUT SUNDAY NIGHT. THE UPPER LOW CONTINUES TO SPIN
OVER THE REGION THROUGH MIDWEEK WITH DAILY CHANCES FOR SHOWERS AND
POSSIBLE THUNDERSTORMS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 643 PM CDT FRI MAY 17 2013

CONTINUED THE IDEA IN THE TAFS OF AN IFR/LIFR CIG STRATUS
DEVELOPING OVERNIGHT. SURFACE OBSERVATIONS HAVE VERY LOW DEWPOINT-
TEMPERATURE SPREADS AND ANY AREAS NOT IN THE CLOUDS NOT WILL
LIKELY RADIATE AND FORM THE STRATUS. HAVE DECIDED TO LOWER
CONDITIONS AND HOLD THEM IFR LONGER IN THE MORNING WITH THIS
FORECAST. THIS APPEARS TO BE AN AFTERNOON MIX OUT OF THE
CLOUDS/FOG AND IMPROVING CONDITIONS TO MVFR AS THE FRONTAL
BOUNDARY THAT IS IN THE AREA LIFTS NORTHEAST.

CONFIDENCE ON THE LOW CIGS IS HIGH WITH MOIST CONDITIONS IN NEAR-
SURFACE LAYER...FRESH RAINFALL...SOME CLEARING WHERE IS NOT
CLOUDY...AND BEING LOCATED NORTH OF A STATIONARY BOUNDARY CAUSING
A TEMPERATURE INVERSION OVER THE TAF SITES THROUGH THE MORNING.

&&

.HYDROLOGY...THIS EVENING THROUGH MONDAY
ISSUED AT 341 PM CDT FRI MAY 17 2013

PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF SOUTHEAST
MINNESOTA INTO NORTHEAST IOWA HAVE PRODUCED 2 TO NEARLY 2 1/2
INCHES OF RAINFALL SO FAR TODAY. SCATTERED THUNDERSTORMS ARE
EXPECTED LATE THIS AFTERNOON INTO EARLY THIS EVENING. THE STORMS
ARE SLOW MOVING AND WILL HAVE THE POTENTIAL TO PRODUCE PERIODS OF
HEAVY RAINFALL...WHICH COULD LEAD TO FLOODING...ESPECIALLY ACROSS
THOSE AREAS THAT HAVE ALREADY SEEN HEAVY RAINFALL.

THUNDERSTORMS ARE EXPECTED SUNDAY AFTERNOON THROUGH MONDAY. THE
STORMS COULD PRODUCE PERIODS OF HEAVY RAINFALL WHICH COULD LEAD TO
FLOODING. 1 TO 3 INCHES OF ADDITIONAL RAINFALL IS POSSIBLE FROM
SUNDAY INTO WEDNESDAY. A FLASH FLOOD WATCH MAY BE NEEDED IF
CONFIDENCE INCREASES ON WHERE THE HEAVIEST RAIN WILL FALL.

&&

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

$$

UPDATE...BAUMGARDT
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...BAUMGARDT
HYDROLOGY...WETENKAMP

000
FXUS63 KARX 172041
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
341 PM CDT FRI MAY 17 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 341 PM CDT FRI MAY 17 2013

LATEST SURFACE OBSERVATIONS PLACED A WARM FRONT EXTENDING FROM
BOOKINGS SOUTH DAKOTA...EXTENDING SOUTHEAST THROUGH SOUTHERN
MINNESOTA...TO NEAR FAIRMONT MINNESOTA...INTO EAST CENTRAL IOWA. THE
FRONT WAS NEARLY STATIONARY THIS AFTERNOON BUT WILL START TO SLOWLY
ADVANCE NORTHWARD TONIGHT. WATER VAPOR IMAGERY AND 500 MB RAP
ANALYSIS SHOWED AN ACTIVE PATTERN ACROSS THE CONUS. A VIGOROUS TROUGH
WAS DIVING INTO THE CENTRAL ROCKIES...PUSHING EAST. A SHORTWAVE WAS
MOVING ACROSS SOUTHERN MINNESOTA/NORTHERN THROUGH SOUTHERN WISCONSIN
AND WAS GENERATING A PERSISTENT BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS. HEAVY RAIN HAS FALLEN ACROSS PORTIONS OF NORTH
CENTRAL IOWA INTO SOUTHEAST MINNESOTA.

KEEPING A VERY CLOSE WATCH ON THE WARM FRONT LATE THIS AFTERNOON INTO
THIS EVENING WITH ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT
EXPECTED ALONG IT. A CONVERGENT AREA WAS NOTED IN THE SURFACE WINDS
FIELDS OVER SOUTHWEST MINNESOTA...AND SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED ACROSS THESE AREAS. ALL OF THE MESOSCALE MODEL GUIDANCE IS
SUGGESTING THAT THIS AREA OF SHOWERS AND STORMS WILL CONTINUE AND
DRIFT SOUTHEAST ALONG THE FRONT LATE THIS AFTERNOON INTO THIS
EVENING. A VERY UNSTABLE AIRMASS IS FEEDING INTO THE WARM FRONT.
WHERE THERE HAS BEEN SUN THIS AFTERNOON...SURFACE BASES CAPE VALUES
HAVE CLIMBED TO AROUND 2000 J/KG. A RATHER MOIST AIRMASS IN PLACE
OVER THE AREA WITH PRECIPITABLE WATER VALUES OF 1.2 TO 1.3 INCHES.
THE SHOWERS AND THUNDERSTORMS HAVE BEEN VERY EFFICIENT RAIN
PRODUCERS TODAY AND WITH THIS MOIST AIRMASS IN PLACE...ANY
ADDITIONAL SHOWERS AND STORMS WOULD ALSO BE EFFICIENT RAIN
PRODUCERS. 0-6 KM SHEAR IS RATHER WEAK SO THINKING THE MAIN SEVERE
WEATHER THREAT WITH ANY THUNDERSTORMS TONIGHT WOULD BE PERIODS OF
HEAVY RAINFALL. CANNOT RULE OUT AN ISOLATED STORM OR TWO WITH LARGE
HAIL. THE MAIN CONCERN FOR THIS ACTIVITY IS ACROSS PORTIONS OF
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA.

A THUNDERSTORM COMPLEX WILL FIRE OVER WESTERN SOUTH DAKOTA AND RACE
EAST TONIGHT. INSTABILITY REALLY WANES LATE THIS EVENING...WITH 0-3
KM MUCAPE VALUES FALLING TO 300 J/KG ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA MAINLY AFTER 6Z TONIGHT. THINKING THE THUNDERSTORMS
WILL REALLY START TO DIE OFF WHEN THEY APPROACH THE INTERSTATE 35
CORRIDOR. THE STRONGEST 850 MB MOISTURE TRANSPORT STAYS FOCUSED INTO
EASTERN SOUTH DAKOTA THROUGH THE LATE NIGHT HOURS SO A WEAKENING
TREND SEEMS REASONABLE AND THE MESOSCALE MODELS ARE ALSO IN LINE
WITH THIS.

EARLY SATURDAY MORNING...THE WARM FRONT IS EXPECTED TO SLOWLY LIFT
NORTH OF THE INTERSTATE 90 CORRIDOR. CLOUD COVER OVER CENTRAL AND
NORTHERN WISCONSIN MAY SLOW ITS ADVANCE TO THE NORTH WITH THE COOLER
AIR UNDER CLOUD COVER TO THE NORTH AND SOME SUNSHINE SOUTH OF THE
WARM FRONT. FORECAST MODELS HAVE BEEN GENERATING SOME LIGHT PRECIPITATION
ACROSS AREAS RIGHT ALONG AND EAST OF THE MISSISSIPPI RIVER LATE
SATURDAY MORNING INTO SATURDAY AFTERNOON. THERE REALLY ISN/T ANY
APPRECIABLE FORCING ALOFT TO WORK WITH BUT FORECAST SOUNDINGS SHOW
CAPE VALUES INCREASING TO AROUND 1500 J/KG ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND TO AROUND 300 J/KG OVER NORTH CENTRAL
WISCONSIN. HAVE EXTENDED SHOWER/THUNDERSTORM CHANCES A BIT FURTHER
SOUTH OVER THE PREVIOUS FORECAST TO ACCOUNT FOR THE INSTABILITY AND
SLOWER MOVEMENT OF THE WARM FRONT. IT WILL BE RATHER WARM ON
SATURDAY IN THE WAKE OF THE WARM FRONT WITH HIGHS CLIMBING INTO THE
LOWER TO MID 80S OVER NORTHEAST IOWA...SOUTHEAST MINNESOTA AND FAR
WESTERN WISCONSIN. IT WILL BE  A LITTLE COOLER ACROSS NORTH CENTRAL
WISCONSIN WHERE HIGHS WILL STRUGGLE TO GET OUT OF THE LOWER 70S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 341 PM CDT FRI MAY 17 2013

A VERY ACTIVE PATTERN IS IN STORE FOR THE REGION SUNDAY THROUGH
MONDAY WITH SEVERE WEATHER POSSIBLE. THUNDERSTORMS FIRING OVER THE
DAKOTAS INTO THE CENTRAL PLAINS AND MOVING EAST INTO THE FORECAST
AREA SUNDAY MORNING WILL HAVE AN IMPACT ON CONVECTION FOR SUNDAY
AFTERNOON.

A POTENT SHORTWAVE EJECTS OUT OF THE CENTRAL PLAINS SUNDAY AFTERNOON
AND LIFTS NORTH INTO THE UPPER MISSISSIPPI RIVER VALLEY...BECOMING
NEGATIVELY TILTED.  MEANWHILE...SURFACE LOW PRESSURE DEEPENS OVER
SOUTHEAST SOUTH DAKOTA...AND A SECONDARY WARM FRONT DEVELOPS OVER
NORTHERN IOWA AND LIFTS NORTH INTO SOUTHERN MINNESOTA EARLY SUNDAY
EVENING. 0-3KM MUCAPE VALUES INCREASE TO 1200-1500 J/KG LATE SUNDAY
AFTERNOON ACROSS NORTHERN IOWA/SOUTHERN MINNESOTA AND SOUTHWEST
WISCONSIN. 0-6 KM SHEAR INCREASES AS THE WAVE MOVES INTO THE
AREA...INCREASING TO 30 TO 45 KTS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER...OVERALL
RATHER IMPRESSIVE LOW LEVEL SHEAR PROFILES. LATEST THINKING IS THAT
THUNDERSTORMS WILL ERUPT OVER PORTIONS OF WESTERN IOWA SUNDAY
AFTERNOON WITH ADDITIONAL DEVELOP POSSIBLE TO THE NORTHEAST ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA....AND POTENTIALLY INTO
SOUTHWEST WISCONSIN.  SHEAR PROFILES WOULD FAVOR SUPERCELL
STRUCTURES. SINCE MOST OF THE SHEAR IS LOCATED IN THE 0-3 KM
LAYER...THERE IS GROWING CONCERN FOR DAMAGING WINDS AND BOWING
STRUCTURES WITH THE STORMS. ISOLATED TORNADOES ARE ALSO POSSIBLE.
ALSO...THERE IS THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY SUNDAY
EVENING AS 850 MB MOISTURE TRANSPORT INCREASES ACROSS NORTHERN
IOWA/SOUTHERN MINNESOTA AND SOUTHWEST WISCONSIN...FOCUSING INTO THE
WARM FRONT.

A BROAD UPPER TROUGH OVER THE UPPER MIDWEST WILL FINALLY CLOSE INTO
AN UPPER LOW ON MONDAY. SEVERAL PIECES OF ENERGY ROTATING AROUND THE
LOW WILL BRING ADDITIONAL CHANCE FOR SHOWERS AND THUNDERSTORMS TO
THE AREA. THINKING THE BULK OF THE INSTABILITY SHOULD BE SOUTHEAST
OF THE FORECAST AREA SO IT APPEARS THE GREATEST SEVERE THREAT SHOULD
BE SOUTHEAST OF THE AREA...BUT THIS WILL DEPEND ON HOW THE
CONVECTION PLAYS OUT SUNDAY NIGHT. THE UPPER LOW CONTINUES TO SPIN
OVER THE REIGON THROUGH MIDWEEK WITH DAILY CHANCES FOR SHOWERS AND
POSSIBLE THUNDERSTORMS.

&&

.AVIATION...TODAY AND TONIGHT
1130 AM CDT FRI MAY 17 2013

SFC FRONT LAYING WEST-EAST ACROSS SOUTHERN MN/WESTERN WI CONTINUES
TO BE A FOCUS FOR SHRA/ISOLD TS DEVELOPMENT LATE THIS MORNING. NOT
MUCH-IF ANY INSTABILITY OR LOW LEVEL MOISTURE TRANSPORT INTO THE
FRONT THOUGH...PER MESO MODELS. INDICATIONS THAT THE PCPN IS GETTING
SOME ENHANCEMENT ON ITS WESTERN EDGES FROM AN UPPER LEVEL SHORTWAVE
TROUGH...PER LATEST WATER VAPOR SATELLITE IMAGERY. THIS FEATURE IS
MOVING EAST...AND NAM12/HRRR SUGGEST THAT THE PCPN WILL MOVE WITH
IT. WILL TREND THE TAFS THIS WAY. THE HRRR DOES HINT THAT THE FRONT
WON/T MOVE TOO FAR NORTH THIS EVENING...AND COULD SERVE AS A FOCUS
FOR MORE SCT SHRA/TS. ARXLAPS ALSO HAS THIS POTENTIAL...WEST OF THE
MISSISSIPPI RIVER. CONFIDENCE SHAKY ON THIS POSSIBILITY...AND WILL
LIKELY LEAVE OUT OF THE KRST TAF FOR NOW.

WITH THE PROLONGED PERIOD OF RAIN MOISTENING THE BOUNDARY LAYER FOR
KRST/KLSE...FOG/STRATUS BECOMES A CONCERN OVERNIGHT. KLSE LIKELY
DECOUPLES RESULTING IN LIGHT/VRB WINDS. KRST PROBABLY STICKS AROUND
6-8KTS FROM THE ESE. NUMERICAL GUIDANCE AND BUFKIT SOUNDINGS POINT
TO GOOD SATURATION UNDER THE NOCTURNAL INVERSION THAT VSBY
RESTRICTIONS ARE LIKELY...ALONG WITH LOW STRATUS. MVFR/IFR
CONDITIONS ARE FAVORED INTO SATURDAY MORNING.


&&

.HYDROLOGY...THIS EVENING THROUGH MONDAY
ISSUED AT 341 PM CDT FRI MAY 17 2013

PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF SOUTHEAST
MINNESOTA INTO NORTHEAST IOWA HAVE PRODUCED 2 TO NEARLY 2 1/2
INCHES OF RAINFALL SO FAR TODAY. SCATTERED THUNDERSTORMS ARE
EXPECTED LATE THIS AFTERNOON INTO EARLY THIS EVENING. THE STORMS
ARE SLOW MOVING AND WILL HAVE THE POTENTIAL TO PRODUCE PERIODS OF
HEAVY RAINFALL...WHICH COULD LEAD TO FLOODING...ESPECIALLY ACROSS
THOSE AREAS THAT HAVE ALREADY SEEN HEAVY RAINFALL.

THUNDERSTORMS ARE EXPECTED SUNDAY AFTERNOON THROUGH MONDAY. THE
STORMS COULD PRODUCE PERIODS OF HEAVY RAINFALL WHICH COULD LEAD TO
FLOODING. 1 TO 3 INCHES OF ADDITIOANL RAINFALL IS POSSIBLE FROM
SUNDAY INTO WEDNESDAY. A FLASH FLOOD WATCH MAY BE NEEDED IF
CONFIDENCE INCREASES ON WHERE THE HEAVIEST RAIN WILL FALL.

&&

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

$$

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

000
FXUS63 KARX 171635
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1130 AM CDT FRI MAY 17 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT FRI MAY 17 2013

FOCUS IS ON TRENDING CURRENT SHOWERS/STORMS ACROSS IA/MN...AND
CONVECTIVE PROBABILITIES LATER TODAY ALONG WARM FRONT.

LATEST RADAR SHOWS COMPLEX OF SHOWERS/STORMS ACROSS NORTHERN
IA/SOUTHERN MN...WHICH IS FEEDING OFF 850 MB LOW-LEVEL
JET...INTERACTING WITH A WARM FRONTAL BOUNDARY THAT STRETCHES ACROSS
NORTHERN IOWA. THESE STORMS ARE EFFICIENT HEAVY RAIN
PRODUCERS...GIVEN SLOW EASTWARD PROGRESS AND PWATS 1.4 TO 1.6
INCHES...WHICH IS 150 TO 180 PERCENT ABOVE NORMAL. THESE STORMS ARE
EXPECTED TO MOVE EASTWARD ACROSS SOUTHEAST MINNESOTA AND EXTREME
NORTHEAST IOWA...AND PARTS OF WESTERN WISCONSIN THROUGH MID/LATE
MORNING. SOME OF THE STRONGER CELLS COULD PRODUCE SMALL HAIL...BUT
NOT EXPECTING ANYTHING TO REACH SEVERE LIMITS. THE BIGGER IMPACT
WOULD BE LOCALIZED HEAVY RAINFALL...AND IN TOTAL...AMOUNTS BETWEEN 1
AND 2 INCHES ARE POSSIBLE.

THE BIG QUESTION FOR TODAY IS WHERE THE WARM FRONT ENDS UP...AND IF
ANOTHER ROUND OF SHOWERS/STORMS DEVELOPS ALONG IT THIS AFTERNOON.
LATEST RAP HAS A DECENT HANDLE RIGHT NOW...SHOWING THAT THE WARM
FRONT SETTLES ALONG THE IA/MN BORDER...AND INTO SOUTHWEST WISCONSIN
THIS AFTERNOON. ONGOING CONVECTION SHOULD KEEP NORTHWARD PROGRESS OF
THE BOUNDARY LIMITED SO RAP SOLUTION SEEMS REASONABLE. THE REMNANTS
OF THIS MORNING/S STORMS WOULD LIFT TO THE EAST/NORTHEAST...BUT
LEFTOVER OUTFLOW BOUNDARIES COMBINED WITH MODEST DAYTIME HEATING AND
A PASSING UPPER LEVEL SHORTWAVE LOOKS TO BE SUFFICIENT FOR
ADDITIONAL SHOWERS AND STORMS TO DEVELOP. THESE SHOWERS AGAIN
WOULD HAVE THE POTENTIAL TO PRODUCE HEAVY RAIN.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI MAY 17 2013

...SEVERE WEATHER EVENT POSSIBLE SUNDAY AND AGAIN ON MONDAY...

SATURDAY FEATURES UPPER LEVEL RIDGING ACROSS THE CENTRAL PLAINS AS
THE WEST COAST TROUGH CONTINUES TO MOVE EASTWARD. AT THE
SURFACE...LOW PRESSURE DEVELOPS IN THE LEE OF THE ROCKIES AND PUSHES
THE AFOREMENTIONED WARM FRONT WELL NORTH OF THE FORECAST AREA. THE
ATMOSPHERE BECOMES CAPPED FOR THE DAY...WITH THE WARM NOSE LAYER
EVIDENT IN THE 850 TO 750 MB LAYER. PLENTY OF ELEVATED CAPE NOTED
ACROSS THE AREA...ANYWHERE FROM 2000 TO 3000 J/KG BY SATURDAY
AFTERNOON. THE CAP REMAINS IN PLACE DURING THE DAY...BUT DOES WEAKEN
SOME BY LATE AFTERNOON AND EVENING AS CIN VALUES DROP TO LESS THAN
50 J/KG...MAINLY ALONG AND NORTH OF I-90. THE LACK OF A STRONG
FORCING MECHANISM SHOULD KEEP CONVECTIVE INITIATION PROBABILITIES
LOW...AND THIS IS WELL AGREED AMONG THE VARIOUS DETERMINISTIC
MODELS. THE ONLY EXCEPTION IS IN THE 17.00Z GFS WHERE A WEAK UPPER
LEVEL SHORTWAVE TROUGHS RIDES THE RIDGE ACROSS NORTHERN WISCONSIN.
THIS COULD PROVIDE ENOUGH UPPER LEVEL SUPPORT TO BREAK THE WEAKER
CAP AND ALLOW SHOWERS/STORMS TO INITIATE. HAVE CONTINUED CHANCE POPS
MAINLY NORTH OF I-90 TO HIGHLIGHT THIS IDEA. ANY STORM CAPABLE OF
BREAKING THROUGH THE CAP AND BECOMING SURFACE BASED HAS THE
POTENTIAL TO PRODUCE LARGE HAIL AND POSSIBLY DAMAGING WINDS GIVEN
THE INSTABILITY AND 0-6 KM BULK SHEAR NEAR 30 KTS. OTHERWISE...WARM
DAY ON TAP WITH HIGHS IN THE LOW TO MID 80S.

FOCUS TURNS TO THE POTENTIAL SEVERE WEATHER EVENT FOR SUNDAY AS THE
AFOREMENTIONED UPPER LEVEL TROUGH BECOMES INCREASINGLY NEGATIVE
TILTED AND EJECTS INTO THE CENTRAL PLAINS BY 12Z SUNDAY. THE BASE OF
THE TROUGH WILL LIKELY BE ACROSS OK/KS...BUT QUICKLY LIFTS NORTHEAST
TOWARD WESTERN IOWA BY 00Z MONDAY. AT THE SURFACE...LOW PRESSURE
LOOKS TO MOVE NORTHEASTWARD FROM NEBRASKA TO NEAR SIOUX FALLS
SD...AND A WARM FRONT SHOULD BE DRAPED ACROSS SOUTHWEST MINNESOTA
EAST/SOUTHEASTWARD INTO NORTHEAST IOWA. IT/S POSSIBLE THERE COULD BE
SOME DECAYING CONVECTION SUNDAY MORNING ACROSS WESTERN IOWA...AND
THIS COULD PLAY INTO HOW UNSTABLE THE ATMOSPHERE BECOMES LATER THAT
DAY ACROSS THE REGION. IN ANY RATE...MUCAPE VALUES ARE EXPECTED TO
RANGE 3000 TO 3500 J/KG AND 0-6 KM BULK SHEAR VALUES APPROACH 35 KTS
WEST OF THE MISSISSIPPI RIVER SUNDAY AFTERNOON AND EVENING. THE
MAJORITY OF THE SHEAR IS FOUND IN THE 0-3 KM LAYER WITH 25 KTS SEEN.
EVEN MORE EXCITING ARE THE 0-1 KM SHEAR PARAMETERS...WHICH IS AT
LEAST 20 KTS. FINALLY...THE AIRMASS ACROSS SOUTHEAST MINNESOTA AND
NORTHERN IOWA SUNDAY LOOKS TO BE SOMEWHAT JUICY WITH DEWPOINTS IN
THE 60S. HOW JUICY IS STILL A QUESTION GIVEN DETERMINISTIC MODELS
POOR HANDLING OF DEWPOINTS LATELY. 17.00Z NAM/GFS PUT UPPER 60S TO
EVEN NEAR 70F BY 21Z SUNDAY...WHICH SEEMS A BIT OVERDONE. ADJUSTING
SOUNDINGS TO WHAT COULD BE A MORE REALISTIC VALUE /LOW TO MID 60S/
BASED ON THE MOIST BIAS STILL YIELDS CAPE VALUES IN THE 1500 TO 2500
J/KG RANGE.

IN SHORT...ENVISION STORMS TO FIRE UP ACROSS CENTRAL IOWA INTO
SOUTHERN MINNESOTA BY EARLY AFTERNOON SUNDAY...THEN QUICK MOVE
EAST/NORTHEAST...LASTING INTO THE EVENING HOURS. THE HIGHER SEVERE
CHANCES ARE WEST OF THE MISSISSIPPI RIVER...AS STORMS WOULD WEAKEN
SOME MOVING INTO WISCONSIN BUT STILL COULD REMAIN SEVERE. ORGANIZED
DISCRETE STRONG/SEVERE STORMS WOULD BE THE PRIMARY MODE...MAINLY
SUPERCELLS...WITH A PREFERENCE TO THE RIGHT MOVERS GIVEN CLOCKWISE
CURVATURE SEEN IN THE HODOGRAPHS. THE MAIN THREATS LOOK TO BE VERY
LARGE HAIL AND DAMAGING WINDS BUT ALSO A FAVORABLE ENVIRONMENT FOR
TORNADOES GIVEN 0-1 KM BULK SHEAR /AT LEAST 20 KTS/ AND EHI /1.0 TO
3.0/. WILL HIGHLIGHT INCREASED THREAT ACROSS THE MANY PUBLIC
PRODUCTS /HWO...GRAPHICAST...NEWS STORY/. THOSE WITH PLANS SUNDAY
AFTERNOON/EVENING WILL NEED TO KEEP A VERY CLOSE EYE TO THE FORECAST.

ANOTHER ROUND OF STRONG/SEVERE STORMS IS POSSIBLE MONDAY EVENING AS
THE WHOLE SYSTEM SLOWLY EDGES EASTWARD. ANOTHER FAVORABLE SEVERE
WEATHER ENVIRONMENT WITH 0-6 KM MUCAPE PEGGED BETWEEN 2000 TO
3000 J/KG AND BULK SHEAR 30 TO 40 KTS. DEPENDING ON HOW MUCH
EASTWARD PROGRESSION OF THE WEATHER SYSTEM OCCURS MONDAY...A
GREATER PERCENTAGE OF THE FORECAST AREA COULD BE IN RISK FOR
SEVERE WEATHER. AT THIS TIME...HIGHER THREAT AREA LOOKS TO BE
ALONG AND SOUTH OF I-90.

MODEL TIMING DIFFERENCES CREEP UP BY TUESDAY...MAINLY IN HOW QUICKLY
THE UPPER LEVEL CLOSES OFF AND MOVES EAST OVER THE AREA. WIDE RANGE
OF POSSIBILITIES ON WHEN THE LOW MOVES OVERHEAD...WITH THE 17.00Z
GFS THE QUICKEST /TUESDAY/ AND THE ECMWF SLOWEST /WEDNESDAY/. FOR
NOW...PERIODIC SHOWERS/STORMS TUESDAY AND WEDNESDAY LOOK GOOD.
COOLER TEMPERATURES ALOFT AND THREAT OF SHOWERS SHOULD KEEP HIGHS ON
THE COOLER SIDE WEDNESDAY AND THURSDAY...5 TO 7 DEGREES BELOW
NORMALS.

&&

.AVIATION...TODAY AND TONIGHT
1130 AM CDT FRI MAY 17 2013

SFC FRONT LAYING WEST-EAST ACROSS SOUTHERN MN/WESTERN WI CONTINUES
TO BE A FOCUS FOR SHRA/ISOLD TS DEVELOPMENT LATE THIS MORNING. NOT
MUCH-IF ANY INSTABILITY OR LOW LEVEL MOISTURE TRANSPORT INTO THE
FRONT THOUGH...PER MESO MODELS. INDICATIONS THAT THE PCPN IS GETTING
SOME ENHANCEMENT ON ITS WESTERN EDGES FROM AN UPPER LEVEL SHORTWAVE
TROUGH...PER LATEST WATER VAPOR SATELLITE IMAGERY. THIS FEATURE IS
MOVING EAST...AND NAM12/HRRR SUGGEST THAT THE PCPN WILL MOVE WITH
IT. WILL TREND THE TAFS THIS WAY. THE HRRR DOES HINT THAT THE FRONT
WON/T MOVE TOO FAR NORTH THIS EVENING...AND COULD SERVE AS A FOCUS
FOR MORE SCT SHRA/TS. ARXLAPS ALSO HAS THIS POTENTIAL...WEST OF THE
MISSISSIPPI RIVER. CONFIDENCE SHAKY ON THIS POSSIBILITY...AND WILL
LIKELY LEAVE OUT OF THE KRST TAF FOR NOW.

WITH THE PROLONGED PERIOD OF RAIN MOISTENING THE BOUNDARY LAYER FOR
KRST/KLSE...FOG/STRATUS BECOMES A CONCERN OVERNIGHT. KLSE LIKELY
DECOUPLES RESULTING IN LIGHT/VRB WINDS. KRST PROBABLY STICKS AROUND
6-8KTS FROM THE ESE. NUMERICAL GUIDANCE AND BUFKIT SOUNDINGS POINT
TO GOOD SATURATION UNDER THE NOCTURNAL INVERSION THAT VSBY
RESTRICTIONS ARE LIKELY...ALONG WITH LOW STRATUS. MVFR/IFR
CONDITIONS ARE FAVORED INTO SATURDAY MORNING.

&&

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

&&

$$

SHORT TERM...ZT
LONG TERM....ZT
AVIATION.....RIECK

000
FXUS63 KARX 171218
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
718 AM CDT FRI MAY 17 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT FRI MAY 17 2013

FOCUS IS ON TRENDING CURRENT SHOWERS/STORMS ACROSS IA/MN...AND
CONVECTIVE PROBABILITIES LATER TODAY ALONG WARM FRONT.

LATEST RADAR SHOWS COMPLEX OF SHOWERS/STORMS ACROSS NORTHERN
IA/SOUTHERN MN...WHICH IS FEEDING OFF 850 MB LOW-LEVEL
JET...INTERACTING WITH A WARM FRONTAL BOUNDARY THAT STRETCHES ACROSS
NORTHERN IOWA. THESE STORMS ARE EFFICIENT HEAVY RAIN
PRODUCERS...GIVEN SLOW EASTWARD PROGRESS AND PWATS 1.4 TO 1.6
INCHES...WHICH IS 150 TO 180 PERCENT ABOVE NORMAL. THESE STORMS ARE
EXPECTED TO MOVE EASTWARD ACROSS SOUTHEAST MINNESOTA AND EXTREME
NORTHEAST IOWA...AND PARTS OF WESTERN WISCONSIN THROUGH MID/LATE
MORNING. SOME OF THE STRONGER CELLS COULD PRODUCE SMALL HAIL...BUT
NOT EXPECTING ANYTHING TO REACH SEVERE LIMITS. THE BIGGER IMPACT
WOULD BE LOCALIZED HEAVY RAINFALL...AND IN TOTAL...AMOUNTS BETWEEN 1
AND 2 INCHES ARE POSSIBLE.

THE BIG QUESTION FOR TODAY IS WHERE THE WARM FRONT ENDS UP...AND IF
ANOTHER ROUND OF SHOWERS/STORMS DEVELOPS ALONG IT THIS AFTERNOON.
LATEST RAP HAS A DECENT HANDLE RIGHT NOW...SHOWING THAT THE WARM
FRONT SETTLES ALONG THE IA/MN BORDER...AND INTO SOUTHWEST WISCONSIN
THIS AFTERNOON. ONGOING CONVECTION SHOULD KEEP NORTHWARD PROGRESS OF
THE BOUNDARY LIMITED SO RAP SOLUTION SEEMS REASONABLE. THE REMNANTS
OF THIS MORNING/S STORMS WOULD LIFT TO THE EAST/NORTHEAST...BUT
LEFTOVER OUTFLOW BOUNDARIES COMBINED WITH MODEST DAYTIME HEATING AND
A PASSING UPPER LEVEL SHORTWAVE LOOKS TO BE SUFFICIENT FOR
ADDITIONAL SHOWERS AND STORMS TO DEVELOP. THESE SHOWERS AGAIN
WOULD HAVE THE POTENTIAL TO PRODUCE HEAVY RAIN.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI MAY 17 2013

...SEVERE WEATHER EVENT POSSIBLE SUNDAY AND AGAIN ON MONDAY...

SATURDAY FEATURES UPPER LEVEL RIDGING ACROSS THE CENTRAL PLAINS AS
THE WEST COAST TROUGH CONTINUES TO MOVE EASTWARD. AT THE
SURFACE...LOW PRESSURE DEVELOPS IN THE LEE OF THE ROCKIES AND PUSHES
THE AFOREMENTIONED WARM FRONT WELL NORTH OF THE FORECAST AREA. THE
ATMOSPHERE BECOMES CAPPED FOR THE DAY...WITH THE WARM NOSE LAYER
EVIDENT IN THE 850 TO 750 MB LAYER. PLENTY OF ELEVATED CAPE NOTED
ACROSS THE AREA...ANYWHERE FROM 2000 TO 3000 J/KG BY SATURDAY
AFTERNOON. THE CAP REMAINS IN PLACE DURING THE DAY...BUT DOES WEAKEN
SOME BY LATE AFTERNOON AND EVENING AS CIN VALUES DROP TO LESS THAN
50 J/KG...MAINLY ALONG AND NORTH OF I-90. THE LACK OF A STRONG
FORCING MECHANISM SHOULD KEEP CONVECTIVE INITIATION PROBABILITIES
LOW...AND THIS IS WELL AGREED AMONG THE VARIOUS DETERMINISTIC
MODELS. THE ONLY EXCEPTION IS IN THE 17.00Z GFS WHERE A WEAK UPPER
LEVEL SHORTWAVE TROUGHS RIDES THE RIDGE ACROSS NORTHERN WISCONSIN.
THIS COULD PROVIDE ENOUGH UPPER LEVEL SUPPORT TO BREAK THE WEAKER
CAP AND ALLOW SHOWERS/STORMS TO INITIATE. HAVE CONTINUED CHANCE POPS
MAINLY NORTH OF I-90 TO HIGHLIGHT THIS IDEA. ANY STORM CAPABLE OF
BREAKING THROUGH THE CAP AND BECOMING SURFACE BASED HAS THE
POTENTIAL TO PRODUCE LARGE HAIL AND POSSIBLY DAMAGING WINDS GIVEN
THE INSTABILITY AND 0-6 KM BULK SHEAR NEAR 30 KTS. OTHERWISE...WARM
DAY ON TAP WITH HIGHS IN THE LOW TO MID 80S.

FOCUS TURNS TO THE POTENTIAL SEVERE WEATHER EVENT FOR SUNDAY AS THE
AFOREMENTIONED UPPER LEVEL TROUGH BECOMES INCREASINGLY NEGATIVE
TILTED AND EJECTS INTO THE CENTRAL PLAINS BY 12Z SUNDAY. THE BASE OF
THE TROUGH WILL LIKELY BE ACROSS OK/KS...BUT QUICKLY LIFTS NORTHEAST
TOWARD WESTERN IOWA BY 00Z MONDAY. AT THE SURFACE...LOW PRESSURE
LOOKS TO MOVE NORTHEASTWARD FROM NEBRASKA TO NEAR SIOUX FALLS
SD...AND A WARM FRONT SHOULD BE DRAPED ACROSS SOUTHWEST MINNESOTA
EAST/SOUTHEASTWARD INTO NORTHEAST IOWA. IT/S POSSIBLE THERE COULD BE
SOME DECAYING CONVECTION SUNDAY MORNING ACROSS WESTERN IOWA...AND
THIS COULD PLAY INTO HOW UNSTABLE THE ATMOSPHERE BECOMES LATER THAT
DAY ACROSS THE REGION. IN ANY RATE...MUCAPE VALUES ARE EXPECTED TO
RANGE 3000 TO 3500 J/KG AND 0-6 KM BULK SHEAR VALUES APPROACH 35 KTS
WEST OF THE MISSISSIPPI RIVER SUNDAY AFTERNOON AND EVENING. THE
MAJORITY OF THE SHEAR IS FOUND IN THE 0-3 KM LAYER WITH 25 KTS SEEN.
EVEN MORE EXCITING ARE THE 0-1 KM SHEAR PARAMETERS...WHICH IS AT
LEAST 20 KTS. FINALLY...THE AIRMASS ACROSS SOUTHEAST MINNESOTA AND
NORTHERN IOWA SUNDAY LOOKS TO BE SOMEWHAT JUICY WITH DEWPOINTS IN
THE 60S. HOW JUICY IS STILL A QUESTION GIVEN DETERMINISTIC MODELS
POOR HANDLING OF DEWPOINTS LATELY. 17.00Z NAM/GFS PUT UPPER 60S TO
EVEN NEAR 70F BY 21Z SUNDAY...WHICH SEEMS A BIT OVERDONE. ADJUSTING
SOUNDINGS TO WHAT COULD BE A MORE REALISTIC VALUE /LOW TO MID 60S/
BASED ON THE MOIST BIAS STILL YIELDS CAPE VALUES IN THE 1500 TO 2500
J/KG RANGE.

IN SHORT...ENVISION STORMS TO FIRE UP ACROSS CENTRAL IOWA INTO
SOUTHERN MINNESOTA BY EARLY AFTERNOON SUNDAY...THEN QUICK MOVE
EAST/NORTHEAST...LASTING INTO THE EVENING HOURS. THE HIGHER SEVERE
CHANCES ARE WEST OF THE MISSISSIPPI RIVER...AS STORMS WOULD WEAKEN
SOME MOVING INTO WISCONSIN BUT STILL COULD REMAIN SEVERE. ORGANIZED
DISCRETE STRONG/SEVERE STORMS WOULD BE THE PRIMARY MODE...MAINLY
SUPERCELLS...WITH A PREFERENCE TO THE RIGHT MOVERS GIVEN CLOCKWISE
CURVATURE SEEN IN THE HODOGRAPHS. THE MAIN THREATS LOOK TO BE VERY
LARGE HAIL AND DAMAGING WINDS BUT ALSO A FAVORABLE ENVIRONMENT FOR
TORNADOES GIVEN 0-1 KM BULK SHEAR /AT LEAST 20 KTS/ AND EHI /1.0 TO
3.0/. WILL HIGHLIGHT INCREASED THREAT ACROSS THE MANY PUBLIC
PRODUCTS /HWO...GRAPHICAST...NEWS STORY/. THOSE WITH PLANS SUNDAY
AFTERNOON/EVENING WILL NEED TO KEEP A VERY CLOSE EYE TO THE FORECAST.

ANOTHER ROUND OF STRONG/SEVERE STORMS IS POSSIBLE MONDAY EVENING AS
THE WHOLE SYSTEM SLOWLY EDGES EASTWARD. ANOTHER FAVORABLE SEVERE
WEATHER ENVIRONMENT WITH 0-6 KM MUCAPE PEGGED BETWEEN 2000 TO
3000 J/KG AND BULK SHEAR 30 TO 40 KTS. DEPENDING ON HOW MUCH
EASTWARD PROGRESSION OF THE WEATHER SYSTEM OCCURS MONDAY...A
GREATER PERCENTAGE OF THE FORECAST AREA COULD BE IN RISK FOR
SEVERE WEATHER. AT THIS TIME...HIGHER THREAT AREA LOOKS TO BE
ALONG AND SOUTH OF I-90.

MODEL TIMING DIFFERENCES CREEP UP BY TUESDAY...MAINLY IN HOW QUICKLY
THE UPPER LEVEL CLOSES OFF AND MOVES EAST OVER THE AREA. WIDE RANGE
OF POSSIBILITIES ON WHEN THE LOW MOVES OVERHEAD...WITH THE 17.00Z GFS
THE QUICKEST /TUESDAY/ AND THE ECMWF SLOWEST /WEDNESDAY/. FOR
NOW...PERIODIC SHOWERS/STORMS TUESDAY AND WEDNESDAY LOOK GOOD.
COOLER TEMPERATURES ALOFT AND THREAT OF SHOWERS SHOULD KEEP HIGHS ON
THE COOLER SIDE WEDNESDAY AND THURSDAY...5 TO 7 DEGREES BELOW
NORMALS.

&&

.AVIATION...TODAY AND TONIGHT
715 AM CDT FRI MAY 17 2013

BROAD SHIELD OF RAIN MOVING THROUGH THE TAF SITES EARLY THIS
MORNING. SOME MVFR CEILINGS AND VISIBILITY FOR A TIME...BUT
EXPECTING THE RAIN TO LET UP AND CONDITIONS TO IMPROVE BY MID
TO LATE MORNING. QUESTION THEN BECOMES ANY NEW CONVECTIVE
DEVELOPMENT FOR THE AFTERNOON. SOME OF THE MESOSCALE MODELS ARE
INDICATING SOME NEW DEVELOPMENT AS THE WARM FRONT PUSHES NORTHWARD
AND THE UPPER TROUGH EDGES EVER CLOSER. AT THIS POINT IT IS
LOOKING LIKE ANY REDEVELOPMENT WILL BE SPOTTY...AND MAY MISS THE
TAF SITES ALTOGETHER. THUS DID NOT INCLUDE IN THE 12Z VERSION.
WINDS SLACKEN TONIGHT...AND WITH A MOIST BOUNDARY LATER DUE TO
RAIN TODAY AND INCREASING MOIST ADVECTION...EXPECT FOG COULD
BECOME AN ISSUE. AT THIS POINT ADDED SOME MVFR FOG RESTRICTIONS
TO THE TAFS AFTER 08Z.

&&

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

&&

$$

SHORT TERM...ZT
LONG TERM...ZT
AVIATION...MW

000
FXUS63 KARX 170850
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
350 AM CDT FRI MAY 17 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT FRI MAY 17 2013

FOCUS IS ON TRENDING CURRENT SHOWERS/STORMS ACROSS IA/MN...AND
CONVECTIVE PROBABILITIES LATER TODAY ALONG WARM FRONT.

LATEST RADAR SHOWS COMPLEX OF SHOWERS/STORMS ACROSS NORTHERN
IA/SOUTHERN MN...WHICH IS FEEDING OFF 850 MB LOW-LEVEL
JET...INTERACTING WITH A WARM FRONTAL BOUNDARY THAT STRETCHES ACROSS
NORTHERN IOWA. THESE STORMS ARE EFFICIENT HEAVY RAIN
PRODUCERS...GIVEN SLOW EASTWARD PROGRESS AND PWATS 1.4 TO 1.6
INCHES...WHICH IS 150 TO 180 PERCENT ABOVE NORMAL. THESE STORMS ARE
EXPECTED TO MOVE EASTWARD ACROSS SOUTHEAST MINNESOTA AND EXTREME
NORTHEAST IOWA...AND PARTS OF WESTERN WISCONSIN THROUGH MID/LATE
MORNING. SOME OF THE STRONGER CELLS COULD PRODUCE SMALL HAIL...BUT
NOT EXPECTING ANYTHING TO REACH SEVERE LIMITS. THE BIGGER IMPACT
WOULD BE LOCALIZED HEAVY RAINFALL...AND IN TOTAL...AMOUNTS BETWEEN 1
AND 2 INCHES ARE POSSIBLE.

THE BIG QUESTION FOR TODAY IS WHERE THE WARM FRONT ENDS UP...AND IF
ANOTHER ROUND OF SHOWERS/STORMS DEVELOPS ALONG IT THIS AFTERNOON.
LATEST RAP HAS A DECENT HANDLE RIGHT NOW...SHOWING THAT THE WARM
FRONT SETTLES ALONG THE IA/MN BORDER...AND INTO SOUTHWEST WISCONSIN
THIS AFTERNOON. ONGOING CONVECTION SHOULD KEEP NORTHWARD PROGRESS OF
THE BOUNDARY LIMITED SO RAP SOLUTION SEEMS REASONABLE. THE REMNANTS
OF THIS MORNING/S STORMS WOULD LIFT TO THE EAST/NORTHEAST...BUT
LEFTOVER OUTFLOW BOUNDARIES COMBINED WITH MODEST DAYTIME HEATING AND
A PASSING UPPER LEVEL SHORTWAVE LOOKS TO BE SUFFICIENT FOR
ADDITIONAL SHOWERS AND STORMS TO DEVELOP. THESE SHOWERS AGAIN
WOULD HAVE THE POTENTIAL TO PRODUCE HEAVY RAIN.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI MAY 17 2013

...SEVERE WEATHER EVENT POSSIBLE SUNDAY AND AGAIN ON MONDAY...

SATURDAY FEATURES UPPER LEVEL RIDGING ACROSS THE CENTRAL PLAINS AS
THE WEST COAST TROUGH CONTINUES TO MOVE EASTWARD. AT THE
SURFACE...LOW PRESSURE DEVELOPS IN THE LEE OF THE ROCKIES AND PUSHES
THE AFOREMENTIONED WARM FRONT WELL NORTH OF THE FORECAST AREA. THE
ATMOSPHERE BECOMES CAPPED FOR THE DAY...WITH THE WARM NOSE LAYER
EVIDENT IN THE 850 TO 750 MB LAYER. PLENTY OF ELEVATED CAPE NOTED
ACROSS THE AREA...ANYWHERE FROM 2000 TO 3000 J/KG BY SATURDAY
AFTERNOON. THE CAP REMAINS IN PLACE DURING THE DAY...BUT DOES WEAKEN
SOME BY LATE AFTERNOON AND EVENING AS CIN VALUES DROP TO LESS THAN
50 J/KG...MAINLY ALONG AND NORTH OF I-90. THE LACK OF A STRONG
FORCING MECHANISM SHOULD KEEP CONVECTIVE INITIATION PROBABILITIES
LOW...AND THIS IS WELL AGREED AMONG THE VARIOUS DETERMINISTIC
MODELS. THE ONLY EXCEPTION IS IN THE 17.00Z GFS WHERE A WEAK UPPER
LEVEL SHORTWAVE TROUGHS RIDES THE RIDGE ACROSS NORTHERN WISCONSIN.
THIS COULD PROVIDE ENOUGH UPPER LEVEL SUPPORT TO BREAK THE WEAKER
CAP AND ALLOW SHOWERS/STORMS TO INITIATE. HAVE CONTINUED CHANCE POPS
MAINLY NORTH OF I-90 TO HIGHLIGHT THIS IDEA. ANY STORM CAPABLE OF
BREAKING THROUGH THE CAP AND BECOMING SURFACE BASED HAS THE
POTENTIAL TO PRODUCE LARGE HAIL AND POSSIBLY DAMAGING WINDS GIVEN
THE INSTABILITY AND 0-6 KM BULK SHEAR NEAR 30 KTS. OTHERWISE...WARM
DAY ON TAP WITH HIGHS IN THE LOW TO MID 80S.

FOCUS TURNS TO THE POTENTIAL SEVERE WEATHER EVENT FOR SUNDAY AS THE
AFOREMENTIONED UPPER LEVEL TROUGH BECOMES INCREASINGLY NEGATIVE
TILTED AND EJECTS INTO THE CENTRAL PLAINS BY 12Z SUNDAY. THE BASE OF
THE TROUGH WILL LIKELY BE ACROSS OK/KS...BUT QUICKLY LIFTS NORTHEAST
TOWARD WESTERN IOWA BY 00Z MONDAY. AT THE SURFACE...LOW PRESSURE
LOOKS TO MOVE NORTHEASTWARD FROM NEBRASKA TO NEAR SIOUX FALLS
SD...AND A WARM FRONT SHOULD BE DRAPED ACROSS SOUTHWEST MINNESOTA
EAST/SOUTHEASTWARD INTO NORTHEAST IOWA. IT/S POSSIBLE THERE COULD BE
SOME DECAYING CONVECTION SUNDAY MORNING ACROSS WESTERN IOWA...AND
THIS COULD PLAY INTO HOW UNSTABLE THE ATMOSPHERE BECOMES LATER THAT
DAY ACROSS THE REGION. IN ANY RATE...MUCAPE VALUES ARE EXPECTED TO
RANGE 3000 TO 3500 J/KG AND 0-6 KM BULK SHEAR VALUES APPROACH 35 KTS
WEST OF THE MISSISSIPPI RIVER SUNDAY AFTERNOON AND EVENING. THE
MAJORITY OF THE SHEAR IS FOUND IN THE 0-3 KM LAYER WITH 25 KTS SEEN.
EVEN MORE EXCITING ARE THE 0-1 KM SHEAR PARAMETERS...WHICH IS AT
LEAST 20 KTS. FINALLY...THE AIRMASS ACROSS SOUTHEAST MINNESOTA AND
NORTHERN IOWA SUNDAY LOOKS TO BE SOMEWHAT JUICY WITH DEWPOINTS IN
THE 60S. HOW JUICY IS STILL A QUESTION GIVEN DETERMINISTIC MODELS
POOR HANDLING OF DEWPOINTS LATELY. 17.00Z NAM/GFS PUT UPPER 60S TO
EVEN NEAR 70F BY 21Z SUNDAY...WHICH SEEMS A BIT OVERDONE. ADJUSTING
SOUNDINGS TO WHAT COULD BE A MORE REALISTIC VALUE /LOW TO MID 60S/
BASED ON THE MOIST BIAS STILL YIELDS CAPE VALUES IN THE 1500 TO 2500
J/KG RANGE.

IN SHORT...ENVISION STORMS TO FIRE UP ACROSS CENTRAL IOWA INTO
SOUTHERN MINNESOTA BY EARLY AFTERNOON SUNDAY...THEN QUICK MOVE
EAST/NORTHEAST...LASTING INTO THE EVENING HOURS. THE HIGHER SEVERE
CHANCES ARE WEST OF THE MISSISSIPPI RIVER...AS STORMS WOULD WEAKEN
SOME MOVING INTO WISCONSIN BUT STILL COULD REMAIN SEVERE. ORGANIZED
DISCRETE STRONG/SEVERE STORMS WOULD BE THE PRIMARY MODE...MAINLY
SUPERCELLS...WITH A PREFERENCE TO THE RIGHT MOVERS GIVEN CLOCKWISE
CURVATURE SEEN IN THE HODOGRAPHS. THE MAIN THREATS LOOK TO BE VERY
LARGE HAIL AND DAMAGING WINDS BUT ALSO A FAVORABLE ENVIRONMENT FOR
TORNADOES GIVEN 0-1 KM BULK SHEAR /AT LEAST 20 KTS/ AND EHI /1.0 TO
3.0/. WILL HIGHLIGHT INCREASED THREAT ACROSS THE MANY PUBLIC
PRODUCTS /HWO...GRAPHICAST...NEWS STORY/. THOSE WITH PLANS SUNDAY
AFTERNOON/EVENING WILL NEED TO KEEP A VERY CLOSE EYE TO THE FORECAST.

ANOTHER ROUND OF STRONG/SEVERE STORMS IS POSSIBLE MONDAY EVENING AS
THE WHOLE SYSTEM SLOWLY EDGES EASTWARD. ANOTHER FAVORABLE SEVERE
WEATHER ENVIRONMENT WITH 0-6 KM MUCAPE PEGGED BETWEEN 2000 TO
3000 J/KG AND BULK SHEAR 30 TO 40 KTS. DEPENDING ON HOW MUCH
EASTWARD PROGRESSION OF THE WEATHER SYSTEM OCCURS MONDAY...A
GREATER PERCENTAGE OF THE FORECAST AREA COULD BE IN RISK FOR
SEVERE WEATHER. AT THIS TIME...HIGHER THREAT AREA LOOKS TO BE
ALONG AND SOUTH OF I-90.

MODEL TIMING DIFFERENCES CREEP UP BY TUESDAY...MAINLY IN HOW QUICKLY
THE UPPER LEVEL CLOSES OFF AND MOVES EAST OVER THE AREA. WIDE RANGE
OF POSSIBILITIES ON WHEN THE LOW MOVES OVERHEAD...WITH THE 17.00Z GFS
THE QUICKEST /TUESDAY/ AND THE ECMWF SLOWEST /WEDNESDAY/. FOR
NOW...PERIODIC SHOWERS/STORMS TUESDAY AND WEDNESDAY LOOK GOOD.
COOLER TEMPERATURES ALOFT AND THREAT OF SHOWERS SHOULD KEEP HIGHS ON
THE COOLER SIDE WEDNESDAY AND THURSDAY...5 TO 7 DEGREES BELOW
NORMALS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1150 PM CDT THU MAY 16 2013

COMPLEX OF STORMS THAT DEVELOPED THIS AFTERNOON OVER NORTHWEST
IOWA HAS BEEN STEADILY ADVANCING EAST TOWARD THE AREA AND
WEAKENING THIS EVENING. STILL SOME SHOWERS AND ISOLATED
THUNDERSTORMS LEFT WITH MOST OBSERVATIONS REPORTING JUST SOME
SPRINKLES FALLING OUT OF A MID LEVEL DECK. THE HRRR THIS EVENING
SEEMS TO HAVE THE BEST HANDLE ON HOW THINGS ARE PLAYING OUT AND
INDICATES THESE SHOWERS WILL MAKE IT INTO KRST BUT MAY FALL APART
BEFORE REACHING KLSE. WILL THUS SHOW A CATEGORICAL SHOWER AT KRST
WITH NO VISIBILITY RESTRICTION AND ONLY A VCSH AT KLSE. THE OTHER
CONCERN FOR TONIGHT IS WHAT THE TRAILING CONVECTION ACROSS
SOUTHWEST MINNESOTA AND NORTHWEST IOWA WILL DO. THE 17.03Z RAP ONLY
SHOWS SOME WEAK MOISTURE TRANSPORT INTO THIS ACTIVITY AND THE HRRR
WHILE HOLDING THIS TOGETHER...FOR THE MOST PART TAKES IT NORTH OF
BOTH TAF SITES. WILL NOT GET FANCY WITH THIS WITH JUST VFR
CONDITIONS EXPECTED AND WILL HOLD THE CATEGORICAL LIGHT SHOWERS AT
KRST THROUGH THE NIGHT EVEN THOUGH IT WILL NOT RAIN THAT LONG AND
KEEP AT VCSH AT KLSE INTO FRIDAY MORNING. THE NEXT CONCERN IS WITH
THE WARM FRONT THAT CUTS ACROSS IOWA. THIS SHOULD LIFT NORTH TOWARD
THE AREA FRIDAY AFTERNOON. STILL SOME CONCERN THAT CONVECTION
COULD DEVELOP ALONG THIS BUT CONFIDENCE STILL NOT HIGH ENOUGH TO
INCLUDE IN THE FORECAST AND WILL JUST SHOW SOME LOWER LEVEL
CUMULUS CLOUDS FOR THE AFTERNOON AND EVENING.


&&

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

$$

SHORT TERM...ZT
LONG TERM...ZT
AVIATION...04

000
FXUS63 KARX 170450
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1150 PM CDT THU MAY 16 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

WEAK HIGH PRESSURE WAS PROVIDING DRY AND QUIET WEATHER ACROSS THE
FORECAST AREA LATE THIS AFTERNOON. MEANWHILE...A SHORTWAVE WAS
MOVING ACROSS WESTERN/CENTRAL NEBRASKA GENERATING SHOWERS AND
THUNDERSTORMS ACROSS THESE AREAS. A WARM FRONT WAS SITUATED FROM
NORTHEAST NEBRASKA STRETCHING SOUTHEAST INTO SOUTH CENTRAL IOWA
THROUGH CENTRAL ILLINOIS. THE WAVE WILL PUSH EAST TONIGHT WITH
SHOWERS AND THUNDERSTORMS SPREADING INTO SOUTHWEST MINNESOTA AND
NORTHWEST IOWA LATE THIS AFTERNOON INTO THIS EVENING. THE WAVE IS
EXPECTED TO SLIDE ACROSS NORTHERN IOWA/SOUTHERN MINNESOTA LATE
TONIGHT...EDGING INTO THE FORECAST AREA AFTER MIDNIGHT TONIGHT.
LOCATIONS WEST OF HIGHWAY 52 WILL SEE THIS ACTIVITY MOVE IN BETWEEN
MIDNIGHT AND 3AM...THEN IT WILL SPREAD EAST TO ALONG THE MISSISSIPPI
RIVER AROUND SUNRISE. 850 MB MOISTURE TRANSPORT FOCUSES MAINLY ALONG
AND NORTH OF THE INTERSTATE 90 CORRIDOR FRIDAY MORNING INTO EARLY
FRIDAY AFTERNOON. FORECAST MODELS ARE SUGGESTING A MORE NORTHERLY
TRACK WITH THE CLUSTER OF SHOWERS AND STORMS SO HAVE INCREASED
PRECIPITATION CHANCES ACROSS SOUTHEAST MINNESOTA THROUGH NORTH
CENTRAL WISCONSIN. THE WARM FRONT IS EXPECTED LIFT NORTH SLIGHTLY ON
FRIDAY AS A POTENT TROUGH DIGS INTO THE SOUTHWEST CONUS AND SURFACE
LOW PRESSURE DEEPENS OVER THE HIGH PLAINS. BY LATE FRIDAY AFTERNOON
THE FRONT IS EXPECTED TO STRETCH FROM FAR SOUTHWEST WISCONSIN
THROUGH SOUTHERN MINNESOTA. THE CLUSTER OF SHOWERS AND STORMS TO
WEAKEN AND PUSH NORTHEAST OF THE AREA DURING THE LATE AFTERNOON.
HOWEVER...MESOSCALE MODELS....SUCH AS THE ARW...NMM...AND SPC WRF
GENERATE SHOWERS AND STORMS ALONG THE FRONT AS IT LIFTS NORTH INTO
THE UPPER MISSISSIPPI RIVER VALLEY. 0-3 KM MUCAPE VALUES CLIMB TO
1500 J/KG. GUIDANCE SUGGESTS THAT DEWPOINTS CLIMB INTO HE LOWER
60S RIGHT ALONG AND BEHIND THE WARM FRONT. THIS SEEMS REASONABLE
LOOKING AT DEWPOINTS BEHIND THE FRONT THIS AFTERNOON WHERE
DEWPOINTS HAVE CLIMBED INTO THE LOWER TO MID 60S. 0-6 KM BULK
SHEAR VALUES APPROACH 30 KTS ACROSS NORTHEAST IOWA...SOUTHEAST
MINNESOTA AND PORTIONS OF SOUTHWEST WISCONSIN. IF STORMS DEVELOP
FRIDAY AFTERNOON NEAR THE WARM FRONT...CANNOT RULE OUT AN ISOLATED
SEVERE STORM. THE MAIN HAZARD WOULD BE LARGE HAIL. HIGH
TEMPERATURES ON FRIDAY WILL RANGE FROM THE UPPER 50S TO AROUND 60
ACROSS FAR NORTHERN WISCONSIN TO THE MID TO UPPER 70S OVER PORTIONS
OF NORTHEAST IOWA.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

THE WARM FRONT IS EXPECTED TO DRIFT NORTHWARD FRIDAY NIGHT THROUGH
EARLY SATURDAY MORNING AS A VIGOROUS TROUGH DIGS INTO HE CENTRAL
PLAINS. RIDGING DEVELOPS OVER THE UPPER MISSISSIPPI RIVER VALLEY
FRIDAY NIGHT INTO SATURDAY MORNING AS MOIST...WARM AIR FLOWS INTO
THE FORECAST AREA IN THE WAKE OF THE FRONT. ONCE THE WARM FRONT
LIFTS NORTH OF THE AREA AND RIDGING MOVES IN THERE IS VERY LITTLE
FORCING TO WORK WITH WITHIN THE WARM SECTOR AND WARMER AIR MOVES IN
AT 850 MB...WITH CAPPING HOLDING STRONG THROUGH MUCH OF THE DAY.
DECIDED TO INCREASE HIGH TEMPERATURES ACROSS MUCH OF THE FORECAST
AREA. WILL HAVE TO KEEP A CLOSE WATCH ON THE CAP AND ANY WEAK
FORCING THAT COULD TRIGGER A THUNDERSTORM. IF A SURFACE BASED STORM
WOULD DEVELOP IT WOULD HAVE THE POTENTIAL TO PRODUCE LARGE HAIL.
THIS LOOKS UNLIKELY AT THIS POINT WITH THE RIDGING OVERHEAD AND
THE CAP STRENGTHENING THROUGH THE LATE AFTERNOON HOURS.

A VIGOROUS WAVE LIFTS NORTH OUT OF THE CENTRAL PLAINS SUNDAY
AFTERNOON AND IS EXPECTED TO MOVE INTO THE UPPER MISSISSIPPI RIVER
VALLEY. THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE LATE MORNING
INTO THE EARLY AFTERNOON HOURS. CAPE AND SHEAR PROFILES WOULD SUPPORT
SEVERE THUNDERSTORMS WITH THE POTENTIAL FOR SUPERCELLS. 0-3 KM MUCAPE
VALUES INCREASE TO AROUND 1700 J/KG OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA BY 18Z ON SUNDAY. 0-6 KM BULK SHEAR OF 25 TO 30
KTS...SUNDAY AFTERNOON...INCREASES TO 35 TO 40 KTS LATE IN THE
AFTERNOON INTO THE EVENING HOURS AS SURFACE LOW PRESSURE DEEPENS
OVER NORTHWEST IOWA/SOUTHEAST SOUTH DAKOTA. 0-1 KM SHEAR ALSO
INCREASES TO AROUND 20 KTS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING. THE HIGHEST CHANCES FOR SEVERE THUNDERSTORMS APPEARS TO
BE ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA SUNDAY AFTERNOON
INTO SUNDAY EVENING. LARGE HAIL...DAMAGING WINDS...AND POSSIBLY AN
ISOLATED TORNADO CANNOT BE RULED OUT. ANOTHER ROUND OF STRONG TO
POSSIBLY SEVERE THUNDERSTORMS ARE POSSIBLE ON MONDAY INTO MONDAY
NIGHT AS THE TROUGH CLOSES INTO A LOW OVER SOUTH DAKOTA AND
EMBEDDED WAVES IN SOUTHWEST FLOW ALOFT CONTINUE TO IMPACT THE
REGION. THE LOW WILL EDGE EAST TUESDAY THROUGH THURSDAY BRINGING
PERIODIC CHANCES FOR SHOWERS AND POSSIBLY THUNDERSTORMS TO THE
REGION. HIGHS WILL FALL INTO THE 70S ON TUESDAY THEN INTO THE 60S
ON WEDNESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1150 PM CDT THU MAY 16 2013

COMPLEX OF STORMS THAT DEVELOPED THIS AFTERNOON OVER NORTHWEST
IOWA HAS BEEN STEADILY ADVANCING EAST TOWARD THE AREA AND
WEAKENING THIS EVENING. STILL SOME SHOWERS AND ISOLATED
THUNDERSTORMS LEFT WITH MOST OBSERVATIONS REPORTING JUST SOME
SPRINKLES FALLING OUT OF A MID LEVEL DECK. THE HRRR THIS EVENING
SEEMS TO HAVE THE BEST HANDLE ON HOW THINGS ARE PLAYING OUT AND
INDICATES THESE SHOWERS WILL MAKE IT INTO KRST BUT MAY FALL APART
BEFORE REACHING KLSE. WILL THUS SHOW A CATEGORICAL SHOWER AT KRST
WITH NO VISIBILITY RESTRICTION AND ONLY A VCSH AT KLSE. THE OTHER
CONCERN FOR TONIGHT IS WHAT THE TRAILING CONVECTION ACROSS
SOUTHWEST MINNESOTA AND NORTHWEST IOWA WILL DO. THE 17.03Z RAP ONLY
SHOWS SOME WEAK MOISTURE TRANSPORT INTO THIS ACTIVITY AND THE HRRR
WHILE HOLDING THIS TOGETHER...FOR THE MOST PART TAKES IT NORTH OF
BOTH TAF SITES. WILL NOT GET FANCY WITH THIS WITH JUST VFR
CONDITIONS EXPECTED AND WILL HOLD THE CATEGORICAL LIGHT SHOWERS AT
KRST THROUGH THE NIGHT EVEN THOUGH IT WILL NOT RAIN THAT LONG AND
KEEP AT VCSH AT KLSE INTO FRIDAY MORNING. THE NEXT CONCERN IS WITH
THE WARM FRONT THAT CUTS ACROSS IOWA. THIS SHOULD LIFT NORTH TOWARD
THE AREA FRIDAY AFTERNOON. STILL SOME CONCERN THAT CONVECTION
COULD DEVELOP ALONG THIS BUT CONFIDENCE STILL NOT HIGH ENOUGH TO
INCLUDE IN THE FORECAST AND WILL JUST SHOW SOME LOWER LEVEL
CUMULUS CLOUDS FOR THE AFTERNOON AND EVENING.

&&

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

$$

SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04

000
FXUS63 KARX 162313
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
613 PM CDT THU MAY 16 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

WEAK HIGH PRESSURE WAS PROVIDING DRY AND QUIET WEATHER ACROSS THE
FORECAST AREA LATE THIS AFTERNOON. MEANWHILE...A SHORTWAVE WAS
MOVING ACROSS WESTERN/CENTRAL NEBRASKA GENERATING SHOWERS AND
THUNDERSTORMS ACROSS THESE AREAS. A WARM FRONT WAS SITUATED FROM
NORTHEAST NEBRASKA STRETCHING SOUTHEAST INTO SOUTH CENTRAL IOWA
THROUGH CENTRAL ILLINOIS. THE WAVE WILL PUSH EAST TONIGHT WITH
SHOWERS AND THUNDERSTORMS SPREADING INTO SOUTHWEST MINNESOTA AND
NORTHWEST IOWA LATE THIS AFTERNOON INTO THIS EVENING. THE WAVE IS
EXPECTED TO SLIDE ACROSS NORTHERN IOWA/SOUTHERN MINNESOTA LATE
TONIGHT...EDGING INTO THE FORECAST AREA AFTER MIDNIGHT TONIGHT.
LOCATIONS WEST OF HIGHWAY 52 WILL SEE THIS ACTIVITY MOVE IN BETWEEN
MIDNIGHT AND 3AM...THEN IT WILL SPREAD EAST TO ALONG THE MISSISSIPPI
RIVER AROUND SUNRISE. 850 MB MOISTURE TRANSPORT FOCUSES MAINLY ALONG
AND NORTH OF THE INTERSTATE 90 CORRIDOR FRIDAY MORNING INTO EARLY
FRIDAY AFTERNOON. FORECAST MODELS ARE SUGGESTING A MORE NORTHERLY
TRACK WITH THE CLUSTER OF SHOWERS AND STORMS SO HAVE INCREASED
PRECIPITATION CHANCES ACROSS SOUTHEAST MINNESOTA THROUGH NORTH
CENTRAL WISCONSIN. THE WARM FRONT IS EXPECTED LIFT NORTH SLIGHTLY ON
FRIDAY AS A POTENT TROUGH DIGS INTO THE SOUTHWEST CONUS AND SURFACE
LOW PRESSURE DEEPENS OVER THE HIGH PLAINS. BY LATE FRIDAY AFTERNOON
THE FRONT IS EXPECTED TO STRETCH FROM FAR SOUTHWEST WISCONSIN
THROUGH SOUTHERN MINNESOTA. THE CLUSTER OF SHOWERS AND STORMS TO
WEAKEN AND PUSH NORTHEAST OF THE AREA DURING THE LATE AFTERNOON.
HOWEVER...MESOSCALE MODELS....SUCH AS THE ARW...NMM...AND SPC WRF
GENERATE SHOWERS AND STORMS ALONG THE FRONT AS IT LIFTS NORTH INTO
THE UPPER MISSISSIPPI RIVER VALLEY. 0-3 KM MUCAPE VALUES CLIMB TO
1500 J/KG. GUIDANCE SUGGESTS THAT DEWPOINTS CLIMB INTO HE LOWER
60S RIGHT ALONG AND BEHIND THE WARM FRONT. THIS SEEMS REASONABLE
LOOKING AT DEWPOINTS BEHIND THE FRONT THIS AFTERNOON WHERE
DEWPOINTS HAVE CLIMBED INTO THE LOWER TO MID 60S. 0-6 KM BULK
SHEAR VALUES APPROACH 30 KTS ACROSS NORTHEAST IOWA...SOUTHEAST
MINNESOTA AND PORTIONS OF SOUTHWEST WISCONSIN. IF STORMS DEVELOP
FRIDAY AFTERNOON NEAR THE WARM FRONT...CANNOT RULE OUT AN ISOLATED
SEVERE STORM. THE MAIN HAZARD WOULD BE LARGE HAIL. HIGH
TEMPERATURES ON FRIDAY WILL RANGE FROM THE UPPER 50S TO AROUND 60
ACROSS FAR NORTHERN WISCONSIN TO THE MID TO UPPER 70S OVER PORTIONS
OF NORTHEAST IOWA.


.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

THE WARM FRONT IS EXPECTED TO DRIFT NORTHWARD FRIDAY NIGHT THROUGH
EARLY SATURDAY MORNING AS A VIGOROUS TROUGH DIGS INTO HE CENTRAL
PLAINS. RIDGING DEVELOPS OVER THE UPPER MISSISSIPPI RIVER VALLEY
FRIDAY NIGHT INTO SATURDAY MORNING AS MOIST...WARM AIR FLOWS INTO
THE FORECAST AREA IN THE WAKE OF THE FRONT. ONCE THE WARM FRONT
LIFTS NORTH OF THE AREA AND RIDGING MOVES IN THERE IS VERY LITTLE
FORCING TO WORK WITH WITHIN THE WARM SECTOR AND WARMER AIR MOVES IN
AT 850 MB...WITH CAPPING HOLDING STRONG THROUGH MUCH OF THE DAY.
DECIDED TO INCREASE HIGH TEMPERATURES ACROSS MUCH OF THE FORECAST
AREA. WILL HAVE TO KEEP A CLOSE WATCH ON THE CAP AND ANY WEAK
FORCING THAT COULD TRIGGER A THUNDERSTORM. IF A SURFACE BASED STORM
WOULD DEVELOP IT WOULD HAVE THE POTENTIAL TO PRODUCE LARGE HAIL.
THIS LOOKS UNLIKELY AT THIS POINT WITH THE RIDGING OVERHEAD AND
THE CAP STRENGTHENING THROUGH THE LATE AFTERNOON HOURS.

A VIGOROUS WAVE LIFTS NORTH OUT OF THE CENTRAL PLAINS SUNDAY
AFTERNOON AND IS EXPECTED TO MOVE INTO THE UPPER MISSISSIPPI RIVER
VALLEY. THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE LATE MORNING
INTO THE EARLY AFTERNOON HOURS. CAPE AND SHEAR PROFILES WOULD SUPPORT
SEVERE THUNDERSTORMS WITH THE POTENTIAL FOR SUPERCELLS. 0-3 KM MUCAPE
VALUES INCREASE TO AROUND 1700 J/KG OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA BY 18Z ON SUNDAY. 0-6 KM BULK SHEAR OF 25 TO 30
KTS...SUNDAY AFTERNOON...INCREASES TO 35 TO 40 KTS LATE IN THE
AFTERNOON INTO THE EVENING HOURS AS SURFACE LOW PRESSURE DEEPENS
OVER NORTHWEST IOWA/SOUTHEAST SOUTH DAKOTA. 0-1 KM SHEAR ALSO
INCREASES TO AROUND 20 KTS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING. THE HIGHEST CHANCES FOR SEVERE THUNDERSTORMS APPEARS TO
BE ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA SUNDAY AFTERNOON
INTO SUNDAY EVENING. LARGE HAIL...DAMAGING WINDS...AND POSSIBLY AN
ISOLATED TORNADO CANNOT BE RULED OUT. ANOTHER ROUND OF STRONG TO
POSSIBLY SEVERE THUNDERSTORMS ARE POSSIBLE ON MONDAY INTO MONDAY
NIGHT AS THE TROUGH CLOSES INTO A LOW OVER SOUTH DAKOTA AND
EMBEDDED WAVES IN SOUTHWEST FLOW ALOFT CONTINUE TO IMPACT THE
REGION. THE LOW WILL EDGE EAST TUESDAY THROUGH THURSDAY BRINGING
PERIODIC CHANCES FOR SHOWERS AND POSSIBLY THUNDERSTORMS TO THE
REGION. HIGHS WILL FALL INTO THE 70S ON TUESDAY THEN INTO THE 60S
ON WEDNESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 613 PM CDT THU MAY 16 2013

COMPLEX OF THUNDERSTORMS HAS DEVELOPED THIS AFTERNOON OVER
NORTHWEST IOWA. REGIONAL RADARS SHOWING AN EASTWARD MOVEMENT TO
THE STORMS. THIS IS THE AREA MANY OF THE MODELS WERE EXPECTING
STORMS TO DEVELOP IN BUT SEVERAL HOURS SOONER THAN EXPECTED. CAPE
ANALYSIS SHOWS THE COMPLEX IS CURRENTLY ON THE NORTHERN EDGE OF
THE CAPE FIELD WHERE MU CAPES OF 500 J/KG OR GREATER EXTEND FROM
ABOUT KSUX TO KMLI. THE 16.21Z RAP SHOWS A SLOW NORTHWARD MOVEMENT
OF THIS CAPE FIELD THROUGH THE NIGHT WITH ML CAPES OF 250-500 J/KG
COMING TO THE AREA AROUND 09Z. THUS EXPECTING THESE STORMS TO
CONTINUE PROGRESSING OFF TO THE EAST/NORTHEAST AND SHOULD START TO
APPROACH BOTH TAF SITES BETWEEN 08Z AND 10Z. AS THE SHORT WAVE
TROUGH HELPING TO FUEL THE STORMS LIFTS OFF TO THE
NORTHEAST...EXPECT THE SHOWERS AND STORMS TO END BY MID MORNING.
GENERALLY EXPECTING VFR CONDITIONS WITH THE STORMS ALTHOUGH CAN
NOT TOTALLY RULE OUT A PERIOD OF MVFR VISIBILITY IF A HEAVIER
SHOWER CAN HIT ONE OF THE AIRPORTS. ONCE THE ACTIVITY MOVES PAST
THE REGION FRIDAY MORNING...A MUDDLED PATTERN LOOKS TO BE IN
PLACE. THE WARM FRONT WILL STILL BE TO THE SOUTH OF THE AREA AND
WITH MOISTURE TRANSPORT INTO THIS...WOULD NOT BE SURPRISED TO SEE
SOME AFTERNOON CONVECTION DEVELOP ALONG IT AS HAPPENED ACROSS IOWA
TODAY. HOWEVER...NOT SURE HOW MUCH CAPE WILL BE PRESENT AS SKIES
COULD REMAIN BROKEN TO OVERCAST WITH CLOUDS FROM TONIGHT/S
ACTIVITY. FOR NOW...WILL NOT INCLUDE ANY AFTERNOON CONVECTION AND
LET LATER SHIFTS TAKE A CLOSER LOOK AT THIS.

&&

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

$$

SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04

000
FXUS63 KARX 162043
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
343 PM CDT THU MAY 16 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

WEAK HIGH PRESSURE WAS PROVIDING DRY AND QUIET WEATHER ACROSS THE
FORECAST AREA LATE THIS AFTERNOON. MEANWHILE...A SHORTWAVE WAS
MOVING ACROSS WESTERN/CENTRAL NEBRASKA GENERATING SHOWERS AND
THUNDERSTORMS ACROSS THESE AREAS. A WARM FRONT WAS SITUATED FROM
NORTHEAST NEBRASKA STRETCHING SOUTHEAST INTO SOUTH CENTRAL IOWA
THROUGH CENTRAL ILLINOIS. THE WAVE WILL PUSH EAST TONIGHT WITH
SHOWERS AND THUNDERSTORMS SPREADING INTO SOUTHWEST MINNESOTA AND
NORTHWEST IOWA LATE THIS AFTERNOON INTO THIS EVENING. THE WAVE IS
EXPECTED TO SLIDE ACROSS NORTHERN IOWA/SOUTHERN MINNESOTA LATE
TONIGHT...EDGING INTO THE FORECAST AREA AFTER MIDNIGHT TONIGHT.
LOCATIONS WEST OF HIGHWAY 52 WILL SEE THIS ACTIVITY MOVE IN BETWEEN
MIDNIGHT AND 3AM...THEN IT WILL SPREAD EAST TO ALONG THE MISSISSIPPI
RIVER AROUND SUNRISE. 850 MB MOISTURE TRANSPORT FOCUSES MAINLY ALONG
AND NORTH OF THE INTERSTATE 90 CORRIDOR FRIDAY MORNING INTO EARLY
FRIDAY AFTERNOON. FORECAST MODELS ARE SUGGESTING A MORE NORTHERLY
TRACK WITH THE CLUSTER OF SHOWERS AND STORMS SO HAVE INCREASED
PRECIPITATION CHANCES ACROSS SOUTHEAST MINNESOTA THROUGH NORTH
CENTRAL WISCONSIN. THE WARM FRONT IS EXPECTED LIFT NORTH SLIGHTLY ON
FRIDAY AS A POTENT TROUGH DIGS INTO THE SOUTHWEST CONUS AND SURFACE
LOW PRESSURE DEEPENS OVER THE HIGH PLAINS. BY LATE FRIDAY AFTERNOON
THE FRONT IS EXPECTED TO STRETCH FROM FAR SOUTHWEST WISCONSIN
THROUGH SOUTHERN MINNESOTA. THE CLUSTER OF SHOWERS AND STORMS TO
WEAKEN AND PUSH NORTHEAST OF THE AREA DURING THE LATE AFTERNOON.
HOWEVER...MESOSCALE MODELS....SUCH AS THE ARW...NMM...AND SPC WRF
GENERATE SHOWERS AND STORMS ALONG THE FRONT AS IT LIFTS NORTH INTO
THE UPPER MISSISSIPPI RIVER VALLEY. 0-3 KM MUCAPE VALUES CLIMB TO
1500 J/KG. GUIDANCE SUGGESTS THAT DEWPOINTS CLIMB INTO HE LOWER
60S RIGHT ALONG AND BEHIND THE WARM FRONT. THIS SEEMS REASONABLE
LOOKING AT DEWPOINTS BEHIND THE FRONT THIS AFTERNOON WHERE
DEWPOINTS HAVE CLIMBED INTO THE LOWER TO MID 60S. 0-6 KM BULK
SHEAR VALUES APPROACH 30 KTS ACROSS NORTHEAST IOWA...SOUTHEAST
MINNESOTA AND PORTIONS OF SOUTHWEST WISCONSIN. IF STORMS DEVELOP
FRIDAY AFTERNOON NEAR THE WARM FRONT...CANNOT RULE OUT AN ISOLATED
SEVERE STORM. THE MAIN HAZARD WOULD BE LARGE HAIL. HIGH
TEMPERATURES ON FRIDAY WILL RANGE FROM THE UPPER 50S TO AROUND 60
ACROSS FAR NORTHERN WISCONSIN TO THE MID TO UPPER 70S OVER PORTIONS
OF NORTHEAST IOWA.


.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

THE WARM FRONT IS EXPECTED TO DRIFT NORTHWARD FRIDAY NIGHT THROUGH
EARLY SATURDAY MORNING AS A VIGOROUS TROUGH DIGS INTO HE CENTRAL
PLAINS. RIDGING DEVELOPS OVER THE UPPER MISSISSIPPI RIVER VALLEY
FRIDAY NIGHT INTO SATURDAY MORNING AS MOIST...WARM AIR FLOWS INTO
THE FORECAST AREA IN THE WAKE OF THE FRONT. ONCE THE WARM FRONT
LIFTS NORTH OF THE AREA AND RIDGING MOVES IN THERE IS VERY LITTLE
FORCING TO WORK WITH WITHIN THE WARM SECTOR AND WARMER AIR MOVES IN
AT 850 MB...WITH CAPPING HOLDING STRONG THROUGH MUCH OF THE DAY.
DECIDED TO INCREASE HIGH TEMPERATURES ACROSS MUCH OF THE FORECAST
AREA. WILL HAVE TO KEEP A CLOSE WATCH ON THE CAP AND ANY WEAK
FORCING THAT COULD TRIGGER A THUNDERSTORM. IF A SURFACE BASED STORM
WOULD DEVELOP IT WOULD HAVE THE POTENTIAL TO PRODUCE LARGE HAIL.
THIS LOOKS UNLIKELY AT THIS POINT WITH THE RIDGING OVERHEAD AND
THE CAP STRENGTHENING THROUGH THE LATE AFTERNOON HOURS.

A VIGOROUS WAVE LIFTS NORTH OUT OF THE CENTRAL PLAINS SUNDAY
AFTERNOON AND IS EXPECTED TO MOVE INTO THE UPPER MISSISSIPPI RIVER
VALLEY. THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE LATE MORNING
INTO THE EARLY AFTERNOON HOURS. CAPE AND SHEAR PROFILES WOULD SUPPORT
SEVERE THUNDERSTORMS WITH THE POTENTIAL FOR SUPERCELLS. 0-3 KM MUCAPE
VALUES INCREASE TO AROUND 1700 J/KG OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA BY 18Z ON SUNDAY. 0-6 KM BULK SHEAR OF 25 TO 30
KTS...SUNDAY AFTERNOON...INCREASES TO 35 TO 40 KTS LATE IN THE
AFTERNOON INTO THE EVENING HOURS AS SURFACE LOW PRESSURE DEEPENS
OVER NORTHWEST IOWA/SOUTHEAST SOUTH DAKOTA. 0-1 KM SHEAR ALSO
INCREASES TO AROUND 20 KTS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING. THE HIGHEST CHANCES FOR SEVERE THUNDERSTORMS APPEARS TO
BE ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA SUNDAY AFTERNOON
INTO SUNDAY EVENING. LARGE HAIL...DAMAGING WINDS...AND POSSIBLY AN
ISOLATED TORNADO CANNOT BE RULED OUT. ANOTHER ROUND OF STRONG TO
POSSIBLY SEVERE THUNDERSTORMS ARE POSSIBLE ON MONDAY INTO MONDAY
NIGHT AS THE TROUGH CLOSES INTO A LOW OVER SOUTH DAKOTA AND
EMBEDDED WAVES IN SOUTHWEST FLOW ALOFT CONTINUE TO IMPACT THE
REGION. THE LOW WILL EDGE EAST TUESDAY THROUGH THURSDAY BRINGING
PERIODIC CHANCES FOR SHOWERS AND POSSIBLY THUNDERSTORMS TO THE
REGION. HIGHS WILL FALL INTO THE 70S ON TUESDAY THEN INTO THE 60S
ON WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM CDT THU MAY 16 2013

HIGH PRESSURE WILL PROVIDE VFR CONDITIONS THIS AFTERNOON.

FOR TONIGHT...A THUNDERSTORM COMPLEX /CURRENTLY DEVELOPING ACROSS
SOUTH CENTRAL SOUTH DAKOTA AND NORTH CENTRAL NEBRASKA/ WILL MOVE
INTO KRST AROUND 17.08Z AND KLSE AROUND 17.11Z. AS THIS SYSTEM
APPROACHES THE AREA,,,CEILINGS WILL GRADUALLY LOWER FROM 20K LATE
THIS AFTERNOON TO 3-4K AFTER 17.08Z. THE SOUNDINGS ARE SUGGESTING
THAT THERE WILL BE POTENTIAL FOR MVFR CEILINGS. HOWEVER WITH THE
MODELS OVERDOING THE LOW LEVEL MOISTURE LATELY AND NO CEILINGS
THAT LOW CURRENTLY...HAVE HELD OFF ADDING IT TO THE TAFS AT THIS TIME.


&&

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

$$

SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...BOYNE

000
FXUS63 KARX 161749
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1249 PM CDT THU MAY 16 2013

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CDT THU MAY 16 2013

REMNANTS OF THE COLD FRONT THAT WENT THROUGH ON TUESDAY WAS STALLED
SOUTH OF OUR AREA...FROM CENTRAL IL INTO SOUTHERN IA. LOW LEVEL
925-850MB JET OF 30-35KT IMPINGING ON THIS FRONT WAS PRODUCING A
NARROW BAND SHRA/TS ALONG THE FRONTAL BOUNDARY. MEANWHILE...A TROUGH
WAS PUSHING SOUTHWARD INTO NORTHERN MN/UPPER MI. THIS WAS PRODUCING
SOME ACCAS ACROSS NORTHERN WI. ALTHOUGH RADAR WAS PICKING UP SOME
ECHOES ACROSS THAT AREA...SURFACE OBSERVATIONS WERE MOSTLY DRY
ACROSS THAT AREA THUS FAR. OTHERWISE...MOSTLY CLEAR SKIES WERE NOTED
ON IR SATELLITE ACROSS OUR FORECAST AREA WITH TEMPERATURES RANGING
FROM THE MIDDLE 40S ACROSS THE CRANBERRY BOG COUNTRY OF CENTRAL
WI...TO THE MID/UPPER 50S ELSEWHERE.

FOR TODAY...LOOK FOR THAT TROUGH OVER NORTHERN MN/UPPER MI TO DROP
SOUTH ACROSS WI TODAY. BUFKIT SOUNDINGS SHOW ANY CUMULUS THAT FORMS
ALONG THIS TROUGH WILL BE VERY HIGH BASED...AND WITH WEAK
FORCING...THIS TROUGH LOOKS TO PASS THROUGH DRY. ANY SHOWER CHANCES
EXPECTED TO BE OVER EASTERN WI WERE CONVERGENCE WILL BE ENHANCED
SOMEWHAT. HIGH PRESSURE OVER WESTERN ONTARIO WILL THEN BUILD SOUTH
INTO THE GREAT LAKES REGION THIS AFTERNOON. THIS WILL SET UP A
DRYING NORTHEAST FLOW FOR AREAS ALONG AND NORTHEAST OF I-94.
OTHERWISE...DEBRIS MID/HIGH CLOUD FROM DEVELOPING COMPLEX OF SHRA/TS
OVER THE PLAINS WILL MAKE THEIR WAS EAST INTO THE AREA LATER THIS
AFTERNOON. HIGHS TODAY ARE EXPECTED TO TOP OFF IN THE MID 70S ACROSS
NORTH CENTRAL WI...TO NEAR THE 80 DEGREE MARK ACROSS THE REST OF THE
FORECAST AREA.

FOR TONIGHT...WILL SEE INCREASING 850MB MOISTURE TRANSPORT AHEAD OF
A MID-LEVEL TROUGH EJECTING OUT OF THE ROCKIES. THIS WILL IMPINGE ON
A SURFACE WARM FRONT EXTENDING FROM THE CENTRAL PLAINS INTO
IA/NORTHERN IL. THIS PROCESS IS EXPECTED TO FIRE A VIGOROUS COMPLEX
OF SHRA/TS ACROSS SD IN THE EVENING...WITH THE COMPLEX HEADING
NORTHEAST INTO CENTRAL MN BY FRIDAY DAYBREAK. OUR FORECAST AREA WILL
BE ON THE EASTERN FRINGES OF THIS COMPLEX AWAY FROM THE BETTER
THERMODYNAMIC/MOISTURE TRANSPORT FORCING. SO...FOR OUR AREA...WILL
KEEP HIGHER SHRA/TS CHANCES WEST OF THE MISSISSIPPI RIVER WITH
DECREASING CHANCES EAST. MODELS PRODUCING JUST A FEW HUNDRED J/KG IN
THE 1-6KM LAYER...SO ANY THUNDERSTORM THAT DOES DEVELOP/MOVE INTO
OUR AREA IS EXPECTED TO REMAIN BELOW SEVERE LIMITS.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 338 AM CDT THU MAY 16 2013

MODELS COMING INTO BETTER AGREEMENT TAKING THE COMPLEX OF
THUNDERSTORMS FROM CENTRAL MN FRIDAY MORNING INTO FAR NORTHWEST WI
BY LATE IN THE AFTERNOON AS NOSE OF BETTER 850MB MOISTURE TRANSPORT
HEADS UP THAT WAY AHEAD OF A WARM FRONT ADVANCING NORTHWARD INTO THE
AREA. FARTHER SOUTH ACROSS OUR AREA AHEAD OF THE WARM FRONT...BUFKIT
SHOWING ELEVATED SHRA/TS ACTIVITY THROUGH THE DAY. AGAIN...
INSTABILITY VERY LIMITED...SO NOT EXPECTING ANYTHING SEVERE. WITH
THE CLOUDS AND SCATTERED PRECIPITATION ABOUT THE AREA...LOOK FOR
HIGHS RANGING FROM THE LOWER 60S ACROSS NORTH CENTRAL WI...TO THE
MIDDLE 70S ACROSS NORTHEAST IA/FAR SOUTHWEST WI.

FOR FRIDAY NIGHT THROUGH SATURDAY...WILL BE WATCHING THE WARM FRONT
CONTINUE TO PUSH NORTH ACROSS THE AREA...PUSHING THE BULK OF THE
SHRA/TS ACTIVITY NORTH OF I-94 BY SATURDAY AFTERNOON AS MID-LEVEL
RIDGING BUILDS AHEAD OF A DEEPENING TROUGH OVER THE PLAINS. APPEARS
THE AREA WILL BE IN THE CAPPED WARM SECTOR SATURDAY NIGHT INTO
SUNDAY MORNING WITH THE SURFACE LOW PRESSURE CONTINUING TO DEEPEN
OVER THE PLAINS. AS SUCH...REMOVED BULK OF SHRA/TS CHANCES FROM
SATURDAY NIGHT WITH CONVECTION REMAINING WEST OF THE AREA.

SUNDAY THROUGH WEDNESDAY STILL LOOKING LIKE AN ACTIVE PERIOD WITH
SHRA/TS. TRYING TO PIN DOWN EXACT TIMING OF HIGHEST SEVERE THREAT
STILL A BIT DIFFICULT AT THIS POINT. ECMWF/GFS SHOWING COLD FRONTAL
PASSAGE NOW OCCURRING SOME TIME SUNDAY NIGHT WITH BETTER
THERMODYNAMIC FORCING OCCURRING MONDAY AFTERNOON WITH COOLING ALOFT
AS THE UPPER LOW APPROACHES. UPPER LEVEL FLOW ALSO A BIT MORE
DIFFLUENT AHEAD OF THE NEUTRAL/NEGATIVELY TILTED LOW. WILL CONTINUE
TO ASSESS OVER THE NEXT COUPLE OF DAYS.

TEMPERATURE-WISE...LOOK FOR HIGHS IN THE 70S SATURDAY WITH PERHAPS A
FEW 80S ACROSS NORTHEAST IA...75-80 ON SUNDAY...THEN COOLING INTO
THE MID 60S/NEAR 70 BY TUESDAY AND WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM CDT THU MAY 16 2013

HIGH PRESSURE WILL PROVIDE VFR CONDITIONS THIS AFTERNOON.

FOR TONIGHT...A THUNDERSTORM COMPLEX /CURRENTLY DEVELOPING ACROSS
SOUTH CENTRAL SOUTH DAKOTA AND NORTH CENTRAL NEBRASKA/ WILL MOVE
INTO KRST AROUND 17.08Z AND KLSE AROUND 17.11Z. AS THIS SYSTEM
APPROACHES THE AREA,,,CEILINGS WILL GRADUALLY LOWER FROM 20K LATE
THIS AFTERNOON TO 3-4K AFTER 17.08Z. THE SOUNDINGS ARE SUGGESTING
THAT THERE WILL BE POTENTIAL FOR MVFR CEILINGS. HOWEVER WITH THE
MODELS OVERDOING THE LOW LEVEL MOISTURE LATELY AND NO CEILINGS
THAT LOW CURRENTLY...HAVE HELD OFF ADDING IT TO THE TAFS AT THIS TIME.

&&

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

$$

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