000
FXUS63 KARX 132005
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
305 PM CDT MON MAY 13 2013

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 305 PM CDT MON MAY 13 2013

OVER ALL TREND OF RISING HEIGHTS AND MORE ACTIVE SPRING WEATHER
CERTAINLY ON TAP THIS ENTIRE FORECAST. FIRST CHALLENGE WILL BE
TEMPERATURES TUESDAY AND ANY RELATED FIRE WEATHER CONCERNS WEST OF
MISSISSIPPI RIVER. THEN FOCUS STARTS SHIFTING TO LATE IN THE WEEK
WHEN POTENTIAL WET AND STORMY WEEKEND SETS UP.

WITH UPPER HEIGHTS RISING RAPIDLY TODAY...WARM AIR ADVECTION KICKING
IN AS WELL. MID LEVEL WARM AIR AND MOISTURE ADVECTION HAS LED TO
NARROW BAND OF SHOWERS PASSING THROUGH AREA BUT THAT SHOULD CONTINUE
TO SHIFT EAST AND END THIS EVENING. EXPECT MINIMAL TEMPERATURE DROP
TONIGHT...ESPECIALLY IN WEST WHERE ADVECTION IS STRONGEST.

ON TUESDAY SHORT TERM UPPER RIDGE WILL BE IN PLACE WITH WARM AIR
ADVECTION CONTINUING. AS WARM SECTOR MOVES THROUGH...EXPECT BREEZY
SOUTHWEST WINDS AND BIG BOOST IN AFTERNOON TEMPERATURES AHEAD OF AN
APPROACHING COLD FRONT. SOME CONCERNS THAT HIGH CLOUDS SPILLING OVER
RIDGE COULD BE THICK ENOUGH TO HOLD TEMPERATURES BACK FROM GETTING
TOO OUT OF HAND SO WILL RIDE CURRENT FORECAST FROM LOWER 90S IN WEST
TO NEAR 80 IN NORTH CENTRAL WISCONSIN.

AS QUICK AS RIDGE BUILDS IN SHORT WAVE FLATTENS IT AND DRAGS COLD
FRONT INTO NORTHERN STATES LATE TUESDAY. MOISTURE WILL BE LACKING
AND AIRMASS LIKELY CAPPED. IF ANY CONVECTION CAN FORM ALONG
BOUNDARY...HIGH BASED STORM POSSIBLE SO WILL LEAVE VERY MINOR RAIN
THREAT IN THERE GOING INTO TUESDAY EVENING. MOST AREAS WILL REMAIN
DRY.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 305 PM CDT MON MAY 13 2013

AFTER BRIEF PERIOD OF ZONAL FLOW AND SLIGHT COOL DOWN MID WEEK...
UPPER FLOW AGAIN BECOMES AMPLIFIED WHICH WILL BRING RIDGE BACK BY
END OF THE WEEK ALONG WITH A FEW DRY DAYS.

WARM AIR ADVECTION IN RESPONSE TO AMPLIFIED FLOW COULD BEGIN TO
GENERATE THUNDERSTORMS AS EARLY AS THURSDAY NIGHT AS WARM FRONT
SLIDES IN. THIS COULD ALSO PLAY HAVOC WITH TEMPERATURES ON FRIDAY
WITH DEBRIS CLOUDS STILL AROUND OR MORNING CONVECTION MOVING ON OUT
SO KEPT TEMPERATURES DOWN A BIT EVEN THOUGH RIDGE IN PLACE.

DISCREPENCIES IN MEDIUM RANGE GUIDANCE STILL LEAVE UNCERTAINTY FOR
DETAILS OVER THE WEEKEND...BUT BECOMING MORE AND MORE CLEAR THAT IT
WILL BE ACTIVE. DEPENDING ON STRENGTH OF DYNAMICS AND LOCATION OF
UPPER LOW AS IT MOVES INTO NORTHERN MIDWEST COULD DETERMINE BEST
RISK OF THUNDERSTORMS...SOME SEVERE AS COLD FRONT EVENTUALLY PUSHES
IN. AT THIS POINT SUNDAY LOOKS LIKE A SEVERE POTENTIAL BUT TOO FAR
OUT TO DETERMINE ANY DETAILS. ALL GUIDANCE SUGGESTS THIS SAME UPPER
LOW WILL SLOW UP THOUGH AS COLDER AIR RETURNS AND KEEPS SHOWER
THREAT GOING INTO EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1225 PM CDT MON MAY 13 2013

MID LEVEL MOISTURE AND LIFT SPREADING EAST ACROSS THE UPPER MIDWEST
WERE PRODUCING AN LINE OF WEAK -SHRA/SPRINKLES ACROSS CENTRAL MN.
THESE WILL SPREAD EAST/SOUTHEAST ACROSS THE KRST AREA 18-21Z AND
KLSE IN THE 20-23Z WINDOW. WITH PLENTY OF LOWER LEVEL DRY AIR...
CONDITIONS EXPECTED TO REMAIN VFR AS THIS LINE OF -SHRA PASSES.
WINDS WILL INCREASE AS THE GRADIENT TIGHTENS THIS AFTERNOON...THEN
DECREASE AS THE GRADIENT RELAXES TONIGHT. SOME LLWS EXPECTED DURING
THE LATE EVENING AND OVER NIGHT AT DECOUPLED/VALLEY SITES LIKE
KLSE...WITH BOUNDARY LAYER WINDS LIGHT SOUTH-SOUTHEAST AND WINDS AT
1.5K FT IN THE 35-40KT RANGE FROM THE SOUTHWEST. THE 1.5K FT WINDS
DECREASE BY 12Z TUE WITH QUICK PASSAGE OF THE 925-850MB TROUGH.
ANOTHER TROUGH/WARM FRONT APPROACHES/PASSES TUE WITH WINDS AGAIN
INCREASING FOR THE LATER MORNING/AFTERNOON. AIRMASS IS QUITE DRY
WITH THE WARM FRONT FOR TUE...WITH CIGS/VSBYS REMAINING VFR THRU TUE.

&&

.FIRE WEATHER...TUESDAY
ISSUED AT 305 PM CDT MON MAY 13 2013

AS WE GET INTO WARM SECTOR OF WEATHER SYSTEM ON TUESDAY...
EXPECT BREEZY SOUTHWEST WINDS AND RAPID RISES IN TEMPERATURES BY
TUESDAY AFTERNOON. SHORT TERM MODEL GUIDANCE SEEMS WAY OVER DONE
WITH SURFACE DEW POINTS...ESPECIALLY WITH NO CROPS IN PLACE AND
CURRENT TRENDS IN OBSERVATIONS. WILL BE UNDER CUTTING MODEL DEW
POINTS SO EXPECT RELATIVE HUMIDITIES TUESDAY AFTERNOON TO APPROACH
20-25 PERCENT. SOME UNCERTAINTY IN AMOUNT OF CLOUD COVER THAT COULD
LIMIT MIXING AND THREAT FOR LOWER RH VALUES...BUT GIVEN HOW CLOSE WE
COULD BE TO RED FLAG WARNING CRITERIA...WILL ISSUE FIRE WEATHER
WATCH FOR FAR WESTERN AREA TUESDAY AFTERNOON.

&&

.CLIMATE...TUESDAY
ISSUED AT 344 AM CDT MON MAY 13 2013

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

IOWA...

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

MINNESOTA...

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

WISCONSIN...

LA CROSSE         92 IN 2007
PRAIRIE DU CHIEN  92 IN 1932
SPARTA            88 IN 1991
MEDFORD           87 IN 1991
RICHLAND CENTER   89 IN 1932
VIROQUA           90 IN 1932

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FIRE WEATHER WATCH TUESDAY AFTERNOON AND EARLY EVENING
     FOR MNZ086-094.
IA...FIRE WEATHER WATCH TUESDAY AFTERNOON AND EARLY EVENING
     FOR IAZ008-018.
&&

$$

SHORT TERM.....SHEA
LONG TERM......SHEA
AVIATION.......RRS
FIRE WEATHER...SHEA
CLIMATE........AJ