000
FXUS63 KARX 160838
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
338 AM 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 OCCURING 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 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT
1155 PM CDT WED MAY 15 2013

HIGH PRESSURE FROM MANITOBA AND ONTARIO CONTINUES TO EXTEND DOWN
INTO THE AREA LATE THIS EVENING. STILL SOME SCATTERED MID LEVEL
CLOUDS FLOATING AROUND UNDER THE RIDGE AXIS. EXPECT THIS TO BE THE
CASE THE REMAINDER OF THE NIGHT AS THE HIGH DRIFTS SLOWLY OFF TO
THE EAST. WINDS WILL BE LIGHT UNTIL THE RIDGE AXIS GETS OFF THE
EAST THURSDAY MORNING WHEN A LIGHT EAST TO SOUTHEAST FLOW WILL SET
UP. THE 16.00Z NAM BUFKIT SOUNDINGS CONTINUE TO SHOW THE POTENTIAL
FOR SOME AFTERNOON CUMULUS CLOUDS AND WILL MAINTAIN THESE IN THE
UPCOMING TAFS. A SHORT WAVE TROUGH COMING ACROSS THE NORTHERN
ROCKIES IS EXPECTED TO SPARK A MCS THURSDAY EVENING IN THE
MOISTURE RETURN ON THE BACK SIDE OF THE DEPARTING HIGH. SHOULD
START TO SEE A HIGH VFR CEILING MOVE IN THURSDAY EVENING AHEAD OF
THIS FEATURE. PLENTY OF MODEL DIFFERENCES ON THE TRACK OF THE MCS
ONCE IT FORMS WITH SOME MODELS TAKING IT NORTH OF THE AREA WHILE
OTHERS BRING IT INTO THE FORECAST AREA AND POSSIBLY IMPACT KRST
BEFORE 12Z FRIDAY.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...

WI...NONE.
MN...NONE.
IA...NONE.

&&

$$

SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04