Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 061127
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
627 AM CDT SUN JUL 6 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN JUL 6 2014

RAIN CHANCES ON THE FOREFRONT TODAY WITH REMNANTS OF CURRENT MN
PERHAPS MAKING IT INTO THE AREA BY DAYBREAK...AND RENEWED THREAT
FOR STRONG CONVECTION THIS AFTERNOON WITH WARM AND MUGGY AIRMASS
IN PLACE AHEAD OF A PASSING COLD FRONT.

FIRST...MOISTURE POOLING ALONG THE FRONT WHICH EXTENDS FROM
NORTHWEST MN INTO EASTERN ND HELPED FUEL STORMS LAST EVENING WHICH
HAVE BEEN SLOWLY WORKING EAST INTO MN. HOW THIS SYSTEM EVOLVES AND
EVENTUALLY AFFECTS OUR AREA IS QUESTION MARK #1. ALTHOUGH NONE OF
THE MODELS HAVE A REALLY GOOD GRASP ON THIS CURRENT ACTIVITY...
MANY OF THE MESOSCALE MODELS HAVE SOME SEMBLANCE OF CONVECTION IN
THAT GENERAL AREA. WHAT THEY DO AGREE ON IS A RAPID WEAKENING OF
ACTIVITY SHORTLY AFTER SUNRISE AND BEFORE IT REALLY GETS HERE.
STILL BANKING ON THIS SCENARIO. REMNANT CLOUD COVER COULD ALSO
HAMPER HEATING TODAY...KEEPING TEMPERATURES A BIT COOLER AND THUS
LIMITING THE INSTABILITY SOMEWHAT. MODELS DO GRASP THIS WITH LOWER
CAPE OUTPUT THAN PREVIOUS RUNS. STILL...A HUMID AIRMASS WILL BE IN
PLACE AND WITH THE APPROACHING FRONT AND ASSOCIATED UPPER LEVEL
SHORT WAVE TROUGH...STILL LOOKING LIKE STRONG TO SEVERE CONVECTION
WILL DEVELOP THIS AFTERNOON ALONG THE FRONT. AT THIS POINT THE
STORM INITIATION AREA LOOKS TO BE RIGHT OVER THE FORECAST AREA...
AS THE FRONT IS EXPECTED TO BE MOVING THROUGH RIGHT DURING THE
PEAK HEATING TIME. EXPECT INITIATION 19-20Z TIMEFRAME FROM NORTH
CENTRAL WI BACK TOWARD SOUTHEAST MN. THIS TREND HAS BEEN
ANTICIPATED FOR A FEW DAYS NOW SO LITTLE CHANGE WAS NECESSARY TO
THE FORECAST. GIVEN THE EXPECTED SHEAR AND CAPE VALUES...EXPECT
THE PRIMARY THREAT TO BE FROM DAMAGING WINDS AND LARGE HAIL. BUT
0-1KM SHEAR 10-20 KTS WILL BE SUFFICIENT SO AS TO NOT PRECLUDE THE
THREAT FOR AN ISOLATED TORNADO AS WELL. THE STORMS WILL LIKELY
HAVE A HIGH RAINFALL RATE TOO...BUT SHOULD BE MOVING ENOUGH THAT A
WIDESPREAD FLOOD RISK IS NOT ANTICIPATED. RAIN AREA SHOULD PUSH
SOUTHEAST OUT OF THE AREA BY MIDNIGHT AS THE FRONT MOVES AWAY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN JUL 6 2014

ANOTHER SHORT WAVE TROUGH AND REINFORCING COLD FRONT WILL BE
MOVING THROUGH THE REGION ON MONDAY. THIS TROUGH IS STRONGER...
BUT DOES NOT HAVE THE SAME JUICY AIRMASS TO WORK WITH. STILL...
GIVEN THE STRENGTH OF THE FORCING AND STEEP LAPSE RATES THAT
LOOK TO BE PRESENT...THERE WILL BE A RISK FOR DAMAGING WINDS AND
LARGE HAIL WITH SOME OF THE STRONGER STORMS. CYCLONIC FLOW AROUND
THE LONG WAVE TROUGH THAT REACHES FROM HUDSON BAY DOWN INTO THE
GREAT LAKES ALONG WITH COOL TEMPERATURES SHOULD LEAD TO A SMALL
CHANCE FOR SOME MAINLY DIURNAL SHOWERS/ISO TSRA INTO TUESDAY
BEFORE HIGH PRESSURE SETTLES IN FOR WEDNESDAY AND THURSDAY. THE
UPPER FLOW PATTERN GOES MORE ZONAL AFTER THAT...WITH SEVERAL
WEAKER SHORT WAVES EXPECTED TO MOVE THROUGH THE REGION. CONFIDENCE
IS LOW IN PINNING DOWN THE TIMING ON ANY RAIN THREAT...BUT SUFFICE
TO SAY THAT THERE WILL BE CHANCES STARTING ABOUT THURSDAY NIGHT
AND PERSISTING INTO THE WEEKEND. OVERALL...TEMPERATURES THROUGH
THE EXTENDED PERIOD LOOK TO BE BELOW NORMAL...BUT A RETURN TO MORE
NORMAL READINGS IS ANTICIPATED BY NEXT WEEKEND.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 627 AM CDT SUN JUL 6 2014

COMPLICATED FORECAST TODAY. FIRST...WILL HAVE TO DEAL WITH SOME
MORNING LIFR STRATUS/FOG EARLY ON THIS MORNING. EXPECT THIS TO
LIFT...EVENTUALLY BECOMING VFR CONDITIONS BY 16Z. SECONDLY...WILL
BE WATCHING A DYING CLUSTER OF STORMS MOVING SOUTHEAST ACROSS
CENTRAL MN. THINKING THIS SHOULD STAY NORTH OF THE KRST/KLSE TAF
SITES...BUT BEARS WATCHING. THIRD...WILL BE KEEPING AN EYE ON
DEVELOPMENT OF POTENTIALLY SEVERE THUNDERSTORMS AS A COLD FRONT
MOVES THROUGH THE REGION THIS AFTERNOON. EXPECTING MOST OF THIS
ACTIVITY TO FIRE MAINLY EAST OF KRST BY 20Z WITH KLSE LIKELY TO
GET CLIPPED BY THE STORMS BY 21Z. THE COLD FRONT AND THIS
THUNDERSTORM ACTIVITY SHOULD CLEAR THE AREA BY 00-01Z...WITH VFR
CONDITIONS EXPECTED DURING THE OVERNIGHT HOURS.

&&

.HYDROLOGY...
ISSUED AT 257 AM CDT SUN JUL 6 2014

THE MISSISSIPPI RIVER IS PAST CREST AT ALL LOCATIONS IN OUR
SERVICE AREA...AND SHOULD CONTINUE TO FALL OVER THE NEXT WEEK.
THE RAIN TODAY AND MONDAY SHOULD NOT BE ENOUGH TO REVERSE THAT
TREND. OTHER CREEKS AND RIVERS ARE NEARLY BACK TO NORMAL BASE FLOW
LEVELS...SO THEY SHOULD ALSO BE ABLE TO HANDLE THE EXPECTED RAINFALL
OVER THE NEXT 48 HOURS.

&&

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

$$

SHORT TERM...MW
LONG TERM...MW
AVIATION...DAS
HYDROLOGY...MW


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