Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 281132
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
632 AM CDT THU APR 28 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CDT THU APR 28 2016

SEVERAL CONCERNS IN THE SHORT TERM PERIOD: RAIN TODAY...TAPERING
OFF TONIGHT...ANY POSSIBLE CLEARING...AND POTENTIAL FOR FOG AND EVEN
SOME PATCHY FROST IN OUR TYPICAL COLD SPOTS.

LATEST ANALYSIS SHOWS THE STACKED LOW SPINNING OVER WESTERN IA WITH
RAIN/SHOWERS/T-STORMS SPIRALING AROUND IT. LATEST RADAR TRENDS SHOW
A GENERAL DECREASE IN RAIN RATES AS THE CONVECTIVE ELEMENTS WEAKEN.
EVEN SOME REPORTS OF SNOW MIXING IN ON THE NORTHERN AND WESTERN
EDGES WHERE DRY AIR NEAR THE SURFACE IS ALLOWING EVAPORATIVE COOLING
TO ALLOW SNOW TO SURVIVE THE TRIP DOWN TO THE SURFACE. HOWEVER THERE
WILL CONTINUE TO BE PLENTY OF DYNAMIC LIFT TODAY...AS WELL AS
ISENTROPIC/FRONTOGENETIC MAXIMA ALONG THE NORTHERN PERIPHERY OF THE
SYSTEM AS IT TRACKS EAST TOWARD THE GREAT LAKES AND SHEARS OUT AND
WEAKENS. EXPECTING ANY REMAINING RAIN TO BE DONE BY MIDNIGHT...AND
THE ATTENTION THEN SHIFTS TO IF/WHEN WE WILL GET ANY CLEARING.
PREVIOUS MODEL RUNS WERE SUGGESTING CLEARING COULD BEGIN OVER
NORTHEAST WI AS DRY EASTERLY FLOW WORKED IN BEHIND THE DEPARTING
SYSTEM. BUT RECENT SOLUTIONS HAVE SUGGESTED THE CLOUD COVER WILL
HOLD ON LONGER. IF WE CLEARED...TEMPERATURES WOULD BE COOLER AND
THERE WOULD BE POTENTIAL FOR FROST. BUT IF THE BLANKET OF CLOUDS
REMAIN...TEMPERATURES WILL BE A BIT WARMER WITH NO FROST. HAVE OPTED
TO MOVE TOWARD THE CLOUDY/WARM THINKING...AND HAVE REMOVED THE FROST
POTENTIAL. ALSO...DESPITE PLENTY OF RECENT RAIN...THERE SHOULD
ENOUGH WIND AND ADVECTION OF DRIER BOUNDARY LAYER AIR INTO THE
REGION TO PRECLUDE MUCH FOG. BUT IF WINDS DO SLACKEN MORE THAN
ANTICIPATED...FOG WILL BECOME MORE OF AN ISSUE.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CDT THU APR 28 2016

FRIDAY STILL LOOKS LIKE A DRY DAY AS A BRIEF PERIOD OF RIDGING
BUILDS OVER THE AREA. BUT WE GET SQUISHED BETWEEN TWO SYSTEMS FOR
SATURDAY. ONE CLOSED LOW OVER THE DESERT SOUTHWEST BEGINS TO EJECT
TOWARD THE UPPER MIDWEST...BUT ANOTHER STRONG SHORT WAVE TROUGH
DROPS SOUTH OUT OF ONTARIO INTO THE WESTERN GREAT LAKES AS WELL. THE
PRIMARY WEATHER MAKER FOR THE AREA WILL BE THE SOUTHERN SYSTEM...
BUT THE NORTHERN SYSTEM MAY HELP TO SHUNT SOME OF THE BEST DYNAMICS
AND FRONTOGENETIC FOCUS OVER THE SOUTH. HAVE GONE AHEAD AND
BOOSTED POPS UP FOR SATURDAY...WITH A RELATIVELY TIGHT GRADIENT TO
LOWER POPS OVER THE FAR NORTHERN COUNTIES. ANY LINGERING
PRECIPITATION SHOULD BE SHIFTING SOUTH ON SUNDAY.

THERE IS A BIT OF A PATTERN SHIFT GOING INTO NEXT WEEK AS WE ARE
CAUGHT ON THE WESTERN EDGE OF A LARGE EAST COAST TROUGH. THIS WILL
KEEP THE COOL TEMPERATURES IN PLACE THROUGH THE LONG TERM. A COUPLE
OF SHORT WAVE TROUGHS DROP SOUTH ACROSS THE REGION FROM MONDAY NIGHT
THROUGH WEDNESDAY...RESULTING IN AT LEAST SOME SMALL RAIN CHANCES.
WILL PROBABLY NEED HIGHER CHANCES AT SOME POINT DURING THAT TIME
FRAME...BUT HARD TO PIN DOWN THE TIMING JUST YET.

IF YOU ARE LOOKING FOR WARMER WEATHER...IT MAY BE SHOWING UP LATER
NEXT WEEK AS THE UPPER PATTERN ALLOWS RIDGING TO MOVE IN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 632 AM CDT THU APR 28 2016

SLOW MOVING UPPER LEVEL LOW PRESSURE WILL MEANDER THROUGH NORTHERN
IOWA INTO SOUTHERN WISCONSIN BY TONIGHT...DELIVERING CONTINUED
BANDS OF SHOWERS AT TIMES. AT THE MOMENT...SEEING A BREAK IN
ACTIVITY WITH SOME DRIER AIR ROTATING IN FROM THE SOUTH...WHICH
MAY ALLOW FOR A PERIOD OF SOME DRIZZLE SOUTH OF THE TAF SITES
WHILE DRIER AIR FOR KRST AND KLSE HOLDS CEILINGS A LITTLE HIGHER
IN MVFR TO LOW END VFR RANGE. IT DOES APPEAR THAT DEEPER MOISTURE
WILL ROTATE BACK IN LATER TODAY INTO THIS EVENING...WITH A FEW
MORE PERIODS OF SHOWERS...BEFORE LOSS OF MOISTURE TAKES PLACE BY
LATE EVENING AND JUST AFTER MIDNIGHT WITH THE LOW DEPARTING. THAT
SHOULD BRING AN END TO PRECIPITATION AND ALLOW FOR CEILINGS TO
LIFT BACK TO VFR LEVELS EVERYWHERE. WITH THAT SAID...ANY SMALL
AMOUNT OF CLEARING COMBINED WITH LIGHT WINDS TONIGHT COULD ALLOW
FOR QUICK FOG/STRATUS DEVELOPMENT. FOR THE MOMENT...IT APPEARS
THAT ENOUGH CLOUD COVER WILL STICK AROUND TO PREVENT THAT FROM
HAPPENING...BUT IF CLOUDS DO DEPART...LIFR VISIBILITY IS QUITE
POSSIBLE FOR BOTH SITES IN SOME THICKER FOG.

&&

.HYDROLOGY...
ISSUED AT 332 AM CDT THU APR 28 2016

WATER LEVELS ALONG THE MISSISSIPPI RIVER WILL BE RISING OVER THE
NEXT SEVERAL DAYS. AT THIS TIME...IT APPEARS THAT CRESTS WITHIN
2-5 FEET OF FLOOD STAGE ARE EXPECTED DURING THE FIRST WEEK OF MAY.
THOSE WITH INTERESTS OR CONCERNS ALONG THE RIVER SHOULD KEEP AN
EYE ON WATER LEVELS AND THE LATEST FORECAST INFORMATION.

&&

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

$$

SHORT TERM...MW
LONG TERM...MW
AVIATION...LAWRENCE
HYDROLOGY...MW


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