Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 251804
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
104 PM CDT MON APR 25 2016

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 315 AM CDT MON APR 25 2016

A BIT OF A PRECIP LETDOWN ACROSS MUCH OF THE AREA OVER THE PAST 24
TO 36 HOURS WITH LITTLE FALLING FOR MOST AREAS...SAVE FOR AREAS
NORTH OF I-94 WHERE A SOLID 1-2 INCHES MATERIALIZED IN THE VICINITY
OF AN ELEVATED WARM FRONT HANGING OUT UP THAT WAY. FARTHER SOUTH
PRECIP HAS BEEN VERY SPOTTY...WITH UPSTREAM CONVECTIVE TRENDS NOT
VERY ENCOURAGING EITHER AS EARLIER WIDESPREAD PRECIP CONTINUES TO
DIMINISH AS IT SIGNIFICANTLY OUTRUNS AVAILABLE INSTABILITY...EVEN IN
THE FACE OF SOME DECENT MID LEVEL DIFLUENCE WORKING ACROSS THE
REGION. THE MAIN FORECAST CONCERN HEADING THROUGH THE DAY REMAINS
PRECIP COVERAGE AND POTENTIAL CONVECTIVE REDEVELOPMENT...WITH SOME
VERY SMALL POTENTIAL FOR A STRONGER STORM OR TWO ACROSS FAR
SOUTHWEST WISCONSIN.

FIRST ISSUE TO DEAL WITH IS REMNANTS OF INCOMING CONVECTIVE LINE
THROUGH MID MORNING. NEAR TERM GUIDANCE TRENDS SNIFFED OUT THE IDEA
OF SIGNIFICANT WEAKENING SINCE LAST EVENING AND INDEED JUST NOT
SEEING MUCH LEFT...WITH MAYBE A SMATTERING OF SHOWERS/ISOLATED
THUNDER WORKING ACROSS THE AREA THROUGH 9 AM OR SO PER RADAR
TRENDS...WITH NOT MUCH IN THE WAY OF AVAILABLE INSTABILITY.
THEREAFTER...CONFIDENCE IS NOT EXACTLY THE HIGHEST REGARDING
ADDITIONAL PRECIP REDEVELOPMENT POTENTIAL THROUGH THE DAY...BUT PER
RECENT TRENDS IT APPEARS WE MAY BREAK OUT INTO SOME SUNSHINE AT
TIMES WITH THE APPROACH OF SURFACE LOW PRESSURE HELPING LIFT A WARM
FRONT BACK NORTH TOWARD THE I-90 CORRIDOR. STILL SOME QUESTION ABOUT
HOW MUCH ADDITIONAL INSTABILITY WE CAN MUSTER...BUT I DO LIKE THE
IDEA OF THE BETTER POTENTIAL FOR SEVERE CONVECTION DEVELOPING OFF TO
OUR EAST INTO SOUTHEAST WISCONSIN AND NORTHERN ILLINOIS FROM MIDDAY
ON INTO EARLY EVENING WHERE MOISTURE TRANSPORT AND INSTABILITY WILL
BE MAXIMIZED BENEATH AN INCOMING STRONGER MID LEVEL JET CORE...
FAVORING THE POTENTIAL FOR SUPERCELL DEVELOPMENT.

CLOSER TO HOME...GUT FEELING IS SOME HEATING WITHIN AN INCOMING DRY
SLOT AND BENEATH THE OPENING UPPER WAVE WILL TEND TO PROMOTE SOME
SHOWER DEVELOPMENT WITH EMBEDDED THUNDER GIVEN MIXED LAYER CAPE
VALUES OF 500-700 J/KG...MAINLY FROM ABOUT I-90 ON NORTH. THIS IS
QUITE SIMILAR TO WHAT OCCURRED UPSTREAM ACROSS NORTH/SOUTH DAKOTA ON
SUNDAY. WEAKENING SHEAR PROFILES THROUGH THE MID LEVELS ALSO
INDICATE PRETTY MUCH NIL SEVERE THREAT. TEMPS TODAY ARE VERY TRICKY
WITH QUESTIONS ABOUT HOW FAR NORTH THE WARM FRONT WILL
LIFT...SIMILAR AGAIN TO SUNDAY...SO SOME BUST POTENTIAL THERE FOR
SURE. HOWEVER...IT DOES APPEAR THAT THE APPROACHING SURFACE LOW WILL
TEND TO LIFT THE WARM FRONT FARTHER NORTH THAN SUNDAY...WITH DEEPER
AFTERNOON MIXING IN THE DRY SLOT SOUTH OF I-90 LIKELY PUNTING TEMPS
WELL INTO THE 70S.

WARMTH COMES TO A CRASHING HALT TONIGHT WITH THE PASSAGE OF THE
LOW...WITH SHALLOW MUCH COOLER AIR BLEEDING IN BENEATH REMNANT WARMTH
ALOFT PROMOTING RAPID STRATUS DEVELOPMENT AS WINDS SHIFT NORTHEAST.
COULD EVEN SEE A TOUCH OF DRIZZLE AT TIMES WITH SOME LIFT THROUGH
THE SATURATED LAYER...WITH LOW CLOUDS LIKELY TO STICK AROUND
THROUGH AT LEAST MIDDAY TUESDAY IF NOT LONGER BENEATH A RATHER SHARP
INVERSION. THAT MAKES FOR A TRICKY TEMP FORECAST...WITH SOME
POSSIBILITY THAT A FEW SPOTS MAY END UP STUCK ONLY IN THE 40S.

NEXT FORECAST HURDLE ARRIVES LATE TUESDAY NIGHT THROUGH THURSDAY
WITH THE NEXT WESTERN TROUGH EMERGING ONTO THE PLAINS AND SPINNING
SLOWLY EASTWARD. STILL WATCHING JUST HOW FAR NORTH PRECIP WITH THIS
FEATURE WILL WORK...ESPECIALLY WITH THE STRONGEST FORCING LOOKING TO
END UP WORK TO OUR SOUTH WITH THINGS WEAKENING CONSIDERABLY AS THE
UPPER WAVE OPENS UP BY WEDNESDAY NIGHT. STILL...WITH HINTS OF A
PERIOD OF BETTER FGEN FORCING AND LOW/MID LEVEL WARM ADVECTION
ASCENT...DO BELIEVE MUCH OF THE AREA WILL END UP WITH MEASURABLE
PRECIP SOMETIME DURING THE MIDWEEK PERIOD...THOUGH THE FAR NORTHERN
EXTENT MAY BE IN JEOPARDY GIVEN STRONGER LOW LEVEL RIDGING AND
PLENTY OF DRY AIR INTACT JUST TO OUR NORTH THROUGH THE PERIOD. IN
ADDITION...IT`S NOT COMPLETELY OUT OF THE QUESTION THAT PRECIP COULD
MIX WITH A LITTLE SNOW OR SLEET NORTH OF I-94 BY LATE WEDNESDAY OR
WEDNESDAY NIGHT  WITH SOME QUITE CHILLY/DRY AIR FEEDING INTO THE
NORTHERN EDGE OF THE PRECIP SHIELD. DEFINITELY A CHANGE FROM RECENT
DAYS!

.LONG TERM...(THURSDAY NIGHT THROUGH SUNDAY)
ISSUED AT 315 AM CDT MON APR 25 2016

LOOKING LIKE A DRY END TO THE WORK WEEK AS LOW LEVEL RIDGING FINALLY
WORKS DOWN INTO THE AREA. IN FACT...PENDING CLOUD TRENDS...COULD SEE
SOME CHANCE FOR FROST DEVELOPMENT FRIDAY NIGHT BEFORE YET ANOTHER
CLOSED LOW IS PROGGED TO MEANDER OUT ONTO THE CENTRAL PLAINS FOR THE
WEEKEND. AS WOULD BE EXPECTED THIS FAR OUT...LOTS OF QUESTIONS ABOUT
HOW FAR NORTH PRECIPITATION WITH THAT FEATURE MAY END UP (NOT A
TERRIBLY DISSIMILAR SETUP FROM OUR MIDWEEK LOW) WITH ADDITIONAL RAIN
CHANCES MORE THAN JUSTIFIED. ONE THING LOOKS MUCH MORE CERTAIN -
TEMPERATURES THROUGH MUCH OF THE FORECAST PERIOD AFTER TODAY SHOULD
REMAIN BELOW NORMAL HEADING INTO EARLY MAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 104 PM CDT MON APR 25 2016

A LOW PRESSUE SYSTEM...CURRENTLY LOCATED JUST WEST OF THE TWIN
CITIES...WILL MOVE EAST ACROSS THE AREA. A MVRF CEILING WILL MOVE
INTO KRST AROUND 25.19Z AND KLSE AROUND 26.05Z. THE CEILINGS AT
KRST WILL THEN LOWER THE CEILINGS TO IFR AT KRST AROUND 26.01Z...
AND IMPROVE BACK TO MVFR BY 26.15Z.

THERE WILL BE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THIS
AFTERNOON...BUT THE CHANCES WERE TOO LOW TO BE INCLUDED IN THE
TAFS.

AS FAR AS THE FOG TONIGHT...THE MODELS ARE NOW SHOWING A
TEMPERATURE AND DEW POINT SPREAD OFR 2 TO 4 DEGREES. DUE TO
THIS...REMOVED THE IFR/MVFR RESTRICTIONS DUE TO FOG.

&&

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

$$

SHORT TERM...LAWRENCE
LONG TERM...LAWRENCE
AVIATION...BOYNE



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