155
FXUS63 KARX 172351
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
651 PM CDT SAT APR 17 2021
SHORT TERM
(TONIGHT THROUGH TUESDAY)
ISSUED AT 100 PM CDT SAT APR 17 2021
UPPER LEVEL SHORTWAVE TROUGH STILL ON THE DOCKET TO SLIDE SOUTHEAST
ACROSS THE REGION OVERNIGHT SUNDAY THROUGH MONDAY WITH AN ASSOCIATED
COLD FRONT OUT AHEAD OF IT. SLOPING FRONTOGENETIC LIFT ACROSS THE
BOUNDARY, BUT SATURATION HANGS BEHIND THE FRONT (PER BUFKIT
SOUNDINGS/TIME-HEIGHT X-SECTIONS) - THUS, SO DOES THE ASSOCIATED
SHOWER CHANCES. WITH MUCH COLDER AIR FLOWING IN BEHIND THE FRONT,
THERE WILL BE BOTH RAIN AND SNOW CHANCES - ALTHOUGH NOT EXPECTING
MUCH/IF ANY SNOW ACCUM AT THIS TIME.
OF POTENTIALLY MORE CONCERN IS HOW FAR SOUTH THE FRONT SAGS TUE.
ANOTHER PIECE OF UPPER LEVEL ENERGY IS PROGGED TO ROTATE OUT OF THE
SOUTHERN ROCKIES AND RIDE ALONG THE FRONT. MEANWHILE, 300 MB JET
STREAK PROMISES TO ENHANCE THE LIFT VIA THE RIGHT ENTRANCE REGION.
END RESULT IS A PCPN BAND DEVELOPING ALONG/NORTH OF THE FRONT...AND
WITH PLENTY OF COLD AIR IN PLACE...COULD/WOULD BE MOSTLY SNOW. IN
FACT, SOMEONE(S) COULD GET SIGNIFICANT AMOUNTS, ESPECIALLY
CONSIDERING IT'S MID APRIL. THE OPERATIONAL RUN OF THE GFS HOLDS THE
PCPN BAND SOUTH OF THE LOCAL AREA WHILE THE EC BRUSHES PARTS OF NE
IA/SW WI. GFS ENSEMBLE MEMBERS KIND OF A MESS WHILE AROUND 1/2 OF
THE EC'S LIKES THE MORE NORTHWARD SOLUTION. THE 17.12Z NAM FAVORS
THE EC NORTHWARD TAKE TOO. FOR NOW, WILL RUN WITH THE MODEL BLEND
FOR POPS. GOING TO HAVE TO WATCH THIS ONE CLOSE - COULD EASILY SEE A
FEW INCHES...OR NONE. SNOW WOULDN'T STICK AROUND LONG.
MEANWHILE, TEMPS TAKE A TUMBLE STARTING MONDAY, WITH THE COLDEST AIR
SETTLING IN FOR TUE (HIGHS COULD STRUGGLE TO REACH 40). 850 MB TEMPS
AS COLD AS -8 C WITH NAEFS 850 MB TEMP ANOMALIES STILL -1 OR LOWER.
IF YOU GOT AN EARLY START TO SPRING PLANTING, BE READY TO TAKE SOME
PRECAUTIONS - FREEZING TEMPS ARE EXPECTED TUE/WED MORNINGS.
WINTER ISN'T DONE WITH US YET.
LONG TERM
(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 100 PM CDT SAT APR 17 2021
SOMEWHAT MESSY UPPER LEVEL PATTERN FOR THE LATER HALF OF THE NEW
WEEK WITH A VARIETY OF POTENTIAL OUTCOMES VIA THE GFS AND EC - BOTH
IN THE OPERATIONAL RUNS AND THROUGH THEIR RESPECTIVE ENSEMBLE
MEMBERS. THAT SAID, A FEW POINTS THERE SEEMS TO BE SOME AGREEMENT
ON. FIRST IS FOR SHORTWAVE RIDGING/SFC HIGH FOR THU/FRI...WITH A
SLIGHT (TEMPORARY) BUMP UP IN TEMPS. SECOND WOULD BE AN UPPER LEVEL
SHORTWAVE TROUGH THEN DROPPING ACROSS THE AREA SAT/SAT NIGHT
BRINGING SOME PCPN CHANCES (QPF FAIRLY LIGHT). AGAIN, CONFIDENCE ON
THE LOW END IN THE DETAILS BUT WILL LEAN THE FORECAST TOWARD THESE
CURRENT TRENDS.
AS FOR WHEN WE'LL SAY GOODBYE TO THE COOL CONDITIONS - THE 8 TO 14
DAY OUTLOOK FROM CPC DOESN'T BRING MUCH HOPE, KEEPING THE REGION
UNDER THE HIGHER LIKELIHOOD TO STAY COLD. THAT SAID, THE EC AND GFS
(ESPECIALLY THE GFS) SHOWING SIGNS OF RIDGE BUILDING TO THE WEST FOR
THE LAST WEEK OF APRIL - GRADUALLY PUSHING EASTWARD. CROSS YOUR
FINGERS.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 641 PM CDT SAT APR 17 2021
VFR CONDITIONS THROUGH THE PERIOD. A SHORTWAVE WILL BRING
INCREASING MID CLOUDS FL080 THIS EVENING. A STRONGER FRONT WILL
ARRIVE LATER SUNDAY. AHEAD OF THIS STRONGER FRONT SUNDAY, LOOK
FOR HIGH CLOUDS AND MID CLOUDS FL100 TO THICKEN WITH RAIN CHANCES
BEGINNING WITH THE NEXT TAF ISSUANCE. NORTHWEST WINDS DECREASE
TONIGHT WITH THE FLOW BECOMING WEST SOUTHWEST AT KRST. AHEAD OF
THE FRONT, WEST WINDS INCREASE 10 TO 15KTS WITH GUSTS 20 TO 25KTS
AT KRST AS THEY SHIFT TO THE NORTHWEST.
FIRE WEATHER
ISSUED AT 100 PM CDT SAT APR 17 2021
ANOTHER DAY OF DEEP MIXING SUNDAY, UPWARDS OF 800 MB PER NAM12
BUFKIT SOUNDINGS. DEWPOINTS ALREADY RELATIVELY LOW THOUGH, SO IMPACT
OF THE MIXING ON DRYING COULD BE COMPARATIVELY SMALL. THAT SAID,
STILL LOOKING AT WIDESPREAD MIN RHS IN THE 20 PERCENTS DURING THE
AFTERNOON.
IN ADDITION, NOT A LOT OF WIND TO BRING TO THE SURFACE, SO WHILE
WINDS SHOULD BE A FEW TICKS STRONGER ON SUNDAY COMPARED TO TODAY,
GUSTS ONLY IN THE MID TEENS ARE ANTICIPATED.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...ZAPOTOCNY
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