Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 131827
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
127 PM CDT SUN APR 13 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 112 PM CDT SUN APR 13 2014

OVER THE PAST FEW HRS...AN EXPANDING AREA OF RAIN HAS MOVED INTO
FAR SC/SE MN. ACROSS NW IA...SOME OF THE RAIN HAS CHANGED OVER OR
MIXED WITH SNOW SINCE NOON. THIS IS ALSO THE AREA WHERE THE MEAN
WET BULB TEMP LAYER FROM THE SFC TO 1KM WAS NEAR ZERO. THESE
WET BLUB TEMPS ARE QUITE HIGHER ACROSS SC/SE MN...EXTENDING INTO
WC WI THIS AFTN. ANYWHERE FROM +2C TO +6C WET BLUB TEMPS WERE
NOTED IN THOSE AREAS.

THERE HAS BEEN AN ABRUPT/SHARP CUTOFF LINE FROM WHERE THE
EXPANDING AREA OF RAIN/SNOW HAS MOVED INTO SW/SC MN. DUE TO THE
PERSISTENT DRIER AIR BLW 3K FROM THE NORTH...THERE WILL BE A VERY
SHARP CUTOFF FROM WHERE RAIN WILL BE MODERATE TO HEAVY AT
TIMES...TO ONLY SPRINKLES. EVENTUALLY AS WET BULB TEMPS FALL THIS
EVENING...THE CHANGE OVER TO SNOW WILL DEVELOP...ESPECIALLY IN
AREAS WHERE THE PRECIPITATION WILL BE LOCALLY HEAVY AT TIMES.
ALTHOUGH THERE WILL BE PERIODS OF MODERATE...POSSIBLY HEAVY SNOW
AT TIMES...A WARM GROUND AND TEMPS ABV FREEZING THRU THE
EVENING...WILL KEEP SNOWFALL TOTALS LOW. THE BEST CHANCE OF 1 TO 2
INCHES OF WET SNOW WILL OCCUR FROM KAEL TO KRGK TO KEAU. NW OF
THIS LINE...ONLY A SLUSHY ONE HALF INCH OR LESS IS POSSIBLE WHERE
SOME MODERATE SNOW IS POSSIBLE. THE PRECIPITATION SHOULD END
QUICKLY AFTER MIDNIGHT ACROSS SC/SE MN AS WELL AS WC WI. THE WINDS
WILL REMAIN BRISK WITH SUSTAINED WINDS OF 20 TO 30...WITH GUSTS
OVER 40 MPH POSSIBLE THIS EVENING/OVERNIGHT. TEMPS ON MONDAY WILL
LIKELY RISE TO NEAR 40 WHERE SNOW COVER IS POSSIBLE IN SE/SC
MN...TO 40 TO 45 DEGREES ELSEWHERE WITH PARTLY CLOUDY SKIES.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 350 AM CDT SUN APR 13 2014

MONDAY THROUGH TUESDAY NIGHT...TRICKIEST ELEMENT OF THIS PERIOD WILL
CONTINUE TO BE FORECAST TEMPERATURES AS STRONG COLD AIR ADVECTION
CONTINUES MONDAY...BUT GIVES WAY TO WARM AIR ADVECTION AHEAD OF AN
APPROACHING MID-WEEK SYSTEM. THIS PERIOD WILL BE DRY ACROSS THE
AREA AS COLD AND DRY CANADIAN AIR FILLS IN ACROSS THE UPPER
MIDWEST...SO NO CHANGES WERE MADE TO THE POP FORECAST. HIGH
TEMPERATURES MONDAY WERE LOWERED FROM THE PREVIOUS FORECAST. THE
COLDEST 850H TEMPERATURES SHOW GOOD AGREEMENT AMONG THE MODELS IN
ARRIVING DURING THE DAY ON MONDAY. THIS TIME OF YEAR
THOUGH...SOLAR RADIATION WILL STILL ALLOW TEMPERATURES TO WARM AT
LEAST SLIGHTLY DURING THE DAY IN MODEST COLD AIR ADVECTION...WHICH
WILL BE THE CASE MONDAY. STARTING OFF THE DAY IN THE MID 20S...THE
COLD AIR ADVECTION WILL BATTLE RADIATIONAL HEATING AND KEEP
TEMPERATURES IN THE MID TO UPPER 30S FOR HIGHS...BASICALLY 20
DEGREES BELOW SEASONAL NORMALS...AND JUST A COUPLE DEGREES SHY OF
RECORD COLD MAXIMUMS FOR MID APRIL. IN ADDITION TO THE COLD
TEMPERATURES MONDAY...IT WILL BE QUITE WINDY WITH NORTH WINDS OF
15 TO 20 MPH, GUSTING TO 25 MPH...MAKING FOR AN UNPLEASANT SPRING
DAY. WE`LL START TO SEE THE CORE OF THE COLD MOVE EASTWARD BY
TUESDAY...BUT PLENTY OF COLD AIR WILL REMAIN. TEMPERATURE SHOULD
REACH THE 40S...WELL BELOW NORMAL. AN APPROACHING SYSTEM FROM THE
WEST WILL HAVE AN IMPACT ON HOW WARM WE GO TUESDAY AFTERNOON. THE
GFS IS FAST WITH THE SYSTEM...WHICH MEANS IT BRINGS WARM AIR
ADVECTION TO THE FA QUICKER THAN OTHER GUIDANCE. HEDGING AGAINST
THE OUTLIER IN THIS CASE...WITH THE NAM/ECMWF/UKMET IN BETTER
AGREEMENT OF A SLIGHTLY SLOWER AND WEAKER PROGRESSION.

WEDNESDAY AND WEDNESDAY NIGHT...WEDNESDAY TEMPERATURES WILL BE
HIGHLY DEPENDENT ON THE TRACK OF THE SURFACE LOW AND THE
ASSOCIATED WARM FRONT...AS A SHORTWAVE WILL DIVE FROM THE PACIFIC
NORTHWEST TUESDAY INTO WEDNESDAY. THERE HAS BEEN SOME SIGNIFICANT
DISAGREEMENT BETWEEN THE GFS/ECMWF IN HANDLING THIS SYSTEM AND
PHASING WITH A NORTHERN TROUGH. DIFFERENCES STILL REMAIN...BUT THE
GFS HAS SHIFTED ITS AXIS OF HEAVY PRECIPITATION ACROSS CENTRAL
MINNESOTA...MORE IN LINE WITH BOTH THE EC AND NAM. THE GFS
INDICATES QUITE A BIT MORE ENERGY WITH THIS SYSTEM THAN THE EC AND
NAM...AND A FASTER PROGRESSION. THE UKMET SIDES WITH THE EC AND
NAM GENERALLY. IT WAS ENCOURAGING TO SEE THE LATEST GFS RUN
RESEMBLE MORE OF AN EC/NAM SOLUTION...DESPITE BEING A LITTLE
FASTER. AREAS FROM ST. CLOUD AND NORTHWARD WILL HAVE THE HIGHEST
POPS AS MODELS ARE CONVERGING ON THE BEST FORCING THERE. AT THIS
POINT...KEPT CONSISTENT WITH A MIX OF RAIN AND SNOW...WHICH IS
DEPENDENT ON THE TIMING AS DAYTIME TEMPERATURES WOULD WARM ENOUGH
TO PRODUCE MAINLY RAIN...WHEREAS NIGHTTIME TEMPERATURES WOULD BE
MORE APT TO ALLOW SNOW DOWN TO THE SURFACE.

THURSDAY THROUGH SATURDAY...ANOTHER CANADIAN HIGH WILL BE ON THE
HEELS OF THE WEDNESDAY SYSTEM...AND POPS WERE DECREASED/TAKEN OUT
FOR THIS PERIOD GIVEN THIS DRY AIR...DESPITE A WELL DEFINED UPPER
TROUGH OVERHEAD. WHILE THE GFS AND EC HAVE POOR AGREEMENT IN
TERMS OF SHORTWAVE PLACE DURING THE REMAINDER OF THE PERIOD...BOTH
AGREE ON A GENERAL WARMING TREND BEGINNING SATURDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1128 AM CDT SUN APR 13 2014

UPSTREAM OBS/CIGS ACROSS NW/CENTRAL MN HAVE REMAINED BETWEEN 1-2K
FOR MOST OF THE MORNING. ALTHOUGH THE CONTINUED CAA AND DRIER
DWPTS SHOULD SLOWLY LIFT THE CIGS DURING THE AFTN...WILL CONTINUE
ON THE CAUTION SIDE WITH MVFR CIGS FOR MOST AREAS THRU
21-22Z...THEN BECOMING VFR OR CIGS RISING ABV 3K BY THE LATE AFTN.
THIS IS BASED ON THE CONTINUED DRIER AIR ADVECTING SOUTHWARD
ACROSS NORTHERN MN THIS AFTN. KRHN/KEAU WILL LIKELY CONTINUE WITH
THE MVFR CIGS THRU THE EVENING...BEFORE LIFTING TOWARD MONDAY
MORNING. KEAU WILL SEE RAIN/SNOW DEVELOP BY 21-23Z WITH MODERATE
RAIN AT TIMES...MIXING WITH SNOW AND CHANGING OVER TO SNOW BETWEEN
00-03Z. SOME MINOR ACCUMULATIONS WILL BE POSSIBLE BEFORE THE SNOW
ENDS IN KEAU BY 3-6Z. WINDS WILL REMAIN FROM THE N/NW THRU THE TAF
PERIOD...WITH THE CONTINUED GUSTY WINDS...BUT NOT AS STRONG BY
MONDAY LATE MORNING.

KMSP...

MAIN SHORT TERM CONCERN REMAINS THE CIGS RISING ABV 1.7K.
UPSTREAM OBS AND THE CONTINUED EXPANSION OF THE PRECIPITATION TO
THE SOUTH HAS ME WONDER IF 21Z IS TOO FAST...AND WHETHER THE
PRECIPITATION MOVES INTO MSP. BASED ON A DRIER FORECAST BLW
3K...AM LEANING TOWARD CIGS RISING TO 2K BY 21Z WITH VCSH. THIS IS
HIGHLY DEPENDENT ON THE EXPANSION OF THE PRECIPITATION FIELD
ACROSS FAR SOUTHERN MN. BY 3Z...MOST OF THE PRECIPITATION...IF TO
MAKES IT TO KMSP...WILL BE SE OF REGION. THEREFORE...CIGS WILL
BEGIN TO RISE TO VFR...BUT THE GUSTY WINDS WILL CONTINUE THRU THE
FORECAST PERIOD FROM THE N/NW.

/OUTLOOK FOR KMSP/

MON EVENING...VFR. NW WINDS LESS THAN 8 KTS.
TUE...VFR. WINDS W 5 TO 10 KT...BECG E/NE BY EVENING.
WED...MVFR WITH RA/SN POSSIBLE. WINDS E 10 TO 20 KTS...BECOMING N-NE.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...FLOOD WATCH THROUGH TUESDAY MORNING FOR WIZ025-026-028.

&&

$$

SHORT TERM...JLT
LONG TERM...SPD
AVIATION...JLT






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