Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 232033
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
333 PM CDT THU APR 23 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CDT THU APR 23 2015

PRECIPTATION ONSET ASSOCIATED WITH A SHORTWAVE EJECTING NORTHEAST
OUT OF THE ROCKY MOUNTAINS IS THE PRIMARY FORECAST CONCERN IN THE
SHORT TERM PERIOD.

CLOUDS WILL BE ON THE INCREASE THIS EVENING...WITH MODELS INDICATING
A FAIRLY ROBUST MID LEVEL DECK WILL EXPAND ACROSS THE AREA BETWEEN
06Z AND 12Z. MODELS HAVE CONTINUED TO SLOW DOWN THE TIMING WITH
PRECIP...WHICH MAKES SENSE GIVEN THE DRY AIR IN PLACE AT THE SURFACE
AND LOW LEVELS. THE INITIAL SURGE OF WARM AIR ADVECTION WILL LIKELY
YIELD ONLY VIRGA OR A FEW SPRINKLES ACROSS MOST OF THE FORECAST
AREA...EXCEPT IN CENTRAL MN NORTH OF I-94 AND ALONG THE MN RIVER
VALLEY...WHERE A FEW SHOWERS MAY REACH THE GROUND PRIOR TO DAYBREAK.
THERMAL PROFILES INDICATE A RAIN-SNOW MIX IS POSSIBLE...ALTHOUGH
RATES WOULD LIKELY NOT BE SUFFICIENT TO RESULT IN ACCUMULATIONS.
WILL LIKELY SEE MUCH MORE WIDESPREAD ACTIVITY DEVELOP BETWEEN 12Z
AND 18Z...IN THE FORM OF RAIN...AS BETTER FORCING AND MOISTURE
ADVECTION EXPAND INTO THE AREA WITH THE APPROACHING TROUGH. RAINFALL
AMOUNTS GENERALLY IN THE ONE TO TWO TENTHS OF AN INCH RANGE ARE
EXPECTED.

TEMPERATURES TONIGHT SHOULD REMAIN ELEVATED IN THE UPPER 30S AND
LOWER 40S ACROSS THE WEST GIVEN THE INCREASE IN CLOUD COVER AND
STRONGER WAA. WEST CENTRAL WI COUNTIES WILL LIKELY DIP INTO THE 20S
GIVEN CLEARER SKIES AND LOWER DEWPOINTS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU APR 23 2015

THE MAIN LONGER TERM CONCERN REMAINS MOVEMENT OF UPPER TROUGH OVER
THE AREA INTO SATURDAY AND THEN THE WARMING TREND INTO NEXT WEEK.

OVERALL THE 12Z MODELS CONTINUE TO LIFT A FAIR AMOUNT OF MOISTURE
NORTH INTO SOUTHEAST MINNESOTA FRIDAY NIGHT INTO SATURDAY. F-GEN
AND MOISTURE TRANSPORT MAXIMIZES DURING THIS PERIOD...AND WE
SHOULD SEE A DECENT CHANCE OF RAIN...ESPECIALLY OVER THE SOUTHEAST
PORTION OF THE CWA AS THE UPPER LOW SHIFTS OFF TO THE EAST AND
DEEPENS. QPF AMOUNTS OF ONE TENTH TO AT LEAST ONE QUARTER OF AN
INCH STILL LOOKS GOOD. IF THE F-GEN DOES CHANNEL MORE TO THE
SOUTHEAST...SOME HIGHER AMOUNTS WILL BE POSSIBLE...MAINLY FRIDAY
NIGHT TO THE SOUTHEAST.

THE WAVE WILL MOVE SOUTHEAST OF THE AREA ON SATURDAY WITH RAIN
EARLY MAINLY ALONG THE I-90 CORRIDOR...WITH  DIMINISHING POPS
THEREAFTER. BECAUSE OF THE CLOUDS AND RAIN...HIGH TEMPERATURES ARE
EXPECTED TO REMAIN SOME 10 DEGREES BELOW NORMAL THROUGH SATURDAY.
A WARMING TREND IS FORECAST THEREAFTER...INTO MIDWEEK NEXT WEEK
AS THE UPPER LEVEL LOW OVER THE EASTERN CONUS SHIFTS EAST AND THE
WESTERN RIDGE BUILDS INTO THE CENTRAL CONUS. THE GFS AND ECMWF
BRING IN A WEAK FRONT/NORTHERN STREAM SHORT WAVE INTO THE CWA BY
TUESDAY. SOME QUESTION O THE AMOUNT OF MOISTURE ASSOCIATED WITH
THIS SYSTEM...BUT TEMPERATURES IN ITS WAKE ARE EXPECTED TO WARM
THROUGH THE 60S AND INTO THE LOWER AND MIDDLE 70S OVER MUCH OF THE
CWA BY THURSDAY...WHICH WILL BE SOME 10 DEGREES ABOVE NORMAL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1255 PM CDT THU APR 23 2015

BENIGN WEATHER WITH CLEAR SKIES AND VFR CONDITIONS INTO THIS
EVE...THEN MID/HIGH CLOUDS INCREASE FROM THE WEST THIS EVENING.
THE INITIAL SURGE OF MOISTURE/LIFT MAY BE MORE OF A VIRGA
SITUATION OVER CENTRAL MN...WITH ANY PRECIP THAT DOES MAKE IT TO
THE GROUND ACCOMPANIED BY P6SM OR GREATER VSBYS. THEREFORE...HAVE
GONE WITH VCSH MENTIONS INITIALLY AT SOME OF THE
SITES...TRANSITIONING TO PREVAILING -SHRA TOWARD THE END OF THE
PERIOD /18Z/ AS THE BETTER LIFT AND SATURATION ARRIVE. LIGHT
WEST/NORTHWEST WINDS THIS AFTERNOON BECOME VARIABLE AREA-WIDE THIS
EVE...THEN INCREASE TO AROUND OR ABOVE 10KTS OVERNIGHT AS THE
TROUGH APPROACHES.

KMSP...
EXPECTING THE RAIN TO HOLD OFF UNTIL AFTER 12Z AT THIS
TIME. COULD SEE VIRGA WITH A FEW VERY LIGHT SHOWERS AS EARLY AS
12Z...BUT THE MAIN PRECIP SHOULD HOLD OFF UNTIL 18Z.
MVFR APPEARS POSSIBLE WITH THE SHOWERS AFTER 18Z...BUT NOT
CONFIDENT ENOUGH WITH TIMING/PROBABILITY TO INCLUDE AT THIS POINT.

/OUTLOOK FOR KMSP/

SAT...VFR. SLGT CHC -RA. WINDS ENE 10-12 KT.
SUN...VFR. WINDS ENE 5-10 KT.
MON...VFR. WINDS ENE 5 KT.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...LS
LONG TERM...DWE
AVIATION...LS


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