Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 172040
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
340 PM CDT THU APR 17 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 326 PM CDT THU APR 17 2014

HIGH PRESSURE WAS PUSHING INTO WRN MN THIS AFTERNOON AS THE SFC LOW
THAT BROUGHT US THE HEAVY SNOW YESTERDAY WAS WEAKENING OVER NRN LAKE
MICHIGAN. GIVEN THE FRESH SNOW COVER LIGHT WINDS AND NOTHING MORE
THAN SOME PASSING CIRRUS FOR AT LEAST THE FIRST FEW HOURS
TONIGHT...WE WILL SEE A QUICK DROP IN TEMPS BELOW FREEZING...BUT AS
THE RIDGE MOVES EAST AND SE WINDS BECOME ESTABLISHED...WAA WILL
RESULT IN INCREASING CLOUDS FROM WEST TO EAST THAT WILL PUT A HALT
ON THE TEMP DROP FOR ALL BUT THE ERN AREAS OF THE MPX CWA. THESE
CLOUDS SHOULD ALSO LIMIT ANY FOG POTENTIAL...BUT WE WILL HAVE TO
KEEP AN EYE OUT FOR FOG DEVELOPMENT TONIGHT FOR AREAS IN WI THAT
PICKED UP SNOW LAST NIGHT.

AS MENTIONED ABOVE...THE WAA WILL BE INCREASING TONIGHT...AND THE
MAIN CULPRIT FOR THAT WILL BE A STRENGTHENING LLJ THAT WILL BE
MOVING INTO WRN MN BY FRIDAY MORNING. THOUGH THE DRY LOW LEVELS WILL
INHIBIT PRECIP POTENTIAL...BUT FOLLOWED THE IDEA OF THE
NAM/SREF/HI-RES MODELS WITH AN AREA OF SHOWERS DEVELOPING ON THE
NOSE OF THE LLJ LATE TONIGHT OVER SODAK THAT WILL WORK INTO WEST
CENTRAL MN THIS MORNING. MODEL AGREEMENT IS NOT GREAT ON THIS
SCENARIO HAPPENING...WITH THE ECMWF REMAINING DRY...BUT ENOUGH
SUPPORT IS THERE WITH THE LLJ MOVING IN ALONG WITH THE ASSOCIATED
ISENTROPIC LIFT TO PUT SOME CHANCE POPS IN FOR FRIDAY MORNING OUT IN
WRN MN. DURING THE AFTERNOON...THIS LLJ BEGINS TO WEAKEN...SO NOT
EXPECTING MUCH OF THIS ACTIVITY TO SURVIVE BEYOND 18Z.

TEMPERATURES TOMORROW WILL CERTAINLY BE WARMER AS WE GET ON THE
BACKSIDE OF THE HIGH. HOWEVER...THE WINDS WE WILL BE GETTING WILL BE
COMING OUT OF THE SE...WHICH WILL STILL BRING WITH IT COOLER AIR.
GENERALLY FOLLOWED THE IDEA OF THE MET FOR HIGHS TOMORROW...WITH 40S
FOR AREAS THAT SAW 8+ INCHES OF SNOW AND 50S FOR AREAS THAT DID NOT.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 326 PM CDT THU APR 17 2014

A WARM FRONT WILL MOVE NORTHWARD ACROSS SOUTHERN MN DURING THE
NIGHT WITH SCATTERED SHRA ALONG AND NORTH OF THIS BOUNDARY. THE
BEST CHC OF HEAVIER RAINFALL/SNOWFALL WILL BE WELL NORTH ACROSS
NORTHERN MN WHERE THE BEST FORCING IS EXPECTED. EVENTUALLY A COLD
FRONT WILL SLIDE SE ACROSS THE STATE...AND LIKELY STALLING ALONG
THE IA/MN BORDER. THIS WILL SET THE STAGE FOR SEVERAL ROUNDS OF
SHRA AND POSSIBLY TSRA ACROSS FAR SOUTHERN MN.

THE SLOWER MOVEMENT OF THIS FRONT AND EXPECTED STALL ALONG THE
IA/MN BORDER IS RELATED TO A STORM SYSTEM IN THE GULF OF MEXICO
WHICH IS EXPECTED TO HOLD A RIDGE ACROSS THE OHIO VALLEY.
THEREFORE...LEADING TO A MORE SW FLOW ALOFT AND HOLDING BACK THE
FRONTAL BOUNDARY FROM MOVING SE. INSTABILITY WILL BE GREATEST WELL
SOUTH OF MN...SO ONLY ISOLD TSRA ARE EXPECTED. ANY DEVIATION TO
THIS FRONTAL BOUNDARY WILL CAUSE MORE OR LESS PRECIPITATION ACROSS
SOUTHERN MN.

EVENTUALLY ANOTHER SYSTEM WILL MOVE ACROSS SOUTHERN
CANADA...CAUSING THIS FRONT TO MOVE SOUTHEAST ACROSS THE EASTERN
CONUS. BY MIDWEEK...A LARGE RIDGE IS EXPECTED TO DOMINATE THE
UPPER THE CENTRAL U.S. WHICH MEANS A WARM-UP FOR OUR REGION. IN
ADDTION...UNSETTLED CONDS WILL DEVELOP AS SEVERAL DISTURBANCES
WILL PLAY HAVOC ON CHC/S OF RAINFALL THRU THE END OF NEXT WEEK.
LONGER RANGE MODELS REMAIN FAVORABLE FOR WARMER THAN AVERAGE CONDS
FOR THE LATE WEEK OF APRIL...AND INTO THE FIRST WEEK OF MAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 102 PM CDT THU APR 17 2014

MAIN CONCERN WITH TAFS IS DEPARTURE OF MVFR CIGS THIS AFTERNOON AS
THE SFC LOW CONTINUES TO WEAK OVER THE NRN GREAT LAKES AS HIGH
PRESSURE MOVES IN FROM THE DAKOTAS. 12Z TAFS HAD THINGS TIMED
PRETTY GOOD. ONLY REAL CHANGE WAS TO DELAY THE CLEARING BY A
COUPLE OF HOURS AT WI TERMINALS...BASICALLY KEEPING THINGS IN LINE
WITH THE GFSLAMP...WHICH HAS BEEN TRACKING WELL. AFTER THAT...
ATTENTION TURNS TO END OF TAF AS WAA KICKS INTO HIGH GEAR ON THE
BACKSIDE OF THE HIGH. WILL SEE A HEALTHY BURST OF CLOUDS BETWEEN
6K AND 10K FT...BUT DRY AIR BELOW THAT WILL LIMIT PRECIP
POTENTIAL. FOLLOWED THE IDEA OF THE SREF WITH A BATCH OF SHOWERS
COMING OUT OF NRN SODAK INTO WRN MN FRIDAY MORNING...BUT
CONFIDENCE IN THIS SCENARIO HIGH ENOUGH TO ONLY GO WITH A VCSH AT
THIS POINT. PRESSURE GRADIENT WILL ALSO BE TIGHTENING UP QUICKLY
OUT IN WRN MN BY 18Z FRIDAY...WITH SUSTAINED WINDS UP BETWEEN 15
AND 20 KTS AND GUSTS AROUND 25 KTS EXPECTED BY 18Z OUT AT AXN/RWF.

KMSP...EXPECT MVFR CIGS TO CLEAR MSP BETWEEN 19Z AND 20Z. IF
ANYTHING...WILL BE CLOSER T0 19Z. CONFIDENCE HIGH IN REST OF TAF
AS DRY LOW LEVEL AIR WILL INHIBIT ANY PRECIP REACHING THE GROUND
WITH WAA LATE FRI MORNING INTO THE AFTERNOON. TOWARD THE END OF
THE TAF...WINDS WILL START KICKING UP AS WELL..WITH SE GUSTS TO
BETWEEN 20 AND 24 KTS POSSIBLE AFTER 21Z.

/OUTLOOK FOR KMSP/
SAT...CHC MVFR WITH -SHRA/ISO TS. WINDS SE BCMG SW 10-15 KTS.
SUN...VFR. WINDS NNE 5-10 KTS.
MON...VFR. WINDS W 5-10 KTS.

&&

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

$$

SHORT TERM...MPG
LONG TERM...JLT
AVIATION...MPG




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