Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 210901
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
401 AM CDT TUE APR 21 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT TUE APR 21 2015

TODAY AND TONIGHT...SFC ANALYSIS SHOWS A LARGE SFC LOW WITH A 988MB
CENTER OVER ERN ONTARIO PROVINCE THIS MRNG WITH A SFC TROF SNAKING
AROUND ITS PERIPHERY FROM ERN MI INTO NRN IL AND THRU SRN IA/NE. WV
IMAGERY SHOWS A DEEP H5 ROTATING UPR LOW SHIFTED SLIGHTLY WWD OF THE
SFC FEATURE...ALLOWING THE LONGWAVE TROF TO EXPAND AND REMAIN
ANCHORED OVER ERN NOAM THRU TNGT. THESE FEATURES WILL PROMOTE
ISOLD/SCTD -RA/-SN SHOWERS TO DRIFT SEWD THRU THE WFO MPX CWFA FOR
MUCH OF THE DAY INTO TNGT...MAINLY ALONG AND N OF THE I-94 CORRIDOR.
NOT MUCH IN THE WAY OF QPF BUT EVEN TEMPERATURES INTO THE MID-UPR
30S MAY BE SUBJECT TO SNOWFLAKES DUE TO THE DEEP COLD LAYER AND
PROMINENT CAA WITH NW FLOW ALOFT. HIGHS WILL RANGE THRU THE 40S.
THERE WILL AGAIN BE THE CONCERN FOR STRONG WINDS OVER SWRN PORTIONS
OF THE CWFA WHERE CLOUD COVER WILL BE LESS AND CAN BETTER ABLY TAP
INTO STRONG WINDS AT THE TOP OF THE MIXING LAYER. HAVE GONE WITH A
WIND ADVY FOR WRN AND SRN PORTION OF THE CWFA AFTER COLLAB WITH
SURROUNDING OFFICES. WINDS WILL SETTLE DOWN TO 10 MPH OR LESS TNGT
INTO TMRW MRNG. THIS SCENARIO COMBINED WITH DECRG CLOUDS AND
CONTINUED CAA WILL ALLOW FOR TEMPERATURES SO DROP BELOW THE FREEZING
MARK EARLY WED MRNG. LOWS TNGT WILL BOTTOM OUT IN THE MID 20S TO
AROUND 30.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE APR 21 2015

THE PRIMARY WEATHER DRIVER IN THE LONG TERM CONTINUES TO BE THE
DEEPLY AMPLIFIED TROUGH /WHICH IS ESSENTIALLY OVERHEAD RIGHT NOW/
AS IT SETS UP OVER THE NORTHERN GREAT LAKES FROM WEDNESDAY THROUGH
THURSDAY. DURING THIS TIME...WE WILL BE UNDER A PERSISTENT
NORTHWEST FLOW ALOFT...AND CANADIAN HIGH PRESSURE WILL SINK INTO
THE UPPER MIDWEST AT THE SURFACE. SO...DIURNALLY DRIVEN NORTHWEST
WINDS WILL PERSIST BOTH DAYS...GENERALLY 10 TO 20 MPH AT LEAST
WITH SOME GUSTS OVER 20...ESPECIALLY ON WEDNESDAY. THE MAJORITY OF
THE CLOUD COVER ASSOCIATED WITH THE TROUGH WILL HAVE PUSHED TO THE
EAST OF OUR AREA...LEAVING US WITH ABUNDANT SUNSHINE WITH THE
EXCEPTION OF PARTS OF WEST CENTRAL WI WHICH MAY SEE WRAP AROUND
STRATUS SWING THROUGH ON WEDNESDAY.

ONCE FRIDAY COMES...ATTENTION TURNS TO A SHORTWAVE EJECTING OUT OF
THE COLORADO FRONT RANGE. THERE IS ACTUALLY DECENT AGREEMENT
BETWEEN THE GFS/ECMWF/GEM IN HANDLING THIS ENERGY...BUT THE
DETAILS IN HOW FAR NORTH THE PRECIPITATION MAKES IT IS WHERE THE
DIFFERENCE OCCUR. IT LOOKS LIKE AS WE GO THROUGH FRIDAY NIGHT AND
SATURDAY...A SURFACE LOW WILL DEEPEN NEAR KANSAS AND MOVE NEARLY
DUE EAST. THE EC/GEM AGREE WELL WITH THIS ASPECT...WHEREAS THE GFS
TAKES THE LOW SOUTH THROUGH OKLAHOMA TOWARD ARKANSAS. BOTH THE
EC/GEM SPREAD MOISTURE AND WAA LIFT INTO SOUTHERN MN...SO AT LEAST
SLIGHT CHANCE POPS ARE WARRANTED AT THIS TIME. HOWEVER...IF THE
GFS SOLUTION IS ON THE RIGHT TRACK...FRIDAY WOULD REMAIN DRY.

HIGH PRESSURE LOOKS TO BUILD IN AGAIN ON SUNDAY...BEFORE ANOTHER
SHORTWAVE APPROACHES THE REGION SUNDAY NIGHT/MONDAY...AND LIGHT
RAIN WILL BE A POSSIBILITY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1045 PM CDT MON APR 20 2015

SCATTERED SHOWERS /RAIN AND SNOW/ ACROSS CENTRAL MN WILL CONTINUE
FILTERING EAST-SOUTHEAST INTO WISCONSIN. THIS WILL RESULT IN
PROLONGED VCSH MENTIONS GIVEN THE SHOWERS WILL BE
FLEETING...ALTHOUGH ANY IMPACTS WILL BE MINOR/BRIEF. MVFR CIGS
WILL CONTINUE TO OVERSPREAD THE AREA AS WELL...WITH ALL SITES
EXCEPT KRWF SEEING A OVC020-030 DECK PREVAIL THROUGH THE OVERNIGHT
HOURS. IMPROVEMENT TO A LOW-END VFR CIG IS EXPECTED TO OCCUR
DURING THE MID TO LATE MORNING HOURS OF TUESDAY...WITH THE
EXCEPTION OF WI SITES /KRNH AND KEAU/ WHERE PROLONGED MVFR CIGS
AND MORE SHOWER ACTIVITY IS EXPECTED INTO THE AFTERNOON.
WEST/NORTHWEST WINDS STAY GUSTY THROUGH THE PERIOD...WITH ONLY
MINOR NOCTURNAL REDUCTIONS.

KMSP...
EXPECT RAIN/SNOW SHOWERS IN THE VICINITY OF THE SITE TONIGHT. NO
ACCUMULATIONS HOWEVER. BY 15Z TUESDAY...ACTIVITY IS EXPECTED TO BE
TO THE NORTH-NORTHEAST OF KMSP. MVFR CIGS TONIGHT THROUGH 15Z
TUESDAY. WIND GUSTS THROUGH THE NIGHT...INCREASING AGAIN BY LATE
MORNING TUESDAY.

/OUTLOOK FOR KMSP/
WED...VFR. WINDS NW 15G25KTS.
THU...VFR. WINDS NW 10-15KT.
FRI...VFR. WINDS NE 5-10 KT.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY FROM NOON TODAY TO 6 PM CDT THIS EVENING FOR
     MNZ047-048-054>057-064-065-067-073>076-082>085-091>093.

WI...NONE.
&&

$$

SHORT TERM...JPC
LONG TERM...SPD
AVIATION...LS


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