Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 272047
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
347 PM CDT WED APR 27 2016

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 346 PM CDT WED APR 27 2016

CLOUDS WILL STICK AROUND THROUGH THURSDAY EVENING AS THE UPPER LEVEL
SYSTEM SLOWLY MIGRATES EASTWARD. A BAND OF RAIN WILL LIFT NORTHWARD
THIS EVENING AND SLOWLY DISSIPATE...BUT SHOWERS WILL REDEVELOP
OVERNIGHT BEFORE TAPERING OFF THROUGH THE DAY TOMORROW.

EARLY AFTERNOON WATER VAPOR IMAGERY WITH GFS 500MB HEIGHTS AND WINDS
SHOWED A POSITIVELY TILTED SHORTWAVE ACROSS THE CENTRAL CONUS...WITH
AN OCCLUDED STRUCTURE IN THE CLOUD FIELD. A CLOSER LOOK AT THE MASS
FIELDS REVEALED THAT THIS INDEED WAS AN OCCLUDED SYSTEM. THE DRY
SLOT WRAPPING AROUND FROM THE SOUTHWEST TOGETHER WITH THE LATE APRIL
SOLAR RADIATION ALLOWED THE WARM SECTOR OF THE SURFACE LOW TO
QUICKLY REESTABLISH ITSELF THIS AFTERNOON...AND AS A RESULT A FEW
MINI-SUPERCELLS WITH TORNADOES WERE ONGOING ACROSS SOUTHWEST IA.

CLOSER TO HOME A BAND OF MODERATE RAIN WAS SLOWLY LIFTING NORTHWARD
ACROSS THE REGION...BUT THERE WAS NOT ANY INSTABILITY SO THERE IS NO
LIGHTNING WITH THIS BAND OF PRECIPITATION. AS THE UPPER LEVEL
FORCING SLOWLY WANES ACROSS THE REGION THE RAIN SHOULD
DISSIPATE...BUT ADDITIONAL AREAS OF POSITIVE VORTICITY WILL ROTATE
ACROSS THE REGION AND ALLOW SCATTERED SHOWERS TO REDEVELOP DURING
THE OVERNIGHT HOURS. FORECAST SOUNDINGS SHOW LOW LEVEL SATURATION
THROUGH THURSDAY...SO CONTINUED WITH CLOUDY TO MOSTLY CLOUDY SKIES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 346 PM CDT WED APR 27 2016

AN UPPER RIDGE/BLOCKING HIGH OVER SOUTH CENTRAL CANADA WILL BE THE
MAIN INFLUENCE IN THE EXTENDED PERIOD FROM FRI/SAT/SUN AS A SIMILAR
STORM SYSTEM THAT IS AFFECTING THE CENTRAL PLAINS TODAY...MOVES OUT
INTO THE PLAINS LATE THIS WEEK/WEEKEND WITH SIMILAR RAIN SHIELD/AIR
MASS CONSISTENCIES. BASED ON THE STRONGER INFLUENCE OF THE UPPER
RIDGE...MODELS HAVE BEEN SLOWLY DRYING THE AIR MASS ACROSS THE UPPER
MIDWEST FOR FRI/SAT/SUN SYSTEM. WITH A PERSISTENT OR DEVELOPING EAST-
NORTHEAST WIND IN THE BOUNDARY LAYER...UP TO 5K...THIS WILL ERODE
ANY BOUNDARY LAYER MOISTURE FROM MOVING NORTHWARD. THEREFORE...THE
BEST CHANCE OF MEASURABLE RAINFALL WILL OCCUR NEAR THE IOWA/MN
BORDER...WITH LESSER OR NO AMOUNTS IN CENTRAL MN. THIS IS AGAIN
BASED ON THE MAIN INFLUENCE OF THE UPPER RIDGE IN CANADA. IF THIS
RIDGE DECIDES TO WEAKEN OR RETROGRADE TO THE WEST...THIS MAY ALLOW
FOR A WETTER WEEKEND THAN EXPECTED.

IN ADDITION TO THE RAINFALL CHANCES OR LACK THEREOF...THE EAST-
NORTHEAST FLOW WILL KEEP TEMPERATURES FROM RISING TOO MUCH. IT MAY
EVEN BE COOLER THAN FORECAST. EVENTUALLY AS THIS SYSTEM MOVES EAST
ACROSS THE OHIO VALLEY EARLY NEXT WEEK...TEMPERATURES WILL SLOWLY
MODERATE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 112 PM CDT WED APR 27 2016

VFR CONDITIONS WILL TRANSITION TO MVFR AND POSSIBLE IFR AS A BAND
OF LOW CLOUDS AND RAIN LIFT NORTHWARD THIS AFTERNOON...AND SLOWLY
EXIT THE REGION ON THURSDAY. WINDS WILL BE EASTERLY...BUT
GRADUALLY TAKE ON A MORE NORTHERLY COMPONENT AS THE LOW PRESSURE
SYSTEM TRACKS EASTWARD OVERNIGHT.

KMSP...
RAIN ARRIVAL SHOULD BE AROUND 22Z...AND POSSIBLY 21Z. COULD SEE
MVFR VISBYS AND CEILINGS...BUT AT THIS POINT THE EASTERLY WINDS
ARE BRING DRY AIR...WHICH SHOULD KEEP THE CEILINGS ABOVE
1800FT...AND THE VISBYS ABOVE 4 MILES. THE LIGHT RAIN WILL LINGER
OVERNIGHT...BUT SHOULD EXIT THE REGION BY THURSDAY MORNING.

/OUTLOOK FOR KMSP/
FRI...VFR. WIND E AT 05KT.
SAT...VFR. WIND ENE AT 10G20KT.
SUN...VFR. WIND NE AT 10G15KT

&&

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

$$

SHORT TERM...JRB
LONG TERM...JLT
AVIATION...JRB



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