Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 221730
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN ISSUED BY
NATIONAL WEATHER SERVICE LA CROSSE WI
1230 PM CDT TUE JUL 22 2014

.UPDATE...
ISSUED AT 1025 AM CDT TUE JUL 22 2014

|UPDATED TO REMOVE POPS NEAR THE IOWA BORDER AS PRCIPITATION HAS
DISSIPATED. HAVE MADE MINOR TWEAKS TO TEMPS BASED ON CURRENT OBS
AND TRENDS. REST OF FCST UNCHANGED.

UPDATE ISSUED AT 843 AM CDT TUE JUL 22 2014

UPDATE TO EXTEND POPS THROUGH THIS MORNING ACROSS SOUTHERN PORTION
OF FORECAST AREA NORTH OF THE IOWA BORDER. RADAR INDICATES A SMALL
AREA OF SHOWERS AND POSSIBLE THUNDERSTORMS MOVING THROUGH THE
AREA. THIS IS ASSOICATED WITH A WEAK SURFACE TROUGH/SHORTWAVE
MOVING THROUGH THE REGION. IT WILL DISSIPATE BY LATE MORNING OR
MOVE EAST INTO SE MN.  RST OF FCST UNCHANGED.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT TUE JUL 22 2014

SEVERE STORMS DID INDEED BRUSH OUR FAR NORTHERN COUNTIES IN CENTRAL
MN OVERNIGHT. THE ACTIVITY IS NOW IN FAR NORTHERN WI AND MOVING
BRISKLY ENE. A FEW SHOWERS AND ISOLATED THUNDERSTORMS HAVE SPREAD
INTO FAR WEST CENTRAL MN EARLY THIS MORNING. THE COVERAGE IS A
LITTLE MORE WIDESPREAD TO THE WEST OF KFSD. A FEW OF THE CAMS
HAVE SOME LIGHT SHOWER ACTIVITY ACROSS SW MN THROUGH ABOUT 15Z.
THEREFORE...LOW CHANCE POPS WERE INCLUDED FOR OUR SOUTHWEST
COUNTIES. THE BIG CHANGE TODAY WILL BE FLUSHING OUT THE 70+ DEGREE
DEW POINTS. A COLD FRONT CURRENTLY STRETCHES FROM NEAR KDLH THROUGH
KSTC TO KFSD. DEW POINTS HAVE ALREADY DROPPED INTO THE LOWER 60S IN
THE WAKE OF THE FRONT ACROSS WEST CENTRAL MN. THE FRONT WILL MOVE
THROUGH THE TWIN CITIES DURING THE MORNING WITH 75 DEGREE DEW POINTS
FALLING TO AROUND 65 DEGREES BY EARLY THIS AFTERNOON. DEW POINTS
WILL LOWER INTO THE UPPER 60S OVER SOUTH CENTRAL MN THROUGH THE KEAU
AREA BY LATE IN THE AFTERNOON. THE SOUTHERN AND EASTERN FA WILL HAVE
THE HIGHEST APPARENT TEMPERATURES TODAY WITH AROUND 90 DEGREES
FORECAST. IN ADDITION...BREEZY NORTHWEST WINDS WILL OCCUR BEHIND THE
FRONT TODAY WITH SPEEDS FROM 15 TO 25 MPH. HIGH PRESSURE WILL BUILD
IN TONIGHT FROM SOUTH CENTRAL CANADA. DEW POINTS WILL CONTINUE TO
FALL WITH MUCH OF THE FA REACHING THE LOWER TO MIDDLE 50S BY
DAYBREAK WEDNESDAY.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 352 AM CDT TUE JUL 22 2014

THINGS LOOK FAIRLY UNSETTLED THROUGH THE REMAINDER OF THE FORECAST
PERIOD... ALTHOUGH THERE APPEARS TO BE NOTHING PARTICULARLY
SIGNIFICANT IN THE CARDS. THE UPPER LOW CURRENTLY OFF THE BRITISH
COLUMBIA COAST WILL BE OUR PRIMARY PLAYER DURING THIS PERIOD AS IT
MAKES ITS WAY EASTWARD. THE LARGE SCALE FLOW WILL STILL BE QUITE
AMPLIFIED AT THE START OF THE PERIOD... WITH THE AFOREMENTIONED
UPPER LOW JUST OFF THE WEST COAST... RIDGING FROM THE FOUR CORNERS
TO NUNAVUT... AND TROUGHING OVER EASTERN CANADA INTO THE NORTHEAST
CONUS. HOWEVER... THE WESTERN UPPER LOW IS EXPECTED TO PUSH EAST
THROUGH THE UPPER RIDGE DURING THE LATTER PORTION OF THE WEEK AND
INTO THE WEEKEND... THEN MAKE ITS WAY ACROSS OUR AREA BY SUNDAY
BEFORE HELPING TO REINFORCE THE UPPER TROUGH OVER EASTERN NORTH
AMERICA BY EARLY NEXT WEEK. THE GFS AND ECMWF ARE IN GOOD
AGREEMENT ON THIS LARGE SCALE EVOLUTION OF THINGS... AND ARE EVEN
IN REASONABLE AGREEMENT ON MOST OF THE DETAILS... WITH SOME TIMING
DIFFERENCES BEING THE MAIN ISSUES. THE ENSEMBLE GUIDANCE ISN/T NOT
OVERLY DISPERSIVE... LENDING SUPPORT TO THE DETERMINISTIC
SOLUTIONS... SO WILL GENERALLY FOLLOW THE PATH OF LEAST RESISTANCE
AND UTILIZE A GFS/ECMWF CONSENSUS APPROACH.

MILD AND DRY WEATHER SHOULD PREVAIL ACROSS THE AREA WEDNESDAY
THROUGH MOST OF THURSDAY AS NORTHWEST UPPER FLOW PERSISTS AND
SURFACE HIGH PRESSURE DRIFTS ACROSS THE REGION. RETURN FLOW WILL
START OT SETUP BY LATE THURSDAY... WITH DECENT WARM ADVECTION
ADVERTISED BY THURSDAY NIGHT... ALONG WITH THE RETURN OF
CONVECTIVE INSTABILITY AS 850-500MB DIFFERENTIAL THETA-E VALUES
FALL BACK BELOW ZERO. CHANCES FOR PCPN SHOULD STEADILY INCREASE
FROM WEST TO EAST LATE THURSDAY AFTERNOON THROUGH THURSDAY NIGHT.
THE ECMWF MANAGES TO DRY THINGS OUT FRIDAY AND FRIDAY NIGHT...
WHILE THE GFS CONTINUES TO GENERATE PCPN ALONG THE NORTHWEST-
SOUTHEAST ORIENTED BAROCLINIC ZONE ACROSS OUR AREA. THE GFS HAS A
SOMEWHAT BETTER DEFINED SHORTWAVE MOVING THROUGH THE NORTHERN
PLAINS INTO OUR AREA DURING THAT TIME FRAME... WHICH IS AIDING ITS
MORE BULLISH OUTLOOK ON PCPN. AT THIS POINT IN TIME... CERTAINLY
CAN/T DISCOUNT THE POSSIBILITY OF A MORE PRONOUNCED LEAD SHORTWAVE
AHEAD OF THE MAIN UPPER TROUGH... SO INCLUDED SOME LOW POPS
THROUGH FRIDAY NIGHT BEFORE ALLOWING FOR SOME DRY AIR TO WORK INTO
THE AREA BY SATURDAY. HOWEVER... ANY RESPITE FROM PCPN SHOULD COME
TO AN END BY SUNDAY AS THE UPPER TROUGH SINKS SOUTHEAST ACROSS THE
AREA... PUSHING A COLD FRONT THROUGH AS IT DOES SO. THE MID-UPPER
LEVEL COLD POOL WILL THEN SINK INTO THE AREA FROM LATER SUNDAY
THROUGH MONDAY... SETTING THE STAGE FOR ADDITIONAL SHRA AND
ISOLATED THUNDER... PARTICULARLY DURING DAYTIME HEATING PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1230 PM CDT TUE JUL 22 2014

MAIN FORECAST CHALLENGE DURING THIS PERIOD IS BAND OF POST-FRONTAL
MVFR CEILINGS THAT EXTENDS FROM NORTHWEST WISCONSIN INTO SOUTHWEST
MINNESOTA. LUCKILY THIS AREA HAS BEEN MOVING SOUTHEAST AND THINING
SOMEWHAT SO EXPECT VFR CONDITIONS TO PREVAIL FOR MN SITES MOST OF
AFTERNOON AND A BIT LATER IN DAY FOR WI SIDE. EITHER WAY VFR
CONDITIONS SHOULD PREVAIL BY EVENING AS HIGH PRESSURE BUILDS
IN...WAVE EXITS TO EAST...AND DRYING AT MOST LEVELS CONTINUES. WINDS
SHOULD ALSO STAY UP ENOUGH TO PREVENT ANY FOG FORMATION...ALTHOUGH
SURFACE RIDGE ACROSS WESTERN MINNESOTA COULD ALLOW A FEW PLACES TO
DECOUPLE SO WILL HAVE TO WATCH FOR PATCHY EARLY MORNING FOG OR
STRATUS.

ON WEDNESDAY DIURNAL CUMULUS EXPECTED WHICH SHOULD FORM EARLIEST ON
WI SIDE OR CLOSER TO IOWA BORDER.

KMSP...MVFR CEILINGS SHOULD CLEAR THIS AFTERNOON GIVING WAY TO VFR
CONDITIONS OVERNIGHT. GUSTY NORTHWEST WINDS /GUSTS TO 18-22KTS/
SHOULD DIMINISH THIS EVENING AS WELL. DIURNAL CUMULUS DECK ON
WEDNESDAY SHOULD REMAIN SCATTERED...VFR.

/OUTLOOK FOR KMSP/

THU...VFR. WINDS SE AT 10KTS.
THU NGT...VFR. MVFR CONDITIONS/TSRA POSSIBLE. WINDS SE 10 KNOTS.
FRI...VFR. MVFR CONDITIONS TSRA. WINDS SSE AT 10-15KTS.
FRI NGT...VFR. MVFR CONDITIONS IN SCT TSRA. WINDS S/SE AT 5-8KTS.
SAT...VFR. WINDS W/NW AT 10-15KTS.

&&

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

$$

UPDATE...99
SHORT TERM...RAH
LONG TERM...TRH
AVIATION...SHEA/ARX



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