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000
FXUS63 KMPX 122131
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
431 PM CDT SUN MAY 12 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 421 PM CDT SUN MAY 12 2013

THE INFLUENCE OF THE SURFACE RIDGE AXIS WILL PLAY A PART IN ANOTHER
NIGHT OF COLD TEMPERATURES...AT LEAST FOR THE EASTERN HALF OF THE
FORECAST AREA FROM CENTRAL MN INTO WEST CENTRAL WI. DEWPOINTS ARE IN
THE TEENS ACROSS THE MAJORITY OF THE FORECAST AREA THIS AFTERNOON...
WHICH CERTAINLY ILLUSTRATES HOW DRY THE AIRMASS IS. THIS DRY
AIR...IN COMBINATION WITH CALM WINDS AND MOSTLY CLEAR
SKIES...SHOULD LEAD TO SIGNIFICANT RADIATIONAL COOLING FROM NEAR
LAKE MILLE LACS INTO WEST CENTRAL WI NEAR LADYSMITH AND EAU
CLAIRE...WHERE LOWS IN THE MID TO UPPER 20S APPEAR QUITE LIKELY.
BASED UPON THE REASONING DISCUSSED IN THE 345 AM CDT SUNDAY
ISSUANCE OF THE SHORT TERM DISCUSSION...FROST/FREEZE HEADLINES ARE
MOST WARRANTED FOR THE COUNTIES SURROUNDING AND SOUTH OF
INTERSTATE 94 IN WEST CENTRAL WI...WHERE THE GROWING DEGREE DAYS
ARE NOTABLY HIGHER THAN THEIR NEIGHBORING COUNTIES IN WEST CENTRAL
AND NORTHWESTERN WI.

MONDAY BRINGS INCREASING SOUTHERLY FLOW AS A WARM FRONT LIFTS INTO
MINNESOTA. TEMPERATURES WILL RESPOND ACCORDINGLY AS H85 TEMPS
MODERATE TO BETWEEN +10C AND +15C ACROSS WESTERN MINNESOTA.
MEANWHILE...EXPECT HIGH TEMPERATURES TO REACH THE LOWER 80S ACROSS
WEST CENTRAL MN...WITH COOLER UPPER 60S AND LOWER 70S ACROSS CENTRAL
AND SOUTH CENTRAL MN. WISCONSIN LOCALES WILL LIKELY STRUGGLE TO
ECLIPSE 60 DEGREES. THERE IS NOT A LOT OF MOISTURE TO WORK WITH ON
MONDAY...BUT COULD SEE WIDELY SCATTERED SHOWERS ALONG/NORTH OF
INTERSTATE 94 IN CONJUNCTION WITH BETTER MID LEVEL FORCING.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 421 PM CDT SUN MAY 12 2013

MAJORITY OF EFFORT IN LONG TERM WAS SPENT IRONING OUT DETAILS ON
POTENTIAL FOR SEVERE FIRE WEATHER CONDITIONS BOTH MONDAY AND TUESDAY
ACROSS MINNESOTA. AT THIS POINT...TUESDAY LOOKS TO HAVE THE HIGHEST
POTENTIAL FOR TROUBLE...SO HAVE ISSUED A FIRE WEATHER WATCH FOR
THEN. OUR SHORT SPELL OF DRY WEATHER THIS SPRING LOOKS TO COME TO AN
END THIS WEEKEND AS A MORE ACTIVE WEATHER PATTERN SETS IN.

MODELS ARE IN GOOD AGREEMENT THROUGH THE COURSE OF THE WEEK ON THE
TRANSITION TO A MORE ZONAL FLOW ALOFT. FOR THE WEEKEND THE GFS AND
ECMWF SHOW A TROUGH COMING OUT OF THE ROCKIES AND INTO THE
PLAINS...THOUGH SIGNIFICANT DIFFERENCES IN THE DETAILS EXIST IN TERMS
OF PLACEMENT...TIMING...AND STRENGTH OF FEATURES. WHERE THERE IS GOOD
AGREEMENT IS THAT NEXT WEEKEND LOOKS WET...ENOUGH SO THAT EVEN THE
EXTENDED BLENDING PROCEDURE PRODUCED LIKELY POPS FOR DAYS 6 AND 7 OF
THE FORECAST!

TUESDAY CERTAINLY HAS ALL OF THE MAKINGS FOR NEAR RECORD HEAT ACROSS
PARTS OF THE AREA. COLD FRONT WILL BE WORKING ACROSS MN DURING
THE AFTERNOON...WHICH PLACES A WARM TONGUE /WITH 925 MB TEMPS ON
THE ECMWF/NAM/GFS ON THE ORDER OF 25-29C/ FROM SOUTH CENTRAL
MINNESOTA UP INTO EAST CENTRAL MN DURING PEAK HEATING. THESE WARM
TEMPS MORE THAN SUPPORT HIGHS WELL INTO THE 90S FOR MUCH OF THE
MPX MN AREA..OUTSIDE OF THE WRN AND NRN PERIPHERY OF THE MPX CWA.
BASED ON THIS...TOOK EXISTING FORECAST HIGHS TUESDAY AND NUDGED
THEM CLOSER TO THE NAM...WHICH CONTINUES TO OFFER THE EXTREME END
FOR THE POTENTIAL HIGHS ON TUESDAY. DO FAVOR THE HIGH END OF THE
GUIDANCE...SINCE BOUNDARY LAYER WINDS GAIN A FAVORABLE SOUTHWEST
DIRECTION WITH THE NAM MIXING UP TO H7. HAVE SEEN THIS SETUP
BEFORE IN MAY...AND WHEN IT DOES HAPPEN...EVEN THE HIGHEST
TEMPERATURE GUIDANCE OFTEN DOES NOT GO HIGH ENOUGH.

OTHER BIG CHANGE NEEDED TO TUESDAY WAS WITH THE DEWPOINT FORECAST.
FIRST WORD THAT COMES TO MIND WHEN DESCRIBING THE RAW MODEL
DEWPOINTS FOR TUESDAY AFTERNOON IS LAUGHABLE. THE GFS SHOWS 70
DEGREE DEWPS COMING UP THE MS RIVER TOWARD THE TWIN CITIES...VALUES
WHICH ARE LIKELY NOT EVEN CLOSE TO THE BALL PARK! FOR DEWPS
TUESDAY...USED A BLEND OF MIXED DEWPS FROM THE NAM WHEN MIXING TO
H8...AND THE MET GUIDANCE...ABOUT THE ONLY GUIDANCE THAT LOOKS
REMOTELY REASONABLE FOR DEWPOINTS ON TUESDAY. GIVEN UPPER 80 TO MID
90 TEMPS...THESE LOWER DEWPS RESULTED IN FORECAST HUMIDITIES OF 20 TO
30 PERCENT ACROSS MOST OF THE AREA. WINDS LOOK STRONG AS WELL BOTH
AHEAD OF AND BEHIND THE FRONT...AFTER COORDINATING WITH NEIGHBORING
OFFICES AND THE MN DNR...DECIDED TO ISSUE A FIRE WEATHER WATCH FOR
TUESDAY ACROSS ALL BUT SE MN. SEE FIRE WEATHER SECTION FOR
ADDITIONAL DETAILS.

AS FOR POPS...POTENTIAL LOOKS PRETTY MINIMAL WITH THIS SYSTEM.
WARM TEMPERATURES ALOFT THAT WILL HELP PUSH TEMPS INTO THE 90S
WILL ALSO PROVIDE AN EFFECTIVE CAP DURING THE DAY TUESDAY. GIVEN
WAY OVERDONE SFC DEWPS IN THE MODELS...GFS/NAM SB CAPES BETWEEN
3000 AND 4000 J/KG ARE WAY OVER DONE...BUT EVEN WITH THAT...BOTH
MODELS DO NOT GENERATE ANY PRECIP ALONG THE FRONT. EXPECT MAJORITY
OF PRECIP TO BE NORTH OF THE WARM FRONT TUESDAY INTO TUESDAY
NIGHT...KEEPING IT ACROSS NRN WI. TUESDAY EVENING...AS THE H7
TROUGH SWINGS THROUGH...WE DO SEE MID LEVEL TEMPS DROP.
HOWEVER...WITH THE UPPER LOW GOING ACROSS THE INTERNATIONAL
BORDER...THE MPX CWA ENDS UP UNDER A MID LEVEL DRY SLOT. SO AS WE
LOSE THE CAP...DRY AIR ALOFT SHOULD CONTINUE TO KEEP CONVECTION
FROM INITIATING. AS A RESULT...ONLY HAVE A SMALL AREA OF 20 POPS
IN THE NE CWA TUESDAY EVENING...WITH EVERYWHERE ELSE DRY.

WEDNESDAY AND THURSDAY...ZONAL FLOW SETS UP ALOFT. CONTINUED TO
SUPPRESS ANY POPS BOTH DAYS...BUT BOTH THE ECMWF/GFS SHOW A WEAK WAVE
RIPPLING THROUGH THE FLOW ON THURSDAY...WITH SOME LIGHT QPF
GENERATED BY BOTH. SFC FORCING WISE...ECMWF/GFS HAVE A STATIONARY
FRONT DOWN ALONG I-80...SO FAVORED THE IDEA OF KEEPING THINGS
DRY...BUT THAT COULD CERTAINLY CHANGE IN THE NEXT COUPLE OF DAYS.

FOR FRIDAY TROUGH SUNDAY...BETTER FORCING IS IN PLACE TO SUPPORT
INCLUSION OF POPS ANY OF THESE DAYS. DURING THIS PERIOD...GFS
CONTINUES TO RUN OUT AHEAD OF THE ECMWF/GEM WITH REPLACING A
CENTRAL CONUS RIDGE WITH ELEMENTS OF A WRN TROUGH. BEST AGREEMENT
FOR POTENTIAL RAIN COMES FRIDAY NIGHT INTO SUNDAY AS WRN TROUGH
INITIATES CYCLOGENESIS ACROSS THE CENTRAL PLAINS... WITH A FEW
WAVES OF WAA SHOWERS POSSIBLE FRIDAY. THIS PATTERN CERTAINLY
LOOKS FAVORABLE FOR SEVERE WEATHER ACROSS SOME PARTS OF THE
PLAINS. GFS WOULD BE MOST FAVORABLE FOR SEVERE WEATHER IN THE MPX
CWA AS IT BRINGS A WARM FRONT UP TO I-90 ON SATURDAY AHEAD OF A
LOW THAT GOES ACROSS IOWA INTO SE MN SAT NIGHT. THE ECMWF IS
SLOWER WITH THE PROGRESSION OF THE LOW AND ALSO TAKES IT A BIT
FARTHER SOUTH...WITH THE MPX CWA LOCKED IN THE CLOUDS...RAIN...AND
COOLER TEMPERATURES ALL WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1235 PM CDT SUN MAY 12 2013

VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHWEST WINDS WILL
BE A BIT BREEZY THROUGH THE AFTERNOON...WITH INTO THE UPPER TEENS
AND LOWER 20S /KNOTS/. WINDS WILL BECOME LIGHT AND VARIABLE THIS
EVENING...AND THEN TAKE ON A SOUTHERLY DIRECTION BY DAYBREAK
MONDAY. SOUTH TO SOUTHEAST WINDS WILL THEN PREVAIL FOR
MONDAY...WITH GUSTS TO BETWEEN 16 AND 25 KTS EXPECTED AT
NORTHERN/WESTERN SITES /KRWF-KAXN-KSTC/ BY LATE MORNING. HIGH
CLOUDS WILL BE ON THE INCREASE TONIGHT AND MONDAY...WITH HIGH
BASED CUMULUS CLOUD DEVELOPMENT EXPECTED BY 18Z. COULD SEE SOME
ISOLATED TO WIDELY SCATTERED SHOWERS DEVELOPING DURING THE
DAY...BUT MOISTURE/FORCING IS BETTER TO THE NORTH/EAST OF THE
SITES. HIGHER CHANCES WILL ARRIVE AT KEAU AND EVEN KRNH AFTER 18Z MONDAY.

KMSP...
VFR CONDITIONS WITH SUBSIDING WINDS DURING THE EVENING. WINDS
SHIFTING TO SOUTH-SOUTHEASTERLY BY DAYBREAK MONDAY AND INCREASING
TO AROUND 12 KTS BY 17Z.

/OUTLOOK FOR KMSP/
MON NIGHT...VFR. WINDS S AT 5 TO 10 KTS.
TUE...VFR. WINDS SSW AT 15G20KTS.
WED...VFR. WINDS NW AT 10KTS.
THU...VFR. WINDS W AT 5 KTS.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
     EVENING FOR MNZ041>045-047>070-073>077-082>085-091>093.

WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ023-024-026.

     FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ025-027-028.

&&

$$

SHORT TERM...LS
LONG TERM...MPG
AVIATION...LS