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000
FXUS63 KMPX 240909
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
409 AM CDT FRI MAY 24 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM CDT FRI MAY 24 2013

STARTING OUT THIS SHORT TERM PERIOD AT H5 WITH A CLOSED LOW OVER THE
PAC NW...SHARP TROUGH ACROSS ERN NOAM...WITH A RIDGE ACROSS THE
CENTER OF THE CONTINENT. BY SAT MORNING...THE CLOSED LOW WILL HAVE
PUSHED EAST SOME...HELPING NUDGE THE UPPER RIDGE EAST AS THE ERN
TROUGH MOVES TO THE MID-ATLANTIC COAST. AS A RESULT...WILL SEE
UPPER RIDGE AXIS SLIDE FROM ITS CURRENT POSITION UP ACROSS THE
CENTRAL DAKOTAS OVER TO MN/IA BY 12Z SAT...WHICH WILL HELP BRING AN
ABRUPT END TO THE CURRENT DRY SPELL...WHICH TO THIS POINT HAS LASTED
ALL OF ONE DAY.

AT THE SFC...COOL/DRY CANADIAN HIGH CURRENTLY CENTERED DOWN ACROSS
WI WILL HAVE MOVED OVER TO MICH BY SATURDAY MORNING. WITH PAC NW
TROUGH NUDGING EAST...WILL SEE INCREASING LEE THROUGH THROUGHOUT THE
DAY TODAY...WHICH WILL HELP QUICKLY BRING MOISTURE BACK NORTH ACROSS
THE PLAINS.

FOR THE SHORT TERM...BIG QUESTION SURROUNDS PRECIP CHANCES STARTING
THIS AFTERNOON IN THE WEST AND SPREADING EAST ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. HIGH PRESSURE OVER WI HAS PROVIDED US WITH
AN INCREDIBLY DRY ANTECEDENT AIRMASS...AS EVIDENCE BY THE 00Z
SOUNDING FROM KMPX LAST NIGHT WITH A PWAT OF 0.14 INCHES. AS WE GO
THROUGH THE DAY...ISENTROPIC MOISTENING AND LIFT ON THE 305/310K
SFCS REALLY PICKS UP ON THE GFS/NAM THIS AFTERNOON/EVENING. THIS
WILL RESULT IN PRETTY THICK MID-LEVEL CLOUD COVER...ALONG WITH
PRECIP GENERATION ABOVE H7. THE QUESTION THEN BECOMES CAN ANY OF THE
PRECIP MAKE IT TO THE GROUND...AS FORECAST SOUNDINGS FROM THE NAM
SHOW AN INCREDIBLY DRY LAYER OF AIR DOWN AROUND H8 THAT MUST BE
OVERCOME TO GET ANYTHING TO THE SFC. HI-RES CAM REFL FORECASTS SHOW
LIGHT RETURNS MOVING ACROSS MN DURING THE AFTERNOON...PUSHING INTO
WI BY 3Z...THEN MOVING INTO THE FAR ERN CWA BY 6Z ON THIS ISENTROPIC
LIFT. BASED ON THE HI-RES MODELS...THIS BATCH OF SHOWERS WOULD BE
MOST LIKELY ALONG/NORTH OF A BENSON TO RED WING LINE AND WOULD BE
INDICATIVE OF A HIGH POP/LOW QPF SITUATION. THINKING POPS MAY NEED
TO BE INCREASED AND MOVED EAST FASTER NE OF THE BENSON TO RED WING
THROUGH 06Z THAN THE CURRENT GRIDS HAVE...WHILE POPS MAY BE ABLE TO
BE LOWERED THROUGH 6Z SOUTH OF THIS LINE.

AFTER 06Z...PRECIP POTENTIAL SHOULD SHIFT TO SOUTH OF THE BENSON TO
RED WING LINE AS STRONG 925-850 MB MOISTURE TRANSPORT LAYS SE INTO
IOWA. FOR THIS SECOND BATCH OF FORCING...THE ONE OUTLIER IS THE
NAM...WHICH BRINGS THE NOSE OF THIS MOISTURE TRANSPORT INTO SRN
MN...EVERYTHING ELSE KEEPS IT DOWN IN CENTRAL IA. IN ADDITION TO
MOISTURE CONVERGENCE ON THE NOSE OF THIS MOISTURE TRANSPORT...FGEN
IN THE 925-850MB LOOKS TO INCREASE AS WELL...WHICH SHOULD AID IN THE
DEVELOPMENT OF THUNDERSTORMS AROUND 6Z OVER WRN IA THAT THEN TRACK
SE ACROSS IOWA THROUGH THE REST OF THE NIGHT. COULD SEE A COUPLE OF
INCHES OF PRECIPITATION OVERNIGHT IN SOME SPOTS IN IOWA...BUT MAINLY
LIGHT PRECIP IS EXPECTED OVER MN...WITH THE HIGHEST AMOUNTS DOWN
ALONG THE I-90 CORRIDOR. MODEL BLEND FOLLOWED FOR THIS SECOND BATCH
OF PRECIP WAS THE GEM/ECMWF...WHICH BOTH KEEP BULK OF PRECIP ON THE
NOSE OF THE LLJ OVER IOWA.

FOR TEMPERATURES...DID NUDGE HIGHS DOWN A COUPLE OF DEGREES FROM
WHAT WAS INHERITED...WITH HIGHS MAINLY IN THE 60S TODAY. WILL MAKE A
RUN AT 70 ACROSS WRN MN...BUT FEEL DENSE CLOUD COVER BY THE
AFTERNOON SHOULD SLOW DOWN TEMP INCREASES THERE. FOR WRN WI...HELD
HIGHS THERE IN THE LOW 60S AS THEY WILL BE CLOSER TO THE COLD
TROUGH...PLUS WITH LOWS FALLING TO AROUND 30 THIS MORNING...EVEN A
30 DEGREE DIURNAL SWING WOULD HOLD HIGHS TO AROUND 60.

FINAL THING TO WATCH FOR THE AFTERNOON WILL BE THE DEWPOINTS...
ESPECIALLY IN WRN WI. CURRENT DEWPOINT GRIDS FOLLOWED A BLEND OF
BLENDED MOS WITH A MIX DOWN TO H9 ON THE NAM...WHICH RESULTED IN
DEWPS SLOWLY RISING INTO THE MID 30S IN WI THIS AFTERNOON.
HOWEVER...WHEN LOOKING AT A NAM FORECAST SOUNDING FOR EAU THIS
AFTERNOON...THERE IS THAT IMPRESSIVE WEDGE OF DRY AIR FORECAST TO
HANG OUT AT H8. IF THE BOUNDARY LAYER CAN GROW DEEP ENOUGH TO TAP
INTO THAT AIR...THEN ANOTHER DAY WITH DEWPS TUMBLING INTO THE MID
20S CAN BE EXPECTED ACROSS WRN WI...WHICH WOULD HAVE SIGNIFICANT
IMPLICATIONS TO MINIMUM HUMIDITIES THIS AFTERNOON...POSSIBLY
FALLING BACK INTO THE TEENS. WITH THE INCREASING ESE WINDS...THIS
WILL HAVE TO WATCHED FROM THE FIRE WEATHER PERSPECTIVE.


.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 409 AM CDT FRI MAY 24 2013

THE HOLIDAY WEEKEND REMAINS FILLED WITH CLOUDINESS...PRECIPITATION
CHANCES AND COOL HIGH TEMPERATURES. THE THREAT FOR SEVERE THREAT
REMAINS VERY LOW.

RAIN SHOWERS AND ISOLATED THUNDERSTORMS WILL BE ONGOING ACROSS
EASTERN MN AND WEST CENTRAL WI SATURDAY MORNING AS A SHORT WAVE
AND ISENTROPIC LIFT MOVE THROUGH. ALL GUIDANCE IS IN GOOD
AGREEMENT ON DIMINISHING THE RAIN DURING THE AFTERNOON WITH
WESTERN AREAS PERHAPS BEING DRY. AN UPPER RIDGE IS FORECAST TO
AMPLIFY SOME OVER US SATURDAY NIGHT AND SUNDAY...SHUNTING SHORT
WAVE ENERGY COMING IN FROM THE LARGE WESTERN TROUGH TO THE WEST
AND SOUTH OF US. THIS WOULD KEEP THE BEST PRECIPITATION CHANCES
ALONG AND SOUTH OF THE MN RIVER VALLEY... WITH DRY WEATHER OVER
OUR FAR EASTERN WI COUNTIES. THE RIDGE WILL SLIP EAST SUNDAY NIGHT
WITH SEVERAL WAVES OF SHOWERS AND THUNDERSTORMS MOVING THROUGH
MEMORIAL DAY. RAINFALL FROM SATURDAY THROUGH MONDAY MAY AMOUNT TO
SEVERAL INCHES ACROSS NE/IA WHERE THE LOW LEVEL MOISTURE TRANSPORT
IS FOCUSED ALONG A STRENGTHENING WARM FRONT. RAINFALL IN OUR AREA
FOR THE THREE DAY PERIOD SHOULD RANGE FROM A TENTH OF TWO IN WI TO
AN INCH IN SOUTHWEST MN. IT WILL BE COOL THROUGH THE WEEKEND WITH
EXTENSIVE CLOUDINESS AND ESE LOW LEVEL FLOW. HIGHS ON SATURDAY
WILL STRUGGLE TO REACH THE UPPER 50S TO MIDDLE 60S. HIGHS BY
MONDAY SHOULD REACH THE MIDDLE 60S TO LOWER 70S.

THINGS WILL BEGIN TO CHANGE ON TUESDAY AS THE WARM FRONT TO OUR
SOUTH BEGINS TO LIFT NORTH...REACHING OUR FA FOR WEDNESDAY AND
THURSDAY. IT WILL TURN WARMER AND MORE HUMID WITH MUCH BETTER
CHANCES FOR ORGANIZED STRONG TO SEVERE CONVECTION. A CHECK OF THE
CIPS ANALOGS VALID FOR NEXT WEDNESDAY INDICATED WIDESPREAD SEVERE
REPORTS OVER OUR AREA. ONLY ONE OF THE 15 ANALOGS HAD NO SEVERE
REPORTS IN OUR CWA. THE THREAT FOR HEAVY RAINFALL WILL BE ALSO
BE ON THE INCREASE AS WELL WITH PW FORECAST TO BE AT LEAST 2
STANDARD DEVIATIONS ABOVE NORMAL. THE CIPS ANALOGS ALSO POINT TO
THE POTENTIAL FOR SEVERAL INCHES OF RAIN. BY THE WAY... MSP HAS
ALREADY HAD NEARLY 14 INCHES OF PRECIPITATION SO FAR THIS YEAR...
WHICH IS MORE THAN 5 INCHES ABOVE NORMAL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1248 AM CDT FRI MAY 24 2013

HIGH PRESSURE SLIDING INTO WI TONIGHT WILL PROVIDE EXCELLENT
CONDITIONS THROUGH MUCH OF THE DAY FRIDAY...BUT GOING THROUGH THE
DAY...WILL START TO SEE AN AREA OF SHRA/TSRA MOVE EAST THROUGH
THE DAKOTAS. BASED ON MPX SOUNDING LAST NIGHT...AIRMASS OVER THE
MPX AIRSPACE IS VERY DRY...WHICH SHOULD DELAY THE ONSET OF ANY
PRECIP. DID NOT INTRODUCE ANY VCSH UNTIL AFTER 00Z...BUT QUICKLY
SPREAD IT EAST ACROSS MN AS THE LLJ BEGINS NOSING INTO IOWA THIS
EVENING. GIVEN DRY ANTECEDENT CONDITIONS...KEPT CONDS VFR AS IT
WILL TAKE A WHILE TO MOISTEN THE LOW LEVELS...BUT BY 12Z
SATURDAY...PROBABILITIES FOR MVFR OR LOWER CIGS WILL BE INCREASING
PRECIPITOUSLY ACROSS MN. FOR WINDS...HIGH PRESSURE WILL BE SLIDING
OVER TOWARD MICH OVER THE DAY...WITH GRADIENT INCREASING AS A
RESULT. WINDS WILL BE STRONGEST WEST...WEAKEST EAST. BASED ON
SOUNDINGS...EXPECT SOME STRONG SUSTAINED WINDS...WITH MINIMAL
GUSTING. A 16G21KT TYPE DAY LOOKS TO AHEAD FOR WRN MN.

KMSP...CONFIDENCE HIGH IN TAF PARAMETERS UNTIL THE TAIL END OF THE
TAF. AT THIS POINT...KEPT ONLY A VCSH MENTION...THOUGH AT SOME
POINT LATE FRIDAY NIGHT...DO EXPECT THERE TO BE A PERIOD OF
SHRA/ISO TSRA. THIS WOULD BE MOST LIKELY BETWEEN 8Z AND 12Z. AS
FOR CIGS...KEPT THEM VFR...THOUGH CHANCE FOR MVFR...INCLUDING SUB
017 CIGS INCREASES AFTER 8Z SAT.

/OUTLOOK FOR KMSP/
SAT...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10-15 KTS.
SUN...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10-15 KTS.
MON...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY UNTIL 7 AM CDT THIS MORNING FOR MNZ045-052-053-
     063.

WI...FROST ADVISORY UNTIL 7 AM CDT THIS MORNING FOR WIZ014>016-
     023>028.

&&

$$

SHORT TERM...MPG
LONG TERM...RAH
AVIATION...MPG