632 
FXUS63 KMPX 211159
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
659 AM CDT SUN JUL 21 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM CDT SUN JUL 21 2013

NORTHWESTERLY FLOW ALOFT WILL CONTINUE TO PRESENT A CHALLENGING 
FORECAST...EVEN IN THE SHORT TERM PERIOD. WHILE THE ACTIVITY 
OVERNIGHT HAS BEEN SPOTTY AT BEST...DO EXPECT EMBEDDED 
IMPULSES...ALBEIT WEAK...TO RENEW ACTIVITY DURING THE DAYLIGHT HOURS 
AS INSTABILITY INCREASES WITH HEATING. ANTICIPATED COVERAGE IS ONLY 
WARRANTING 30-50 PERCENT POPS FOR THE MAJORITY OF THE AREA 
HOWEVER...WITH THE EXCEPTION OF A SMALL AREA OF SOUTH CENTRAL MN 
INTO WEST CENTRAL WI WHERE SEVERAL OF THE MODELS DEPICT A RIPPLE IN 
THE MID LEVEL FLOW TO PASS DURING PEAK HEATING /GENERALLY 15Z-21Z/. 
HAVE INCLUDED 60 POPS FOR SAID TIME FRAME AND AREA. 

REGARDING TEMPERATURES...HAVE TWEAKED FORECAST HIGHS UP A DEGREE OR 
TWO ACROSS WEST CENTRAL MN...AS LATE AFTERNOON SUBSIDENCE SHOULD 
PROVIDE FOR A TAD MORE WARMING. STILL LOOKS LIKE HIGHS FROM THE MID 
70S /WEST CENTRAL WI/ TO LOWER 80S /WEST AND SOUTH CENTRAL MN/. 

TONIGHT...THE HIGH PLAINS SURFACE TROUGH BECOMES MORE OF A PLAYER IN 
THE LOCAL FORECAST...ENTERING WEST CENTRAL MN BY DAYBREAK MONDAY. 
COULD SEE CONVECTION DEVELOPING ALONG THE BOUNDARY OVERNIGHT WHILE 
ANOTHER SHORTWAVE PASSES ACROSS NORTHERN MN...SO HAVE INCLUDED 20-40 
POPS ACROSS THE WESTERN AND NORTHERN PARTS OF THE FORECAST AREA FROM 
06Z-12Z MONDAY. 

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 325 AM CDT SUN JUL 21 2013

SPC UPGRADED THEIR DAY 3 SEE TEXT TO A DAY 2 SLIGHT RISK ACROSS
EASTERN CENTRAL MN AND WEST CENTRAL EARLY THIS MORNING. THERE ARE
DEFINITELY SOME FACTORS POINTING TO THE RISK OF A FEW SEVERE
THUNDERSTORMS ACROSS THE EASTERN HALF OF THE FORECAST AREA.
HOWEVER...THERE IS ALSO STILL A FEW QUESTIONS YET TO BE ANSWERED.
THE MOST NOTABLE MIGHT BE THE TIMING OF THE COLD FRONT WHICH
BASED ON THE ASSORTMENT OF GUIDANCE WE HAVE FROM 12.00/06Z COULD
BE THROUGH MSP/MPX BY THE LATE MORNING OR CLOSER TO 00Z TUESDAY.
AT THIS TIME...WE ARE LEANING TOWARD A SLIGHTLY LATER PASSAGE
SOMETIME IN THE MID-TO-LATE AFTERNOON. THIS SHOULD GIVE US ENOUGH
TIME BUILD GOOD INSTABILITY /2000-3000 J/KG OF ML CAPE OFF THE
21.06 Z NAM FOR EXAMPLE. THERE IS ACTUALLY GOOD MODEL CONSENSUS OF
NEAR 70 DEWPOINTS ACROSS EASTERN PORTIONS OF THE FORECAST AREA BY
MONDAY AFTERNOON. ALSO WORKING IN FAVOR OF SEVERE WEATHER IS THE
850-500MB CROSSOVER WINDS WHICH ARE STRONG ENOUGH IN MAGNITUDE TO
SUPPORT ORGANIZED CLUSTERS OF STORMS AND ARE CLOSE TO SUPPORTING
SUPERCELLS...ESPECIALLY WHEN YOU CONSIDER THE CYCLONICALLY CURVED
HODOGRAPH BEING FORECASTED BY THE NAM/GFS. AS A SIDE NOTE...THE
ONE THING THE TIMING UNCERTAINTY DOES IS BLEED THE POP FORECAST
OVER A MUCH LARGER WINDOW THAN IT NEEDS TO BE...SO IT IS NOT GOING
TO STORM ALL DAY MONDAY. PERHAPS THE DAY SHIFT CAN REDUCE THE POPS
TO A 6-HR OR EVEN 3-HR WINDOW. GOOD LUCK WITH THAT :)

NOW THERE ARE SOME CONCERNS AS WELL...MAINLY IN TERMS OF FORCING
AND STORM COVERAGE. THERE REALLY IS NOT MUCH OF A SHORTWAVE OR
TEMP ADVECTION ALOFT AS THE NEAREST 500 MB HEIGHT FALLS ARE NORTH
OF LAKE SUPERIOR. EVEN WHEN LOOKING AT THE SURFACE WAVE...THE
BULLSEYE OF 5-10 MB MSLP FALLS MOVE ACROSS NORTHERN MN THROUGHOUT
THE DAY...SO WE ARE NOT COMPLETELY SURE HOW MUCH LOW LEVEL
CONVERGENCE THERE WILL BE. ANOTHER CONCERN WOULD BE SOME CAPPING
GIVEN THE STRENGTH OF THE 800-850MB TEMP ADVECTION DURING THE DAY.
WE SHOULD BE GOOD AT 700 MB WITH TEMPS REMAINING BETWEEN 8-10
C...BUT AT LEAST WESTERN MN COULD BE UNDER A 19-22 C WARM BUBBLE.
HOWEVER...THE EASTERN FORECAST AREA STAYS COOLER LONGER AND WE DO
NOT SEE A FORMIDABLE CAP AT THIS TIME IN THE FORECAST SOUNDINGS. THE
UPPER JET/JETS ARE CLOSE TO A COUPLED JET STRUCTURE...WHICH WOULD
BE VERY GOOD...BECAUSE WE COULD EVACUATE SOME AIR ALOFT.
HOWEVER...I WONDER IF THE JETS ARE TOO FAR APART TO GET COUPLING.
OVERALL...THE SLIGHT RISK SEEMS REASONABLE AT THIS POINT AND LOOKS
LIKE IT IS DRAWN ON THE GRADIENT BETWEEN THE BETTER FORCING AND
THE INSTABILITY.

BEYOND MONDAY...THE HIGH BUILDS IN AND LOOKS LIKE THE AREA WILL
REMAIN COOL AND DRY UNDER NORTHWEST FLOW BETWEEN RIDGING WEST AND
TROUGHING EAST THROUGH AT WEDNESDAY. MORE SHORTWAVE ENERGY COULD
MAKE IT AS FAR EAST AS MN BY THURSDAY MORNING AS THE LONG WAVE
RIDGE FLATTENS SLIGHTLY. THUS...YOU WILL NOTICE A RETURN OF PRECIP
CHANCES LATE IN THE WEEK. DO NOT HANG YOUR HAT ON THIS AND THE
REST OF THE POPS IN THE EXTENDED...LOW CONFIDENCE AT THIS POINT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 700 AM CDT SUN JUL 21 2013

NORTHWEST FLOW ALOFT WILL FOSTER WIDELY SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS CENTRAL/SOUTHERN MN AND WEST
CENTRAL WI TODAY. UNFORTUNATELY THE ACTIVITY WILL NOT BE VERY
ORGANIZED THIS MORNING...SO VICINITY MENTION IS MOST APPROPRIATE.
AS INSTABILITY INCREASES WITH DAYTIME HEATING...WILL LIKELY SEE
COVERAGE OF STORMS INCREASE THIS AFTERNOON. HAVE INCLUDED PROB30
GROUPS FOR NOW. OTHERWISE....SOUTHEAST WINDS AT 5 TO 10 KTS
GRADUALLY VEER TO SOUTH/SOUTHWESTERLY OVERNIGHT INTO MONDAY
MORNING AS THE FRONT APPROACHES. COULD ALSO SEE SOME LIGHT FOG AT
KRNH AND KEAU OVERNIGHT WITH VERY LIGHT WINDS. 

KMSP...
SCATTERED SHOWERS AND THUNDERSTORMS WILL NECESSITATE THE INCLUSION
OF A PROLONGED VCSH MENTION...WITH AN AFTERNOON/EVE PROB30.
ATTENDANT CONDITIONS SHOULD BE MOST VFR...WITH THE LOWEST CLOUD
DECK AROUND 4KFT. 

/OUTLOOK FOR KMSP/

MONDAY...VFR. MVFR POSSIBLE WITH A CHANCE OF SHRA/TSRA. WINDS S 5
TO 10 KT BECOMING SW IN THE MORNING THEN SHIFTING NW 10 KTS AFTERNOON.

MONDAY NIGHT...VFR. MVFR VISIBILITIES POSSIBLE LATE. WINDS NW 5
TO 10 KT.

TUESDAY...VFR. WINDS N 5 TO 10 KT.

TUESDAY NIGHT...VFR. WIND E 5 KT OR LESS BECOMING SE.
WEDNESDAY...VFR. MVFR LATE WITH A CHANCE OF SHRA/TSRA. WIND LIGHT
AND VARIABLE.

&&

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

$$

SHORT TERM...LS
LONG TERM...CLF
AVIATION...LS