000
FXUS63 KMPX 251846
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
146 PM CDT SAT MAY 25 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT SAT MAY 25 2013...UPDATED FOR 18Z TAF
DISCUSSION.

INITIAL SHIELD OF WAA SHOWERS THAT WAS DEPICTED WELL ON 310K
ISENTROPIC SFC ON THE NAM/GFS IS FADING AWAY ACROSS WRN WI AS THIS
BATCH OF FORCING WEAKENS AND DIVES SOUTHEAST. IN ITS WAKE...WE HAVE
WAA AT H85...BUT THE DEEPER MOISTURE HAS PUSHED EAST...SO PRECIP HAS
CUT OFF PRETTY QUICK. WITH THE WAA AND WEAK MOISTURE
TRANSPORT...SHOULD BE ABLE TO GET SOME LIGHT SHOWERS/SPRINKLES
ACROSS MN THIS MORNING...BUT NOT MUCH MORE THAN THAT.

BEST CHANCE FOR RAIN TODAY WILL BE ACROSS SRN MN. WARM FRONT NOW CAN
BE FOUND ACROSS SOUTH CENTRAL NEB INTO NE KAN...WITH A STRONG LLJ
OVERRUNNING IT. THIS HAS GENERATED AN MCS OVER ERN NEB THIS MORNING.
THUNDER STARTING TO INCREASE ACROSS IA AS WELL AS THE LLJ HAS SLOWLY
WORKED EAST. MOST OF THIS THUNDERSTORM ACTIVITY WILL REMAIN SOUTH OF
MN THROUGH THE DAY...BUT ALL HI-RES MODELS SHOW SOME OF THIS
MOISTURE FROM IA SNEAKING UP INTO SOUTH CENTRAL MN THROUGH
MORNING...WHERE SOME HIGH CHANCE/LIKELY POPS ARE CONTINUED THROUGH
THE MORNING HOURS. FOR THE AFTERNOON...PRECIP LOOKS TO SHUT
OFF...BUT WE WILL BE STUCK WITH FAIRLY BROAD CLOUD COVER...WITH THE
ONLY HOPE FOR SOME BREAKS ACROSS THE NE MPX CWA THANKS TO THE
INFLUENCE OF A DRY SFC HIGH THAT WILL BE SPLAYED OUT ACROSS THE
GREAT LAKES. GIVEN THE CLOUD COVER WILL BE A COOL DAY...WITH
TEMPERATURES IN SOUTH CENTRAL MN LIKELY STAYING IN THE 50S THANKS TO
BETTER RAIN CHANCES AND THICKER CLOUD COVER.

FOR TONIGHT...ALL MODELS SHOW ANOTHER ROUND OF CONVECTION RIDING
ALONG NORTH OF THE WARM FRONT...KIND OF LIKE WHAT WE HAVE SEEN
OVERNIGHT TO OUR SOUTHWEST. QUESTION BECOMES HOW FAR NORTH DOES THE
ACTIVITY MAKE IT. CONSENSUS PLACEMENT FROM THE WARM FRONT PLACES IT
BY 12Z SUNDAY MORNING FROM THE BLACK HILLS...DOWN THROUGH
YANKTON...SD AND THEN DOWN TO THE CENTRAL IA/MO BORDER. ONCE
AGAIN...WILL SEE A LLJ OVERRUNNING THIS FRONTAL FEATURE...WHICH
SHOULD GENERATE YET ANOTHER MCS. GIVEN THE FRONTS PLACEMENT TO OUR
SOUTHWEST...BEST CHANCES FOR THUNDERSTORMS TONIGHT WILL BE SOUTH OF
THE UPPER MN RIVER IN SW MN INTO SC MN. FOR TIMING...FAVORED HIGHEST
POPS TO AFTER 6Z...AS CONVECTION SHOULD FIRE THIS EVENING OVER SE
SODAK INTO NE NEB...THEN HEAD TOWARD SW/SC MN. ALL OF THIS ACTIVITY
WOULD BE ELEVATED...SO SEVERE THREAT LOOKS MINIMAL...WITH THE MAIN
IMPACT BEING THE POTENTIAL FOR HEAVY RAIN...AS WE HAVE SEEN THIS
EVENING IN NEB.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT MAY 25 2013

THE LONG TERM PERIOD CONTINUES TO LOOK INCREASINGLY WET AND
STORMY. THIS IS DUE TO THE REGION BEING SANDWICHED BETWEEN A
BUILDING UPPER HIGH ALONG THE EASTERN SEABOARD... WHILE A VERY
DEEP TROUGH PUSHES INTO THE WESTERN HALF OF THE UNITED STATES.
THERE SHOULD BE A ROUND OF CONVECTION PASS ACROSS SOUTHERN MN
SUNDAY MORNING...VERY SIMILAR TO WHAT HAS BEEN ONGOING OVERNIGHT
ACROSS NE/IA. THE STORMS TO OUR SOUTH CURRENTLY HAVE BEEN BASICALLY
SUB SEVERE... BUT VERY EFFICIENT RAIN PRODUCERS... WITH UPWARDS OF
1.75 INCHES OF RAIN IN THREE HOURS. THIS IS THE TREND EXPECTED
SUNDAY MORNING ACROSS SOUTHERN MN... ESPECIALLY THE I-90
CORRIDOR. THEREAFTER... A SIGNIFICANT DIMINISHING TREND IN THE
PRECIPITATION FOR SUNDAY AFTERNOON AND EVENING WITH THE NMM/ARW
WRF/S IN AGREEMENT.

MEMORIAL DAY IS LOOKING A LITTLE WORSE NOW WITH EVEN THE ECMWF
DRIVING A WAVE OF CONVECTION ACROSS THE FA DURING THE DAY AND
EVENING. JUST GENERAL THUNDER INDICATED ON SWODY2 WHICH SEEMS
REASONABLE WITH THE MAIN WARM FRONTAL BOUNDARY MEANDERING FROM THE
CENTRAL PLAINS TO THE LOWER OHIO VALLEY. AGAIN... THE CONCERN WILL
BE LOCALIZED HEAVY RAINFALL. THE DETERMINISTIC RUNS WOULD ALSO
SUGGEST ANOTHER ROUND OF CONVECTION FOR US LATE MONDAY NIGHT AND
TUESDAY MORNING... ESPECIALLY ACROSS SOUTHERN MN.

THIS REPEATING ROUNDS OF POTENTIAL CONVECTION IS DISTURBING WITH
AREAS OF SOUTHERN AND ESPECIALLY SOUTHEAST MN RUNNING WELL ABOVE
NORMAL ON RAINFALL FOR THE MONTH OF MAY. THE THREAT FOR FLASH
FLOODING WILL BE ON THE INCREASE. IT WAS POINTED OUT ON FRIDAY
IN THE WEATHERTALK FROM DR SEELY AT THE UMN THAT SINCE MARCH
1ST...(METEOROLOGICAL SPRING) IT HAS BEEN ONE OF THE WETTEST IN
HISTORY FOR MANY AREAS OF MN. ADD THIS TO THE CIPS ANALOGS
FOR 5 DAYS FROM NOW AND ONE SEES A VERY WET PATTERN ACROSS ALL OF
THE REGION WITH 2 INCHES OF RAINFALL EXCEEDING 30 PERCENT
PROBABILITY WITH EVEN WIDESPREAD 3 INCHES HAVING A 10 PERCENT
PROBABILITY. THIS IS IN ADDITION TO THE RAINS SUNDAY THROUGH
TUESDAY. NOT SURPRISING THEN ARE THE RUN TOTALS FROM THE GFS AND
ECMWF THROUGH NEXT FRIDAY WHICH PAINT THE LANDSCAPE WITH 2 TO 4
INCHES OF RAIN... WITH 4 INCHES OR MORE SOUTH OF US. DIGRESSING
FOR A MOMENT... ONE OF THE MONTHS/YEARS THAT HAS SHOWN UP IN THE
CIPS ANALOGS RECENTLY IS JULY 1993... WITH RECORD FLOODING IN THIS
PART OF THE COUNTRY. A REVIEW FROM NCDC SHOWED LOW PRESSURE ALOFT
OVER THE WESTERN HIGH PLAINS WITH A STRONG SW JET AT 250 MB ACROSS
OUR AREA. THE BERMUDA HIGH HAD PUSHED INTO THE SOUTHEAST UNITED
STATES WITH ORGANIZED 850 MB WINDS FROM THE WESTERN GULF OF MEXICO
TO THE WESTERN GREAT LAKES. HENCE... THE FLOODING POTENTIAL IS A
BIG CONCERN FOR THE WEEK AHEAD AS THE PATTERN IN THE SUMMER OF
1993 MIMICS OUR WEEK AHEAD QUITE WELL.

FINALLY... AND JUST AS IMPORTANT... WILL BE THE THREAT FOR SEVERE
WEATHER NEXT WEEK AS THE WARM FRONT LIFTS NORTH INTO OUR AREA
BEGINNING ON TUESDAY. NOT TOO CONCERN ABOUT SEVERE ON SUNDAY. THE
CHANCE INCREASES SOME ON MONDAY (ISOLATED)...ESPECIALLY IF
AFTERNOON CONVECTION DEVELOPS AS DEEP LAYER SHEAR RISES. THEN FROM
TUESDAY ONWARD THERE IS SEVERE POTENTIAL EACH DAY. THE CIPS
ANALOGS CONTAIN MANY SEVERE REPORTS FOR US FOR THE MIDDLE OF NEXT
WEEK WITH SEVERE PROBABILITIES FROM 15 TO 30 PERCENT FOR THE
ENTIRE FA USING THE TOP 8 ANALOGS. A COLD FRONT MAY MOVE ACROSS
THE FA FROM FRIDAY INTO SATURDAY...DIMINISHING THE SEVERE WEATHER
THREAT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 100 PM CDT SAT MAY 25 2013

REMNANTS OF MCS WHICH PRODUCED MODERATE TO HEAVY AMOUNTS OF
PRECIPITATION OVER MUCH OF NORTHERN IOWA...AND LIGHTER AMOUNTS
ABOVE FAR SOUTHERN MN CONTINUES TO DECREASE IN COVERAGE AND
INTENSITY AS IT TREKS INTO NORTHERN IL. CLOSER TO HOME...LARGE
SWATH OF STRATO-CU CONTINUES TO BLANKET ALL OF THE TAF REGION.
WESTERN HALF OF THIS REGION DEALING WITH MVFR...TO LOW END
MVFR CIGS...WITH VFR CONDITIONS ELSEWHERE. ALTHOUGH IR SATELLITE
CONFIRMING SOME REDEVELOPMENT OF LOWER CIGS OVER EASTERN SODAK
...LOSS OF HEATING BY EARLY THIS EVENING SHOULD GIVE GREEN
LIGHT TO SHORT TERM LOSS OF CIGS OVER KAXN...KSTC...AND KRWF
...WITH REDEVELOPMENT POSSIBLE LATER THIS EVENING AHEAD OF
AREA OF CONVECTION FORMING OVER CENTRAL DAKOTAS AFTER 03Z.
NOTHING VERY SUBSTANTIAL CONCERNING FORCING IN RESPECT TO
CONVECTION DURING THE NEXT 24 HOURS OR SO...SAVE TONIGHT
OVER WEST CENTRAL THROUGH SOUTH CENTRAL MN. WITH THAT SAID
TEMPO GROUPS WILL BE THE RULE AT MOST WESTERN TAF LOCATIONS
WITH INSTABILITY PARAMETERS INDICATING POSSIBLE SHORT TERM
THUNDER AT KRWF. LIGHT TO MDT SE FLOW WILL CONTINUE FOR MUCH OF
THE FORECAST PERIOD. VFR VSBYS WILL BE SEEN INTO SUNDAY AFTN
...MINUS SHORT PERIODS OF MVFR ASSOCIATED WITH POSSIBLE CONVECTION.
VFR CIGS EXPECTED AT ALL AIRPORT LOCATIONS AFTER 15Z.

KMSP...

CONFIDENCE IS NOT HIGH FOR SHOWER ACTIVITY LATER THIS EVENING.
MODERATE THETA E ADVECTION AND VERY POTENT 250MB DIVERGENCE
COUPLETS AFTER 06Z...COULD GENERATE A PASSING SHOWER AT KMSP.
MUCH BETTER BET CONCERNS FAIRLY DRASTIC LOWERING OF VFR TO
MVFR CIGS BY 23Z TIME PERIOD. ACTUALLY HAVE A FAIRLY LARGE
AREA OF LOW MVFR CIGS OVER WEST CENTRAL WI ATTM ADVECTING
IN THIS DIRECTION. HEATING SHOULD ELEVATE CIGS AS THEY PROCEED
EAST. ALTHOUGH CURRENT FORECAST DEPICTS CONTUINUATION OF MVFR CIGS
THROUGH 15Z...THERE IS A POSSIBILITY OF A SHORT TERM BREAK IN
THE CLOUD COVER MENTIONED ABOVE BETWEEN 03Z AND 05Z. AFTER 15Z
MDT SE FLOW AND VFR CIGS AND VSBYS SHOULD BE ANTICIPATED TIL
END OF PERIOD. BETTER CHANCES FOR CONVECTIVE ACTIVITY WILL
BE ENCOUNTERED BY LATE SUNDAY NIGHT.




&&

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

$$

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