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000
FXUS63 KMPX 220017
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
717 PM CDT TUE MAY 21 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 1235 PM CDT TUE MAY 21 2013

LATEST WATER VAPOR IMAGERY SHOWS OUR BOTTLED UP AND STAGNANT UPPER
AIR PATTERN STILL IN PLACE... WITH THE CUTOFF LOW LINGERING IN OUR
AREA AND ANOTHER CUTOFF OFF THE NORTHWEST COAST. THINGS ARE
STARTING TO SLOWLY MOVE EASTWARD WITH THE PATTERN DE-AMPLIFYING
SOME OVER THE UPCOMING 24 HOURS OR SO. SHRA CURRENTLY ACROSS THE
AREA IS TAKING ADVANTAGE OF WHAT MEAGER INSTABILITY THERE IS ALONG
WITH LOW LEVEL FORCING ARISING FROM THE STATIONARY FRONT LACED
ACROSS THE CENTER OF THE FORECAST AREA. MORE WIDESPREAD LIGHT PCPN
CAN BE FOUND IN THE MID-LEVEL DEFORMATION AND ASSOCIATED AREA OF
FRONTOGENESIS OVER THE NORTH CENTRAL AND NORTHWEST CWFA. WITH
THINGS SLOWLY SHIFTING EAST THROUGH WEDNESDAY... THE GENERAL LOOK
OF ACTIVITY CURRENTLY OVER THE AREA WILL SHIFT ALONG WITH THE
OVERALL LARGE SCALE PATTERN... MEANING SHOWERS WILL PERSIST
THROUGH THE PERIOD... WITH SOME DIURNAL ENHANCEMENT IN THE PSEUDO-
WARM SECTOR AGAIN ON WEDNESDAY... ALTHOUGH IT WILL BE PRETTY MUCH
EAST OF US AT THAT TIME. PCPN NORTH/WEST OF THE SURFACE AND UPPER
LOW WILL REMAIN FAIRLY CONSISTENT OVER TIME... ALONG WITH THE
OVERCAST SKIES. DON/T EXPECT THINGS TO DRY OUT OR CLOUDS TO EXIT
UNTIL WE MOVE BEYOND TOMORROW/S DAYTIME HOURS.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 355 PM CDT TUE MAY 21 2013

OMEGA BLOCK REMAINS IN PLACE OVER MUCH OF CONTIGUOUS US FOR
WEDNESDAY NIGHT INTO THURSDAY. DP/DT INDICATED SLOWER EXIT
OF 50H LOW PRESSURE AREA INTO NORTHERN OHIO VALLEY LATE
WED NIGHT INTO THURSDAY. THUS HAVE SLOWED DECREASE OF POPS
OVER EASTERN THIRD OF FA WEDNESDAY EVENING...VERY EARLY THU
MORNING TO ACCOUNT FOR SAME. NICE SURGE OF CANADIAN POLAR
AIR OVER FA...BEHIND EXITING CUT OFF LOW ANTICIPATED FOR
LATE WEDNESDAY NIGHT INTO FRIDAY MORNING. ANOTHER WARM FRONTAL
BOUNDARY EXPECTED TO IMPACT WESTERN FA BY FRIDAY MORNING. BROAD
AREA OF SFC LOW PRESSURE ASSOCIATED WITH SAME WILL BE SEEN ABOVE
NORTHEASTERN WYOMING BY SAT/12Z...AS 50H CUT OFF LOW NOTED UPSTREAM
OVER WASHINGTON AND OREGON. BOTH GFS40 AND EUROPEAN BRINGING IN
DECENT SWATH OF MOISTURE OVER REGION FOR MUCH OF SATURDAY WITH
BEST FORCING NOTED OVER SW THIRD OF FA. BY SUN/12Z BROAD AREA
OF SURFACE LOW PRESSURE FINALLY TREKS INTO WESTERN SODAK...AND
WESTERN NE BY SUNDAY/12Z TIME PERIOD.

PROXIMITY OF WARM FRONTAL BOUNDARY TO OR OVER PORTIONS OF CWA
SUNDAY-MONDAY WILL DETERMINE TIMING AND EXTENT OF CONVECTIVE
ACTIVITY FOR THIS TIME PERIOD. GFS40 MUCH MORE AGGRESSIVE WITH
INSTABILITY AND PCPN CHANCES SUNDAY INTO MONDAY MORNING AS
OPPOSED TO EUROPEAN. WITH THAT SAID JUST TWEAKED POPS FOR
SUN-TUESDAY PERIOD...WITH HIGHEST POP PROBABILITIES PAINTED OVER
SW AND WEST CENTRAL CWA. SLOW MOVING COLD FRONTAL BOUNDARY
STILL PROGGED OVER FAR WESTERN MN INTO SE SODAK ON WED
AFTN...AND SHOULD PUSH THROUGH MUCH OF FA NEXT WED NIGHT
...AND THEN STALL OVER SOUTHERN WI INTO FAR NORTHERN IA.
ANOTHER MUCH STRONGER SFC CYCLONE FORMS ON THE WESTERN
PORTION OF THIS BOUNDARY LATE THURSDAY...INSURING PROBABLE
CHANCES FOR MOISTURE ENDING THE MONTH OF MAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 700 PM CDT TUE MAY 21 2013

OCCLUDED FRONT LOCATED FROM NEAR KRWF-KSGS-NORTH OF KEAU THIS
EVENING WILL DROP SOUTH OVER WESTERN AREAS AND REMAIN NEARLY
STATIONARY TO THE EAST...AS THE UPPER LOW SHITS SLOWLY TO THE
SOUTHEAST OVERNIGHT. RAIN AREA ON RADAR WILL ALSO REMAIN AND SHIFT
SLOWLY SOUTH DURING THE PERIOD. THIS WILL SPREAD LOW END MVFR INTO
IFR/LIFR CONDITIONS DURING THE NIGHT OVER ALL BUT KEAU DURING THE
NIGHT...AND SPREAD SOUTH AND EAST DURING THE DAY WEDNESDAY. SHOULD
SEE CEILINGS LIFT TO LOWER END MVFR(1500 FT) OR SO INTO THE
AFTERNOON MOST SECTIONS WITH THE LIGHT RAIN ENDING DURING THE
AFTERNOON. MAY SEE CEILINGS LIFT TO 2500 FEET OVER THE NORTHWEST
FORECAST AREA AS DRIER AIR MOVES INTO THE AREA. NORTHEAST TO NORTH WINDS
SHOULD REMAIN MUCH OF THE PERIOD WITH SOME GUSTS DEVELOPING LATER
TONIGHT INTO WEDNESDAY OVER THE AREA. SOUTHWEST WINDS WILL REMAIN
OVER KEAU AREA...AT LEAST INITIALLY UNTIL OCCLUDED FRONT EXITS
LATER TONIGHT.

KMSP...OCCLUDED BOUNDARY REMAINS STATIONARY JUST SOUTH OF THE
FIELD...AND SHOULD REMAIN SO THROUGH THE NIGHT...SHIFTING OFF TO
THE SOUTHEAST. CONFIDENT THIS WILL MAINTAIN NORTHEAST-NORTH WIND
DIRECTION DURING THE PERIOD. SOME GUSTS COULD DEVELOP DURING THE
MORNING WEDNESDAY...AS THE LIGHT RAIN AREA DROPS INTO THE REGION.
EXPECT IFR CIGS...PERHAPS OCNL MVFR EARLY BECOMING IFR AND
REMAINING SO INTO WEDNESDAY MORNING. LIGHT RAIN/DZ EXPECTED
AGAIN...ESPECIALLY AFTER MIDNIGHT INTO MUCH OF THE DAY ON
WEDNESDAY. CIGS EXPECTED TO IMPROVE INTO MVFR CATEGORY WEDNESDAY
AFTERNOON...WITH CLEARING AND DRYING INTO WEDNESDAY NIGHT.

/OUTLOOK FOR KMSP/
WEDNESDAY NIGHT...MVFR CEILINGS EARLY...OTHERWISE VFR CONDITIONS
EXPECTED. NORTHEAST WIND 10 TO 15 KT.
THURSDAY...VFR CONDITIONS EXPECTED. NORTHEAST WIND 5 TO 15 KT.
THURSDAY NIGHT...VFR CONDITIONS EXPECTED. EAST WIND LESS THAN 10
KT BECOMING SOUTHEAST.
FRIDAY AND FRIDAY NIGHT...VFR CONDITIONS EXPECTED. SOUTHEAST WIND
5 TO 15 KT.
SATURDAY...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE
OF SHOWERS AND THUNDERSTORMS. SOUTHEAST WIND 10 TO 20 KT.

&&

$$

SHORT TERM...TH
LONG TERM...AZ
AVIATION...DWE