000
FXUS63 KMPX 181808
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
108 PM CDT SAT MAY 18 2013

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 348 AM CDT SAT MAY 18 2013

TODAY-TONIGHT...BROAD-SCALE RIDGE AXIS JUST E OF THE AREA THIS
MRNG...AND WILL CONTINUE TO SHIFT E WHILE A LARGE BROAD-SCALE
TROUGH SHIFTS E THROUGH THE 4-CORNERS REGION. THOUGH OVERALL
RIDGING HAS SHIFTED E...MINOR BUBBLE RIDGES WITHIN THE DEVELOPING
SW FLOW WILL PREVENT FAIRLY WIDESPREAD PRECIPITATION FROM
DEVELOPING DURG THE DAY TDA. HOWEVER...THAT DOES NOT RULE OUT
ISOLD TO SCATTERED CONVECTION FROM THIS MRNG THROUGH THE DAY TDA.
HAVE ALREADY SEEN A HANDFUL OF SEVERE TSTM WRNGS...INCLUDING SOME
VERIFYING WITH HAIL AS LARGE AS 1.5 INCHES. STORM INTENSITY WILL
GENERALLY STAY ON THE TAME SIDE OF SEVERE THRU MUCH OF THE DAY TDA
WHILE CONDITIONS RAMP UP FOR THE POTENTIAL FOR ISOLD SEVERE TSTMS
LATER THIS EVE AND TNGT. ONE LOW PRES CENTER IDENTIFIED OVER THE
WRN DAKOTAS THIS MRNG WILL WORK IN TANDEM WITH ANOTHER LOW PRES
CENTER OVER WRN NE/KS. AS THE NRN LOW SHIFTS NE...IT WILL HELP
DRAG A WMFNT NE THRU SRN AND CENTRAL MN. THIS WILL NOT ONLY ALLOW
A SURGE OF WARM AIR INTO LOWER MN...PUSHING HIGH TEMPS INTO THE
LOW-MID 80S...BUT ALSO MAINTAIN DEWPOINTS INTO THE 60S. THEN...AS
THE UPPER RIDGE SHIFTS FURTHER TO THE E...MORE PRONOUNCED
MERIDIONAL FLOW WITH LOWERING HEIGHTS WILL ENHANCE LIFT. STEEP
LAPSE RATES ALONG WITH A TONGUE OF MUCH HIGHER INSTABILITY WILL
SURGE INTO WRN MN TNGT...HELPING ENHANCE THE COVERAGE AND
INTENSITY OF TSTMS TNGT. SPC MAINTAINS A SLGT RISK OF SEVERE TSTMS
IN ITS SWODY1...BUT THE TIMING IS STILL A LITTLE UNCERTAIN.
HOWEVER...LOOKING AT THE EVOLUTION OF THE TROUGH AND THE
MAINTENANCE OF RIDGING THRU THE FIRST HALF OF THE DAY...WILL
HIGHLIGHT THIS EVE THRU TNGT AS THE PERIOD WHERE SEVERE TSTMS LOOK
TO OCCUR. MAIN HAZARDS WOULD BE LARGE HAIL AND DMGG WINDS...WITH
ISOLD TORNADOES AS A SECONDARY HAZARD SINCE CONDS ARE LESS
FAVORABLE FOR TORNADOES.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 348 AM CDT SAT MAY 18 2013

THE MORE SIGNFICANT THREAT FOR SEVERE WEATHER AFFECTS THE REGION
SUNDAY AND SUNDAY NIGHT. SOUTHERLY FLOW WILL BE IN PLACE ACROSS
THE AREA AS THE UPPER LEVEL TROUGH DIGS INTO THE SOUTHERN AND
CENTRAL PLAINS. THE SURFACE CYCLONE IS FORECAST TO DEEPEN AS IT
MOVES TOWARD NORTHEAST NEBRASKA BY SUNDAY EVENING. WILL LIKELY SEE
ACTIVITY WANE FROM THE SATURDAY NIGHT CONVECTION OVER THE CWA INTO
SUNDAY MORNING. WITH THE UNSTABLE AIRMASS IN PLACE..REDEVELOPMENT
MAY OCCUR QUICKLY DURING THE DAY. THE FOCUS SHOULD SHIFT WEST
AGAIN IN THE AFTERNOON ALONG THE MAIN SURFACE BOUNDARY NEARER THE
NEBRASKA LOW. A MORE SIGNIFICANT WAVE LIFTS NORTHEAST SUNDAY NIGHT
AS THE UPPER LOW PIVOTS SLOWLY EAST. FORECAST SOUNDING FOR MSP
INDICATES AROUND 2000 J/KG CAPE WITH STEEP MID LEVEL LAPSE RATES
7.5-8 C/KM. 0-6 KM SHEAR VALUES INCREASE TO 35 TO 45 KTS DURING
THE EVENING AS THE WAVE ROTATES NORTHEAST. HAIL AND DAMAGING WINDS
WILL BE THE MAIN THREATS...BUT WILL HAVE TO MONITOR LOCATION OF
SURFACE FRONT AND OCCLUDING LOW LATER INTO THE EVENING FOR ANY
POSSIBLE TORNADO THREAT. MCS DEVELOPMENT WILL LIKELY OCCUR INTO
SOUTHERN MN...WITH HEAVY RAIN ALSO POSSIBLE AS PWAT IS FORECAST TO
EXCEED 1.6 INCHES.

THE OCCLUDED SYSTEM IS FORECAST TO SAG SLOWLY TO THE SOUTHEAST
MONDAY INTO TUESDAY. WILL LIKELY STILL MAINTAIN A THUNDER THREAT
THROUGH THIS PERIOD. COULD SEE SOME STRONG STORMS YET IN THE
EASTERN CWA (MAINLY WISCONSIN) FOR MONDAY AFTERNOON. THIS WILL ALL
DEPEND ON HOW MUCH DAYTIME HEATING AND DESTABILIZATION CAN TAKE
PLACE. AGAIN HEAVY RAIN WILL BE POSSIBLE...WITH WIDESPREAD 1 TO 2
INCHES FORECASTED FROM SUNDAY THROUGH MONDAY NIGHT.

TEMPERATURES WILL COOL BACK TO BELOW NORMAL READINGS TUESDAY
THROUGH THURSDAY...WITH EXTENSIVE CLOUD COVER REMAINING IN THE
AREA. WARMER AND DRIER CONDITIONS SHOULD FOLLOW THEREAFTER AS THE
UPPER LOW EXITS THE AREA.  UPPER LEVEL HEIGHTS/RIDGING ALOFT
DEVELOPS AND THIS SHOULD EXTEND INTO AT LEAST THE FIRST HALF OF
NEXT WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 107 PM CDT SAT MAY 18 2013

MORNING STORMS LEFT BEHIND AN AREA OF MVFR CIGS AND EVEN SOME IFR
VSBYS IN SPOTS FROM WEST CENTRAL MN INTO WISC. THIS WILL HANG ON
FOR ANOTHER HOUR OR TWO AT PLACES LIKE AXN/STC/RNH...WHICH ARE
FARTHER NORTH OF THE WARM FRONT CURRENTLY IN SOUTHERN MN. ANOTHER
ISSUE IS POTENTIAL FOR MVFR FOG TONIGHT IN EASTERN MN AND WISC
WITH RESIDUAL MOISTURE AND SOUTHEAST WINDS. THIRD ISSUE IS
DEVELOPMENT OF STORMS THIS EVENING IN WEST CENTRAL MN PER HOPWRF
AND OTHER SHORT TERM MODELS. NORTHEAST MOVEMENT TO INDIVIDUAL
STORMS BUT OVERALL AREA GRADUALLY TRANSLATES EASTWARD...REACHING
EASTERN MN AND WESTERN WISC 08Z-12Z.

KMSP...DRY WEATHER IN WAKE OF MORNING STORMS. NAM SUGGESTS
REDEVELOPING STORMS IN WESTERN MN REACHING KMSP SHORTLY AFTER 00Z
THIS EVENING BUT MOST SHORT TERM MODELS HOLD OFF UNTIL LATE
TONIGHT. THUS HAVE PRECIP AT KMSP NOT UNTIL 10Z. COULD WELL BE TWO
OR THREE HOURS OF THUNDER BUT HAVE NOT ADDED THAT WITH UNCERTAIN
TIMING. SOME GUSTS POSSIBLE AROUND 20 KTS THIS AFTERNOON PER KMPX
SOUNDING.

/OUTLOOK FOR KMSP/
SUN NIGHT...MVFR CIGS/VSBY. LIKELY SHRA/TSRA WITH CHC IFR. S-SE WINDS 8-12
KTS.
MON...VFR/MVFR CIGS. CHC SHRA/TSRA. S WIND 10-15 KTS.
TUE...VFR/MVFR CIGS. CHC SHRA/TSRA. E-NE WIND 5 KTS.

&&

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

$$

SHORT TERM...JPC
LONG TERM...DWE
AVIATION...TDK