[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 280521
SWODY1
SPC AC 280519

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1119 PM CST MON NOV 27 2006

VALID 281200Z - 291200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS/FORECAST...
WRN U.S. TROUGH WILL CONTINUE TO AMPLIFY AND MOVE EWD TODAY TOWARD
THE ROCKIES AND PLAINS...AS A STRONG NLY MID/UPPER LEVEL JETS
TRANSLATE SEWD ALONG THE WRN PERIPHERY OF THIS FEATURE FROM THE BC
COAST INTO THE WRN STATES.  MEANWHILE...SHORT WAVE TROUGH MOVING
INTO THE CENTRAL/SRN PLAINS PRIOR TO 12Z TODAY WILL TRACK NEWD
WITHIN STRENGTHENING BAND OF SWLY MID/UPPER LEVEL FLOW ALONG ERN
PERIPHERY OF WRN U.S. LONG WAVE TROUGH. 

IN THE LOW LEVELS...PRIMARY SURFACE LOW SHOULD INITIALLY BE LOCATED
OVER SD/NEB AND THEN MOVE NNEWD...REACHING SRN MANITOBA/WRN ONTARIO
BY 12Z WEDNESDAY.  A STRONG ARCTIC FRONT TRAILING THIS LOW WILL
SPREAD E AND S ACROSS THE NRN INTO CENTRAL PLAINS AND UPPER MS
VALLEY.  WARM SECTOR IS EXPECTED TO SPREAD NWD INTO SERN MN/WI...IN
ADVANCE OF THE APPROACHING COLD FRONT...WITH LOWER 50S SURFACE
DEWPOINTS REACHING THAT REGION BY MID-LATE AFTERNOON.

AT 12Z TODAY...CLUSTERS OF TSTMS SHOULD BE ONGOING ACROSS ERN PARTS
OF THE CENTRAL/SRN PLAINS INTO THE MID MO VALLEY...WITHIN ZONE OF
DEEP LAYER ASCENT AND STEEPER MID LEVEL LAPSE RATES ACCOMPANYING THE
CENTRAL/SRN PLAINS SHORT WAVE TROUGH.  A FEW OF THE STRONGER STORMS
MAY BE CAPABLE OF PRODUCING SMALL TO POTENTIALLY MARGINALLY SEVERE
HAIL THIS MORNING...THOUGH THIS THREAT APPEARS TOO MARGINAL TO
INCLUDE SEVERE PROBABILITIES.  AS THE LEAD TROUGH TRACKS TOWARD SRN
CANADA...THIS ONGOING ACTIVITY IS EXPECTED TO LIFT NEWD TO THE WRN
GREAT LAKES REGION BY AFTERNOON...BUT SHOULD TEND TO DECREASE IN
INTENSITY AS IT MOVES AWAY FROM BETTER INSTABILITY.

ADDITIONAL TSTMS ARE PROGGED TO DEVELOP ALONG THE COLD FRONT FROM
SERN NEB TO ERN MN AS THIS BOUNDARY ADVANCES ESE INTO THE MID MO/
UPPER MS VALLEYS BY 29/00Z...WHERE THE RETREATING MOIST WARM SECTOR
WILL HAVE RESULTED IN MARGINAL INSTABILITY.  SOME OF THIS ACTIVITY
MAY BECOME STRONG PRODUCING ISOLATED SEVERE GIVEN FORECAST OF STRONG
VERTICAL SHEAR PROFILES.  THESE STORMS SHOULD SPREAD EWD AND MAY
ALSO DEVELOP SWD ALONG FRONT INTO ERN KS/MO.  SEVERE THREAT APPEARS
TOO MARGINAL TO INCLUDE PROBABILITIES...GIVEN THE EFFECTS OF THE
MARGINAL INSTABILITY.

..PETERS/GRAMS.. 11/28/2006