[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 160548
SWODY1
SPC AC 160547

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1147 PM CST WED FEB 15 2006

VALID 161200Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS DURING THURSDAY AFTERNOON AND
EVENING ACROSS PARTS OF  THE MID MS/LOWER OH VALLEYS...

...SYNOPSIS...
A POSITIVE TILT LARGE-SCALE TROUGH WILL PERSIST OVER THE ERN
PACIFIC...NORTHWEST AND INTERMOUNTAIN U.S...DOWNSTREAM FROM A LARGE
BLOCKING RIDGE AXIS EXTENDING FROM THE GULF OF ALASKA TO THE
CANADIAN ARCTIC. BAND OF VERY FAST WLY FLOW ALOFT WILL STRETCH FROM
THE WEST COAST TO THE GREAT LAKES/APPALACHIANS...BETWEEN THE
POSITIVE TILT WRN TROUGH AND A BUILDING SUBTROPICAL RIDGE ACROSS THE
SRN GULF OF MEXICO/BAY OF CAMPECHE. A SHORT WAVE TROUGH EMBEDDED
WITHIN THIS FAST FLOW REGIME...AND CURRENTLY MOVING ACROSS THE FOUR
CORNERS REGION...WILL ACCELERATE ENEWD FROM THE HIGH PLAINS TO THE
ERN GREAT LAKES THROUGH EARLY FRIDAY WITH A BAND OF 100-110KT MID
LEVEL FLOW SPREADING FROM THE TX/OK PANHANDLES TO WRN PA DURING THE
FORECAST PERIOD.

STRONG FORCING ASSOCIATED WITH THIS SHORT WAVE IMPULSE AND
ASSOCIATED WIND MAX WILL INDUCE SURFACE CYCLOGENESIS ALONG A FRONTAL
ZONE SITUATED ACROSS SRN HIGH PLAINS. RAPID TRANSLATION OF THE LOW
AMPLITUDE UPPER TROUGH WILL CAUSE THE SURFACE LOW TO QUICKLY REFORM
EWD ACROSS THE MID MS VALLEY...AND THEN TRACK TO THE LOWER GREAT
LAKES REGION THROUGH LATE TODAY WHILE DEEPENING. WITH THE PASSAGE OF
THE INTENSIFYING LOW PRESSURE AREA...A STRONG SURGE OF ARCTIC AIR
WILL SPREAD SEWD FROM THE CNTRL PLAINS TO THE LOWER MS VALLEY.

...AR/SERN MO TO OH VALLEY...
EXPANDING LOW LEVEL MOIST AXIS WAS DEPICTED IN SURFACE OBS AND IR
SATELLITE IMAGERY FROM ERN TX/OK TO SRN MO LATE TONIGHT AND IS
EXPECTED TO CONTINUE TO BE TRANSPORTED NWD THROUGH THE MID MS VALLEY
BY 12Z...AND THEN EWD ACROSS THE LOWER OH VALLEY DURING THE
AFTERNOON. WHILE A FEW ELEVATED TSTMS WILL BE POSSIBLE WITHIN WARM
AIR ADVECTION REGIME NORTH OF THE SURFACE FRONT ACROSS THE MIDWEST
THROUGH THE MORNING...DEVELOPING WARM SECTOR AIR MASS WILL LIKELY
REMAIN CAPPED TO SURFACE-BASED STORMS DUE TO EML INVERSION EVIDENT
IN FORECAST SOUNDINGS ACROSS THE REGION.

LATEST SHORT-TERM GUIDANCE IS IN VERY GOOD AGREEMENT THAT THE
COMBINATION OF SURFACE HEATING AND LARGE SCALE ASCENT AHEAD OF
APPROACHING UPPER TROUGH AND COLD FRONT WILL BE NEARLY SUFFICIENT TO
ELIMINATE CONVECTIVE INHIBITION ACROSS CNTRL/SRN MO...WRN IL...AND
NRN AR BY LATE AFTERNOON. HOWEVER...GUIDANCE ALSO APPEARS TO SUGGEST
THAT STORM INITIATION OCCURS ON OR IMMEDIATELY BEHIND THE SURFACE
COLD FRONT AS IT DEVELOPS EWD/SEWD INTO THESE AREAS BY 21Z. INITIAL
ACTIVITY OVER MO MAY BE UNDERCUT BY THE ADVANCING FRONT AND POSE
ONLY A LIMITED WIND/HAIL THREAT. A BETTER CHANCE FOR SUSTAINED STORM
UPDRAFTS TAPPING WEAKLY TO MARGINALLY UNSTABLE BOUNDARY LAYER AIR
MASS MAY EXIST INVOF SURFACE LOW AND FRONT ACROSS IL/IND INTO EARLY
EVENING. ALTHOUGH PRIMARILY UNIDIRECTIONAL IN NATURE...VERY STRONG
LOW LEVEL SHEAR AND FAST STORM MOTION SUGGESTS SUPERCELLS OR BOWING
LINE SEGMENTS WITH DAMAGING WINDS AND POSSIBLY A BRIEF TORNADO OR
TWO. DEEPENING COLD POOL...STRONG MID LEVEL DRY INTRUSION...AND MID
LEVEL FLOW INCREASING TO 90-100KT...ALL SUPPORT THE POSSIBILITY OF
UPSCALE EVOLUTION INTO A SEVERE SQUALL LINE WITH DAMAGING WINDS
SPREADING  EAST ACROSS THE MIDWEST/LOWER OH VALLEY THROUGH LATE
EVENING.

FARTHER SOUTH...FROM AR TO NRN MS...LARGE SCALE DYNAMICS ASSOCIATED
WITH THE TROUGH AND MID LEVEL JET WILL BE WEAKER THAN ACROSS THE
MIDWEST. HOWEVER...THESE DEFICIENCIES MAY BE OFFSET BY GREATER
BOUNDARY LAYER MOISTURE/CAPE AND FORCED ASCENT ALONG THE ADVANCING
FRONT. A LINEAR MCS WITH WIND AND HAIL POTENTIAL SHOULD DEVELOP
ACROSS THESE AREAS THROUGH AT LEAST LATE EVENING BEFORE LOOSING
INTENSITY AS INSTABILITY AND FORCING GRADUALLY WANE WITH EWD/SEWD
EXTENT.

..CARBIN.. 02/16/2006

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT WERE
DISCONTINUED ON 14 FEBRUARY 2006 AND ARE NOW AVAILABLE
IN THE FOLLOWING PRODUCTS:

   WMO HEADER:       AWIPS ID:
   WUUS01            PTSDY1
   WUUS02            PTSDY2
   WUUS03            PTSDY3

A SERVICE CHANGE NOTICE ...SCN05-39... PROVIDES DETAILS
ON THIS TRANSITION. FOR ADDITIONAL DETAILS SEE THE FOLLOWING
WEB ADDRESS USING LOWER CASE LETTERS:
WWW.NWS.NOAA.GOV/OM/NOTIF.HTM