High Risk

[jshetley]

SPC AC 290548

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1248 AM CDT SAT MAY 29 2004

VALID 291200Z - 301200Z

THERE IS A HIGH RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 E
CSM 45 W HUT 35 ENE HLC 20 SW HSI 35 ESE GRI 30 ESE LNK 15 SE FNB 20
SW OJC 40 WSW JLN 25 SSE TUL 35 ESE OKC 40 E CSM.

THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM LTS 35
E GAG 50 SW RSL 25 WSW HLC 30 NNE MCK 25 N BUB 15 E HON 40 NNE ATY
35 WSW STC 30 NNE MKT 30 WSW MCW 10 SE DSM 45 NNE SZL 10 SSW SGF FSM
10 ENE DUA 20 ESE SPS LTS.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 N
CMX 45 SSW IMT 35 SSW RFD 55 NNW POF 45 NNW LIT 25 NW TYR 40 NW HDO
20 NNW DRT 45 ENE P07 55 S BGS 30 S CDS 15 S GAG DDC 35 NNW GCK 30
NE LAA 25 SSW LIC 45 WSW AKO 20 NE AIA 20 NNW PHP 30 SSW P24 80 NW
MOT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 90 SW P07 35 NW BGS
45 ESE AMA 35 SSW LBL 25 NNE EHA 35 S LAA 10 E RTN 30 NNW SAF 30 WNW
GUP 10 NNW GCN SGU 45 NE ELY 50 WSW MLD 20 NW PIH 60 SW 27U 30 S LWS
20 WSW GEG 70 NNW 3TH 30 SSE FCA 10 NNE BZN 25 S BIL 35 WNW MLS 60
NNW GGW.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 65 NNE MQT 45 SSE ESC
10 SW GRR 35 SSE FDY 25 SSW MGW 35 SSW WAL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 NW FMY 35 WNW DAB
30 W JAX 10 NW MGR 25 SW SEM 10 WNW JAN 40 SE SHV 45 NE CLL 30 SSE
AUS LRD.

...THERE IS A HIGH RISK OF SVR TSTMS FROM CENTRAL OKLAHOMA TO SRN
NEBRASKA...

...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK FROM
THE RED RIVER OF SRN OK TO SWRN MN...

...THERE IS A SLGT RISK OF SVR TSTMS FROM SWRN TX TO THE CANADIAN
BORDER...

...A MAJOR SEVERE WEATHER OUTBREAK IS EXPECTED ACROSS MUCH OF THE
PLAINS INTO PORTIONS OF THE MISSISSIPPI VALLEY SATURDAY...INCLUDING
THE LIKLIHOOD OF DAMAGING TORNADOES...

SIGNIFICANT HEIGHT FALLS WILL SPREAD INTO THE PLAINS SATURDAY AS
LONG WAVE TROUGH SHIFTS ACROSS THE ROCKIES INTO THE MID SECTION OF
THE COUNTRY. THIS UPPER LEVEL FEATURE WILL ENHANCE DEEP LAYER
VERTICAL SHEAR ACROSS A BROAD SWATH OF VERY UNSTABLE BOUNDARY LAYER
AIRMASS FROM NRN TX...NWD INTO NEB....AND INTO PORTIONS OF THE ERN
DAKOTAS AND SWRN MN.

EARLY IN THE PERIOD STRONG WARM ADVECTION ON NOSE OF LLJ WILL
UNDOUBTEDLY DRIVE AN EXPANSIVE CLUSTER OF ELEVATED THUNDERSTORMS
ACROSS THE UPPER MS VALLEY REGION. RAPID DESTABILIZATION SHOULD
OCCUR IN THE WAKE OF THIS ACTIVITY ACROSS ERN SD INTO SWRN MN.
DAYTIME HEATING AHEAD OF NRN-MOST SFC LOW IN CENTRAL SD WILL RESULT
IN RENEWED CONVECTIVE DEVELOPMENT...LIKELY IN THE FORM OF SUPERCELLS
BY EARLY AFTERNOON. FORECAST PROFILES INDICATE MORE THAN ADEQUATE
DEEP LAYER SHEAR...STRONG VEERING AND SBCAPE ON THE ORDER OF 2000
J/KG. THERE APPEARS TO BE A SIGNIFICANT SIGNAL FOR POTENTIAL
TORNADIC SUPERCELLS DURING THE AFTERNOON/EVENING HOURS ALONG WARM
FRONT...WWD TO SFC LOW. THIS ACTIVITY SHOULD SPREAD EWD AS COLD
FRONT SHIFTS INTO MN DURING THE OVERNIGHT HOURS.

FARTHER SOUTH...MARITIME BOUNDARY LAYER MOISTURE...SFC DEW POINTS IN
THE LOWER-MID 70S...IS RAPIDLY SURGING NWD ACROSS TX EARLY THIS
MORNING. AT 05Z THIS AIRMASS HAD RETURNED TO THE HILL
COUNTRY...NEAR THE DALLAS/FT WORTH METROPLEX...NEWD INTO SRN AR.
CURRENT INDICATIONS ARE 70S DEW POINTS WILL LIFT ACROSS OK AND KS
AHEAD OF DRY LINE BY PEAK HEATING/CONVECTIVE INITIATION. ALTHOUGH A
LEAD UPPER SHORTWAVE TROUGH WILL LIFT ACROSS THE SRN PLAINS EARLY IN
THE PERIOD...IT APPEARS STRONG HEATING IN THE WAKE OF MID LEVEL
CLOUDS/BROKEN PRECIPITATION WILL OCCUR ALONG THE DRY LINE BY EARLY
AFTERNOON...CREATING A VERY UNSTABLE WARM SECTOR...ON THE ORDER OF
3500-4000 J/KG. CURRENT THINKING IS AFTERNOON HEATING...IN
CONJUNCTION WITH VERY STRONG CONVERGENCE ALONG DRY LINE...WILL PROVE
MORE THAN SUFFICIENT FOR POTENTIALLY EXPLOSIVE SUPERCELL DEVELOPMENT
FROM SOUTH CENTRAL NEB INTO SWRN OK. FORECAST SOUNDINGS STRONGLY
FAVOR TORNADIC DEVELOPMENT AS VERY STRONG LOW LEVEL SHEAR WILL ONLY
INCREASE DURING THE LATE AFTERNOON/EVENING AS LLJ INCREASES IN
EXCESS OF 60KT FROM NERN OK INTO NERN KS. DAMAGING TORNADOES MAY
ACCOMPANY SUPERCELLS THAT TRACK ENEWD ACROSS THE PLAINS TOWARD THE
MS VALLEY REGION DURING THE EVENING HOURS.

WELL AFTER DARK ACTIVITY MAY EVOLVE INTO MULTIPLE COMPLEXES
COMPRISED OF EMBEDDED BOW ECHOES AND SUPERCELLS AS IT TRANSLATES
INTO WRN IA/MO. DAMAGING WINDS AND VERY LARGE HAIL SHOULD BE COMMON
ALONG WITH ISOLATED TORNADOES WELL INTO THE MORNING HOURS.

..DARROW/TAYLOR.. 05/29/2004

[Colin]

No watches or MDs yet...I'm waiting for things to begin firing up in the next 1-2 hours.