[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 080556
SWODY1
SPC AC 080552

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1252 AM CDT SAT MAY 08 2004

VALID 081200Z - 091200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 WSW
BUF ELM IPT 25 NNW CXY HLG CAK MMO DSM BIE CNK EAR ANW VTN 10 NW 4BQ
DIK 10 NE BIS 20 ESE JMS AXN RWF RST MKG MTC.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 NE JAX 10 WSW CTY
...CONT... 20 SSW CEW AUO 50 SSW TYS 10 NW 5I3 20 SW UNI 10 SW DAY
15 WNW SPI STJ 35 WNW EMP 20 ESE GAG 30 NE BGS 25 N SJT DUA TXK 15
SE BPT ...CONT... 50 W MRF CNM TCC 10 E SNY 55 NNE DGW 15 ENE COD
SUN 10 ESE 4LW MFR 15 WNW ONP ...CONT... MSS 15 SE BOS ...CONT... 20
ENE ACY 10 N BWI 40 NNW RIC 15 S RIC 10 SE ECG.

...THERE IS A SLGT RISK OF SVR TSTMS TODAY/TONIGHT FROM PARTS OF THE
NORTHERN PLAINS/MID MISSOURI VALLEY EASTWARD INTO THE LOWER GREAT
LAKES REGION....

MODELS INDICATE BLOCKING PATTERN WILL PERSIST ACROSS THE NORTHEAST
PACIFIC THROUGH THIS FORECAST PERIOD...WITH MERGING BELTS OF
STRONGER FLOW EAST OF BLOCK CONTINUING TO STRADDLE THE CANADIAN/U.S.
BORDER.  NORTHERN BRANCH...GENERALLY NORTH OF THE U.S. BORDER
...STILL APPEARS TO BE MOST PROMINENT...WITH STRONGEST EMBEDDED JET
STREAK PROGGED TO SHIFT EAST OF THE CANADIAN MARITIMES.  HOWEVER...
UPSTREAM...MODELS SUGGEST ANOTHER SIGNIFICANT SHORT WAVE/JET STREAK
WILL DIG SOUTHWARD ACROSS THE CANADIAN ROCKIES.  AS THIS OCCURS...A
STRONG JET STREAK...EMANATING FROM SOUTHERN STREAM CLOSED LOW/TROUGH
OFF THE PACIFIC NORTHWEST COAST...IS PROGGED TO SHIFT ACROSS THE
NORTHERN INTERMOUNTAIN REGION/ROCKIES INTO THE NORTHERN PLAINS BY
EARLY SUNDAY.

...MID MISSOURI/UPPER MISSISSIPPI VALLEY...
AGEOSTROPHIC FORCING IN RIGHT ENTRANCE REGION OF UPPER GREAT LAKES/
ST. LAWRENCE VALLEY UPPER JET STREAK STILL APPEARS LIKELY TO SUPPORT
EXTENSIVE CONVECTIVE DEVELOPMENT NORTH OF WARM FRONT...FROM THE MID
MISSOURI VALLEY INTO THE LOWER LAKES...THROUGH DAYBREAK.  THIS WILL
SLOW NORTHWARD RETREAT OF SURFACE WARM FRONT...WITH BOUNDARY LIKELY
BECOMING QUASI-STATIONARY FROM NORTH CENTRAL IOWA INTO NORTHEAST
NEBRASKA.

MID-LEVEL WARMING ON WEST SOUTHWESTERLY FLOW WILL STRENGTHEN CAP
ONCE AGAIN ALONG FRONT THROUGH THE MID MISSOURI VALLEY EARLY IN THE
DAY.  HOWEVER...SOUTHERLY LOW-LEVEL JET IS PROGGED TO CONTINUE TO
IMPINGE ON FRONT NEAR THE IOWA/NEBRASKA BORDER..AND...BY LATE
AFTERNOON...ANOTHER WEAK SHORT WAVE IS PROGGED TO MIGRATE OUT OF THE
CENTRAL ROCKIES.  MODELS SUGGEST THIS WILL WEAKEN INHIBITION
SUFFICIENTLY FOR CONVECTIVE INITIATION.  ACTIVITY LIKELY WILL
RAPIDLY BECOME SEVERE IN ENVIRONMENT WITH STEEP LAPSE RATES AND
LARGE CAPE OF 2000 TO 3000 J/KG.  SHEAR PROFILES LIKELY WILL BE
SUFFICIENT FOR AT LEAST MID-LEVEL UPDRAFT ROTATION...WHICH WILL
ENHANCE POTENTIAL FOR ISOLATED VERY LARGE HAIL.

RISK OF LARGE HAIL/DAMAGING WINDS WILL PERSIST ACROSS EASTERN
NEBRASKA/IOWA THROUGH THE EVENING HOURS...WITH FORCING ON NOSE OF
STRENGTHENING LOW-LEVEL JET CONTRIBUTING TO EVOLUTION OF LARGE
CONVECTIVE CLUSTER.  OVERNIGHT...LARGE HAIL POTENTIAL SHOULD
DECREASE AS HEAVY RAIN BECOMES AN INCREASING THREAT IN SLOW
MOVING/TRAINING CONVECTION.

...LOWER GREAT LAKES/UPPER OHIO VALLEY...
FORCING IN RIGHT ENTRANCE REGION OF UPPER JET...AND ASSOCIATED AREA
OF ENHANCED LOW-LEVEL WARM ADVECTION...WILL SPREAD EASTWARD INTO
LAKE ERIE AND ADJACENT AREAS OF NEW YORK/PENNSYLVANIA/AND OHIO BY
LATE AFTERNOON.  IN WAKE OF SURFACE RIDGE SHIFTING EAST OF THE
APPALACHIANS...SURFACE WARM FRONT WILL REDEVELOP ACROSS THIS
REGION...AND SHOULD BECOME FOCUS FOR CONVECTIVE DEVELOPMENT THIS
AFTERNOON AND EVENING. WITH MEAN MIXED LAYER CAPE PROGGED TO
INCREASE TO 1000 TO 2000 J/KG...STRONG VERTICAL SHEAR PROFILES WILL
BE SUFFICIENT FOR SUPERCELLS.  LARGE HAIL APPEARS LIKELY... WITH
POTENTIAL FOR DAMAGING WIND GUSTS...PERHAPS ISOLATED TORNADOES NEAR
IMMEDIATE VICINITY OF SURFACE WARM FRONT.

...NORTHERN PLAINS...
ALTHOUGH LOW-LEVEL MOISTURE WILL BE SPARSE NEAR LEE SURFACE LOW
ACROSS SOUTHEAST MONTANA...LAPSE RATES ON NOSE OF LOW-LEVEL THERMAL
RIDGE WILL CONTRIBUTE TO SUFFICIENT INSTABILITY FOR VIGOROUS
CONVECTIVE DEVELOPMENT BY LATE THIS  AFTERNOON.  ACTIVITY WILL BE
ENHANCED BY FORCING ASSOCIATED WITH SOUTHERN STREAM JET STREAK. 
EVOLUTION OF GROWING CLUSTER OF STORMS APPEARS POSSIBLE BY EARLY
EVENING ACROSS EASTERN MONTANA AND THE WESTERN DAKOTAS... WHERE DEEP
MIXED BOUNDARY LAYER WILL PROVIDE FAVORABLE ENVIRONMENT FOR
STRONG/DAMAGING WIND GUSTS.  OVERNIGHT...STRONG WIND POTENTIAL WILL
DIMINISH AS CONVECTION BECOMES INCREASING BASED ABOVE COOLER
BOUNDARY LAYER OVER THE EASTERN DAKOTAS.

...CENTRAL APPALACHIANS/NORTH CAROLINA...
UPPER FORCING WILL BE MINIMAL...BUT HIGHER TERRAIN AND SURFACE FRONT
NOSING SOUTHWARD IN THE LEE OF THE APPALACHIANS MAY PROVIDE FOCUS
FOR AT LEAST WIDELY SCATTERED AFTERNOON/EVENING THUNDERSTORMS.

..KERR.. 05/08/2004

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.