[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 121233
SWODY1
SPC AC 121231

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0731 AM CDT SAT JUN 12 2004

VALID 121300Z - 131200Z

THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM OLU 10
ESE OMA LWD 40 SW IRK 10 E SZL JLN TUL PNC 10 SE ICT 10 SSE RSL HLC
EAR OLU.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 75 S
MRF 25 E MAF 40 WSW CSM P28 30 W HLC MCK 25 ESE MHN 15 E MHE 30 NW
MKT 35 WSW DLH RHI MKE 10 SE SBN 30 NE DAY CMH UNI 35 SW HTS 45 SW
SDF 10 SSW OWB CGI HRO FSM 10 ENE DUA FTW 20 SSE DRT.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM DAB 30
SW JAX 55 N AYS 30 E ATL 45 ESE AND 20 S CAE 10 SSW CHS.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 SW MRF 40 NNW BGS
25 S GAG 40 W P28 45 ESE LIC 45 S 4FC 30 WSW GJT 45 WSW PUC 20 SSW
SLC 35 ESE LND 45 ENE COD 45 W GTF 85 NW FCA ...CONT... 55 NE HVR 30
W ISN MOT 80 NE DVL ...CONT... 10 WNW ERI 25 ESE EKN 30 S ROA 25 SW
GSO 30 S SOP 35 SW ILM ...CONT... 20 SSW HUM 15 NE LFT 30 E POE 40
SSW SHV 40 SW TYR 20 WSW ACT 45 SE DRT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 NE BLI 20 SE SEA
35 SSE OLM AST.

...THERE IS A MDT RISK OF SVR TSTMS TODAY ACROSS PARTS OF THE
CENTRAL PLAINS...INCLUDING MUCH OF CNTRL/ERN KS INTO WRN MO....

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SURROUNDING AREAS OF THE
CNTRL/SRN PLAINS...MID/UPR MS VLY...AND LWR OH VLY ....

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SOUTH
ATLANTIC COAST STATES....

DOWNSTREAM OF VERY STRONG ZONAL UPPER JET NOSING TOWARD THE PACIFIC
NORTHWEST COAST...GRADUAL EASTWARD PROGRESSION OF LARGE-SCALE TROUGH
OUT OF THE INTERMOUNTAIN WEST/ROCKIES/PLAINS WILL CONTINUE DURING
THIS FORECAST PERIOD.  SIGNIFICANT SHORT WAVE EMBEDDED WITHIN
BROADER CYCLONIC FLOW REGIME HAS ALREADY LIFTED ACROSS MUCH OF THE
NORTH CENTRAL STATES AND WILL CONTINUE INTO THE CENTRAL CANADIAN
PROVINCES EARLY TODAY. HOWEVER...WEAKER UPSTREAM IMPULSE IS EVIDENT
IN WATER VAPOR IMAGERY PROGRESSING EASTWARD OUT OF THE CENTRAL
ROCKIES...WITH ANOTHER SHORT WAVE AMPLIFYING A BIT FARTHER
UPSTREAM...ACROSS THE GREAT BASIN.  FARTHER SOUTH...JET STREAK
EMBEDDED WITHIN WEAK SUBTROPICAL BRANCH OF THE WESTERLIES IS EVIDENT
NEAR THE ARIZONA/SONORA BORDER.

AS THESE FEATURES PROGRESS EASTWARD TODAY...ASSOCIATED FORCING FOR
UPWARD VERTICAL MOTION WILL SUPPORT FAIRLY WIDESPREAD AND STRONG
CONVECTIVE DEVELOPMENT ACROSS MUCH OF THE CENTRAL STATES.  VERY
MOIST BOUNDARY LAYER IS IN PLACE...WITH DEW POINTS AT OR ABOVE 70F
OVER BROAD AREA...SOUTH/WEST OF FRONTAL ZONE EXTENDING FROM THE MID
ATLANTIC COAST INTO THE UPPER MISSISSIPPI VALLEY...AND EAST OF
INITIAL WEAK FRONT/DRY LINE EXTENDING FROM THE UPPER MISSISSIPPI
VALLEY INTO THE SOUTHERN HIGH PLAINS.

...CENTRAL PLAINS/MID AND LOWER MISSOURI VALLEY...
WHILE MODELS ARE SIMILAR WITH REGARD TO THE LARGE-SCALE FEATURES...
CONSIDERABLE VARIABILITY EXISTS CONCERNING THE DETAILS OF CONVECTIVE
DEVELOPMENT TODAY.  BOTH THE ETA AND GFS SUGGEST STRONGLY DIVERGENT
UPPER FLOW FIELD--IN WAKE OF VIGOROUS LEAD SHORT WAVE...AND AHEAD OF
CENTRAL/SOUTHERN GREAT BASIN SHORT WAVES--WILL PROGRESS EASTWARD
INTO THE CENTRAL PLAINS DURING THE LATE AFTERNOON HOURS.  THIS WILL
BE NEAR/SHORTLY AFTER PEAK HEATING...WHEN FORECAST SOUNDINGS
INDICATE STRONG CONVECTIVE INSTABILITY AND VERY LARGE CAPE...WITH
100 MB MEAN MIXED VALUES UP TO 4000 J/KG.

MORE UNCERTAIN IS THE EXTENT OF CONVECTIVE DEVELOPMENT WHICH WILL BE
ONGOING BY THIS TIME...AND THIS APPEARS STRONGLY TIED TO WEAKER
IMPULSE CURRENTLY MIGRATING OUT OF WYOMING/COLORADO.  ETA MODEL FOR
SEVERAL RUNS HAS BEEN CONSISTENT IN SUGGESTING FAIRLY RAPID
EVOLUTION OF A CONVECTIVE CLUSTER IN THE VICINITY OF THE KANSAS/
NEBRASKA BORDER BY THE 15-18Z TIME FRAME.  OBSERVATIONAL DATA
SUPPORTS THIS SCENARIO...AND CONVECTIVE INITIATION IS EXPECTED IN
RESPONSE TO STRONG LOWER/MID TROPOSPHERIC WARM ADVECTION.  GIVEN
MAGNITUDE OF INSTABILITY ABOVE NEAR SURFACE/CAPPING INVERSION
LAYER...VERY LARGE HAIL IS POSSIBLE IN STRONGEST CELLS.

AS CONVECTIVE CLUSTER EVOLVES...MODERATE WEST SOUTHWESTERLY
MID/UPPER FLOW WILL SUPPORT PROPAGATION INTO SOUTHWEST IOWA/
NORTHWEST MISSOURI/NORTHEAST KANSAS BY EARLY AFTERNOON.  STRONGER
SURFACE HEATING AND MORE RAPID DISSIPATION OF CURRENT NORTHERN/
CENTRAL MISSOURI COLD POOL MAY SUPPORT INCREASING POTENTIAL FOR
DAMAGING WINDS ALONG GUST FRONT ASSOCIATED WITH NEW COLD POOL. 
ACTIVITY MAY PERSIST THROUGH THE LATE AFTERNOON AND EVENING
HOURS...PROGRESSING EAST OF THE MISSISSIPPI RIVER THROUGH CENTRAL
ILLINOIS...POSSIBLY INDIANA BEFORE WEAKENING/DIMINISHING.

MEANWHILE...ALONG REINFORCED OUTFLOW BOUNDARY FROM THE MISSOURI
OZARKS INTO VICINITY OF SURFACE LOW ACROSS NORTH CENTRAL
KANSAS...ENHANCED LOW-LEVEL CONVERGENCE/WARM ADVECTION IS EXPECTED
TO SUPPORT MOST INTENSE CONVECTIVE ACTIVITY THIS FORECAST PERIOD. 
CAP SHOULD WEAKEN AS UPPER FORCING INCREASES IN THE 21-00Z TIME
FRAME. THOUGH WIND FIELDS/SHEAR PROFILES IN GENERAL WILL ONLY BE
MODERATE IN STRENGTH...SOUTHEASTERLY SURFACE FLOW  ACROSS
CENTRAL/EASTERN KANSAS WILL ENHANCE LOW-LEVEL HODOGRAPHS.  IN
CONJUNCTION WITH STRONG INSTABILITY...THIS SHOULD BE SUFFICIENT FOR
A FEW TORNADIC SUPERCELLS...WITH POTENTIAL FOR AN ISOLATED STRONG
TORNADO OR TWO.

ACTIVITY LIKELY WILL MERGE INTO ANOTHER SMALL MESOSCALE CONVECTIVE
SYSTEM DURING THE EVENING HOURS.  THIS SHOULD BE ACCOMPANIED BY
GREATER POTENTIAL FOR DAMAGING WIND GUSTS AS IT PROPAGATES EASTWARD
ALONG RETREATING OUTFLOW BOUNDARY...ON NOSE OF STRENGTHENING
LOW-LEVEL JET...THROUGH THE LOWER MISSOURI VALLEY.

...SOUTHERN HIGH PLAINS...
LATE AFTERNOON CONVECTION ALONG DRY LINE SHOULD BE MORE EXTENSIVE
TODAY. DEVELOPMENT WILL BE AIDED BY SUBTROPICAL JET STREAK...
PROGGED TO NOSE ACROSS SOUTHWEST TEXAS BY LATE AFTERNOON.  A FEW
SUPERCELLS ARE LIKELY WITH LARGE HAIL/DAMAGING WIND GUSTS...AND A
FEW TORNADOES.

...NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY...
CONSIDERABLE UNCERTAINTY ABOUT CONVECTIVE THREAT EXISTS ACROSS THIS
AREA...FROM NORTHEAST NEBRASKA/SOUTHEAST SOUTH DAKOTA ACROSS
NORTHERN IOWA/SOUTHERN MINNESOTA INTO WISCONSIN...PARTICULARLY IF
CONVECTION EVOLVES AS EXPECTED FARTHER SOUTH.  HOWEVER...BOUNDARY
LAYER IN WAKE OF INITIAL WEAK SURFACE FRONT WILL REMAIN MOIST ENOUGH
FOR SUBSTANTIAL DESTABILIZATION WITH SURFACE HEATING.  SCATTERED
THUNDERSTORM ACTIVITY APPEARS POSSIBLE BENEATH CYCLONIC MID/UPPER
FLOW REGIME DURING THE AFTERNOON HOURS...WITH RISK OF HAIL/GUSTY
WINDS IN STRONGEST CELLS.

...SOUTH ATLANTIC COAST STATES...
SURFACE FRONT ADVANCING SOUTHWARD TO THE LEE OF THE SOUTHERN
APPALACHIANS WILL PROVIDE A FOCUS FOR THUNDERSTORMS TODAY.  THIS
WILL OCCUR IN WEAK FLOW/WEAK SHEAR REGIME BENEATH MID/UPPER RIDGE. 
HOWEVER...STRONG HEATING OF BOUNDARY LAYER WITH LOWER 70S DEW POINTS
MAY CONTRIBUTE TO SUFFICIENT DESTABILIZATION FOR VIGOROUS UPDRAFTS
WITH LOCALLY VERY HEAVY DOWNPOURS...ACCOMPANIED BY ISOLATED
DOWNBURSTS.

..KERR/CROSBIE.. 06/12/2004

...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.