[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 181219
SWODY1
SPC AC 181217

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0717 AM CDT SUN JUL 18 2004

VALID 181300Z - 191200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM MQT 25
WNW RHI MSP 45 NNE ATY GFK 65 NE DVL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 70 SSW P07 30 N MRF
50 NNW SVC 10 ENE SAD 20 WSW DUG ...CONT... 15 WSW YUM 20 SE EED 50
NNE LAS 40 NNE DRA 65 W DRA 60 NW NID 40 ENE SAC 25 NNE RBL 50 ESE
EKA 35 SSE OTH 30 E BLI ...CONT... 50 W ANJ 25 E VOK 10 SSE MCW 30
SE SUX 30 NW OMA 25 WSW EMP 10 SW HUT 20 W RSL 35 E REJ 30 NNW 4BQ
20 SW SHR 40 SSE CPR 50 ESE LIC LBL 30 ENE CDS 20 NE SEP 30 SSW LFK
BTR 30 NNE MOB 30 WSW TOI 25 ENE ANB 25 NNW CHA 40 E MDH 15 NNW DEC
35 W BEH 40 SE OSC.

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTN/EVE ACROSS PARTS OF
THE NORTH CENTRAL STATES....

IN RESPONSE TO DIGGING UPSTREAM JET STREAK ACROSS THE NORTHEAST
PACIFIC...CLOSED LOW OFF THE NORTHERN PACIFIC COAST WILL CONTINUE
LIFTING NORTHWARD TOWARD THE VANCOUVER ISLAND/PACIFIC NORTHWEST
COAST. EASTWARD PROGRESSION WILL BE SLOWED BY UPPER RIDGE...WHICH
MODELS SUGGEST WILL GENERALLY REMAIN STRONG THROUGH THIS PERIOD 
ACROSS THE INTERMOUNTAIN WEST/ROCKIES. HOWEVER...MODELS DO INDICATE
ANOTHER SHORT WAVE TROUGH...EMBEDDED WITHIN TROPICAL MOIST PLUME
EMANATING FROM THE LOWER LATITUDE PACIFIC... WILL PROGRESS AROUND
CREST OF RIDGE...ACROSS THE NORTHERN INTERMOUNTAIN REGION AND
NORTHERN ROCKIES.

YET ANOTHER SHORT WAVE TROUGH/JET STREAK IS TOPPING RIDGE IN BELT OF
STRONGER FLOW FROM THE CANADIAN ROCKIES INTO SOUTHERN PERIPHERY OF
EASTERN CANADIAN POLAR VORTEX. THIS FEATURE IS PROGGED TO CONTINUE
ACROSS THE CENTRAL CANADIAN PROVINCES INTO ONTARIO BY LATE TONIGHT. 


SOUTH OF THE BORDER...DOWNSTREAM OF RIDGE...BROAD UPPER TROUGHING
WILL PERSIST FROM THE MISSISSIPPI VALLEY INTO ATLANTIC COASTAL
AREAS. ONE EMBEDDED SHORT WAVE WILL CONTINUE LIFTING AROUND
EASTERN/NORTHEASTERN PERIPHERY OF UPPER OHIO VALLEY MID-LEVEL
CIRCULATION CENTER...FROM THE MID ATLANTIC COAST INTO THE LOWER
GREAT LAKES AND NEW ENGLAND.  ANOTHER WILL PROGRESS TO THE SOUTH OF
CIRCULATION... ACROSS THE SOUTHERN APPALACHIANS INTO SOUTHERN MID
ATLANTIC COASTAL AREAS.

...NORTH CENTRAL STATES...
IN STRONG LOW-LEVEL WARM ADVECTION REGIME ASSOCIATED WITH SHORT WAVE
PROGRESSING INTO CENTRAL CANADA...WEAKENING CLUSTER OF CONVECTION IS
NOW SPREADING ACROSS SOUTHERN MANITOBA INTO EXTREME NORTHERN NORTH
DAKOTA.  FURTHER WEAKENING OF THIS ACTIVITY IS EXPECTED THROUGH THE
MORNING...AND AS STRONGER LOW-LEVEL CONVERGENCE AND MID/UPPER
FORCING SHIFT ACROSS THE REMAINDER OF SOUTHERN MANITOBA INTO
ONTARIO...PRIMARY CONVECTIVE REDEVELOPMENT MAY REMAIN NORTH OF THE
MINNESOTA BORDER THIS AFTERNOON.

HOWEVER...LOW/MID-LEVEL WARM ADVECTION REGIME WILL PERSIST FROM THE
EASTERN NORTH/SOUTH DAKOTA BORDER THROUGH NORTHERN MINNESOTA ...ON
NORTHEASTERN PERIPHERY OF WESTERN U.S. RIDGE.  THIS MAY CAP
POTENTIALLY UNSTABLE BOUNDARY LAYER WITH DEW POINTS AROUND 60 ACROSS
THE DAKOTAS.  INHIBITION WILL REMAIN WEAKER ACROSS MINNESOTA...AND
LOW-LEVEL CONFLUENT BAND/THERMAL RIDGE AXIS NEAR THE NORTHERN
MINNESOTA BORDER MAY BECOME FOCUS FOR CONVECTIVE DEVELOPMENT
NEAR/SHORTLY AFTER PEAK HEATING LATE THIS AFTERNOON.
DIFLUENT UPPER FLOW REGIME WILL ENHANCE CONVECTION...AND VERTICAL
SHEAR PROFILES ON NOSE OF NORTHWESTERLY LOWER/MID TROPOSPHERIC JET
STREAK SHOULD BE SUFFICIENT FOR ISOLATED SUPERCELLS IN ENVIRONMENT
WITH MEAN MIXED LAYER CAPE OF 1000 TO 2000 J/KG.

MODELS SUGGEST STRENGTHENING WARM ADVECTION REGIME SOUTHEASTWARD
INTO THE WESTERN LAKE SUPERIOR AREA THIS EVENING...AND POTENTIAL
EXISTS FOR CONSOLIDATION OF CONVECTION AND SUBSEQUENT EVOLUTION OF
MORE ORGANIZED CONVECTIVE CLUSTER.  COOLER LOWER-LEVELS IN CLOSER
PROXIMITY TO THE UPPER GREAT LAKES/UPPER MISSISSIPPI VALLEY REGION
LIKELY WILL PRECLUDE SIGNIFICANT DESTABILIZATION AND SEVERE THREAT
BEYOND THE LATE EVENING HOURS.

,,,SOUTHERN MID ATLANTIC COAST STATES...
SUBSIDENCE IN WAKE OF SHORT WAVE TROUGH LIFTING OUT OF THE MID
ATLANTIC COASTAL AREAS IS EXPECTED TO PRECLUDE CONVECTIVE
DEVELOPMENT EAST OF THE CENTRAL/SOUTHERN APPALACHIANS WELL INTO THE
AFTERNOON HOURS.  HOWEVER...STRONG HEATING OF MOIST AIR MASS NEAR
LEE SURFACE TROUGH ACROSS THE CENTRAL CAROLINAS/SOUTHEAST VIRGINIA
WILL CONTRIBUTE TO MODERATELY STRONG POTENTIAL INSTABILITY...WITH
MEAN MIXED LAYER CAPE BY LATE AFTERNOON LIKELY APPROACHING 2000
J/KG.

MAGNITUDE OF CAPE...AND CONVECTIVE INSTABILITY...WILL BE LIMITED BY
RELATIVELY WARM MID-LEVEL ENVIRONMENT WITH WEAK LAPSE RATES. 
LOW-LEVEL FLOW REGIME WILL ALSO BE QUITE WEAK...BUT 30 TO 40 KT
SOUTHWESTERLY MID-LEVEL FLOW AHEAD OF APPROACHING TROUGH AXIS WILL
ENHANCE STORM MOTION...AND POTENTIAL FOR MID-LEVEL UPDRAFT
ROTATION...AS CONVECTION DEVELOPS WITH INCREASING LARGE-SCALE
FORCING BY EARLY EVENING.  SHEAR MAY ENHANCE POTENTIAL FOR
MARGINALLY SEVERE HAIL...BUT SOMEWHAT BETTER POTENTIAL FOR STRONG
GUSTY WINDS WILL EXIST IN STRONGER CELLS...BEFORE ACTIVITY WEAKENS
AS BOUNDARY LAYER STABILIZES WITH LOSS OF HEATING.

...NORTHERN INTERMOUNTAIN REGION/ROCKIES...
FORCING ASSOCIATED WITH WAVE EMBEDDED WITHIN TROPICAL MOIST PLUME
MAY SUPPORT DEVELOPMENT OF NUMEROUS THUNDERSTORMS ACROSS THE
NORTHERN ROCKIES TODAY.  RISK OF HAIL WILL ACCOMPANY THIS
ACTIVITY...MAINLY AT HIGHER ELEVATIONS.  

ALTHOUGH LOWER LEVELS APPEAR LIKELY TO REMAIN RATHER DRY IN THE LEE
OF THE MONTANA ROCKIES...VERY DEEP MIXED BOUNDARY LAYER WILL BE
SUPPORTIVE OF MICROBURSTS...AS HIGH-BASED CONVECTION DEVELOPS WITH
STRONGER FORCING OFF THE HIGHER TERRAIN TOWARD EARLY EVENING. 
STRENGTHENING EASTERLY LOW-LEVEL JET ACROSS SOUTHEAST/EAST CENTRAL
MONTANA...BENEATH WEAK WESTERLY MID/UPPER FLOW...WILL CONTRIBUTE TO
INCREASINGLY FAVORABLE SHEAR FOR SMALL ORGANIZED CLUSTER WITH
SOMEWHAT BROADER SCALE DAMAGING WIND POTENTIAL THIS EVENING.  THREAT
MAY BE SHORT-LIVED THOUGH...DUE TO RELATIVELY RAPID
COOLING/STABILIZATION OF BOUNDARY LAYER AFTER SUNSET.

IN WAKE OF LEAD SHORT WAVE...STRONG HEATING AND DEVELOPMENT OF DEEP
MIXED BOUNDARY LAYER IS EXPECTED IN THE LEE OF THE CASCADES.  THIS
WILL PROVIDE FAVORABLE ENVIRONMENT FOR MICROBURSTS AS WIDELY
SCATTERED CONVECTION DEVELOPS IN PEAK AFTERNOON HEATING.  DOWNWARD
TRANSFER OF MOMENTUM ASSOCIATED WITH MODERATELY STRONG SOUTHERLY
JET...EAST OF UPPER TROUGH APPROACHING THE PACIFIC COAST...MAY FAVOR
STRONGER DOWNBURSTS...BUT OVERALL DAMAGING WIND THREAT IS EXPECTED
TO REMAIN FAIRLY ISOLATED.

..KERR/CROSBIE.. 07/18/2004

...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.