[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 180621
SWODY1
SPC AC 180618

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0118 AM CDT TUE MAY 18 2004

VALID 181200Z - 191200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 10 S
HUL 15 WSW PVD 20 WSW DOV 45 ESE PKB 10 SW EVV HRO 20 W GAG 10 WSW
EHA 15 WNW LAA 10 NW DEN CPR 15 NE COD 35 NNE BIL 25 SSE GGW 45 ENE
ISN DVL 45 S JMS 30 NNE 9V9 OFK 10 WSW LWD 15 S MMO 15 SE DTW.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 N MLB 25 WNW FMY
...CONT... 45 WNW MFE 40 NW ALI 30 SSE AUS 50 ENE ACT 30 SW PRX 35 S
MLC 45 E OKC 35 NE CSM 20 NW AMA 35 NE TCC 30 S RTN 50 E GUC 35 SW
MTJ 30 W 4BL 40 SSW BCE 65 NNE P38 30 N ELY 15 SSW EKO 30 WSW BAM 50
NW TVL 15 E UKI EKA ...CONT... 30 W RRT 25 E FAR 25 E OTG 10 S ALO
15 NE DBQ 30 NNE MKE 15 S OSC.

...THERE IS A SLGT RISK OF SVR TSTMS OVER A BROAD AREA EXTENDING
FROM THE NORTHEAST SWWD ACROSS MID ATLANTIC/OH VALLEY TO THE CENTRAL
PLAINS...AND NWWD TO NRN HIGH PLAINS/DAKOTAS...

...SYNOPSIS...
UPPER RIDGE WILL CONTINUE TO STRENGTHEN OVER THE NERN PACIFIC WITH
DOWNSTREAM TROUGH ALONG THE WEST COAST DEVELOPING SWD TO OFF THE SRN
CA COAST BY 12Z WEDNESDAY.  HEIGHTS WILL RISE ACROSS THE PLAINS
STATES WHILE AN UPPER TROUGH OVER ONTARIO/UPPER GREAT LAKES MOVES
EWD TO THE NORTHEAST STATES.

AT THE SURFACE...COLD FRONT ASSOCIATED WITH NORTHEAST TROUGH WILL
MOVE EWD/SEWD ACROSS ONTARIO/QUEBEC REACHING FROM THE ST. LAWRENCE
RIVER VALLEY SWWD TO WRN NY AND CENTRAL OH BY 00Z...AND THEN OFF THE
NEW ENGLAND COAST TO OH VALLEY BY 12Z WEDNESDAY.  THIS FRONT WILL
SAG SLOWLY SWD THIS MORNING ACROSS IND TO MO...AS IT BECOMES
QUASI-STATIONARY FROM THE MID MS VALLEY TO CENTRAL PLAINS THIS
FORECAST PERIOD.  MEANWHILE...A DRY LINE WILL MIX EWD...REACHING A
LINE FROM SWRN KS TO WRN OK SWD TO THE TX BIG BEND BY LATE THIS
AFTERNOON.  A LEE TROUGH WILL DEVELOP ALONG THE NRN/CENTRAL HIGH
PLAINS AS A SHORT WAVE TROUGH TRACKS NEWD ACROSS THE NRN
INTERMOUNTAIN WEST TO ERN MT.

...NEW ENGLAND SWWD TO OH VALLEY...
30-40 KT WSWLY LLJ ASSOCIATED WITH APPROACHING GREAT LAKES UPPER
TROUGH WILL CONTINUE TO ADVECT MOISTURE NEWD ACROSS THE UPPER OH
VALLEY TO NERN STATES WITH LOWER-MID 60 SURFACE DEWPOINTS AS FAR
NEWD AS WRN NEW ENGLAND.  ALTHOUGH LAPSE RATES WILL BE WEAK...THE
LOW-LEVEL MOISTENING WILL RESULT IN SUFFICIENT DESTABILIZATION FOR
MARGINAL INSTABILITY.  ONGOING CONVECTION ACROSS PA MAY INTENSIFY
ACROSS ERN PA/NJ THIS MORNING AS THE AIR MASS ACROSS THE MID
ATLANTIC AREA DESTABILIZES WITH THE ONSET OF SURFACE HEATING. 
HOWEVER...THE GREATER SEVERE THREAT IS EXPECTED TO BE WITH STORMS
THAT DEVELOP ALONG THE COLD FRONT AS IT MOVES ACROSS WRN NEW ENGLAND
TO NY AND NRN/WRN PA BY LATE THIS AFTERNOON AND EARLY EVENING. 
40-50 KT OF WLY MID-LEVEL FLOW WILL RESULT IN SUFFICIENT DEEP LAYER
SHEAR FOR ORGANIZED STORMS WITH EMBEDDED SUPERCELLS POSSIBLE ALONG
THE FRONT.  30-45 KT OF WLY 850 MB FLOW WILL FAVOR DAMAGING WINDS
WITH HAIL A THREAT AS WELL.  SQUALL LINE IS EXPECTED TO EXTEND SWWD
ACROSS OH INTO SRN IND THIS EVENING... GIVEN SUFFICIENT INSTABILITY.
 DEEP LAYER SHEAR WILL BE WEAKER OVER THIS AREA WITH A THREAT FOR
MULTI-CELLS ALONG THE COLD FRONT.

...KS EWD MID MS VALLEY...
A SHORT WAVE TROUGH...CURRENTLY LOCATED OVER SRN UT...WILL MOVE EWD
ACROSS KS THIS MORNING AND INTO THE MID MS VALLEY THIS
AFTERNOON/EVENING TIME FRAME BEFORE IT WEAKENS IN CONFLUENT FLOW
OVER THE SRN GREAT LAKES TONIGHT.  MODELS SHOW CONVECTION WITH THIS
FEATURE ACROSS CENTRAL-ERN KS THIS MORNING.  CAPE/SHEAR VALUES
INDICATE AN ORGANIZED SEVERE THREAT AS THIS ACTIVITY
SPREADS/DEVELOPS EWD ALONG THE SURFACE FRONT INTO MO/IL.

ADDITIONAL ELEVATED STORMS MAY SPREAD EWD ACROSS NRN KS INTO NRN
MO/SRN IA LATER THIS EVENING/TONIGHT AS 40-50 KT SWLY LLJ DEVELOPS 
THIS EVENING FROM THE ERN TX PANHANDLE INTO CENTRAL KS SUPPORTING
STRONG WAA REGIME ALONG AND NORTH OF THE SURFACE FRONT. 
THUNDERSTORMS DEVELOPING OVER THE CENTRAL HIGH PLAINS WILL LIKELY
MOVE EWD ACROSS SRN NEB/NRN KS WITH THE WAA ALONG THE NOSE OF THE
LLJ SUPPORTING A SEVERE THREAT EWD WITH HAIL BEING THE PRIMARY
THREAT.

MOST OF CENTRAL/WRN KS INTO NWRN OK IS EXPECTED TO REMAIN CAPPED
TODAY PREVENTING THE DEVELOPMENT OF SURFACE BASED CONVECTION ALONG
THE SURFACE FRONT AND DRY LINE.  HOWEVER...IF LOW-LEVEL CONVERGENCE
ALONG THESE BOUNDARIES CAN BECOME SUFFICIENT TO WEAKEN THE CAP...A
VERY UNSTABLE AIR MASS WITH STRONG DEEP LAYER SHEAR WOULD SUPPORT A
FEW DISCRETE SUPERCELLS WITH LARGE HAIL AND ISOLATED TORNADOES. 
PORTIONS OF CENTRAL KS AND FAR NRN OK WILL NEED TO BE MONITORED IN
LATER OUTLOOKS FOR A POTENTIAL UPGRADE IN PROBABILITIES AND/OR
CATEGORICAL RISK...IF CONVECTION BECOMES MORE LIKELY.

...CENTRAL/NRN HIGH PLAINS EWD TO DAKOTAS/NEB...
SELY UPSLOPE FLOW INTO THE CENTRAL/NRN HIGH PLAINS IS EXPECTED IN
RESPONSE TO THE APPROACH OF THE UPSTREAM SHORT WAVE TROUGH. 
MOISTURE ADVECTION WITHIN THIS SELY FLOW WILL RESULT IN LOWER 50
SURFACE DEWPOINTS RETURNING TO THE HIGH PLAINS OF CENTRAL/ERN MT BY
00Z AND AROUND 60 INTO ERN WY. SURFACE HEATING COMBINED WITH THE
LOW-LEVEL MOISTURE AND STEEP LAPSE RATES WILL RESULT IN MODERATE
INSTABILITY ACROSS NERN CO AND MARGINAL INSTABILITY NWD TO ERN
WY/SERN MT FOR THUNDERSTORMS TO DEVELOP ALONG THE HIGHER TERRAIN
THIS AFTERNOON.  THIS INSTABILITY COMBINED WITH STRONG DEEP LAYER
SHEAR WILL SUPPORT ORGANIZED SEVERE STORMS.  THIS ACTIVITY WILL
LIKELY EVOLVE INTO ONE OR MORE MCS/S ACROSS THE DAKOTAS THIS EVENING
AND OVERNIGHT AS LARGE SCALE ASCENT ACROSS THE NRN PLAINS INCREASES
WITH THE APPROACH OF THE UPSTREAM TROUGH AND SLY LLJ INCREASES TO 50
KT SUPPORTING A WAA REGIME OVER THIS AREA.

...LOWER MS VALLEY/GULF COAST STATES TO TN VALLEY...
MARGINAL LAPSE RATES COMBINED WITH A MOIST AIR MASS WILL AGAIN
RESULT IN MARGINAL INSTABILITY FOR THUNDERSTORMS.  WEAK DEEP LAYER
SHEAR SUGGESTS THESE STORMS WILL BE SLOW MOVING PULSE-TYPE WITH THE
GREATEST THREAT BEING ISOLATED WET-MICROBURSTS AND LOCALIZED HEAVY
RAIN.

..PETERS/TAYLOR.. 05/18/2004

...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.