[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 191237
SWODY1
SPC AC 191236

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0736 AM CDT TUE APR 19 2005

VALID 191300Z - 201200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 10 NE
HLC 20 NW LIC 15 SE DEN 20 SSW FCL 20 NW CYS 15 N AIA 15 WNW ANW 20
NW SUX 35 WSW MCW 20 NE LSE 40 SSE CWA 25 S MTW 40 SSE MKE 35 NW MMO
20 WNW BRL P35 10 NE HLC.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25 SE
P07 60 S CDS 40 SE CDS 30 S LTS SPS 35 NNW MWL 25 SSE DRT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 WSW BUF ELM AVP 25
SSE NEL ...CONT... 15 S ILM SPA 65 WSW LOZ 30 SE SDF 30 NNW LUK 20
ESE MIE 10 E CMI 35 SSW UIN 40 N JLN 35 ENE MLC 30 SE TYR 15 E LFK
30 SSE POE 30 NE MSY 25 S GPT ...CONT... 35 SW P07 20 NNE BGS 35 W
CDS 10 SSW LBL 45 E LAA 40 SSE LIC 50 WNW COS 20 WNW MTJ 50 SSW BCE
35 ENE DRA 25 NE MER 50 SE RBL 15 N SVE 45 WSW MQM 20 NNE WEY 40 WNW
GDV 35 SE ISN 45 ESE MOT DVL 70 W RRT.

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL HI PLNS TO THE
MID MS VLY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF WRN AND NW TX...

...SYNOPSIS...
NRN NV CLOSED LOW EXPECTED TO EDGE ONLY SLOWLY E THIS PERIOD AS
RIDGE BUILDING TO ITS N /WELL DEPICTED IN WV IMAGERY/ TEMPORARILY
RESULTS IN DEVELOPMENT OF A REX BLOCK. A SPEED MAX NOW IN THE SWRN
SECTOR OF THE LOW SHOULD REDEVELOP NE INTO ERN FLANK OF SYSTEM BY
12Z WEDNESDAY AS ADDITIONAL MAXIMA DROP S/SE INTO THE SRN GRT BASIN.

FARTHER S...SATELLITE DATA SUGGEST THAT SRN BRANCH JET HAS BECOME
LESS WELL DEFINED AND ORIENTED MORE SW/NE RELATIVE TO PREVIOUS
DAYS...POSSIBLY IN RESPONSE TO ENCROACHMENT OF GRT BASIN LOW. 
NEVERTHELESS...SOME SEMBLANCE OF A SRN BRANCH DOES PERSIST...AND A
POSSIBLE IMPULSE IN THIS FLOW IS APPARENT ATTM OVER SW TX.

ELSEWHERE...VORT WHICH MOVED ACROSS THE SRN RCKYS AND CNTRL PLNS
DURING THE PAST 48 HRS SHOULD SLOWLY WEAKEN AS IT TURNS MORE EWD IN
CONFLUENT WLY FLOW OVER THE UPR MIDWEST.

AT LWR LEVELS...ERN PORTION OF NRN PLNS COLD FRONT SHOULD CONTINUE
SLOWLY SE ACROSS THE UPR GRT LKS/UPR MS VLY LATER TODAY/ TONIGHT...
WHILE WRN PART NOSES S AT A FASTER RATE INTO ERN WY/WRN SD/NW NEB. 
ATTM...SURFACE ANALYSES DEPICT A DOUBLE STRUCTURE TO THE FRONT IN
NEB/WY...WITH A PREFRONTAL WIND SHIFT LINE EXTENDING FROM NEAR OFK
TO NEAR OGA TO NEAR CYS.

...CNTRL HI PLNS TO LWR MO VLY...
A CONCENTRATED AREA OF THUNDERSTORMS WILL LIKELY FORM THIS AFTERNOON
AND PERSIST THROUGH TONIGHT ALONG AND BEHIND COLD FRONT CROSSING
WY/SD AND NEB. THE FIRST SURFACE-BASED STORMS WILL PROBABLY DEVELOP
DURING THE MID AFTERNOON INVOF PREFRONTAL TROUGH OVER WRN NEB/SE
WY...WHERE COMBINATION OF DIURNAL HEATING... INCREASINGLY MOIST
UPSLOPE FLOW AND UPR DIFFLUENCE WILL LEAD TO THE GREATEST
DESTABILIZATION.  A BIT LATER IN THE DAY...ACTIVITY SHOULD ALSO
DEVELOP EWD ALONG FRONT INTO ERN NEB AND IA...AND SWD INTO NE CO.

THE MID/UPR FLOW WILL REMAIN MODEST OVER THE REGION...WITH THE 500
MB FLOW RANGING FROM SSWLY AT 30 KTS IN NE CO/SE WY TO WSWLY AT 25
KTS IN ERN NEB.  BUT THE RESULTING DEEP SHEAR SHOULD BE SUFFICIENT
FOR SUSTAINED STORMS/SUPERCELLS...ESPECIALLY IN SRN/WRN NEB WHERE
FAIRLY CLOUD-FREE SKIES AHEAD OF THE STORMS AND STEEP MID LEVEL
LAPSE RATES COULD BOOST SBCAPE TO 2500 J/KG.  THIS WILL PROMOTE A
THREAT FOR BOTH LARGE HAIL AND DAMAGING WIND THROUGH EARLY TONIGHT. 
FARTHER E...SOMEWHAT GREATER MOISTURE AVAILABILITY AND SLIGHTLY
STRONGER WIND FIELD IN WAKE OF IA UPPER VORT MAY COMPENSATE FOR MORE
ABUNDANT CLOUDINESS TO SUPPORT A LOCALLY ENHANCED WIND/HAIL THREAT
IN IA.

THE RELATIVELY HIGH LCLS AND MODEST WIND FIELDS SHOULD MITIGATE
OVERALL TORNADO THREAT.  BUT GIVEN THE DEGREE OF INSTABILITY AND THE
LIKELIHOOD FOR BACKED FLOW INVOF PREFRONTAL TROUGH...A TORNADO OR
TWO COULD OCCUR IN SRN NEB...AND PERHAPS IN IA.

THE STORMS WILL LIKELY CONSOLIDATE INTO A SOLID BAND THAT DRIFTS
SLOWLY S/SE ACROSS SRN NEB/IA AND PERHAPS INTO NE KS/NW MO TONIGHT. 
BUT WITH SHORT WAVE RIDGING EXPECTED TO OVERSPREAD THE REGION THIS
EVENING AS GRT BASIN LOW EDGES EWD...THE STORMS SHOULD WEAKEN BY
MIDNIGHT.  ADDITIONAL /ELEVATED/ ACTIVITY MAY ALSO DEVELOP LATE
TONIGHT ACROSS NRN NEB AND WRN SD.

...ERN IA/SRN WI INTO NW IL/WRN LWR MI...
SURFACE-BASED INSTABILITY SHOULD REMAIN LIMITED /AOB 500 J PER KG/
OVER THE UPR MS VLY/UPR GRT LKS REGION TODAY...DOWNSTREAM FROM IA
VORT.  BUT IF SUFFICIENT SURFACE HEATING CAN OCCUR...FORCING BY THE
DISTURBANCE...COUPLED WITH RELATIVELY DRY SUB-CLOUD LAYER AND
MODERATE UNIDIRECTIONAL WLY FLOW...MAY SUPPORT THE DEVELOPMENT OF A
LINE OF FORWARD-PROPAGATING STORMS OVER ERN IA/SRN WI. IF SUSTAINED
ACTIVITY DOES INDEED DEVELOP...A CONDITIONAL THREAT WILL EXIST FOR
DAMAGING WIND THIS AFTERNOON INTO EARLY TONIGHT.

...W CNTRL/NW TX...
LEE TROUGH/DRYLINE WILL REMAIN IN PLACE ACROSS W CNTRL AND NW TX
TODAY. AVERAGE SURFACE DEWPOINTS SHOULD BE IN THE LOW 60S EAST OF
THE FEATURE...A BIT MORE MOIST THAN IN PAST DAYS.  THIS MOISTURE
HAS...HOWEVER...TRANSLATED INTO SOMEWHAT GREATER COVERAGE OF
BOUNDARY LAYER STRATOCU.  TEMPERATURES HAVE ALSO WARMED A DEGREE OR
TWO AT MID LEVELS RELATIVE TO RECENT DAYS.  MODERATE SURFACE HEATING
SHOULD...NEVERTHELESS...BOOST AFTERNOON MLCAPE TO AOA 1000 J/KG.

AS PREVIOUSLY NOTED...WV LOOPS DO SHOW A WEAK SRN STREAM IMPULSE NOW
OVER SW TX DRIFTING ENEWD.  BUT THIS DISTURBANCE WILL LIKELY HAVE
MOVED BEYOND THE DRY LINE BY MAX HEATING TIME. GIVEN THE ABOVE
RESERVATIONS...CONFIDENCE IS NOT HIGH FOR THE INITIATION OF DRY LINE
STORMS THIS AFTERNOON. IF STORMS DO DEVELOP...HOWEVER... SETUP WILL
BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL GIVEN STEEP MID LEVEL
LAPSE RATES...RESPECTABLE BOUNDARY LAYER MOISTURE AND 30+ KT DEEP
WNWLY SHEAR.  ANY STORMS THAT DO FORM SHOULD WEAKEN QUICKLY AFTER
SUNSET.

..CORFIDI/TAYLOR.. 04/19/2005

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
WILL PROVIDE DETAILS ON THE TRANSITION.