ZCZC SPCSWODY1 ALL
ACUS01 KWNS 151713
SPC AC 151710

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK 
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.

VALID 151630Z - 161200Z

THERE IS A HIGH RISK OF SVR TSTMS THIS AFTERNOON AND EVENING ACROSS
PARTS OF THE TX AND OK PANHANDLES INTO WRN OK / WRN N TX.  THE HIGH
RISK AREA IS TO THE RIGHT OF A LINE FROM 40 SW CDS 10 SE AMA 20 NE
DHT 25 WSW LBL 15 NNW GAG 40 NNE CSM 30 NW FSI 25 WSW SPS 55 WSW
SPS 40 SW CDS.

SURROUNDING THE HIGH RISK...THERE IS A MDT RISK OF SVR TSTMS ACROSS
THE SRN HIGH PLAINS TO THE RIGHT OF A LINE FROM 65 WNW ABI 70 ESE
LBB 25 WNW PVW 45 E TCC 50 SSE LHX 10 S LAA 15 NW GCK 35 ESE DDC 20
SE P28 10 WSW END 35 E SPS 20 NNE SEP 25 WSW ABI 65 WNW ABI.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
45 SW CHS 25 ENE DHN 10 ENE JAN 30 WNW MEM 30 WSW MDH 30 WNW EVV
30 E SBN 10 ESE DTW 20 NE CAK 15 N EKN 10 ESE LYH 40 NNE RWI
20 E ECG.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
15 WSW BGS 55 W LBB 25 S CVS 35 ENE LVS 25 NNW RTN 15 SE COS
15 W LIC 40 WNW GLD 25 ENE BVO 40 E TUL 30 NNW PGO 30 S PRX
15 E ACT 30 SSW JCT 45 ENE P07 15 WSW BGS.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 NNW JHW PSB
15 SSE CXY 20 ENE ACY ...CONT... 25 NW BVE 25 NW LCH 45 ESE CLL
20 ESE SAT 45 NW LRD ...CONT... 10 SE P07 25 W MAF 50 SSE SAF
35 NW INW 45 SSW BCE 35 E DPG 25 SSE ENV 20 SSE OWY 15 NW BOI
65 SE S80 40 WNW MSO 15 SW PUW 40 NE PDX 15 NNW AST ...CONT...
70 NNW DVL 45 ENE MBG 30 E MHN 25 SW EAR 10 E MKC 25 SW MTO
25 SE CGX LAN 35 NNE MTC.

...SYNOPSIS...
STRONG UPPER LOW / VORT MAX AND ASSOCIATED 70 TO 80 KT MID-LEVEL
JET STREAK WILL MOVE EWD OUT OF THE SRN ROCKIES INTO THE SRN PLAINS
THROUGH THE PERIOD.  MEANWHILE...A SECOND SHORT-WAVE TROUGH IS
EXPECTED TO MOVE EWD ACROSS THE OH AND TN VALLEYS / CENTRAL
APPALACHIANS THROUGH THE PERIOD.  

AT THE SURFACE...SWRN U.S. LOW IS FORECAST TO REDEVELOP OVER NERN
NM EARLY THIS AFTERNOON AND THEN MOVE EWD ACROSS THE TX
PANHANDLE...ALONG SWRN EXTENSION OF FRONT MOVING SEWD ACROSS THE OH
VALLEY REGION ATTM.

...SRN PLAINS...
LOCALIZED SEVERE WEATHER OUTBREAK IS EXPECTED THIS AFTERNOON AND
EVENING ACROSS THE SRN HIGH PLAINS REGION.

STRONG UPPER FEATURE CONTINUES MOVING EWD ACROSS THE SRN ROCKIES...
AND IS NOW INVOF THE FOUR CORNERS REGION.  AS THIS FEATURE MOVES
EWD AND SURFACE LOW DEVELOPS IN NERN NM / THE WRN TX PANHANDLE THIS
AFTERNOON...LOW-LEVEL SELY FLOW WILL INCREASE.  AS A RESULT...LOW-
LEVEL MOISTURE WILL ADVECT NWWD INTO THE TX PANHANDLE INTO SERN CO
AND SWRN KS...WHILE DRY LINE MIXES SLOWLY EWD ACROSS THE TRANSPECOS
REGION.  GIVEN STEEP MID-LEVEL LAPSE RATES IN PLACE...AIRMASS WILL
BECOME MODERATELY UNSTABLE AHEAD OF DRYLINE.  EXACT WRN EXTENT OF
MOISTURE / INSTABILITY ACROSS THE TX PANHANDLE IS STILL IN QUESTION
AS THE TENDENCY FOR VERY SHALLOW MOISTURE IN MORNING AMA SOUNDING
TO MIX OUT WILL BE OPPOSED BY DEVELOPING SELY FLOW / MOIST
ADVECTION AHEAD OF DEVELOPING SURFACE LOW.  

AS UPPER FEATURE APPROACHES...IT APPEARS THAT THUNDERSTORMS SHOULD
DEVELOP BY MID AFTERNOON ACROSS FAR NERN NM / THE WRN TX
PANHANDLE INTO SERN CO...AND THEN MOVE EWD AND DEVELOP SWD INTO THE
TX SOUTH PLAINS.  WITH INCREASING LOW-LEVEL SELY FLOW BENEATH
APPROACHING MID-LEVEL JET...WIND FIELD WILL BECOME INCREASINGLY
FAVORABLE FOR SUPERCELLS THROUGH THIS AFTERNOON...SUGGESTING RAPID
EVOLUTION OF CONVECTION INTO SEVERE / SUPERCELL STORMS.  DEGREE OF
LOW-LEVEL MOISTURE AND SHEAR AHEAD OF DRYLINE / INVOF SURFACE WARM
FRONT WHICH SHOULD SHARPEN THIS AFTERNOON ACROSS THE TX PNHDL / RED
RIVER VALLEY REGION SUGGESTS A THREAT FOR TORNADOES -- A FEW
SIGNIFICANT.  VERY LARGE HAIL AND DAMAGING WINDS WILL ALSO BE
POSSIBLE.  SEVERE THREAT SHOULD EXTEND AS FAR N AS SERN CO / SWRN
KS...AND SWD ALONG THE DRYLINE TOWARD THE TX BIG BEND.

OVERNIGHT...STORMS SHOULD INCREASE IN COVERAGE OVERNIGHT ACROSS SRN
KS / OK / THE RED RIVER VALLEY AREA AS LOW-LEVEL JET INCREASES TO
50 KTS...RESULTING IN STRONG WARM ADVECTION NEAR AND NORTH OF
SURFACE BOUNDARY.  LARGE MCS APPEARS LIKELY...WITH A CONTINUED
THREAT FOR HAIL / DAMAGING WINDS AND ISOLATED TORNADOES AS THE
STORMS MOVE EWD.

...OH AND TN VALLEYS / SERN CONUS...
SURFACE BOUNDARY IS MOVING SEWD ACROSS THE OH VALLEY ATTM...AND
SHOULD CONTINUE SEWD INTO THE TN VALLEY THROUGH THE PERIOD. 
AIRMASS AHEAD OF THIS BOUNDARY IS RELATIVELY MOIST...AND WILL
CONTINUE TO DESTABILIZE THROUGH THE AFTERNOON.

AS MID-LEVEL FEATURE NOW CENTERED OVER NRN IN / SRN LOWER MI
CONTINUES EWD...SHORT-WAVE RIDGING SHOULD SLOWLY SPREAD EWD ACROSS
THE MS VALLEY.  HOWEVER...EAST OF THE MS VALLEY / AHEAD OF COLD
FRONT...WIDESPREAD CONVECTION IS EXPECTED.  THUNDERSTORMS ARE ALSO
POSSIBLE BEHIND THE FRONT / JUST AHEAD OF THE UPPER LOW ACROSS NRN
IN / NRN OH / SRN LOWER MI.  STORMS WILL LIKELY DEVELOP / SPREAD AS
FAR E AS THE MID-ATLANTIC REGION THROUGH THE AFTERNOON AND INTO
THIS EVENING.

WITH 50 KT WSWLY MID-LEVEL JET STREAK FORECAST TO MOVE SEWD ACROSS
THE TN VALLEY...DEEP-LAYER WIND FIELD WILL BE SUPPORTIVE OF
ORGANIZED STORMS / STORM CLUSTERS...WITH HAIL AND DAMAGING WINDS
EXPECTED.  THREAT SHOULD CONTINUE AS STORMS DEVELOP / SPREAD EAST
OF THE APPALACHIANS THROUGH THE PERIOD.

...FL...
MODERATE /AROUND 7 C/KM/ LAPSE RATES WERE OBSERVED BY MORNING TBW
ROAB ABOVE MOIST /LOW 70S SURFACE DEWPOINTS/ LOW-LEVEL AIRMASS
ACROSS THE SRN 2/3 OF THE FL PENINSULA.  WITH ENHANCED /AROUND 40
KT/ MID-LEVEL FLOW FORECAST TO MOVE ACROSS THE NRN HALF OF THE
PENINSULA THIS AFTERNOON...THERMODYNAMIC AND KINEMATIC ENVIRONMENT
APPEARS SUPPORTIVE OF LOCALLY DAMAGING WINDS / HAIL WITH A FEW OF
THE STRONGER STORMS.  GREATEST THREAT FOR CONVECTIVE DEVELOPMENT
APPEARS TO EXIST ALONG WSW-ENE SURFACE BOUNDARY FROM ROUGHLY TBW TO
MLB -- AND INVOF EAST AND WEST COAST SEA-BREEZE BOUNDARIES ACROSS
THE SRN 2/3 OF THE PENINSULA.  ACTIVITY SHOULD DIMINISH THIS
EVENING WITH THE LOSS OF DAYTIME HEATING.

...NRN HIGH PLAINS...
MID-LEVEL TROUGH AND ASSOCIATED JET STREAK IS FORECAST TO MOVE
ACROSS WRN AND INTO NERN MT DURING THE LATTER HALF OF THE PERIOD...
ALLOWING LOW-LEVEL JET TO DEVELOP / INCREASE ACROSS THE HIGH
PLAINS.  HOWEVER...LOW-LEVEL MOISTURE /SURFACE DEWPOINTS IN THE MID
40S/ WILL REMAIN LIMITED...SUGGESTING MINIMAL INSTABILITY THROUGH
THE PERIOD.  A COUPLE OF HIGH-BASED STORMS MAY DEVELOP ACROSS N
CENTRAL / NERN MT AND SPREAD EWD INTO NWRN ND DURING THE LATTER
HALF OF THE PERIOD WITH AN ASSOCIATED THREAT FOR MARGINALLY-SEVERE
HAIL OR A LOCALLY DAMAGING GUST...BUT OVERALL THREAT APPEARS TO BE
QUITE LIMITED / BELOW SLIGHT RISK THRESHOLDS. 
 
..GOSS.. 05/15/03

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