SPC Day 1 Thunderstorm Outlook Issued 16Z 20030916


ZCZC SPCSWODY1 ALL
ACUS01 KWNS 161611
SPC AC 161611

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1111 AM CDT TUE SEP 16 2003

VALID 161630Z - 171200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 NNW
ELO 30 NW HIB 10 SE GFK 25 ESE DVL 60 NNW DVL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSW GON 30 W EFK
...CONT... 15 ESE ILM 35 NE EWN 15 ENE ECG ...CONT... 45 SSE CTY 40
NNW DAB.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 WSW HRO 40 NE ADM
15 N FSI 45 E GAG 15 NW SUX 30 NE FOD 10 SW ALO 30 ENE OTM 45 NNE
COU 15 WSW HRO.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 ENE DLH 40 SW FAR
45 N CYS 45 E ASE 20 WNW GUC 15 ENE CNY 15 SW BPI 30 SE IDA 50 ESE
BKE 30 NE RDM 30 N OTH.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 WNW LRD 15 SSE HDO
10 ENE CLL 15 SE BPT.

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT
ACROSS PARTS OF NORTHERN MN AND NORTHEAST ND...

UPPER TROUGH IS SLOWLY DIGGING SOUTHEASTWARD INTO THE
NORTHERN/CENTRAL ROCKIES TODAY...WITH RIDGE DOMINATING THE WEATHER
OVER THE SOUTHEAST STATES.  SURFACE CYCLOGENESIS IS FORECAST TO
OCCUR OVER EASTERN WY/MT THIS AFTERNOON/EVENING...WITH SOUTHERLY LOW
LEVEL WINDS INCREASING OVER THE CENTRAL/NORTHERN PLAINS.  DESPITE
LIMITED MOISTURE...SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THIS
REGION TODAY AND TONIGHT.

...NORTHERN PLAINS AND UPPER MIDWEST...
PRIMARY SURFACE BOUNDARY CURRENTLY EXTENDS FROM LOW IN WY
NORTHEASTWARD ACROSS SD INTO NORTHWEST MN. THIS BOUNDARY WILL LIFT
SLOWLY NORTHWARD TODAY...WITH LOW LEVEL MOISTURE/INSTABILITY
INCREASING ALONG AND SOUTH OF FRONT.  STRONG DAYTIME HEATING IN THIS
AREA SHOULD RESULT IN MLCAPE VALUES OF AROUND 1000 J/KG.  UVVS ARE
EXPECTED TO INCREASE THIS EVENING AS LOW LEVEL JET INTENSIFIES AND
WESTERN TROUGH BEGINS TO APPROACH.  THIS SHOULD LEAD TO SCATTERED
HIGH-BASED THUNDERSTORM DEVELOPMENT IN THE RELATIVELY DRY AIRMASS
NORTH/WEST OF BOUNDARY ACROSS PARTS OF EASTERN MT/WY AND THE WESTERN
DAKOTAS.  THESE STORMS WILL HAVE THE THREAT OF GUSTY WINDS AND HAIL.
 STORMS WILL SPREAD EASTWARD AND INTENSIFY THIS EVENING AS THEY
INTERACT WITH BOUNDARY AND STRONGER LOW LEVEL JET OVER EASTERN
ND/NORTHERN MN.  LARGE HAIL APPEARS TO BE THE MAIN SEVERE THREAT IN
THIS AREA.

...CENTRAL PLAINS...
MODEL GUIDANCE IS CONSISTENT IN THE MAINTAINING A STRONG LOW LEVEL
JET ACROSS PARTS OF KS/MO/OK.  MODEL FORECAST SOUNDINGS IN THIS
REGION INDICATE THAT A MODERATELY UNSTABLE AIRMASS WILL DEVELOP THIS
AFTERNOON...WITH STEEP MID LEVEL LAPSE RATES AND MLCAPE VALUES OVER
2000 J/KG.  SUFFICIENT LOW LEVEL WARM ADVECTION AND RELATIVELY WEAK
CAP MAY RESULT IN ISOLATED HIGH-BASED THUNDERSTORM DEVELOPMENT. 
SOME POTENTIAL EXISTS FOR LARGE HAIL IN STRONGER CELLS.  AREAL
COVERAGE OF SEVERE STORMS SHOULD PRECLUDE A SLIGHT RISK ISSUANCE.

..HART/BANACOS.. 09/16/2003

...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.

$$