U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 021251 
Storm Prediction Center ac 021249 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0749 am CDT Thursday Oct 02 2014 

Valid 021300z - 031200z 

..there is a slight risk of severe thunderstorms from central and East Texas north-northeast into 
the Ozarks...mid-MS and lower Ohio valleys... 

Widespread thunderstorms are expected today through early Friday 
along and ahead of a cold front moving east across the southern and 
Central Plains into the middle-Mississippi and Tennessee valleys. The 
storms should organize into lines and likely will produce strong to 
damaging wind gusts...hail...and perhaps a couple tornadoes. The 
greatest severe threat will extend from northeast Texas and eastern 
Oklahoma into Arkansas and the Ozarks. 

..synoptic setup... 
Pattern will become more amplified across the Continental U.S. This period as 
potent southern rockies shortwave trough ejects east...and later NE...across 
the Southern Plains and lower MS valley ahead of upstream jet streak now moving 
southeast across Alberta. The Rockies impulse should reach central OK this evening 
and southern Illinois by 12z Friday as a larger-scale trough evolves over the 
plains/MS valley. 

At the surface...elongated low over the central/Southern Plains should track 
slowly east into MO and western Arkansas this evening before deepening and 
accelerating north-northeast to Lake Michigan early Friday. Cold front trailing SW from the 
low will be the main focus for thunderstorm development through the 
period...with additional storms likely to persist in pre-frontal warm air advection 
zone extending east-northeast into the mid-MS/lower Ohio valleys. 

..srn plains/lower MS valley into middle MS/lower Ohio valleys today through early 

Very moist air /pw around 1.75/ now over eastern portions of the Southern 
Plains and lower MS valley will spread farther north-northeast into the 
mid-MS...TN...and Ohio valleys later today and tonight as deep south-southwest to southwesterly 
flow backs and strengthens and of southern rockies upper impulse. 

Thunderstorms now over eastern OK and western/central MO are forming within 
pre-frontal warm conveyor belt. This activity should persist through 
later this morning and may pose a sporadic risk of locally damaging 
wind/hail given access to relatively steep middle-level lapse rates and 
40+ knots southwesterly deep shear. Farther west...storms in central Kansas/far S central 
Nebraska are associated with leading edge of a band of ascent loosely 
tied to The Rockies upper trough. These storms could pose a severe hail 
risk eastward into NE Kansas and perhaps northwest MO /ref mesoscale discussion 1793/...before the 
ascent band moves farther east beyond narrow...elevated eml plume now 
supporting the convection. 

Toward midday and through the afternoon...additional thunderstorms are expected 
to form with surface heating along and ahead of accelerating central/Southern 
Plains cold front. Combination of steep middle-level lapse rates and rich 
low-level moisture with 40-50 knots...unidirectional...swly 700-500 mb 
flow and increasing forcing for ascent suggests that initial 
sustained storms/supercells should fairly quickly merge into an 
extensive broken squall line from the MO Ozarks southwestward into central Texas. While a 
couple tornadoes cannot be ruled out...and large hail could occur in 
eastern OK and Texas...the main severe threat should become damaging wind as setup 
will be favorable for embedded lewps/bows. This activity should 
continue east/southeast into the lower MS and Tennessee valleys tonight through early 
Friday...with a continuing risk for damaging wind and perhaps a brief 
tornado or two. 

.Corfidi/cohen.. 10/02/2014 

Mesoscale Discussion

acus11 kwns 021200 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 021159 

Mesoscale discussion 1793 
National Weather Service Storm Prediction Center Norman OK 
0659 am CDT Thursday Oct 02 2014 

Areas affected...northestern Kansas and far southeastern Nebraska into southwestern Iowa/northwestern MO 

Concerning...severe potential...watch possible 

Valid 021159z - 021300z 

Probability of watch issuance...40 percent 

Summary...convective increase appears somewhat likely over the next 
couple of hours...with associated severe risk possibly becoming 
sufficient to warrant consideration of ww issuance. 

Discussion...latest radar imagery shows a well-organized/intense 
storm moving northeastward into cloud Colorado. Kansas at this time...on the leading edge of 
enhanced large-scale ascent spreading across the western half of Kansas per 
latest WV imagery...ahead of a vorticity maximum moving eastward out of southwestern Colorado. 
The storm is elevated above a cool boundary layer west of the surface 
cold front...on the western fringe of the main cape axis and within a 
kinematic environment sufficient for organized/rotating updrafts. 
Potential for additional increase in storm coverage is apparent...as 
increasing ascent overspreads this area. While severe risk would 
likely remain confined to large hail...eventual coverage of said 
threat could warrant consideration of new ww issuance. 

.Goss/corfidi.. 10/02/2014 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 38829815 39659743 40519623 40819530 40849407 39879384 
39049545 38839710 38829815