U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 021619 
Storm Prediction Center ac 021617 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1117 am CDT Tuesday Sep 02 2014 

Valid 021630z - 031200z 

..there is a slight risk of severe thunderstorms this afternoon and evening over 
parts of PA/NY... 

A few damaging gusts will be possible over much of Pennsylvania and 
New York...mainly this afternoon. Other isolated strong to severe 
storms will be possible over the central appalachian states and 
Tennessee Valley this afternoon...and over parts of Oklahoma and 
Kansas overnight. 

..PA/New York into WV/KY... 
A shortwave trough is evident this morning over the Ohio Valley and 
Great Lakes states...progressing eastward. This feature and an 
associated surface cold front will help to organize scattered 
showers and thunderstorms later today over parts of PA/NY. Forecast 
soundings in this area show rather strong deep-layer westerly flow 
and high precipitable water values...suggestive of a relatively fast-moving line 
of storms along the front capable of isolated strong to damaging 
wind gusts. Visible satellite imagery also confirms this region 
will see substantial heating/destabilization through the day. It 
appears the risk of organized severe storms decreases farther south 
into WV/Kentucky where the upper system has less affect and wind fields 
are slightly weaker. Nevertheless...the strongest cores in this 
region will also pose an isolated threat of wind damage. 

The remnants of a large nocturnal mesoscale convective system continues to affect parts of 
OK/AR...with the leading-edge gust front of the convection extending 
from northeast Arkansas into southeast OK. This boundary will continue to 
sag southward today into a moist and moderately unstable air mass. 
Scattered thunderstorms will likely form here...as well as farther 
northeast into parts of KY/TN. Wind fields are weak and convective 
organization should be limited. However...the strongest storms 
could produce locally gusty winds. 

..OK/Kansas tonight... 
Southerly low level winds are forecast to strengthen significantly 
tonight over the southern/Central Plains. This will lead of a 
region of enhanced warm advection and lift in vicinity of remnant 
outflow boundary of ongoing convection over OK. Present indications 
are that scattered thunderstorms will form near or after sunset in 
northern OK/southern Kansas and drift slowly eastward overnight. A few 
of these storms may be capable of hail and gusty winds. This 
scenario will be monitored today for signs of greater coverage of 
thunderstorms and possible upgrade to slight risk. 

.Hart/Rogers.. 09/02/2014 

Mesoscale Discussion

acus11 kwns 020146 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 020145 

Mesoscale discussion 1661 
National Weather Service Storm Prediction Center Norman OK 
0845 PM CDT Monday Sep 01 2014 

Areas affected...north central/northestern OK...and southeastern Kansas into southwestern MO 

Concerning...Severe Thunderstorm Watch 486...487... 

Valid 020145z - 020315z 

The severe weather threat for Severe Thunderstorm Watch 

Summary...potentially damaging wind gusts...frequent cloud to ground 
lightning and heavy rainfall are expected to become the primary 
convective hazards within the next hour or so. A new severe weather 
watch...or extension in time of ww 486...probably will be needed by 

Discussion...a considerable increase in the number of 
storms/convective coverage has been underway during the past hour or 
so. This appears generally in response to large-scale ascent 
associated with a band of enhanced convergence and warm 
advection...based roughly around 850 mb. Forcing for ascent could 
still increase some with modest strengthening of the southerly 
low-level jet /30-35 knots at 850 mb/ through the 03-05z time 
frame...likely providing the focus for strongest storm development 
near the Kansas/Oklahoma border area...between Bartlesville and 
Joplin. Aided by inflow of seasonably high moisture content 
air...with sizable cape beneath lingering modestly steep middle-level 
lapse rates...the evolution of a small but increasingly organized 
convective system appears possible in the presence of strong 
vertical shear. Heavy precipitation loading and downward Transfer 
of momentum associated with 30 knots deep layer westerly mean flow will 
contribute to increasing potential for downbursts and surface gusts 
at least approaching...if not exceeding...severe limits. 

.Kerr.. 09/02/2014 

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


Latitude...Lon 37849524 37849324 36869295 36659496 36379654 36169748 
36399803 37069754 37849524