U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 210048 
Storm Prediction Center ac 210046 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0746 PM CDT Monday Oct 20 2014 

Valid 210100z - 211200z 

..no severe thunderstorm areas forecast... 

isolated to widely scattered thunderstorms will continue this 
evening across parts of the middle and upper Ohio Valley...and across 
the South Florida vicinity. Gradually weakening convection will 
also continue early this evening across the New 
Mexico/Arizona/western Texas vicinity. Finally...showers and 
occasional/embedded lightning strikes will persist across portions 
of the Pacific northwest/northern California area. 

Slow progression of the amplified upper flow field over the U.S. 
/Consisting of a trough moving onshore from the eastern Pacific and a 
Second Crossing the eastern states/ will continue overnight. Showers 
and a few thunderstorms are ongoing over the Ohio vicinity at this time in vicinity of 
the axis of the upper trough...and may continue for the next few 
hours. Likewise...isolated storms may persist in the short term 
over parts of southern Florida and the Keys. 

Farther west...showers and scattered thunderstorms continue from parts 
of eastern nm eastward to western portions of Texas...near a weakening cut-off low 
lingering across southeastern Arizona/southwestern nm. A diurnal decrease in convective 
intensity/lightning activity will continue over the next few hours. 

Finally...showers and a few embedded thunderstorms will continue 
spreading across the northern California/Pacific northwest vicinity this evening as the western 
upper trough continues to move onshore. 

.Goss.. 10/21/2014 

Mesoscale Discussion

acus11 kwns 151721 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 151720 

Mesoscale discussion 1899 
National Weather Service Storm Prediction Center Norman OK 
1220 PM CDT Wednesday Oct 15 2014 

Areas affected...central Maryland into southeastern PA 

Concerning...severe potential...watch unlikely 

Valid 151720z - 151945z 

Probability of watch issuance...20 percent 

Summary...an isolated strong wind gust or brief/weak tornado cannot 
be ruled out with storms as they develop northward from Maryland into southeastern PA. 

Discussion...an isolated strong cell with substantial vertical 
development continues to propagate northward along a north-S oriented boundary 
which extends into PA and links with an existing front across eastern PA 
which currently separates the more moist/unstable air to the southeast. 

This particular storm has had a persistent and broad circulation 
with it...but nothing particularly strong or tight probably due to 
weak low-level buoyancy/acceleration. While deep-layer flow is 
strong above the ground...most of the shear is relegated to the 
near-surface layer and other cells away from the outflow boundary 
have shown little if any shear. Therefore...any wind/tornados threat is 
expected to be brief...short-lived and isolated...and a watch is not 

.Jewell/corfidi.. 10/15/2014 

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


Latitude...Lon 39157664 39007677 38987688 39067699 39267696 39617690 
40007679 40347640 40457615 40407593 40137594 39617620