U.S. Severe Weather Forecast (Convective Outlook)

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Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1201 am CDT Thursday Oct 23 2014 


Valid 231200z - 241200z 


..no severe thunderstorm areas forecast... 


... 
low chances for isolated thunderstorms are forecast across the 
Pacific northwest...far South Florida...and parts of coastal New 
England. Severe weather is not expected. 


... 


Thunderstorm chances are expected to remain low across the Continental U.S. 
Thursday as limited buoyancy will be present where favored regions 
of ascent are expected. Large scale pattern will become 
increasingly hostile towards moist deep convection as offshore flow 
intensifies across the eastern part of the U.S. 


..coastal New England... 


Elevated convection is expected to persist within warm advection 
zone on back side of exiting cyclone. Early in the period moist 
ascent within the 850-700mb layer should contribute to weak 
convection that could attain heights necessary for lightning 
discharge. However...subsidence should increase after 18z and 
threat of isolated thunderstorms is expected to decrease during the 
afternoon. 


..South Florida... 


Frontal zone will stall across The Straits as southern influence of 
secondary short-wave trough approaches the Florida Peninsula late in the 
period. Weak warm advection along/north of this wind shift should 
contribute to ascent necessary for weak convection capable of 
producing isolated lightning. 


..Pacific northwest... 


Profiles will cool across the Pacific northwest as cold front moves inland 
during the morning hours. Forecast soundings along the Washington coast 
suggest surface-based parcels could reach levels as high as 6km...more 
than adequate for lighting production. Greatest risk along the 
coast will be within Post-frontal airmass. Farther inland...a few 
storms could form along cold front as it progresses across eastern Washington 
into far western Montana. 


.Darrow/marsh.. 10/23/2014 






Mesoscale Discussion


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Storm Prediction Center mesoscale discussion 151720 
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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 
expected. 


.Jewell/corfidi.. 10/15/2014 


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


Attention...WFO...phi...ctp...lwx... 


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