U.S. Severe Weather Forecast (Convective Outlook)

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acus01 kwns 301246 
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Storm Prediction Center ac 301244 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0744 am CDT Thursday Oct 30 2014 


Valid 301300z - 311200z 


..there is a marginal risk of severe thunderstorms across central Texas... 


... 
widely scattered thunderstorms are possible today into tonight 
across parts of Texas...Florida...and the Ozarks to middle 
Mississippi River valley. A few strong storms may be possible across 
parts of central Texas late this afternoon and evening. 


... 
An amplifying large-scale pattern will exist over the Continental U.S.. an 
eastward-shifting upper ridge over The Rockies/High Plains will be 
flanked by an amplifying upper trough over the eastern third of the 
Continental U.S....while an additional trough currently centered near 138w 
gradually approaches the Pacific northwest. A cold front will move 
slowly southward across the Florida Peninsula today...while an additional 
cold front sweeps south-southeastward across much of the 
central/Southern Plains and Ozarks/adjacent MS River Valley. 


..central Texas... 
A modestly moist air mass characterized by 50s/some lower 60s f 
surface dewpoints resides across central/south Texas in the wake of the 
prior frontal passage...with 100mb mean mixing ratios of 12.4/14.3 
g/kg observed in 12z observed soundings from del Rio/Corpus Christi 
respectively. A limited degree of northward moisture transition is 
expected to occur in advance of a fast-moving/south-southeastward 
moving cold front across the Central Plains. With the aid of a weak 
surface low and the approaching cold front...a loosely organized 
triple point should materialize across north-central Texas toward peak 
heating. Although large-scale influences will be weak on the 
anticyclonic side of the polar jet...sufficient frontal 
uplift/isentropic ascent in the presence of a modestly unstable 
boundary layer /750-1250 j per kg MLCAPE/ should contribute to at 
least isolated thunderstorm development by late afternoon/early 
evening. This is well-supported by various traditional deterministic 
guidance in addition to virtually all members of the 00z sseo 
including the WRF-NSSL. 


Given the aforementioned buoyancy...strengthening belt of 
north-northwesterly middle-level winds and strong turning with height 
will contribute to 35-40 knots of effective shear...which could support 
some organized storms including a couple of weak/transient 
supercells. As such...marginal-caliber severe probabilities have 
been introduced for mainly a hail risk late this 
afternoon/evening...with the greatest coverage of southward-moving 
thunderstorms expected after dark. 


... 
A cold front will settle slowly southward across the 
northern/central Florida Peninsula through tonight...while an amplifying 
shortwave trough approaches south Georgia/North Florida. Ongoing thunderstorms 
over the eastern Gulf of Mexico may gradually approach the western 
Florida Peninsula today...while other relatively low-topped storms are 
likely to develop in vicinity of the front across the 
north-Central/Northeast peninsula later this afternoon/early 
evening. Although middle-level lapse rates will be weak...steepening 
low-level lapse rates and 60s f surface dewpoints will contribute to 
as much as 750-1000 j/kg MLCAPE this afternoon. While a 
strong/severe thunderstorm cannot be entirely discounted inland 
/such as kdab general vicinity/...current thinking is that severe 
probabilities remain below 5 percent given a marginal thermodynamic 
environment. 


.Guyer/Bothwell.. 10/30/2014 

Mesoscale Discussion


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acus11 kwns 151721 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 151720 
paz000-mdz000-151945- 


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