U.S. Severe Weather Forecast (Coup d'œil sur la convection)

Day Three

acus01 kwns 171631 
Storm Prediction Center ac 171629 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1029 am CST Tue Jan 17 2017 

Valid 171630z - 181200z 

..there is a marginal risk of severe thunderstorms across south 

Isolated severe thunderstorms may develop across parts of south 
Texas, mainly this evening and overnight. Severe hail, locally 
damaging winds, and/or a brief tornado are possible. 

..south Texas... 
A northeast/southwest-oriented front has now essentially stalled 
across west-central la and southeast/south Texas (roughly 70-90 miles 
inland from the coast). A subtle frontal wave was noted in 
mid-morning analysis across far south Texas (brush country vicinity) 
with a moist air mass (near 70 f surface dewpoints) located along 
and south/southeast of the front. 

Late morning water vapor satellite imagery features an amplifying 
trough over northeast Mexico, with an embedded shortwave impulse 
expected to reach far West Texas by mid-afternoon and parts of 
northwest Texas late tonight. DPVA and isentropic ascent focused 
near/north of the surface front should lead to an increase in 
scattered thunderstorms late this afternoon and especially into 

While low-level moisture will remain rich near the front, relatively 
warm upper-level temperatures should limit total buoyancy. Even so, 
a moist air mass, in conjunction with 35-45 kt effective shear and 
modestly strong/curved low-level hodographs (100-200 m2/s2 0-1 km 
srh), may yield weak/transient supercells near the surface front, 
where locally damaging winds and/or a brief tornado could occur. 
Otherwise, isolated marginally severe hail should be the main hazard 
this evening/overnight with a few of the stronger storms to the 
north of the surface front. 

.Guyer.. 01/17/2017 


Mesoscale Discussion

acus11 kwns 171610 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 171610 

Mesoscale discussion 0064 
National Weather Service Storm Prediction Center Norman OK 
1010 am CST Tue Jan 17 2017 

Areas affected...from central New York into parts of the north 

Concerning...freezing rain 

Valid 171610z - 172215z 

Summary...areas of mainly light freezing rain are expected to 
develop across central and northern New York today. 

Discussion...latest surface analysis at 16z shows sub-freezing 
temperatures from central into northern NY, with several areas 
colder than forecast by rap or NAM point forecast soundings. This is 
resulting in ongoing freezing rain along a Syracuse Johnson City 
line currently. 

Aloft, an area of warm advection will persist ahead of a weak 
shortwave trough, with the 850 mb freezing line well to the 
northeast of the discussion area. Therefore, precipitation should 
remain liquid with either rain or freezing rain, depending on the 
surface temperature. Despite some diurnal warming, a saturating 
column should result in cooling, with a few pockets of sub-freezing 
temperatures remaining especially in higher elevations. 

.Jewell.. 01/17/2017 

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


Latitude...Lon 42867618 43357653 43677655 44037685 44287660 44437588 
44227467 43957406 43797380 43357393 42817368 42577401 
42907488 42957519 42827550 42607577 42737609 42867618