U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 021940 
Storm Prediction Center ac 021939 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0139 PM CST Friday Dec 02 2016 

Valid 022000z - 031200z 

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

Isolated severe thunderstorms are possible across portions of south 
Texas late this afternoon into tonight. 


No changes to 1630z. 

.Darrow.. 12/02/2016 

Previous discussion.../issued 1016 am CST Friday Dec 02 2016/ 

..south Texas... 
The latest water vapor loop shows a broad and deep upper trough over 
most of the Continental U.S....while a more progressive shortwave trough digs 
into the southwest states. Middle level winds are forecast to back and 
increase over Texas this afternoon and tonight as the upper trough 
approaches...with southeasterly low level winds also strengthening. 
This will result in enhanced low level warm advection over parts of 
south and West Texas. Model solutions are similar in the depicting 
the development of scattered showers and thunderstorms across the 
region - mainly after dark. Forecast soundings indicate 
sufficiently cool middle level temperatures and vertical shear to pose 
a risk of hail in the strongest cells...along with locally gusty 
winds and perhaps a tornado. The overall severe risk is expected to 
remain marginal. 


Mesoscale Discussion

acus11 kwns 011013 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 011013 

Mesoscale discussion 1861 
National Weather Service Storm Prediction Center Norman OK 
0413 am CST Thursday Dec 01 2016 

Areas affected...northern Maine 

Concerning...heavy snow 

Valid 011013z - 011415z 

Summary...heavy snowfall rates generally in the 1-2 inches per hour 
range are forecast during the 1030-1430 UTC period across northern 
parts of Maine. 

Discussion...radar mosaic early this morning shows a large 
precipitation shield across Vermont/New Hampshire northward into Maine. The 
precipitation is associated with a northeast-migrating middle-level 
shortwave trough located over the Adirondacks and the St. Lawrence 
Valley. Veering and strengthening of flow in the lowest 6-km...per 
kcbw VAD data...implies strong warm air advection and substantial 
isentropic lift atop a cool dome located over northern New England. 
Model guidance suggests frontogenetic forcing will maximize during 
the 11-14 UTC period in the 700 mb-h6 layer coincident with dynamic middle- 
to upper-level forcing via DCVA. 0930 UTC GPS precipitable water 
over southern coastal Maine was around 1 inch...and when coupled with 
the magnitude of upward vertical motion...will probably result in 
liquid-equivalent precipitation rates of 0.10-0.25 inch per hour. 

Rap forecast soundings show a deep isothermal layer generally at or 
slightly below freezing which should support heavy/wet dendritic 
snow. Both experimental omega*pw*rh /oprh/ guidance from the 
rap/NAM and sref calibrated hourly snowfall rates imply rates in the 
1-2 inches per hour range beginning by 11 UTC and ending during the 
14-15 UTC period. 

.Smith.. 12/01/2016 

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


Latitude...Lon 46296780 46067017 46597008 47506936 47386812 46836761