U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 131614 
Storm Prediction Center ac 131612 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1012 am CST Sat Feb 13 2016 

Valid 131630z - 141200z 

..no severe thunderstorm areas forecast... 

isolated thunderstorms with gusty winds may occur this afternoon and 
evening over parts of the northern High Plains. 

..synoptic setup... 
Large-scale pattern will somewhat deamplify through sun as last 
significant shortwave impulse rounds base of eastern U.S trough and Flat 
Ridge progresses from The Rockies into the plains/MS valley. Upstream 
shortwave disturbance now over Idaho should further devolve as it 
shears east-southeast across the northern High Plains this evening...and reaches SW Minnesota/western 
Iowa early sun. 

Arctic surface high will continue slowly east from the MS valley into the 
Appalachians...while increasing westerly flow aloft and dynamic support 
encourage further Lee troughing over the northern High Plains. The trough 
should progress east/southeast into central portions of the Dakotas and Nebraska by 
12z sun...but likely without assuming a significant baroclinic 

..nrn High Plains this aftn/eve... 
Downslope flow and surface heating in wake of departing high-level 
conveyor belt cloud band will yield seasonably warm conditions from 
southern Montana southeastward into the Black Hills later today. At the same 
time...mid-lvl lapse rates and ascent will increase over region with 
the continued east-southeast movement of Idaho upper impulse. The leading edge of 
this destabilization/forcing is now over SW Montana and should reach southeast 
Montana/NE Wyoming by middle-late afternoon. Coupled with low-level uplift along Lee 
trough...setup may promote development of scattered boundary-layer based 
convection sufficiently deep to yield occasional thunder. Given 40+ 
knots unidirectional west-northwest flow likely to be present at the top of the 
mixed layer...potential will exist for convectively enhanced surface 
gusts. Sustained/organized severe gusts are...however...not expected. 

.Corfidi/Dean.. 02/13/2016 


Mesoscale Discussion

acus11 kwns 081731 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 081730 

Mesoscale discussion 0094 
National Weather Service Storm Prediction Center Norman OK 
1130 am CST Monday Feb 08 2016 

Areas affected...portions of eastern Massachusetts...far eastern New Hampshire...RI...ern CT...and 
eastern Long Island 

Concerning...heavy snow 

Valid 081730z - 082230z 

Summary...heavy snowfall...with rates of 1 inch/hour common...will 
likely continue until around 22z. Blizzard conditions will remain 
likely across southeastern Massachusetts...including the cape and adjacent islands. 

Discussion...radar imagery as of 1715z across the region depicts 
several bands of ongoing moderate to heavy snow associated with a 
stacked upper/surface low east-southeast of the New England coast. Tendency will be 
for these mesoscale bands to slowly shift eastward towards the coast 
through 22z as the upper/surface low continue quickly northeastward and away from 
the mesoscale discussion area. Across western portions of MA/CT...one of these mesoscale 
bands is struggling to produce any more than moderate snow per surface 
observations and reported snow totals. This may be due to an 
intrusion of dry low-level air evident on the 12z kgyx sounding and 
in recent surface dewpoints at or below 10 degree f located in this area. 

Further east across the discussion area...surface dewpoints are generally 
higher...and a strong northerly/northeasterly fetch off the Atlantic should 
encourage higher snowfall rates around 1 inch/hr. A strong pressure 
gradient and northeasterly low-level jet...particularly over southeastern Massachusetts 
including the cape/islands...will continue to promote near-blizzard 
to blizzard conditions across this region. Recent surface observations 
indicate reductions in visibility at or below 1/4 Michigan with heavy snow and 
sustained winds of 20-35 knots...with gusts up to 45 knots at kack. 

.Gleason.. 02/08/2016 

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


Latitude...Lon 40707292 41867240 42637167 43077081 42987055 42607052 
42077000 41666983 41196992 41197085 41027180 40817237