630
acus01 kwns 170051
swody1
Storm Prediction Center ac 170049
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
0749 PM CDT Wednesday may 16 2012
Valid 170100z - 171200z
..there is a slight risk of severe thunderstorms this evening across parts of
central/northestern Massachusetts and southeastern New Hampshire into southwestern Maine...
..cntrl Massachusetts into southeastern New Hampshire/southwestern Maine...
Latest rapid refresh indicates that boundary layer cape remains
moderately large along a lingering pre-frontal axis of stronger
daytime heating. Perhaps aided by large-scale forcing for upward
vertical motion associated with a significant short wave trough...
the southern portion of which is shifting east of the Great Lakes
region...vigorous convective development with large hail/damaging
wind potential may persist into the 02-03z time frame...before
conditions stabilize with frontal passage/loss of surface heating.
..intermountain west/rockies/plains...
Much of ongoing thunderstorm activity is expected to diminish by the
03-05z time frame as boundary layer stabilization takes place with
the loss of daytime heating. Even though moisture levels are rather
low across the northern plains...models suggest that some additional
thunderstorm development is still possible later tonight...in
association with strengthening Lower/Middle tropospheric warm
advection. Given the plume of very warm elevated mixed layer air
advecting east northeast the north central rockies into the eastern
Dakotas...the best chance for this may be across parts of
northeastern South Dakota into parts of central/southern north
Minnesota toward 08-12z...as a veering low-level jet finally begins
to focus lift east of stronger middle-level capping.
...
With weak upper troughing contributing to convective potential...
scattered vigorous thunderstorm activity continues across the South
Atlantic coast states. However...given the generally weak wind
fields and vertical shear...severe potential still seems
low...particularly with continuing gradual boundary layer
stabilization anticipated this evening.
.Kerr.. 05/17/2012
Mesoscale Discussion
216
acus11 kwns 170042
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 170042
mez000-maz000-nhz000-ctz000-vtz000-170145-
Mesoscale discussion 0827
National Weather Service Storm Prediction Center Norman OK
0742 PM CDT Wednesday may 16 2012
Areas affected...MA/NH/CT/western Maine
Concerning...Severe Thunderstorm Watch 280...
Valid 170042z - 170145z
The severe weather threat for Severe Thunderstorm Watch 280
continues.
Summary...Severe Thunderstorm Watch 280 is scheduled to expire at 01z...but
a localized wind damage/severe hail threat will continue in the
short term /potentially outside of ww 280/ mainly across southern
New Hampshire/adjacent Massachusetts and perhaps far southwest/coastal Maine.
Discussion...a northeast-southwest oriented band of strong/severe
thunderstorms continue to steadily progress eastward across southern
New Hampshire/northern Maine as of 0030z. These storms will gradually encounter
a relatively cooler/more stable boundary layer toward the coast as
per the 00z observed Chatham Massachusetts sounding and observed surface
temperature trends over the past 1-2 hours. Nonetheless...a
localized wind damage/severe hail threat may continue over the next
hour or so /beyond 01z/ given the existing thunderstorm
organization/vertical shear...but likely on an increasingly marginal
basis as thunderstorms otherwise eventually exit the southern New England
coast.
.Guyer.. 05/17/2012
..please see www.Spc.NOAA.Gov for graphic product...
Attention...WFO...gyx...box...aly...
Latitude...Lon 42387332 43217196 44687082 45306973 43567012 42057178
41787325 42387332
