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acus01 kwns 161546
swody1
Storm Prediction Center ac 161544
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
1044 am CDT Wednesday may 16 2012
Valid 161630z - 171200z
..there is a slight risk of severe thunderstorms over parts of New York/PA and western
New England...
..northeast states...
A strong upper trough is rotating eastward across the Great Lakes
region and Ontario this morning...while a 70+ knot middle level jet
rounds the base of the trough and noses into NY/VT. At the
surface...a cold front extends from Northern Ohio into Lake Ontario
with a pre-frontal boundary across central New York. Present indications
are that both boundaries will become convectively active later today
with a threat of large hail and damaging winds across portions of
eastern PA/New York and western New England.
Visible satellite trends suggest that the first convection may form
along the pre-frontal trough over central New York into northeast PA.
Strong heating will promote steep low level lapse rates...and
dewpoints in the 50s to lower 60s will help yield MLCAPE values of
1000-2000 j/kg. Storms that form will be in an environment of
sufficient deep layer effective shear for supercell structures
capable of large hail and damaging winds. Storms will likely spread
eastward across parts of Vermont/New Hampshire and western Massachusetts/CT before weakening
this evening. Present indications are that southerly onshore flow
will limit destabilization in areas farther east...and across the
NYC area.
..eastern Carolinas...
Scattered thunderstorms are expected to form once again today along
the seabreeze of eastern SC/NC. Ample low level moisture and
sufficient southwesterly flow aloft may result in a few intense
cells capable of hail and gusty/damaging winds.
.Hart/Smith.. 05/16/2012
Mesoscale Discussion
058
acus11 kwns 161627
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 161627
vtz000-maz000-nyz000-paz000-161830-
Mesoscale discussion 0824
National Weather Service Storm Prediction Center Norman OK
1127 am CDT Wednesday may 16 2012
Areas affected...much of central and eastern New York...VT...nern PA
Concerning...severe potential...watch likely
Valid 161627z - 161830z
Probability of watch issuance...95 percent
Summary...storms will develop across the area over the next few
hours...possibly in several locations at once. Large hail and a few
damaging wind gusts are likely.
Discussion...visible imagery shows cumulus fields expanding over much of
the area. The first is along the cold front from northwestern PA into western
New York...but instability is currently low with dewpoints mixing into the
40s f. Farther east...another band of clouds was persisting from southern
Quebec into northern and central New York...on the edge of the advancing upper
vorticity. The third area was over southeastern New York and Vermont...near the surface
Theta-E axis where MUCAPE was approaching 1500-2000 j/kg.
With continued heating and little cin...storms will likely form by
18-19z. The strongest forcing will be near the front...but other
storms may form farther east in the instability axis. With favorable
deep layer flow and increasing speed shear with height...supercells
will be likely capable of large hail...perhaps up to Golf Ball size.
A wind threat will also be present...perhaps more with the frontal
activity where storm Mode could benefit form merged outflows. The
tornado threat should be relatively low with weak flow in the lowest
2km...but...winds will veer with height and could result in a
weak...brief spin-up.
.Jewell/Hart.. 05/16/2012
..please see www.Spc.NOAA.Gov for graphic product...
Attention...WFO...btv...aly...bgm...buf...ctp...
Latitude...Lon 41787725 42467691 43027599 44177481 45037402 45077239
44907202 44267222 43287253 42387333 41897365 41677450
41587499 41427608 41597687 41787725
