SPC Jun 30, 2017 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1113 AM CDT Fri Jun 30 2017

Valid 301630Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
OH VALLEY...LOWER GREAT LAKES...INTO NEW ENGLAND...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
OKLAHOMA...NORTH TEXAS...AND WESTERN ARKANSAS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
SOUTHERN PLAINS...INTO THE MID MISSISSIPPI VALLEY...THEN EASTWARD TO
NEW ENGLAND...

...SUMMARY...
Severe thunderstorms are possible this afternoon over parts of
Oklahoma, spreading into parts of north Texas and western Arkansas
this evening.  A few severe storms may also affect parts of New
York, northeast Pennsylvania, and New England later today.  Finally,
strong to severe storms will be possible over parts of the Ohio
Valley and Lower Great Lakes Region.  Damaging wind gusts and
occasional severe hail are the primary threats.

...Northeast...
The morning water vapor loop shows a weak shortwave trough moving
across western NY/PA.  This feature will track eastward across New
England today, providing subtle lift and organization for scattered
showers and thunderstorms.  Clouds are thinning ahead of the system
over eastern NY/PA and much of New England, where surface
temperatures are forecast to warm to near 80F with dewpoints in the
60s.  Moderate CAPE values will support vigorous updrafts with 35-45
knots of effective shear helping storm organization.  The stronger
cells in this region will pose a risk of locally damaging wind gusts
and some hail.  

...OK/TX/AR...
A large nocturnal MCS continues to dissipate at it moves
southeastward across AR.  Strong heating along the western flank of
this system will result in a very unstable air mass across central
and southern OK this afternoon, where steep mid level lapse rates
and dewpoints in the 70s are present.  Scattered thunderstorms are
expected to form in this zone, drifting slowly southeastward this
evening into parts of western AR and north TX.  Thermodynamic
parameters will favor the risk of large hail and damaging wind
gusts.  

...OH Valley...
The northeastern flank of the aforementioned dissipating MCS is
moving into southern IL.  Pockets of moderate CAPE will form ahead
of the remnant boundaries, promoting the development of scattered
afternoon strong thunderstorms.  Vertical shear is not particularly
strong in this area, but residual forcing from the
convectively-induced upper feature may be sufficient for a few
severe storms capable of damaging winds and hail.

...Northeast NM...
Most CAM solutions suggest a small cluster of thunderstorms tracking
southeastward across northeast NM this afternoon and evening, posing
a risk of isolated hail and gusty winds.

..Hart/Dean.. 06/30/2017

Read more

from SPC Forecast Products http://ift.tt/wWCv9s