SPC AC 301726

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1226 PM CDT Tue May 30 2017

   Valid 311200Z - 011200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN
   VIRGINIA INTO SOUTHERN NEW ENGLAND...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
   CENTRAL PLAINS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHWEST
   TEXAS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
   IDAHO INTO WESTERN MONTANA...

   ...SUMMARY...
   Sporadic marginally severe hail or wind is possible Wednesday across
   parts of the Northeast and Mid Atlantic, the central Plains,
   southwest Texas, and Idaho into western Montana on.

   ...Synopsis...
   An upper low will remain centered over Hudson bay with broad area of
   strong cyclonic flow aloft from the Great Lakes across the
   Northeast. To the west, an upper ridge axis will gradually shift
   east across the Rockies, with a meridional 50 kt southerly midlevel
   jet max moving across ID and MT. To the south, weak upper
   troughiness will exist across northern Mexico into the southern High
   Plains.

   At the surface, high pressure will settle in across the mid MS into
   the OH and TN valleys, with a weak lee trough from MT into the
   central High Plains. A quasi-stationary front will exist from the
   lower Ohio Valley northwestward across NE, with mainly 50s dewpoints
   across the central Plains. More substantial low-level moisture will
   remain across TX eastward across the Gulf Coast with upper 60s to
   lower 70s. 

   ...Northeast CO/Western NEB across KS and into western MO and
   northeast OK...
   Strong heating will occur south of the boundary, which will steepen
   lapse rates dramatically with cold air aloft present. While
   dewpoints may only reach the mid/upper 50s, MUCAPE on the order of
   1500-2000 J/kg will develop. Generally weak southeasterly low level
   flow with modest northwesterly midlevel flow may be enough for a few
   longer lived cells, as well as small bowing structures. Storms are
   expected to form over KS/MO by late afternoon, as well as across
   CO/NEB in the upslope region. There may be a small area worthy of a
   Slight risk in later outlooks, perhaps across KS or MO where a
   cluster of wind or hail is possible.

   ...Eastern VA into the Northeast...
   Substantial mid to upper level flow will exist across the region,
   but the focus for development along a surface trough will be weak.
   Alone and ahead of this trough, 50s dewpoints will be common, with
   60s from southeast PA into VA. Strong heating will eventually
   destabilize the entire area, with no convective inhibition by
   afternoon. One area of initiation will likely be across central NY
   into PA along the wind shift. Long hodographs would support
   splitting cells and/or wind depending on the amount of outflow. 

   To the south, early showers or storms are expected over the OH
   valley, and this area of disturbed weather will shift eastward
   across the Appalachians by late afternoon. Any ongoing activity may
   re-energize as it encounters greater instability, and/or possible
   outflow could help instigate new development farther east. Marginal
   hail and wind will be possible.

   ...Southwest TX...
   Southeasterly surface flow will be maintained which will keep the
   air mass relatively moist. Relatively cool temperatures aloft will
   also exist due to the weak upper trough, with -10 C around 500 mb.
   Daytime heating will result in around 1500-2000 J/kg MUCAPE by
   afternoon, with scattered thunderstorms likely. Westerly flow aloft
   will be weak, but when juxtaposed atop the surface southeasterlies,
   may yield enough shear for some multicellular clusters capable of
   hail and localized severe wind gusts. Depending on storm coverage
   and intensity, some of the outflow could affect the El Paso area,
   although instability will be weaker there.

   ...ID into western MT...
   A deepening surface trough will be coincident with the advancing 50
   kt  meridional midlevel wave. Cooling aloft and heating will result
   in steep lapse rates and will maximize instability despite low
   levels of moisture. Modest mean wind speeds may be enough for a few
   northeastward moving bows with wind, while veering winds with height
   in the low-levels suggest perhaps a few lone cells capable of hail.

   ..Jewell.. 05/30/2017

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z