SPC AC 091943

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0243 PM CDT Tue Aug 09 2022

   Valid 092000Z - 101200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
   AND EVENING ACROSS PARTS OF CENTRAL OREGON AND PARTS OF THE NORTHERN
   MID ATLANTIC INTO SOUTHERN NEW ENGLAND...

   ...SUMMARY...
   An isolated supercell or two posing a risk for severe wind and hail
   is possible late this afternoon near the eastern slopes of the
   Oregon Cascades.  A few strong storms may still impact parts of the
   Mid Atlantic into southern New England, with potential to produce
   locally damaging wind gusts into early evening.

   ...20Z Update...
   Some adjustments to categorical and probabilistic lines have been
   made, mainly to account for the slow progression of synoptic and
   sub-synoptic features.

   ...Oregon...
   It still appears that the environment is becoming at least
   conditionally supportive of supercell development in a narrow
   corridor to the east of the Oregon Cascades, as a lower/mid
   tropospheric cyclone offshore of the northern California coast
   slowly migrates northward.  

   Based on latest NAM and Rapid Refresh soundings, low-level
   moistening associated with preceding convective precipitation,
   coupled with ongoing insolation, might contribute to mixed-layer
   CAPE in excess of 1500 J/kg, in a relatively confined area near and
   south through west of the Redmond/Bend vicinities within the next
   few hours, as deep-layer shear strengthens.  Given the isolated
   nature of the threat, probably limited to one or perhaps two
   sustained supercells, severe weather probabilities are being
   maintained at 5 percent.  However, these could pose a risk to
   produce large hail and potentially damaging wind gusts.

   ..Kerr.. 08/09/2022

   .PREV DISCUSSION... /ISSUED 1148 AM CDT Tue Aug 09 2022/

   ...Northeast States...
   A surface cold front is analyzed this morning from central New
   England into central PA.  This front will sag southeastward today
   into a hot/moist low-level environment with temperatures in the 90s
   and dewpoints in the 70s.  Forecast soundings show weak mid-level
   lapse rates and warm temperatures aloft, which should be negative
   factors for convective coverage and intensity.  Nevertheless, at
   least isolated thunderstorms are expected to form on the front later
   today, with the strongest cells posing a risk of locally damaging
   wind gusts.  

   ...Central OR...
   A large upper low is present off the coast of northern CA today,
   with rather strong southerly deep-layer flow extending northward
   across much of western and central OR.  12z model guidance continues
   to show multiple waves of convection affecting the MRGL risk area
   through this evening, where sufficient CAPE and deep-layer shear
   will be present for a few organized storms.  The main threat appears
   to be locally damaging wind gusts in pockets of stronger heating,
   but an isolated supercell or two cannot be ruled out, with an
   associated risk of gusty winds or hail.

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