####018000595#### PENA01 KWNH 221200 @UHPISF000CN MPDSUM@V2.0@0101700060@12220625@@0NMCGPHMPDP@!' `' ` @ & B7)p&PNAM02@@|NO MDs ARE CURRENTLY IN EFFECT @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 06/22/2025 0530Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @####018002818#### AWUS01 KWNH 220531 FFGMPD VTZ000-NYZ000-221130- Mesoscale Precipitation Discussion 0489 NWS Weather Prediction Center College Park MD 130 AM EDT Sun Jun 22 2025 Areas affected...Northern and Central NY Concerning...Heavy rainfall...Flash flooding possible Valid 220530Z - 221130Z SUMMARY...Strong convective complex over southeast Ontario will be arriving across northern and central NY over the next several hours. Some localized cell-training concerns are expected which may result in some areas of flash flooding early this morning. DISCUSSION...The latest GOES-E IR satellite imagery along with MRMS data shows a well-organized QLCS dropping down across southeast Ontario, with the convective mass associated with a strong shortwave embedded within deep layer west-northwest flow situated around the northeast flank of a deep layer subtropical ridge over the Midwest and Great Lakes region. Very cold convective tops are noted with the southwest flank of the convective complex, with some overshooting tops as cold as about -70C. Strong warm air advection and moisture transport associated with a 50+ kt southwest low-level jet is seen riding up across the lower Great Lakes region and far southeast Ontario, and there is a nose of strong elevated instability aimed into the southwest flank of the convective mass with MUCAPE values of 2000 to 3000 J/kg. The robust moisture and instability transport into far southeast Ontario will begin overspreading areas of northern NY over the couple of hours as the shortwave energy approaches. This coupled with strong effective bulk shear values of 40 to 50+ kts will favor arrival of a well-organized band of convection, with the QLCS losing latitude and dropping southeastward across northern and eventually central NY going through early this morning. Rainfall rates with this activity as it has been traversing Ontario overnight have been well into the 1 to 2 inch/hour range, with some cell-training that has fostered storm totals of 2 to 4 inches. As this activity arrives down across northern and central NY, the southwest flank of the convective mass may continue to be a focus for cell-training as some of the convection becomes aligned more parallel to the deeper layer steering flow. Similar rainfall rates and totals are expected as this QLCS arrives over the next several hours, and this may drive at least some areas of flash flooding. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...ALY...BGM...BTV...BUF... ATTN...RFC...RHA...TAR...NWC... LAT...LON 44977381 44537318 43167351 42377450 42337615 42707711 43227723 43417673 43677638 44447591 44967497 ####018000697#### PENA01 KWNH 221200 @UHPISF000CN MPDSUM@V2.0@0101700060@12220625@@0NMCGPHMPDP@!' `' ` @ & B7)p&PNAM02@@-u{{|||}}~|}{zzz{@@@@@@40489 @@d&MESOSCALE DISCUSSION SUMMARY GRAPHIC @@d& OF ALL VALID MESOSCALE DISCUSSIONS AT @@d& TIME OF PRODUCT CREATION:@@d& ISSUED 06/22/2025 0531Z @@ dNOAA/NWS/NCEP@@d WEATHER PREDICTION CENTER @@d FOR COLOR VERSION SEE: @@d WWW.WPC.NCEP.NOAA.GOV @