SPC Mesoscale Discussion
SPC MD 1345
MD 1345 CONCERNING TORNADO WATCH 432... FOR EASTERN IL...WESTERN/NORTHERN IN...FAR SOUTHWEST LOWER MI
Mesoscale Discussion 1345 NWS Storm Prediction Center Norman OK 1057 AM CDT Wed Jun 18 2025 Areas affected...eastern IL...western/northern IN...far southwest Lower MI Concerning...Tornado Watch 432... Valid 181557Z - 181800Z The severe weather threat for Tornado Watch 432 continues. SUMMARY...Severe threat should increase substantially through mid-afternoon as an arc of storms intensifies to the east-northeast from central Illinois. A few tornadoes, scattered damaging winds, and isolated severe hail will remain possible. Downstream tornado watch issuance is anticipated to the northeast of Ww 432. DISCUSSION...While the primary surface cyclone and attendant MCV are centered near the northeast MO/west-central IL border area, a downstream arc of increasing deep convection is expected to strengthen across central IL. With mid 70s surface dew points common across southern IL/IN, a pronounced MLCAPE gradient is setting up from south to north. A compact belt of strong 700-500 mb southwesterlies in the LSX VWP, recently sampled by the ILX VWP as well, should support a broken band of supercells within this leading arc as it spreads northeast. The potential for tornadoes has increased and a 10 percent tornado probability will be added in the 1630Z D1 Outlook. The LSX VWP also indicates low-level SRH diminishing behind this leading arc, but some tornado threat should linger near the immediate MCV/surface low. ..Grams/Hart.. 06/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IWX...GRR...IND...LOT...ILX...LSX...DVN... LAT...LON 38828765 38718868 38918905 39628955 39998986 40269003 40668975 41248906 41698817 42238631 42058597 41788572 41378574 40628592 40218623 39618689 38828765 MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 INRead more
SPC MD 1344
MD 1344 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF THE MID-ATLANTIC STATES
Mesoscale Discussion 1344 NWS Storm Prediction Center Norman OK 1036 AM CDT Wed Jun 18 2025 Areas affected...parts of the Mid-Atlantic States Concerning...Severe potential...Watch possible Valid 181536Z - 181730Z Probability of Watch Issuance...40 percent SUMMARY...The threat for damaging winds should increase this afternoon as isolated to scattered thunderstorms form off parts of the Blue Ridge towards coastal New Jersey and Delaware. Area is being monitored for a possible Severe Thunderstorm Watch with uncertainty on overall coverage/intensity for severe gusts. An upgrade to Slight Risk is likely with the 1630Z Day 1 Outlook. DISCUSSION...Initial low-topped convection has been slowly bubbling across far northern VA and the eastern WV Panhandle. Airmass immediately downstream appears uncapped per mesoanalysis and modified 12Z soundings, where surface temperatures have warmed into the low to mid 80s. 12Z guidance is consistent in suggesting isolated to scattered thunderstorms developing within a region of enhanced 700-500 mb west-southwesterlies. This should provide sufficient speed shear for a few transient cells with mid-level rotation. With poor mid-level lapse rates, hail magnitudes should remain small. But if stratus across the northern Chesapeake/Delaware Bays vicinity can break up this afternoon, a greater than isolated damaging wind threat may be realized. ..Grams/Hart.. 06/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...CTP...LWX... LAT...LON 39067797 39677750 40097619 40037514 39707417 39247463 38967537 38627599 38577660 38597727 38767779 39067797 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 INRead more